JPH0560157A - Braking actuator - Google Patents

Abstract

PURPOSE:To provide a braking actuator which is miniaturized and light and is excellent in response as well as capable of braking independently of each wheel. CONSTITUTION:A brake caliper 1 is provided with an actuator 2 provided with a motor 3. This actuator 2 is connected to a driving piston 7 which converts the rotary motion of the motor 3 into linear motion through a converter and is provided with a liquid chamber 10 between the driving piston 7 and a pad pressing piston 9 which presses the brake pad in the brake caliper 1. The diameter of the driving piston 7 is smaller than the diameter of the pa pressing piston 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake actuator, and more particularly to a brake actuator in which a brake fluid pressure is controlled by a motor.

[0002]

2. Description of the Related Art Conventionally, an auxiliary power source other than a brake pedal force is required when antilock or so-called traction control is performed in a vehicle.

Conventionally, various actuators have been used as such a power generation source.
The one described in Japanese Patent No. 266050 is known. As shown in FIG. 3, a power cylinder 54 is connected to an accumulator 50 in which pressure is accumulated by an electric pump 51 via electromagnetic plungers 52 and 53. The hydraulic pressure of the power cylinder 54 is the brake pipe 5.
It is configured to be transmitted to the cylinder of each brake caliper 55 via 6.

The electromagnetic plungers 52 and 53 are individually controlled by signals from a central controller (not shown),
The cylinder pressure of the brake caliper 55 is controlled.

By the way, the brake control of each wheel is ideally performed for each wheel, but in the above-mentioned method, a uniform brake fluid pressure is applied to the four wheels, so that the brake control is best performed. Difficult to do.
Further, piping from the accumulator to each brake is required, and an electromagnetic plunger for brake control is required.

To solve these problems, there is one disclosed in Japanese Patent Laid-Open No. 64-21229. As shown in FIG. 4, the power of the motor 40 is transmitted to the ball screw 44 through the speed reducer 43 and the electromagnetic clutch 41, and the friction pad 46 is pressed by the slider 45 that engages with the ball screw 44 and slides. It is supposed to do.

[0007]

However, in the above-mentioned conventional device, the motor and the speed reducer are large-scaled in order to obtain a sufficient braking force. Moreover, an electromagnetic clutch is provided to compensate for the deterioration of response due to the increase in the size of parts and the complexity of the structure. However, this may further complicate the structure and increase the unsprung load. ..

The present invention has been made in view of the above matters, and it is a technical object to provide a brake actuator which is not only capable of independently braking each wheel but also lightweight and small and excellent in response. To do.

[0009]

In order to solve the above technical problems, the present invention has the following constitution. That is, an actuator equipped with a motor is provided in the brake caliper, and this actuator connects the driving piston through a conversion unit that converts the rotational motion of the motor into a linear motion, and also a pad that presses the brake pad in the brake caliper. A liquid chamber is provided between the pressing piston and the driving piston, and the diameter of the driving piston is smaller than the diameter of the pad pressing piston.

[0010]

The torque of the motor presses the driving piston through the speed reducer and the converter to increase the liquid pressure in the liquid chamber.

Then, the pad pressing piston for pressing the brake pad provided in the brake caliper moves by the hydraulic pressure, and the brake is applied. Here, since the diameter of the driving piston is smaller than the diameter of the pad pressing piston, a boosting action can be obtained, and a large braking force can be obtained without lowering the reponse.

[0012]

Embodiments of the present invention will be described with reference to FIGS. 1 and 2. The brake caliper 1 is movable in the rotation axis direction of the disk 12 by a known guide device (not shown).

The brake caliper 1 is equipped with a pad 11 and a pad pressing piston 9 for pressing the pad 11 against the disk 12. An actuator 2 is integrally provided on the brake caliper 1. This actuator 2 is integrated with appropriate rigidity regardless of whether it is completely integrated or separable.

The actuator 2 is composed of a body 2a having a cylinder 2b inside, an electric motor 3 and the following elements. That is, the screw 5 is located at the center of the cylinder 2b, and one end of the screw 5 is the shaft 5a. A spur gear 4b is attached to the shaft 5a. The motor 3 is fixed to the body 2a, and a spur gear 4a fitted to the motor shaft is used.
Is engaged with the spur gear 4b. The spur gears 4a and 4b constitute the speed reducer 4.

A large diameter portion 5b is provided on a part of the shaft 5a, and a thrust bearing 5c is provided between the large diameter portion 5b and the frame 2a. This allows
Even if the screw 5 is stressed in the F direction shown by the arrow, the screw 5 rotates smoothly. A slider 6 is accumulated on the screw 5 through a large number of balls (not shown). The slider 6 is slidably fitted in the cylinder 2b and slides in the cylinder 2b when the screw 5 rotates. The screw 5 and the slider 6 constitute a converter 13.

A driving piston 7 is fitted in the cylinder 2b in a gas-liquid tight manner.
Is closely attached to the slider 6. A coil spring S is provided between the drive piston 7 and the end of the cylinder 2b.
It is designed to bias in the direction. The frame is provided with a screw hole penetrating into the cylinder, and a screw 6a for preventing the slider 6 from rotating is screwed into the screw hole. The slider 6 is provided with a groove along its sliding direction so as to be engaged with the screw 6a.

A liquid chamber 10 is provided between the drive piston 7 and the pad pressing piston 9 and is filled with brake fluid. The liquid chamber 10 communicates with the reservoir through the hole R. The diameter of the drive piston 7 is smaller than the diameter of the pad pressing piston 9, and the area ratio is preferably about 1/3 to 1/10.

As shown in FIG. 2, the motor 3 is designed so that its rotation torque and rotation direction are controlled by a command from the central controller 21. The rotation torque and direction are determined by signals from a pedal force sensor and a stroke sensor provided on the brake pedal 22, and when the brake pedal 22 is strongly depressed, the torque is rotated with a stronger torque.

An example of operation will be described below. When the brake pedal 22 is stepped on, a signal corresponding to the pedaling force is sent to the central control unit 21.
The central controller 21 outputs a predetermined drive signal to rotate the motor.

Then, the motor 3 rotates the screw 5 via the speed reducer 4 to move the slider 6 in the direction opposite to the arrow F. Then, the driving piston 7 integrated with the slider 6 also moves in the same direction.

Following this, the pad pressing piston 9 is also pressed with a force of several times to ten times that of the driving piston 7, and the brake pad 11 is pressed against one surface of the disc 12. The stress in the thrust direction at this time is held by the thrust bearing 5c. The reaction force causes the brake caliper 1 to move in the F direction, and the other brake pad (not shown) is pressed against the other surface of the disc by the brake caliper reaction portion.

Since the diameter of the driving piston 7 is set smaller than the diameter of the pad pressing piston 9 in this way, the response is superior to that using a multiple reduction gear and the electromagnetic clutch is not required. .. For this reason, it was possible to achieve a significant reduction in size and weight.

Incidentally, if the signals from the slip sensors provided on the wheels as well as the signals from the pedaling force sensor and the stroke sensor are also input to the central control device 21, it is possible to perform traction control as well. Of course.

[0024]

According to the present invention, the rotation of the motor is reduced and at the same time the conversion portion converts it into a linear motion to activate the driving piston and press the brake pad in the brake carrier. Since the diameter of the driving piston is set to be smaller than the diameter of the pad pressing piston by providing a liquid chamber between the driving piston and the driving piston, independent braking control can be performed for each wheel and, of course, multiple speed reducers. The response is superior to the one using, and the electromagnetic clutch is unnecessary.

Therefore, the weight can be reduced to a small size, and the unsprung load can be reduced as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a sectional view of a conventional device.

FIG. 4 is a brake system diagram of a conventional device.

[Explanation of symbols]

 1 brake caliper, 2 actuator, 3 motor, 4 reducer, 5 screw, 6 slider, 7 driving piston 8 brake pad, 9 pad pressing piston, 10 liquid chamber, 13 conversion part.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Kei Kunimi 5-4-71 East, Hanyu City, Saitama Prefecture Akebono Brake Central Technical Research Institute (72) Inventor Tatsuo Ogawara 5-4-171 East, Hanyu City, Saitama Prefecture Company Akebono Brake Central Technology Laboratory (72) Inventor Tadashi Kobayashi 5-4-171 Higashi, Hanyu City, Saitama Prefecture Akebono Brake Central Technology Laboratory

Claims (1)

[Claims] 1. A brake caliper is provided with an actuator provided with a motor, and this actuator connects a driving piston through a conversion part for converting a rotational motion of the motor into a linear motion, and a brake pad in the brake caliper is connected. A brake actuator, wherein a liquid chamber is provided between a pad pressing piston to be pressed and the driving piston, and a diameter of the driving piston is smaller than a diameter of the pad pressing piston.