JPS5834256A - Differential movement limitation unit - Google Patents

Abstract

PURPOSE:To perform differential movement limitation promptly and accurately by computing the rotary angle speed of left and right drive shafts by a rotary sensor installed and judging slip conditions from the difference of the anglular speeds and by applying a differential movement limitation only to the drive wheels on a slip generation side with an auxiliary brake unit. CONSTITUTION:Rotary sensors 4a and 4b are installed on left and right wheels 3a and 3b. The rotary angular speeds of the wheels 3a and 3b are computed from the signals transmitted from the sensors 4a and 4b. The slip conditions of left and right drive wheels 2a and 2b are judged by comparing the signals with a specified value of a reference voltage generator 7 and a differential drive system 1 is operated. As a typical example of the above operation, if the left drive wheel 2a is subjected to a slip condition, an auxiliary brake 12 is designed to brake the drive wheel 2a as specified so that a greater power may be applied to the right drive wheel 2b. This construction makes it possible to perform differential movement limitation promptly and accurately in the early stage of slip generation.

Description

Detailed Description of the Invention The present invention is attached to a differential mechanism of a vehicle such as an automobile, and when one of the left and right drive wheels slips, the differential mechanism transmits force to the slipping drive wheel. This invention relates to a differential limiting device that limits the increase in the number of wheels, and has been improved to perform its operation quickly and accurately.

This differential limiting device focuses on the fact that the presence or absence of slip between the left and right drive wheels can be determined from the rotational speed difference between the two, and applies an auxiliary brake to the slipping drive wheel when slip occurs based on this rotational speed difference. A patent application filed by the applicant in 1984-31 is based on the electronic III model.
No. 79 has already been proposed.

However, in this method based on the difference in rotational speed, the relatively clear value of the difference needed to judge slipping cannot be obtained until after the drive wheels have rotated to a certain extent, so it takes time to judge whether slipping has occurred. Therefore, there is a problem that the responsiveness of the differential limiting action is correspondingly similar. In addition, when turning, the differential mechanism distributes control so that the outer wheels rotate faster than the inner wheels due to the road resistance of the tires, and in this case it is necessary to set the differential limiting device so that it does not operate. However, since the manner of turning is various and miscellaneous, and the rotational speed difference between the left and right drive wheels during turning also covers a wide range, the range in which the differential limiting device operates should be set to a large value other than the above range. Become. This further accelerates the above-mentioned response delay, resulting in malfunctions being more likely to occur.

The present invention has been made in view of the above circumstances, so that sudden rotational fluctuations when the left and right drive wheels slip can be quickly and accurately determined by detecting the rotational angular acceleration. Considering that the acceleration is much larger than the angular acceleration caused by the difference in rotational speed between the inner and outer wheels when turning, the presence or absence of slip is determined based on the rotational angular speed of the left and right drive wheels, and the differential limiting action is quickly applied. Moreover, it is an object of the present invention to provide a differential differential limiting device that can be used accurately.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, reference numeral 1 denotes a differential mechanism, and an axle 3a that transmits power from the differential mechanism 1 to left and right drive wheels 2a, 2b. , 3b are each provided with a rotation sensor 4a.

4b is provided. The rotation sensor 4a detects the rotational speed, that is, the rotational angular velocity.The signal from the sensor 4a is differentiated by a differentiating circuit 5a to calculate the rotational angular acceleration, and this value is used by the comparator 6a to generate a reference voltage. Vessel 7
is compared with the set value, and if it is larger than that, it is determined that a slip has occurred.

Similarly, the other rotation sensor 4b has a differentiating circuit 5b.

Next, the comparator 6b equipped with the reference voltage generator 7 determines whether or not a slip has occurred. Here, such rotational angular acceleration may be detected in the case of sudden acceleration, and the value of the reference N pressure generator 7 is set to eliminate this.

On the other hand, a brake pipe 118° 11b having a check valve 10.10 for preventing backflow is piped from a master cylinder 9 operated by a brake pedal 8 to the left and right drive wheels 2a, 2b, and is connected to this normal brake hydraulic circuit. An auxiliary brake device 12 for differential limiting is added. This device 12
is piped from the hydraulic pump 13 through a pipe 14 to solenoid valves 15a and 15b on the left and right driving wheels, and the solenoid valve 15a is further connected to the brake pipe 1 through a pipe 16a.
It is piped to the downstream side of the check valve 10 of 1a, and is electrically connected to the comparator 6a, so that it is opened in response to a signal from the comparator 6a. Further, the solenoid valve 15b is constructed in exactly the same manner.

To explain the operation of the differential limiting device of the present invention configured in this way, when the vehicle is running, the left and right drive wheels 2a,
The rotational angular acceleration of 2b is detected by the rotation sensor 4a.

4b, and comparators 6a and 6b determine whether or not a slip has occurred.

Therefore, for example, when the left drive wheel 2a slips, since the above-mentioned rotational angular acceleration is determined by a small angular displacement, this is determined at the beginning of the slip, and the output signal from the comparator 6a opens the solenoid valve i5a. Operate. Therefore, the auxiliary brake hydraulic pressure from the hydraulic pump 13 is supplied to the left drive wheel 2a to apply a predetermined brake, and as a result, the differential mechanism 1
It is determined that the resistance has increased rather than decreased due to the slip, and a large amount of power is transmitted to the right drive wheel 2b. Even when the right drive wheel 2b slips, the differential limiting action is similarly performed at the initial stage of occurrence of the slip.

As is clear from the above description, according to the present invention, the slip of one of the left and right drive wheels 2a, 2b is determined based on the rotational angular acceleration of the wheels, so the determination is made at the beginning of the gas slip and the differential limiting action is performed. is done very responsively. In addition, the rotational angular acceleration during turning is sufficiently small, and the setting value for judgment can be determined to exclude cases of sudden acceleration that are commonly used, so the setting value can be small, eliminating malfunctions and improving response. This will further promote sexual improvement.

[Brief explanation of the drawing]

The drawing is a block diagram showing an embodiment of the apparatus according to the present invention. 1...Differential mechanism, 2a...Left drive wheel, 2b...
Right drive wheel, 3a, 3b--Axle, 4a, 4b-
... Rotation sensor, 5a, 5b... Differential circuit, 6a,
6b...Comparator, 12...Auxiliary brake device. Patent applicant: Fuji Heavy Industries Co., Ltd. Representative Patent Attorney: Nobuo Kona, Patent Attorney: Susumu Murai

Claims (1)

[Claims] A rotation sensor is provided in the power transmission system from the differential mechanism to the left and right drive wheels, and the rotational angular acceleration is calculated from the rotation speed measured by the rotation sensor, and the slip occurrence state is determined for each of the left and right drive wheels. 1. A differential limiting device characterized in that the auxiliary brake device applies a predetermined brake only to the drive wheels of the differential limiting device.