JPS6331030B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic transmission for a vehicle, and more particularly to a shift control device for relieving engagement shock when the shift position is changed from a neutral state to a drive state. .

Conventionally, when an automatic transmission is shifted from a neutral state to a drive state, the gear position of the automatic transmission is in the 1st gear state with the largest gear ratio, so the torque fluctuation at the time of engagement is the same as that of the 1st gear. This increases the ratio and causes an unpleasant engagement shock.

In order to alleviate the above-mentioned engagement shock, conventionally, for example, in Japanese Patent Publication No. 50-709, a control system for an automatic transmission that combines an electric type and a hydraulic type has been constructed, and the gear position of the transmission can be set in advance when changing gears. A control means is disclosed that temporarily sets a gear position, which is different from a finally set gear position and requires less shift shock, to an intermediate shift position for a period of time.

In addition, Japanese Patent Application Laid-Open No. 53-93527 discloses that when starting a stopped vehicle, the gear position is changed to a higher speed gear for a predetermined short period of time when switching to the driving range, and after the predetermined time elapses, A control device for switching to normal gear position is disclosed. In both of the above examples, so-called timer control is employed in order to alleviate the shock when switching and controlling the automatic transmission.

Furthermore, a method is usually used in which the engagement shock is relaxed by a cushion plate or an accumulator that are part of the engagement device; There was a problem that the capacity had to be increased.

The present invention has been made in view of the above, and it is an object of the present invention to provide a shift control device for an automatic transmission that can alleviate the engagement shock when shifting from neutral to drive position by extremely simple means. .

Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic diagram of an electronically controlled automatic transmission. However, since this is already known, it will be briefly explained here.

The rotation of engine 1 is controlled by lock-up clutch 2a.
The torque is transmitted to the planetary gear unit 3 via the torque converter 2 including is transmitted to. The speed change of the planetary gear unit 3 is performed by the hydraulic pressure controlled by the solenoid valve 7 and the servo mechanism 8, and the operation of the lock-up clutch 2a of the torque converter 2 is controlled by the solenoid valve 7. Ru. In this example, an automatic transmission mechanism is mainly composed of a torque converter 2 and a planetary gear unit 3.

The solenoid valve 7 is controlled by the microcomputer ECU, which receives a detection signal from the throttle position sensor 9 that detects the throttle opening and a detection signal from the vehicle speed sensor 4. and a signal from a shift position sensor 10 that detects the shift position of the shift lever. Furthermore, this microcomputer
The ECU also receives signals from a knock sensor, engine water temperature sensor, altitude sensor, pattern select switch, brake sensor, etc., but they are not shown in the diagram.

In this electronically controlled automatic transmission, the signal from the throttle position sensor 9 that detects the throttle opening and the signal from the vehicle speed sensor 4 that detects the vehicle speed are input to the microcomputer ECU. The microcomputer determines the speed to be set according to the set gear shift line, and also sends a signal to the solenoid valve 7 to select the gear position.

Now, such control is performed in conventional electronically controlled automatic transmissions, but in this example control, in addition to the control described above, detection from the shift position sensor 10 that detects the shift position is performed. When a signal is input to the microcomputer ECU to change the shift position from the neutral position to the drive position, the planetary gear unit 3 first shifts to the 2nd position.
A new control device has been installed that allows the vehicle to operate in either high speed or third speed.

The operation of this control device will be explained based on FIG.
0 and starts the routine shown in FIG.

That is, in step 1, it is determined based on the signal from the vehicle speed sensor 4 whether the vehicle speed is zero. If this is NO, the process moves to normal control, and if Yes, the process moves to step 2. In this step 2, it is determined whether the throttle opening is in the idling state (fully closed) based on the signal from the throttle position sensor 9. If NO, the process moves to step 4, and if YES, the process moves to step 3.
In step 3, it is determined whether the shift position has been shifted from the neutral position to the drive position based on the signal from the shift position sensor 10, and if NO, the process returns to step 1.
If Yes, move to step 5. In step 5, the planetary gear unit 3 is set to 3rd speed, and then the process returns to step 1. In step 4, the planetary gear unit 3 is set to 1st speed, and then normal control is started.

In this way, if the gear position of the planetary gear unit 3 is controlled to be selected between 2nd speed and 3rd speed when the shift position is changed from neutral to drive position while the engine is idling and the car is stopped, , the engagement shock during shifting can be made very small.

Then, when the throttle is depressed to start the car, the throttle position sensor 9 detects this, so the gear position of the planetary gear unit 3 is returned to 1st gear, and then control is performed according to the normal gear shift line. If you return it to its original position, you will be able to make the car vibrate without feeling any shift shock when engaged.

Incidentally, FIG. 3 shows the control action when the planetary gear unit is set to second speed when shifting from the neutral to the drive position. However, in this case, the control operation is the same as that shown in FIG. 2 except that the planetary gear unit is set to second speed in step 5, so a description thereof will be omitted.

That is, in the present invention, when the vehicle speed is below a predetermined value and the throttle opening is below a predetermined value, when the shift lever is operated from neutral to drive position, the gear stage of the automatic transmission mechanism is first set to 2nd or 3rd gear. The automatic transmission's shift control device can alleviate the unpleasant engagement shock when shifting from neutral to drive position, and it also eliminates the need for a large-capacity cushion plate or accumulator to improve the shock. It has an excellent feature that it is no longer necessary.

After shifting from N range to D range, the vehicle is held in high gear while stopped regardless of the time, so the output torque from the transmission decreases, and the reaction force from the drive shaft also decreases, so the engine The mount reaction force can be reduced, which reduces idle vibration. Furthermore, when the throttle opening exceeds a predetermined value, the engine is downshifted by one step before reaching high speed, reducing the shock, and on the other hand, when the vehicle speed exceeds a predetermined value, it is possible to prevent reverse travel on a slope. Furthermore, because it returns to the normal gear without using timer control like in the past, it is more intuitive to humans and causes less shock.

Note that not only the case of shifting the shift lever from neutral to the drive position, but also the case of shifting from neutral to low range etc. belong to the technical scope of the present application.

[Brief explanation of the drawing]

The drawings show an embodiment embodying the present invention; FIG. 1 is an explanatory diagram showing the configuration of an electronically controlled automatic transmission; FIG. 2 is an explanatory diagram showing a flowchart of the control operation of this embodiment; FIG. 3 is an explanatory diagram showing another flowchart of the control action of this example. 2... Torque converter, 3... Planetary gear unit, 4... Vehicle speed sensor, 7... Solenoid valve, 9... Throttle position sensor,
10...Shift position sensor, ECU...Microcomputer.

Claims (1)

[Claims] 1. An automatic transmission mechanism having a fluid coupling and a planetary gear, a frictional engagement device that achieves gear shifting of the automatic transmission mechanism, and a hydraulic control device that supplies or discharges fluid pressure to the frictional engagement device; In an automatic transmission equipped with a control device that electrically controls the hydraulic control device, it is recognized that the shift position is changed from a neutral position to a running position when the throttle opening is below a predetermined value and the vehicle speed is below a predetermined value. When this occurs, while controlling the gear position of the automatic transmission mechanism to a second gear position or higher,
1. A shift control device for an automatic transmission, characterized in that the control device is configured to perform control to return to a normal gear position when it is recognized that a throttle opening or a vehicle speed has exceeded a predetermined value.