VALVE TIMING ADJUSTMENT DEVICE

TECHNICAL FIELD

The present invention relates to a valve timing adjustment device.

BACKGROUND ART

A hydraulic variable valve timing adjustment device, which controls opening and closing timing of an intake valve or an exhaust valve of an internal combustion engine for an automobile, is generally known. A hydraulic variable valve timing adjustment device includes a housing, which rotates in synchronization with a crankshaft, and a vane rotor, which rotates in synchronization with a camshaft. The vane of the vane rotor divides each of a plurality of hydraulic chambers inside the housing into either a retard chamber or an advance chamber. The hydraulic variable valve timing adjustment device controls the opening and closing timing of the intake valve or the exhaust valve by supplying the hydraulic oil to the retard chamber or the advance chamber to change the rotational phase of the vane rotor with respect to the housing to the retard side or the advance side.

In order to lock the rotational phase of the vane rotor with respect to the housing to a specific phase at the time of starting the internal combustion engine, the valve timing adjustment device as described above has a mechanism for applying an assist torque to the vane rotor so as to change the rotational phase to the specific phase when the internal combustion engine is stopped (hereinafter, the specific phase is referred to as a lock phase). An example of a valve timing adjustment device having such a mechanism is the valve timing adjustment device described in Patent Literature 1. The valve timing adjustment device includes: a front plate installed in a housing; a bush which is a holder installed on a rotating shaft of a vane rotor; and a spiral spring whose innermost peripheral portion is wound around the bush.

The front plate includes a first stopper that is a projection portion. In a case where the rotational phase described above changes to the retard side, the outermost peripheral portion of the spiral spring is caught by the first stopper and the spiral spring urges the vane rotor toward the advance side. As a result, the vane rotor rotates relative to the housing, and the rotational phase described above thus returns to the intermediate phase. Moreover, the bush includes an arm having a second stopper which is a projection portion. In a case where the rotational phase described above changes to the advance side, the spiral spring does not urge the vane rotor because the outermost peripheral portion thereof is caught by the second stopper and the spiral spring is separated from the first stopper.

CITATION LIST
Patent Literature

Patent Literature 1: JP 2010-180862A

SUMMARY OF INVENTION
Technical Problem

In the valve timing adjustment device described in Patent Literature 1 as described above, there is a problem that vibration of the engine during operation is transmitted to the spiral spring, and the spiral spring is damaged or dropped due to resonance.

The present invention has been made to solve the above problem, and an object of the present invention is to provide a technique for suppressing resonance of a spiral spring due to vibration of an engine during operation.

Solution to Problem

A valve timing adjustment device according to present invention includes: a first rotating body that rotates synchronously with a crankshaft; and a second rotating body that rotates synchronously with a camshaft. The first rotating body includes a plate having an opening portion around a rotation axis. The second rotating body includes: a main body portion that is disposed to pass through the opening portion of the plate and is disposed around the rotation axis; and a holder having a first arm and a second arm that each extends to an outer peripheral side from an end portion of a part of the main body portion projecting from a front surface of the plate. A spiral spring is installed between the front surface of the plate and the first and the second arms, in which the spiral spring is wound around the main body portion, an inner peripheral side end portion of the spiral spring is held by the plate, and a terminal hook portion of the spiral spring is formed by bending an outer peripheral side end portion toward an outer peripheral side. A first arm projection portion is caught by the terminal hook portion of the spiral spring, is urged toward a lock phase side by the spiral spring and is installed on a face opposite to the front surface of the plate in the first arm in a case where a rotational phase of the second rotating body with respect to the first rotating body is on a first rotational phase side. A second arm projection portion abuts on an outermost peripheral portion of the spiral spring and is installed on a face opposite to the front surface of the plate in the second arm in a case where the rotational phase is on the first rotational phase side.

Advantageous Effects of Invention

According to the present invention, it is possible to suppress resonance of the spiral spring due to vibration of the engine during operation.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view illustrating the configuration of a valve timing adjustment device according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a cross section of the valve timing adjustment device illustrated in FIG. 1 taken along dotted line A.

FIG. 3 is a front view illustrating the configuration of the valve timing adjustment device in a case where a rotational phase of a second rotating body with respect to a first rotating body is a first rotational phase.

FIG. 4 is a front view illustrating the configuration of the valve timing adjustment device in a case where the rotational phase of the second rotating body with respect to the first rotating body is in the second rotational phase side.

FIG. 5 is a graph illustrating a change in assist torque in accordance with a change in the rotational phase of the second rotating body with respect to the first rotating body.

FIG. 6A is a front view illustrating a holder included in the valve timing adjustment device according to a first modification. FIG. 6B is a cross-sectional view of the holder illustrated in FIG. 6A taken along line B.

FIG. 7 is a graph illustrating a change in a load applied to an unequal pitch spring in accordance with a change in the rotational phase of the second rotating body with respect to the first rotating body.

FIG. 8A is a front view illustrating a plate included in the valve timing adjustment device according to a second modification. FIG. 8B is a cross-sectional view of the plate illustrated in FIG. 8A taken along line C.

FIG. 9A is a front view illustrating the configuration of a valve timing adjustment device including a spiral spring according to a third modification. FIG. 9B is a diagram illustrating only a terminal hook portion, a terminal hook catching portion, and a first arm projection portion of the spiral spring in the valve timing adjustment device illustrated in FIG. 9A.

FIG. 10A illustrates the configuration of the valve timing adjustment device illustrated in FIG. 9A in which a rotational phase of the second rotating body with respect to the first rotating body is on a first rotational phase side. FIG. 10B is a diagram illustrating only the terminal hook portion, the terminal hook catching portion, and a first arm projection portion of the spiral spring in the valve timing adjustment device 100 illustrated in FIG. 10A.

DESCRIPTION OF EMBODIMENTS

Hereinafter, in order to explain the present invention in more detail, an embodiment for carrying out the present invention will be described with reference to the accompanying drawings.

First Embodiment

FIG. 1 is a plan view illustrating the configuration of a valve timing adjustment device 100 according to a first embodiment. FIG. 2 is a cross-sectional view illustrating a cross section of the valve timing adjustment device 100 illustrated in FIG. 1 taken along dotted line A. As illustrated in FIG. 1 or 2, the valve timing adjustment device 100 includes: a plate 1 having an opening portion 1a around a rotation axis R; a case 2 fixed to the back surface of the plate 1; a rotor 3 installed inside the case 2; and a holder 4 having a main body portion 4a passing through the opening portion 1a of the plate 1 and disposed around the rotation axis R. Note that, hereinafter, a surface of the plate 1 to which the case 2 is fixed is referred to as a back surface, and a surface of the plate 1 opposite to the back surface is referred to as a front surface.

More specifically, the valve timing adjustment device 100 has a chain sprocket portion 2a on the outer peripheral surface of the case 2. A chain (not illustrated) is attached to the chain sprocket portion 2a, and a driving force of a crankshaft of the internal combustion engine is transmitted to the chain sprocket portion 2a via the chain. Thus, the case 2 and the plate 1 fixed to the case 2 constitute a first rotating body that rotates synchronously with the crankshaft.

The main body portion 4a of the holder 4 has a cylindrical shape with one bottom face opened, and the other bottom face of the cylinder is fixed to the holder 4 by a center bolt 5. The rotor 3 is fastened to a camshaft of an internal combustion engine (not shown) by the center bolt 5 together with the main body portion 4a of the holder 4. Thus, the rotor 3 and the holder 4 constitute a second rotating body that rotates synchronously with the camshaft.

Moreover, the case 2 forms a plurality of hydraulic chambers inside, and the rotor 3 functions as a vane rotor and divides each hydraulic chamber of the case 2 into an advance side hydraulic chamber and a retard side hydraulic chamber. The plate 1 seals each of the advance side hydraulic chamber and the retard side hydraulic chamber.

When the hydraulic oil is supplied to or discharged from the advance side hydraulic chamber or the retard side hydraulic chamber, the second rotating body rotates to the advance side or the retard side with respect to the first rotating body. As a result, the rotational phase of the camshaft with respect to the crankshaft changes to the advance side or the retard side, and the opening and closing timing of an intake valve or an exhaust valve change. Note that, hereinafter, a direction in which the second rotating body rotates clockwise with respect to the first rotating body is referred to as an advance side, and a direction in which the second rotating body rotates counterclockwise is referred to as a retard side. Moreover, the rotational phase of the second rotating body with respect to the first rotating body in the valve timing adjustment device 100 illustrated in FIG. 1 is an intermediate phase between the advance side phase and the retard side phase, and in the first embodiment, the intermediate phase is set as a lock phase.

Next, a mechanism in which the valve timing adjustment device 100 according to the first embodiment applies an assist torque to the second rotating body when the internal combustion engine is stopping, will be described. As illustrated in FIG. 1 or 2, the holder 4 includes a first arm 4b and a second arm 4c, which extend to the outer peripheral side from the end portion of the portion of the main body portion 4a projecting from the front surface of the plate 1. Note that, hereinafter, the “outer periphery” of the “outer peripheral side” means the outer periphery of a circle when the shape of the valve timing adjustment device 100 is regarded as the circle in a case where the valve timing adjustment device 100 is viewed from the front as illustrated in FIG. 1.

A spiral spring 6 wound around the main body portion 4a is installed between the front surface of the plate 1 and the first arm 4b and the second arm 4c. More specifically, the spiral spring 6 is wound around the main body portion 4a so as to be gradually apart from the rotation axis R from one end portion toward the other end portion. Hereinafter, the one end portion is referred to as an inner peripheral side end portion, and the other end portion is referred to as an outer peripheral side end portion. Furthermore, the spiral spring 6 is wound around the main body portion 4a so that the inner peripheral portion and the corresponding outer peripheral portion do not come into contact with each other at any position. As a result, the spiral spring 6 has a spiral structure in which friction hardly occurs.

The inner peripheral side end portion of the spiral spring 6 is held by the plate 1. More specifically, the starting end hook portion 6a is formed by bending the inner peripheral side end portion of the spiral spring 6 toward the rotation axis R. A starting end hook catching portion 1b is installed on the front surface of the plate 1. The starting end hook portion 6a is held by the plate 1 by being caught by the starting end hook catching portion 1b.

The spiral spring 6 has a terminal hook portion 6b formed by bending the outer peripheral side end portion toward the outer peripheral side. On the front surface of the plate 1, a terminal hook catching portion 1c is installed. As in the valve timing adjustment device 100 illustrated in FIG. 1, when the rotational phase of the second rotating body with respect to the first rotating body is the lock phase, the terminal hook portion 6b is held by the plate 1 by being caught by the terminal hook catching portion 1c. Note that, at this time, no assist torque is applied to the second rotating body.

A first plate projection portion 1d is installed on the front surface of the plate 1. As in the valve timing adjustment device 100 illustrated in FIG. 1, when the rotational phase of the second rotating body with respect to the first rotating body is the lock phase, the first plate projection portion 1d abuts on the outermost peripheral portion of the spiral spring. As a result, the vibration of the engine transmitted to the spiral spring 6 through the terminal hook catching portion 1c is transmitted from the portion in contact with the terminal hook catching portion 1c to the portion in contact with the first plate projection portion 1d on the outermost periphery of the spiral spring 6, but is hardly transmitted beyond the latter portion.

On the front surface of the plate 1, a second plate projection portion 1e that abuts on the innermost peripheral portion of the spiral spring 6 is installed. Accordingly, when the spiral spring 6 is wound around the main body portion 4a of the holder 4, the second plate projection portion 1e serves as a guide. More specifically, the starting end hook portion 6a is hooked on the starting end hook catching portion 1b, and a portion of the spiral spring 6 extending from the starting end hook portion 6a is brought into contact with the second plate projection portion 1e and wound around the main body portion 4a of the holder 4. Furthermore, the vibration of the engine transmitted to the spiral spring 6 through the starting end hook catching portion 1b is transmitted from the portion in contact with the starting end hook catching portion 1b to the portion in contact with the second plate projection portion 1e on the innermost periphery of the spiral spring 6, but is hardly transmitted beyond the latter portion.

More specifically, as for the arrangement of the second plate projection portion 1e, the second plate projection portion 1e is installed on the front surface of the plate 1 in a region from the starting end hook catching portion 1b up to 180 degrees toward the direction in which the spiral spring 6 is wound with reference to the rotation axis R. Accordingly, in a case where the second plate projection portion 1e is used as a guide, the spiral spring 6 is easily wound around the main body portion 4a of the holder 4. Furthermore, the spiral spring 6 can limit a region to which the vibration of the engine is transmitted.

As for the arrangement of the first plate projection portion 1d, more specifically, the first plate projection portion 1d is installed on the front surface of the plate 1 on the side opposite to the second plate projection portion 1e with reference to the rotation axis R. Further more specifically, in a case where a line connecting the second plate projection portion 1e and the rotation axis R at the shortest distance is defined as a line α, a line perpendicular to the line α and orthogonal to the rotation axis R is defined as a line β, and the front surface of the plate 1 is divided into a region including the second plate projection portion 1e and a region not including the second plate projection portion 1e with the line β as a boundary, the first plate projection portion 1d is installed in the region not including the second plate projection portion 1e.

As a result, the first plate projection portion 1d becomes an obstacle to the spiral spring 6, and the center of the spiral structure is less likely to be eccentric to the side opposite to the second plate projection portion 1e side with reference to the rotation axis R. More specifically, when the spiral spring 6 moves to the side opposite to the second plate projection portion 1e with reference to the rotation axis R while the innermost circumference of the spiral spring 6 abuts on the second plate projection portion 1e, a portion of the spiral spring 6 abuts on the second plate projection portion 1e and a portion on the outer circumferential side corresponding to the portion come into contact with each other, which causes a problem of friction.

Therefore, as described above, since the first plate projection portion 1d is installed in the region not including the second plate projection portion 1e, the first plate projection portion 1d becomes an obstacle, the spiral spring 6 hardly moves to the side opposite to the second plate projection portion 1e side with reference to the rotation axis R, and the portion of the spiral spring 6 in contact with the second plate projection portion 1e and the portion on the outer peripheral side corresponding to the portion hardly come into contact with each other, so that friction is hardly generated.

Next, the valve timing adjustment device 100 in a case where the rotational phase of the second rotating body with respect to the first rotating body is on a first rotational phase side will be described with reference to the drawings. FIG. 3 is a front view illustrating the configuration of the valve timing adjustment device 100 in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side. Note that, in the first embodiment, the first rotational phase side is a retard side with reference to the intermediate phase.

As illustrated in FIG. 1, FIG. 2 or FIG. 3, a first arm projection portion 4d is installed on a surface of the first arm 4b facing the front surface of the plate 1. As in the valve timing adjustment device 100 illustrated in FIG. 3, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the first arm projection portion 4d is caught by the terminal hook portion 6b of the spiral spring 6 and urged toward the lock phase side by the spiral spring 6. Note that, herein, the lock phase side is an advance side.

More specifically, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the intermediate phase which is the lock phase to the retard side which is the first rotational phase side, the first arm projection portion 4d is caught by the terminal hook portion 6b of the spiral spring 6, thereby the terminal hook portion 6b is separated from the terminal hook catching portion 1c. The spiral spring 6 is deformed when the first arm projection portion 4d is caught by the terminal hook portion 6b. The deformed spiral spring 6 urges the first arm projection portion 4d toward the advance side which is the lock phase side by the restoring force. As a result, the assist torque is applied to the second rotating body, and the rotational phase of the second rotating body with respect to the first rotating body changes from the first rotational phase side to the intermediate phase that is the lock phase.

Moreover, a second arm projection portion 4e is installed on a surface of the second arm 4c facing the front surface of the plate 1. As in the valve timing adjustment device 100 illustrated in FIG. 3, when the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the second arm projection portion 4e abuts on the outermost peripheral portion of the spiral spring 6.

More specifically, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the intermediate phase, which is the lock phase, to the retard side, which is the first rotational phase side, the second arm projection portion 4e gradually moves toward the spiral spring 6 side while moving toward the retard side along the locus T in a state of abutting on the outermost peripheral portion of the spiral spring 6, and urges the portion toward the rotation axis R, thereby the outermost peripheral portion of the spiral spring 6 is deformed and separated from the first plate projection portion 1d. This eliminates friction between the outermost peripheral portion of the spiral spring 6 and the first plate projection portion 1d.

Moreover, in this process, the outermost peripheral portion of the spiral spring 6 is deformed by the terminal hook portion 6b being caught by the first arm projection portion 4d, and moves rotationally to the retard side by the amount of movement of the first arm projection portion 4d to the retard side. That is, in the process, the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6 both move to the retard side while being in contact with each other. Therefore, friction hardly occurs between the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6. Furthermore, when the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6 abut on each other, the vibration of the engine transmitted to the spiral spring 6 via the terminal hook catching portion 1c is transmitted from the portion in contact with the terminal hook catching portion 1c at the outermost periphery of the spiral spring 6 to the portion in contact with the second arm projection portion 4e but is hardly transmitted beyond the latter portion.

More specifically, as for the above-described arrangement of the second arm projection portion 4e, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the second arm projection portion 4e is located on the side opposite to the second plate projection portion 1e side with reference to the rotation axis R. More specifically, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the second arm projection portion 4e is installed in the region of the front surface of the plate 1 that does not include the second plate projection portion 1e with the above-described line β as a boundary.

As a result, in the spiral spring 6, the second arm projection portion 4e becomes an obstacle, and the center of the spiral structure is less likely to be eccentric to the side opposite to the second plate projection portion 1e side with reference to the rotation axis R. More specifically, the second arm projection portion 4e becomes an obstacle, the spiral spring 6 is less likely to move to the side opposite to the second plate projection portion 1e side with reference to the rotation axis R, a portion of the spiral spring 6 in contact with the second plate projection portion 1e and a portion on the outer peripheral side corresponding to the portion are less likely to come into contact, and friction is less likely to occur.

Next, the valve timing adjustment device 100 in a case where the rotational phase of the second rotating body with respect to the first rotating body is on a second rotational phase side will be described with reference to the drawings. FIG. 4 is a front view illustrating the configuration of the valve timing adjustment device 100 in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side. Note that, in the first embodiment, the second rotational phase side is an advance side with reference to the intermediate phase.

As in the valve timing adjustment device 100 illustrated in FIG. 4, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side, the terminal hook portion 6b is held by the plate 1 by being caught by the terminal hook catching portion 1c. More specifically, when the rotational phase of the second rotating body with respect to the first rotating body changes from the retard side, which is the first rotational phase side, to the intermediate phase, which is the lock phase, the terminal hook portion 6b is caught by the terminal hook catching portion 1c to be separated from the first arm projection portion 4d. Then, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the intermediate phase, which is the lock phase, to the advance side, which is the second rotational phase side, the terminal hook portion 6b is further separated from the first arm projection portion 4d. As a result, the assist torque by the spiral spring 6, which is described above, is not applied to the second rotating body.

Moreover, as in the valve timing adjustment device 100 illustrated in FIG. 4, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side, the first plate projection portion 1d abuts on the outermost peripheral portion of the spiral spring. More specifically, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the retard side, which is the first rotational phase side, to the intermediate phase, which is the lock phase, the second arm projection portion 4e moves so as to be gradually apart from the spiral spring 6 side while moving to the advance side along the locus T in a state of abutting on the outermost peripheral portion of the spiral spring 6, thereby the outermost periphery of the spiral spring 6 gradually returns to the original shape by the restoring force. Then, when the rotational phase of the second rotating body with respect to the first rotating body reaches the intermediate phase that is the lock phase, the outermost periphery of the spiral spring 6 abuts on the first plate projection portion 1d. When the rotational phase reaches the advance side which is the second rotational phase side, the second arm projection portion 4e is completely separated from the outermost periphery of the spiral spring 6.

Furthermore, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the retard side, which is the first rotational phase side, to the intermediate phase, which is the lock phase, the outermost peripheral portion of the spiral spring 6 returns to the original shape by the restoring force and moves to the advance side as the terminal hook portion 6b is separated from the first arm projection portion 4d. That is, in the process, the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6 are separated from each other while moving toward the advance side. As a result, friction is less likely to occur between the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6. Moreover, since the outermost periphery of the spiral spring 6 abuts on the first plate projection portion 1d, the vibration of the engine transmitted to the spiral spring 6 via the terminal hook catching portion 1c is transmitted from the portion in contact with the terminal hook catching portion 1c to the portion in contact with the first plate projection portion 1d on the outermost periphery of the spiral spring 6, but is hardly transmitted beyond the latter portion.

As described above, the second arm projection portion 4e is configured to be separated from the outermost periphery of the spiral spring 6 in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side. For example, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side, the arrangement of the second arm projection portion 4e and the second arm 4c is adjusted so as to be separated from the outermost periphery of the spiral spring 6. Alternatively, for example, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side, the curvature of the spiral spring 6 wound around the main body portion 4a on the outermost periphery of the spiral spring 6 is adjusted so as to be separated from the outermost periphery of the spiral spring 6.

As described above, the valve timing adjustment device 100 according to the first embodiment applies the assist torque to the second rotating body by the spiral spring 6 in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side. In a case where the rotational phase is on the second rotational phase side, the assist torque is not applied to the second rotating body. FIG. 5 is a graph illustrating a change in assist torque in accordance with a change in the rotational phase of the second rotating body with respect to the first rotating body. The vertical axis in FIG. 5 represents the assist torque to the second rotating body, and the horizontal axis in FIG. 5 represents the rotational phase of the second rotating body with respect to the first rotating body. Note that the assist torque illustrated in FIG. 5 is also in consideration of friction against the spiral spring 6 or the second rotating body.

As illustrated in FIG. 5, the assist torque applied to the second rotating body continues to increase in the course of the rotational phase of the second rotating body with respect to the first rotating body changing from the intermediate phase to the retard side, which is on the first rotational phase side, and reaching the maximum retarded phase. More specifically, in the process, the spiral spring 6 in which the terminal hook portion 6b is caught by the first arm projection portion 4d is gradually deformed, and the assist torque to the second rotating body increases as the restoring force increases.

Furthermore, on the other hand, in the course of the rotational phase of the second rotating body with respect to the first rotating body from the most retarded phase to the intermediate phase, the assist torque to the second rotating body continues to decrease. More specifically, in the process, the spiral spring 6 in which the terminal hook portion 6b is caught by the first arm projection portion 4d gradually returns to the original shape, and the restoring force decreases, so that the assist torque to the second rotating body decreases.

As described above, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the intermediate phase, which is the lock phase, to the retard side, which is on the first rotational phase side, the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6 both move to the retard side in a state of being in contact with each other. Moreover, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the retard side, which is the first rotational phase side, to the intermediate phase, which is the lock phase, the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6 are separated from each other while moving toward the advance side together.

As a result, friction hardly occurs between the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6, so that it is possible to suppress hysteresis generated between a process, in which the rotational phase of the second rotating body with respect to the first rotating body changes from the intermediate phase that is the lock position, to the retard side that is the first rotational phase side, and a process in which that rotational phase changes from the retard side that is the first rotational phase side to the intermediate phase that is the lock position.

Further, when the rotational phase of the second rotating body with respect to the first rotating body reaches the intermediate phase from the most retarded phase, the terminal hook portion 6b is caught by the terminal hook catching portion 1c, so that the assist torque to the second rotating body becomes substantially zero. Then, the assist torque to the second rotating body maintains substantially zero in a process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the intermediate phase, which is the lock phase, to the advance side, which is the second rotational phase side, and reaches the most advanced phase, and in a process in which the rotational phase changes from the most advanced phase to the intermediate phase, which is the lock phase.

As described above, the second arm projection portion 4e is configured to be separated from the outermost periphery of the spiral spring 6 in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side. Therefore, friction hardly occurs between the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6. Therefore, it is possible to suppress hysteresis generated between a process, in which the rotational phase of the second rotating body with respect to the first rotating body changes from the intermediate phase that is the lock phase to the advance side that is the second rotational phase side, and a process in which the rotational phase changes from the advance side that is the second rotational phase side to the intermediate phase that is the lock position.

Next, a first modification example of the valve timing adjustment device 100 according to the first embodiment will be described with reference to the drawings. FIG. 6A is a front view illustrating a holder 10 included in the valve timing adjustment device 100 according to the first modification example. FIG. 6B is a cross-sectional view of holder 10 illustrated in FIG. 6A taken along line B. As illustrated in FIGS. 6A and 6B, an unequal pitch spring 11 is installed in a second arm projection portion 10a of the holder 10.

More specifically, the second arm 10b of the holder 10 has a through hole 10c, and the second arm projection portion 10a is movably held between the inner wall on the outer peripheral side and the inner wall on the rotation axis R side of the through hole 10c. Further, an unequal pitch spring 11 is installed between the inner wall of the through hole 10c on the outer peripheral side and the second arm projection portion 10a. When the second arm projection portion 10a abuts on the outermost peripheral portion of the spiral spring 6 and is pressed toward the outer peripheral side, the unequal pitch spring 11 urges the second arm projection portion 10a toward the rotation axis R side.

FIG. 7 is a graph illustrating a change in the load applied to the unequal pitch spring 11, that is, a change in the restoring force by the unequal pitch spring 11 according to a change in the rotational phase of the second rotating body with respect to the first rotating body. Note that, in the first modification example, for the sake of explanation, it is assumed that the second arm projection portion 10a is in contact with the outermost peripheral portion of the spiral spring 6 even when the rotational phase of the second rotating body with respect to the first rotating body is on the advance side which is the second rotational phase side. The vertical axis in FIG. 7 indicates the restoring force by the unequal pitch spring 11, and the horizontal axis in FIG. 7 indicates the rotational phase of the second rotating body with respect to the first rotating body.

First, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the intermediate phase that is the lock phase to the retard side that is the first rotational phase side, the second arm projection portion 10a is pushed toward the outer peripheral side by the spiral spring 6 while moving toward the retard side in a state of being in contact with the outermost peripheral portion of the spiral spring 6, and moves gradually away from the rotation axis R side. In the process, the unequal pitch spring 11 contracts, and as shown in FIG. 7, the force for urging the outermost peripheral portion of the spiral spring 6 toward the rotation axis R via the second arm projection portion 10a gradually increases.

In addition, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the retard side, which is the first rotational phase side, to the intermediate phase, which is the lock phase, the second arm projection portion 10a moves to the advance side in a state of being in contact with the outermost peripheral portion of the spiral spring 6, and gradually moves closer to the rotation axis R side as the force of being pushed toward the outer peripheral side by the spiral spring 6 is weakened. In the process, the unequal pitch spring 11 extends, and as illustrated in FIG. 7, the force for urging the outermost peripheral portion of the spiral spring 6 toward the rotation axis R via the second arm projection portion 10a gradually decreases. Then, when the rotational phase of the second rotating body with respect to the first rotating body reaches the intermediate phase which is the lock phase or the advance side which is a second rotational phase, the force becomes substantially zero.

As described above, by using the unequal pitch spring 11, it is possible to suitably implement a configuration in which the second arm projection portion 10a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side when the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, and a configuration in which the second arm projection portion 10a does not urge the outermost peripheral portion of the spiral spring 6 when the rotational phase is on the second rotational phase side. Therefore, when the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the second arm projection portion 10a abuts on the outermost peripheral portion of the spiral spring, and it is possible to suppress resonance of the spiral spring due to vibration of the engine during operation. On the other hand, when the rotational phase is on the second rotational phase side, friction is less likely to occur between the second arm projection portion 10a and the outermost peripheral portion of the spiral spring 6.

In addition, the unequal pitch spring 11 serves as a buffer between the second arm projection portion 10a and the outermost peripheral portion of the spiral spring 6, and friction is less likely to occur between the second arm projection portion 10a and the outermost peripheral portion of the spiral spring 6. Therefore, the hysteresis described above can be suppressed. In addition, since the second arm projection portion 10a is movable with respect to the second arm 4c by the unequal pitch spring 11, the degree of freedom in designing the arrangement of the second arm projection portion 10a and the second arm 4c or the degree of freedom in designing the curvature wound around the main body portion 4a on the outermost periphery of the spiral spring 6 can be increased.

Note that each of the above effects can be implemented by using another type of spring such as an equal pitch spring, for example, as the spring installed in the second arm projection portion 10a instead of the unequal pitch spring 11. On the other hand, as in the first modification example, the following effects are obtained by using the unequal pitch spring 11 as the spring installed in the second arm projection portion 10a. That is, since the unequal pitch spring 11 has a non-linear relationship between the load and the deflection, in the graph of FIG. 7, the inclination when the rotational phase of the second rotating body with respect to the first rotating body is on the retard side which is the first rotational phase side is larger than the inclination when the rotational phase is on the advance side which is the second rotational phase side. That is, the spring constant of the unequal pitch spring 11 in the contracted state is larger than the spring constant in the state where substantially no load is applied. As a result, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the force by which the second arm projection portion 10a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side can be increased, and in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side, the force by which the second arm projection portion 10a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side can be decreased.

Next, a second modification example of the valve timing adjustment device 100 according to the first embodiment will be described with reference to the drawings. FIG. 8A is a front view illustrating a plate 12 included in a valve timing adjustment device 100 according to the second modification example. FIG. 8B is a cross-sectional view of the plate 12 illustrated in FIG. 8A taken along line C. As illustrated in FIGS. 8A and 8B, an unequal pitch spring 13 is installed in a first plate projection portion 12a.

More specifically, the plate 12 has a recess portion 12b, and the first plate projection portion 12a is movably held between the inner wall on the outer peripheral side and the inner wall on the rotation axis R side of the recess portion 12b. Moreover, the unequal pitch spring 13 is installed between the inner wall of the recess portion 12b on the outer peripheral side and the first plate projection portion 12a. When the first plate projection portion 12a abuts on the outermost peripheral portion of the spiral spring 6 and is pressed toward the outer peripheral side, the unequal pitch spring 13 urges the first plate projection portion 12a toward the rotation axis R side.

In the second modification example, for the sake of explanation, it is assumed that the first plate projection portion 12a is in contact with the outermost peripheral portion of the spiral spring 6 even when the rotational phase of the second rotating body with respect to the first rotating body is on the retard side which is the first rotational phase side. As described above, when the rotational phase of the second rotating body with respect to the first rotating body is on the advance side which is the second rotational phase side, the second arm projection portion 4e is completely separated from the outermost periphery of the spiral spring 6. As a result, the restoring force due to the outermost periphery of the spiral spring 6 is directly applied to the first plate projection portion 12a, and when the first plate projection portion 12a is pushed toward the outer peripheral side, the unequal pitch spring 13 contracts, and a force urging the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side via the first plate projection portion 12a is generated.

Further, as described above, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the intermediate phase which is the lock phase to the retard side which is the first rotational phase side, the second arm projection portion 4e moves so as to gradually approach the spiral spring 6 side while moving toward the retard side along the locus T in a state of abutting on the outermost peripheral portion of the spiral spring 6, and urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side. As a result, when the outermost peripheral portion of the spiral spring 6 is deformed and the force with which the portion pushes the first plate projection portion 12a toward the outer peripheral side is weakened, the unequal pitch spring 13 extends, and the force with which the outermost peripheral portion of the spiral spring 6 is urged toward the rotation axis R side via the first plate projection portion 12a becomes substantially 0.

As described above, by using the unequal pitch spring 13, it is possible to suitably implement a configuration in which the first plate projection portion 12a does not urge the outermost peripheral portion of the spiral spring 6 when the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, and a configuration in which the first plate projection portion 12a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side when the rotational phase is on the second rotational phase side. Therefore, when the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, friction is less likely to occur between the first plate projection portion 12a and the outermost peripheral portion of the spiral spring 6. On the other hand, when the rotational phase is on the second rotational phase side, the first plate projection portion 12a abuts on the outermost peripheral portion of the spiral spring, and it is possible to suppress resonance of the spiral spring due to vibration of the engine during operation.

Moreover, the unequal pitch spring 13 serves as a buffer between the first plate projection portion 12a and the outermost peripheral portion of the spiral spring 6, and friction is less likely to occur between the first plate projection portion 12a and the outermost peripheral portion of the spiral spring 6. In addition, since the first plate projection portion 12a is movable with respect to the plate 1 by the unequal pitch spring 13, the degree of freedom in designing the arrangement of the first plate projection portion 12a or the degree of freedom in designing the curvature wound around the main body portion 4a on the outermost periphery of the spiral spring 6 can be increased.

Note that each of the above effects can be implemented by using another type of spring such as an equal pitch spring, for example, as the spring installed in the first plate projection portion 12a instead of the unequal pitch spring 13. On the other hand, as in the second modification example, the following effects are obtained by using the unequal pitch spring 13 as the spring installed in the first plate projection portion 12a. That is, the spring constant of the unequal pitch spring 13 in the contracted state is larger than the spring constant in the state where substantially no load is applied. As a result, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the force by which the first plate projection portion 12a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side can be reduced, and in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side, the force by which the first plate projection portion 12a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side can be increased. Accordingly, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, friction is less likely to occur between the first plate projection portion 12a and the outermost peripheral portion of the spiral spring 6, and in a case where the rotational phase is on the second rotational phase side, the first plate projection portion 12a can suppress resonance of the spiral spring due to vibration of the engine during operation.

Next, a third modification example of the valve timing adjustment device 100 according to the first embodiment will be described with reference to the drawings. FIG. 9A is a front view illustrating the configuration of a valve timing adjustment device 100 including a spiral spring 14 instead of the spiral spring 6. FIG. 9B is a diagram illustrating only a terminal hook portion 14a, a terminal hook catching portion 1c, and a first arm projection portion 4d of the spiral spring 14 in the valve timing adjustment device 100 illustrated in FIG. 9A. Note that the rotational phase of the second rotating body with respect to the first rotating body in the valve timing adjustment device 100 illustrated in FIG. 9A is an intermediate phase which is a lock phase. Moreover, in FIGS. 9A and 9B, for the sake of explanation, the terminal hook catching portion 1c having a cylindrical shape is shown unlike the shape of the terminal hook catching portion 1c in FIG. 1 and the like, but the function is not changed.

As illustrated in FIGS. 9A and 9B, the terminal hook portion 14a of the spiral spring 14 according to the third modification example is formed by bending the outer peripheral side end portion of the spiral spring 14 toward the outer peripheral side by an angle larger than 90 degrees. In other words, an angle formed by the first portion 14b extending from the bent portion of the terminal hook portion 14a to the inner peripheral side end portion side and the second portion 14c extending to the outer peripheral side is an acute angle.

FIG. 10A illustrates the configuration of the valve timing adjustment device 100 illustrated in FIG. 9A in which the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side. FIG. 10B is a diagram illustrating only the terminal hook portion 14a, the terminal hook catching portion 1c, and the first arm projection portion 4d of the spiral spring 14 in the valve timing adjustment device 100 illustrated in FIG. 10A. As illustrated in FIGS. 9A and 9B and FIGS. 10A and 10B, the first arm projection portion 4d is caught by the terminal hook portion 14a of the spiral spring 14 in the process of changing the rotational phase of the second rotating body with respect to the first rotating body from the intermediate phase, which is the lock phase, to the retard side, which is the first rotational phase side. At this time, since the normal direction of the surface of the second portion 14c of the terminal hook portion 14a in contact with the first arm projection portion 4d is different from the moving direction of the first arm projection portion 4d, the second portion 14c of the terminal hook portion 14a is pushed toward the retard side by the first arm projection portion 4d and slides toward the outer peripheral side with respect to the first arm projection portion 4d at the same time. Then, the outermost peripheral portion of the spiral spring 14 is deformed by being pulled in the direction in which the terminal hook portion 14a slides toward the outer peripheral side, and is separated from the first plate projection portion 1d. This eliminates friction between the outermost peripheral portion of the spiral spring 14 and the first plate projection portion 1d.

The surface of the second portion 14c of the terminal hook portion 14a in contact with the first arm projection portion 4d and the surface of the first arm projection portion 4d in contact with the second portion 14c are preferably configured to be easily slidable against each other so that the second portion 14c of the terminal hook portion 14a slides toward the outer peripheral side with respect to the first arm projection portion 4d. For example, the surface of the second portion 14c of the terminal hook portion 14a in contact with the first arm projection portion 4d and the surface of the first arm projection portion 4d in contact with the second portion 14c are configured to be in point contact with each other.

Furthermore, as illustrated in FIGS. 9A and 9B and FIGS. 10A and 10B, in the terminal hook portion 14a, when the rotational phase of the second rotating body with respect to the first rotating body is the intermediate phase that is the lock phase, the end portion of the second portion 14c may be further bent so as to partially surround the terminal hook catching portion 1c and the first arm projection portion 4d. Accordingly, the terminal hook portion 14a is hardly detached from the terminal hook catching portion 1c or the first arm projection portion 4d.

Note that, in the first embodiment, the lock phase in the valve timing adjustment device 100 is the intermediate phase between the advanced phase and the retarded phase, but the lock phase is not limited thereto. For example, the lock phase in the valve timing adjustment device 100 may be an advance side phase or a retard side phase.

Moreover, in the first embodiment, the example in which the first rotational phase side in the valve timing adjustment device 100 is the retard side and the second rotational phase side is the advance side has been described. Then, the configuration has been described in which the rotational phase of the second rotating body with respect to the first rotating body is on the retard side, the first arm projection portion 4d is caught by the terminal hook portion 6b of the spiral spring 6 and urged to the lock phase side by the spiral spring 6, and the second arm projection portion 4e abuts on the outermost peripheral portion of the spiral spring 6.

However, the first arm projection portion 4d and the second arm projection portion 4e are not limited to the above configuration. For example, the first rotational phase side in the valve timing adjustment device 100 may be the advance side, and the second rotational phase side may be the retard side. Then, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the advance side, the first arm projection portion 4d may be caught by the terminal hook portion 6b of the spiral spring 6 and urged to the lock phase side by the spiral spring 6, and the second arm projection portion 4e may abut on the outermost peripheral portion of the spiral spring 6. In addition, the second arm projection portion 4e may be configured to be separated from the outermost periphery of the spiral spring 6 when the rotational phase is on the retard side. Further, when the rotational phase is on the retard side, the first plate projection portion 1d may abut on the outermost peripheral portion of the spiral spring 6.

As described above, the valve timing adjustment device 100 according to the first embodiment is the valve timing adjustment device 100, including: a first rotating body that rotates synchronously with a crankshaft; and a second rotating body that rotates synchronously with a camshaft, in which the first rotating body includes a plate 1 having an opening portion 1a around a rotation axis R, the second rotating body includes: a main body portion 4a that passes through the opening portion 1a of the plate 1 and is disposed around the rotation axis R; and a holder 4 having a first arm 4b and a second arm 4c that each extends to an outer peripheral side from an end portion of a portion of the main body portion 4a projecting from the front surface of the plate 1, a spiral spring 6 is installed between the front surface of the plate 1 and the first arm 4b and the second arm 4c, in which the spiral spring 6 is wound around the main body portion 4a, an inner peripheral side end portion is held by the plate 1, and a terminal hook portion 6b is formed by bending an outer peripheral side end portion toward an outer peripheral side, a first arm projection portion 4d is caught by the terminal hook portion 6b of the spiral spring 6, is urged toward a lock phase side by the spiral spring 6 and is installed on a face opposite to the front surface of the plate 1 in the first arm 4b in a case where a rotational phase of the second rotating body with respect to the first rotating body is on a first rotational phase side, and a second arm projection portion 4e abuts on an outermost peripheral portion of the spiral spring 6 and is installed on a face opposite to the front surface of the plate 1 in the second arm 4c in a case where the rotational phase is on the first rotational phase side.

According to the above configuration, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the second rotating body is urged toward the lock phase side by the spiral spring 6 via the first arm projection portion 4d, and the second arm projection portion 4e abuts on the outermost peripheral portion of the spiral spring. As a result, the vibration of the engine transmitted to the spiral spring 6 through the terminal hook catching portion 1c is transmitted from the portion in contact with the terminal hook catching portion 1c to the portion in contact with the second arm projection portion 4e on the outermost periphery of the spiral spring 6, but is hardly transmitted beyond the latter portion. Therefore, resonance of the spiral spring due to vibration of the engine during operation can be suppressed.

Furthermore, according to the above configuration, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the lock phase to the first rotational phase side, the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6 both move to the first rotational phase side in a state of being in contact with each other. In addition, in the process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the first rotational phase side to the lock phase, the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6 are separated from each other while both moving to the lock phase side.

Thus, friction hardly occurs between the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6, so that it is possible to suppress hysteresis generated between a process in which the rotational phase of the second rotating body with respect to the first rotating body changes from the lock position to the first rotational phase side and a process in which the rotational phase changes from the first rotational phase side to the lock position.

Moreover, the second arm projection portion 4e in the valve timing adjustment device 100 according to the first embodiment is configured to be separated from the outermost periphery of the spiral spring 6 in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side.

Therefore, according to the above configuration, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side, friction is less likely to occur between the second arm projection portion 4e and the outermost peripheral portion of the spiral spring 6.

Furthermore, on the front surface of the plate 1 in the valve timing adjustment device 100 according to the first embodiment, the first plate projection portion 1d in contact with the outermost peripheral portion of the spiral spring 6 is installed in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side.

According to the above configuration, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the second rotational phase side, the outermost periphery of the spiral spring 6 abuts on the first plate projection portion 1d, thereby the vibration of the engine transmitted to the spiral spring 6 via the terminal hook catching portion 1c is transmitted from the portion in contact with the terminal hook catching portion 1c at the outermost periphery of the spiral spring 6 to the portion in contact with the first plate projection portion 1d, but is hardly transmitted beyond the latter portion. Therefore, resonance of the spiral spring due to vibration of the engine during operation can be further suppressed.

Furthermore, on the front surface of the plate 1 in the valve timing adjustment device 100 according to the first embodiment, the second plate projection portion 1e in contact with the innermost peripheral portion of the spiral spring 6 is installed.

According to the above configuration, when the spiral spring 6 is wound around the main body portion 4a of the holder 4, the second plate projection portion 1e serves as a guide. Furthermore, the vibration of the engine transmitted to the spiral spring 6 through the starting end hook catching portion 1b is transmitted from the portion in contact with the starting end hook catching portion 1b to the portion in contact with the second plate projection portion 1e on the innermost periphery of the spiral spring 6, but is hardly transmitted beyond the latter portion.

In a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the second arm projection portion 4e in the valve timing adjustment device 100 according to the first embodiment is located on the opposite side to the second plate projection portion 1e side with reference to the rotation axis R.

According to the above configuration, the second arm projection portion 4e becomes an obstacle, and the spiral spring 6 is less likely to move to the side opposite to the second plate projection portion 1e side with reference to the rotation axis R, the portion abutting on the second plate projection portion 1e and the portion on the outer peripheral side corresponding to the portion are less likely to come into contact with each other, and friction is less likely to occur.

On the front surface of the plate 1 in the valve timing adjustment device 100 according to the first embodiment, the second plate projection portion 1e in contact with the innermost peripheral portion of the spiral spring 6 is installed, and on the front surface of the plate 1 opposite to the second plate projection portion 1e with reference to the rotation axis R, the first plate projection portion 1d in contact with the outermost peripheral portion of the spiral spring 6 is installed when the rotational phase is on the second rotational phase side.

According to the above configuration, the first plate projection portion 1d becomes an obstacle, the spiral spring 6 is less likely to move to the side opposite to the second plate projection portion 1e side with respect to the rotation axis R, and the portion abutting on the second plate projection portion 1e and the portion on the outer peripheral side corresponding to the portion are less likely to come into contact with each other, so that friction is less likely to occur.

Moreover, the second arm projection portion 10a of the valve timing adjustment device 100 according to the first embodiment is provided with a spring that urges the second arm projection portion 10a toward the rotation axis R in a case where the second arm projection portion 10a abuts on the outermost peripheral portion of the spiral spring 6 and is pushed toward the outer peripheral side.

According to the above configuration, it is possible to suitably implement a configuration in which the second arm projection portion 10a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side when the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, and a configuration in which the second arm projection portion 10a does not urge the outermost peripheral portion of the spiral spring 6 when the rotational phase is on the second rotational phase side. In short, when the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the second arm projection portion 10a abuts on the outermost peripheral portion of the spiral spring, and it is possible to suppress resonance of the spiral spring due to vibration of the engine during operation. On the other hand, when the rotational phase is on the second rotational phase side, friction is less likely to occur between the second arm projection portion 10a and the outermost peripheral portion of the spiral spring 6.

In addition, the spring installed in the second arm projection portion 10a in the valve timing adjustment device 100 according to the first embodiment is the unequal pitch spring 11.

According to above configuration, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the force by which the second arm projection portion 10a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side can be increased, and in a case where the rotational phase is on the second rotational phase side, the force by which the second arm projection portion 10a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side can be decreased. Therefore, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the second arm projection portion 10a can suppress resonance of the spiral spring due to vibration of the engine during operation, and in a case where the rotational phase is on the second rotational phase side, friction is less likely to occur between the second arm projection portion 10a and the outermost peripheral portion of the spiral spring 6.

Moreover, the first plate projection portion 12a of the valve timing adjustment device 100 according to the first embodiment is provided with a spring that urges the first plate projection portion 12a toward the rotation axis R side when the first plate projection portion 12a abuts on the outermost peripheral portion of the spiral spring 6 and is pushed toward the outer peripheral side.

According to the above configuration, it is possible to suitably implement a configuration in which the first plate projection portion 12a does not urge the outermost peripheral portion of the spiral spring 6 when the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, and a configuration in which the first plate projection portion 12a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side in a case where the rotational phase is on the second rotational phase side. Therefore, when the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, friction is less likely to occur between the first plate projection portion 12a and the outermost peripheral portion of the spiral spring 6. On the other hand, when the rotational phase is on the second rotational phase side, the first plate projection portion 12a abuts on the outermost peripheral portion of the spiral spring, and it is possible to suppress resonance of the spiral spring due to vibration of the engine during operation.

Furthermore, in the valve timing adjustment device 100 according to the first embodiment, the spring installed in the first plate projection portion 12a is the unequal pitch spring 13.

According to above configuration, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, the force by which the first plate projection portion 12a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side can be decreased, and in a case where the rotational phase is on the second rotational phase side, the force by which the first plate projection portion 12a urges the outermost peripheral portion of the spiral spring 6 toward the rotation axis R side can be increased. Accordingly, in a case where the rotational phase of the second rotating body with respect to the first rotating body is on the first rotational phase side, friction is less likely to occur between the first plate projection portion 12a and the outermost peripheral portion of the spiral spring 6, and in a case where the rotational phase is on the second rotational phase side, the first plate projection portion 12a can suppress resonance of the spiral spring due to vibration of the engine during operation.

In addition, the outer peripheral side end portion of the terminal hook portion 14a of the spiral spring 14 in the valve timing adjustment device 100 according to the first embodiment is bent by an angle larger than 90 degrees toward the outer peripheral side.

According to the above configuration, the terminal hook portion 14a is pushed toward the first rotational phase side by the first arm projection portion 4d, and at the same time, slides toward the outer peripheral side with respect to the first arm projection portion 4d. As a result, the outermost peripheral portion of the spiral spring 14 is deformed by being pulled in the direction in which the terminal hook portion 6b slides toward the outer peripheral side, and is separated from first plate projection portion 1d. This eliminates friction between the outermost peripheral portion of spiral spring 6 and first plate projection portion 1d.

Note that, in the present invention, any component of the embodiment can be modified or any component of the embodiment can be omitted within the scope of the invention.

INDUSTRIAL APPLICABILITY

The valve timing adjustment device according to the present invention can suppress resonance of the spiral spring due to vibration of the engine during operation, and thus can be used for the valve timing adjustment device.

REFERENCE SIGNS LIST

- 1: plate, 1a: opening portion, 1b: starting end hook catching portion, 1c: terminal hook catching portion, 1d: first plate projection portion, 1e: second plate projection portion, 2: case, 2a: chain sprocket portion, 3: rotor, 4: holder, 4a: main body portion, 4b: first arm, 4c: second arm, 4d: first arm projection portion, 4e: second arm projection portion, 5: center bolt, 6: spiral spring, 6a: starting end hook portion, 6b: terminal hook portion, 10: holder, 10a: second arm projection portion, 10b: second arm, 10c: through hole, 11: unequal pitch spring, 12: plate, 12a: first plate projection portion, 12b: recess portion, 13: unequal pitch spring, 14: spiral spring, 14a: terminal hook portion, 14b: first portion, 14c: second portion, 100: valve timing adjustment device

VALVE TIMING ADJUSTMENT DEVICE

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CPC

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