JPH0611020A - Oil pressure controller for vehicular automatic transmission - Google Patents

Abstract

PURPOSE:To prevent an abrupt down-shift even if a shift lever is shifted from a D-position to an L-position during traveling at a high speed by providing a low inhibit valve. CONSTITUTION:In a vehicle which is traveling at a speed higher than a preset vehicle speed, i.e., higher than a third shift speed in a D-position, a pilot oil chamber 92 of a 2-3 shift valve 90 is cut off from an L range circuit 205 and communicated with a reservoir by a low inhibit valve 170 even when a shift lever 11 is shifted from the D-position to an L-position so that a manual valve 10 is shifted from a D-range to an L-range. Accordingly, pressure oil cannot be supplied to the pilot oil chamber 92 of the 2-3 shift valve 90, which is maintained on a high speed operation mode. Consequently, it is possible to prevent an abrupt down-shift from a speed higher than the third shift speed to a second shift speed so as to accurately prevent an abrupt speed reducing shock and over-run of an engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for a vehicle automatic transmission.

[0002]

2. Description of the Related Art In a conventional hydraulic control system for an automatic transmission for a vehicle, when a shift lever is shifted from a D position to an L position in a vehicle running at a shift speed of 3rd or higher, the manual valve is moved from the D range. The line pressure supply circuit is shifted to the L range and the line pressure supply circuit is connected to the L range circuit by the manual valve, and the low speed operation mode in which the speed can be switched to the 1st speed or the 2nd speed or lower 2nd speed and the 3rd or higher 3rd speed
The hydraulic oil of the line pressure supply circuit is supplied as pilot pressure through the L range circuit to the pilot oil chamber of the 2-3 shift valve having the high speed operation mode capable of switching to the 4th speed or the 4th speed, and the shift valve operates at the high speed operation mode. Is switched to the low speed operation mode.

[0003]

By the way, since the above-described operation is obtained in the conventional apparatus irrespective of the vehicle speed, a vehicle running at a high speed at the third speed or higher in the D position. Shift lever to D
When shifting from the position to the L position, pressure oil is supplied as pilot pressure to the pilot oil chamber of the 2-3 shift valve through the L range circuit, the shift valve is switched from the high speed operation mode to the low speed operation mode, and the third gear As described above, the engine may be downshifted rapidly to the second gear, a sudden deceleration shock may occur, and the engine may overrun. The present invention has been made to solve the above-described problem, and the shift lever is shifted from the D position to the L position during high-speed traveling,
To provide a hydraulic control device for an automatic transmission for a vehicle, in which a 2-3 shift valve is maintained in a high-speed operation mode to prevent a sudden downshift even when a manual valve is shifted from a D range to an L range. Has an aim.

[0004]

In order to achieve the above object, according to the present invention, a hydraulic control device for an automatic transmission for a vehicle is manually operated in association with a shift lever to set a line in each range. Manual valve that selectively connects the pressure supply circuit to each range circuit, low-speed operation mode that can switch to 1st or 2nd gear speed below 2nd speed, and 3rd or 4th gear speed above 3rd speed Operates by a 2-3 shift valve that switches to a low speed operation mode when it receives a pilot pressure in the pilot oil chamber and switches to a high speed operation mode when the pilot pressure is removed, and a solenoid valve compatible with the vehicle speed Is controlled to connect the pilot oil chamber of the 2-3 shift valve and the L range circuit, which is one of the range circuits, at a low speed lower than the set vehicle speed. Also at the time faster than the set speed has been configured to include a low inhibit valve for communicating the reservoir by blocking said pilot oil chamber from the L-range circuit.

[0005]

In the hydraulic control system for an automatic transmission for a vehicle according to the present invention, the shift lever is set to D when the vehicle is traveling at a speed higher than the set vehicle speed in the D position at the third speed or higher. Even if the manual valve is shifted from the position to the L position and the manual valve is shifted from the D range to the L range, the low inhibit valve shuts off the pilot oil chamber of the 2-3 shift valve from the L range circuit to communicate with the reservoir. Therefore, although the line pressure supply circuit is connected to the L range circuit by the manual valve, pressure oil is not supplied to the pilot oil chamber of the 2-3 shift valve, and the 2-3 shift valve is maintained in the high-speed operation mode. There is no sudden downshift from the third speed or higher to the second speed, and it is possible to accurately prevent a sudden deceleration shock and engine overrun.

[0006]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a gear train of a four-speed automatic transmission with a lockup mechanism for an automobile, which gear train includes a torque converter T, planetary gear mechanisms G1, G.
2, G3 and a hydraulic clutch L / U for lock-up and hydraulic clutches Co, C1, C2 for shifting, hydraulic brakes Bo, B1, B2 and one-way clutch Fo,
It is equipped with F1, F2 and the like.

FIG. 2 shows the above-mentioned hydraulic clutches L / U and C.
1 shows a hydraulic control device for controlling the operation / non-operation of o, C1, C2 and hydraulic brakes Bo, B1, B2, etc. according to the shift operation of the shift lever 11 and the output (throttle opening) of the engine and the vehicle speed. This hydraulic control device controls a manual valve 10 that operates in response to a shift operation of a shift lever 11, a throttle valve 20 that operates in response to depression of an accelerator pedal (engine output), and a hydraulic pressure supplied to each pilot oil chamber. Cutback valve 30, primary regulator valve 4 that operates in accordance with
0, secondary regulator valve 50, lockup signal valve 60, lockup control valve 70, 1-2 shift valve 80, 2-3 shift valve 9
0,3-4 shift valve 100, reverse control valve 110, accumulator control valve 12
0, modulator valve 130, low coast modulator valve 140, CO exhaust valve 150, orifice control valve 160, low inhibit valve 170, 2-3 shift timing valve 180 and accumulators A1 to A4, and an electronic control unit (illustrated. Solenoid valve SO whose operation is controlled according to the shift operation of the shift lever and the vehicle speed
L1, SOL2, SOL3, SOL4, and the above-mentioned valves and accumulators are the above-mentioned hydraulic clutches L / U, Co, C1, C2 and hydraulic brake B.
o, B1, B2, etc. are connected as shown.

In the above structure, the shift lever 11 is P
When it is shifted to the position, the manual valve 10 is shifted to the P range, and the operation of the shift lever to the P position is performed by the P position switch (not shown).
The solenoid valve SOL2 is turned on and closed by the electronic control unit, and the solenoid valves SOL1 and SOL3 are turned off and opened. As a result, the R range circuit 2 is operated by the manual valve 10.
02, D range circuit 203, S range circuit 204, and L range circuit 205 are disconnected from the line pressure supply circuit 201 and connected to the reservoir. Therefore, the 2-3 shift valve in which the hydraulic clutch C1 connected to the D range circuit 203 is connected to the reservoir via the manual valve 10 and the hydraulic clutch C2 is in the inoperative state (the spool is pushed by the spring). 90, the D range circuit 203 and the manual valve 10, or the R range circuit 202 and the manual valve 10 to connect to the reservoir, and the hydraulic brake Bo is in the operating state (the spool is pushed against the spring). 4 shift valve 1
00 to the reservoir, the hydraulic brake B1 is connected to the reservoir via the inactive 2-3 shift valve 90 and the 2-3 shift timing valve 180, and the hydraulic brake B2 is activated to the 1-2 shift. The line pressure supply circuit 201 connected to the reservoir via the valve 80, the reverse control valve 110 in the inoperative state, the R range circuit 202, and the manual valve 10 and connected to the 3-4 shift valve 100 has an upper pilot. The hydraulic pressure applied to the oil chamber 101 causes 3
-4 is connected to the hydraulic clutch Co via the shift valve 100 and the inactive CO exhaust valve 150 to form a P range circuit, and the hydraulic clutch C
o, C1, C2 and hydraulic brakes Bo, B1, B2 etc. are in the operating / non-operating state (the circle is the operating state and the unmarked is the non-operating state) as shown in P mode in FIG. The gear train shown in FIG. 1 is brought into a neutral state.

When the shift lever 11 is shifted to the R position, the manual valve 10 is shifted to the R range, and the operation of the shift lever 11 to the R position is detected by an R position switch (not shown). , Solenoid valve SOL by electronic control unit
2 is turned on and closed, and the solenoid valve SO
L1 and SOL3 are turned off and opened. As a result, the line pressure supply circuit 201 is operated by the manual valve 10.
Is connected to the R range circuit 202, and the D range circuit 203, the S range circuit 204, and the L range circuit 205 are connected.
Is disconnected from the line pressure supply circuit 201 and connected to the reservoir. Therefore, the hydraulic clutch C1 and the hydraulic brakes Bo and B1 are connected to the reservoir in the same manner as the P range circuit described above, and the line pressure supply circuit 201 connected to the manual valve 10 is in the inoperative state with the R range circuit 202. The R range circuit 2 is connected at the same time as being connected to the hydraulic brake B2 via the reverse control valve 110 and the activated 1-2 shift valve 80.
Connected to the hydraulic clutch C2 via 02, and 3-4
The line pressure supply circuit 201 connected to the shift valve 100 is connected to the hydraulic clutch Co via the 3-4 shift valve 100 in the operating state and the CO exhaust valve 150 in the non-operating state to form an R range circuit. The hydraulic clutches Co, C1, C2 and the hydraulic brake B.
The operating / non-operating states of o, B1, B2, etc. are as shown in the R mode of FIG. 3, and the reverse gear train is completed in the gear train shown in FIG.

When the shift lever is shifted to the N position, the manual valve 10 is shifted to the N range, and the operation of the shift lever to the N position is detected by an N position switch (not shown), so that the electronic The solenoid valve SOL2 is turned on by the control device.
N is closed and solenoid valves SOL1,
SOL3 is turned off and opened. As a result, in the manual valve 10, the R range circuit 202, the D range circuit 203, the S range circuit 204, and the L range circuit 205 are cut off from the communication with the line pressure supply circuit 201 in the same manner as the P range circuit described above. Connected.
Therefore, the hydraulic clutches C1 and C2 and the hydraulic brake B
o, B1, B2 are connected to the reservoir in the same manner as the P range circuit described above, and the 3-4 shift valve 1
The line pressure supply circuit 201 connected to 00 is connected to the hydraulic clutch Co via the 3-4 shift valve 100 in the operating state and the CO exhaust valve 150 in the non-operating state to form an N range circuit, The operating / non-operating states of the hydraulic clutches Co, C1, C2 and the hydraulic brakes Bo, B1, B2, etc. are as shown in the N mode of FIG. 3, and the gear train shown in FIG. 1 is brought into the neutral state.

When the shift lever 11 is shifted to the D position, the manual valve 10 is shifted to the D range, and the operation of the shift lever 11 to the D position is detected by a D position switch (not shown). , ON / OFF of the solenoid valves SOL1 to SOL3 according to the vehicle speed is controlled by the electronic control unit as follows (D
1), (D2), (D3), and (D4) are controlled as described, and the line pressure supply circuit 201 is connected to the D range circuit 203 by the manual valve 10.
The R range circuit 202, the S range circuit 204, and the L range circuit 205 are disconnected from the line pressure supply circuit 201 and connected to the reservoir.

(D1) When the first speed command signal is transmitted from the electronic control unit In this case, the solenoid valve SOL1 is turned on and closed, and the solenoid valves SOL2 and SOL3 are turned on.
It is opened as FF. As a result, the 2-3 shift valve 90 is operated by receiving pilot pressure in the upper pilot oil chamber 91, and the 3-4 shift valve 100 is activated.
Is operated by receiving the line pressure of the line pressure supply circuit 201 into the lower pilot oil chamber 102 via the D range circuit 203 and the operating 2-3 shift valve 90. Therefore, the hydraulic clutch C2 is connected to the reservoir via the 2-3 shift valve 90 and the manual valve 10 in the operating state or the R range circuit 202 and the manual valve 10, and the hydraulic brake Bo drives the 3-4 shift valve 100 in the operating state. Connected to the reservoir via the hydraulic brake B
1 is connected to the reservoir via the 2-3 shift valve 90 in the activated state and the 1-2 shift valve 80 in the inactivated state,
1-2 shift valve 8 with hydraulic brake B2 inactive
The line pressure supply circuit 201 connected to the 3-4 shift valve 100 is connected to the reservoir via the 2-3 shift valve 90, the L range circuit 205, and the manual valve 10 which are in the 0 operation state. -4 shift valve 100 and CO exhaust valve 15 in a non-operating state
0 is connected to the hydraulic clutch Co, and the hydraulic clutch C1 connected to the D range circuit 203 is connected to the line pressure supply circuit 201 via the manual valve 10 to form a D-1 range circuit. Hydraulic clutch Co, C1, C2 and hydraulic brake Bo, B1, B
The operating and non-operating states of 2 and the like become as shown in the D-1 mode of FIG. 3, and the gear train of the first speed shift stage is completed in the gear train shown in FIG.

(D2) When the second speed command signal is transmitted from the electronic control unit In this case, the solenoid valves SOL1 and SOL2 are turned on and closed, and the solenoid valve SOL3 is turned on.
It is opened as FF. As a result, pilot pressure is applied to the pilot oil chambers 81, 91, 101 of the 1-2 shift valve 80, 2-3 shift valve 90, and 3-4 shift valve 100, and the 1-2 shift valve 80, 2-
Both the 3 shift valve 90 and the 3-4 shift valve 100 are activated. Therefore, the hydraulic clutch C1 connected to the D range circuit 203 is not connected to the manual valve 1
0 is connected to the line pressure supply circuit 201, and the hydraulic brake B1 is operated through the 2-3 shift valve 90, the operated 1-2 shift valve 80, the D range circuit 203, and the manual valve 10 through the line pressure. Supply circuit 201
Is connected to the hydraulic brake B1 and the CO exhaust valve 150 is operated by the pressure oil supplied to the hydraulic brake B1, the 3-4 shift valve 100 in the operating state, the S range circuit 204, and the manual valve 10. The hydraulic clutch C2 is connected to the reservoir via the 2-3 shift valve 90 and the manual valve 10 or the R range circuit 202 and the manual valve 10 and the hydraulic brake Bo is in the operated state. The 1-2 shift valve 80, the line pressure supply circuit 201, and the D range circuit 203, which are connected to the reservoir via the 4 shift valve 100 and in which the hydraulic brake B2 is in the operating state.
It is connected to the reservoir through the reverse control valve 110, the R range circuit 202, and the manual valve 10 in which both spools are pushed upward in the drawing by receiving both hydraulic pressures from the same direction as the acting direction of the spring, and D-2 A range circuit is formed and hydraulic clutches Co, C1, C2
The operating and non-operating states of the hydraulic brakes Bo, B1, B2, etc. are as shown in the D-2 mode of FIG. 3, and the gear train of the second speed shift stage is completed in the gear train shown in FIG.

(D3) When the third speed command signal is transmitted from the electronic control unit In this case, the solenoid valve SOL2 is turned on and closed, and the solenoid valves SOL1 and SOL3 are turned on.
It is opened as FF. As a result, pilot pressure is applied to the pilot oil chambers 81 and 101 of the 1-2 shift valve 80 and the 3-4 shift valve 100 so that the 1-2 shift valve 80 and the 3-4 shift valve 100 are both in the operating state. Further, the pilot pressure is removed from the pilot oil chamber 91 of the 2-3 shift valve 90, and the 2-3 shift valve 90 is deactivated. Therefore, the hydraulic brake Bo is connected to the reservoir via the activated 3-4 shift valve 100, and the hydraulic brake B1 is connected to the reservoir via the inactivated 2-3 shift valve 90 and the 2-3 shift timing valve 180. When the hydraulic brake B2 is connected, the hydraulic pressures from the 1-2 shift valve 80 and the line pressure supply circuit 201 and the D range circuit 203 are received in the same direction as the spring action direction, and the spool is pushed upward in the drawing. Reverse control valve 110
The hydraulic clutch C1 connected to the reservoir via the R range circuit 202 and the manual valve 10 and the D range circuit 203 is connected to the manual valve 1
0 to the shift valve 90 connected to the line pressure supply circuit 201, and the hydraulic clutch C2 is in the inoperative state.
It is connected to the line pressure supply circuit 201 via the range circuit 203 and the manual valve 10, and the hydraulic clutch Co is in the non-operating state by the CO exhaust valve 150 and the operating state by the 3-4 shift valve 100, and the 3-4 shift is performed. It is connected to the line pressure supply circuit 201 connected to the valve 100 to form a D-3 range circuit, and the hydraulic clutches Co, C1 and C2 and the hydraulic brakes Bo, B1 and B2 are in the operating / non-operating state. In the gear train shown in FIG. 1, the gear train for the third speed is completed.

(D4) When the fourth speed command signal is transmitted from the electronic control unit In this case, the solenoid valve SOL3 is turned on and closed, and the solenoid valves SOL1 and SOL2 are turned on.
It is opened as FF. As a result, both the 2-3 shift valve 90 and the 3-4 shift valve 100 are deactivated and the low coast modulator valve 1
40, orifice control valve 160, low inhibit valve 170, 2-3 shift timing valve 180, pilot oil chambers 141, 161, 171, 1
The pilot pressure is applied to 81 respectively,
In addition, D is placed in the pilot oil chamber 82 of the 1-2 shift valve 80.
Range circuit 203 and 2-3 non-actuated shift valve 9
Pilot pressure is applied through 0. Therefore, the 2-3 shift valve 90 in which the hydraulic brake B1 is not operated
And the 2-3 shift timing valve 180 is connected to the reservoir, and the hydraulic brake B2 is in the operating state of the 1-2 shift valve 80, the inactive state of the reverse control valve 110, the R range circuit 202, and the manual valve 1.
0 is connected to the reservoir, the hydraulic clutch Co is connected to the reservoir via the inactive CO exhaust valve 150 and the inactive 3-4 shift valve 100, and is connected to the D range circuit 203. The hydraulic clutch C1 is connected to the line pressure supply circuit 201 via the manual valve 10, and the hydraulic clutch C2 is in a non-actuated 2-3 shift valve 90 and the D range circuit 203.
And the line pressure supply circuit 20 via the manual valve 10.
3-4 in which the hydraulic brake Bo is not operated
3-4 shift valve 100 through shift valve 100
Connected to the line pressure supply circuit 201 connected to
-4 range circuit is formed, hydraulic clutch Co,
The operating and non-operating states of C1, C2 and the hydraulic brakes Bo, B1, B2, etc. are as shown in the D-4 mode of FIG. 3, and the gear train of the fourth speed is completed in the gear train shown in FIG. To be done.

In this case (running in the gear train of the fourth speed)
When the vehicle speed becomes equal to or higher than the set vehicle speed, the lockup signal is transmitted from the electronic control unit to cause the solenoid valve S to move.
OL4 is turned on and closed. As a result, the hydraulic pressure adjusted by the modulator valve 130 from the line pressure is applied to the pilot oil chamber 71 of the lockup control valve 70 through the lockup signal valve 60 in the operating state. Therefore, the lockup control valve 70 is activated, the supply pressure from the secondary regulator valve 50 is supplied to the torque converter T through the passages 74 and 72, and the passage 73 is connected to the reservoir. Therefore, the torque converter T
The lock-up piston 211 is pressed against the front front cover 212 by the differential pressure across the lock-up piston 211, and the lock-up hydraulic clutch L / U is directly connected.

When the vehicle speed becomes lower than the set vehicle speed, the lockup signal is not transmitted from the electronic control unit, the solenoid valve SOL4 is turned off and opened, the lockup control valve 70 is deactivated, and the passage Hydraulic pressure is supplied to the front of the lockup piston 211 through 73, and working oil is discharged from the rear of the lockup piston 211 through a passage 72 toward an oil cooler (not shown), pushing the lockup piston 211 rearward. The hydraulic clutch L / U is released from the direct connection state.

When the shift lever 11 is shifted to the S position, the manual valve 10 is shifted to the S range, and the operation of the shift lever 11 to the S position is detected by an S position switch (not shown). , ON / OFF of the solenoid valves SOL1 to SOL3 depending on the vehicle speed is controlled by the electronic control unit as follows (S
1), (S2) and (S3), the line pressure supply circuit 201 is connected to the D range circuit 203 and the S range circuit 204 by the manual valve 10, and the R range circuit 202, The L range circuit 205 is disconnected from the line pressure supply circuit 201 and connected to the reservoir.

(S1) When the first speed command signal is transmitted from the electronic control unit In this case, the solenoid valve SOL1 is turned on and closed, and the solenoid valves SOL2 and SOL3 are turned on.
It is opened as FF. As a result, (D
As in the case of 1), the 2-3 shift valve 90 and the 3-4 shift valve 100 are operated, and the above-mentioned (D
As in the case of 1), hydraulic clutch C2 and hydraulic brake B
o, B1, B2 are connected to the reservoir, hydraulic clutches Co, C1 are connected to the line pressure supply circuit 201 to form an S-1 range circuit, and hydraulic clutches Co, C1, C2 and hydraulic brake Bo, B1, B2
The operating and non-operating states such as shown in FIG. 3 are as shown in the S-1 mode, and the gear train for the first speed is completed in the gear train shown in FIG.

(S2) When the second speed command signal is transmitted from the electronic control unit In this case, the solenoid valves SOL1 and SOL2 are turned on and closed, and the solenoid valve SOL3 is turned on.
It is opened as FF. As a result, (D
As in the case of 2), the 1-2 shift valve 80, the 2-3 shift valve 90, and the 3-4 shift valve 100 are both activated. Therefore, as in the case of (D2) described above, the hydraulic clutch C1 and the hydraulic brake B1 are connected to the line pressure supply circuit 201, and the hydraulic clutch C
o is the CO exhaust valve 150 that is activated by the supply of pressure oil to the hydraulic brake B1 and 3-
It is connected to the line pressure supply circuit 201 via the 4-shift valve 100, the S range circuit 204, and the manual valve 10, and the hydraulic clutch C2, the hydraulic brake Bo, and the hydraulic brake B2 are used as reservoirs as in the case of (D2) described above. When connected, an S-2 range circuit is formed, and hydraulic clutches Co, C1, C2 and hydraulic brakes Bo, B are connected.
The operating / non-operating states of 1, B2, etc. are as shown in the S-2 mode of FIG. 3, and the gear train of the second speed is completed in the gear train shown in FIG. In this case, since the hydraulic clutch Co is in the operating state, unlike the case of (D2) described above, the idling of the one-way clutch F1 is suppressed and the engine braking becomes effective.

(S3) When the third speed command signal is transmitted from the electronic control unit In this case, the solenoid valve SOL2 is turned on and closed, and the solenoid valves SOL1 and SOL3 are turned on.
It is opened as FF. As a result, (D
As in the case of 3), the 1-2 shift valve 80 and the 3-4 shift valve 100 are activated and the 2-3 shift valve 90 is deactivated, and the above-mentioned (D
As in the case of 3), the hydraulic brakes Bo, B1, B2 are connected to the reservoir and the hydraulic clutches Co, C1,
C2 is connected to the line pressure supply circuit 201 to form an S-3 range circuit, and the hydraulic clutches Co, C1,
The operating and non-operating states of C2 and the hydraulic brakes Bo, B1, B2, etc. are as shown in the S-3 mode of FIG. 3, and the gear train of the third speed is completed in the gear train shown in FIG. .

When the shift lever 11 is shifted to the L position, the manual valve 10 is shifted to the L range, and the operation of the shift lever 11 to the L position is detected by the L position switch (not shown). , ON / OFF of the solenoid valves SOL1 to SOL3 depending on the vehicle speed is controlled by the electronic control unit as follows (L
1), (L2) and (L3) are controlled as described, and the line pressure supply circuit 201 is connected to the D range circuit 203, the S range circuit 204 and the L range circuit 205 by the manual valve 10. The R range circuit 202 is disconnected from the line pressure supply circuit 201 and connected to the reservoir.

(L1) When the first speed command signal is transmitted from the electronic control unit In this case, the solenoid valve SOL1 is turned on and closed, and the solenoid valves SOL2 and SOL3 are turned on.
It is opened as FF. As a result, (D
2-3 shift valve 90 as in 1) and (S1)
And the 3-4 shift valve 100 is activated, and the pilot pressure is applied from the L range circuit 205 to the pilot oil chamber 92 below the 2-3 shift valve 90 via the low inhibit valve 170 in the inoperative state. hand,
As a result, the 2-3 shift valve 90 is also activated. Therefore, as in the case of (D1) and (S1) described above, the hydraulic clutch C2 and the hydraulic brakes Bo and B1 are connected to the reservoir, and the hydraulic clutches Co and C are connected.
1 is connected to the line pressure supply circuit 201, and the hydraulic brake B2 is inactive 1-2 shift valve 80, low coast modulator valve 140 and active 2-3
It is connected to the line pressure supply circuit 201 via the shift valve 90, the L range circuit 205, and the manual valve 10 to form an L-1 range circuit, and the hydraulic clutches Co, C1, C2 and the hydraulic brakes Bo, B1, B2 are formed. The operating and non-operating states such as shown in FIG. 3 are as shown in the L-1 mode, and the gear train of the first speed is completed in the gear train shown in FIG. In this case, since the hydraulic brake B2 is in the operating state, the above-mentioned (D1),
Unlike the case of (S1), the idling of the one-way clutch F2 is suppressed and the engine braking becomes effective.

(L2) When the second speed command signal is transmitted from the electronic control unit In this case, the solenoid valves SOL1 and SOL2 are turned on and closed, and the solenoid valve SOL3 is turned on.
It is opened as FF. As a result, (D
2), 1-2 shift valve 8 as in the case of (S2)
0, 2-3 shift valve 90, 3-4 shift valve 10
0 are both activated and the L range circuit 20
5 through the low-inhibit valve 170 in the inoperative state, the pilot oil chamber 9 below the 2-3 shift valve 90.
Pilot pressure is applied to 2 and 2-3
The shift valve 90 is activated. Therefore, the hydraulic clutch C1 and the hydraulic brake B1 are connected to the line pressure supply circuit 201 as in the case of (D2) and (S2) described above, and the hydraulic clutch Co is hydraulically operated as in the case of (S2) described above. The CO exhaust valve 150 which has been activated by the pressure oil supply to the brake B1, the 3-4 shift valve 100 which is in the activated state, and the S range circuit 20.
Line pressure supply circuit 2 via 4 and manual valve 10
01, and the hydraulic clutch C2, the hydraulic brake Bo, and the hydraulic brake B2 are connected to the reservoir as in the case of (D2) and (S2) described above to form the L-2 range circuit and the hydraulic clutch Co. , C1, C2 and the hydraulic brakes Bo, B1, B2, etc. are in the operating / non-operating state as shown in the L-2 mode of FIG. 3, which is different from the case of (S2) in the gear train shown in FIG. A similar gear train for the second gear is completed.

(L3) When the third speed command signal is transmitted from the electronic control unit In this case, the solenoid valves SOL2 and SOL3 are turned on and closed, and the solenoid valve SOL1 is turned off.
It is opened as FF. As a result, pilot pressure is applied to the pilot oil chambers 81 and 101 of the 1-2 shift valve 80 and the 3-4 shift valve 100 so that the 1-2 shift valve 80 and the 3-4 shift valve 100 are both in the operating state. Each of the pilot chambers 141, 161, 171 of the low coast modulator valve 140, the orifice control valve 160, the low inhibit valve 170, and the 2-3 shift timing valve 180.
Pilot pressure is respectively applied to 181 to operate the low inhibit valve 170, and the pilot oil chamber 92 below the 2-3 shift valve 90 is connected to the reservoir via the low inhibit valve 170 in the active state. The 3-shift valve 90 is deactivated. Therefore, as in the case of (D3) and (S3) described above, the hydraulic brakes Bo, B1 and B2 are connected to the reservoir and the hydraulic clutches Co, C1 and C2 are connected to the line pressure supply circuit 201, and L- A three-range circuit is formed, and the hydraulic clutches Co, C1 and C2 and the hydraulic brakes Bo, B1 and B2 are in the activated / deactivated state as indicated by L-3 in FIG.
As shown in the mode, the gear train of the third speed is completed in the gear train shown in FIG.

By the way, in the present embodiment, in the vehicle which is traveling at a speed higher than the set vehicle speed in the fourth speed gear position of the D position, the shift lever 11 is shifted from the D position to the L position and the manual valve 10 is operated.
Is shifted from the D range to the L range, the third speed command signal is transmitted from the electronic control unit, and the low inhibit valve 170 causes the pilot oil chamber 92 below the 2-3 shift valve 90 to move from the L range circuit 205. Shut off and keep communicating with reservoir. Therefore, the manual valve 10
Although the line pressure supply circuit 201 is connected to the L range circuit 205, the 2-3 shift valve 90 is in an inoperative state, that is, pressure oil is supplied to the hydraulic clutch C2 from the D range circuit 203, and the third speed or the fourth speed. It is maintained in a high-speed operation mode that enables a shift speed, and is downshifted from the 4th speed shift stage to the 3rd speed shift stage, but is not suddenly downshifted to the 2nd speed shift stage. Overrun can be accurately prevented. Further, in a vehicle that is traveling at a speed higher than the set vehicle speed at the third speed in the D position, the shift lever 11 is shifted from the D position to the L position, and the manual valve 10 is shifted from the D range to the L range. In this case, the third speed command signal is continuously transmitted from the electronic control unit and the third speed gear is maintained.

On the other hand, the D-position 4th gear or 3
When the shift lever 11 is shifted from the D position to the L position and the manual valve 10 is shifted from the D range to the L range in a vehicle traveling at a speed lower than the set vehicle speed at the high speed shift stage, A speed command signal is transmitted from the electronic control unit, and the low inhibit valve 170 is switched to the inoperative state in which the pilot oil chamber 92 below the 2-3 shift valve 90 is connected to the L range circuit 205. Therefore, in this case, as the line pressure supply circuit 201 is connected to the L range circuit 205 by the manual valve 10, the 2-3 shift valve 90 is in an operating state, that is, pressure oil is discharged from the hydraulic clutch C2. Then, the mode is switched to the low speed operation mode that enables the first speed or the second speed and the downshift is performed from the fourth speed or the third speed to the second speed. However, in this case, since the vehicle speed is not high, a rapid deceleration shock and an overrun of the engine do not occur even if the vehicle is downshifted from the 4th gear stage or the 3rd gear stage to the 2nd gear stage. Brake and driving force can be obtained.

Further, in this embodiment, the above-mentioned (D
As is clear from the description of 4), in the vehicle traveling at the fourth speed gear position of the D position, the solenoid valves SOL1 and SOL2 are both turned off and the solenoid valve SOL3 is turned on. Yes, low-inhibit valve 170 is a 2-3 shift valve 90
The pilot oil chamber 92 below is shut off from the L range circuit 205 and communicated with the reservoir, that is, the operating state. Therefore, if the shift lever 11 is shifted from the D position to the L position and the manual valve 10 is shifted from the D range to the L range while the L range position switch fails,
When the speed command signal is continuously transmitted from the electronic control device and the solenoid valves SOL1 and SOL2 are both turned off, the line pressure supply circuit 20 is operated by the manual valve 10.
Although 1 communicates with the L range circuit 205, the low-inhibit valve 170 in the operating state shuts off the pressure oil supply from the line pressure supply circuit 201 to the pilot oil chamber 92 below the 2-3 shift valve 90, and The 3rd shift valve 90 is maintained in the non-operating state, and the 4th speed is maintained in the gear train, so that the downshift is not performed.

When the vehicle is traveling in the 4th gear position at the D position, the solenoid valve SOL3 is turned off and the low inhibit valve 170 moves the pilot oil chamber 92 below the 2-3 shift valve 90 to the L range. Circuit 2
When the shift lever 11 is shifted from the D position to the L position with the L range position switch failing, the manual valve 1
When the line pressure supply circuit 201 communicates with the L range circuit 205 at 0, the line pressure supply circuit 201 outputs 2-
Pressure oil is supplied to the pilot oil chamber 92 below the 3 shift valve 90, the 2-3 shift valve 90 is switched to the operating state, and a circuit equivalent to the L-1 range circuit is formed, as shown in FIG. In the gear train, the gear train of the 4th speed shift stage is switched to the gear train of the 1st speed shift stage, resulting in a sudden downshift.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a gear train of a 4-speed automatic transmission with a lockup mechanism for a vehicle.

FIG. 2 is a hydraulic circuit diagram of a hydraulic control device for an automatic transmission for a vehicle according to the present invention.

FIG. 3 is a diagram showing a relationship of operation / non-operation in each mode of the hydraulic clutch and the hydraulic brake shown in FIG. 1.

[Explanation of symbols]

10 ... Manual valve, 11 ... Shift lever, 90 ...
2-3 shift valve, 92 ... pilot oil chamber, 170 ...
Low-inhibit valve, 201 ... Line pressure supply circuit,
205 ... L range circuit, SOL3 ... Solenoid valve.

Claims (1)

[Claims] 1. A manual valve which is manually operated in association with a shift lever to selectively communicate a line pressure supply circuit with each range circuit in each range, and a switch to a first speed or a second speed shift stage of a second speed or lower. It has a possible low-speed operation mode and a high-speed operation mode that can switch to a third or fourth speed or higher, and when it receives pilot pressure in the pilot oil chamber, it switches to a low-speed operation mode and the pilot pressure is eliminated. At this time, the operation is controlled by the 2-3 shift valve which is switched to the high speed operation mode and the solenoid valve corresponding to the vehicle speed, and at a low speed less than the set vehicle speed, the pilot oil chamber of the 2-3 shift valve and L which is one of the range circuits. The low range circuit is communicated, and the pilot oil chamber is disconnected from the L range circuit to communicate with the reservoir when the vehicle speed is higher than the set vehicle speed. A hydraulic control device for an automatic transmission for a vehicle, which includes an inhibit valve.