JP5272653B2 - Variable valve gear for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device surely preventing interference of an intake valve and a piston even if an incorrect instruction is output causing valve timing which is not used in control. <P>SOLUTION: This variable valve device includes a lift-operation angle variable mechanism 1 and a phase variable mechanism 21. A first stopper 36A and a second stopper 39 are provided integrally with the phase variable mechanism 21 and the lift-operation angle variable mechanism 1 respectively. The first stopper 36A moves closer to the second stopper 39 as the phase of a lift center angle advances, and the second stopper 39 moves closer to the first stopper 36A as a lift-operation angle gets larger. In any combination of the phase of the lift center angle and lift-operation angle, positions and shapes of the two stoppers 36A, 39 are set to make the two stoppers 36A, 39 abut on each other before at least one of an intake and an exhaust valve interferes with a piston. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an improvement of a variable valve operating apparatus for an engine (internal combustion engine).

As a variable valve system for the engine, the lift / working angle variable mechanism that can simultaneously and continuously expand and reduce the lift / working angle of the intake valve, and the phase of the lift center angle of the intake valve, including the camshaft, are advanced and retarded. Some have a phase variable mechanism (see Patent Document 1). According to this configuration, the combination of the lift / operation angle of the intake valve and the phase of the lift center angle can be arbitrarily set within a range not interfering with the piston.
JP 2002-256905 A

  By the way, in the technique of the above-mentioned patent document 1, the actuator for lift / operating angle control and the actuator for phase control are constituted by, for example, a motor, and a control signal is given to this motor from the engine control unit, so that it corresponds to the operating conditions. The optimum lift / operating angle of the intake valve and the phase of the lift center angle of the intake valve according to the operating conditions are obtained.

  In this case, the valve timing at which the lift / operating angle of the intake valve is large and the phase of the lift central angle is greatly advanced is not controlled. This is to avoid this because the intake and exhaust valves overlap at this time, and the amount of residual gas in the combustion chamber increases and a misfire may occur.

  However, since the lift / operating angle of the intake valve and the phase of the lift central angle of the intake valve are controlled by separate actuators, each actuator has a large lift / operating angle of the intake valve, the lift of the intake valve Since the state in which the phase of the central angle is greatly advanced can be reproduced, the valve timing of a large lift / operation angle and a large advance angle can be realized as hardware. In other words, even when the valve timing is not used for control, a situation where the intake valve approaches the piston and interferes with the piston due to a valve timing different from the valve timing actually used for control due to control error, harness disconnection, etc. Can be considered.

  In order to prepare for such a situation, it is necessary to make the valve recess provided on the piston crown surface deeper in preparation for the intake valve descending into the combustion chamber.

  However, when the valve recess is deepened, the surface area is increased due to an increase in the unevenness of the shape of the combustion chamber, heat loss is increased, and fuel consumption is deteriorated.

  In view of this, the present invention provides an intake valve and a piston, even if an erroneous instruction is output to the lift / operating angle control actuator or the phase control actuator so that the valve timing is not used for control. It is an object of the present invention to provide an apparatus that can reliably prevent interference.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

The present invention includes a lift / working angle variable mechanism (1) capable of simultaneously and continuously expanding and reducing at least one lift / working angle of an intake / exhaust valve, a side gear (87), a pinion mate (83, 84), A differential gear device (82) including a carrier (85) and a ring gear (90), and an actuator (91) including a cam shaft and capable of moving the phase of the lift center angle of at least one of the intake and exhaust valves. the a phase variable mechanism which Susumuoso the phase of the lift center angle (81), said side gears (87), by fixing the one of the ring gear (90), power from the crankshaft of the engine Is transmitted to the camshaft via the differential gear device (82), and the rotational speed of the camshaft is converted to the rotational speed of the crankshaft by using the deceleration by the differential gear device (82). Provided with halving of the phase variable mechanism (81) and the first stopper integrally (94 A), the lift operating angle varying mechanism (1) and the second stopper integrally with (95A), respectively, said first stopper (94 a) approaches said second stopper enough to phase advance of the lift center angle (95A), said second stopper (95A) is the higher the lift operating angle is increased In any combination of the phase of the lift center angle and the lift / operating angle, the two stoppers ( 94A ) approach the at least one of the intake / exhaust valves and the piston before they interfere with each other. stoppers (94 a, 95A) with each other to set the position and shape of the two stoppers so as to abut (94 a, 95A).

According to the present invention, a differential gear comprising a lift / working angle variable mechanism capable of simultaneously and continuously expanding and reducing the lift / working angle of at least one of the intake and exhaust valves, and a side gear, a pinion mate, a carrier, and a ring gear. And a phase variable mechanism that includes a cam shaft and includes an actuator capable of advancing and retarding the phase of the lift center angle of at least one of the intake and exhaust valves . By fixing any one of the ring gears, power from the crankshaft of the engine is transmitted to the camshaft via the differential gear unit, and the cam is used by using the reduction by the differential gear unit. with the rotational speed of the shaft to half of the rotational speed of the crankshaft, the first stopper in the phase variable mechanism integral with the lift operating angle variable mechanism integral A second stopper is provided, and the first stopper approaches the second stopper as the phase of the lift center angle advances, and the second stopper increases as the lift / operation angle increases. The two stoppers come into contact with each other before at least one of the intake and exhaust valves interferes with the piston in any combination of the phase of the lift center angle and the lift / operating angle. Since the position and shape of the two stoppers are set in the valve timing, even if a control error such as a valve timing of a large lift / operating angle and a large advance angle occurs in the valve timing control or the harness is disconnected, Before the valve and the piston interfere with each other, the two stoppers are in mechanical contact with each other. No further advance, and the lift / operating angle of at least one of the intake / exhaust valves does not increase any more, so there is no need to deepen the valve recess drilled in the piston crown (can be shallow) It is possible to improve fuel efficiency.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view showing the configuration of an intake valve side variable valve operating device of an engine. The variable valve operating device is a lift / operating angle variable mechanism 1 that changes the lift / operating angle of an intake valve, and the lift A phase variable mechanism 21 for advancing or retarding the phase of the central angle (phase with respect to a crankshaft (not shown)) is combined.

  First, the lift / operating angle variable mechanism 1 will be described with reference to FIG. In FIG. 2, the left side shows the state of the swing cam when the intake valve lift / operating angle is minimum, and the right side of FIG. 2 shows the swing when the intake valve lift / operating angle is minimum. The state at the time of the maximum swing of the moving cam is shown. The lift / operating angle variable mechanism 1 has been previously proposed by the applicant of the present application. However, since it has been publicly known, for example, in Japanese Patent Application Laid-Open No. 11-107725, only the outline thereof will be described.

  The variable lift / operating angle mechanism 1 includes an intake valve 11 slidably provided on a cylinder head (not shown) and a drive shaft 2 rotatably supported by a cam bracket (not shown) on the cylinder head. And an eccentric cam 3 fixed to the drive shaft 2 by press-fitting or the like, and a control shaft 12 that is rotatably supported by the same cam bracket at a position above the drive shaft 2 and arranged in parallel with the drive shaft 2. And a rocker arm 6 that is swingably supported by an eccentric cam portion 18 (center is P1) of the control shaft 12 (center is P2), and a rocker that is in contact with a tappet 10 disposed at the upper end of each intake valve 11. And a moving cam 9. The eccentric cam 3 and the rocker arm 6 are linked by a link arm 4, and the rocker arm 6 and the swing cam 9 are linked by a link member 8.

  As will be described later, the drive shaft 2 is driven by a crankshaft of an engine via a timing chain or a timing belt, and functions as a camshaft.

  The eccentric cam 3 has a circular outer peripheral surface, and the center of the outer peripheral surface is offset from the shaft center of the drive shaft 2 by a predetermined amount, and the annular portion of the link arm 4 is rotatable on the outer peripheral surface. It is mated.

  The rocker arm 6 has a substantially central portion supported by the eccentric cam portion 18 so as to be swingable, and an arm portion of the link arm 4 is linked to one end portion thereof via a connecting pin 5. The upper end portion of the link member 8 is linked to the end portion via the connecting pin 7. The eccentric cam portion 18 is eccentric from the axis of the control shaft 12, and accordingly, the rocking center of the rocker arm 6 changes according to the angular position of the control shaft 12.

  The rocking cam 9 is fitted to the outer periphery of the drive shaft 2 and is rotatably supported, and the lower end portion of the link member 8 is linked to the end portion extending sideways via a connecting pin 17. ing. On the lower surface of the swing cam 9, a base circle surface concentric with the drive shaft 2 and a cam surface extending in a predetermined curve from the base circle surface are continuously formed. These base circle surface and cam surface are in contact with the upper surface of the tappet 10 according to the swing position of the swing cam 9.

  That is, the base circle surface is a section where the lift amount becomes zero as the base circle section, and when the swing cam 9 swings and the cam surface contacts the tappet 10, the lift is gradually lifted. A slight ramp section is provided between the base circle section and the lift section.

  As shown in FIG. 1, the control shaft 12 is configured to rotate within a predetermined angle range by a lift / operation angle control actuator 13 provided at one end. The lift / operating angle control actuator 13 includes, for example, a servo motor that drives the control shaft 12 via the worm gear 15, and is controlled by a control signal from the engine control unit 19. The rotation angle of the control shaft 12 is detected by the control shaft sensor 14.

  The operation of the lift / operating angle variable mechanism 1 will be described. When the drive shaft 2 rotates, the link arm 4 moves up and down by the cam action of the eccentric cam 3, and the rocker arm 6 swings accordingly. The swing of the rocker arm 6 is transmitted to the swing cam 9 via the link member 8, and the swing cam 9 swings. The tappet 10 is pressed by the cam action of the swing cam 9, and the intake valve 11 is lifted.

  Here, when the angle of the control shaft 12 changes via the lift / operation angle control actuator 13, the initial position of the rocker arm 6 changes, and consequently, the initial swing position of the swing cam 9 changes.

  For example, if the eccentric cam portion 18 is positioned upward in FIG. 1, the rocker arm 6 is positioned upward as a whole, and the end of the swing cam 9 on the side of the connecting pin 17 is relatively lifted upward. It becomes. That is, the initial position of the swing cam 9 is inclined in a direction in which the cam surface is separated from the tappet 10. Therefore, when the swing cam 9 swings as the drive shaft 2 rotates, the base circle surface is kept in contact with the tappet 10 for a long time, and the period during which the cam surface is in contact with the tappet 10 is short. Therefore, the lift amount is reduced as a whole, and the angle range from the opening timing to the closing timing, that is, the operating angle is also reduced (see FIG. 2).

  On the contrary, if the eccentric cam portion 18 is positioned downward in FIG. 1, the rocker arm 6 is positioned downward as a whole, and the end portion of the swing cam 9 on the side of the connecting pin 17 is pushed downward relatively. It becomes the state. That is, the initial position of the swing cam 9 is inclined in a direction in which the cam surface approaches the tappet 10. Therefore, when the swing cam 9 swings as the drive shaft 2 rotates, the portion that contacts the tappet 10 immediately shifts from the base circle surface to the cam surface. Therefore, the lift amount is increased as a whole, and the operating angle is increased.

  Since the initial position of the eccentric cam portion 18 can be continuously changed, the valve lift characteristic is continuously changed accordingly. That is, the lift and the operating angle can be continuously expanded and contracted simultaneously. Depending on the layout of each part, for example, the opening timing and closing timing of the intake valve 11 change substantially symmetrically as the lift and operating angle change.

  Next, in the conventional device (Japanese Patent Laid-Open No. 2002-256905), the phase variable mechanism 21 has a sprocket provided at the front end of the drive shaft 2, and the sprocket and the drive shaft 2 within a predetermined angular range. And a phase control actuator that relatively rotates inside. The sprocket is linked to the crankshaft via a timing chain or timing belt (not shown). The phase control actuator is composed of, for example, a hydraulic or electromagnetic rotary actuator, and is controlled by a control signal from the engine control unit 19. Due to the action of the phase control actuator, the sprocket and the drive shaft 2 are relatively rotated, and the lift center angle in the valve lift is retarded. In other words, the lift characteristic curve itself does not change, and the whole advances or retards.

  Now, it is not controlled to set the valve timing at which the lift / operating angle of the intake valve 11 is large and the phase of the lift central angle is greatly advanced. This is to avoid this because the intake and exhaust valves overlap at this time, and the amount of residual gas in the combustion chamber increases and a misfire may occur.

  However, the lift / operating angle of the intake valve 11 is controlled by the lift / operating angle control actuator 13, and the phase of the lift center angle of the intake valve 11 is controlled by the phase control actuator. Since it is possible to reproduce the state where the lift / working angle is large and the phase of the lift center angle of the intake valve 11 is greatly advanced, it is possible to make the valve timing of large lift / working angle and large advancement as hardware. . That is, even if the valve timing is not used for control, the intake valve 11 approaches the piston because the valve timing is different from the valve timing actually used for control due to a control error in the engine control unit 19, harness disconnection, or the like. The situation where the piston and the piston interfere.

  To prepare for such a situation, the valve recess (dimple) provided on the piston crown surface should be made deeper in preparation for the intake valve descending into the combustion chamber, but if the valve recess is deepened, the shape of the combustion chamber Increased surface roughness increases the surface area, increases heat loss, and deteriorates fuel consumption.

  Therefore, in the present invention, a mechanical stopper including a first stopper and a second stopper is newly provided so that the large lift / operation angle and the large advance angle do not coexist. In other words, the first stopper is provided integrally with the phase variable mechanism 21 and the second stopper is provided integrally with the variable lift / operating angle mechanism 1, and the first stopper has an advance angle of the lift center angle of the intake valve 11. The closer the second stopper is to the second stopper, the closer the second stopper is to the first stopper as the lift / operating angle of the intake valve 11 increases, and the lift center angle of the intake valve 11 and the lift / In any combination with the operating angle, the positions and shapes of the two stoppers are set so that the two stoppers come into contact with each other before the intake valve 11 and the piston interfere with each other.

Specifically, the phase variable mechanism 21 is different from the conventional device (Japanese Patent Laid-Open No. 2002-256905). Here, a reference example for the present invention will be described first, and then an embodiment of the present invention will be referred to. That is, in the first reference example, the phase variable mechanism 21 includes a planetary gear mechanism including a sun gear, a planet pinion, a planet carrier, and a ring gear, and an actuator that can advance and retard the phase of the lift center angle of the intake valve 11. By fixing the carrier, power from the crankshaft of the engine is transmitted to the drive shaft 2 (camshaft) via this planetary gear mechanism, and the rotational speed of the camshaft is reduced using the deceleration by this planetary gear mechanism. Reduce the rotation speed of the crankshaft to half. Then, the planet carrier is provided with the first stopper, the lift / operating angle variable mechanism 1 is provided with the second stopper on the control shaft 12, and the two stoppers are brought into contact with each other before the intake valve 11 and the piston interfere with each other. In the abutted state, the phase of the lift central angle of the intake valve 11 is not advanced any further, and the lift / operation angle of the intake valve 11 is not further increased. As a result, no matter what control error occurs in the valve timing control, the two stoppers come into contact with each other before the intake valve 11 and the piston interfere with each other. Shallowness can be achieved, and fuel consumption can be improved.

  It is known in US Pat. No. 2,984,745 and US Pat. No. 4,747,375 that the phase variable mechanism is composed of a planetary gear mechanism and an actuator capable of advancing and retarding the phase of the lift center angle of the intake valve. However, these known techniques cannot solve the problem of the present invention that the intake valve and the piston may interfere with each other due to a valve timing that is not used for control depending on a control error.

Next, the phase variable mechanism 21 of the first reference example will be described with reference to FIGS. In FIG. 1, the phase variable mechanism 21 is shown as a block for the sake of convenience. Actually, in FIG. 1, the rear end portion (the left end portion in FIG. 1) of the drive shaft 2 and the control shaft 12 and the sensors 14 and 16. It is provided between.

FIG. 3 is a schematic cross-sectional view of the phase variable mechanism 21 of the first reference example , and FIG. 4 is an arrow view taken along line AA of FIG. The left side of FIG. 4 shows the behavior at a large lift / operating angle, and the right side of FIG. 4 shows the behavior at a small lift / operating angle.

  The phase variable mechanism 21 includes a planetary gear mechanism 22 including a sun gear 23, a ring gear 24, a planet pinion 25 and a planet carrier 26, and a phase control actuator that relatively rotates the planet carrier 26 within a predetermined angle range. 41.

  First, in the planetary gear mechanism 22, as shown in FIG. 3, the ring gear 24 is fixed to the rear end (left end) of the drive shaft 2 by a bolt 27, and the sun gear 23 is rotatably provided to the ring gear 24. It has been. A sprocket 31 is integrally provided at the left end of the sun gear 23 through an extending portion extending to the rear portion of the planet carrier 26, and a chain 32 is hung around the sprocket 31 and a crank sprocket (not shown) to thereby sprocket 31. That is, the sun gear 23 is driven to rotate by the crankshaft. Oil holes 28 and 29 are provided for lubrication between the ring gear 24 and the sun gear 23.

  The planet carrier 26 is formed in a direction orthogonal to the drive shaft 2 behind the ring gear 24 and substantially in a ring shape as shown in FIG. 4, and the center of the ring shape coincides with the axis of the drive shaft 2. . A phase control actuator 41 including a worm gear 42 and a motor 43 that drives the worm gear 42 is provided on the outer periphery of the planet carrier 26. That is, teeth that mesh with the worm gear 42 are formed on the outer periphery of the planet carrier 26.

  When the motor 43 is not energized, the planet carrier 26 is fixed. At this time, the phase of the drive shaft 2 (cam shaft) with respect to the crankshaft is determined. The rotational force from the crankshaft is transmitted in the order of the sun gear 23, the planet pinion 25, the ring gear 24, and the drive shaft 2. Therefore, by adjusting the number of teeth of the sprocket 31, the sun gear 23, the planet pinion 25, and the ring gear 24, the drive shaft 2 (cam shaft) can be rotated at a rotational speed that is 1/2 that of the crankshaft.

  On the other hand, the phase of the drive shaft 2 with respect to the crankshaft is changed by energizing the motor 43 and rotating the planet carrier 26 within a predetermined angle range. That is, the rotation amount of the planet carrier 26 is controlled by the phase control actuator 41, and the phase control actuator 41 is controlled by a control signal from the engine control unit 19.

  For example, when the planet carrier 26 rotates clockwise in FIG. 4, the crankshaft and the drive shaft 2 rotate relatively, and the lift central angle of the intake valve in the valve lift advances. If the planet carrier 26 is rotated counterclockwise in FIG. 4 in this state, the lift central angle of the intake valve in the valve lift is retarded and returns to the original position. In other words, the entire lift angle is retarded without changing the lift characteristic curve itself of the intake valve. This change can also be obtained continuously. The control state of the phase variable mechanism 21 is detected by the drive shaft sensor 16 that responds to the rotational position of the drive shaft 2.

  The control of the lift / operating angle variable mechanism 1 and the phase variable mechanism 21 is not limited to the closed loop control based on the detection of the sensors 14 and 16, and may be simply open loop controlled according to the operating conditions. .

Next, mechanical stoppers provided in the phase variable mechanism 21 and the lift / operating angle variable mechanism 1 of the first reference example will be described.

  An extension portion 26A extending from the outer periphery of the planet carrier 26 to the front surface of the ring gear 24 (right side in FIG. 3) in the direction of the drive shaft 2 and a flange portion 26B positioned at the tip of the extension portion are provided. A support member 35 and a planet carrier 26 located on the front surface of the ring gear 24 are fixed. The support member 35 is provided in a direction orthogonal to the drive shaft 2 as in the planet carrier 26.

  A ring-shaped member 36 having a predetermined thickness that is smaller than the outer diameter of the planet carrier 26 is further fixed to the front surface of the support member 35, and the center of the ring-shaped member 36 is driven as shown in FIG. The axis is aligned with the axis of the axis 2. Here, C in FIG. 4 is a line passing through the axis of the drive shaft 2. The ring-shaped member 36 is formed with a protrusion 36A (first stopper) having a shape bulging upward in FIG.

  On the other hand, a disk-shaped member 38 is fixed to the rear end portion of the control shaft 12, and a pin 39 (second stopper) protruding rearward (leftward in FIG. 3) from the disk-shaped member 38 is a disk-shaped member 38. It is provided eccentric from the shaft.

  Since the ring-shaped member 36 having the protruding portion 36A moves integrally with the planet carrier 26, the protruding portion 36A is pinned as the planet carrier 26 rotates clockwise in FIG. 4 and the phase of the drive shaft 2 advances with respect to the crankshaft. Approach 39. Further, the pin 39 approaches the protrusion 36A as the control shaft 12 rotates clockwise in FIG. 4 and the lift / operation angle of the intake valve increases. That is, the projection 36A and the pin 39 come into contact with each other at a predetermined advance amount and a predetermined lift / operation angle, and after the projection 36A and the pin 39 are in contact with each other, Further, the planet carrier 26 cannot be rotated (advanced) in the clockwise direction, nor can the control shaft 12 be rotated in the clockwise direction (the lift / operating angle of the intake valve is increased). Therefore, in any combination of lift / operation angle and advance amount (phase), the ring-shaped member 36 is arranged so that the projection 36A and the pin 39 come into contact with each other before the intake valve 11 and the piston interfere with each other. If the position and shape of the protrusion 36A and the position and shape of the pin 39 in the disk-like member 38 are determined in advance, interference between the intake valve and the piston can be prevented.

As described above, the first reference example is provided with the mechanical stopper composed of the protrusion 36A and the pin 39 so that the large lift / operation angle and the large advance angle do not coexist. For this reason, the lift / operating angle control actuator 13 and the motor 43 (for phase control) are controlled from the engine control unit 19 so that a combination of a lift / operating angle and an advance amount that are not used in the control due to a control error and disconnection of the harness. Even if an erroneous control signal is output to the actuator 41), it is possible to increase the lift / operation angle or increase the advance amount only to the position where the protrusion 36A and the pin 39 abut. Since this is not possible, interference between the intake valve 11 and the piston can be reliably prevented.

  More specifically, in the case of a large lift / operating angle, the pin 39 is shifted to the left as shown on the left side of FIG. 4, so that the rotation of the planet carrier 26 in the clockwise direction is greatly restricted. On the other hand, in the case of a small lift / operating angle, the pin 39 is shifted to the right as shown on the left side of FIG. 4, so that the clockwise rotation restriction of the planet carrier 26 is relaxed and the advance amount is increased. Can do. In FIG. 4, the members constituting the lift / operating angle variable mechanism 1 are shown in an overlapping manner so that the positional relationship between the mechanical stoppers (36A, 39) can be clearly understood.

Thus, in the first reference example , as shown in FIG. 5, the lift center angle of the intake valve (simply expressed as “center angle” in the drawing) and the intake valve are provided by the newly provided mechanical stopper (36 </ b> A, 39). It is now possible to mechanically regulate the boundary (indicated by the slanted solid line) in a region where both the lift and the operating angle (simply indicated as “operating angle” in the figure) are large.

  In FIG. 5, the boundary in the region where both the lift center angle and the lift / operation angle are large is indicated by an oblique straight line, but this is not a limitation. That is, by changing the profile of the mechanical stopper (the contour and shape of the protrusion 36A and the pin 39), it is possible to obtain desired characteristics in a region where both the lift center angle and the lift / operation angle are large. For example, when a valve piston interference limit line is entered, this line becomes a downwardly convex curve as shown in FIG. Accordingly, the boundary in the region where both the lift center angle and the lift / operation angle are large may be a curve having a margin for this curve. The curve can be obtained by resetting the profile of the protrusion 36A as shown in FIG. Further, as shown in FIG. 8, the control shaft 12 side can also be obtained by using a disk-shaped member 40 having a protrusion 40 </ b> A instead of the pin 39. That is, instead of the disk-shaped member 38 and the pin 39, a disk-shaped member 40 having a protrusion 40A is fixed to the rear end of the control shaft 12, and the protrusion 40A of the disk-shaped member and the protrusion 36A on the planet carrier 26 side are fixed. In this case, a curve having a margin with respect to the valve piston interference limit line shown in FIG. 6 is obtained.

Here, the effect of the first reference example will be described.

According to the first reference example , the lift / working angle variable mechanism 1 that can simultaneously and continuously expand and reduce the lift / working angle of the intake valve 11 and the phase of the lift center angle of the intake valve 11 including the camshaft. And a phase variable mechanism 21 for advancing / delaying, and a protrusion 36A, which is a first stopper integrated with the phase variable mechanism 21, is a second stopper integrated with the control shaft 12 (lift / operating angle variable mechanism 1). A pin 39 is provided, and the protrusion 36A approaches the pin 39 as the lift central angle of the intake valve 11 advances, and the pin 39 approaches the protrusion 36A as the lift / operation angle of the intake valve 11 increases. In any combination of the phase of the lift center angle of the intake valve 11 and the lift / operation angle of the intake valve 11, the protrusion 36A and the pin 39 are brought into contact with each other before the intake valve 11 and the piston interfere with each other. Protrusion Since the position and shape of 36A and the pin 39 are set, even if a control error such as a valve timing of a large lift / operating angle and a large advance angle occurs in the valve timing control or a harness disconnection occurs, the intake valve Before the 11 and the piston interfere with each other, the protrusion 36A and the pin 39 mechanically contact each other, and in the contact state, the phase of the lift center angle of the intake valve 11 does not advance any further, and the intake valve Since the lift / operating angle of 11 does not increase any more, the valve recess formed in the piston crown surface can be made shallower, and the fuel efficiency can be improved.

Next, FIGS. 9 and 10 are schematic sectional views of the phase variable mechanisms 51 and 61 of the second and third reference examples , which replace FIG. 3 of the first reference example . However, the control shaft 12 and the mechanical stopper are not shown because they may be provided in the same manner as in the first reference example .

First, referring to FIG. 9, in the second reference example , the phase variable mechanism 51 includes a sun gear 23, a ring gear 24, a planetary pinion 25 meshing with the sun gear 23, a planetary gear mechanism 52 including a planet carrier 26, a worm gear 42, and a motor. It is the same as the first reference example in that it comprises a phase control actuator 41, but the positions of the planet carrier 26 and the ring gear 24 are reversed from those of the first reference example, and the planet carrier 26 is fixed to the drive shaft 2. The ring gear 24 is driven by the phase control actuator 41.

  This will be specifically described. The sun gear 23 is provided with shaft portions 23A and 23B at the front end (right end in FIG. 9) and the rear end (left end in FIG. 9), respectively. The sun gear as a whole has the drive shaft 2 at the rear end (left end) of the drive shaft 2. It is provided at a coaxial position. The shaft portion 23B at the rear end of the sun gear 23 is rotatably supported by the cover 53, and the shaft portion 23A at the front end of the sun gear 23 is rotatably supported by the drive shaft 2. An oil hole 54 for supplying oil communicates with the sliding portion between the shaft portion 23A and the drive shaft 2.

  A planet pinion 25 meshes with the sun gear 23, and a planet carrier 26 is provided in front of the ring gear 24 (to the right in FIG. 9) unlike the first embodiment, and is fixed to the drive shaft 2.

  The ring gear 24 is located outside the planet pinion 25, and a phase control actuator 41 including a worm gear 42 and a motor 43 that drives the worm gear 42 is provided on the outer periphery of the ring gear 24. That is, teeth that mesh with the worm gear 42 are formed on the outer periphery of the ring gear 24.

  For this reason, the ring gear 24 is fixed when the motor 43 is not energized. At this time, the phase of the drive shaft 2 (cam shaft) with respect to the crankshaft is determined. On the other hand, the phase of the drive shaft 2 with respect to the crankshaft is changed by energizing the motor 43 and rotating the ring gear 24 within a predetermined angle range. That is, the rotation amount of the ring gear 24 is controlled by the phase control actuator 41, and the phase control actuator 41 is controlled by the control signal from the engine control unit 19.

In the second reference example , the ring-shaped member 36 having the protrusion 36 </ b> A (first stopper) described in the first reference example moves relative to the ring gear 24 so as to move integrally with the ring gear 24. A ring-shaped member 36 having 36A (first stopper) is provided. On the other hand, as described in the first reference example , the disc-shaped member 38 is fixed to the rear end portion of the control shaft 12, and a pin 39 (second stopper) protruding rearward of the disc-shaped member 38 is disc-shaped. It is provided eccentric from the axis of the member 38.

Next, turning to FIG. 10, in the third reference example , the phase variable mechanism 61 includes a first planetary gear mechanism 62 including a sun gear 23, a ring gear 24, a planet pinion 25 meshing with these, and a planet carrier 26, and a phase Although it is the same as the first reference example in that it is composed of a control actuator, a second planetary gear mechanism 63 is used instead of the phase control actuator comprising the worm gear 42 and the motor 43 of the first reference example. The phase control actuator includes a motor 71 that drives the second planetary gear mechanism 63.

  This will be specifically described. The second planetary gear mechanism 63 is also composed of a sun gear (motor shaft 71A), a ring gear (formed on the motor housing 66), a planet pinion 64 and a planet carrier 65 meshing with these, and the motor 71 includes a motor shaft 71A and an electromagnetic solenoid 71B. It is composed of However, the motor 71 is for rotating the planet carrier 65 within a predetermined angle range.

  A motor shaft 71A as a sun gear is provided at the rear end of the drive shaft 2 at a position slightly coaxial with the drive shaft 2 at a distance from the bolt 27, and the gear 72 provided at the front end of the motor shaft 71A and the planet pinion 64 are engaged with each other. A ring gear is located on the outer periphery of the planet pinion 64. This ring gear is provided integrally with the motor housing 66.

  The planet carrier 65 of the second planetary gear mechanism 63 is the same as the planet carrier 26 of the first planetary gear mechanism 62. That is, the planet carrier 26 of the first planetary gear mechanism 62 includes an extending portion 26C extending in the direction orthogonal to the drive shaft 2 along the ring gear 24, and the sun gear 23 and the ring gear 24 from the extending portion 26C. An extended portion 26D extending to the rear end of the sprocket 31 toward the rear end in the drive axis direction and an extended portion 26E slightly spaced from the drive shaft 2 in a direction perpendicular to the drive shaft 2 from the extended portion 26D are continuous. The planet carrier 65 of the second planetary gear mechanism 63 is fixed to the extended portion 26E.

  When the electromagnetic solenoid 71B is not energized, the planet carrier 65 of the second planetary gear mechanism 63 and, therefore, the planet carrier 26 of the first planetary gear mechanism 62 are fixed. On the other hand, when the electromagnetic solenoid 71B is energized, the planet carrier 65 of the second planetary gear mechanism 63 rotates a predetermined angle about the motor shaft 71A. Then, the planet carrier 26 of the first planetary gear mechanism 62 rotates by the same amount as the planet carrier 65 of the second planetary gear mechanism 63, and the phase of the drive shaft 2 (cam shaft) with respect to the crankshaft changes. That is, the rotation amount of the planet carrier 26 is controlled by the motor 71, and the motor 71 is controlled by a control signal from the engine control unit 19.

The method of providing a mechanical stopper for the phase variable mechanism 61 and the control shaft 12 configured as described above is the same as in the first reference example . In FIG. 10, no space is provided between the chain case 73 and the upper surface of the ring gear 24 of the first planetary gear mechanism 62, but actually, an appropriate space is provided between the chain case 73 and the upper surface of the ring gear 24. A ring-shaped member 36 having the protrusion 36A (first stopper) described in the first reference example moves integrally with the planet carrier 26 in the same manner as described with reference to FIG. As described above, the ring-shaped member 36 having the protrusion 36 </ b> A (first stopper) is provided with respect to the planet carrier 26. On the other hand, as described in the first reference example , the disc-shaped member 38 is fixed to the rear end portion of the control shaft 12, and a pin 39 (second stopper) protruding rearward of the disc-shaped member 38 is disc-shaped. It is provided eccentric from the axis of the member 38.

Second, by the third reference example, the same effect as the first reference example is obtained.

Next, FIGS. 11 and 12 are schematic sectional views of the phase variable mechanisms 81 and 101 according to the first and second embodiments of the present invention, which replace FIG. 3 of the first reference example .

In the first embodiment, the phase variable mechanism 81 includes a differential gear device 82 including two side gears, two pinionmates, a carrier, and a ring gear, and an actuator 91 that can advance and retard the phase of the lift center angle of the intake valve. By fixing the ring gear, the power from the crankshaft of the engine is transmitted to the drive shaft 2 (cam shaft) through the differential gear device 82, and the speed is reduced by the differential gear device 82. Is used to reduce the rotational speed of the drive shaft 2 (cam shaft) to half of the rotational speed of the crankshaft, and the mechanical stopper of the present invention is provided for the phase variable mechanism 81 and the control shaft 12.

Similarly, in the second embodiment, the phase varying mechanism 101 is made to advance and retard the phase of the lift central angle of the intake valve and the differential gear device 102 including two side gears, two pinionmates, a carrier, and a ring gear. And an actuator (93) that can be operated, and by fixing one side gear, the power from the crankshaft of the engine is transmitted to the drive shaft 2 (camshaft) via the differential gear device 102, and The rotational speed of the drive shaft 2 (cam shaft) is reduced to half of the rotational speed of the crankshaft by using the speed reduction by the differential gear device 102. Further, the mechanical mechanism of the present invention is applied to the phase variable mechanism 101 and the control shaft 12. A stopper is provided.

First, referring to FIG. 11 of the first embodiment, the differential gear device 82 supports two pinionmates 83 and 84 positioned in the vertical direction in the figure, and supports these two pinionmates 83 and 84 as a whole. Is composed of a carrier 85 formed in a ring shape (abbreviated in the form of a rod in the figure) and two side gears 86 and 87 that mesh with the pinion mats 83 and 84, respectively.

In this case, in the first embodiment, one side gear 86 is fixed to the rear end of the drive shaft 2, a sprocket 88 is fixed to the other side gear 87, and a chain 89 is hung on the sprocket 88 and a crank sprocket (not shown). The sprocket 88 is rotated by the crankshaft.

  A gear 92 is meshed with a ring gear 90 provided on the outer periphery of the carrier 85, and the gear 92 is attached to a motor shaft 93 </ b> A of the motor 93. The motor 93 is for rotating the carrier 85 within a predetermined angle range. That is, the gear 92 and the motor 93 constitute a phase control actuator 91.

  The carrier 85 is fixed when the motor 93 is not energized. At this time, the phase of the drive shaft 2 (cam shaft) with respect to the crankshaft is determined. The rotational force from the crankshaft is transmitted in the order of the sprocket 88, the side gear 87, the pinion mats 83 and 84, the side gear 86, and the drive shaft 2. Therefore, by adjusting the number of teeth of the sprocket 88, the side gear 87, the pinion mats 83 and 84, and the side gear 86, the drive shaft 2 can be rotated at a half rotation speed of the crankshaft.

  On the other hand, by energizing the motor 93 and rotating the carrier 85 by a predetermined angle, the phase of the drive shaft 2 with respect to the crankshaft changes. That is, the rotation amount of the carrier 85 is controlled by the motor 93, and the motor 93 is controlled by a control signal from the engine control unit 19.

  The mechanical stopper of the present invention is provided for the phase variable mechanism 81 and the control shaft 12 configured as described above as follows. That is, a disc-like member 94 having a projection 94A (first stopper) equivalent to that shown in FIG. 8 is attached to the rear end of the gear 92 coaxially with the motor shaft 93A. On the other hand, a disc-like member 95 having a projection 95A (second stopper) equivalent to that shown in FIG. Then, in any combination of the phase of the lift center angle of the intake valve and the lift / operation angle of the intake valve, the two protrusions 94A and 95A are in contact with each other before the intake valve and the piston interfere with each other. The positions and shapes of the two protrusions 94A and 95A are set.

Next, FIG. 12 of the second embodiment will be described. In the second embodiment, the sprocket 103 is fixed to the outer periphery of the carrier 85, the chain 104 is hung around the sprocket 103 and a crank sprocket (not shown), and the sprocket 103 is rotationally driven by the crankshaft. Further, the side gear 87 and the shaft 93A of the motor 93 are fixed.

  The side gear 87 is fixed when the motor 93 is not energized. At this time, the phase of the drive shaft 2 (cam shaft) with respect to the crankshaft is determined. The rotational force from the crankshaft is transmitted in the order of the sprocket 104, the carrier 85, the pinion mats 86 and 87, the side gear 86, and the drive shaft 2. Therefore, by adjusting the number of teeth of the sprocket 104, the carrier 85, the pinion mats 86 and 87, and the side gears 86 and 87, the drive shaft 2 can be rotated at a rotational speed that is 1/2 of the crankshaft.

  On the other hand, by energizing the motor 93 and rotating the side gear 87 by a predetermined angle, the phase of the drive shaft 2 with respect to the crankshaft changes. That is, the rotation amount of the side gear 87 is controlled by the motor 93, and the motor 93 is controlled by the control signal from the engine control unit 19.

  The mechanical stopper of the present invention is provided for the differential gear device 102 and the control shaft 12 configured as described above as follows. That is, the disc-shaped member 94 having the projection 94A (first stopper) equivalent to that shown in FIG. 8 is attached to the motor shaft 93A. On the other hand, a disc-like member 95 having a projection 95A (second stopper) equivalent to that shown in FIG. Then, in any combination of the phase of the lift center angle of the intake valve and the lift / operation angle of the intake valve, the two protrusions 94A and 95A are in contact with each other before the intake valve and the piston interfere with each other. The positions and shapes of the two protrusions 94A and 95A are set.

Also according to the first and second embodiments (the invention described in claim 1 ), the same effect as the first reference example can be obtained.

  In the embodiment, the case where the lift / operating angle variable mechanism and the phase variable mechanism are provided on the intake valve side has been described. However, the present invention is not limited thereto, and the lift / operating angle variable mechanism and the phase variable mechanism are provided on the exhaust valve side. The present invention can also be applied to a case where the lift / operating angle variable mechanism and the phase variable mechanism are provided on both the intake valve side and the exhaust valve side.

The perspective view of a variable valve apparatus. FIG. 3 is a schematic cross-sectional view of a lift / operating angle variable mechanism showing a state of minimum swing and maximum swing when the lift / operating angle of the intake valve is minimum. The schematic sectional drawing of the phase variable mechanism of a 1st reference example . The arrow line view seen in the AA line of FIG. The characteristic view which shows the operating range of a variable valve apparatus. The characteristic view which shows the operating range of a variable valve apparatus. Schematic explaining the profile of a mechanical stopper. Schematic explaining the profile of a mechanical stopper. The schematic sectional drawing of the phase variable mechanism of a 2nd reference example . The schematic sectional drawing of the phase variable mechanism of a 3rd reference example . The schematic sectional drawing of the phase variable mechanism of 1st Embodiment. The schematic sectional drawing of the phase variable mechanism of 2nd Embodiment.

Explanation of symbols

1 Lift / operating angle variable mechanism 2 Drive shaft (cam shaft)
12 Control shaft 13 Lift / Operating angle control actuator 21 Phase variable mechanism 22 Planetary gear mechanism 36 Ring-shaped member 36A Protrusion (first stopper)
38 Disc-shaped member 39 Pin (second stopper)
40 Disc-shaped member 40A Protrusion (second stopper)
41 phase control actuator 51 phase variable mechanism 52 planetary gear mechanism 61 phase variable mechanism 62 first planetary gear mechanism 63 second planetary gear mechanism 71 motor (phase control actuator)
81 Phase variable mechanism 82 Differential gear device 91 Phase control actuator 94 Disk-shaped member 94A Protrusion (first stopper)
95 Disc-shaped member 95A Protrusion (second stopper)

Claims (1)

A variable lift / operating angle mechanism capable of simultaneously and continuously expanding and reducing the lift / operating angle of at least one of the intake and exhaust valves;
A differential gear device including a side gear, a pinion mate, a carrier, and a ring gear, and an actuator that includes a cam shaft and that can advance and retard the phase of at least one lift center angle of the intake and exhaust valves. And a phase variable mechanism for moving the
By fixing one of the side gear and the ring gear, the power from the crankshaft of the engine is transmitted to the camshaft through the differential gear device, and the reduction by the differential gear device is used. The rotational speed of the camshaft is half of the rotational speed of the crankshaft,
A first stopper is provided integrally with the phase variable mechanism, and a second stopper is provided integrally with the lift / operating angle variable mechanism,
The first stopper approaches the second stopper as the phase of the lift center angle advances, and the second stopper approaches the first stopper as the lift / operation angle increases, and In any combination of the phase of the lift center angle and the lift / operating angle, the position of the two stoppers is set so that the two stoppers come into contact with each other before at least one of the intake and exhaust valves interferes with the piston. A variable valve operating device for an engine characterized by setting a shape.

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