JPS6213538B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a kick-down device that detects sudden depression of an accelerator pedal and downshifts an automatic transmission.

Conventionally, as shown in FIG. 1, when the accelerator pedal 1 is suddenly depressed from the solid line position A to the imaginary line position B in the figure, a kick-down switch 2 has been provided which is turned on in conjunction with the depression. 2 is turned on, the automatic transmission (not shown) is automatically downshifted to ensure the acceleration performance of the automobile. A kick-down device is well known (Japanese Patent Laid-Open No. 52-81469). (see official bulletin).

By the way, in automatic transmissions equipped with this type of kickdown device, kickdown (downshift) is performed when accelerating to overtake a vehicle, etc.
When the road surface is frozen in winter or in cold regions, there is a risk that the wheels may slip due to a sudden increase in rotational speed.

The present invention has been made to solve this problem, and it is an object of the present invention to provide a kickdown device for an automatic transmission that can disable the kickdown of an automatic transmission by detecting the frozen state of the road surface. The purpose is

That is, in the present invention, a detection means for detecting the frozen state of the road surface from the outside air temperature is provided, and
The basic feature is that the kickdown device is provided with a control section that disables the kickdown device when the detection means detects freezing of the road surface.

Hereinafter, the present invention will be described in more detail with reference to the illustrated embodiments.

In Figure 2, 3 is an automatic transmission (not shown)
This downshift valve is an electromagnetic switching valve, which operates the armature 4a in the direction of arrow A in the figure by supplying power to the solenoid 4, and pushes the valve body 3a against the spring force of the return spring 3b. As a result, the first port 3c connected to the power source is switched from the drain port 3d to the operating port 3e to automatically shift down the automatic transmission.

The solenoid 4 of the downshift valve 3 is
Its positive electrode is connected to the positive electrode of the battery 5, and between the two positive electrodes is an ignition switch 6, which is turned on by sudden depression of the accelerator pedal, in order to control the operation of the downshift valve 3. A normally open kick-down switch 7 (see Fig. 1 and 2), a normally closed relay switch that turns on when the road surface is frozen, and a freeze detection switch 8 that is turned on and off regardless of whether the freeze detection switch 8 is on or off. A manual changeover switch 9 for turning off the solenoid 4 for the battery 5 and disabling kickdown is connected in series in the above order.

For the freeze detection switch 8, there is provided a temperature sensor 10 that detects an outside temperature that approximates the road surface temperature;
The freezing temperature setting device 11 is preset to the temperature at which the road surface freezes (~0°C), and the output of the temperature sensor 10 is compared with the output of the freezing temperature setting device 11 to determine whether the outside temperature is below the set temperature. A comparator 12 that sometimes turns off the freeze detection switch 8 is provided to constitute a control section that disables the downshift valve 3 when the road surface is frozen even when the kickdown switch 7 is turned on.

With the above configuration, in normal conditions when the road surface is not frozen, the normally closed freeze detection switch 8 is on, so the kick-down switch 7 will not be on unless the changeover switch 9 is manually turned off. When an automobile is overtaking and accelerating, the solenoid 4 is energized and the downshift valve 3 is operated to shift down the automatic transmission.

On the other hand, in cold weather when the road surface is frozen, the outside temperature detected by the temperature sensor 10 drops below the freezing temperature set by the freezing temperature setting device 11, and the comparator 12 switches the freezing detection switch. Turn off 8. As a result, the switch 7 turns on and off.
Irrespective of whether it is off or not, the solenoid 4 is cut off from the battery 5, the downshift valve 3 cannot operate, and the automatic transmission is no longer able to kick down. Therefore, a sudden increase in the rotational speed during acceleration is avoided, and the risk of slipping due to frozen road surfaces can be reliably prevented.

In addition, in the above, the kickdown switch 2 (see 7 in FIG. 2) as shown in FIG. 1 was used, but
The kickdown may be performed by detecting a sudden depression of the accelerator pedal based on a change in the opening degree of a throttle valve in the intake system that is linked to the accelerator pedal, or a variation in the intake negative pressure accompanying this.

Furthermore, as shown in phantom lines in FIG. 2, a manual short-circuit switch 13 is installed in parallel with the freeze detection switch 8.
may be connected. If this short circuit switch 13 is provided, even if the outside temperature has fallen below the freezing temperature, if the road surface is not frozen, the short circuit switch 13 can be turned on.
The freeze detection switch 8 can be short-circuited, and when the kickdown switch 7 is turned on, the downshift valve 3 can be operated to ensure acceleration.

As is clear from the above description, the present invention detects a frozen road surface using a temperature sensor and disables a kick-down device of an automatic transmission in response to the detection means. The present invention provides a kick-down device for an automatic transmission, characterized in that it is provided with a control section for controlling the automatic transmission.

According to the present invention, by adding a simple configuration,
It is possible to reliably prevent the risk of slipping accidents caused by kicking down when the road surface is frozen.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the operation of a kick-down switch, and FIG. 2 is a control circuit diagram of a kick-down device for an automatic transmission according to an embodiment of the present invention. 3... Downshift valve, 4... Solenoid, 7
…Kick-down switch, 8…Freezing detection switch, 10…Temperature sensor, 11…Freezing temperature setting device,
12... Comparator.

Claims (1)

[Claims] 1. In an automatic transmission that detects sudden depression of the accelerator pedal and uses a kick-down device to downshift, the automatic transmission receives a signal from a temperature sensor that detects outside air temperature, and disables the kick-down device when the outside air temperature exceeds a set value. 1. A kick-down device for an automatic transmission, comprising a control section for operating the automatic transmission.