JPH0670462B2 - Hydraulic control of automatic transmission - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hydraulic control device for an automatic transmission of a vehicle.

[Prior Art] A hydraulic circuit is automatically controlled by the output of a microcomputer based on input signals such as engine load, engine speed, vehicle speed, etc., and each hydraulic actuator that drives a clutch mechanism and a shift rod is operated by the hydraulic circuit. Such an automatic transmission has already been proposed, for example, in JP-A-54-96659.

However, in the conventional hydraulic control device for an automatic transmission, there is no hydraulic switching valve that interlocks with the selector lever, and in the unlikely event of an electrical failure, the electromagnetic switching valve malfunctions and shifts to a certain shift stage. There was a problem that you could not return to the neutral position from the state. In order to eliminate such a problem, it is proposed that the main electromagnetic control valve is inserted and connected between the electromagnetic switching valve that operates each hydraulic actuator and the hydraulic power source.
This may also fail due to electrical failure.

[Problems to be Solved by the Invention] In view of the above problems, an object of the present invention is to provide a manual hydraulic on-off valve mechanically connected to a selector lever, and if the selector lever is set to N range, malfunction due to malfunction occurs. It is to provide a hydraulic control device for an automatic transmission that can be eliminated.

[Means for Solving the Problems] In order to achieve the above object, the structure of the present invention has a pair of three-position operation type hydraulic actuators for individually driving a plurality of shift rods between the end chamber and the hydraulic source. In the automatic transmission in which the electromagnetic switching valve of is connected and connected, and the gear meshing position is selected by the electromagnetic switching valve, the hydraulic on-off valve mechanically linked to the selector lever is inserted between the hydraulic power source and each electromagnetic switching valve. Connect the hydraulic on-off valve to the output port connected to the electromagnetic switching valve in the selector lever D range connected to the hydraulic source, and to connect the selector port N range to cut off the output port from the input port and connect to the tank. It is a thing.

[Operation] The hydraulic on-off valve is in the D range, the input port connected to the oil pressure source is connected to the output port connected to each electromagnetic switching valve, and the both end chambers of each three-position hydraulic actuator are hydraulically operated by a pair of electromagnetic switching valves. Selectively connected to source or tank.

When the electromagnetic switching valve has stopped operating due to an electrical failure, the output port is disconnected from the input port and connected to the tank when the hydraulic opening / closing valve is switched to the N range by the selector lever. Therefore, each end chamber of each hydraulic actuator will be connected to the tank regardless of the position of the electromagnetic switching valve, and by manually returning each hydraulic actuator to the neutral position, the drive wheels of the vehicle will be The rotational connection with the engine is released.

[Embodiment of the Invention] As shown in FIG. 1, a hydraulic opening / closing valve A is inserted and connected between a hydraulic power source 12 and a hydraulic control circuit B of a hydraulic actuator C for driving a shift rod. The hydraulic on-off valve A is constructed by fitting the spool 2 into the valve chamber 16 of the housing 3, and the holes 2a provided at the end of the spool 2 are provided with P, R, N, D, 2, L (not shown).
A selector lever for switching between the ranges (operating modes) is connected. In order to keep the spool 2 in a predetermined range, a ball 6 that is selectively biased by a spring 4 into two recesses 7 of the spool 2 is held in a cylindrical portion provided in the housing 3. The valve chamber 16 is provided with an input port 8 connected to the hydraulic power source 12, an output port 15 connected to each electromagnetic switching valve 31 to 36 of the hydraulic control circuit B, and a port 13 constantly connected to the tank 17. On the other hand, the spool 2 is provided with an annular groove 9 connected to the input port 8 and the output port 15 and an annular groove 10 connected to the drain port 14 in the D range.

The hydraulic control circuit B is composed of 6 to 3 pairs of electromagnetic switching valves 31 to 36. Solenoid switching valves 31-36 are solenoids 31a-3
When the solenoid 6a is demagnetized, it is in the state shown, and when the solenoids 31a to 36a are excited, it switches from the state shown and the output port 15
Pilot hydraulic pressure from the passage 22 connected to the valve acts on the spool.

The three-position operation type hydraulic actuator C is a hydraulic actuator 41 that drives a shift rod 54 that obtains a shift between the fourth gear and the fifth gear, and a shift rod 55 that obtains a shift between the second gear and the third gear.
And a hydraulic actuator 43 for driving a shift rod 56 for obtaining a reverse speed and a first speed. Since the hydraulic actuators 41 to 43 have exactly the same configuration, only the hydraulic actuator 41 will be described.

The hydraulic actuator 41 has a small diameter cylinder 58 and a small diameter piston.
59, the cylindrical large-diameter piston 61 is fitted into the large-diameter cylinder 62, respectively. In addition, the large-diameter piston 61
60 is fitted and abuts or is integrally formed with the small diameter piston 59. Small diameter piston 59 is shift rod 54
Combined with.

When pressure oil is supplied from the hydraulic pressure source 12 to both the end chamber 57 of the small diameter cylinder 58 and the end chamber 63 of the large diameter cylinder 62, the shift rod 54
Is held in the neutral position shown. Although not shown, the intermediate chamber formed between the large-diameter piston 61 and the small-diameter piston 59 when they are separated from each other is always connected to the tank 17.

In order to connect each end chamber of each hydraulic actuator 41-43 to the hydraulic source 12 or the tank 17, an electromagnetic switching valve 31-36 is provided in each end chamber.
Are connected. That is, in the case of the hydraulic actuator 41, pressure oil is sent from the passage 22 connected to the output port 15 to the end chamber 63 of the large diameter cylinder 62 via the electromagnetic switching valve 31, or the oil in the end chamber 63 is transferred to the tank 17. It is returned to the passage 21 leading to. Further, pressure oil is sent from the passage 22 through the electromagnetic switching valve 32 to the end chamber 57 of the small diameter cylinder 58, or the oil of the end chamber 57 is passed through the passage 21.
Returned to. The electromagnetic switching valves 31 and 32 are normally in the state shown in the figure by the force of the return springs 31b and 32b, and the end chambers 63 and 57 are connected to the tank 17 respectively.
Is configured to drive the spool against the force of the return springs 31b and 32b when energized to connect the end chambers 63 and 57 to the hydraulic power source 12.

Although not shown, one end of each of the shift rods 54 to 56 is projected from the gear box to the outside, and a suitable tool is engaged with the one end so that it can be moved in the axial direction. Since the configuration is not directly related to the configuration of the present invention, the description is omitted.

Next, the operation of the device of the present invention will be described. When traveling normally, that is, when the selector lever is in the D range, as shown in FIG. 1, the recess 7 on the right side of the spool 2 of the hydraulic opening / closing valve A is engaged with the ball 6 of the day tent mechanism 5. At this time, pressure oil is supplied from the hydraulic pressure source 12 to the port 8, the annular groove 9 and the port 15.
It is supplied to the passage 22 via. On the other hand, the passage 21 is connected to the tank 17. Solenoid switching valve that constitutes hydraulic control circuit B
31 to 36 are selectively excited by the microcomputer according to the vehicle speed, engine speed, engine load, etc., and one of the hydraulic actuators 41 to 43 is driven to the right or left to achieve the optimum gear shift.

Now, when the electromagnetic switching valve 35 is excited, the pressure oil of the hydraulic pressure source 12 is sent to the end chamber 63 of the hydraulic actuator 43 via the passage 22 and the electromagnetic switching valve 35, and the shift rod 56 is generated by the intermediate piston 60 and the small diameter piston 59. While being pushed to the right, the oil in the end chamber 57 is returned to the tank 17 via the electromagnetic switching valve 36 and the passage 21, and the meshing of the first speed gear is reached.

When the electromagnetic switching valve 35 is demagnetized and the electromagnetic switching valve 36 is excited, the pressure oil of the hydraulic source 12 is sent to the end chamber 57 of the hydraulic actuator 43 via the passage 22 and the electromagnetic switching valve 36, and the small-diameter piston 59 and large The shift rod 56 is pushed to the left by the radial piston 61, and the oil in the end chamber 63 is returned to the tank 17 through the electromagnetic switching valve 35 and the passage 21, and the meshing of the reverse gear is achieved.
When the electromagnetic switching valves 35, 36 are excited, pressure oil is sent to the both end chambers 63, 57 and returned to the neutral position shown in the figure. In this way, by exciting one or both of the pair of electromagnetic switching valves 31, 32, 33, 34, 35, 36 provided in the hydraulic circuits of the hydraulic actuators 41 to 43, the hydraulic actuators 41 to 43 are excited. The operating position can be switched to three positions.

Now, due to the abnormal operation of the electromagnetic switching valves 31 to 36 due to the failure of the microcomputer, the hydraulic actuators 41 to 43 are
When it becomes impossible to return the neutral position to the neutral position, when the selector lever is switched to the N range, the spool 2 moves from the illustrated state to the right, and the ball 6 of the day tent mechanism 5 is engaged with the recess 7 on the left side. . At this time, the annular groove 9 connected to the input port 8 is blocked from the output port 15, and the annular groove 10 connects the output port 15 and the port 14 to each of the passages 21 and 22.
Is connected to the tank 17.

Therefore, even if the spools of the solenoid operated directional control valves 31 to 36 are in any positions, the two end chambers 6 of the hydraulic actuators 41 to 43 are
Since 3,57 are connected to the tank 17, the shift rods 54-56 can be manually returned to the neutral position shown, which allows the gear transmission to be in the neutral position, i.e. the rotational coupling between the engine and the propulsion shaft. You can shut off the vehicle and take the vehicle to a repair shop.

[Effects of the Invention] As described above, the present invention inserts and connects a pair of electromagnetic switching valves between the end chamber and the hydraulic source of each three-position operation type hydraulic actuator that individually drives a plurality of shift rods. In the automatic transmission that selects the gear meshing position with the electromagnetic switching valve,
A hydraulic on-off valve mechanically interlocking with the selector lever is inserted and connected between the hydraulic power source and each electromagnetic switching valve, and the hydraulic on-off valve outputs the input port connected to the hydraulic source to the electromagnetic switching valve in the D range of the selector lever. Since it is connected to the port and the output port is disconnected from the input port and connected to the tank in the N range of the selector lever, the following effects can be obtained.

When the electromagnetic switching valve that constitutes the hydraulic control circuit malfunctions due to a failure of the energizing circuit, the hydraulic open / close valve inserted and connected between the hydraulic control circuit of the hydraulic actuator and the hydraulic power source is operated by the selector lever in the D range N When switching to the range, the hydraulic control circuit and both end chambers of the hydraulic actuator are disconnected from the hydraulic source and connected to the tank, so if the shift rod is manually returned to the neutral position, the meshing state of the gears of the transmission is released, You can tow a vehicle to a repair shop.

[Brief description of drawings]

FIG. 1 is a block diagram of a hydraulic control device for an automatic transmission according to the present invention. A: Hydraulic on-off valve, B: Hydraulic control circuit, C: Hydraulic actuator, 2: Spool, 5: Day tent mechanism, 8: Input port, 1
5: Output port, 9, 10: Annular groove, 17: Tank, 21, 22: Passage,
31-36: Solenoid switching valve, 41-43: Hydraulic actuator, 54-
55: Shift rod

Claims (1)

[Claims] 1. A pair of electromagnetic switching valves are inserted and connected between an end chamber and a hydraulic power source of each hydraulic actuator of a three-position operation type for individually driving a plurality of shift rods, and a gear meshing is performed by the electromagnetic switching valves. In an automatic transmission for selecting a position, a hydraulic opening / closing valve mechanically interlocking with a selector lever is inserted and connected between the hydraulic power source and each electromagnetic switching valve, and the hydraulic opening / closing valve is connected to the hydraulic source in the D range of the selector lever. A hydraulic control device for an automatic transmission, characterized in that an input port is connected to an output port connected to an electromagnetic switching valve, and the N range of a selector lever shuts off the output port from the input port and connects it to a tank.