JPH11101282A - Motor-driven brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten an energizing time to an electric motor and reduce the size of the motor by a method wherein torque exceeding rated torque is generated by the electric motor and with a press force by a friction pad sufficiently increased, the press force is held. SOLUTION: In this device, a reduction gear 18 and a rotation control device 19 are arranged between a screw rod 15 to convert rotation of an electric motor 12 into the axial direction of a piston 14 and the motor shaft 12A of the electric motor 12. When the piston 14 is driven in the increase direction of a press force output torque of the electric motor 12 is momentarily increased to a value higher than rated torque, and the rotation of the electric motor 12 is transmitted in high torque to the screw rod 15 through the rotation control device 19 and the reduction gear 18. Further, in a state that the press force of the piston 14 is sufficiently increased, rotation of the electric motor 12 is stopped and the press force of the piston 14 is held by the rotation control device 19, and each friction pad 25 is kept to be strongly pressed against the disc 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric brake device suitably used for applying a braking force to, for example, a vehicle or the like.

[0002]

2. Description of the Related Art In general, an electric motor is provided in a brake housing, and a rotational output (torque) of the electric motor is converted into a pressing force in an axial direction. An electric brake device configured to apply a braking force to a rotating member is known, for example, from Japanese Patent Application Laid-Open No. 4-108058.

[0003] An electric brake device of this kind according to the prior art is provided with a brake housing, a reduction gear provided in the brake housing together with an electric motor, for reducing the rotation of the electric motor, an output shaft of the reduction gear and a piston. And a feed screw mechanism that converts the rotation of the output shaft into an axial displacement of the piston, and a friction pad that is pressed toward the disk by the piston and applies a braking force to the disk. ing.

In a conventional electric brake device, when a driver of a vehicle depresses a brake pedal, the electric motor is rotated at a rotation angle or rotation speed corresponding to the operation amount at this time. The rotation of the electric motor is converted into the axial displacement of the piston by the feed screw mechanism, and the friction pad is pressed toward the surface of the disk by the piston to apply a braking force to the vehicle via the disk. Has become.

The speed reducer comprises a worm gear type reduction gear mechanism or the like, and reduces the high speed rotation of the electric motor to transmit a low speed, high torque rotational force (driving force) to the feed screw mechanism side. The rotational force is transmitted in one direction from the electric motor side to the feed screw mechanism side, and is configured as an irreversible mechanism that regulates transmission of rotational force from the feed screw mechanism side to the electric motor.

[0006]

In the prior art described above, the speed reducer provided between the electric motor and the feed screw mechanism is constituted by an irreversible mechanism composed of a worm gear or the like. The piston of the feed screw mechanism is driven by the torque of the motor in the increasing direction of the pressing force, and the rotation of the electric motor is stopped in a state where the pressing force (brake reaction force) of the friction pad against the disk of the vehicle is sufficiently increased. Also, there is an advantage that the pressing force against the disk can be secured by the holding force of the worm gear, and power can be saved.

However, worm gears generally have poor mechanical efficiency, and in order to sufficiently increase the pressing force, it is necessary to increase the size of the electric motor and increase the amount of current such as applied voltage. Not only can the power be reduced, but also the overall device cannot be reduced in size and weight.

In general, the electric motor can be continuously used only at the rated torque or less, and as long as the electric motor is operated within the range of the rated torque or less, the size of the electric motor must be increased to increase the pressing force. There is a problem that does not get.

The present invention has been made in view of the above-mentioned problems of the prior art. For example, a torque greater than a rated torque is generated in an electric motor, and the pressing force by a friction member such as a friction pad is sufficiently increased. It is an object of the present invention to provide an electric brake device capable of maintaining a pressing force, reliably reducing the time for energizing an electric motor, and reducing the size of the motor.

[0010]

According to the present invention, there is provided a brake housing, an electric motor provided in the brake housing, and an axial pressing force generated by rotation of the electric motor. The present invention is applied to an electric brake device comprising a pressing force generating means and a friction member which is pressed toward the rotating member by the pressing force generating means and applies a braking force to the rotating member.

A feature of the construction adopted by the invention of claim 1 is that the pressing force generating means converts the rotation of the electric motor into axial displacement of a piston, and the piston turns the friction member into a rotating member. A feed screw mechanism that presses the electric motor and a pusher that holds the pressing force when the torque of the electric motor expires while driving the piston of the feed screw mechanism in the direction of increasing the pressing force by the torque of the electric motor. The pressure holding mechanism and the pressing force by the pressing force holding mechanism are released when the electric motor rotates in the reverse direction, and the torque of the electric motor drives the piston of the feed screw mechanism in the direction of decreasing the pressing force. And an allowable pressing force release mechanism.

That is, in general, unless the electric motor is used continuously, a torque about three times the rated torque can be output. Therefore, when driving the piston of the feed screw mechanism in the direction of increasing the pressing force, for example, the torque of the electric motor is instantaneously increased to a torque value equal to or higher than the rated torque, and the pressing force of the piston is sufficiently increased. To stop (revoke) the rotation of the electric motor. In this state, the pressing force can be held by operating the pressing force holding mechanism, and the friction member can be kept pressed strongly against the rotating member by the piston.

On the other hand, when the electric motor is rotated in the reverse direction to release the braking force when the brake operation is stopped, the pressing force release mechanism operates to release the pressing force by the pressing force holding mechanism, and the reverse of the electric motor can be released. It is possible to allow the piston of the feed screw mechanism to be driven in the direction of decreasing the pressing force by the torque due to the rotation, whereby the friction member can be retracted so as to be quickly separated from the rotation member.

According to the second aspect of the present invention, the pressing force holding mechanism includes a first rotating body that rotates integrally with the electric motor, and a relative rotation between the first rotating body and the brake housing. And a second rotating body connected to the rotating part of the feed screw mechanism and provided between the first and second rotating bodies located in the brake housing. When the torque of the electric motor expires, the second rotating body is restrained by the brake housing and the rotation in the reverse direction is restricted when the torque of the electric motor expires. And a rotation transmitting / restricting portion.

Thus, when the electric motor is rotated in one direction and the piston of the feed screw mechanism is driven in the direction of increasing the pressing force, the rotation of the first rotating body is rotated by the second through the rotation transmitting / regulating section. The pressing force of the piston can be sufficiently increased by transmitting the torque to the rotating body and instantaneously increasing the torque of the electric motor to a torque value equal to or higher than the rated torque. Then, when the rotation of the electric motor is stopped (revoked) in this state, the second rotating body can be restrained to the brake housing side by the rotation transmitting / regulating section, and the second rotating body is moved in the reverse direction (reduction of the pressing force). Direction). Thus, the pressing force holding mechanism can be operated to hold the pressing force, so that the piston can continue to strongly press the friction member against the rotating member.

Furthermore, according to the third aspect of the present invention, the rotation transmission
The regulating unit rotates the second rotating body in one direction together with the first rotating body until the torque of the electric motor reaches the rated torque, and when the torque exceeds the rated torque, the first rotating body rotates in the second direction. When the torque of the electric motor expires in this state, the second rotating body is restrained on the brake housing side to rotate in the opposite direction. Is regulated.

Thus, when the torque of the electric motor is instantaneously increased to a torque value equal to or higher than the rated torque, the rotation transmission / restriction unit determines that the first rotating body is predetermined with respect to the second rotating body. Relative rotation only by the angle of rotation, and when the rotation of the electric motor is stopped (revoked) in this state, the second rotating body is restrained to the brake housing side,
The rotation of the second rotating body in the opposite direction (the direction in which the pressing force decreases) can be restricted.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electric brake device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1 to 6 show a case where the electric brake device according to the first embodiment of the present invention is applied to a floating caliper type disk brake.

In FIG. 1, reference numeral 1 denotes a carrier provided on a non-rotating portion of the vehicle. The carrier 1 is fixed to, for example, an inner side of the vehicle via a bolt or the like, and a pair of arms 1A, 1A extending toward the outer side. have. Each arm 1A of the carrier 1 straddles the outer peripheral side of the disk 2 as a rotating member that rotates integrally with a vehicle wheel (not shown),
Each of the friction pads 25 described below is slidably supported on both axial sides of the disk 2.

A guide hole (not shown) having a bottom extending in the axial direction of the disk 2 is formed in each of the arms 1A to support a caliper 4 to be described later displaceably with respect to the carrier 1. A pair of sliding pins (not shown) are slidably inserted into the respective guide holes. Further, a connecting portion 1B is integrally formed on the distal end side of each arm portion 1A, and the connecting portion 1B connects the respective arm portions 1A on the outer side of the disk 2 to increase the rigidity of the entire carrier 1. is there.

Reference numerals 3 and 3 denote protective boots inserted into the outer peripheral sides of the respective sliding pins, and 4 denotes calipers constituting a brake housing attached to the respective arm portions 1A of the carrier 1 via the respective sliding pins. As shown in FIG. 2, the caliper 4 is located on one side (inner side) of the disk 2, and is located on the inner leg 5 having a piston sliding hole 5 </ b> A and the like on the other side (outer side) of the disk 2. 1 and a bridge 7 for connecting the inner leg 5 to the outer claw 6 across the outer peripheral side of the disk 2, and the periphery of the disk 2 from both sides of the inner leg 5 as shown in FIG. And a pair of mounting portions 9, 9 each of which protrudes in the direction, and each of the sliding pins is fixed by bolts 8, 8.

Here, a receiving hole 5B having a larger diameter than the piston sliding hole 5A is formed in the inner leg portion 5 at a position behind the piston sliding hole 5A. A stepped cylindrical case (motor housing) 10 constituting a part of the brake housing is positioned in a detented state. The cylindrical case 10 accommodates an electric motor 12 and a speed reducer 18 to be described later, and the inner peripheral surface of the cylindrical case 10 has a sliding surface 10
A.

Reference numeral 11 denotes a piston sliding hole 5A of the inner leg portion 5.
The lid 11 is a lid having the housing hole 5B removably closed at a position opposite to the lid. The lid 11 constitutes a brake housing together with the caliper 4 and the cylindrical case 10, and the cylindrical case 10 is disposed inside the inner leg 5. In addition to positioning in the axial direction, the electric motor 12 and the like are positioned in the cylindrical case 10.

Reference numeral 12 denotes an electric motor housed in the cylindrical case 10 of the inner leg portion 5, and the electric motor 12 is rotated by a power supplied from an external control unit (not shown) to rotate the motor shaft 12A. When driven, the piston 14 described later is slid in the axial direction. That is,
When the driver of the vehicle depresses a brake pedal (not shown), a signal corresponding to the operation amount at this time is output to the control unit, and the control unit uses a rotation angle or rotation speed corresponding to the operation amount. A control signal is output so as to rotate the electric motor 12, and power is supplied.

Reference numeral 13 denotes the inner leg 5 together with the electric motor 12.
The pressing force generating device 13 includes a piston 14, a screw rod 15, which will be described later, a speed reducer 18, a rotation control device 19, and the like. During rotation, the piston 14 moves forward or backward in the axial direction.

14 is a piston sliding hole 5A of the inner leg 5
A piston slidably provided in the piston 14
Constitutes a feed screw mechanism together with the screw rod 15, and has a screw hole 14 </ b> A screwed to the screw rod 15 on the inner peripheral side. Then, the piston 14 is driven by the electric motor 12 through the screw rod 15 and the friction pad 25 is
To slide in the axial direction in the piston sliding hole 5A. Further, for example, a detent or the like for restricting rotation of the piston 14 around the screw rod 15 is provided between the front end side of the piston 14 and a friction pad 25 on the inner side described later.

Reference numeral 15 denotes a threaded rod constituting a rotating part of the feed screw mechanism. The threaded rod 15 has a thread formed on the outer peripheral side, and is screwed into a threaded hole 14A of the piston 14. The screw rod 15 is configured to convert the rotation of the electric motor 12 into the axial displacement of the piston 14 by transmitting the rotation of the electric motor 12 via the speed reducer 18 and the like.

A reduction gear 18 is provided at the base end of the screw rod 15.
The rotary plate 16 constituting the output shaft is integrally provided, and the outer peripheral side of the rotary plate 16 is rotatably supported on the front end surface of the cylindrical case 10 via a thrust bearing 17. The thrust bearing 17 receives a later-described brake reaction force or the like via the cylindrical case 10 to prevent a thrust load from acting on the speed reducer 18 and the like.

Reference numeral 18 denotes a speed reducer located between the rotary plate 16 and the electric motor 12 and disposed in the cylindrical case 10. The speed reducer 18 has an input shaft 18A integrated with a rotary plate 21 described later. The rotation of the input shaft 18A is reduced and transmitted to the output side rotating plate 16. The speed reducer 18 controls the rotation of the electric motor 12 by a rotation control device 19 described later.
When the rotation is transmitted to the input shaft 18A via the motor, the rotation is output to the rotating plate 16 with a constant reduction ratio, so that a large torque is generated in the screw rod 15 and the rotational load of the electric motor 12 is reduced. It has a function to make it work.

Numeral 19 designates a motor shaft 12A of the electric motor 12 and an input shaft 18A of the speed reducer 18 which are located in the cylindrical case 10.
Between the rotation control device 1 and the rotation control device 1
Reference numeral 9 denotes rotating plates 20, 21, a lever 22, and a ball 2 to be described later.
4 and the like, and is configured to serve both as a pressing force holding mechanism and a pressing force releasing mechanism.

Reference numeral 20 denotes a rotating plate which is provided on the tip end side of the motor shaft 12A and constitutes a first rotating body.
Is formed as a disk having a certain thickness, and rotates integrally with the motor shaft 12A of the electric motor 12. The rotating plate 20 is driven to rotate in the direction of arrow A in FIG. 3 by the electric motor 12 when the brake is operated, and is driven to rotate in the direction of arrow B when the brake operation is released. As shown in FIGS. 3 to 5, a stopper projection 20A protruding radially outward into a concave groove 21B described later on the outer peripheral side of the rotating plate 20, and a predetermined angle in the circumferential direction from the stopper projection 20A. A cam surface 20B formed as a flat surface on the outer peripheral surface of the rotary plate 20 is provided at a position separated by a distance.

Reference numeral 21 denotes another rotary plate which constitutes a second rotary member rotatably provided between the sliding surface 10A of the cylindrical case 10 and the rotary plate 20. Is formed as a thicker disk having a diameter larger than that of the rotary plate 20 and is provided integrally with the input shaft 18A of the speed reducer 18. The rotary plate 21 has a circular recess 21A having a hole diameter corresponding to the outer diameter of the rotary plate 20, as shown in FIG.
Are formed, and the rotating plate 20 is accommodated in the recess 21A.

The rotary plate 21 is formed with a groove 21B which is located on the outer peripheral side of the recess 21A and in which the stopper projection 20A of the rotary plate 20 is inserted. At a constant angle θ. The concave groove 21B allows the rotary plates 20, 21 to rotate relative to each other by the angle θ, and further rotates the rotary plates 20, 21 relative to the stopper projection 20A.
It is configured to be regulated via. Furthermore, the rotating plate 2
1, a lever housing hole 21C is formed at a position substantially corresponding to the cam surface 20B of the rotary plate 20 and is spaced apart from the concave groove 21B in the circumferential direction.
And the outer peripheral surface of the rotating plate 21.

Reference numeral 22 denotes a lever that is swingably disposed in the lever accommodating hole 21C. The lever 22 has a base end side connected to the rotary plate 21 via a pin 23 at one side of the lever accommodating hole 21C. The distal end side is a free end extending to the other side of the lever accommodation hole 21C. And the lever 22 is the ball 2
4 together with a rotation transmitting / restricting portion, which is displaced up and down between the standby position shown in FIG. 3 and the lift position shown in FIGS. 4 and 5 by the cam surface 20B of the rotating plate 20. It is.

Numeral 24 denotes a ball accommodated in the lever accommodating hole 21C of the rotating plate 21 together with the lever 22.
Is made of a steel ball or the like having high rigidity.
Are in a free state in the lever accommodating hole 21C while in the standby position shown in FIG. When the rotating plates 20 and 21 are forcibly rotated by the angle α in the direction indicated by the arrow B when the lever 22 is at the lift position shown in FIG.
As shown in the figure, the sliding surface 10A of the cylindrical case 10 and the lever 2
2 to restrain the rotating plate 21 against the sliding surface 10 </ b> A of the cylindrical case 10. Thereby, the rotating plate 2
Reference numeral 1 indicates that further rotation in the direction of arrow B is restricted, and the pressing force is held together with the lever 22 and the ball 24 during the brake operation.

In this state, when the electric motor 12 is rotated in the reverse direction to release the brake operation and the rotary plate 20 is driven to rotate in the direction indicated by the arrow B, the rotary plate 20 has an angle θ with respect to the rotary plate 21. After the relative rotation by the distance, the stopper projection 20A engages with the concave groove 21B as shown in FIG. 3, and the lever 22 is displaced from the lift position in FIG. 5 to the standby position in FIG. As a result, the restrained state of the rotary plate 21 with respect to the cylindrical case 10 is automatically released, the pressing force is released, and the rotary plates 20 and 21 rotate freely inside the cylindrical case 10 integrally. become able to.

Reference numerals 25, 25 denote friction pads serving as a pair of friction members disposed on both sides of the disk 2. Of the friction pads 25, the inner friction pad 25 is the piston 1
4 presses the disk 2 toward one side surface. Further, the outer friction pad 25 is displaced by the pressing reaction force at this time in such a manner that the entire caliper 4 slides and displaces in the axial direction with respect to the carrier 1 shown in FIG. Pressed toward the other side. Each friction pad 25 applies a braking force to the rotating disk 2 by strongly clamping the disk 2 from both sides.

Further, the electric motor 12 generally has a torque characteristic such as a characteristic line 26 shown by a solid line in FIG. 6, and its output torque T decreases as the rotation speed N increases. When the electric motor 12 is used continuously,
The output torque T is limited to a region equal to or lower than the rated torque Tn indicated by a dotted line 27 in FIG. 6, and when the electric motor 12 is operated in a region equal to or higher than the rated torque Tn, it is limited to a short-time instantaneous use. It is something that will be.

The disk brake according to the present embodiment has the above-described configuration, and its operation will be described next.

First, before the brake operation is performed,
The rotating plates 20 and 21 of the rotation control device 19 provided between the electric motor 12 and the speed reducer 18 are in the state shown in FIG. 3, and the lever 22 is not lifted by the cam surface 20B of the rotating plate 20. It is in the standby position shown in FIG. The ball 24 is arranged in a free state in the lever accommodation hole 21C.

Next, when the driver of the vehicle depresses the brake pedal, a signal corresponding to the depressing operation amount of the brake pedal is transmitted to the control unit by a pedal sensor (not shown) provided near the brake pedal. Is output to Then, the control unit outputs a control signal corresponding to the operation amount to the electric motor 12, and drives the motor shaft 12A of the electric motor 12 to rotate at a rotation angle or rotation speed corresponding to the operation amount.

As a result, the rotation control device 19
0 is integrally rotated with the motor shaft 12A in the direction indicated by the arrow A, and after the rotary plate 20 is rotated relative to the rotary plate 21 by the angle θ, the stopper projection 20A is engaged with the concave groove 21B as shown in FIG. At the same time, the lever 22 is displaced from the standby position in FIG. 3 to the lift position in FIG. Then, in the state of FIG. 4, the rotation of the rotary plate 20 (in the direction of arrow A) is transmitted to the rotary plate 21, whereby the input shaft 18 </ b> A of the speed reducer 18 is rotated integrally with the rotary plate 21, and the screw rod 15 is decelerated. The rotation reduced by the machine 18 is transmitted.

Here, the rotational load acting on the electric motor 12 is small until the friction pad 25 on the inner side comes into contact with the disk 2 during the braking operation, and the electric motor 12 is sufficiently larger than the rated torque Tn shown in FIG. Is rotationally driven with a small output torque T.
2 can be rotated at a higher speed than the rated rotation speed Nn (continuous use area below the dotted line 27 shown in FIG. 6). Then, the high-speed rotation of the electric motor 12 is reduced by the speed reducer 18 and transmitted to the threaded rod 15 so that the piston 1
4 allows the inner friction pad 25 to quickly advance to the braking position where it comes into contact with the disk 2 by the pad clearance C shown in FIG.

When the inner friction pad 25 comes into contact with the disk 2, the rotational load of the electric motor 12 increases due to the brake reaction force at this time, and the electric motor 12
For example, a torque greater than the rated torque Tn acts on the motor shaft 12A. However, as long as the electric motor 12 is not used continuously, a torque higher than the rated torque Tn can be output as indicated by a characteristic line 26 shown in FIG.

Therefore, in the present embodiment, when driving the piston 14 toward the disk 2 in the direction of increasing the pressing force, the output torque T of the electric motor 12 is instantaneously increased to the rated torque Tn or more. By increasing the torque to the torque value and transmitting the rotation of the electric motor 12 to the screw rod 15 with a high torque via the rotation control device 19 and the speed reducer 18, the pressing force of the piston 14 is increased, and each friction pad 25 is disc-shaped. 2 is pressed strongly.

When the pressing force of the piston 14 is sufficiently increased, the rotation of the electric motor 12 is stopped (revoked), so that the time for energizing the electric motor 12 is positively reduced. When the rotational force of the electric motor 12 expires, a reverse rotational force acts on the screw rod 15 due to a brake reaction force acting from the disk 2 toward the piston 14, and the rotational force is increased. Is transmitted to the rotating plate 21 of the rotation control device 19 via the speed reducer 18.

As a result, a rotational force in the direction of arrow B shown in FIG.
1 is forcibly rotated together with the rotating plate 20 in the direction of arrow B by an angle α. During this time, since the lever 22 is held at the lift position as shown in FIGS.
Can be clamped between the sliding surface 10A of the cylindrical case 10 and the lever 22 as shown in FIG.
0 can be restricted to the sliding surface 10A.

As a result, the rotation of the rotating plates 20 and 21 in the direction of arrow B beyond the angle α can be restricted.
The pressing force of the piston 14 during the braking operation can be ensured, and the friction pads 25 can be continuously pressed strongly against the disc 2 by the piston 14. For example, a braking force can be reliably applied to a vehicle in the middle of travel through the disc 2. it can.

Next, when the depression operation of the brake pedal is released in this state, the electric motor 12 is rotated in the reverse direction by the signal from the pedal sensor. When the rotary plate 20 is driven to rotate in the direction indicated by the arrow B in FIG. 5 by the reverse rotation of the electric motor 12, after the rotary plate 20 rotates relative to the rotary plate 21 by an angle θ as shown in FIG. While the stopper projection 20A engages with the concave groove 21B, the lever 22 is displaced from the lift position in FIG. 5 to the standby position in FIG.

Thus, the restrained state of the rotary plate 21 with respect to the cylindrical case 10 is automatically released, the pressing force is released, and the rotary plates 20 and 21 are integrally moved inside the cylindrical case 10. You will be able to rotate freely. For this reason, the reverse rotation of the electric motor 12 is transmitted to the screw rod 15 via the rotating plates 20 and 21 and the speed reducer 18, and the piston 1
4 can be driven together with the friction pad 25 in a direction of retreating from the disk 2 (a direction in which the pressing force decreases), the pressing force of the friction pad 25 on the disk 2 can be reliably reduced, and the friction pad 25 can be moved from the disk 2. It can be quickly retracted and separated from the disk 2 by the pad clearance C.

Thus, according to the present embodiment, the speed reducer 18 and the rotation control are provided between the screw shaft 15 for converting the rotation of the electric motor 12 into the axial displacement of the piston 14 and the motor shaft 12A of the electric motor 12. When the piston 19 is driven toward the disk 2 in the increasing direction of the pressing force, the output torque T of the electric motor 12 is instantaneously increased to a torque value exceeding the rated torque Tn, for example.
The rotation of the electric motor 12 is controlled by the rotation control device 19 and the speed reducer 1
By transmitting with high torque to the threaded rod 15 via 8
The pressing force of the piston 14 is increased, and each friction pad 25 is pressed strongly against the disk 2.

When the pressing force of the piston 14 is sufficiently increased, the rotation of the electric motor 12 is stopped and the rotation control device 19 is operated to maintain the pressing force of the piston 14 during the brake operation. Along with
Each of the friction pads 25 can be kept pressed strongly against the disc 2 by the piston 14, and, for example, a braking force can be reliably applied to a running vehicle via the disc 2.

Therefore, according to the present embodiment, the electric motor 12 can be driven to rotate with the output torque T equal to or higher than the rated torque Tn during the brake operation of the vehicle, and the electric motor 12 can be driven in a state where the pressing force by the friction pad 25 is sufficiently increased. Even when the motor 12 is stopped, a high pressing force can be maintained by the rotation control device 19, and the time for energizing the electric motor 12 can be reliably reduced.

Further, as compared with the prior art using an irreversible mechanism such as a worm gear, the mechanical efficiency at the time of torque transmission and the like can be greatly improved, and the size of the electric motor 12 can be reduced to reduce the weight of the entire apparatus. Can also be achieved.

Further, when the friction pad 25 is moved by the pad clearance C between the time of the brake operation and the time of the brake release, the electric motor 12 can be rotated with the output torque T equal to or less than the rated torque Tn.
The electric motor 12 at a speed higher than the rated speed Nn shown in FIG.
Can be rotated at high speed, and the friction pad 25 (piston 14) can be quickly moved by the pad clearance C. As a result, the responsiveness of the brake operation can be improved, and the friction pad 25 can be returned early even when the brake operation is released, so that the responsiveness can be improved and the operability and safety can be greatly improved.

Next, FIGS. 7 to 10 show a second embodiment of the present invention. The feature of this embodiment is that the first and second motors are driven until the output torque of the electric motor reaches the rated torque. Another object of the present invention is to provide a configuration in which relative rotation between rotating bodies is restricted, brake control performance is improved at low torque, and a function of holding a pressing force by a piston is stabilized. Note that, in the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the figure, reference numeral 31 denotes a rotation control device employed in the present embodiment. The rotation control device 31 is, similarly to the rotation control device 19 described in the first embodiment, a cylindrical type shown in FIG. The motor shaft 12 of the electric motor 12 is located in the case 10.
A is disposed between A and the input shaft 18A of the speed reducer 18, and is configured to serve both as a pressing force holding mechanism and a pressing force releasing mechanism. However, the rotation control device 31 includes rotating plates 32 and 33, a lever 34, a spring 36, and a ball 3 which will be described later.
7, 38, etc.

Reference numeral 32 denotes a rotating plate constituting a first rotating body.
The rotating plate 32 is the rotating plate 2 described in the first embodiment.
0 and the motor shaft 1 of the electric motor 12
It rotates together with 2A. The rotating plate 32 is driven to rotate in the direction of arrow A by the electric motor 12 when the brake is operated, and is driven to rotate in the direction of arrow B when the brake operation is released. However, a substantially semicircular concave groove 32A is formed on the outer peripheral side of the rotating plate 32, and a ball 37 described later is rollably accommodated in the concave groove 32A.

Reference numeral 33 denotes another rotary plate which constitutes a second rotary member rotatably provided between the sliding surface 10A of the cylindrical case 10 and the rotary plate 32. The rotary plate 33 is It is configured almost similarly to the rotating plate 21 described in the first embodiment,
It is provided integrally with the input shaft 18A of the speed reducer 18. The rotary plate 33 is formed with a circular recess 33A having a hole diameter corresponding to the outer diameter of the rotary plate 32, and the rotary plate 32 is accommodated in the recess 33A.

The rotary plate 33 has a lever receiving hole 33B formed on the outer peripheral side of the recess 33A.
B has both ends open to the recess 33A and the outer peripheral surface of the rotating plate 33. Further, the rotating plate 33 has a lever accommodation hole 33B.
A notch groove 33C is formed on the side of the peripheral wall, and a tip projection 34A of a lever 34 described later is inserted into the notch groove 33C together with the spring 36.

Reference numeral 34 denotes a lever which is swingably disposed in the lever accommodating hole 33B. The lever 34 has a base end connected to the rotating plate 33 via a pin 35 at one side of the lever accommodating hole 33B. A tip projection 34A is integrally formed on the tip side extending to the other side of the lever housing hole 33B.

The upper and lower surfaces of the lever 34 contacting the balls 37, 38 are formed as tapered surfaces 34B, 34C having a predetermined inclination angle, respectively. The lever 34 is formed by the tapered surfaces 34B, 34C from the base end to the distal end. It is formed so as to become gradually wider toward the side. And the lever 34
Transmits rotation together with the spring 36 and the balls 37 and 38.
The restricting portion is configured to swing upward and downward between a standby position shown in FIG. 8 and a lift position shown in FIGS. 9 and 10.

Numeral 36 denotes a spring as biasing means disposed in a notched groove 33C of the rotary plate 33 via a distal end projection 34A of the lever 34, and the spring 36 is a lever as shown in FIG. The distal end projection 34A is constantly urged downward to hold the lever 34 at the standby position. When the output torque T of the electric motor 12 reaches a reference torque value exceeding the rated torque Tn illustrated in FIG. 6, the spring 36 is elastically compressed and deformed as shown in FIG. This allows swinging displacement.

Reference numerals 37 and 38 denote lever housing holes 3 of the rotating plate 33.
3B are balls housed together with the lever 34, the balls 37 and 38 are made of steel balls or the like having high rigidity, and the lower ball 37 is rollably housed in the groove 32A of the rotating plate 32. I have. On the other hand, the upper ball 38 is the cylindrical case 1
0 between the sliding surface 10A and the lever 34, and the lever 3
While lever 4 is at the standby position shown in FIG.
Is placed in a free state.

Here, the rotating plate 32 is driven by the electric motor 12.
When the ball 37 is driven to rotate in the direction of arrow A, the ball 37 transmits a rotating force to the rotating plate 33 via the lever 34 and the spring 36, and rotates the rotating plate 33 together with the rotating plate 32 in the direction of arrow A. If a torque exceeding the reference torque value acts between the rotating plates 32 and 33 during this process, the ball 37 lifts the lever 34 against the spring 36 as shown in FIG. Relative to the rotary plates 32 and 33 at the lift position of the lever 34 shown in FIG.

When the rotary plate 33 is forcibly rotated in the direction of arrow B by the angle γ shown in FIG. 10 when the lever 34 is at the lift position shown in FIG. 9, the ball 38 slides on the cylindrical case 10. The rotating plate 33 is clamped between the moving surface 10A and the lever 34 to restrain the rotating plate 33 against the sliding surface 10A of the cylindrical case 10. Thereby, the rotation of the rotating plate 33 in the direction indicated by the arrow B is restricted, and the pressing force is maintained together with the lever 34 and the balls 37 and 38 during the brake operation.

On the other hand, in this state, when the electric motor 12 is rotated in the reverse direction to release the brake operation, and the rotary plate 32 is driven to rotate in the direction of arrow B, the rotary plate 32 moves relative to the rotary plate 33 in FIG. After the relative rotation by the angle β shown in FIG. 8, the ball 37 is moved to the lever accommodation hole 33B as shown in FIG.
The lever 34 is pushed back from the lift position in FIG. 10 to the standby position in FIG. 8 by the spring 36. Thereby, the rotating plate 3 with respect to the cylindrical case 10
3 is automatically released, the pressing force is released, and the rotating plates 32 and 33 are integrally rotatable in the cylindrical case 10 in the direction of arrow B.

Thus, in the present embodiment having such a structure, substantially the same operation and effect as those of the first embodiment can be obtained. In the present embodiment, in particular, the pressing force holding mechanism and the pressing force Rotation control device 3 also serving as pressure release mechanism
1 comprises rotating plates 32 and 33, a lever 34, a spring 36, balls 37 and 38, and the like. Until the output torque T of the electric motor 12 reaches a reference torque value exceeding the rated torque Tn illustrated in FIG. The lever 36 is held at the standby position by 36, and the rotating plates 32 and 33 are rotated substantially integrally.

As a result, the electric motor 1
2 can prevent the holding operation of the pressing force from being performed unnecessarily when the output torque T does not rise to the reference torque value, for example, at the time of a soft mild brake operation, and the brake control performance at a low torque. Can be improved.

Even when the output torque T of the electric motor 12 exceeds the reference torque value, the lever 34 is lifted by the ball 37 against the spring 36 as shown in FIG. The rotation plate 33 is rotated in the direction of arrow B by the angle γ shown in FIG. Moving surface 1
0A and the lever 34, the rotating plate 33 can be restrained against the sliding surface 10A of the cylindrical case 10, and
The rotation of the rotating plate 33 in the direction indicated by the arrow B can be restricted, and the pressing force holding operation during the brake operation can be stabilized.

In each of the above embodiments, the case where the brake device is applied to a floating caliper type disk brake has been described as an example. However, the present invention is not limited to this. It may be applied to other brake devices.

[0073]

As described in detail above, according to the first aspect of the present invention, the pressing force generating means provided in the brake housing is provided with a feed screw mechanism for converting rotation of the electric motor into axial displacement of the piston. , Comprising a pressing force holding mechanism and a pressing force releasing mechanism, while driving the piston of the feed screw mechanism in the direction of increasing the pressing force by the torque of the electric motor,
Since the pressing force is held by the pressing force holding mechanism even when the torque of the electric motor expires, when driving the piston of the feed screw mechanism in the direction of increasing the pressing force,
For example, the torque of the electric motor is instantaneously increased to a torque value equal to or higher than the rated torque, and the pressing force of the piston can be held in a sufficiently increased state, and the friction member is strongly pressed by the piston against the rotating member. You can continue.

Accordingly, the electric motor can be driven to rotate at a torque equal to or higher than the rated torque during the brake operation, and even if the electric motor is stopped in a state where the pressing force by the friction member is sufficiently increased, a high pressing force is maintained by the pressing force holding mechanism. The pressure can be maintained, and the time for energizing the electric motor can be reliably reduced. Also, compared with the conventional technology using an irreversible mechanism such as a worm gear, the mechanical efficiency at the time of torque transmission can be greatly improved, the electric motor can be reduced in size, the whole device can be reduced in weight, and power consumption can be reduced. Can be.

According to the second aspect of the present invention, the pressing force holding mechanism is constituted by the first and second rotating bodies and the rotation transmitting / restricting portion, and the rotation transmitting / restricting portion always generates the pressing force by the torque from the electric motor. The second rotating body is rotated through the first rotating body, and when the torque of the electric motor expires, the second rotating body is rotated.
The rotation body is restrained to the brake housing side and the rotation in the reverse direction is restricted. Therefore, when the electric motor is rotated in one direction to drive the piston of the feed screw mechanism in the direction of increasing the pressing force, the first rotation is performed. The rotation of the rotating body can be transmitted to the second rotating body via the rotation transmitting / regulating section, and for example, the pressing force of the piston is reduced by instantaneously increasing the torque of the electric motor to a torque value equal to or higher than the rated torque. It can be increased sufficiently. Then, when the rotation of the electric motor is stopped (revoked) in this state, the second rotating body can be restrained to the brake housing side by the rotation transmitting / regulating section, and the second rotating body is moved in the reverse direction (reduction of the pressing force). Direction), the pressing force holding mechanism can be operated to hold the pressing force, and the friction member can be kept pressed strongly against the rotating member by the piston.

Further, according to the third aspect of the present invention, the rotation transmission
The second rotating body is rotated in one direction together with the first rotating body until the torque of the electric motor reaches the rated torque by the restricting portion, and when the torque exceeds the rated torque, the first rotating body is moved to the second rotating body.
Is allowed to rotate relative to the rotating body by a predetermined angle, and even if the torque of the electric motor expires in this state, the second rotating body is restrained on the brake housing side and Since the rotation is restricted, the torque of the electric motor does not increase to the rated torque or more when the brake is operated. For example, it is possible to prevent the holding operation of the pressing force from being performed unnecessarily during a soft mild brake operation. The brake control performance can be improved at low torque.

[Brief description of the drawings]

FIG. 1 is a plan view showing a disc brake according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the disc brake as seen from the direction of arrows II-II in FIG.

FIG. 3 is an enlarged cross-sectional view showing a main part of the rotation control device, as viewed from a direction indicated by arrows III-III in FIG. 2;

FIG. 4 is a sectional view similar to FIG. 3, showing a rotation control device during a brake operation.

FIG. 5 is a sectional view similar to FIG. 3, showing a state in which the pressing force is held;

FIG. 6 is a characteristic diagram showing torque characteristics of the electric motor.

FIG. 7 is an essential part enlarged sectional view showing a rotation control device for a disk brake according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view substantially similar to FIG. 7, showing a state when a brake operation is released.

FIG. 9 is a cross-sectional view similar to FIG. 8, showing a state where a spring is compressed beyond a reference torque during a brake operation.

FIG. 10 is a cross-sectional view similar to FIG. 8, showing a holding state of a pressing force.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Carrier 2 Disk (rotating member) 4 Caliper (brake housing) 5 Inner leg part 5A Piston sliding hole 10 Cylindrical case 12 Electric motor 13 Pressing force generator (pressing force generating means) 14 Piston 15 Screw rod (feed screw mechanism) 18) Reduction gear 19, 31 Rotation control device (pressing force holding mechanism, pressing force releasing mechanism) 20, 32 Rotating plate (first rotating body) 21, 33 Rotating plate (second rotating body) 22, 34 Lever ( Rotation transmission / regulation section) 24, 37, 38 Ball 25 Friction pad (friction member) 36 Spring

Claims (3)

[Claims] 1. A brake housing, an electric motor provided in the brake housing, pressing force generating means for generating an axial pressing force by rotation of the electric motor,
An electric brake device comprising a friction member which is pressed toward a rotating member by the pressing force generating means and applies a braking force to the rotating member, wherein the pressing force generating means controls the rotation of the electric motor in an axial direction of a piston. A feed screw mechanism that converts the displacement into a displacement and presses the friction member toward the rotating member by the piston; and driving the piston of the feed screw mechanism in the direction of increasing the pressing force by the torque of the electric motor. A pressing force holding mechanism for holding the pressing force when the torque of the motor expires, and releasing the pressing force by the pressing force holding mechanism when the electric motor rotates in the reverse direction, and the feed screw is driven by the torque of the electric motor. An electric brake device comprising: a pressing force release mechanism that allows a piston of the mechanism to be driven in a direction of decreasing the pressing force. 2. The pressing force holding mechanism is provided so as to be relatively rotatable between a first rotating body that rotates integrally with the electric motor, and the first rotating body and a brake housing. A second rotating body connected to a rotating part of the mechanism;
The second rotating body is provided in the brake housing and provided between the first and second rotating bodies, and always rotates the second rotating body via the first rotating body by torque from the electric motor. 2. The electric brake device according to claim 1, further comprising: a rotation transmission / regulation section that restricts the rotation in the reverse direction by restricting the second rotating body to the brake housing when the torque of the electric motor expires. . 3. The rotation transmission / restriction unit rotates the second rotating body in one direction together with the first rotating body until the torque of the electric motor reaches a rated torque, and when the torque exceeds the rated torque. Allowing the first rotating body to rotate relative to the second rotating body by a predetermined angle,
The electric brake device according to claim 2, wherein when the torque of the electric motor expires in this state, the second rotating body is restricted to a brake housing side to restrict rotation in a reverse direction.