JP2018100735A - Hydraulic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device capable of improving fuel efficiency.SOLUTION: The hydraulic control device includes a first oil path to which working oil from a hydraulic power source is supplied and which is connected to hydraulic equipment, a second oil path branching from the first oil path for supplying the working oil to a lubricated part of a friction fastening element, and a flow amount change part provided on the second oil path for, when the hydraulic equipment operates, further reducing the flow amount of the working oil to be supplied to the lubricated part than when the hydraulic equipment does not operate.SELECTED DRAWING: Figure 2B

Description

  The present invention relates to a hydraulic control device.

  2. Description of the Related Art Conventionally, there has been known a transmission that includes a clutch provided between an engine and a gear train and transmits a driving force from the engine to the output side via the clutch and the gear train (see, for example, Patent Document 1). ). Patent Document 1 discloses a hydraulic control device that supplies hydraulic oil to hydraulic devices (gear shift actuators, clutch actuators) and lubricated parts (wet multi-plate clutches) in such a transmission. Yes.

JP 2013-245790 A

  However, in the conventional hydraulic control device, the capacity of the mechanical oil pump is set so that the required flow rate of the hydraulic system is ensured during idle operation. Therefore, it is necessary to use a large-capacity mechanical oil pump, and there is a problem that fuel consumption deteriorates.

  The objective of this invention is providing the hydraulic control apparatus which can improve a fuel consumption.

The hydraulic control device according to the present invention includes:
A first oil passage to which hydraulic oil is supplied from a hydraulic source and connected to a hydraulic device;
A second oil passage that branches off from the first oil passage and supplies hydraulic oil to the lubricated portion of the frictional engagement element;
A flow rate changing unit that is provided on the second oil passage and that reduces the flow rate of the hydraulic oil supplied to the lubricated portion when the hydraulic device is operating, compared to when the hydraulic device is not operating;
Is provided.

  According to the present invention, fuel consumption can be improved.

Schematic configuration diagram showing a vehicle to which a lubrication control device according to the present invention is applied. The figure which shows the hydraulic circuit which concerns on this invention, Comprising: The figure which shows the state which is not reducing the amount of lubricating oil The figure which shows the hydraulic circuit which concerns on this invention, Comprising: The figure which shows the state which is reducing the amount of lubricating oil The figure which shows the hydraulic circuit which concerns on a comparative example Flow chart showing the flow of lubricating oil amount switching control

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, embodiment described below is an example and this invention is not limited by this embodiment.

  First, the overall configuration of the vehicle will be described with reference to FIG. As shown in FIG. 1, the vehicle 1 includes an engine 10 and a dual clutch transmission (DCT) 2 including a first clutch 20, a second clutch 30, and a transmission unit 40. The drive wheels are connected to the output side of the DCT 2 through a propeller shaft and a differential gear (not shown) so that power can be transmitted.

  The engine 10 is, for example, a diesel engine. The output speed of the engine 10 (hereinafter referred to as “engine speed NE”) and the output torque are controlled based on the accelerator pedal position Acc of the accelerator pedal detected by the accelerator position sensor 101. An engine speed sensor 102 that detects the engine speed NE is provided on the output shaft 11 of the engine 10.

  The first clutch 20 is a hydraulically operated wet multi-plate clutch having a plurality of input side clutch plates 21 and a plurality of output side clutch plates 22. The input side clutch plate 21 rotates integrally with the engine output shaft 11 of the engine 10. The output side clutch plate 22 rotates integrally with the first input shaft 41 of the transmission unit 40.

  The first clutch 20 is urged in the disconnecting direction by a return spring (not shown), and the piston 23 is moved by the clutch operating hydraulic pressure, so that the input side clutch plate 21 and the output side clutch plate 22 are pressed to contact each other. Is done. When the first clutch 20 is engaged, the power of the engine 10 is transmitted to the first input shaft 41. The connection / disconnection of the first clutch 20 is controlled by the control device 50.

  The second clutch 30 is a hydraulically operated wet multi-plate clutch having a plurality of input side clutch plates 31 and a plurality of output side clutch plates 32. The input side clutch plate 31 rotates integrally with the engine output shaft 11 of the engine 10. The output side clutch plate 32 rotates integrally with the second input shaft 42 of the transmission unit 40.

  The second clutch 30 is urged in the disconnecting direction by a return spring (not shown), and the piston 33 is moved by the clutch operating oil pressure so that the input side clutch plate 31 and the output side clutch plate 32 are pressed against each other. Is done. When the second clutch 30 is engaged, the power of the engine 10 is transmitted to the second input shaft 42. The connection / disconnection of the second clutch 30 is controlled by the control device 50. In the following description, the input side clutch plates 21 and 31 and the output side clutch plates 22 and 32 may be simply referred to as “clutch plates”.

  The second clutch 30 is provided on the outer peripheral side of the first clutch 20. The first input shaft 41 is provided with an unillustrated lubricating oil passage including an axial oil passage and one or a plurality of radial oil passages, and the lubricating oil is injected radially from the first input shaft 41. Thus, each clutch plate of the first clutch 20 is cooled, and further, each clutch plate of the second clutch 30 is cooled. The lubricating oil that has cooled each clutch plate of the second clutch 30 flows out from the outer diameter side of the second clutch 30 and returns to an oil pan (not shown). In this embodiment, the second clutch 30 is provided on the outer peripheral side of the first clutch 20 as an example. However, the arrangement relationship between the first clutch 20 and the second clutch 30 is described here. It is not limited. Specifically, for example, the second clutch 30 may be disposed on the rear side of the first clutch 20.

  The transmission unit 40 includes a first input shaft 41 connected to the output side of the first clutch 20 and a second input shaft 42 connected to the output side of the second clutch 30. The transmission unit 40 includes a sub shaft 43 disposed in parallel with the first input shaft 41 and the second input shaft 42, and an output shaft 44 disposed coaxially with the first input shaft 41 and the second input shaft 42. And. A vehicle speed sensor 103 that detects the speed of the vehicle 1 is provided on the rear end side of the output shaft 44.

  The transmission unit 40 includes a first transmission unit 60, a second transmission unit 70, and a forward / reverse switching unit 80. The first transmission unit 60 includes a first high speed gear train 61, a first low speed gear train 62, and a first coupling mechanism 63.

  The first high-speed gear train 61 is provided so as to mesh with the first input gear 61 a provided so as to be rotatable relative to the first input shaft 41 and the first input gear 61 a and to rotate integrally with the auxiliary shaft 43. And the first auxiliary gear 61b.

  The first low-speed gear train 62 is provided so as to mesh with the second input gear 62 a provided so as to be rotatable relative to the first input shaft 41 and the second input gear 62 a and to rotate integrally with the auxiliary shaft 43. And a second auxiliary gear 62b.

  The first coupling mechanism 63 selectively moves the first input gear 61a and the second input gear 62a to the first input shaft by moving the sleeve 63a in the axial direction (left-right direction in FIG. 1) by the first gear shift actuator 63b. 41 and rotate together.

  The second transmission unit 70 includes a second high speed gear train 71, a second low speed gear train 72, and a second connection mechanism 73. The second high-speed gear train 71 is provided so as to mesh with the third input gear 71 a and the third input gear 71 a provided so as to be rotatable relative to the second input shaft 42 and to rotate integrally with the auxiliary shaft 43. And a third auxiliary gear 71b.

  The second low-speed gear train 72 is provided so as to mesh with the fourth input gear 72 a and the fourth input gear 72 a provided so as to be rotatable relative to the second input shaft 42 and to rotate integrally with the auxiliary shaft 43. And a fourth auxiliary gear 72b.

  The second coupling mechanism 73 selectively rotates the third input gear 71a and the fourth input gear 72a integrally with the second input shaft 42 by moving the sleeve 73a in the axial direction by the second gear shift actuator 73b.

  The forward / reverse switching unit 80 includes a forward gear train 81, a reverse gear train 82, and a third coupling mechanism 83. The forward gear train 81 meshes with the first output gear 81a provided so as to be rotatable relative to the output shaft 44 and the first output gear 81a, and the fifth sub gear provided so as to rotate integrally with the auxiliary shaft 43. And a gear 81b.

  The reverse gear train 82 meshes with the second output gear 82a provided so as to be rotatable relative to the output shaft 44, the second output gear 82a and the idler gear 82c, and is provided so as to rotate integrally with the auxiliary shaft 43. And the sixth sub gear 82b.

  The third coupling mechanism 83 selectively rotates the first output gear 81a and the second output gear 82a integrally with the output shaft 44 by moving the sleeve 83a in the axial direction by the third gear shift actuator 83b.

  Here, a power transmission path in the DCT 2 will be briefly described. For the first speed, the first connecting mechanism 63 connects the second input gear 62a and the first input shaft 41, the third connecting mechanism 83 connects the first output gear 81a and the output shaft 44, and the first clutch. It is established by touching 20. Thereby, the power of the engine 10 is transmitted from the first clutch 20 in the order of the first input shaft 41, the first low speed gear train 62, the countershaft 43, the forward gear train 81, and the output shaft 44.

  For the second speed, the second input mechanism 72 connects the fourth input gear 72a and the second input shaft 42, the third connection mechanism 83 connects the first output gear 81a and the output shaft 44, and the second clutch. It is established by touching 30. Thereby, the power of the engine 10 is transmitted from the second clutch 30 in the order of the second input shaft 42, the second low speed gear train 72, the auxiliary shaft 43, the forward gear train 81, and the output shaft 44.

  In the third speed, the first connection mechanism 63 connects the first input gear 61a and the first input shaft 41, the third connection mechanism 83 connects the first output gear 81a and the output shaft 44, and the first clutch. It is established by touching 20. Thereby, the power of the engine 10 is transmitted from the first clutch 20 in the order of the first input shaft 41, the first high speed gear train 61, the counter shaft 43, the forward gear train 81, and the output shaft 44.

  For the fourth speed, the second connection mechanism 73 connects the fourth input gear 72a and the second input shaft 42, the third connection mechanism 83 connects the first output gear 81a and the output shaft 44, and the second clutch. It is established by touching 30. Thereby, the power of the engine 10 is transmitted from the second clutch 30 in the order of the second input shaft 42, the second low speed gear train 72, the auxiliary shaft 43, the forward gear train 81, and the output shaft 44.

  Further, in the transmission unit 40, for example, after a shift from the first speed to the second speed is performed, a pre-shift is performed in preparation for the next shift from the second speed to the third speed during traveling at the second speed. In this case, specifically, the first gear shift actuator 63b is controlled to release the connection between the second input gear 62a and the first input shaft 41, and the first input gear 61a and the first input shaft 41 are further connected. Link.

  In addition, since the preshift in DCT is a well-known technique, detailed description is abbreviate | omitted. The pre-shift is executed, for example, when the shift map having the accelerator opening Acc and the vehicle speed V as parameters crosses the pre-shift line provided before and after the shift line.

  The control device 50 determines the gear position of the DCT 2 based on the accelerator opening Acc and the vehicle speed V, and controls the connection / disconnection of the first clutch 20, the connection / disconnection control of the second clutch 30, and the gear shift via the hydraulic circuit 90. Various controls such as a shift control of the unit 40 are performed.

  Next, details of the hydraulic circuit 90 of the present invention will be described with reference to the hydraulic circuit diagrams of FIGS. 2A and 2B. 2A and 2B, among the hydraulic control units such as the connection / disconnection control unit of the first clutch 20, the connection / disconnection control unit of the second clutch 30, and the transmission control unit of the transmission unit 40, the first gear shift actuator 63b is connected. Only the relevant configuration is described, and the configuration not related to the present invention is omitted.

  As shown in FIG. 2A, the hydraulic oil sucked up from the oil pan 91 through the filter 91a by the oil pump 92 driven by the engine 10 is supplied to the line pressure oil passage L1, and the line pressure control valve 93 Regulated to pressure. The hydraulic oil in the line pressure oil passage L1 is supplied to the oil passage L7 for driving control of the first gear shift actuator 63b.

  The oil passage L7 is provided with a first shift solenoid valve 63c and a second shift solenoid valve 63d that control driving of the first gear shift actuator 63b. The first and second shift solenoid valves 63c and 63d are normally closed type on-off solenoid valves.

  The first gear shift actuator 63b is biased to the center position (FIG. 2A) by a spring (not shown). Therefore, when both the first shift solenoid valve 63c and the second shift solenoid valve 63d are off, the sleeve 63a does not engage with either the first input gear 61a or the second input gear 62a.

  When the first shift solenoid valve 63c is turned on and the second shift solenoid valve 63d is turned off, the first gear shift actuator 63b is driven rightward (FIG. 2B). Thereby, the sleeve 63a engages with the second input gear 62a, and the second input gear 62a and the first input shaft 41 are connected.

  When the first shift solenoid valve 63c is turned off and the second shift solenoid valve 63d is turned on, the first gear shift actuator 63b is driven leftward. Thereby, the sleeve 63a engages with the first input gear 61a, and the first input gear 61a and the first input shaft 41 are connected.

  The hydraulic oil in the line pressure oil passage L1 is supplied to the oil passage L2. The oil passage L2 is connected to the lubrication flow rate switching valve 95. The line pressure oil passage L1 and the oil passage L2 correspond to the “first oil passage” of the present invention. The lubrication flow rate switching valve 95 corresponds to a “flow rate changing unit” and a “switching valve” of the present invention. The lubrication flow rate switching valve 95 is a pilot hydraulically operated spool valve. The lubrication flow rate switching valve 95 has an input port 95a, a first output port 95b, a second output port 95c, and a pilot port 95d.

  Further, the hydraulic oil in the line pressure oil passage L1 is supplied to the oil passage L3. The oil passage L3 is provided with a solenoid valve 96 that controls the supply of hydraulic oil to the pilot port 95d of the lubrication flow rate switching valve 95. The solenoid valve 96 is a normally closed type on-off solenoid valve.

  The opening and closing of the solenoid valve 96 is controlled by the control device 50. When the solenoid valve 96 is off (the state shown in FIG. 2A), hydraulic fluid is not supplied to the pilot port 95d of the lubrication flow rate switching valve 95. In this case, the spool of the lubricating flow rate switching valve 95 is urged rightward by the spring 95e. Thereby, the input port 95a and the first output port 95b communicate with each other, and the second output port 95c is blocked.

  When the solenoid valve 96 is turned on and hydraulic oil is supplied to the pilot port 95d of the lubrication flow rate switching valve 95 (state of FIG. 2B), the input port 95a and the second output port 95c are communicated with each other. The one output port 95b is blocked.

  An oil passage L4 is connected to the first output port 95b of the lubrication flow rate switching valve 95. A first orifice 97 and an ATF cooler 98 are sequentially provided in the oil passage L4. The oil passage L4 corresponds to the “second oil passage” of the present invention.

  An oil path L5 is connected to the second output port 95c of the lubrication flow rate switching valve 95. A second orifice 99 is provided in the oil passage L5. The length of the second orifice 99 is the same as that of the first orifice 97. The diameter of the second orifice 99 is smaller than the diameter of the first orifice 97. The oil passage L5 corresponds to the “third oil passage” of the present invention.

  The oil passage L4 and the oil passage L5 merge at the downstream side of the ATF cooler 98 and the downstream side of the second orifice 99 to form an oil passage L6. The oil passage L6 is connected to the lubricating oil passage provided on the first input shaft 41 described above. The lubricating oil supplied to the lubricating oil passage is supplied to each clutch plate of the first clutch 20 and the second clutch 30 (hereinafter referred to as “clutch lubricated portion 100”), and then returns to the oil pan 91.

  In the present invention, the pressure loss of the oil passage L5 provided with the second orifice 99 is larger than the pressure loss of the oil passage L4 provided with the first orifice 97 and the ATF cooler 98. Therefore, assuming that the flow rate of the lubricating oil supplied to the oil passage L2 is constant, the flow rate supplied from the oil passage L2 to the oil passage L6 via the oil passage L4 is greater than the oil passage L2 to the oil passage L5. More than the flow rate supplied to the oil passage L6.

  In the present invention, the flow rate of the lubricating oil supplied to the clutch lubricated portion 100 is changed by turning on and off the solenoid valve 96. Specifically, when the solenoid valve 96 is OFF, the lubricating flow rate switching valve 95 is in the left position shown in FIG. 2A, and the lubricating oil supplied to the oil passage L2 is clutched via the oil passage L4 and the oil passage L6. Supplied to the lubricated part 100.

  On the other hand, when the solenoid valve 96 is on, the lubrication flow rate switching valve 95 is in the right position shown in FIG. 2B, and the lubricating oil supplied to the oil passage L2 passes through the oil passage L5 and the oil passage L6, and the clutch lubricated portion. 100.

  As described above, the pressure loss of the oil passage L5 is larger than the pressure loss of the oil passage L4. Therefore, assuming that the flow rate of the lubricating oil supplied to the oil passage L2 is constant, the flow rate of the lubricating oil supplied to the clutch lubricated portion 100 via the oil passage L5 passes through the oil passage L4. In this case, the flow rate of the lubricating oil supplied to the clutch lubricated portion 100 is relatively reduced.

  Here, as a comparative example, a hydraulic circuit 190 having no lubricating flow rate switching function will be described with reference to FIG. 2C. As shown in FIG. 2C, the hydraulic oil sucked up from the oil pan 191 by the oil pump 192 is supplied to the line pressure oil path L11 and further supplied to the oil path L17 for drive control of the gear shift actuator.

  Further, the hydraulic oil in the line pressure oil passage L11 is supplied to the oil passage L12. The oil passage L12 is connected to the lubricating oil passage. The lubricating oil supplied to the lubricating oil passage is supplied to the clutch lubricated portion 200 and then returns to the oil pan 191.

  In the comparative example, the discharge amount required for the oil pump 192 is examined, where Q1 is the flow rate of the hydraulic oil required by the shift control unit during gear shift, and Q2 is the flow rate of the hydraulic oil supplied to the clutch lubricated unit 200.

  Except at the time of gear shift, since the shift control unit does not require hydraulic oil, the discharge amount required for the oil pump 192 is Q2. On the other hand, at the time of gear shifting, the shift control unit requires the hydraulic oil of Q1, so the discharge amount required for the oil pump 192 is Q1 + Q2.

  Therefore, the oil pump 192 is required to have a discharge amount of Q1 + Q2 in order to ensure the flow rate of the hydraulic oil necessary for the entire hydraulic control circuit during the gear shift. Therefore, a large capacity oil pump is required.

  Next, the discharge amount required for the oil pump 92 of this embodiment will be examined. The flow rate of the hydraulic oil required by the speed change control unit at the time of gear shift is assumed to be Q1 as in the comparative example. Further, the flow rate of the hydraulic oil supplied to the clutch lubricated portion 100 when passing through the oil passage L4 is set to Q2 similarly to the flow rate of the hydraulic oil supplied to the clutch lubricated portion 200 in the comparative example. Furthermore, let Q3 (<Q2) be the flow rate of the hydraulic oil supplied to the clutch lubricated portion 100 when passing through the oil passage L5.

  Since the hydraulic oil is not required in the shift control unit except during the gear shift, the discharge amount required for the oil pump 92 is Q2 as in the comparative example. In this embodiment, since the flow rate of the hydraulic oil supplied to the clutch lubricated portion 100 is decreased during gear shift, the flow rate of the hydraulic oil supplied to the clutch lubricated portion 100 during gear shift is Q3 ( <Q2). Therefore, the discharge amount required for the oil pump 92 during gear shift is Q1 + Q3 (<Q1 + Q2).

  Therefore, an oil pump 92 having a discharge amount of Q1 + Q3 is sufficient to ensure the flow rate of the hydraulic oil required for the entire hydraulic control circuit during the gear shift. Therefore, compared with the comparative example in which the flow rate of the hydraulic oil supplied to the clutch lubricated part is constant, the flow rate of the hydraulic oil required by the entire hydraulic control circuit at the time of gear shift is achieved even if a small-capacity mechanical oil pump is used. Can be secured.

  Next, the lubricating oil amount switching control executed in the present invention will be described in detail with reference to the flowchart of FIG. Note that the process of FIG. 3 is repeatedly executed at a predetermined cycle (for example, 10 ms) during engine operation.

  First, in step S1, the control device 50 determines whether or not the hydraulic equipment (here, the first gear shift actuator 63b, the second gear shift actuator 73b, and the third gear shift actuator 83b) is activated.

  For this determination, for example, an operating state of a shift solenoid valve that controls driving of each gear shift actuator is used. Specifically, when the shift solenoid valve is turned on, it can be determined that the hydraulic device has been activated.

  Note that the determination of whether or not the hydraulic device has been activated is not limited to this. Specifically, for example, in the present embodiment, as described above, when the preshift is performed, the hydraulic device operates. Therefore, when the accelerator opening Acc and the vehicle speed V change and straddle the preshift line, it may be determined that the hydraulic device is activated.

  If it is determined in step S1 that the hydraulic device has been operated (step S1: YES), the process proceeds to step S2. In step S2, the control device 50 turns on the solenoid valve 96. Thereby, the lubrication flow rate switching valve 95 is in the right position shown in FIG. 2B. Therefore, the lubricating oil supplied to the oil passage L2 is supplied to the clutch lubricated portion 100 via the oil passage L5 and the oil passage L6.

  If it is not determined in step S1 that the hydraulic device has been activated (step S1: NO), the process proceeds to step S3. In step S3, the control device 50 turns off the solenoid valve 96. Thereby, the lubrication flow rate switching valve 95 is in the left position shown in FIG. 2A. Therefore, the lubricating oil supplied to the oil passage L2 is supplied to the clutch lubricated portion 100 via the oil passage L4 and the oil passage L6.

  As described above, according to the present embodiment, when the hydraulic device is operated, the flow rate of the lubricating oil used for cooling the clutch plate is reduced. For this reason, it is possible to satisfy the flow rate of the hydraulic oil required by the hydraulic device when the hydraulic device is operated without increasing the capacity of the mechanical oil pump. Thereby, fuel consumption can be improved.

  Further, according to the present embodiment, the lubricating flow rate switching valve that selectively connects the oil passage from the oil pump 92 to the clutch lubricated portion 100 to either an oil passage with a relatively large pressure loss or a small oil passage. 95 is provided, and the lubricating flow rate switching valve 95 is switched according to the clutch temperature. Therefore, the lubricating oil flow rate can be changed simply by switching the lubricating flow rate switching valve 95, and the structure can be simplified.

  Further, according to the present embodiment, the lubricating flow rate switching valve 95 is a hydraulic control valve that can be switched by the pilot pressure from the solenoid valve 96. Therefore, the flow rate of the lubricating oil can be changed without using an expensive linear solenoid valve.

  In the above-described embodiment, the flow rate of the lubricating oil supplied to the clutch-lubricated portion 100 is switched in two stages, but the present invention is not limited to this. Specifically, for example, the flow rate of the lubricating oil supplied to the clutch-lubricated portion 100 may be switched between three or more stages, or may be controlled linearly.

  In the above-described embodiment, when the first orifice 97 is passed, the ATF cooler is passed. However, the present invention is not limited to this. Specifically, for example, a switching valve that can select whether or not to pass the ATF cooler may be added to the oil passage L4 so that the passage or not can be selected.

  In the above-described embodiment, the description has been given by taking DCT as an example of the transmission, but the transmission is not limited thereto. The present invention can also be applied to, for example, an automatic mechanical transmission (AMT). In this case, since the hydraulic device is operated at the time of shifting, the determination of the operation of the hydraulic device can be determined when the target gear stage is changed or when the shifting is started.

  The hydraulic control device of the present invention is useful when the flow rate of hydraulic oil used for hydraulic equipment and lubrication is limited.

20 First clutch 30 Second clutch 63b First gear shift actuator 63c First shift solenoid valve 63d Second shift solenoid valve 90, 190 Hydraulic circuit 91, 191 Oil pan 91a Filter 92, 192 Oil pump 93 Line pressure control valve 95 Lubrication flow rate Switch valve 95a Input port 95b First output port 95c Second output port 95d Pilot port 95e Spring 96 Solenoid valve 97 First orifice 98 ATF cooler 99 Second orifice L1, L11 Line pressure oil passage L2, L3, L4, L5, L6 , L7, L12, L17 Oil passage

Claims (2)

A first oil passage to which hydraulic oil is supplied from a hydraulic source and connected to a hydraulic device;
A second oil passage that branches off from the first oil passage and supplies hydraulic oil to the lubricated portion of the frictional engagement element;
A flow rate changing unit that is provided on the second oil passage and that reduces the flow rate of the hydraulic oil supplied to the lubricated portion when the hydraulic device is operating, compared to when the hydraulic device is not operating; Provided hydraulic control device. The flow rate changing unit is a switching valve that selectively connects the second oil passage to a third oil passage or a fourth oil passage having a larger pressure loss than the third oil passage,
The switching valve is switched so as to connect the second oil passage and the fourth oil passage when the hydraulic device operates.
The hydraulic control device according to claim 1.

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