JPH0872702A - Electric operational braking device - Google Patents

Abstract

PURPOSE: To provide an electric operational braking device with high safety capable of surely operating a brake under any conditions by selectively transmitting operational force on the high input side to the braking device when a one-way clutch with a simple mechanism is assembled in the electric operational braking device and input from an electric system and a mechanical system is operated at the same time. CONSTITUTION: A lever 18 is moved via a mechanical transmission system when a stepping-in quantity of a brake pedal becomes larger than a specified value so as to connect it to a one-way clutch. Thereafter a retainer 19 is also rotated in the same direction, and rotation of the lever 18 is transmitted to a reversible screw shaft 10, and then a piston 8 is moved so as to start the brake. Under this condition the high output can be directly transmitted to the reversible screw shaft 10 since the rotation of the reversible screw shaft is allowed only in the input direction at the one-way clutch, when the high output is received from the motor side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrically operated brake device, and more particularly to an electrically operated brake device in which a mechanism for operating a brake by an operating force of a mechanical system is incorporated. Relates to a highly safe, compact and lightweight electrically operated brake device in which the operating force on the high input side is selectively transmitted to the brake device when these inputs are simultaneously activated (this state is called select high) It is a thing.

[0002]

2. Description of the Related Art In recent years, in addition to a hydraulic brake actuation circuit, an electrically actuated brake device (so-called by-wire system) for actuating a brake by an electric signal has been developed. This electrically operated braking device converts the pedal force of the brake pedal into an electric signal and operates the braking device by a signal from an electronic control unit. Therefore, compared to the conventional hydraulic circuit type brake device, it is characterized in that the entire system can be made lighter and smaller, and further various controls of the brake device (anti-skid control, traction control,
There is an advantage that the system can be easily constructed to execute automatic brake control etc.).

An example of such an electrically operated brake device is one in which an electric motor is used as a drive source and a friction member is brought into pressure contact with a member to be braked to obtain a braking force (JP-A-63-63).
No. 266228) has been proposed. In the brake device described in the above-mentioned Japanese Patent Laid-Open No. 63-266228, the rotational torque of an ultrasonic motor that drives the rotor to rotate by elastic traveling waves generated by the piezoelectric vibrator on the stator side is controlled by the torque conversion means. The pressure contact force of the friction member with respect to the braking member is converted and transmitted to the friction material. Since this braking device changes the braking force by the ultrasonic motor to perform the braking control, it is small and lightweight, and it is possible to obtain the necessary and sufficient braking force with a small power consumption. It is expected that the effect of realizing brake control can be expected depending on the characteristics.

[0004]

However, in the above electrically operated brake device, there is a risk that no brake will be applied if any failure or abnormality occurs in the electric system. Also,
In order to avoid such a no-brake state, there is also proposed a device provided with a device that switches to a mechanical system brake by a clutch or the like when a failure occurs in the electrical system.
In such a device, there is a problem that the structure for switching the clutch becomes complicated, and it is difficult to simplify and downsize the device.

Therefore, according to the present invention, a one-way clutch having a simple mechanism is incorporated in an electrically operated brake device, and when the inputs from the electrical system and the mechanical system are simultaneously actuated, the operating force on the high input side selectively brakes. The purpose of the present invention is to propose a highly safe electrically operated brake device that can be reliably operated under any circumstances by being transmitted to the device. In this device, when the brake by the mechanical system is in the non-actuated position, the one-way clutch is released by the retainer, so that the brake operation by the electrical system is not affected at all. In the event of a failure or the like of the operating brake device, the transmission path of the mechanical system is automatically configured via the clutch, and the brake can be operated.

[0006]

Therefore, according to the present invention, the cylinder 7 formed in the caliper 4 of the brake device, the slidable piston 8 arranged in the cylinder 7, and the piston 8 are disposed in the disk 6; A reversible screw shaft 10 for reciprocating toward the rear end, a motor M for operating the reversible screw shaft 10, and an electronic control unit 3 for controlling the motor. A lever is arranged via a one-way clutch, and a mechanical force transmission system capable of operating the lever is connected to the lever, and the one-way clutch has a lever and a reversible screw shaft only when the lever is operated. Is fixed, and this is used as a means for solving the problem.

[0007]

In the normal state, the one-way clutch is not connected due to the action of the retainer. Therefore, when the driver steps on the brake pedal, the motor M is driven by a command from the electronic control device, and the piston moves due to the rotation of the reversible screw shaft against the urging force of the return spring 11a, causing the disk pad 5 to move. Press the disc 6 to apply the brake. The braking force is detected by the pressing force sensor, and the electronic control unit controls the braking force based on the detection. When releasing the brake, the motor M
Reverse rotation. For example, when a failure occurs in the electric system, the lever 1 is transmitted via a mechanical transmission system such as a handle lever.
8 is rotated as shown in FIG.
Move to the inside end. As a result, the roller 16 is pressed against the cam groove 15 by the action of the spring 17, and the one-way clutch is connected. After that, the retainer 19 also rotates integrally with the lever, and further rotation of the lever 18 is transmitted to the reversible screw shaft 10, and the piston 8 can be moved to brake. In this state, if there is a higher input from the motor side, the one-way clutch 14 allows the reversible screw shaft to rotate only in the input direction. Therefore, this high input should be transmitted directly to the reversible screw shaft. You can

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an electrically operated brake device according to an embodiment of the present invention incorporated in a caliper. 1 in the figure
Is a brake pedal, 2 is a pedaling force sensor, 3 is an electronic control unit (ECU), 4 is a brake caliper, 5 is two disc pads, and 6 is a disc arranged between the disc pads. I'm using
A description of those detailed configurations will be omitted.

A cylinder 7 is formed in the caliper 4, and a piston 8 is slidably arranged in the cylinder 7. The piston 8 is formed in a cylindrical shape with one end closed, one of the disc pads 5 is attached to the outer surface of the one end, and the piston is provided between the disc pad 5 and the piston 8. The rotation stopping means 21 and the pressing force sensor 20 are provided. A concave groove 11 is formed on the inner peripheral surface of the cylinder 7, and a return spring 11a is formed in the concave groove 11.
And an elastic body 12 that also serves as a spring seat of the return spring 11a and a seal member. The elastic body 12
Is fitted to the outer circumference of the piston 8 with a predetermined holding force, and during normal braking operation, the elastic body 12 also moves integrally with the piston 8 along with the movement of the piston 8 to bend the return spring 11a. When the brake is released, the biasing force generated by the deformation of the return spring 11a can be applied to the piston 8 via the elastic body 12.

When the clearance between the disk 6 and the disk pad 5 becomes large due to wear or the like,
The return spring 11a is deformed by the movement of the piston 8 and the elastic body 12, and the movement of the piston 8 causes the elastic body 12 to abut on the spacer 11b.
The elastic body 12 slides on the outer peripheral surface of the piston 8 until there is no clearance between the disc 6 and the disc pad 5 until is pressed by the disc 6 with a predetermined pressing force.
That is, the holding force of the elastic body 12 is the return spring 11
It is configured to be a force larger than the spring force of a and slightly smaller than the moving force of the piston. As a result, when the brake is released, the piston 8 is returned by a certain amount T by the spring 11a, and the disc pad 5 and the disc 6 are separated from each other. The clearance is automatically adjusted to a constant amount T.

At the center of the piston 8, the piston 8
A cone clutch 22 that forms a clutch in cooperation with a slope 8a formed on the inner surface of the cone clutch 22 is provided, and a nut 13 fixed to the cone clutch 22 is arranged so as to coincide with the axis of the piston 8 and is a motor. A reversible screw shaft 10 connected to the output shaft of M is screwed. A spring 24 and a thrust bearing 23 are arranged between the cone clutch 22 and the piston 8. A flange 10a is formed on the reversible screw shaft 10, and a lever 18 is rotatably arranged on the outer periphery of the flange 10a via a one-way clutch 14. The lever 18 is connected to a mechanical force transmission system (for example, a wire or the like) capable of operating the lever 18 only when the amount of depression of the brake pedal exceeds a predetermined amount.

The one-way clutch 14 has a cam groove 15 formed on the inner peripheral surface of the lever 18 as shown in FIG.
And the roller 16 and the spring 17 housed in this cam groove
When the roller 16 moves to a narrow position in the cam groove 15, the clutch is engaged and the flange 10
a and the lever 18 are fixed to each other, and the reversible screw shaft 10 can be rotated via the flange 10a by the rotation of the lever 18. Further, a protrusion 19a of the retainer 19 having the shape shown in FIG. 3 is inserted into the cam groove as shown in FIG. 4, and the one-way clutch 14 is always released by the protrusion. That is, during normal operation (state of FIG. 2), the shoulder of the retainer 19 abuts the caliper 4, and rotation to the left in the figure is prohibited. In this state, the one-way clutch 14 is locked by the protrusion 19a. The constituting roller 16 is always maintained in the released state against the biasing force of the spring 17, and as a result, the reversible screw shaft 10 can freely rotate in the forward and reverse directions in this state as shown in FIG. .

When the lever 18 is actuated by the input of the mechanical system (including the case where the electric system fails) as will be described later, the lever 18 rotates as shown in FIG. Then, the protrusion 19a moves to the end portion in the cam groove 15,
The roller 16 is pressed against the cam groove 15 by the action of the spring 17, and the one-way clutch is connected. Then lever 1
With the movement of 8, the retainer 19 also rotates in the same direction. By connecting the one-way clutch, the rotation of the lever 18 is directly transmitted to the reversible screw shaft 10, and the disc pad 5 can be moved toward the disc 6 via the reversible screw shaft to apply the brake. In this way, the electrically operated brake can also be activated by the mechanical transmission means. If a higher input is input from the motor side while the brake is being operated by the mechanical transmission system, the one-way clutch allows rotation only in the input direction as shown in FIG. Can be directly transmitted to the reversible screw shaft. In the figure,
27 is a stop ring and 28 is a thrust bearing.

The operation of the electrically operated brake device having the above structure will be described. In the normal state (when the electric operating system is normal), the one-way clutch is in the released state as shown in FIG. Therefore, when the driver steps on the brake pedal, the pedaling force at this time is detected by the pedaling force sensor and is input to the electronic control unit. When the motor M is controlled and driven by a command from an electronic control unit (ECU), the rotation of the motor M changes from the output shaft from the motor to the reversible screw shaft 10
→ nut 13 → transmitted to the cone clutch 22 integrated with the nut. At this time, since the cone clutch 22 is connected to the slope 8a of the piston 8 and the nut 13 is non-rotating, the nut 13 does not rotate and is integrated with the piston 8 to resist the biasing force of the return spring 11a and to the left in the figure. Move to
The piston 8 is pushed to the left in the figure, and the disc pad 5 is pressed against the disc 6 to apply the brake. When the pressing force of the disk pad 5 on the disk 6 reaches a predetermined value, the pressing force sensor 20 detects this value and outputs it to the electronic control unit 3 to control the braking force by stopping the motor M or the like.

When the brake is released, the motor M is reversely operated by the pedaling force signal. Then, the reversible screw shaft 10 reversely rotates, and together with the urging force of the return spring 11a, the piston 8 and the nut 13 move to the right in the drawing to weaken the braking force. Further, when the reversible screw shaft 10 continues to rotate in the reverse direction, the reaction force of the disk pad 5 disappears, and when the return spring 11a returns to its original position, the piston 8 stops. At this time, when the motor or the like further rotates due to inertia, the cone clutch 22 and the sloped surface 8a of the piston 8 separate (clutch means is disengaged), so that the reversible screw shaft 10 and the nut 13 rotate integrally and the nut and Relative rotation with the reversible screw shaft is eliminated, and excessive return of the piston 8 can be prevented.

When the amount of depression of the brake pedal exceeds a predetermined value (for example, when the brake pedal is strongly depressed due to a failure in the electric system), the lever 18 is actuated via a mechanical transmission system (not shown). It rotates as shown in FIG. Then, as the lever 18 moves, the retainer 19 also rotates in the same direction, and the protrusion 19a moves to the end portion in the cam groove 15, so that the roller 16 is pressed against the cam groove 15 by the action of the spring 17 and the one-way clutch is opened. Connected. Thereafter, further rotation of the lever 18 is transmitted to the reversible threaded shaft 10 and the piston 8 can be moved to brake. It should be noted that, when a higher input is given from the motor side during the operation of the mechanical transmission system, the one-way clutch 14 allows the reversible screw shaft to rotate only in the input direction. Can be transmitted to the screw shaft.

In the above embodiment, the pedal force sensor may be provided anywhere, and the pressing force on the disk 6 by the disk pad 5 is detected from the load applied to the motor without using the pressing force sensor 20, The motor can also be controlled as described above. Also, various types of mechanisms can be adopted as the mechanism for transmitting the mechanical force to the lever. Further, the present invention is not limited to the above embodiment, and any mechanism can be applied as long as it has a similar function.

[0018]

As described in detail above, according to the present invention, a one-way clutch is incorporated in an electrically operated braking device, and when a failure or the like occurs in the electrically operated braking device, the one-way clutch is automatically operated through the clutch. The transmission path of the mechanical system is configured and the brake can operate. Further, when the inputs from the electrical system and the mechanical system are simultaneously activated, the operating force on the high input side is selectively transmitted to the brake device, so that the brake can be reliably activated under any circumstances. it can. Further, a clutch means is provided between the piston and a motor for driving the piston, and the clutch means can prevent the piston from returning too much due to overrun of the reverse rotation of the motor that occurs when the brake is loosened. It is possible to prevent excessive force from acting. As a result, the piston does not return too much due to the inertia of the motor rotational force when the brake is released, the gap between the disc pad and the disc can be always kept constant, and the responsiveness of brake control can be improved. In addition, the spring seat of the return spring has the function of an auto adjuster, so it is possible to accurately respond to wear of the disc pad. Further, since the braking force can be increased, maintained, or reduced by a control signal from the electronic control device, anti-skid control or traction control can be executed. It is possible to achieve excellent operational effects such as.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an electrically operated brake device as an embodiment according to the present invention.

FIG. 2 is an enlarged view of the AA cross section in FIG. 1, and is an explanatory view showing a non-operating state of the one-way clutch.

3A and 3B are a front view and a BB cross-sectional enlarged view of a retainer according to the present invention.

FIG. 4 is an enlarged view of a CC cross section in FIG.

FIG. 5 is an explanatory diagram showing a transition from the state shown in FIG. 2 to an operating state of a one-way clutch.

[Explanation of symbols]

 1 brake pedal 2 pedal force sensor 3 electronic control device 4 caliper 5 disc pad 6 disc 7 cylinder 8 piston 9 detent means 10 reversible screw shaft 11 recessed groove 11a return spring 12 elastic body 13 nut 14 one-way clutch 18 lever 19 retainer 20 pressing force Sensor 21 Detent 22 Cone clutch

Claims (2)

[Claims] 1. A cylinder 7 formed in a caliper 4 of a brake device, a slidable piston 8 arranged in the cylinder 7, and a reversible screw for reciprocating the piston 8 toward a disk 6. The reversible screw shaft 10 includes a shaft 10, a motor M that operates the reversible screw shaft 10, and an electronic control unit 3 that controls the motor. A lever is arranged on the outer peripheral surface of the reversible screw shaft 10 through a one-way clutch. A mechanical force transmission system capable of operating the lever is connected to the lever, and the one-way clutch fixes the lever and the reversible screw shaft only when the lever operates. Brake device. 2. A one-way clutch provided on the outer peripheral surface of the screw shaft 10 includes a cam groove 15 formed in a lever.
And a roller 16 disposed in the cam groove, and the roller 1
6 and a spring 17 for urging the roller 6 toward the end of the cam groove, and the roller is held in the clutch disengagement position by a retainer provided adjacent to the lever when the lever is in the non-actuated state. The electrically operated braking device according to claim 1, wherein holding by the retainer is sometimes released, and the one-way clutch operates.