Hydraulic control device

Abstract

To reduce a cost of a hydraulic control device by selectively supplying hydraulic pressure from one pressure regulation valve to two hydraulic engagement elements, and to improve efficiency.SOLUTION: A first selector valve of a hydraulic control device permits a flow-out of oil from a second signal pressure output valve when first signal pressure is not supplied and when the first signal pressure and second signal pressure are supplied. A second selector valve permits the supply of hydraulic pressure to a second hydraulic engagement element side from a dual-use pressure regulation valve when the second signal pressure is not supplied, and permits the supply of the hydraulic pressure to a first hydraulic engagement element side from the dual-use pressure regulation valve when the second signal pressure is supplied. A third selector valve permits the supply of the hydraulic pressure or original pressure from the dual-use pressure regulation valve to the second hydraulic engagement element when the second signal pressure is not supplied, and regulates the supply of the hydraulic pressure or the original pressure from the dual-use pressure regulation valve to the second hydraulic engagement element when the second signal pressure is supplied.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a hydraulic control device for a transmission that selectively engages at least any two of a plurality of hydraulic engagement elements to form a plurality of forward speeds and reverse speeds. [Background technology]

[0002] Conventionally, there is known an automatic transmission equipped with five hydraulic engaging elements, including a first hydraulic engaging element (B2) that is engaged when first forward gear and reverse gear are established, a second hydraulic engaging element (C1) that is engaged when first forward gear is established and disengaged when reverse gear is established, and a third hydraulic engaging element (C3) that is disengaged when first forward gear is established and engaged when third forward gear and reverse gear are established (see, for example, Patent Document 1). This automatic transmission establishes first to sixth forward gears and reverse gear by engaging any two of the five hydraulic engaging elements, and establishes first forward gear by engaging the first hydraulic engaging element (B2) and the second hydraulic engaging element (C1). The hydraulic control device, which supplies hydraulic pressure to the five hydraulic engagement elements, includes a first solenoid valve capable of outputting a first signal hydraulic pressure, a second solenoid valve capable of outputting a second signal hydraulic pressure, a first changeover valve, a second changeover valve, and five linear solenoid valves that adjust source pressures (line pressures) to generate engagement pressures for the corresponding hydraulic engagement elements. The first changeover valve selectively outputs the source pressure as a forward range pressure and outputs the source pressure as a non-forward range pressure by supplying or discharging the first signal hydraulic pressure. The second changeover valve selectively outputs a first state, in which a forward range pressure supplied to a first input port is output from a first output port, and a second state, in which a non-forward range pressure supplied to a second input port is output from a first output port by supplying or discharging the second signal hydraulic pressure. Furthermore, the five linear solenoid valves include a first linear solenoid valve that adjusts the source pressure to generate a first engagement pressure for the first hydraulic engagement element, a second linear solenoid valve that adjusts the forward range pressure to generate a second engagement pressure for the second hydraulic engagement element, and a third linear solenoid valve that adjusts the hydraulic pressure output from the first output port of the second switching valve to generate a third engagement pressure for the third hydraulic engagement element.

[0003] In this hydraulic control device, even if a failure occurs in two of the first selector valve, the first linear solenoid valve, and the second linear solenoid valve, causing at least one of the second engaging element and the first engaging element to engage, unintended shifting can be prevented by controlling the remaining valve. The second selector valve selectively switches between a state in which forward range pressure or non-forward range pressure is supplied to the third hydraulic engaging element and a state in which the supply of forward range pressure or non-forward range pressure to the third hydraulic engaging element is blocked. Furthermore, when the gear is shifted from reverse to first forward gear, the second selector valve is maintained in the second state by the second signal hydraulic pressure from the second solenoid valve until the second engaging element changes from a disengaged state to at least an engaged state. This allows the second selector valve to block the supply of forward range pressure to the third linear solenoid valve even if an open failure occurs in the third linear solenoid valve, thereby suppressing shock caused by the third hydraulic engaging element and the first hydraulic engaging element remaining engaged. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-065963 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional hydraulic control device described above, a linear solenoid valve is provided for each of the multiple hydraulic engagement elements of the automatic transmission. However, linear solenoid valves are expensive and have a high rate of oil leakage, so in order to reduce the cost and improve the efficiency of the hydraulic control device, it is preferable to reduce the number of linear solenoid valves in the hydraulic control device.

[0006] Therefore, a main object of the present disclosure is to reduce the cost and improve the efficiency of a hydraulic control device by selectively supplying hydraulic pressure to two hydraulic engagement elements from one pressure regulating valve. [Means for solving the problem]

[0007] The hydraulic control device of the present disclosure is a hydraulic control device (60, 60B) of a transmission (25) that selectively engages at least any two of a first hydraulic engagement element (C2), a second hydraulic engagement element (B2) that is engaged when at least a reverse gear is formed and is not simultaneously engaged with the first hydraulic engagement element (C2), and remaining hydraulic engagement elements (C1, C3, C4, B1) to form a plurality of forward gears and the reverse gear, and the hydraulic control device (60, 60B) of the transmission (25) that selectively engages at least any two of a first hydraulic engagement element (C2), a second hydraulic engagement element (B2) that is engaged when at least a reverse gear is formed and is not simultaneously engaged with the first hydraulic engagement element (C2), and remaining hydraulic engagement elements (C1, C3, C4, B1) a plurality of pressure regulating valves including a pressure regulating valve (SL2), and at least one dedicated pressure regulating valve (SL1, SL3, SL4, SL5) for adjusting the source pressure (PL) to generate hydraulic pressure to the corresponding remaining hydraulic engaging elements (C1, C3, C4, B1); a first signal pressure output valve (SC1) for outputting a first signal pressure (Psc1); a second signal pressure output valve (SC2) for outputting a second signal pressure (Psc2); a first switching valve (100, 100B) that operates by receiving a supply of the first signal pressure (Psc1) and a supply of both the first and second signal pressures (Psc1, Psc2), and that allows at least the oil supplied from the second signal pressure output valve (SC2) to flow out when the first switching valve (100, 100B) is not supplied with the first signal pressure (Psc1) and when the first switching valve (100, 100B) is supplied with both the first and second signal pressures (Psc1, Psc2); and a first switching valve (100, 100B) that operates by receiving a supply of the second signal pressure (Psc2) and a second signal pressure output valve (SC2) that allows at least the oil supplied from the second signal pressure output valve (SC2) to flow out when the second signal pressure (Psc2) is not supplied from the second signal pressure output valve (SC2), and a second switching valve (200) that, when receiving the second signal pressure (Psc2) from the second signal pressure output valve (SC2), allows the supply of the hydraulic pressure (Psl2) from the dual-purpose pressure regulating valve (SL2) to the first hydraulic engagement element (C2) side and regulates the supply of the hydraulic pressure (Psl2) from the dual-purpose pressure regulating valve (SL2) to the second hydraulic engagement element (B2) side;200B), and a third switching valve (300, 300B) that allows the supply of the hydraulic pressure (Psl2) from the dual-purpose pressure regulating valve (SL2) to the second hydraulic engagement element (B2) from the second switching valve (200) when the second signal pressure (Psc2) is not supplied from the second signal pressure output valve (SC2), and that restricts the supply of the hydraulic pressure (Psl2) from the dual-purpose pressure regulating valve (SL2) to the second hydraulic engagement element (B2) from the second switching valve (200, 200B) when the second signal pressure (Psc2) is supplied from the second signal pressure output valve (SC2).

[0008] In the hydraulic control device of the present disclosure, hydraulic pressure generated (adjusted) by the dual-purpose pressure regulating valve can be supplied to a first hydraulic engagement element and a second hydraulic engagement element that is engaged at least when the transmission is in reverse gear but is not simultaneously engaged with the first hydraulic engagement element. This makes it possible to reduce the number of pressure regulating valves in the hydraulic control device, thereby reducing costs by eliminating the pressure regulating valves and improving efficiency by reducing oil leakage. As a result, the hydraulic control device of the present disclosure can selectively supply hydraulic pressure to two hydraulic engagement elements from one pressure regulating valve, thereby reducing costs and improving efficiency. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with a power transmission device including a hydraulic control device of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of a power transmission device mounted on the vehicle of FIG. [Figure 3] 3 is an operation table showing the relationship between each gear position of the transmission included in the power transmission device of FIG. 2 and the operating state of the hydraulic engagement elements. [Figure 4] 1 is a system diagram showing a main part of a hydraulic control device of the present disclosure. [Figure 5] 4 is an operation table showing energization states of solenoid valves included in the hydraulic control device of the present disclosure. [Figure 6] FIG. 2 is a system diagram for explaining the operation of the hydraulic control device of the present disclosure. [Figure 7] FIG. 2 is a system diagram for explaining the operation of the hydraulic control device of the present disclosure. [Figure 8] FIG. 2 is a system diagram for explaining the operation of the hydraulic control device of the present disclosure. [Figure 9] FIG. 2 is a system diagram for explaining the operation of the hydraulic control device of the present disclosure. [Figure 10] FIG. 2 is a system diagram for explaining the operation of the hydraulic control device of the present disclosure. [Figure 11] FIG. 2 is a system diagram for explaining the operation of the hydraulic control device of the present disclosure. [Figure 12] FIG. 4 is a system diagram showing a main part of another hydraulic control device of the present disclosure. [Figure 13] 10 is an operation table showing energization states of solenoid valves included in another hydraulic control device of the present disclosure. [Figure 14] FIG. 4 is a system diagram for explaining the operation of another hydraulic control device of the present disclosure. [Figure 15] FIG. 4 is a system diagram for explaining the operation of another hydraulic control device of the present disclosure. [Figure 16] FIG. 4 is a system diagram for explaining the operation of another hydraulic control device of the present disclosure. [Figure 17] FIG. 4 is a system diagram for explaining the operation of another hydraulic control device of the present disclosure. [Figure 18] FIG. 4 is a system diagram for explaining the operation of another hydraulic control device of the present disclosure. [Figure 19] FIG. 4 is a system diagram for explaining the operation of another hydraulic control device of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0011] Fig. 1 is a schematic configuration diagram of a vehicle 10 equipped with a power transmission device 20 including a hydraulic control device 60 according to the present disclosure. The vehicle 10 shown in the figure is a front-wheel drive vehicle having an engine 12 and a power transmission device 20 that transmits power from the engine 12 to left and right drive wheels (front wheels) DW. As shown in Fig. 1, the vehicle 10 also includes an engine electronic control unit (hereinafter referred to as "EGECU") 14 that controls the engine 12, a brake electronic control unit (hereinafter referred to as "brake ECU") 16 that controls an electronically controlled hydraulic brake unit (not shown), and a transmission electronic control unit (hereinafter referred to as "TMECU") 21 that controls the power transmission device 20.

[0012] The EGECU 14 is a microcomputer including a CPU (not shown) and receives signals from various sensors, such as a crankshaft position sensor (not shown) that detects the rotational position of the crankshaft of the engine 12, an accelerator pedal position sensor 92 that detects the depression amount (operation amount) of an accelerator pedal 91, and a vehicle speed sensor 99, as well as signals from the brake ECU 16 and the TMECU 21. Based on these signals, the EGECU 14 controls electronically controlled throttle valves, fuel injection valves, spark plugs, and other components (not shown). The brake ECU 16 is also a microcomputer including a CPU (not shown) and receives signals from various sensors, such as a master cylinder pressure sensor 94 that detects a master cylinder pressure corresponding to the depression amount of a brake pedal 93, and a vehicle speed sensor 99, as well as signals from the EGECU 14. The brake ECU 16 controls a brake actuator (hydraulic actuator), and other components (not shown), based on these signals.

[0013] The TMECU 21 is also a microcomputer including a CPU (not shown), and receives signals from various sensors, such as a shift position sensor 96 that detects the shift position, which is the operating position of the shift lever 95, the accelerator pedal position sensor 92, a vehicle speed sensor 99, and an input rotation speed sensor that detects the input rotation speed of the automatic transmission 25 (the rotation speed of the turbine runner 23b or the input shaft 26 of the automatic transmission 25), as well as signals from the EGECU 14 and the brake ECU 16. The TMECU 21 controls the power transmission device 20 based on these signals. In this embodiment, the shift positions of the shift lever 95 include a parking position (P) selected when parking, a reverse position (R) for reverse travel, a neutral position (N) for cutting off the transmission of power by the automatic transmission 25, and a drive position (D) for normal forward travel, as well as a sport position (S) that allows the driver to select any gear.

[0014] As shown in FIG. 2, the power transmission device 20 includes a transmission case 22, a starting device (fluid transmission device) 23 housed within the transmission case 22, a mechanical oil pump 24 driven by power from the engine 12, an automatic transmission 25, a gear mechanism (gear train) 40, a differential gear (differential mechanism) 50, a hydraulic control device 60, and the like.

[0015] The transmission case 22 includes a housing 22a, a transaxle case 22b fastened (fixed) to the housing 22a, a front support 22c fastened (fixed) to the transaxle case 22b so as to be positioned between the housing 22a and the transaxle case 22b, and a center support 22d fastened (fixed) to the transaxle case 22b. In this embodiment, the housing 22a, the transaxle case 22b, and the center support 22d are made of, for example, an aluminum alloy, and the front support 22c is made of steel (iron alloy) or an aluminum alloy.

[0016] The starting device 23 includes a front cover connected to the crankshaft of the engine 12 via a drive plate or the like (not shown), an input-side pump impeller 23p having a pump shell tightly fixed to the front cover, an output-side turbine runner 23t connected to an input shaft 26 of an automatic transmission 25, a stator 23s arranged inside the pump impeller 23p and turbine runner 23t to straighten the flow of hydraulic oil from the turbine runner 23t to the pump impeller 23p, and a one-way clutch 23o supported by a stator shaft (not shown) and limiting the rotation direction of the stator 23s to one direction. The pump impeller 23p, turbine runner 23t, and stator 23s form a torque converter that has a torque amplifying effect.

[0017] Furthermore, the starting device 23 includes a lockup clutch 23c that connects and disconnects the front cover and the input shaft 26 of the automatic transmission 25, and a damper device 23d that damps vibrations between the front cover and the input shaft 26 of the automatic transmission 25. In this embodiment, the lockup clutch 23c is configured as a multi-plate friction hydraulic clutch having a plurality of friction engagement plates (friction plates and separator plates). However, the lockup clutch 23c may also be a single-plate friction hydraulic clutch. The starting device 23 may also include a fluid coupling that does not have a stator 23s.

[0018] The mechanical oil pump 24 is a gear pump that includes an external gear (inner rotor) 241 connected to the pump impeller 23p of the starting device 23 via a wrapping transmission mechanism 240, an internal gear (outer rotor) 242 meshing with the external gear 241, a pump body and a pump cover (neither of which are shown) that define a gear chamber (not shown) that houses the external gear 241 and the internal gear 242, and is disposed on an axis separate from the input shaft 26 of the automatic transmission 25. The mechanical oil pump 24 is driven by power from the engine 12 via the wrapping transmission mechanism 240, and draws in hydraulic oil (ATF) stored in a hydraulic oil reservoir (not shown) provided at the bottom of the transaxle case 22b, and pumps it out to the hydraulic control device 60. The wrapping transmission mechanism 240 includes a drive sprocket that rotates integrally with the pump impeller 23p of the starting device 23, a driven sprocket that rotates integrally with the external gear 241 of the mechanical oil pump 24, and a chain that is wrapped around the drive sprocket and driven sprocket.

[0019] The automatic transmission 25 is configured as an eight-speed transmission, and as shown in FIG. 2, includes a double-pinion first planetary gear mechanism 30, a Ravigneaux second planetary gear mechanism 35, four clutches C1, C2, C3, and C4 as hydraulic engagement elements for changing the power transmission path from the input side to the output side, and two brakes B1 and B2.

[0020] The first planetary gear mechanism 30 has a sun gear (fixed element) 31 which is an external gear, a ring gear 32 which is an internal gear arranged concentrically with the sun gear 31, and a planetary carrier 34 which holds a plurality of pairs of two pinion gears 33a, 33b which mesh with each other and in which one meshes with the sun gear 31 and the other with the ring gear 32, so that the pairs can rotate (rotate) and revolve. As shown in the figure, the sun gear 31 of the first planetary gear mechanism 30 is non-rotatably connected (fixed) to the transmission case 22 via the front support 22c, and the planetary carrier 34 of the first planetary gear mechanism 30 is connected to the input shaft 26 so as to be rotatable integrally therewith. The first planetary gear mechanism 30 is also used as a so-called reduction gear, and reduces the speed of power transmitted to the planetary carrier 34, which is the input element, and outputs the reduced power from the ring gear 32, which is the output element.

[0021] The second planetary gear mechanism 35 has a first sun gear 36a and a second sun gear 36b which are external gears, a ring gear 37 which is an internal gear arranged concentrically with the first and second sun gears 36a, 36b, a plurality of short pinion gears 38a which mesh with the first sun gear 36a, a plurality of long pinion gears 38b which mesh with the second sun gear 36b and the plurality of short pinion gears 38a and also mesh with the ring gear 37, and a planetary carrier 39 which holds the plurality of short pinion gears 38a and the plurality of long pinion gears 38b so that they can rotate freely (rotate freely) and revolve freely. The ring gear 37 of the second planetary gear mechanism 35 functions as an output member of the automatic transmission 25, and the power transmitted from the input shaft 26 to the ring gear 37 is transmitted to the left and right drive wheels via the gear mechanism 40, the differential gear 50 and the drive shaft 51.

[0022] The clutch C1 connects and disconnects the ring gear 32 of the first planetary gear mechanism 30 and the first sun gear 36a of the second planetary gear mechanism 35 to and from each other. The clutch C2 connects and disconnects the input shaft 26 and the planetary carrier 39 of the second planetary gear mechanism 35 to and from each other. The clutch C3 connects and disconnects the ring gear 32 of the first planetary gear mechanism 30 and the second sun gear 36b of the second planetary gear mechanism 35 to and from each other. The clutch C4 connects and disconnects the planetary carrier 34 of the first planetary gear mechanism 30 and the second sun gear 36b of the second planetary gear mechanism 35 to and from each other. In this embodiment, clutches C1, C2, C3 and C4 are multi-plate friction hydraulic clutches including a piston, a plurality of friction engagement plates (friction plates and separator plates), an engagement oil chamber to which engagement oil pressure (hydraulic oil) is supplied from the hydraulic control device 60, a centrifugal oil pressure cancellation chamber to which hydraulic oil is supplied from the hydraulic control device 60 to cancel the centrifugal oil pressure generated in the engagement oil chamber, etc.

[0023] Brake B1 fixes (connects) second sun gear 36b of second planetary gear mechanism 35 to transmission case 22 so as not to rotate, and releases the fixation of second sun gear 36b to transmission case 22. Brake B2 fixes planetary carrier 39 of second planetary gear mechanism 35 to transmission case 22 so as not to rotate, and releases the fixation of planetary carrier 39 to transmission case 22. In this embodiment, multi-plate friction hydraulic brakes including a piston, a plurality of friction engagement plates (friction plates and separator plates), an engagement oil chamber to which hydraulic oil is supplied, and the like are used as brakes B1 and B2.

[0024] These clutches C1-C4 and brakes B1 and B2 operate by receiving hydraulic fluid supplied and discharged from the hydraulic control device 60. FIG. 3 shows an operation table illustrating the relationship between each gear of the automatic transmission 25 and the operating states of the clutches C1-C4 and brakes B1 and B2. The automatic transmission 25 provides forward first through eighth gears and reverse first and second gears by setting the clutches C1-C4 and brakes B1 and B2 to the states shown in the operation table of FIG. 3. In other words, each gear of the automatic transmission 25 is formed by engaging any two of the clutches C1-C4 and brakes B1 and B2. Note that at least one of the clutches C1-C4 and brakes B1 and B2 may be a meshing engagement element such as a dog clutch.

[0025] The gear mechanism 40 includes a counter drive gear 41, a counter shaft 42, a counter driven gear 43, a drive pinion gear 44, and a differential ring gear 45. The counter drive gear 41 is connected to the ring gear 37 of the second planetary gear mechanism 35 of the automatic transmission 25, and the counter shaft 42 extends parallel to the input shaft 26 of the automatic transmission 25. The counter driven gear 43 is fixed to the counter shaft 42 and meshes with the counter drive gear 41. The drive pinion gear 44 is formed on (or fixed to) the counter shaft 42, and the differential ring gear 45 meshes with the drive pinion gear 44 and is connected to a differential gear 50.

[0026] FIG. 4 is a system diagram showing the main components of the hydraulic control device 60. The hydraulic control device 60 is connected to the mechanical oil pump 24, which is capable of drawing and discharging hydraulic oil from a hydraulic oil reservoir in the transaxle case 22b through a strainer. The hydraulic control device 60 is controlled by the TMECU 21. The hydraulic control device 60 generates hydraulic pressure required by the starting device 23 and the automatic transmission 25, and supplies hydraulic oil to low-pressure oil supply units (lubricated parts) such as various bearings and centrifugal hydraulic cancel chambers of the clutches C1-C4. As shown in the figure, the hydraulic control device 60 includes a valve body 600 having a plurality of oil passages formed therein, a primary regulator valve, a secondary regulator valve, and a modulator valve (all of which are not shown), linear solenoid valves SL1, SL2, SL3, SL4, and SL5, a first signal pressure output valve SC1, a second signal pressure output valve SC2, a third signal pressure output valve SC3, a first switching valve 100, a second switching valve 200, and a third switching valve 300. In this embodiment, the hydraulic control device 60 does not have a manual valve that operates in conjunction with the shift lever 95, and constitutes a shift-by-wire system together with the TMECU 21. That is, the TMECU 21 controls the hydraulic control device 60 so that the automatic transmission 25 is in a state that corresponds to the shift position of the shift lever 95 set by the driver.

[0027] The valve body 600 is attached to, for example, a side portion of the transaxle case 22b that constitutes the transmission case 22. A primary regulator valve (not shown) of the hydraulic control device 60 adjusts the pressure of hydraulic oil supplied from the mechanical oil pump 24 to an oil passage L1 of the valve body 600, i.e., line pressure PL, in response to a signal pressure supplied from a linear solenoid valve (not shown). The linear solenoid valve that outputs the signal pressure is controlled by the TMECU 21 to adjust the pressure of hydraulic oil from the mechanical oil pump 24 side (e.g., a modulator valve) and output a pressure corresponding to the accelerator opening or throttle valve opening of the vehicle 10. The secondary regulator valve adjusts the pressure of hydraulic oil drained from the primary regulator valve in response to the signal pressure from the linear solenoid valve to generate a secondary pressure (circulation pressure) lower than the line pressure PL. Furthermore, the modulator valve reduces (adjusts) the line pressure PL from the oil passage L1 to generate a substantially constant modulator pressure.

[0028] The linear solenoid valves SL1-SL5 have a common configuration and include an electromagnetic part that is energized and controlled by the TMECU 21, a spool that is axially movably disposed within a sleeve held by the valve body 600, a spring that biases the spool toward the electromagnetic part, an input port that communicates with oil passage L1 of the valve body 600 via oil passage L2 or oil passage L3, an output port, a feedback port that communicates with the output port, and a drain port. In this embodiment, the linear solenoid valves SL1-SL5 are normally closed valves that open when current is supplied to the electromagnetic part, and adjust the line pressure PL that is supplied to the input port as the source pressure in accordance with the current applied to the electromagnetic part and output it from the output port. That is, in the linear solenoid valves SL1-SL5, the pressure of the hydraulic oil supplied to the input port (line pressure PL) is adjusted to the desired pressure by balancing the thrust generated by supplying power to the electromagnetic part (coil), the spring force, and the thrust toward the electromagnetic part acting on the spool due to the hydraulic pressure supplied from the output port to the feedback port.

[0029] In this embodiment, linear solenoid valve SL1 adjusts line pressure PL to generate hydraulic pressure for clutch C1, and linear solenoid valve SL2 adjusts line pressure PL to generate hydraulic pressure Psl2 for clutch C2 and brake B2. Furthermore, linear solenoid valve SL3 adjusts line pressure PL to generate hydraulic pressure for clutch C3, linear solenoid valve SL4 adjusts line pressure PL to generate hydraulic pressure for clutch C4, and linear solenoid valve SL5 adjusts line pressure PL to generate hydraulic pressure for brake B1. In other words, linear solenoid valves SL1, SL3-SL5 are dedicated pressure regulating valves that generate hydraulic pressure for one corresponding hydraulic engagement element, and linear solenoid valve SL2 is a shared pressure regulating valve that corresponds to both clutch C2 and brake B2. In addition, in this embodiment, the input ports of linear solenoid valves SL1, SL2, SL4 and SL5 corresponding to clutches C1, C2, C4 and brake B1, which are engaged only when forward first gear to eighth gear (forward stage) are formed, are connected to oil passage L1 via first switching valve 100 and oil passage L3, and the input port of linear solenoid valve SL3 is connected to oil passage L1 via oil passage L2.

[0030] The first signal pressure output valve SC1 is, for example, a normally closed on-off solenoid valve that is energized and controlled by the TMECU 21, and an input port of the first signal pressure output valve SC1 communicates with an oil passage L1 formed in the valve body 600 or an output port of a modulator valve. When current is supplied to an electromagnetic part, the first signal pressure output valve SC1 causes the line pressure PL or modulator pressure, which is supplied to the input port as a source pressure, to flow from the output port as a first signal pressure Psc1.

[0031] The second signal pressure output valve SC2 is also, for example, a normally closed on / off solenoid valve that is energized and controlled by the TMECU 21, and the input port of the second signal pressure output valve SC2 communicates with an oil passage L1 formed in the valve body 600 or an output port of a modulator valve. When current is supplied to the electromagnetic part, the second signal pressure output valve SC2 causes the source pressure (line pressure PL or modulator pressure) common to the first signal pressure output valve SC1, supplied to the input port, to flow out from the output port as a second signal pressure Psc2.

[0032] The third signal pressure output valve SC3 is also, for example, a normally closed on-off solenoid valve that is energized and controlled by the TMECU 21, and the input port of the third signal pressure output valve SC3 communicates with an oil passage L1 formed in the valve body 600 or an output port of a modulator valve. When current is supplied to the electromagnetic part, the third signal pressure output valve SC3 causes the source pressure (line pressure PL or modulator pressure) that is supplied to the input port and is common to the first and second signal pressure output valves SC1, SC2, to flow out from the output port as a third signal pressure Psc3.

[0033] The first switching valve 100 is a spool valve including a first spool S1 having a plurality of lands and arranged axially movably within the valve body 600, and a first spring SP1 that urges the first spool S1 upward in Fig. 4. Furthermore, the first switching valve 100 includes a source pressure input port 101, a first source pressure output port 103, a second source pressure output port 104, a first signal pressure input port 105, a holding pressure input port 106, a first inlet port 107, a first outlet port 108, a second inlet port 109, and a second outlet port 110.

[0034] The source pressure input port 101 of the first switching valve 100 communicates with an oil passage L1 in the valve body 600. The first source pressure output port 103 communicates with an oil passage L3 formed in the valve body 600, and the second source pressure output port 104 communicates with an oil passage L4 formed in the valve body 600. The first signal pressure input port 105 is located on the opposite side of the spring chamber in which the first spring SP1 is disposed and communicates with an output port of the first signal pressure output valve SC1 via an oil passage L5 formed in the valve body 600. The holding pressure input port 106 communicates with the spring chamber in which the first spring SP1 is disposed and also communicates with an oil passage L6 formed in the valve body 600. The first inlet port 107 communicates with an output port of the second signal pressure output valve SC2 via an oil passage L7 formed in the valve body 600, and the first outlet port 108 communicates with an oil passage L8 formed in the valve body 600. The oil passage L6, which communicates with the holding pressure input port 106, branches off from the oil passage L8. As a result, the holding pressure input port 106 communicates with the first outflow port 108 via the oil passage L6 and a part of the oil passage L8. Furthermore, the second inflow port 109 communicates with the output port of the third signal pressure output valve SC3 via an oil passage L9 formed in the valve body 600, and the second outflow port 110 communicates with an oil passage L10 formed in the valve body 600.

[0035] In this embodiment, the installed state of the first switching valve 100 is a first state (the state of the left half in FIG. 4 ) in which the first spool S1 is urged upward in FIG. 4 by the first spring SP1 without the first or second signal pressure Psc1, Psc2 from the first or second signal pressure output valve SC1, SC2 being supplied to the first signal pressure input port 105 and the holding pressure input port 106. In the first state (installed state) of the first switching valve 100, the first spool S1 communicates between the main pressure input port 101 and the first main pressure output port 103 and blocks communication between the main pressure input port 101 and the second main pressure output port 104. Furthermore, in the first state, the first spool S1 communicates between the first inlet port 107 and the first outlet port 108 and blocks communication between the second inlet port 109 and the second outlet port 110.

[0036] Furthermore, when the first switching valve 100 is in the first state, if current is supplied to the electromagnetic part of the second signal pressure output valve SC2, the hydraulic oil (second signal pressure Psc2) from the second signal pressure output valve SC2 flows into the first inlet port 107 via the oil passage L7 and flows out to the oil passage L8 via the first outlet port 108. Furthermore, a portion of the hydraulic oil from the second signal pressure output valve SC2 flows into the holding pressure input port 106 via the oil passages L8 and L6. As a result, the second signal pressure Psc2 from the second signal pressure output valve SC2 acts on the pressure-receiving surface of the first spool S1 on the side of the first spring SP1, and the first switching valve 100 is in the first state. Furthermore, in this embodiment, the pressure-receiving surface of the first spool S1 on the side of the first signal pressure input port 105 and the pressure-receiving surface on the side of the holding pressure input port 106 (first spring SP1) have the same area. Therefore, when the first switching valve 100 forms the first state and the second signal pressure output valve SC2 outputs the second signal pressure Psc2, even if the first signal pressure Psc1 from the first signal pressure output valve SC1 is supplied to the first signal pressure input port 105, the first switching valve 100 continues to form the first state.

[0037] On the other hand, when the second signal pressure Psc2 from the second signal pressure output valve SC2 is not supplied to the holding pressure input port 106 and the first signal pressure Psc1 from the first signal pressure output valve SC1 is supplied to the first signal pressure input port 105, the first spool S1 moves downward in Fig. 4 against the biasing force of the first spring SP1 due to a thrust acting on the first spool S1 by the first signal pressure Psc1, and the first changeover valve 100 is in the second state (the state of the right half in Fig. 4). In the second state of the first changeover valve 100, the first spool S1 blocks communication between the main pressure input port 101 and the first main pressure output port 103 and connects the main pressure input port 101 and the second main pressure output port 104. Furthermore, in the second state, the first spool S1 blocks communication between the first inflow port 107 and the first outflow port 108, and allows communication between the second inflow port 109 and the second outflow port 110.

[0038] The second switching valve 200 is a spool valve including a second spool S2 having a plurality of lands and arranged axially movably within the valve body 600, and a second spring SP2 that biases the second spool S2 upward in Fig. 4. Furthermore, the second switching valve 200 includes a first input port 201, a second input port 202, a first output port 203, a second output port 204, a second signal pressure input port 205, an inlet port 209, and an outlet port 210.

[0039] The first input port 201 of the second switching valve 200 communicates with the output port of the linear solenoid valve SL2 via an oil passage L11 formed in the valve body 600, and the second input port 202 communicates with the second source pressure output port 104 of the first switching valve 100 via an oil passage L4 in the valve body 600. The first output port 203 communicates with the engagement oil chamber of the clutch C2 via an oil passage L13 formed in the valve body 600, and the second output port 204 communicates with an oil passage L14 formed in the valve body 600. Furthermore, the second signal pressure input port 205 is disposed on the opposite side of the spring chamber in which the second spring SP2 is disposed, and communicates with the output port of the second signal pressure output valve SC2 via an oil passage L15 formed in the valve body 600. The inlet port 209 is connected to the second outlet port 110 of the first switching valve 100 via the oil passage L10 of the valve body 600, and the outlet port 210 is connected to the hydraulic inlet of the shift-by-wire parking lock mechanism 70 via the oil passage L16 formed in the valve body 600.

[0040] In this embodiment, the attached state of the second switching valve 200 is a first supply state (the state of the left half in FIG. 4 ) in which the second signal pressure Psc2 from the second signal pressure output valve SC2 is not supplied to the second signal pressure input port 205 and the second spool S2 is urged upward in FIG. 4 by the second spring SP2. In the first supply state (attached state) of the second switching valve 200, the second spool S2 communicates between the first input port 201 and the second output port 204 and blocks communication between the first input port 201 and the first output port 203 and between the second input port 202 and the second output port 204. Furthermore, in the first supply state, the second spool S2 communicates between the inlet port 209 and the outlet port 210.

[0041] On the other hand, when the second signal pressure Psc2 is supplied from the second signal pressure output valve SC2 to the second signal pressure input port 205, the second spool S2 moves downward in FIG. 4 against the biasing force of the second spring SP2 due to a thrust acting on the second spool S2 by the second signal pressure Psc2, and the second switching valve 200 is in the second supply state (the state of the right half in FIG. 4). In the second supply state of the second switching valve 200, the second spool S2 communicates between the first input port 201 and the first output port 203 and also communicates between the second input port 202 and the second output port 204. Furthermore, in the second supply state, the second spool S2 blocks communication between the inlet port 209 and the outlet port 210.

[0042] The third switching valve 300 is a spool valve including a third spool S3 having a plurality of lands and arranged axially movably within the valve body 600, and a third spring SP3 that urges the third spool S3 upward in Fig. 4. Furthermore, the third switching valve 300 includes a third input port 301, a third output port 303, a third signal pressure input port 305, and a holding pressure input port 306.

[0043] The third input port 301 of the third changeover valve 300 communicates with the second output port 204 of the second changeover valve 200 via an oil passage L14 formed in the valve body 600. The third output port 303 communicates with the engagement oil chamber of the brake B2 via an oil passage L17 formed in the valve body 600, etc. The third signal pressure input port 305 is disposed on the opposite side of the spring chamber in which the third spring SP3 is disposed, and communicates with the first outflow port 108 of the first changeover valve 100 via the oil passage L8 of the valve body 600. The holding pressure input port 306 communicates with the output port of the third signal pressure output valve SC3 via an oil passage L18 formed in the valve body 600.

[0044] In this embodiment, the attached state of the third switching valve 300 is a supply state (the state of the left half in FIG. 4) in which the second signal pressure Psc2 from the second signal pressure output valve SC2 is not supplied to the third signal pressure input port 305 via the first inflow port 107 and the first outflow port 108 of the first switching valve 100, and the third spool S3 is urged upward in FIG. 4 by the third spring SP3. In the supply state (attached state) of the third switching valve 300, the third spool S3 communicates between the third input port 301 and the third output port 303.

[0045] On the other hand, when the second signal pressure Psc2 from the second signal pressure output valve SC2 is supplied to the third signal pressure input port 305 via the first inflow port 107 and the first outflow port 108 of the first switching valve 100, the third spool S3 moves downward in FIG. 4 against the biasing force of the third spring SP3 due to a thrust force acting on the third spool S3 due to the second signal pressure Psc2, and the third switching valve 300 is in the shut-off state (the state of the right half in FIG. 4). When the third switching valve 300 is in the shut-off state, the third spool S3 shuts off communication between the third input port 301 and the third output port 303.

[0046] Next, the operation of the hydraulic control device 60 will be described with reference to FIGS.

[0047] When the ignition switch (start switch) of the vehicle 10 is turned on with the shift lever 95 set to the parking position, the TMECU 21 supplies current to the electromagnetic parts of the first and third signal pressure output valves SC1, SC3 so that the first and third signal pressures Psc1, Psc3 are output, as shown in Fig. 5. As a result, as shown in Fig. 6, the first switching valve 100 establishes the second state, whereby the main pressure input port 101 and the second main pressure output port 104 communicate with each other and the second inflow port 109 and the second outflow port 110 communicate with each other. Furthermore, because the second signal pressure Psc2 is not output from the second signal pressure output valve SC2, the second switching valve 200 establishes the first supply state, whereby the first input port 201 and the second output port 204 communicate with each other and the inflow port 209 and the outflow port 210 communicate with each other. Furthermore, since the second signal pressure Psc2 from the second signal pressure output valve SC2 is not supplied to the third signal pressure input port 305 via the first switching valve 100, the third switching valve 300 forms the above-mentioned supply state, and the third input port 301 and the third output port 303 are connected.

[0048] Therefore, when the shift lever 95 is set to the parking position, as shown in FIG. 6, the third signal pressure Psc3 from the third signal pressure output valve SC3 is supplied to the parking lock mechanism 70 via the first switching valve 100 (the second inlet port 109 and the second outlet port 110) and the second switching valve 200 (the inlet port 209 and the outlet port 210), thereby establishing a parking lock state. Furthermore, when the shift lever 95 is set to the parking position, hydraulic oil (line pressure PL) from the primary regulator valve flows from the oil passage L1 of the valve body 600 into the oil passage L4 via the first switching valve 100 (the source pressure input port 101 and the second source pressure output port 104). However, at this time, because the second switching valve 200 establishes the first supply state, the line pressure PL is not supplied to the engagement oil chamber of the brake B2 via the third switching valve 300 (the third input port 301 and the third output port 303). In addition, when the shift lever 95 is set to the neutral position, the TMECU 21 supplies current to the electromagnetic part of the first signal pressure output valve SC1 so that the first signal pressure Psc1 is output, and also de-energizes the second and third signal pressure output valves SC2, SC3.

[0049] On the other hand, when the driver sets the shift lever 95 to the reverse position, the TMECU 21 supplies current to the electromagnetic parts of the first, second, and third signal pressure output valves SC1, SC2, and SC3 so that all of the first, second, and third signal pressures Psc1, Psc2, and Psc3 are output, as shown in Fig. 5. At this time, the TMECU 21 supplies current to the electromagnetic parts of the first, second, and third signal pressure output valves SC1, SC2, and SC3 so that the second or third signal pressures Psc2, Psc3 are output from the second and third signal pressure output valves SC2, SC3 after the first signal pressure Psc1 is supplied from the first signal pressure output valve SC1 to the first signal pressure input port 105 of the first switching valve 100.

[0050] 7, the first switching valve 100 establishes the second state, whereby the source pressure input port 101 and the second source pressure output port 104 communicate with each other, and the second inlet port 109 and the second outlet port 110 communicate with each other. Furthermore, when the second signal pressure Psc2 is output from the second signal pressure output valve SC2, the second switching valve 200 establishes the second supply state, whereby the second input port 202 and the second output port 204 communicate with each other. Furthermore, since the communication between the first inlet port 107 and the first outlet port 108 is blocked by the first switching valve 100 establishing the second state, the second signal pressure Psc2 from the second signal pressure output valve SC2 is not supplied to the third signal pressure input port 305, and the third switching valve 300 establishes the supply state where the third input port 301 and the third output port 303 communicate with each other.

[0051] Therefore, when the shift lever 95 is set to the reverse position, hydraulic oil (line pressure PL) from the primary regulator valve side is supplied from oil passage L1 of the valve body 600 to the main pressure input port 101 and the second main pressure output port 104 of the first selector valve 100, oil passage L4, the second input port 202 and the second output port 204 of the second selector valve 200, oil passage L14, the third input port 301 and the third output port 303 of the third selector valve 300, oil passage L17, etc., and then to the engagement oil chamber of the brake B2. Furthermore, hydraulic oil (line pressure PL) from the primary regulator valve side is supplied to the input port of the linear solenoid valve SL3 via oil passages L1 and L2, and the hydraulic oil whose pressure is adjusted by the linear solenoid valve SL3 is supplied to the engagement oil chamber of the clutch C3. This engages the clutch C3 and the brake B2, thereby achieving first reverse gear. Furthermore, when the shift lever 95 is set to the reverse position, the third signal pressure Psc3 from the third signal pressure output valve SC3 is supplied to the oil passage L10 via the second inlet port 109 and the second outlet port 110 of the first changeover valve 100. However, at this time, the second changeover valve 200 establishes the second supply state, so the third signal pressure Psc3 is not supplied to the parking lock mechanism 70 via the second changeover valve 200, and the third signal pressure Psc3 is supplied only to the holding pressure input port 306 of the third changeover valve 300 as a holding pressure.

[0052] Furthermore, when the driver sets the shift lever 95 to the drive position or sport position (forward drive position), the TMECU 21 de-energizes the electromagnetic units of the first, second, and third signal pressure output valves SC1, SC2, and SC3 to stop the output of all of the first, second, and third signal pressures Psc1, Psc2, and Psc3, as shown in Fig. 5. As a result, as shown in Fig. 8, the first changeover valve 100 establishes the first state, where the main pressure input port 101 and the first main pressure output port 103 communicate with each other and the first inflow port 107 and the first outflow port 108 communicate with each other. Furthermore, because the second signal pressure output valve SC2 does not output the second signal pressure Psc2, the second changeover valve 200 establishes the first supply state, where the first input port 201 and the second output port 204 communicate with each other and the inflow port 209 and the outflow port 210 communicate with each other. Furthermore, since the second signal pressure Psc2 is not output from the second signal pressure output valve SC2, the third switching valve 300 establishes the above-mentioned supply state, and the third input port 301 and the third output port 303 communicate with each other.

[0053] Therefore, when the shift lever 95 is set to a forward drive position such as the drive position, hydraulic oil (line pressure PL) from the primary regulator valve is supplied from the oil passage L1 of the valve body 600 to the input ports of the linear solenoid valves SL1, SL2, SL4, and SL5 corresponding to the clutches C1, C2, and C4 and the brake B1, which are engaged only when the forward gear is established, via the oil passage L3, the first source pressure input port 101, the first source pressure output port 103 of the first selector valve 100, etc. Hydraulic oil whose pressure is adjusted by the linear solenoid valve SL1 is supplied to the engagement oil chamber of the clutch C1. Hydraulic oil (hydraulic pressure Psl2) whose pressure is adjusted by the linear solenoid valve SL2 is supplied to the engagement oil chamber of the brake B2 via the oil passage L11, the first input port 201 and the second output port 204 of the second selector valve 200, the oil passage L14, the third input port 301 and the third output port 303 of the third selector valve 300, the oil passage L17, etc. This allows the clutch C1 and the brake B2 to be engaged to form the first forward speed.

[0054] Furthermore, when an upshift condition for upshifting the gear to second forward speed or the like is satisfied while the first forward speed is established, the TMECU 21 supplies current to the electromagnetic parts of the second signal pressure output valve SC2 while de-energizing the electromagnetic parts of the first and third signal pressure output valves SC1, SC3, as shown in Fig. 5. As a result, as shown in Fig. 9, the first changeover valve 100 establishes the first state, whereby the main pressure input port 101 and the first main pressure output port 103 communicate with each other and the first inlet port 107 and the first outlet port 108 communicate with each other. Furthermore, as a result of the second signal pressure Psc2 being output from the second signal pressure output valve SC2, the second changeover valve 200 establishes the second supply state, whereby the first input port 201 and the first output port 203 communicate with each other and the second input port 202 and the second output port 204 communicate with each other. Furthermore, the second signal pressure Psc2 from the second signal pressure output valve SC2 is supplied to the third signal pressure input port 305 via the first inlet port 107 and the first outlet port 108 of the first switching valve 100 and the oil passage L8, and the third switching valve 300 forms the above-mentioned blocked state in which communication between the third input port 301 and the third output port 303 is blocked.

[0055] As a result, hydraulic oil (line pressure PL) from the primary regulator valve side is supplied from oil passage L1 of valve body 600 via oil passage L3 and the like to input ports of linear solenoid valves SL1, SL2, SL4, and SL5 corresponding to clutches C1, C2, C4 and brake B1, which are engaged only when a forward gear is established, through oil passage L3. The input port of linear solenoid valve SL3 is also connected to oil passage L1 via oil passage L2. Therefore, depending on the vehicle speed and accelerator pedal position of vehicle 10, hydraulic pressure from two of linear solenoid valves SL1-SL5 can be used to engage any two of clutches C1-C4 and brake B1 to establish a desired gear from second forward gear to eighth forward gear.

[0056] 10, the second changeover valve 200 may enter a first supply state that allows hydraulic pressure Psl2 to be supplied from the linear solenoid valve SL2 to the brake B2 (second hydraulic engagement element), even though the second signal pressure Psc2 from the second signal pressure output valve SC2 is being supplied to the second signal pressure input port 205. Furthermore, the fifth to eighth forward speeds of the automatic transmission 25 are achieved by engaging the clutch C2 (first engagement element) with one of the clutches C1, C3, C4, and the brake B1. However, if the second changeover valve 200, which should enter the second supply state when one of the fifth to eighth forward speeds should be achieved, enters the first supply state and hydraulic pressure Psl2 from the linear solenoid valve SL2 is supplied to the brake B2, a gear other than the fifth to eighth forward speeds will be achieved.

[0057] That is, when the fifth forward gear is to be implemented, if the second selector valve 200 is in the first supply state and hydraulic pressure Psl2 from the linear solenoid valve SL2 is supplied to the brake B2, there is a risk that the first forward gear will be implemented and the vehicle 10 will suddenly decelerate, as can be seen from Fig. 3. Also, when the sixth forward gear is to be implemented, if the second selector valve 200 is in the first supply state and hydraulic pressure Psl2 from the linear solenoid valve SL2 is supplied to the brake B2, there is a risk that the second reverse gear will be implemented, as can be seen from Fig. 3. Furthermore, when the seventh forward gear is to be implemented, if the second selector valve 200 is in the first supply state and hydraulic pressure Psl2 from the linear solenoid valve SL2 is supplied to the brake B2, there is a risk that the first reverse gear will be implemented, as can be seen from Fig. 3.

[0058] In consideration of these, in the hydraulic control device 60, when any of second forward speed to eighth forward speed is established, the second signal pressure Psc2 from the second signal pressure output valve SC2 is supplied to the third signal pressure input port 305 of the third changeover valve 300 via the first inlet port 107 and the first outlet port 108 of the first changeover valve 100 and the oil passage L8. As a result, as shown in Fig. 10, the third changeover valve 300 establishes the above-mentioned blocked state in which communication between the third input port 301 and the third output port 303 is blocked. As a result, even if the second changeover valve 200 establishes the first supply state when any of fifth forward speed to eighth forward speed should be established, the hydraulic pressure Psl2 from the linear solenoid valve SL2 is not supplied to the brake B2, and the automatic transmission 25 can be placed in the neutral state.

[0059] On the other hand, if an abnormality occurs such that the second signal pressure Psc2 is no longer output from the second signal pressure output valve SC2 when any of the forward fifth speed through the forward eighth speed should be established, the second changeover valve 200 will establish the first supply state in which the biasing force of the second spring SP2 connects the first input port 201 and the second output port 204, and the third changeover valve 300 will establish the supply state in which the biasing force of the third spring SP3 connects the third input port 301 and the third output port 303, as shown in Fig. 11. For this reason, if the second signal pressure Psc2 is no longer output from the second signal pressure output valve SC2 when any of the forward fifth speed through the forward eighth speed should be established, the hydraulic pressure Psl2 from the linear solenoid valve SL2 will be supplied to the brake B2 via the second and third changeover valves 200, 300, which could result in a gear other than the forward fifth speed through the forward eighth speed being established. Based on this, when the fifth forward gear to the eighth forward gear are formed, the TMECU 21 supplies current to the electromagnetic part of the first signal pressure output valve SC1 so that the first signal pressure Psc1 is supplied to the first signal pressure input port 105 of the first switching valve 100 while the second signal pressure Psc2 from the second signal pressure output valve SC2 is supplied to the holding pressure input port 106 of the first switching valve 100.

[0060] That is, while the fifth forward speed through the eighth forward speed are established, the first signal pressure Psc1 from the first signal pressure output valve SC1 acts on the pressure-receiving surface of the first spool S1 opposite to the first spring SP1 side, but the second signal pressure Psc2 from the second signal pressure output valve SC2 acts on the pressure-receiving surface of the first spool S1 on the first spring SP1 side, causing the first changeover valve 100 to establish the second state as when the second forward speed through the fourth forward speed are established. On the other hand, if the second signal pressure Psc2 is no longer output from the second signal pressure output valve SC2 due to the occurrence of some abnormality when one of the fifth forward speed through the eighth forward speed should be established, the thrust acting on the first spool S1 by the first signal pressure Psc1 from the first signal pressure output valve SC1 overcomes the biasing force of the first spring SP1, causing the first changeover valve 100 to establish the second state as shown in FIG.

[0061] As a result, communication between the source pressure input port 101 and the second source pressure output port 104 allows the supply of line pressure PL to the second changeover valve 200 (brake B2) side, and blocking communication between the source pressure input port 101 and the first source pressure output port 103 cuts off the supply of line pressure PL to the input ports of the linear solenoid valves SL1, SL2, SL4, and SL5 corresponding to the clutches C1, C2, C4 and brake B1 that are engaged only when a forward gear is established. Also, the second changeover valve 200, which no longer receives the supply of second signal pressure Psc2, allows the supply of hydraulic pressure Psl2 from the linear solenoid valve SL2 to the brake B2 side, and restricts the supply of line pressure PL from the first changeover valve 100 to the brake B2 side. Therefore, even if the third switching valve 300, which no longer receives the supply of the second signal pressure Psc2, allows the supply of hydraulic pressure Psl2 from the linear solenoid valve SL2 from the second switching valve 200 to the brake B2, the supply of line pressure PL (original pressure) to the linear solenoid valve SL2 is cut off and hydraulic pressure is no longer supplied from the linear solenoid valve SL2 to the brake B2, so the automatic transmission 25 can be placed in a neutral state.

[0062] As described above, in the hydraulic control device 60 of the present disclosure, the hydraulic pressure Psl2 generated (adjusted) by the linear solenoid valve SL2 (dual-purpose pressure regulating valve) can be supplied to the clutch C2 (first hydraulic engagement element) and the brake B2 (second hydraulic engagement element) that is engaged when at least the first reverse gear and the second reverse gear of the automatic transmission 25 are established but is not simultaneously engaged with the clutch C2. This makes it possible to reduce the number of linear solenoid valves (pressure regulating valves) in the hydraulic control device 60, thereby reducing costs by reducing the number of linear solenoid valves and improving efficiency by reducing oil leakage.

[0063] Furthermore, when any of the forward fifth speed through the forward eighth speed (forward gears) is established, the first changeover valve 100 receives both the first signal pressure Psc1 from the first signal pressure output valve SC1 and the second signal pressure Psc2 from the second signal pressure output valve SC2. As a result, the first changeover valve 100 allows the supply of line pressure PL as the source pressure to the linear solenoid valves SL1, SL2, SL4, and SL5 corresponding to the clutches C1, C2, and C4 and the brake B1, which are engaged only when the forward first speed through the forward eighth speed (forward gears) are established, and also allows the outflow of hydraulic oil (second signal pressure Psc2) supplied from the second signal pressure output valve SC2. At this time, the third changeover valve 300 receives the second signal pressure Psc2 from the second signal pressure output valve SC2 via the first changeover valve 100 and regulates the supply of hydraulic pressure Psl2 from the linear solenoid valve SL2 to the brake B2 from the second changeover valve 200. As a result, when the first switching valve 100 allows the linear solenoid valve SL2 to be supplied with line pressure PL as the base pressure, even if the second switching valve 200 allows the linear solenoid valve SL2 to supply oil pressure Psl2 to the brake B2 side due to an abnormality such as sticking, even though it is receiving the second signal pressure Psc2 from the second signal pressure output valve SC2, it is possible to prevent the oil pressure Psl2 from the linear solenoid valve SL2 from being supplied to the brake B2, thereby putting the automatic transmission 25 into a neutral state.

[0064] Furthermore, if the second signal pressure Psc2 is no longer output from the second signal pressure output valve SC2 due to some abnormality when any of the fifth to eighth forward speeds is established, the first changeover valve 100 receives only the first signal pressure Psc1, thereby allowing the supply of line pressure PL to the brake B2 (second changeover valve 200) and restricting the supply of line pressure PL to the linear solenoid valves SL1, SL2, SL4, and SL5 corresponding to the clutches C1, C2, and C4 and brake B1 that are engaged only when a forward gear is established. Therefore, even if the third changeover valve 300, which no longer receives the supply of second signal pressure Psc2, allows the supply of hydraulic pressure Psl2 from the linear solenoid valve SL2 to the brake B2 from the second changeover valve 200 to the brake B2, the supply of line pressure PL to the linear solenoid valve SL2 is cut off and hydraulic pressure is no longer supplied from the linear solenoid valve SL2 to the brake B2, so the automatic transmission 25 can be placed in the neutral state.

[0065] As a result, the hydraulic control device 60 can selectively supply hydraulic pressure Psl2 to the clutch C2 and the brake B2 from one linear solenoid valve SL2, thereby reducing costs and improving efficiency while ensuring a fail-safe. However, the hydraulic control device 60 may also be applied to a transmission that provides multiple gears by selectively engaging three or more hydraulic engagement elements.

[0066] Furthermore, in the automatic transmission 25, the clutch C2 is engaged when a plurality of low forward gears including the start gear are established, i.e., when forward fifth gear through forward eighth gear, which are higher than forward first gear through forward fourth gear, are established, and the brake B2 is engaged when reverse first gear and reverse second gear are established and when forward first gear, which is the start gear, is established. By applying the hydraulic control device 60 to this automatic transmission 25, it is possible to selectively supply hydraulic pressure Psl2 from one linear solenoid valve SL2 to the clutch C2 and the brake B2, which is not simultaneously engaged with the clutch C2, and to ensure a good fail-safe when the high speed gears of the automatic transmission 25, i.e., forward fifth gear through forward eighth gear, are established.

[0067] Furthermore, in the first switching valve 100, when the first signal pressure Psc1 is not supplied to the first signal pressure input port 105, and when the first signal pressure Psc1 is supplied to the first signal pressure input port 105 and the second signal pressure Psc2 is supplied to the holding pressure input port 106 via the first inlet port 107 and the first outlet port 108, the first spool S1 forms a first state in which the biasing force of the first spring SP1 causes the main pressure input port 101 to communicate with the first main pressure output port 103 and also causes the first inlet port 107 to communicate with the first outlet port 108. In the first switching valve 100, when the first signal pressure Psc1 is supplied to the first signal pressure input port 105, the first spool S1 establishes a second state in which the first spool S1 communicates between the main pressure input port 101 and the second main pressure output port 104 against the biasing force of the first spring SP1 and blocks communication between the first inlet port 107 and the first outlet port 108. Furthermore, in the second switching valve 200, when the second signal pressure Psc2 is not supplied to the second signal pressure input port 205, the second spool S2 establishes a first supply state in which the second spool S2 communicates between the first input port 201 and the second output port 204 and blocks communication between the second input port 202 and the second output port 204 by the biasing force of the second spring SP2. In the second switching valve 200, when the second signal pressure Psc2 is supplied to the second signal pressure input port 205, the second spool S2 establishes a second supply state in which the first input port 201 communicates with the first output port 203 and the second input port 202 communicates with the second output port 204 against the biasing force of the second spring SP2. Furthermore, in the third switching valve 300, when the second signal pressure Psc2 is not supplied to the third signal pressure input port 305 from the first outlet port 108 of the first switching valve 100, the third spool S3 establishes a supply state in which the third input port 301 communicates with the third output port 303 by the biasing force of the third spring SP3. In addition, in the third switching valve 300, when the second signal pressure Psc2 is supplied to the third signal pressure input port 305 from the first outlet port 108 of the first switching valve 100, the third spool S3 forms a blocked state in which the communication between the third input port 301 and the third output port 303 is blocked against the biasing force of the third spring SP3.As a result, when an abnormality occurs in the second switching valve 200 or the second signal pressure output valve SC2, the automatic transmission 25 can be placed in the neutral state, thereby ensuring a good fail-safe.

[0068] 12 is a system diagram showing the main parts of another hydraulic control device 60B of the present disclosure that can be applied to the above-described power transmission device 20. Among the components of the hydraulic control device 60B, the same elements as those of the above-described hydraulic control device 60 are designated by the same reference numerals, and redundant explanations will be omitted. The hydraulic control device 60B is also connected to the above-described mechanical oil pump 24 that is capable of drawing and discharging hydraulic oil from a hydraulic oil reservoir in the transaxle case 22b through a strainer. The hydraulic control device 60B is also controlled by the TMECU 21, and generates hydraulic oil pressure required by the starting device 23 and the automatic transmission 25, and supplies hydraulic oil to low-pressure oil supply parts (lubricated parts) such as various bearings and other lubrication targets and the centrifugal hydraulic cancel chambers of the clutches C1-C4. As shown in the figure, the hydraulic control device 60B includes a valve body 600B in which a plurality of oil passages and the like are formed, a primary regulator valve, a secondary regulator valve, and a modulator valve (none of which are shown), linear solenoid valves SL1, SL2, SL3, SL4, and SL5, a first signal pressure output valve SC1, a second signal pressure output valve SC2, a third signal pressure output valve SC3, a first changeover valve 100B, a second changeover valve 200B, and a third changeover valve 300B. The hydraulic control device 60B also does not have a manual valve linked to the shift lever 95, and constitutes a shift-by-wire device together with the TMECU 21. In other words, the TMECU 21 controls the hydraulic control device 60B so that the automatic transmission 25 is in a state corresponding to the shift position of the shift lever 95 set by the driver.

[0069] The valve body 600B is attached to, for example, a side portion of the transaxle case 22b that constitutes the transmission case 22. A primary regulator valve (not shown) of the hydraulic control device 60B adjusts the pressure of the hydraulic oil supplied from the mechanical oil pump 24 to an oil passage L21 of the valve body 600B, i.e., the line pressure PL, in accordance with a signal pressure supplied from a linear solenoid valve (not shown). The secondary regulator valve adjusts the pressure of the hydraulic oil drained from the primary regulator valve in accordance with the signal pressure from the linear solenoid valve, generating a secondary pressure (circulation pressure) that is lower than the line pressure PL. Furthermore, the modulator valve reduces (adjusts) the line pressure PL from the oil passage L1 to generate a substantially constant modulator pressure Pmod.

[0070] In the hydraulic control device 60B, linear solenoid valves SL1, SL3-SL5 are dedicated pressure regulating valves that generate hydraulic pressure for the corresponding clutches C1, C3, C4 or brake B1, respectively, and linear solenoid valve SL2 is a dual-purpose pressure regulating valve that corresponds to both clutch C2 and brake B2. In addition, in the hydraulic control device 60B, the input ports of linear solenoid valves SL1, SL4, and SL5 that correspond to clutches C1, C4 or brake B1, which are engaged only when forward first through eighth gears (forward stages) are established, communicate with oil passage L21 via first selector valve 100 and oil passage L22. Furthermore, the input port of linear solenoid valve SL2 communicates with oil passage L21 via oil passage L23, and the input port of linear solenoid valve SL3 communicates with oil passage L21 via oil passage L24.

[0071] The first signal pressure output valve SC1 is, for example, a normally closed on-off solenoid valve that is energized and controlled by the TMECU 21. When current is supplied to its electromagnetic part, it causes the line pressure PL or modulator pressure, which is the source pressure supplied to its input port, to flow from its output port as a first signal pressure Psc1. The second signal pressure output valve SC2 is also, for example, a normally closed on-off solenoid valve that is energized and controlled by the TMECU 21. When current is supplied to its electromagnetic part, it causes the source pressure (line pressure PL or modulator pressure) common to the first signal pressure output valve SC1 to flow from its output port as a second signal pressure Psc2. The third signal pressure output valve SC3 is also, for example, a normally closed on-off solenoid valve that is energized and controlled by the TMECU 21. When current is supplied to its electromagnetic part, it causes the source pressure (line pressure PL or modulator pressure) common to the first and second signal pressure output valves SC1 and SC2 to flow from its output port as a third signal pressure Psc3.

[0072] The first switching valve 100B is a spool valve including a first spool S1 that has a plurality of lands and is arranged axially movably within the valve body 600B, and a first spring SP1 that urges the first spool S1 upward in Fig. 12. Furthermore, the first switching valve 100B includes a source pressure input port 101, a source pressure output port 102, a first signal pressure input port 105, a holding pressure input port 106, an inlet port 111, an outlet port 112, and a parking port 117.

[0073] The source pressure input port 101 of the first switching valve 100B communicates with the oil passage L21 of the valve body 600B, and the source pressure output port 102 communicates with the oil passage L22 formed in the valve body 600B. The first signal pressure input port 105 is located on the opposite side of the spring chamber in which the first spring SP1 is disposed and communicates with the output port of the first signal pressure output valve SC1 via the oil passage L25 formed in the valve body 600B. The holding pressure input port 106 communicates with the spring chamber in which the first spring SP1 is disposed and also communicates with the oil passage L26 formed in the valve body 600B. The inlet port 111 communicates with the output port of the second signal pressure output valve SC2 via the oil passage L27 formed in the valve body 600B, and the outlet port 112 communicates with the oil passage L28 formed in the valve body 600B. The oil passage L26, which communicates with the holding pressure input port 106, branches off from the oil passage L28. As a result, the holding pressure input port 106 communicates with the outflow port 112 via the oil passage L26 and a part of the oil passage L28. Furthermore, the parking port 117 communicates with the hydraulic inlet of the shift-by-wire parking lock mechanism 70 via an oil passage formed in the valve body 600B.

[0074] In the hydraulic control device 60B, the installation state of the first switching valve 100B is a first state (the state of the left half in FIG. 12) in which the first spool S1 is urged upward in FIG. 12 by the first spring SP1 without the first or second signal pressure Psc1, Psc2 from the first or second signal pressure output valve SC1, SC2 being supplied to the first signal pressure input port 105 and the holding pressure input port 106. In the first state (installed state) of the first switching valve 100B, the first spool S1 communicates between the source pressure input port 101 and the source pressure output port 102, and also communicates between the inlet port 111 and the outlet port 112.

[0075] Furthermore, when the first switching valve 100B is in the first state, if current is supplied to the electromagnetic part of the second signal pressure output valve SC2, the hydraulic oil (second signal pressure Psc2) from the second signal pressure output valve SC2 flows into the inlet port 111 via the oil passage L27 and flows out to the oil passage L28 via the outlet port 112. Furthermore, a portion of the hydraulic oil from the second signal pressure output valve SC2 flows into the holding pressure input port 106 via the oil passage L28 and the oil passage L26. As a result, the second signal pressure Psc2 from the second signal pressure output valve SC2 acts on the pressure-receiving surface of the first spool S1 on the first spring SP1 side, and the first switching valve 100B is in the first state. Furthermore, in the hydraulic control device 60B, the pressure-receiving surface of the first spool S1 on the first signal pressure input port 105 side and the pressure-receiving surface on the holding pressure input port 106 (first spring SP1) side have the same area. Therefore, when the first switching valve 100B forms the first state and the second signal pressure output valve SC2 outputs the second signal pressure Psc2, even if the first signal pressure Psc1 from the first signal pressure output valve SC1 is supplied to the first signal pressure input port 105, the first switching valve 100B continues to form the first state.

[0076] On the other hand, when the second signal pressure Psc2 from the second signal pressure output valve SC2 is not supplied to the holding pressure input port 106 and the first signal pressure Psc1 from the first signal pressure output valve SC1 is supplied to the first signal pressure input port 105, the first spool S1 moves downward in FIG. 12 against the biasing force of the first spring SP1 due to a thrust acting on the first spool S1 by the first signal pressure Psc1, and the first switching valve 100B is in the second state (the state of the right half in FIG. 12). In the second state of the first switching valve 100B, the first spool S1 blocks communication between the main pressure input port 101 and the main pressure output port 102 and also blocks communication between the inlet port 111 and the outlet port 112. Furthermore, in the second state, the first spool S1 connects the inlet port 111 to the parking port 117.

[0077] The second switching valve 200B is a spool valve including a second spool S2 that has a plurality of lands and is arranged axially movably within the valve body 600B, and a second spring SP2 that urges the second spool S2 upward in Fig. 12. Furthermore, the second switching valve 200B includes an input port 201', a first output port 203, a second output port 204, a second signal pressure input port 205, a first inflow port 211, a second inflow port 212, and a signal pressure outlet port 215.

[0078] The input port 201' of the second switching valve 200B communicates with the output port of the linear solenoid valve SL2 via an oil passage L31 formed in the valve body 600B. The first output port 203 communicates with an oil passage L33 formed in the valve body 600B, and the second output port 204 communicates with an oil passage L34 formed in the valve body 600B. The second signal pressure input port 205 is located on the opposite side of the spring chamber in which the second spring SP2 is disposed, and communicates with the outflow port 112 of the first switching valve 100B via oil passages L30 and L28 formed in the valve body 600B. The first inflow port 211 communicates with the outflow port 112 of the first switching valve 100B via an oil passage L28 formed in the valve body 600B. Furthermore, the second inflow port 212 communicates with output ports of linear solenoid valves SL3, SL4, and SL5, which serve as dedicated pressure regulating valves, via oil passage L32 formed in the valve body 600B, etc. The signal pressure outflow port 215 communicates with oil passage L35 formed in the valve body 600B.

[0079] In the hydraulic control device 60B, the installation state of the second switching valve 200B is a first communication state (the state of the left half in FIG. 12 ) in which the second spool S2 is urged upward in FIG. 12 by the second spring SP2 without hydraulic oil (second signal pressure Psc2) being supplied to the second signal pressure input port 205 from the second signal pressure output valve SC2 via the inlet port 111, the outlet port 112, and the oil passages L28 and L30 of the first switching valve 100B. In the first communication state (installed state) of the second switching valve 200B, the second spool S2 communicates between the input port 201′ and the second output port 204, and also communicates between the second inlet port 212 and the signal pressure outlet port 215. Furthermore, in the first communication state, the second spool S2 blocks communication between the input port 201' and the first output port 203 and between the first inflow port 211 and the signal pressure outflow port 215.

[0080] On the other hand, when hydraulic oil, i.e., the second signal pressure Psc2, is supplied to the second signal pressure input port 205 from the second signal pressure output valve SC2, the second spool S2 moves downward in FIG. 12 against the biasing force of the second spring SP2 due to a thrust acting on the second spool S2 by the second signal pressure Psc2, and the second changeover valve 200B is in the second communication state (the state of the right half in FIG. 12). In the second communication state of the second changeover valve 200B, the second spool S2 communicates between the input port 201′ and the first output port 203 and between the first inflow port 211 and the signal pressure outlet port 215. Furthermore, in the second communication state, the second spool S2 blocks communication between the input port 201′ and the second output port 204 and between the second inflow port 212 and the signal pressure outlet port 215.

[0081] The third switching valve 300B is a spool valve including a third spool S3 that has a plurality of lands and is arranged axially movably within the valve body 600B, and a third spring SP3 that urges the third spool S3 upward in Fig. 12. The third switching valve 300B further includes a first input port 311, a second input port 312, a first supply port 313, a second supply port 314, a third signal pressure input port 315, a switch port 316, a holding pressure inlet port 317, a holding pressure outlet port 318, and a holding pressure introduction port 319.

[0082] The first input port 311 of the third switching valve 300B communicates with the first output port 203 of the second switching valve 200B via an oil passage L33 formed in the valve body 600B, and the second input port 312 communicates with the second output port 204 of the second switching valve 200B via an oil passage L34 formed in the valve body 600B. The first supply port 313 communicates with the engagement oil chamber of the clutch C2 via an oil passage formed in the valve body 600B, and the second supply port 314 communicates with the engagement oil chamber of the brake B2 via an oil passage formed in the valve body 600B. The third signal pressure input port 315 is located on the opposite side of the spring chamber in which the third spring SP3 is disposed, and communicates with the signal pressure outlet port 215 of the second switching valve 200B via the oil passage L35 of the valve body 600B. The switching port 316 is also connected to a spring chamber in which the first spring SP1 is disposed, and is also connected to an output port of the third signal pressure output valve SC3 via an oil passage formed in the valve body 600. The holding pressure inlet port 317 is supplied with a substantially constant modulator pressure Pmod generated by the modulator valve. The holding pressure outlet port 318 is also connected to an oil passage L36 formed in the valve body 600B. The holding pressure introduction port 319 faces a holding pressure receiving surface S3p formed in the third spool S3, and is also connected to the holding pressure outlet port 318 via the oil passage L36. The holding pressure inlet port 317 may be supplied with line pressure PL instead of the modulator pressure Pmod.

[0083] In the hydraulic control device 60B, the installation state of the third switching valve 300B is a first supply state (the state of the left half in FIG. 12) in which the third spool S3 is urged upward in FIG. 12 by the third spring SP3 without hydraulic oil (second signal pressure Psc2) from the second signal pressure output valve SC2 or hydraulic oil (hydraulic pressure) from any one of the linear solenoid valves SL3, SL4, and SL5 being supplied to the third signal pressure input port 315 via the second switching valve 200B and the oil passage L35. In the first supply state (installed state) of the third switching valve 300B, the third spool S3 blocks communication between the first input port 311 and the first supply port 313 and establishes communication between the second input port 312 and the second supply port 314.

[0084] On the other hand, when hydraulic oil (second signal pressure Psc2) from second signal pressure output valve SC2 or hydraulic oil (hydraulic pressure) from any one of linear solenoid valves SL3, SL4, and SL5 is supplied to third signal pressure input port 315 via second selector valve 200B and oil passage L35, the third spool S3 moves downward in FIG. 12 against the biasing force of third spring SP3 due to a thrust acting on the third spool S3 due to the second signal pressure Psc2, and third selector valve 300B establishes the second supply state (the state of the right half in FIG. 12). In the second supply state of third selector valve 300B, third spool S3 connects first input port 311 and first supply port 313 and blocks communication between second input port 312 and second supply port 314.

[0085] In addition, in the hydraulic control device 60B, when the third switching valve 300B establishes the second supply state, the hydraulic oil supplied from the modulator valve to the holding pressure inlet port 317, i.e., the modulator pressure Pmod, is supplied to the holding pressure introduction port 319 via the holding pressure outlet port 318 and acts on the holding pressure pressure receiving surface S3p of the third spool S3. Furthermore, the pressure receiving area of ​​the holding pressure pressure receiving surface S3p is determined so that the thrust generated by the modulator pressure Pmod acting on the holding pressure pressure receiving surface S3p balances with the biasing force generated by the third spring SP3 in the second supply state. As a result, once the third switching valve 300B establishes the second supply state by supplying hydraulic oil (hydraulic pressure) to the third signal pressure input port 315, the third switching valve 300B continues to establish (maintain) the second supply state even if the supply of hydraulic oil (hydraulic pressure) to the third signal pressure input port 315 is cut off. In contrast, when the third signal pressure is supplied from the third signal pressure output valve SC3 to the switching port 316 (spring chamber), the third switching valve 300B forms the first supply state regardless of whether or not hydraulic oil (hydraulic pressure) is supplied to the third signal pressure input port 315.

[0086] Next, the operation of the hydraulic control device 60B will be described with reference to FIGS.

[0087] When the ignition switch (start switch) of the vehicle 10 is turned on with the shift lever 95 set to the parking position, the TMECU 21 supplies current to the electromagnetic parts of the first and second signal pressure output valves SC1, SC2 so that the first and second signal pressures Psc1, Psc2 are output, as shown in Fig. 13. This causes the first switching valve 100B to establish the second state, as shown in Fig. 14, whereby communication between the source pressure input port 101 and the source pressure output port 102 and communication between the inflow port 111 and the outflow port 112 are blocked, and communication between the inflow port 111 and the parking port 117 is established. Therefore, when the shift lever 95 is set to the parking position, as shown in Fig. 14, the second signal pressure Psc2 from the second signal pressure output valve SC2 is supplied to the parking lock mechanism 70 via the first switching valve 100 (the inflow port 111 and the parking port 117), thereby establishing the parking lock state.

[0088] Furthermore, by blocking communication between the inlet port 111 and outlet port 112 of the first switching valve 100B, the second signal pressure Psc2 from the second signal pressure output valve SC2 is not supplied to the second signal pressure input port 205 (and the first inlet port 211) of the second switching valve 200B, and the second switching valve 200B establishes the first communication state. As a result, the input port 201′ is communicated with the second output port 204, and the second inlet port 212 is communicated with the signal pressure outlet port 215. Furthermore, by blocking communication between the first inlet port 211 and signal pressure outlet port 215 of the second switching valve 200B, the second signal pressure Psc2 from the second signal pressure output valve SC2 is not supplied to the third signal pressure input port 315 of the third switching valve 300B, and even if the modulator pressure Pmod is supplied to the holding pressure inlet port 317, the third switching valve 300B establishes the first supply state. As a result, the second input port 312 and the second supply port 314 are connected to each other, and the first input port 311 and the first supply port 313 are disconnected from each other. Furthermore, when the shift lever 95 is set to the neutral position, the TMECU 21 supplies current to the electromagnetic part of the first signal pressure output valve SC1 so that the first signal pressure Psc1 is output, and de-energizes the second and third signal pressure output valves SC2, SC3, as shown in Fig. 13. This stops the supply of the second signal pressure Psc2 from the second signal pressure output valve SC2 to the parking lock mechanism 70, thereby enabling the parking lock state to be released.

[0089] On the other hand, when the driver sets the shift lever 95 to the reverse position, the TMECU 21 supplies current to the electromagnetic parts of the first and third signal pressure output valves SC1, SC3 so that the first and third signal pressures Psc1, Psc3 are output, as shown in FIG. 13. Furthermore, the TMECU 21 controls the linear solenoid valves SL2 and SL3 according to a predetermined procedure. As a result, as shown in FIG. 15, the first switching valve 100B establishes the second state, and the second switching valve 200B establishes the first communication state. Furthermore, by supplying the third signal pressure from the third signal pressure output valve SC3 to the switching port 316 (spring chamber), the third switching valve 300B establishes the first supply state, regardless of whether or not hydraulic oil (hydraulic pressure) is supplied to the third signal pressure input port 315. Then, hydraulic oil (line pressure PL) from the primary regulator valve side is supplied to the input port of linear solenoid valve SL3 via oil passages L21 and L24, and hydraulic oil whose pressure is adjusted by linear solenoid valve SL3 is supplied to the engagement oil chamber of clutch C3. Also, hydraulic oil (line pressure PL) from the primary regulator valve side is supplied to the input port of linear solenoid valve SL2 via oil passage L23, and hydraulic oil whose pressure is adjusted by linear solenoid valve SL2 (hydraulic pressure Psl2) is supplied to the engagement oil chamber of brake B2 via input port 201′ and second output port 204 of second selector valve 200B and second input port 312 and second supply port 314 of third selector valve 300B.

[0090] As a result, the clutch C3 and the brake B2 can be engaged to establish first reverse gear. When the shift lever 95 is set to the reverse position, the TMECU 21 starts controlling the linear solenoid valves SL2 and SL3 after the third signal pressure Psc3 is supplied from the third signal pressure output valve SC3 to the switching port 316 of the third changeover valve 300B. This makes it possible to maintain the third changeover valve 300B in the first supply state even when hydraulic oil (hydraulic pressure) from the linear solenoid valve SL3 is supplied to the third signal pressure input port 315 via the second inlet port 212 and the signal pressure outlet port 215 of the second changeover valve 200B.

[0091] Furthermore, when the driver sets the shift lever 95 to the drive position or sport position (forward driving position), the TMECU 21 de-energizes the electromagnetic parts of the first, second and third signal pressure output valves SC1, SC2 and SC3 to stop the output of all of the first, second and third signal pressures Psc1, Psc2 and Psc3, as shown in Fig. 13. This causes the first switching valve 100B to establish the first state, as shown in Fig. 16, whereby the main pressure input port 101 and the main pressure output port 102 communicate with each other and the inlet port 111 and the outlet port 112 communicate with each other. Furthermore, since the second signal pressure Psc2 is not output from the second signal pressure output valve SC2, even if the inlet port 111 and outlet port 112 of the first selector valve 100B are in communication with each other, the second selector valve 200B establishes the first supply state, and the input port 201′ and the second output port 204 are in communication with each other, and the second inlet port 212 and the signal pressure outlet port 215 are in communication with each other. Furthermore, even if the second inlet port 212 and the signal pressure outlet port 215 of the second selector valve 200B are in communication with each other, if no hydraulic pressure is output from any of the linear solenoid valves SL3, SL4, and SL5, the third selector valve 300B establishes the first supply state, and the second input port 312 and the second supply port 314 are in communication with each other.

[0092] When the shift lever 95 is set to a forward drive position such as the drive position, hydraulic oil (line pressure PL) from the primary regulator valve is supplied from oil passage L21 of the valve body 600B through a source pressure input port 101 and a source pressure output port 102 of the first selector valve 100B, oil passage L22, etc. to input ports of linear solenoid valves SL1, SL4, and SL5 corresponding to the clutches C1, C4 and brake B1, which are engaged only when the forward gear is established. The input port of linear solenoid valve SL2 is also in communication with oil passage L1 through oil passage L23. Therefore, by controlling the linear solenoid valves SL1 and SL2 by the TMECU 21, hydraulic oil whose pressure is adjusted by the linear solenoid valve SL1 is supplied to the engagement oil chamber of the clutch C1, and hydraulic oil whose pressure is adjusted by the linear solenoid valve SL2 (hydraulic pressure Psl2) is supplied to the engagement oil chamber of the brake B2 via the oil passage L31, the input port 201′ and the second output port 204 of the second changeover valve 200B, the oil passage L34, the second input port 312 and the second supply port 314 of the third changeover valve 300B. This makes it possible to engage the clutch C1 and the brake B2 and establish the first forward speed.

[0093] Furthermore, when an upshift condition for upshifting the gear to second forward speed or the like is satisfied while first forward speed is established, the TMECU 21 supplies current to the electromagnetic parts of the second signal pressure output valve SC2 while de-energizing the electromagnetic parts of the first and third signal pressure output valves SC1, SC3, as shown in Fig. 13. As a result, as shown in Fig. 17, the first changeover valve 100B establishes the first state, and the source pressure input port 101 and the source pressure output port 102 communicate with each other, and the inlet port 111 and the outlet port 112 communicate with each other. Furthermore, the second signal pressure Psc2 from the second signal pressure output valve SC2 is supplied to the second signal pressure input port 205 via the inlet port 111, the outlet port 112, and the oil passage L28 of the first changeover valve 100B, and the second changeover valve 200B establishes the second communication state. As a result, the input port 201′ and the first output port 203 are communicated with each other, and the first inflow port 211 and the signal pressure outflow port 215 are communicated with each other. Furthermore, when the second switching valve 200B establishes the second communication state, the first inflow port 211 and the signal pressure outflow port 215 are communicated with each other, allowing the outflow of hydraulic oil (second signal pressure Psc2) supplied from the second signal pressure output valve SC2 to the first inflow port 211 via the oil passage L28, separately from the second signal pressure input port 205. The hydraulic oil from the second signal pressure output valve SC2 supplied to the first inflow port 211 is then supplied to the third signal pressure input port 315 of the third switching valve 300B via the signal pressure outflow port 215 of the second switching valve 200B and the oil passage L35. As a result, the third switching valve 300B establishes the second supply state, and the first input port 311 and the first supply port 313 are communicated with each other.

[0094] Additionally, hydraulic oil (line pressure PL) from the primary regulator valve side is supplied from oil passage L21 of valve body 600B via source pressure input port 101 and source pressure output port 102 of first selector valve 100B, oil passage L22, etc. to input ports of linear solenoid valves SL1, SL4, and SL5 corresponding to clutches C1 and C4 and brake B1, which are engaged only when forward gears are established. Furthermore, the input port of linear solenoid valve SL2 communicates with oil passage L1 via oil passage L23, and the input port of linear solenoid valve SL3 communicates with oil passage L1 via oil passage L24. Therefore, depending on the vehicle speed and accelerator pedal position of vehicle 10, hydraulic pressure from two of linear solenoid valves SL1-SL5 can be used to engage any two of clutches C1-C4 and brake B1 to establish a desired gear from second forward gear to eighth forward gear.

[0095] Here, if an abnormality such as sticking of the second spool S2 occurs in the second switching valve 200B of the hydraulic control device 60B, even though the second signal pressure Psc2 from the second signal pressure output valve SC2 is supplied to the second signal pressure input port 205, as shown in Figure 18, the second switching valve 200B may form a first communication state that allows the supply of hydraulic pressure Psl2 from the linear solenoid valve SL2 to the brake B2 (second hydraulic engagement element) side. Furthermore, the fifth forward speed to the eighth forward speed of the automatic transmission 25 are formed by engaging the clutch C2 (first engagement element) with any one of the clutches C1, C3, C4 and the brake B1, but if the second switching valve 200B, which should normally form the second communication state, forms the first communication state when any of the fifth forward speed to the eighth forward speed should be formed, and the hydraulic pressure Psl2 from the linear solenoid valve SL2 is supplied to the brake B2, a gear other than the fifth forward speed to the eighth forward speed will be formed.

[0096] That is, when the fifth forward gear is established, if the second selector valve 200B establishes the first communication state and hydraulic pressure Psl2 from the linear solenoid valve SL2 is supplied to the brake B2, there is a risk that the first forward gear will be established and the vehicle 10 will suddenly decelerate, as can be seen from Fig. 3. Also, when the sixth forward gear is established, if the second selector valve 200B establishes the first communication state and hydraulic pressure Psl2 from the linear solenoid valve SL2 is supplied to the brake B2, there is a risk that the second reverse gear will be established, as can be seen from Fig. 3. Furthermore, when the seventh forward gear is established, if the second selector valve 200B establishes the first communication state and hydraulic pressure Psl2 from the linear solenoid valve SL2 is supplied to the brake B2, there is a risk that the first reverse gear will be established, as can be seen from Fig. 3.

[0097] In consideration of these, the second switching valve 200B of the hydraulic control device 60B is configured to, when the first communication state is established, communicate the second inflow port 212 with the signal pressure outflow port 215 and supply hydraulic oil (hydraulic pressure) from any of the linear solenoid valves SL3, SL4, and SL5 serving as dedicated pressure regulating valves to the third signal pressure input port 315 of the third switching valve 300B. Furthermore, once the second supply state is established by supplying hydraulic oil (hydraulic pressure) to the third signal pressure input port 315, the third switching valve 300B of the hydraulic control device 60B continues to establish (maintain) the second supply state even if the supply of hydraulic oil (hydraulic pressure) to the third signal pressure input port 315 is cut off. As a result, even if the second selector valve 200B should stick with the first supply state in place, hydraulic oil (hydraulic pressure) can be supplied from any one of the linear solenoid valves SL3, SL4, and SL5 to the third signal pressure input port 315 of the third selector valve 300B in accordance with the establishment of any one of the second, third, fourth, sixth, seventh, and eighth forward speeds, and the third selector valve 300B can be maintained in the second supply state in which communication between the second input port 312 and the second supply port 314 is blocked. As a result, even if the second selector valve 200B should stick with the first supply state in place, hydraulic pressure Psl2 from the linear solenoid valve SL2 is not supplied to the brake B2 when any one of the fifth to eighth forward speeds should be established, so that the automatic transmission 25 can be placed in the neutral state. Therefore, the hydraulic control device 60B can effectively suppress sudden deceleration of the vehicle 10 due to a downshift from the fifth forward speed to the first forward speed.

[0098] On the other hand, if an abnormality occurs that prevents the second signal pressure Psc2 from being output from the second signal pressure output valve SC2 when any of the forward fifth, fifth, eighth, and eighth gears should be established, the second changeover valve 200B establishes the first communication state, which connects the input port 201′ and the second output port 204, due to the biasing force of the second spring SP2, as shown in FIG. 19 . In this case, too, the third changeover valve 300B can be maintained in the second supply state, which blocks communication between the second input port 312 and the second supply port 314, depending on whether any of the forward second, third, fourth, sixth, seventh, and eighth gears is established. This prevents the hydraulic pressure Psl2 from being supplied to the brake B2 from the linear solenoid valve SL2, thereby placing the automatic transmission 25 in neutral. Therefore, in this case too, sudden deceleration of the vehicle 10 due to a downshift from forward fifth to forward first gear can be effectively suppressed.

[0099] As described above, in the hydraulic control device 60B of the present disclosure, the hydraulic pressure Psl2 generated (adjusted) by the linear solenoid valve SL2 (dual-purpose pressure regulating valve) can be supplied to the clutch C2 (first hydraulic engagement element) and the brake B2 (second hydraulic engagement element) that is engaged when at least the first reverse gear and the second reverse gear of the automatic transmission 25 are established but is not simultaneously engaged with the clutch C2. This makes it possible to reduce the number of linear solenoid valves (pressure regulating valves) in the hydraulic control device 60B, thereby reducing costs by reducing the number of linear solenoid valves and improving efficiency by reducing oil leakage.

[0100] Furthermore, in the hydraulic control device 60B, when the fifth forward speed and the eighth forward speed are established, if the second changeover valve 200B sticks in a state (first communication state) that allows the supply of hydraulic pressure Psl2 from the linear solenoid valve SL2 serving as a dual-purpose pressure regulating valve to the brake B2 side, hydraulic oil (hydraulic pressure) from any of the linear solenoid valves SL3, SL4, and SL5 serving as dedicated pressure regulating valves is supplied to the third signal pressure input port 315 of the third changeover valve 300B via the second changeover valve 200B. Furthermore, if the second signal pressure Psc2 is no longer output from the second signal pressure output valve SC2 due to the occurrence of some kind of abnormality, hydraulic oil (hydraulic pressure) from any of the linear solenoid valves SL3, SL4, and SL5 is supplied to the third signal pressure input port 315 of the third changeover valve 300B via the second changeover valve 200B that is no longer supplied with the second signal pressure Psc2 and is now in the first communication state.

[0101] As a result, even if an abnormality occurs in the second switching valve 200B or the second signal pressure output valve SC2, hydraulic oil (hydraulic pressure) can be supplied from one of the linear solenoid valves SL3, SL4, and SL5 to the third signal pressure input port 315 of the third switching valve 300B depending on the formation of any of the forward second, third, fourth, sixth, seventh, and eighth speeds, and the third switching valve 300B can be maintained in the second supply state in which communication between the second input port 312 and the second supply port 314 is blocked. Therefore, even if an abnormality in the second switching valve 200B or the second signal pressure output valve SC2 causes the second switching valve 200B to form a first supply state in which the second switching valve 200B restricts the supply of hydraulic pressure Psl2 from the linear solenoid valve SL2 to the clutch C2 and allows the supply of hydraulic pressure Psl2 to the brake B2, the third switching valve 300B can restrict the supply of hydraulic pressure Psl2 from the linear solenoid valve SL2 from the second switching valve 200B to the brake B2, thereby placing the automatic transmission 25 in a neutral state.

[0102] As a result, the hydraulic control device 60B can selectively supply hydraulic pressure Psl2 to the clutch C2 and the brake B2 from one linear solenoid valve SL2, thereby reducing costs and improving efficiency while ensuring a fail-safe. However, the hydraulic control device 60B may also be applied to a transmission that provides multiple gears by selectively engaging three or more hydraulic engagement elements.

[0103] In the automatic transmission 25, the clutch C2 is engaged when multiple low forward gears including the start gear are established, i.e., when forward fifth gear through forward eighth gear, which are higher than forward first gear through forward fourth gear, are established, and the brake B2 is engaged when reverse first gear and reverse second gear are established and when forward first gear, which is the start gear, is established. Furthermore, in the automatic transmission 25, when forward second gear, third gear, and fourth gear among the multiple low forward gears, and forward sixth gear, seventh gear, and eighth gear among the multiple high forward gears, one of the linear solenoid valves SL3, SL4, and SL5, which serve as dedicated pressure regulating valves, generates hydraulic pressure to the corresponding clutches C3, C4 or brake B1. By applying the hydraulic control device 60B to such an automatic transmission 25, it is possible to selectively supply hydraulic pressure Psl2 from one linear solenoid valve SL2 to the clutch C2 and the brake B2 that is not simultaneously engaged with the clutch C2, and to ensure good fail-safe when the high speed gears of the automatic transmission 25, i.e., forward 5th gear to forward 8th gear, are formed.

[0104] Furthermore, in the first switching valve 100B, when the first signal pressure Psc1 is not supplied to the first signal pressure input port 105, and when the first signal pressure Psc1 is supplied to the first signal pressure input port 105 and the second signal pressure Psc2 is supplied to the holding pressure input port 106 via the inlet port 111 and the outlet port 112, the first spool S1 establishes a first state in which the biasing force of the first spring SP1 connects the inlet port 111 and the outlet port 112. On the other hand, when the first signal pressure Psc1 is supplied to the first signal pressure input port 105, the first spool S1 establishes a second state in which the first spool S1 blocks communication between the inlet port 111 and the outlet port 112 against the biasing force of the first spring SP1. Furthermore, in the second switching valve 200B, when the second signal pressure Psc2 is not supplied to the second signal pressure input port 205, the second spool S2 establishes a first communication state in which the input port 201′ and the second output port 204 are communicated with each other and the second inflow port 212 and the signal pressure outlet port 215 are communicated with each other by the biasing force of the second spring SP2. On the other hand, when the second signal pressure Psc2 is supplied to the second signal pressure input port 205, the second spool S2 establishes a second communication state in which the input port 201′ and the first output port 200 are communicated with each other and the first inflow port 211 and the signal pressure outlet port 215 are communicated with each other against the biasing force of the second spring SP2. Furthermore, in the third switching valve 300B, when hydraulic oil (hydraulic pressure) is not supplied to the third signal pressure input port 315 from the signal pressure outlet port 215 of the second switching valve 200B from the second signal pressure output valve SC2 or any of the linear solenoid valves SL3, SL4, and SL5 serving as dedicated pressure regulating valves, and when hydraulic oil (hydraulic pressure) is supplied to the third signal pressure input port 315 from any of the linear solenoid valves SL3, SL4, and SL5 from the signal pressure outlet port 215 of the second switching valve 200B and the third signal pressure Psc3 is supplied to the switching port 316 from the third signal pressure output valve SC3, the third spool S3 forms a first supply state in which the second input port 312 and the second supply port 314 communicate with each other.Furthermore, when hydraulic oil (hydraulic pressure) is supplied to third signal pressure input port 315 from either second signal pressure output valve SC2 or linear solenoid valves SL3, SL4, and SL5 through signal pressure outlet port 215 of second selector valve 200B, third spool S3 establishes a second supply state in which first input port 311 communicates with first supply port 313. Additionally, in third selector valve 300B, when hydraulic oil (hydraulic pressure) is not supplied to third signal pressure input port 315 from either second signal pressure output valve SC2 or linear solenoid valves SL3, SL4, and SL5 through signal pressure outlet port 215 of second selector valve 200B, third spool S3 blocks communication between holding pressure inlet port 317 and holding pressure outlet port 318 due to the biasing force of third spring SP3. Furthermore, when hydraulic oil (hydraulic pressure) is supplied from the second signal pressure output valve SC2 or the linear solenoid valves SL3, SL4, and SL5 through the signal pressure outlet port 215 of the second selector valve 200B to the third signal pressure input port 315, the third spool S3 communicates the holding pressure inlet port 317 with the holding pressure outlet port 318 against the biasing force of the third spring SP3, and applies the modulator pressure Pmod as the holding pressure based on the line pressure PL as the source pressure to the holding pressure pressure-receiving surface S3p of the third spool S3 through the holding pressure introduction port 319. This makes it possible to place the automatic transmission 25 in the neutral state and ensure a good fail-safe when an abnormality occurs in the second selector valve 200B or the second signal pressure output valve SC2.

[0105] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present disclosure. Furthermore, the above-described embodiment is merely a specific form of the invention described in the Summary of the Invention, and does not limit the elements of the invention described in the Summary of the Invention. [Industrial Applicability]

[0106] The invention of the present disclosure can be used in the hydraulic control device manufacturing industry and the like. [Explanation of symbols]

[0107] 10 Vehicle, 12 Engine, 20 Power transmission device, 21 Transmission electronic control unit (TMECU), 24 Mechanical oil pump, 25 Automatic transmission, 60, 60B Hydraulic control device, 600, 600B Valve body, 100, 100B First switching valve, 101 Main pressure input port, 102 Main pressure output port, 103 First main pressure output port, 104 Second main pressure output port, 105 First signal pressure input port, 106 Holding pressure input port, 107 First inflow port, 108 First outflow port, 109 Second inflow port, 110 Second outflow port, 111 Inflow port, 112 Outflow port, 117 Parking port, 200, 200B Second switching valve, 201 First input port, 201′ Input port, 202 Second input port, 203 First output port, 204 Second output port, 205 Second signal pressure input port, 209 Inlet port, 210 Outlet port, 211 First inlet port, 212 Second inlet port, 215 Signal pressure outlet port, 300, 300B Third switching valve, 301 Third input port, 303 Third output port, 305, 315 Third signal pressure input port, 306 Holding pressure input port, 311 First input port, 312 Second input port, 313 First supply port, 314 Second supply port, 316 Switching port, 317 Holding pressure inlet port, 318 Holding pressure outlet port, 319 Holding pressure introduction port, B1, B2 Brake, C1, C2, C3, C4 Clutch, S1 First spool, S2 Second spool, S3 Third spool, SC1 First signal pressure output valve, SC2 Second signal pressure output valve, SC3 3rd signal pressure output valve, SL1, SL2, SL3, SL4, SL5 linear solenoid valve, SP1 1st spring, SP2 2nd spring, SP3 3rd spring.

Claims

1. A hydraulic control device for a transmission that forms a plurality of forward gears and the reverse gear by selectively engaging at least any two of a first hydraulic engagement element, a second hydraulic engagement element that is engaged when at least a reverse gear is formed and that is not simultaneously engaged with the first hydraulic engagement element, and remaining hydraulic engagement elements, a plurality of pressure regulating valves including a dual-purpose pressure regulating valve that regulates a source pressure to generate hydraulic pressure to the first hydraulic engagement element and the second hydraulic engagement element, and at least one dedicated pressure regulating valve that regulates the source pressure to generate hydraulic pressure to the corresponding remaining hydraulic engagement element; a first signal pressure output valve that outputs a first signal pressure; a second signal pressure output valve that outputs a second signal pressure; a first switching valve that operates by receiving the first signal pressure from the first signal pressure output valve and the second signal pressure from the second signal pressure output valve, and that allows at least oil supplied from the second signal pressure output valve to flow out when the first signal pressure is not being supplied and when both the first and second signal pressures are being supplied; a second switching valve that, when the second signal pressure is not supplied from the second signal pressure output valve, allows the hydraulic pressure to be supplied from the dual-purpose pressure regulating valve to the second hydraulic engagement element side and restricts the hydraulic pressure to be supplied from the dual-purpose pressure regulating valve to the first hydraulic engagement element side, and that, when the second signal pressure is supplied from the second signal pressure output valve, allows the hydraulic pressure to be supplied from the dual-purpose pressure regulating valve to the first hydraulic engagement element side and restricts the hydraulic pressure to be supplied from the dual-purpose pressure regulating valve to the second hydraulic engagement element side; a third changeover valve that allows the hydraulic pressure to be supplied from the dual-purpose pressure regulating valve to the second hydraulic engagement element from the second changeover valve when the second signal pressure is not supplied from the second signal pressure output valve, and that restricts the hydraulic pressure to be supplied from the dual-purpose pressure regulating valve to the second hydraulic engagement element from the second changeover valve when the second signal pressure is supplied from the second signal pressure output valve; A hydraulic control device comprising:

2. The hydraulic control device according to claim 1, the first switching valve, when not receiving the first signal pressure and when receiving both the first and second signal pressures, at least allows the supply of the source pressure to the dual-purpose pressure regulating valve and the outflow of oil supplied from the second signal pressure output valve, and, when receiving the first signal pressure, allows the supply of the source pressure to the second hydraulic engagement element and restricts the outflow of oil supplied from the second signal pressure output valve; the second switching valve allows the hydraulic pressure to be supplied from the dual-purpose pressure regulating valve to the second hydraulic engagement element when the second signal pressure is not supplied from the second signal pressure output valve, and allows the original pressure to be supplied from the first switching valve to the second hydraulic engagement element when the second signal pressure is supplied from the second signal pressure output valve; the third switching valve allows the oil pressure or the original pressure to be supplied from the dual-purpose pressure regulating valve to the second hydraulic engagement element when the second signal pressure is not supplied from the second signal pressure output valve via the first switching valve, and regulates the supply of the oil pressure or the original pressure from the dual-purpose pressure regulating valve to the second hydraulic engagement element when the second signal pressure is supplied from the second signal pressure output valve via the first switching valve.

3. The hydraulic control device according to claim 2, the first hydraulic engagement element is engaged when a plurality of forward high speed stages are formed that are higher than a plurality of forward low speed stages including the start stage of the transmission, The second hydraulic engagement element is engaged when the reverse gear is established and when the start gear is established. Hydraulic control device.

4. The hydraulic control device according to claim 2 or 3, the first switching valve has a first spool, a first spring that biases the first spool, a source pressure input port to which the source pressure is supplied, a first source pressure output port that communicates with an input port of the dual-purpose pressure regulating valve, a second source pressure output port, a first signal pressure input port to which the first signal pressure from the first signal pressure output valve is supplied, an inlet port to which the second signal pressure is supplied, an outlet port, and a holding pressure input port that communicates with the outlet port, and when the first signal pressure is not supplied to the first signal pressure input port and when the first signal pressure is supplied to the first signal pressure input port and when the second signal pressure is supplied to the holding pressure input port via the inflow port and the outflow port, the first spool establishes a first state in which the main pressure input port communicates with the first main pressure output port and also communicates with the inflow port and the outflow port due to the biasing force of the first spring, and when the first signal pressure is supplied to the first signal pressure input port, the first spool establishes a second state in which the main pressure input port communicates with the second main pressure output port against the biasing force of the first spring and also interrupts communication between the inflow port and the outflow port, the second switching valve has a second spool, a second spring biasing the second spool, a first input port to which the hydraulic pressure from the combined pressure regulating valve is supplied, a second input port communicating with the second source pressure output port of the first switching valve, a first output port communicating with an oil chamber of the first hydraulic engagement element, a second output port, and a second signal pressure input port to which the second signal pressure from the second signal pressure output valve is supplied, and when the second signal pressure is not supplied to the second signal pressure input port, the second spool establishes a first supply state in which the first input port and the second output port are communicated with each other by the biasing force of the second spring and the second input port and the second output port are blocked from communication with each other, and when the second signal pressure is supplied to the second signal pressure input port, the second spool establishes a second supply state in which the first input port and the first output port are communicated with each other and the second input port and the second output port are communicated with each other against the biasing force of the second spring, the third changeover valve has a third spool, a third spring that biases the third spool, a third input port that communicates with the second output port of the second changeover valve, a third output port that communicates with an oil chamber of the second hydraulic engagement element, and a third signal pressure input port that communicates with the outflow port of the first changeover valve, and when the second signal pressure is not supplied to the third signal pressure input port from the outflow port of the first changeover valve, the third spool forms a supply state in which the third input port and the third output port communicate with each other by the biasing force of the third spring, and when the second signal pressure is supplied to the third signal pressure input port from the outflow port of the first changeover valve, the third spool forms a block state in which the communication between the third input port and the third output port is blocked against the biasing force of the third spring.

5. The hydraulic control device according to claim 1, the second switching valve, when not receiving the second signal pressure from the second signal pressure output valve via the first switching valve, allows outflow of oil supplied from at least one of the dedicated pressure regulating valves that generates oil pressure to the hydraulic engagement element that is not engaged simultaneously with the second hydraulic engagement element when the plurality of forward speeds are formed, and allows outflow of oil separately supplied from the second signal pressure output valve when receiving the second signal pressure from the second signal pressure output valve via the first switching valve; When the oil is not supplied from the second signal pressure output valve or the dedicated pressure regulating valve via the second switching valve, the third switching valve forms a first supply state in which the oil is restricted from being supplied from the dual-purpose pressure regulating valve to the first hydraulic engagement element from the second switching valve and the oil is permitted to be supplied from the dual-purpose pressure regulating valve to the second hydraulic engagement element from the second switching valve, and a hydraulic control device that receives a supply of the oil from the signal pressure output valve or the oil from the dedicated pressure regulating valve, forms a second supply state that allows the oil pressure to be supplied from the dual-purpose pressure regulating valve to the first hydraulic engagement element from the second changeover valve, and restricts the supply of the oil from the dual-purpose pressure regulating valve from the second changeover valve to the second hydraulic engagement element, and is capable of maintaining the second supply state even when the outflow of the oil from the second signal pressure output valve or the oil from the dedicated pressure regulating valve is restricted by the second changeover valve.

6. The hydraulic control device according to claim 5, the first hydraulic engagement element is engaged when a plurality of forward high speed stages are formed that are higher than a plurality of forward low speed stages including the start stage of the transmission, the second hydraulic engagement element is engaged when the reverse gear is established and when the start gear is established, At least one of the dedicated pressure regulating valves generates hydraulic pressure to the hydraulic engagement element corresponding to when at least one of the plurality of low forward speed stages is established and when at least one of the plurality of high forward speed stages is established.

7. The hydraulic control device according to claim 5 or 6, a third signal pressure output valve that outputs a third signal pressure; the first switching valve has a first spool, a first spring biasing the first spool, a first signal pressure input port to which the first signal pressure from the first signal pressure output valve is supplied, an inlet port to which the second signal pressure is supplied, an outlet port, and a holding pressure input port communicating with the outlet port, and when the first signal pressure is not supplied to the first signal pressure input port and when the first signal pressure is supplied to the first signal pressure input port and the second signal pressure is supplied to the holding pressure input port via the inlet port and the outlet port, the first spool establishes a first state in which the inlet port and the outlet port are communicated by the biasing force of the first spring, and when the first signal pressure is supplied to the first signal pressure input port, the first spool establishes a second state in which the first spool blocks communication between the inlet port and the outlet port against the biasing force of the first spring, The second switching valve has a second spool, a second spring that biases the second spool, an input port to which the hydraulic pressure from the dual-purpose pressure regulating valve is supplied, a first inflow port that communicates with the outflow port of the first switching valve, a second inflow port to which the oil from at least one of the dedicated pressure regulating valves is supplied, a first output port, a second output port, a signal pressure outflow port, and a second signal pressure input port to which the second signal pressure from the second signal pressure output valve is supplied, when the second signal pressure is not supplied to the second signal pressure input port, the second spool establishes a first communication state in which the input port communicates with the second output port and the second inflow port communicates with the signal pressure outflow port by the biasing force of the second spring, and when the second signal pressure is supplied to the second signal pressure input port, the second spool establishes a second communication state in which the input port communicates with the first output port and the first inflow port communicates with the signal pressure outflow port against the biasing force of the second spring, the third switching valve includes a third spool, a third spring that biases the third spool, a first input port that communicates with the first output port of the second switching valve, a second input port that communicates with the second output port of the second switching valve, a first supply port that communicates with an oil chamber of the first hydraulic engagement element, a second supply port that communicates with an oil chamber of the second hydraulic engagement element, a third signal pressure input port that communicates with the signal pressure outflow port of the second switching valve, and a switching port that communicates with a spring chamber in which the spring is disposed and to which the third signal pressure is supplied, and when the oil from the second signal pressure output valve or the oil from the dedicated pressure regulating valve is not supplied from the signal pressure outflow port of the second switching valve to the third signal pressure input port, and when the oil from the dedicated pressure regulating valve is supplied from the signal pressure outflow port of the second switching valve to the third signal pressure input port and the third signal pressure is supplied to the switching port, the third spool is in a state where it ... and when the oil from the second signal pressure output valve or the oil from the dedicated pressure regulating valve is supplied to the third signal pressure input port through the signal pressure outlet port of the second switching valve, the third spool forms the second supply state in which the first input port and the first supply port are communicated with each other.

8. The hydraulic control device according to claim 7, the third selector valve has a holding pressure inlet port to which the source pressure or a holding pressure which is a hydraulic pressure based on the source pressure is supplied, a holding pressure outlet port, and a holding pressure introduction port which communicates with the holding pressure outlet port and faces a holding pressure pressure receiving surface formed on the third spool, and when the oil from the second signal pressure output valve or the oil from the dedicated pressure regulating valve is not supplied to the third signal pressure input port from the signal pressure outlet port of the second selector valve, the third spool blocks communication between the holding pressure inlet port and the holding pressure outlet port by the biasing force of the third spring, and when the oil from the second signal pressure output valve or the oil from the dedicated pressure regulating valve is supplied to the third signal pressure input port from the signal pressure outlet port of the second selector valve, the third spool connects the holding pressure inlet port and the holding pressure outlet port against the biasing force of the third spring.

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