JPH0914308A - Braking device - Google Patents

Abstract

PURPOSE: To provide two independent and different braking systems in a single device, to provide a device itself with a hydraulic control function and to optionally control a braking force. CONSTITUTION: A braking device 10 is provided with not only a first braking system composed of a hydraulic pressing part 100 but also a second braking system composed of an ultrasonic motor 70 and a torque conversion mechanism part 42. A plunger 58 is moved back and forth from a hydraulic chamber 110 so as to change the capacity of the hydraulic chamber 110. Thus, by moving the plunger 58 so as to change the capacity of the hydraulic chamber 110 during the braking of the hydraulic pressing part 100, a hydraulic pressure, that is, a braking force is optionally controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device in which a friction material such as a brake pad or a brake shoe is pressed against a rotating member such as a disc rotor or a brake drum that rotates together with a wheel to generate a braking force.

[0002]

2. Description of the Related Art Among brake devices for vehicles, for example, a disc brake device has been proposed in which a brake pad is pressed by a driving force of an electric motor, and thereby a disc rotor is sandwiched and braked (for example, as an example). JP-A-63-266228).

In this type of disc brake device, an ultrasonic motor is attached to a caliper housing,
Further, a driving force converting mechanism composed of a ball screw is built in the caliper housing instead of the piston. In this disc brake device, when the brake is operated, the ball screw is moved by the drive of the ultrasonic motor to press the brake pad to generate a braking force, and an electric actuator using a wire wound motor as a drive source is used. Compared with the above, the ultrasonic motor itself has advantages such as small size and low power consumption.

However, such a conventional disc brake device has a drawback that the disc brake device itself does not operate at all when the supply of power is cut off and the operation of the ultrasonic motor as a drive source is stopped.

Therefore, in order to configure two different brake systems independent of each other in a single device while maintaining a reliable brake operation performance, a brake operation section by an electric motor as described above and a hydraulic brake operation are provided. It is conceivable to configure it together with the section. With such a configuration, either one of the mechanisms can normally be used, and the other can be used as an emergency.

However, if the brake actuating portion using the electric motor and the hydraulic brake actuating portion are simply used in combination, the braking force by the hydraulic brake actuating portion is based on the driver's operating force. It cannot be controlled below the braking force due to hydraulic pressure. In other words, since the brake device itself does not have a hydraulic pressure control function, if a brake force by hydraulic pressure is to be controlled, another new hydraulic pressure control device is inevitably required. Therefore, for example, there is a case where the depressurization (release of the braking force) operation of the ABS (anti-lock brake system) cannot be performed by the brake device itself.

[0007]

SUMMARY OF THE INVENTION In consideration of the above facts, the present invention makes it possible to configure two different braking systems independent of each other in a single device while maintaining reliable braking performance. It is an object of the present invention to obtain a brake device in which the device itself has a hydraulic pressure control function, whereby the braking force can be arbitrarily controlled.

[0008]

A brake device according to a first aspect of the present invention is a brake device in which a friction material is pressed against a rotating member that rotates together with a wheel to generate a braking force. And a piston provided to face the friction material, the fluid pressure pressing portion that is actuated by hydraulic pressure to press the friction material, and is immovable by an external input to the rotating portion. An electric motor, a nut to which the electric motor is connected, and a screw shaft that is combined with the nut by a ball screw and is provided to face the piston of the hydraulic pressure pressing portion. The force is converted into an axial movement force of the screw shaft, and the piston is pressed by the axial movement of the screw shaft and the cylinder It is characterized with a volume changeable torque converting mechanism portion of the liquid chamber by reciprocating the liquid chamber to be formed, further comprising a within.

A brake device according to a second aspect of the present invention is the brake device according to the first aspect, wherein the electric motor includes a rotor connected to the nut, and a stator fixed to the housing so as to face the rotor. And an urging member for pressing the rotor into pressure contact with the stator.

[0010]

In the brake device according to the first aspect of the present invention, when the hydraulic pressure is supplied by the brake operation, the hydraulic pressure pressing portion is actuated, the friction material is pressed by the piston and pressure-contacts the rotating member,
Braking force is generated. On the other hand, when the electric motor is actuated by the brake operation, the torque of the electric motor is converted into the axial moving force of the screw shaft by the torque converting mechanism, the screw shaft moves in the axial direction, and the piston is pressed, whereby the aforementioned In the same manner as the above, the friction material is pressed and a braking force is generated. As described above, not only the first brake system by the hydraulic pressure pressing portion including the cylinder and the piston but also the second brake system by the driving force of the electric motor can be configured in a single device.

Further, since the electric motor is in a stationary state by an external input to its rotating portion, the axial moving force of the screw shaft of the torque converting mechanism portion is temporarily input to the rotating portion of the electric motor as an external input via the nut. Even if it works, the electric motor does not move. In other words, rotation of the nut of the torque conversion mechanism is blocked when the electric motor is not operating,
The screw shaft is also prevented from moving in the axial direction. Therefore, the brake operating state can be maintained (the parking brake operating state) by stopping the electric motor while the piston (friction material) is being pressed while the vehicle is stopped, for example.

Further, during operation of the electric motor, the screw shaft of the torque conversion mechanism section moves back and forth to the liquid chamber formed in the cylinder of the hydraulic pressure pressing portion, and changes the volume of this liquid chamber. Therefore, when the electric motor is operated to move the screw shaft forwards and backwards into the liquid chamber during the operation of the hydraulic pressure pressing portion, the volume of the liquid chamber is increased or decreased, and the hydraulic pressure is increased or decreased. Therefore, for example, when the hydraulic pressure portion is actuated and the electric motor is actuated to move the screw shaft in the direction away from the piston, the volume of the fluid chamber formed in the cylinder is increased and the fluid pressure is reduced. As a result, the braking force can be reduced, and it becomes possible to configure an ABS (anti-lock braking system) by the device itself.

As described above, in the brake device according to the first aspect, not only the first brake system by the hydraulic pressure pressing portion but also the second brake system by the driving force of the electric motor are independently provided in a single device. By independently controlling the second brake system by the driving force of the electric motor, the hydraulic pressure of the hydraulic pressure portion can be arbitrarily controlled (that is, the device itself has a hydraulic pressure control function). It is possible to control the braking force arbitrarily. Therefore, by independently controlling the brake device arranged for each wheel, an ideal braking force can be generated (distributed) for each wheel, and the braking performance is significantly improved.

In the braking device according to the second aspect, when the ultrasonic motor is actuated by the braking operation, the rotational force of the rotor of the ultrasonic motor is converted into the axial moving force of the screw shaft by the torque conversion mechanism portion, and the screw shaft is moved. By moving in the axial direction and pressing the brake pad, a braking force is generated.

Further, in the ultrasonic motor, the rotor is restrained by the self-holding force in the inoperative state. Therefore, when the ultrasonic motor is inoperative, the nut of the torque converting mechanism is prevented from rotating, and the screw shaft is also prevented from moving in the axial direction. Therefore, the brake operating state is maintained (the parking brake operating state) by stopping the ultrasonic motor while the brake pad is being pressed while the vehicle is stopped, for example.
be able to.

As described above, in the brake device according to the second aspect, not only the first brake system by the hydraulic pressure pressing portion but also the second brake system by the driving force of the ultrasonic motor is configured in a single device. be able to. Further, since the rotor of the ultrasonic motor is directly connected to the nut of the torque conversion mechanism section that is composed of a ball screw and converts the rotational force into the linear movement force, the ultrasonic motor and the torque conversion mechanism section are integrated. The device becomes compact as a whole.

[0017]

1 is a sectional view of a brake device 10 according to an embodiment of the present invention.

In the brake device 10, the inner pad 14 and the outer pad 16 are attached to the caliper housing 12 via a mounting bracket (not shown). These inner pad 14 and outer pad 1
Reference numeral 6 is provided so as to face a disc rotor 18 that rotates together with the wheels. The inner pad 14 is located on the inner side of the vehicle and the outer pad 16 is located on the outer side of the vehicle so that the disc rotor 18 is sandwiched by both pads. It is located in. Further, the caliper housing 12 covers the inner pad 14 and the outer pad 16 from above, and the claw portion 20 receives an outward force from the outer pad 16.

On the side of the inner pad 14, a hydraulic pressure pressing portion 1 is provided.
00 is arranged. In the hydraulic pressing unit 100, the caliper housing 12 is provided with the cylinder 102,
Further, a piston 104 is arranged in the cylinder 102. The piston 104 is housed in the cylinder 102 and is in contact with the inner pad 14, so that the inner pad 14 can be pressed. A dust seal 24 is attached between the piston 104 and the cylinder 102 to ensure dustproofness.

A cover 34 is fixed to the caliper housing 12 by a bolt 36, and a housing 32 is integrally fixed to the cover 34.

A torque conversion mechanism portion 42 is provided inside the housing 32 and the cover 34. The torque conversion mechanism section 42 is configured by a nut 44 and a screw shaft 46, and the nut 44 and the screw shaft 46 are combined by a ball screw 48. A support hole 50 having a shape such as a square shape or a spline groove is formed in the axial center portion of the screw shaft 46. The support hole 50 corresponds to the support shaft 54 of the plate 52 fixed to the housing 32. The support shaft 54 is formed in a shape corresponding to the support hole 50 such as a square shape or a spline shaft, and is inserted into the support hole 50 so as to be relatively movable in the axial direction. For this reason,
The screw shaft 46 is prevented from rotating and can slide only in the axial direction.

A plunger 58 is connected to the tip of the screw shaft 46. Plunger 58
Airtightness is maintained by the pressure-resistant sealing material 108 which is located between the piston 104 of the hydraulic pressure pressing unit 100 and the screw shaft 46 and is opposed to the piston 104, and is interposed between the hydraulic chamber 110 of the cylinder 102 and the pressure chamber. Has been done. This plunger 58 is mounted on the screw shaft 4
The piston 104 can be pushed by being moved by 6 and at this time, the volume of the liquid chamber 110 can be changed by moving back and forth to the liquid chamber 110 of the cylinder 102. Further, the thrust force sensor is built in the plunger 58, and the lead wire 60 of the thrust force sensor is connected to the screw shaft 4
It is guided to the outside through the shaft center portion 6 and the plate 52. As a result, when the screw shaft 46 is moved in the axial direction, the plunger 58 moves and the piston 10 moves.
4 is pressed, and the pressing force at this time is detected.

The nut 44 combined with the screw shaft 46 by the ball screw 48 is supported by the bearing 34 on the cover 34 so as to be movable in the axial direction and rotatable in the circumferential direction. Therefore, when the nut 44 rotates, the rotational force is transmitted to the screw shaft 46 by the ball screw 48, and the screw shaft 46 is moved in the axial direction. The plate 5 from the position supported by the bearing 62 of the nut 44
A flange portion 64 is formed so as to project in the vicinity of the second side.

A supporting portion 66 is provided on the housing 32 facing one end surface (on the plate 52 side) of the nut 44 in the axial direction, and a thrust bearing 68 is arranged. As a result, the thrust load acting on the nut 44 is transmitted through the thrust bearing 68 to the housing 3
It is adapted to be transmitted to the second support portion 66.

On the other hand, the torque conversion mechanism 42 (nut 4
An ultrasonic motor 70 is provided around 4). The ultrasonic motor 70 is composed of a stator 72, a rotor 74, and a disc spring 76 as a biasing member.

The stator 72 is fixed to the mounting portion 78 of the housing 32. The rotor 74 is provided on the opposite side of the stator 72 from the support portion 66 of the housing 32, and is connected to the nut 44 via a key. As a result, the rotor 74 is configured to rotate together with the nut 44 and move relative to the nut 44 in the axial direction. A disc spring 76 is arranged laterally of the rotor 74 with a plate 84 interposed. The center end of the disc spring 76 is supported by the flange portion 64 of the nut 44 via a spacer 88 for adjusting the pressing force, and always presses the rotor 74 toward the stator 72. For this reason, the rotor 74 always applies the predetermined pressure to the stator 72.
Is pressed against.

In the brake device 10 having the above structure, the liquid chamber 110 of the cylinder 102 is connected to the brake master cylinder 102 via the brake hose 120.
Further, in the middle portion of the brake hose 120, the liquid chamber 110
A valve 122 that selectively switches between communication and cutoff between the brake master cylinder 102 and the brake master cylinder 102, and a pressure sensor 124 that detects the hydraulic pressure of the brake fluid supplied from the brake master cylinder 102 are arranged. The valve 122 and the pressure sensor 124 are used in the brake control circuit 12
6 is electrically connected. Further, in the brake control circuit 126, the above-mentioned ultrasonic motor 70, the thrust sensor built in the plunger 58, and the lock / lock of the wheels.
The slip sensor 128 is connected.

Next, the operation of this embodiment will be described. In the brake device 10 having the above configuration, the ultrasonic motor 70 is inoperative in the normal state where the brake operation is not performed,
Although the screw shaft 46, that is, the plunger 58 enters the liquid chamber 110 of the cylinder 102, it does not press the piston 104. Further, the hydraulic pressure pressing unit 100
Is inoperative and the liquid chamber 110 is not pressurized. Therefore, the inner pad 14 is in a non-pressed state, a gap is formed between the inner pad 14, the outer pad 16 and the disc rotor 18, and the disc rotor 18 is not restrained.

Here, the brake pedal 13 is set by the driver.
When the brake master cylinder 102 is operated by operating 0, the cylinder 102 is braked via the brake hose 120.
Brake fluid is supplied to the liquid chamber 110, and the liquid chamber 110 is pressurized. As a result, the piston 1 of the hydraulic pressure unit 100 is
04 is moved and the inner pad 14 is moved to the disc rotor 1
8 is pressed against each other to generate a frictional force therebetween, and the disc rotor 1
Braking torque acts on 8. Further, simultaneously with the movement of the piston 104, the caliper housing 12 itself is moved in a direction away from the disc rotor 18, and the claw portion 20 is moved in the direction of the disc rotor 18 so that the outer pad 16 is moved.
When the outer pad 16 is pressed against the disc rotor 18, a frictional force is generated between the two and the braking torque acts on the disc rotor 18.

In this case, when the piston 104 is actuated to press the inner pad 14, the hydraulic pressure of the liquid chamber 110 is detected by the pressure sensor 124, and a pressing force (braking force) corresponding to the brake operating force is obtained. As described above, the valve 122 is operated by the control of the brake control circuit 126 so that the liquid chamber 11
It is also possible to control the hydraulic pressure by selectively switching communication / interruption between 0 and the brake master cylinder 102.

On the other hand, when the brake pedal is operated and the brake is operated, the ultrasonic motor 70 is operated.
That is, the rotor 74 is rotated by the traveling wave generated in the stator 72 when a predetermined voltage is applied, and the nut 44 is rotated together with the rotor 74. This nut 4
The rotational force of No. 4 is transmitted to the screw shaft 46 by the ball screw 48, and the screw shaft 46 is moved in the axial direction. When the screw shaft 46 is moved in the axial direction, the inner pad 14 is pressed via the plunger 58, so that the inner pad 14 moves toward the disc rotor 1.
8 is pressed against each other to generate a frictional force therebetween, and the disc rotor 1
Braking torque acts on 8. Further, at the same time when the screw shaft 46 moves in the axial direction, the pawl portion 20 is moved in the same manner as described above.
Moves toward the disc rotor 18 and presses the outer pad 16, so that the outer pad 16 moves
When the disc rotor 18 is
Braking torque acts on.

In this case, when the ultrasonic motor 70 is actuated to move the screw shaft 46 in the axial direction and the plunger 58 presses the piston 104, this pressing force is applied by the thrust sensor built in the plunger 58. The drive of the ultrasonic motor 70 is controlled by the control of the brake control circuit 126 so that the detected pressing force (braking force) corresponds to the braking operation force. For controlling the drive (rotation speed, torque, etc.) of the ultrasonic motor 70, applied voltage, drive frequency, phase (phase difference between two or more applied voltages input to the stator 72 to generate traveling waves), etc. Is used.

As described above, in the brake device 10, the hydraulic pressure portion 100 including the cylinder 102 and the piston 104.
Ultrasonic motor 7 as well as the first brake system by
The second brake system with zero driving force can be independently configured in a single device. Therefore, for example, if the first brake system by the hydraulic pressure pressing unit 100 is used as the main system and the second brake system by the driving force of the ultrasonic motor 70 is used as the auxiliary system, the operating force for operating the brake pedal 130 (necessary). It is possible to reduce the pedaling force) and to eliminate or downsize the steering force assist device such as a master back.

Further, in this case, in the brake device 10, the rotor 74 of the ultrasonic motor 70 is restrained by the self-holding force in the inoperative state. Therefore, when the ultrasonic motor 70 is not operating, the nut 44 of the torque converting mechanism 42 is prevented from rotating, and the screw shaft 46 is also prevented from moving in the axial direction. Therefore, for example, when the vehicle is stopped, the ultrasonic motor 70 is stopped while the inner pad 14 and the outer pad 16 are kept in pressure contact with the disc rotor 18, so that the brake operating state is maintained (the parking brake operating state is set). )be able to.

Furthermore, in the brake device 10, the plunger 58 moved by the screw shaft 46 of the torque converting mechanism 42 when the ultrasonic motor 70 is operated.
Moves to and from the liquid chamber 110 formed in the cylinder 102 of the hydraulic pressure pressing unit 100, and changes the volume of the liquid chamber 110. Therefore, if the ultrasonic motor 70 is operated and the plunger 58 is moved back and forth to the liquid chamber 110 during the operation of the hydraulic pressure pressing portion 100 (first brake system), the liquid chamber 11
The zero volume is increased or decreased, resulting in increased or decreased hydraulic pressure.

Therefore, for example, when the ultrasonic motor 70 is actuated to move the plunger 58 in the direction away from the piston 104 when the hydraulic pressure portion 100 is actuated, it is formed in the cylinder 102 as shown in FIG. The volume of the liquid chamber 110 is increased, the liquid pressure can be reduced, and the braking force can be reduced, so that it becomes possible to configure an ABS (anti-lock brake system) by the device itself.

That is, for example, the brake pedal 130
When the wheel is locked or slips when the hydraulic pressure unit 100 is operated by operating the brake pressure sensor 100, this is detected by the lock / slip sensor 128, and the brake control circuit 12
6 reduces or eliminates the thrust force of the plunger 58 (assist force pressing the piston 104) due to the driving of the ultrasonic motor 70, thereby weakening the braking force. Further, when the wheel lock / slip state is still not resolved by the braking force reducing operation, the valve 122 is operated to disconnect the fluid chamber 110 from the brake master cylinder 102, and the ultrasonic motor is operated. 70 is further operated to move the plunger 58 in the direction away from the piston 104. This allows
The volume of the liquid chamber 110 formed in the cylinder 102 is increased, the hydraulic pressure is reduced, and the pressing force of the piston 104 is reduced, so that the wheel lock / slip state can be eliminated.

In this case, the operation of operating the ultrasonic motor 70 to move the plunger 58 with respect to the piston 104 to change the volume of the liquid chamber 110 and change the liquid pressure is performed.
It may be performed immediately (without waiting for the operation of weakening the braking force (assist force) by driving the ultrasonic motor 70) when the wheel is locked or slips.

As described above, in the brake device 10, not only the first brake system by the hydraulic pressure pressing portion 100 but also the second brake system by the driving force of the ultrasonic motor 70 are independently configured in a single device. Therefore, by independently controlling the second brake system by the driving force of the ultrasonic motor 70, the hydraulic pressure of the hydraulic pressure portion 100 (liquid chamber 110) can be arbitrarily controlled (that is, The device itself has a hydraulic pressure control function), which makes it possible to arbitrarily control the braking force. Therefore, by independently controlling the brake device 10 arranged for each wheel, an ideal braking force can be generated (distributed) for each wheel, and the braking performance is significantly improved.

Further, in the brake device 10 according to the present embodiment, the rotor 74 of the ultrasonic motor 70 is directly connected to the nut 44 of the torque converting mechanism 42 which is composed of the ball screw 48 and converts the rotational force into the linear moving force. , Ultrasonic motor 70
Since the torque conversion mechanism section 42 and the torque conversion mechanism section 42 are integrated, the apparatus becomes compact as a whole. Furthermore, since the rotational force is converted into the axial direction moving force by the ball screw 48, a large operating force is not required, and the parking brake operating state can be reliably achieved. Further, in the brake device 10, in order to convert the rotational force of the nut 44 of the torque conversion mechanism portion 42 into the axial direction moving force of the screw shaft 46, the screw shaft 46 is provided with the support hole 50, and the plate 52 is provided in the support hole 50. Insert the support shaft 54 of the screw shaft 46
Is prevented from rotating and is slidable only in the axial direction. That is, since a mechanism for preventing the rotation of the screw shaft 46 and allowing the screw shaft 46 to slide only in the axial direction is provided in the axial center portion of the screw shaft 46, no extra space is required and the overall size can be reduced.

Although the ultrasonic motor 70 is used as the electric motor in the present embodiment, the present invention is not limited to this, and other electric motors such as a DC motor may be used. In this case, it can be realized by providing a worm gear on the rotating shaft of the DC motor and providing a worm wheel meshing with the worm gear on the nut 44 of the torque conversion mechanism portion 42.

Further, in this embodiment, the thrust sensor for detecting the thrust of the plunger 58 (the pressing force of the piston 104) is built in the plunger 58, but the present invention is not limited to this, and the thrust sensor is not limited to the plan. The jar 58 may be provided separately and independently.

In this embodiment, the cylinder 10
The brake hose 120 connecting the second fluid chamber 110 and the brake master cylinder 102 is provided with a pressure sensor 124 to detect the fluid pressure of the brake fluid sent from the brake master cylinder 102 to detect the pressing force according to the brake operating force ( However, the present invention is not limited to this, and a sensor for directly detecting the operating force of the brake pedal 130 is provided, whereby the pressing force (braking force) according to the brake operating force is provided. The configuration may be such that the hydraulic pressure of the brake fluid is controlled so that

Further, in the above-mentioned embodiment, the present invention is a so-called pin slide type (piston floating type).
Although the example applied to the single-cylinder type disc brake device 10 has been described above, the present invention is not limited to this and can be applied to other types such as a drum brake.

[0045]

As described above, in the brake device according to the present invention, two different brake systems independent from each other can be configured in a single device while maintaining a reliable brake operation performance. The device itself has a hydraulic pressure control function, which has an excellent effect that the braking force can be arbitrarily controlled.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a brake device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a brake device according to an embodiment of the present invention and showing a state in which a volume of a brake fluid chamber is increased.

[Explanation of symbols]

 10 Brake Device 12 Caliper Housing 14 Inner Pad (Friction Material) 16 Outer Pad (Friction Material) 18 Disc Rotor (Rotating Member) 42 Torque Conversion Mechanism Section 44 Nut 46 Screw Shaft 48 Ball Screw 58 Plunger 70 Ultrasonic Motor (Electric Motor) 72 stator 74 rotor 100 hydraulic pressure pressing unit 102 cylinder 104 piston

Claims (2)

[Claims] 1. A brake device in which a friction member is pressed against a rotating member that rotates together with a wheel to generate a braking force, a cylinder, and a piston housed in the cylinder and provided opposite to the friction member. And a hydraulic pressing portion that is actuated by hydraulic pressure to press the friction member, an electric motor that is immobile with external input to the rotating portion, and a nut to which the electric motor is connected, A screw shaft which is assembled to the nut by a ball screw and is provided so as to face the piston of the hydraulic pressure portion, and converts the rotational force of the electric motor into an axial movement force of the screw shaft, and the screw shaft It is possible to change the volume of the liquid chamber by pressing the piston and moving it back and forth into the liquid chamber formed in the cylinder by moving the piston in the axial direction. And a torque conversion mechanism section. 2. The ultrasonic motor comprising: an electric motor; a rotor connected to the nut; a stator fixed to the housing so as to face the rotor; and an urging member for pressing the rotor into pressure contact with the stator. The brake device according to claim 1, wherein