JPH06300062A - Driving device having ultrasonic motor as driving source - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a drive device capable of moving a driven member even if the ultrasonic motor cannot rotate. [Structure] An ultrasonic motor 60 is provided in a device body 64 fixed to the caliper 32. A nut 84 is non-rotatably fitted to the rotor 78 of the ultrasonic motor 60, and a screw shaft 94 is screwed to the nut 84. The rotation of the screw shaft 94 with respect to the apparatus main body 64 is prevented by fitting the stopper plate 118 over the slit 114 and the notch 116. When the parking brake is actuated, a current is supplied to the ultrasonic motor 60, and the forward movement of the screw shaft 94 causes the piston 44 to press the inner pad 14 against the friction surface 12.
When the electric current cannot be supplied to the ultrasonic motor 60, the lid 112 is removed, the stopper plate 118 is removed, the screw shaft 94 is rotated, and the piston 44 is retracted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device using an ultrasonic motor as a drive source, and more particularly to a drive device for giving a linear motion to a driven member.

[0002]

2. Description of the Related Art A drive device of this type includes a device configured as follows. (A) an apparatus main body, (b) an ultrasonic motor supported by the apparatus main body, (c) a first screw member supported by the apparatus main body and rotated about one axis by the ultrasonic motor, (d) ) A second screw member screwed to the first screw member, and (e) a rotation preventing device for preventing rotation of the second screw member with respect to the device body. When the first screw member is rotated by the ultrasonic motor, the rotation of the second screw member with respect to the device body is blocked by the rotation preventing device. Therefore, at least one of the first screw member and the second screw member has an axial direction. That is, the driven member can be linearly moved.

A drive device using such an ultrasonic motor as a drive source can be applied to a vehicle brake device as described in, for example, Japanese Patent Laid-Open No. 63-266228. In a disc brake that suppresses wheel rotation by pressing a pair of brake pads against the friction surfaces on both sides of the disc rotor, the nut as the first screw member rotated by the ultrasonic motor is set by the device body fixed to the caliper. A screw as a second screw member that is rotatably and immovably supported in the axial direction and movably and immovably supported by the apparatus body is screwed into the nut. Therefore, when the nut is rotated by the ultrasonic motor, the screw linearly moves to advance the piston, and the brake pad is pressed against the friction surface of the disc rotor to suppress the rotation of the wheel.

[0004]

The ultrasonic motor applies ultrasonic vibrations to the stator to generate surface waves, and also rotates the rotor by the frictional force acting between the stator and the rotor. Therefore, the rotor is pressed against the stator by the biasing means so that a necessary frictional force is obtained between the two, and a constant frictional force is generated between the stator and the rotor even when no voltage is applied. ing. Therefore, unless a voltage is applied to the stator, the rotor does not rotate, and linear movement due to relative rotation between the first screw member and the second screw member cannot be generated. For example,
In the brake device described in the above publication, when the screw is advanced and the brake pad is pressed against the disc rotor, and the voltage cannot be applied to the motor while the brake is applied, the screw is moved to the brake pad. Cannot be moved in a direction away from the disc rotor, and the brake remains applied, and it is troublesome to remove the ultrasonic motor in order to release the action of the brake. In this way, if the ultrasonic motor does not rotate, linear movement cannot occur.
The same applies not only to a vehicle brake device but also to a device using a drive device having an ultrasonic motor as a drive source.
An object of the present invention is to provide a driving device that can generate linear movement even if the ultrasonic motor does not rotate.

[0005]

In order to solve the above-mentioned problems, the present invention provides: (a) a device body, (b) an ultrasonic motor, (c) a first screw member, (d) a second screw. A rotation preventing device of a driving device having an ultrasonic motor including a member and (e) a rotation preventing device as a drive source, which can release the rotation preventing state of the second screw member and is rotated by the second screw member. The main point is to provide an operation unit.

[0006]

With this configuration, the rotation blocking device releases the rotation blocking state of the second screw member with respect to the main body of the apparatus, and the second screw member is rotated by operating the rotation operating portion, so that the first screw member is rotated. Relative movement occurs with the second screw member. It is possible to cause linear movement without rotating the ultrasonic motor, and thereby, for example, in the brake device described in the above publication, the brake pad can be separated from the disc rotor to release the brake.

[0007]

As described above, according to the present invention, it is possible to obtain a driving device which can cause a linear movement without rotating an ultrasonic motor and can move a driven member.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a parking brake drive device will be described in detail below with reference to the drawings. In FIG. 1, reference numeral 10 denotes a disk rotor, which rotates integrally with the wheels. Both surfaces of the disk rotor 10 are friction surfaces 12, and an inner pad 14 and an outer pad 16 are arranged facing the friction surfaces 12. These pads 14 and 16 are respectively provided with a friction material 18
And a steel back plate 20 fixed to the back surface thereof.

A mounting bracket 26 is fixedly provided in the vicinity of the disc rotor 10 and receives the rotational torque of the disc rotor 10. Inner pad 14
And the outer pad 16 is a mounting bracket 26.
Is supported slidably in a direction parallel to the rotation center line of the disk rotor 10, and when a brake pedal (not shown) is depressed, the friction surface 12 of the disk rotor 10 is moved by the caliper 32 having the hydraulic cylinder 30. Is pressed by.

The caliper 32 includes a cylinder portion 34 provided to face the back surface of the inner pad 14 and a reaction portion 36 provided to face the back surface of the outer pad 16.
And a connecting portion 38 for connecting these over the outer periphery of the disk rotor 10, and by two slide pins (not shown) that are provided upright on the mounting bracket 26, they are parallel to the rotation center line of the disk rotor 10. It is supported so that it can move in any direction.

The cylinder portion 34 includes a disk rotor 10
Cylinder bore 4 opened in a direction orthogonal to the friction surface 12 of
2 is formed, and the piston 44 is attached to the cylinder bore 42.
Are sealed by a seal ring 46 and are fitted so as to be liquid-tight and slidable. The piston 44 has a bottomed cylindrical shape, and a bottomed hole 48 is fitted in a direction to open in the cylinder bore 42, and a hydraulic chamber 50 filled with brake fluid is provided in the cylinder bore 42. By supplying the brake fluid to the hydraulic chamber 50 from the port 52, the piston 44 is advanced to press the inner pad 14 against the friction surface 12 of the disc rotor 10, and the reaction portion 36 causes the reaction portion 36 to oppose the outer pad 16 by the reaction force. The friction surface 12 on the side is pressed. The hydraulic cylinder 30 is formed by the cylinder portion 34 and the piston 44. 5
4 is a rubber dust seal.

When the parking brake operation switch 58 (see FIG. 3) is operated, the piston 44 is also moved forward by a drive device 62 having an ultrasonic motor 60 as a drive source, so that the inner pad 14 and the outer pad 16 are friction surfaces. Press on 12. Device body 64 of drive device 62
The stepped cylindrical support member 66, the disc 68 and the stepped cylindrical cover 70 are fixed to each other.
In, the screw is engaged with the rear end of the cylinder portion 34 of the caliper 32 (the end opposite to the disc rotor 10), and moves integrally with the caliper 32.

The ultrasonic motor 60 is disposed in a space surrounded by the disk 68 and the large diameter cylindrical portion 72 of the cover 70. The ultrasonic motor 60 has a stator 74 fixed to the disc 68 and a rotor 78 pressed against the stator 74 by a disc spring 76.

The stator 74 is formed by fixing a disk-shaped piezoelectric ceramics 75 to an elastic body 73 fixed to a disk 68. When an AC voltage is applied to the piezoelectric ceramics 75, the piezoelectric ceramics 75 vibrates. At the same time, a traveling wave traveling in the circumferential direction is generated in the elastic body 73,
The rotor 78, which is pressed against, rotates in the direction opposite to the traveling wave. Since the rotor 78 is pressed against the stator 74 by the disc spring 76, a frictional force is generated between the rotor 78 and the stator 74 even when a voltage is not applied to the piezoelectric ceramics, and the rotor 78 cannot be rotated unless a voltage is applied. Can not.

Each of the stator 74 and the rotor 78 has a fitting hole 8 centered on the rotation center line of the rotor 78.
0, 82 are formed, and the nut 84 as the first screw member
Are fitted. The inner diameter of the fitting hole 80 is larger than the outer diameter of the nut 84, and the nut 84 is fitted in the fitting hole 80 with a gap left in the radial direction. The inner diameter of the fitting hole 82 is equal to the outer diameter of the nut 84, the nut 84 is fitted in the fitting hole 82, and a key 86 is provided between the nut 84 and the rotor 78. Relative rotation with respect to the rotor 78 is blocked. The nut 84 is supported by the disc 68 and the cover 70 via bearings 88, 90, 92 so as to be rotatable and immovable in the axial direction.

A screw shaft 94 as a second screw member is screwed into the nut 84. Screw shaft 9
An end portion of the No. 4 on the cylinder portion 34 side is projected from the nut 84 and a movable member 96 is attached. The tip of the movable member 96 is fitted to a slide 98 fitted in the cylinder 34 so as to be liquid-tight and slidable in the axial direction. The slide 98 is provided with a pressing member 102 via a gap adjusting device 100. They are mounted concentrically. Pressing member 1
02 is fitted in the bottomed hole 48 of the piston 44 and abuts the bottom surface of the bottomed hole 48 to push the piston 44. In the gap adjusting device 100, when the friction material 18 is worn and the retracted end position of the piston 44 is the inner pad 14,
It is configured so that the pressing member 102 follows the displacement when it shifts to the side, so that even if the friction material 18 wears, the moving distance of the screw shaft 94 does not change, but it is already known. Since the device is a separate device, its description is omitted.

The rear end of the screw shaft 94 is projected from the nut 84. The diameter of the projecting end portion 106 is smaller than the inner diameter of the small-diameter cylindrical portion 108 of the cover 70, and the projecting end portion 106 is fitted in the small-diameter cylindrical portion 108 with a gap left in the radial direction and the opening 110 of the small-diameter cylindrical portion 108. (See FIG. 2). This opening 110
Is closed by a lid 112 that is detachably fixed to the cover 70 with screws 111.

As shown in FIG. 2, the projecting end portion 106 of the screw shaft 94 is formed with two slits 114 that pass through the axis of the screw shaft 94 and are orthogonal to each other. On the other hand, a portion of the cover 70 facing the protruding end portion 106 of the screw shaft 94 extends in the axial direction, and the cover 7
Four notches 116 opening to the inner peripheral surface of 0 are formed at equal angular intervals. A stopper plate 118 is fitted into one of the two slits 114. The stopper plate 118 has a protruding end portion 106.
Is longer than the diameter of the slit and the width is smaller than the notch 116, and is fitted into the slit 114, and
Both ends in the longitudinal direction are respectively fitted into two notches 116 which are diametrically separated from each other among the four notches 116,
As a result, the rotation of the screw shaft 94 with respect to the cover 70 is blocked. The slit 114, the notch 116 and the stopper plate 118 constitute a rotation preventing device, and when the nut 84 is rotated by the ultrasonic motor 60, the screw shaft 94 is linearly moved in the axial direction to advance the piston 44. Then, the inner pad 14 and the outer pad 16 are pressed against the friction surface 12 of the disk rotor 10.

The ultrasonic motor 60 is controlled by the controller 130 shown in FIG. The control device 130 is supplied with the detection signal of the parking brake operation switch 58, and also detects the wheel speed sensor 132 for detecting the wheel rotation speed, the accelerator switch 134 for detecting the depression of the accelerator pedal, and the depression of the brake pedal. The brake switch 136 is turned on. Further, the control device 130 controls the ultrasonic motor 60 via the motor drive circuit 138.

Next, the operation will be described. When the brake pedal is depressed while the vehicle is running, the hydraulic pressure generated in the pressurizing chamber of the master cylinder is supplied to the hydraulic chamber 50, the piston 44 is advanced, and the inner pads 14 and 16 are pressed against the friction surface 12. The rotation of the wheels is suppressed.

When the parking brake operating switch 58 is operated to operate the parking brake during parking, electric current is supplied to the ultrasonic motor 60, the nut 84 is rotated, and the screw shaft 9 is rotated.
4 is moved to the inner pad 14, the outer pad 1
6 is pressed against the friction surface 12. At this time, the stopper plate 118 moves in the notch 116 to allow the screw shaft 94 to move forward. When the power is turned off, the voltage application to the ultrasonic motor 60 is cut off,
In the ultrasonic motor 60, the rotor 78 is pressed against the stator 74 by the disc spring 76, and even if the voltage is not applied, the rotor 78 cannot freely rotate with respect to the stator 74, and the screw shaft 9
4 is maintained in the forward end position and the parking brake is kept active.

For some reason while the parking brake is applied in this way, it becomes impossible to supply the electric current to the ultrasonic motor 60, for example, the light is left on and the battery goes up during parking. In this case, it is impossible to release the parking brake by rotating the ultrasonic motor 60 in the direction opposite to that when the parking brake is applied. In this case, the operator removes the lid 112 and slits the stopper plate 118 in the opening 110.
4 and notch 116. As a result, the screw shaft 94 becomes rotatable with respect to the apparatus main body 64, and the operator engages the tool with the slit 114 to rotate the screw shaft 94 in the direction in which the parking brake is released, and the piston 44 is retracted to perform parking. The brake can be released.

After the release, the stopper plate 118 is fitted into the slit 114 and the notch 116 again to prevent the screw shaft 94 from rotating with respect to the nut 84. Since the two slits 114 are provided and the four notches 116 are provided, the stopper plate 118 is provided in the slit 11.
4. When fitting into the notch 116, it is sufficient to fit either of the slits 114 and the notch 116, and the rotation angle of the screw shaft 94 for adjusting the phase is small, and the fitting can be done quickly.

A rotation prevention device prevents and allows rotation of the screw shaft 94 by attaching and detaching the stopper plate 118 to and from the slit 114 and the notch 116, and at the rear of the screw shaft 94 facing the opening 110 of the cover 70. By being provided on the end side,
The rotation blocking state of the rotation blocking device can be released, and the slit 11 of the small-diameter cylindrical portion 108 can be released.
Reference numeral 4 constitutes a rotation operation section.

When the wheel speed sensor 132 detects the wheel speed, the depression of the accelerator pedal 134 is detected, or the depression of the brake pedal is detected, the wheel speed sensor 132 and the accelerator pedal 13 are detected.
4. The action of the parking brake is automatically released based on the detection signal of the brake switch 136. Therefore, the vehicle does not travel while the parking brake is still applied, and the vehicle is not double-braked by the brake and the parking brake.

In the above-described embodiment, the release of the rotation blocking state of the rotation blocking device and the rotation operation of the screw shaft 94 are both performed from the opening 110 of the cover 70, but they are performed at different positions. You may want to be told. In this case, for example, as shown in FIG. 4, in the rotation preventing device, the fitting portion 145 provided at the tip of the screw member 144 screwed in the circumferential wall of the small-diameter cylindrical portion 142 of the cover 140 in the radial direction, Notch 15 formed in protruding end portion 148 protruding from nut 84 of screw shaft 146
It is configured by fitting to 0.

On the peripheral wall of the small-diameter cylindrical portion 142, a female screw hole 152 having a bottom is formed, which opens to the outer peripheral surface of the small-diameter cylindrical portion 142, and the notches 150 are opened to the outer peripheral surface and the end surface of the projecting end portion 148. Books are formed at equal angular intervals. The screw member 144 is screwed into the female screw hole 152 in the screw portion 154, and the fitting portion 145 is fitted in the notch 150. In addition, when the screw member 144 is screwed, the shoulder surface 156 is formed in the female screw hole 15
The fitting portion 145 is regulated by abutting on the bottom surface of 2.
Does not impose a radial force on the screw shaft 146 to impede movement.

When current is no longer supplied to the ultrasonic motor with the parking brake applied,
The screw member 144 is removed to allow the screw shaft 146 to rotate with respect to the cover 140 and the lid 158.
The hexagonal hole 16 provided in the projecting end portion 148 of the screw shaft 146 from the opening 160 of the small diameter cylindrical portion 142.
The tool is engaged with 2 and the screw shaft 146 is rotated to release the action of the parking brake. Hexagon socket 16
2 constitutes the rotation operation section. Since the plurality of notches 150 are provided, the engagement portion 145 of the screw member 144 is notched 1 after the action of the parking brake is released.
When fitting to 50, it suffices to fit to one of the notches 150, the rotation angle of the screw shaft 146 required for fitting is small, and fitting can be done quickly.

In the above embodiment, the nut 84, which is a female screw member, is the first screw member that is rotated by the ultrasonic motor 60, and the screw shaft 94, which is the male screw member, is the second screw member that does not rotate. But
Conversely, the male screw member may be rotated and the female screw member may be prevented from rotating.

Further, in the above embodiment, the screw shaft 94 which is the second screw member is moved in the axial direction, and the nut 84 which is the first screw member is not moved. The second screw member may move in the direction and the second screw member may not move, or both the first and second screw members may move in the axial direction.

Furthermore, the apparatus main body may be provided so as to move together with the moving screw member of the first and second screw members, or may be provided at a fixed position.

In each of the above embodiments, the slit 11
The plurality of notches 116 and 150 are provided, but this is not essential.

Further, the rotation operation of the second screw member is not limited to manual operation, and may be performed by an electric tool or the like.

Further, in the above embodiment, the nut 84, which is the first screw member, is engaged with the rotor 78 of the ultrasonic motor 60 so that the rotation is directly transmitted. The rotation may be indirectly transmitted.

Furthermore, the present invention can be applied to a drive device using an ultrasonic motor as a drive source, which is used in devices other than the parking brake.

In addition, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of drawings]

FIG. 1 is a front view (partial cross section) showing a disc brake including a drive device using an ultrasonic motor as a drive source according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a rotation prevention device and a rotation operation unit of the drive device.

FIG. 3 is a diagram schematically showing a control device for controlling the ultrasonic motor.

FIG. 4 is a front cross-sectional view showing a rotation preventing device and a rotation operating portion of a drive device having an ultrasonic motor as a drive source, which is another embodiment of the present invention.

[Explanation of symbols]

 60 Ultrasonic Motor 62 Drive Device 64 Device Main Body 84 Nut 94 Screw Shaft 114 Slit 116 Notch 118 Stopper Plate 144 Screw Member 146 Screw Shaft 150 Notch 162 Hexagonal Hole

Claims (1)

[Claims] 1. An apparatus main body, an ultrasonic motor supported by the apparatus main body, a first screw member supported by the apparatus main body and rotated about one axis by the ultrasonic motor, and a first screw thereof. In a drive device including a second screw member screwed to a member, and a rotation preventing device that prevents rotation of the second screw member with respect to the device body, the rotation preventing device is a rotation preventing state of the second screw member. And a rotation operating portion provided on the second screw member.