JPH11101283A - Motor-driven brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform brake operation and release operation with high responsiveness by speedily moving a friction member, such as a friction pad, by a distance equivalent to a pad clearance both during brake operation and during the release of a brake. SOLUTION: In this device, a reduction gear 18 and a centrifugal clutch 23 arranged between a screw rod 14 to convert rotation of an electric motor into displacement in the axial direction of a piston 13. Further, a one-way clutch 24 to selectively release the transmission of rotation between the electric motor 11 and the reduction gear 18 is arranged between the motor shaft 11A of the electric motor 11 and the input shaft 20 of the reduction gear 18. When the electric motor 11 is rotated at a high speed in a state that a rotation load is low, the central clutch 23 is automatically operated, and the rotation of the electric motor 11 is directly transmitted to the screw rod 14 through the centrifugal clutch 23, a drum 15, and each pivot 17.

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 JP-A-7-301291.

[0003] An electric brake device of this type according to the prior art includes a brake housing having a cylinder bore formed therein, a piston slidably inserted in the cylinder bore of the brake housing, and an electric motor in the brake housing. A speed reducer provided to reduce the rotation of the electric motor, a feed screw mechanism provided between the output shaft of the speed reducer and the piston, and converting the rotation of the output shaft into an axial displacement of the piston, A friction pad which is pressed toward the disk by the piston to apply a braking force to the disk.

[0004] The reduction gear is provided with a reduction ratio switching means comprising a one-way clutch or the like, and the output shaft is integrated with the electric motor while the axial thrust force acting on the output shaft of the reduction gear is small. The output shaft is rotated at high speed and low torque, and when the thrust force is increased, the output shaft is rotated at low speed and high torque with a constant reduction ratio.

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 feed screw mechanism converts the rotation of the electric motor into an axial displacement of a piston, and applies a braking force to the vehicle via the disk by pressing the friction pad toward the surface of the disk with the piston. ing.

In this case, in the initial stage of the brake operation, the thrust force as the brake reaction force acting on the output shaft of the speed reducer is small until the friction pad comes into contact with the disk.
For this reason, the output shaft of the speed reducer is rotated at high speed without substantially reducing the rotation of the electric motor by the speed reduction ratio switching means, and reaches the position where the friction pad comes into contact with the disk via the piston by the feed screw mechanism. Displace immediately by the pad clearance.

When the friction pad is in contact with the disk, the piston receives a brake reaction force from the disk via the friction pad, and the brake reaction force acts on the output shaft of the speed reducer as a thrust force. Therefore, the reduction ratio is switched by the reduction ratio switching means, and the output shaft is rotated at a low speed in a high torque state where the rotation of the electric motor is reduced. Thus, the output shaft of the speed reducer strongly presses the piston in the axial direction via the feed screw mechanism, and the pressing force can increase the braking force applied to the disk via the friction pad.

[0008]

In the above-described prior art, the friction pad in the standby position is quickly displaced to the braking position in contact with the disk during the brake operation, and the output is output when the brake reaction force is applied thereafter. Since the rotation of the shaft is decelerated, the friction pad can be reliably pressed against the disc against the brake reaction force, and there is an advantage that a large rotation load can be prevented from acting on the electric motor. There is a problem that responsiveness when releasing is poor.

That is, when the driver of the vehicle releases the depression operation of the brake pedal in order to stop the brake operation, the electric motor in the brake housing is rotated in a direction opposite to that at the time of the brake operation. However, when the electric motor starts reverse rotation, since the brake reaction force from the friction pad is acting on the output shaft of the speed reducer via the feed screw mechanism, this output shaft has a lower speed (deceleration) than the electric motor. Is rotated in the opposite direction.

In this case, the output shaft is reversely rotated via the speed reducer even after the friction pad has started to slightly separate from the disk without switching the speed reduction ratio by the speed reduction ratio switching means. Therefore, when the brake operation is released, there is a problem that the friction pad cannot be quickly returned from the braking position to the standby position by the pad clearance.

The present invention has been made in view of the above-described problems of the prior art, and the present invention has been described in connection with a case where a friction member such as a friction pad is moved between a standby position and a braking position in both cases of braking operation and braking release. The object of the present invention is to provide an electric brake device which can move quickly by a distance corresponding to a pad clearance, can perform a brake operation and a release operation with high responsiveness, and can improve operability and safety. And

[0012]

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 structure 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 toward the feed screw mechanism, a speed reducer that is provided between the feed screw mechanism and the electric motor, that reduces the speed of rotation of the electric motor and transmits the rotation to the feed screw mechanism; and the electric motor and the feed screw mechanism. And operates when the rotation speed of the electric motor reaches a predetermined set speed, transmits the rotation of the electric motor to the feed screw mechanism, and waits until the set speed is reached. A centrifugal clutch that is in a state to release the rotation transmission to the feed screw mechanism, and is provided between the electric motor and the speed reducer. When the electric motor rotates in one direction, the electric motor rotates from the electric motor. To transmit the rotational force towards the speed machine,
When the motor rotates in the reverse direction, the motor is constituted by rotation transmission switching means for transmitting a rotational force from the speed reducer to the electric motor.

With the above structure, the rotational load acting on the electric motor is small until the friction member comes into contact with the rotating member during the brake operation, and the electric motor rotates in one direction at a speed higher than the set speed. Therefore, the centrifugal clutch operates to directly transmit the rotation of the electric motor to the feed screw mechanism, and the rotation of the electric motor is transmitted to the feed screw mechanism via the centrifugal clutch without passing through the speed reducer. For this reason, the feed screw mechanism is driven at a high speed, and the friction member is quickly advanced by the piston to the braking position in contact with the rotating member.

When the friction member comes into contact with the rotating member, the rotational load of the electric motor increases, and the rotational speed of the electric motor becomes lower than the set speed. Therefore, the rotation transmission by the centrifugal clutch is released, and the rotation of the electric motor is stopped. It is transmitted to the feed screw mechanism via the speed reducer by the rotation transmission switching means. As a result, the feed screw mechanism is driven at low speed with high torque,
The friction member can be strongly pressed against the rotating member by the piston.

On the other hand, when the electric motor is reversely rotated to release the braking force when the brake operation is stopped, first, the reverse rotation force is temporarily applied to the speed reducer by the brake reaction force, so that the rotation transmission switching means is used. Temporarily allows the transmission of rotation between the electric motor and the reducer. Thereby, the reverse rotation of the electric motor is transmitted to the feed screw mechanism via the speed reducer, and the piston of the feed screw mechanism can be driven in the direction of retracting from the rotary member together with the friction member, and the pressing force of the friction member on the rotary member is reduced. It can be reliably reduced.

When the friction member is slightly separated from the rotating member, the brake reaction force is lost and the rotation transmission switching means cancels the rotation transmission between the electric motor and the speed reducer, and the rotational load of the electric motor is reduced. Since the electric motor rotates rapidly at a speed higher than the set speed, the centrifugal clutch automatically operates, and the rotation of the electric motor is transmitted to the feed screw mechanism via the centrifugal clutch, whereby the electric motor rotates. The friction member can be retracted so as to be quickly separated from the rotating member.

A feature of the structure adopted by the invention of claim 2 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 toward
A speed reducer provided between the feed screw mechanism and the electric motor, for reducing rotation of the electric motor and transmitting the rotation to the feed screw mechanism; and a speed reducer provided between the electric motor and the feed screw mechanism. A cam mechanism that converts the rotation of the motor and drives the piston of the feed screw mechanism in the axial direction, and is provided between the cam mechanism and the electric motor until the torque of the electric motor reaches a predetermined reference torque. And a torque limiter for transmitting the torque of the electric motor to the cam mechanism and releasing the torque transmission to the cam mechanism when the torque exceeds the reference torque.

With the above structure, the torque (rotational load) acting on the electric motor is small until the friction member comes into contact with the rotating member during the brake operation, and the electric motor rotates at a torque lower than the reference torque of the torque limiter. Therefore, the rotation of the electric motor is transmitted to the cam mechanism via the torque limiter, and the piston of the feed screw mechanism can be largely driven in the axial direction by the cam mechanism, and the friction member abuts the rotating member by the piston. It is possible to quickly advance to the braking position.

When the friction member comes into contact with the rotating member, the torque of the electric motor increases and exceeds the reference torque of the torque limiter. Therefore, the transmission of torque to the cam mechanism is released by the torque limiter, and the rotation of the electric motor is stopped. Is transmitted to the feed screw mechanism only through the speed reducer. Accordingly, the feed screw mechanism is driven at a low speed with a high torque, and the friction member can be strongly pressed 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, this rotation is transmitted to the feed screw mechanism via the speed reducer, and the piston of the feed screw mechanism is moved together with the friction member. It can be driven in the direction of retreating from the rotating member, and the pressing force of the friction member on the rotating member can be reliably reduced. When the friction member is slightly separated from the rotating member, the electric motor starts to rotate at a torque lower than the reference torque of the torque limiter due to a sudden decrease in the rotational load, so that the electric motor rotates through the torque limiter. The power is transmitted to the cam mechanism, and the piston of the feed screw mechanism can be largely driven in the backward direction by the cam mechanism, so that the friction member can be quickly separated from the rotating member.

Further, a feature of the structure adopted by the invention of claim 3 is that the pressing force generating means includes a feed screw mechanism for converting rotation of the electric motor into axial displacement of the piston,
A speed reducer provided between the feed screw mechanism and the electric motor, for reducing the rotation of the electric motor and transmitting the rotation to the feed screw mechanism; and a speed reducer for directly transmitting the rotation of the electric motor to a piston of the feed screw mechanism. A connection shaft connected to the piston and allowing relative displacement of the piston in the axial direction, provided between the connection shaft and the electric motor, until the torque of the electric motor reaches a predetermined reference torque. A torque limiter that transmits the torque of the electric motor to a connection shaft and cancels the transmission of torque to the connection shaft when the torque exceeds the reference torque, and is provided between the piston of the feed screw mechanism and the friction member. Allows the rotation of the piston via the connecting shaft, and when a brake reaction force acts from the friction member toward the piston side during a brake operation, the brake reaction force Lies in the configuration of a clutch mechanism for restricting the rotation of the piston.

Thus, the torque acting on the electric motor is small until the friction member comes into contact with the rotating member during the brake operation, and the electric motor rotates at a torque lower than the reference torque of the torque limiter and the clutch mechanism. Is in a state that allows the rotation of the piston through the connection shaft, so that the rotation of the electric motor can be transmitted to the piston of the feed screw mechanism through the torque limiter and the connection shaft, and the piston is rotated with the connection shaft in the axial direction. The friction member can be quickly advanced to the braking position where the friction member contacts the rotating member.

When the friction member contacts the rotating member, the clutch mechanism regulates the rotation of the piston by the braking reaction force at this time, and the torque of the electric motor increases to a level exceeding the reference torque of the torque limiter.
The transmission of torque to the connecting shaft is released by the torque limiter, and the rotation of the electric motor is transmitted to the feed screw mechanism via only the speed reducer. Accordingly, the feed screw mechanism is driven at a low speed with a high torque, and the friction member can be strongly pressed against the rotating member by the piston.

On the other hand, when the electric motor is rotated in reverse to release the braking force when the brake operation is stopped, this rotation is transmitted to the feed screw mechanism via the speed reducer, and the piston of the feed screw mechanism is moved together with the friction member. It can be driven in the direction of retreating from the rotating member, and the pressing force of the friction member on the rotating member can be reliably reduced. When the friction member is slightly separated from the rotating member, the brake reaction force drops sharply, and the rotation of the piston is allowed by the clutch mechanism, and the rotating load of the electric motor also drops sharply, so that the torque becomes lower than the reference torque of the torque limiter. It starts to rotate with low torque. Thereby, the rotation of the electric motor can be transmitted to the piston of the feed screw mechanism via the torque limiter and the connection shaft, and the piston can be rotated with the connection shaft and largely driven in the retreating direction, so that the friction member is quickly separated from the rotation member. Can be done.

On the other hand, a feature of the structure adopted by the invention of claim 4 is that the pressing force generating means is brought into contact with the friction member to press the friction member in the axial direction, and the rotation with respect to the friction member is regulated. And a feed screw member whose base end side is screwed into the brake housing and whose distal end side extends toward the piston, and which is provided between the feed screw member and the electric motor. The rotation of the motor is transmitted to the feed screw member, and a rotation transmission shaft that allows the feed screw member to be relatively displaced in the axial direction is provided between the piston and the feed screw member. A cam mechanism for driving a piston in the axial direction via a screw member, a sleeve slidably provided in the brake housing, and rotatably supporting a distal end side of the feed screw member; An adjuster that rotatably supports the feed screw member in the housing and adjusts relative to the feed screw member in the axial direction in order to adjust the wear of the friction member, and is provided between the adjuster and the brake housing; A ratchet mechanism for allowing the adjuster to be displaced toward the friction member together with the feed screw member and restricting the adjuster from being displaced in the opposite direction.

Thus, the rotation of the electric motor is transmitted to the cam mechanism via the rotation transmitting shaft and the feed screw member until the friction member comes into contact with the rotating member during the brake operation, and the piston is moved by the cam mechanism. It can be largely driven in the axial direction, whereby the friction member can be quickly advanced to the braking position in contact with the rotating member. When the friction member comes into contact with the rotating member, the operation of the cam mechanism is substantially stopped, but the rotation of the electric motor is transmitted to the feed screw member via the rotation transmitting member, so that the feed screw member is rotated. Is pushed in the axial direction by the amount of the screw lead, and the rotation of the electric motor can be converted into a pressing force on the piston in a decelerated state, and the piston can strongly press the friction member against the rotating member.

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 rotation is transmitted to the feed screw member via the rotation transmitting member, so that the feed screw member becomes a screw lead. The piston is retracted in the axial direction by the distance, and the piston can be driven in the direction of retracting from the rotating member together with the friction member, so that the pressing force of the friction member on the rotating member can be reliably reduced. When the friction member is slightly separated from the rotating member, the cam mechanism is operated according to the rotation of the feed screw member, the piston can be largely driven in the retreating direction, and the friction member can be quickly separated from the rotating member.

If the friction member wears out while repeating the brake operation as described above, the ratchet mechanism allows the adjuster to be displaced toward the friction member together with the feed screw member. The gap between the rotating member and the rotating member can be automatically adjusted by the adjuster. Furthermore, even when the thickness of the rotating member fluctuates due to thermal expansion or the like, the cam mechanism provided between the feed screw member and the piston can absorb the thickness fluctuation of the rotating member, and when the braking force is released. The friction member can be reliably separated from the rotating member.

[0030]

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 3 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 has a pair of arms 1A extending toward the outer side. doing. Each arm 1A of the carrier 1 straddles the outer peripheral side of a disk 2 as a rotating member that rotates integrally with a vehicle wheel (not shown). Is slidably supported.

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 sliding pins, and reference numeral 4 denotes a brake housing slidably mounted on each arm 1A of the carrier 1 via the sliding pins. As shown in FIG. 2, the caliper 4 is located on one side (inner side) of the disk 2 and has an inner leg portion 5 having a piston sliding hole 5A and the like,
A claw portion 6 located on the other side (outer side) of the disk 2, a bridge portion 7 for connecting the inner leg portion 5 to the claw portion 6 on the outer side across the outer peripheral side of the disk 2, and an inner leg portion as shown in FIG. Part 5
A pair of mounting portions 9, which are provided on both sides of the disk 2 in the circumferential direction of the disc 2 and the sliding pins are fixed by bolts 8, 8.
9.

Here, a receiving hole 5B having a diameter larger than that of the piston sliding hole 5A is formed in the inner leg portion 5 at a position behind the piston sliding hole 5A. An electric motor 11 and a speed reducer 18 to be described later are housed.

10 is a piston sliding hole 5A of the inner leg 5
The lid 10 has a configuration in which the housing hole 5B is removably closed at a position opposite to the above, the lid 10 forms a brake housing together with the caliper 4, and the electric motor 11 and the like are positioned in the storage hole 5B. I have.

Reference numeral 11 denotes an electric motor provided in the accommodation hole 5B of the inner leg portion 5. The electric motor 11 is driven by an external control unit (not shown) to rotate the motor shaft 11A. , Piston 13 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 a rotation angle or rotation corresponding to the operation amount is output on the control unit side. A control signal is output so as to rotate the electric motor 11 by a number, and power is supplied.

Reference numeral 12 denotes the inner leg 5 together with the electric motor 11.
The pressing force generator 12 is provided as a pressing force generating means provided in the accommodation hole 5B.
3. Screw rod 14, speed reducer 18, centrifugal clutch 23 described later
And a one-way clutch 24 and the like, and moves the piston 13 axially forward or backward when the motor shaft 11A rotates.

13 is a piston sliding hole 5A of the inner leg 5
A piston slidably provided in the piston 13
Constitutes a feed screw mechanism together with the screw rod 14, and a screw hole 13 </ b> A screwed to the screw rod 14 is formed on the inner peripheral side. Then, the piston 13 is driven by the electric motor 11 through the screw rod 14, and the friction pad 25 is
To slide in the axial direction in the piston sliding hole 5A. Further, for example, a rotation stopper (not shown) for restricting rotation of the piston 13 around the screw rod 14 is provided between the front end side of the piston 13 and a friction pad 25 on the inner side described later. I have.

A screw rod 14 constitutes a feed screw mechanism together with the piston 13. The screw rod 14 has a thread formed on the outer peripheral side, and is screwed into a screw hole 13A of the piston 13. A rotary plate 14A is integrally provided on the base end side of the threaded rod 14, and the rotary plate 14A is configured to rotate integrally with the drum 15 via each support shaft 17 described later. The screw rod 14 is configured to convert the rotation of the electric motor 11 into an axial displacement of the piston 13 by transmitting the rotation of the electric motor 11 via the drum 15 or the like.

Reference numeral 15 denotes a drum rotatably disposed in the accommodation hole 5B of the inner leg portion 5 via a bearing 16. The drum 15 has a closed cylinder so as to surround the centrifugal clutch 23 and the one-way clutch 24 from outside. On the lid 15A side, for example, three to four support shafts 17, 17,... Are integrally provided between the screw bar 14 and the rotary plate 14A. The drum 15 rotates integrally with the screw rod 14 and each support shaft 17 in the accommodation hole 5B of the inner leg 5.

Reference numeral 18 denotes a speed reducer located between the rotary plate 14A and the drum 15 and disposed in the housing hole 5B of the inner leg 5, and the speed reducer 18 is integrally formed on the peripheral wall of the housing hole 5B. A ring-shaped internal gear 19 provided, an input shaft 20 connected to a motor shaft 11A of the electric motor 11 via a one-way clutch 24, provided on a tip end side of the input shaft 20;
A sun gear 21 that rotates integrally with the input shaft 20, and a plurality of planetary gears 22, 2 that are provided in a meshing state between the sun gear 21 and the internal gear 19 and are rotatably supported by the support shafts 17.
2, and so on.

Here, when the rotation of the electric motor 11 is transmitted to the input shaft 20 of the speed reducer 18, each planetary gear 22 meshing with the sun gear 21 revolves around the sun gear 21 while rotating, and each planetary gear 22 rotates. The revolution of the gear 22 is transmitted to the rotary plate 14 </ b> A of the screw rod 14 via each support shaft 17. As a result, the speed reducer 18 transmits the rotation of the input shaft 20 to the screw rod 14 with a constant reduction ratio, generates a large torque on the screw rod 14, and exhibits a function of reducing the rotational load of the electric motor 11. is there.

When the input shaft 20 penetrating through the center of the lid 15A of the drum 15 is set in a free (free) rotation state by the one-way clutch 24, each planetary gear 22 becomes the sun gear 21 and the internal gear 19 and In this state, the rotation of the electric motor 11 is transmitted to the drum 15 via the centrifugal clutch 23, and the drum 15 rotates integrally with the motor shaft 11A. High speed to the screw rod 14 via the support shaft 17,
It is transmitted with low torque.

Reference numeral 23 denotes a motor shaft located in the drum 15
As shown in FIG. 3, the centrifugal clutch 23 includes a rotating body 23A integrally provided on the outer circumference of the motor shaft 11A, and a centrifugal clutch 23 provided on the outer circumference of the rotating body 23A. A plurality of movably connected connecting arms 23B,
, And a plurality of contacts 23C, 23 provided on the distal end side of each of the connecting arms 23B and frictionally contacting the inner peripheral surface of the drum 15 by centrifugal force when the rotating body 23A rotates.
, And a plurality of tension springs 23D, 23D,..., Which are disposed between the respective contacts 23C and the rotating body 23A and are constantly biased in a direction to separate the respective contacts 23C from the drum 15.
It is composed of

Here, each tension spring 23D determines the set speed when the centrifugal clutch 23 operates, and
Until the rotation speed of 1A reaches the set speed, each contact 23C is held in a standby state separated from the drum as shown in FIG. When the rotation speed of the motor shaft 11A exceeds the set speed, the centrifugal force acting on each contact 23C overcomes the spring force, so that each contact 23C comes into frictional contact with the inner peripheral surface of the drum 15, and
Is transmitted so that the motor rotates integrally with the motor shaft 11A.

A one-way clutch 24 is provided between the motor shaft 11A of the electric motor 11 and the input shaft 20 of the speed reducer 18 as a rotation transmission switching means. When the rotation of the piston 1 is performed, the rotational force is transmitted from the motor shaft 11 </ b> A toward the input shaft 20, and the motor 11 rotates in the reverse direction (the piston 1 rotates).
At the time of rotation in the direction in which the motor shaft 3 moves backward, the torque is transmitted from the input shaft 20 toward the motor shaft 11A.

That is, when the electric motor 11 is rotating forward, a torque is first transmitted from the motor shaft 11A to the input shaft 20, but when the rotation load of the electric motor 11 is small, the motor shaft 11A is rotated at a high speed. When the speed exceeds the set speed of the centrifugal clutch 23, the rotation of the electric motor 11 is transmitted to the screw rod 14 via the drum 15 and each support shaft 17 by the centrifugal clutch 23. The support shaft 17 (the planetary gear 22) is rotated following the rotation of the motor shaft 11A and the input shaft 2 during this time.
The rotation transmission between 0 and 0 is released by the one-way clutch 24.

When the rotation load of the electric motor 11 increases and the rotation speed of the motor shaft 11A falls below the set speed, the rotation transmission by the centrifugal clutch 23 is released and the rotation of the shaft 15 from the drum 15 to the support shafts 17 is stopped. Since the rotational force is lost, the input shaft 20 is not rotated by the rotational force from each support shaft 17 side.
A rotates the input shaft 20 via the one-way clutch 24.
When the speed reducer 18 operates, the rotation of the electric motor 11 is transmitted to the screw rod 14 at a low speed and a high torque.

On the other hand, when the electric motor 11 is rotated in the reverse direction, while the brake reaction force from the piston 13 is large,
One-way clutch 24 from input shaft 20 side of reducer 18
A reverse rotation force acts on the motor, and rotation is temporarily transmitted between the electric motor 11 and the speed reducer 18. However, when the friction pad 25 is slightly separated from the disk 2, the brake reaction force is sharply reduced and the reverse rotation force does not act on the one-way clutch 24 from the input shaft 20 side of the speed reducer 18. The rotation transmission between the gear 11 and the speed reducer 18 is released by the one-way clutch 24.

Further, reference numerals 25, 25 denote friction pads serving as a pair of friction members disposed on both sides of the disk 2, and the inner friction pad 25 of the friction pads 25 is Pressed toward one side. 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.

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

First, when the driver of the vehicle depresses the brake pedal, a signal corresponding to the depressing operation amount of the brake pedal is sent to the control unit by a pedal sensor (not shown) provided near the brake pedal. Is output. Then, the control unit outputs a control signal corresponding to the operation amount to the electric motor 11, and drives the electric motor 11 to rotate at a rotation angle or rotation speed corresponding to the operation amount.

During the braking operation, the rotational load acting on the electric motor 11 is small until the inner friction pad 25 comes into contact with the disk 2.
Rotates at a speed higher than the set speed of the centrifugal clutch 23 in the direction indicated by the arrow A in FIG. 3 (one direction), so that the centrifugal clutch 23 operates to rotate the electric motor 11 to the drum 15 and each support. Directly transmitted to the threaded rod 14 via the shaft 17, the one-way clutch 24 releases the rotation transmission between the motor shaft 11A of the electric motor 11 and the input shaft 20 of the speed reducer 18.

That is, when the electric motor 11 rotates in the forward direction, the torque is first transmitted from the motor shaft 11A to the input shaft 20, but when the rotation load of the electric motor 11 is small, the motor shaft 11A rotates at a high speed. When the speed exceeds the set speed of the centrifugal clutch 23, the rotation of the electric motor 11 is transmitted to the screw rod 14 via the drum 15 and each support shaft 17 by the centrifugal clutch 23. The support shaft 17 (the planetary gear 22) is rotated following the rotation of the motor shaft 11A and the input shaft 2 during this time.
The rotation transmission between 0 and 0 is released by the one-way clutch 24.

For this reason, the screw rod 14 is connected to the centrifugal clutch 23.
, And the piston 13 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. Then, the friction pad 25 on the inner side
, The rotational load of the electric motor 11 increases, and the rotational speed of the motor shaft 11A becomes lower than the set speed of the centrifugal clutch.

As a result, the rotation transmission by the centrifugal clutch 23 is released and the rotational force from the drum 15 to each support shaft 17 is lost, so that the input shaft 20 is rotated by the rotational force from each support shaft 17 side. In this state, the rotation of the motor shaft 11A is transmitted to the input shaft 20 via the one-way clutch 24, and the rotation of the electric motor 11 is reduced at a low speed and a high torque by the operation of the speed reducer 18, so that the screw rod 1 is rotated.
4 will be transmitted. Thereby, the screw rod 14
Is driven at a low speed with a high torque, and the friction pads 25 can be pressed strongly against the disk 2 by the piston 13, so that, for example, a braking force can be reliably applied to a running vehicle via the disk 2.

Next, when the depression operation of the brake pedal is released in this state, the electric motor 11 is rotated in the reverse direction by the signal from the pedal sensor. When the electric motor 11 is reversely rotated, a reverse rotational force acts on the one-way clutch 24 from the input shaft 20 side of the speed reducer 18 while the brake reaction force from the piston 13 side is large. The rotation of the electric motor 11 is transmitted to the screw rod 14 via the speed reducer 18 and the piston 13 is
At the same time, it can be driven in the direction of retreating from the disk 2, and the pressing force of the friction pad 25 on the disk 2 can be reliably reduced.

However, when the friction pad 25 is slightly separated from the disk 2, the brake reaction force is sharply reduced, and the reverse rotation force does not act on the one-way clutch 24 from the input shaft 20 side of the speed reducer 18. The transmission of rotation between the electric motor 11 and the speed reducer 18 is released by the one-way clutch 24. And the friction pad 25
Is slightly separated from the disk 2, the electric motor 11
The rotational load of the electric motor 11 rapidly decreases, and the electric motor 11 is driven at a speed higher than the set speed of the centrifugal clutch 23 as indicated by an arrow B in FIG.
It rotates in the direction (reverse direction).

As a result, the centrifugal clutch 23 is automatically operated, and the rotation of the electric motor 11 is transmitted to the threaded rod 14 via the centrifugal clutch 23, whereby the friction pad 2
5 can be quickly retracted from the disk 2 and separated from the disk 2 by the pad clearance C.

Thus, according to the present embodiment, the reduction gear 18 and the centrifugal clutch are provided between the screw shaft 14 for converting the rotation of the electric motor 11 into the axial displacement of the piston 13 and the motor shaft 11A of the electric motor 11. 23, and a one-way clutch 24 is provided between the motor shaft 11A of the electric motor 11 and the input shaft 20 of the speed reducer 18 for selectively releasing the rotation transmission between the electric motor 11 and the speed reducer 18. When the electric motor 11 is rotated at a high speed with a small rotational load, the centrifugal clutch 23 is automatically operated and the rotation of the electric motor 11 is controlled by the centrifugal clutch 2.
3, can be directly transmitted to the screw rod 14 via the drum 15 and each support shaft 17 and the like.

As a result, the piston 13 can be advanced or retracted toward the disk 2 at an early stage on the inner leg 5 side of the caliper 4 both when the brake is operated and when the brake is released. The friction pad 25 can be promptly moved by the pad clearance C between the braking position and the braking position.

Therefore, according to the present embodiment, the moving speed of the friction pad 25 (piston 13) between the standby position and the braking position is ensured regardless of whether the brake is operated or the brake is released. In addition to being able to improve the responsiveness of the brake operation, the friction pad 25 can be returned to the early stage even when the brake operation is released, and the responsiveness can be increased to greatly improve the operability and safety.

FIGS. 4 to 9 show a second embodiment of the present invention. The feature of this embodiment is that a cam mechanism or the like is provided in the pressing force generating means, and the rotation of the electric motor is controlled by the cam mechanism. Is converted into an axial displacement, and the piston of the feed screw mechanism is quickly advanced and retracted. In addition,
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 caliper constituting a brake housing which is attached to each arm 1A of the carrier 1 via each sliding pin, and the caliper 31 is the caliper 4 described in the first embodiment. Substantially the same as above
Inner leg 32 having 2A, accommodation hole 32B, etc.
And a claw 33 located on the other side (outer side) of the disc 2
And a bridge portion 34 that straddles the outer peripheral side of the disk 2 and connects the inner leg portion 32 to the outer claw portion 33.

Reference numeral 35 denotes a piston sliding hole 3 of the inner leg 32.
A cover body that removably closes the accommodation hole 32B at a position opposite to 2A. The lid body 35 forms a brake housing together with the caliper 31, and positions a cylindrical case 36 and the like described later in the accommodation hole 32B. It has a configuration. Further, a large-diameter gear 44 and each small-diameter gear 45 described later are accommodated in the lid 35.

Reference numeral 36 denotes a cylindrical case provided in the housing hole 32B of the inner leg 32, and 37 denotes an electric motor housed in the cylindrical case 36. The electric motor 37 is the first embodiment. The motor shaft 37A is rotatably driven by a power supply from a control unit or the like. However, the electric motor 37 has one end of a motor shaft 37A connected to a torque limiter 55 described later, and the other end (not shown) connected to a speed reducer 41 described later.

Reference numeral 38 denotes the inner leg 3 together with the electric motor 37.
A pressing force generating device as a pressing force generating means provided in the second accommodation hole 32B. The pressing force generating device 38 includes a piston 39, a screw rod 40, a speed reducer 41, a cam mechanism 42, a torque limiter 55, and the like, which will be described later. Motor shaft 3
At the time of rotation of 7A, the piston 39 advances or retracts in the axial direction.

Reference numeral 39 denotes a piston sliding hole 3 of the inner leg 32.
2A shows a piston slidably provided in 2A, and the piston 39 is the piston 13 described in the first embodiment.
And a screw hole 39A screwed into the screw rod 40 is formed on the inner peripheral side. The piston 39 is driven by the electric motor 37 via the screw rod 40, and is slid in the axial direction in the piston sliding hole 32A to press the friction pad 25 against the disk 2.
Further, for example, the inner side friction pad 25 and the piston 39
Between them, a detent (not shown) or the like for restricting rotation of the piston 39 around the screw rod 40 is provided.

Reference numeral 40 denotes a threaded rod which constitutes a feed screw mechanism together with the piston 39. The threaded rod 40 has a thread formed on the outer peripheral side, and is screwed into the threaded hole 39A of the piston 39. A spline 40A is formed on the base end side outer periphery of the screw rod 40. The spline 40A is connected to an output shaft 41A of a reduction gear 41, which will be described later, and rotates the screw rod 40 integrally with the output shaft 41A. It is configured to allow the shaft 40 to be displaced relative to the output shaft 41A in the axial direction.

Further, a disk-shaped rotary plate 40B is provided at an axially intermediate portion of the screw rod 40, and the rotary plate 40B rotates integrally with the screw rod 40. Also, the rotating plate 40B
Is configured such that the pressing force in the axial direction is transmitted by the cam mechanism 42, and the screw rod 40 moves in the axial direction together with the piston 39.

Reference numeral 41 denotes the cylindrical case 3 together with the electric motor 37.
6, the reduction gear 41 reduces the rotation of the electric motor 37, and its output shaft 41A is connected to the motor shaft 37.
It rotates at a lower speed and higher torque than A. The output shaft 41A of the speed reducer 41 is connected to the proximal end side of the screw rod 40 via a spline 40A so as to rotate the screw rod 40 integrally and to allow the screw rod 40 to be relatively displaced in the axial direction. Has become.

Reference numeral 42 denotes a cam mechanism disposed between the motor shaft 37A of the electric motor 37 and the screw rod 40. The cam mechanism 42 is located in the lid 35 and fixed to the rotary shaft 43. A large-diameter gear 44 composed of a given spur gear;
4 and a pair of small-diameter gears 45, 45 that are rotatably provided in the cylindrical case 36 and that are located radially outside of the electric motor 37 and the like, and each small-diameter gear 45 is fixed to one end side. The shafts 46, 46, a pair of worm gears 47, 47 provided on the other end side of each of the shafts 46 and integrally rotating with the small-diameter gear 45 via the shaft 46, and the respective worm gears 47 retract as shown in FIG. A pair of cams 48, 48 pivoted between the position and the advanced position shown in FIG.
And each of the cams 48 is rotatably supported on the other end side of the cylindrical case 36 by each support shaft 49 and the like.

At the other end of the cylindrical case 36, bar-shaped stoppers 50 and 51 are provided near the respective cams 48. Each cam 48 has a pin 48A which comes into contact with the stoppers 50 and 51. Are provided integrally. When each cam 48 is rotated to the retracted position shown in FIG. 6, the pin 48A of each cam 48 comes into contact with each stopper 50, so that further rotation of each cam 48 is restricted, and each cam 4 is rotated.
When the pin 8 is rotated to the extended position shown in FIG. 7, the pin 48A of each cam 48 comes into contact with each stopper 51, whereby further rotation of each cam 48 is restricted.

Here, each cam 48 is rotated from the retracted position to the advanced position with a rotation angle exceeding, for example, 90 degrees, and the contact point a at which each cam 48 contacts a thrust plate 52 described later is the maximum of the cam 48. The position is beyond the contour point b. That is, when the thrust plate 52 contacts the cam 48 at the maximum contour point b, the thrust plate 52 advances to the position furthest away from the support shaft 49, and at the advanced position of FIG. Thus, it is slightly pushed back to the support shaft 49 side.

As a result, the electric motor 37 moves the cam mechanism 4
Even when the torque transmission to 2 is released by the torque limiter 55 as described later, the cam 48 receives the spring force from the spring 54 at the contact point a via the thrust plate 52, and the pin 48A is pressed against the stopper 51. Thus, the cam 48 is held at the advanced position in FIG.

Reference numeral 52 denotes an annular thrust plate provided between the rotary plate 40B of the screw rod 40 and each cam 48. The thrust plate 52 is mounted on the rotary plate 40B via a thrust bearing 53, The pressing force from 48 is applied to the rotating plate 40B
And the rotation plate 40B is allowed to rotate relative to the thrust plate 52. The thrust plate 52 does not rotate in the inner leg portion 32, but advances and retreats only in the axial direction by the operation of each cam 48.

Numeral 54 denotes a spring located radially outside the rotary plate 40B and disposed between the inner leg 32 and the thrust plate 52 in a contracted state. The spring 54 connects the thrust plate 52 to each cam 48. The thrust plate 52 is normally returned to the retracted position shown in FIGS. 4 and 6. When the cam mechanism 42 is operated, the spring 54 allows the thrust plate 52 to be pushed to the advanced position shown in FIGS. 5 and 7 by the cam 48. In this state, the thrust plate 52 is turned toward the support shaft 49. By applying an upward turning force in FIG. 7 to the cam 48 via the contact point a while urging the cam 48 in the axial direction, the pin 48A is pressed against the stopper 51 and the cam 48 is advanced as shown in FIGS. Hold in position.

A torque limiter 55 is provided between the motor shaft 37A of the electric motor 37 and the rotary shaft 43 of the cam mechanism 42. The torque limiter 55 has a pair of friction plates 55A and 55A as shown in FIG. 55B and torque setting spring 55
C, and one friction plate 55A is fixed to an end of the rotating shaft 43. The other friction plate 55B is spline-coupled to the motor shaft 37A, and the torque setting spring 55C
Urged by a constant spring force toward the friction plate 55A.

Here, the setting spring 5 of the torque limiter 55
5C is the motor shaft 3 until the torque (rotational force) acting between the friction plates 55A and 55B reaches a certain reference torque.
The torque from 7A is transmitted to the rotating shaft 43 side. When the torque acting between the friction plates 55A and 55B exceeds the reference torque, the displacement of the friction plate 55B in the direction away from the friction plate 55A is set by a setting spring 55C.
Is allowed, and the transmission of torque from the motor shaft 37A toward the rotating shaft 43 is released. Thus, the torque limiter 55 temporarily cancels the transmission of torque from the electric motor 37 to the cam mechanism 42, and prevents the rotational load of the electric motor 37 from becoming excessive.

The disc brake according to the present embodiment has the above-described configuration. Next, the operation of the disc brake will be described.

First, when the driver of the vehicle depresses the brake pedal, a signal corresponding to the depressed operation amount of the brake pedal is sent to the control unit by a pedal sensor (not shown) provided near the brake pedal. The control unit outputs the control signal corresponding to the operation amount to the electric motor 37 so as to rotate the electric motor 37 at a rotation angle or rotation speed corresponding to the operation amount.

During the operation of the brake, the rotational load acting on the electric motor 37 is small until the inner friction pad 25 comes into contact with the disk 2.
Is rotated with a torque smaller than the reference torque of the torque limiter 55, so that the rotation of the motor shaft 37A is controlled by the large-diameter gear 4 of the cam mechanism 42 via the torque limiter 55.
4, transmitted to each small-diameter gear 45, each shaft 46, and each worm gear 47, and each worm gear 47 rotates each cam 48 from the retracted position shown in FIG. 4 to the advanced position shown in FIG.

As a result, each cam 48 of the cam mechanism 42 pushes the thrust plate 52 in the axial direction against the spring 54, and the screw rod 40 moves the thrust plate 52 through the rotary plate 40B.
As a result, the piston 39 is pushed in the axial direction, whereby the piston 39 is also pushed in the axial direction. During this time, the speed reducer 41
May be transmitted from the output shaft 41A to the screw rod 40 via the spline 40A via the spline 40A, and the piston 39 is largely driven in the axial direction by the cam mechanism 42.

That is, while the piston 39 is pushed in the axial direction by the cam mechanism 42, the piston 39 is quickly displaced with a very small pressing force (reaction force) to the piston position S1 shown in FIG. Is between time t0 and time t1 as shown by the characteristic line in FIG. 9, and the piston 39 displaces the pad clearance C of the friction pad 25 in a short time. Then, when each cam 48 reaches the advanced position shown in FIG. 7, the pin 48A comes into contact with the stopper 51, and the cam 48
Is restricted, a rotational load equal to or greater than the reference torque acts on the electric motor 37, and the rotation transmission to the cam mechanism 42 is released by the torque limiter 55.

Then, the inner friction pad 25 is moved together with the piston 39 by the pad clearance C for the disk 2.
When the electric motor 37 starts to contact the disk 2, the rotation of the electric motor 37 is
Informed to 0. Thus, the screw rod 40 is driven at a low speed with a high torque, and the inner friction pad 25 can be strongly pressed against one side of the disk 2 by the piston 39, and the outer friction pad is displaced by sliding the entire caliper 31. 25 can be pressed against the other side surface of the disk 2, so that a braking force can be reliably applied to the vehicle on the way through the disk 2, for example.

During this time, for example, the piston 39 is displaced to the piston position Sa shown in FIG. 8, and the pressing force (reaction force) against the disk 2 by the friction pad 25 is increased to the pressing force Fa. The time during this period is between times t1 and ta as shown by the characteristic line in FIG.

Next, when the depression operation of the brake pedal is released in this state, the electric motor 37 is rotated in the reverse direction by the signal from the pedal sensor. Then, when the electric motor 37 is rotated in the reverse direction, the brake reaction force from the piston 39 first increases, and each cam 48 of the cam mechanism 42 exceeds the maximum contour point b of the cam 48 as illustrated in FIG. It is in contact with the thrust plate 52 at the position of the contact point a.

Therefore, the reverse rotation of the electric motor 37 is transmitted to the cam mechanism 42, and even if each cam 48 starts rotating toward the stopper 50, each cam 4 with respect to the thrust plate 52
Until the contact position 8 passes through the maximum contour point b, the thrust plate 52 is not displaced toward the support shaft 49, and the piston 39 cannot be retracted from the disk 2 by the cam mechanism 42.

However, during this time, the reverse rotation of the electric motor 37 is transmitted to the screw rod 40 via the speed reducer 41, so that the piston 39 can be driven via the speed reducer 41 in the direction of retracting from the disk 2 together with the friction pad 25. , Friction pad 2
5 can reliably reduce the pressing force on the disk 2. This time corresponds to the time tb, tc shown in FIG. 9, and the pressing force (reaction force) acting on the piston 39 is the pressing force F
It will definitely decrease from the level of a.

When the friction pad 25 is slightly separated from the disk 2, the reverse rotation of the electric motor 37 is transmitted to each cam 48 of the cam mechanism 42, and the contact of each cam 48 with the thrust plate 52 illustrated in FIG. The position has already passed the maximum contour point b, and the thrust plate 52 is
As a result, it is pushed back to the support shaft 49 side. Accordingly, the cam mechanism 42 allows the piston 39 to move in the retreating direction via the spring 54 until each cam 48 rotates to the retreat position shown in FIG. 6, and the time tc as shown by the characteristic line in FIG.
, Td can be quickly retracted from the disk 2 in a short time.

In this case, as shown in FIG. 6, the contact of the pin 48A with the stopper 50 is detected by a sensor or the like at the retracted position of the cam 48, and the reverse rotation of the electric motor 37 is automatically performed according to a detection signal from this sensor. By stopping at
The retreat position of the piston 39 can be controlled with high precision, and the pad clearance C can be kept constant. Alternatively, for example, a change in the value of the current flowing through the electric motor 37 may be detected. In this case, a change in torque when the friction pad 25 separates from the disk 2 is taken out as a change in the current value. From this position, pin 4 of cam 48
The electric motor 37 may be rotated in the reverse direction by the amount of rotation until the 8A comes into contact with the stopper 50.

Thus, in this embodiment having the above-described structure, the piston 39 is disc-disposed on the inner leg portion 32 side of the caliper 31 both when the brake is operated and when the brake is released, similarly to the first embodiment. Can be advanced or retracted in a short time toward
Pad 25 between the standby position and the braking position for
Can be quickly moved by the pad clearance C shown in FIG.

In both the case of the brake operation and the case of the brake release, the moving speed of the friction pad 25 (piston 39) between the standby position and the braking position can be reliably increased, and the response of the brake operation can be improved. In addition to improving the operability, the friction pad 25 can be returned to the early stage even when the brake operation is released, and the responsiveness can be increased, and the operability and safety can be greatly improved.

FIGS. 10 and 11 show a third embodiment of the present invention. The feature of this embodiment is that the pressing force generating means is constituted by a feed screw mechanism, a clutch mechanism and the like. The structure is such that the relative rotation between the piston and the friction pad of the mechanism is controlled by the clutch mechanism, so that the friction pad quickly advances and retreats by the pad clearance. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals,
The description is omitted.

In the figure, reference numeral 61 denotes a caliper constituting a brake housing which is attached to each arm 1A of the carrier 1 via each sliding pin. The caliper 61 is the caliper 4 described in the first embodiment. And an inner leg portion 62, an outer claw portion 63, a bridge portion 64, and the like. However, the caliper 61 has an inner leg portion 62 having a tubular portion 62A integral with the bridge portion 64 and a bottomed tubular lid portion 6A.
2B so that it can be divided into two in the axial direction.

Reference numeral 65 denotes an electric motor provided in the cover portion 62B of the inner leg portion 62. The electric motor 65 has substantially the same configuration as the electric motor 11 described in the first embodiment, and includes a control unit and the like. , The motor shaft 65A is rotationally driven.

Reference numeral 66 denotes the inner leg 6 together with the electric motor 65.
2, a pressing force generating device serving as a pressing force generating means, which includes a feed screw 67, a piston 68, a speed reducer 69, a connecting shaft 73, a torque limiter 74, a clutch mechanism 75, and the like, which will be described later. The piston 68 advances or retracts together with the friction pad 25 when the motor shaft 65A rotates.

Reference numeral 67 denotes a cylindrical feed screw rotatably provided in the cylindrical portion 62A of the inner leg portion 62.
The base end is connected to a bevel gear 71 described later, and is driven by a speed reducer 69 integrally with the bevel gear 71 at low speed and high torque. In addition, a screw hole 67A is formed in the inner circumference of the tip side of the feed screw 67.
Is formed, and a piston 68 is screwed into the screw hole 67A.

Reference numeral 68 denotes a piston constituting a feed screw mechanism together with the feed screw 67. The piston 68 has a screw 68A formed on the outer peripheral side thereof.
7 is screwed into the screw hole 67A. And piston 6
8 is rotationally driven by a motor shaft 65A of the electric motor 65 via a connecting shaft 73 described later,
7A is displaced in the axial direction by the amount of the screw lead while relatively rotating inside 7A.

Reference numeral 69 denotes the inner leg 6 together with the electric motor 65.
2 is provided in the cover 62B of the second
As shown in FIG. 11, a sun gear 69A that rotates integrally with the motor shaft 65A, and a plurality of planetary gears 6 that mesh with the sun gear 69A and revolve around the sun gear 69A while rotating around the sun gear 69A.
9B, 69B, etc., and is configured to reduce the rotation of the motor shaft 65A and transmit it to the bevel gear 70 described later with high torque.

Reference numerals 70 and 71 denote ring-shaped bevel gears. The bevel gear 70 serves as an output shaft of a speed reducer 69 and is driven to rotate at low speed and high torque. The bevel gear 71 is integrated with the feed screw 67. 72, 72 are bevel gears 70,
The other bevel gears 71 are rotatably supported on the front end side (opening end side) of the lid 62B via a shaft 72A so that the bevel gears 70 and 71 are opposite to each other. Is to be rotated. Thereby, the bevel gears 70 to 72 are
A rotation direction reversing means for constantly rotating the feed screw 67 in the reverse direction with respect to the motor shaft 65A of the electric motor 65 is configured.

Reference numeral 73 denotes a connection shaft connected to a motor shaft 65A of the electric motor 65 via a torque limiter 74. The connection shaft 73 is formed as a spline shaft, and the front end is spline-connected to the piston 68. Thus, the connection shaft 73 transmits the rotation of the motor shaft 65A directly to the piston 68 and allows the piston 68 to relatively displace in the axial direction of the connection shaft 73.

The torque limiter 74 has substantially the same configuration as the torque limiter 55 described in the second embodiment, and always transmits the torque from the motor shaft 65A to the connecting shaft 73, and the connecting shaft 73 Allow to rotate integrally with the shaft 65A. When the torque (rotational load) of the motor shaft 65A exceeds the reference torque, the torque limiter 74
Releases the torque transmission from the motor shaft 65A to the connection shaft 73 side. Thus, the torque limiter 74 temporarily cancels the transmission of torque from the electric motor 65 to the piston 68, and prevents the rotational load of the electric motor 65 from becoming excessive.

Further, reference numeral 75 denotes a friction pad 25 on the inner side.
The clutch mechanism 75 includes a fixed clutch plate 75A fixed to the back surface of the friction pad 25 and a clutch plate 75A.
The movable clutch plate 75B is fixed to the distal end surface of the piston 68 in opposition to the clutch plate 75A and is in contact with the clutch plate 75A so as to be rotatable relative to the clutch plate 75A.
The connection between A and 75B is released, and the piston 68 is allowed to rotate integrally with the connection shaft 73 with respect to the friction pad 25.

When the inner friction pad 25 receives a brake reaction force from the disk 2 during the braking operation, the clutch plates 75A and 75B of the clutch mechanism 75 are strongly abutted (coupled) with each other, so that the friction is increased. Pad 2
5 (clutch plate 75A) with respect to the rotation of the piston 68 (clutch plate 75B).
Only the axial displacement via the feed screw 67 is permitted.

The disc brake according to the present embodiment has the above-described configuration. Next, the operation of the disc brake will be described.

First, when the driver of the vehicle depresses the brake pedal, a signal corresponding to the amount of depressing operation of the brake pedal is sent to the control unit by a pedal sensor (not shown) provided near the brake pedal. The control unit outputs the control signal corresponding to the operation amount to the electric motor 65, thereby driving the electric motor 65 to rotate at a rotation angle or rotation speed corresponding to the operation amount.

During the braking operation, the electric motor 65 rotates from the motor shaft 65A to the torque limiter 7 until the inner friction pad 25 comes into contact with the disk 2.
4. The power is transmitted directly to the piston 68 via the connecting shaft 73 and transmitted from the reduction gear 69 to the feed screw 67 via bevel gears 70, 72, 71. And the feed screw 6
7 is a low-speed rotation of the electric motor 65 via the speed reducer 69;
While being transmitted with high torque, bevel gears 70, 72, 71
As a result, the connection shaft 73 is rotated in the opposite direction.

As a result, the piston 68 which rotates in one direction integrally with the connecting shaft 73 is screwed at a high speed into the screw hole 67A of the feed screw 67 which is rotating in the opposite direction.
While being rotated along the 7A screw lead, it is sent out in the axial direction by the pad clearance C. During this time, the piston 68 is quickly displaced with a very small pressing force (reaction force) to the piston position S1, as shown by the characteristic line shown in FIG. 8 described in the second embodiment, and the time t0, t shown in FIG.
As shown in FIG. 1, the piston 68 displaces the pad clearance C of the friction pad 25 in a short time.

When the inner friction pad 25 starts to contact the disk 2, the friction pad 25 receives a brake reaction force together with the piston 6, and the brake reaction force causes the clutch plates 75A and 75B of the clutch mechanism 75 to move between the clutch plates 75A and 75B. Linked to each other. Thereby, the rotation of the piston 68 with respect to the friction pad 25 is restricted, and the connection shaft 73 and the motor shaft 6
5A, the torque limiter 74 is automatically cut off, and the rotation transmission from the electric motor 65 to the connection shaft 73 is performed by the torque limiter 5.
5 is released.

On the other hand, the feed screw 67 is driven to rotate at a low speed and a high torque by the speed reducer 69, and the piston 68 whose rotation is restricted is driven in the axial direction by the rotation of the feed screw 67. Thereby, the piston 68 strongly presses the inner friction pad 25 against one side surface of the disk 2,
The outer friction pad 25 can be pressed against the other side surface of the disc 2 by slidingly displacing the entire caliper 61, and, for example, a braking force can be reliably applied to a running vehicle via the disc 2. During this time, the piston 68 is displaced to the piston position Sa as illustrated in FIG. 8, and the pressing force (reaction force) on the disk 2 by the friction pad 25 is increased to the pressing force Fa. The time during this period is between times t1 and ta as shown by the characteristic line in FIG.

Next, when the depressing operation of the brake pedal is released in this state, the electric motor 65 is rotated in reverse by the signal from the pedal sensor. When the electric motor 65 is reversed, the brake reaction force acting on the piston 68 is initially large, and the clutch mechanism 75 maintains the connected state. Therefore, the rotation transmission from the electric motor 65 to the connecting shaft 73 is released by the torque limiter 55. Will remain.

However, since the reverse rotation of the electric motor 65 is transmitted to the feed screw 67 via the speed reducer 69 and the bevel gears 70, 72, 71, the piston 68 moves together with the friction pad 25 in the direction of retracting from the disk 2. It is driven through 67 and the pressing force of the friction pad 25 against the disk 2 can be reliably reduced. This time corresponds to the time tb, tc illustrated in FIG. 9, and the pressing force (reaction force) acting on the piston 68 is surely reduced from the level of the pressing force Fa.

When the friction pad 25 separates from the disk 2 even slightly, the brake reaction force acting on the piston 68 decreases, so that the coupling state of the clutch mechanism 75 is released, and the motor shaft 65A and the coupling shaft 73 are released. Are connected via a torque limiter 74. Thereby, the reverse rotation of the electric motor 65 is directly connected to the piston 68 via the connection shaft 73, and the feed screw 67 is connected to the speed reducer 6
9. Since the piston 68 continues to rotate in the opposite direction to the piston 68 at low speed and high torque via the bevel gears 70, 72, 71, the piston 68 can be quickly moved in the retreating direction, as shown by the characteristic line illustrated in FIG. In a short time of tc and td, the friction pad 2
5 can be retracted from the disk 2 by the pad clearance C.

Thus, in the present embodiment thus constructed, the piston 68 is disc-disposed on the inner leg portion 62 side of the caliper 61 both when the brake is operated and when the brake is released, similarly to the first embodiment. Can be advanced or retracted in a short time toward
Pad 25 between the standby position and the braking position for
Can be quickly moved by the pad clearance C shown in FIG.

In both the case of the brake operation and the case of the brake release, by rotating the feed screw 67 and the piston 68 in mutually opposite directions, the friction pad 25 between the standby position and the braking position is rotated. The movement speed of the (piston 68) can be reliably increased, 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 is improved to improve operability and safety. Can be greatly improved.

Next, FIGS. 12 to 15 show the fourth embodiment of the present invention.
The present embodiment is characterized in that a cam mechanism, an adjuster, and the like are provided in the pressing force generating means, and when the friction pad is worn while repeating the brake operation, the friction pad and the disc are moved. The gap between the feed screw member and the piston is absorbed by the cam mechanism between the feed screw member and the piston, even when the thickness of the disk fluctuates due to thermal expansion, etc. In addition, the configuration is such that the torque fluctuation can be canceled. 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 81 denotes a caliper constituting a brake housing. The caliper 81 has substantially the same configuration as the caliper 4 described in the first embodiment, and includes an inner leg portion 82 and an outer claw portion. , A bridge section (both not shown) and the like. A large-diameter sleeve sliding hole 82A is formed on the distal end side of the inner leg portion 82, and a motor housing hole (not shown) and the like are formed on the proximal end side. A small-diameter screw hole 82B is formed between the sleeve sliding hole 82A and the motor housing hole, and a screw hole 82B is formed on the peripheral wall 82C located radially outside the screw hole 82B.
Adjuster accommodation hole 82D having a bottom and surrounding the periphery of FIG.
As shown in FIG. 3, a ratchet sliding hole 82E having a rectangular cross section is formed.

Reference numeral 83 denotes an electric motor with a speed reducer provided in the motor accommodating hole of the inner leg 82.
3 is substantially the same as the electric motor 11 described in the first embodiment, but the electric motor 83 controls the output shaft 84 at low speed and high torque by a built-in speed reducer (not shown). , And is driven to rotate in the reverse direction. Here, the output shaft 84 is a rotation transmission shaft that constitutes a part of a pressing force generating device 85 described later, and a spline 84A is formed on the outer periphery on the distal end side. The output shaft 84 transmits the rotational force of the electric motor 83 to a feed screw member 88 described later via a spline 84A, and allows the feed screw member 88 to be relatively displaced in the axial direction.

Reference numeral 85 denotes the inner leg 8 together with the electric motor 83.
The pressing force generating device 85 is a pressing force generating device provided as a pressing force generating device provided in the inside 2. Composed,
When the output shaft 84 rotates, the piston 86 advances or retracts in the axial direction.

Reference numeral 86 denotes a sleeve sliding hole 8 of the inner leg 82.
The piston 86 is slidably provided in a 2A via a sleeve 91. The piston 86 is formed in a stepped cylindrical shape, and the small diameter portion 86A slides into a cylindrical portion 88B of a feed screw member 88 described later. It is inserted as much as possible. Further, a stopper 87 for preventing rotation is provided between the piston 86 and the friction pad 25 on the inner side, and relative rotation with respect to the friction pad 25 is regulated. The piston 86 is driven by the electric motor 83 via the feed screw member 88 and the cam mechanism 90, and advances and retracts in the axial direction to press the friction pad 25 against the disk 2.

Reference numeral 88 denotes a feed screw member located between the output shaft 84 and the piston 86 and disposed in the inner leg 82. The feed screw member 88 has a small diameter screw rod 88 at the base end side.
A, and the distal end side extending toward the piston 86 is a large-diameter cylindrical portion 88B formed in a bottomed cylindrical shape. Then, the feed screw member 88 has a screw rod 88A formed of the inner leg 8.
Are screwed into the two screw holes 82B via a plurality of balls 89, 89,..., And an output shaft 84 is connected to the inner peripheral side of the screw rod 88A via a spline 84A.

Reference numeral 90 denotes a cam mechanism disposed between the cylindrical portion 88B of the feed screw member 88 and the small diameter portion 86A of the piston 86. The cam mechanism 90 is, as shown in FIG.
A is formed of a plurality of spiral grooves 90A formed on the outer peripheral surface of A or the inner peripheral surface of the cylindrical portion 88B, and a plurality of balls 90B rotatably provided in each of the spiral grooves 90A. Is converted into the axial displacement of the piston 86. Then, the cam mechanism 90 is connected to the output shaft 84.
Accordingly, when the feed screw member 88 is rotated at a low speed and a high torque, the piston 86 advances and retreats in the axial direction at a high speed by the pad clearance C as shown by the characteristic line in FIG.

Reference numeral 91 denotes a cylindrical sleeve located on the outer peripheral side of the piston 86 and inserted into the sleeve sliding hole 82A of the inner leg portion 82.
It is provided in the 2A so as to be axially displaceable in a detented state, and is configured to rotatably support the cylindrical portion 88B of the feed screw member 88 from outside in the radial direction via a bearing 92. The sleeve 91 is displaced in the axial direction together with the feed screw member 88 in the sleeve sliding hole 82A of the inner leg 82.

Reference numeral 93 denotes a sleeve sliding hole 8 of the inner leg 82.
With an adjuster arranged between 2A and screw hole 82B,
The adjuster 93 rotatably supports the feed screw member 88 via a ball bearing 94, and is configured to be axially displaced together with the feed screw member 88 in the inner leg 82. The adjuster 93 is provided with upper and lower protruding teeth 93A, 93A extending toward the inside of the adjuster receiving hole 82D of the inner leg 82, and each protruding tooth 93A meshes with each ratchet 97 described later. Serrated teeth are formed.

Then, the adjuster 93 is connected to the friction pad 25.
The gap adjustment is performed to allow the feed screw member 88 to be displaced in the axial direction via the ratchet 97 in the axial direction, for example, by about one tooth of the protruding tooth portion 93A, and to keep the pad clearance C substantially constant. is there. The protruding tooth portion 93
Since the tooth row of A is set to be larger than the sum of the full stroke and the invalid stroke of the piston 86 and the clearance of the ball bearing 94, the engagement position of the adjuster 93 with respect to each ratchet 97 during a normal brake operation is changed. There is no way to advance one tooth.

Reference numeral 95 denotes a spring disposed in a contracted state between the sleeve 91 and the adjuster 93. The spring 95 constantly urges each protruding tooth portion 93A of the adjuster 93 toward the inside of the adjuster housing hole 82D. , Each protruding tooth portion 93A
And the respective ratchets 97 in good engagement.

Reference numeral 96 denotes an adjuster 93 in the inner leg 82.
As shown in FIG. 13, the ratchet mechanism 96 is provided in a ratchet sliding hole 82E of the inner leg portion 82, and each protruding tooth portion 93 of the adjuster 93 is provided.
A pair of ratchets 97, 9 meshed from both upper and lower sides
7 and each ratchet 97 is disposed in a contracted state between the inner leg portion 82 and each ratchet 97 is attached to each protruding tooth portion 9.
It is generally constituted by a plurality of biasing springs 98 constantly biased toward the 3A side. The ratchet mechanism 96 is configured to allow the ratchet 97 to displace the adjuster 93 together with the feed screw member 88 in the forward direction toward the friction pad 25, and to restrict the adjuster 93 from being displaced in the reverse direction in the backward direction. Has become.

Further, a plurality of insertion holes 97A, 97A,
Are formed, and a tapered guide surface 97B is formed at an end of each insertion hole 97A. On the other hand, the inner leg 8
2 are formed with long guide holes 99, 99,... Through which the adjustment rods 100 are inserted, and the end of each guide hole 99 is located at a position opposite to the guide surface 97B of each insertion hole 97A. It is a bottom engagement hole 99A.

Further, reference numerals 100, 100,... Are adjustment rods inserted into the respective guide holes 99 of the inner leg portion 82. As shown in FIG. It is arranged at a position slightly away from the hole 97A, and allows each ratchet 97 to mesh with each protruding tooth 93A of the adjuster 93. Then, for example, when the friction pad 25 is replaced, each adjustment rod 1
00 is pushed in the axial direction toward each insertion hole 97A of each ratchet 97, and is held in an engagement state with each engagement hole 99A. At this time, each ratchet 97 is pressed radially outward on each distal end side of each adjustment rod 100 via each guide surface 97B, and each urging spring 9 is moved in the direction of arrow D shown in FIG.
8 is displaced.

As a result, each ratchet 97 is separated from each protruding tooth 93A of the adjuster 93 in the direction indicated by the arrow D, and the meshing state with each protruding tooth 93A is released. For this reason, even if the adjuster 93 is gradually pushed out to the friction pad 25 side in accordance with the wear of the friction pad 25,
With each adjusting rod 100, each ratchet 97 and adjuster 9
By disengaging the adjuster 93, the projecting teeth 93A of the adjuster 93 are pushed back into the adjuster housing holes 82D by the spring 95, and the projecting teeth 93A are released.
And the ratchet 97 can be adjusted easily.

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

First, when the driver of the vehicle depresses the brake pedal, a signal corresponding to the operation amount of the brake pedal is sent to the control unit by a pedal sensor (not shown) provided near the brake pedal. Is output. Then, the control unit outputs a control signal corresponding to the operation amount to the electric motor 83, and drives the electric motor 83 to rotate at a rotation angle or rotation speed corresponding to the operation amount.

Here, the rotation of the electric motor 83 is reduced by the built-in speed reducer while the feed screw member 88 is rotated from the output shaft 84.
The cam mechanism 90 converts the rotation of the feed screw member 88 into an axial displacement of the piston 86, and shortens the piston 86 until the inner friction pad 25 contacts the disk 2. Advance in time. This period corresponds to the pad clearance C shown in FIG. 15, and since the brake reaction force does not substantially act on the piston 86, the cam mechanism 90 causes the small rotation of the feed screw member 88 to rotate the relatively large shaft of the piston 86. This is converted into directional displacement.

Then, the friction pad 25 on the inner side is moved together with the piston 86 by the amount of the pad clearance C for the disk 2.
When it starts moving toward the disc 2 and starts to contact the disk 2, the braking region shown in FIG. 15 is reached, and the braking reaction force acting on the piston 86 gradually increases, so that the operation of the cam mechanism 90 is substantially stopped. However, since the rotation of the output shaft 84 having a high torque at a low speed is transmitted to the feed screw member 88 via the spline 84A, the feed screw member 88 is pushed in the axial direction while being rotated by the screw lead of the screw hole 82B. The inner friction pad 25 can be strongly pressed against one side of the disk 2 by the piston 86, and the outer friction pad 25 can be pressed against the other side of the disk 2 by slidingly displacing the entire caliper 31. The braking force can be reliably applied to the vehicle that is running through the disk 2.

Next, when the depression operation of the brake pedal is released in this state, the electric motor 83 is rotated in reverse by the signal from the pedal sensor. When the electric motor 83 is rotated in the reverse direction, since the brake reaction force from the piston 86 is initially large, the operation of the cam mechanism 90 is substantially stopped, and the reverse rotation of the output shaft 84 is performed via the spline 84A. To the feed screw member 88. As a result, the feed screw member 88 is retracted in the axial direction by the amount of the screw lead, and the piston 86 can be driven in the direction of retracting from the disk 2 together with the friction pad 25, so that the pressing force of the friction pad 25 on the disk 2 is reliably reduced. be able to.

When the friction pad 25 is slightly separated from the disk 2, the cam mechanism 90 is actuated due to a decrease in the brake reaction force, and the cam mechanism 90 causes the small rotation of the feed screw member 88 to cause the large displacement of the piston 86. The displacement can be converted into the axial displacement, and the friction pad 25 can be quickly retracted from the disk 2 by the pad clearance C.

If the friction pad 25 becomes worn during the repetition of the brake operation as described above, the brake pedal is fully depressed, for example, when the vehicle is stopped or the engine is started, so that the piston 86 is fully stroked. The ratchet mechanism 96 allows the adjuster 93 to be displaced toward the friction pad 25 together with the feed screw member 88. At this time, the gap between the friction pad 25 and the disk 2 is automatically adjusted by the adjuster 93. And the pad clearance C can be maintained at a substantially constant size.

When the wear amount of the friction pad 25 gradually increases and the time for replacing the friction pad 25 has been reached, each adjusting rod 100 is inserted into each of the insertion holes 97A of the ratchet 97.
By pushing inward in the axial direction, each ratchet 9
7 can be pressed radially outward on the distal end side of each adjusting rod 100 via each guide surface 97B, and each ratchet 97 can be separated from each protruding tooth 93A of the adjuster 93 in the arrow direction D, and each protruding tooth 93A can be separated. Can be easily released, and in this state, if the tip side of each adjustment rod 100 is engaged with each engagement hole 99A, each ratchet 9
7 can be held in the disengaged state, and after the friction pad 25 is replaced, each protruding tooth 93A of the adjuster 93 and each ratchet 9
7 can be easily adjusted.

On the other hand, even if the thickness of the disk 2 fluctuates due to thermal expansion or the like during the repetition of the brake operation, the cam mechanism 90 provided between the feed screw member 88 and the piston 86 is provided in each spiral groove 90A. On the other hand, since the balls 90B are engaged so as to roll reversibly in the forward and backward directions, the fluctuation in the thickness of the disk 2 can be absorbed, the fluctuation in torque can be canceled, and the braking force is released. At times, the friction pad 25 can be reliably separated from the disk 2.

Thus, in the present embodiment having the above-described structure, the piston 86 is disc-disposed on the inner leg portion 82 side of the caliper 81 both when the brake is operated and when the brake is released, similarly to the first embodiment. Can be advanced or retracted in a short time toward
Pad 25 between the standby position and the braking position for
Can be quickly moved by the pad clearance C shown in FIG.

In both the case of the brake operation and the case of the brake release, the moving speed of the friction pad 25 (piston 86) between the standby position and the braking position can be reliably increased, and the response of the brake operation can be improved. In addition to improving the operability, the friction pad 25 can be returned to the early stage even when the brake operation is released, and the responsiveness can be increased, and the operability and safety can be greatly improved.

In each of the above embodiments, the case where the electric 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. The present invention may be applied to a brake, or may be applied to other electric brake devices.

[0145]

As described in detail above, according to the first aspect of the present invention, the pressing force generating means for pressing the friction member against the rotating member by the rotation of the electric motor includes a feed screw mechanism having a piston, Since it is constituted by the reduction gear, the centrifugal clutch and the rotation transmission switching means, the centrifugal clutch can be operated and the feed screw mechanism can be driven at high speed while the rotational load acting on the electric motor is small, and the friction member is rotated from the standby position by the piston. It can be quickly displaced to the braking position in contact with the member. In both the case of the brake operation and the time of the brake release, the moving speed of the friction member between the standby position and the braking position can be reliably increased, and the responsiveness of the brake operation can be improved. The friction member can be returned early even at the time of releasing, and the responsiveness can be increased, and the operability and safety can be greatly improved.

Also, in the present invention, the pressing force generating means is constituted by the feed screw mechanism, the speed reducer, the cam mechanism and the torque limiter, so that the torque (rotational load) acting on the electric motor is reduced by the torque limiter. While the torque is lower than the reference torque, the piston of the feed screw mechanism can be largely driven in the axial direction by the cam mechanism, and the piston can quickly displace the friction member from the standby position to the braking position in contact with the rotating member. In addition, even when the brake operation is released, the friction member can be returned to the early stage, and the responsiveness can be improved, and the operability and safety can be greatly improved.

Further, in the present invention, the pressing force generating means is constituted by the feed screw mechanism, the speed reducer connecting shaft, the torque limiter and the clutch mechanism, so that the torque acting on the electric motor is equal to the reference torque of the torque limiter. When the rotation speed is lower than that, the rotation of the electric motor can be transmitted to the piston of the feed screw mechanism via the torque limiter and the connection shaft, and the piston can be largely driven in the axial direction while being rotated together with the connection shaft via the clutch mechanism. As a result, the friction member can be quickly displaced from the standby position to the braking position, and the friction member can be returned quickly even when the brake operation is released, so that the responsiveness can be improved and the operability and safety can be greatly improved.

According to the fourth aspect of the present invention, the pressing force generating means is constituted by the piston, the feed screw member, the rotation transmitting shaft, the cam mechanism, the sleeve, the adjuster, and the ratchet mechanism. Until the reaction force is received, the rotation of the electric motor is transmitted to the cam mechanism via the rotation transmitting shaft and the feed screw member, and the piston can be largely driven in the axial direction by the cam mechanism. It can be quickly displaced between the positions.

If the friction member becomes worn while repeating the braking operation, the ratchet mechanism allows the adjuster to be displaced toward the friction member together with the feed screw member, and the gap between the friction member and the rotating member is reduced. Can be automatically adjusted by the adjuster. Further, even when the thickness of the rotating member fluctuates due to thermal expansion or the like, the thickness of the rotating member can be absorbed by the cam mechanism provided between the feed screw member and the piston, thereby canceling the torque fluctuation and the like. Can be.

[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 shows the specific configuration of the centrifugal clutch as indicated by an arrow in FIG.
It is the expanded sectional view seen from the III-III direction.

FIG. 4 is a longitudinal sectional view showing a disk brake according to a second embodiment of the present invention at the same position as in FIG. 2;

FIG. 5 is a vertical sectional view showing the operation state of the cam mechanism at the same position as in FIG. 4;

FIG. 6 is an enlarged view of a main part of FIG. 4, showing a main part of the cam mechanism in an enlarged manner.

FIG. 7 is an enlarged view of a main part of FIG. 5, showing a state in which a cam mechanism is operated.

FIG. 8 is a characteristic diagram showing a relationship between a piston position and a pressing force.

FIG. 9 is a characteristic diagram showing a change over time of a piston position and a pressing force.

FIG. 10 is a longitudinal sectional view showing a disk brake according to a third embodiment of the present invention at a position similar to FIG. 2;

FIG. 11 is an enlarged view of a main part of FIG. 10 showing a configuration of a speed reducer.

FIG. 12 is a longitudinal sectional view showing a disc brake according to a fourth embodiment of the present invention.

FIG. 13 is an enlarged cross-sectional view showing the adjuster, the ratchet mechanism, and the like, as viewed from the direction indicated by arrows XIII-XIII in FIG. 12;

FIG. 14 is a partial cross-sectional view of the same position as in FIG. 12 showing a state where the cam mechanism is operated.

FIG. 15 is a characteristic diagram illustrating a relationship between a rotation angle of a feed screw member and a displacement amount of a piston.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Carrier 12 Disk (rotating member) 4,31,61,81 Caliper (brake housing) 5,32,62,82 Inner leg part 11,37,65,83 Electric motor 12,38,66,85 Pressing force generator (Pressing force generating means) 13, 39, 68, 86 Piston 14, 40 Screw rod (feed screw mechanism) 18, 41, 69 Reducer 15 Drum 23 Centrifugal clutch 24 One-way clutch (Rotation transmission switching means) 25 Friction pad (Friction) 42, 90 Cam mechanism 48 Cam 55, 74 Torque limiter 67 Feed screw (feed screw mechanism) 70, 71, 72 Bevel gear 73 Connecting shaft 75 Clutch mechanism 88 Feed screw member 91 Sleeve 93 Adjuster 96 Ratchet mechanism 97 Ratchet 100 Adjustment rod

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tadaaki Nakamura 1-6-3 Fujimi, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Tokiko Corporation

Claims (4)

[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 a feed screw mechanism provided between the feed screw mechanism and the electric motor to reduce the rotation of the electric motor to reduce the feed screw. A speed reducer for transmitting to a mechanism, provided between the electric motor and the feed screw mechanism, and actuated when the rotation speed of the electric motor reaches a predetermined set speed to rotate the electric motor. A centrifugal clutch that transmits to the feed screw mechanism and is in a standby state until the set speed is reached to cancel rotation transmission to the feed screw mechanism, between the electric motor and the speed reducer. A rotation transmission for transmitting a rotational force from the electric motor to the speed reducer when the electric motor rotates in one direction, and transmitting a rotational force from the speed reducer to the electric motor when the electric motor rotates in the opposite direction. An electric brake device comprising: a switching unit. 2. A brake housing, an electric motor provided in the brake housing, and 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 a feed screw mechanism provided between the feed screw mechanism and the electric motor to reduce the rotation of the electric motor to reduce the feed screw. A speed reducer for transmitting to a mechanism; a cam mechanism provided between the electric motor and the feed screw mechanism for converting rotation of the electric motor to axially drive a piston of the feed screw mechanism; The torque of the electric motor is transmitted to the cam mechanism until the torque of the electric motor reaches a predetermined reference torque, and the torque exceeds the reference torque. Electric brake apparatus characterized by being configured and a torque limiter to release the transmission of torque to the cam mechanism to come. 3. 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 for converting the displacement into a displacement; a speed reducer provided between the feed screw mechanism and the electric motor, for reducing the rotation of the electric motor and transmitting the rotation to the feed screw mechanism; and the rotation of the electric motor. To the piston of the feed screw mechanism, the coupling shaft being connected to the piston to allow relative displacement of the piston in the axial direction; and a coupling shaft provided between the coupling shaft and the electric motor. Until the motor reaches a predetermined reference torque, the torque of the electric motor is transmitted to the connection shaft, and when the reference torque is exceeded, the torque transmission for releasing the torque to the connection shaft is released. , A piston provided between the piston of the feed screw mechanism and the friction member, always allowing rotation of the piston via the connection shaft, and a brake reaction force from the friction member toward the piston side during a brake operation. And a clutch mechanism for restricting the rotation of the piston by the brake reaction force when is operated. 4. 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 that is pressed toward a rotating member by the pressing force generating unit and applies a braking force to the rotating member; wherein the pressing force generating unit presses the friction member in an axial direction. A piston abutting on the friction member and being restricted from rotating with respect to the friction member; a feed screw member having a proximal end screwed into the brake housing and a distal end extending toward the piston; A rotation transmission shaft provided between the feed screw member and the electric motor, transmitting rotation of the electric motor to the feed screw member, and allowing the feed screw member to be relatively displaced in the axial direction; A cam mechanism for driving a piston in the axial direction via the feed screw member by the rotation of the electric motor; and a slidably provided in the brake housing. A sleeve rotatably supporting the distal end side of the feed screw member, a rotatable support for the feed screw member in the brake housing, and an axial direction together with the feed screw member for adjusting a wear amount of the friction member. An adjuster that is relatively displaced, provided between the adjuster and the brake housing,
A ratchet mechanism for allowing the adjuster to move toward the friction member together with the feed screw member, and for restricting the adjuster from displacing in the opposite direction.