JPH04136979U - wiper control device - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to a wiper control device for vehicles, and its purpose is to prevent motor burnout and transistor deterioration when wiper motor lock occurs in intermittent wiper mode. It is something to do. [Configuration] A one-rotation detection switch that connects an FET 6 in series to the wiper motor 3d and switches contacts 3a, 3b and 3a when the wiper rotates once;
When the state of this one rotation detection switch is detected and the contact 3a or 3b is not switched within a predetermined time, the IC5 having a motor rotation speed detection means that turns off the FET6 turns off the FET6 and stops energizing the wiper motor 3d. It is configured to do this.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a device that operates vehicle wipers intermittently at regular intervals when the amount of rainfall is low. The present invention relates to a wiper control device having the following functions.

0002

[Conventional technology]

Conventionally, the control device that controls the intermittent operation of wipers cuts off the power to the wiper motor. Generally, relays were used as a means of connecting. Therefore, intermittent operation Not only do relays sometimes make noise, but they also open and close contacts, which puts pressure on their durability. It was a problem. Therefore, a transistor connected in series with the wiper motor The current is controlled by turning on and off the transistor to make it non-contact, and this transistor is turned off. When the power is cut off, the transistor connected in parallel with the wiper motor is turned on. , which performs power generation control to release the current generated by the wiper motor rotating inertia. are increasingly being offered.

0003

[Problem that the idea aims to solve]

However, in the wiper control device using the above transistor, the motor lock If this occurs, the excessive current may burn out the motor or cause the transistor to deteriorate. However, there were issues such as:

0004 This invention solves these conventional problems, and is designed to improve the wiper motor lock. Excellent wiper control system that prevents motor burnout and transistor deterioration when The purpose is to provide a

[0005]

[Means to solve the problem]

In order to solve the above problems, this invention is a wiper motor that drives the wipers of vehicles, etc. a switching semiconductor connected in series to the wiper motor and the switch; a control circuit for operating a switching semiconductor; and a control circuit for detecting one rotation of the wiper motor. When the rotation detection switch and the one rotation time of the above wiper motor reach a predetermined value, A wiper control device with a motor rotation speed detection means that turns off the switching semiconductor. It constitutes.

[0006]

[Effect]

Therefore, when a load is applied to the wiper due to an external factor, one rotation of the wiper motor If the time becomes longer than the set value and the motor locks up in the worst case, the motor rotation speed will be detected. Since the switching semiconductor is turned off by the output means, motor burnout and motor breakdown due to overcurrent can be avoided. This has the effect of preventing deterioration of the transistor.

[0007]

【Example】

The wiper control device of the present invention will be explained below with reference to an embodiment of FIG. 1 is an on-board battery, 2 is a power switch linked to the key switch, and 3 is a wiper motor. Contacts 3a and 3b are located on the cam plate that decelerates the rotation of the motor 3d as a one-rotation detection switch, and normally the contact 3b is on the side. When the wiper motor 3 starts rotating, it switches to the contact 3a side, and after one rotation, it switches to the cross contact 3b side. Note that one revolution of the cam plate corresponds to one stroke of the wiper blade. 6 and 7 are N-channel type power MOS field transistors (hereinafter referred to as FETs), which are used as switching semiconductors. FET6 is connected in series with motor 3d, while FET7 is connected in parallel to short circuit motor 3d. When the one rotation detection switch is connected to the contact 3b side, the transistor 4 is turned off and H is output to the port _P4 of the IC5, and when it is connected to the contact 3a, the transistor 4 is turned on. L is output to port _P4 of IC5. IC5 is an IC that generates an ON signal for FET6 at a constant cycle when the wiper is intermittently operating, and also indicates the timing to turn off FET6 when the wiper motor is locked. 8 is a wiper switch that sets the wiper operating mode in four stages: off, intermittent (INT), low, and high.

Next, to explain the operation in the above configuration, when the wiper switch 8 is set to intermittent (INT) with the switch 2 closed, the port P ₃ of the IC 5 is turned on as shown in FIG. 2(a). It is grounded and an instruction to generate an on signal for intermittent operation is given to IC5. Then, as shown in FIG. 2(b), L is output from the port _P1 of the IC5 at a constant cycle. Then, the transistor 9 is turned off, the gate of the FET 6 becomes H, and the FET 6 starts energizing the motor 3d. At the same time, as shown in FIG. 2(c), L is output from port _P2 of IC5 in synchronization with the signal from port _P1 . When the motor 3d rotates, the contact on the cam plate switches from 3b to 3a, turning on the transistor 4 and holding the output to the port _P4 of the IC5 at L. When the cam plate completes one rotation corresponding to one stroke of the wiper blade, the contact closes again to the 3b side, the transistor 4 is turned off, and the output to the port _P4 of the IC5 becomes H. At this time, H is output from port P ₁ of IC5, FET 6 is turned off, and energization to motor 3d is terminated. Instead, H is output from port P ₂ of IC5, FET 7 is turned on, and motor 3d is turned off. The motor 3d is quickly stopped by performing dynamic braking to release the generated current generated by the inertial rotation of the motor 3d. Thereafter, similarly to the above, after a certain period of time, the starting signal L for the motor 3d is output from the port _P1 of the IC5, the motor 3d rotates, and the intermittent operation of stopping the energization by switching from the contact point 3a to 3b is repeated. It will be done.

[0009] Since FETs 6 and 7 are used to control the energization of the motor 3d, Unpleasant noise is prevented by eliminating mechanically operated contacts such as relays, and the cross-FET In step 7, the motor 3d is short-circuited when the power is stopped to shorten the braking time, so the inertia force It is possible to improve the durability of the device by reducing unnecessary force caused by

0010 Next, lock the motor 3d in the intermittent (INT) mode of the wiper switch 8. Regarding the operation of preventing burnout of the motor 3d and prevention of transistor deterioration due to the phenomenon, see Figure 3. Block diagram showing the function of the motor rotation speed detection means built into IC5 This is explained by:

[0011] As mentioned above, (a) IC5 is connected to port P₁to L, turn on FET6 and turn on the mode. When power is applied to the wiper motor 3d, the wiper motor built-in 1 rotation detection switch does not switch to contact 3a, and port P of IC5_FourIf the input signal of remains H ( (hereinafter referred to as case A), motor 3d continues to rotate even when switching from contact 3b to 3a. It locked in the middle and did not switch to contact 3b even after a predetermined period of time and the port P of IC5_Fourentry Two cases are assumed where the force signal remains at L (hereinafter referred to as case B). In case (A), IC5 first turns (b) 1 rotation detection switch to contact 3a side. (c) After a certain period of time has elapsed, (d) Press the 1 rotation detection switch again. (e) Detects motor lock and closes the IC5 port. To P₁outputs L from , turns off FET6 and cuts off the power to motor 3d, In case (B), IC5 (b) 1-turn switch switches to contact 3a side. (h) After a certain period of time has passed, (i) the one-turn switch moves to the contact 3b side. Recognizes that it is not switched, (e) detects motor lock, and connects port P of IC5. ₁ outputs L from , turns off FET6, cuts off power to motor 3d, and turns off motor 3d. This prevents deterioration of burnt out transistors.

0012

[Effect of the idea]

As described above, the wiper control device of the present invention connects the wiper motor and the wiper motor. FET, which is a switching semiconductor connected in series to the A control circuit consisting of transistors that operate the body, circuits built into an IC, etc. , a one-rotation detection switch that detects one rotation of the motor, and a one-rotation detection switch that detects one rotation of the motor. means for recognizing the state of the switch, and the state of the one rotation detection switch does not change for a predetermined period of time. means for recognizing this and a means for turning off the switching semiconductor based on the above recognition. The motor rotation speed detecting means built in the IC consists of a protection means and a motor rotation speed detection means. Therefore, the lock of the wiper motor is detected by the motor rotation speed detection means and the motor is burnt out. , it is possible to prevent deterioration of the transistor.

[Brief explanation of drawings]

[Fig. 1] A circuit diagram of an embodiment of the wiper control device of the present invention.

[Figure 2] (a), (b), (c), (d) Timing chart showing the same operation

[Figure 3] Block diagram explaining the operation of the IC when the motor is locked

[Explanation of symbols]

3 Wiper motor 3a, 3b contacts 4,9 Transistor 5 IC 6,7 FET

Claims (1)

[Scope of utility model registration request] 1. A wiper motor that drives at least a wiper of a vehicle, a switching semiconductor connected in series to the wiper motor, a control circuit that operates the switching semiconductor, and a one-rotation detector that detects one rotation of the wiper motor. A wiper control device comprising a switch, and motor rotation speed detection means that detects the state of the one rotation detection switch and turns off the switching semiconductor when one rotation time of the wiper motor reaches a predetermined value.