CN112096476A

CN112096476A - Valve timing adjusting device

Info

Publication number: CN112096476A
Application number: CN202010472354.1A
Authority: CN
Inventors: 竹中健一郎; 福山智之
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2019-06-17
Filing date: 2020-05-29
Publication date: 2020-12-18
Also published as: DE102020109277A1; JP2020204282A

Abstract

The valve timing adjusting apparatus includes: a drive-side rotating body (300); a vane rotor (20); a locking device (80) configured to lock rotation of the vane rotor (20) relative to the housing. The locking device (80) comprises: a pin receiving portion (25) formed on the vane rotor; a recess (90) formed in the drive-side rolling body; a stopper pin (27) received in the pin receiving portion and configured to reciprocate along the pin receiving portion and the recess; a spring (28) configured to urge the stop pin. The recess has: a lower groove (91) configured to receive a retaining pin; an upper groove (92) circumferentially engages the lower groove and has a groove depth measured axially less than the groove depth measured axially of the lower groove. In a state where the distal end surface of the stopper pin is in contact with the upper groove, an upper groove peripheral portion (98) which is a portion where the outer periphery of the upper groove is not engaged with the lower groove is not opposed to the distal end portion of the stopper pin at a surface extending in the axial direction.

Description

Valve timing adjusting device

Technical Field

The present invention relates to a valve timing adjustment apparatus.

Background

Heretofore, a hydraulic valve timing adjusting apparatus configured to adjust the valve timing of an intake valve or an exhaust valve of an internal combustion engine has been known. One such valve timing adjusting apparatus includes a locking device that locks rotation of the vane rotor relative to a drive-side rolling body such as a housing. For example, the locking device of the valve timing adjusting apparatus described in WO/2012/086085a1 locks the rotation of the vane rotor with respect to the housing, i.e., the drive-side rolling body, when a stopper pin is inserted into a recess of the housing by the urging force of a spring in a state where the oil pressure is insufficient to hold the current rotational phase of the vane rotor. Further, when the stopper pin is removed from the recess in response to application of the oil pressure to the stopper pin, the lock is released.

In a state where the stopper pin is inserted into the recess of the driving-side rolling body, when a torque applied when the valve timing adjustment apparatus is connected to an end portion of a camshaft (as a driven-side shaft) or a torque of the camshaft when the internal combustion engine is driven is applied to the valve timing adjustment apparatus, the driving-side rolling body may be deformed in a thrust direction in response to a stress generated at the recess, possibly causing interference between the driving-side rolling body and the vane rotor. Further, in the case where the ring member is press-fitted to the recess to secure the required strength of the recess, the stress generated at the time of press-fitting the ring member to the recess may cause deformation of the drive-side rolling body to generate interference between the drive-side rolling body and the vane rotor. In the case where the recess includes a lower groove of a large groove depth and an upper groove of a small groove depth, like the recess of the valve timing adjusting apparatus of WO/2012/086085a1, when the drive-side rolling body is deformed in response to stress generated at the lower groove, interference between the drive-side rolling body and the vane rotor can be restricted. However, when releasing the lock, the stopper pin may be caught by the upper groove, thereby interfering with the release of the lock.

Disclosure of Invention

An object of the present invention is to provide a technique of restricting interference between a drive-side rolling body and a vane rotor, and restricting interference to release of locking of the vane rotor with respect to the drive-side rolling body.

According to the present invention, there is provided a valve timing adjusting apparatus to be fixed to an end portion of a driven-side shaft configured to receive a driving force from a driving-side shaft to open and close a valve, while the valve timing adjusting apparatus is configured to adjust a relative rotational phase of the driven-side shaft with respect to the driving-side shaft to adjust a valve timing of the valve. The valve timing adjusting apparatus includes: a drive-side rotating body having an internal space and configured to rotate in synchronization with the drive-side shaft; a vane rotor accommodated in an inner space of the driving-side rolling body and connected to the driven-side shaft, wherein the vane rotor includes a vane partitioning the inner space into a plurality of hydraulic chambers, and the vane rotor is configured to rotate relative to the driving-side rolling body when the vane receives a pressure of hydraulic oil introduced into one of the plurality of hydraulic chambers; and a locking device configured to lock rotation of the vane rotor with respect to the drive-side rolling body. The locking device includes: a pin receiving portion formed at the vane rotor and extending in an axial direction parallel to a rotational axis of the drive-side rolling body; a recess formed on the driving-side rolling body, the recess being configured to be opposed to the pin receiving portion; a stopper pin received in the pin receiving portion and configured to reciprocate in an axial direction along the pin receiving portion and the recess; and a spring configured to urge the stopper pin toward the recess. The recess has: an underside groove configured to receive a retaining pin; and an upper groove that is engaged with the lower groove in the circumferential direction and has a groove depth, and the groove depth of the upper groove measured in the axial direction is smaller than the groove depth of the lower groove measured in the axial direction. In a state where the distal end surface of the stopper pin is in contact with the upper groove, the upper groove peripheral portion, which is a portion of the upper groove periphery that is spaced from and thus not engaged with the lower groove, is not opposed to the distal end portion of the stopper pin at the axially extending surface.

In the above valve timing adjustment device, the recess portion includes: an underside groove configured to receive a retaining pin; and an upper groove engaged with the lower groove in a circumferential direction and having a groove depth, and the groove depth of the upper groove measured in the axial direction is smaller than the groove depth of the lower groove measured in the axial direction. Thus, when the driving side rolling body is deformed in response to the stress generated at the lower side groove, the interference between the driving side rolling body and the vane rotor can be restricted. In addition, in a state where the distal end surface of the stopper pin is in contact with the upper groove, the upper groove peripheral portion, which is a portion of the outer periphery of the upper groove that is not engaged with the lower groove, is not opposed to the distal end portion of the stopper pin at the surface extending in the axial direction. Therefore, when the lock is released, the stopper pin can be restricted from being caught by the upper groove outer peripheral portion. Therefore, interference between the drive-side rolling body and the vane rotor is restricted, and interference to release the lock is restricted.

The invention may be embodied in various other forms. For example, the invention may be realized as an internal combustion engine including a valve timing adjustment apparatus or a manufacturing method of the valve timing adjustment apparatus.

Drawings

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

Fig. 1 is a sectional view schematically showing the structure of a valve timing adjusting apparatus of an embodiment.

Fig. 2 is a sectional view taken along line II-II of fig. 1.

Fig. 3 is a perspective view schematically showing the structure of the housing.

Fig. 4 is a front view of the housing as viewed from the side where the camshaft is placed.

Fig. 5 is a sectional view mainly showing the hydraulic oil control valve.

Fig. 6 is an enlarged view showing a recess structure.

Fig. 7 is a sectional view schematically showing a cross section taken along the line VII-VII in fig. 6.

Fig. 8 is an explanatory diagram showing the first angle and the second angle.

Fig. 9 is an explanatory view schematically showing a recess manufacturing process.

Detailed Description

A. Examples of the embodiments

A-1. general structure:

a valve timing adjusting apparatus 100 according to an embodiment of the present invention shown in fig. 1 is mounted at a driving force transmission path extending from a crankshaft (as a driving-side shaft) to a camshaft (as a driven-side shaft) 200 at an internal combustion engine of a vehicle (not shown). Specifically, the valve timing adjustment apparatus 100 is fixed to an end of the camshaft 200. The valve timing adjustment apparatus 100 adjusts the valve timing of a valve (not shown) opened and closed by a camshaft 200. The rotation axis CX of the valve timing adjusting apparatus 100 coincides with the rotation axis CX of the camshaft 200. The valve timing adjusting apparatus 100 of the present embodiment adjusts the valve timing of the intake valve among the intake valve and the exhaust valve (serving as valves).

The valve timing adjusting apparatus 100 includes a pulley 10, a housing 40, a vane rotor 20, a bushing member 30, a front plate 50, a hydraulic oil control valve 60, and a locking device 80. The pulley 10, the housing 40, the vane rotor 20, the bushing member 30, the front plate 50, and the hydraulic oil control valve 60 each have a rotation axis CX coinciding with the rotation axis CX of the camshaft 200. In the present embodiment, a direction parallel to the rotation axis CX is referred to as an axial direction CR. The side of the valve timing adjustment apparatus 100 opposite to the side on which the camshaft 200 is placed in the axial direction CR is referred to as the rear side, and the side of the valve timing adjustment apparatus 100 opposite to the rear side in the axial direction CR is referred to as the front side. In the following description, the pulley 10 and the housing 40 will also be collectively referred to as a driving-side rolling body 300. The driving-side rolling body 300 rotates in synchronization with the crankshaft.

In fig. 1, in addition to the valve timing adjusting apparatus 100 and the camshaft 200, a solenoid 70, a solenoid cover 72, and a rear cover 290 are shown. The solenoid 70 includes a pushing pin 71, and the pushing pin 71 is driven in the axial direction CR by using an electromagnetic force generated when the solenoid 70 is energized by an Electronic Control Unit (ECU), not shown. In this way, the hydraulic oil control valve 60 is driven to control the flow of hydraulic oil. The solenoid cover 72 has a through hole 75 that receives a portion of the solenoid 70 on the rear side. The solenoid cover 72 also has a sealing portion 73 formed in a tubular shape. The seal portion 73 is placed around the through hole 75 and protrudes to the rear side. The rear cover 290 covers and extends entirely around the front side end of the camshaft 200.

The pulley 10 is formed in a substantially bottomed tubular shape. The pulley 10 includes: an external tooth portion 11 shaped like a tube; a flange portion 12; and a tubular portion 13. As shown in fig. 2, the external teeth portion 11 has a plurality of teeth that project outward in the radial direction and are arranged one after another all around the external teeth portion 11 in the circumferential direction of the external teeth portion 11. In the present embodiment, the radial direction refers to a direction perpendicular to the axial direction CR. A belt (not shown) is wound around the external teeth portions 11 to transmit the driving force of the crankshaft to the external teeth portions 11. The flange portion 12 shown in fig. 1 is shaped like a circular disk. The flange portion 12 engages with a rear end portion of the external teeth portion 11 and extends in the radial direction. A through hole is formed in the center of the flange 12. The tubular portion 13 is formed in a tubular shape and is coaxial with the external tooth portion 11. The front end of the tubular portion 13 is engaged with the flange portion 12 and communicates with the through hole of the flange portion 12. The camshaft 200 is received in a space formed on the radially inner side of the tubular portion 13. The rear cover 290 extends entirely around the rear side of the tubular portion 13 and covers the rear side of the tubular portion 13.

As shown in fig. 1 to 4, the case 40 is shaped like a bottomed tube, and a through hole extends through the bottom of the case 40. As shown in fig. 1, the housing 40 is received in a space located radially inward of the pulley 10 such that an opening portion of the housing 40 that opens to the rear side is opposed to a surface of the pulley 10 on the front side of the flange portion 12. The vane rotor 20 is received in a space located radially inside the casing 40, i.e., an inner space of the casing 40.

As shown in fig. 1, 3 and 4, the housing 40 includes a front wall portion 47 and a peripheral wall portion 41. The front wall portion 47 is formed substantially in a disk shape. The front wall portion 47 is located at the foremost side of the housing 40, and extends in a direction perpendicular to the axial direction CR. A through hole 45 having a circular cross section extends through a central portion of the front wall portion 47. A recess 90 is formed at the front wall portion 47, the recess 90 forming part of the locking device 80. Details of the recess 90 will be described later. The peripheral wall portion 41 is formed in a cylindrical shape and protrudes rearward from the outer peripheral edge of the front wall portion 47. The peripheral wall portion 41 has three partition wall portions 42 that protrude inward in the radial direction and are arranged one after another in the circumferential direction.

The vane rotor 20 shown in fig. 1 and 2 is received in the inner space of the housing 40. As shown in fig. 1, the vane rotor 20 is connected to the camshaft 200 through the hydraulic oil control valve 60 and the bushing member 30. When the vane rotor 20 rotates, the vane rotor 20 rotates the camshaft 200. In the present embodiment, the vane rotor 20 and the casing 40 are made of an aluminum alloy. As shown in fig. 2, the vane rotor 20 includes a rotor 21 and three vanes 22.

The rotor 21 is shaped substantially in a cylindrical tube shape and has a receiving hole 29 which is located at the center of the rotor 21 and extends in the axial direction CR. The blades 22 project radially outward from the rotor 21 and are arranged in succession in the circumferential direction. Each blade 22 is placed between corresponding adjacent two partition wall portions 42, the adjacent two partition wall portions 42 being adjacent to each other in the circumferential direction to partition the internal space of the casing 40 into a plurality of hydraulic chambers. Specifically, three spaces each defined in the circumferential direction between corresponding adjacent two partition wall portions 42 are partitioned into a retard chamber 43 and an advance chamber 44, respectively, the retard chamber 43 and the advance chamber 44 serving as oil pressure chambers by corresponding one of the vanes 22. Hydraulic oil is supplied to each retard chamber 43 or discharged from each retard chamber 43 through a corresponding retard oil passage 123 formed inside the vane rotor 20. Similarly, hydraulic oil is supplied to or discharged from each advance chamber 44 through a corresponding advance passage 124 formed inside the vane rotor 20. The vane rotor 20 rotates relative to the housing 40 in accordance with the oil pressure of the hydraulic oil supplied to the retard chamber 43 and the advance chamber 44.

One of the three blades 22 is formed to be larger than the other two of the blades 22. The large vane 22 has a pin receiving portion 25, the pin receiving portion 25 being in the form of a cylindrical recess extending in the axial direction CR. The pin receiving portion 25 forms part of the locking device 80. Details of the pin receiving portion 25 will be described later.

The bush member 30 shown in fig. 1 is formed in a cylindrical tube shape and has a through hole extending through the bush member 30 in the axial direction CR. The bushing member 30 is interposed between the housing 40 and the hydraulic oil control valve 60 and is thus radially placed between the housing 40 and the hydraulic oil control valve 60. The bushing member 30 serves as a bearing and rotatably supports the housing 40. The rear-side end of the bushing member 30 is fixed to the blade rotor 20 by press-fitting the rear-side end of the bushing member 30 to the blade rotor 20 and also by using the fixing pin 24. The remaining portion of the bushing member 30 other than the rear-side end is received in the through hole 45 of the housing 40.

The front plate 50 is formed substantially in a tubular shape. The front plate 50 is placed on the foremost side of the valve timing adjusting apparatus 100, and receives the end of the hydraulic oil control valve 60 on the front side. Further, the front side end portion of the front plate 50 is received inside the sealing portion 73 of the solenoid 70. The front plate 50 restricts leakage of hydraulic oil leaking from the clearance between the housing 40 and the bushing member 30 to the outside of the valve timing adjusting apparatus 100. The front plate 50 has a tubular portion 51 and a flange portion 52. The tubular portion 51 is shaped like a tube and receives an end portion of the hydraulic oil control valve 60 on the front side. A seal member 74 for restricting leakage of the hydraulic oil is interposed between the inner peripheral surface of the seal portion 73 and the outer peripheral surface of the front-side end portion of the tubular portion 51. The flange portion 52 is shaped like a disk and has a through hole penetrating the center portion of the flange portion 52. The flange portion 52 is engaged with the rear end portion of the tubular portion 51. The rear side surface of the flange portion 52 contacts the front side surface of the front wall portion 47 of the housing 40.

The front plate 50, the housing 40, and the pulley 10 are stacked in this order in the axial direction CR, and fixed together by the bolts 19. Thus, the front plate 50, the housing 40, and the pulley 10 rotate in synchronization with the crankshaft.

The hydraulic oil control valve 60 is a spool valve, and is disposed along the rotational axis CX of the valve timing adjusting apparatus 100. The hydraulic oil control valve 60 controls the supply of hydraulic oil to the retard chamber 43 or the advance chamber 44 shown in fig. 2 by using the driving force of the solenoid 70, and also controls the discharge of hydraulic oil from the retard chamber 43 or the advance chamber 44. Further, the hydraulic oil control valve 60 serves as a fixing element that fixes the vane rotor 20 to the camshaft 200.

As shown in fig. 1, hydraulic oil to be supplied to the hydraulic oil control valve 60 is stored in an oil pan 500. The oil pump 510 sucks hydraulic oil from the oil pan 500 and pumps out the sucked hydraulic oil to supply the hydraulic oil to the hydraulic oil supply passage 250 through the through hole 291 of the rear cover 290, which penetrates the peripheral wall of the rear cover 290 in the thickness direction (radial direction) of the peripheral wall of the rear cover 290, and the through hole 220 of the camshaft 200, which penetrates the peripheral wall of the camshaft 200 in the thickness direction (radial direction) of the peripheral wall of the camshaft 200. The hydraulic oil supply passage 250 is formed by a gap defined between the outer peripheral surface of the hydraulic oil control valve 60 and the inner peripheral surface of a receiving hole 201, the receiving hole 201 being formed at the front-side end portion of the camshaft 200. The hydraulic oil supplied to the hydraulic oil supply passage 250 is supplied to the retard chamber 43 or the advance chamber 44 through the hydraulic oil control valve 60. Further, a part of the hydraulic oil discharged from the retard chamber 43 or the advance chamber 44 is discharged to the oil pan 500 through the inside of the hydraulic oil control valve 60 and the discharge hole 230 formed inside the camshaft 200.

A portion of the hydraulic oil control valve 60 on the rear side in the axial direction CR is received in a receiving hole 201 formed at the camshaft 200. A central portion of the hydraulic oil control valve 60, which is centered in the axial direction CR, is received at the receiving hole 29 of the vane rotor 20 and radially inside the bushing member 30. The other portion of the hydraulic oil control valve 60 on the front side is received radially inside the tubular portion 51 of the front plate 50.

As shown in fig. 5, the hydraulic oil control valve 60 includes an outer sleeve 61, an inner sleeve 62, and a spool 63. The outer sleeve 61 and the inner sleeve 62 form a sleeve that slidably supports the spool 63 such that the spool 63 can reciprocate in the axial direction CR, and the sleeve fixes the vane rotor 20 to the camshaft 200.

The outer sleeve 61 is formed substantially in a cylindrical tubular shape. The outer sleeve 61 has a function of fixing the hydraulic oil control valve 60 to the camshaft 200, a function of receiving the inner sleeve 62 and the spool 63, and a function of forming the hydraulic oil supply passage 250. The outer sleeve 61 has a male screw portion 610 formed on the outer peripheral surface of the rear end portion thereof. The male screw portion 610 is threadedly engaged with a female screw portion 210 formed at a rear end portion of the receiving hole 201 of the camshaft 200. In this way, the hydraulic oil control valve 60 is firmly connected to the camshaft 200. With such a firm connection between the hydraulic oil control valve 60 and the camshaft 200, an axial force is exerted in the axial direction CR, so that a positional deviation between the hydraulic oil control valve 60 and the camshaft 200 can be restricted by an eccentric force of the camshaft 200 generated when the camshaft 200 rotates and pushes the intake valve. The front end of the outer sleeve 61 is formed with a tool engagement portion 613. The tool engagement portion 613 is shaped so that the tool engagement portion 613 can be engaged with a tool such as a socket head, and the tool engagement portion 613 is used when the hydraulic oil control valve 60 is connected to the camshaft 200.

A projection 614 is formed at the outer sleeve 61, and the projection 614 is placed at the rear side of the tool engaging portion 613 at a position adjacent to the tool engaging portion 613. The projection 614 is shaped in a flange shape and projects radially outward. When the hydraulic oil control valve 60 is firmly connected to the camshaft 200, the projection 614 pushes against the end face of the bush member 30 on the front side. Further, the bushing member 30 is pushed to the rear side by the projection 614, so that the hydraulic oil control valve 60 and the vane rotor 20 are firmly coupled together by the bushing member 30. Here, the hydraulic pressure control valve 60 is fixed to the camshaft 200. Therefore, when the bushing member 30 is pushed to the rear side by the projection 614, the camshaft 200 and the vane rotor 20 are firmly connected together by the bushing member 30 and the hydraulic oil control valve 60. The rear side end of the receiving hole 201 of the camshaft 200 communicates with the discharge hole 230. A hydraulic oil supply hole 615 is formed at the outer sleeve 61. The hydraulic oil supply hole 615 is in the form of a through hole, and extends through the peripheral wall of the outer sleeve 61 in the thickness direction (radial direction) of the peripheral wall of the outer sleeve 61. The hydraulic oil supply hole 615 supplies the hydraulic oil received through the hydraulic oil supply passage 250 to a space defined between the outer sleeve 61 and the inner sleeve 62. A receiving hole 64 and a discharge hole 611 extending in the axial direction CR are formed inside the outer sleeve 61. The end portion on the rear side of the receiving hole 64 communicates with the end portion on the front side of the discharge hole 611. The rear-side end portion 612 of the discharge hole 611 communicates with the front-side end portion of the discharge hole 230.

The inner sleeve 62 is formed substantially in a cylindrical tubular shape. The inner sleeve 62 has a function of receiving the spool 63, a function of supplying hydraulic oil to the vane rotor 20, and a function of providing a port for discharging hydraulic oil from the vane rotor 20. The inner sleeve 62 is received in a receiving hole 64 formed at the outer sleeve 61. The radial center of the inner sleeve 62 is formed with a through hole extending in the axial direction CR. The inner sleeve 62 has a retard port P1, an advance port P2, a cycle port P3, a retard supply port P4, and an advance supply port P5. These five ports P1-P5 are respectively formed as through holes that penetrate the peripheral wall of the inner sleeve 62 in the thickness direction (radial direction) of the peripheral wall of the inner sleeve 62. The retard port P1 may communicate with the retard oil passage 123 of the vane rotor 20 shown in fig. 2. Further, the advance port P2 shown in fig. 5 may communicate with the advance oil passage 124 of the vane rotor 20 shown in fig. 2. The circulation port P3 shown in fig. 5 is a port that returns a part of the hydraulic oil discharged from the vane rotor 20 to the vane rotor 20. The retard supply port P4 and the advance supply port P5 communicate with the hydraulic oil supply hole 615 of the outer sleeve 61.

The spool 63 is shaped into a bottomed tubular shape and is received in a through hole of the inner sleeve 62 so that the spool 63 can reciprocate in the axial direction CR. The length of the spool 63 measured in the axial direction CR is smaller than the length of the receiving hole 64 measured in the axial direction CR. With the above configuration, the spool 63 can move from the position shown in fig. 1 and 5 toward the rear side. As shown in fig. 5, a spring 65 is disposed on the rear side of the spool 63. The spring 65 is a coil spring. The front side end of the spring 65 contacts the rear side end of the spool 63, and the rear side end of the spring 65 contacts a step formed at the discharge hole 611 of the outer sleeve 61. The spring 65 urges the spool 63 toward the front side. The front side end portion of the spool 63 is in contact with the urging pin 71. When the urging pin 71 moves to the rear side, the spool 63 moves to the rear side against the urging force of the spring 65. The state shown in fig. 1 and 5 is a state in which the spool 63 is not pushed to the rear side by the push pin 71.

As shown in fig. 5, a retard side seal portion S1 and an advance side seal portion S2 are formed at the outer peripheral surface of the valve body 63. The retard side seal portion S1 and the advance side seal portion S2 are respectively formed in ridges that project outward in the radial direction and extend around the valve spool 63.

As shown in fig. 1 and 5, in a state where the spool 63 is not pushed to the rear side by the push pin 71, the retard supply port P4 and the retard port P1 communicate with each other. Further, in this state, the advance side seal S2 seals the connection between the advance supply port P5 and the advance port P2 so that hydraulic oil is not supplied from the advance supply port P5 to the advance port P2. Further, in this state, the advance port P2 communicates with the circulation port P3. As described above, in the state shown in fig. 1 and 5, the hydraulic oil is supplied from the hydraulic oil control valve 60 to the retard chamber 43 through the retard oil passage 123 of the vane rotor 20 shown in fig. 2, and the hydraulic oil is discharged from the advance chamber 44 through the advance oil passage 124 of the vane rotor 20. A part of the discharged hydraulic oil is supplied again to the retard port P1 through the circulation port P3 shown in fig. 5. Further, another part of the discharged hydraulic oil is discharged into the internal discharge hole 631 formed inside the spool 63 through the through hole 632 of the spool 63. A portion of the hydraulic oil discharged into the inner discharge hole 631 is discharged to the outside through the discharge hole 611 and the discharge hole 230. When the hydraulic oil is supplied to the retard chamber 43 shown in fig. 2 in the above-described manner, the vane rotor 20 rotates in the retard direction with respect to the housing 40. Thus, the relative rotational phase of the camshaft 200 with respect to the crankshaft is changed toward the retard side, i.e., retarded.

In contrast, in a state where the spool 63 is pushed to the rear side by the push pin 71 shown in fig. 5, the connection between the retard supply port P4 and the retard port P1 is sealed by the retard side seal portion S1, so that hydraulic oil is not supplied from the retard supply port P4 to the retard port P1. Further, in this state, the advance supply port P5 and the advance port P2 communicate. In this state, the retard supply port P4 communicates with the circulation port P3. In this state, hydraulic oil is supplied from the hydraulic control valve 60 to the advance chamber 44 through the advance oil passage 124 of the vane rotor 20 shown in fig. 2, and hydraulic oil is discharged from the retard chamber 43 through the retard oil passage 123. A part of the discharged hydraulic oil is resupplied to the advance port P2 through the circulation port P3 shown in fig. 5. In addition, another part of the discharged hydraulic oil is discharged to the internal discharge hole 631 through the through hole 632. A portion of the hydraulic oil discharged into the inner discharge hole 631 is discharged to the outside through the discharge hole 611 and the discharge hole 230. As described above, when the hydraulic oil is supplied to the advance chamber 44 shown in fig. 2, the vane rotor 20 rotates in the advance direction with respect to the housing 40. Therefore, the relative rotational phase of the camshaft 200 with respect to the crankshaft is changed toward the advance side, i.e., advanced. In the other state where the hydraulic oil is supplied to both the retard chamber 43 and the advance chamber 44, the rotation of the vane rotor 20 relative to the housing 40 is restricted. Thus, the current relative rotational phase of the camshaft 200 with respect to the camshaft 200/crankshaft is maintained.

A-2. Structure of locking device:

the locking device 80 shown in fig. 1 has a function of locking the vane rotor 20 in rotation relative to the housing 40. In this way, for example, at the time of starting the internal combustion engine, for example, in a state where the oil pressure is insufficient to maintain the rotational phase of the vane rotor 20, the collision of the housing 40 with the vane rotor 20 in the circumferential direction is restricted. In the present embodiment, the locking device 80 locks the rotation of the vane rotor 20 relative to the housing 40 at the most retarded phase of the valve timing. The locking device 80 includes a pin receiving portion 25, a stop pin 27, a spring 28, and a recess 90.

As described above, at the large vane 22 formed at the vane rotor 20, the pin receiving portion 25 is recessed in the axial direction CR so that the pin receiving portion 25 is opened to the front side. The pin receiving portion 25 is configured to oppose the recess 90, for example, at the most retarded phase of the valve timing. Specifically, the pin receiving portions 25 are placed at respective circumferential positions where the most retarded phase pin receiving portion 25 at the valve timing is opposed to the recess 90 of the housing 40. An oil discharge passage 26 is formed at a rear end face of a portion of the vane rotor 20 where the pin receiving portion 25 is formed. The oil discharge passage 26 communicates with the outside of the valve timing adjusting apparatus 100 through a discharge hole 292 formed at the rear cover 290.

The stopper pin 27 is shaped in a bottomed tube shape, is received in the pin receiving hole 25, and is configured to reciprocate in the axial direction CR along the pin receiving portion 25 and the recess 90, for example, at the most retarded phase of the valve timing. In the following description, the front-side end portion of the stopper pin 27 corresponding to the bottom will also be referred to as a distal end portion 271. The structure of the distal end portion 271 will be described later.

The spring 28 is a compression coil spring, and is arranged along the center axis of the stopper pin 27. The front side end of the spring 28 contacts the stop pin 27, and the rear side end of the spring 28 contacts the bottom of the pin receiving portion 25. The stopper pin 27 is pushed to the front side by the spring 28. In other words, the spring 28 urges the stopper pin 27 toward the recess 90. In a state where the vane rotor 20 is located at the most retarded phase while the oil pressure of the advance chamber 44 is insufficient, the distal end portion 271 of the stopper pin 27 is pushed into the recess 90 by the urging force of the spring 28.

As described above, the recess 90 shown in fig. 1, 3, and 4 is formed in the front wall portion 47 of the housing 40. The recess 90 is recessed in the axial direction CR at the rear side surface of the front wall portion 47.

As shown in fig. 6 and 7, a lower groove 91 and an upper groove 92 are formed at the recess 90. Fig. 6 is an enlarged view of a part of the concave portion 90 shown in fig. 4. For the sake of illustration, fig. 7 shows the retaining pin 27 and the ring element 49 as well as the recess 90. Fig. 7 shows a state where the vane rotor 20 is rotated in the advance direction with respect to the housing 40, for example, when the lock is released, and the distal end surface of the stopper pin 27 contacts the upper side groove 92. In fig. 7, the position of the stopper pin 27 in the locked state is indicated by a broken line. In the locked state, the distal end surface of the stopper pin 27 contacts the lower side groove 91.

The lower side groove 91 is formed in a cylindrical shape, and the stopper pin 27 is fitted into the lower side groove 91 in a locked state. As shown in fig. 7, the lower groove 91 is surrounded by a lower groove tubular portion (hereinafter referred to as a lower groove peripheral portion) 93 extending in the axial direction CR, a lower groove bottom portion 94 extending in the radial direction, and a tapered portion 95 formed in a tapered shape and connected between the lower groove tubular portion 93 and the lower groove bottom portion 94. In other words, the taper 95 is joined to the outer periphery of the lower groove bottom 94. In the present embodiment, as shown in fig. 1 and 7, a ring member 49 is fixed inside the lower groove tubular portion 93. The ring member 49 is made of iron and has a function of reinforcing the lower side groove 91. With the above structure, the stopper pin 27 is fitted into the lower side groove 91 through the ring member 49. In this embodiment, the annular member 49 is press-fitted into the lower recessed tubular portion 93.

As shown in fig. 3 and 4, an oil passage groove 96 is formed at the lower groove bottom 94, which communicates the corresponding advance chamber 44 shown in fig. 2 to the recess 90. The oil passage groove 96 extends substantially in the circumferential direction. As shown in fig. 1, in the fitting state, i.e., the locked state, in which the stopper pin 27 is fitted into the lower groove 91, when hydraulic oil is supplied into the oil passage groove 96 when the pressure of the advance chamber 44 is increased by the oil pressure control operation using the hydraulic oil control valve 60, the urging force that urges the stopper pin 27 to the rear side is greater than the urging force of the spring 28. When the distal end portion 271 of the stopper pin 27 shown in fig. 7 is removed from the ring member 49 and the lower groove 91 by the pressure of the hydraulic oil, the entire range of the stopper pin 27 measured in the axial direction CR is received in the pin receiving portion 25 of the vane rotor 20 shown in fig. 1. When the lock is released in this manner, the vane rotor 20 can be rotated relative to the housing 40. The hydraulic oil introduced from the oil passage groove 96 into the lower side groove 91 at the time of releasing the lock is returned to the oil pan 500 through the oil discharge passage 26 and the drain hole 292.

As shown in fig. 3, 4 and 6, the upper side groove 92 is formed continuously with the lower side groove 91 in the circumferential direction. More specifically, the upper groove 92 is formed on the advance side of the lower groove 91, and is continuous with the lower groove 91. As shown in fig. 7, the groove depth D1 of the upper groove 92 measured in the axial direction CR is smaller than the groove depth D2 of the lower groove 91 measured in the axial direction CR.

In the case where the peripheral portion of the housing 40 surrounding the lower groove 91 is deformed in the thrust direction in response to the stress generated at the lower groove 91, the upper groove 92 has a function of restricting the interference between the housing 40 and the vane rotor 20. The stress generated at the lower groove 91 may be, for example, a stress generated when torque is applied to the valve timing adjusting apparatus 100 in an assembled state of the stopper pin 27, that is, an assembled state in which the stopper pin 27 is assembled into the lower groove 91. The torque may be, for example, a torque generated when the valve timing adjustment apparatus 100 is connected to the end of the camshaft 200, or a torque generated at the camshaft 200 when the internal combustion engine is operated. In the present embodiment, the stopper pin 27 is fitted into the lower groove 91 in the most retarded phase, so that the valve timing adjusting apparatus 100 is susceptible to the influence of the torque applied in the advance direction. As in the present embodiment, in the structure in which the ring member 49 is press-fitted into the lower groove tubular portion 93 of the lower groove 91, stress is also generated at the lower groove 91 when the ring member 49 is press-fitted into the lower groove tubular portion 93. The upper side groove 92 is formed as a relief portion that is used when the housing 40 is raised in the thrust direction by such stress.

As shown in fig. 6, the upper side groove 92 is formed in a convex bow shape (in the form of a convex arc) protruding in a direction directed from the lower side groove 91 to the upper side groove 92 as viewed in the axial direction CR. In the present embodiment, the "direction directed from the lower groove 91 to the upper groove 92" approaches or coincides with the advance direction. With this structure, in the case where stress is generated at the lower groove 91, the stress can be dispersed, so that local deformation of the housing 40 in the thrust direction can be restricted. The upper groove 92 has a radially extending upper groove bottom 97. In the present embodiment, the radius of the circular arc of the upper groove bottom 97 (hereinafter referred to as circular arc radius) r1 is equal to the radius r2 of the lower groove bottom 94. As shown in fig. 7, when the lock is released, the distal end surface of the stopper pin 27 removed from the lower groove 91 comes into contact with the upper groove bottom 97.

As shown in fig. 6 and 7, a portion of the outer periphery of the upper side groove 92 which is spaced apart from the lower side groove 91 and thus is not engaged with the lower side groove 91 is defined as an upper side groove outer peripheral portion 98. Therefore, the upper groove outer peripheral portion 98 is formed in an arcuate shape as viewed in the axial direction CR.

As shown in fig. 8, the upper groove peripheral portion 98 is formed to extend in a direction intersecting each of the axial direction CR and the radial direction, that is, the surface of the upper groove peripheral portion 98 extends in a direction intersecting each of the axial direction CR and the radial direction. A first angle θ 1 defined between the upper groove peripheral portion 98 and the upper groove bottom portion 97 is an obtuse angle. In the present embodiment, the first angle θ 1 is 135 degrees. However, the first angle θ 1 is not necessarily limited to 135 degrees, and may be an angle greater than 90 degrees but less than 180 degrees. In the present embodiment, the first angle θ 1 is equal to the second angle θ 2, and the second angle θ 2 is an angle defined between the lower groove bottom 94 and the taper 95. Fig. 8 is an enlarged view schematically showing a cross section similar to that shown in fig. 7.

As described above, the concave portion 90 of the present embodiment is formed such that the circular arc radius r1 of the upper side groove bottom 97 is equal to the radius r2 of the lower side groove bottom 94, and the first angle θ 1 and the second angle θ 2 are equal to each other. Thus, as schematically shown in fig. 9, the upper and

lower grooves

92, 91 may be formed by a cutting process, wherein a tool (e.g., a milling cutter having one or more cutting inserts) D, also referred to as a cutting tool, is commonly used to form the upper and

lower grooves

92, 91. Fig. 9 shows a state where the cutter D cuts the lower groove 91, and another state where the cutter D cuts the upper groove 92 is indicated by a dotted line. Further, fig. 9 shows a diameter Φ 1 of an imaginary circle formed by extending the entire arc of the upper groove bottom 97 having the radius r1 circumferentially around the center of the arc of the upper groove bottom 97. FIG. 9 also shows the diameter φ 2 of the underside groove bottom 94, which is equal to the diameter φ 1. As described above, by machining the lower side groove 91 and the upper side groove 92 using the tool D in common, the complexity of the cutting process of the recess 90 can be limited, and thus the increase in the cost required for machining the groove 90 can be limited.

As shown in fig. 7, in the cross section of the stopper pin 27, the distal end portion 271 of the stopper pin 27 is formed in a rounded shape (R-shape) such that the distal end portion 271 is tapered toward the front side, i.e., the diameter is gradually reduced toward the front side. In other words, the distal end portion 271 of the stopper pin 27 is tapered toward the recess 90, i.e., its diameter is gradually reduced toward the recess 90. The remaining portion of the stopper pin 27 other than the distal end portion 271 is formed in a straight shape extending straight in the axial direction CR. In the present embodiment, the groove depth D1 of the upper side groove 92 measured in the axial direction CR is smaller than the length D3 of the distal end portion 271 of the stopper pin 27 measured in the axial direction CR. With this structure, the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27 are opposed to each other at the curved surfaces of the surface of the upper groove peripheral portion 98 (which extends in the direction intersecting the axial direction CR) and the distal end portion 271 in a state where the distal end surface of the stopper pin 27 is in contact with the upper groove bottom portion 97 of the upper groove 92. Therefore, the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27 do not oppose each other at a surface (or plane) extending in the axial direction CR. In other words, the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27 do not make line contact or surface contact with each other along a surface or (plane) such as a cylindrical surface (or a cylindrical plane) extending in the axial direction CR. Therefore, when the lock is released, the stopper pin 27 can be restricted from being caught by the upper groove peripheral portion 98 of the upper groove 92. Therefore, at the time of releasing the lock, the stopper pin 27 can be smoothly advanced in the advance direction so as not to interfere with the release of the lock.

In the valve timing adjustment device 100 of the present embodiment described above, the recess 90 has: a lower groove 91 configured to receive the retaining pin 27; an upper groove 92 that is engaged with the lower groove 91 in the circumferential direction, and the groove depth of the upper groove 92 measured in the axial direction CR is smaller than the groove depth of the lower groove 91 measured in the axial direction CR. Thus, when the housing 40 is deformed in response to the stress generated at the lower groove 91, the interference between the housing 40 and the vane rotor 20 can be restricted. Therefore, deterioration of the degree of sliding between the housing 40 and the vane rotor 20 can be restricted. Further, in a state where the distal end surface of the stopper pin 27 is in contact with the upper side recessed groove 92, the upper side recessed groove peripheral portion 98 (which is a portion of the outer periphery of the upper side recessed groove 92 that is not engaged with the lower side recessed groove 91) is not opposed to the distal end portion 271 of the stopper pin 27 at the surface extending in the axial direction CR. Therefore, when the lock is released, the stopper pin 27 can be restricted from being caught by the upper groove peripheral portion 98. Therefore, while interference between the housing 40 and the rotor blade 20 is restricted, release of the lock is not interfered.

Further, the distal end portion 271 of the stopper pin 27 is tapered toward the recess 90, that is, its diameter is gradually reduced toward the recess 90, and the groove depth D1 of the upper side groove 92 measured in the axial direction CR is smaller than the length D3 of the distal end portion 271 measured in the axial direction CR. Therefore, a structure can be easily achieved in which the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27 do not oppose each other at the surface extending in the axial direction CR. In addition, since the first angle θ 1 defined between the upper groove peripheral portion 98 and the upper groove bottom portion 97 is an obtuse angle, a structure can be easily achieved in which the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27 do not oppose each other at a surface extending in the axial direction CR.

Further, the first angle θ 1 is equal to a second angle θ 2 defined between the lower groove bottom 94 and the taper 95. Therefore, workability (formability) of the upper and

lower grooves

92 and 92 is improved, and the upper and

lower grooves

92 and 91 may be formed by a cutting process in which the cutter D is used in common to form the upper and

lower grooves

92 and 91. Therefore, the complexity of the machining step of the concave portion 90 can be limited, and thus the increase in required cost required for machining the concave portion 90 can be limited.

Further, since the upper groove 92 is shaped like a convex bow protruding in a direction from the lower groove 91 toward the upper groove 92 as viewed in the axial direction CR, in the case where stress is generated at the lower groove 91, the stress can be dispersed. Thereby, local deformation of the housing 40 in the thrust direction can be restricted. Therefore, the interference between the housing 40 and the vane rotor 20 can be effectively restricted.

Further, the arc radius r1 of the upper groove bottom 97 is equal to the radius r2 of the lower groove bottom 94. Therefore, the workability of the upper side groove 92 and the lower side groove 91 can be improved. Further, the circular arc radius r1 and the radius r2 are equal to each other, and the first angle θ 1 and the second angle θ 2 are equal to each other. Therefore, the upper side groove 92 and the lower side groove 91 may be formed by a cutting process in which the cutter D is used in common to form the upper side groove 92 and the lower side groove 91. Therefore, the complexity of the machining step of the concave portion 90 can be limited, and thus the increase in required cost required for machining the concave portion 90 can be limited.

The annular member 49 is fixed to the radially inner side of the lower side groove tubular portion 93, thereby reinforcing the lower side groove 91, so that the wear of the lower side groove 91 can be restricted. The annular member 49 is fixed in place by press fitting so that assembly of the annular member 49 to the lower recess 91 can be simplified. Further, in the valve timing adjusting apparatus 100 of the present embodiment, the interference between the housing 40 and the vane rotor 20 can be restricted, and therefore, the present embodiment is applicable to a structure in which the annular member 49 is press-fitted into the lower-side groove tubular portion 93.

B. Other examples are as follows:

b-1. first other embodiment:

in the above embodiment, the distal end portion 271 of the stopper pin 27 is formed in a circular shape (R-shape). However, the shape of the distal end portion 271 of the stopper pin 27 is not necessarily limited to a circle (R-shape). For example, the distal end 271 of the retaining pin 27 may be tapered toward the recess 90, i.e., its diameter may gradually decrease toward the recess 90. Further, in the case of a structure in which the first angle θ 1 is an obtuse angle, the distal end portion 271 of the stopper pin 27 may be formed in a straight shape extending straight in the axial direction CR. Even with this structure, the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27 do not oppose each other at the surface extending in the axial direction CR in the state where the distal end surface of the stopper pin 27 contacts the upper groove bottom portion 97 of the upper groove 92. Therefore, advantages similar to those of the above-described embodiments can be achieved.

B-2. second other embodiment:

the structure of the upper side groove 92 of the above embodiment is merely an example, and may be modified in various other forms. For example, in the above-described embodiment, the groove depth D1 of the upper groove 92 measured in the axial direction CR is smaller than the length D3 of the distal end portion 271 measured in the axial direction CR. Alternatively, the groove depth D1 of the upper side groove 92 may be equal to the length D3 of the distal end portion 271. Further, for example, in a structure in which the first angle θ 1 is an obtuse angle, the groove depth D1 of the upper groove 92 measured in the axial direction CR may be greater than the length D3 of the distal end portion 271 measured in the axial direction CR. Further, for example, in the above-described embodiment, the upper groove peripheral portion 98 is formed to extend in the direction intersecting the axial direction CR and the radial direction. Alternatively, the upper groove peripheral portion 98 may be shaped in a curved surface form. Further, for example, in the above-described embodiment, the first angle θ 1 defined between the upper groove peripheral portion 98 and the upper groove bottom portion 97 is an obtuse angle. Alternatively, in a structure in which the distal end portion 271 is tapered toward the recess 90, that is, the diameter is gradually reduced toward the recess 90, and the groove depth D1 of the upper side groove 92 measured in the axial direction CR is smaller than the length D3 of the distal end portion 271 measured in the axial direction CR, the first angle θ 1 may be a right angle. Further, for example, in the above-described embodiment, the upper groove bottom 97 extends in the radial direction. Alternatively, the upper groove bottom 97 may be tapered such that the groove depth D1 of the upper groove 92 measured in the axial direction CR gradually increases from the upper groove peripheral portion 98 toward the lower groove 91. Even with this structure, similar advantages to those of the above-described embodiment can be achieved.

B-3. third other embodiment:

in the above-described embodiment, the upper groove outer peripheral portion 98 extending in the direction intersecting the axial direction CR is opposed to the distal end portion 271 of the stopper pin 27, which is formed into a curved surface shape, in a state where the distal end surface of the stopper pin 27 is in contact with the upper groove bottom portion 97 of the upper groove 92. However, the present invention is not necessarily limited to this structure. For example, the upper groove outer peripheral portion 98 and the distal end portion 271 may be respectively configured in a curved surface shape. Further, the upper groove peripheral portion 98 and the distal end portion 271 may be opposed to each other such that a surface of the upper groove peripheral portion 98 extending in a direction intersecting the axial direction CR and a surface of the distal end portion 271 extending in a direction intersecting the axial direction CR are opposed to each other. Specifically, in a state where the distal end surface of the stopper pin 27 is in contact with the upper groove bottom 97 of the upper groove 92, at least one of the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27 has a surface extending in a direction intersecting the axial direction CR, and the surface is opposed to the other of the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27. Further alternatively, at least one of the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27 may have a curved surface that is opposed to the other of the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27. Even with this structure, the upper groove peripheral portion 98 and the distal end portion 271 of the stopper pin 27 do not oppose at the surface extending in the axial direction CR. Therefore, advantages similar to those of the above-described embodiments can be achieved.

B-4. fourth other embodiment:

although the first angle θ 1 and the second angle θ 2 are equal to each other in the above-described embodiment, the first angle θ 1 and the second angle θ 2 may be different from each other. Further, although in the above-described embodiment, the circular arc radius r1 and the radius r2 are equal to each other, the circular arc radius r1 and the radius r2 may be different from each other. In addition, in the above-described embodiment, the upper side groove 92 is formed in a convex arcuate shape that protrudes in a direction directed from the lower side groove 91 to the upper side groove 92 as viewed from the axial direction CR. However, the shape of the upper side groove 92 is not necessarily limited to the arcuate shape, but may be any other suitable form. Even with this structure, similar advantages to those of the above-described embodiment can be achieved.

B-5. fifth other embodiment:

for example, the structure of the valve timing adjusting apparatus 100 of the above-described embodiment is merely an example, and may be modified in various other forms. For example, the driving-side rolling body 300 may include a sprocket instead of the pulley 10, and the driving force of the crankshaft may be transmitted to the driving-side rolling body 300 through a timing chain wound around the sprocket. Further, for example, the recess 90 may be formed at the sprocket or the flange 12 of the pulley 10 instead of the housing 40. Specifically, the recess 90 may be configured to be opposed to the pin receiving portion 25 at the driving-side rolling body 300. Further, for example, the ring member 49 may be omitted. Further, for example, the locking device 80 need not be configured to lock the rotation of the vane rotor 20 relative to the housing 40 at the most retarded phase. For example, the locking device 80 may be configured to lock the rotation of the vane rotor 20 relative to the housing 40 at the most advanced phase. Further, for example, the hydraulic oil control valve 60 does not have to be driven by the solenoid 70. For example, the hydraulic oil control valve 60 may be driven by any other type of actuator, such as an electric motor or a pneumatic cylinder. Also, the hydraulic oil control valve 60 may be placed outside the valve timing adjusting apparatus 100. Further, the valve timing adjusting apparatus 100 may be configured to adjust the valve timing of the exhaust valve instead of adjusting the valve timing of the intake valve, which is opened and closed by the camshaft 200. Even with this structure, similar advantages to those of the above-described embodiment can be achieved.

The present invention is not necessarily limited to the above-described embodiments, and may be implemented in various other forms without departing from the scope of the invention. For example, technical features corresponding to those described in the summary of the invention in each embodiment may be appropriately replaced or combined to solve some or all of the above disadvantages or to provide one or more or all of the above advantages. If any one or more technical features are not described as essential in the present specification, such technical features may be appropriately deleted.

Claims

1. A valve timing adjusting apparatus to be fixed to an end portion of a driven-side shaft (200) configured to receive a driving force from a driving-side shaft to open and close a valve, while the valve timing adjusting apparatus is configured to adjust a relative rotational phase of the driven-side shaft (200) with respect to the driving-side shaft to adjust a valve timing of the valve, the valve timing adjusting apparatus comprising:

a drive-side rotating body (300) having an internal space and configured to rotate in synchronization with the drive-side shaft;

a vane rotor (20) received in the internal space of the driving-side rolling body (300) and connected to the driven-side shaft (200), wherein the vane rotor (20) includes a vane (22), the vane (22) partitions the internal space into a plurality of hydraulic chambers, and the vane rotor (20) is configured to rotate relative to the driving-side rolling body (300) when the vane (22) receives a pressure of hydraulic oil introduced into one of the plurality of hydraulic chambers; and

a locking device (80) configured to lock rotation of the vane rotor (20) relative to the drive-side rolling body (300), wherein:

the locking device (80) comprises:

a pin receiving portion (25) that is formed at the vane rotor (20) and extends in an axial direction (CR) parallel to a rotational axis (CX) of the drive-side rolling body (300);

a recess (90) formed at the driving-side rolling body (300) and configured to be opposite to the pin receiving portion (25);

a stopper pin (27) received in the pin receiving portion (25) and configured to reciprocate in the axial direction (CR) along the pin receiving portion (25) and the recess (90); and

a spring (28) configured to urge the stopper pin (27) toward the recess (90);

the groove (90) has:

a lower groove (91) configured to receive the retaining pin (27); and

an upper groove (92) joined to the lower groove (91) in the circumferential direction and having a groove depth measured in the axial direction (CR) that is smaller than the groove depth of the lower groove (91) measured in the axial direction (CR); and

an upper groove peripheral portion (98) is not opposed to a distal end portion (271) of the stopper pin (27) at a surface extending in the axial direction (CR) in a state where a distal end surface of the stopper pin (27) is in contact with the upper groove (92), the upper groove peripheral portion (98) being a portion of an outer periphery of the upper groove (92) which is spaced apart from the lower groove (91) and is thereby not engaged to the lower groove (91).

2. The valve timing adjustment apparatus according to claim 1, wherein:

the distal end (271) of the retaining pin (27) has a diameter that gradually decreases towards the recess (90); and

the upper groove (92) has a groove depth (D1) measured in the axial direction (CR) that is smaller than a length (D3) of the distal end portion (271) of the retaining pin (27) measured in the axial direction (CR).

3. The valve timing adjustment apparatus according to claim 1, wherein:

the upper groove (92) having an upper groove bottom (97) extending in a radial direction perpendicular to the axial direction (CR); and

a first angle (θ 1) defined between the upper groove peripheral portion (98) and the upper groove bottom portion (97) is an obtuse angle.

4. The valve timing adjustment apparatus according to claim 3, wherein:

the lower groove (91) having a lower groove bottom (94) extending in the radial direction and a taper (95) that tapers and is joined to an outer circumference of the lower groove bottom (94); and

the first angle (θ 1) is equal to a second angle (θ 2) defined between the lower groove bottom (94) and the taper (95).

5. The valve timing adjustment apparatus according to any one of claims 1 to 4, wherein:

the upper groove (92) is shaped like a convex bow protruding in a direction from the lower groove toward the upper groove, as viewed in the axial direction (CR).

6. The valve timing adjustment apparatus according to claim 4, wherein:

the upper groove (92) is shaped, as viewed in the axial direction (CR), as a convex bow projecting in a direction from the lower groove toward the upper groove,

the lower groove (91) is formed in a cylindrical shape; and

the arc radius (r1) of the upper groove bottom (97) is equal to the radius (r2) of the lower groove bottom (94).