KR20210001765A - Electro-mechanical brake - Google Patents

Abstract

Disclosed is an electromechanical brake that not only improves controllability but also improves self release performance. According to an aspect of the present invention, provided is an electromechanical brake comprising: a caliper housing provided with a cylinder in which a piston is installed to advance and retreat to press a pad plate; a power conversion unit including a spindle that is installed in the cylinder and rotates by receiving rotational force from an actuator that generates a braking force, and a nut coupled to the spindle to convert a rotational motion into a linear motion to move the piston forward and backward; and a clutch unit installed on the spindle to rotate together with the spindle in a no-load section of the power conversion unit when driven in a direction to generate a braking force, and to store an elastic force in a direction to release the braking force in a load section.

Description

Electromechanical brake {ELECTRO-MECHANICAL BRAKE}

The present invention relates to an electromechanical disc brake, and more particularly, to an electromechanical disc brake that implements braking by converting a rotational motion into a linear motion.

In general, an electro-mechanical brake is a next-generation brake concept that senses the driver's braking will and then adjusts the braking pressure of the front and rear wheels using an electric motor such as a motor.

Electromechanical brakes are all intelligent, ranging from general braking functions, ABS (anti-lock brake system), ESC (electronic stability control), VDC (vehicle dynamic control) functions, as well as automatic braking functions required by intelligent constant speed driving systems in the future. It enables the braking role.

Such an electromechanical brake converts rotational force through a motor and a reducer into linear motion to generate an appropriate clamping pressure in the caliper, and performs a service brake and parking brake function through the clamping pressure. Here, the electromechanical brake uses a ball screw or a ball in ramp (BIR), or a ball screw type nut, with a linear moving part that converts rotational motion into linear motion in order to improve the release performance. It was intended to improve performance by adding an elastic body (spring).

However, when the ball-in lamp is installed, there is a limitation that the length of the linear moving part must be lengthened in the longitudinal direction, and there is a problem that a package fixing the spring is not excellent when additional springs are installed.

The electromechanical brake according to an exemplary embodiment of the present invention not only improves control performance, but also improves self-recovery performance.

According to an aspect of the present invention, a caliper housing provided with a cylinder in which a piston is installed to move forward and backward to pressurize a pad plate; A power conversion unit including a spindle installed in the cylinder and configured to rotate by receiving a rotational force from an actuator generating a braking force, and a nut coupled to the spindle to convert a rotational motion into a linear motion to move the piston forward and backward; And a clutch unit installed on the spindle and rotating together with the spindle in a no-load section of the power conversion unit when driving in a direction generating braking force, and storing an elastic force in a direction releasing the braking force in the load section. Brakes can be provided.

In addition, the clutch unit, the front portion is opened so as to form an inner receiving space, rotatably seated on a rear wall of the cylinder, and a cylindrical outer clutch having a hollow formed in the rear portion so that the spindle penetrates; An inner clutch installed on the spindle so as to rotate together with the spindle and disposed in the receiving space so as to contact the inner circumferential surface of the outer clutch; And a mechanical energy storage unit provided between the outer clutch and the inner clutch to store elastic force when the inner clutch rotates relative to the outer clutch.

In addition, the mechanical energy storage unit, the elastic member inserted into the receiving groove formed at regular intervals along the inner peripheral surface of the outer clutch; And a pressing member that is elastically supported by the elastic member, compresses the elastic member by pressing, and is inserted into the receiving groove.

In addition, a receiving portion for accommodating a part of the pressing member at a position corresponding to a position in which the receiving groove is formed is provided on the outer circumferential surface of the inner clutch, and the inner clutch is of the outer clutch so that the receiving portion and the receiving groove face each other. It can be placed in the accommodation space.

In addition, the receiving portion may be provided to have an inclined surface such that the pressing member compresses the elastic member and slides into the receiving groove when the inner clutch is rotated relative to each other.

In addition, when braking is released or when the actuator fails (power loss), the pressing member moves along the inclined surface of the receiving portion by the elastic restoring force of the elastic member, and the inner clutch returns to its original position by pressing the inner clutch. It can be provided to be released (self release).

In addition, when the elastic member is maximally compressed by the pressing member, the end of the pressing member is provided to protrude from the receiving groove, so that the inclined surface does not escape the pressing member when the inner clutch rotates relative to the outer clutch. It can be provided to limit rotation so that

In addition, the inner clutch and the outer clutch rotate together in a no-load section, and rotation of the outer clutch is prevented by the thrust generated in the spindle when converting from the no-load section to a load section, and only the inner clutch is together with the spindle. It can be arranged to rotate.

In addition, a thrust bearing installed in the accommodation space may be further provided so as to be interposed between the inner clutch and the outer clutch.

The electromechanical brake according to an embodiment of the present invention can improve control precision by implementing an independent mechanism in load and no-load modes.

In addition, when the electromechanical brake loses power, the parking force can be automatically released due to the elastic restoring force, thereby ensuring high stability.

In addition, it prevents separate subsidiary materials such as ball-in lamps or springs from being assembled in the longitudinal direction of the caliper (brake) operation direction, and it is compactly assembled to the spindle within the cylinder to prevent the length of the brake from becoming longer. When installed in a vehicle, it is possible to increase design freedom.

The present invention will be described in detail by the following drawings, but since these drawings show preferred embodiments of the present invention, the technical idea of the present invention is limited only to the drawings and should not be interpreted.
1 is a cross-sectional view showing an electromechanical brake according to an embodiment of the present invention.
2 is an exploded perspective view showing a clutch unit according to an embodiment of the present invention.
3 is a partially cut-away perspective view of the clutch unit of FIG. 2 assembled.
4 is a view showing an operation state in a no-load section when braking an electromechanical brake according to an embodiment of the present invention.
5 is a cross-sectional view showing an operating state of the clutch unit taken along line V-V' of FIG. 4.
6 is a view showing an operation state in a load section when braking an electromechanical brake according to an embodiment of the present invention.
7 is a cross-sectional view showing an operating state of the clutch unit taken along the line VII-VII' of FIG. 6;
8 is a view showing a self-release state by the clutch unit according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented in order to sufficiently convey the spirit of the present invention to those of ordinary skill in the art to which the present invention pertains. The present invention is not limited to the exemplary embodiments presented here, but may be embodied in other forms. In the drawings, in order to clarify the present invention, portions not related to the description may be omitted, and sizes of components may be slightly exaggerated to aid understanding.

1 is a cross-sectional view showing an electromechanical brake according to an embodiment of the present invention, FIG. 2 is an exploded perspective view showing a clutch unit according to an embodiment of the present invention, and FIG. 3 is a partially cutaway perspective view of the clutch unit of FIG. to be.

1 to 3, the electromechanical brake 1 according to the present invention is a carrier 10 in which a pair of pad plates 11 and 12 are installed to press the disk D that rotates together with the wheel of the vehicle. Wow, a caliper housing 20 that is slidably installed on the carrier 10 to operate a pair of pad plates 11 and 12, a piston 21 that is installed in the caliper housing 20 so as to move forward and backward, An actuator (not shown) that provides a rotational force for moving the piston 21, and a rotational force transmitted from the actuator is received and converted into a linear motion and transmitted to the piston 21 so that the piston 21 moves forward and backward in the axial direction. It is installed on the power conversion unit 30 and the spindle 34 of the power conversion unit 30 to rotate with the spindle 34 in the no-load section when driving in a direction to generate the braking force, and to release the braking force in the load section It includes a clutch unit 100 for storing the elastic force.

Friction pads 13 and 14 are attached to the inner surfaces of the pair of pad plates 11 and 12, respectively. A pair of pad plates 11 and 12 are arranged so that their outer surfaces are in contact with the inner pad plates 11 and the outer surfaces are in contact with the fingers 22 of the caliper housing 20 It consists of an outer pad plate 12 that is slidably installed on the carrier 10.

The caliper housing 20 includes a finger 22 for operating the outer pad plate 12 and a cylinder 23 on which the piston 21 is installed, and is slidably fastened to the carrier 10. Accordingly, the caliper housing 20 slides from the carrier 10 and moves to the right by the reaction force caused by the movement of the piston 21 during the braking action, and the outer pad plate by the fingers 22 (12) is pushed toward the disk (D) to press the disk (D).

The piston 21 is provided in a cup shape with one side open, and is slidably inserted into the cylinder 23.

The piston 21 presses the inner pad plate 11 toward the disk D by the axial force of the power conversion unit 30 receiving the rotational force of the actuator.

The power conversion unit 30 serves to press the piston 21 toward the inner pad plate 11 by receiving rotational force from an actuator composed of a motor and a reduction device.

The power conversion unit 30 includes a nut 32 disposed inside the piston 21 and capable of moving forward and backward, and a spindle 34 and a nut 32 that rotates by receiving a rotational force from an actuator to move the nut 32 forward and backward. It includes a plurality of balls (not shown) interposed between the spindle 34. The power conversion unit 30 is a ball screw type linear moving unit that converts rotational motion into linear motion, and a detailed description thereof will be omitted since it is a well-known technique.

On the other hand, although not shown for the actuator, the actuator is composed of a reduction device having a motor and a plurality of reduction gears and is installed outside the caliper housing 20 to be provided to be coupled with the spindle 34 of the power conversion unit 30. I can. Such an actuator is a known technology used in electromechanical brakes, and may be provided to transmit rotational force to the spindle 34 by grafting actuators having various reduction gear structures.

The clutch unit 100 may be installed on the spindle 34 of the power conversion unit 30 to implement an independent mechanism in the no-load section and the load section. At this time, in the no-load section, the nut 32 converts the rotational motion according to the rotation of the spindle 34 into linear motion from the time when the actuator operates and the spindle 34 receives the rotational force, and the inner pad plate through the piston 21 It refers to the operating section of the nut 32 until immediately before contacting the disk D by pressing (11). In addition, the load section refers to a section in which the nut 32 is operated so that the inner pad plate 11 is pressed against the disk D to generate a braking force. That is, the load section is a section in which thrust is generated when the disk D is pressed through the pad plates 11 and 12, and the no-load section is a section in which thrust is not generated.

More specifically, the clutch unit 100 has an outer clutch 110 disposed on the cylinder 23 with the front portion opened, and an inner clutch provided on the spindle 34 to contact the inner circumferential surface of the outer clutch 110 ( 120) and the inner clutch 120 includes a mechanical energy storage unit 130 for storing elastic force when the inner clutch 120 and the outer clutch 110 rotate relative to each other.

The outer clutch 110 is provided in a cylindrical shape in which a front portion is opened so that an inner receiving space 112 is formed, and a hollow 114 is formed so that the spindle 34 passes through the rear portion. As shown, the outer clutch 110 is formed so that its outer surface corresponds to the inner shape of the cylinder 23 and is seated on the rear wall of the cylinder 23. The outer clutch 110 is provided to be rotatable about the spindle 34 in the cylinder 23.

In addition, a receiving groove 113 is formed on the inner circumferential surface of the outer clutch 110 so that a mechanical energy storage unit 130 to be described later is disposed. A plurality of receiving grooves 113 are provided at regular intervals along the inner circumferential surface of the outer clutch 110. As shown, four receiving grooves 113 are formed in the outer clutch 110, but the number is not limited thereto, and the number may be selectively increased or decreased.

The inner clutch 120 is installed on the spindle 34 so as to rotate together with the spindle 34. The inner clutch 120 is made to have a substantially disk shape and is disposed in the receiving space 112 of the outer clutch 110. At this time, the inner clutch 120 is provided to be in close contact with the inner circumferential surface of the outer clutch 110. Accordingly, when the inner clutch 120 rotates together with the spindle 34, the outer clutch 110 rotates together by frictional force.

Meanwhile, a receiving portion 123 may be provided on an outer circumferential surface of the inner clutch 120. A plurality of accommodating portions 123 are provided at regular intervals along the outer peripheral surface of the inner clutch 120. Preferably, the receiving portion 123 is formed to have a number corresponding to the receiving groove 113. Accordingly, the inner clutch 120 may be installed on the outer clutch 110 so that the receiving groove 113 and the receiving portion 123 face each other. The receiving portion 123 supports the pressing member 133 of the mechanical energy storage unit 130 to be described later, and may be formed to accommodate a part of the pressing member 133. In addition, when the inner clutch 120 rotates relative to the outer clutch 110, the pressing member 133 may be formed to have an inclined surface (see '123a' in FIG. 5) so as to move smoothly along the receiving portion 123. have. As shown, the receiving portion 123 is formed to be elongated along the outer peripheral surface of the inner clutch 120, the cross-sectional shape may be provided to have a tapered shape. The state in which the pressing member 133 is operated by the receiving part 123 will be described again below.

The mechanical energy storage unit 130 may be provided between the inner clutch 120 and the outer clutch 110. The mechanical energy storage unit 130 is provided to store an elastic force when the inner clutch 120 rotates relative to the outer clutch 110. More specifically, the mechanical energy storage unit 130 includes an elastic member 131 inserted into the receiving groove 113 formed in the outer clutch 110 and a pressure member 133 elastically supported by the elastic member 131 do.

The elastic member 131 may be provided with a coil spring. Accordingly, one end of the elastic member 131 is supported at the end of the receiving groove 113 and the other end is supported by the pressing member 133. At this time, the elastic member 131 may be stably provided inside the receiving groove 113 and one end may be fixed to the receiving groove 113 so as to be elastically deformed.

The pressing member 133 may be provided in a ball shape. In addition, the pressing member 133 is provided to compress the elastic member 131 and be inserted into the receiving groove 113. The pressing member 133 is supported by being seated on the receiving portion 113 of the inner clutch 120 while the opposite side thereof is supported by the elastic member 131.

Meanwhile, as the clutch unit 100 is installed so that the inner clutch 120 rotates together with the spindle 34, the power conversion unit 30 is operated, thereby displacing the inner pad plate 11 through the piston 21 to the disk (D ), the thrust generated when pressurized is transmitted. Accordingly, the clutch unit 100 further includes a thrust bearing 140 so that the spindle 34 and the inner clutch 120 rotate smoothly by thrust.

The thrust bearing 140 is installed in the receiving space 112 of the outer clutch 110 so as to be interposed between the inner clutch 120 and the outer clutch 110.

Then, a state in which the clutch unit is operated when the electromechanical brake as described above is braked will be described.

First, referring to FIGS. 4 and 5, when the spindle 34, which has received a rotational force from an actuator (not shown), rotates in a clockwise direction, the nut 32 converts the rotational force into linear motion and advances in the axial direction. . Accordingly, the inner pad plate 11 is pressed toward the disk D through the piston 21. At this time, the inner clutch 120 and the outer clutch 110 rotate together in a no-load section in which no load is generated until the friction pad 13 of the inner pad plate 11 contacts the disk D. That is, as the outer circumferential surface of the inner clutch 120 and the inner circumferential surface of the outer clutch 110 are formed in close contact, the inner clutch 120 and the outer clutch 110 due to the frictional force of the inner clutch 120 and the outer clutch 110 Is rotated together with the spindle 34. In addition, the elastic member 131 and the pressing member 133 provided between the inner clutch 120 and the outer clutch 110 also move together.

Next, a state in which the clutch unit 100 is operated in a load section in which the friction pad 13 of the inner pad plate 11 presses the disk D will be described with reference to FIGS. 6 and 7. .

6 and 7, as the friction pad 13 of the inner pad plate 11 comes into contact with the disk D and presses the disk D, thrust in the direction of the arrow T through the power conversion unit 30 Is delivered. That is, the thrust is transmitted to the clutch unit 100 coupled with the spindle 34. Accordingly, rotation of the outer clutch 110 is restricted in a state in close contact with the rear wall of the cylinder 23 by the thrust force. At this time, the inner clutch 120 is provided to be rotatable together with the spindle 34 by the thrust bearing 140. That is, the inner clutch 120 rotates relative to the outer clutch 110. This is because the thrust is greater than the friction between the inner clutch 120 and the outer clutch 110, the rotation of the outer clutch 110 is limited, and the inner clutch 120 is a thrust bearing ( 140) allows rotation.

Accordingly, when the inner clutch 120 rotates in a state where rotation of the outer clutch 110 is restricted, the receiving portion 123 rotates in a direction (clockwise) away from the receiving groove 113. That is, the pressing member 133 slides along the inclined surface 123a of the receiving portion 123 and moves toward the receiving groove 113. Accordingly, the pressing member 133 compresses the elastic member 131 and moves toward the receiving groove 113 to store the elastic force.

On the other hand, when the elastic member 131 is maximally compressed by the pressing member 133, the end portion of the pressing member 133 is provided to protrude from the receiving groove 113. Accordingly, when the inner clutch 120 rotates relative to the outer clutch 110, the inclined surface 123a may be provided to limit the rotation of the inner clutch 120 so that the inclined surface 123a does not deviate from the pressing member 133.

Therefore, the inner clutch 120 and the outer clutch 110 rotate together in the no-load section, and when the no-load section is converted to the load section, the rotation of the outer clutch 110 is prevented by thrust, and only the inner clutch 120 is a spindle ( As it rotates with 34), the mechanical energy storage unit 130 can store the elastic force in the direction of releasing the braking force.

As described above, when braking is released after braking is completed, power is applied to the actuator to generate a rotational force in the opposite direction in which braking force is generated. That is, when the spindle 34 receives the rotational force and rotates counterclockwise, the nut 32 converts the rotational motion into a linear motion and retreats to return to its original position. At this time, as shown in FIG. 8, the inner clutch 120 rotates relative to the outer clutch 110 by the elastic force stored in the mechanical energy storage unit 130 before the nut 32 moves to the no-load section, and the original position Will return to That is, by the elastic restoring force of the elastic member 131, the pressing member 133 presses the inner clutch 120 and moves in the direction of the center of the receiving part 123 along the inclined surface 123a of the receiving part 123. . Therefore, when the inner clutch 120 rotates relative to the outer clutch 110 and returns to its original position, the inner clutch 120 and the outer clutch 110 rotate together with the rotation of the spindle 34.

On the other hand, when the actuator fails after the braking operation, that is, when power is lost, the inner clutch 120 is rotated in the direction in which the brake is released by the elastic force stored in the mechanical energy storage unit 130 to release the parking force. Accordingly, the clutch unit 100 is capable of securing safety performance by performing a self release function.

As described above, although the present invention has been described by a limited embodiment and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the following by those of ordinary skill in the art to which the present invention pertains. It goes without saying that various modifications and variations are possible within the equivalent range of the claims to be described.

1: electromechanical brake 10: carrier
20: caliper housing 21: piston
23: cylinder 30: power conversion unit
32: nut 34: spindle
100: clutch unit 110: outer clutch
113: receiving groove 120: inner clutch
123: receiving part 123a: inclined surface
130: mechanical energy storage unit 131: elastic member
133: pressure member 140: thrust bearing

Claims (9)

A caliper housing provided with a cylinder in which a piston is installed to move forward and backward to press the pad plate;
A power conversion unit including a spindle installed in the cylinder and configured to rotate by receiving a rotational force from an actuator generating a braking force, and a nut coupled to the spindle to convert a rotational motion into a linear motion to move the piston forward and backward; And
An electromechanical brake comprising: a clutch unit installed on the spindle and rotating together with the spindle in a no-load section of the power conversion unit when driving in a direction generating braking force, and storing elastic force in a direction releasing braking force in the load section. . The method of claim 1,
The clutch unit,
A cylindrical outer clutch having a front portion opened so as to form an inner receiving space so as to be rotatably seated on a rear wall of the cylinder, and having a hollow portion formed at the rear portion to allow the spindle to penetrate;
An inner clutch installed on the spindle so as to rotate together with the spindle and disposed in the receiving space so as to contact the inner circumferential surface of the outer clutch; And
An electromechanical brake comprising: a mechanical energy storage unit provided between the outer clutch and the inner clutch to store an elastic force when the inner clutch rotates relative to the outer clutch. The method of claim 2,
The mechanical energy storage unit,
An elastic member inserted into the receiving groove formed at regular intervals along the inner circumferential surface of the outer clutch; And
An electromechanical brake having a; a pressing member elastically supported by the elastic member, compressing the elastic member by pressing, and inserted into the receiving groove. The method of claim 3,
On the outer circumferential surface of the inner clutch, a receiving portion for receiving a part of the pressing member is provided at a position corresponding to the position where the receiving groove is formed,
The inner clutch is an electromechanical brake disposed in the receiving space of the outer clutch so that the receiving portion and the receiving groove face each other. The method of claim 4,
The receiving portion is an electromechanical brake provided to have an inclined surface so that the pressing member compresses the elastic member when the inner clutch rotates relative to each other and slides into the receiving groove. The method of claim 5,
When braking is released or when the actuator fails (power loss), the pressing member moves along the inclined surface of the receiving portion by the elastic restoring force of the elastic member, and by pressing the inner clutch, the inner clutch returns to its original position and self-release ( Electromechanical brake provided to be self release). The method of claim 5,
When the elastic member is maximally compressed by the pressing member, the end of the pressing member is provided to protrude from the receiving groove, and the inclined surface rotates so that the inclined surface does not deviate from the pressing member when the inner clutch rotates relative to the outer clutch. Electromechanical brake provided to limit the. The method of claim 2,
The inner clutch and the outer clutch rotate together in a no-load section, and rotation of the outer clutch is prevented by the thrust generated in the spindle when converting from the no-load section to a load section, and only the inner clutch rotates together with the spindle. Electromechanical brakes provided. The method of claim 2,
An electromechanical brake further comprising a thrust bearing installed in the accommodation space so as to be interposed between the inner clutch and the outer clutch.

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