Valve timing adjustment device

Abstract

The present invention provides a valve timing change device that suppresses or prevents leakage of hydraulic fluid around the sealing member, thereby preventing overshoot and hunting phenomena during phase angle changes, and enabling rapid control of valve timing. [Solution] The system comprises a housing rotor 20 rotatable around the axis S of the camshaft 1, a vane rotor 10 rotatable relative to the housing rotor within a predetermined angular range and rotating integrally with the camshaft, and having a seal groove 18 formed therein, a seal member 60 positioned in the seal groove and in contact with the inner circumferential surface 21g of the housing rotor, and a biasing spring 70 positioned in the seal groove and biasing the seal member toward the inner circumferential surface. The seal groove 18 extends in the axial direction and has a concave shape with both sides 18a and a bottom surface 18b, and includes stepped surfaces 18a3 as bent surfaces on both sides 18a, and the seal member 60 has a cross-sectional shape that follows both sides including the bent surfaces.

Description

Technical Field

[0001] The present invention relates to a valve timing changing device that changes the opening and closing timing (valve timing) of an intake valve or an exhaust valve of an internal combustion engine according to the operating conditions.

Background Art

[0002] As a conventional valve timing changing device, there is known a valve timing changing device including a housing rotor that rotates synchronously with a crankshaft on the axis of a camshaft, a vane rotor that rotates integrally with the camshaft and can relatively rotate within a predetermined angular range with respect to the housing rotor, a seal groove formed on the tip surface of the vane rotor, a seal member disposed in the seal groove and contacting the inner peripheral surface of the housing rotor to block an advance angle chamber and a retard angle chamber, a leaf spring disposed in the seal groove to urge the seal member toward the inner peripheral surface of the housing rotor, etc. (see, for example, Patent Document 1).

[0003] In this valve timing changing device, the seal member has a rectangular cross section, and the seal groove is formed as a concave groove having both side surfaces that define a groove width larger than the cross section of the seal member. Then, by actively introducing hydraulic oil into the seal groove, the hydraulic pressure of the hydraulic oil is used to bring the seal member into contact with one side surface of the seal groove to ensure sealing performance. However, there is a risk that during the period when the seal member instantaneously moves away from one side surface of the seal groove and contacts the other side surface due to the influence of the hydraulic pressure of the hydraulic oil, the advance angle chamber and the retard angle chamber communicate with each other, the leakage amount of the hydraulic oil increases, the vane rotor greatly changes with respect to the target phase, repeats overshoot, and causes a hunting phenomenon and becomes uncontrollable.

[0004] Furthermore, other valve timing adjustment devices are known that, as described above, include a housing rotor, a vane rotor, a seal groove formed on the tip surface of the vane rotor, and a seal member positioned in the seal groove and in contact with the inner circumferential surface of the housing rotor to separate the advance and retard chambers (see, for example, Patent Document 2).

[0005] In this valve timing adjustment device, the seal member has a trapezoidal cross-section, and the seal groove is formed as a trapezoidal concave groove with two sides that define a groove width larger than the cross-section of the seal member. By actively introducing hydraulic fluid into the seal groove, the hydraulic pressure of the hydraulic fluid is used to bring the seal member into contact with one side of the seal groove, thereby ensuring a seal. However, as mentioned above, due to the influence of hydraulic pressure from the hydraulic fluid, the advance and retard chambers of the sealing member momentarily communicate with each other as it moves away from one side of the seal groove and into contact with the other side, which can increase the amount of hydraulic fluid leakage. This can cause the vane rotor to change significantly relative to the target phase, leading to repeated overshoots, a hunting phenomenon, and ultimately, loss of control. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-4581 [Patent Document 2] Patent No. 6432413 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention has been made in view of the problems of the prior art described above, and aims to provide a valve timing changing device that can suppress or prevent leakage of hydraulic fluid around a sealing member, thereby preventing overshoot and hunting phenomena when the phase angle is changed, and enabling quick control of valve timing. [Means for solving the problem]

[0008] The valve timing changing device of the present invention is a valve timing changing device for changing the opening and closing timing of an intake valve or exhaust valve driven by a camshaft, and comprises a housing rotor rotatable around the axis of the camshaft, a vane rotor rotatable relative to the housing rotor within a predetermined angular range and rotating integrally with the camshaft and having a seal groove formed therein, a seal member disposed in the seal groove and in contact with the inner circumferential surface of the housing rotor, and a biasing spring disposed in the seal groove and biasing the seal member toward the inner circumferential surface, wherein the seal groove extends in the axial direction of the camshaft and has a concave shape with both sides and a bottom surface and includes bent surfaces on both sides, and the seal member has a cross-sectional shape along both sides including the bent surfaces.

[0009] In the valve timing changing device described above, the seal groove may include a wide side surface defining a first groove width on the opening side, a narrow side surface defining a second groove width narrower than the first groove width near the bottom surface, and a stepped surface connecting the wide side surface and the narrow side surface to define a bent surface, and the seal member may include a wide opposing surface facing the wide side surface, a narrow opposing surface facing the narrow side surface, and a stepped opposing surface facing the stepped surface.

[0010] In the valve timing changing device described above, a configuration may be adopted in which the gap between the wide side surface and the wide opposing surface is smaller than the gap between the narrow side surface and the narrow opposing surface.

[0011] In the valve timing changing device described above, the sealing member may be configured to include a wide portion defining a wide opposing surface, a pair of narrow portions extending from the wide portion toward the bottom surface at both ends in the axial direction and defining a narrow opposing surface, and a weight-reducing portion on the side facing the bottom surface in the region sandwiched between the pair of narrow portions.

[0012] In the valve timing changing device described above, the sealing member may be configured to include guide grooves inside a pair of narrow sections that guide both ends of the biasing spring.

[0013] In the valve timing changing device described above, a configuration in which the gap between the wide side surface and the wide opposing surface is 0.02 to 0.17 mm may be adopted.

[0014] In the valve timing changing device described above, the seal groove may include recessed portions that extend axially on both sides to define a bent surface and recessed in a direction perpendicular to the axis, and the seal member may have a configuration that includes opposing surfaces facing both sides and convex portions inserted into the recessed portions.

[0015] In the valve timing changing device described above, the recessed portion may have a rectangular concave cross-section perpendicular to the axis, and the convex portion may have a rectangular convex cross-section perpendicular to the axis.

[0016] In the valve timing changing device described above, a configuration may be adopted in which the gap between both sides and the opposing surface is smaller than the gap between the concave portion and the convex portion.

[0017] In the valve timing changing device described above, the recessed portion may include a pair of extending surfaces that extend vertically from both sides and a rear end surface that is continuous perpendicularly to the pair of extending surfaces, and the convex portion may include a pair of protruding opposing surfaces that face the pair of extending surfaces and a protruding end surface that is continuous perpendicularly to the pair of protruding opposing surfaces, wherein the gap between the extending surfaces and the protruding opposing surfaces is smaller than the gap between the rear end surface and the protruding end surface.

[0018] In the valve timing changing device described above, the sealing member may be configured to include an elongated portion defining a part of the opposing surface, protruding portions on both sides of the elongated portion that protrude from the opposing surface, a pair of protruding portions on both ends in the axial direction that protrude toward the bottom surface than the protruding portions and define a part of the opposing surface, and a weight-reducing portion on the side facing the bottom surface in the region sandwiched between the pair of protruding portions.

[0019] In the valve timing changing device described above, the sealing member may be configured to include guide grooves inside a pair of protrusions that guide both ends of the biasing spring.

[0020] In the valve timing changing device, the clearance between both side surfaces and the opposing surface may be 0.02 to 0.17 mm.

[0021] In the valve timing changing device, the biasing spring may be a leaf spring arranged to be convexly curved toward the bottom surface of the seal groove.

[0022] In the valve timing changing device, the biasing spring may include a curved portion formed such that the central region is convexly curved on the side opposite to the bottom surface in the axial direction, and is arranged to contact the bottom surface at two locations on both sides sandwiching the curved portion.

[0023] In the valve timing changing device, the seal member may include stepped portions extending in the axial direction on both sides around the axis sandwiching the contact surface contacting the inner peripheral surface of the housing rotor.

[0024] In the valve timing changing device, the stepped portion may include a vertical surface oriented perpendicular to the inner peripheral surface and a stepped-down surface continuously perpendicular to the vertical surface.

[0025] In the valve timing changing device, the seal member may be formed of a resin material.

Advantages of the Invention

[0026] According to the valve timing changing device having the above configuration, leakage of the working oil around the seal member can be suppressed or prevented, overshoot and hunting phenomena during phase angle change can be prevented, and the valve timing can be controlled quickly.

Brief Description of the Drawings

[0027] [Figure 1] It is an external perspective view showing the valve timing changing device of the present invention. [Figure 2]This is an exploded perspective view of the valve timing changing device according to the first embodiment, viewed from the front at an oblique angle after disassembly. [Figure 3] This is an exploded perspective view of the valve timing changing device according to the first embodiment, taken from a rearward oblique angle after disassembly. [Figure 4] This is a cross-sectional view of the valve timing changing device according to the first embodiment, taken from a plane passing through the axis of the camshaft. [Figure 5] This is a perspective cross-sectional view of the valve timing changing device according to the first embodiment, showing the region where the seal groove, seal member, and biasing spring are arranged, cut by a plane passing through the axis of the camshaft. [Figure 6] This is a partial cross-sectional view of the valve timing changing device according to the first embodiment, in which the area where the seal groove, seal member, and biasing spring are arranged is cut by a plane passing through the axis of the camshaft. [Figure 7] This is an enlarged perspective view showing the area of ​​the seal groove of the vane rotor included in the valve timing changing device according to the first embodiment. [Figure 8] This is a perspective exploded view showing the seal member and biasing spring included in the valve timing changing device according to the first embodiment, disassembled. [Figure 9] This is an end view showing a seal groove, a seal member, and a biasing spring in a valve timing changing device according to the first embodiment, in a plane perpendicular to the axis of the camshaft. [Figure 10] This is a partial cross-sectional view of a valve timing changing device according to the first embodiment, showing the seal groove, the seal member, and the biasing spring in a cross section perpendicular to the axis of the camshaft and in the region of the guide groove of the seal member. [Figure 11] This is a partial cross-sectional view of a valve timing changing device according to the first embodiment, showing a seal groove, a seal member, and a biasing spring in a cross section perpendicular to the axis of the camshaft and in the central region of the seal member. [Figure 12] This is a cross-sectional view showing the state in which the vane rotor is at the retarded angle position in the valve timing changing device according to the first embodiment. [Figure 13]This is a cross-sectional view showing the state in which the vane rotor is at the most advanced angle position in the valve timing changing device according to the first embodiment. [Figure 14] This graph shows the results of a simulation comparing the amount of phase angle variation in the valve timing changing device according to the first embodiment with that of a conventional structure. [Figure 15] This is an exploded perspective view of the valve timing changing device according to the second embodiment, taken from a front oblique angle after disassembly. [Figure 16] This is a perspective view showing a vane rotor, sealing member, etc., included in a valve timing changing device according to the second embodiment. [Figure 17] This is an enlarged perspective view showing the area of ​​the seal groove of the vane rotor included in the valve timing changing device according to the second embodiment. [Figure 18] This is a perspective exploded view showing the seal member and biasing spring included in the valve timing changing device according to the second embodiment, disassembled. [Figure 19] This is an end view showing a seal groove, a seal member, and a biasing spring in a valve timing changing device according to the second embodiment, in a plane perpendicular to the axis of the camshaft. [Figure 20] In a valve timing changing device according to the second embodiment, this is a partial cross-sectional view showing the seal groove, the seal member, and the biasing spring in a cross section perpendicular to the axis of the camshaft and in the region of the guide groove of the seal member. [Figure 21] In a valve timing changing device according to the second embodiment, this is a partial cross-sectional view showing the seal groove, the seal member, and the biasing spring in a cross section perpendicular to the axis of the camshaft and in the central region of the seal member. [Modes for carrying out the invention]

[0028] Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in Figure 1, the valve timing changing device M1 according to the first embodiment of the present invention is mounted on the camshaft 1 of an internal combustion engine, and as shown in Figures 2 to 6, it comprises a vane rotor 10, a housing rotor 20, an annular spacer 30, a locking mechanism 40 for locking the vane rotor 10 against the housing rotor 20, a rotation biasing spring 50, a sealing member 60, and a biasing spring 70.

[0029] Here, the housing rotor 20 is supported so as to be rotatable around the axis S of the camshaft 1, and the vane rotor 10 and annular spacer 30 are rotatable relative to the housing rotor 20 within a predetermined angular range and rotate integrally with the camshaft 1, having a seal groove 18 in which a seal member 60 and a biasing spring 70 are arranged.

[0030] The camshaft 1 is rotatably supported around axis S by a bearing formed in the cylinder head of the internal combustion engine, and drives the intake valve or exhaust valve to open and close by cam action. As shown in Figure 1, the camshaft 1 also includes a circular shaft portion 1a that rotatably supports the housing rotor 20, passages 1b and 1c for supplying and discharging hydraulic fluid, a female screw hole 1d into which a bolt B is screwed, and a fitting hole 1e into which a positioning pin P1 is fitted.

[0031] The valve timing changing device M1 has a vane rotor 10 and annular spacer 30 fixed to the camshaft 1 using bolts B. The housing rotor 20 is linked to the rotation of the crankshaft via a linking member such as a chain or gear, and the rotational driving force of the crankshaft is transmitted to the camshaft 1 via the vane rotor 10. It is also connected to a hydraulic control system 2 that controls the flow of hydraulic fluid, thereby performing the function of changing the valve timing in an internal combustion engine. As shown in Figure 1, the hydraulic control system 2 consists of a hydraulic control valve 2a that controls the flow of hydraulic fluid discharged from the pump, a passage 2b that connects the hydraulic control valve 2a and passage 1b, a passage 2c that connects the hydraulic control valve 2a and passage 1c, and control means (not shown) that controls the driving of the hydraulic control valve 2a. Here, in the valve timing changing device M1, the side into which bolt B is inserted is referred to as the "front side," and the side to which the camshaft 1 is connected is referred to as the "rear side."

[0032] The vane rotor 10 is formed as a molded or forged product using an aluminum alloy or other metal material, and as shown in Figures 2 to 7, it has a front surface 10a and a rear surface 10b, four vane sections 11, a cylindrical hub section 12, a through hole 13, a recess 13a, a fitting hole 13b for fitting a positioning pin P2, a mounting hole 14 for attaching a locking mechanism 40, passages 15, 16, a fitting recess 17 for fitting a camshaft 1, four seal grooves 18 formed at the tips of the four vane sections 11, and a positioning hole 19 for fitting a positioning pin P1 of the camshaft 1.

[0033] The four vane sections 11 are arranged at approximately equal intervals relative to the hub section 12. A mounting hole 14 for attaching the locking mechanism 40 is formed in one of the vane sections 11. The through hole 13 extends from the front surface 10a to the rear surface 10b, centered on the axis S, in order to allow the threaded portion and the lower part of the bolt B to pass through without contact, thereby defining a passage for hydraulic fluid around the lower part of the bolt. The recess 13a is formed in a cylindrical shape that is recessed in the direction of the axis S from the front surface 10a, with the axis S as the center, so that the annular spacer 30 can be joined by press-fitting. The fitting hole 13b is formed to extend in the axial direction S on the bottom surface of the recess 13a in order to fit the positioning pin P2.

[0034] As shown in Figures 3 and 4, the mounting hole 14 opens on the rear surface 10b and is formed to accommodate the cylindrical holder 41 of the locking mechanism 40. The mounting hole 14 is also formed to connect to pressure adjustment passages 14a and 14b. Passage 14a connects to a long groove 14a1 formed on the front surface 10a, which communicates with the outside through the opening 21d. Passage 14b opens on the side of one vane portion 11 and connects to the retarding chamber RC, supplying hydraulic fluid within the retarding chamber RC that acts in a direction to embed the lock pin 42.

[0035] As shown in Figures 2, 3, and 12, passage 15 is formed by two groove-shaped passages 15a formed on the bottom surface of the fitting recess 17 and communicating with passage 1c of the camshaft 1, and four passages 15b opening on the outer circumferential surface of the hub portion 12. Passage 15 supplies hydraulic fluid to the retardation chamber RC and discharges hydraulic fluid from the retardation chamber RC via passages defined around the lower part of the neck of the bolt B within the through hole 13. As shown in Figures 2, 3, and 13, passage 16 is formed by four passages 16a that open to the bottom surface of the fitting recess 17 and extend in the direction of the axis S, communicating with passage 1b of the camshaft 1, and four passages 16b that open to the outer circumferential surface of the hub portion 12. Passage 16 supplies hydraulic fluid to the advance chamber AC and discharges hydraulic fluid from the advance chamber AC. The fitting recess 17 is formed as a cylindrical recess on the rear surface 10b side of the vane rotor 10 to fit the front end of the shaft portion 1a of the camshaft 1.

[0036] As shown in Figures 5 to 7, the seal groove 18 is a region where the seal member 60 and the biasing spring 70 are arranged, and extends in the axial direction S on the outer circumferential surface of each vane portion 11, penetrating from the front surface 10a to the rear surface 10b, and is formed to have a concave shape with both side surfaces 18a and a bottom surface 18b. The seal groove 18 is formed such that, on a plane perpendicular to the axis S, it includes a wide side surface 18a1 defining a first groove width W1 on the opening side, a narrow side surface 18a2 defining a second groove width W2 that is narrower than the first groove width W1 near the bottom surface 18b, and a stepped surface 18a3 connecting the wide side surface 18a1 and the narrow side surface 18a2. In other words, the seal groove 18 extends in the axial direction S and has a concave shape with both side surfaces 18a and a bottom surface 18b, and is formed so that both side surfaces 18a (between the wide side surface 18a1 and the narrow side surface 18a2) include a stepped surface 18a3 as a bent surface.

[0037] The positioning hole 19 is formed in the fitting recess 17 to open in the axial direction S in order to fit the positioning pin P1 which is fitted to the camshaft 1.

[0038] The vane rotor 10 is housed in the housing chamber C of the housing rotor 20 so as to be rotatable relative to a predetermined angular range, that is, within the angular range Δθ between the retarded position shown in Figure 12 and the advanced position shown in Figure 13, dividing the housing chamber C into a retarded chamber RC and an advanced chamber AC, and is fixed to the camshaft 1 by bolts B via annular spacers 30, and rotates integrally with the camshaft 1.

[0039] As shown in Figures 2 to 4, the housing rotor 20 has a two-part structure consisting of a bottomed cylindrical front housing 21 and a disc-shaped rear housing 22 that is connected to the front housing 21 by screws b. The housing rotor 20 then houses the vane rotor 10 so that it can rotate relative to it within a predetermined angular range (Δθ).

[0040] The front housing 21 is made of aluminum and is formed in a bottomed cylindrical shape that defines the housing chamber C. The front housing 21 includes a front wall 21a, a one-end locking portion 21b provided on the front wall 21a, a cylindrical wall 21c, an opening 21d, four screw holes 21e into which screws b are screwed, four shoe portions 21f, an inner circumferential surface 21g into which the sealing member 60 abuts, and an inner wall surface 21h.

[0041] The one-end locking portion 21b is a cylindrical pin with a flange that is fitted into a fitting hole formed in the front wall 21a of a region corresponding to one shoe portion 21f, and locks one end 51 of the rotation biasing spring 50. The one-end locking portion 21b plays the role of locking one end 51 in a usage configuration in which the rotation biasing spring 50 exerts a rotational biasing force in one direction around the axis S.

[0042] The opening 21d is formed in a circular shape with the axis S as the center, allowing the annular spacer 30 to pass through with a gap. The four shoe portions 21f are formed to protrude from the cylindrical wall 21c toward the center (axis S) and are arranged at equal intervals in the circumferential direction. The inner circumferential surface 21g is formed as part of a cylindrical surface centered on the axis S between the four shoe portions 21f, and is formed so that the contact surface 61a of the sealing member 60 contacts it by surface contact. The inner wall surface 21h is formed as a flat surface perpendicular to the axis S so that the front surface 10a of the vane rotor 10 and the end surface 61e of the sealing member 60 can slide into contact with it.

[0043] The rear housing 22 is formed in a disc shape as a sintered body made of an iron-based metal material and is equipped with a toothed row 22a, a mating inner circumferential surface 22b, four circular holes 22c through which the screw b passes, an inner wall surface 22d, a groove-shaped passage 22e, and a mating hole 22f.

[0044] The gear row 22a is formed so as to mesh with an interlocking member that rotates in conjunction with the crankshaft. The fitting inner circumferential surface 22b is rotatably fitted onto the shaft portion 1a of the camshaft 1. The inner wall surface 22d is formed as a flat surface perpendicular to the axis S so that the rear surface 10b of the vane rotor 10 and the end surface 61e of the sealing member 60 can slide into contact with it. The passage 22e is formed in a groove shape on the inner wall surface 22d and communicates with the passage 16 (passage 16b) in order to supply and discharge hydraulic fluid to and from the fitting hole 22f. The fitting hole 22f is formed on the inner wall surface 22d so that the lock pin 42 included in the locking mechanism 40 can be fitted into it.

[0045] The annular spacer 30 is formed as a sintered body of an iron-based material and, as shown in Figures 2 to 4, comprises a cylindrical portion 31 centered on the axis S, a bottom wall portion 32, a circular hole 33 through which a bolt B passes, a notch 34 formed in the cylindrical portion 31, and a positioning portion 35 formed in the bottom wall portion 32.

[0046] The cylindrical portion 31 is passed through the opening 21d of the front housing 21 with a gap between it and the recess 13a of the vane rotor 10, and is also press-fitted into the recess 13a of the vane rotor 10. The bottom wall portion 32 is joined to the bottom surface of the recess 13a of the vane rotor 10, and is formed so that the head of the bolt B abuts against it from the outside. The circular hole 33 is formed to an inner diameter dimension through which bolt B is passed. The notch 34 is formed by cutting out a part of the cylindrical portion 31 in the direction of the axis S, and functions as a locking portion that locks the other end 52 of the rotation biasing spring 50. The positioning section 35 positions the annular spacer 30 around the axis S relative to the vane rotor 10, and is formed as a slightly elongated hole in the radial direction to accommodate the positioning pin P2 fitted to the vane rotor 10.

[0047] As shown in Figure 4, the locking mechanism 40 includes a cylindrical holder 41, a locking pin 42, and a coil spring 43. The cylindrical holder 41 is fitted into the mounting hole 14 of the vane rotor 10 in order to hold the lock pin 42, which is biased by the coil spring 43, in a reciprocating manner. The lock pin 42 is reciprocally movable in the direction of the axis S, and is formed to protrude from the rear surface 10b of the vane rotor 10 by the biasing force of the coil spring 43 and fit into the fitting hole 22f of the rear housing 22, and to be embedded in the vane rotor 10 by receiving the hydraulic pressure of the hydraulic fluid guided into the fitting hole 22f or by receiving the hydraulic pressure of the hydraulic fluid guided through the passage 14b. The coil spring 43 exerts a biasing force in a direction that causes the lock pin 42 to protrude from the rear surface 10b of the vane rotor 10.

[0048] In the locking mechanism 40 having the above configuration, when the hydraulic pressure of the hydraulic fluid supplied through passages 16 and 22e decreases and the hydraulic pressure of the hydraulic fluid supplied through passage 14b decreases, the locking pin 42 engages with the fitting hole 22f of the housing rotor 20 by the biasing force of the coil spring 43, and the vane rotor 10 is locked to the retarded position relative to the housing rotor 20. On the other hand, when the hydraulic pressure of the hydraulic fluid supplied through passages 16 and 22e becomes greater than the biasing force of the coil spring 43, the lock pin 42 retracts from the rear surface 10b of the vane rotor 10, and the lock of the vane rotor 10 is released. Also, when the hydraulic pressure of the hydraulic fluid supplied through passage 14b becomes greater than the biasing force of the coil spring 43, the unlocked state is maintained.

[0049] The rotational biasing spring 50 is pre-formed into a spiral shape using a flat spring steel or similar material, and as shown in Figures 1 to 3, it is a spiral spring having one end 51 located at the outer circumference and the other end 52 at the inner circumference. The rotational biasing spring 50 is positioned along the front wall 21a, with one end 51 locked to one end locking portion 21b provided on the front wall 21a, and the other end 52 locked to the notch portion 34 of the annular spacer 30. In other words, the rotational biasing spring 50 is assembled with a set load that exerts a predetermined rotational biasing force on the housing rotor 20, such that the vane rotor 10 is rotated in one direction around the axis S, i.e., in the advance direction.

[0050] In this way, by employing a rotational biasing spring 50 that biases in the advance direction, rattling of the vane rotor 10 can be prevented, the required hydraulic pressure when advancing the angle can be reduced, and responsiveness can be improved. Furthermore, by setting the set load of the rotational biasing spring 50 so that the difference between the operating torque and the load torque is approximately the same during angle advance and angle retardation, controllability can be improved. In particular, since the rotational biasing spring 50 is a spiral spring, the dimension in the axial S direction is only the thickness dimension of the wire diameter, and therefore, the device can be made thinner and more compact in the axial S direction.

[0051] The sealing member 60 is molded from a resin material and, as shown in Figures 5, 6, and 8, is formed to be elongated in the axial direction S so as to be positioned in the sealing groove 18, and is equipped with a wide portion 61, a pair of narrow portions 62, a weight-reducing portion 63, two guide grooves 64, and two stepped portions 65.

[0052] The wide portion 61 defines a contact surface 61a, wide opposing surfaces 61b on both sides in a direction perpendicular to the axis S (around the axis S), stepped opposing surfaces 61c and 61d extending perpendicularly to the wide opposing surfaces 61b, and end surfaces 61e located at both ends in the direction of the axis S.

[0053] The contact surface 61a is formed to have the same curvature as or a slightly larger curvature than the inner peripheral surface 21g, and is in surface contact with the inner peripheral surface 21g of the housing rotor 20 so as to be closely abutted. The wide opposing surface 61b is formed to face the wide side surface 18a1 of the seal groove 18 with a gap C1 therebetween. The stepped opposing surface 61c is formed to face the stepped surface 18a3 of the seal groove 18 with a gap C2 therebetween. The stepped opposing surface 61d is formed on both end sides in the axial direction of the axis S, and is formed to face the stepped surface 18a3 of the seal groove 18 with a gap C3 (C3 < C2) therebetween. The end surface 61e is formed to be a substantially U-shaped flat surface that contacts the inner wall surfaces 21h and 22d of the housing rotor 20 and opens toward the bottom surface 18b side of the seal groove 18.

[0054] The narrow portion 62 defines narrow opposing surfaces 62b on both sides in the direction perpendicular to the axis S (around the axis S) and an end surface 62c located at the end in the axial direction of the axis S. The narrow opposing surface 62b is formed to face the narrow side surface 18a2 of the seal groove 18 with a gap C4 therebetween. The end surface 62c is formed as a flat surface perpendicular to the axis S that is recessed more than the end surface 61e in the axial direction of the axis S.

[0055] As shown in FIGS. 6, 8, and 11, the hollowed-out portion 63 is formed in a concave shape and extends in the axial direction of the axis S on the side facing the bottom surface 18b of the seal groove 18 in the region sandwiched between the pair of narrow portions 62, that is, on the side opposite to the contact surface 61a of the region of the wide portion 61. By providing the hollowed-out portion 63 in this way, the internal space IS sandwiched between the seal member 60 and the bottom surface 18b of the seal groove 18 can be made larger. Thereby, even when the working oil intrudes into the internal space IS from the retard chamber RC or the advance chamber AC through the gap C1, the velocity energy of the working oil can be reduced or eliminated due to the loss caused by the sudden expansion.

[0056] As shown in Figures 5, 6, and 8, the two guide grooves 64 are formed inside each of the pair of narrow sections 62, extending radially perpendicular to the axis S. The two guide grooves 64 are designed to slidably guide one end 72 and the other end 73, i.e., both ends, of the biasing spring 70.

[0057] The two stepped portions 65 are formed on both sides of the axis S, which is flanked by the contact surface 61a, and each extends in the direction of the axis S. They include an upright surface 65a oriented perpendicular to the inner circumferential surface 21g and a stepped surface 65b that is perpendicular to and continuous with the upright surface 65a. In this way, by providing the stepped portion 65, it is possible to suppress or prevent the hydraulic fluid from entering the contact interface between the contact surface 61a and the inner circumferential surface 21g.

[0058] As shown in Figures 5, 6, and 8, the biasing spring 70 is positioned in the seal groove 18 of the vane rotor 10 and biases the seal member 60 toward the inner circumferential surface 21g. Here, the biasing spring 70 is a leaf spring made of spring steel plate or the like, and has a width dimension slightly narrower than the second groove width W2 defined by the narrow side surface 18a2 of the seal groove 18. It is arranged to curve convexly toward the bottom surface 18b of the seal groove 18, and has a curved portion 71 formed such that the central region in the axial direction S curves convexly toward the opposite side of the bottom surface 18b, and has one end 72 and the other end 73. The biasing spring 70, when positioned in the seal groove 18 together with the seal member 60, contacts the bottom surface 18b at two locations (regions 71a, 71a) on both sides of the curved portion 71, and its one end 72 and the other end 73 are movably fitted into the guide grooves 64 on both ends of the seal member 60, thereby biasing the seal member 60 toward the inner circumferential surface 21g. In this way, since the biasing spring 70 contacts the bottom surface 18b at two locations (regions 71a, 71a) on either side of the curved portion 71, it can apply a uniform biasing force to the sealing member 60 without causing any tilting of the biasing spring 70.

[0059] In the relationship between the seal member 60 having the above configuration and the seal groove 18 of the vane rotor 10, as shown in Figures 9 to 11, the seal groove 18 is concave, extending in the axial direction S and having both sides 18a and a bottom surface 18b, and includes a bent surface (step surface 18a3) on both sides 18a (wide side 18a1, narrow side 18a2), ​​and the seal member 60 is formed to have a cross-sectional shape along both sides 18a (wide side 18a1, narrow side 18a2) including the bent surface (step surface 18a3), that is, to have a complementary shape.

[0060] Specifically, in the relationship between the seal groove 18 and the seal member 60, the gap C1 between the wide side surface 18a1 and the wide opposing surface 61b is formed to be smaller than the gap C4 between the narrow side surface 18a2 and the narrow opposing surface 62b. Furthermore, the gap C2 between the stepped surface 18a3 and the step-facing surface 61c is larger than the gap C1, i.e., C2 > C1. Furthermore, the gap C3 between the stepped surface 18a3 and the stepped surface 61d is formed to be larger than the gap C1 and smaller than the gap C2, i.e., C2 > C3 > C1.

[0061] Thus, since the seal groove 18 includes a bent surface (stepped surface 18a3) on both sides 18a (wide side 18a1, narrow side 18a2), ​​and the seal member 60 is formed to have a cross-sectional shape (complementary shape) along both sides 18a (wide side 18a1, narrow side 18a2) including the bent surface (stepped surface 18a3), the passage is formed as a bent passage with a labyrinth structure. As a result, it is possible to actively suppress or prevent the hydraulic fluid in the retarding chamber RC or the advancing chamber AC from flowing into the seal groove 18 through the gap C1. Furthermore, since the gap or volume of the passage between the seal groove 18 and the seal member 60 is formed such that gap C1 < gap C2, gap C1 < gap C3, gap C1 < gap C4, and gap C1 << internal space IS, when the hydraulic fluid enters the internal space IS of the seal groove 18 through gap C1, a loss occurs due to the expansion of the passage, which can reduce or dissipate the kinetic energy of the hydraulic fluid. This prevents, for example, the hydraulic fluid in the retarding chamber RC from flowing through one gap C1, through the internal space IS in the seal groove 18, and into the advancing chamber AC from the other gap C1, and also prevents the hydraulic fluid in the advancing chamber AC from flowing through one gap C1, through the internal space IS in the seal groove 18, and into the retarding chamber RC from the other gap C1. In particular, taking into consideration the viscosity of the hydraulic fluid actually used, it is preferable that the gap C1 between the wide side surface 18a1 and the wide opposing surface 61b be set in the range of 0.02 to 0.17 mm.

[0062] Next, the operation of the valve timing changing device M1 will be explained with reference to Figures 12 and 13. When the internal combustion engine is stopped, the hydraulic fluid in the retarding chamber RC and the advancing chamber AC is discharged, and the vane rotor 10 is positioned at the retarded position, as shown in Figure 12. Also, the locking pin 42 of the locking mechanism 40 is fitted into the fitting hole 22f, and the vane rotor 10 is locked relative to the housing rotor 20. This allows the internal combustion engine to start smoothly while preventing the vane rotor 10 from flapping or otherwise malfunctioning during startup.

[0063] Next, when the internal combustion engine is started, hydraulic fluid is supplied to the tip of the lock pin 42 through passages 16 and 22e, causing the lock pin 42 to be pressed and disengaged from the fitting hole 22f, releasing the lock. After the internal combustion engine is started, the hydraulic control valve 2a is switched as appropriate to perform phase control so that the vane rotor 10 and the camshaft 1 are advanced, retarded, or held at a predetermined angular position.

[0064] For example, in advance mode, the hydraulic fluid in the retard chamber RC is discharged through passages 15 and 2c, and hydraulic fluid is supplied to the advance chamber AC through passages 2b and 16. The vane rotor 10 is then rotated clockwise relative to the housing rotor 20, that is, toward the advance direction, by the hydraulic pressure of the hydraulic fluid in the advance chamber AC, and can rotate to the maximum advance position shown in Figure 13.

[0065] On the other hand, in retard mode, the hydraulic fluid in the advance chamber AC is discharged through passages 16 and 2b, and hydraulic fluid is supplied to the retard chamber RC through passages 2c and 15. The vane rotor 10 then rotates counterclockwise relative to the housing rotor 20, that is, toward the retard side, due to the hydraulic pressure of the hydraulic fluid in the retard chamber RC. Furthermore, as shown in Figure 12, when the vane rotor 10 moves to the retarded position, the lock pin 42 faces the fitting hole 22f. However, because the hydraulic fluid in the retarding chamber RC acts to embed the lock pin 42 through the passage 14b, the lock pin 42 does not engage with the fitting hole 22f, and the unlocked state is maintained.

[0066] Furthermore, in the holding mode, when the vane rotor 10 is held at an intermediate position between the most advanced and most retarded positions, the hydraulic control valve 2a is switched, and hydraulic fluid is supplied to the retarding chamber RC and the advancing chamber AC. The hydraulic pressure of the hydraulic fluid in the retarding chamber RC and the advancing chamber AC holds the vane rotor 10 at a predetermined intermediate position.

[0067] As described above, when the rotational phase angle of the vane rotor 10 relative to the housing rotor 20 is changed within a predetermined angular range, the seal member 60 is biased by the biasing force of the biasing spring 70 without being biased by the hydraulic pressure of the hydraulic fluid. As shown in Figure 14, while the amount of phase angle fluctuation is large in the case of conventional seal groove and seal member structures, the amount of phase angle fluctuation is small in the seal groove 18 and seal member 60 structure of the present invention, and the valve timing can be quickly controlled to the desired opening and closing timing.

[0068] Figures 15 to 21 show a part of the valve timing changing device M2 according to the second embodiment of the present invention. Components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted. As shown in Figure 15, the valve timing changing device M2 according to the second embodiment includes a vane rotor 110, a housing rotor 20, an annular spacer 30, a locking mechanism 40 for locking the vane rotor 110 against the housing rotor 20, a rotation biasing spring 50, a sealing member 160, and a biasing spring 70.

[0069] The vane rotor 110 is formed as a molded or forged product using an aluminum alloy or other metal material, and as shown in Figures 16 and 17, it has a front surface 10a and a rear surface 10b, four vane sections 11, a cylindrical hub section 12, a through hole 13, a recess 13a, a fitting hole 13b for fitting a positioning pin P2, a mounting hole 14 for attaching a locking mechanism 40, passages 15 and 16, a fitting recess 17 for fitting a camshaft 1, four seal grooves 118 formed at the tips of the four vane sections 11, and a positioning hole 19 for fitting a positioning pin P1 of the camshaft 1.

[0070] As shown in Figures 16 and 17, the seal groove 118 is a region where the seal member 160 and the biasing spring 70 are arranged. It extends in the axial direction S on the outer circumferential surface of each vane portion 11, penetrating from the front surface 10a to the rear surface 10b, and is formed to have a concave shape with both side surfaces 118a and a bottom surface 118b. Furthermore, both side surfaces 118a are formed to include recessed portions 118c that extend in the axial direction S and are recessed in a direction perpendicular to the axial direction S. The recessed portion 118c has a rectangular concave cross-section perpendicular to the axis S and is formed to include a pair of extending surfaces 118c1 extending perpendicularly from both sides 118a, and a rear end surface 118c2 that is continuous perpendicularly to the pair of extending surfaces 118c1. That is, the pair of extending surfaces 118c1 and the rear end surface 118c2 define a bent surface on both sides 118a.

[0071] The vane rotor 110 is housed in the housing chamber C of the housing rotor 20 so as to be rotatable relative to a predetermined angular range, that is, within the angular range Δθ between the retarded position shown in Figure 12 and the advanced position shown in Figure 13, dividing the housing chamber C into a retarded chamber RC and an advanced chamber AC, and is fixed to the camshaft 1 by bolts B via annular spacers 30, and rotates integrally with the camshaft 1.

[0072] The sealing member 160 is molded from a resin material and, as shown in Figures 18 to 21, is formed to be elongated in the axial direction S so as to be positioned in the sealing groove 118, and comprises an elongated portion 161, two convex portions 162 that are inserted into the recessed portion 118c, a pair of protruding portions 163, a weight-reducing portion 164, two guide grooves 165, and two stepped portions 166.

[0073] The elongated portion 161 defines a contact surface 61a, opposing surfaces 161b that are part of the opposing surfaces facing both sides 118a on both sides in a direction perpendicular to the axis S (around the axis S), and end surfaces 161c located at both ends in the direction of the axis S. The contact surface 161a has the same curvature as the inner circumferential surface 21g or a slightly larger curvature, and is formed to make close surface contact with the inner circumferential surface 21g of the housing rotor 20. The opposing surface 161b is formed to face both sides 118a of the seal groove 118 with a gap C1 between them. The end face 161c is formed to form a substantially U-shaped flat surface that contacts the inner wall surfaces 21h and 22d of the housing rotor 20 and opens toward the bottom surface 118b of the seal groove 118. Here, the end face 161c is formed extending from the elongated portion 161 to the convex portion 162 and the protruding portion 163.

[0074] The two protruding ridges 162 project from the opposing surface 161b on both sides of the elongated portion 161, and have a rectangular convex cross-section perpendicular to the axis S. Each of these is formed to include a pair of protruding opposing surfaces 162a facing a pair of extending surfaces 118c1, and a protruding end surface 162b that is perpendicular to the pair of protruding opposing surfaces 162a. The protruding opposing surface 162a is formed to face the extended surface 118c1 of the seal groove 118 with a gap C5 between them. The protruding end surface 162b is formed to face the inner end surface 118c2 of the seal groove 118 with a gap C6 between them. Here, the gap C5 between the extended surface 118c1 and the protruding opposing surface 162a is formed to be smaller than the gap C6 between the inner end surface 118c2 and the protruding end surface 162b.

[0075] The pair of protrusions 163 project toward the bottom surface 118b at both ends in the direction of the axis S, and define opposing surfaces 163a as part of the opposing surfaces facing both sides 118a on both sides in a direction perpendicular to the axis S (around the axis S). The opposing surface 163a is located on the same plane as the opposing surface 161b and is formed to face both sides 118a of the seal groove 118 with a gap C1 between them.

[0076] As shown in Figures 18, 20, and 21, the weight-reducing portion 164 is formed in a concave shape and extends in the axial direction S in the region sandwiched between the pair of protrusions 163, on the side facing the bottom surface 118b of the seal groove 118, that is, on the side opposite to the contact surface 161a of the elongated portion 161. In this way, by providing the weight-reducing portion 164, the internal space IS sandwiched between the sealing member 160 and the bottom surface 118b of the sealing groove 118 can be made larger. As a result, even if the hydraulic fluid enters the internal space IS through the gap C1 from the retarding chamber RC or the advancing chamber AC, the loss due to rapid expansion can reduce or dissipate the kinetic energy of the hydraulic fluid.

[0077] As shown in Figures 18 and 20, the two guide grooves 165 are formed inside each of the pair of protrusions 163, extending radially perpendicular to the axis S. The two guide grooves 165 are designed to slidably guide one end 72 and the other end 73, i.e., both ends, of the biasing spring 70.

[0078] The two stepped portions 166 are formed on both sides of the axis S flanking the contact surface 161a, extending in the direction of the axis S, and each includes an upright surface 166a oriented perpendicular to the inner circumferential surface 21g, and a stepped surface 166b that is perpendicular and continuous with the upright surface 166a. By providing these stepped portions 166, it is possible to suppress or prevent hydraulic fluid from entering the contact interface between the contact surface 161a and the inner circumferential surface 21g.

[0079] In the relationship between the seal member 160 and the seal groove 118 of the vane rotor 110, as shown in Figures 19 to 21, the seal groove 118 is concave, extending in the axial direction S and having both sides 118a and a bottom surface 118b, and includes bent surfaces (a pair of extended surfaces 118c1 and a rear end surface 118c2) on both sides 118a, and the seal member 160 is formed to have a cross-sectional shape along both sides 118a including the bent surfaces (a pair of extended surfaces 118c1 and a rear end surface 118c2), that is, to have a complementary shape.

[0080] Specifically, the convex portion 162 of the sealing member 160 is formed to be inserted into the concave portion 118c of the sealing groove 118. Furthermore, the gap C1 between both side surfaces 118a and the opposing surface 161b is formed to be smaller than the gaps C5 and C6 between the recessed portion 118c and the protruding portion 162 (the gap C5 between the extended surface 118c1 and the protruding opposing surface 162a, and the gap C6 between the inner end surface 118c2 and the protruding end surface 162b). Furthermore, the gap C5 between the extended surface 118c1 and the protruding opposing surface 162a is formed to be smaller than the gap C6 between the inner end surface 118c2 and the protruding end surface 162b.

[0081] Thus, since the seal groove 118 includes bent surfaces (a pair of extended surfaces 118c1 and a rear end surface 118c2) on both sides 118a, and the seal member 160 is formed to have a cross-sectional shape (complementary shape) along both sides 118a that include the bent surfaces (a pair of extended surfaces 118c1 and a rear end surface 118c2), the passage is formed as a bent passage with a labyrinth structure. As a result, it is possible to actively suppress or prevent the hydraulic fluid in the retarding chamber RC or the advancing chamber AC from flowing into the seal groove 118 through the gap C1. Furthermore, since the gap or volume of the passage between the seal groove 118 and the seal member 160 is formed such that gap C1 < gap C5 < gap C6 and gap C1 << internal space IS, when the hydraulic fluid enters the internal space IS of the seal groove 118 through gap C1, a loss occurs due to the expansion of the passage, which can reduce or dissipate the kinetic energy of the hydraulic fluid. This prevents, for example, the hydraulic fluid in the retarding chamber RC from flowing through one gap C1, through the internal space IS in the seal groove 118, and into the advancing chamber AC from the other gap C1. It also prevents the hydraulic fluid in the advancing chamber AC from flowing through one gap C1, through the internal space IS in the seal groove 118, and into the retarding chamber RC from the other gap C1. In particular, taking into consideration the viscosity of the hydraulic fluid actually used, it is preferable that the gap C1 between both side surfaces 118a and the opposing surface 161b be set in the range of 0.02 to 0.17 mm.

[0082] The operation of the valve timing changing device M2 having the above configuration is the same as the operation shown in Figures 12 and 13 described in the first embodiment. Furthermore, when the rotational phase angle of the vane rotor 110 relative to the housing rotor 20 is changed within a predetermined angular range, the seal member 160 is biased by the biasing force of the biasing spring 70 without being biased by the hydraulic pressure of the hydraulic fluid. As shown in Figure 14, while the amount of phase angle fluctuation is large in the case of a conventional seal groove and seal member structure, the amount of phase angle fluctuation is small in the seal groove 118 and seal member 160 structure of the present invention, and the valve timing can be quickly controlled to the desired opening and closing timing.

[0083] As described above, the valve timing changing devices M1 and M2 having the above configuration are valve timing changing devices that change the opening and closing timing of an intake valve or exhaust valve driven by a camshaft 1, and include a housing rotor 20 that is rotatable around the axis S of the camshaft 1, vane rotors 10 and 110 that are rotatable relative to the housing rotor 20 within a predetermined angular range and rotate integrally with the camshaft 1 and have seal grooves 18 and 118 formed therein, and housing rotors arranged in the seal grooves 18 and 118 The grouter 20 is equipped with sealing members 60, 160 that abut against the inner circumferential surface 21g, and biasing springs 70 arranged in the sealing grooves 18, 118 that bias the sealing members 60, 160 toward the inner circumferential surface 21g. The sealing grooves 18, 118 extend in the axial direction S and have a concave shape with both side surfaces 18a, 118a and bottom surfaces 18b, 118b, and both side surfaces 18a, 118a include bent surfaces (step surface 18a3, a pair of extended surfaces 118c1 and a back end surface 118c2). The sealing members 60, 160 have a cross-sectional shape that follows both sides including the bent surfaces. According to this, a labyrinth structure is formed between both sides of the seal grooves 18, 118 and the seal members 60, 160. This suppresses or prevents the hydraulic fluid in the retarding chamber RC or advancing chamber AC from entering the seal grooves 18, 118, thereby preventing the hydraulic pressure of the hydraulic fluid from affecting the seal members 60, 160. This prevents overshoot and hunting phenomena during phase angle changes, as seen in conventional designs, and allows for quick control of valve timing.

[0084] Furthermore, the seal groove 18 includes a wide side surface 18a1 defining a first groove width W1 on the opening side, a narrow side surface 18a2 defining a second groove width W2 that is narrower than the first groove width W1 near the bottom surface 18b, and a stepped surface 18a3 connecting the wide side surface 18a1 and the narrow side surface 18a2 to define a bent surface. The seal member 60 includes a wide opposing surface 61b facing the wide side surface 18a1, a narrow opposing surface 62b facing the narrow side surface 18a2, and stepped opposing surfaces 61c and 61d facing the stepped surface 18a3. According to this, when the hydraulic fluid enters the seal groove 18 from the retarding chamber RC or the advancing chamber AC, in addition to the labyrinth structure, losses occur due to the expansion of the passage, which can reduce or dissipate the kinetic energy of the hydraulic fluid.

[0085] Furthermore, the gap C1 between the wide side surface 18a1 and the wide opposing surface 61b is smaller than the gap C4 between the narrow side surface 18a2 and the narrow opposing surface 62b. According to this, when the hydraulic fluid moves from gap C1 through gap C4 to the internal space IS, a loss occurs in the region from gap C1 to gap C4 due to the expansion of the gap, which can reduce or dissipate the kinetic energy of the hydraulic fluid.

[0086] Furthermore, the sealing member 60 includes a wide portion 61 defining a wide opposing surface 61b, a pair of narrow portions 62 extending from the wide portion 61 toward the bottom surface 18b at both ends in the axial direction S and defining a narrow opposing surface 62b, and a weight-reducing portion 63 on the side facing the bottom surface 18b in the region sandwiched between the pair of narrow portions 62. According to this, by forming the sealing member 60 in the above form, a structure that cooperates with the sealing groove 18 to create a labyrinth structure and loss due to passage expansion can be easily defined, and the biasing spring 70 can be easily positioned between the sealing member 60 and the bottom surface 18b.

[0087] Furthermore, the sealing member 60 includes guide grooves 64 inside the pair of narrow portions 62 that guide both ends (one end 72, the other end 73) of the biasing spring 70. According to this, the sealing member 60 can position the biasing spring 70 in a predetermined position, and the biasing spring 70 can be held in an elastically deformable manner.

[0088] Furthermore, by setting the gap C1 between the wide side surface 18a1 and the wide opposing surface 61b to a range of 0.02 to 0.17 mm, it is possible to allow movement of the sealing member 60 while suppressing or preventing the hydraulic fluid from entering through the gap C1, taking into consideration the viscosity of the hydraulic fluid actually used.

[0089] Furthermore, the seal groove 118 includes recessed portions 118c on both sides 118a that extend in the direction of the axis S to define the bent surface and are recessed in a direction perpendicular to the axis S, and the seal member 160 includes opposing surfaces 161b and 163a that face both sides 118a, and a convex portion 162 that is inserted into the recessed portion 118c. According to this, a more effective labyrinth structure can be created to suppress or prevent hydraulic fluid from entering the seal groove 118 from the retarding chamber RC or the advancing chamber AC.

[0090] Furthermore, the recessed portion 118c is formed such that the cross section perpendicular to the axis S is rectangular concave, and the convex portion 162 is formed such that the cross section perpendicular to the axis S is rectangular convex. According to this, with the convex portion 162 inserted into the concave portion 118c, a labyrinth structure is defined in which the passage bends at right angles three times, thereby efficiently suppressing or preventing the hydraulic fluid in the retarding chamber RC or the advancing chamber AC from entering the seal groove 118, and preventing the hydraulic pressure of the hydraulic fluid from affecting the seal member 160.

[0091] Furthermore, the gap C1 between both side surfaces 118a and the opposing surfaces 161b, 163a is formed to be smaller than the gaps C5, C6 between the recessed portion 118c and the convex portion 162. According to this, when the hydraulic fluid moves from gap C1 through gaps C5 and C6 to the internal space IS, a loss occurs in the region from gap C1 to gaps C5 and C6 due to the expansion of the gaps, which can reduce or dissipate the kinetic energy of the hydraulic fluid.

[0092] Furthermore, the recessed portion 118c includes a pair of extending surfaces 118c1 that extend perpendicularly from both sides 118a and a rear end surface 118c2 that is perpendicular to the pair of extending surfaces 118c1, and the convex portion 162 includes a pair of protruding opposing surfaces 162a that face the pair of extending surfaces 118c1 and a protruding end surface 162b that is perpendicular to the pair of protruding opposing surfaces 162a, and the gap C5 between the extending surface 118c1 and the protruding opposing surfaces 162a is formed to be smaller than the gap C6 between the rear end surface 118c2 and the protruding end surface 162b. According to this, as the hydraulic fluid moves from gap C5 through gap C6 towards the internal space IS, a loss occurs in the region from gap C5 to gap C6 due to the expansion of the gap, thereby reducing or dissipating the kinetic energy of the hydraulic fluid.

[0093] Furthermore, the sealing member 160 is formed to include an elongated portion 161 that defines a part of the opposing surface (opposing surface 161b) facing both sides 118a, a protruding portion 162 that protrudes from the opposing surface 161b on both sides of the elongated portion 161, a pair of protruding portions 163 that protrude toward the bottom surface 118b side than the protruding portion 162 at both ends in the axial direction S and define a part of the opposing surface (opposing surface 163a) facing both sides 118a, and a weight-reducing portion 164 on the side facing the bottom surface 118b in the region sandwiched between the pair of protruding portions 163. According to this, by forming the sealing member 160 in the above form, a structure that cooperates with the sealing groove 118 to create a labyrinth structure and loss due to passage expansion can be easily defined, and the biasing spring 70 can be easily positioned between the sealing member 160 and the bottom surface 118b.

[0094] Furthermore, the sealing member 160 includes guide grooves 165 inside the pair of protrusions 163 that guide both ends (one end 72, the other end 73) of the biasing spring 70. According to this, the biasing spring 70 can be positioned in a predetermined location by the sealing member 160, and the biasing spring 70 can be held in an elastically deformable manner.

[0095] Furthermore, by setting the gap C1 between both side surfaces 118a and the opposing surfaces 161b and 163a to a range of 0.02 to 0.17 mm, it is possible to allow movement of the sealing member 160 while preventing the hydraulic fluid from entering through the gap C1, taking into account the viscosity of the hydraulic fluid actually used.

[0096] Furthermore, the biasing spring 70 is formed as a leaf spring that is curved convexly toward the bottom surfaces 18b and 118b of the seal grooves 18 and 118. According to this, the desired biasing force can be obtained while forming the biasing spring 70 in a simple form.

[0097] Furthermore, the biasing spring 70 includes a curved portion 71 formed such that its central region is convex in the direction of the axis S, away from the bottom surfaces 18b and 118b, and is positioned to contact the bottom surfaces 18b and 118b at two locations (regions 71a, 71a) on either side of the curved portion 71. This allows for a uniform biasing force to be applied to the sealing members 60 and 160 without causing the biasing spring 70 to tilt or otherwise bend.

[0098] Furthermore, the sealing members 60 and 160 include stepped portions 65 and 166 that extend in the direction of the axis S on both sides of the contact surfaces 61a and 161a that contact the inner circumferential surface 21g of the housing rotor 20, with respect to the axis S. According to this, it is possible to suppress or prevent the hydraulic fluid in the retarding chamber RC or the advancing chamber AC from entering the contact interface between the contact surfaces 61a, 161a and the inner circumferential surface 21g.

[0099] Furthermore, the stepped portions 65 and 166 are formed to include upright surfaces 65a and 166a oriented perpendicular to the inner circumferential surface 21g, and downward-sloping surfaces 65b and 166b that are perpendicular to and continuous with the upright surfaces 65a and 166a. According to this configuration, the structure includes upright surfaces 65a and 166a that are perpendicular to the contact interface between the abutment surfaces 61a and 161a and the inner circumferential surface 21g, thereby more effectively preventing the hydraulic fluid from entering the contact interface.

[0100] Furthermore, since the sealing members 60 and 160 are formed from a resin material, they can be easily formed into the desired shape in cooperation with the sealing grooves 18 and 118 to define a labyrinth structure while achieving weight reduction.

[0101] In the above embodiment, the seal grooves 18 and 118 are shown as having a concave shape extending in the axial direction S and having both sides and a bottom surface, and including bent surfaces on both sides, and the seal members 60 and 160 are shown as having a cross-sectional shape that follows both sides including the bent surfaces. However, the embodiment is not limited to this, and other forms of seal grooves and seal members may be used as long as they have a labyrinth structure.

[0102] In the above embodiment, a housing rotor 20 having a two-part structure consisting of a front housing 21 and a rear housing 22 was shown as the housing rotor, but it is not limited to this. For example, the present invention may be adopted in a configuration that includes a housing rotor having a three-part structure consisting of a flat front housing, a cylindrical outer housing, and a flat rear housing, or other forms.

[0103] In the above embodiment, a spiral spring 50 was shown as the rotational biasing spring, but it is not limited to this, and a torsion coil spring may also be used as the rotational biasing spring. In the above embodiment, a locking mechanism 40 was shown that includes a cylindrical holder 41, a locking pin 42, and a coil spring 43, and locks to the retarded position, but it is not limited to this. For example, other locking mechanisms may be used as long as they can lock the vane rotors 10 and 110 to the housing rotor 20, and the locking position is not limited to the retarded position, but may be the advanced position or other intermediate positions.

[0104] As described above, the valve timing changing device of the present invention can suppress or prevent leakage of hydraulic fluid around the sealing member, thereby preventing overshoot and hunting phenomena during phase angle changes, and can quickly control valve timing. Therefore, it is not only applicable to internal combustion engines mounted on automobiles, but is also useful in small internal combustion engines mounted on motorcycles, and internal combustion engines mounted on other vehicles or ships. [Explanation of Symbols]

[0105] 1 camshaft S axis M1 Valve Timing Adjustment Device 10 vane rotor 10a front 10b Rear 11. Vane section 12 Hub section 13 Through hole 14 mounting holes 15, 16 aisle 17 Fitting recess 18 seal groove 18a Both sides 18a1 Wide side W1 First groove width 18a2 narrow side W2 Second groove width 18a3 stepped surface (bent surface) 18b Base 19 Positioning holes 20 Housing Rotors C Confinement Chamber 21 Front Housing 21a Front wall 21b One end locking part 21c Cylindrical wall 21d opening 21e screw hole 21f Shoe section 21g Inner surface 21h Inner wall surface 22 Rear housing 22a Dentition 22b Fitting inner circumferential surface 22c circular hole 22d Interior wall surface 22e aisle 22f Fitting hole 30 Annular Spacers 31 Cylindrical section 32 Bottom wall section 33 Round hole 34 Notch 35 Positioning section 40 Locking mechanism 41 Cylindrical holder 42 lock pins 43 Coil spring 50 rotation biasing spring 60 sealing member 61 Wide section 61a Contact surface 61b Wide opposing surface C1 Gap between wide side and wide opposing surface 61c, 61d Step-facing surfaces C2, C3 Gap between the stepped surface and the surface opposite the stepped surface 61e End face 62 Narrow part 62b Narrow opposite surface C4 Gap between narrow side and narrow opposing surface 62c end face 63. Weight reduction section 64 Guide grooves 65 Step section 65a Upright side 65b Step-down surface 70. Biasing spring (leaf spring) 71 Curved section 71a Two locations on either side of the curved section 72 One end 73 Other end M2 Valve Timing Adjustment Device 110 vane rotor 118 Seal groove 118a Both sides 118b Bottom 118c Concave section 118c1 A pair of extended surfaces (bent surfaces) 118c2 Back end surface (bent surface) 160 sealing member 161 Long section 161a Contact surface 161b Opposing surface (part of the opposing surface that faces both sides) C1 Gap between both sides and the opposing surface 162 Convex part 162a A pair of opposing protruding surfaces 162b Protruding surface C5 Gap between the extended surface and the opposing protruding surface C6 Gap between the inner end face and the outer end face 163 Pair of protrusions 163a Opposing surface (a portion of the opposing surface that faces both sides) 164 Weight-reducing section 165 Guide groove 166 Stepped section 166a Upright surface 166b Step-down surface

Claims

1. A valve timing changing device for changing the opening and closing timing of an intake valve or exhaust valve driven by a camshaft, comprising: a housing rotor rotatable around the axis of the camshaft; a vane rotor rotatable relative to the housing rotor within a predetermined angular range and rotating integrally with the camshaft, and having a seal groove formed therein; a seal member disposed in the seal groove and in contact with the inner circumferential surface of the housing rotor; and a biasing spring disposed in the seal groove and biasing the seal member toward the inner circumferential surface, The seal groove extends in the axial direction of the camshaft and has a concave shape with both sides and a bottom surface, and includes a bent surface on both sides. The sealing member has a cross-sectional shape that extends along both sides including the bent surface. A valve timing changing device characterized by the following features.

2. The seal groove includes a wide side surface defining a first groove width on the opening side, a narrow side surface defining a second groove width narrower than the first groove width near the bottom surface, and a stepped surface connecting the wide side surface and the narrow side surface to define the curved surface. The sealing member includes a wide opposing surface facing the wide side surface, a narrow opposing surface facing the narrow side surface, and a stepped opposing surface facing the stepped surface. The valve timing changing device according to feature 1.

3. The gap between the wide side and the wide opposing surface is smaller than the gap between the narrow side and the narrow opposing surface. The valve timing changing device according to feature 2.

4. The sealing member includes a wide portion defining the wide opposing surface, a pair of narrow portions extending from the wide portion toward the bottom surface at both ends in the axial direction and defining the narrow opposing surface, and a weight-reducing portion on the side facing the bottom surface in the region sandwiched between the pair of narrow portions. The valve timing changing device according to feature 2.

5. The sealing member includes guide grooves inside the pair of narrow portions that guide both ends of the biasing spring, The valve timing changing device according to feature 4.

6. The gap between the wide side surface and the wide opposing surface is 0.02 to 0.17 mm. The valve timing changing device according to feature 3.

7. The seal groove includes, on both sides, a recessed portion that extends in the axial direction to define the bent surface and is recessed in a direction perpendicular to the axis. The sealing member includes opposing surfaces facing the two side surfaces and a protruding portion inserted into the recessed portion. The valve timing changing device according to feature 1.

8. The aforementioned groove portion has a rectangular concave shape in cross-section perpendicular to the axis, The aforementioned protruding portion has a rectangular convex shape in cross-section perpendicular to the axis. The valve timing changing device according to feature 7.

9. The gap between the two aforementioned sides and the opposing surface is smaller than the gap between the recessed portion and the convex portion. The valve timing changing device according to feature 7.

10. The groove portion includes a pair of extending surfaces that extend perpendicularly from both sides and a back end surface that is continuous perpendicularly to the pair of extending surfaces. The aforementioned protruding portion includes a pair of protruding opposing surfaces facing the pair of extending surfaces, and a protruding end surface that is continuous perpendicularly to the pair of protruding opposing surfaces. The gap between the extended surface and the protruding opposing surface is smaller than the gap between the inner end surface and the protruding end surface. The valve timing changing device according to feature 7.

11. The sealing member includes an elongated portion defining a part of the opposing surface, protruding portions on both sides of the elongated portion that project from the opposing surface, a pair of protruding portions on both ends in the axial direction that project toward the bottom surface than the protruding portions and define a part of the opposing surface, and a weight-reducing portion on the side facing the bottom surface in the region sandwiched between the pair of protruding portions. The valve timing changing device according to feature 7.

12. The sealing member includes guide grooves inside the pair of protrusions that guide both ends of the biasing spring, The valve timing changing device according to feature 11.

13. The gap between the two aforementioned sides and the opposing surface is 0.02 to 0.17 mm. The valve timing changing device according to feature 7.

14. The biasing spring is a leaf spring arranged to curve convexly toward the bottom surface of the seal groove. The valve timing changing device according to feature 1.

15. The biasing spring includes a curved portion formed such that its central region in the axial direction is convexly curved toward the opposite side of the bottom surface, and is arranged to contact the bottom surface at two locations on both sides of the curved portion. The valve timing changing device according to feature 14.

16. The sealing member includes stepped portions extending in the axial direction on both sides of the axis, with respect to the contact surface that abuts the inner circumferential surface of the housing rotor. A valve timing changing device according to any one of features 1 to 15.

17. The stepped portion includes an upright surface oriented perpendicular to the inner circumferential surface and a downward-sloping surface that is continuous perpendicular to the upright surface. The valve timing changing device according to feature 16.

18. The sealing member is formed of a resin material. The valve timing changing device according to feature 16.

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