JP6676971B2 - Valve train - Google Patents

Description

  The present invention relates to a valve gear for driving a valve body of an engine to open and close.

  2. Description of the Related Art Conventionally, there has been known a valve mechanism that reciprocates an engine valve body by converting a rotational motion of a camshaft into a rocking motion of a rocker arm. A variety of power transmission members (rotating members, oscillating members, reciprocating members, etc.) for amplifying the oscillation generated by the cam fixed to the camshaft and transmitting the amplified power to the valve body are provided inside the valve operating mechanism. ) Is built-in. There is also known a variable valve mechanism that controls the reciprocating amount (valve lift) and phase (valve timing) of a valve body in multiple stages by switching the operation state of a plurality of power transmission members. In recent years, a continuously variable valve mechanism capable of arbitrarily adjusting a valve lift and a valve timing by continuously changing a positional relationship and a contact position between power transmission members has been developed (see Patent Document 1).

JP 2008-215103 A

  Generally, among various rocking members (rocker arms) provided in a valve operating mechanism, an intake rocker arm for driving an intake valve and an exhaust rocker arm for driving an exhaust valve are provided with shafts such as an intake rocker shaft and an exhaust rocker shaft. It is mounted so as to be swingable with respect to the shaped member. However, the other rocker arms are not necessarily mounted around the shaft-shaped member, and may be attached via, for example, a pin member connected to the shaft member. The valve operating mechanism having such a structure has a problem in that the position of the link member may move in the assembling process or the link member may come off from the shaft-shaped member, and it is difficult to obtain good workability.

  In the example shown in Patent Document 1, a control arm is rotatably attached to one end of a center rocker arm via a connecting pin, and the control arm is locked to the intake rocker arm. The locked state between the control arm and the intake rocker arm is in a non-fastened state so that the position of the connecting pin can be finely adjusted. After the valve mechanism is completely assembled, the center rocker arm is sandwiched between the cam fixed to the camshaft and another power transmission member. Therefore, the control arm does not move during operation of the engine.

  However, when the valve mechanism is not completely assembled, such as during the process of assembling the engine or performing maintenance work on the valve mechanism, the control arm may move in the extending direction. Therefore, the operator must perform the assembling work while paying attention so that the control arm does not fall off the intake rocker arm.

  One of the objects of the present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a valve train capable of improving assembling workability with a simple configuration. It is to be noted that the present invention is not limited to this object, and is an operation and effect derived from each configuration shown in “Embodiments for carrying out the invention” described later, and it is possible to obtain an operation and effect that cannot be obtained by the conventional technology. Can be positioned as an objective.

(1) The valve train disclosed herein has a shaft-like pivot rotatably connected to a rocker arm of an engine via a pin, and a hole into which the pivot is inserted. A shaft defining a position of the pin as a moving center. A stopper attached to the pivot and the shaft for urging the pivot inward of the hole; and a guide surface protruding from the stopper toward the side of the pivot. The guide surface has a retaining surface facing the end of the pin.
Note that the shaft has only to have at least a hole into which the pivot is inserted, and is not limited to a shaft. Therefore, the shaft can be read as a "pivot locking member" or a "pivot position defining member".

Further, it is preferable that a pair of the retaining surfaces is provided, and both the one end and the other end of the pin are opposed to each other.
( 2 ) It is preferable that the retaining surface has a predetermined gap with respect to an end of the pin. That is, it is preferable that the retaining surface and the pin do not always come into contact with each other.

( 3 ) It is preferable that the retaining surface is formed in a vertically long shape along the axial direction of the pivot.
( 4 ) It is preferable that the guide surface has a tip shape that warps in a direction away from the pivot.
( 5 ) Preferably, the stopper has a bent shape that sandwiches the pivot and the shaft inside.

( 7 ) Preferably, the stopper has a locking portion locked to the shaft, and a spring portion for applying an elastic force for urging the pivot in the direction of the locking portion.
( 8 ) Preferably, the hole extends in a direction orthogonal to a central axis of the shaft, and the shaft is rotatably provided around the central axis.

  By providing a stopper for urging the pivot in the direction of the inside of the hole of the shaft, the movement and dropping of the pivot can be prevented, and the workability of assembling the valve train can be improved. In addition, since the guide surface protrudes from the stopper, the stopper can be easily mounted at a correct position, so that the workability of assembling the stopper can be improved.

1 is a cross-sectional view of an engine to which a valve train according to an embodiment is applied. FIG. 3 is an exploded perspective view of a valve operating mechanism. It is a perspective view of a stopper. FIG. 4 is a side sectional view of the valve operating mechanism showing the stopper in an enlarged manner. FIG. 5 is a cross-sectional view of the stopper and the pin (a cross-sectional view along the line AA in FIG. 4).

  A valve train as an embodiment will be described with reference to the drawings. The embodiment described below is merely an example, and there is no intention to exclude various modifications and application of technology not explicitly described in the following embodiment. Each configuration of the present embodiment can be variously modified and implemented without departing from the spirit thereof. Further, they can be selected as needed, or can be appropriately combined.

[1. Device configuration]
The valve train 10 of the present embodiment is applied to a reciprocating engine 50 shown in FIG. The engine 50 is equipped with a continuously variable valve lift mechanism of the SOHC type, and the valve lift of each of the intake valve 51 and the exhaust valve 52 can be freely changed. As shown in FIG. 1, the upper end of the intake valve 51 is supported by the intake rocker arm 41 so as to be able to reciprocate up and down. Similarly, the upper end of the exhaust valve 52 is supported by an exhaust rocker arm (not shown) so as to be able to reciprocate up and down. The intake valve 51 and the exhaust valve 52 are constantly urged upward by a valve spring, and open their intake ports and exhaust ports by pushing down their upper ends.

  The power transmission members for driving the intake valve 51 are the intake cam 12, the intake center rocker arm 21 (rocker arm), the intake swing cam 31, and the intake rocker arm 41 in the order in which the power is transmitted. 1, power transmission members for driving the exhaust valve 52 are an exhaust cam 13, an exhaust center rocker arm, an exhaust swing cam, and an exhaust rocker arm. The valve lift amounts of the intake valve 51 and the exhaust valve 52 can be changed by changing the swing amounts of the intake rocker arm 41 and the exhaust rocker arm, and these swing amounts change the positional relationship and contact position between the power transmission members. It can be changed by changing it continuously.

  The intake cam 12 and the exhaust cam 13 are cam members having an oval cross section fixed to the camshaft 11. The camshaft 11 is a shaft member that rotates at a predetermined rotation speed ratio in conjunction with a crankshaft of the engine 50, and is pivotally supported by a cylinder head. The intake cam 12 is arranged so as to contact the center roller 23 of the intake center rocker arm 21 and presses the intake center rocker arm 21 with an amplitude corresponding to the cam profile. Similarly, the exhaust cam 13 swings and drives the exhaust center rocker arm.

  These cams 12 and 13 are attached to the camshaft 11 such that the radially projecting portion of the intake cam 12 and the radially projecting portion of the exhaust cam 13 have different phases. As a result, a phase difference occurs between the swing of the intake rocker arm 41 and the swing of the exhaust rocker arm, and the opening timing (valve timing) of the intake valve 51 and the exhaust valve 52 is determined accordingly. Hereinafter, the intake center rocker arm 21, the intake swing cam 31, and the intake rocker arm 41, which are power transmission members for driving the intake rocker arm 41, will be described in detail.

  As shown in FIG. 1, the intake center rocker arm 21 is a member that is locked to the intake rocker shaft 1 in a posture sandwiched between the intake cam 12 and the intake swing cam 31. The intake center rocker arm 21 is provided with a main body 22, a center roller 23, a center pressing portion 24, a pivot 25, and a pin 27, as shown in FIG. The main body portion 22 is a member having a shape in which boomerang-shaped side plates are arranged and connected in the extending direction of the camshaft 11. The center roller 23 is a portion that receives a pressing force from the intake cam 12, and is rotatably supported between a pair of side plates forming the main body 22. Further, a center pressing portion 24 for transmitting the swing of the main body 22 to the intake swing cam 31 is formed in a flat (or curved) shape at a portion connecting the pair of side plates. On the other hand, a shaft-shaped pivot 25 rotatably connected via a pin 27 is provided on the opposite side of the center pressing portion 24 with respect to the center of rotation of the center roller 23.

  The pivot 25 is a shaft-like member that is inserted and locked into a pivot hole 2 formed in the intake rocker shaft 1 described later, and has a function of defining a position of a pin 27 serving as a swing center of the intake center rocker arm 21. have. The upper end side of the pivot 25 is formed in a cylindrical shape having a diameter corresponding to the size of the pivot hole 2, and the lower end side is formed in a slightly enlarged cylindrical shape or spherical shape. On the other end side, a hollow cylindrical pin hole 26 formed in a direction perpendicular to the axial direction of the pivot 25 is provided.

  The pin 27 is a shaft-like member that is loosely inserted into the pin hole 26 and fitted into a pin hole 28 that is bored at one end of the intake center rocker arm 21. A predetermined gap is provided between the pin 27 and the pin hole 26 so that the pivot 25 can take an arbitrary angle with respect to the intake center rocker arm 21. On the other hand, the pin 27 is inserted into the pin hole 28 without any gap so that the pin 27 does not come off. The pin 27 may be press-fitted into the pin hole 28 or may be fixed by caulking.

  The intake rocker shaft 1 is a shaft member (shaft) on which the intake rocker arm 41 is swingably supported, and is supported so as to be rotatable around the axis with respect to the cylinder head of the engine 50. The intake rocker shaft 1 has a pivot hole 2 into which a pivot 25 is inserted and locked. The lower end side of the inner peripheral surface of the pivot hole 2 into which the pivot 25 is inserted is formed in a smooth cylindrical surface on which the pivot 25 can slide. On the other hand, a screw groove is formed on the inner peripheral surface on the upper end side of the pivot hole 2, and the adjusting screw 3 for defining the position of the pivot 25 is fastened and fixed. Thereby, the position of the pivot 25 is a position where the tip of the pivot 25 is in contact with the lower end surface of the adjusting screw 3. Further, by pivoting the intake rocker shaft 1 around the axis, the pivot 25 inserted into the intake rocker shaft 1 rotates around the axis of the intake rocker shaft 1 together with the pin 27, so that the swing of the intake center rocker arm 21 is caused. The center also moves around the axis of the intake rocker shaft 1.

  The intake swing cam 31 is a power transmission member for transmitting the swing of the intake center rocker arm 21 to the intake rocker arm 41. The intake swing cam 31 is provided with a main body part 32, a cam roller 33, and an arm pressing part 34. The main body portion 32 is a portion that is swingably attached to the swing camshaft 35, and is mounted around the outer peripheral surface of the swing camshaft 35 in a state where the main body portion 32 is biased in the clockwise direction in FIG. The swing cam shaft 35 is a shaft member (shaft) on which the intake swing cam 31 is swingably supported, and is supported or fixed to a cylinder head of the engine 50. If the entire shape of the main body 32 is conformed to the shape of boots, the upper end of the boots is supported by the swing cam shaft 35. The cam roller 33 is attached to the heel portion of the boot, and the arm pressing portion 34 is a portion corresponding to the shoe sole.

  The cam roller 33 is a portion that is pressed by contacting the center pressing portion 24 of the intake center rocker arm 21, and is rotatably supported by the main body 32. The arm pressing part 34 is a part that transmits the swing of the main body 32 to the intake rocker arm 41. The surface shape of the arm pressing portion 34 is a complicated curved surface shape in which a plurality of curved surfaces having different curvatures are connected. Thus, the swing amount transmitted to the intake rocker arm 41 changes according to the contact position of the intake rocker arm 41 with the arm pressing portion 34.

  The intake rocker arm 41 is a power transmission member for transmitting the swing transmitted from the intake swing cam 31 to the intake valve 51. The intake rocker arm 41 is provided with a main body 42, an arm roller 43, and a valve pressing portion 44. The main body 42 is a part that is swingably attached to the intake rocker shaft 1, and is installed around the outer peripheral surface of the intake rocker shaft 1. The main body portion 42 of the present embodiment is formed in a shape such that triangular side plates are arranged and connected in the extending direction of the intake rocker shaft 1, and the intake rocker shaft 1, the arm roller 43, and the valve are provided at the top of the triangle. Each of the pressing parts 44 is arranged. The pivot hole 2 of the intake rocker arm 41 is formed at a position between the pair of side plates.

  The arm roller 43 is a portion that receives a pressing force from the arm pressing portion 34 and is rotatably supported between a pair of side plates forming the main body 42. The valve pressing portion 44 is a portion that presses the upper end of the intake valve 51, and is provided one for each of the pair of side plates. As described above, the intake rocker arm 41 of the present embodiment is provided with the two valve pressing portions 44 in order to correspond to the engine 50 in which one intake valve 51 is provided in one cylinder.

  A stopper 4 is attached between the intake rocker shaft 1 and the pivot 25 to fix them while sandwiching them. The stopper 4 is a member that is attached to the intake rocker shaft 1 and the pivot 25 and has both a function of urging the pivot 25 inward of the pivot hole 2 and a function of preventing the pin 27 from dropping or moving. The overall shape of the stopper 4 is shown in FIG. 3, and its cross-sectional shape is shown in FIGS.

  As shown in FIG. 3, the stopper 4 is provided with a locking portion 5, a spring portion 6, a guide surface 7, and a retaining surface 8. The locking part 5 is a part on one end side locked to the intake rocker shaft 1, and the spring part 6 is a part on the other end side. The locking portion 5 and the spring portion 6 are formed, for example, by bending a vertically long steel plate into a C-shape to sandwich the pivot 25 and the intake rocker shaft 1 inside thereof. Thereby, the spring portion 6 is a portion that applies an elastic force to bias the pivot 25 in the direction of the locking portion 5.

  The locking portion 5 is formed in a planar shape so as to be in surface contact with the seat surface of the adjusting screw 3 attached to the intake rocker shaft 1, and has a shape cut out in an arc shape so as not to interfere with the adjusting screw 3. Have. In the vicinity of the tip of the locking portion 5, a wall contact portion 46 and a projection 48 are provided. The wall contact portion 46 is a portion that comes into surface contact with the wall 45 of the intake rocker shaft 1 erected from the seating surface of the adjusting screw 3. The protrusion 48 is a portion that fits into a recess 47 formed in the axial direction of the intake rocker shaft 1 on a surface facing the wall surface 45 with which the wall contact portion 46 makes surface contact. Thus, the position where the stopper 4 is disposed with respect to the intake rocker shaft 1 is uniquely specified, and good positioning accuracy is obtained.

  The spring portion 6 is formed in a concave shape corresponding to the shape of the lower end side of the pivot 25. The dimension in the width direction of the spring portion 6 (the dimension in the axial direction of the pin 27) is set so that the spring portion 6 contacts only the pivot 25 and does not contact the main body portion 22 of the intake center rocker arm 21. , The pivot 25 is formed narrower than the width dimension. As a result, the swingability of the intake center rocker arm 21 is ensured, and the occurrence of operation failure due to the contact between the stopper 4 and the intake center rocker arm 21 is prevented.

  A pair of guide surfaces 7 projecting in the form of arms toward the side surface of the pivot 25 is provided slightly above the spring portion 6. As shown in FIG. 3, each guide surface 7 is formed in a crank shape avoiding contact with the intake rocker shaft 1 and the intake center rocker arm 21. At the tip of the guide surface 7, a tip 9 having a shape that is warped in a direction away from the pivot 25 is provided. As shown in FIG. 5, the interval between the left and right tip portions 9 is formed to be larger than the thickness dimension of the portion where the pin hole 28 is formed at least in the main body 22 of the intake center rocker arm 21. This prevents interference with the intake center rocker arm 21 when the stopper 4 is assembled.

  The guide surface 7 is provided with retaining surfaces 8 facing both ends of the pins 27. As shown in FIG. 4, the retaining surface 8 is disposed at a position overlapping the pin 27 when viewed from the extending direction of the pin 27. As described above, the center position of the pin 27 with respect to the intake rocker shaft 1 can be changed by adjusting the adjusting screw 3. In order to cope with such a position change, the retaining surface 8 is formed in a vertically long shape along the axial direction of the pivot 25, as shown in FIG. Thereby, even if the position of the pivot 25 changes in the axial direction, both ends of the pin 27 are always covered by the retaining surface 8 (facing the front). In addition, a predetermined gap is formed between the retaining surface 8 and both ends of the pin 27. Thereby, the swingability of the intake center rocker arm 21 is ensured.

[2. Action, effect]
(1) In the valve train 10 described above, the pivot 25 is rotatably connected to the intake center rocker arm 21 via the pin 27. Further, a pivot hole 2 for inserting the pivot 25 is formed in the intake rocker shaft 1, and the pivot 25 is locked to the intake rocker shaft 1. In such a structure, by providing the stopper 4 for urging the pivot 25 toward the inside of the pivot hole 2, the movement and dropping of the pivot 25 can be prevented, and the assembling workability of the valve train 10 is improved. be able to. In addition, since the guide surface 7 protrudes from the stopper 4, the stopper 4 can be easily attached to a correct position.

  (2) The guide surface 7 is provided with a retaining surface 8 facing the end of the pin 27. Thus, a function of preventing the pin 27 from coming off can be added to the guide surface 7, and the occurrence of abnormal noise and rattling due to the loosening of the pin 27 can be prevented. Further, the press-fitting work and the caulking work of the pin 27 can be omitted, or the press-fitting torque and the strength of the caulking can be reduced, so that the work load can be reduced. Furthermore, by assembling the stopper 4, the pins 27 do not drop out in the assembling process, so that the assembling workability can be further improved.

  (3) As shown in FIG. 5, since the retaining surface 8 has a predetermined gap with respect to the end of the pin 27, generation of abnormal noise and rattling due to contact between the pin 27 and the retaining surface 8 is generated. Can be prevented. In addition, if the retaining surface 8 is in contact with the end of the pin 27 in the assembling step, it can be seen that some assembling error has occurred, so that the assembling quality can be improved.

  (4) As shown in FIG. 4, the retaining surface 8 is formed in a vertically long shape along the axial direction of the pivot 25. Thereby, even if the position of the pivot 25 changes in the axial direction, it is possible to always cover both ends of the pin 27 so as to face the front surface of the retaining surface 8. Therefore, the function of retaining the pin 27 can be further enhanced.

  (5) As shown in FIG. 3, the distal end 9 of the guide surface 7 is formed in a shape warped in a direction away from the pivot 25. Thereby, interference with the intake center rocker arm 21 when the stopper 4 is assembled can be prevented. In addition, since the intake center rocker arm 21 is a member disposed inside the main body 42 of the intake rocker arm 41, it is difficult to visually confirm the stopper, and the stopper 4 is provided so as not to interfere with the intake center rocker arm 21. Installation work is complicated. However, since the distal end portion 9 of the guide surface 7 has a shape that is widened so as to receive the intake center rocker arm 21 inside, the interference with the intake center rocker arm 21 can be more reliably prevented, and the assembling can be performed. Workability can be further improved.

  (6) As shown in FIG. 3, the overall shape of the stopper 4 is a bent shape that sandwiches the pivot 25 and the intake rocker shaft 1 inside. As a result, since the mounting work of the stopper 4 is completed only by sandwiching the pivot 25 and the intake center rocker arm 21 inside the stopper 4, a mounting error hardly occurs, and the assembling quality and the assembling workability are improved. be able to.

  (7) The stopper 4 is provided at one end thereof with a locking portion 5 which is locked to the intake rocker shaft 1, and at the other end thereof has an elastic force for urging the pivot 25 in the direction of the locking portion 5. A spring portion 6 to be provided is provided. As described above, by structurally separating the locking portion 5 and the spring portion 6, the pivot 25 can be stably fixed to the intake rocker shaft 1 regardless of the magnitude of the insertion amount of the pivot 25. The workability of assembling the stopper 4 can be improved. In addition, since the spring portion 6 is provided at the end opposite to the locking portion 5, elastic deformation can be dispersed over substantially the entire stopper 4, and a stable elastic force can be applied to the pivot 25. You can continue to give.

  (8) The above-described valve train 10 employs a continuously variable valve lift valve train. That is, the intake rocker shaft 1 to which the stopper 4 is attached changes its valve lift amount by rotating around the axis according to the operating state of the engine 50. On the other hand, the stopper 4 can continue to support the pivot 25 even if the valve lift is changed, and can prevent the pin 27 from falling off or moving. In this manner, the workability of assembling the valve train 10 can be improved without affecting the existing continuously variable valve lift valve train.

[3. Modification]
In the above-described embodiment, the structure in which the stopper 4 is applied to the power transmission member for driving the intake valve 51 is illustrated. However, the same stopper 4 is applied to the power transmission member for driving the exhaust valve 52. Is also possible. For example, a pivot connected to the exhaust center rocker arm via a pin and an exhaust rocker shaft into which the pivot is inserted may be sandwiched by the stopper 4. Thereby, the same effects as those of the above-described embodiment can be obtained.

  In the above-described embodiment, the stopper 4 sandwiches the pivot 25 of the intake center rocker arm 21 and the intake rocker shaft 1, but the object sandwiched by the stopper 4 is not limited to these. At least in a valve train provided with a rocker arm (swing member) in a power transmission path for driving a valve element of the engine 50, a pivot (shaft member) is connected to one end of the rocker arm via a pin. As long as the pivot is inserted into the hole and locked, the same stopper 4 as in the above embodiment can be applied, and the same effect as in the above embodiment can be obtained.

  In the above-described embodiment, as shown in FIG. 3, the stopper 4 having the crank-shaped guide surface 7 is shown, but the specific shape of the stopper 4 is not limited to this. It is preferable that the shape of the guide surface 7 does not cause interference with the intake rocker shaft 1 and the intake center rocker arm 21, but some interference is allowed unless the interference state is maintained for a long time. You. The same applies to the gap between the retaining surface 8 and the pin 27. It is not necessary to provide an excessively large clearance, and a structure in which the retaining surface 8 and the pin 27 are in contact for a short time may be employed.

1 Intake rocker shaft (shaft)
2 Pivot hole 3 Adjusting screw 4 Stopper 5 Locking part 6 Spring part 7 Guide surface 8 Retaining surface 9 Tip 10 Valve train 11 Camshaft 12 Intake cam 13 Exhaust cam 21 Intake center rocker arm (rocker arm)
22 Body part 23 Center roller 24 Center pressing part 25 Pivot 26 Pin hole 27 Pin 28 Pin hole 31 Intake swing cam 32 Body part 33 Cam roller 34 Arm pressing part 35 Swing cam shaft 41 Intake rocker arm 42 Body part 43 Arm roller 44 Valve Pressing portion 45 Wall surface 46 Wall contact portion 47 Depression 48 Projection 50 Engine 51 Intake valve 52 Exhaust valve

Claims (7)

An axial pivot pivotally connected to the rocker arm of the engine via a pin,
A shaft having a hole into which the pivot is inserted and defining a position of the pin serving as a rocking center of the rocker arm;
A stopper attached to the pivot and the shaft, for urging the pivot inward of the hole;
A guide surface protruding from the stopper toward the side of the pivot ,
The valve gear, wherein the guide surface has a retaining surface facing an end of the pin . The stop surface omission, and having a predetermined clearance relative to the end of the pin, the valve operating apparatus according to claim 1. The stop surface omission, characterized in that it is formed in a vertically long shape along the axial direction of the pivot, the valve operating system according to claim 1 or 2, wherein. The valve train according to any one of claims 1 to 3 , wherein the guide surface has a tip shape warped in a direction away from the pivot. The valve gear according to any one of claims 1 to 4 , wherein the stopper has a bent shape that sandwiches the pivot and the shaft inside. It said stopper, and having a securing portion secured to said shaft, and a spring portion that applies an elastic force for biasing the pivot direction of the locking portion, claim 1-5 The valve train according to any one of the above items. The hole extends in a direction orthogonal to a central axis of the shaft,
The valve gear according to any one of claims 1 to 6 , wherein the shaft is rotatably provided around the central axis.

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