JP7539599B2 - Valve timing adjustment device - Google Patents

Description

The present disclosure relates to a valve timing adjustment device.

A valve timing adjustment device has been disclosed that is provided in a drive force transmission system that transmits the drive force of an internal combustion engine from a crankshaft to a camshaft, and adjusts the opening and closing timing of at least one of an intake valve and an exhaust valve that are driven to open and close by the camshaft (see Patent Document 1). This valve timing adjustment device includes a housing that rotates with the crankshaft, a vane rotor that is rotatable relative to the housing and rotates with the crankshaft, and a first stopper piston and a second stopper piston that restrict the relative rotation of the vane rotor with respect to the housing. In addition, this valve timing adjustment device moves the first stopper piston and the second stopper piston by changing the pressure of the hydraulic oil supplied, and switches between a state in which the relative rotation of the vane rotor with respect to the housing is restricted and a state in which the vane rotor is rotatable relative to the housing.

JP 2014-152671 A

Generally, in a valve timing adjustment device such as that described in Patent Document 1, multiple oil passages, including a hydraulic oil passage for rotating the vane rotor relative to the housing and a hydraulic oil passage for moving the stopper piston, are formed independently of each other, which tends to make the structure of the device complex. For this reason, there is a demand for a simplified structure of the valve timing adjustment device.

The present disclosure aims to solve the above-mentioned problems and provide a valve timing adjustment device that can be simplified in structure compared to conventional devices.

The valve timing adjusting device according to the present disclosure includes a first rotor that rotates following the rotation of a crankshaft of an internal combustion engine, a second rotor that is rotatably supported relative to the first rotor between a first position and a second position and rotates together with the first rotor to transmit a rotational force of the first rotor to a camshaft that opens and closes a valve of the internal combustion engine, a rotation limiting member that moves between a limiting position that limits the rotation of the second rotor relative to the first rotor when the second rotor is located at a third position between the first position and the second position and an allowing position that allows the rotation of the second rotor relative to the first rotor, a first valve that switches between a state that allows the transmission of pressure of the working fluid between the first space and the third space and a state that restricts the transmission of pressure of the working fluid between the first space and the third space, and a rotation limiting member that allows the transmission of pressure of the working fluid between the second space and the third space. and a second valve that switches between a state in which the pressure of the working fluid is transmitted between the second space and the third space, the first rotating body forming a first space and a second space to which the pressure of the working fluid is transmitted between the first rotating body and the second rotating body, the second rotating body rotating between a first position and a second position due to a pressure difference of the working fluid between the first space and the second space, the rotation limiting member being arranged so as to be exposed to the third space through which the pressure of the working fluid from the first space and the second space can be transmitted, and moving between the restricting position and the allowing position due to a change in the pressure of the working fluid transmitted to the third space , and when the rotation limiting member is positioned in the restricting position and the pressure of the working fluid transmitted to the third space is transmitted from at least one of the first space and the second space to the third space, the rotation limiting member moves from the restricting position to the allowing position due to the pressure of the working fluid transmitted to the third space .

According to the present disclosure, the rotation limiting member that limits the rotation of the second rotating body is configured to be moved by changes in pressure in the space to which the pressure of the working fluid for rotating the second rotating body is transmitted, thereby simplifying the structure compared to a case in which the flow path of the working fluid for rotating the second rotating body and the flow path of the working fluid for moving the rotation limiting member are formed independently of each other.

1 is a cross-sectional view showing a schematic configuration of a valve timing adjusting device according to a first embodiment. FIG. 2A is a diagram showing a valve timing adjustment device of embodiment 1, and is a front view showing the appearance when hydraulic pressure is not being transmitted, and FIG. 2B is a diagram showing a valve timing adjustment device of embodiment 1, and is a front view showing the internal structure when hydraulic pressure is not being transmitted. 2B is a cross-sectional view showing the valve timing adjusting device according to the first embodiment, taken along line AA in FIG. 2B. FIG. 4A is a diagram showing a valve timing adjustment device of embodiment 1, and is a front view showing the appearance when oil pressure is transmitted to the first oil passage and the second oil passage. FIG. 4B is a diagram showing a valve timing adjustment device of embodiment 1, and is a front view showing the internal structure when oil pressure is transmitted to the first oil passage and the second oil passage. 4B is a cross-sectional view showing the valve timing adjusting device according to the first embodiment, taken along line AA in FIG. 4B. FIG. 6A is a diagram showing a valve timing adjustment device of embodiment 1, and is a front view showing the appearance when oil pressure is transmitted to the first oil passage, and FIG. 6B is a diagram showing a valve timing adjustment device of embodiment 1, and is a front view showing the internal structure when oil pressure is transmitted to the first oil passage. 6B is a cross-sectional view showing the valve timing adjusting device according to the first embodiment, taken along line AA in FIG. 6B. Figure 8A shows a valve timing adjustment device of embodiment 1, and is a front view showing the appearance when oil pressure is transmitted to the second oil passage, and Figure 8B shows a valve timing adjustment device of embodiment 1, and is a front view showing the internal structure when oil pressure is transmitted to the second oil passage. 8B is a cross-sectional view showing the valve timing adjusting device according to the first embodiment, taken along line AA in FIG. 8B. FIG. 10A is a diagram showing a valve timing adjustment device of embodiment 2, and is a front view showing the appearance when hydraulic pressure is not being transmitted, and FIG. 10B is a diagram showing a valve timing adjustment device of embodiment 2, and is a front view showing the internal structure when hydraulic pressure is not being transmitted. FIG. 10C is an enlarged view showing the valve timing adjusting device according to the second embodiment, and is an enlarged view of D in FIG. 10B. 10B is a cross-sectional view showing the valve timing adjusting device according to the second embodiment, taken along line HH in FIG. 10B. Figure 13A is a diagram showing a valve timing adjustment device of embodiment 2, and is a front view showing the appearance when oil pressure is transmitted to the first oil passage and the second oil passage, and Figure 13B is a diagram showing a valve timing adjustment device of embodiment 2, and is a front view showing the internal structure when oil pressure is transmitted to the first oil passage and the second oil passage. FIG. 13C is an enlarged view showing the valve timing adjusting device according to the second embodiment, and is an enlarged view of D in FIG. 13B. Figure 15A shows a valve timing adjustment device of embodiment 2, and is a front view showing the appearance when oil pressure is transmitted to the first oil passage, and Figure 15B shows a valve timing adjustment device of embodiment 2, and is a front view showing the internal structure when oil pressure is transmitted to the first oil passage. FIG. 15C is an enlarged view showing the valve timing adjusting device according to the second embodiment, and is an enlarged view of D in FIG. 15B. Figure 17A shows a valve timing adjustment device of embodiment 2, and is a front view showing the appearance when oil pressure is transmitted to the second oil passage, and Figure 17B shows a valve timing adjustment device of embodiment 2, and is a front view showing the internal structure when oil pressure is transmitted to the second oil passage. FIG. 17C is an enlarged view showing the valve timing adjusting device according to the second embodiment, and is an enlarged view of D in FIG. 17B. 13 is a front view showing an internal structure of a valve timing adjusting device according to a third embodiment in a state in which hydraulic pressure is not transmitted. FIG. FIG. 20 is an enlarged view showing a valve timing adjusting device according to a third embodiment, taken along line D in FIG. 19 .

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.
Embodiment 1.
First, a schematic configuration of a valve timing adjusting device 100A according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing a schematic configuration of the valve timing adjusting device 100A according to the first embodiment. The valve timing adjusting device 100A includes a housing 10 that rotates following the rotation of a crankshaft (not shown) of an internal combustion engine (not shown), a rotor 20 that transmits the rotational force of the housing 10 to a camshaft 2 that opens and closes a valve (not shown) of the internal combustion engine, a spiral spring 31 (see Fig. 2A), a lock pin 32 (see Fig. 2B), a lock pin spring 33 (see Fig. 3), and an oil control valve 50 that controls the oil pressure acting on the valve timing adjusting device 100A.

The housing 10 has a sprocket portion 11 to which the rotational force of the crankshaft is transmitted by, for example, an endless roller chain (not shown), and rotates about the rotation axis L1 following the rotation of the crankshaft. The housing 10 may have a toothed pulley and be configured so that the rotational force of the crankshaft is transmitted by an endless toothed belt. In the first embodiment, the housing 10 constitutes a first rotating body. Details of the housing 10 will be described later.

The rotor 20 is supported on the housing 10 so as to be rotatable within a predetermined angle range around the rotation axis L1. The rotor 20 is fastened to the camshaft 2 by a center bolt. The rotor 20 receives rotational force from the housing 10 and rotates integrally with the camshaft 2, thereby transmitting the rotational force of the housing 10 to the camshaft 2. The rotor 20 changes its rotational position relative to the housing 10 due to hydraulic pressure transmitted from an oil pump (not shown) via an oil control valve (OCV) 50. In the first embodiment, the rotor 20 constitutes a second rotating body. Details of the rotor 20 will be described later.

The spiral spring 31 generates torque on the rotor 20 relative to the housing 10 with one end held by the housing 10 and the other end held by the rotor 20. Details of the spiral spring 31 will be described later. The lock pin 32 is supported by the rotor 20 so as to be movable along the rotation axis L1 between a limiting position that limits the rotation of the rotor 20 relative to the housing 10 and an allowing position that allows the rotation of the rotor 20 relative to the housing 10. The lock pin spring 33 biases the lock pin 32 from the allowing position toward the limiting position. In the first embodiment, the lock pin 32 constitutes a rotation limiting member. Details of the lock pin 32 and the lock pin spring 33 will be described later.

The OCV 50 has a sleeve 51, a spool 52 housed inside the sleeve 51 and moving relative to the sleeve 51, a drive unit (not shown) that drives the spool 52, and a spool spring 53. For example, the OCV 50 is disposed along the rotation axis L1 and rotates integrally with the rotor 20 and the camshaft 2. Note that the OCV 50 is not limited to one that rotates integrally with the rotor 20 and the camshaft 2, and the OCV may be disposed with a gap between the housing 10 and the rotor 20 and connected to the housing 10 and the rotor 20 via a hydraulic pipe that can transmit the pressure of the hydraulic oil (hereinafter also referred to as "hydraulic pressure").

For example, the sleeve 51 is formed in a cylindrical shape along the rotation axis L1 and has a plurality of through holes including an input port, an output port, and an exhaust port formed at different positions in the direction along the rotation axis L1.

For example, the spool 52 is supported so as to be movable linearly along the rotation axis L1 relative to the sleeve 51. Also, for example, the drive unit is constituted by a solenoid that operates upon receiving a supply of electric current. The spool 52 moves relative to the sleeve 51 due to the drive force from the drive unit and the reaction force of the spool spring 53 acting in the opposite direction to the drive force. By moving relative to the sleeve 51, the spool 52 switches between the oil passages that communicate with the through hole of the sleeve 51 and the oil passages that are cut off, thereby connecting and disconnecting the hydraulic pressure input to the OCV 50, switching the output destination of the hydraulic pressure input to the OCV 50, and discharging the hydraulic oil in each oil passage.

Thus configured, the OCV 50 controls the hydraulic pressure transmitted to the first oil passage S1 and the second oil passage S2 (see FIG. 3) formed inside the valve timing adjustment device 100A. In other words, the OCV 50 controls the pressure difference between the first oil passage S1 and the second oil passage S2 formed inside the valve timing adjustment device 100A. For example, the OCV 50 switches the hydraulic pressure transmitted to the first oil passage S1 and the second oil passage S2 between an initial state in which hydraulic pressure is transmitted to both the first oil passage S1 and the second oil passage S2, an advanced state in which hydraulic pressure is transmitted to the first oil passage S1 and the hydraulic oil in the second oil passage S2 is discharged, and a retarded state in which hydraulic pressure is transmitted to the second oil passage S2 and the hydraulic oil in the first oil passage S1 is discharged, thereby controlling the pressure difference between the first oil passage S1 and the second oil passage S2. Also, for example, the OCV 50 is in the initial state when the drive unit is not energized. In addition, the OCV 50 constitutes a pressure control unit in the first embodiment. In addition, the first oil passage and the second oil passage constitute a first flow path and a second flow path in the first embodiment.

Next, referring to Figures 2 and 3, the valve timing adjustment device 100A according to the first embodiment will be described in detail. Figure 2A is a front view showing the valve timing adjustment device 100A according to the first embodiment in a state where hydraulic pressure is not being transmitted, Figure 2B is a front view showing the internal structure in a state where hydraulic pressure is not being transmitted, and Figure 3 is a cross-sectional view showing the valve timing adjustment device 100A according to the first embodiment in a cross-sectional view taken along line A-A in Figure 2B. For ease of viewing, Figures 2A, 2B, and 3 are views in a state where the OCV 50 has been removed, and Figure 2B is a view in a state where components unnecessary for the description, such as the first plate 13 described later, have been removed. Also, Figure 3 is a view in a state where the first plate 13 has been attached.

The housing 10 has the above-mentioned sprocket part 11, case 12, first plate 13, second plate 14 and bush 15. The sprocket part 11 is formed in a cylindrical shape centered on the rotation axis L1, has a plurality of teeth arranged on the outside that mesh with the roller chain, and forms a space inside to accommodate the case 12.

The case 12 has a cylindrical case cylindrical portion 120 and a first shoe 121, a second shoe 122, a third shoe 123, and a fourth shoe 124 formed to protrude radially inward from the inner surface of the case cylindrical portion 120, and rotates integrally with the sprocket portion 11 around the rotation axis L1. The first shoe 121 to the fourth shoe 124 are arranged at different circumferential positions on the inner surface of the case cylindrical portion 120 with gaps between them.

The first plate 13 and the second plate 14 are arranged with a gap between them in the direction of the rotation axis L1, so as to close both ends of the case 12 in the direction of the rotation axis L1. As a result, the case 12, the first plate 13, and the second plate 14 form a space S0 inside. The first plate 13 has a first spring holding portion 131 that holds one end 311 of the spiral spring 31, and a second spring holding portion 132 that holds the other end 312 of the spiral spring 31.

The bushing 15 is held by the first plate 13 and engages with the lock pin 32, which is positioned in the limiting position, to limit the rotation of the rotor 20 relative to the housing 10. When the lock pin 32 is positioned in the permissible position, it is disengaged from the bushing 15.

The rotor 20 has a rotor body 21 arranged in the space S0, a holder 22 that can contact the other end 312 of the spiral spring 31 in the rotational direction of the rotor 20, a first check valve 25 and a second check valve 26, a pair of valve guides 24, 24 that guide the movement of the first check valve 25 and the second check valve 26, and a pair of valve springs 27, 27 that bias the first check valve 25 and the second check valve 26.

The rotor body 21 has a rotor cylindrical portion 210 formed in a cylindrical shape centered on the rotation axis L1, and a first vane 211, a second vane 212, a third vane 213, and a fourth vane 214 formed to protrude radially outward from the outer surface of the rotor cylindrical portion 210. The first vane 211 to the fourth vane 214 are arranged at different positions on the circumference of the outer surface of the rotor cylindrical portion 210 with gaps between them. Specifically, the first vane 211 is arranged between the first shoe 121 and the second shoe 122 of the case 12, the second vane 212 is arranged between the second shoe 122 and the third shoe 123 of the case 12, the third vane 213 is arranged between the third shoe 123 and the fourth shoe 124 of the case 12, and the fourth vane 214 is arranged between the fourth shoe 124 of the case 12 and the first shoe 121. In the first embodiment, the first vane 211 to the fourth vane 214 form a partition portion.

The first vane 211 also forms a lock pin release chamber S5 therein, which is a space capable of accommodating the lock pin 32, the lock pin spring 33, the first check valve 25, the second check valve 26, the valve guides 24, 24, and the valve springs 27, 27. In other words, the lock pin 32, the lock pin spring 33, the first check valve 25, the second check valve 26, the valve guides 24, 24, and the valve springs 27, 27 are provided inside the first vane 211. In the first embodiment, the first check valve 25 constitutes the first valve, and the second check valve 26 constitutes the second valve. In the first embodiment, the lock pin release chamber S5 constitutes the third space.

One valve guide 24 is held in the lock pin release chamber S5 and supports the first check valve 25 so that it can move along the rotation axis L1. One valve spring 27 urges the first check valve 25 in one direction along the rotation axis L1 so that the first check valve 25 moves relative to the one valve guide 24. The other valve guide 24 is held in the lock pin release chamber S5 and supports the second check valve 26 so that it can move along the rotation axis L1. The other valve spring 27 urges the second check valve 26 in one direction along the rotation axis L1 so that the second check valve 26 moves relative to the other valve guide 24. The valve guides 24, 24 suppress the sliding resistance when the first check valve 25 and the second check valve 26 move, improving the stability of the operation of the first check valve 25 and the second check valve 26.

Thus configured, the lock pin 32, lock pin spring 33, first check valve 25, second check valve 26, valve guides 24, 24, and valve springs 27, 27 are supported by the first vane 211 so as to rotate integrally with the rotor 20 relative to the housing 10 when the lock pin 32 is in the permitted position. The operation of the lock pin 32, the first check valve, and the second check valve 26 will be described in detail later.

The holder 22 has a lever 221 that can contact the other end 312 of the spiral spring 31 in the rotation direction of the rotor 20, and rotates integrally with the rotor body 21 relative to the housing 10. When the rotation position of the rotor 20 relative to the housing 10 is within a predetermined range, the lever 221 contacts the other end 312 of the spiral spring 31 in the rotation direction of the rotor 20 and receives a biasing force from the spiral spring 31, and is configured not to contact the other end 312 of the spiral spring 31 when the rotation position of the rotor 20 relative to the housing 10 is outside the above-mentioned predetermined range. The biasing force that the lever 221 receives from the spiral spring 31 will be described in detail later.

Next, the operation of the rotor 20 according to the first embodiment will be described with reference to Figures 2 and 3. The rotor 20 is supported to be rotatable around the rotation axis L1 within a predetermined angle range with respect to the housing 10 between an advance angle position where the first vane 211 contacts the second shoe 122 in the rotation direction of the rotor 20 and a retard angle position where the first vane 211 contacts the first shoe 121 in the rotation direction of the rotor 20. In other words, the rotor 20 is supported to be rotatable in the rotation direction R1 and the rotation direction R2 within a predetermined angle range with respect to the housing 10 between an advance angle position where the first vane 211 contacts the second shoe 122 in the rotation direction R1 and a retard angle position where the first vane 211 contacts the first shoe 121 in the rotation direction R2. In addition, in FIG. 2A and FIG. 2B, the rotation direction R1 is a clockwise direction around the rotation axis L1, and the rotation direction R2 is a counterclockwise direction around the rotation axis L1.

In the following, the rotation direction R1 is also referred to as the advance angle direction R1, and the rotation direction R2 is also referred to as the retard angle direction R2. Figures 2A and 2B show a state in which the rotor 20 is located at an intermediate position between the advance angle position and the retard angle position relative to the housing 10. In embodiment 1, the intermediate position is a position in the middle between the advance angle position and the retard angle position. In addition, the advance angle position constitutes the first position in embodiment 1, the retard angle position constitutes the second position in embodiment 1, and the intermediate position constitutes the third position in embodiment 1.

In addition, the rotor 20 is not limited to being supported so as to be rotatable between an advance angle position where the first vane 211 contacts the second shoe 122 and a retarded angle position where the first vane 211 contacts the first shoe 121, but may be supported so as to be rotatable between an advance angle position where the second vane 212 contacts the third shoe 123 in the rotation direction of the rotor 20 and a retarded angle position where the second vane 212 contacts the second shoe 122 in the rotation direction of the rotor 20, or may be supported so as to be rotatable between an advance angle position where the second vane 212 contacts the third shoe 123 in the rotation direction of the rotor 20 and a retarded angle position where the second vane 212 contacts the second shoe 122 in the rotation direction of the rotor 20. The third vane 213 may be supported rotatably between an advance position where the fourth shoe 124 contacts the fourth shoe 124 in the rotational direction of the rotor 20 and a retarded position where the third vane 213 contacts the third shoe 123 in the rotational direction of the rotor 20, or the fourth vane 214 may be supported rotatably between an advance position where the first shoe 121 contacts the rotor 20 in the rotational direction and a retarded position where the fourth vane 214 contacts the fourth shoe 124 in the rotational direction of the rotor 20.

When the rotor 20 is in the advanced position (see FIG. 6B), the rotational force of the housing 10 is transmitted to the camshaft 2 (see FIG. 1) so that the timing of opening and closing the valves of the internal combustion engine is earlier than when the rotor 20 is in the intermediate position. When the rotor 20 is in the retarded position (see FIG. 8B), the rotational force of the housing 10 is transmitted to the camshaft 2 (see FIG. 1) so that the timing of opening and closing the valves of the internal combustion engine is later than when the rotor 20 is in the intermediate position. In this way, the valve timing adjustment device 100A is configured to be able to adjust the timing of opening and closing the valves of the internal combustion engine by changing the rotational position of the rotor 20 relative to the housing 10 using hydraulic pressure transmitted from the OCV 50 (see FIG. 1).

The outer surface of the rotor cylindrical portion 210 is close to or in contact with the tips of the first shoe 121 to fourth shoe 124 of the case 12 in the radial direction of the rotor 20, and the tips of the first vane 211 to fourth vane 214 are close to or in contact with the inner surface of the case cylindrical portion 120 of the case 12 in the radial direction of the rotor 20. In addition, both ends of the rotor body 21 in the direction of the rotation axis L1 are close to or in contact with the inner surface (S0 side surface) of the first plate 13 and the inner surface (S0 side surface) of the second plate 14.

By being arranged in this manner, when the rotor 20 is in the intermediate position, an advance hydraulic chamber S3 is formed, which is a space partitioned by the first shoe 121, the case cylindrical portion 120, the first vane 211, the rotor cylindrical portion 210, the first plate 13, and the second plate 14. Also, when the rotor 20 is in the intermediate position, a retard hydraulic chamber S4 is formed, which is a space partitioned by the second shoe 122, the case cylindrical portion 120, the first vane 211, the rotor cylindrical portion 210, the first plate 13, and the second plate 14.

In addition, when the rotor 20 is positioned at the intermediate position, an advance hydraulic chamber S3 is formed, which is a space partitioned by the second shoe 122, the case cylindrical portion 120, the second vane 212, the rotor cylindrical portion 210, the first plate 13, and the second plate 14. In addition, when the rotor 20 is positioned at the intermediate position, a retard hydraulic chamber S4 is formed, which is a space partitioned by the third shoe 123, the case cylindrical portion 120, the second vane 212, the rotor cylindrical portion 210, the first plate 13, and the second plate 14.

In addition, when the rotor 20 is positioned at the intermediate position, an advance hydraulic chamber S3 is formed, which is a space partitioned by the third shoe 123, the case cylindrical portion 120, the third vane 213, the rotor cylindrical portion 210, the first plate 13, and the second plate 14. In addition, when the rotor 20 is positioned at the intermediate position, a retard hydraulic chamber S4 is formed, which is a space partitioned by the fourth shoe 124, the case cylindrical portion 120, the third vane 213, the rotor cylindrical portion 210, the first plate 13, and the second plate 14.

In addition, when the rotor 20 is in the intermediate position, an advance hydraulic chamber S3 is formed, which is a space partitioned by the fourth shoe 124, the case cylindrical portion 120, the fourth vane 214, the rotor cylindrical portion 210, the first plate 13, and the second plate 14. In addition, when the rotor 20 is in the intermediate position, a retard hydraulic chamber S4 is formed, which is a space partitioned by the first shoe 121, the case cylindrical portion 120, the fourth vane 214, the rotor cylindrical portion 210, the first plate 13, and the second plate 14. In addition, in the first embodiment, the advance hydraulic chamber S3 constitutes the first space, and the retard hydraulic chamber S4 constitutes the second space.

Each advance hydraulic chamber S3 communicates with the first oil passage S1, and the hydraulic pressure generated in the first oil passage S1 is transmitted thereto. Each retard hydraulic chamber S4 communicates with the second oil passage S2, and the hydraulic pressure generated in the second oil passage S2 is transmitted thereto. The rotor 20 receives torque to rotate in the advance direction R1 due to the hydraulic pressure transmitted to the advance hydraulic chamber S3. The rotor 20 receives torque to rotate in the retard direction R2 due to the hydraulic pressure transmitted to the retard hydraulic chamber S4. Therefore, when the lock pin 32 is in the allowable position, the rotor 20 rotates relative to the housing 10 between the advance position and the retard position due to the pressure difference between the hydraulic pressure transmitted to each advance hydraulic chamber S3 and the hydraulic pressure transmitted to each retard hydraulic chamber S4. In other words, when the lock pin 32 is positioned in the permissible position, the rotor 20 rotates relative to the housing 10 between the advance position and the retard position due to the pressure difference between the oil pressure transmitted to the first oil passage S1 and the oil pressure transmitted to the second oil passage S2.

For example, when the rotor 20 is in an intermediate position or a retarded position relative to the housing 10 and the lock pin 32 is in the allowable position, if a predetermined hydraulic pressure is transmitted to each advance hydraulic chamber S3 and the hydraulic oil in each retard hydraulic chamber S4 is drained, the rotor 20 rotates in the advance direction R1 until it is in the advanced position. Also, when the rotor 20 is in an intermediate position or a retarded position relative to the housing 10 and the lock pin 32 is in the allowable position, if a predetermined hydraulic pressure is transmitted to each retard hydraulic chamber S4 and the hydraulic oil in each advance hydraulic chamber S3 is drained, the rotor 20 rotates in the retard direction R2 until it is in the retarded position.

In addition, the rotor 20 receives torque (cam torque) from the camshaft 2 while transmitting the rotational force of the housing 10 to the camshaft 2. The cam torque is composed of frictional resistance when rotating the camshaft 2, forces when opening and closing a valve (not shown) of the internal combustion engine, etc., and changes depending on the rotation phase of the camshaft 2, the rotation speed of the camshaft 2, the temperature of the internal combustion engine, etc. In general, the rotor 20 receives cam torque in the advance direction R1 and cam torque in the retard direction R2 alternately, but the direction of the average cam torque, which is the time average value of the cam torque received by the rotor 20, is the direction of the torque received by the rotor 20 from the housing 10, that is, the retard direction R2, which is the opposite direction to the advance direction R1. In such a case, the direction of the maximum cam torque, which is the maximum value of the cam torque received by the rotor 20 during one rotation of the camshaft, is the retard direction R2.

When the rotational position of the rotor 20 relative to the housing 10 is within the range from the intermediate position to the retarded position, the other end 312 of the spiral spring 31 and the lever 221 come into contact in the rotational direction of the rotor 20 and receive a biasing force from the spiral spring 31. When the rotational position of the rotor 20 relative to the housing 10 is within the range from the intermediate position to the retarded position, the rotor 20 receives a biasing force from the spiral spring 31 to rotate in the advance direction R1, which is the opposite direction to the rotational direction caused by the average cam torque and the maximum cam torque. For example, when the rotational position of the rotor 20 is within the range from the retarded position to the intermediate position, the spiral spring 31 applies a torque to the rotor 20 in the opposite direction to the average cam torque and greater than the average cam torque.

In this way, the rotor 20 according to the first embodiment rotates toward the intermediate position by the reaction force of the spiral spring 31 within the range from the intermediate position to the retarded position, and rotates toward the intermediate position by the cam torque within the range from the intermediate position to the advanced position, so that the rotation position is held between the advanced position and the retarded position when the lock pin 32 is in the allowable position and there is no pressure difference between the first oil passage S1 and the second oil passage S2. For example, the rotor 20 is held in a rotation position so as to be located approximately in the intermediate position when the lock pin 32 is in the allowable position and there is no pressure difference between the first oil passage S1 and the second oil passage S2. Specifically, the rotor 20 is held in a rotation position so as to be located within ±1° of the intermediate position when the lock pin 32 is in the allowable position and there is no pressure difference between the first oil passage S1 and the second oil passage S2.

Next, the operation of the lock pin 32 according to the first embodiment will be described with reference to Figures 2 and 3. The lock pin release chamber S5 described above is formed to be capable of transmitting hydraulic pressure from the advance hydraulic chamber S3 and the retard hydraulic chamber S4. In other words, the lock pin release chamber S5 is formed to be capable of communicating with the advance hydraulic chamber S3 and the retard hydraulic chamber S4. In other words, the lock pin release chamber S5 is formed to be capable of communicating with the first oil passage S1 and the second oil passage S2. Specifically, the lock pin release chamber S5 is disposed between the advance hydraulic chamber S3 and the retard hydraulic chamber S4, and is formed to be capable of communicating with the first oil passage S1, the second oil passage S2, the advance hydraulic chamber S3, and the retard hydraulic chamber S4.

The first check valve 25 is disposed between the advance hydraulic chamber S3 and the lock pin release chamber S5, and switches between a state in which hydraulic pressure is permitted to be transmitted between the advance hydraulic chamber S3 and the lock pin release chamber S5 (open state) and a state in which hydraulic pressure is restricted between the advance hydraulic chamber S3 and the lock pin release chamber S5 (closed state). The second check valve 26 is disposed between the retard hydraulic chamber S4 and the lock pin release chamber S5, and switches between a state in which hydraulic pressure is permitted to be transmitted between the retard hydraulic chamber S4 and the lock pin release chamber S5 (open state) and a state in which hydraulic pressure is restricted between the retard hydraulic chamber S4 and the lock pin release chamber S5 (closed state). Figure 3 shows a state in which the first check valve 25 and the second check valve 26 are both closed. The first check valve 25 prevents hydraulic oil from flowing out from the retard hydraulic chamber S4 to the advance hydraulic chamber S3 when the hydraulic pressure in the retard hydraulic chamber S4 is higher than that in the advance hydraulic chamber S3, thereby improving the rotation speed of the rotor 20 in the retard direction R2. The second check valve 26 prevents hydraulic oil from flowing out from the advance hydraulic chamber S3 to the retard hydraulic chamber S4 when the hydraulic pressure in the advance hydraulic chamber S3 is higher than that in the retard hydraulic chamber S4, thereby improving the rotation speed of the rotor 20 in the advance direction R1.

One valve spring 27 biases the first check valve 25 from an open position to a closed position. Similarly, the other valve spring 27 biases the second check valve 26 from an open position to a closed position. The valve springs 27, 27 bias the first check valve 25 and the second check valve 26 so that when hydraulic pressure is not transmitted to the first oil passage S1 and the second oil passage S2, the first check valve 25 and the second check valve 26 are both configured to maintain a closed state. When the hydraulic pressure transmitted to the first oil passage S1 exceeds a predetermined value in the closed state, the first check valve 25 moves against the reaction force of the valve spring 27 to open. When the hydraulic pressure transmitted to the second oil passage S2 exceeds a predetermined value in the closed state, the second check valve 26 moves against the reaction force of the valve spring 27 to open.

The lock pin 32 is arranged so that the surface intersecting the rotation axis L1 is exposed to the lock pin release chamber S5. By being arranged in this manner, the lock pin 32 moves between the restricted position and the allowable position along the rotation axis L1 due to changes in the hydraulic pressure in the lock pin release chamber S5. For example, when the lock pin 32 is in the restricted position and the hydraulic pressure transmitted to the lock pin release chamber S5 exceeds a predetermined value, the lock pin 32 moves from the restricted position to the allowable position by the hydraulic pressure transmitted to the lock pin release chamber S5. Specifically, when the lock pin 32 is in the restricted position and the magnitude of the force that presses the lock pin 32 from the restricted position to the allowable position by the hydraulic pressure transmitted to the lock pin release chamber S5 exceeds the magnitude of the resultant force of the frictional force when the lock pin 32 moves and the reaction force of the lock pin spring 33, the lock pin 32 moves from the restricted position to the allowable position by the hydraulic pressure transmitted to the lock pin release chamber S5.

In this way, the valve timing adjustment device 100A according to the first embodiment maintains the lock pin 32 in the allowable position while hydraulic pressure is transmitted to at least one of the first oil passage S1 and the second oil passage S2, and prevents the lock pin 32 from getting caught in the bush 15 when the rotor 20 is rotated relative to the housing 10 by the hydraulic pressure difference between the first oil passage S1 and the second oil passage S2. It is preferable that the reaction force of the valve spring 27 and the reaction force of the lock pin spring 33 are each set so that the hydraulic pressure required to move the first check valve 25 and the second check valve 26 from the closed state to the open state is smaller than the hydraulic pressure required to move the lock pin 32 from the restricted position to the allowable position. By setting them in this way, it is possible to manage the hydraulic pressure required to move the lock pin 32 based on the reaction force of the lock pin spring 33.

Next, the overall operation of the valve timing adjustment device 100A according to the first embodiment will be described with reference to Figures 2 to 9. As described above, Figures 2A, 2B, and 3 show a state in which hydraulic pressure is not transmitted to the first oil passage S1 and the second oil passage S2. In this state, the rotor 20 is in the intermediate position, the lock pin 32 is in the limiting position, and the first check valve 25 and the second check valve 26 are in the closed state. In a state in which the internal combustion engine is stopped and hydraulic pressure is not being generated by the oil pump and in a state in which the input of hydraulic pressure is blocked by the OCV 50, each component of the valve timing adjustment device 100A is in the position shown in Figures 2A, 2B, and 3.

2A, 2B, and 3, when the internal combustion engine starts to rotate the crankshaft, a cam torque acts on the rotor 20 in a direction that rotates the rotor 20 in the advance angle direction R1 and the retard angle direction R2 relative to the housing 10, but the lock pin 32, which is in the limit position, is engaged with the bush 15, so the rotor 20 maintains its state in the intermediate position. At this time, if the clearance between the lock pin 32 and the bush 15 in the advance angle direction R1 and the retard angle direction R2 is small, the generation of contact noise between the lock pin 32 and the bush 15 can be suppressed.

When the crankshaft rotates further and the oil passages from the oil pump to the first oil passage S1 and the second oil passage S2 are connected, the oil pressure from the oil pump increases and sufficient oil pressure is transmitted to the first oil passage S1 and the second oil passage S2. The lock pin 32 moves from the restricting position to the allowing position while contacting the bush 15 in the advance direction R1 and the retard direction R2, and the valve timing adjustment device 100A reaches the state shown in Figures 4A, 4B, and 5.

Figure 4A is a front view showing the valve timing adjustment device 100A according to the first embodiment in a state where hydraulic pressure is transmitted to the first oil passage S1 and the second oil passage S2, and Figure 4B is a front view showing the internal structure of the valve timing adjustment device 100A according to the first embodiment in a state where hydraulic pressure is transmitted to the first oil passage S1 and the second oil passage S2, and Figure 5 is a cross-sectional view showing the valve timing adjustment device 100A according to the first embodiment in a cross-sectional view taken along the line A-A in Figure 4B. In this state, the rotor 20 is maintained in an approximately intermediate position by the reaction force of the spiral spring 31 and the cam torque, the lock pin 32 has moved from the limit position in the direction B to the allowable position, and the first check valve 25 and the second check valve 26 have moved from the closed state to the direction C to the open state. In this state, the first oil passage S1, the second oil passage S2, the advance hydraulic chamber S3, the retard hydraulic chamber S4, and the lock pin release chamber S5 are in communication with each other.

When the oil pressure transmitted to the first oil passage S1 becomes higher than the oil pressure transmitted to the second oil passage S2 by operating the OCV 50 in the states shown in Figures 4A, 4B, and 5, the valve timing adjustment device 100A goes into the states shown in Figures 6A, 6B, and 7. Figure 6A is a diagram showing the valve timing adjustment device 100A according to the first embodiment, and is a front view showing the appearance in a state where oil pressure is transmitted to the first oil passage S1, and Figure 6B is a diagram showing the valve timing adjustment device 100A according to the first embodiment, and is a front view showing the internal structure in a state where oil pressure is transmitted to the first oil passage S1. Figure 7 is a cross-sectional view showing the valve timing adjustment device 100A according to the first embodiment, and is a cross-sectional view taken along the line A-A in Figure 6B.

6A, 6B and 7 show a state in which sufficient oil pressure is transmitted from the oil pump to the first oil passage S1, and the hydraulic oil in the second oil passage S2 is discharged and the oil pressure in the second oil passage S2 is zero, i.e., no oil pressure is transmitted from the oil pump to the second oil passage S2. In this state, the rotor 20 rotates in the advance direction R1 relative to the housing 10 against the cam torque due to the oil pressure in the advance hydraulic chamber S3, the lock pin 32 maintains its allowable position, the first check valve 25 maintains its open state, and the second check valve 26 changes from its open state to its closed state.

When the OCV 50 operates in the states shown in Figures 4A, 4B, and 5, and the oil pressure transmitted to the second oil passage S2 becomes higher than the oil pressure transmitted to the first oil passage S1, the valve timing adjustment device 100A goes into the states shown in Figures 8A, 8B, and 9. Figure 8A is a diagram showing the valve timing adjustment device 100A according to the first embodiment, and is a front view showing the appearance in a state where oil pressure is transmitted to the second oil passage S2, and Figure 8B is a diagram showing the valve timing adjustment device 100A according to the first embodiment, and is a front view showing the internal structure in a state where oil pressure is transmitted to the second oil passage S2. Figure 9 is a cross-sectional view showing the valve timing adjustment device 100A according to the first embodiment, and is a cross-sectional view taken along line A-A in Figure 8B.

8A, 8B and 9 show a state in which sufficient oil pressure is transmitted from the oil pump to the second oil passage S2, and the hydraulic oil in the first oil passage S1 is discharged and the oil pressure in the first oil passage S1 is zero, i.e., a state in which no oil pressure is transmitted from the oil pump to the first oil passage S1. In this state, the rotor 20 rotates in the retard direction R2 relative to the housing 10 against the reaction force of the spiral spring 31 due to the oil pressure in the retard hydraulic chamber S4, the lock pin 32 maintains its allowable position, the first check valve 25 changes from an open state to a closed state, and the second check valve 26 maintains its open state.

When the internal combustion engine is stopped and adjustment of the valve opening/closing timing is completed in the state shown in Figures 6 to 9, the valve timing adjustment device 100A first goes to the initial state with the OCV 50, oil pressure is transmitted to both the first oil passage S1 and the second oil passage S2, there is no oil pressure difference between the advance hydraulic chamber S3 and the retard hydraulic chamber S4, and the rotor 20 is positioned approximately in the middle position due to the reaction force of the spiral spring 31 and the cam torque, as shown in Figures 4 and 5.

After that, when the rotation speed of the crankshaft gradually decreases and the oil pressure from the oil pump decreases, the valve timing adjustment device 100A enters the state shown in Figures 2A, 2B and 3, in which the lock pin 32 and the bush 15 are engaged with each other with the rotor 20 in the intermediate position, restricting the rotation of the rotor 20 relative to the housing 10. In this way, the valve timing adjustment device 100A according to embodiment 1 enters a state in which the lock pin 32 is in the restricting position with the internal combustion engine stopped.

As described above, the valve timing adjustment device 100A according to the first embodiment is configured to move the lock pin 32 by a change in pressure in the lock pin release chamber S5 to which hydraulic pressure for rotating the rotor 20 relative to the housing 10 is transmitted. Therefore, the structure of the housing 10, the rotor 20, and the OCV 50 can be simplified compared to a case in which the oil passage for moving the lock pin 32 and the oil passage for rotating the rotor 20 are formed independently of each other. In addition, the valve timing adjustment device 100A according to the first embodiment can be made smaller than the conventional device due to the simplified structure. Furthermore, by making it possible to make the device smaller, it is possible to increase the range of angles at which the rotor 20 can rotate relative to the housing 10, and it is possible to expand the adjustment range of the opening and closing timing of the valves of the internal combustion engine compared to the conventional device.

In addition, in the valve timing adjustment device 100A according to the first embodiment, when the lock pin 32 is in the allowable position, the rotor 20 is held at approximately the middle position by the reaction force of the spiral spring 31, so that when the internal combustion engine is operating and oil pressure is generated in the oil pump, the lock pin 32 can be maintained in the allowable position. This eliminates the need to form an oil passage for moving the lock pin 32 and an oil passage for rotating the rotor 20 independently of each other, and simplifies the structure. In addition, by configuring in this way, even if the start and end of the adjustment of the opening and closing timing of the valve are performed multiple times, the movement of the lock pin 32 can be limited to only when the internal combustion engine starts and ends its operation, so that it is possible to suppress the lock pin 32 from getting caught in the bush 15 when the lock pin 32 is moved.

In addition, in the valve timing adjustment device 100A according to the first embodiment, the lock pin 32, the lock pin spring 33, the first check valve 25, the second check valve 26, the valve guides 24, 24, and the valve springs 27, 27 are provided inside the first vane 211. The first vane 211 is the part of the first vane 211 to the fourth vane 214 that comes into contact with the housing 10 in the rotation direction when the rotor 20 rotates relative to the housing 10, and is formed to have the largest outer diameter of the first vane 211 to the fourth vane 214. By providing the above-mentioned lock pin 32, lock pin spring 33, first check valve 25, second check valve 26, valve guides 24, 24, and valve springs 27, 27 in this manner to the first vane 211, the valve timing adjustment device 100A can be made more compact than if they were provided in other parts, such as the rotor cylindrical portion 210, the second vane 212 to the fourth vane 214, etc.

In addition, the valve timing adjustment device 100A according to the first embodiment is configured such that the lock pin 32, the first check valve 25, and the second check valve 26 are provided on the first vane 211 and move in the same direction as the rotation axis L1. As a result, the valve timing adjustment device 100A can reduce the size of the first vane 211 when viewed from the direction of the rotation axis L1, and can increase the range of angles over which the rotor 20 can rotate relative to the housing 10, compared to a case in which the lock pin 32, the first check valve 25, and the second check valve 26 move in different directions.

In the first embodiment, the valve timing adjustment device 100A is configured so that the rotor 20, the lock pin 32, the first check valve 25, and the second check valve 26 move due to the pressure of the hydraulic oil, but is not limited to this. The valve timing adjustment device may be configured so that the rotor, the lock pin, the first check valve, and the second check valve move due to the pressure of the hydraulic fluid, and the hydraulic fluid may be a fluid other than hydraulic oil.

In addition, in the first embodiment, the first check valve 25 and the second check valve 26 are biased by the valve spring 27 in the direction toward the closed state, but this is not limited thereto. The first check valve may be configured to switch between a state in which the pressure of the working fluid is permitted to be transmitted between the advance hydraulic chamber and the lock pin release chamber and a state in which the pressure of the working fluid is restricted between the advance hydraulic chamber and the lock pin release chamber, and may be configured to switch between these states by the pressure difference of the working fluid between the first oil passage and the second oil passage, without relying on the reaction force of the spring, for example. Similarly, the second check valve may be configured to switch between a state in which the pressure of the working fluid is permitted to be transmitted between the retard hydraulic chamber and the lock pin release chamber and a state in which the pressure of the working fluid is restricted between the retard hydraulic chamber and the lock pin release chamber, and may be configured to switch between these states by the pressure difference of the working fluid between the first oil passage and the second oil passage, without relying on the reaction force of the spring, for example. Furthermore, since the valve timing adjusting device has the valve spring, it is possible to stabilize the valve opening hydraulic pressure of the first check valve and the second check valve.

In addition, in the first embodiment, the valve timing adjustment device 100A has the lock pin 32, the lock pin spring 33, the first check valve 25, the second check valve 26, the valve guides 24, 24, and the valve springs 27, 27 provided inside the first vane 211, but is not limited thereto. In the valve timing adjustment device, any one or more of the components of the lock pin, the lock pin spring, the first check valve, the second check valve, the valve guide, and the valve spring may be provided inside the first vane, or a part of any one or more of these components may be provided inside the first vane. In addition, the lock pin may be arranged so that the entirety is housed inside the first vane when it is located in the allowable position, or may be arranged so that a part is housed inside the first vane, but by arranging the entirety to be housed inside the first vane when it is located in the allowable position, it is possible to suppress the lock pin from getting caught in the bush when the rotor rotates. The lock pin may also be configured to be held by the housing and rotate integrally with the housing.

In addition, in the first embodiment, the valve timing adjustment device 100A is configured so that the movement direction of the lock pin 32, the first check valve 25, and the second check valve 26 is the direction of the rotation axis L1, but is not limited to this. The valve timing adjustment device may be configured so that the lock pin can move between the limit position and the allowable position by the hydraulic pressure transmitted to the lock pin release chamber, for example, the valve timing adjustment device may be configured so that the lock pin moves along the radial direction of the rotor. In addition, the valve timing adjustment device may be configured so that the first check valve opens and closes the flow path of the working fluid between the advance hydraulic chamber and the lock pin release chamber, and the second check valve opens and closes the flow path of the working fluid between the retard hydraulic chamber and the lock pin release chamber, for example, the first check valve and the second check valve may be configured to move along a direction intersecting the rotation axis L1 and the radial direction of the rotor.

Embodiment 2.
Next, a valve timing adjusting device 100B according to a second embodiment will be described with reference to Figures 10 to 18. The valve timing adjusting device 100B according to the second embodiment differs from the valve timing adjusting device 100A according to the first embodiment in the configuration for switching between a state in which transmission of hydraulic pressure is permitted and a state in which transmission of hydraulic pressure is restricted between the advance hydraulic chamber S3, the retard hydraulic chamber S4, and the lock pin release chamber S5, but other configurations are similar, and the same reference numerals are used to designate the same configuration as in the first embodiment, and description thereof will be omitted.

Figure 10A is a diagram showing a valve timing adjustment device 100B according to embodiment 2, and is a front view showing the appearance when hydraulic pressure is not being transmitted; Figure 10B is a diagram showing the valve timing adjustment device 100B according to embodiment 2, and is a front view showing the internal structure when hydraulic pressure is not being transmitted; Figure 11 is an enlarged view of the valve timing adjustment device 100B according to embodiment 2, and is an enlarged view of D in Figure 10B; and Figure 12 is a cross-sectional view of the valve timing adjustment device 100B according to embodiment 2, and is a cross-sectional view taken along line H-H in Figure 10B.

The rotor 20B of the valve timing adjustment device 100B according to the second embodiment has a rotor body 21B arranged in the space S0, a holder 22, a first check valve 25B and a second check valve 26B, and a pair of valve springs 27B, 27B that bias the first check valve 25B and the second check valve 26B. The rotor 20 body 21B also has a first vane 211B, a second vane 212, a third vane 213, and a fourth vane 214. The first vane 211B has a spring holding portion 24B that holds the valve springs 27B, 27B. In the second embodiment, the rotor 20B, the first vane 211B, the first check valve 25B, and the second check valve 26B respectively constitute a second rotating body, a partition portion, a first valve, and a second valve.

A gap is formed between the first vane 211B and the housing 10. The first check valve 25B and the second check valve 26B are arranged between the inner surface of the housing 10 and the first vane 211B in the radial direction of the rotation of the rotor 20B relative to the housing 10. The first check valve 25B is exposed to the advance hydraulic chamber S3, and the second check valve 26B is exposed to the retard hydraulic chamber S3. The spring retaining portion 24B is arranged between the first check valve 25B and the second check valve 26B in the rotation direction of the rotor 20B. In addition, the spring retaining portion 24B is recessed in the direction of the rotation axis L1 more than other parts of the first vane 211, and forms a lock pin release chamber S5 between the first plate 13. In addition, the first check valve 25B and the second check valve 26B are movable in a direction intersecting the direction of the rotation axis L1 and the radial direction, for example, along the circumferential direction of the rotor 20B, and by moving in that direction, they open and close the gap formed by the inner surface of the housing 10 and the first vane 211B.

Specifically, the first check valve 25B moves along the direction intersecting the direction of the rotation axis L1 and the radial direction to switch between an open state that allows hydraulic pressure to be transmitted between the advance hydraulic chamber S3 and the lock pin release chamber S5 and a closed state that restricts hydraulic pressure transmission between the advance hydraulic chamber S3 and the lock pin release chamber S5. The second check valve 26B moves along the direction intersecting the direction of the rotation axis L1 and the radial direction to switch between an open state that allows hydraulic pressure to be transmitted between the retard hydraulic chamber S4 and the lock pin release chamber S5 and a closed state that restricts hydraulic pressure transmission between the retard hydraulic chamber S4 and the lock pin release chamber S5. One valve spring 27B is disposed between the first check valve 25B and the spring holding portion 24B, and biases the first check valve 25B from the position where the first check valve 25B is in the open state toward the position where the first check valve 25B is in the closed state. The other valve spring 27B is disposed between the second check valve 26B and the spring retaining portion 24B, and biases the second check valve 26B from an open position toward a closed position.

11 is a diagram showing a state in which the first check valve 25B and the second check valve 26B are both in a closed state. The lock pin release chamber S5 according to the second embodiment communicates with a gap formed by the inner surface of the housing 10 and the first vane 211B, and when at least one of the first check valve 25B and the second check valve 26B is in an open state, the oil pressure transmitted to the lock pin release chamber S5 moves the lock pin 32 from the restricting position to the allowing position.

Figure 13A is a diagram showing a valve timing adjustment device 100B according to embodiment 2, and is a front view showing the external appearance when hydraulic pressure is transmitted to the first oil passage S1 and the second oil passage S2; Figure 13B is a diagram showing a valve timing adjustment device 100B according to embodiment 2, and is a front view showing the internal structure when hydraulic pressure is transmitted to the first oil passage S1 and the second oil passage S2; Figure 14 is an enlarged view of the valve timing adjustment device 100B according to embodiment 2, and is an enlarged view of D in Figure 13B.

When hydraulic pressure is transmitted to the first oil passage S1 and the second oil passage S2, the hydraulic pressure in the advance hydraulic chamber S3 pushes the first check valve 25B in the E direction, moving it from a closed state to an open state, and the hydraulic pressure in the retard hydraulic chamber S4 pushes the second check valve 26B in the F direction, moving it from a closed state to an open state, resulting in the state shown in Figures 13A, 13B, and 14. In this state, hydraulic pressure from the advance hydraulic chamber S3 and the retard hydraulic chamber S4 is transmitted in the G direction, and the lock pin 32 moves from the restricted position to the permitted position. In this state, the advance hydraulic chamber S3, the retard hydraulic chamber S4, and the lock pin release chamber S5 are also in communication with each other.

Figure 15A is a diagram showing a valve timing adjustment device 100B according to embodiment 2 and is a front view showing the appearance when hydraulic pressure is transmitted to the first oil passage S1, Figure 15B is a diagram showing a valve timing adjustment device 100B according to embodiment 2 and is a front view showing the internal structure when hydraulic pressure is transmitted to the first oil passage S1, and Figure 16 is an enlarged view of the valve timing adjustment device 100B according to embodiment 2 and is an enlarged view of D in Figure 15B.

When hydraulic pressure is transmitted to the first oil passage S1 and not to the second oil passage S2, the hydraulic pressure in the advance hydraulic chamber S3 pushes the first check valve 25B in the E direction to an open state, and the hydraulic pressure in the advance hydraulic chamber S3 pushes the second check valve 26B to a closed state, resulting in the state shown in Figures 15A, 15B, and 16. In this state, hydraulic pressure from the advance hydraulic chamber S3 is transmitted in the G direction, and the lock pin 32 moves from the restricted position to the permitted position. In this state, the advance hydraulic chamber S3 and the lock pin release chamber S5 are also in communication with each other.

Figure 17A is a diagram showing a valve timing adjustment device 100B according to embodiment 2 and is a front view showing the external appearance when hydraulic pressure is transmitted to the second oil passage S2, Figure 17B is a diagram showing a valve timing adjustment device 100B according to embodiment 2 and is a front view showing the internal structure when hydraulic pressure is transmitted to the second oil passage S2, and Figure 18 is an enlarged view of the valve timing adjustment device 100B according to embodiment 2 and is an enlarged view of D in Figure 17B.

When hydraulic pressure is not transmitted to the first oil passage S1 but is transmitted to the second oil passage S2, the hydraulic pressure in the retard hydraulic chamber S4 pushes the second check valve 26B in the F direction to an open state, and the hydraulic pressure in the retard hydraulic chamber S4 pushes the first check valve 25B to a closed state, resulting in the state shown in Figures 17A, 17B, and 18. In this state, hydraulic pressure from the retard hydraulic chamber S4 is transmitted in the G direction, and the lock pin 32 moves from the restricted position to the permitted position. In this state, the retard hydraulic chamber S4 and the lock pin release chamber S5 are also in communication with each other.

The first check valve 25B and the second check valve 26B are formed to have a circular shape when viewed in the direction of the rotation axis L1, but are not limited to this. The first check valve and the second check valve only need to be configured to switch between a state in which the pressure of the working fluid is permitted to be transmitted and a state in which the pressure of the working fluid is restricted to be transmitted between the advance hydraulic chamber S3, the retard hydraulic chamber S4, and the lock pin release chamber S5, and may be formed to have a shape other than a circular shape when viewed in the direction of the rotation axis L1.

Embodiment 3.
Next, a valve timing control device 100C according to a third embodiment will be described with reference to Figures 19 and 20. The valve timing control device 100C according to the third embodiment differs from the valve timing control device 100B according to the second embodiment in the shapes of the first check valve and the second check valve, but other shapes and configurations are similar, and therefore the same processes and configurations as those in the second embodiment are denoted by the same reference numerals and description thereof will be omitted.

Figure 19 is a front view showing the internal structure of the valve timing adjustment device 100C of embodiment 3 when hydraulic pressure is not being transmitted, and Figure 20 is an enlarged view of the valve timing adjustment device 100C of embodiment 3, which is an enlarged view of D in Figure 19.

The rotor 20C of the valve timing adjustment device 100C according to the third embodiment has a rotor body 21B arranged in the space S0, a holder 22, a first check valve 25C and a second check valve 26C, a pair of valve springs 27B, 27B that bias the first check valve 25C and the second check valve 26C, and a spring holder 24B that holds the valve springs 27B, 27B. The first check valve 25C and the second check valve 26C are formed to be substantially trapezoidal when viewed in the direction of the rotation axis L1. Thus, various shapes are possible for the first check valve and the second check valve. In the third embodiment, the rotor 20C, the first check valve 25C, and the second check valve 26C respectively constitute a second rotating body, a first valve, and a second valve.

In addition, this disclosure allows for free combinations of the embodiments, or modifications to any of the components of each embodiment, or the omission of any of the components in each embodiment.

The valve timing adjustment device disclosed herein can be used, for example, to improve the fuel efficiency of an internal combustion engine by adjusting the opening and closing timing of the valves of the engine.

Various aspects of this disclosure are summarized below as appendices.

(Appendix 1)
a first rotor that rotates in response to rotation of a crankshaft of the internal combustion engine;
a second rotor that is rotatably supported relative to the first rotor between a first position and a second position and rotates together with the first rotor to transmit a rotational force of the first rotor to a camshaft that opens and closes a valve of the internal combustion engine;
a rotation limiting member that moves between a limiting position that limits rotation of the second rotating body relative to the first rotating body when the second rotating body is located at a third position between the first position and the second position, and an allowing position that allows rotation of the second rotating body relative to the first rotating body,
the first rotor defines a first space and a second space to which pressure of a working fluid is transmitted between the first rotor and the second rotor,
the second rotor rotates between the first position and the second position due to a pressure difference of the working fluid between the first space and the second space,
the rotation limiting member is disposed so as to be exposed to a third space to which pressure of the working fluid from the first space and the second space can be transmitted, and moves between the restricting position and the allowing position in response to a change in pressure of the working fluid transmitted to the third space.
(Appendix 2)
2. The valve timing adjusting device according to claim 1, wherein when the rotation limiting member is located at the limiting position and pressure of the working fluid is transmitted from at least one of the first space and the second space to the third space, the rotation limiting member moves from the limiting position to the allowing position by the pressure of the working fluid transmitted to the third space.
(Appendix 3)
a first valve that switches between a state in which the transmission of pressure of the working fluid between the first space and the third space is permitted and a state in which the transmission of pressure of the working fluid between the first space and the third space is restricted;
a second valve configured to switch between a state allowing transmission of pressure of working fluid between the second space and the third space and a state restricting transmission of pressure of working fluid between the second space and the third space.
(Appendix 4)
4. The valve timing adjusting device according to claim 1, further comprising a biasing member that biases the second rotating body to rotate toward the third position in a state in which the second rotating body is located between the first position and the third position.
(Appendix 5)
the second rotating body can be maintained in a state positioned between the first position and the second position by a biasing force of the biasing member and a rotational force received from the crankshaft that rotates the second rotating body from the second position toward the third position when the rotation limiting member is positioned at the permissible position.
(Appendix 6)
6. The valve timing adjusting device according to claim 1, wherein the rotation limiting member is supported movably along a rotation axis of the second body of rotation relative to the first body of rotation.
(Appendix 7)
4. The valve timing adjusting device according to claim 3, wherein at least one of the first valve and the second valve is supported movably along a rotation axis of the second rotor relative to the first rotor.
(Appendix 8)
the second rotating body has a partition portion that separates the first space and the second space,
The valve timing adjusting device according to claim 7, wherein at least a portion of the rotation limiting member is disposed inside the partition portion.
(Appendix 9)
The valve timing adjusting device according to claim 8, wherein the third space, the first valve, and the second valve are disposed in the partition portion.
(Appendix 10)
10. The valve timing adjusting device according to claim 8 or 9, wherein the first valve and the second valve are disposed in a gap formed between an inner surface of the first rotor and the partition portion in a radial direction of rotation of the second rotor relative to the first rotor, and open and close the gap.
(Appendix 11)
11. The valve timing adjusting device according to claim 10, wherein the first valve and the second valve open and close the gap by moving along a direction intersecting a rotation axis of the second rotor relative to the first rotor and the radial direction.
(Appendix 12)
12. A valve timing adjusting device according to any one of claims 1 to 11, comprising: a sleeve; a spool housed inside the sleeve and moving relative to the sleeve; and a drive unit that drives the spool, and further comprising a pressure control unit that controls a pressure difference of working fluid between the first space and the second space in accordance with a position of the spool relative to the sleeve.

2 Camshaft, 10 Housing (first rotating body), 11 Sprocket portion, 12 Case, 13 First plate, 14 Second plate, 15 Bush, 20, 20B, 20C Rotor (second rotating body), 21, 21B Rotor body, 22 Holder, 24 Valve guide, 24B Spring holder, 25, 25B First check valve (first valve), 26, 26B Second check valve (second valve), 27, 27B Valve spring, 31 Spiral spring, 32 Lock pin (rotation limiting member), 33 Lock pin spring, 50 Oil control valve (OCV, pressure control unit), 51 Sleeve, 52 Spool, 53 Spool spring, 100A, 100B, 100C Valve timing adjustment device, 120 Case cylindrical portion, 121 First shoe, 122 Second shoe, 123 Third shoe, 124 fourth shoe, 131 first spring retaining portion, 132 second spring retaining portion, 210 rotor cylindrical portion, 211, 211B first vane (partition portion), 212 second vane (partition portion), 213 third vane (partition portion), 214 fourth vane (partition portion), 221 lever, 311 one end, 312 other end, B direction, C direction, E direction, F direction, G direction, L1 rotation axis, R1 advance direction (rotation direction), R2 retard direction (rotation direction), S0 space, S1 first oil passage, S2 second oil passage, S3 advance hydraulic chamber (first space) S4 retard hydraulic chamber (second space) S5 lock pin release chamber (third space).

Claims (10)

a first rotor that rotates in response to rotation of a crankshaft of the internal combustion engine;
a second rotor that is rotatably supported relative to the first rotor between a first position and a second position and rotates together with the first rotor to transmit a rotational force of the first rotor to a camshaft that opens and closes a valve of the internal combustion engine;
a rotation limiting member that moves between a limiting position that limits rotation of the second rotating body relative to the first rotating body when the second rotating body is located at a third position between the first position and the second position, and an allowing position that allows rotation of the second rotating body relative to the first rotating body;
a first valve that switches between a state in which the transmission of pressure of the working fluid between a first space and a third space is permitted and a state in which the transmission of pressure of the working fluid between the first space and the third space is restricted;
a second valve that switches between a state in which the pressure of the working fluid is permitted to be transmitted between the second space and the third space and a state in which the pressure of the working fluid is restricted to be transmitted between the second space and the third space,
the first rotor defines the first space and the second space between the first rotor and the second rotor, through which pressure of a working fluid is transmitted;
the second rotor rotates between the first position and the second position due to a pressure difference of the working fluid between the first space and the second space,
the rotation limiting member is disposed so as to be exposed to the third space through which pressure of the working fluid from the first space and the second space can be transmitted, and moves between the limiting position and the allowing position in response to a change in pressure of the working fluid transmitted to the third space ;
a valve timing adjusting device, characterized in that, when the pressure of the working fluid is transmitted from at least one of the first space and the second space to the third space while the rotation limiting member is located at the limiting position, the rotation limiting member moves from the limiting position to the permissible position by the pressure of the working fluid transmitted to the third space . 2. The valve timing adjusting device according to claim 1, further comprising a biasing member that biases the second rotor to rotate toward the third position when the second rotor is located between the first position and the third position. 3. The valve timing adjusting device according to claim 2, wherein the second rotor can be maintained in a state between the first position and the second position by the biasing force of the biasing member and the rotational force received from the crankshaft when the rotation limiting member is positioned at the permitted position. 4. The valve timing adjusting device according to claim 3, wherein the rotation limiting member is supported movably along a rotation axis of the second body of rotation relative to the first body of rotation. 2. The valve timing adjusting device according to claim 1, wherein at least one of the first valve and the second valve is supported movably along a rotation axis of the second rotor relative to the first rotor. the second rotating body has a partition portion that separates the first space and the second space,
The valve timing adjusting device according to claim 5, wherein at least a portion of the rotation limiting member is disposed inside the partition portion. The valve timing adjusting device according to claim 6, wherein the third space, the first valve, and the second valve are disposed in the partition portion. 8. The valve timing adjusting device according to claim 7, wherein the first valve and the second valve are arranged in a gap formed between an inner surface of the first rotor and the partition portion in a radial direction of rotation of the second rotor relative to the first rotor, and open and close the gap. 9. The valve timing adjusting device according to claim 8, wherein the first valve and the second valve open and close the gap by moving along a direction intersecting a rotation axis of the second rotor relative to the first rotor and the radial direction. 10. A valve timing adjusting device according to claim 1, further comprising: a sleeve; a spool housed inside the sleeve and moving relative to the sleeve; and a drive unit that drives the spool, and further comprising a pressure control unit that controls a pressure difference between the first space and the second space in accordance with a position of the spool relative to the sleeve .

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