Spool valve device and pump driving method

Abstract

A housing (31) has a first out port (341), an in port (340), and a second out port (342) formed in this order along the axial direction of a valve hole (34). The inner peripheral wall of the valve hole (34) between the ports forms partition walls (343, 344). The spool (40) has body parts (41, 42) of which the outer peripheral walls slide along the partition walls (343, 344) at both ends in the axial direction, and a small-diameter part (43) that forms a communication space with the partition walls (343, 344) at an axial-direction intermediate part. The spool (40) operates such that the in-port (340) and the first out-port (341) communicate with each other during forward rotation of the pump, and the in-port (340) and the second out-port (342) communicate with each other during reverse rotation of the pump. When the operation of the spool (40) is stopped and at all times while the spool is operating, the in port (340) communicates with at least one of the first out port (341) and the second out port (342).

Description

Spool valve device and pump drive method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-043141 filed on March 19, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a spool valve device and a pump driving method.

[0003] Conventionally, there are known techniques for switching between an intake oil passage and a discharge oil passage depending on whether the oil pump is rotating in the forward direction or the reverse direction. For example, Patent Documents 1 and 2 disclose an integrated pump device in which a motor, an oil pump, and a hydraulic actuator are integrated. In some embodiments, the oil pump can rotate in the forward direction and the reverse direction, and a selective shut-off valve is used to switch between the intake oil passage and the discharge oil passage depending on whether the oil pump is rotating in the forward direction or the reverse direction, thereby switching the operating direction of the hydraulic actuator.

[0004] International Publication No. 2022 / 130671 Japanese Patent Application Laid-Open No. 2023-093012

[0005] Patent Document 1 states that "the selective shutoff valve (59) may be configured as a hydraulic switching valve in which a spool is switched by operating pressure." Patent Document 2 also states the same thing. However, if the spool becomes stuck due to the intrusion of contaminants or the like, depending on the position where the spool becomes stuck, the outport of the spool valve device may close, making it impossible to suck in oil.

[0006] Furthermore, in a configuration in which a spool valve device is integrally provided with a pump housing, two types of products may be required in which the spring biases the spool in opposite directions. However, manufacturing two types of pump housings with symmetrical valve holes increases the number of management steps, so a design that allows the use of a common pump housing is required. Patent Documents 1 and 2 do not disclose any means for solving this problem.

[0007] An object of the present disclosure is to provide a spool valve device that improves robustness against influences such as the intrusion of contaminants, and a pump driving method for driving a pump connected to the spool valve device.

[0008] Another object of the present disclosure is to provide a spool valve device that can be assembled into two types of products using a common pump housing, in which the spring biasing directions relative to the spool are opposite to each other.

[0009] The spool valve device of the present disclosure is provided on the suction side of a pump, and the spool operates to switch the suction oil passage depending on the rotation direction of the pump. The pump has a rotor housed in a pump chamber that rotates forward and backward due to the driving force of a rotary power source, thereby discharging the drawn oil. The spool valve device includes a spool and a spring. The spool is housed in a valve hole formed in a housing and is actuated by the operating pressure of the pump depending on the rotation direction of the pump. The spring biases the spool in one direction.

[0010] The housing has, in order along the axial direction of the valve bore, a first out-port connected to a first oil passage that is an intake oil passage during forward rotation of the pump, an in-port connected to the oil tank, and a second out-port connected to a second oil passage that is an intake oil passage during reverse rotation of the pump. The inner circumferential wall of the valve bore between the in-port and first out-port, and between the in-port and second out-port, form partition walls.

[0011] The spool has a body portion and a small diameter portion. The body portion has an outer peripheral wall that slides along the partition wall at both axial ends. The small diameter portion forms a communication space between the axially intermediate portion and the partition wall, allowing communication between the in-port and the first out-port or the second out-port. The spool operates so that the in-port and the first out-port are communicated when the pump is rotated forward, and the in-port and the second out-port are communicated when the pump is rotated reverse.

[0012] In the spool valve device of the first aspect of the present disclosure, the in-port is connected to at least one of the first out-port and the second out-port when the spool is stopped and always during operation. This allows the pump to discharge oil even if the spool stops in an intermediate position due to contamination, preventing malfunction. Furthermore, the function of a check valve can be achieved with a simple structure.

[0013] In a spool valve device according to a second aspect of the present disclosure, the spool is provided with a forward rotation pressure surface and a reverse rotation pressure surface on both axial sides. Here, a region where the hydraulic pressure is higher than the average hydraulic pressure in the pump chamber is defined as a positive pressure region, and a region where the hydraulic pressure is lower than the average hydraulic pressure in the pump chamber is defined as a negative pressure region. The forward rotation pressure surface receives operating pressure for moving the spool in one axial direction from a second hydraulic passage, which is a positive pressure region during forward rotation of the pump. The reverse rotation pressure surface receives operating pressure for moving the spool in the other axial direction from a first hydraulic passage, which is a positive pressure region during reverse rotation of the pump.

[0014] This allows hydraulic pressure to be introduced to operate the spool in both directions, and by reversing the direction of rotation of the pump, contaminants that have entered the clearance between the spool body and the partition wall can be expelled.

[0015] The disclosed pump drive method is a method for driving a pump using a drive circuit of a rotary power source for a spool valve device. The pump is connected to a hydraulic actuator that operates using hydraulic pressure supplied from a pump discharge oil passage and switches a parking lock mechanism between a locked state and an unlocked state depending on the rotation direction of the pump.

[0016] When starting a parked vehicle, the drive circuit rotates the pump so that the spool is biased by the spring and maintained in a stopped state, drawing oil from the oil tank through the oil passage of the spool valve device and operating the hydraulic actuator. This makes it possible to operate the hydraulic actuator when starting a vehicle that has been parked for a long time and has completely drained the oil passage.

[0017] In a spool valve device according to a third aspect of the present disclosure, a valve hole for accommodating a spool is formed in the pump housing. The spool has a spring accommodating hole formed in an end face of one of the body portions, the hole having a bottom surface for supporting the free end of the spring. The valve hole has an insertion opening for the spool that is closed by a plug. A spring seat recess capable of supporting the fixed end of the spring is formed in both the bottom wall of the valve hole and the end face of the plug.

[0018] In this configuration, by reversing the insertion direction of the spool into the valve hole in a common pump housing, two types of products can be assembled: one in which the spring is supported on the bottom wall of the valve hole, and one in which the spring is supported on the end face of the plug. By using a common pump housing for both types of products, the number of management steps can be reduced.

[0019] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 1 is a schematic axial cross-sectional view of an integrated pump device including a spool valve device of this embodiment; FIG. 2 is a cross-sectional view of a pump housing taken along line II-II in FIG. 1; FIG. 3 is a cross-sectional view of a hydraulic actuator taken along line III-III in FIG. 1; FIG. 4 is a cross-sectional view of the spool valve device of the first embodiment when the pump rotates forward (spool stroke 0 mm position); FIG. 5 is a cross-sectional view of the spool valve device of the first embodiment when the pump rotates reverse (spool stroke 4 mm position); FIG. 6 is a cross-sectional view of the spool valve device of the first embodiment when the pump rotates reverse (spool stroke 8 mm position); FIG. 7 is a view showing the relationship between the spool stroke and the opening amount of the out-port; FIG. 8 is a cross-sectional view of the spool valve device of the second embodiment; FIG. 9 is a cross-sectional view of the spool valve device of the third embodiment when the pump rotates forward; 1 is a diagram explaining the accumulation and discharge of contaminants in the enlarged view of part XI in FIGS. 9 and 10 , FIG. 12 is a time chart showing the relationship between pump rotation acceleration and spool operating characteristics, FIG. 13 is a diagram of a spool valve device of a fourth embodiment, FIG. 14 is a configuration diagram of an integrated pump device and a parking lock mechanism, FIG. 15 is a diagram showing a state after being left in a locked state for a long period of time, FIG. 16 is a diagram showing an unlocked state, FIG. 17 is a diagram (1) showing the process of transition from an unlocked state to a locked state, FIG. 18 is a diagram (2) showing the process of transition from the unlocked state to a locked state, FIG. 19 is a diagram showing a locked state, FIG. 20 is a single diagram of a spool used in a spool valve device of a fifth embodiment, FIG. 21 is a diagram of forward direction assembly in the spool valve device of the fifth embodiment, and FIG. 22 is a diagram of reverse direction assembly in the spool valve device of the fifth embodiment.

[0020] Several embodiments of a spool valve device according to the present disclosure will be described with reference to the drawings. In the various embodiments, substantially identical components are designated by the same reference numerals, and descriptions thereof will be omitted. Among the first to fifth embodiments, the first to fourth embodiments are intended to improve robustness against the influence of contamination intrusion, etc. Furthermore, the fifth embodiment allows for the assembly of two types of products using a common pump housing, in which the spring biases the spool in opposite directions.

[0021] In each of the spool valve devices of the first to fifth embodiments, the spool operates in accordance with the rotation direction of the pump to switch oil passages in a hydraulic drive system in which a rotary power source, a pump, and a hydraulic actuator work together. In this hydraulic drive system, the motor serving as the rotary power source, the pump, and the hydraulic actuator may be integrated into one unit. As a representative embodiment described below, a spool valve device integrally provided within an integrated pump device is assumed, and this configuration is referred to as the "present embodiment." Note that spool valve devices applicable to hydraulic drive systems other than integrated pump devices are described in the "Other Embodiments" section.

[0022] The integrated pump device of this embodiment is mounted, for example, on an autonomous electric vehicle. When a command to start or park the vehicle is received from the vehicle's host control device, the pump rotates using the driving force of the motor, generating hydraulic pressure that is supplied to the hydraulic actuator, thereby activating the parking lock mechanism. The integrated pump device also adjusts the amount of oil supplied to the MG based on the MG rotation speed, load condition, etc. while the vehicle is running with the parking lock mechanism unlocked.

[0023] First, a schematic configuration of an integrated pump device including a spool valve device of this embodiment will be described with reference to Figures 1 to 3. As shown in Figure 1, the integrated pump device 10 is configured by arranging a motor 20, a pump 30, and a hydraulic actuator 60, which serve as "rotational power sources," in series, into an integrated device. The motor 20 and the pump 30 are arranged coaxially with a common motor rotation axis O. The vane rotation axis Q of the hydraulic actuator 60 is arranged coaxially with or parallel to the motor rotation axis O. In Figure 1, the portion enclosed by a bold line frame corresponds to the spool valve device 400.

[0024] The motor 20 is, for example, a three-phase brushless motor, and outputs driving force for forward and reverse rotation. The motor 20 includes a stator 22, a motor rotor 23, and a shaft 24, all housed in a motor housing 21. A rotating magnetic field is generated when current is passed through the three-phase windings wound around the stator 22. The motor rotor 23 has multiple magnetic poles arranged circumferentially, and rotates in accordance with the rotating magnetic field of the stator 22. The shaft 24, which is fixed to the motor rotor 23, rotates together with the motor rotor 23.

[0025] The pump 30 discharges the sucked oil by rotating a pump gear 32, which is housed in a pump chamber 33 and serves as a "rotating body," in forward and reverse directions due to the driving force of the motor 20. The pump gear 32 is composed of an internal gear 321 and an external gear 322. The end of the shaft 24 on the pump 30 side is connected to the internal gear 321, and the driving force of the motor 20 is transmitted from the shaft 24 to the internal gear 321.

[0026] A circuit board 26 on which a drive circuit 260 for the motor 20 is mounted is installed in a recessed portion on the side of the pump housing 31 facing the motor 20. The drive circuit 260 controls the rotation direction and speed of the motor 20, thereby controlling the rotation direction and speed of the pump 30.

[0027] The hydraulic actuator 60 has a vane rotor 63 housed in a vane housing 61. The vane rotor 63 rotates within the vane housing 61 by hydraulic pressure supplied from the pump 30 via an oil inlet port of the pump plate 50. The operating direction of the vane rotor 63 switches depending on the rotation direction of the pump 30.

[0028] The vane housing 61 is formed with an inlet 67 and an outlet 68. The inlet 67 communicates with the inlet 340 of the valve hole 34. The outlet 68 communicates with a chamber bottom discharge opening 625 formed in the bottom of the first vane chamber 621 (see FIG. 3). The opening area of ​​the chamber bottom discharge opening 625 changes as the vane rotor 63 operates.

[0029] The configuration of the pump 30 will be described with reference to Figure 2. A pump gear 32 housed in a pump chamber 33 is provided on the side of the pump housing 31 facing the hydraulic actuator 60. In this embodiment, the "housing" of the spool valve device 400 is shared with the pump housing 31, and the spool valve device 400 is provided in the pump housing 31. The spool valve device 400 is provided on the suction side of the pump 30, and the spool 40 operates in accordance with the rotation direction of the pump 30 to switch the suction oil passage.

[0030] In the pump 30, rotation of the shaft 24 causes the internal gear 321 to rotate inside the external gear 322, thereby pumping oil from the pump chamber 33. When viewed from the perspective of Figure 2, clockwise rotation (CW rotation) of the pump gear 32 is defined as "forward rotation," and counterclockwise rotation (CCW rotation) is defined as "reverse rotation." Hereinafter, the rotation direction of the pump gear 32 is also referred to as the "rotation direction of the pump 30."

[0031] The pump housing 31 is formed with a first out-port 341, an in-port 340, and a second out-port 342 in this order along the valve hole 34. The in-port 340 is connected to an oil tank upstream of the oil passage via the suction port 67. The first out-port 341 is connected to the upstream side of the first oil passage 331 and communicates with the pump chamber 33 via the first oil passage 331. The second out-port 342 is connected to the upstream side of the second oil passage 332 and communicates with the pump chamber 33 via the second oil passage 332.

[0032] The downstream sides of the first oil passage 331 and the second oil passage 332 are connected to the vane chambers 621-624 (see FIG. 3) of the hydraulic actuator 60 via oil inlets of the pump plate 50. The oil discharged from the pump chamber 33 is supplied to the vane chambers 621-624 via the second oil passage 332 or the first oil passage 331, and hydraulically operates the vane rotor 63. The operation of the vane rotor 63 will be described later with reference to FIG. 3.

[0033] The spool valve device 400 includes a spool 40 and a spring 45. The spool 40 is housed in a valve hole 34 formed in the pump housing 31 and is actuated by operating pressure from the pump 30 in accordance with the rotation direction of the pump 30. The spring 45 biases the spool in one direction. Of both ends of the spring 45, the end supported by a fixed member is called the "fixed end," and the end supported by the operating spool 40 is called the "free end."

[0034] The operation of the vane rotor 63 in the hydraulic actuator 60 will be described with reference to Figure 3. The vane rotor 63 rotates within the vane housing 61 around the rotation axis Q by hydraulic pressure supplied from the pump 30. The vane housing 61 has, for example, four vane chambers 621-624 inside. The vane chambers 621-624 each have a sector shape with an arc-shaped inner wall on the radially outer side. In the figure, the lead lines of the vane chambers 621-624 are drawn out from the radially outer inner wall.

[0035] The vane rotor 63 is provided with, for example, four vanes 641-644 corresponding to the vane chambers 621-624. A seal is provided on the sliding portion of the radial outer wall of each vane 641-644. Each vane 641-644 is rotatable in the circumferential direction in the corresponding vane chamber 621-624. Lead-side hydraulic chambers 651-654 are formed on one side of the circumferential direction of the vanes 641-644 in the vane chambers 621-624. Furthermore, return-side hydraulic chambers 661-664 are formed on the other side of the circumferential direction of the vanes 641-644. Although not shown, the lead-side hydraulic chambers 651-654 are connected to each other via distribution oil passages. Similarly, the return-side hydraulic chambers 661-664 are connected to each other via distribution oil passages.

[0036] A chamber bottom discharge opening 625 communicating with the discharge port 68 is formed at the bottom of one of the four vane chambers 621. The vane chamber 621 in which the chamber bottom discharge opening 625 is formed is referred to as the "first vane chamber," and the vane 641 housed in the first vane chamber 621 is referred to as the "first vane." In Figure 3, in clockwise order from the first vane chamber 621, the vanes are referred to as the second vane chamber 622, the third vane chamber 623, and the fourth vane chamber 624. Similarly, in clockwise order from the first vane 641, the vanes are referred to as the second vane 642, the third vane 643, and the fourth vane 644.

[0037] The hydraulic actuator 60 operates to switch between an advance state and a return state by hydraulic pressure supplied from the pump 30. When hydraulic pressure is supplied to the advance hydraulic chambers 651-654 by the reverse rotation (CCW rotation) of the pump 30, the vane rotor 63 rotates in one direction (counterclockwise in FIG. 3) to enter the advance state. When hydraulic pressure is supplied to the return hydraulic chambers 661-664 by the forward rotation (CW rotation) of the pump 30, the vane rotor 63 rotates in the other direction (clockwise in FIG. 3) to enter the return state. The upper diagram in FIG. 3 corresponds to the advance state, and the lower diagram corresponds to the return state. The rotational operating angle is represented as θr.

[0038] Here, the terms "advance state" and "return state" are merely terms used to conveniently distinguish between two opposing polar states, and either state may be defined as the advance state or the return state. In this specification, the advance state of the vane rotor 63 corresponds to the P position, and the return state of the vane rotor 63 corresponds to the not P position. The hydraulic actuator 60 locks the parking lock mechanism 80 in the advance state, and unlocks the parking lock mechanism 80 in the return state.

[0039] As described above, the spool valve device 400 of this embodiment switches the intake oil passage of the pump 30 in the integrated pump device 10. However, it is possible that the spool 40 may become stuck due to the intrusion of contaminants mixed in the oil in the oil passage of the spool valve device 400. Depending on the location of the sticking, the outports 341 and 342 of the spool valve device may close, making it impossible to suck in oil.

[0040] Therefore, the spool valve device of the first to fourth embodiments aims to improve robustness against influences such as the intrusion of contaminants. Furthermore, a pump drive method is proposed for operating a hydraulic actuator when starting a vehicle in a state where all oil has been drained from the oil passages after being left parked for a long period of time. Each embodiment will be described in detail below. In the following description of each embodiment, the reference numeral for the "spool valve device" will be omitted.

[0041] First Embodiment A spool valve device according to a first embodiment will be described with reference to FIGS. 4 to 7. FIGS. 4 to 6 show the relationship between the rotation direction of the pump 30, the hydraulic pressure in each oil passage, and the stroke of the spool 40. Here, the region where the hydraulic pressure is higher than the average hydraulic pressure in the pump chamber 33 is defined as the "positive pressure region," and the region where the hydraulic pressure is lower than the average hydraulic pressure in the pump chamber 33 is defined as the "negative pressure region." The first oil passage 331, the second oil passage 332, and the ports 340, 341, and 342 of the valve hole 34 are illustrated with different hatching patterns to distinguish between the positive pressure region and the negative pressure region. The upstream portion of the negative pressure region oil passage from the pump chamber 33 functions as an intake oil passage, and the downstream portion of the positive pressure region oil passage from the pump chamber 33 functions as a discharge oil passage.

[0042] During forward rotation as shown in Fig. 4, the first oil passage 331 becomes a negative pressure region, and the second oil passage 332 becomes a positive pressure region. Therefore, the upstream portion of the first oil passage 331 to which the first out-port 341 is connected is the intake oil passage during forward rotation, and the downstream portion of the second oil passage 332 is the discharge oil passage during forward rotation. During reverse rotation as shown in Figs. 5 and 6, the first oil passage 331 becomes a positive pressure region, and the second oil passage 332 becomes a negative pressure region. Therefore, the upstream portion of the second oil passage 332 to which the second out-port 342 is connected is the intake oil passage during reverse rotation, and the downstream portion of the first oil passage 331 is the discharge oil passage during reverse rotation.

[0043] The detailed configuration of the valve hole 34 and the spool 40 in the spool valve device will now be described. The outer peripheral walls of the body portions 41, 42 of the spool 40 slide along the inner peripheral wall of the valve hole 34. Therefore, the inner diameter of the inner peripheral wall of the valve hole 34 and the outer diameter of the outer peripheral wall of the body portions 41, 42 are formed with fitting dimensions that provide a very small sliding clearance.

[0044] The inner peripheral wall of the valve hole 34 between the in-port 340 and the first out-port 341 and the inner peripheral wall of the valve hole 34 between the in-port 340 and the second out-port 342 respectively form a first partition wall 343 and a second partition wall 344 that separate the oil passages. Hereinafter, the bottom wall side of the valve hole 34 will be referred to as the "front" and the plug 35 side will be referred to as the "rear." A spring chamber 345, which is the space behind the spool 40 in the valve hole 34, houses a portion of the spring 45, including its fixed end. The fixed end of the spring 45 is supported by the end face of the plug 35.

[0045] The spool 40 has body portions 41, 42 whose outer diameters are maximum at both axial ends, and a small-diameter portion 43 in the axial middle whose outer diameter is smaller than that of the body portions 41, 42. The outer peripheral walls of the body portions 41, 42 slide along the partition walls 343, 344. The small-diameter portion 43 forms a communication space 433 between the partition walls 343, 344, which allows communication between the in-port 340 and the first out-port 341 or the second out-port 342.

[0046] The end face of the first body portion 41 located at the front faces the bottom wall of the valve hole 34. The second body portion 42 located at the rear is formed with a spring accommodating hole 425 that accommodates a portion of the spring 45, including its free end. The spring accommodating hole 425 opens into the end face of the second body portion 42 that faces the spring chamber 345. The free end of the spring 45 is supported on the bottom face of the spring accommodating hole 425.

[0047] Regarding the stroke of the spool 40, as shown in FIG. 4 , the position where the end face of the first body portion 41 abuts against the bottom wall of the valve hole 34 due to the biasing force Fsp of the spring 45 is defined as the stroke position of 0 mm. Note that, unlike the third embodiment described below, in the first embodiment, there is no portion that functions as a pressure-receiving surface during forward rotation. At this time, a communication space 433 is formed between the small diameter portion 43 and the first partition wall 343, and the in-port 340 and the first out-port 341 communicate with each other. Oil from the oil tank 91 is drawn from the in-port 340 through the first out-port 341 into the first oil passage 331.

[0048] The hydraulic pressure generated by the pump 30 is supplied from the second oil passage 332 to the return hydraulic chambers 661-664 of the hydraulic actuator 60, and the vane rotor 63 switches from the P position to the not P position (from top to bottom in FIG. 3). The oil in the advance hydraulic chambers 651-654 is returned to the first oil passage 331.

[0049] When the rotation direction of the pump 30 switches from forward to reverse and the first oil passage 331 enters a positive pressure region, the end face of the first body 41 receives the operating pressure as a reverse rotation pressure-receiving surface, as in the third embodiment described below. Therefore, the spool 40 moves rearward toward the plug 35 against the biasing force of the spring 45, increasing the stroke. Figure 5 shows a stroke position of 4 mm during operation of the spool 40. At this time, the flow path from the in-port 340 to the second out-port 342 (see section S) opens before the first body 41 closes the first out-port 341. In other words, the communication space 433 begins to form, replacing the previously closed space between the small diameter portion 43 and the second partition wall 344.

[0050] As the spool 40 moves further rearward, it reaches a position of 8 mm (full stroke) where the end face of the second body portion 42 abuts against the end face of the plug 35, as shown in Figure 6. At this time, as in Figure 5, a communication space 433 is formed between the small diameter portion 43 and the second partition wall 344, and the in-port 340 and the second out-port 342 communicate with each other. Oil in the oil tank 91 is drawn from the in-port 340 through the second out-port 342 into the second oil passage 332.

[0051] The hydraulic pressure generated by the pump 30 is supplied from the first oil passage 331 to the advance hydraulic chambers 651-654 of the hydraulic actuator 60, and the vane rotor 63 switches from the not P position to the P position (from bottom to top in FIG. 3). The oil in the return hydraulic chambers 661-664 is returned to the second oil passage 332.

[0052] When the rotation direction of the pump 30 switches from reverse to forward, the stroke decreases from the state shown in Figure 6, and the flow path from the in-port 340 to the first out-port 341 opens before the second out-port 342 is closed during operation. In this way, the spool 40 operates so that the in-port 340 and the first out-port 341 communicate with each other when the pump 30 rotates forward, and the in-port 340 and the second out-port 342 communicate with each other when the pump 30 rotates reverse.

[0053] As shown in Figure 7, as the stroke of the spool 40 increases, the opening amount of the first out-port 341 decreases and becomes zero when the stroke is 4 mm or more. The opening amount of the second out-port 342 is zero when the stroke is 3 mm or less and increases when the stroke is between 3 mm and 8 mm. Within a 1 mm range of the stroke from 3 to 4 mm, the two out-ports 341, 342 are open together. Even if the spool 40 stops at any intermediate position, one of the out-ports 341, 342 will be open.

[0054] As described above, in the spool valve device of the first embodiment, the in-port 340 communicates with at least one of the first out-port 341 and the second out-port 342 when the spool 40 is stopped and always during operation. This allows the pump 30 to discharge oil even if the spool 40 stops in an intermediate position due to contamination, thereby preventing malfunction. Furthermore, the function of a check valve can be achieved with a simple structure.

[0055] Second Embodiment With reference to Figure 8, a spool valve device according to a second embodiment will be described, focusing on differences in configuration from the first embodiment. The second embodiment differs from the first embodiment in that an external communication oil passage 355 is formed to communicate between the spring chamber 345 and the outside of the pump housing 31. For example, the external communication oil passage 355 is formed to pass through the axial center of the plug 35. This makes it possible to suppress back pressure during spool operation.

[0056] Third Embodiment Next, a spool valve device according to a third embodiment will be described with reference to Figures 9 to 11. Figure 9 shows the operating state of the spool 40 when the pump 30 is rotating in the forward direction, and Figure 10 shows the operating state of the spool 40 immediately after switching from forward to reverse rotation. In the third embodiment, unlike the first embodiment, an out-of-valve communication oil passage 336 is formed in the pump housing 31, connecting the spring chamber 345 with the intake oil passage of the pump chamber 33. In this configuration example, the out-of-valve communication oil passage 336 is formed to connect the spring chamber 345 with the second oil passage 332. Note that when a spring 45 is provided on the first oil passage 331 side, the out-of-valve communication oil passage 336 is formed to connect the spring chamber 345 with the first oil passage 331.

[0057] In the third embodiment, oil can flow in and out between the second oil passage 332 of the pump 30 and the spring chamber 345 via the extra-valve communication oil passage 336, thereby suppressing back pressure during spool operation. Furthermore, when the spool 40 is returned to the set state by the biasing force Fsp of the spring 45, the thrust of the spool 40 is increased with the assistance of hydraulic pressure.

[0058] 9, the end face of the second body portion 42 of the spool 40 and the bottom surface of the spring accommodating hole 425 function as a "forward rotation pressure receiving surface 442" that receives operating pressure that moves the spool 40 in one axial direction (forward) from the second oil passage 332, which becomes a positive pressure area during forward pump rotation. The spool 40 is urged forward by the sum of the urging force Fsp of the spring 45 and the force of the operating pressure received by the forward rotation pressure receiving surface 442.

[0059] 10 , the end face of the first body portion 41 of the spool 40 functions as a "reverse rotation pressure-receiving surface 441" that receives operating pressure for moving the spool 40 in the other axial direction (rearward) from the first oil passage 331, which becomes a positive pressure region when the pump is rotated in reverse. As described above, the spool 40 of the third embodiment has a forward rotation pressure-receiving surface 442 and a reverse rotation pressure-receiving surface 441 provided on both axial sides. Therefore, hydraulic pressure can be introduced to move the spool 40 in both directions.

[0060] 9 and 10 , the mechanism of accumulation and discharge of contaminants at section XI will be described with reference to Figure 11. At section XI, the in-port 340 and the second out-port 342 are adjacent to each other via a second partition wall 344. As the oil flows, contaminants may enter the clearance between the body section 42 and the second partition wall 344.

[0061] As shown in the upper part of Figure 11, during forward pump rotation, the second out-port 342 becomes a positive pressure region and the in-port 340 becomes a negative pressure region. Therefore, in the clearance between the body 42 and the second partition wall 344, oil flows from the second out-port 342 toward the in-port 340. The spool 40 either operates in the same direction as the oil flow, i.e., in the biasing direction of the spring 45 (to the left in the figure), or is biased by the spring 45 from the beginning and remains stationary. Contaminants CT mixed in the oil are drawn into the clearance and accumulate at the inlet edge and inside the clearance.

[0062] As shown in the lower part of Figure 11, when the pump rotates in reverse, the in-port 340 becomes a positive pressure area and the second out-port 342 becomes a negative pressure area. Therefore, oil flows from the in-port 340 toward the second out-port 342 in the clearance between the body 42 and the second partition wall 344. The spool 40 also operates in the same direction as the oil flow, i.e., in the opposite direction to the biasing direction of the spring 45 (to the right in the figure). Contaminants CT accumulated inside the clearance and at the inlet edge are discharged to the second out-port 342 together with the oil.

[0063] In this way, in the third embodiment, the oil passages for the positive pressure region and the negative pressure region are adjacent to each other via a partition wall, and when the rotation direction of the pump is reversed, the positive pressure region and the negative pressure region are switched. Therefore, contaminants that have entered and accumulated in the clearance can be discharged. Furthermore, due to the difference in oil pressure between the adjacent oil passages via the partition wall 344, the direction in which oil flows through the clearance between the body portion 42 and the partition wall 344 coincides with the operating direction of the spool 40. This reduces the sliding resistance of the spool 40.

[0064] Next, with reference to Figure 12, a method for driving the pump 30 by the drive circuit of the motor 20 for the spool valve device of the third embodiment will be described. In the integrated pump device 10 of this embodiment, the drive circuit of the motor 20 corresponds to the "drive circuit of the rotational power source." For example, the drive circuit may be mounted on the board 26 (see Figure 1) inside the integrated pump device 10, or may be provided outside the integrated pump device 10 and send commands to the motor 20 from outside.

[0065] Here, attention is focused on the relationship between the rotational acceleration of the pump 30 (i.e., the increasing gradient of the pump rotation speed) and the operation timing of the spool 40 when the spool 40 is operated by pump reverse rotation (see Figures 10 and 11, bottom row). The upper row of Figure 12 shows a time chart of an example in which the pump rotational acceleration is equal to or greater than a predetermined threshold, while the lower row shows a time chart of a comparative example in which the pump rotational acceleration is less than the predetermined threshold. The example and comparative example compare the pump rotation speed, the oil pressure received by the spool pressure-receiving surface, the oil flow rate, and the spool operation speed.

[0066] In the comparative example, the pump rotation speed and the oil pressure increase gradually, and the spool 40 begins to operate at the same time as the oil flow rate increases. As a result, the spool 40 slides while dragging contaminants along with it, increasing the resistance (i.e., friction).

[0067] In contrast, in the embodiment, the oil pressure rises sharply due to a sudden increase in the pump rotation speed, and the spool 40 begins to operate after the oil flow rate has increased. Because the contaminants are discharged from the clearance before the spool 40 begins to operate, the resistance (friction) exerted by the contaminants when the spool 40 slides is reduced.

[0068] In this way, when operating the spool 40, the drive circuit rotates the pump 30 at a rotational acceleration equal to or greater than a predetermined threshold, and increases the operating pressure received by the spool 40, so that the spool 40 begins to operate only after the flow rate of oil flowing through the clearance between the body 42 and the partition wall 344 has increased. This pump drive method makes it possible to properly discharge contaminants that have entered the clearance and reduce the effect on the sliding of the spool 40.

[0069] Fourth Embodiment A spool valve device according to a fourth embodiment will be described with reference to Figure 13, focusing on differences in configuration from the third embodiment. In the fourth embodiment, an in-valve communication oil passage 426 is formed inside the spool 40, instead of the out-valve communication oil passage 336 of the third embodiment. In this configuration example, the in-valve communication oil passage 426 is formed to communicate between the spring accommodating bore 425 and the second out-port 342. Note that when a spring 45 is provided on the first out-port 341 side, the in-valve communication oil passage 426 is formed to communicate between the spring accommodating bore 425 and the first out-port 341.

[0070] The oil in the spring chamber 345 can flow in and out of the second oil passage 332 via the in-valve communication oil passage 426 and the second out-port 342. Therefore, the fourth embodiment can achieve the same effects as the third embodiment.

[0071] 14 to 19, a method for driving the pump 30 with respect to the spool valve device by the drive circuit of the motor 20 in a system in which the integrated pump device 10 equipped with the spool valve device of any of the first to fourth embodiments is applied to a parking lock mechanism 80 will be described. The drive circuit of the motor 20 corresponds to the "drive circuit of the rotational power source."

[0072] First, operation of the parking lock mechanism 80 by the integrated pump device 10 will be described with reference to Fig. 14. Fig. 14 shows an example of a system configuration. The parking lock mechanism 80 includes a detent mechanism including a detent shaft 81, a detent plate 82, a detent spring 83, and a detent roller 84, as well as a parking rod 85, a cone 86, a parking lock pole 87, a parking gear 88, etc.

[0073] The detent mechanism switches between a P position and a not-P position according to the output of the hydraulic actuator 60. The detent shaft 81 is connected to the rotary shaft of the vane rotor 63 of the hydraulic actuator 60 and rotates in both directions within a predetermined angular range by the operation of the vane rotor 63. The detent plate 82 is fixed to the detent shaft 81 and rotates together with the detent shaft 81. For example, in a two-position detent mechanism, the detent plate 82 has two valleys 821, 822 and a peak 825 on its radially outer edge. In other configurations, a detent mechanism with three or more positions may be used.

[0074] The detent roller 84, supported on the tip of the detent spring 83, fits into one of the two valleys 821, 822 due to the elastic force of the detent spring 83. When a rotational force greater than a predetermined value is applied to the detent plate 82, the detent spring 83 elastically deforms, and the detent roller 84 moves from one valley to the other, overcoming the peak 825. This switches between the P position and the not P position.

[0075] The parking rod 85 is formed in a generally L-shape, and one end 851 is fixed to the detent plate 82. A cone 86 is provided on the other end 852 of the parking rod 85, the diameter of which decreases as it approaches the other end 852. When the detent plate 82 rotates in a direction in which the detent roller 84 fits into the valley portion 821, the cone 86 moves in the direction of arrow P. When the detent plate 82 rotates in a direction in which the detent roller 84 fits into the valley portion 822, the cone 86 moves in the direction of arrow notP.

[0076] A parking lock pole 87 (hereinafter referred to as "pole 87") abuts against the conical surface of the cone 86 and is swingable around a shaft 877. The pole 87 is provided with a protrusion 878 that can mesh with a parking gear 88 (hereinafter referred to as "gear 88"). When the cone 86 moves in the direction of arrow P, the pole 87 is pushed up, and the protrusion 878 meshes with the gear 88, resulting in a locked state. When the cone 86 moves in the direction of arrow not P, the protrusion 878 separates from the gear 88, and the locked state is released.

[0077] As described above, in the integrated pump unit 10, the hydraulic actuator 60 is operated by hydraulic pressure supplied from the pump 30, and switches the parking lock mechanism 80 between a locked state and an unlocked state depending on the rotational direction of the pump 30. The pump 30 is connected to the hydraulic actuator 60. The integrated pump unit 10 realizes a PLA function by operating the hydraulic actuator 60 with hydraulic pressure supplied by the pump 30. Furthermore, the integrated pump unit 10 supplies oil for cooling or lubrication to oil consumers such as the MG97 through an EOP function in which the pump 30 rotates and discharges oil drawn in from an intake port 67 from an outlet port 68.

[0078] 15 to 19 sequentially show the operating states of the spool valve device, pump 30, and hydraulic actuator 60 corresponding to each stage of switching between the locked state and the unlocked state of the parking lock mechanism 80. The configuration of the spool valve device is exemplified by the configuration of the third embodiment, in which an out-of-valve communication oil passage 336 is formed to communicate between the spring chamber 345 and the second oil passage 332.

[0079] The reference numerals for the elements of the hydraulic actuator 60 will collectively refer to the vane chambers 621-624, the vanes 641-644, the advance hydraulic chambers 651-654, and the return hydraulic chambers 661-664 as the "vane chamber 62," "vane 64," "advance hydraulic chamber 65," and "return hydraulic chamber 66," respectively. Also, the vane rotor 63 is not shown, and only the position of the vane 64 in the vane chamber 62 and the discharge port 68 are simply shown.

[0080] When hydraulic oil is supplied from the second oil passage 332 to the return-side hydraulic chamber 66 during forward rotation of the pump 30, or when hydraulic oil is supplied from the first oil passage 331 to the advance-side hydraulic chamber 65 during reverse rotation of the pump 30, the vane 64 moves in the opposite direction. In the parking lock mechanism 80, the pawl 87 moves as the vane 64 moves, switching between a locked state in which the pawl 87 meshes with the gear 88 and an unlocked state in which the pawl 87 disengages from the gear 88. That is, the locked state is established when the vane 64 is in the advance state, and the unlocked state is established when the vane 64 is in the return state.

[0081] 15 shows the state in which the remaining oil in the oil passages of the pump 30 and hydraulic actuator 60 has been completely drained after being left in the locked state (i.e., parked state) for a long period of time. The vane 64 is in the advance state. The spool 40 is biased by the spring 45 to the initial position where it is stopped.

[0082] As shown in Figure 16, when the parking lock mechanism 80 is unlocked from a locked state, i.e., when a parked vehicle is started, the drive circuit rotates the pump 30 in the forward direction, causing the second oil passage 332 to enter a positive pressure region. The spool 40 remains stopped in the initial position shown in Figure 15, and oil is drawn from the oil tank 91 into the first oil passage 331. Hydraulic oil is supplied from the second oil passage 332 to the return hydraulic chamber 66, which operates the vane 64, thereby bringing the parking lock mechanism 80 into an unlocked state. Cooling oil is also discharged from the discharge port 68 of the vane chamber 62 to the MG 97.

[0083] 17, when the vehicle is locked from the unlocked state, i.e., when the vehicle is parked, the drive circuit reverses the rotation of the pump 30, causing the first oil passage 331 to enter a positive pressure region. The head end face of the spool 40 (the pressure-receiving face during normal rotation) then receives operating pressure and begins to operate in the direction opposite to the biasing direction of the spring 45 (to the right in the figure). At this time, the pump 30 sucks up any oil remaining in the oil passage from the pump 30 to the hydraulic actuator 60.

[0084] Figure 18 shows the transition process from the unlocked state to the locked state following the state in Figure 17. When the spool 40 moves and the in-port 340 and the second out-port 342 communicate with each other, the negative pressure region extends to the in-port 340. As shown in Figure 19, when the spool 40 moves further, communication between the in-port 340 and the first out-port 341 is blocked, and oil is drawn from the oil tank 91 into the second oil passage 332. Hydraulic oil is supplied from the first oil passage 331 to the forward hydraulic chamber 65, which operates the vane 64, and the parking lock mechanism 80 enters the locked state.

[0085] As described above, when starting a parked vehicle, the drive circuit rotates the pump 30 so that the spool 40 is biased by the spring 45 and maintained in a stopped state, and oil is drawn from the oil tank 91 via the oil passage of the spool valve device to operate the hydraulic actuator 60. This makes it possible to operate the hydraulic actuator 60 when starting a vehicle in a state where all the oil has been drained from the oil passage after being parked for a long period of time.

[0086] Furthermore, when parking the vehicle, the drive circuit rotates the pump 30 so that the spool 40 operates in the direction opposite to the biasing direction of the spring 45, thereby sucking in oil remaining in the oil passage from the pump 30 to the hydraulic actuator 60. This allows the spool 40 to operate with the above system configuration.

[0087] Fifth Embodiment Next, a spool valve device according to a fifth embodiment will be described with reference to Figures 20 to 22. As shown in Figures 1 and 2, in a configuration in which a spool valve device 400 is integrally provided with a pump housing 31, which is the case of a pump 30, two types of products may be required in which the spring 45 biases the spool 40 in opposite directions. However, manufacturing two types of pump housings 31 with valve holes 34 having symmetrical shapes increases the number of management steps, so a design that allows the use of a common pump housing 31 is required.

[0088] Therefore, the spool valve device of the fifth embodiment aims to be configured so that two types of products can be assembled using a common pump housing 31, in which the spring 45 biases the spool 40 in opposite directions.

[0089] In the description of the fifth embodiment, differences from the first embodiment will be described, mainly regarding the shapes of the spool 40 and the valve hole 34. The description of the first embodiment will be used to cite the relationship between the rotation direction of the pump 30 and the positive and negative pressure regions of the oil passages and the operation of the spool 40, and a description thereof will be omitted. For convenience of illustration, in Figures 21 and 22, the arrangement of the plug 35 side and the bottom wall side of the valve hole 34 is depicted reversed from the drawings of the first embodiment, etc.

[0090] 20 shows the spool 40 used in the fifth embodiment. The spool 40 has body portions 41, 42 whose outer diameters D1, D2 are maximum at both axial ends, and a small-diameter portion 43 in the axial middle where the outer diameter D3 is smaller than the outer diameters D1, D2 of the body portions 41, 42. The outer diameter D1 of the first body portion 41 and the outer diameter D2 of the second body portion 42 are equal, and the length X1 of the first body portion 41 and the length X2 of the second body portion 42 are equal. The outer diameters and lengths of the body portions 41, 42 and the small-diameter portion 43 of the spool 40 are axially symmetrical with respect to a reference line Cs passing through the center of the length X3 of the small-diameter portion 43.

[0091] The second body 42, which is one of the body sections, has a spring accommodating hole 425 formed in the end face, the spring accommodating hole 425 having a bottom surface 427 that opens to the end face and supports the free end of the spring 45 (see FIGS. 21 and 22). The second body 42 has an annular end surface 428 around the spring accommodating hole 425. The first body 41, which is the other body section, is formed solid and has an end surface 418 on the entire surface except for the chamfered outer periphery.

[0092] 21 and 22 , the male thread of the plug 35 is fastened to the female thread formed at the mouth of the valve hole 34, and the insertion opening of the spool 40 in the valve hole 34 is closed by the plug 35. In the fifth embodiment, two assembly methods are possible by reversing the insertion direction of the spool 40 into the valve hole 34.

[0093] 21 , the assembly method in which the spool 40 is inserted into the valve hole 34 with the first body 41 facing the bottom of the hole, the spring 45 is installed in the spring receiving hole 425 of the second body 42, and the plug 35 is fastened is called "forward assembly." In the initial position in which the pump 30 is not rotating in forward assembly, the in-port 340 and the first out-port 341 are connected to form an oil passage.

[0094] 22 , an assembly method in which the spring 45 is first installed at the bottom of the valve hole 34, the spool 40 is then inserted into the valve hole 34 with the second body portion 42 facing the bottom of the hole, and the plug 35 is then fastened is called "reverse assembly." In the initial position in which the pump 30 is not rotating during reverse assembly, the in-port 340 and the second out-port 342 are connected to form an oil passage.

[0095] First, a description will be given of the multiple ports formed in the pump housing 31 along the axial direction of the valve hole 34, including matters common to the first embodiment. In the pump housing 31, a first out-port 341, an in-port 340, and a second out-port 342 are formed in this order from the bottom side along the axial direction of the valve hole 34. In addition, a bottom-side relief port 346 is formed closer to the bottom side of the valve hole 341, and a plug-side relief port 347 is formed closer to the plug 35 than the second out-port 342.

[0096] The opening width W1 of the first out-port 341 is equal to the opening width W2 of the second out-port 342. The distance L1 from the opening width center position C0 of the in-port 340 to the opening width center position C1 of the first out-port 341 is equal to the distance L2 from the opening width center position C0 of the in-port 340 to the opening width center position C2 of the second out-port 342. In other words, in the pump housing 31, the opening widths W1, W2 and opening width center positions C1, C2 of the first out-port 341 and the second out-port 342 are axially symmetrical with respect to the opening width center position C0 of the in-port 340.

[0097] Similarly, the opening width W6 of the bottom-side relief port 346 is equal to the opening width W7 of the plug-side relief port 347. The distance L6 from the center position C0 of the opening width of the in-port 340 to the center position C6 of the opening width of the bottom-side relief port 346 is equal to the distance L7 from the center position C0 of the opening width of the in-port 340 to the center position C7 of the opening width of the plug-side relief port 347. In other words, in the pump housing 31, the opening widths W6 and W7 and the opening width center positions C6 and C7 of the bottom-side relief port 346 and the plug-side relief port 347 are axially symmetrical with respect to the center position C0 of the opening width of the in-port 340.

[0098] As shown in Fig. 2 common to this embodiment, the first out-port 341 is connected to the first oil passage 331, which is the intake oil passage during forward rotation of the pump 30. The in-port 340 is connected to the oil tank 91. The second out-port 342 is connected to the second oil passage 332, which is the intake oil passage during reverse rotation of the pump 30. In Figs. 21 and 22, the inner circumferential walls of the valve hole 34 between the in-port 340 and the first out-port 341, and between the in-port 340 and the second out-port 342, form partition walls 343, 344.

[0099] The outer peripheral walls of the body portions 41, 42 of the spool 40 slide along the partition walls 343, 344. The small diameter portion 43 forms a communication space between the partition walls 343, 344 that allows communication between the in-port 340 and the first out-port 341 or the second out-port 342. The spool 40 operates so that the in-port 340 and the first out-port 341 communicate with each other when the pump 30 rotates forward, and the in-port 340 and the second out-port 342 communicate with each other when the pump 30 rotates reversely.

[0100] Here, a spring seat recess 349 that supports the fixed end of the spring 45 when assembled in the reverse direction is formed in the bottom wall of the valve hole 34. A spring seat recess 359 that supports the fixed end of the spring 45 when assembled in the forward direction is formed in the end face of the plug 35. In other words, spring seat recesses 349, 359 that can support the fixed end of the spring 45 are formed in both the bottom wall of the valve hole 34 and the end face of the plug 35. The free end of the spring 45 is supported by the bottom surface 427 of the spring accommodating hole 425 in both assembly in the forward direction and assembly in the reverse direction.

[0101] In the fifth embodiment, by reversing the insertion direction of the spool 40, two types of products can be assembled: one in which the spring 45 is supported on the bottom wall of the valve hole 34, and the other in which the spring 45 is supported on the end face of the plug 35. By using the same pump housing 31 for both types of products, the number of management steps can be reduced.

[0102] As described above, the spool 40 has axially symmetrical outer diameters and lengths of the body portions 41, 42 and the small-diameter portion 43. Furthermore, the pump housing 31 has axially symmetrical opening widths and opening width centers of the first out-port 341 and the second out-port 342, with the opening width center position of the in-port 340 as the reference. Therefore, equivalent hydraulic characteristics can be obtained when the pump is assembled in the forward direction and when it is assembled in the reverse direction.

[0103] Additionally, an annular receiving surface 348 is formed around the spring seat recess 349 in the bottom wall of the valve hole 34, against which the end face 418 of the first body 41 can abut when initially assembled in the forward direction (when the pump is stopped). An annular receiving surface 358 is formed around the spring seat recess 359 in the end face of the plug 35, against which the end face 418 of the first body 41 can abut when initially assembled in the reverse direction (when the pump is stopped).

[0104] The depth G1 of the spring seat recess 349 formed in the bottom wall of the valve hole 34 and the depth G2 of the spring seat recess 359 formed in the end face of the plug 35 are equal to each other. Therefore, the same spring set load (set length) can be set for forward and reverse assembly, and the characteristics of the spool valve device can be made equal regardless of the assembly direction.

[0105] (Other Embodiments) (a) The spool valve device of the present disclosure is not limited to being installed inside an integrated pump device in which a motor, a pump, and a hydraulic actuator are integrated, but may also be applied to a hydraulic drive system in which a separate motor, a pump, and a hydraulic actuator are connected by electrical wiring and hydraulic piping. The rotational power source of the hydraulic drive system is not limited to a motor, and the system may be one in which the pump is rotated by the driving force of the engine crankshaft.

[0106] (b) Neither the integrated pump device nor the separate hydraulic drive system is limited to the hydraulic actuator 60 operating the parking lock mechanism 80 of the electric vehicle. The output target of the hydraulic actuator 60 may be any mechanism that can be switched between an advance state and a return state. Furthermore, the hydraulic actuator is not limited to a rotary actuator, and a cylinder actuator may also be used.

[0107] (c) In the first to fourth embodiments, the "housing" of the spool valve device does not have to be the same as the "pump housing," and may be provided separately from the pump housing. For example, first out-port 341 and second out-port 342 formed in a housing of the spool valve device alone may be connected to a pump chamber formed in the pump housing by external piping.

[0108] (d) In the pump 30, a rotating body other than a gear may be used as the “rotating body” housed in the pump chamber 33.

[0109] As described above, the present disclosure is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the present disclosure.

[0110] The present disclosure has been described based on the embodiments. However, the present disclosure is not limited to the embodiments and structures. The present disclosure also encompasses various modifications and variations within the scope of equivalents. Furthermore, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A spool valve device is provided on the intake side of a pump (30) that discharges oil by rotating a rotor (32) housed in a pump chamber (33) in a forward and reverse direction by the driving force of a rotary power source (20), and the spool operates in accordance with the rotation direction of the pump to switch the intake oil passage, the device comprising: a spool (40) housed in a valve hole (34) formed in a housing (31) and operated by the operating pressure of the pump in accordance with the rotation direction of the pump; and a spring (45) that biases the spool in one direction; the housing is formed, in order along the axial direction of the valve hole, with a first out-port (341) connected to a first oil passage (331) that is the intake oil passage during forward rotation of the pump, an in-port (340) connected to an oil tank (91), and a second out-port (342) connected to a second oil passage (332) that is the intake oil passage during reverse rotation of the pump; an inner peripheral wall of the valve hole between the in-port and the first out-port, and between the in-port and the second out-port, forming partition walls (343, 344); the spool has: a body portion (41, 42) whose outer peripheral wall slides along the partition walls at both axial ends; and a small-diameter portion (43) at an intermediate axial portion that forms a communication space between the in-port and the first out-port or the second out-port and the small-diameter portion (43) between the body portion (41, 42) and the partition wall, allowing communication between the in-port and the first out-port or the second out-port; the spool valve device operates so that the in-port and the first out-port communicate with each other when the pump is rotating in the forward direction, and so that the in-port and the second out-port communicate with each other when the pump is rotating in the reverse direction; and the in-port and at least either the first out-port or the second out-port communicate with each other when the spool is stopped and constantly during operation.

2. A spool valve device as described in claim 1, wherein a spring chamber (345) that houses a portion including the fixed end of the spring in the valve hole is formed, and an external communication oil passage (355) that communicates with the outside of the housing.

3. A spool valve device as described in claim 1, wherein an outer-valve communicating oil passage (336) is formed in the housing, which communicates between a spring chamber (345) that accommodates a portion of the valve hole including the fixed end of the spring and the first oil passage or the second oil passage of the pump, or wherein an inner-valve communicating oil passage (426) is formed inside the spool, which communicates between a spring accommodating hole (425) that opens into the end face of the spool facing the spring chamber and the first out-port or the second out-port.

4. A spool valve device is provided on the intake side of a pump (30) that discharges oil by rotating a rotor (32) housed in a pump chamber (33) in a forward and reverse direction by the driving force of a rotary power source (20), and the spool operates in accordance with the rotation direction of the pump to switch the intake oil passage, the device comprising: a spool (40) housed in a valve hole (34) formed in a housing (31) and operated by the operating pressure of the pump in accordance with the rotation direction of the pump; and a spring (45) that biases the spool in one direction; and the housing is formed, in order along the axial direction of the valve hole, with a first out-port (341) connected to a first oil passage (331) that is the intake oil passage during forward rotation of the pump, an in-port (340) connected to an oil tank (91), and a second out-port (342) connected to a second oil passage (332) that is the intake oil passage during reverse rotation of the pump, an inner peripheral wall of the valve hole between the in-port and the first out-port, and between the in-port and the second out-port, forming partition walls (343, 344); the spool has: a body portion (41, 42) whose outer peripheral wall slides along the partition walls at both axial ends; and a small-diameter portion (43) at an intermediate axial portion, which forms a communication space between the body portion (41, 42) and the partition wall, allowing communication between the in-port and the first out-port or the second out-port; the pump operates so that the in-port and the first out-port communicate with each other during forward rotation of the pump, and so that the in-port and the second out-port communicate with each other during reverse rotation of the pump; and, defining a region where the oil pressure is higher than the average oil pressure of the pump chamber as a positive pressure region and a region where the oil pressure is lower than the average oil pressure of the pump chamber as a negative pressure region, the spool has: a forward rotation pressure-receiving surface (442) that receives an operating pressure for moving the spool in one axial direction from the second oil passage, which becomes the positive pressure region during forward rotation of the pump; A spool valve device in which reverse pressure receiving surfaces (441) are provided on both axial sides to receive operating pressure that operates the spool in the other axial direction from the first oil passage, which becomes the positive pressure area when the pump is reversed.

5. A spool valve device as described in claim 4, wherein the oil passage of the positive pressure region and the oil passage of the negative pressure region are adjacent to each other via the partition wall, and when the rotation direction of the pump is reversed, the positive pressure region and the negative pressure region are switched.

6. A spool valve device as described in claim 5, wherein the direction in which oil flows through the clearance between the body portion and the partition wall due to the difference in oil pressure between adjacent oil passages via the partition wall coincides with the operating direction of the spool.

7. A method for driving the pump by the drive circuit of the rotary power source for the spool valve device described in claim 6, wherein the drive circuit rotates the pump at a rotational acceleration equal to or greater than a predetermined threshold value when operating the spool, so that the spool begins to operate only after the flow rate of oil flowing through the clearance between the body portion and the partition wall has increased, thereby increasing the operating pressure received by the spool.

8. A spool valve device as claimed in any one of claims 1 to 6, wherein the pump is connected to a hydraulic actuator (60) that operates by hydraulic pressure supplied from the pump and switches the parking lock mechanism (80) between a locked state and an unlocked state depending on the rotation direction of the pump.

9. A pump driving method for a spool valve device according to claim 8, in which the drive circuit of the rotary power source drives the pump, when a parked vehicle is started, so that the drive circuit rotates the pump so that the spool is biased by the spring and maintained in a stopped state, and oil is drawn from the oil tank through the oil passage of the spool valve device to operate the hydraulic actuator.

10. A pump drive method as described in claim 9, wherein, when parking the vehicle, the drive circuit rotates the pump so that the spool operates in the opposite direction to the biasing direction of the spring, thereby sucking in oil remaining in the oil passage from the pump to the hydraulic actuator.

11. A spool valve device is provided on the intake side of a pump (30) that discharges oil by rotating a rotor (32) housed in a pump chamber (33) in forward and reverse directions by the driving force of a rotary power source (20), and the spool operates in accordance with the rotation direction of the pump to switch the intake oil passage, the device comprising: a spool (40) housed in a valve hole (34) formed in a pump housing (31) that is the casing of the pump, and operates with the operating pressure of the pump in accordance with the rotation direction of the pump; and a spring (45) that biases the spool in one direction; the pump housing is formed, in order along the axial direction of the valve hole, with a first out-port (341) connected to a first oil passage (331) that is the intake oil passage during forward rotation of the pump, an in-port (340) connected to an oil tank (91), and a second out-port (342) connected to a second oil passage (332) that is the intake oil passage during reverse rotation of the pump; The inner peripheral walls of the valve holes between the in-port and the first out-port, and between the in-port and the second out-port, form partition walls (343, 344), the spool has body portions (41, 42) whose outer peripheral walls slide along the partition walls at both axial ends, and a small-diameter portion (43) at an intermediate axial portion that forms a communication space between the body portion (41, 42) and the partition wall to allow communication between the in-port and the first out-port or the second out-port, the in-port and the first out-port communicate with each other when the pump is rotated forward, and the in-port and the second out-port communicate with each other when the pump is rotated reverse, the body portion on one side of the spool has a spring accommodating hole (425) that opens at an end face and has a bottom surface (427) that supports a free end of the spring, the valve hole has an insertion opening for the spool that is closed with a plug (35), A spool valve device in which a spring seat recess (349, 359) capable of supporting a fixed end of the spring is formed on both the bottom wall of the valve hole and the end face of the plug.

12. A spool valve device as described in claim 11, wherein the spool has axially symmetrical outer diameters and lengths of the body portion and the small diameter portion, and the pump housing has axially symmetrical opening widths and opening width center positions of the first out-port and second out-port with the opening width center position of the in-port as the reference.

13. A spool valve device as set forth in claim 11 or 12, wherein annular receiving surfaces (348, 358) against which the end face of the body portion can abut are formed around the spring seat recess in the bottom wall of the valve hole and the end face of the plug, and the depths of the spring seat recesses formed in the bottom wall of the valve hole and the end face of the plug are equal to each other.

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