KR20170068799A

KR20170068799A - Electric brake with cogging torque reducing device

Info

Publication number: KR20170068799A
Application number: KR1020150175717A
Authority: KR
Inventors: 이중희; 정종윤; 현동윤
Original assignee: 현대자동차주식회사
Priority date: 2015-12-10
Filing date: 2015-12-10
Publication date: 2017-06-20
Also published as: KR101876006B1

Abstract

The present invention relates to an electric brake having a device capable of canceling a motor cogging torque using a spring force in the event of a power failure.
The present invention implements an electric brake including a device capable of providing a reverse torque using a spring to cancel a cogging torque of the motor in the event of a power failure so that the braking force can be released at the time of power failure, It is possible to shorten the braking distance by preventing the wheel from being locked when the ABS is operated, such that the braking force can be quickly released by the energy stored in the spring, while the clutch structure capable of causing slip by increasing the spring reaction force torque The present invention provides an electric brake having a cogging torque reduction device that allows an appropriate correction to be made corresponding to brake pad wear.

Description

ELECTRIC BRAKE WITH COGGING TORQUE REDUCING DEVICE WITH Cogging Torque Reduction Device

The present invention relates to an electric brake having a cogging torque reduction device, and more particularly, to an electric brake having a device capable of canceling a motor cogging torque using a spring force in the event of a power failure.

In general, electric brakes can improve braking safety performance because they can be controlled quickly and precisely with respect to the hydraulic brake, which is essential for brake-by-wire.

These electric brakes generate the braking force by driving the motor and mechanically transmitting the rotational force.

On the other hand, a motor using a permanent magnet and an iron core has a cogging torque, and this caulking torque acts as a resistance force such as a frictional force, which interferes with the motion of the motor.

Therefore, the braking force can be maintained in a state in which the braking force is not sufficiently released due to the cogging torque of the motor when the power source fails.

As a result, if such a situation occurs during driving, a braking operation may occur and a dangerous situation such as a vehicle spin may result.

As an example, Korean Patent Laid-Open Publication No. 10-2012-0025140 discloses an " electric brake apparatus ".

When the electric motor rotational force is transmitted to the screw through the reduction gear, the rotational force is converted into a linear force by the screw mechanism, and the piston is pressed to generate a clamping force. By the clamping force at this time, The pad is pressed against the brake disc to generate the braking force.

In this "electric brake apparatus", when a power failure occurs during braking, a torque for rotating the motor in the reverse direction is generated by the caliper body clamping force, but this reverse torque is canceled by the motor cogging torque so that the braking force may not be sufficiently released, This can result in a car spin causing a dangerous situation.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above problems, and it is an object of the present invention to provide an electric brake including a device capable of providing a reverse torque by using a spring to cancel a cogging torque of a motor in the event of a power failure, Which is capable of quickly releasing the braking force by the energy stored in the spring even in normal operation, and an electric brake having a cogging torque reduction device that can shorten the braking distance by preventing the wheel from being locked during ABS operation The purpose is to provide.

It is another object of the present invention to provide an electric brake having a cogging torque reduction device that can appropriately correct a brake pad wear by applying a clutch structure capable of causing slip while a spring reaction force torque is increased when a motor rotation angle is increased, .

To achieve the above object, an electric brake having a cogging torque reduction device provided by the present invention has the following features.

An example of an electric brake having the cogging torque reduction device is a structure including an electric brake that generates a braking force by using a power of a motor and a screw mechanism. The electric brake includes a structure in which both ends are fixed between an output side of the motor and a spring holder And may include a torsion spring that stores elastic energy as it is deformed (compressed) during normal operation of the motor and provides a reverse torque to the motor output while being restored upon reverse operation of the motor.

The torsion spring may be installed in a structure in which one end of the torsion spring is accommodated inside the spring holder and the other end is fixed to the slip plate mounted around the gear shaft side of the reduction gear rotated by the motor.

The rotating plate may be coupled to a slip plate and a clutch structure elastically supported by a compression spring, and may be rotated together with the clutch plate. So that a slip can occur between the two.

Here, the clutch structure between the rotating plate and the slip plate may have a structure in which they are engaged with each other through serrations formed on the surfaces facing each other, or they may be in contact with each other through frictional portions formed on the surfaces facing each other.

Another example of the electric brake having the cogging torque reduction device is a structure including an electric brake that generates a braking force by using a power of a motor and a screw mechanism. The electric brake includes a gear shaft of a reduction gear that decelerates the output of the motor The other end of the torsion / compression spring having one end fixed to the spring holder is fixed to the slip plate, and the torsion / compression spring elastically biases the slip plate toward the slip plate, In addition to the support, it is possible to store the elastic energy while being compressed in the forward direction of the motor and to provide the reverse torque to the motor output side while being restored in the reverse direction of the motor operation.

In another example of the electric brake having such a cogging torque reducing device, the clutch structure between the rotating plate and the slip plate may have a structure in which they are engaged with each other through toothed portions formed on the surfaces facing each other, And the other end of the contact portion is in contact with the contact portion.

The present invention has the following advantages over conventional electric brakes.

First, when the electric power supply to the electric brake fails, the braking force can be quickly released and the residual braking force can be removed, thereby improving the safety by preventing the risk of vehicle spin.

Second, it is possible to shorten the braking distance by preventing the sudden decrease of the wheel circumference by accelerating the braking force release in the ABS operation.

Thirdly, when the motor rotation angle becomes large when the brake pad is worn, the slip occurs when the torsion spring reaction force torque is larger than the slip support torque due to the clutch and the compression spring between the rotating plate and the slip plate.

1 is a cross-sectional view showing an overall structure of an electric brake having a cogging torque reduction device according to an embodiment of the present invention;
2 is a perspective view showing an example of a cogging torque reduction apparatus in an electric brake having a cogging torque reduction apparatus according to an embodiment of the present invention.
3 is a perspective view showing another example of the cogging torque reduction device in the electric brake having the cogging torque reduction device according to the embodiment of the present invention.
4 is a perspective view showing still another example of the cogging torque reduction device in the electric brake having the cogging torque reduction device according to the embodiment of the present invention.
5 is a graph showing a cogging torque reduction effect in an electric brake having a cogging torque reduction device according to an embodiment of the present invention

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a sectional view showing the entire structure of an electric brake having a cogging torque reduction device according to an embodiment of the present invention.

As shown in FIG. 1, the electric brake having the caulking torque reducing device is constructed so as to cancel the cogging torque of the motor in a manner of providing a reverse torque by using a torsion spring.

To this end, the electric brake having the cogging torque reduction device has a basic structure of a structure and an operation mode of a general electric brake.

For example, the electric brake having the cogging torque reduction device includes a caliper 25 having a disk 27 and brake pads 26 on both sides, a housing 11 installed on one side of the caliper 25, A motor 10 mounted on the housing 11 and a gear train meshed with the motor gear 20, a reduction gear 14, a spindle gear 21 ).

In addition, the electric brake having the cogging torque reduction device is installed inside the caliper 25 and presses the brake pad 26 by using a screw mechanism. The electric brake is connected to the spindle gear 21, And a nut 21 which is coupled to the spindle 23 in a screw-rotatable manner to press the brake pads 26 in a forward and backward linear motion.

Accordingly, the electric brake with the cogging torque reduction device basically operates in the forward direction of the motor 10 by rotating the motor gear 20, rotating the reduction gear 14, rotating the spindle gear 21, The braking force of the type in which the rotation of the spindle 23, the linear movement of the nut 24, and the brake pad 26 are continued to the pressing of the disc 27 can be generated.

Of course, the braking force can be released during the reverse operation of the motor 10. [

In particular, the electric brake with the cogging torque reduction device includes a torsion spring 13 as a means capable of canceling the motor cogging torque in normal operation as well as power failure.

2 and 3, the torsion spring 13 is installed at both ends between the output side of the motor 10 and the spring holder 12, When the motor is operated in the forward direction, it stores the elastic energy while being compressed. When the motor is operated in the reverse direction, it is restored and serves to provide the reverse torque to the motor output side.

The torsion spring 13 may be mounted on the inner side of the housing 11, for example, at a side of the reduction gear 14 facing the axial line of the reduction gear 14, And a torsion spring 13 is accommodated inside the spring holder 12. The spring holder 12 is installed inside the spring holder 12,

At this time, the torsion spring 13 is disposed in such a manner as to concentrically surround the periphery (the boss portion and the compression spring periphery portion) of the gear shaft 15, and one end thereof is fixed to the wall surface of the spring holder 12 And the other end thereof is fixed to one side of the slip plate 17, which will be described later.

For example, since the other end of the torsion spring 13 is bent, the bent end of the torsion spring 13 is caught by the formed spring holding groove 30 at the outer peripheral portion of the slip plate 17 , And the other end of the torsion spring 13 can be fixed.

Here, the torsion spring 13 installed in the spring holder 12 can have a substantially coaxial structure with the gear shaft 15 of the reduction gear 14.

The electric brake with the cogging torque reduction device includes a rotary plate 16 as a means for winding and releasing the torsion spring 13 together with the slip plate 17.

The rotary plate 16 is formed in a disc shape having a boss portion 32 and the rotary plate 16 is fitted to the gear shaft 15 of the reduction gear 14 through the boss portion 32 to be coupled thereto.

Accordingly, the rotary plate 16 can be rotated together with the gear shaft 15 during the reduction gear rotation.

The electric brake with the cogging torque reduction device also includes a slip plate 17 as a means for correcting the pad wear.

The slip plate 17 is in the form of a disk and is fitted in the boss portion 32 of the rotary plate 16 coupled to the gear shaft 15 of the reduction gear 14 through the center thereof and is freely rotatable, It is possible to have a coupling relationship capable of rotating together with the rotary plate 16 or a slip relationship capable of causing slip by the clutch structure described later.

A compression spring 18 surrounding the periphery of the rotary plate boss portion 32 is disposed at the rear side of the slip plate 17. The compression spring 18 at this time is fixed to the washer 32, And the other end of the slip plate 17 elastically supports the rear surface of the slip plate 17. [0033]

Accordingly, the slip plate 17 can be closely attached to the rotary plate 16 by the pushing force of the compression spring 18, and can be rotated together with the rotary plate 16 via the clutch structure.

Particularly, the slip plate 17 is elastically supported by the compression spring 18 and is coupled to the rotary plate 16 in a clutch structure so that the slip plate 17 can be rotated together or slip together.

For example, the clutch structure between the rotary plate 16 and the slip plate 17 may be configured to be engaged with the toothed portions 19a and 19b formed on the surfaces facing each other, The rotary plate 16 and the slip plate 17 can be rotated together or the rotary plate 16 and the slip plate 17 can be rotated in accordance with the force relationship between the compression spring 18 and the torsion spring 13. [ (Fig. 2).

As another example, the clutch structure between the rotary plate 16 and the slip plate 17 may be configured to come in contact with each other through the frictional portions 28a and 28b formed on the surfaces facing each other, and the frictional portions 28a The rotary plate 16 and the slip plate 17 can be rotated together using the coupling structure between the compression spring 18 and the torsion spring 13, (Fig. 3).

Since the clutch engagement force by the compression spring 18 is generated between the rotary plate 16 and the slip plate 17 and one end of the torsion spring 13 is engaged with the slip plate 17, The gear rotational motion can rotate the torsion spring 13 via the clutch as a transfer medium to store energy.

That is, since the rotary plate 16 and the slip plate 17 are engaged with the clutch structure via the compression spring force and the torsion spring 13 is connected to one side of the slip plate 16, When the plate 17 is rotated in the forward direction (for example, counterclockwise), the torsion spring 13 can be compressed while being rolled. On the other hand, when the rotary plate 16 and the slip plate 17 are rotated in opposite directions So that the wound torsion spring 13 is released and can be restored to the initial state.

When the brake pad wears up, when the force of the torsion spring 13 overcomes the clutch engagement force due to the pressing of the compression spring 18 in accordance with the rotation of the gear during braking, the clutch part slips, The rotating disk 16 rotating together is rotated by an amount corresponding to the pad wear, so that the brake pad wear can be corrected.

4 is a perspective view showing still another example of a cogging torque reduction apparatus in an electric brake having a cogging torque reduction apparatus according to an embodiment of the present invention.

As shown in FIG. 4, here, a structure is shown in which a clutch engaging force is generated and a spring energy is stored by using a torsion / compression spring 29 that is a combination of a torsion spring and a compression spring.

A rotary plate 16 and a slip plate 17 which are coupled to each other by a clutch structure to cause rotation or slip on the gear shaft 15 of the reduction gear 14 serving to decelerate the output of the motor 10, ).

The rotary plate 16 and the slip plate 17 are engaged with each other by the clutch structure and can be rotated together or slip together.

For example, the rotary plate 16 and the slip plate 17 can be engaged through the toothed portions 19a and 19b formed on the surfaces facing each other, and the binding structure between the toothed portions 19a and 19b at this time The slip plate 17 and the rotary plate 16 can be rotated together or if the force of the torsion spring 13 is greater than the clutch engagement force of the compression spring 18,

Although not shown, the rotary plate 16 and the slip plate 17 can be engaged while being in contact with each other through a friction portion formed on a surface facing each other, and the rotary plate 16 and the slip plate 17 can be rotated together Slip may occur.

The other end of the torsion / compression spring 29 whose one end is fixed to the spring holder 12 is fixed to the slip plate 17 on the slip plate 17.

Accordingly, the torsion / compression spring 29 functions to generate the clutch engaging force by pressing the slip plate 17 toward the rotary plate 16, as well as to store the elastic energy while being compressed during forward operation of the motor, And serves to provide a reverse torque to the motor output side while being restored.

5 is a graph showing a cogging torque reduction effect in an electric brake having a cogging torque reduction device according to an embodiment of the present invention, and shows a spring torque state at the time of pressurization (braking).

That is, when the motor 10 rotates in the forward direction, the spindle 23 connected to the gear flow rotates in the forward direction. When the nut 24 is linearly moved, the brake pad 26 To generate a braking force.

At this time, as the motor 10 rotates in the forward direction, the rotary plate 16 connected to the gear shaft 15 rotates together with the gear shaft 15, and the slip plate 17 connected to the rotary plate 16 in a clutch structure And rotate together.

When the rotary plate 16 and the slip plate 17 are rotated, the torsion spring 13 connected thereto is compressed and elastic energy is stored.

When the motor 10 rotates in the reverse direction during the decompression for releasing the brake, the spindle 23 rotates in the opposite direction to release the braking force as opposed to the pressurization.

At this time, the rotary plate 16 and the slip plate 17 are also rotated in the reverse direction, and the compressed torsion spring 13 is returned when the pressure is applied, thereby providing an inverse torque to the gear shaft 15 to accelerate the release of the braking force.

When the rotation angle of the motor 10 is increased when the brake pads 26 are worn, the slip occurs when the torsion spring reaction force is greater than the clutch engagement force of the compression spring 18, Correction by wear is achieved.

That is, when the motor rotation angle becomes larger, the slip occurs when the torsion spring reaction force torque is larger than the slip support torque by the clutches of the rotary plate 16 and the slip plate 17 and the compression spring 18, So that correction for the pad wear can be performed.

In particular, in the event of a power failure, if the electric brake power source fails during braking, the torsion spring 13, which was compressed at the time of pressurization, provides a reverse torque to the gear shaft 15, that is, the torsion spring torque is transmitted to the gear shaft torque , The braking force is canceled by canceling the cogging torque and rotating the gear in the reverse direction.

As described above, according to the present invention, by embodying the electric brake including the device for providing the reverse torque by the spring force, it is possible to cancel the motor cogging torque at the time of power failure, assist the quick release of the braking force It is possible to solve problems that may occur due to a power failure and to shorten the braking distance even during normal braking.

10: Motor
11: Housing
12: Spring holder
13: Torsion spring
14: Reduction gear
15: Gear shaft
16: Spindle
17: slip plate
18: Compression spring
19a, 19b:
20: Motor gear
21: Spindle gear
22: spring rod
23: Spindle
24: Nut
25: caliper
26: Brake pad
27: Disc
28a, 28b:
29: Torsion / compression spring
30: Spring Hook Home
31: Spring fixing end
32: boss part

Claims

And an electric brake for generating a braking force using the power of the motor (10) and a screw mechanism,
A torsion spring (not shown) which is installed at a fixed position between the output side of the motor 10 and the spring holder 12 so as to store the elastic energy while being deformed when the motor is operated in the normal direction and to provide a reverse torque to the motor output side 13). &Lt; / RTI >

The method according to claim 1,
The torsion spring 13 is mounted on the periphery of the gear shaft 15 of the reduction gear 14 rotated by the motor 10 while one end of the torsion spring 13 is accommodated inside the spring holder 12, 17) is fixed to one end of the cogging torque reduction device.

The method according to claim 1,
And a rotary plate 16 mounted on a gear shaft 15 of a reduction gear 14 rotated by the motor 10. The rotary plate 16 is supported by a compression spring 18, (17) are coupled to each other by a clutch structure so that they can rotate together or slip between each other.

The method of claim 3,
Wherein the clutch structure between the rotating plate (16) and the slip plate (17) is configured to engage through teeth (19a, 19b) formed on opposite surfaces of the rotating plate (16) and the slip plate (17).

The method of claim 3,
Wherein the clutch structure between the rotating plate (16) and the slip plate (17) is in contact with the friction surfaces (28a, 28b) formed on the surfaces facing each other.

And an electric brake for generating a braking force using the power of the motor (10) and a screw mechanism,
A rotary plate 16 and a slip plate 17 which are coupled together by a clutch structure to cause rotation or slip together are mounted on a gear shaft 15 of a reduction gear 14 that decelerates the output of the motor 10, The other end of the torsion / compression spring 29 whose one end is fixed to the holder 12 is fixed to the slip plate 17. The torsion / compression spring 29 elastically supports the slip plate 17, Wherein the motor is configured to store elastic energy while being compressed during forward operation and to provide a reverse torque to the motor output while being restored upon reverse operation of the motor.

The method of claim 6,
Wherein the clutch structure between the rotating plate (16) and the slip plate (17) is configured to engage through teeth (19a, 19b) formed on opposite surfaces of the rotating plate (16) and the slip plate (17).

The method of claim 6,
Wherein the clutch structure between the rotating plate (16) and the slip plate (17) is in contact with the friction surfaces (28a, 28b) formed on the surfaces facing each other.