JP6070586B2 - Method for assembling engine valve gear - Google Patents

Description

  The present invention includes a cylindrical cam element portion that is coupled to a cam shaft in a rotational direction and is fitted so as to be capable of shifting (moving) in the cam shaft direction and has two cam portions for opening and closing the valve. In the valve operating apparatus for an engine, wherein the cam portion for opening and closing the valve is switched between the two valve opening and closing cam portions by shifting the element portion to one side or the other side in the cam shaft direction. The present invention belongs to a technical field relating to a method for assembling an engine valve operating apparatus in which an element part is assembled to the camshaft.

  2. Description of the Related Art Conventionally, as a valve operating device for an engine, a plurality of cam portions having different nose shapes for one valve are provided, and by selecting a cam portion for opening and closing the valve from the plurality of cam portions, an intake valve and It is known that the valve opening amount or opening / closing timing of the exhaust valve can be switched according to the operating state of the engine.

  For example, in the valve operating device described in Patent Document 1, end cams for shifting the cam element portion are formed on both end surfaces in the cam axis direction of the cam element portion, A switching member that engages with each end face cam is provided, and the valve is opened and closed by operating the switching member to engage with the end face cam and shifting the cam element portion to one side or the other side in the cam shaft direction. The cam part is switched. Patent Document 1 discloses that the cam element portion is held at a predetermined position by a detent mechanism.

US Patent Application Publication No. 2011/02226205

  By the way, in the valve operating apparatus as described above, when the cam element portion is shifted to one side in the cam shaft direction, the cam element portion is held at the first predetermined position, and the cam element portion is moved to the other side in the cam shaft direction. It is conceivable to provide a detent mechanism for holding the cam element portion at a second predetermined position located on the other side of the first predetermined position when the shift is made. Such a detent mechanism is usually located in a detent cam portion provided on the inner peripheral surface of the cam element portion and partly in a hole formed in the cam shaft, and is pressed against the detent cam portion by an elastic member. The detent cam portion is fitted into the detent cam portion when the cam element portion is located at the first predetermined position and when the cam element portion is located at the second predetermined position, respectively. Has two grooves. Of these two grooves, the side wall portion on the other side of the groove located on the other side in the cam shaft direction constitutes a restricting portion that restricts the shift of the cam element portion to the one side. When the cam element portion is shifted to the one side in the cam shaft direction, the cam element portion is accurately held at the first predetermined position. Further, the side wall portion on the one side of the groove located on the one side in the cam shaft direction of the two grooves constitutes a restricting portion that restricts the shift of the cam element portion to the other side, Thus, when the cam element portion is shifted to the other side in the cam shaft direction, the cam element portion is accurately held at the second predetermined position.

  Here, when only one detent mechanism as described above is provided for a single cam element portion, when assembling the cam element portion to the cam shaft, an elastic member and With the pressing member set, the cam element portion is inserted into the cam shaft from the other end (or the one side) of the cam shaft, and the cam element portion is moved to the one side (or the other side). By moving, the pressing member is fitted into one of the two grooves. In this case, for example, when the cam element portion is inserted into the cam shaft from the other end of the cam shaft and the cam element portion is moved to the one side, the detent cam portion on the inner peripheral surface of the cam element portion If the inclined portion that presses the pressing member toward the hole side in accordance with the movement of the cam element portion toward the one side is formed in the one side portion of the cam member portion, the pressing member is moved by the movement of the cam element portion. It can be easily fitted in one of the two grooves.

  However, a pair of detent mechanisms may be provided for a single cam element portion. In this case, assembly of the cam element portion to the cam shaft becomes a problem. That is, for example, when the cam element portion is inserted into the cam shaft from the other end of the cam shaft and the cam element portion is moved to the one side, the pressing member on the other side of the pair of detent mechanisms Needs to pass through the detent cam portion on one side and reach the position of the detent cam portion on the other side. Here, when the pressing member on the other side passes through the detent cam portion on the one side, it passes through the restricting portion that restricts the shift of the cam element portion to the one side. Is to restrict the shift of the cam element part to the one side, so that even if the cam element part is moved to the one side, the pressing member on the other side is caught by the restriction part, and as a result, It is not easy for the other pressing member to pass through the restricting portion.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a camshaft when a pair of detent mechanisms are provided for a single cam element portion in the valve operating device as described above. This is to improve the assembling property of the cam element portion.

  In order to achieve the above object, in the present invention, a cylindrical cam element that is coupled to a cam shaft in a rotational direction and is fitted so as to be shiftable in the cam shaft direction and has two valve opening and closing cam portions. Of the engine, wherein the cam portion for opening and closing the valve is switched among the two valve opening and closing cam portions by shifting the cam element portion to one side or the other side in the cam shaft direction. In the valve device, when the cam element portion is shifted to one side in the cam shaft direction, the valve operating device is intended for an assembling method of the valve operating device of the engine in which the cam element portion is assembled to the cam shaft. When the cam element portion is held at the first predetermined position and the cam element portion is shifted to the other side in the cam shaft direction, the cam element portion is positioned at the second side that is located on the other side from the first predetermined position. A single cam element to hold in place A pair of detent mechanisms, wherein one of the pair of detent mechanisms includes a first detent cam portion provided on an inner peripheral surface of the cam element portion and a part of the cam shaft. The first detent cam portion is pressed by the first elastic member and the other detent mechanism is the inner peripheral surface of the cam element portion. A second detent cam portion provided on the second detent cam portion, a portion of the second detent cam portion positioned in a second hole formed in the cam shaft, and a second pressing member pressed against the second detent cam portion by a second elastic member; The first detent cam portion is located on the other side in the cam shaft direction with respect to the one detent mechanism, and the first detent cam portion is the first detent mechanism when the cam element portion is located at the first predetermined position. A first groove into which the pressing member is fitted; and A second groove which is located on the one side in the cam shaft direction with respect to one groove and into which the first pressing member is fitted when the cam element portion is located at the second predetermined position. The detent cam portion is located on the other side in the cam shaft direction with respect to the third groove into which the second pressing member is fitted when the cam element portion is located at the second predetermined position. A fourth groove into which the second pressing member is fitted when the cam element portion is located at the first predetermined position, and the other side wall portion of the first groove is formed on the cam element portion. A restricting portion that restricts the shift to the one side is configured, a first setting step of setting the first elastic member and the first pressing member in the first hole, and the second elasticity in the second hole. A second setting step for setting the member and the second pressing member, and the cam element portion from the other end of the cam shaft. The first pressing member set in the first setting step is fitted into the second groove by being inserted into the cam shaft and the cam element portion is moved to the one side, and is set in the second setting step. And a cam element part assembling step for fitting the second pressing member into the third groove through the restricting portion of the first groove, and in the cam element part assembling step, the second pressing member is the first pressing member. When passing through the restriction portion of one groove, the second pressing member is pressed toward the second hole by the pressing tool protruding from the bottom portion of the first groove.

  By the above method, when the second pressing member passes through the restricting portion of the first groove in the cam element portion assembling step, the second pressing member is moved by the pressing tool protruding from the bottom of the first groove. Since it presses to the 2nd hole side, the 2nd press member passes easily the control part of the 1st groove, without being caught in the control part of the 1st groove. As a result, the assembling property of the cam element portion with respect to the cam shaft can be improved. Further, if a through hole extending from the outer peripheral surface of the cam element portion to the bottom of the first groove on the inner peripheral surface is formed in the cam element portion, the pusher is inserted into the first groove through the through hole. It becomes possible to make it protrude from a bottom part. If the pusher is removed after assembly, this through hole becomes a lubricating oil supply hole to the inside of the cam element portion. Through this through hole, the fitting portion (the cam element portion is connected to the cam shaft and the cam element portion). Lubricating oil is satisfactorily supplied to a fitting portion that is coupled to the camshaft in the rotational direction and can be shifted in the camshaft direction) and a pair of detent mechanisms.

  According to another assembling method of the present invention, a cylindrical cam element portion that is coupled to the cam shaft in the rotational direction and is fitted so as to be shiftable in the cam shaft direction and has two valve opening and closing cam portions. A valve for an engine that switches a cam part for opening and closing the valve among the two valve opening and closing cam parts by shifting the cam element part to one side or the other side in the cam shaft direction In the device, for the assembling method of the valve operating device for the engine, in which the cam element portion is assembled to the cam shaft, the valve operating device is configured such that when the cam element portion is shifted to one side in the cam shaft direction, When the cam element portion is held at the first predetermined position and the cam element portion is shifted to the other side in the cam shaft direction, the cam element portion is positioned at the second predetermined position located on the other side of the first predetermined position. For a single cam element to hold in position The detent mechanism further includes a pair of detent mechanisms, and one of the pair of detent mechanisms includes a first detent cam portion provided on an inner peripheral surface of the cam element portion, and a part thereof on the cam shaft. A first pressing member that is positioned in the formed first hole and pressed by the first elastic member to the first detent cam portion, and the other detent mechanism is provided on the inner peripheral surface of the cam element portion. A second detent cam portion provided, and a second pressing member partially located in a second hole formed in the cam shaft and pressed against the second detent cam portion by a second elastic member. And the first detent cam portion is located on the other side in the cam shaft direction than the one detent mechanism, and the first detent cam portion is located on the first pressing position when the cam element portion is located at the first predetermined position. A first groove into which the member fits, and the first groove The second detent cam portion having a second groove which is located on the one side in the cam shaft direction and into which the first pressing member is fitted when the cam element portion is located at the second predetermined position. A third groove into which the second pressing member is fitted when the cam element portion is located at the second predetermined position, and the cam groove is located on the other side in the cam shaft direction with respect to the third groove. A fourth groove into which the second pressing member is fitted when the element portion is located at the first predetermined position, and the one side wall portion of the third groove is the other side of the cam element portion. And a first setting step of setting the first elastic member and the first pressing member in the first hole, and the second elastic member and the second in the second hole. 2 a second setting step of setting the pressing member, and the cam element portion from the one end of the cam shaft to the cam shaft By inserting and moving the cam element portion to the other side in the cam shaft direction, the second pressing member set in the second setting step is fitted in the fourth groove and set in the first setting step. A cam element assembly process that allows the first pressing member to pass through the restriction portion of the third groove and fit into the first groove. In the cam element assembly process, the first pressing member is When passing through the restricting portion of the third groove, the first pressing member is pressed toward the first hole by the pressing tool protruding from the bottom of the third groove.

  Also with this method, it is possible to improve the assembling property of the cam element portion with respect to the cam shaft, and to satisfactorily supply the lubricating oil to the fitting portion between the cam shaft and the cam element portion and the pair of detent mechanisms. Will be able to.

  In the method of assembling the valve gear for an engine, the cam element portion is assembled before the cam element portion assembling step, and the cam element portion is assembled after the cam element portion is assembled. It is preferable to further include a step of removing the pressing tool from the element portion.

  As a result, the operator can complete the assembly of the cam element portion to the cam shaft by inserting the cam element portion into the cam shaft and moving the cam element portion. Thus, it is not necessary to press the second pressing member to the second hole side with the pressing tool. Further, by mounting the pusher on the cam element portion, the amount of protrusion of the pusher from the bottom of the first groove can be made constant at all times. Therefore, the cam element portion can be assembled to the cam shaft stably and easily.

  As explained above, according to the method for assembling the valve gear for an engine of the present invention, when the second pressing member passes through the restricting portion of the first groove in the cam element portion assembling step, the first groove The second pressing member is pressed toward the second hole by a pressing tool protruding from the bottom of the first groove, or when the first pressing member passes through the restriction portion of the third groove, the bottom of the third groove When a pair of detent mechanisms are provided for a single cam element portion by pressing the first pressing member toward the first hole with a pressing tool protruding from the cam element, the cam element with respect to the cam shaft As a result, the lubricating oil can be satisfactorily supplied to the fitting portion between the cam shaft and the cam element portion and the pair of detent mechanisms.

1 is a side view showing a schematic configuration of an exhaust valve operating device for an engine to which an assembling method according to an embodiment of the present invention is applied. It is a front view of the said valve operating apparatus by the II direction arrow of FIG. It is the expanded sectional view cut | disconnected along the III-III line of FIG. FIG. 2 is a view corresponding to FIG. 1 showing a state where a cam portion for opening and closing a valve is switched from the state of FIG. 1. It is a perspective view which shows a cam element part. It is a side view which shows the cam element part of a 1st cylinder (or 4th cylinder). (A) is a front view of the cam element part of a 1st cylinder, (b) is a rear view of the cam element part of a 1st cylinder. It is a side view which shows the cam element part of a 2nd cylinder (or 3rd cylinder). (A) is a front view of the cam element part of a 2nd cylinder, (b) is a rear view of the cam element part of a 2nd cylinder. FIG. 6 is an enlarged development view of a main part developed along the circumference of the end face cam, showing the positional relationship between each end face cam and the switching member when the cam element parts of the third and fourth cylinders are separated from each other. FIG. 6 is an enlarged development view of a main part developed along the circumference of the end face cam, showing the positional relationship between each end face cam and the switching member when the cam element parts of the third and fourth cylinders are brought close to each other. It is sectional drawing which shows the structure of a detent mechanism in detail, Comprising: The 1st cam element part shows the state located in the 2nd predetermined position. FIG. 13 is a view corresponding to FIG. 12 showing a state in which the first cam element portion is being shifted from the second predetermined position to the first predetermined position (a state where the first detent ball has just passed over the first top portion). It is an enlarged view which shows the periphery of the 2nd detent cam part of FIG. FIG. 13 is a view corresponding to FIG. 12 showing a state in which the first cam element portion is located at the first predetermined position. FIG. 13 is a view corresponding to FIG. 12 illustrating a state in which the first cam element portion is being shifted from the first predetermined position to the second predetermined position (a state in which the second extent ball has just passed over the second top portion). It is a perspective view which shows the state which is going to mount | wear with a pushing tool to the 1st cam element part. A state in which the first cam element portion with the pusher is inserted from the front end of the cam shaft and the first cam element portion is moved to the rear side of the cam shaft (the second detent ball is moved to the rear inclined portion) It is a principal part sectional view showing the state which contacted. It is principal part sectional drawing which shows the state by which the 2nd detent ball which reached the position of the 1st groove | channel is pressed by the 2nd hole side with the pressing tool. It is principal part sectional drawing which shows the state which the 1st detent ball contact | abutted to the rear part inclination part. When removing a 1st cam element part from a cam shaft, it is principal part sectional drawing which shows the state by which the 2nd detent ball is pressed by the 1st hole side with the pressing tool. In the case where the first cam element portion is assembled to the cam shaft by inserting the first cam element portion from the rear end of the cam shaft and moving the first cam element portion to the front side of the cam shaft, It is principal part sectional drawing which shows the state in which the 1st detent ball which reached the position of the groove | channel is pressed by the 1st hole side with the pressing tool. It is principal part sectional drawing which shows the modification of a pushing tool.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, a valve operating device for a four-cylinder, four-valve DOHC engine will be described as an example.

FIG. 1 shows a configuration of an exhaust side valve operating apparatus to which an assembling method according to an embodiment of the present invention is applied. The valve operating device in the cylinder head (not shown), a total of eight exhaust valves A two by two for each of the first to fourth cylinders 1 ₁ to 1 _4, return to urge each of these exhaust valves A in the closing direction Spring B. In addition, the valve gear includes a cam shaft 2 that opens each exhaust valve A against the urging force of the return spring B via the rocker arm C at the upper part of the cylinder head. In the above valve system, the first cylinder 1 ₁ side of the cylinder row refers to the (right side in FIG. 1) and the front side, the fourth cylinder 1 ₄ side (the left side Fig. 1) of the rear side.

The cam shaft 2, the bearing composed of a cap member E attached to an upper portion of the vertical wall portion D and the respective vertical wall portions D respectively provided at the center position of each cylinder 1 ₁ to 1 ₄ in the cylinder head The part F is rotatably supported by the part F, and is rotationally driven through a chain by a crankshaft (not shown).

Cylindrical first to fourth cam element portions 20 _{1 to} 20 ₄ are spline-fitted to the cam shaft 2. Thus, the first through fourth cam elements 20 ₁ to 20 ₄ is coupled to the rotational direction relative to the cam shaft 2 (rotating integrally) and are fitted to be shifted in the camshaft direction (movement) It will be. A portion where each of the cam element portions 20 _{1 to} 20 ₄ is spline-fitted with the cam shaft 2 is a first detent cam portion 45 and a second detent cam portion 46 which will be described later on the inner peripheral surface of the cam element portions 20 _{1 to} 20 _4. The part between. Cam elements ₂₀ 1 to 20 ₄ so as to correspond respectively to the cylinders ₁ 1 to 1 ₄ are arranged in rows in the cam axial direction on the cam shaft 2.

The valve gear is provided with electromagnetic _first to _sixth switching devices 30 ₁ to 30 ₆ for shifting the cam element portions 20 _{1 to} 20 ₄ by a predetermined stroke on the cam shaft 2. . Specifically, the first switching device 30 ₁ to the position of the first cylinder _{1 1} of the front (first front cam element 20 _1), first and second cylinders ₁ 1, ₁ between the ₂ (first and the second cam elements ₂₀ 1, 20 second switching device 30 ₂ to the position of ₂ between) is, the second and third cylinders ₁ 2, ₁ between ₃ (the second and third cam elements ₂₀ 2, 20 ₃ between the third switching device 30 to the position of) _3, to its immediately rear position and the fourth switching device 30 _4, third and fourth cylinder ₁ 3, between _{1 4} (third and fourth cam elements 20 ₃ , the fifth switching device 30 ₅ to the position of 20 ₄ between), the sixth switching device 30 ₆ to the position of the rear side of the fourth cylinder _{1 4} (fourth side after the cam element 20 ₁₎ are arranged ing.

As shown in FIG. 2, the first to sixth switching device ₃₀ 1 to 30 _6, the opposite side of the cam follower C 'in the rocker arm C across the cam shaft 2, said sixth switching device ₃₀ 1 switching member 32 (described later) is arranged to direct the axis of the cam shaft 2 at 30 _6. In the present embodiment, the first to sixth switching devices 30 ₁ to 30 ₆ are attached to a cylinder head cover G that covers the cam shaft 2 and the cam element portions 20 _{1 to} 20 ₄ from above.

Each of the switching devices 30 ₁ to 30 ₆ includes a main body 31 provided with an electromagnetic actuator therein, and a substantially circular cross section that can protrude downward from the main body 31 toward the camshaft 2 when the electromagnetic actuator is energized. The pin-shaped switching member 32 is provided. In a state where the electromagnetic actuator is not energized, the switching member 32 is held at the upper inoperative position by a permanent magnet provided in the main body 31, as indicated by a broken line in FIG. On the other hand, when the electromagnetic actuator is energized, the switching member 32 protrudes downward against the permanent magnet and advances to the operating position as shown by a solid line in FIG. When the switching member 32 advances to the operating position, the cam element moves to a facing position of an end face cam 23 (described later) provided on the front end surface or the rear end surface of the cam element portion corresponding to the switching member 32. The cam element portion is shifted rearward in the cam axial direction by engaging with the end surface cam 23 on the front end surface of the cam portion, and the cam element portion is engaged with the end surface cam 23 on the rear end surface of the cam element portion. The element part is shifted to the front side in the camshaft direction.

The first switching device 30 ₁ of the switching member 32, when in the working position, the first cam element 20 ₁ is shifted to the rear side of the cam axis. The second switching device 30 _{and second} switching member 32, when in the working position, the first cam element 20 ₁ with shifting to the front side of the cam axis, the second cam element 20 ₂ after the camshaft direction Shift to the side. The third switching device 30 _third switching member 32, when in the working position, the second cam element 20 ₂ is shifted to the front side of the cam axis. The fourth switching device 30 _fourth switching member 32, when in the working position, the third cam element 20 ₃ is shifted to the rear side of the cam axis. Switching member 32 of the fifth switching device 30 _5, when in the working position, the third cam element 20 ₃ with shifting to the front side of the cam axis, the fourth cam element 20 ₄ after the camshaft direction Shift to the side. Sixth switching device 30 ₆ switching member 32, when in the operative position, to the fourth shift the cam element 20 ₄ to the front side of the cam axis.

Energization of the respective switching device 30 1 _{to 30} 6 _{(electromagnetic} actuator) based on the detection signal from the engine rotational angle sensor (not shown), to predetermined engine rotational angle period, the switching by a computer (not shown) device 30 ₁ to 30 ₆ is performed by energization instruction to ₆ .

Further, in the valve gear, the switching device ₃₀ 1 to 30 ₆ each cam elements ₂₀ 1 to 20 ₄ of the cam axis of the cam elements after shift ₂₀ 1 to 20 ₄ to predetermined two positions by (first In order to perform positioning and holding at a predetermined position and a second predetermined position), as shown in FIG. 3 by way of example of the first and second cam element portions 20 ₁ and 20 ₂ , the cam shaft 2 and the cam element portions 20 _{1 to} 20. Detent mechanisms 40 are respectively provided on both sides of the spline fitting portion ₄ with respect to the cam shaft direction. A pair of detent mechanisms 40 are provided for a single cam element portion. Hereinafter, when distinguishing a pair of detent mechanisms 40, one is called the 1st detent mechanism 40a, and the other is called the 2nd detent mechanism 40b, and when not distinguishing, it is only called the detent mechanism 40.

The first detent mechanism 40a is first pressed to the first Ditentokamu portion 45 provided on the inner peripheral surface of the cam elements 20 ₁ to 20 _4, is pressed by the elastic urging the first Ditentokamu 45 It has the 1st detent ball 43a as a member. A part of the first detent ball 43a (a portion on the camshaft 2 side) is located in a first hole 41a formed in the camshaft 2, and a first spring is located on the inner side of the first hole 41a. 42a is accommodated, and the first detent ball 43a is pressed against the first detent cam portion 45 by the first spring 42a.

The second detent mechanism 40b includes first and second Ditentokamu portion 46 provided on the inner peripheral surface of the cam elements 20 ₁ to 20 _4, is pressed by the elastic urging the second Ditentokamu 46 It has the 2nd detent ball 43b as 2 press members. A part of the second detent ball 43b (portion on the camshaft 2 side) is located in a second hole 41b formed in the camshaft 2, and a second spring is located on the back side in the second hole 41b. 42b is accommodated, and the second detent ball 43b is pressed against the second detent cam portion 46 by the second spring 42b.

The first detent cam portion 45 includes a first groove 51 and a second groove 52 that are arranged adjacent to each other in the cam shaft direction and engage with the first detent ball 43a, and a boundary between the grooves 51 and 52. The second detent cam portion 46 is arranged adjacent to the cam shaft direction and the third detent ball 43b is engaged with the second detent ball 43b. 54 and a second apex 56 located at the boundary between the grooves 53 and 54. The first groove 51, second groove 52, third groove 53 and fourth groove 54 is provided over the entire circumference on the inner peripheral surface of the cam elements ₂₀ 1 to 20 _4.

In the first cam element 20 ₁ and the third cam element 20 _3, the second detent mechanism 40b is located on the front side of the cam axis relative to the first detent mechanism 40a, the second cam element 20 ₂ and in the fourth cam element 20 _4, the second detent mechanism 40b is located on the rear side of the cam shaft direction with respect to the first detent mechanism 40a. In the first cam element 20 ₁ and the third cam element 20 _3, the second groove 52 is located on the rear side of the cam shaft direction via the first apex 55 relative to the first groove 51, in the second cam element 20 ₂ and the fourth cam element 20 _4, the second groove 52 through the first apex 55 positioned on the front side of the cam shaft direction with respect to the first groove 51. Further, in the first cam element 20 ₁ and the third cam element 20 _3, fourth groove 54 is located on the front side of the cam shaft direction with respect to the third groove 53 through the second apex portion 56, the in 2 cam element 20 ₂ and the fourth cam element 20 _4, the fourth groove 54, the third groove 53 through the second apex 56 positioned on the rear side of the camshaft direction. Thus, the first cam element 20 ₁ and the third cam element 20 _3, with the second cam element 20 ₂ and the fourth cam element 20 _4, context is reversed.

When the first detent ball 43a is and fits into the first groove 51 second detent ball 43b is fitted in the fourth groove 54, the cam elements ₂₀ 1 to 20 _4, a shown in FIGS. 1 and 3 1 Positioned and held at a predetermined position. Meanwhile, when the first detent ball 43a is and fits into the second groove 52 and the second detent ball 43b is fitted in the third groove 53, the cam elements ₂₀ 1 to 20 _4, a shown in FIG. 4 2 It is positioned and held at a predetermined position.

Here, as shown in FIG. 1, when the first to fourth cam elements 20 ₁ to 20 ₄ are positioned in the first predetermined position all, the first cam element 20 ₁ is the rear side, the second cam element part 20 ₂ on the front side, the third cam element 20 ₃ rear, fourth cam element 20 ₄ are located respectively on the front side. Therefore, when the first to fourth cam elements ₂₀ 1 to 20 ₄ are located in all of the first predetermined position, the first and second cam elements ₂₀ 1, 20 ₂ opposing end faces close to each other, the second and The opposed end surfaces of the third cam element portions 20 ₂ and 20 ₃ are separated from each other, and the opposed end surfaces of the third and fourth cam element portions 20 ₃ and 20 ₄ are close to each other.

Further, as shown in FIG. 4, when the first to fourth cam elements ₂₀ 1 to 20 ₄ are positioned in the second predetermined position all the first cam element 20 ₁ is the front side, the second cam element 20 ₂ is rear, third cam element 20 ₃ on the front side, the fourth cam element 20 ₄ respectively positioned on the rear side. Therefore, when the first to fourth cam elements ₂₀ 1 to 20 ₄ is positioned in every second predetermined position, the first and second cam elements ₂₀ 1, 20 ₂ of the facing end surface is spaced from each other, the second and The opposing end surfaces of the third cam element portions 20 ₂ and 20 ₃ are close to each other, and the opposing end surfaces of the third and fourth cam element portions 20 ₃ and 20 ₄ are in a state of being separated from each other.

Thus the first cam element 20 ₁ and the third cam element 20 _3, Figure 1, when it is shifted to the left (rear) of FIG. 3 and FIG. 4, is positioned in the first predetermined position, when it is shifted to the right side (front side), while positioned in the second predetermined position, the second cam element 20 ₂ and the fourth cam element 20 _4, when it is shifted to the right side (front side), the 1 When positioned at a predetermined position and shifted to the left side (rear side), it is positioned at a second predetermined position. Thus, for the first cam element 20 ₁ and the third cam element 20 _3, FIG. 1, the left side of FIG. 3 and FIG. 4 (rear side), referred to in the present invention, on one side of the cam axis The right side (front side) corresponds to the other side in the cam shaft direction in the present invention. On the other hand, the second cam element 20 ₂ and the fourth cam element 20 _4, FIG. 1, the right (front) of FIGS. 3 and 4, referred to in the present invention, it corresponds to one side of the cam axis The left side (rear side) corresponds to the other side in the cam shaft direction in the present invention.

Next, FIGS. 5 to 9, the configuration of the cam elements ₂₀ 1 to 20 _4, a first example cam element 20 ₁ and the second cam element 20 ₂ is described in detail.

The outer peripheral surface of the cylindrical cam element 20 1 ₍₂₀ 2 _{to 20 4)} in the cylinder axial direction (coincident with the camshaft direction) intermediate section is a journal portion 21 which is supported by the bearing portion F, the cylindrical shaft Two exhaust valves A, A opening / closing operation parts 22 for the corresponding cylinders are provided on both sides in the direction (front and rear sides in the camshaft direction), as shown in FIG. to, for example, the lift amount for the time of low engine rotation is ₁ large first cam portion 22, for example, lift for during high engine rotation is provided adjacent the smaller second cam portion 22 ₂ phases.

  Step portions 25 having a diameter larger than that of the journal portion 21 are formed at the boundary portions between the journal portion 21 and the respective operation portions 22.

These first cam portion 22 ₁ and the second cam portion 22 _2, as shown in FIG. 7 (b), based in circles a common lift amount differs nose portion _b 1, _{b 2} is the base circle on a Are provided with a slight phase difference. As the first cam portion 22 ₁ and the second cam portion 22 _2, between the two places actuating portions 22, the order and the nose portion _b 1 aligned in the longitudinal direction, _{b 2} of the phases match, The operating parts 22 are provided respectively. The base circle a as is common, the base circle diameter of the base circle a of the first cam portion 22 ₁ and the second cam portion 22 ₂ is meant to be the same.

In the first cam element 20 ₁ and the third cam element 20 _3, the first cam portion 22 ₁ is the front side, are arranged on the second cam portion 22 ₂ is the rear side, the second cam element 20 ₂ and in the fourth cam element 20 _4, the second cam portion 22 ₂ on the front side, are arranged on the first cam portion 22 ₁ is the rear side.

The cam elements ₂₀ 1 to 20 _4, when it is positioned and held at the first predetermined position on the cam shaft 2 by the detent mechanism 40, in any of the cam elements ₂₀ 1 to 20 _4, the two first cam portions ₂₂ 1, 22 _1, two rocker arms C of the corresponding cylinder ₁ 1 to 1 _4, the cam follower C of C ', C' respectively corresponding position (see FIG. 1), second predetermined on the cam shaft 2 when positioned and held in position, the second cam portion ₂₂ 2, 22 _2, two rocker arms C of the corresponding cylinder ₁ 1 to 1 _4, the cam follower of the C C ', C' corresponding respectively located (FIG. 4 See). Thus, the shift to the front or rear side of the cam axis of the cam elements 20 ₁ to 20 _4, in the first cam portion 22 ₁ and the second cam portion 22 _2, switching cam section for opening and closing the valve Will be.

Here, in the engine according to the present embodiment, the order of explosion (combustion) of each cylinder is as follows: 3rd cylinder 1 ₃ → 4th cylinder 1 ₄ → 2nd cylinder 1 ₂ → 1st cylinder 11 ₁ nose portion _b 1, _{b 2} of the cam elements ₂₀ 1 to 20 ₄ of the first cam portion 22 ₁ and the second cam portion 22 _2, for each 90 ° rotation cam shaft 2, the cam follower C 'in this order, C The first to fourth cam element portions 20 _{1 to} 20 ₄ are spline-fitted to the cam shaft 2 with a phase difference so as to be positioned corresponding to '.

In addition, each cam elements ₂₀ 1 to 20 _4, the end face cam 23 in both front and rear end faces are provided.

As shown in FIGS. 6 and 8, the end face cams 23 and 23 on the front and rear end faces of each of the cam element portions 20 _{1 to} 20 ₄ are lifts projecting from the reference surfaces 23a and 23a to the front and rear sides in the cam shaft direction, respectively. It has parts 23b and 23b. In FIG. 6, as the first cam element 20 _1, the left side of FIG. 6 is the front and becomes right rear side of FIG. 6, the fourth cam element 20 _4, the right side of FIG. 6 The front side and the left side of FIG. 6 are the rear side. Further, in FIG. 8, the second cam element 20 _2, the left side of FIG. 8 is a right rear becomes and 8 on the front side, the third cam element 20 _3, the right side of FIG. 8 The front side and the left side of FIG. 8 are the rear side.

  As shown in FIGS. 7 and 9, each lift portion 23b has a reference surface 23a with respect to the rotational direction X within a predetermined phase range α (for example, about 120 °) from the lift start position e to the lift end position f. The lift amount in the camshaft direction gradually increases from (lift amount zero) and returns to the reference surface 23a at a lift end position f or a slope end position g described later.

Each cam element portion 20 _{1 to} 20 ₄ includes end face cams 23 at both front and rear end faces, as is apparent from a comparison of FIGS. 7A and 7B (or FIGS. 9A and 9B). 23 lift end positions f are in different phases. That is, the end face cam 23 of both end faces of the cam elements ₂₀ 1 to 20 _4, the maximum lift of the both end face cam 23 is formed so as to be different from the rotation direction of the phase.

The end face cam 23 of both end faces of the cam elements 20 ₁ to 20 _4, the maximum value Lmax of the distance along the camshaft direction between the cam surfaces of the both end face cam 23 in the same phase The distance between the switching members 32 and 32 (the switching members 32 and 32 engaged with the cam surfaces of the both end face cams 23 and 23) when the both are located at the operating position is less than the distance Lpin along the cam shaft direction. Is formed. That is, there is no phase in which the distance along the cam axis direction between the cam surfaces of the end face cams 23, 23 on both end faces is greater than the distance Lpin along the cam axis direction between the switching members 32, 32.

Furthermore, in the present embodiment, FIGS. 7 (a) and (b) (or FIG. 9 (a) and (b)) As is clear from compare and both end faces of each cam elements ₂₀ 1 to 20 ₄ The lift portions 23b, 23b of the end face cams 23, 23 are such that the phase range α from the lift start position e to the lift end position f overlaps at least a part of the phase range β (shown in FIGS. 10 and 11). Is formed.

Further, as described above, that each cam elements 20 ₁ to 20 ₄ are splined to the camshaft 2 respectively provided a predetermined phase difference in accordance with the firing order of the cylinders 1 ₁ to 1 ₄ As a result, the end face cams 23 and 23 of the cam element portions 20 _{1 to} 20 ₄ that face each other also face each other with a phase difference. In the present embodiment, as shown by reference numerals a and b in FIG. 1, two adjacent first and second cam element portions 20 ₁ and 20 ₂ and third and fourth cam element portions 20 ₃ and 20 are provided. ₄ is provided so that the lift portions 23b, 23b of the end cams 23, 23 facing each other have different phases, and the two cam element portions 20 ₁ , 20 ₂ ; 20 ₃ , 20 ₄ adjacent to each other. At least a part of the lift portions 23b, 23b facing each other when close to each other overlaps in the cam shaft direction. At this time, the minimum value of the distance along the cam shaft direction between the cam surfaces in the same phase of the end face cams 23 and 23 facing each other is configured to be equal to or smaller than the diameter of the switching member 32.

Then, the second and fifth switching device ₃₀ 2, 30 ₅ switching member 32 and 32, two cam elements which they correspond _{20 1,} 20 _2; 20 3, 20 ₄ end cam facing each other at the proximity of the The two cam element portions 20 ₁ , 20 that are close to each other as the cam shaft 2 rotates by advancing to a position (operating position) between the opposing surfaces 23, 23 and engaging with these end face cams 23, 23. ₂ ; 20 ₃ , 20 ₄ are shifted in a direction in which they are separated from each other.

At this time, the first and second cam element portions 20 ₁ and 20 ₂ , and the third and fourth cam element portions 20 ₃ and 20 ₄ that are close to each other in the state shown in FIG. 1 are separated from each other. , Both shift from the first predetermined position to the second predetermined position shown in FIG. The second and third cam elements 20 _2, 20 ₃ which has been spaced apart from each other in the state shown in FIG. 1 will be close to each other.

On the other hand, the first switching device 30 ₁ of the switching member 32, as shown in FIG. 4, in a state the first cam element 20 ₁ is in the second predetermined position of the front, first the front end of the cam element 20 ₁ engages the end face cam 23 by advancing a position facing the end face cam 23 faces to the (operative position), in accordance with the rotation of the cam shaft 2, the first predetermined position of the rear side of the first cam element 20 ₁ Shift. Similarly, the fourth switching device 30 _fourth switching member 32 is in a state the third cam element 20 ₃ is in the second predetermined position of the front, the end cam 23 of the front end surface of the third cam element 20 ₃ It engages the end face cam 23 by entry into confronting position (operating position), in accordance with the rotation of the cam shaft 2, to the third shift to the first predetermined position after side cam element 20 _3.

The third switching device 30 _third switching member 32 is in the state in the second predetermined position of the second cam element 20 ₂ is rear, to the second end cam 23 on the rear end face of the cam element 20 ₂ engages the end face cam 23 by entry into confronting position (operating position) shifts the second cam element 20 ₂ to the first predetermined position of the front. Similarly, the switching member 32 of the sixth switching device 30 _6, the fourth cam element 20 ₄ in the state in the second predetermined position of the rear side, the fourth cam element 20 ₄ of the rear end facet of the face cam 23 It engages the end face cam 23 by advancing to a position (operating position) facing the causes fourth shift the cam element 20 ₄ to the first predetermined position of the front.

Here, the advancement of each of the switching devices 30 ₁ to 30 ₆ to the operating position of the switching member 32 is performed at the following timing. That is, entry into the operating position of the first and fourth switching device ₃₀ 1, 30 ₄ of the switching member 32, the pointing position of該切switching member 32, the first and third front of cam elements ₂₀ 1, 20 ₃ This is performed at the timing when the reference surface 23a of the end cam 23 of the surface is located. Also, entry into the operating position of the third and sixth switching device ₃₀ 3, 30 ₆ switching member 32, the pointing position of該切switching member 32, after the second and fourth cam elements ₂₀ 2, 20 ₄ This is performed at the timing when the reference surface 23a of the end surface cam 23 of the end surface is located. Moreover, entry into the operating position of the second switching device 30 _{and second} switching member 32, the pointing position of該切switching member 32, the two end cam facing each other in the first and second cam elements 20 _1, 20 ₂ This is performed at the timing when both the reference surfaces 23a and 23a of 23 and 23 are located. Entry into the operating position of the fifth switching device 30 ₅ switching member 32, the pointing position of該切switching member 32, the third and fourth cam elements ₂₀ 3, 20 facing each other in the ₄ two end cam 23, 23 is performed at the timing when both reference surfaces 23a and 23a of 23 are located.

Further, the switching shift of each cam elements ₂₀ 1 to 20 ₄ by entry into the operating position of the switching member 32, the cam follower C 'of the rocker arm C is in the first cam portion 22 ₁ and the second cam portion 22 ₂ base circle a Must be performed when the cylinder is in a stroke other than the exhaust stroke.

Therefore, in order to satisfy these operating timing conditions, in this embodiment, as shown in FIG. 7, the tops of the nose parts b ₁ and b ₂ of the first and second cam parts 22 ₁ and 22 ₂ are used. The lift start position e of the end face cam 23 is set at a position of a predetermined phase on the front side (advance side) of the rotation direction X, and the position of the predetermined phase α on the rear side (delay side) of the rotation direction X from the lift start position e. Is set to the lift end position f of the end face cam 23. The angle from the lift start position e of the end face cam 23 to the lift end position of the nose parts b ₁ and b ₂ of the first and second cam parts 22 ₁ and 22 ₂ toward the rear side in the rotation direction X is 180 degrees. Are also provided in such a positional relationship as to be smaller. In this case, the positional relationship between the rocker arm C of the cam follower C 'and switching member 32 of the first to sixth switching device ₃₀ 1 to 30 ₆ shown in FIG. 2, the cam elements ₂₀ 1 to 20 _4, the exhaust stroke It will shift soon after the end.

In this embodiment, the end cam 23 of the cam elements 20 ₁ to 20 _4, the slope portion 23c return for forcibly retracted to the inoperative position the switching member 32 that advances to the operating position is integrally provided with Yes. The switching member 32 that has advanced to the operating position is returned to the inoperative position by the return slope portion 23c and is held in the inoperative position by the permanent magnet.

The place where the return slope portion 23c is actually provided varies depending on the switching order of the cam portions 22 ₁ and 22 ₂ of the cam element portions 20 _{1 to} 20 ₄ and the conditions such as the number of switching devices to be arranged. However, regardless of these conditions, adjacent cam element portions (this embodiment) shifted by a common (shared) switching device (in this embodiment, the second switching device 30 ₂ and the fifth switching device 30 ₅ ) are used. for embodiment, the first cam element 20 ₁ and the second cam element 20 _2, and the third cam element 20 ₃ for the fourth cam element 20 _4), at least, the shift is delayed by the common switching device It is necessary to provide a slope portion 23c on the end cam 23 of the cam element portion to be provided. In this embodiment, the same third order of cylinder _{1 3} → the fourth cylinder _{1 4} → the second cylinder _{1 2} → first cylinder _{1 1} and the combustion order, cam element ₂₀ 1 of the respective cylinders ₁ 1 to 1 ₄ 20 ₄ of the cam portion ₂₂ 1, 22 ₂ for the switch, the first of the cam element 20 ₁ and the second cam element 20 _2, being shifted with a delay by the second switching device 30 _2, the first cam an element portion 20 _1, the third of the cam element 20 ₃ and the fourth cam element 20 _4, being shifted with a delay by the fifth switching device 30 ₅ is a fourth cam elements 20 _1. In the present embodiment, the first and fourth cam elements ₂₀ 1, 20 ₄ of the end cam 23 of the front and rear end faces, and the second end cam 23 on the rear end face of the cam element 20 _2, the third cam element part 20 ₃ to the end face cam 23 of the front end surface of the back slope portion 23c, respectively.

  As shown in FIGS. 6 to 9, the return slope portion 23 c protrudes in the cam shaft direction from the lift portion 23 b, and on the cam surface of the end face cam 23, the rotation delay side (arrow X) from the lift end position f of the end face cam 23. And a cam surface extending from the lift end position f (becomes the slope start position) to the slope end position g and extending obliquely outward in the radial direction toward the rotation delay side, The cam surface has a gradually increased lift amount in the radial direction toward the rotation delay side. This cam surface has a slightly lower lift amount at the slope start position f than the front end portion of the switching member 32 in the operating position, and a front end portion of the switching member 32 in which the lift amount at the slope end position g is in the inactive position. Is set slightly lower than.

According to the return slope portion 23c, after the shift of the cam element portions 20 _{1 to} 20 ₄ by the lift portion 23b is finished, the switching member 32 is moved from the operating position by slidingly contacting the tip end portion of the switching member 32 with its cam surface. Can be retracted to the inoperative position. As described above, the lift amount at the slope end position g is lower than the tip of the switching member 32 in the inoperative position, but is given to the switching member 32 from the slope start position f to the slope end position g. The switching member 32 is returned to the inoperative position by the inertial force and the magnetic force of the permanent magnet.

  The return slope portion 23c is provided on the end face cam 23 so as to be positioned in the direction of the switching member 32 when the adjacent cam element portions are separated from each other. Further, the return slope portion 23c is configured so that, particularly when the adjacent cam element portions are close to each other, the opposite end surface cams 23, 23 do not interfere with each other, and in particular, the return slope portion 23c of one end surface cam 23 and the other end surface cam. The lift part 23b of 23 is provided so as not to interfere.

In this embodiment, the return slope portion 23c, along with the lift portion 23b, are formed integrally with the end cam 23, it returns the slope portion 23c, cam element 20 ₁ end cam 23 is provided the 20 ₄ formed as a separate component, may be integrated with cam elements ₂₀ 1 to 20 ₄ by the assembly after.

Next, the operation of the valve gear will be described with reference to FIGS. 10 and 11 show the rotation of the third and fourth cam element portions 20 ₃ and 20 ₄ with respect to the switching member 32 of the _fourth to sixth switching devices 30 ₄ to 30 _{6. 3} , 20 ₄ is a diagram showing relative movement of the switching member 32 in the circumferential direction of the end face cam 23 (from left to right in the figure). Then, at the time of closest proximity (first when in a predetermined position) of the two cam element 20 _3, 20 shows a _fourth end face cam 23 in solid lines, spaced apart at both cam element 20 ₃ of (sometimes in the second predetermined position) shows an end face cam 23 of 20 ₄ by a dashed line.

First, as shown in FIG. 1, for example, when the engine is rotating at a high speed and the first to fourth cam element portions 20 _{1 to} 20 ₄ are positioned at the first predetermined position, these cam element portions 20 ₁ to 20 ₁ . in 20 _4, both the two operating portions 22 and 22 large first cam portion ₂₂ 1 of the lift amount in the 22 _1, the rocker arm C, the cam follower of the C C ', C' correspond respectively located, cam shaft rotation of 2, in the above order, the exhaust valve a of the cylinders 1 ₁ to 1 ₄ during the exhaust stroke is opened at a relatively large opening amount.

From this state, with the decrease of the engine rotational speed, when switching so as to reduce the opening amount of the exhaust valve A, the second and fifth switching device 30 _2, 30 ₅ switching member by energizing the electromagnetic actuator 32 and 32 are advanced from the non-operating position to the operating position.

That is, first, switching member 32 of the fifth switching device 30 _5, the third and fourth cam elements 20 _3, 20 ₄ of the opposing end cam 23 In the first place is in a state close to each other, 23, it advances to a position (operating position) between 23 and engages with these end face cams 23,23. In that case, as shown at (A) in FIG. 10, switching member 32 of the fifth switching device 30 _5, third and fourth cam elements ₂₀ 3, 20 ₄ of the opposing end cam 23 ( Advancing in a period in which the lift amount (shown by a solid line) is directed to the reference planes 23a, 23a where both are zero.

After the exhaust stroke of the third cylinder 1 ₃ has been finished, the position of the fifth switching device 30 ₅ switching member 32, the lift start position e of the third cam element 20 ₃ of the rear end face of the end cam 23 is reached and, thereafter, switching member 32 of the fifth switching device 30 ₅ is in position in FIG. 10 from the code (i) to (iii), in accordance with the rotation of the cam shaft 2, the third cam element 20 ₃ of the rear end surface while sliding the lift portion 23b of the end cam 23, the third cam element 20 ₃ press the front (shown by a downward white arrow), and the third shift the cam element 20 ₃ to the side of the second predetermined position ( (Shown with a dashed line).

The third shift of cam element 20 _3, third cam element 20 ₃ of the front end face of the end cam 23, approaching the fourth switching device 30 _fourth switching member 32 in the inoperative position. Here, the third cam element 20 _3, the phase of distance along the camshaft direction of the same phase between the cam face of the end face cam 23 of both end faces thereof becomes the maximum value Lmax is the end surface of the front end face The phase at the lift end position f of the lift portion 23b of the cam 23 or the phase at the lift end position f of the lift portion 23b of the end face cam 23 on the rear end face is set. The maximum value Lmax is the third cam element 20 ₃ Distance Lpin along the camshaft direction between the both sides of the switching member 32, 32 (and have expanded to both operating position) or less (FIG. 10, Lmax <Lpin) is set. Therefore, as shown at (c) in FIG. 10, the engagement of the lift end position f of the switching member 32 of the fifth switching device 30 ₅ and the third cam element 20 ₃ of the rear end face of the end cam 23 at the time when the third cam element 20 ₃ is shifted to the most forward, working also as the fourth switching device 30 _fourth switching member 32 has been advanced to the operating position by failure or the like, the fourth switching device has issued該進30 ₄ switching member 32 is not in contact with the lift portion 23b of the third cam element 20 ₃ of the front end face of the end cam 23, then the contact by the rotation of the cam shaft 2, but at that time, the fifth switching device 30 ₅ switching member 32 has already passed through the lift end position f, Thus, the switching member 32 of the fifth switching device 30 ₅ is in contact with the third end face cam 23 of the rear end surface of the cam element 20 ₃ There is no. Thus the distance along the camshaft direction in the third same phase between the cam surfaces of the both end face cam 23 in the cam element 20 _3, while the third cam element 20 ₃ on both sides of the switching member 32, 32 since smaller than the distance Lpin along the camshaft direction, never in any phase third cam element 20 ₃ becomes unrotatable caught between both sides of the switching member 32, 32.

Also, the position of the fifth switching device 30 ₅ switching member 32, after the lift start position e of the third cam element 20 ₃ of the rear end face of the end cam 23 has reached, the camshaft 2 is rotated 90 °, the 4 the exhaust stroke of the cylinder 1 ₄ is completed, the position of the fifth switching device 30 ₅ switching member 32, the lift start position e of the fourth cam element 20 ₄ of the front end face of the end cam 23 reaches then switching member 32 of the fifth switching device 30 _5, at the position of the codes of FIG. 10 (d) to (e), in accordance with the rotation of the cam shaft 2, the end face of the front end surface of the fourth cam element 20 ₄ press the fourth cam element 20 ₄ rear while sliding the lift portion 23b of the cam 23 (upward black shown by arrow), is the fourth shift the cam element 20 ₄ to the side of the second predetermined position (a dashed line ).

The fourth shift of cam element 20 _4, the fourth cam element 20 ₄ of the rear end face of the end cam 23, approaching the switching member 32 of the sixth switching device 30 ₆ in the inoperative position. Here, similarly to the third cam element 20 _3, fourth cam element 20 ₄ is also (in FIG. 10, Lmax <Lpin) Lmax ≦ Lpin are formed such that. Therefore, as shown at (e) in FIG. 10, the engagement of the lift end position f of the switching member 32 of the fifth switching device 30 ₅ and the fourth cam element 20 ₄ of the rear end face of the end cam 23 in the sixth when the switching device 30 ₆ is shifted to the rearmost, working as switching member 32 of the sixth switching device 30 ₆ had advanced to the operating position by failure or the like, the sixth switching device are out該進30 switching member 32 of _6, 4 not in contact with the lift portion 23b of the end cam 23 of the rear end surface of the cam element 20 _4, but thereafter the contact by the rotation of the cam shaft 2, is at that time, the fifth switch switching member 32 of the device 30 ₅ is passed through the lift end position f already Therefore, switching member 32 of the fifth switching device 30 ₅ is in contact with the fourth end face cam 23 of the front end surface of the cam element 20 ₄ There is nothing. Thus fourth distance along the camshaft direction of the same phase between the cam surfaces of the both end face cam 23 in the cam element 20 _4, while the fourth cam element 20 ₄ sides of the switching member 32, 32 since smaller than the distance Lpin along the camshaft direction, never in any phase fourth cam element 20 ₄ becomes unrotatable caught between both sides of the switching member 32, 32.

Further, when the switching member 32 of the fifth switching device 30 ₅ passes the position of the code (e) in FIG. 10, stopping the energization of the electromagnetic actuator. Thereafter, in the positions from (e) to (f) in FIG. 10, the switching member 32 is pushed up while its tip end surface is in sliding contact with the cam surface of the return slope portion 23c to forcibly move to the inoperative position. Returned.

Next, the second switching device 30 _{and second} switching member 32, the end surface In the first predetermined position to the first and second cam elements ₂₀ 1, 20 ₂ opposed in a state of being close to each other cams 23 and 23 It advances to the position (operating position) between and engages with these end face cams 23 and 23. In that case, the second switching device 30 _{and second} switching member 32, first and second cam elements ₂₀ 1, 20 ₂ phases any lift of the opposite end cam 23 are 0 reference surface 23a, 23a Advance into the period that is oriented to.

After the exhaust stroke of the second cylinder 1 ₂ ends, the position of the second switching device 30 _{and second} switching member 32, the lift start position e of the second cam element 20 ₂ of the front end face of the end cam 23 is reached and, then, in accordance with the rotation of the cam shaft 2, by pressing the switching member 32 to the second cam element 20 ₂ to the rear while sliding in contact with the lift portion 23b of the end face cam 23, the second cam element 20 ₂ second Shift to the predetermined position. The second will be cam element 20 _2, it does not become unable to rotate caught between both sides of the switching member 32, 32.

Also, the position of the second switching device 30 _{and second} switching member 32, after the lift start position e of the second cam element 20 ₂ of the front end face of the end cam 23 has reached, the camshaft 2 is rotated 90 °, the When one cylinder 1 ₁ of the exhaust stroke is completed, the position of the second switching device 30 _{and second} switching member 32, the lift start position e of the first cam element 20 ₁ of the rear end face of the end cam 23 reaches, thereafter, according rotation of the cam shaft 2, the second switching device 30 _{and second} switching member 32, sliding contact with the first front side of the cam element 20 ₁ in the lift portion 23b of the first cam element 20 ₁ of the rear end face of the end cam 23 press to shifts the first cam element 20 ₁ to the side of the second office stationary. The first will be cam element 20 _1, it does not become unable to rotate caught between both sides of the switching member 32, 32.

Further, stopping the power supply to the second switching device 30 _{and second} electromagnetic actuator, then, the switching member 32, similar to the fifth switching device 30 ₅ described above, the distal end surface of the該切switching member 32 is returned in the slope portion 23c It is pushed up while being in sliding contact with the cam surface and is forcibly returned to the inoperative position.

As a result of the above-described operation, the first to fourth cam element portions 20 _{1 to} 20 ₄ are all shifted from the first predetermined position to the second predetermined position, and as shown in FIG. 4, the first to fourth cam element portions 20 _1. 20 in any ₄ also, 2 second cam portion ₂₂ of the two actuating portions 22, 22 ₂ rocker arm C, the cam follower of the C C ', C' respectively corresponding positions, each cylinder _{1 1} when the exhaust stroke ~ 1 ₄ of the exhaust valve a is to open a relatively small opening amount.

On the other hand, each of the cam elements ₂₀ 1 to 20 ₄ of the lift amount is smaller second cam section ₂₂ 2 shown in FIG. 4, 22 ₂ rocker arm from C, cam follower C ', C' states corresponding respectively located and C, for example, As the engine speed increases, the operation of switching the first cam portions 22 ₁ , 22 ₁ having a large lift amount shown in FIG. 1 to positions corresponding to the cam followers C ′, C ′ respectively is performed as the first, third, and third operations. 4 and the sixth switching devices 30 ₁ , 30 ₃ , 30 ₄ , and 30 ₆ are energized to operate the switching members 32 of the switching devices 30 ₁ , 30 ₃ , 30 ₄ , and 30 ₆ from the inoperative position. This is done by advancing to a position.

That is, first, the fourth switching device 30 _fourth switching member 32, in Figure 11 reference numeral as shown in (g), also the lift amount of the third cam element 20 ₃ of the front end face of the end cam 23 is either 0 As soon as the period directed to the reference surface 23a is entered, the end cam 23 advances to the facing position (operating position).

After the exhaust stroke of the third cylinder 1 ₃ has been finished, the position of the fourth switching device 30 _fourth switching member 32 as described above advances, the lift start position of the third cam element 20 ₃ of the front end face of the end cam 23 e reaches, thereafter, the fourth switching device 30 _fourth switching member 32 is at the position from the code (h) to (co) of FIG. 11, in accordance with the rotation of the cam shaft 2, the lift portion 23b of the end face cam 23 press third cam element 20 ₃ while sliding rearward on (shown by an upward white arrow), and the third shift the cam element 20 ₃ to the side of the first predetermined position (shown in solid lines).

The third shift of cam element 20 _3, third cam element 20 ₃ of the rear end face of the end cam 23, approaching the switching member 32 of the fifth switching device 30 ₅ in the inoperative position. Here, the third cam element 20 _3, as described above, (in FIG. 11, Lmax <Lpin) Lmax ≦ Lpin are formed such that. Therefore, on the way moving in the fourth switching device 30 _fourth switching member 32 by the third rear side of the cam element 20 _3, as shown at (h) in FIG. 11, after the third cam element 20 ₃ end cam 23 of the end face, but closest in its lift end position f to the switching member 32 of the fifth switching device 30 _5, this time, the switching member 32 is operative position of the fifth switching device 30 ₅ by operation failure or the like even though advanced, not in contact with the fifth switching device 30 ₅ switching member 32 and the third cam element 20 ₃ of the rear end face of the end cam 23 which has issued該進, then, the fourth switching device 30 by the _fourth switching member 32 is shifted to the third cam element 20 ₃ further rear, in that time, passes through the lift end position f of the switching member 32 of the fifth switching device 30 ₅ is already lift portion 23b and, Thus, the fifth switching device 30 Switching member 32 does not come into contact with the end cam 23 of the rear end surface of the third cam element 20 _3. Thus the distance along the camshaft direction in the third same phase between the cam surfaces of the both end face cam 23 in the cam element 20 _3, while the third cam element 20 ₃ on both sides of the switching member 32, 32 since smaller than the distance Lpin along the camshaft direction, never in any phase third cam element 20 ₃ becomes unrotatable caught between both sides of the switching member 32, 32.

Also, the position of the fourth switching device 30 _fourth switching member 32, after the lift start position e of the end cam 23 of the front end surface of the third cam element 20 ₃ reaches, the camshaft 2 is rotated 90 °, the 4 the exhaust stroke of the cylinder 1 ₄ ends, as shown at (Ke) in FIG. 11, switching member 32 of the sixth switching device 30 _6, after the fourth cam element 20 ₄ in the second predetermined position The end face cam 23 advances and engages with the end face cam 23 during a period in which the lift amount of the end face cam 23 is directed to the reference face 23a.

After the exhaust stroke of the fourth cylinder 1 ₄ is completed, the position of the switching member 32 of the sixth switching device 30 _6, the lift start position e of the rear end face of the end cam 23 in the fourth cam element 20 ₄ reaches and, thereafter, switching member 32 of the sixth switching device 30 _6, at the position of the codes of FIG. 11 (k) to (Shi), in accordance with the rotation of the cam shaft 2, sliding in contact with the lift portion 23b of the end face cam 23 while pressing the fourth cam element 20 ₄ to the front side (shown by the downward black arrow), to the fourth shift the cam element 20 ₄ to the side of the first predetermined position (shown in solid lines).

The fourth shift of cam element 20 _4, the end cam 23 of the front end surface of the fourth cam element 20 _4, approaching the switching member 32 of the fifth switching device 30 ₅ in the inoperative position. In a sixth way of movement of by switching member 32 of the switching device 30 ₆ to the fourth front cam element 20 _4, as shown at (k) in FIG. 11, the end face of the front end surface of the fourth cam element 20 ₄ cam 23 will be closest in its lift end position f to the switching member 32 of the fifth switching device 30 _5, this time, switching member 32 of the fifth switching device 30 ₅ is not advanced to the operative position by malfunction or the like as was also, for the same reason as the case of the third cam element 20 _3, switching member 32 of the fifth switching device 30 ₅ is out該進is the fourth cam element 20 ₄ of the front end face of the end cam 23 does not contact, thereafter, be shifted to the fourth cam element 20 ₄ further forward by the switching member 32 of the sixth switching device 30 _6, at that time, the switching member 32 of the fifth switching device 30 ₅ already Passes lift end position f of lift part 23b And are, thus, will not be switching member 32 of the fifth switching device 30 ₅ is in contact with the end face cam 23 of the front end surface of the fourth cam element 20 _4. Thus fourth distance along the camshaft direction of the same phase between the cam surfaces of the both end face cam 23 in the cam element 20 _4, while the fourth cam element 20 ₄ sides of the switching member 32, 32 since smaller than the distance Lpin along the camshaft direction, never in any phase fourth cam element 20 ₄ becomes unrotatable caught between both sides of the switching member 32, 32.

Then, the fifth switching device 30 _5, when below its switching member 32 slope portion 23c of the fourth cam element 20 ₄ of the end face cam 23 is eliminated, it is possible to move to the switching member 32 operating position .

At this time, switching member 32 of the third switching device 30 ₃ is advanced to the opposite position of the second cam element 20 the end face of the rear end surface of the _second cam 23, in accordance with the rotation of the cam shaft 2, the third switching device 30 ₃ switching member 32, press the second cam element 20 ₂ to the front side while sliding in contact with the lift portion 23b of the second cam element 20 the end face of the rear end surface of the _second cam 23, the second cam element 20 ₂ Shift to the first predetermined position side. The second will be cam element 20 _2, it does not become unable to rotate caught between both sides of the switching member 32, 32.

Also, almost concurrently with the second shift of the cam element 20 _2, the first switching device 30 ₁ of the switching member 32, the first cam element 20 the end face of the front end surface of the _first cam 23 in a second predetermined position The advancing position advances to the facing position of the end face cam 23 during the period in which the reference face 23a is directed.

Furthermore, the position of the third switching device 30 _third switching member 32, after the lift start position e of the second cam element 20 ₂ of the end face cam 23 has reached, the camshaft 2 is rotated 90 °, the first cylinder 1 When _one of the exhaust stroke is completed, the position of the first switching device 30 ₁ of the switching member 32, the lift start position e of the first cam element 20 the front end face of the end cam 23 in ₁ reaches the rotation of the camshaft 2 according, first switching device 30 ₁ of the switching member 32 presses the first cam element 20 ₁ while sliding the lift portion 23b of the end face cam 23 rearward, the first cam element 20 ₁ first predetermined Shift to the position side. The first will be cam element 20 _1, it does not become unable to rotate caught between both sides of the switching member 32, 32.

The above operation, all the first to fourth cam elements ₂₀ 1 to 20 ₄ is shifted from the second predetermined position to the first position, as shown in FIG. 1, the first to fourth cam elements 20 ₁ 20 the first cam portion ₂₂ 1 in the operation portion 22 of the _4, 22 ₁ rocker arm C, the cam follower of the C C ', C' will return to the state that corresponds located.

As described above, according to this embodiment, four cylinders ₁ 1 to 1 ₄ 4 provided respectively on the cam elements ₂₀ 1 to 20 _4, a shift by six switching devices ₃₀ 1 to 30 _6, The cam portion that opens and closes the exhaust valve A is switched between the first cam portions 22 ₁ and 22 ₁ having a small lift amount and the second cam portions 22 ₂ and 22 ₂ having a large lift amount.

Will now be described in detail detent mechanism 40 provided a pair in each of the cam elements _{20 1 ~20 4 (40a, 40b} ). Here, an example detent mechanism 40 provided on the first cam element 20 ₁ will be described with reference to FIGS. 12 to 16.

Figure 12 is a first cam element 20 ₁ indicates when positioned in the second predetermined position, FIG. 13, the first cam element 20 ₁ is shifted to the first position from the second predetermined position A state where the first detent ball 43a has just climbed over the first top 55 is shown. FIG. 14 is an enlarged view of the periphery of the second detent cam portion 46 of FIG. Figure 15 is a first cam element 20 ₁ indicates a state located in a first predetermined position, FIG. 16, the first cam element 20 ₁ is shifted to a second predetermined position from the first predetermined position The state in the middle of being present (a state in which the second extent ball 43b has just passed over the second top portion 56) is shown.

The first groove 51 and the second groove 52 of the first detent cam portion 45 in the first detent mechanism 40 a provided on the rear side of the pair of detent mechanisms 40 are from the first top portion 55 to the bottom portions of the grooves 51 and 52. Inclined portions 51a and 52a (inclined surfaces) extending obliquely with respect to the cam shaft direction. The inclination angles of the inclined portions 51a and 52a with respect to the cam shaft direction (the inclination angle on the acute angle side) are the same and are preferably in the range of 20 ° to 30 °. In the first cam element 20 _1, the first groove 51 (the inclined portion 51a) is located on the front side of the first apex 55, the second groove 52 (the inclined portion 52a) is on the rear side of the first apex 55 To position. Note that the inclination angles of the inclined portions 51a and 52a with respect to the cam shaft direction may be different from each other.

The 1st groove | channel 51 is comprised by the side wall part of the front and back both sides formed so that a substantially V shape might be made. The rear side wall portion is the inclined portion 51a, and the front side wall portion is the inclined portion 51b inclined with respect to the cam shaft direction. Inclination angle with respect to the camshaft direction of the inclined portion 51b (acute side angle of inclination), the inclination angle with respect to the camshaft direction of the inclined portion 51a is larger than (the inclination angle of the acute angle side), the first cam element 20 ₁ when the second predetermined position of the first shift to a predetermined position, the inclined portion 54b and the cooperation of the described in the fourth groove 54, first to stop the cam element 20 ₁ in a first predetermined position Has been made. That is, the inclined portion 51b of the first groove 51 (corresponding to the side wall portion of the other side of the first groove 51), and the inclined portion 54b of the fourth groove 54 has a first side after the cam element 20 ₁ (one side ) Constitutes a regulation section that regulates the shift to.

Similarly to the first groove 51, the second groove 52 is also composed of side wall portions on both the front and rear sides formed so as to be substantially V-shaped. The front side wall portion is the inclined portion 52a, and the rear side wall portion is the inclined portion 52b inclined with respect to the cam shaft direction. Inclination angle with respect to the camshaft direction of the inclined portion 52 b (acute side angle of inclination), the inclination angle with respect to the camshaft direction of the inclined portion 52a is larger than (the inclination angle of the acute angle side), the first cam element 20 ₁ when the first predetermined position of the shift to the second predetermined position, the inclined portion 53b and the cooperation of the described in the third groove 53, the first cam element 20 ₁ to stop at a second predetermined position Has been made. The inclined portion 52b of the second groove 52 and, the inclined portions 53b of the third groove 53 constitutes a regulating portion for regulating a shift to the first cam element 20 ₁ of the front side (the other side).

Further, up to the first detent ball 43a in a state of fitted into the first groove 51 rides over the first apex 55 from the state, along the cam axis relative to the first cam element 20 ₁ of the first detent ball 43a relative moving distance, to the first detent ball 43a of fitting waiting state to the second groove 52 rides over the first apex 55 from the state, the first cam relative to the cam element 20 ₁ of the first detent ball 43a It is longer than the relative movement distance along the axial direction. That is, the distance d1 along the cam shaft direction between the center of the first detent ball 43a fitted in the first groove 51 and the first top 55 is the first in the state fitted in the second groove 52. It is set longer than the distance d2 along the cam shaft direction between the center of the detent ball 43a and the first top 55. The sum of the distance d1 and the distance d2 is a distance d0 between the first predetermined position and the second predetermined position. The distance d1 is longer than d0 / 2, and the distance d2 is d0. Shorter than / 2. In the present embodiment, since the inclination angles of the inclined portions 51 a and 52 a with respect to the cam shaft direction are the same, the depth of the first groove 51 with respect to the first top portion 55 is the depth of the second groove 52 with respect to the first top portion 55. The position of the first detent ball 43a in the state where the first detent ball 43a is fitted in the first groove 51 is larger than the position of the first detent ball 43a in the state where the first detent ball 43a is fitted in the second groove 52. 2 radially outside. Regarding the relative movement distance and the distances d1 and d2, the state in which the first detent ball 43a is fitted in the first groove 51 (or the second groove 52) means that the first detent ball 43a is in the first groove 51 ( Or it is the state (completely fitted state) located in the bottom part side most in the 2nd groove | channel 52).

The third groove 53 and the fourth groove 54 of the second detent cam portion 46 in the second detent mechanism 40 b provided on the front side of the pair of detent mechanisms 40 are formed from the second top portion 56 to the bottom portions of the grooves 53 and 54. Inclined portions 53a and 54a (inclined surfaces) extending obliquely with respect to the camshaft direction are provided. The inclination angles (inclination angles on the acute angle side) of these inclined portions 53a and 54a with respect to the cam shaft direction are the same and are preferably in the range of 20 ° to 30 °. In the first cam element 20 _1, the third groove 53 (the inclined portion 53a) is located on the rear side of the second apex portion 56, a fourth groove 54 (the inclined portion 54a) is in front of the second apex portion 56 To position. The inclination angles of the inclined portions 53a and 54a with respect to the cam shaft direction may be different from each other.

The third groove 53 is composed of side wall portions on both the front and rear sides formed so as to be substantially V-shaped. The front side wall portion is the inclined portion 53a, and the rear side wall portion is the inclined portion 53b inclined with respect to the cam shaft direction. The inclination angle (acute angle on the acute angle side) of the inclined portion 53b with respect to the cam axis direction is made larger than the inclination angle (the acute angle on the acute angle side) of the inclined portion 53a with respect to the cam axis direction, as described above. during the shift from the first predetermined position of the cam element 20 ₁ to the second predetermined position, the inclined portion 52b and the cooperation of the second groove 52, first stop cam element 20 ₁ in the second predetermined position It is made to let you.

Similarly to the third groove 53, the fourth groove 54 is constituted by side wall portions on both front and rear sides formed so as to be substantially V-shaped. The rear side wall portion is the inclined portion 54a, and the front side wall portion is the inclined portion 54b that is inclined with respect to the cam shaft direction. The inclination angle (acute angle on the acute angle side) of the inclined portion 54b with respect to the cam axis direction is made larger than the inclination angle (the acute angle on the acute angle side) of the inclined portion 54a with respect to the cam axis direction, as described above. during the shift from the second predetermined position of the cam element 20 ₁ to the first predetermined position, the inclined portion 51b and the cooperation of the first groove 51, the first stop cam element 20 ₁ in a first predetermined position It is made to let you.

Also, until the second detent ball 43b in a state of fitted into the third groove 53 goes over the second apex 56 from the state, along the cam axis relative to the first cam element 20 ₁ of the second detent ball 43b relative moving distance, to the second detent ball 43b in a state of fitted into the fourth groove 54 goes over the second apex 56 from the state, the first cam relative to the cam element 20 ₁ of the first detent ball 43b It is longer than the relative movement distance along the axial direction. That is, the distance d3 along the cam shaft direction between the center of the second detent ball 43b fitted in the third groove 53 and the second top portion 56 is the second in the state fitted in the fourth groove 54. The distance d4 is set longer than the distance d4 along the cam shaft direction between the center of the detent ball 43b and the second top portion 56. The sum of the distance d3 and the distance d4 is a distance d0 between the first predetermined position and the second predetermined position. The distance d3 is longer than d0 / 2, and the distance d4 is d0. Shorter than / 2. In the present embodiment, since the inclination angles of the inclined portions 53 a and 54 a with respect to the cam shaft direction are the same, the depth of the third groove 53 with respect to the second top portion 56 is the depth of the fourth groove 54 with respect to the second top portion 56. The position of the second detent ball 43b in the state of being fitted in the third groove 53 is larger than that of the position of the second detent ball 43b in the state of being fitted in the fourth groove 54. 2 radially outside. Regarding the relative movement distance and the distances d3 and d4, the state in which the second detent ball 43b is fitted in the third groove 53 (or the fourth groove 54) means that the second detent ball 43b is in the third groove 53 ( Or it is the state (completely fitted state) located on the most bottom side in the fourth groove 54).

  In the present embodiment, the first detent cam portion 45 (first groove 51, second groove 52 and first top portion 55) and second detent cam portion 46 (third groove 53, fourth groove 54 and second top portion 56). Is formed symmetrically with respect to a plane that passes through the center in the cam shaft direction between the first top portion 55 and the second top portion 56 and is perpendicular to the cam shaft direction. The diameter of the second detent ball 43b is the same as the diameter of the first detent ball 43a. Therefore, the distance d3 is the same as the distance d1, and the distance d4 is the same as the distance d2. Therefore, the distance d3 is longer than the distance d2, and the distance d1 is longer than the distance d4. become longer. The first detent cam portion 45 and the second detent cam portion 46 are not necessarily symmetrical with respect to the plane. For example, the diameter of the second detent ball 43b is different from the diameter of the first detent ball 43a. In some cases, it is usually not symmetrical.

The first and second detent mechanisms 40a, 40b, as shown in FIG. 12, when _{the 1} first cam element 20 is positioned in the second predetermined position, the first detent ball 43a is fitted in the second groove 52 Mari and in a state in which the second detent ball 43b is fitted in the third groove 53, when the first cam element 20 ₁ is shifted into the one side of the cam shaft direction from the second predetermined position (rear side) The first detent ball 43 a moves relatively to the first top 55 side along the inclined portion 52 a of the second groove 52, and the second detent ball 43 b relatively moves along the inclined portion 53 a of the third groove 53. When the first detent ball 43a moves over the first top 55 as shown in FIG. 13 because the distance d3 is longer than the distance d2, the second detent ball 43b moves to the second top 56 side. Is second The parts 56 are moving, by the first detent ball 43a presses the inclined portion 51a of the first groove 51 after overcoming the above, a shift to the first cam element 20 ₁ of the one side (rear side) It is comprised so that it can assist.

Here, when the second detent ball 43b is moving on the second top portion 56, as shown in FIG. 14, on the movement locus (indicated by a one-dot chain line) of the center P of the second detent ball 43b, This is when the center P of the two detent balls 43 b is located within a range S on the arc centered on the second top 56. When the center P of the second detent ball 43b is located within the range S, the direction in which the second detent ball 43b presses the second detent cam portion 46 is not fixed, and the second detent ball 43b is in the first cam. Causes of resistance shift to the rear side of the elements 20 _1, clearly the indeterminate whether to contribute to assist. Even if resistance is provided, the resistance force is considerably smaller than when the second detent ball 43 b is moved relatively to the second top 56 side along the inclined portion 53 a of the third groove 53. When the center P of the second detent ball 43b enters the range S from the third groove 53 or the fourth groove 54 and exits to the opposite side, the second detent ball 43b has climbed over the second top 56. become. The relationship between the first detent ball 43a and the first top 55 is the same. The distances d2 and d3 are set so that the second detent ball 43b is moving on the second top 56 when the first detent ball 43a gets over the first top 55.

When the second detent ball 43b is moving on the second top portion 56, the first detent ball 43a is already over the first top portion 55, and by pressing the inclined portion 51a of the first groove 51, since one assist a shift to the rear side of the cam element 20 _1, since overcome above by first switching member 30 ₁ a first cam element 20 ₁ is not pushed rearward, the cam by the assist element 20 ₁ is positioned at the first predetermined position. Here, the resistance force of the second detent ball 43b moving on the second top portion 56 is considerably small as described above, and the assist force by the first detent ball 43a is larger than the resistance force, and the assist force is increased. shifted to the first cam element 20 ₁ is a rear side by the force, eventually also the second detent ball 43b over the second top portion 56, if so, even the second detent ball 43b of the first cam element 20 ₁ It will be to assist the shifting to the rear side, the first cam element 20 ₁ will be positioned reliably the first predetermined position.

The first and second detent mechanisms 40a, 40b, as shown in FIG. 15, when the first cam element 20 ₁ is located at the first predetermined position, the first detent ball 43a is in the first groove 51 fits and second detent ball 43b is in fitted wait state to the fourth groove 54, when the first cam element 20 ₁ is shifted from the first predetermined position to the other side of the cam shaft direction (front side) The first detent ball 43 a moves relatively to the first top 55 side along the inclined portion 51 a of the first groove 51, and the second detent ball 43 b relatively moves along the inclined portion 54 a of the fourth groove 54. When the second detent ball 43b gets over the second top 56 as shown in FIG. 16, the distance d1 is longer than the distance d4, so that the first detent ball is moved to the second top 56 side. 43a A moving the first apex 55, that the second detent ball 43b presses the inclined portion 53a of the third groove 53 after overcoming the above, to the first cam element 20 ₁ of the other side (front side) The shift is assisted. The distances d1 and d4 are set so that the first detent ball 43a is moving on the first top 55 when the second detent ball 43b gets over the second top 56 (in this embodiment, d1 = D3, d4 = d2).

When the first detent ball 43a is moving on the first top portion 55, the second detent ball 43b is already over the second top portion 56, and by pressing the inclined portion 53a of the third groove 53, since assist one shift to the front of the cam element 20 _1, the overcoming thereafter, by the second switching member 30 ₂ first cam element 20 ₁ is not pushed to the front, cam element by the assist 20 ₁ is positioned at the second predetermined position.

If the distances d1, d2, d3, and d4 are all the same, the distances d1, d2, d3, and d4 are all d0 / 2. In this case, the first switching member 30 ₁ or the second switching member 30 _2, the first cam element 20 ₁ at least d0 / 2 + alpha (overcoming min) is required to press only. In contrast, in the present embodiment, when the first cam element 20 ₁ is shifted rearward from the second predetermined position, the first switching member 30 _1, the fitting waiting state to the second groove 52 the amount of only the first detent ball 43a rides over the first apex 55, i.e. d2 (<d0 / 2) + α may be pressed only when the first cam element 20 ₁ is shifted to the front side from the first predetermined position the second switching member 30 _2, the amount of the second detent ball 43b in a state in which fitting waited a fourth groove 54 only cosyl take the second apex 56, i.e. d4 pressing only (<d0 / 2) + α Good. As a result, the first and second switching member ₃₀ 1, 30 ₂ first can reduce the pressing amount of the cam element 20 ₁ by, in other words, the end surface of both end faces of the first cam element 20 _first cam 23 , 23 can be lowered. In addition, even if the distances d1, d2, d3, and d4 are all the same, the assembly method of the valve gear described below can be applied.

Then, assembling method of the valve train, i.e. a method of assembling the cam shaft 2 of each cam elements ₂₀ 1 to 20 _4, in the first example cam element 20 _1, based on 17 to 20 I will explain.

In the present embodiment, the first and second cam elements ₂₀ 1, 20 _2, inserted from the front end of the cam shaft 2, the third and fourth cam elements ₂₀ 1, 20 _2, the camshaft 2 Insert from the rear edge. Therefore, from the front end of the cam shaft 2, the second insert the cam element 20 ₂ first, then, to first insert the cam element 20 _1. From the side of the end after the cam shaft 2, the third cam element 20 ₃ is inserted first, then, to insert the fourth cam element 20 _4. For example, all of the first to fourth cam element portions 20 _{1 to} 20 ₄ may be inserted from the front or rear end of the cam shaft 2.

In the present embodiment, by moving rearward the first cam element 20 ₁ by inserting the end first cam element 20 ₁ from the front of the cam shaft 2 to the cam shaft 2, the first cam element the parts 20 ₁ assembled to the cam shaft 2. At that time, the second detent ball 43 b needs to pass through the first detent cam portion 45 and reach the position of the second detent cam portion 46. When the second detent ball 43b passes through the first Ditentokamu portion 45, but will pass through the inclined portion 51b of the first groove 51, the inclined portion 51, as described above, the first cam element 20 ₁ after to configure the regulating portion for regulating a shift to the side, is larger inclination angle relative to the cam axis (acute side angle of inclination) is, from this, first the rear of cam element 20 ₁ side The second detent ball 43b is caught by the inclined portion 51b even if it is moved to the position, and as a result, it is not easy for the second detent ball 43b to pass through the inclined portion 51b. In particular, in the present embodiment, as described above, since the depth of the first groove 51 is deep, when the second detent ball 43b is fitted into the first groove 51, the second detent ball 43b is inserted into the second hole 41b. The amount of the second detent ball 43b is more easily caught by the inclined portion 51b.

  Therefore, when the second detent ball 43 b passes through the inclined portion 51 b of the first groove 51, the second detent ball 43 b is pushed by the pusher 71 protruding from the bottom of the first groove 51 into the first groove 51. Is pressed toward the second hole 41b.

Therefore, in the present embodiment, as shown in FIG. 17, prior to insertion of the first cam element 20 ₁ to the camshaft 2, previously mounted in advance first cam element 20 ₁ in the pusher 71. The pusher 71 has a mounting portion 72 which is mounted on the step portion 25 so as to surround the entire periphery of the stepped portion 25 of the rear side of the first cam element 20 _1. The mounting portion 72 has a split structure including two halves 72a and 72b, and these two halves 72a and 72b are detachably coupled (for example, by screws). Coupling, snap coupling, etc.). Then, when the mounting portion 72 is attached to the stepped portion 25, the halved portions 72a and 72b are coupled to each other, thereby mounting the mounting portion 72 on the stepped portion 25.

  When the mounting portion 72 is mounted on the rear stepped portion 25 on the inner surface of one of the two halved portions 72a and 72b (in the present embodiment, the halved portion 72a) of the mounting portion 72, A rod-like member 73 that presses the second detent ball 43b located in the first groove 51 toward the second hole 41b is integrally provided.

The first cam element 20 _1, the first cam element 20 ₁ in the pusher 71 (mounting portion 72) when mounted, the through-holes 26 in which the rod member 73 is inserted is formed. The through-hole 26 opens at one location in the circumferential direction of the outer peripheral surface of the rear step portion 25 (a location corresponding to the second detent ball 43 b), and is the _{first on} the inner peripheral surface of the first cam element portion 201. An opening is formed at the bottom of one groove 51. Bottom of the first groove 51, since the displacement in the direction along the cam shaft and the stepped portion 25 of the rear through-hole 26 is inclined rearward toward the first radially inside the cam element 20 ₁ It extends.

Rod-like member 73 of the pusher 71, when the first cam element 20 ₁ in the pusher 71 (mounting portion 72) is mounted, the first length such as to protrude from the groove bottom side of the opening of the through hole 26 Is formed. Therefore, when the second detent ball 43b is positioned in the first groove 51, the rod-like member 73 of the pusher 71 presses the second detent ball 43b toward the second hole 41b.

The rear side of the first Ditentokamu portion 45 in the first inner peripheral surface of the cam element 20 ₁ (the rear side of the inclined portion 52b of the second groove 52) to the first cam element 20 ₁ of the cam shaft 2 A rear inclined portion 27 is formed to smoothly guide the first and second detent balls 43a and 43b to the first detent cam portion 45 side during assembly.

To assemble the first cam element 20 ₁ to the cam shaft 2, first, attached to the stepped portion 25 of the rear side of the first cam element 20 ₁ the mounting portion 72 of the pusher 71. At this time, the rod-shaped member 73 is inserted into the through hole 26.

  Subsequently, the second spring 42b and the second detent ball 43b are set in the second hole 41b. At this time, the first spring 42a and the first detent ball 43a may be set in the first hole 41a. However, in this embodiment, the second detent ball 43b is inclined by the inclined portion 51b of the first groove 51. After passing through.

After the set of the second spring 42b and a second detent balls 43 b, as shown in FIG. 18, the first cam element 20 ₁ fitted with the pusher 71, the front side of the cam shaft 2 (first cam element 20 insert from the end of the "other side") for _1, to move the first cam element 20 ₁ to back of the cam shaft 2 side (the "one side").

Shortly after the movement, the second detent ball 43b abuts the rear inclined portion 27 (see FIG. 18), by the rear inclined portion 27, as the movement in the first rear side of the cam element 20 _1, the second The detent ball 43 b is pressed toward the second hole 41 b, and the second detent ball 43 b is fitted into the second groove 52 before long.

Moving to the first cam element 20 ₁ further rear, as shown in FIG. 19, the second detent ball 43b reaches the position of the first groove 51 rides over the first apex 55. Since the rod-shaped member 73 projects into the first groove 51 from the bottom of the first groove 51, the second detent ball 43b is pressed toward the second hole 41b. As a result, by moving the first cam element 20 ₁ further rear, the second detent ball 43b easily passes through the inclined portion 52b of the second groove 52.

Then, moving to the first cam element 20 ₁ further rear, second detent ball 43b is directed to the side of the second Ditentokamu portion 46 while in contact with the portion to be spline-fitted with the cam shaft 2.

Before the first front end of the cam element 20 ₁ even after the second detent ball 43b is passed through the inclined portion 52b reaches the first hole 41a, the first hole 41a, the first spring 42a and the first detent ball 43a is set.

Then, moving to the first cam element 20 ₁ further rear, as shown in FIG. 20, the first detent ball 43a abuts the rear inclined portion 27, by the rear inclined portion 27, the first cam element As the rearward movement of part 20 _1, the first detent ball 43b is pressed against the first hole 41b side, eventually, the first detent ball 43a is fitted into the second groove 52. The second detent ball 43b fits into the third groove 53 substantially simultaneously with the fitting of the first detent ball 43a into the second groove 52 (see FIG. 12). Thus assembly of the first to the cam element 20 ₁ of the cam shaft 2 is completed. Incidentally, the first cam element 20 ₁ is further moved to the rear, fitted with a first detent ball 43a in the first groove 51 may be the second detent ball 43b to fit into the fourth groove 54.

As described above, when the second detent ball 43 b passes through the inclined portion 51 b of the first groove 51, the second detent ball is pushed by the pressing tool 71 (rod-like member 73) that protrudes from the bottom of the first groove 51. because pressing the 43b to the second hole 41b side, without the second detent ball 43b is caught by the inclined portion 51b, the inclined portion 51b easily passes, the result, the first cam element relative to the cam shaft 2 20 ₁ Assembling performance is improved.

After assembly of the first cam element 20 ₁ of the cam shaft 2, remove the pusher 71 from the first cam element 20 _1. Thereby, although the said through-hole 26 will be in the open state, it will not block | close this. That is, the through-hole 26 becomes a first lubricating oil supply hole to the inside of the cam element 20 _1, the lubricating oil supplied to the outer circumferential surface of the first cam element 20 ₁ by the oil shower, via a through-hole 26 Te, and the spline fitting portion between the cam shaft 2 and the first cam element 20 _1, will be better fed to a pair of detent mechanism 40.

In the present embodiment, so as to mount the pusher 71 to the first cam element 20 _1, this is not limited, for example, when the second detent ball 43b is positioned in the first groove 51 The operator may hold the pusher 71 and press the second detent ball 43b toward the second hole 41b.

Here, the through hole 26, if those that open to the outer peripheral surface of the stepped portion 25 of the rear and the bottom of the first groove 51 first at cam element 20 ₁ formed only one, as described above , the assembly of the first cam element 20 ₁ of the cam shaft 2 can be easily, but in the present embodiment, as can be easily performed first removal of the cam element 20 ₁ from the cam shaft 2, the 1 cam element 20 another alternative through hole 28 to ₁ is also formed. The through-hole 28, in the first cam element 20 ₁ be open to the outer peripheral surface of the front step part 25 and the bottom of the third groove 53, a first inward in the radial direction of the cam element 20 ₁ Inclined to the front side.

When removing the first cam element 20 ₁ from the cam shaft 2, as shown in FIG. 21, for mounting the mounting portion 72 of the pusher 71 on the front side of the step portion 25 of the first cam element 20 _1. At this time, the rod-shaped member 73 is inserted into the through hole 28. When mounting the pusher 71, the first cam element 20 ₁ may be positioned in the first predetermined position, it may be positioned in the second predetermined position.

After mounting of the pusher 71 moves the first cam element 20 ₁ to the front side. Accordingly, the first cam element 20 ₁ at the time of attachment of the pusher 71 when located in a first predetermined position, the first cam element 20 ₁ is located at the second predetermined position. At this time, since the rod-like member 73 of the pusher 71 protrudes from the bottom of the third groove 53 into the third groove 53, the second detent ball 43b easily passes without being caught by the inclined portion 53b of the third groove 53. To do.

On the other hand, the first detent ball 43a is caught by the inclined portion 52b of the second groove 52. In the present embodiment, since the depth of the second groove 52 is shallow, the first cam element portion 20 is relatively strong. _{If 1} is moved to the front side, the first detent ball 43a passes through the inclined portion 52b and moves to the rear inclined portion 27 side.

Is moved to the first cam element 20 ₁ further front in turn, the second detent ball 43b is caught by the inclined portion 52b of the second groove 52, also in this case, the first cam element with a relatively strong force by moving the parts 20 ₁ to the front side, the second detent ball 43b is moved to the side of the rear inclined portion 27 through the inclined portion 52b.

Thus it is possible to perform the first removal of the cam element 20 ₁ from the cam shaft 2. In other words, when the valve operating device fails and the serviceman repairs it, if the cam element is defective, it is only necessary to replace the defective cam element without replacing the entire valve operating device. Become. The through-holes 28, like the through-hole 26, becomes the first lubricating oil supply hole to the inside of the cam element 20 _1, the lubricating oil, via the through-holes 26, 28, the cam shaft 2 and the first against the spline fitting portion and a pair of detent mechanism 40 of the cam element 20 _1, so that more can be better supplied.

In the present embodiment, the first cam element 20 _1, the front side of the cam shaft 2 (for the first cam element 20 ₁ "other side") was inserted from the end of the first cam element 20 ₁ was to move to the rear side of the cam shaft 2 (the "one side"), the first cam element 20 _1, "one side" of the side (first cam element 20 ₁ after the cam shaft 2 insert the end of) the first cam element 20 ₁ by moving to the front side of the cam shaft 2 (the "other side"), it can also be assembled the first cam element 20 ₁ to the camshaft 2 It is.

In this case, prior to insertion of the first cam element 20 ₁ to the cam shaft 2, as in the case of the first detachment of the cam element 20 ₁ from the cam shaft 2, the mounting portion 72 of the pusher 71 the 1 is mounted on the front side of the step portion 25 of the cam element 20 _1, this time, to insert the rod-like member 73 into the through hole 28.

Subsequently, the first hole 41a, and set the first spring 42a and the first detent ball 43a, then, the first cam element 20 ₁ fitted with the pusher 71, from the side of the end after the camshaft 2 inserted, to move the first cam element 20 ₁ to the front side of the cam shaft 2.

Shortly after the movement, the front inclined second detent ball 43b is formed on the front side of the second Ditentokamu portion 46 in the first inner peripheral surface of the cam element 20 ₁ (front side of the inclined portion 54b of the fourth groove 52) contact with the part 29, by the front inclined portion 29, as the movement in the first front side of the cam element 20 _1, the first detent ball 43a is pressed against the first hole 41a side, eventually, the first detent The ball 43a fits into the fourth groove 54.

It is further moved to the front side of the first cam element 20 _1, as shown in FIG. 22, the first detent ball 43a reaches the position of the third groove 53 rides over the second apex 56. Since the rod-like member 73 protrudes into the third groove 53 from the bottom of the third groove 53, the first detent ball 43a is pressed toward the first hole 41a. As a result, by moving the first cam element 20 ₁ further front, first detent ball 43a is easily pass through the inclined portion 53b of the third groove 53.

Then, moving to the first cam element 20 ₁ further front, first detent ball 43a is directed toward the first Ditentokamu portion 45 while in contact with the portion to be spline-fitted with the cam shaft 2.

Before the first trailing edge of the cam element 20 ₁ even after the first detent ball 43a has passed the inclined portion 53b reaches the second hole 41b, the second hole 41b, the second spring 42b and a second detent set the ball 43 b, then, is moved to the first cam element 20 ₁ further front, eventually, together with the second detent ball 43a is fitted into the fourth groove 54, the first detent ball 43a is first groove 51 Will fit in. Thus assembly of the first to the cam element 20 ₁ of the cam shaft 2 is completed. Incidentally, the first cam element 20 ₁ further moves to the front side, fitted with a first detent ball 43a to the second groove 52 may be the second detent ball 43b to fit into the third groove 53.

Thus the first cam element 20 _1, may be inserted from the side of the end after the cam shaft 2, without first detent ball 43a is caught by the inclined portion 53b of the third groove 53, the inclined portion 53b readily cross, as in the case of insertion from the front end of the cam shaft 2, the first assembly of the cam element 20 ₁ relative to the cam shaft 2 is improved.

Assembled to the cam shaft 2 of the other cam element ₂₀ 2 to 20 ₄ is also the same as the first cam element 20 _1. For example, if the second cam element 20 _2, in the present embodiment, the second cam element 20 ₂ is inserted from the end of the front of the camshaft 2 ( "one side" of the second cam element 20 ₂ with it) , the second cam element 20 ₁ by moving to the rear side of the cam shaft 2 (the "other side"), mounting the second cam element 20 ₂ in the camshaft 2. If the second cam element 20 _2, there is a first detent mechanism 40a to the front, there is a second detent mechanism 40b on the rear side (see FIG. 3). Then, when assembling the second cam element 20 ₂ to the camshaft 2, the second cam element 20 the outer peripheral surface of the stepped portion 25 of the rear in the ₂ and the through hole 28 which opens in the bottom of the third groove 53 (FIG. 3 in not visible), as the rod-shaped member 73 of the pusher 71 is inserted, the mounting portion 72 of the pusher 71, the second may be mounted on the stepped portion 25 of the rear side of the cam element 20 ₂ . Then, by moving the second cam element 20 ₂ by inserting the second cam element 20 ₂ to the cam shaft 2 from the front end of the camshaft 2 to the rear side of the camshaft direction, The second detent ball 43 b is fitted into the fourth groove 54, and the first detent ball 43 a is fitted into the first groove 51 through the inclined portion 53 b of the third groove 53. When the first detent ball 43 a passes through the inclined portion 53 b of the third groove 53, the first detent ball 43 a is pressed toward the first hole 41 a by the rod-like member 73 of the pusher 71. 43a easily passes through the inclined portion 53b without being caught by the inclined portion 53b.

  The present invention is not limited to the embodiment described above, and can be substituted without departing from the spirit of the claims.

For example, in the above embodiment, the through-hole 26, extends inclined rearward toward the first radially inside the cam element 20 _1, the through hole 28 is first radially inner cam element 20 ₁ Although extends inclined to the front towards the, as shown in FIG. 23, through holes 26, 28 may be extended straight to the first radial direction of the cam element 20 _1. That is, the reason why the through holes 26 and 28 are inclined and extended as in the above embodiment is that the through holes 26 and 28 do not open to the operating portion 22 (the first cam portion 22 ₁ or the second cam portion 22 ₂ ). It is for doing so. However, when the through holes 26, 28 extends inclined, results in the rod-shaped member 73 extends obliquely from the inside of the half portion 72a of the mounting portion 72, the pusher 71 to the first cam element 20 ₁ When mounting, it becomes difficult to insert the rod-like member 73 into the through hole 26 or the through hole 28, and the first detent ball 43a or the second detent ball 43b is pressed straight against the first hole 41a or the second hole 41b. become unable. Therefore, in order to prevent such a problem, the through-holes 26, 28, so as to extend straight in a first radial direction of the cam element 20 _1. In this case, although the through-holes 26, 28 is opened to the working portion 22 (first cam part 22 ₁ or the second cam section 22 _2), opening to the base circle a to avoid the nose portion _b 1, _{b 2} By doing so, there is no problem in opening and closing the exhaust valve.

  The above-described embodiments are merely examples, and the scope of the present invention should not be interpreted in a limited manner. The scope of the present invention is defined by the scope of the claims, and all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention includes a cylindrical cam element portion that is coupled to a cam shaft in a rotational direction and is fitted so as to be capable of shifting (moving) in the cam shaft direction and has two cam portions for opening and closing the valve. In the valve operating apparatus for an engine, wherein the cam portion for opening and closing the valve is switched between the two valve opening and closing cam portions by shifting the element portion to one side or the other side in the cam shaft direction. This is useful when the element portion is assembled to the camshaft.

2 cam shafts 20 _{1 to} 20 ₄ cam element portions 22 ₁ , 22 ₂ valve opening / closing cam portions 23 end face cams (first end face cam, second end face cam)
32 switching member (first switching member, second switching member)
40 Detent mechanism 43a First detent ball (first pressing member)
43b Second detent ball (second pressing member)
45 1st detent cam part 46 2nd detent cam part 51 1st groove | channel 51a Inclination part (regulation part) of 1st groove | channel
52 2nd groove 52a 2nd groove inclination part 53 3rd groove 53a 3rd groove inclination part (regulation part)
54 4th groove 54a 4th groove inclination part 55 1st top part 56 2nd top part 71 Pusher

Claims (3)

A cylindrical cam element portion that is coupled to the cam shaft in the rotational direction and is slidably fitted in the cam shaft direction and has two valve opening and closing cam portions, and the cam element portion in the cam shaft direction is provided. In a valve operating apparatus for an engine in which a cam portion for opening and closing a valve is switched between the two valve opening and closing cam portions by shifting to one side or the other side, the cam element portion is used as the cam shaft. A method for assembling an engine valve device,
When the cam element portion is shifted to one side in the cam shaft direction, the valve operating device holds the cam element portion at the first predetermined position, and when the cam element portion is shifted to the other side in the cam shaft direction. A detent mechanism provided as a pair with respect to a single cam element portion for holding the cam element portion at a second predetermined position located on the other side of the first predetermined position;
One of the pair of detent mechanisms is located in a first detent cam portion provided on the inner peripheral surface of the cam element portion and partly in a first hole formed in the cam shaft. And a first pressing member pressed by the first elastic member on the first detent cam portion,
The other detent mechanism includes a second detent cam portion provided on the inner peripheral surface of the cam element portion, and a part thereof is located in a second hole formed in the cam shaft. A second pressing member pressed by the second elastic member, and located on the other side in the camshaft direction from the one detent mechanism,
The first detent cam portion includes a first groove into which the first pressing member is fitted when the cam element portion is located at the first predetermined position, and the one side in the cam shaft direction with respect to the first groove. And a second groove into which the first pressing member is fitted when the cam element portion is located at the second predetermined position,
The second detent cam portion includes a third groove into which the second pressing member is fitted when the cam element portion is located at the second predetermined position, and the other side in the cam shaft direction with respect to the third groove. And a fourth groove into which the second pressing member is fitted when the cam element portion is located at the first predetermined position.
The side wall portion on the other side of the first groove constitutes a restricting portion that restricts the shift of the cam element portion to the one side,
A first setting step of setting the first elastic member and the first pressing member in the first hole;
A second setting step of setting the second elastic member and the second pressing member in the second hole;
By inserting the cam element portion into the cam shaft from the other end of the cam shaft and moving the cam element portion to the one side, the first pressing member set in the first setting step is moved. And a cam element part assembling step for fitting the second pressing member set in the second setting step into the third groove by passing the second pressing member set in the second setting step through the regulating portion of the first groove,
In the cam element portion assembly step, when the second pressing member passes through the restriction portion of the first groove, the second pressing member is moved by the pressing tool protruded from the bottom portion of the first groove. A method for assembling the valve gear for an engine, characterized by pressing toward the two holes. A cylindrical cam element portion that is coupled to the cam shaft in the rotational direction and is slidably fitted in the cam shaft direction and has two valve opening and closing cam portions, and the cam element portion in the cam shaft direction is provided. In a valve operating apparatus for an engine in which a cam portion for opening and closing a valve is switched between the two valve opening and closing cam portions by shifting to one side or the other side, the cam element portion is used as the cam shaft. A method for assembling an engine valve device,
When the cam element portion is shifted to one side in the cam shaft direction, the valve operating device holds the cam element portion at the first predetermined position, and when the cam element portion is shifted to the other side in the cam shaft direction. A detent mechanism provided as a pair with respect to a single cam element portion for holding the cam element portion at a second predetermined position located on the other side of the first predetermined position;
One of the pair of detent mechanisms is located in a first detent cam portion provided on the inner peripheral surface of the cam element portion and partly in a first hole formed in the cam shaft. And a first pressing member pressed by the first elastic member on the first detent cam portion,
The other detent mechanism includes a second detent cam portion provided on the inner peripheral surface of the cam element portion, and a part thereof is located in a second hole formed in the cam shaft. A second pressing member pressed by the second elastic member, and located on the other side in the camshaft direction from the one detent mechanism,
The first detent cam portion includes a first groove into which the first pressing member is fitted when the cam element portion is located at the first predetermined position, and the one side in the cam shaft direction with respect to the first groove. And a second groove into which the first pressing member is fitted when the cam element portion is located at the second predetermined position,
The second detent cam portion includes a third groove into which the second pressing member is fitted when the cam element portion is located at the second predetermined position, and the other side in the cam shaft direction with respect to the third groove. And a fourth groove into which the second pressing member is fitted when the cam element portion is located at the first predetermined position.
The one side wall portion of the third groove constitutes a restricting portion that restricts the shift of the cam element portion to the other side,
A first setting step of setting the first elastic member and the first pressing member in the first hole;
A second setting step of setting the second elastic member and the second pressing member in the second hole;
By inserting the cam element portion into the cam shaft from the one end of the cam shaft and moving the cam element portion to the other side in the cam shaft direction, the second set step is set. A cam element part assembling step for fitting the second pressing member into the fourth groove and fitting the first pressing member set in the first setting step into the first groove by passing the regulating portion of the third groove; With
In the cam element part assembly step, when the first pressing member passes through the restriction portion of the third groove, the first pressing member is moved by the pressing tool protruding from the bottom of the third groove. A method for assembling the valve gear for an engine, wherein the valve is pressed toward one hole. The method for assembling the valve gear for an engine according to claim 1 or 2,
Attaching the pusher to the cam element portion before the cam element portion assembling step;
And a step of removing the pusher from the cam element portion after completion of the cam element portion assembling step.