WO2023074127A1

WO2023074127A1 - Electric brake apparatus and driving unit

Info

Publication number: WO2023074127A1
Application number: PCT/JP2022/033353
Authority: WO
Inventors: 力弥吉津; 広一崎元
Original assignee: 日立Astemo株式会社
Priority date: 2021-10-26
Filing date: 2022-09-06
Publication date: 2023-05-04
Also published as: JPWO2023074127A1

Abstract

Provided is an electric brake apparatus, namely a disc brake, comprising: an electric motor; a spindle driven to rotate by the electric motor; a nut member that moves linearly in the axial direction of a disc rotor as the spindle rotates, and moves inner and outer brake pads; an engaging rotation member that engages with the spindle when the nut member has advanced in the axial direction; and a torsion spring in which elastic energy is stored due to the co-rotation of the spindle and the engaging rotation member while the spindle and the engaging rotation member are engaged. This arrangement allows for reduced bulk.

Description

Electric brake device and drive unit

The present invention relates to an electric brake device and a drive unit.

Patent Document 1 discloses an electric brake including a drive unit that provides power for moving a piston, the drive unit being coupled to a piston installed in a caliper housing and moving axially to move the piston. a nut member that allows the caliper housing to move forward and backward; a spindle that is threadedly engaged with the nut member and axially moves the nut member when rotated; an electric motor that provides power to rotate the spindle; and a friction member that rotates with the spindle due to frictional force when the spindle comes into contact with the friction member; A motorized brake is disclosed that includes an elastic member that stores energy and provides an elastic restoring force on release of the brake as a reverse torque to the spindle using a friction member.

Japanese Patent No. 6746469

However, in the device disclosed in Patent Document 1, elastic energy is stored in the elastic member due to the frictional force generated between the spindle and the friction member. It is necessary to increase the area, which may increase the size of the device.

Therefore, one of the objects of the present invention is to provide an electric brake device and a drive unit that can suppress an increase in size.

As a means for solving the above-described problems, an electric brake device according to the present invention includes an electric motor, a rotating member that rotates when driven by the electric motor, and a linear motion in the axial direction of a disk due to the rotation of the rotating member. a linear motion member that moves the friction pad; a meshing portion that meshes with the rotary member when the linear motion member advances in the axial direction; and an elastic member that stores elastic energy when the rotating member and the meshing portion rotate together.

Further, in the electric brake device according to the present invention, an electric motor, a rotating member connected to the electric motor, a direct-acting member screwed to the rotating member, and arranged to face the rotating member with a predetermined gap therebetween. a meshing portion that meshes with the rotating member when the linear motion member linearly moves; a fixed portion that is provided so as not to rotate relative to the meshing portion; one end of which is connected to the meshing portion; and a torsion spring having a portion connected to the fixed portion.

Further, a drive unit according to the present invention is a drive unit that provides power for pressing a friction pad against a disc of a disc brake, comprising: an electric motor; a rotating member that rotates when driven by the electric motor; a linear motion member that linearly moves when the linear motion member rotates; a meshing portion that meshes with the rotary member when the linear motion member linearly moves; and an elastic member that stores elastic energy when the meshing portion rotates together.

According to one embodiment of the present invention, it is possible to suppress an increase in size.

FIG. 2 is a cross-sectional view of the essential parts of the disc brake according to the present embodiment; FIG. 2 is an exploded perspective view of a fail-open mechanism employed in the disc brake according to this embodiment; FIG. 2 is an exploded perspective view of a fail-open mechanism employed in the disc brake according to this embodiment; 4A and 4B are schematic diagrams showing step by step the operation of the disc brake according to the present embodiment. FIG. The schematic diagram of the disc brake which concerns on other embodiment.

The present embodiment will be described in detail below with reference to FIGS. 1 to 5. FIG.
The disc brake 1A according to this embodiment is an electric brake device that generates a braking force by driving an electric motor 32 during normal running. In the following description, the vehicle inner side (inner side) will be referred to as one end side (cover member 30 side), and the vehicle outer side (outer side) will be referred to as the other end side (disk rotor D side). That is, in FIG. 1, the right side is referred to as one end side, and the left side is referred to as the other end side.

A disc brake 1A according to this embodiment, as shown in FIG. , a caliper 4 and . This disc brake 1A is constructed as a caliper floating type. The pair of inner and

outer brake pads

2 and 3 and the caliper 4 are movably supported in the axial direction of the disk rotor D by a carrier 5 fixed to a non-rotating portion such as a knuckle of the vehicle. Note that the inner brake pad 2 and the outer brake pad 3 correspond to friction pads. Also, the disk rotor D corresponds to the disk.

As shown in FIG. 1, the caliper 4 includes a caliper main body 8, which is the main body of the caliper 4, and a drive unit 9 that provides power for causing the disc rotor D to press the inner brake pad 2 and the outer brake pad 3. ing. The caliper body 8 is arranged on the base end side facing the inner brake pad 2, and has a cylindrical cylinder portion 13 that opens facing the inner brake pad 2, and an outer side extending from the cylinder portion 13 across the disk rotor D. A pair of claw portions 14 , 14 (one of which is not shown) are arranged on the distal end side (the other end side), extending to the outer brake pad 3 .

A piston 18 is accommodated in the cylinder portion 13 of the caliper body 8, that is, in the cylinder bore 16 of the cylinder portion 13 so as to be non-rotatable relative to the cylinder portion 13 and to be axially movable. The piston 18 presses the inner brake pad 2 and is shaped like a cup with a bottom. The piston 18 is housed in the cylinder bore 16 so that its bottom faces the inner brake pad 2 . The piston 18 is supported so as not to rotate relative to the cylinder bore 16 and thus to the caliper body 8 by the anti-rotation engagement between the bottom portion of the piston 18 and the inner brake pad 2 .

A seal member 20 is arranged on the inner peripheral surface of the other end of the cylinder bore 16 of the cylinder portion 13 . The piston 18 is accommodated in the cylinder bore 16 so as to be axially movable while contacting the seal member 20 . A dust boot 21 is interposed between the outer wall portion on the bottom side of the piston 18 and the inner peripheral surface on the other end side of the cylinder bore 16 . The sealing member 20 and the dust boot 21 prevent foreign matter from entering the cylinder bore 16 of the cylinder portion 13 .

A gear housing 28 is integrally connected to the bottom wall 23 side (one end side) of the cylinder portion 13 . An insertion hole 25 is provided in the bottom wall 23 of the cylinder portion 13 , and a spindle 40 , which will be described later, extends into the gear housing 28 through the insertion hole 25 . One end side opening of the gear housing 28 is airtightly closed by a cover member 30 . A drive unit 9 is arranged in the gear housing 28 and in the cylinder bore 16 of the cylinder part 13 . The drive unit 9 transmits rotation from the electric motor 32 to the piston 18 in the cylinder bore 16 of the cylinder portion 13, and presses the inner brake pad 2 and the outer brake pad 3 against the disk rotor D by the thrust of the piston 18. It is for

The drive unit 9 includes an electric motor 32, a gear reduction mechanism 33 to which rotation from the electric motor 32 is transmitted, and a gear reduction mechanism 33 that increases the rotational torque from the electric motor 32, and a rotation from the gear reduction mechanism 33 that converts the rotation into linear motion. a rotation-to-linear motion conversion mechanism 34 that applies thrust to the piston 18; a fail-open mechanism 35 that releases the braking force when the electric motor 32 cannot be driven normally due to a failure of the power supply or the like during braking; It has The electric motor 32 and gear reduction mechanism 33 are accommodated within the gear housing 28 . The gear reduction mechanism 33 increases the rotational torque from the electric motor 32 and transmits it to the rotation/linear motion conversion mechanism 34 . A planetary gear reduction mechanism or the like is adopted as the gear reduction mechanism 33 . The rotation-to-linear motion conversion mechanism 34 and the fail-open mechanism 35 are accommodated in the cylinder bore 16 of the cylinder portion 13 .

The rotation-to-linear motion conversion mechanism 34 includes a spindle 40 to which rotation from the gear reduction mechanism 33 is transmitted, and a nut member 41 screwed onto the spindle 40 . In this embodiment, the spindle 40 corresponds to the rotary member, and the nut member 41 corresponds to the linear motion member. As shown in FIGS. 1 to 3, the spindle 40 includes a spline shaft portion 43 provided on one end side, a male thread portion 44 provided on the other end side, and radially extending from a position on the one end side of the male thread portion 44. and an annular support portion 45 protruding toward it. A spline shaft portion 43 of the spindle 40 is connected to an output member (not shown) of the gear reduction mechanism 33 in the gear housing 28 so as not to rotate relative thereto. As a result, rotational torque can be transmitted between the output member of the gear reduction mechanism 33 and the spindle 40 . The spindle 40 is axially movable by a reaction force from the disc rotor D due to the sandwiching between the pair of inner and

outer brake pads

2 and 3 .

With reference to FIG. 1, one end face of the annular support portion 45 is configured such that its outer diameter gradually decreases toward the one end side in a stepwise manner. In short, referring also to FIG. 2, the one end face of the annular support portion 45 consists of a large diameter one end face 46A located on the outermost periphery on the other end side and an intermediate diameter end face located on the one end side of the large diameter one end face 46A. 46B, and a small diameter one end face 46C located on the one end side of the intermediate diameter one end face 46B. An engaging uneven portion 48 is continuously formed along the circumferential direction over the entire large-diameter end surface 46A of the annular support portion 45 . The engagement uneven portion 48 is one component of the fail-open mechanism 35, which will be described later.

As shown in FIG. 1 , a thrust bearing 50 is arranged between the annular support portion 45 of the spindle 40 and the bottom wall 23 of the cylinder portion 13 . The thrust bearing 50 rotatably supports the spindle 40 on the bottom wall 23 of the cylinder portion 13 . The thrust bearing 50 includes a first annular thrust plate 51 arranged on the bottom wall 23 side of the cylinder portion 13, a second annular thrust plate 52 arranged on the annular support portion 45 side of the spindle 40, and a first thrust plate 52 arranged on the annular support portion 45 side of the spindle 40. and a plurality of thrust balls 53 that are rotatably arranged between the plate 51 and the second thrust plate 52 .

A rolling groove 51A in which each thrust ball 53 rolls is formed on the other end surface of the first thrust plate 51 . One end face of the second thrust plate 52 is formed with a rolling groove 52A in which each thrust ball 53 rolls. A plurality of thrust balls 53 are rotatably arranged between the rolling grooves 51A of the first thrust plate 51 and the rolling grooves 52A of the second thrust plate 52 . The plurality of thrust balls 53 are held by retainers 55 at regular intervals in the circumferential direction. The spindle 40 is inserted through the first and

second thrust plates

51 and 52 of the thrust bearing 50 .

As shown in FIGS. 1 to 3, the nut member 41 is arranged radially outward of the male threaded portion 44 of the spindle 40 . The nut member 41 is formed in a cylindrical shape. A female threaded portion 57 is formed on the inner peripheral surface of the nut member 41 on the one end side. The male threaded portion 44 of the spindle 40 and the female threaded portion 57 of the nut member 41 are screwed together. The nut member 41 is supported so as not to rotate relative to the piston 18 . This allows the nut member 41 to move along the axial direction as the spindle 40 rotates. As can be seen from FIGS. 1 and 2, a plurality of longitudinal engaging grooves 59 extending in the axial direction are formed in the outer peripheral surface of the nut member 41 along the circumferential direction. In this embodiment, two longitudinal engagement grooves 59 are formed at a pitch of 180°.

As shown in FIG. 1, a fail-open mechanism 35 is provided on the radially outer side of the nut member 41 to quickly release the braking force in the event of a failure of the power supply or the like. 2 and 3, the fail-open mechanism 35 includes a fixed member 64, a torsion spring 65, an engaging rotating member 66, and a wave washer 67. As shown in FIG. As shown in FIGS. 1-3, the fixing member 64 is generally cylindrical. The fixing member 64 is arranged radially outward from the outer peripheral surface of the nut member 41 with an annular gap 77 interposed therebetween. The fixing member 64 is composed of a large-diameter fixing portion 69 arranged on one end side, and a small-diameter fixing portion 70 provided continuously from the large-diameter fixing portion 69 on the other end side.

On the outer peripheral surface of one end of the large-diameter fixing portion 69, a plurality of regulation groove portions 72 are formed in a predetermined range along the circumferential direction at intervals along the circumferential direction. In this embodiment, the regulation grooves 72 are formed at two locations with 180 pitches. Each projection piece 80 provided on the engaging rotating member 66 , which will be described later, is engaged with each regulation groove portion 72 . Each restricting groove 72 is recessed from its circumferential end toward one end surface of the large-diameter fixing portion 69 so as to match the bottom surface of the restricting groove 72 . Referring to FIG. 3, the small-diameter fixing portion 70 is provided with a bulging portion 73 in which a part along the circumferential direction of the peripheral wall portion bulges radially outward. The bulging portion 73 extends axially, and an axially extending accommodation groove 74 is formed therein.

As shown in FIGS. 1 to 3, a plurality of engaging protrusions 76 projecting inward are provided at intervals in the circumferential direction on the inner peripheral surface of the small-diameter fixing portion 70 of the fixing member 64 . The engaging protrusion 76 extends axially. In the present embodiment, two engaging protrusions 76 are formed at a pitch of 180°. Then, referring to FIG. 1 , each engaging protrusion 76 provided on the small-diameter fixing portion 70 of the fixing member 64 is engaged with each engaging vertical groove 59 provided on the outer peripheral surface of the nut member 41 . As a result, the fixed member 64 is connected to the nut member 41 so as to be non-rotatable relative to the nut member 41 and movable relative to the nut member 41 along the axial direction. Note that, in the present embodiment, the fixing member 64 corresponds to the fixing portion. As shown in FIG. 1, an engaging rotating member 66 is arranged from the radially outer side of one end side of the fixing member 64 toward the one end side.

As shown in FIGS. 1 to 3, the engaging rotating member 66 is formed in a cylindrical shape as a whole, and includes a cylindrical portion 78 and an annular flange portion 79 extending radially inward from one end of the cylindrical portion 78. , is equipped with A plurality of projecting pieces 80 protruding inward are formed at intervals in the circumferential direction on the peripheral wall portion on the other end side of the cylindrical portion 78 . In this embodiment, the protrusion pieces 80 are formed at two locations at a pitch of 180°. Each projecting piece 80 is formed by bending the entire peripheral wall portion of the cylindrical portion 78 inward. Then, referring to FIG. 1 , each projecting piece 80 of the cylindrical portion 78 of the engaging rotating member 66 is engaged with each restricting groove portion 72 provided on the outer peripheral surface of the large-diameter fixing portion 69 of the fixing member 64 . As a result, the engaging rotating member 66 is rotatably supported relative to the fixed member 64 within the range of each regulation groove portion 72 . In addition, the fixed member 64 is relative to the meshing rotary member 66 along the axial direction by the difference between the width length (length in the axial direction) of the regulation groove portion 72 of the fixed member 64 and the thickness of the projecting piece 80 . becomes movable.

In other words, an angle regulating means 82 is provided between the engaging rotating member 66 and the fixed member 64 to regulate the mutual relative rotation angle. In this embodiment, the angle regulating means 82 includes each regulating groove portion 72 provided in the large-diameter fixing portion 69 of the fixing member 64 and the cylindrical portion of the engaging rotating member 66 that is engaged with each of the regulating groove portions 72 . Each projection piece 80 provided on 78 is provided. As shown in FIGS. 2 and 3, a slit 83 extending axially from the other end of the cylindrical portion 78 of the engaging rotating member 66 is formed in the peripheral wall portion. A plurality of engaging

projections

84 , 84 are radially formed on the other end surface of the annular flange portion 79 . In this embodiment, the engaging

projections

84, 84 are formed at two locations at a pitch of 180°. Three or more

engaging protrusions

84, 84 may be provided at equal intervals in the circumferential direction. In addition, in this embodiment, the mesh|engagement rotation member 66 corresponds to a meshing part.

As shown in FIG. 1 , the torsion spring 65 is arranged in an annular gap 77 provided between the inner peripheral surface of the large-diameter fixing portion 69 of the fixing member 64 and the outer peripheral surface of the nut member 41 . The torsion spring 65 corresponds to an elastic member. As shown in FIG. 2 , one end of the torsion spring 65 protrudes radially outward and is inserted through a slit 83 provided in the engaging rotating member 66 . On the other hand, as shown in FIG. 3 , the other end of the torsion spring 65 extends in the axial direction, and the other end is inserted through a housing groove 74 provided in the small-diameter fixing portion 70 of the fixing member 64 . In the initial state before the electric motor 32 rotates in the braking direction, each projecting piece 80 of the engaging rotating member 66 is positioned at either end of each regulation groove 72 of the fixing member 64 (large-diameter fixing portion 69). , both ends of the torsion spring 65 are inserted into the slit 83 of the engaging rotating member 66 and the housing groove 74 of the fixing member 64, respectively, and a predetermined set load is applied to the torsion spring 65. .

As shown in FIG. 1 , the annular flange portion 79 of the engaging rotating member 66 is arranged between the second thrust plate 52 of the thrust bearing 50 and the large diameter one end surface 46A of the annular support portion 45 of the spindle 40 . That is, referring to FIGS. 2 and 3 as well, the engagement uneven portion 48 provided on the large-diameter one end face 46A of the annular support portion 45 of the spindle 40 and the engagement provided on the annular flange portion 79 of the engaging rotating member 66. The

protrusions

84, 84 are arranged so as to face each other. As shown in FIGS. 1 and 2, radially inward from the annular flange portion 79 of the meshing rotating member 66, the second thrust plate 52 of the thrust bearing 50 and the intermediate diameter one end surface of the annular support portion 45 of the spindle 40 A wave washer 67 is arranged between 46B and the small diameter one end face 46C.

The wave washer 67 urges the spindle 40 away from the thrust bearing 50 along the axial direction (toward the other end). Note that the wave washer 67 corresponds to an elastic body. That is, in a state in which rotation in the braking direction is not applied by the electric motor 32, more specifically, in a state in which no reaction force is applied from the disk rotor D due to the pinching of the pair of inner and

outer brake pads

2 and 3, the wave Since the washer 67 urges the spindle 40 in the direction away from the thrust bearing 50 along the axial direction, it meshes with the engagement uneven portion 48 provided on the large-diameter one end surface 46A of the annular support portion 45 of the spindle 40. A gap along the axial direction is generated between the engaging

projections

84, 84 provided on the annular flange portion 79 of the rotating member 66 (see FIGS. 4A, 4B, and 4D).

The driving of the electric motor 32 shown in FIG. 1 is controlled by a command from a control device (not shown). During braking during normal driving, the control board receives, for example, a detection sensor (not shown) that responds to the driver's request, a detection signal from a detection sensor (not shown) that detects various situations that require braking, and a wheel A detection signal from a wheel speed detection sensor (not shown) that detects the speed, a detection signal from a rotation angle detection means (not shown) that detects the rotation angle of the electric motor 32, and a disc from the inner and

outer brake pads

2 and 3 It controls the rotation (rotation direction, rotation speed, etc.) of the electric motor 32 based on various detection signals such as a detection signal from a thrust sensor (not shown) that detects the thrust (pressing force) to the rotor D. is.

Next, in the disc brake 1A according to the present embodiment, the operation of braking and braking during normal running will be described based on FIG. 4 and also with reference to FIGS. 1 to 3. FIG.
During braking in normal running, the electric motor 32 (see FIG. 1) is driven by a command from the control device from the state of FIG. is transmitted to the spindle 40 via the Subsequently, when the spindle 40 rotates with the rotation of the gear reduction mechanism 33, the nut member 41 screwed with the spindle 40 advances and the piston 18 advances, as shown in FIG. 4(b). The inner brake pad 2 is pressed against the disc rotor D by advancing the piston 18 . Then, the caliper body 8 moves toward the inner side with respect to the carrier 5 due to the reaction force against the pressing force of the piston 18 against the inner brake pad 2, and the claw portions 14, 14 (one is not shown) act as outer brakes. The pad 3 is pressed against the disk rotor D. In the above description, two

claw portions

14, 14 are provided, but the number of claw portions 14 provided on the caliper body 8 may be one. As a result, as shown in FIG. 4(c), the disc rotor D is sandwiched between the pair of inner and

outer brake pads

2, 3 to generate a frictional force, which in turn generates a braking force for the vehicle. .

During this braking, the disk rotor D is sandwiched between the pair of inner and

outer brake pads

2 and 3, and when the disk rotor D begins to be pressed, the reaction force is transmitted to the piston 18, nut member 41 and spindle 40. Then, as shown in FIG. 4(c), the spindle 40 retreats against the urging force of the wave washer 67. Then, as shown in FIG. Then, the engagement uneven portion 48 provided on the annular support portion 45 of the spindle 40 and the engagement

convex portions

84, 84 provided on the annular flange portion 79 of the engaging rotating member 66 are engaged. From the time of this meshing, as the spindle 40 rotates in the braking direction, the meshing rotating member 66 rotates in the same direction. When the rotating engaging member 66 rotates relative to the fixed member 64 in the braking direction, the torsion spring 65 disposed between the rotating engaging member 66 and the fixed member 64 is elastically deformed in the torsional direction. Stores elastic energy. In the disc brake 1A according to this embodiment, the braking force is determined by the spring constants of the wave washer 67 and the caliper main body 8.

On the other hand, when the brake is released, the electric motor 32 rotates in the reverse direction, that is, in the brake release direction, and the reverse rotation is transmitted to the spindle 40 via the gear reduction mechanism 33 according to a command from the control device. As a result, as the spindle 40 rotates in the opposite direction, the nut member 41 screwed with the spindle 40 retreats and returns to the initial state, and the pair of inner and

outer brake pads

2, 3 to the disc rotor D is restored. is released.

That is, when the brake is released, in the initial stage when the spindle 40 rotates in the brake release direction, as shown in FIG. When the spindle 40 rotates in the braking release direction, the engaging rotating member 66 also rotates in the same direction. The elastically deformed torsion spring 65 is also restored. The restoring force of the torsion spring 65 is assisted by the spindle 40 rotating in the brake releasing direction as rotational torque in the brake releasing direction, and the braking force is quickly reduced. Subsequently, as shown in FIG. 4(d), the reaction force from the disc rotor D to the spindle 40 due to the pinching of the pair of inner and

outer brake pads

2, 3 is reduced, and the urging force of the wave washer 67 is reduced. As a result, the spindle 40 moves to the other end side, and the engagement uneven portion 48 provided on the annular support portion 45 of the spindle 40 and the

engagement protrusions

84, 84 provided on the annular flange portion 79 of the engaging rotating member 66 are spaced apart along the axial direction to release their meshing state.

After that, by continuing to rotate the electric motor 32 in the braking release direction, the nut member 41 and the piston 18 are retracted to the initial position, and the inner brake pad 2, the outer brake pad 3, and the disc rotor D are separated. A predetermined clearance is provided between them, and the braking force is completely released. At this time, the engagement uneven portion 48 of the spindle 40 (annular support portion 45) and the

engagement projections

84, 84 of the engaging rotary member 66 (annular flange portion 79) are separated along the axial direction. Therefore, the engagement rotating member 66 does not rotate with the rotation of the spindle 40 in the braking release direction.

In addition, when the power source or the like fails during braking and the electric motor 32 does not generate rotational torque, the fail-open mechanism 35 operates. That is, if the electric motor 32 is not normally driven during braking, the torsion spring 65 elastically deformed during braking is restored, that is, the elastic energy stored during braking is released. Then, as shown in FIG. 4(c), during braking, the engagement uneven portion 48 provided on the annular support portion 45 of the spindle 40 and the engagement protrusions provided on the annular flange portion 79 of the engaging rotating member 66 84 , 84 are engaged with each other, and the restoring force of the torsion spring 65 rotates the spindle 40 together with the engaging rotating member 66 relative to the fixed member 64 in the braking release direction. As a result, the nut member 41 and the piston 18 retreat, and the braking force exerted on the disc rotor D by the pair of inner and

outer brake pads

2, 3 is reduced. In other words, when the electric motor 32 cannot be driven normally, the fail-open mechanism 35 operates to rotate the engaging rotating member 66 by the restoring force of the torsion spring 65 which is elastically deformed during braking, and rotates the spindle 40 in the braking release direction. to decrease the braking force.

Further, the restoring force of the torsion spring 65 advances the rotation of the spindle 40 in the braking release direction, and when the reduction in braking force advances, the disc rotor D detaches from the spindle 40 due to the pinching of the pair of inner and

outer brake pads

2 and 3 . As shown in FIG. 4(d), the biasing force of the wave washer 67 causes the engaging concave-convex portion 48 of the spindle 40 (annular support portion 45) and the engaging rotating member 66 ( The engagement state of the annular flange portion 79) with the respective engaging

protrusions

84, 84 is released. As a result, since the restoring force of the torsion spring 65 is no longer transmitted to the spindle 40, the braking force of the pair of inner and

outer brake pads

2, 3 to the disc rotor D is maintained in a state where it is applied to some extent, and the vehicle is kept safe. You can move it to any place and stop it.

As described above, the disc brake 1A according to the present embodiment particularly includes the spindle 40 that rotates when driven by the electric motor 32, and the rotation of the spindle 40 that moves along the axial direction of the disc rotor D. A nut member 41 for moving the inner and

outer brake pads

2, 3 and the nut member 41 advance in the axial direction and mesh with the spindle 40 retreated by the reaction force from the disk rotor D of the inner and

outer brake pads

2, 3. A meshing rotating member 66 and a torsion spring 65 in which elastic energy is stored by rotating the spindle 40 and the meshing rotating member 66 together in a state where the spindle 40 and the meshing rotating member 66 are meshed.

As a result, compared to the prior art (electric brake described in Patent Document 1) in which a friction member is provided that rotates together with the spindle due to the frictional force of contact with the spindle, the meshing rotating member 66 and the A contact area with the spindle 40 can be reduced, and an increase in size along the radial direction of the cylinder portion 13 (cylinder bore 16) can be suppressed.

Further, in the disc brake 1A according to the present embodiment, the engagement between the spindle 40 and the engagement rotary member 66 causes the engagement rotary member 66 to rotate relative to the fixed member 64 as the spindle 40 rotates. Since the elastic energy is accumulated in the rotatable member 66, it is less susceptible to changes in the surrounding environment due to temperature, contamination, etc., and changes over time in the friction portion between the spindle and the friction member. Variation can be reduced.

Furthermore, in the disc brake 1A according to the present embodiment, the engaging uneven portion 48 provided on the annular support portion 45 of the spindle 40 and the engaging

convex portions

84, 84 provided on the annular flange portion 79 of the engaging rotating member 66 are engaged with each other, the rotation is transmitted between the spindle 40 and the engaging rotating member 66 . As a result, since the thrust along the axial direction is not applied to the engaging uneven portion 48 of the spindle 40 and the engaging

convex portions

84, 84 of the engaging rotating member 66, the input torque is small. 48 and the engaging projections 84 of the engaging rotating member 66 can be made smaller and made of resin (cost reduction). That is, the fixed member 64 and the engaging rotating member 66 of the fail-open mechanism 35 can be made of synthetic resin or the like.

Furthermore, in the disc brake 1A according to the present embodiment, by providing the angle regulating means 82 between the fixed member 64 and the engaging rotating member 66, in the initial state before the electric motor 32 rotates in the braking direction, torsion The spring 65 can be installed with a predetermined set load applied. As a result, it is possible to improve the responsiveness (rapid elastic deformation) of the torsion spring 65 to the rotation of the engaging rotating member 66 during braking. In short, the torsion spring 65 is elastically deformed even by a slight rotation of the engaging rotating member 66 so that elastic energy can be stored, and the responsiveness to the torsion spring 65 can be improved.

Furthermore, in the disc brake 1A according to the present embodiment, the wave force is applied in the direction of separating the engagement projections 48 of the spindle 40 from the

respective engagement projections

84, 84 of the engaging rotating member 66 along the axial direction. A washer 67 is provided. As a result, for example, when it is no longer necessary to rotate the spindle 40 and the engaging rotating member 66 together, the wave washer 67 allows the engagement uneven portion 48 of the spindle 40 and the engaging protrusions 84 of the engaging rotating member 66 to rotate. The meshing state with 84 can be quickly released, and the spindle 40 can be rotated relative to the meshing rotating member 66 .

As a result, when the electric motor 32 cannot be driven normally due to a failure of the power supply or the like, it is possible to maintain the braking force applied to the disk rotor D by the pair of inner and

outer brake pads

2 and 3 to some extent. It is possible to achieve the intended effect. In short, the elastic force (biasing force) of the wave washer 67 against the reaction force (pressing force) of the pair of inner and

outer brake pads

2, 3 to the disk rotor D is appropriately set. Timing for engaging the engaging projections 48 of the spindle 40 and the respective engaging projections 84 of the engaging rotating member 66 with respect to the pressing force (reaction force) of the

outer brake pads

2, 3, or the engagement thereof By appropriately setting the timing for canceling the state, various other intended effects can be achieved.

Furthermore, in the disc brake 1A according to the present embodiment, the engagement of the engagement rugged portion 48 of the spindle 40 and the

respective engagement projections

84, 84 of the engagement rotary member 66 causes the spindle 40 and the engagement rotary member to engage with each other. 66 are meshed with each other, there is no need to increase the contact area between the spindle and the friction member in order to increase the transmission torque, unlike the conventional technology (the electric brake described in Patent Document 1). , the size can be reduced along the radial direction of the cylinder portion 13 (cylinder bore 15).

In this embodiment, the engagement uneven portion 48 is continuously provided along the circumferential direction of the entire large-diameter one end face 46A of the annular support portion 45 of the spindle 40, and other than the annular flange portion 79 of the engaging rotating member 66, A plurality of engaging protrusions 84, 84 (in this embodiment, two engaging protrusions) are provided radially on the end surface, and a plurality of radially extending portions are provided on the large-diameter one end surface 46A of the annular support portion 45 of the spindle 40. The engaging

protrusions

84, 84 may be provided, and the engaging uneven portion 48 may be continuously provided along the circumferential direction over the entire other end surface of the annular flange portion 79 of the engaging rotating member 66.

In short, when the large-diameter end surface 46A of the annular support portion 45 of the spindle 40 and the other end surface of the annular flange portion 79 of the engaging rotating member 66 come into contact with each other, the spindle 40 and the engaging rotating member 66 rotate together. It is sufficient to provide an engaging means such as a concave-convex engagement that prevents relative rotation. The non-relatively rotatable engaging means engages the large-diameter one end surface 46A of the annular support portion 45 of the spindle 40 and the other end surface of the annular flange portion 79 of the engaging rotating member 66 so as to be non-rotatable relative to each other when they come into contact with each other. It may be configured to engage, engage, engage or hook.

Furthermore, in the disc brake 1A according to the present embodiment, two engaging

projections

84, 84 are provided at a pitch of 180° on the other end surface of the annular flange portion 79 of the engaging rotating member 66. As shown in FIG. In this way, by arranging at least two

projections

84, 84 so as to face each other in the radial direction, when the spindle 40 and the engaging rotating member 66 rotate together, both rotate torque in the rotating direction in a well-balanced manner. can be transmitted. In other words, when the spindle 40 (engaging rotating member 66) rotates, the rotation from the spindle 40 (engaging rotating member 66) can be smoothly transmitted to the engaging rotating member 66 (spindle 40) in a well-balanced manner.

Next, a disc brake 1B according to another embodiment will be described with reference to FIG. When describing the disc brake 1B according to the other embodiment, only differences from the disc brake 1A according to the present embodiment shown in FIGS. 1 to 4 will be described.
In a disc brake 1B according to another embodiment, a nut member 100 as a rotation/linear motion conversion mechanism 34 is connected to an output member of a gear speed reduction mechanism 33 so as not to rotate relative to it. As a result, rotational torque is transmitted between the output member of the gear reduction mechanism 33 and the nut member 100 . A push rod 101 is screwed into the nut member 100 . The push rod 101 is supported in the cylinder portion 13 so as to be relatively non-rotatable and movable along the axial direction. As the nut member 100 rotates, the push rod 101 moves along the axial direction. In other embodiments, the nut member 100 corresponds to the rotating member, and the push rod 101 corresponds to the linear motion member.

An annular flange portion 105 projects radially outward from the other end of the nut member 100 . On one end surface of the annular flange portion 105, on the outer circumference thereof, an engaging uneven portion 48 is continuously provided in the entire circumferential direction. A wave washer 67 is arranged between a portion of the annular flange portion 105 inside the engagement uneven portion 48 and the thrust bearing 50 . The wave washer 67 urges the nut member 100 away from the thrust bearing 50 along the axial direction (toward the other end). An engaging rotary member 66 is arranged on one end side of the annular flange portion 105 of the nut member 100 . The engaging rotating member 66 is formed in a cylindrical shape as a whole. The engaging rotating member 66 includes a cylindrical portion 107 and an annular flange portion 108 extending radially inward from the other end of the cylindrical portion 107 . A slit (not shown) extending axially from one end face of the cylindrical portion 107 is formed in the peripheral wall portion of the cylindrical portion 107 . A plurality of engaging

projections

84 , 84 are radially formed on the other end surface of the annular flange portion 108 . Two

engaging projections

84, 84 are formed at a pitch of 180°.

When the electric motor 32 is not rotating in the braking direction, the wave washer 67 urges the nut member 100 away from the thrust bearing 50 along the axial direction (toward the other end). Therefore, there is a gap along the axial direction between the engaging uneven portion 48 provided on the annular flange portion 105 of the nut member 100 and the respective engaging

convex portions

84, 84 provided on the annular flange portion 108 of the engaging rotating member 66. occurs.

A fixed member 64 is arranged on one end side of the meshing rotating member 66 . Between the engaging rotating member 66 and the fixed member 64, there is provided an angle regulating means (not shown) for regulating the mutual relative rotation angle. The fixing member 64 is formed in a cylindrical shape as a whole. The fixing member 64 is formed with an annular fixing portion 110 extending inwardly from one end thereof. A slit (not shown) extending radially from the inner wall surface of the annular fixing portion 110 is formed. The fixed member 64 is supported so as not to rotate relative to the cylinder portion 13 . Note that, in other embodiments, the fixing member 64 corresponds to the fixing portion.

The other end of the torsion spring 65 protrudes radially outward and is inserted through a slit provided in the engaging rotating member 66 . On the other hand, one end of the torsion spring 65 extends in the axial direction and is inserted through a slit provided in the annular fixing portion 110 of the fixing member 64 .

In the disc brake 1B according to another embodiment, during braking during normal running, the electric motor 32 is driven by a command from the control device, and the rotation in the braking direction is transmitted through the gear reduction mechanism 33 to the nut member 100. is transmitted to Subsequently, when the nut member 100 rotates with the rotation of the gear reduction mechanism 33, the push rod 101 threadedly engaged with the nut member 100 moves forward to move the piston 18 forward. As the piston 18 advances, the inner brake pad 2 and the outer brake pad sandwich the disc rotor D to generate a braking force.

During this braking, the disc rotor D is sandwiched between the pair of inner and

outer brake pads

2 and 3, and when the disc rotor D begins to be pushed, the reaction force is transmitted to the piston 18, push rod 101 and nut member 100. As a result, the nut member 100 retreats against the biasing force of the wave washer 67 . Then, the engaging uneven portion 48 provided on the annular flange portion 105 of the nut member 100 and the engaging

convex portions

84, 84 provided on the annular flange portion 108 of the engaging rotating member 66 are engaged. From the time of engagement, the engaging rotating member 66 rotates in the same direction as the nut member 100 rotates in the braking direction. When the rotating engaging member 66 rotates relative to the fixed member 64 in the braking direction, the torsion spring 65 disposed between the rotating engaging member 66 and the fixed member 64 is elastically deformed in the torsional direction. Stores elastic energy.

On the other hand, if the power supply or the like fails during braking and no rotational torque is generated from the electric motor 32, the fail-open mechanism 35 operates. That is, if the electric motor 32 is not driven normally during braking, the torsion spring 65 elastically deformed during braking restores and the elastic energy stored during braking is released. Then, during braking, the engaging concave-convex portion 48 provided on the annular flange portion 105 of the nut member 100 and the engaging

convex portions

84, 84 provided on the annular flange portion 110 of the engaging rotating member 66 are engaged with each other. , the restoring force of the torsion spring 65 rotates the nut member 100 together with the engaging rotating member 66 relative to the fixed member 64 in the braking release direction. As a result, the push rod 101 and the piston 18 are retracted, and the braking force exerted on the disk rotor D by the pair of inner and

outer brake pads

2, 3 is reduced. That is, when the electric motor 32 cannot be driven normally, the restoring force of the torsion spring 65 rotates the engaging rotating member 66 relative to the fixed member 64 and rotates the nut member 100 in the direction of releasing the braking. reduce power.

By reducing the reaction force from the disk rotor D to the nut member 100 due to the pinching of the pair of inner and

outer brake pads

2 and 3, the urging force of the wave washer 67 causes the nut member 100 (annular flange portion 105 ) and the engaging

protrusions

84, 84 of the engaging rotary member 66 (annular flange portion 110) are released. As a result, the restoring force of the torsion spring 65 is no longer transmitted to the nut member 100, so that the braking force of the pair of inner and

outer brake pads

2, 3 to the disk rotor D is maintained in a state where it is applied to some extent, and the vehicle is maintained. It can be moved to a safe place and parked.

With the disc brake 1B according to another embodiment described above, the same effects as the disc brake 1A according to the embodiment shown in FIGS. 1 to 4 can be obtained. Also, the disk brake 1B according to another embodiment can be made smaller in the axial direction than the disk brake 1A according to the embodiment shown in FIGS.

It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration.

This application claims priority based on Japanese Patent Application No. 2021-174651 filed on October 26, 2021. The entire disclosure, including the specification, claims, drawings, and abstract of Japanese Patent Application No. 2021-174651 filed on October 26, 2021, is incorporated herein by reference in its entirety.

1A, 1B disk brake (electric brake device), inner brake pad (friction pad), 3 outer brake pad (friction pad), 9 drive unit, 32 electric motor, 34 rotation/linear motion conversion mechanism, 35 fail-open mechanism, 40 spindle (rotating member), 41 nut member (linear motion member), 48 engaging uneven portion, 62 fail-open mechanism, 64 fixed member (fixed portion), 65 torsion spring (elastic member), 66 meshing rotating member (meshing portion), 67 Wave washer (elastic body), 84 Engagement projection (projection), 100 Nut member (rotating member), 101 Push rod (linear motion member), D Disk rotor (disk)

Claims

An electric braking device, the electric braking device comprising:
an electric motor;
a rotating member that rotates when driven by the electric motor;
a linear motion member that linearly moves in the axial direction of the disc by rotation of the rotary member to move the friction pad;
a meshing portion that meshes with the rotary member when the linear motion member advances in the axial direction;
an elastic member that stores elastic energy when the rotating member and the meshing portion rotate together in a state where the rotating member and the meshing portion are meshed with each other.
The electric brake device according to claim 1,
The elastic member is
accumulating the elastic energy at the time of forward movement in which the friction pad is moved in the direction of pressing against the disk by forward rotation of the electric motor;
An electric brake device that applies reverse torque to the rotating member by releasing the elastic energy during reverse movement of the friction pad in a direction away from the disc by reverse rotation of the electric motor.
The electric brake device according to claim 2,
The electric brake device, wherein the elastic member is a torsion spring.
The electric brake device according to claim 1,
The electric brake device, wherein the elastic member is installed with a set load applied.
The electric brake device according to claim 1,
An electric brake device, comprising an elastic body that biases the rotating member in a direction to separate it from the meshing portion.
The electric brake device according to claim 1,
An electric brake device in which the rotating member and the meshing portion mesh with each other as the rotating member and the meshing portion are engaged with each other.
The electric brake device according to claim 6,
An electric brake device, wherein two projections are provided at a pitch of 180° on the rotating member or the meshing portion.
The electric brake device according to claim 1,
the rotating member is a spindle;
The electric brake device, wherein the direct-acting member is a nut member that screws together with the spindle.
The electric brake device according to claim 1,
The rotating member is a nut member,
The electric brake device, wherein the direct-acting member is a push rod that screws together with the nut.
an electric motor;
a rotating member connected to the electric motor;
a linear motion member threadedly engaged with the rotating member;
a meshing portion disposed facing the rotating member with a predetermined gap, and meshing with the rotating member when the linear motion member linearly moves;
a fixing portion provided so as not to rotate relative to the meshing portion;
and a torsion spring having one end connected to the meshing portion and the other end connected to the fixing portion.
A drive unit for powering a disc of a disc brake against a friction pad, the drive unit comprising:
an electric motor;
a rotating member that rotates when driven by the electric motor;
a linear motion member that linearly moves when the rotating member rotates;
a meshing portion that meshes with the rotary member when the linear motion member linearly moves;
and an elastic member that stores elastic energy when the rotating member and the meshing portion rotate together in a state where the rotating member and the meshing portion are meshed.