JP5535801B2 - Valve timing change device - Google Patents

Description

  The present invention relates to a valve timing changing device that changes the opening / closing timing (valve timing) of an intake valve or an exhaust valve of an internal combustion engine in accordance with an operating situation, and in particular, a vane type valve using fluid pressure such as hydraulic pressure as a driving force. The present invention relates to a timing change device.

  As a conventional valve timing changing device, a sprocket and a housing rotor (shoe housing) that rotate in synchronization with a crankshaft, a rotation that synchronizes with a camshaft, and that is accommodated in the housing rotor, and the accommodating chamber is a retarded angle chamber. A vane rotor that can be divided into an advance angle chamber and rotate relative to the housing rotor in a predetermined angle range (between the most advanced position and the most retarded position), and the vane rotor with respect to the housing rotor when the engine is started Restraint means that restrains the intermediate position between the most retarded angle position and the most advanced angle position (the stopper pin provided on the vane rotor, the fitting ring provided on the housing rotor to fit the stopper pin, and the stopper pin Spring that biases to fit into the fitting ring), and the vane rotor faces the advance side with respect to the housing rotor. And a hydraulic oil control valve (switching valve) that controls the supply and discharge of hydraulic oil to and from the advance and retard chambers. The vane rotor is rotated to the advanced angle side by the biasing force of the advance spring and positioned at the intermediate position by the restraining means, while the vane rotor is intermediate to the housing rotor. When the vehicle is stopped at the advance side of the position, the vane rotor is rotated to the retard side by the fluctuation torque of the engine that normally acts in the retard direction, and is positioned at the intermediate position by the restraining means, thereby improving the startability of the engine. There is known one that can prevent the generation of a hitting sound at the time of starting (for example, see Patent Document 1).

However, in this apparatus, since the urging force of the advance angle spring that urges the vane rotor toward the advance angle side (intermediate position) with respect to the housing rotor is constantly acting, the phase (angle) of the vane rotor is controlled by oil pressure. When controlling the position), it is necessary to control with a hydraulic pressure that overcomes the urging force of the advance spring.
Further, when starting the engine at a low temperature, the hydraulic oil becomes highly viscous and the resistance force increases. Therefore, it is necessary to set the urging force of the advance spring strongly in advance.
Furthermore, if the hydraulic oil has a high viscosity when starting the engine at a low temperature, it may be difficult to smoothly move the vane rotor from the advance side to the retard side due to the fluctuation torque of the engine and move it smoothly to the intermediate position. There is also.

JP 2000-345816 A

  The present invention has been made in view of the above circumstances, and its object is to achieve phase control (advancement of the vane rotor) while simplifying the structure, reducing the number of parts, downsizing the entire apparatus, and the like. Phase change to the angle side or retard angle side), it is possible to smoothly control the phase by preventing an extra load such as a conventional advance spring, and startability of the engine at a low temperature. It is another object of the present invention to provide a valve timing changing device that can improve the noise and prevent the occurrence of a hitting sound or the like when starting the engine.

A valve timing changing device according to the present invention includes a housing rotor that rotates on the axis of a camshaft in conjunction with rotation of a crankshaft, and a housing chamber that is relatively rotatably accommodated in a housing space of the housing rotor within a predetermined angle range. The vane rotor that bisects the advance chamber and retard chamber and rotates integrally with the camshaft, the advance passage that communicates with the advance chamber and allows fluid to pass, and the retard that communicates with the retard chamber and allows fluid to pass A passage, a fluid control valve that controls the flow of fluid in the advance passage and the retard passage, and a positioning mechanism that positions the vane rotor at a predetermined intermediate position within the predetermined angle range with respect to the housing rotor when the engine is started. A valve timing changing device that changes the opening and closing timing of an intake valve or an exhaust valve that is driven to open and close by a camshaft, The positioning mechanism has a balance passage through which fluid can be supplied to or discharged from the advance chamber and the retard chamber in order to balance the vane rotor to an intermediate position when the engine is started, and fluid flows through the balance passage only when the engine is started. Thus, a switching valve for switching the opening and closing of the balance passage is included.
According to this structure, when the engine is started (cranking), when the balance passage is opened by the switching valve and the vane rotor is on the retard side with respect to the intermediate position, fluid flows into the advance chamber through the balance passage. On the other hand, when the vane rotor is on the advance side of the intermediate position, the fluid flows into the retard chamber through the balance passage and is discharged from the advance chamber so that the vane rotor is in the middle. Balanced to a position (positioned at an intermediate position). As a result, the engine can be started (completely exploded) smoothly (even at low temperatures) without the occurrence of a hitting sound or the like and without a load caused by a spring force as in the prior art. Even after the engine is started (complete explosion), it is possible to prevent the excessive load from being applied and to smoothly perform the phase control. Moreover, since the balance passage and the switching valve are adopted as the positioning mechanism, it is possible to cope with the problem by forming a passage with respect to the conventional structural parts and arranging the switching valve in the passage. It is unnecessary, and simplification of the structure, reduction of the number of parts, miniaturization of the entire apparatus, etc. can be achieved.

In the above configuration, the balance passage communicates with the advance chamber when the vane rotor deviates from the intermediate position to the retard side, and supplies fluid by communicating with the retard chamber when the vane rotor deviates from the intermediate position to the advance side. A balance passage and a discharge balance passage that communicates with the retard chamber when the vane rotor deviates from the intermediate position to the retard side and communicates with the advance chamber when the vane rotor deviates from the intermediate position to the advance side The configuration can be adopted.
According to this configuration, when the vane rotor is retarded from the intermediate position at the time of engine start (during cranking), fluid flows into the advance chamber through the supply balance passage and retards through the discharge balance passage. When the fluid is discharged from the chamber and the vane rotor is on the more advanced side than the intermediate position, the fluid flows into the retarded chamber through the supply balance passage, and the fluid is discharged from the advance chamber through the discharge balance passage. The vane rotor is balanced at the intermediate position (positioned at the intermediate position). Here, the communication operation between the supply balance passage and the advance chamber or the retard chamber and the communication operation between the discharge balance passage and the advance chamber or the retard chamber are performed only by relative rotation of the vane rotor and the housing rotor. Therefore, functional reliability can be ensured while achieving simplification of the structure.

In the above configuration, the switching valve is provided so as to bisect the advance passage and the retard passage into the upstream advance passage, the downstream advance passage, the upstream retard passage, and the downstream retard passage, respectively. A rest position in which the passage and the discharge balance passage are communicated with one and the other of the upstream advance passage and the upstream retard passage, and the downstream advance passage and the downstream retard passage are blocked, the supply balance passage and the discharge balance. It is possible to adopt a configuration that is configured so as to be selectively switched to any position of the operation position that blocks the passage and opens the advance passage and the retard passage.
According to this configuration, when the engine is started (cranking), the switching valve is positioned at the rest position, and the supply balance passage communicates with one of the upstream advance passage and the upstream retard passage, and the upstream A discharge balance passage communicates with the other of the side advance passage and the upstream retard passage, and supply and discharge of fluid for balancing the vane rotor to the intermediate position becomes possible. On the other hand, after the engine is started (complete explosion), the switching valve is located at the operating position, shuts off the supply balance passage and the discharge balance passage, and advances the advance passage (upstream advance passage and downstream advance passage) and Since the retarding passages (the upstream retarding passage and the downstream retarding passage) are opened so as to allow the flow of fluid, the normal phase changing operation can be reliably performed without being affected by the vanance passage. .

In the above configuration, the switching valve is positioned at the rest position by the biasing force of the spring, and is configured to be switched from the rest position to the operating position while resisting the biasing force of the spring by receiving the fluid pressure generated by the control of the fluid control valve. It is possible to adopt the configuration.
According to this configuration, the switching valve is biased by the spring and positioned at the rest position, and is switched to the operating position by receiving fluid pressure by the control operation of the fluid control valve. Therefore, when the engine is started, the switching valve is The vane rotor can be immediately balanced to the intermediate position without moving (switching).

In the above configuration, the switching valve includes a first pressure receiving portion that receives the pressure of the fluid guided through the upstream side advance passage, and a second pressure receiving portion that receives the pressure of the fluid guided through the upstream side retard passage. It is possible to adopt a configuration in which at least one of the first pressure receiving portion and the second pressure receiving portion is configured to be switched from the rest position to the operating position while resisting the biasing force of the spring.
According to this configuration, the switching valve remains in the rest position unless the fluid pressure is applied to the first pressure receiving portion or the second pressure receiving portion, and is controlled by the fluid control valve after engine start (complete explosion). When the fluid pressure is applied to at least one of the first pressure receiving portion and the second pressure receiving portion, the switching valve is switched to the operating position so that the normal phase changing operation can be performed in a state where the influence of the balance passage is eliminated. become. In particular, by switching the switching valve using the pressure of the fluid, the switching operation of the switching valve can be performed using a fluid control valve that controls the flow of the fluid without requiring a dedicated drive source. .

In the above configuration, the piston valve includes a center bolt for fastening the vane rotor to the cam shaft on the axis of the cam shaft, and the switching valve is reciprocally accommodated in an accommodation passage formed in the axial direction with respect to the center bolt. The center bolt and the switching valve can adopt a configuration in which at least a part of each of the advance passage, the retard passage, the supply balance passage, and the discharge balance passage is defined.
According to this configuration, a center passage that has been conventionally used is provided with a storage passage, and a piston valve as a switching valve is arranged in the storage passage, so that the parts are consolidated and the moment of inertia around the camshaft axis is obtained. And the influence of centrifugal force on the switching valve can be prevented.

The above configuration includes a lock mechanism that locks the vane rotor at an intermediate position when the engine is started. The lock mechanism is provided on the housing rotor and is engaged with the lock cam by an urging force provided on the housing rotor. A configuration including a lock bar that can be locked and released by fluid pressure can be employed.
According to this configuration, when the engine is started (cranking), the lock bar locks the lock cam so that the vane rotor is locked at an intermediate position with respect to the housing rotor. The lock by the lock bar can be released by the pressure. Therefore, in addition to the positioning operation by the positioning mechanism, the vane rotor can be reliably maintained at the intermediate position by the lock mechanism, and the engine can be started more reliably. Further, since the vane rotor is not directly locked, the vane portion of the vane rotor can be thinned, and the degree of freedom in design and layout is increased.

The above configuration further includes a biasing spring that biases the lock bar so as to engage and lock the lock cam, and the lock bar is advanced to engage the lock cam so as to restrict the vane rotor from rotating to the advance side. An angle regulation lock bar and a retard angle regulation lock bar that engages the lock cam to regulate the rotation of the vane rotor to the retard angle side, and the urging spring locks the advance angle regulation lock bar by engaging the lock cam. Including a lead angle regulating urging spring that urges the lagging force and a retard angle regulating urging spring that urges the lag angle regulating lock bar to engage and lock the lock cam. In the position, the advance angle restricting side communication passage that leads the fluid pressure to the advance angle restricting lock bar and the retard angle chamber or the retard angle passage communicate with the advance angle chamber or the advance angle passage to release the lock. And rock Leading to retard limiting lock bar the pressure of the fluid in order to release the containing retard limiting side communication path, it is possible to adopt a configuration.
According to this configuration, when the engine is started (at the time of cranking), the advance angle restricting lock bar has an advance angle restricting state in a state in which no fluid pressure is applied to the advance angle restricting side communication path and the retard angle restricting side communication path. The lock cam (that is, the vane rotor) is biased by the bias spring to restrict the shift cam from the intermediate position to the advance side, and the retard angle control lock bar is biased by the retard angle control bias spring and the lock cam (that is, the vane rotor) is intermediate. The vane rotor is reliably positioned at the intermediate position in order to restrict the shift from the position to the retard side. On the other hand, after starting the engine (complete explosion), with the switching valve in the operating position, the advance angle restricting lock bar and the retard angle restricting lock bar are passed through the advance angle restricting side communication path and the retard angle restricting side communication path. On the other hand, fluid pressure is applied, and the lock by the advance angle restricting lock bar is released so as not to hinder the advance angle operation, and the lock by the retard angle restricting lock bar is released so as not to hinder the retard angle operation.

In the above-described configuration, a configuration can be adopted in which the lock bar is swingably supported in a vertical plane perpendicular to the axis of the camshaft.
According to this configuration, when the engine is stopped, even when the lock bar (advance angle regulation lock bar, retard angle regulation lock bar) is out of the position where the lock cam is locked, the engine is started (during cranking). The lock cam (that is, the vane rotor) can be reliably locked at the intermediate position by rotating the lock bar in the direction in which the lock bar is biased by the torque fluctuation of the cam shaft.

  According to the valve timing changing device having the above-described configuration, the vane rotor phase control (advance angle) can be achieved by preventing the additional load while achieving the simplification of the structure, the reduction in the number of parts, the miniaturization of the entire device, and the like. (Changing the phase to the side or retarded angle) can be carried out smoothly, the engine startability at low temperatures can be improved, and the occurrence of noise and the like at engine start can also be prevented. .

It is a disassembled perspective view which shows one Embodiment of the valve timing change apparatus which concerns on this invention. It is sectional drawing which shows the inside of the valve timing change apparatus at the time of engine starting. It is sectional drawing which shows the inside of the valve timing change apparatus after engine starting. It is sectional drawing which shows the state which has a vane rotor in an intermediate position at the time of engine starting. It is sectional drawing which shows the state which has a vane rotor in the most retarded angle position at the time of engine starting. It is sectional drawing which shows the state which has a vane rotor in the most advanced angle position at the time of engine starting. FIG. 7 is a cross-sectional view showing a relationship between the vane rotor and the housing rotor, and showing a downstream side advance passage communicating with the advance chamber in a state where the vane rotor moves to the retard side. FIG. 5 is a cross-sectional view showing a relationship between a vane rotor and a housing rotor, and showing a downstream side retard passage that communicates with a retard chamber while the vane rotor moves to the retard side. It is sectional drawing which shows the state which locked the vane rotor to the housing rotor at the time of engine starting (lock bar locked the lock cam). It is sectional drawing which shows the state of the lock mechanism (lock bar) at the time of changing a phase to the most retarded angle position after starting of an engine. It is sectional drawing which shows the state of the lock mechanism (lock bar) at the time of changing a phase to the most advanced angle position after starting of an engine. It is a mimetic diagram of a valve timing change device at the time of starting of an engine. It is a schematic diagram explaining operation | movement of the positioning mechanism at the time of engine start, (a) supplies a fluid to an advance chamber and discharges a fluid from a retard chamber when a vane rotor shifts | deviates from the intermediate position to a retard angle side. FIG. 5B is a schematic diagram showing a state in which fluid is supplied to the retarding chamber and fluid is discharged from the advance chamber when the vane rotor is shifted from the intermediate position to the advance side. It is a schematic diagram explaining operation | movement of the valve timing change apparatus in the case of changing a phase to a retard side after an engine start. It is a schematic diagram explaining operation | movement of the valve timing change apparatus in the case of changing a phase to an advance angle side after engine starting. It is a schematic diagram explaining operation | movement of the valve timing change apparatus in the case of hold | maintaining to a predetermined phase after starting of an engine.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in FIGS. 1 to 3, the valve timing changing device rotates on a vane rotor 20 that can be detachably fixed to the camshaft 10, the axis S <b> 1 of the camshaft 10, and can relatively rotate the vane rotor 20. Housing rotor 30 (housing member 31, sprocket member 32, cover member 33) that accommodates and cooperates with vane rotor 20 to define advance chamber 30 a and retard chamber 30 b, lock cam 40 fixed to vane rotor 20, housing rotor 30, the advance angle restriction lock bar 50 and the advance angle restriction urging spring 51 for restricting the vane rotor 20 (lock cam 40) from moving toward the advance side, and the vane rotor 20 (lock cam 40) provided on the housing rotor 30. Retardation regulating lock bar 60 and retarding regulation that regulates shifting to the retarded side A biasing spring 61, a center bolt 70 for fastening the vane rotor 20 to the camshaft 10, a switching valve 80, a biasing spring 90, and a biasing spring constituting a part of a positioning mechanism that is reciprocally disposed inside the center bolt 70. A cap 100 covering 90, a hydraulic oil control valve (OCV) 113 as a fluid control valve for controlling the flow of hydraulic oil (engine lubricating oil) as a fluid, and a hydraulic oil control system 110 including a hydraulic oil passage. I have.

The camshaft 10 opens and closes an intake valve or an exhaust valve of an engine by a cam action, and the housing rotor 30 is interlocked with the rotation of the crankshaft via a chain or the like, and the rotational driving force of the crankshaft. Is transmitted to the camshaft 10 via the vane rotor 20.
Further, the lock cam 40, the advance angle restricting lock bar 50, the advance angle restricting urging spring 51, the retard angle restricting lock bar 60, and the retard angle restricting urging spring 61 allow the vane rotor 20 to be moved relative to the housing rotor 30 when the engine is started. Thus, a locking mechanism is configured to lock at a predetermined intermediate position within a predetermined angular range that can be relatively rotated.
In this device, the predetermined angle range (angle range from the most retarded angle position to the most advanced angle position) is set to approximately 37 degrees, and the intermediate position is rotated about 10 degrees from the most retarded angle position to the advanced angle side. The angular position is set.

  The camshaft 10 is supported by a bearing B formed on the cylinder head of the engine so as to be rotatable about an axis S1 (so as to rotate in the direction of arrow CR in FIG. 1). As shown in FIGS. 4 to 6, the journal portion 11 supported by the bearing B, the cylindrical portion 12 that rotatably supports the housing rotor 30, the upstream side advance passage 13 that is formed inside and passes the hydraulic oil, and the upstream side A side retardation passage 14, a supply balance passage 15 for supplying hydraulic oil, a discharge balance passage 16 for discharging hydraulic oil, a female screw portion 17 for fastening a center bolt 70, and the like are provided.

The upstream side advance passage 13 communicates with the advance chamber 30a in order to introduce the hydraulic oil into the advance chamber 30a or to discharge the hydraulic oil from the advance chamber 30a in accordance with the control of the hydraulic oil control valve 113. Is formed.
The upstream retarding passage 14 communicates with the retarding chamber 30b in order to introduce the working oil into the retarding chamber 30b or to discharge the working oil from the retarding chamber 30b according to the control of the working oil control valve 113. Is formed.
The supply balance passage 15 is closed by the housing rotor 30 (the inner peripheral surface 32b of the sprocket member 32) when the vane rotor 20 is located at the intermediate position as shown in FIG. 4, and the vane rotor 20 is closed as shown in FIG. When deviating to the retard side (through the groove passage 32c of the sprocket member 32), it communicates with the advance chamber 30a, and when the vane rotor 20 deviates to the advance side as shown in FIG. 6 (through the groove passage 32e of the sprocket member 32). ) It is formed to communicate with the retard chamber 30b.
The discharge balance passage 16 is closed by the housing rotor 30 (the inner peripheral surface 32b of the sprocket member 32) when the vane rotor 20 is located at the intermediate position as shown in FIG. 4, and the vane rotor 20 is closed as shown in FIG. When it deviates to the retard side (through the groove passage 32d of the sprocket member 32), it communicates with the retard chamber 30b, and when the vane rotor 20 deviates to the advance side as shown in FIG. 6 (through the groove passage 32c of the sprocket member 32). ) It is formed to communicate with the advance chamber 30a.

The supply balance passage 15 and the discharge balance passage 16 can supply or discharge fluid (hydraulic oil) to the advance chamber 30a and the retard chamber 30b so as to balance the vane rotor 20 to an intermediate position when the engine is started. And forms part of a positioning mechanism for positioning the vane rotor 20 at the intermediate position.
Although the case where the supply balance passage 15 and the discharge balance passage 16 are provided in the camshaft 10 has been described here, the present invention is not limited to this and may be provided in the vane rotor 20.

As shown in FIGS. 1 to 3, 7, and 8, the vane rotor 20 is formed in four hub parts 21, a hub part 22 that integrally holds the four vane parts 21 at equal intervals, and a hub part 22. A through hole 23 through which the center bolt 70 is passed, a downstream advance passage 24 communicating with the advance chamber 30a, a downstream retard passage 25 communicating with the retard chamber 30b, and a tip of the vane portion 21 are formed at the tip of the vane portion 21. Four groove portions 26 into which S is fitted, an arcuate groove passage 27 formed on the front surface of the hub portion 22 so as to communicate with an advance angle restricting communication passage 31f described later, and a retard angle restricting communication passage 31g described later communicate with each other. Accordingly, an arcuate groove passage 28 formed on the front surface of the hub portion 22 is provided.
As shown in FIG. 2, the vane rotor 20 is fastened to the camshaft 10 together with the lock cam 40 by using a center bolt 70 and rotates integrally with the camshaft 10.

The housing rotor 30 is rotatably supported on the axis S1 of the camshaft 10 in conjunction with the rotation of the crankshaft. As shown in FIGS. 4 to 8, the vane rotor 20 is relatively moved within a predetermined angle range. The storage chamber is defined in such a manner that the storage chamber is divided into an advance chamber 30a and a retard chamber 30b by the vane rotor 20 (the vane portion 21).
That is, the housing rotor 30, as shown in FIGS. 1 to 3, defines a housing chamber that houses the vane rotor 20 on the back surface side and a housing member 31 that defines a housing chamber (concave portion) that houses the lock mechanism on the front surface side. The sprocket member 32 is rotatably fitted to the cylindrical portion 12 of the camshaft 10 and is coupled to the back surface of the housing member 21, and the cover member 33 is coupled to the front surface of the housing member 31.

  As shown in FIGS. 1 to 3 and 7 to 11, the housing member 31 includes an annular wall 31a, a through hole 31b, and four bearing portions 31c that protrude toward the center on the back side of the annular wall 31a. A fan-shaped accommodation chamber 31d defined between the bearing portions 31c, a recess 31e formed on the front side of the annular wall 31a to accommodate the lock mechanism, an advance restriction regulating communication path 31f, a retard regulation regulating communication path 31g, a support Shafts 31h, 31i, latching protrusions 31j, 31k, stopper wall 31m for defining the most retarded angle position, stopper wall 31n for defining the most advanced angle position, stopper wall 31o with which the advance angle regulating lock bar 50 can come into contact, retard angle A stopper wall 31p or the like on which the restriction lock bar 60 can come into contact is provided.

As shown in FIGS. 9 to 11, the recess 31 e has an advance restriction biasing spring 51 so that the lock cam 40 can be rotated around the axis S 1 and the advance restriction lock bar 50 can be swung around the axis S 2. The retard angle restricting lock bar 60 is configured to be retractable and swingable about the axis S <b> 3, and the retard angle restricting biasing spring 61 is configured to be retractable.
The recess 31e cooperates with the side surface of the advance angle restricting lock bar 50 so as to fill the hydraulic oil guided from the advance angle restricting side communication passage 31f to obtain a hydraulic pressure of a predetermined level or more. In cooperation with the side surface of the angle restriction lock bar 60, the hydraulic oil guided from the retard angle restriction communication path 31g is filled to obtain a hydraulic pressure of a predetermined level or higher.
The advance angle restricting side communication passage 31f communicates with the advance angle chamber 30a and the downstream advance angle passage 24 in order to release the lock by the advance angle restricting lock bar 50 against the urging force of the advance angle restricting spring 51. Thus, the hydraulic pressure is guided to the side surface of the advance restriction lock bar 50.
The retard restriction communication passage 31g communicates with the retard chamber 30b and the downstream retard passage 25 in order to release the lock by the retard restriction lock bar 60 against the urging force of the retard restriction urging spring 61. Thus, the hydraulic pressure is guided to the side surface of the retard restriction lock bar 60.

As shown in FIGS. 9 to 11, the support shaft 31 h is formed so as to swingably support the advance angle regulating lock bar 50 in a vertical plane perpendicular to the axis S <b> 1.
As shown in FIGS. 9 to 11, the support shaft 31i is formed so as to swingably support the retard restriction lock bar 60 within a vertical plane perpendicular to the axis S1.
As shown in FIGS. 9 to 11, the latching protrusion 31 j is formed to latch one end of the advance angle regulating urging spring 51.
As shown in FIGS. 9 to 11, the latching protrusion 31 k is formed so as to latch one end of the retard restriction urging spring 61.
The stopper wall 31m defines the most retarded angle position by bringing the protrusion 41 of the lock cam 40 into contact with the vane rotor 20 within a predetermined angle range in which the vane rotor 20 rotates relative to the housing rotor 30 as shown in FIG. is there.
The stopper wall 31n defines the most advanced angle position by bringing the protrusion 41 of the lock cam 40 into contact with the vane rotor 20 within a predetermined angle range in which the vane rotor 20 rotates relative to the housing rotor 30 as shown in FIG. is there.
As shown in FIGS. 9 and 10, the stopper wall 31 o is a rest that can lock the lock cam 40 when the advance angle regulating lock bar 50 is rotated and energized by the energizing force of the advance angle regulating energizing spring 51 without applying hydraulic pressure. It defines the position.
As shown in FIGS. 9 and 10, the stopper wall 31 p is a rest that can lock the lock cam 40 by the urging force of the retard restriction urging spring 61 without being applied with the hydraulic pressure and the urging force of the retard restriction urging spring 61. It defines the position.

As shown in FIGS. 1 to 6, the sprocket member 32 is rotatably fitted to a sprocket 32 a around which a chain for transmitting the rotational driving force of the crankshaft is wound and the cylindrical portion 12 of the camshaft 10. The peripheral surface 32b, groove passages 32c, 32d, 32e formed on the front surface where the rear surface of the vane rotor 20 is slidably contacted, screw holes for coupling to the housing member 31 using bolts, and the like are provided.
The groove passage 32c is disconnected from the supply balance passage 15 and the discharge balance passage 16 when the camshaft 10 (vane rotor 20) is at an intermediate position with respect to the sprocket member 32 as shown in FIG. Thus, when the camshaft 10 (vane rotor 20) deviates from the intermediate position to the retard side, the hydraulic oil is guided into the advance chamber 30a in communication with the supply balance passage 15, and as shown in FIG. When 20) deviates from the intermediate position to the advance side, the hydraulic fluid can be discharged from the advance chamber 30a in communication with the discharge balance passage 16.
The groove passage 32d is a supply balance passage when the camshaft 10 (vane rotor 20) is at an intermediate position with respect to the sprocket member 32 as shown in FIG. 4 and at a position deviating from the intermediate position to the advance side as shown in FIG. As shown in FIG. 5, when the camshaft 10 (vane rotor 20) deviates from the intermediate position to the retard side, the hydraulic oil is retarded by communicating with the discharge balance passage 16 as shown in FIG. It is formed so that it can be discharged from the chamber 30b.
The groove passage 32e is a supply balance passage when the camshaft 10 (vane rotor 20) is at an intermediate position with respect to the sprocket member 32 as shown in FIG. 4 and at a position deviating from the intermediate position to the retard side as shown in FIG. When the camshaft 10 (vane rotor 20) deviates from the intermediate position to the advance side as shown in FIG. 6, the hydraulic oil is advanced by communicating with the supply balance passage 15 as shown in FIG. It is formed so as to be led into the chamber 30a.

As shown in FIGS. 1 to 3, the cover member 33 has a circular hole 33 a through which the center bolt 70 passes, and is formed to be detachable from the housing member 31.
In the cover member 33, the lock mechanism (lock cam 40, advance angle restricting lock bar 50, advance angle restricting biasing spring 51, retard angle restricting lock bar 60, retard angle restricting biasing spring 61) is accommodated in the recess 31e. In this state, it is covered from the front and sealed so that the hydraulic oil does not leak, and is coupled to the housing member 31 using bolts or the like.

As shown in FIGS. 1 to 3 and 9 to 11, the lock cam 40 is fastened to the camshaft 10 together with the vane rotor 20 by a center bolt 70, and rotates integrally with the vane rotor 20 and the camshaft 10. The protrusion 41 that can come into contact with the stopper walls 31m, 31n, the cam surface 42 that can be releasably engaged with the advance angle restricting lock bar 50, and the cam surface that can be releasably engaged with the retard angle restricting lock bar 60 43, a through hole 44 through which the center bolt 70 is passed is provided.
The cam surface 42 is formed such that when the vane rotor 20 is in the intermediate position, the advance angle restricting lock bar 50 contacts and the rotation to the advance angle side is restricted.
The cam surface 43 is formed such that when the vane rotor 20 is in the intermediate position, the retard angle regulation lock bar 60 contacts and the rotation to the retard angle side is regulated.
Then, in the state shown in FIG. 9, the lock cam 40 is locked by the advance angle restricting lock bar 50 and the retard angle restricting lock bar 60 and positioned at the intermediate position, and the protrusion 41 abuts against the stopper wall 31m as shown in FIG. In this state, the most retarded angle position is defined, and as shown in FIG. 11, the most advanced angle position is defined on the camshaft 10 so that the projection 41 is in contact with the stopper wall 31n.

As shown in FIGS. 9 to 11, the advance angle regulating lock bar 50 is supported by the support shaft 31h of the housing member 31 and can swing around the axis S2 in a vertical plane perpendicular to the axis S1. The other end of the restriction urging spring 51 is hooked and urged to rotate counterclockwise so as to abut against the stopper wall 31o.
The advance angle restricting lock bar 50 abuts against the cam wall 42 of the lock cam 40 in a state where the counterclockwise rotation is restricted by abutting against the stopper wall 31o, and the lock cam 40 (that is, the vane rotor 20) is moved from the rest position. The rotation to the advance side is restricted, while the lock is released by being rotated clockwise by the hydraulic pressure of the hydraulic fluid supplied through the advance angle restriction side communication passage 31f.

As shown in FIGS. 9 to 11, the retard angle regulation lock bar 60 is supported by the support shaft 31 i of the housing member 31 and can swing around the axis S <b> 3 in a vertical plane perpendicular to the axis S <b> 1. The other end of the restricting biasing spring 61 is hooked and rotated and biased clockwise so as to contact the stopper wall 31p.
Then, the retard restriction lock bar 60 abuts against the cam surface 43 of the lock cam 40 in a state in which clockwise rotation is restricted by contacting the stopper wall 31p, and the lock cam 40 (that is, the vane rotor 20) is delayed from the rest position. Rotation to the angle side is restricted, and on the other hand, the lock is released by being rotated counterclockwise by the hydraulic pressure of the hydraulic oil supplied through the retard restriction side communication passage 31g.
In this way, the lock bars (advance angle regulation lock bar 50, retard angle regulation lock bar 60) are supported in a swingable manner in a vertical plane perpendicular to the axis S1 of the camshaft 10, so that the engine is stopped. Even when the lock bars (advance angle regulation lock bar 50, retard angle regulation lock bar 60) are out of the position where the lock cam 40 is locked, the torque fluctuation of the camshaft 10 at the time of engine start (during cranking) For example, the lock bar (advance angle regulation lock bar 50, retard angle regulation lock bar 60) is rotated in the biased direction, and the lock cam 40 (that is, the vane rotor 20) is reliably moved to the intermediate position to be locked. it can.
Further, since the vane rotor 20 is not directly locked by adopting the above-described locking mechanism, the vane portion 21 of the vane rotor 20 can be thinned, and therefore, the degree of freedom in design and the degree of freedom in layout can be increased.

  As shown in FIGS. 1 to 3, the center bolt 70 fastens the lock cam 40 and the vane rotor 20 to the camshaft 10. The center bolt 70 extends in the direction of the axis S1 so that the switching valve 80 can reciprocate freely. An accommodating passage 71 for accommodating, a stopper wall 72 for defining a rest position of the switching valve 80, an upstream advance passage 73 communicating with the upstream advance passage 13, a supply balance passage 74 communicating with the supply balance passage 15, a downstream advance A downstream advance passage 75 communicating with the angular passage 24, an upstream retard passage 76 communicating with the upstream retard passage 14 and the accommodating passage 71, a discharge balance passage 77 communicating with the discharge balance passage 16, and a downstream retard passage 25, a downstream side retarded passage 78 communicating with 25, a male threaded portion 79 that is screwed into the female threaded portion 17, and the like.

  As shown in FIGS. 1 to 3, the switching valve 80 is a piston valve that slides in the accommodation passage 71 of the center bolt 70 and is reciprocally movable in the direction of the axis S1. The first pressure receiving portion 81, the communication passage 82 extending in the direction of the axis S1, the second pressure receiving portion 83 having a conical surface formed at the end of the communication passage 82, the annular communication passage 84 formed on the outer periphery, and the radial direction. A communication path 85 that is opened, a communication path 86 that is annularly and radially opened on the outer periphery, a spring receiving portion 87, an end portion 88, and the like are provided.

The first pressure receiving portion 81 is formed so as to be able to receive the pressure of the hydraulic fluid guided through the upstream side advance passages 13 and 73.
The communication passage 82 is formed so as to communicate with the upstream retarding passages 14, 76, the communication passage 85, and the communication passage 86.
The second pressure receiving portion 83 is formed so as to be able to receive the pressure of the hydraulic oil guided through the upstream retarding passage 76 and the communication passage 82.
Here, the first pressure receiving portion 81 and the second pressure receiving portion 83 are shown in a state where the switching valve 80 is moved from the rest position shown in FIG. 2 while resisting the urging force of the urging spring 90 by the pressure of the hydraulic oil received by at least one of them. 3 is formed so as to define a pressure receiving area that receives a pressing force enough to be switched to the operation position shown in FIG.
In this embodiment, more specifically, first, when the second pressure receiving portion 83 receives pressure, the switching valve 80 is switched from the rest position to the operating position, and then the first pressure receiving portion 81 is also switched. Even when pressure is applied and pressure is applied to only one of the first pressure receiving portion 81 and the second pressure receiving portion 83, the switching valve 80 is held in the operating position as it is.

The communication passage 84 communicates the upstream advance passage 73 and the supply balance passage 74 when in the rest position shown in FIG. 2, and the upstream advance passage 73 and the downstream side when in the operation position shown in FIG. The advance angle passage 75 is communicated, and the upstream angle advance passage 73 and the supply balance passage 74 are blocked from communicating with each other.
When the communication passage 85 is in the rest position shown in FIG. 2, the discharge balance passage 77 communicates with the communication passage 82 (that is, the upstream retarding passages 14, 76) and is in the operating position shown in FIG. It is formed so that the communication between the discharge balance passage 77 and the communication passage 82 can be blocked.
The communication passage 86 blocks communication between the downstream retard passage 78 and the communication passage 82 (that is, the upstream retard passages 14, 76) when in the rest position shown in FIG. 2, and operates as shown in FIG. When in the position, the downstream side retarding passage 78 and the communication passage 82 (that is, the upstream side retarding passages 14, 76) can be communicated with each other.
As shown in FIGS. 2 and 3, the spring receiving portion 87 is formed to receive one end of the urging spring 90.
As shown in FIGS. 2 and 3, the end portion 88 is formed so as to abut against the cap 100 and define the operating position of the switching valve 80.

That is, the switching valve 80 bisects the advance passage that communicates with the advance chamber 30a into the upstream advance passages 13 and 73 and the downstream advance passages 24 and 75, and the retard passage that communicates with the retard chamber 30b. The upstream retard passages 14 and 76 and the downstream retard passages 25 and 78 are bisected.
When the first pressure receiving portion 81 and the second pressure receiving portion 83 are not subjected to the pressure of the hydraulic oil and are in the rest position shown in FIG. The upstream advance passage 13 is communicated, the discharge balance passage 16 is communicated with the upstream retard passage 14, and the downstream advance passage 24 and the downstream retard passage 25 are blocked.
On the other hand, the switching valve 80 moves to the operating position shown in FIG. 3 against the biasing force of the biasing spring 90 when any one of the first pressure receiving portion 81 and the second pressure receiving portion 83 receives the pressure of the hydraulic oil. Then, the supply balance passage 15 and the discharge balance passage 16 are shut off, and the advance passage and the retard passage are opened, that is, the upstream advance passage 13 and the downstream advance passage 24 are connected to each other, and the upstream retard passage is connected. The passage 14 and the downstream retard passage 25 are communicated with each other.
As described above, the switching valve 80 is positioned at the rest position shown in FIG. 2 by the urging force of the urging spring 90, and the urging force of the urging spring 90 receives the pressure of the hydraulic oil generated by the control of the hydraulic oil control valve 113. 3 is switched from the rest position to the operation position shown in FIG. 3, that is, selectively switched to either the rest position or the operation position.
Here, since the switching valve 80 is disposed in the center bolt 70, the parts can be consolidated to reduce the moment of inertia around the axis S1 of the camshaft 10, and the influence of centrifugal force on the switching valve 80 can be prevented. can do.
Further, since the switching valve 80 can be switched between the rest position and the operating position using the hydraulic oil pressure, a dedicated drive source can be obtained by performing a switching operation using the hydraulic oil control valve 113 that controls the flow of the hydraulic oil. It is not necessary and the structure can be simplified.

As shown in FIGS. 2 and 3, the biasing spring 90 has one end in contact with the spring receiving portion 87 of the switching valve 80 and the other end in contact with the inner wall surface of the cap 100. The urging force is exerted so as to position the switching valve 80 at the rest position.
As shown in FIGS. 2 and 3, the cap 100 is coupled to the center bolt 70 so as to press the other end of the urging spring 90.

As shown in FIGS. 2, 3, 12, and 14 to 16, the hydraulic oil control system 110 includes a pump 111 that feeds hydraulic oil, a drain passage 112, a hydraulic oil control valve (OCV) 113, and an upstream advance angle. A passage 114, an upstream retard passage 115, and the like are provided.
As shown in FIGS. 2 and 3, the hydraulic oil control valve 113 supplies the hydraulic oil to the upstream advance passage 114 and discharges the hydraulic oil from the upstream retard passage 115. DP port 113b capable of supplying hydraulic oil to the angular passage 115 and discharging hydraulic oil from the upstream advance passage 114, PP port 113c capable of supplying hydraulic oil to the upstream advance passage 114 and the upstream retard passage 115 It has.
The hydraulic oil control valve 113 is selected so that the PD port 113a is selected by the biasing force of the spring in a non-energized pause state, and the DP port 113b or the PP port 113c is selected by appropriately controlling the electromagnetic driving force. It has become.
The upstream side advance passage 114 and the upstream side retard passage 115 are pipes for a hydraulic oil passage (lubricating oil passage) formed in the cylinder block or cylinder head of the engine or a hydraulic oil passage disposed outside the engine. Or the like.

Next, the operation of the valve timing changing device will be described with reference to FIGS. 2, 3, 12 to 16.
When the engine is stopped, as shown in FIGS. 2 and 12, the PD port 113a is selected as the hydraulic oil control valve 113, and the switching valve 80 is located at the rest position so as to be balanced with the upstream side advance passages 13 and 114. The passage 15 is in communication and the upstream retard passages 14 and 115 and the discharge balance passage 16 are in communication. Further, the vane rotor 20 is positioned at the rest position shown in FIG. 4 when the advance angle restricting lock bar 50 and the retard angle restricting lock bar 60 are in the locked state (locked state) as shown in FIG. When it is not locked by the advance angle regulating lock bar 50 and the retard angle regulating lock bar 60 (unlocked state), it is stopped at an arbitrary position within a predetermined angle range.

Therefore, when the engine starts (cranking), the vane rotor 20 is relatively rotatable when the engine is unlocked in the state shown in FIGS. 2 and 12.
Here, as shown in FIG. 13A, when the vane rotor 20 is on the retard side with respect to the intermediate position, the hydraulic oil flows into the advance chamber 30 a through the supply balance passage 15 and through the discharge balance passage 16. The hydraulic oil is discharged from the retard chamber 30b.
On the other hand, as shown in FIG. 13B, when the vane rotor 20 is on the more advanced side than the intermediate position, the hydraulic oil flows into the retard chamber 30b through the supply balance passage 15 and advances through the discharge balance passage 16. The hydraulic oil is discharged from the corner chamber 30a.
Further, the advance angle restricting lock bar 50 and the retard angle restricting lock bar 60 cause the lock cam 40 to be intermediate between the balance operation, the torque fluctuation of the camshaft 10, the advance angle restricting bias spring 51, the retard angle restricting spring 61, and the like. Operates to lock into position.

As a result, the vane rotor 20 is immediately balanced at the intermediate position (positioned at the intermediate position), and prevents the occurrence of hitting sound and the like, without the load caused by the spring force as in the conventional case (at low temperatures). Even) can start the engine smoothly (complete explosion). Further, even after the engine is started (complete explosion), it is possible to prevent an excessive load from being applied and to smoothly perform the phase shift control.
In particular, since the balance passage (the supply balance passage 15 and the discharge balance passage 16) and the switching valve 80 are employed as the positioning mechanism, the communication operation and the discharge balance between the supply balance passage 15 and the advance chamber 30a or the retard chamber 30b. The communication operation between the passage 16 and the advance chamber 30a or the retard chamber 30b can be performed only by the relative rotation caused by the torque fluctuation between the vane rotor 20 and the housing rotor 30. It is possible to cope with this by forming a passage and disposing the switching valve 80 in this passage, which eliminates the need for complicated control, simplifies the structure, reduces the number of parts, and reduces the overall size of the device. And functional reliability can be ensured.

When the engine is started (complete explosion), as shown in FIGS. 3 and 14, the hydraulic oil control valve 113 is switched to the DP port 113 b, and the second pressure receiving portion 83 is guided through the upstream retarding passages 115 and 14. Under the pressure of the hydraulic oil, the switching valve 80 moves to the operating position against the biasing force of the biasing spring 90.
Then, the communication between the supply balance passage 15 and the upstream side advance passages 13 and 114 is blocked, and the communication between the discharge balance passage 16 and the upstream side retard passages 14 and 115 is cut off, so that the advance angle passage and the retard angle are reduced. The passage is opened to allow the flow of hydraulic oil, that is, the upstream advance passage 13 and the downstream advance passage 24 communicate with each other, and the upstream retard passage 14 and the downstream retard passage 25 communicate with each other. Then, the hydraulic oil is supplied to the retard chamber 30b through the retard passage (14, 25), and the hydraulic oil is discharged from the advance chamber 30a through the advance passage (13, 24). Further, as shown in FIG. 10, hydraulic oil is supplied through the retard restriction regulating communication path 331 g to apply pressure to the retard restriction lock bar 60, and the retard restriction lock bar 60 unlocks the lock cam 40. Thereby, the phase can be changed by moving the vane rotor 20 to the retard side while preventing the influence of the vanance passage (the supply balance passage 15 and the discharge balance passage 16).

  On the other hand, when the phase is changed to the advance side, the hydraulic oil control valve 113 is switched to the PD port 113a as shown in FIG. Then, the pressure of the hydraulic oil in the second pressure receiving unit 83 is released, and the switching valve 80 receives the pressure of the hydraulic oil guided through the upstream side advance passages 114 and 13 so that the switching valve 80 is a biasing spring. The operation position is maintained against the urging force of 90, the communication between the supply balance passage 15 and the upstream advance passages 13 and 114 is blocked, and the discharge balance passage 16 and the upstream retard passages 14 and 115 are blocked. In the state where communication with the hydraulic fluid is interrupted, the advance angle passage and the retard angle passage are opened so as to allow the flow of hydraulic fluid, that is, the upstream advance angle passage 13 and the downstream advance angle passage 24 communicate with each other. The upstream retard passage 14 and the downstream retard passage 25 communicate with each other, hydraulic fluid is supplied to the advance chamber 30a through the advance passage (13, 24), and the retard chamber through the retard passage (14, 25). The hydraulic oil is discharged from 30b. Further, as shown in FIG. 11, hydraulic oil is supplied through the advance angle restricting side communication passage 331f and pressure is applied to the advance angle restricting lock bar 50, and the advance angle restricting lock bar 50 unlocks the lock cam 40. Thereby, the phase can be changed by moving the vane rotor 20 to the advance side while preventing the influence of the vanance passage (the supply balance passage 15 and the discharge balance passage 16).

  When the vane rotor 20 is held at a predetermined phase angle, the hydraulic oil control valve 113 is switched to the PP port 113c as shown in FIG. Then, the first pressure receiving portion 81 receives the pressure of the hydraulic fluid guided through the upstream side advance passages 114 and 13, and the second pressure receiving portion 83 reduces the pressure of the hydraulic fluid guided through the upstream side retardation passages 115 and 14. By receiving, the switching valve 80 is maintained in the operating position against the urging force of the urging spring 90, the communication between the supply balance passage 15 and the upstream advance passages 13 and 114 is blocked, and the discharge balance In a state where the communication between the passage 16 and the upstream retard passages 14 and 115 is blocked, the advance passage and the retard passage are opened so as to allow the flow of hydraulic oil, that is, with the upstream advance passage 13 and The downstream advance passage 24 communicates, the upstream retard passage 14 communicates with the downstream retard passage 25, and hydraulic oil is supplied to the advance chamber 30a through the advance passages (13, 24). The hydraulic oil passes through the corner passages (14, 25). It is supplied to. At this time, hydraulic oil is supplied through the advance angle restricting communication path 331f and pressure is applied to the advance angle restricting lock bar 50. The advance angle restricting lock bar 50 releases the lock of the lock cam 40, and the retard angle. The hydraulic oil is supplied through the restriction side communication path 331g to apply pressure to the retard restriction lock bar 60, and the retard restriction lock bar 60 releases the lock of the lock cam 40. Thereby, the vane rotor 20 can be maintained at a predetermined phase angle while preventing the influence of the vanance passages (the supply balance passage 15 and the discharge balance passage 16).

  As described above, according to the above valve timing changing device, the engine can be smoothly operated (even at a low temperature) without the occurrence of a hitting sound and without the load caused by the spring force as in the prior art. The engine can be started (complete explosion), and even after the engine is started (complete explosion), an extra load is prevented from being applied, and the phase shift control can be performed smoothly.

In the above embodiment, the housing rotor 30 including the sprocket 32a for transmitting the rotational force of the crankshaft has been shown. However, the present invention is not limited to this, and means for transmitting the rotational driving force of the crankshaft has other structures. (For example, a toothed timing belt), a housing rotor having a structure (toothed pulley, etc.) suitable for the structure can be employed.
In the above-described embodiment, the supply balance passage 15 and discharge lance passage 16 formed in the camshaft 10 and the changeover valve 80 disposed inside the center bolt 70 are shown as the balance passage and the changeover valve constituting the positioning mechanism. However, the present invention is not limited to this, and a configuration in which the vanance passage is formed in the vane rotor may be employed, and a configuration in which the switching valve is disposed at another position may be employed.
In the above-described embodiment, the lock cam 40, the advance angle restricting lock bar 50, the advance angle restricting urging spring 51, the retard angle restricting lock bar 60, and the retard angle restricting urging spring 61 are employed as the lock mechanism. However, the present invention is not limited to this, and a lock cam integrally formed with the vane rotor may be adopted, and the advance angle restricting biasing spring 51 and the retard angle restricting energizing spring 61 are abolished to advance the angle restricting lock. A configuration may be adopted in which the bar and the retard restriction lock bar are urged to the rest position (lock position) by their urging force.

  As described above, the valve timing changing device according to the present invention achieves the simplification of the structure, the reduction in the number of parts, the miniaturization of the entire device, and the like, while preventing an extra load from being applied and controlling the phase of the vane rotor. (Changing the phase to the advance side or retard side) can be performed smoothly, the startability of the engine at low temperatures can be improved, and further, the occurrence of sound and the like at the start of the engine can be prevented. Therefore, it can be applied to an internal combustion engine mounted on an automobile or the like, and is also useful for a small engine mounted on a motorcycle or the like.

DESCRIPTION OF SYMBOLS 10 Camshaft 11 Journal part 12 Cylindrical part 13 Upstream advance passage 14 Upstream retard passage 15 Supply balance passage (positioning mechanism)
16 Discharge balance passage (positioning mechanism)
17 Female thread portion S1 Axis 20 Vane rotor 21 Vane portion 22 Hub portion 23 Through hole 24 Downstream advance passage 25 Downstream retard passage 26 Groove 27, 28 Groove passage 30 Housing rotor 30a Advance chamber 30b Delay chamber 31 Housing member 31a Annular wall 31b Through hole 31c Bearing portion 31d Receiving chamber 31e Recessed portion 31f Advance angle restricting side communicating passage 31g Delay angle restricting side communicating passage 31h, 31i Support shafts S2, S3 Axes 31j, 31k Latching projections 31m, 31n, 31o, 31p Stopper wall 32 Sprocket member 32a Sprocket 32b Inner peripheral surfaces 32c, 32d, 32e Groove passage 33 Cover member 33a Circular hole 40 Lock cam (lock mechanism)
41 Protrusion 42, 43 Cam surface 50 Advance angle regulating lock bar (lock mechanism)
51 Advance angle regulating bias spring (lock mechanism)
60 Retardation restriction lock bar (lock mechanism)
61 Delay angle regulation bias spring (lock mechanism)
70 Center bolt 71 Receiving passage 72 Stopper wall 73 Upstream advance passage 74 Supply balance passage (positioning mechanism)
75 Downstream advance passage 76 Upstream retard passage 77 Discharge balance passage (positioning mechanism)
78 Downstream retarding passage 79 Male thread part 80 Switching valve (positioning mechanism)
81 First pressure receiving portion 82 Communication passage 83 Second pressure receiving portion 84 Communication passage 85 Communication passage 86 Communication passage 87 Spring receiving portion 88 End portion 90 Energizing spring 100 Cap 110 Hydraulic oil control system 111 Pump 112 Drain passage 113 Hydraulic oil control valve (Fluid control valve)
113a PD port 113b DP port 113c PP port 114 Upstream advance passage 115 Upstream retard passage

Claims (9)

A housing rotor that rotates on the axis of the camshaft in conjunction with the rotation of the crankshaft, and a housing chamber that accommodates the housing rotor so as to be relatively rotatable in a predetermined angle range, and the housing chamber is made to advance and retard. A vane rotor that bisects the chamber and rotates integrally with the camshaft; an advance passage that communicates with the advance chamber and allows fluid; a retard passage that communicates with the retard chamber and passes fluid; and the advance A fluid control valve that controls the flow of fluid in the angular passage and the retard passage, and a positioning mechanism that positions the vane rotor at a predetermined intermediate position within the predetermined angular range with respect to the housing rotor when the engine is started, A bubble timing changing device for changing the opening / closing timing of an intake valve or an exhaust valve driven to open / close by a camshaft,
The positioning mechanism includes a balance passage capable of supplying or discharging fluid to and from the advance chamber and the retard chamber to balance the vane rotor at the intermediate position when the engine is started, and the balance passage only when the engine is started. Including a switching valve that switches between opening and closing the balance passage so that fluid flows through
A valve timing changing device characterized by that. The balance passage communicates with the advance chamber when the vane rotor deviates from the intermediate position to the retard side, and communicates with the retard chamber when the vane rotor deviates from the intermediate position to the advance side. A supply vanance passage to be communicated, and when the vane rotor deviates from the intermediate position to the retard angle side, communicates with the retard angle chamber, and when the vane rotor deviates from the intermediate position to the advance angle side, communicates with the advance angle chamber Including a discharge balance passage for discharging fluid,
The valve timing changing device according to claim 1. The switching valve is
The advance passage and the retard passage are respectively bisected into an upstream advance passage, a downstream advance passage, an upstream retard passage, and a downstream retard passage,
A rest position in which the supply balance passage and the discharge balance passage communicate with one and the other of the upstream advance passage and the upstream retard passage, respectively, and the downstream advance passage and the downstream retard passage are blocked; The supply balance passage and the discharge balance passage are cut off, and the advance angle passage and the retard angle passage are opened, and the switch is selectively switched to any one of the operating positions.
The valve timing changing device according to claim 2, wherein: The switching valve is positioned at the rest position by a biasing force of a spring, and receives the fluid pressure generated by the control of the fluid control valve and is switched from the rest position to the operating position while resisting the biasing force of the spring. Formed in the
The valve timing changing device according to claim 3, wherein: The switching valve includes a first pressure receiving portion that receives the pressure of the fluid guided through the upstream side advance passage, and a second pressure receiving portion that receives the pressure of the fluid guided through the upstream side retard passage. The fluid pressure received by at least one of the first pressure receiving portion and the second pressure receiving portion is configured to be switched from the rest position to the operating position while resisting the biasing force of the spring.
The valve timing changing device according to claim 4, wherein: A center bolt for fastening the vane rotor to the camshaft on the axis;
The switching valve is a piston valve that is reciprocally accommodated in an accommodating passage formed in the axial direction with respect to the center bolt,
The center bolt and the switching valve define at least a part of each of the advance passage, the retard passage, the supply balance passage, and the discharge balance passage.
6. The valve timing changing device according to claim 3, wherein the valve timing changing device is a valve timing changing device. Including a lock mechanism that locks the vane rotor at the intermediate position when the engine is started;
The lock mechanism includes a lock cam that rotates integrally with the vane rotor, and a lock bar that is provided on the housing rotor and can be locked by being engaged with the lock cam by an urging force and is unlocked by fluid pressure. ,
The valve timing changing device according to claim 3, wherein the valve timing changing device is a valve timing changing device. A biasing spring that biases the lock bar to engage and lock the lock cam;
The lock bar is associated with the advance angle restricting lock bar that engages with the lock cam to restrict the vane rotor from rotating toward the advance side, and with the lock cam to restrict the vane rotor from rotating toward the retard side. Including a retarded angle regulation lock bar
The urging spring includes an advance angle regulating urging spring that urges the advance angle restricting lock bar to engage and lock the lock cam, and an engaging angle lock spring that engages the lock cam and locks the retard angle restricting lock bar. Including a retard restriction biasing spring that biases
The housing rotor is connected to the advance chamber or the advance passage in a state where the switching valve is in the operating position, and leads the fluid pressure to the advance restriction lock bar so as to release the lock. Including a communication passage and a retardation restriction side communication passage that communicates with the retardation chamber or the retardation passage and guides the pressure of fluid to the retardation restriction lock bar to release the lock.
The valve timing changing device according to claim 7, wherein The lock bar is swingably supported in a vertical plane perpendicular to the axis.
The valve timing changing device according to claim 7 or 8, wherein

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