JPS5920902B2 - Overdrive device with cancel mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic transmission, and more particularly to an automatic transmission equipped with an overdrive device.

Overdrive devices that reduce the gear ratio of a transmission by a certain amount have recently attracted particular attention because they are effective in reducing fuel consumption and noise at a desired vehicle speed.

However, since the overdrive device reduces the gear ratio, there are problems in that it reduces the effectiveness of engine braking and reduces the acceleration performance of the vehicle.

Therefore, it is an object of the invention to provide an overdrive device in which the overdrive effect is dynamically released during engine braking or acceleration.

According to the present invention, the above object is to compare a vehicle speed sensor that generates a voltage according to the vehicle speed, a slot sensor that generates a voltage according to the throttle valve opening, and signals from the vehicle speed sensor and the throttle sensor. and a canceling mechanism comprising a comparator that turns on and off the overdrive drive circuit, and an overdrive cancel circuit that turns off the overdrive drive circuit in response to a throttle fully open signal and a throttle fully closed signal from the throttle sensor. This is accomplished by an overdrive device.

The overdrive device with a cancellation mechanism according to the present invention has the following features:
Equipped with an overdrive cancel circuit that de-energizes the overdrive drive circuit in response to the throttle fully open/closed signal from the throttle sensor, the overdrive is automatically canceled when acceleration is required and engine braking effect is required. canceled).

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

FIG. 1 is an electrical circuit diagram of an overdrive device according to the invention.

The AC voltage proportional to the vehicle speed generated by the vehicle speed sensor, for example, the tacho generator 10, is applied to the diodes D1 to D4.
rectified by a full-wave rectifier consisting of a capacitor c1.
It is smoothed by a smoothing circuit including c2 and supplied as a vehicle speed signal S to the negative human power of the IC comparator ICI.

A throttle signal VT from a throttle sensor, such as a potentiometer 12, for detecting the opening degree of a throttle valve (not shown) is supplied to the positive input of the ICI.

The comparator ICI compares the vehicle speed signal vS and the throttle signal VT, and when the vehicle speed signal is larger than the throttle signal, the negative output of IC1 becomes positive and the transistor Tri.

Since Tr2 is turned on, the solenoid 14 of the electromagnetic valve that controls the overdrive mechanism is energized, and the transmission enters overdrive.

In the shift diagram of FIG. 2, this indicates that the vehicle speed is on the right side of the solid line with respect to the opening degree of the throttle valve at that time.

Since the negative output of the comparator IC1 becomes positive and the positive output of IC1 becomes negative at the same time, the transistor Tr3 is turned off.

As a result, hysteresis appears in the shift diagram of FIG.

That is, only when the vehicle speed signal S becomes smaller than the previous throttle signal VT by the amount of hysteresis, the negative output of the comparator C1 becomes negative, and the transistor Tri.

Tr2 is turned off, the overdrive solenoid 14 is deenergized, and the transmission is released from overdrive.

Since the throttle signal VT is also supplied to the positive input of the IC comparator IC2, the throttle valve is fully opened and the throttle signal VT becomes the set voltage V of the resistor voltage divider 16.
When it becomes larger than a, the positive output of IC2 becomes positive and turns on transistor Tr4.

As a result, the vehicle speed signal S entering the comparator IC1 decreases, so the overdrive is canceled as described above.
be done.

Therefore, the acceleration performance of the vehicle is improved.

Since the throttle signal VT is further supplied to the negative input of the IC comparator IC3, when the throttle valve is fully closed and the throttle signal VT becomes smaller than the set voltage vb of the resistor voltage divider 16, the positive output of IC3 becomes positive. This turns on the transistor Tr5.

As a result, transistors Tri and Tr2 are turned off,
Since the overdrive solenoid 14 is deenergized, the overdrive is released.

Therefore, even during engine braking, the overdrive is released, the gear ratio is increased, and the effect of engine braking is increased.

In this way, the resistive voltage divider 16, the IC comparator IC2゜transistor Tr4 and the resistive voltage divider 16, the IC comparator IC3,
The transistor Tr5 receives the throttle signal V when the throttle valve is fully open and when the throttle valve is fully open, respectively, as described above.
An overdrive cancel circuit 20 is configured to turn off the solenoid 14, which is an overdrive drive circuit, in response to S.

Transistor Tr6. Tr7. A voltage regulator including Tr8 stabilizes the voltage of batch IJ 18a and supplies a constant voltage VC to a circuit including each IC comparator.

Furthermore, the Zener diode D5 absorbs overvoltage to prevent overvoltage from being applied to the negative input of the comparator C1.

Note that the throttle valve fully closed and fully open signals may be detected using a switch attached to an accelerator pedal or an accelerator link system.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of an electric circuit of an overdrive device with a canceling mechanism according to the invention. FIG. 2 is a shift diagram for the device of FIG. 1. 10... Vehicle speed sensor, 12... Throttle sensor, IC1, IC2, IC3... Comparator, 14... Overdrive solenoid, 20
...Overdrive cancel circuit.

Claims (1)

[Claims] 1. A vehicle speed sensor that generates a voltage according to the vehicle speed, a throttle sensor that generates a voltage according to the throttle valve opening, and signals from the vehicle speed sensor and the throttle sensor are compared to turn on/off the overdrive drive circuit. An overdrive device with a cancellation mechanism, comprising a comparator, and an overdrive cancel circuit that turns off the overdrive drive circuit in response to a full throttle signal from the throttle sensor and a full throttle signal.