JPH0514821B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electronically controlled automatic transmission, in particular:
The present invention relates to an electronically controlled automatic transmission that smoothly performs gear shifting operations.

(Prior Art) In recent years, automatic transmissions for vehicles have been developed, and the gear shift operation of the transmission is not performed manually by the driver, but is operated by an actuator operated by fluid pressure, for example, based on commands from an electronic control device mounted on the vehicle. manipulated,
The transmission is being shifted.

Then, a pair of fluid pressure actuators that operate in the select direction and the shift direction of the transmission mechanism are provided, and a position sensor that detects the operating positions of these pair of actuators is provided to accurately know the operating position of the actuator. JP-A-58-170954 discloses a proposal for a transmission actuator that enables position control.

(Problem to be Solved by the Invention) In the above proposal, fluid pressure is applied to the fluid pressure actuator by a solenoid valve, so if the synchronizing capacity of the transmission mechanism or the dog tooth module becomes large, a large amount of pressure may be generated during gear shifting. Impact forces may be applied, which may damage the above-mentioned components and shorten their lifespan.

In addition, if the shift actuator and select actuator are configured using a differential pressure type piston,
Even if two or more solenoid valves are turned on or off at the same time, the cylinder piston position will deviate due to the response difference and will be out of the detection range of the position switch.
There also arises a disadvantage that the shift position becomes unknown.

Therefore, it is an object of the present invention to provide a duty control solenoid on-off valve between a tank and a solenoid valve for driving a shift actuator and a select actuator, so that the duty control solenoid on-off valve is installed between a tank and a solenoid valve for driving a shift actuator and select actuator. To provide an electronically controlled automatic transmission in which duty operation is performed to limit sudden movement of a piston to perform smooth automatic gear shifting operation.

Another object of the present invention is to provide an automatic transmission of the type described above, in which the operating position of the shift actuator is detected by a stroke sensor, and preferably the operating position of the select actuator is also detected by the stroke sensor. Therefore, it is an object of the present invention to provide an electronically controlled automatic transmission in which the shift position or select position can be clearly grasped.

(Means for Solving the Problems) According to the present invention, in an electronically controlled automatic transmission that controls fluid pressure by an electronic control device to operate the transmission in a shift direction and a select direction to control a shift, and a stroke sensor that detects the position in the select direction, a driving solenoid valve disposed between the fluid pressure source and the shift and select actuator, and a confluence point where the return pipes of both actuators join together. There is provided an electronically controlled automatic transmission characterized by having an electromagnetic on-off valve disposed between an electromagnetic valve and a fluid pressure tank, and a control means for duty-controlling the on-off valve.

(Operation) When a gear shift command is given, a shift is made and a target gear is selected. During gear shift, if the vehicle speed is not zero, the duty control electromagnetic on-off valve is operated on duty after synchronization to suppress sudden piston movement. After that, when the shift is completed and the clutch is engaged, the release of hydraulic pressure from the pressure oil supply line to the tank is prohibited to prevent the gear from slipping out.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic block diagram showing the relationship between an automatic transmission and an electronic control device, and FIG. 2 is a configuration diagram showing a transmission actuator.

In Fig. 1, 1 is a parallel shaft gear type transmission;
Reference numeral 2 denotes an electronic control unit composed of a microcomputer, which calculates an appropriate gear for the transmission, controls signals for driving the transmission, signals for controlling the clutch, etc. 3 and 4 are respectively an input shaft rotation sensor and an output shaft rotation sensor (vehicle speed sensor) of the transmission, and 5 and 6 are shift actuators of a transmission actuator that drives the transmission 1, and It is a select actuator. 7 is a select lever, which sends a signal based on the select position to the electronic control device 2 from the select switch 7a, and 8 is an accelerator pedal, which sends a signal corresponding to the amount of pedal depression to the electronic control device 2 by an accelerator sensor 8a. input.

The electronic control unit 2 includes a central processing unit (CPU) that performs arithmetic processing based on input signals, various memories (MEMO) that store arithmetic results and register values, and store shift maps, as well as control signals. It has an I/O that serves as an input/output circuit.

In FIG. 2, numeral 10 indicates a shift actuator, with L, N ₁ and R stages, or 2, N ₂ and 3 stages,
Or switch between 3 positions: 4, N ₃ , 5 stages, or 6, N ₄ , empty stage. Reference numeral 20 indicates a selection actuator, which switches between four positions: N ₁ , N ₂ , N ₃ , and N ₄ .

Reference numeral 30 indicates a shift stroke sensor, which detects the position of the piston rod 1b of the shift actuator 10, which has a cylinder 1a and a piston rod 1b.

Reference numeral 40 indicates a select stroke sensor, and the piston rod 1 of the select actuator 20 has a cylinder 2a, a piston rod 2b, etc.
Shift stroke sensor 30 and select stroke sensor 40
The detection signal from is input to the electronic control device 2 described above.

V ₁ and V ₂ are solenoid valves that operate the shift actuator 10, and V ₃ , V ₄ and V ₅ are solenoid valves that operate the select actuator 20.
Pin is the main hydraulic power source, P is the hydraulic power source for the normal hydraulic circuit system, and P' is the hydraulic power source for the emergency hydraulic circuit system. Note that the present invention includes not only hydraulic pressure but also pneumatic pressure. Ve ₁ is an emergency solenoid valve of the select actuator 20,
Ve ₂ and Ve ₃ are emergency solenoid valves of the shift actuator 10, and V ₄ is a solenoid valve for switching the hydraulic circuit system.

Although the above-described embodiments have been described including an emergency hydraulic circuit system, the present invention can also be applied to systems that do not include an emergency hydraulic circuit system.

Further, _V6 is an electromagnetic on-off valve for duty control, and is placed downstream of the confluence of the return pipes of both actuators. In addition to on/off control, this electromagnetic on-off valve performs a predetermined duty operation.
The hydraulic oil is returned to the tank T.

Next, FIGS. 3 and 4 show a characteristic diagram showing the relationship between the shift stroke value (TMS) and time, and a characteristic diagram showing the relationship between the top gear rotational speed (TMN) and time, respectively. As is clear from these figures, during a shift, these values are:

(1) Before synchronization (0 to t ₁ ) (dTMS)/dt≠0, (dTMN)/dt=0 0≦TMS<a ₁ (2) During synchronization (t ₁ to t ₂ ) (dTMS)/dt= 0, (dTMN)/dt≠0 TMS=a ₁ (3) After synchronization (t ₂ ~ _{t 3} ) (dTMS)/dt≠0, (dTMN)/dt=0 a ₁ ≦TMS≦a _Second , FIG. 5 is a flowchart showing an example of the processing of this embodiment, and the control of the present invention will be explained with reference to FIG.

First, the shift stroke value, select stroke value, engine speed, vehicle speed, top gear rotation speed are read into the electronic control unit 2 from the shift stroke sensor 30, select stroke sensor 40, input shaft rotation sensor 3, output rotation sensor 4, etc. (Step S1).

When a gear shift command is issued from the electronic control unit 2 (step S2), the clutch is released (step S2).
S3), V ₃ , V ₄ or V ₅ are turned on, V ₆ is turned off and the select operation is held (step
S4).

V ₁ and V ₂ are turned on and shift actuator 10
The gear is disengaged (step S5), V ₃ , V ₄ or V ₅ is turned on and the selection actuator 20 is selected to the target gear (step S6).

It is determined whether the vehicle speed is zero or not based on the signal from the output rotation sensor 4 (step S7), and if it is not zero, _V1 or _V2 is turned on and _V6 is operated on duty (step S8).

When the vehicle speed is zero, V ₁ or V ₂ is turned on and V ₆
After the is turned off, the process moves to step S13 (step S9).

Next, it is determined whether the synchronization operation is during synchronization or after synchronization (step S10), and during synchronization, _V1 or _V2 is turned off, and _V6 is turned off (step S10).
S11), a normal shift operation is performed.

After synchronization, V ₁ or V ₂ is turned off,
V ₆ is activated on duty, which limits the sudden movement of the piston to prevent damage to the dog teeth (step S12) and maintains this condition until the shift stroke is complete (step S12).
S13).

When the shift stroke is completed according to the signal from the shift stroke sensor 30, _V6 is turned on (step S14) and the clutch is engaged (steps S15, S16).

After that, V ₁ , V ₂ , V ₃ , V ₄ or V ₅ is turned off (step S17), and V ₆ is turned off (step S17).
S18).

(Effects of the Invention) As explained in detail above, the present invention provides an electromagnetic on-off valve that duty-controls the flow rate of hydraulic oil and returns the hydraulic oil to the tank, so that the operation of the actuator can be controlled gently. This has the effect of preventing damage to the transmission mechanism. Since this electromagnetic on-off valve is disposed downstream of the confluence of return oil of both actuators, the operation of both actuators can be controlled with one valve.

Further, according to the present invention, since a stroke sensor is provided to detect the select position, in conjunction with the action of the solenoid valve that performs duty control, it is possible to prevent deviations in actuator operation due to response differences, thereby ensuring reliable shift control. There is also an effect that can be achieved.

[Brief explanation of the drawing]

Figure 1 is a schematic block diagram showing the relationship between the automatic transmission and the electronic control device, Figure 2 is a configuration diagram showing the transmission actuator, Figure 3 is a diagram of the relationship between shift stroke value and time, and Figure 4 is a diagram showing the relationship between shift stroke value and time. FIG. 5, which is a diagram showing the relationship between top gear rotational speed and time, is a flowchart of an example of the operation of this embodiment. 1...Transmission, 2...Electronic control device, 10...
Shift actuator, 20... Select actuator, 30... Shift stroke sensor, 40... Select stroke sensor, V ₆ ...
...Solenoid on-off valve.

Claims (1)

[Claims] 1. In an electronically controlled automatic transmission that controls fluid pressure by an electronic control device to operate the transmission in the shift direction and select direction to control gear changes, a stroke sensor that detects the position in the shift direction and the select direction, respectively, and a fluid pressure a driving solenoid valve disposed between the source and the shift and select actuator, and a solenoid disposed between the confluence point where the return pipes of both actuators merge and the solenoid valve and the fluid pressure tank. An electronically controlled automatic transmission characterized by having an on-off valve and a control means for duty-controlling the on-off valve.