JP5834958B2 - Lock mechanism of variable valve timing mechanism - Google Patents

Description

  The present invention relates to a lock mechanism for a variable valve timing mechanism.

  As a mechanism mounted on an on-board internal combustion engine, a variable valve timing mechanism that makes the valve timing of an engine valve (intake / exhaust valve) variable has been put into practical use. As such a variable valve timing mechanism, for example, a vane type variable valve timing mechanism as disclosed in Patent Document 1 is known.

  The vane type variable valve timing mechanism illustrated in FIG. 4 includes two rotating bodies: a vane rotor 1 fixed to a camshaft so as to be integrally rotatable and a housing 3 integrated with a cam sprocket 2. The cam sprocket 2 is drivingly connected via a chain to a crankshaft that is an engine output shaft.

  The vane rotor 1 includes a columnar rotor body 4 and a plurality of vanes 5 projecting on the outer periphery thereof. The housing 3 includes a cam sprocket 2, a substantially annular ring portion 6 whose back surface is covered by the cam sprocket 2, and a cover 7 that covers the front surface of the ring portion 6. Housed inside. The vane rotor 1 and the housing 3 are coaxially assembled so as to be relatively rotatable.

  On the inner periphery of the ring portion 6 of the housing 3, a plurality of recesses 8 that respectively accommodate the vanes 5 of the vane rotor 1 are formed. A recess 8 on the inner periphery of the ring portion 6 is partitioned into two oil chambers by a vane 5. Among these, the oil chamber formed in the camshaft rotating direction of the vane 5 is a retarded oil chamber 9 into which hydraulic pressure for rotating the vane rotor 1 relative to the housing 3 in the camshaft counter-rotating direction is introduced. It has become. The oil chamber formed in the camshaft counter-rotating direction of the vane 5 is an advance oil chamber 10 into which hydraulic pressure for rotating the vane rotor 1 relative to the housing 3 in the camshaft rotating direction is introduced. Yes.

  When oil is supplied to the advance oil chamber 10 and discharged from the retard oil chamber 9, the vane rotor 1 rotates relative to the housing 3 in the camshaft rotation direction due to the difference in oil pressure acting on both sides of the vane 5. Moved. As a result, the rotational phase of the camshaft fixed to the vane rotor 1 so as to be integrally rotatable is advanced, and the valve timing of the engine valve that is driven to open and close by the cam provided on the camshaft is advanced. On the other hand, when oil is supplied to the retarded oil chamber 9 and discharged from the advanced oil chamber 10, the vane rotor 1 rotates in the camshaft counter-rotating direction with respect to the housing 3 due to the difference in hydraulic pressure acting on both sides of the vane 5. Relative rotation. As a result, the rotational phase of the camshaft fixed to the vane rotor 1 so as to be integrally rotatable is retarded, and the valve timing of the engine valve that is driven to open and close by the cam provided on the camshaft is retarded. On the other hand, when the oil pressures in the oil chambers (9, 10) are balanced, the relative rotation of the vane rotor 1 with respect to the housing 3 and, consequently, the rotational phase of the camshaft is fixed, and the valve timing is kept constant.

  In such a vane type variable valve timing mechanism, when the internal combustion engine is started, oil is removed from both the oil chambers (9, 10), so that the valve timing cannot be maintained by hydraulic pressure. Therefore, the vane variable valve timing mechanism is provided with a lock mechanism that locks the relative rotation of the vane rotor 1 with respect to the housing 3 so that the valve timing can be maintained at an appropriate time even when the internal combustion engine is started. Has been.

  The lock mechanism includes an accommodation hole 11 formed in the vane 5 of the vane rotor 1, a lock pin 12 accommodated in the accommodation hole 11 so as to be able to advance and retreat, and a lock hole (not shown) formed in the cam sprocket 2. I have. The lock pin 12 is constantly urged by the spring 13 in the direction of fitting into the front end side, that is, the lock hole formed in the cam sprocket 2, and at the rear, that is, from the lock hole by the oil pressure of both oil chambers (9, 10). It is pressed in the direction of detachment. Therefore, the lock pin 12 protrudes to the tip side by the urging force of the spring 13 when starting the internal combustion engine in which the oil pressures of both oil chambers (9, 10) are released. The protruding lock pin 12 is engaged with the lock hole, so that the relative rotation of the vane rotor 1 with respect to the housing 3 is locked.

  By the way, in recent years, the vane type variable valve timing mechanism that realizes the operation of the internal combustion engine by the Atkinson cycle has been advanced by delaying the closing timing of the intake valve substantially from the intake bottom dead center. Yes. In such a vane type variable valve timing mechanism, when the valve timing of the intake valve is set to the most retarded angle, a sufficient compression ratio cannot be ensured and the start of the internal combustion engine may not be guaranteed. In view of this, such a variable valve timing mechanism employs a lock mechanism configured to lock the relative rotation of the vane rotor 1 with respect to the housing 3 at a position advanced by a certain angle from the most retarded phase. Such a lock mechanism is called an intermediate lock mechanism because it locks the relative rotation at a phase intermediate between the most advanced angle phase and the most retarded angle phase.

  In the variable valve timing mechanism provided with the intermediate lock mechanism, the operation of the intermediate lock mechanism fails when the internal combustion engine is stopped, and the lock pin of the intermediate lock mechanism comes out of the lock hole when the internal combustion engine starts. May have. In such a case, when starting the internal combustion engine, it is necessary to quickly rotate the vane rotor 1 to the intermediate lock phase, and to lock the relative rotation of the vane rotor 1 with respect to the housing 3 by the intermediate lock mechanism.

  The rotation of the vane rotor 1 at this time is realized by providing the following latch grooves on the lock hole forming surface of the housing 3 of the variable valve timing mechanism. The latch groove is an arc-shaped groove that starts from the lock hole and extends in the counter-rotating direction of the camshaft, and is formed so that the groove depth becomes shallower as the distance from the lock hole increases. In the following description, a portion where the groove depth of the latch groove is the shallowest is referred to as the first stage of the latch groove, and a part where the groove depth is next shallow is referred to as the second stage of the latch groove.

  The rotation of the vane rotor 1 to the intermediate lock phase using such a latch groove is performed in the following manner. A reaction force accompanying the opening / closing drive of the engine valve by the cam, that is, a cam drive reaction force acts on the rotating camshaft, and such a cam drive reaction force also acts on the vane rotor 1 during rotation of the camshaft. Therefore, the vane rotor 1 swings with respect to the housing 3 by such a cam drive reaction force in a state where the oil pressures of both the oil chambers (9, 10) are released. Then, when the vane rotor 1 rotates by a certain amount with respect to the housing 3 by such swinging, the lock pin 12 is fitted into the first stage of the latch groove. When the lock pin 12 is inserted into the first stage of the latch groove in this way, the rotation of the vane rotor 1 to the retard side is restricted by the step at the end of the latch groove on the retard side, so that the vane rotor 1 swings. The range is a range on the advance side with respect to the end on the retard side of the first stage of the latch groove. From there, the vane rotor 1 rotates to the advance side by a certain amount with respect to the housing 3, and when the lock pin 12 is inserted into the second stage of the latch groove, the rotation of the vane rotor 1 to the retard side is latched. Since it is regulated by the step between the second stage and the first stage of the groove, the swinging range of the vane rotor 1 is a range on the advance side with respect to the retard side end of the second stage of the latch groove. . Thereafter, similarly, the lock pin 12 is sequentially inserted into a step where the depth of the latch groove is deep, and the swing range of the vane rotor 1 gradually moves to the advance side. Finally, the vane rotor 1 is rotated to the intermediate lock phase.

  In order to quickly and reliably rotate the vane rotor 1 to such an intermediate lock phase, the vane rotor 1 needs to be smoothly swung without being restricted by the cam drive reaction force. Here, when the retard oil chamber 9 and the advance oil chamber 10 are completely shut off, the volume of the advance oil chamber 10 increases as the vane rotor 1 swings toward the advance side. As a result, a negative pressure is generated in the advance oil chamber 10 to prevent the vane rotor 1 from swinging. In addition, when both oil chambers (9, 10) are filled with oil, the oil is compressed in accordance with the reduction in the volume of the oil chamber (9, 10) according to the swing of the vane rotor 1. Also, the vane rotor 1 is prevented from swinging. For this reason, in order to sufficiently ensure the mobility of the vane rotor 1, it is desirable to connect the oil chambers (9, 10) at this time.

Therefore, as a mechanism for realizing such communication between the oil chambers (9, 10), a lock mechanism having a double pin structure as shown in FIG. 5 is considered.
As shown in the drawing, one of the vanes 5 of the vane rotor 1 is formed with an accommodation hole 20 penetrating the vane 5. The accommodation hole 20 accommodates two pins, an inner pin 21 and an outer pin 22.

  On the other hand, the cam sprocket 2 constituting the housing 3 of the variable valve timing mechanism is formed with a lock groove 35 extending in the circumferential direction. A lock hole 36 whose depth is increased by one step is formed in the middle of the lock groove 35. The lock hole 36 is formed at a position overlapping the inner pin 21 when the vane rotor 1 is rotated to an intermediate lock phase set in the middle of the relative rotation range of the vane rotor 1 and the housing 3. The inner pin 21 is engaged with the lock hole 36, so that the relative rotation between the vane rotor 1 and the housing 3 is locked.

  The inner pin 21 is formed in a substantially hollow cylindrical shape in which a through hole 21a penetrating in the axial direction is formed. And the outer pin 22 formed in the substantially annular | circular shape is extrapolated by the outer periphery so that it can slide to an axial direction. A convex portion 32 protruding in the circumferential direction is formed on the outer periphery at the center in the axial direction of the inner pin 21, and sliding of the outer pin 22 toward the base end side with respect to the inner pin 21 is in contact with the convex portion 32. It is locked by contact.

  A substantially cylindrical guide bush 23 is fixed to the opening of the accommodation hole 20 on the proximal end side of the inner pin 21 by press-fitting. An annular ring bush 25 having a circular hole 24 formed at the center thereof through which the tip of the inner pin 21 can pass is fixed by press-fitting to the opening of the accommodation hole 20 on the tip side of the inner pin 21. The guide bushes 23 and the ring bushes 25 close the openings at both ends, so that an accommodation space 26 for the inner pin 21 and the outer pin 22 is formed in the accommodation hole 20.

  The guide bush 23 has a guide hole 27 into which the proximal end portion of the inner pin 21 is inserted. The inner periphery of the guide hole 27 on the distal end side of the inner pin 21 is substantially equal to the outer diameter of the proximal end portion of the inner pin 21, and serves as a sliding contact surface 27 a that is in sliding contact with the outer periphery of the inner pin 21. On the other hand, the inner periphery of the guide hole 27 on the proximal end side of the inner pin 21 is made larger than the outer diameter of the proximal end portion of the inner pin 21.

  An inner pin spring 28 is interposed between the inner pin 21 and the guide bush 23. The inner pin 21 is constantly urged toward the distal end side by the inner pin spring 28. An outer pin spring 29 is interposed between the outer pin 22 and the guide bush 23. The outer pin 22 is constantly urged toward the distal end side of the inner pin 21 by the outer pin spring 29.

  On the other hand, an outer pin releasing oil chamber 30 is defined between the outer pin 22 and the ring bush 25 in the accommodation hole 20. An outer pin releasing oil passage 31 is connected to the outer pin releasing oil chamber 30. And, the outer pin 22 is released to the outer pin releasing oil chamber 30 through the outer pin releasing oil passage 31, that is, the outer pin 22 is put on the proximal end side of the inner pin 21 against the urging force of the outer pin spring 29. Hydraulic pressure for displacement is introduced. When the outer pin 22 is retracted with the inner pin 21 displaced toward the tip side, the convex portion 32 formed on the outer periphery of the inner pin 21 comes into contact with the inner periphery of the outer pin 22, and the inner pin 21 is Along with the pins 22, the pins 22 are retracted to the base end side.

  Further, oil chamber communication passages 33 and 34 communicating with the retard oil chamber 9 and the advance oil chamber 10 of the variable valve timing mechanism are connected to the side periphery of the accommodation hole 20. The opening in the side periphery of the accommodation hole 20 of the oil chamber communication passages 33 and 34 is closed by the outer pin 22 when the outer pin 22 is retracted to the proximal end side of the inner pin 21.

Next, the operation of such a double pin structure locking mechanism will be described.
At the start of starting the internal combustion engine, the outer pin releasing oil chamber 30 is in a state in which oil has been removed, and the outer pin 22 has been advanced toward the distal end side of the inner pin 21 by the urging force of the outer pin spring 29. Therefore, the oil chamber communication passages 33 and 34 at this time are communicated with each other through the accommodation hole 20. As a result, the retard oil chamber 9 and the advance oil chamber 10 of the variable valve timing mechanism are communicated with each other, and the smooth swing of the vane rotor 1 is allowed.

  Thereafter, when the vane rotor 1 rotates to the intermediate lock phase through repeated swinging by the cam drive reaction force, the inner pin 21 is fitted into the lock hole by the urging force of the inner pin spring 28, and the vane rotor 1 and the housing 3 Relative rotation is locked. In this state, the internal combustion engine is started.

  When starting the variable control of the valve timing after starting the internal combustion engine, the hydraulic pressure is supplied to the outer pin releasing oil chamber 30 and the outer pin is resisted against the urging force of the outer pin spring 29 as shown in FIG. The pin 22 is retracted to the proximal end side of the inner pin 21. Thereby, the opening of the oil chamber communication passages 33 and 34 on the side periphery of the accommodation hole 20 is closed by the outer pin 22, and the communication between the retarded oil chamber 9 and the advanced oil chamber 10 of the variable valve timing mechanism is blocked. The Further, the inner pin 21 at this time moves backward together with the outer pin 22 and is detached from the lock hole. As a result, the relative rotation between the vane rotor 1 and the housing 3, that is, the change of the valve timing of the engine valve is allowed.

JP 2006-009694 A Japanese Patent Laid-Open No. 10-159521 JP 2002-256825 A

  By the way, in such a lock mechanism with a double pin structure, foreign matter mixed in the oil may enter the sliding portion between the inner pin 21 and the guide hole 27 and bite. In such a case, the smooth operation of the inner pin 21 is hindered, resulting in malfunction of the lock mechanism.

  Incidentally, conventionally, as can be seen in Patent Documents 2 and 3, in a variable valve timing mechanism having a lock mechanism with a single pin structure, a portion on the back side of the lock pin of the accommodation hole for accommodating the lock pin and a variable valve timing mechanism Providing a drain hole that directly communicates with the outside is proposed. If such a drain hole is provided, oil containing foreign matter is discharged to the outside from the back side of the lock pin.

  Therefore, even in the lock mechanism having the double pin structure as described above, a drain hole that directly communicates the rear side portion of the inner pin 21 of the guide hole 27 formed in the guide bush 23 to the outside of the variable valve timing mechanism is formed. Then, foreign matter is discharged through the drain hole, so that foreign matter can be prevented from entering the sliding contact portion between the guide hole 27 and the inner pin 21. However, in order to reliably prevent foreign matter from entering the sliding contact portion, it is necessary to make the oil flow resistance when passing through the drain hole sufficiently smaller than the oil flow resistance when passing through the sliding contact portion. It is necessary to increase the flow path area to some extent.

  Here, the double pin structure locking mechanism as described above has a structure in which the back side portion of the inner pin 21 of the guide hole 27 is not sealed because of the through hole 21 a formed in the inner pin 21. Yes. Therefore, if the drain hole as described above is provided, the oil always leaks to the outside through the drain hole, and the amount of oil leakage increases greatly.

  The present invention has been made in view of such circumstances, and the problem to be solved is to suitably suppress the malfunction of the lock mechanism due to the biting of foreign matter in the oil while suppressing an increase in the amount of oil leak. An object of the present invention is to provide a lock mechanism for a variable valve timing mechanism that can be used.

  The lock mechanism of the variable valve timing mechanism according to the present invention is configured to rotate in synchronism with one and the other of the engine output shaft and the cam shaft, respectively, and have a first axis and a second axis that are coaxially arranged and relatively rotatable. A variable valve timing mechanism including a rotating body is provided. Then, the relative rotation of the first and second rotating bodies is locked by engaging the tip of the lock pin disposed in the second rotating body with the lock hole formed in the first rotating body. It is configured as follows.

Furthermore, the locking mechanism of the variable valve timing mechanism of the present invention, in order to solve the above problems, a housing hole formed in the second rotary member, the opening of the base end side of the locking pin of the housing hole is closed together form a housing space and the guide hole of the lock pin receiving hole, and Ruga id bushing having a periphery in sliding contact with the sliding surface of the locking pin are bulged toward the center axis of the guide hole, In addition, a communication hole that connects the inside of the guide hole on the base end side of the lock pin with respect to the sliding contact surface and the outside of the guide hole in the accommodation space is formed in the guide bush.

  In such a configuration, the oil inside the guide hole on the base end side of the lock pin flows to the outside of the guide hole in the accommodation space through the communication hole. Therefore, the entry of foreign matter in the oil into the sliding contact portion between the lock pin and the guide hole can be suppressed. Moreover, since the communication hole is not directly communicated with the outside of the variable valve timing mechanism, the flow passage area of the communication hole can be increased while suppressing an increase in the amount of oil leakage. Therefore, according to the above configuration, it is possible to suitably suppress the malfunction of the lock mechanism due to the inclusion of foreign matter in the oil while suppressing an increase in the amount of oil leak.

It has been confirmed that foreign matters in the oil accumulate in the gap between the inner periphery of the guide hole and the outer periphery of the lock pin on the proximal end side of the lock pin with respect to the sliding contact surface. Therefore, if a communication hole is formed so as to extend in the radial direction of the guide hole from the inner periphery of the guide pin on the base end side of the lock pin with respect to the sliding contact surface, foreign matter accumulated in the gap is more accurately eliminated. This makes it possible to more reliably suppress malfunctions of the lock mechanism due to the inclusion of foreign matter in the oil.
In addition, a cross-sectional area of a surface perpendicular to the axial direction of the lock pin in the communication hole and extending in the communication hole is formed between the sliding contact surface and a portion of the lock pin facing the sliding contact surface. If the oil is configured to be larger than the cross-sectional area of the surface in the radial direction of the guide hole in the gap and perpendicular to the axial direction of the lock pin , the oil passes outside the guide hole through the communication hole having a smaller flow resistance than the gap. It becomes easy to leak. That is, it is possible to more suitably suppress the entry of foreign matter in oil into the sliding contact portion between the lock pin and the guide hole.

  Further, in order to discharge foreign matter to the outside of the variable valve timing mechanism, it is preferable to provide a drain passage that communicates the outside of the guide hole of the accommodation space with the outside of the variable valve timing mechanism. To ensure that foreign matter in the oil does not enter the sliding contact portion between the lock pin and the guide hole, the flow passage area of the communication hole must be increased so that the oil faces the communication hole instead of the sliding contact portion. Don't be. On the other hand, the drain passage does not need to have an excessively large flow path area as long as foreign matter can be discharged. Therefore, it is possible to suppress an increase in the amount of oil leak while discharging foreign matter to the outside of the variable valve timing mechanism.

  Incidentally, the lock mechanism of the variable valve timing mechanism of the present invention includes, for example, an annular outer pin that is externally inserted into the lock pin, and the lock pin is based on the displacement of the outer pin toward the lock pin proximal end side. It can be configured as a double pin structure locking mechanism that is displaced to the end side. Further, the lock mechanism of the variable valve timing mechanism of the present invention can be embodied as an intermediate lock mechanism that locks the two relative rotations in the middle of the relative rotation range of the first and second rotating bodies. It is.

Sectional drawing which shows the side part cross-section of the locking mechanism about one Embodiment which actualized the locking mechanism of the variable valve timing mechanism of this invention. Sectional drawing which expands and shows the part shown by II of FIG. Sectional drawing which shows the side part cross-section of the locking mechanism in the middle of the lock release of the embodiment. The fragmentary sectional view of a vane type variable valve timing mechanism. Sectional drawing which shows the side part cross-section of the locking mechanism of a double pin structure. Sectional drawing which shows the side part sectional structure at the time of lock release of the locking mechanism of the double pin structure.

Hereinafter, an embodiment embodying the lock mechanism of the variable valve timing mechanism of the present invention will be described in detail with reference to FIGS.
First, the configuration of the lock mechanism of the variable valve timing mechanism of the present embodiment will be described with reference to FIGS.

  The variable valve timing mechanism to which the locking mechanism of the present embodiment is applied has the same configuration as that shown in FIG. 4 except for the configuration of the locking mechanism. That is, the variable valve timing mechanism to which the present embodiment is applied rotates in synchronization with one and the other of the engine output shaft and the cam shaft, respectively, and has a housing 3 disposed coaxially and relatively rotatable. The two rotors of the vane rotor 1 are provided, and the valve timing of the engine valve is made variable through relative rotation thereof.

  In the variable valve timing mechanism, the lock mechanism according to the present embodiment is configured to perform an intermediate lock that locks the two relative rotations in the middle of the relative rotation range of the vane rotor 1 and the housing 3. ing. Further, the lock mechanism of the present embodiment is configured as a double pin structure lock mechanism including an inner pin and an outer pin, and the basic configuration is the same as that shown in FIG. . That is, as shown in FIG. 1, the lock mechanism of the present embodiment includes an inner pin 21 and an annular outer pin 22 that is externally inserted into the inner pin 21, and the inner pin 21 of the outer pin 22 The inner pin 21 is configured as a lock mechanism having a double pin structure in which the inner pin 21 is displaced toward the proximal end in accordance with the displacement toward the proximal end. Then, the relative rotation between the vane rotor 1 and the housing 3 is locked by engaging the tip of the inner pin 21 with a lock hole 36 formed in the cam sprocket 2 constituting the housing 3. .

  In addition, as described above, in such a lock mechanism, the opening on the proximal end side of the inner pin 21 in the accommodation hole 20 formed in the vane rotor 1 is closed by the guide bush 23, so that the inner pin 21 is inserted into the accommodation hole 20. A storage space 26 is formed. The guide bush 23 is formed with a guide hole 27 having a sliding contact surface 27 a that is in sliding contact with the outer periphery of the inner pin 21.

  In such a locking mechanism, the inner diameter of the guide hole 27 on the proximal end side of the inner pin 21 relative to the sliding contact surface 27a is made larger than the outer diameter of the proximal end portion of the inner pin 21. A gap S is formed between the inner periphery of the inner pin 21 and the outer periphery of the inner pin 21. In such a locking mechanism, it has been confirmed that foreign matter in the oil accumulates in the gap S.

  Therefore, in the present embodiment, by forming a discharge path for foreign matter accumulated in the gap S, entry of foreign matter into the sliding contact portion between the inner pin 21 and the guide hole 27 is suppressed. That is, in the lock mechanism of the variable valve timing mechanism of the present embodiment, as shown in FIG. 2, a communication hole 37 that connects the inside of the guide hole 27 and the outside of the guide hole 27 of the accommodation space 26 is formed in the guide bush 23. Forming. The communication hole 37 extends in the radial direction of the guide bush 23 from the inner periphery of the guide hole 27 on the proximal side of the sliding contact surface 27 a with the inner pin 21. The cross-sectional area of the communication hole 37 (oil passage area) is sufficiently larger than the cross-sectional area of the gap between the sliding contact portions of the inner pin 21 and the guide hole 27.

  Further, a groove extending in the axial direction is formed on the inner periphery of the accommodation hole 20 on the proximal end side of the inner pin 21. The groove forms a drain passage 38 that passes through the fitting portion between the accommodation hole 20 and the guide bush 23 and communicates the outside of the guide hole 27 of the accommodation space 26 with the outside of the variable valve timing mechanism. The drain passage 38 is formed so that its cross-sectional area (oil passage area) is smaller than that of the communication hole 37. Incidentally, the drain passage 38 is formed so that the opening to the accommodation space 26 faces the opening of the communication hole 37 on the outer periphery of the guide bush 23.

Next, the operation of the lock mechanism of the variable valve timing mechanism of this embodiment will be described.
At the time of unlocking, the unlocking hydraulic pressure is introduced into the outer pin releasing oil chamber 30 through the outer pin releasing oil passage 31, whereby the outer pin 22 is displaced together with the inner pin 21 to the proximal end side. Note that hydraulic pressure is introduced into both the retard oil chamber 9 and the advance oil chamber 10 at this time in order to restrict the rotation of the vane rotor 1 after unlocking.

  As shown in FIG. 3, during such unlocking, oil flows from the retarded oil chamber 9 through the through hole 21 a formed in the inner pin 21 into the rear portion of the inner pin 21 of the guide hole 27. To do. Therefore, the hydraulic pressure at the rear portion of the inner pin 21 of the guide hole 27 is higher than the hydraulic pressure outside the guide hole 27 of the accommodation space 26 that is at atmospheric pressure because it is opened to the atmosphere through the drain passage 38.

  At this time, in the present embodiment, the communication hole 37 is formed so that the cross-sectional area is larger than the gap of the sliding contact portion between the inner pin 21 and the guide hole 27. Therefore, such oil flows out of the guide hole 27 of the accommodation space 26 through the communication hole 37 having a smaller flow resistance. The oil that has flowed into the outside of the guide hole 27 of the accommodation space 26 is discharged to the outside of the variable valve timing mechanism through the drain passage 38. At this time, the foreign matter accumulated in the gap S is pushed away by such a flow of oil and discharged to the outside of the variable valve timing mechanism together with the oil.

  During locking, the inner pin 21 comes into contact with the tip of the inner pin 21 and the bottom surface of the lock hole 36. After unlocking, the inner pin 21 comes into contact with the base end of the inner pin 21 and the bottom surface of the guide hole 27. The flow of oil through the through-hole 21a is blocked. Therefore, the outflow of oil to the outside through the communication hole 37 and the drain passage 38 is limited to the middle of unlocking, and the increase in the amount of oil leak is limited by the formation of the communication hole 37.

  Incidentally, in this embodiment, the housing 3 corresponds to the first rotating body in the present invention, and the vane rotor 1 corresponds to the second rotating body in the present invention. Moreover, in this Embodiment, the inner pin 21 becomes a structure corresponding to the lock pin in this invention.

According to the lock mechanism of the variable valve timing mechanism of the present embodiment described above, the following effects can be achieved.
(1) In the present embodiment, the communication hole 37 that communicates the inside of the guide hole 27 and the outside of the guide hole 27 in the accommodation space 26 on the proximal side of the sliding contact surface 27 a with the outer periphery of the inner pin 21 is guided. The bush 23 is formed. Therefore, entry of foreign matter in oil into the sliding contact portion between the inner pin 21 and the guide hole 27 is suppressed. Moreover, since the communication hole 37 is not directly communicated with the outside of the variable valve timing mechanism, the flow passage area of the communication hole 37 can be increased while suppressing an increase in the amount of oil leak. Therefore, according to the present embodiment, it is possible to suitably suppress the malfunction of the lock mechanism due to the inclusion of foreign matter in the oil while suppressing an increase in the amount of oil leak.

  (2) In the present embodiment, the communication hole 37 is formed so as to extend in the radial direction of the guide hole 27 from the inner periphery of the guide hole 27 on the proximal end side with respect to the sliding contact surface 27a. For this reason, it is possible to more accurately eliminate the foreign matter accumulated in the gap S between the inner periphery of the guide hole 27 and the outer periphery of the inner pin 21 on the base end side with respect to the sliding contact surface 27a. The malfunction of the lock mechanism can be suppressed more reliably.

  (3) In the present embodiment, since the drain passage 38 that communicates the outside of the guide hole 27 of the accommodation space 26 and the outside of the variable valve timing mechanism is provided, foreign matter in the oil can be excluded to the outside. it can. In order to prevent oil from flowing into the sliding contact portion between the inner pin 21 and the guide hole 27, the flow passage area of the drain passage 38 needs to be excessively large, unlike the communication hole 37 that requires a large flow passage area. Therefore, it is possible to suppress an increase in the amount of oil leak by adopting a structure in which foreign matter in the oil is discharged to the outside via the accommodation space 26.

In addition, the said embodiment can also be changed and implemented as follows.
In the above-described embodiment, the opening of the drain passage 38 with respect to the accommodation space 26 is opposed to the opening of the communication hole 37 on the outer periphery of the guide bush 23. A configuration in which the positions of both openings are shifted may be employed.

  In the above configuration, the drain passage 38 is formed by forming a groove in the inner periphery of the accommodation hole 20, but the accommodation space 26 and the variable valve can be formed by other methods such as making a hole in the vane 5. A drain passage communicating with the outside of the timing mechanism may be formed.

  In the above configuration, the foreign space is finally discharged to the outside of the variable valve timing mechanism by communicating the accommodating space 26 to the outside through the drain passage 38. Foreign substances excluded may be collected in a space formed in the variable valve timing mechanism or the like.

  In the above embodiment, the communication hole 37 is formed so as to extend in the radial direction of the guide hole 27 from the inner periphery of the guide hole 27 on the proximal end side of the inner pin 21 relative to the sliding contact surface 27a. However, the communication hole is formed so that the inside of the guide hole 27 on the base end side of the inner pin 21 with respect to the sliding contact surface 27a communicates with the outside of the guide hole 27 of the accommodation space 26 and the oil flow resistance is sufficiently small. If formed, it is possible to suppress biting of foreign matter into the sliding contact portion between the inner pin 21 and the guide hole 27 while suppressing an increase in the amount of oil leak.

  In the above embodiment, the example in which the present invention is embodied as an intermediate lock mechanism that locks the relative rotation of the vane rotor 1 and the housing 3 in the middle of the relative rotation range has been described. Can also be implemented as a lock mechanism that locks the relative rotation at the end of the relative rotation range.

  In the above embodiment, an example in which the present invention is embodied as a lock mechanism having a double pin structure of the inner pin 21 and the outer pin 22 has been described, but the present invention is a lock having only a single lock pin. It can also be applied to mechanisms. The point is that the housing space for the lock pin is formed by closing the opening on the base end side of the lock pin of the housing hole, and the guide bush having the sliding hole surface that is in sliding contact with the outer periphery of the lock pin is provided. The present invention can be applied to any lock mechanism.

  In the above embodiment, a lock pin (inner pin 21) is provided on the rotating body (vane rotor 1) that rotates in synchronization with the camshaft, and a lock hole is provided on the rotating body (housing 3) that rotates in synchronization with the engine output shaft. 36 is provided. On the other hand, it is also possible to configure the lock mechanism such that a lock pin is provided in the rotating body that rotates synchronously with the engine output shaft, and a lock hole is provided in the rotating body that rotates synchronously with the camshaft. .

  DESCRIPTION OF SYMBOLS 1 ... Vane rotor (2nd rotary body: 4 ... Rotor main body, 5 ... Vane) 3 ... Housing (1st rotary body: 2 ... Cam sprocket, 6 ... Ring part, 7 ... Cover), 8 ... Recessed part, DESCRIPTION OF SYMBOLS 9 ... Retarded oil chamber, 10 ... Advance oil chamber, 11 ... Accommodating hole, 12 ... Lock pin, 13 ... Spring, 20 ... Accommodating hole, 21 ... Inner pin (lock pin), 21a ... Through-hole, 22 ... Outer Pins 23 ... Guide bushing 24 ... Round hole 25 ... Ring bush 26 ... Accommodating space 27 ... Guide hole 27a ... Sliding contact surface 28 ... Inner pin spring 29 ... Outer pin spring 30 ... Outer pin release Oil chamber 31... Outer pin release oil passage 32. Projection 33 33 Oil chamber communication passage 34 Oil chamber communication passage 35 Lock groove 36 Lock hole 37 Communication hole 38 Drain passage

Claims (3)

Provided in a variable valve timing mechanism comprising first and second rotating bodies that rotate synchronously with one and the other of the engine output shaft and the cam shaft and that are coaxially disposed so as to be relatively rotatable, The relative rotation of the first and second rotating bodies is locked by engaging the tip of a lock pin disposed on the second rotating body in a lock hole formed in the first rotating body. A locking mechanism,
Said second rotary member which is formed in the accommodation hole, an opening of the locking pin on the base end side of the accommodation hole forms a housing space and the guide hole of the lock pin in the housing bore is closed and Ruga id bushing having a periphery in sliding contact with the sliding surface of the locking pin are bulged toward the center axis of the guide hole, the outer and the variable valve timing mechanism of the guide hole of the housing space A drain passage communicating with the outside of the
A communication hole is formed in the guide bush for communicating the inside of the guide hole on the proximal end side of the lock pin with respect to the sliding contact surface and the outside of the guide hole in the housing space,
The communication hole is extended in the radial direction of the guide hole from the inner periphery of the guide hole on the proximal end side of the lock pin with respect to the sliding contact surface,
The cross-sectional area of the axial direction of the lock pin in the communication hole and perpendicular to the direction in which the communication hole extends is between the sliding contact surface and the portion of the locking pin facing the sliding contact surface. A lock mechanism for a variable valve timing mechanism, wherein the cross-sectional area of a surface perpendicular to the axial direction of the lock pin in the radial direction of the guide hole in the gap formed in the gap is larger. The lock mechanism includes an annular outer pin that is externally inserted into the lock pin, and the lock pin is displaced to the proximal end side in accordance with the displacement of the outer pin toward the proximal end side of the lock pin. The lock mechanism for a variable valve timing mechanism according to claim 1, wherein the lock mechanism is configured as a lock mechanism having a heavy pin structure. The lock mechanism of the variable valve timing mechanism according to claim 1 or 2 , wherein the lock mechanism latches the two relative rotations in the middle of the relative rotation range of the first and second rotating bodies.