WO2017006956A1

WO2017006956A1 - Device for driving power brake

Info

Publication number: WO2017006956A1
Application number: PCT/JP2016/069979
Authority: WO
Inventors: 利史前原
Original assignee: 曙ブレーキ工業株式会社
Priority date: 2015-07-09
Filing date: 2016-07-06
Publication date: 2017-01-12
Also published as: JP2017020564A

Abstract

In a device (11) for driving a power brake, power from an electric motor (17) is delivered to a final output gear (19) via a coaxially disposed reduction mechanism (13) and is outputted, via an output gear (21) that meshes with the final output gear (19), to a thrust-generating mechanism (23) offset from the electric motor (17). The output gear (21) is disposed between the electric motor (17) and the reduction mechanism (13).

Description

Electric brake drive device

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

A motor gear unit (MGU) expands a pair of brake shoes to both sides and presses against a brake drum that rotates with the wheels to generate a braking force (see Patent Document 1) or a hydraulic cylinder as a motor An electric disc brake (see Patent Document 2) that presses a pair of brake pads against both side surfaces of a rotor with an electric caliper replaced with a gear unit (MGU) is known as an electric brake for automobiles, trains, and the like.

A motor gear unit in a motor-driven drum brake disclosed in Patent Document 1 (which can be referred to as an “electric drum brake”) is a rotation disposed so as to be movable in the axial direction and rotatable about an axis. The slide member is rotated via the input gear in accordance with the brake rotation of the electric motor. This rotation moves a pair of projecting members screwed to the rotating slide member via a pair of opposite screw mechanisms in a direction protruding from the rotating slide member. Thus, the electric drum brake opens the pair of brake shoes and presses them against the brake drum.

Further, an electric disk brake device disclosed in Patent Document 2 includes a rotor that rotates together with wheels, a carrier that is fixed to a vehicle body side, a pair of brake pads that are disposed on both sides of the rotor and supported by the carrier, and a rotor And an electric caliper supported on the carrier so as to be movable along the axial direction of the rotor. The electric caliper is a caliper body in which a motor gear unit including an electric motor, a speed reduction mechanism, a rotation-linear motion conversion mechanism, and a piston is incorporated. During braking, the rotation / linear motion conversion mechanism is driven by the rotation of the electric motor through the speed reduction mechanism, and one brake pad is pressed against the rotor by the piston, and the caliper body is moved by the reaction force of the pressing by the piston. Then, braking is performed by pressing the other brake pad against the rotor, and the braking is released by rotating the electric motor in reverse to separate the brake pad from the rotor.

Japanese Unexamined Patent Publication No. 2001-12521 Japanese Unexamined Patent Publication No. 2009-287732

However, in a conventional electric drum brake, a motor gear unit (hereinafter also referred to as MGU) is generally fastened and fixed to a backing plate. For this reason, in the electric drum brake, when the MGU is arranged inside the backing play rod, it is necessary to coexist with a portion that receives the anchor force of the brake shoe. As a result, in the conventional electric drum brake, when the brake size is reduced, it may be difficult to arrange the MGU.
Further, in the conventional electric disc brake, since the structure in which the MGU is mounted on the inner side end of the caliper is common, the weight on the inner side of the caliper increases. As a result, the weight balance with respect to the caliper sliding portion deteriorates, and vibrations may occur, which may adversely affect caliper holding and sliding performance.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a drive device for an electric brake that has a good layout and can be applied to a small brake.

The above object of the present invention is achieved by the following configuration.
(1) The power from the electric motor is input to the final output gear via a coaxially arranged reduction mechanism, and is offset from the electric motor via an output gear meshing with the final output gear. A driving device for an electric brake that is output to a thrust generation mechanism, wherein the output gear is disposed between the electric motor and the speed reduction mechanism.

According to the electric brake driving device having the configuration (1), in the electric brake mechanism that performs braking by the electric motor and the speed reduction mechanism, the output gear is arranged between the electric motor and the speed reduction mechanism, thereby improving the layout. And it is easy to place in a small brake. That is, the electric motor and the speed reduction mechanism are arranged in series, and the output of the speed reduction mechanism is configured to be between the electric motor and the speed reduction mechanism. In a reduction gear that combines a reduction mechanism (planetary gear mechanism) and an output gear (spur gear), the output gear is generally composed of a spur gear having a larger diameter or a multi-stage spur gear than the planetary gear mechanism. is there. In other words, the planetary gear mechanism and the electric motor have a smaller diameter than a large-diameter spur gear or a multi-stage spur gear. By arranging the output gear configured to have a large diameter between the planetary gear mechanism having a small diameter and the electric motor, the layout when incorporated into a small brake is improved, and the arrangement becomes easy.

(2) The thrust generating mechanism is disposed between one adjacent ends of a pair of brake shoes disposed so as to face the inner peripheral surface of the brake drum and movably supported by a backing plate. The electric brake driving device according to (1), wherein each of the brake shoes is expanded.

According to the electric brake driving device having the configuration (2), the output gear (spur gear), which is the large diameter portion, can be disposed between the two brake shoes. The electric motor and the planetary gear mechanism, which are small-diameter portions, can be disposed between the brake shoe web and the backing plate. As a result, the thrust generating mechanism can be easily applied to a small electric drum brake.

(3) The thrust generation mechanism is disposed on an inner side of the inner pad and an outer pad disposed in a state of being opposed to the axial side surface of the rotor, and the inner pad and the outer pad are respectively disposed in the axial direction of the rotor. The drive device for an electric brake according to (1), wherein the drive device is pressed against a side surface.

According to the electric brake driving device having the configuration (3), the thrust generating mechanism is disposed on the inner side of the inner pad. The thrust generating mechanism is offset from the electric motor. The output from the electric motor is transmitted to the thrust generating mechanism by an output gear disposed between the electric motor and the speed reduction mechanism. The electric disc brake moves the caliper with respect to the support in the axial direction of the rotor, and presses the inner pad and the outer pad against the axial side surface of the rotor, respectively. In the electric disc brake, the weight on both ends in the moving direction of the caliper does not increase because the thrust generating mechanism is offset from the electric motor. As a result, the caliper suppresses the deterioration of the weight balance with respect to the sliding portion, improves the layout property and hardly causes vibration.

(4) The thrust generating mechanism is based on a combination of a nut member that can rotate integrally with the output gear and that can move relative to the axial direction, and a projecting screw arranged coaxially with the nut member. The projecting screw includes a first projecting member having a first projecting end portion at one end and a male threaded portion at the other end, a second projecting end portion at one end, and a fitting shaft at the other end. And a male threaded portion of the first projecting member is screwed into a female threaded portion at one end of the nut member, and the second projecting member is fitted into a fitting hole at the other end of the nut member. The drive device for an electric brake according to (1) or (2), wherein a fitting shaft portion of the member is rotatably fitted.

According to the electric brake driving device having the configuration (4), when the nut member is rotated by the output gear, the second projecting member fitted in the fitting hole of the nut member rotates relative to the nut member (that is, , Do not rotate). On the other hand, since the first projecting member is screwed to the nut member by the female screw portion and the male screw portion, the first projecting member moves away from the second projecting member in the direction along the axis. Accordingly, the first projecting member and the second projecting member are moved (projected) in a direction in which the first projecting end portion and the second projecting end portion are separated from each other, and the pair of brake shoes of the electric drum brake can be expanded. it can.

(5) The thrust generation mechanism is configured by a combination of a feed screw mechanism and a high-efficiency axial force conversion mechanism, and the feed screw mechanism is driven via a transmission gear that is rotated by the output gear. As a drive spindle, a drive-side rotor screwed into an external thread portion provided on an outer half of the drive spindle, and a thrust bearing interposed between an inner-side end of the drive spindle and an inner-side end of the caliper And the high-efficiency axial force conversion mechanism includes the driving-side rotor, the driven-side rotor, and a rolling element interposed between the driving-side rotor and the driven-side rotor, The drive device for an electric brake according to (1) or (3), wherein the drive spindle is movable relative to the output gear in the axial direction and capable of transmitting rotational force.

According to the electric brake driving device having the configuration (5), when the electric motor is driven, the driving spindle that meshes with the output gear is rotated. When the drive spindle is rotated, the drive-side rotor moves in parallel with the driven-side rotor toward the front end side of the drive spindle. By this parallel movement, the inner pad is pushed out and pressed against the rotor.
When the resistance against the further movement of the driving side rotor and the driven side rotor toward the rotor increases, the driving side rotor and the driven side rotor rotate relative to each other. Then, the rolling element moves while rolling, and the interval between the drive-side rotor and the driven-side rotor increases.
As the distance between the drive-side rotor and the driven-side rotor increases, the main body wall portion of the caliper provided on the side opposite to the inner pad moves in a direction away from the inner pad. Accordingly, the caliper presses the outer pad against the rotor, and each of the inner pad and the outer pad is pressed against the side surface in the axial direction of the rotor.

(6) The electric brake driving device according to any one of (1) to (5), wherein the speed reduction mechanism includes at least one planetary gear mechanism.

According to the electric brake driving apparatus having the configuration (6), the reduction mechanism includes the planetary gear mechanism, so that a large reduction ratio can be obtained in a small arrangement space.

(7) The first planetary gear meshing with the gear housing that defines the gear housing space, the input gear shaft that is rotationally driven by the electric motor, and the first sun gear that rotates integrally with the input gear shaft. A gear, a first planet carrier that holds the first planetary gear around the first sun gear, and a first planetary gear that is formed on an inner peripheral surface of the gear housing and meshes with the first planetary gear. An internal tooth, a second sun gear that is disposed on the electric motor side with respect to the first sun gear, and rotates together with the first planet carrier; and a second planet gear that meshes with the second sun gear; A second planetary carrier that holds the second planetary gear around the second sun gear so as to freely rotate and revolve, and a second inner tooth that is formed on the inner peripheral surface of the gear housing and meshes with the second planetary gear. And the second sun gear A final output gear that is disposed on the electric motor side and is driven to rotate by the second planet carrier, and an output gear that meshes with the final output gear and is rotatable about a rotation axis parallel to the input gear shaft. And the electric brake drive device according to (6).

According to the electric brake driving device having the configuration (7), the high-speed rotation from the electric motor is decelerated at a large reduction ratio by the two-stage planetary gear mechanism connected in series and transmitted to the final output gear. . The rotation of the final output gear is transmitted to the output gear, and finally input from the output gear to the thrust generating mechanism. The output gear is disposed between the speed reduction mechanism having the planetary gear mechanism and the electric motor. That is, the electric brake driving device of this configuration inputs power to the thrust generating mechanism via the output gear from the central position of the motor gear unit in which the speed reduction mechanism and the electric motor are connected in series. That is, in the electric brake, the motor gear unit that is offset with respect to the thrust generation mechanism is disposed at the center position of the thrust generation mechanism. As a result, the drive device for the electric brake has the effects of improving the assembly property to the small electric drum brake and suppressing the deterioration of the weight balance with respect to the caliper sliding portion of the electric disc brake.

The electric brake driving device according to the present invention has good layout and can be applied to a small brake.

The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

FIG. 1A is a perspective view of the electric brake driving device according to the first embodiment of the present invention, and FIG. 1B is a diagram illustrating the electric brake driving device of FIG. It is the disassembled perspective view isolate | separated into the mechanism side. FIG. 2 is an exploded perspective view of a speed reduction mechanism in the electric brake driving device shown in FIG. 3A is a side view of the electric brake driving device shown in FIG. 1A viewed from the speed reduction mechanism side, and FIG. 3B is a cross-sectional view taken along line AA in FIG. 3A. It is. FIG. 4 is a perspective view of the gear housing shown in FIG. FIG. 5 is a perspective view of an electric drum brake to which the electric brake driving device shown in FIG. 6 is a plan view of the electric drum brake shown in FIG. 7 is a cross-sectional view taken along the line BB of FIG. FIG. 8 is a side view of the electric drum brake shown in FIG. 9 is a cross-sectional view taken along the line CC of FIG. FIG. 10 is a perspective view of another electric drum brake to which the electric brake driving device shown in FIG. 11 (a) is a plan view of the electric drum brake shown in FIG. 10, and FIG. 11 (b) is a side view of FIG. 11 (a). FIG. 12 is a plan view in which a part of the electric drum brake shown in FIG. FIG. 13 is a longitudinal sectional view of an electric disc brake to which an electric brake driving device according to a second embodiment of the present invention is applied. 14 is a DD cross-sectional view of the electric disc brake shown in FIG.

Embodiments according to the present invention will be described below with reference to the drawings.
As shown in FIG. 1 to FIG. 3B, the electric brake driving device 11 according to the first embodiment of the present invention is applied to an electric drum brake 79 described later. The electric brake driving device 11 according to the first embodiment can also be applied to an electric drum brake 131 described later.
As shown in FIGS. 3A and 3B, the electric brake drive device 11 according to the first embodiment is powered by a reduction mechanism 13 arranged coaxially. It is input to the output gear 19 and output to a thrust generating mechanism 23 that is offset with respect to the electric motor 17 via an output gear 21 that meshes with the final output gear 19. The output gear 21 is disposed between the electric motor 17 and the speed reduction mechanism 13.

In the electric brake drive device 11, the speed reduction mechanism 13 has at least one planetary gear mechanism. The planetary gear mechanism in the speed reduction mechanism 13 of the present embodiment includes a first planetary gear unit 25 and a second planetary gear unit 27 as shown in FIG.

The electric brake driving device 11 includes a motor gear housing 29. The motor gear housing 29 includes a gear housing 15 that defines a gear housing space and houses the speed reduction mechanism 13, and a motor housing 31 that houses the electric motor 17 and is integrally fixed by a housing fastening bolt 33.
The gear housing 15 in the motor gear housing 29 includes a bottomed cylindrical reduction mechanism accommodating portion 16 that accommodates the reduction mechanism 13 and a gear accommodating portion 18 in which the first projecting member insertion hole 52 is formed so as to penetrate the output gear 21. And have. The motor housing 31 in the motor gear housing 29 includes a bottomed cylindrical motor housing portion 32 that houses the electric motor 17, and a second projecting member insertion hole 54 formed through the nut member 35 of the thrust generating mechanism 23. And a nut member accommodating portion 34 in which the inserted spacer 37 is accommodated.

The thrust generating mechanism 23 corresponds to an electric drum brake. That is, as shown in FIG. 3B, the thrust generating mechanism 23 includes a nut member 35 that can rotate integrally with the output gear 21 and that can move relative to the axial direction. The screw mechanism is configured by a combination with the protruding screw 39 arranged coaxially. The protruding screw 39 includes a first protruding member 45 having a first protruding end portion 41 at one end and a male screw portion 43 at the other end, a second protruding end portion 47 at one end, and a fitting shaft portion 49 at the other end. The male threaded portion 43 of the first projecting member 45 is screwed into the female threaded portion 53 at one end of the nut member 35, and the fitting hole 55 at the other end of the nut member 35 is The fitting shaft portion 49 of the two projecting members 51 is rotatably fitted.

The nut member 35 moves relative to the first gear shaft 57 in the axial direction. That is, a pair of slide protrusions (not shown) protruding from the outer peripheral surface of the nut member 35 is engaged with guide grooves (not shown) formed along the axial direction on the inner peripheral surface of the first gear shaft 57. Thus, the nut member 35 can rotate integrally with the first gear shaft 57 and can be relatively moved in the axial direction. The nut member 35 can also be configured to be rotatable integrally with the first gear shaft 57 by spline fitting or the like and to be relatively movable in the axial direction.

In the protruding screw 39 of the present embodiment, the male threaded portion 43 of the first projecting member 45 is screwed into the female threaded portion 53 at one end of the nut member 35, and the second projecting member 51 is inserted into the fitting hole 55 at the other end of the nut member 35. The fitting shaft portion 49 is rotatably fitted. Therefore, the protruding screw 39 converts the rotation of the nut member 35 that rotates integrally with the first gear shaft 57 into a linear motion by a screw mechanism. Accordingly, the projecting screw 39 moves the first projecting end 41 and the second projecting end 47 which are both ends projecting from the gear housing 15 forward and backward, so that the first brake shoe and the second brake shoe described later are moved. One adjacent end is expanded.

In the speed reduction mechanism accommodating portion 16 of the gear housing 15, there are an input gear shaft 59, a first sun gear 61, a first planetary gear 63, a first planet carrier 65, a first inner tooth 67, and a second sun A reduction mechanism 13 including a gear 69, a second planetary gear 71, a second planet carrier 73, a second internal tooth 75, and a final output gear 19 is provided.

The input gear shaft 59 is rotationally driven by the output shaft 77 of the electric motor 17. The input gear shaft 59 rotates integrally with the first sun gear 61. The first sun gear 61 meshes with the first planetary gear 63. The first planetary gear 63 is held by the first planetary carrier 65 so as to be able to rotate and revolve around the first sun gear 61. First internal teeth 67 are formed on the inner peripheral surface of the speed reduction mechanism accommodating portion 16 in the gear housing 15 (see FIG. 4). The first internal teeth 67 mesh with the first planetary gear 63.

The second sun gear 69 is disposed on the electric motor 17 side with respect to the first sun gear 61. The second sun gear 69 rotates integrally with the first planet carrier 65. The second sun gear 69 meshes with the second planetary gear 71. The second planetary gear 71 is held by the second planetary carrier 73 so as to freely rotate and revolve around the second sun gear 69. Second internal teeth 75 are formed on the inner peripheral surface of the speed reduction mechanism accommodating portion 16 in the gear housing 15 (see FIG. 4). The second internal teeth 75 mesh with the second planetary gear 71.

The final output gear 19 is disposed on the electric motor 17 side with respect to the second sun gear 69. The final output gear 19 is rotationally driven by the second planet carrier 73.

With the above-described configuration, the speed reduction mechanism 13 uses a planetary gear mechanism including a two-stage first planetary gear unit 25 and a second planetary gear unit 27 connected to the high-speed rotation from the output shaft 77 of the electric motor 17 in series. The vehicle is decelerated at a large reduction ratio and transmitted to the final output gear 19. The rotation of the final output gear 19 is transmitted to the output gear 21 and is finally input from the output gear 21 to the thrust generating mechanism 23.

Next, the operation of the above configuration will be described.
In the electric brake drive device 11 according to the first embodiment, in the electric brake mechanism that performs braking by the electric motor 17 and the speed reduction mechanism 13, the output gear 21 is disposed between the electric motor 17 and the speed reduction mechanism 13. As a result, the layout is improved and the arrangement in the small brake becomes easy. That is, the electric motor 17 and the speed reduction mechanism 13 are arranged in series, and the output of the speed reduction mechanism 13 is configured to be between the electric motor 17 and the speed reduction mechanism 13. In the speed reduction device in which the speed reduction mechanism 13 (planetary gear mechanism) and the output gear 21 (spur gear) are combined, the output gear 21 has a larger diameter than the speed reduction mechanism 13. In other words, the speed reduction mechanism 13 and the electric motor 17 have a smaller diameter than the output gear 21 that is a large-diameter spur gear. By arranging the output gear 21 having a large diameter between the reduction mechanism 13 having a small diameter and the electric motor 17, a layout for incorporating into a small electric drum brake is facilitated.

Further, in the electric brake drive device 11 of the first embodiment, since the speed reduction mechanism 13 includes the planetary gear mechanism, a large speed reduction ratio can be obtained in a small arrangement space.

In the electric brake driving device 11 of the first embodiment, the high-speed rotation from the electric motor 17 is reduced at a large reduction ratio by the two-stage planetary gear mechanism connected in series and transmitted to the final output gear 19. Is done. The rotation of the final output gear 19 is transmitted to the output gear 21 and finally input from the output gear 21 to the thrust generating mechanism 23. The output gear 21 is disposed between the speed reduction mechanism 13 having the planetary gear mechanism and the electric motor 17. That is, the electric brake driving device 11 of the first embodiment transmits power to the thrust generating mechanism 23 from the central position of the motor gear unit in which the speed reduction mechanism 13 and the electric motor 17 are connected in series via the output gear 21. input. That is, in the electric drum brake, the motor gear unit that is offset with respect to the thrust generating mechanism 23 is disposed at the center position of the thrust generating mechanism 23. As a result, the electric brake driving device 11 has an effect of improving the assembling property to a small electric drum brake.

Next, an electric drum brake 79 to which the electric brake driving device 11 according to the first embodiment is applied will be described.
5 is a perspective view of the electric drum brake 79 to which the electric brake driving device 11 shown in FIG. 1A is applied, FIG. 6 is a plan view of the electric drum brake 79 shown in FIG. 5, and FIG. 6 is a sectional view taken on line BB of FIG. 6, FIG. 8 is a side view of the electric drum brake 79 shown in FIG. 6, and FIG. 9 is a sectional view taken on line CC of FIG. In the present embodiment, the same members as those of the electric brake driving device 11 shown in FIGS. 1 to 4 are denoted by the same reference numerals.
An electric drum brake 79 shown in FIGS. 5 to 9 includes the electric brake driving device 11 according to the first embodiment of the present invention. The electric brake drive device 11 includes an electric motor 17 that is a drive source, a speed reduction mechanism 13, and the thrust generation mechanism 23 that converts rotation transmitted through the speed reduction mechanism 13 into linear motion.

In this electric drum brake 79, a pair of thrust generating mechanisms 23 in the electric brake driving device 11 are arranged so as to face an inner peripheral surface of a brake drum (not shown) and supported by a backing plate 81 so as to be movable. The brake shoe is interposed between one adjacent ends of the brake shoes to expand each of the pair of brake shoes.

The electric drum brake 79 provided with the electric brake driving device 11 operates as a leading / trailing (LT) type at the time of service braking by the operation of the wheel cylinder 83 when the foot brake pedal is depressed, and the electric motor 17 when the parking switch is operated. When the parking brake is activated, the dual mode structure that operates as a duo servo (DS) type is adopted. The electric drum brake 79 includes a first brake shoe 85 and a second brake shoe 87, a wheel cylinder 83 interposed between the other adjacent ends of the first brake shoe 85 and the second brake shoe 87, and a first brake shoe. The drive device 11 of the electric brake interposed between one adjacent end of 85 and the 2nd brake shoe 87 is comprised as a main member.

The electric drum brake 79 is integrally fixed to the vehicle body in such a posture that the backing plate 81 is substantially perpendicular to the rotational axis of the wheel (not shown). On the backing plate 81, a first brake shoe 85 and a second brake shoe 87, which are a pair of brake shoes each having a substantially arc shape, are arranged vertically along the left and right outer peripheral edges.

The first brake shoe 85 and the second brake shoe 87 are disposed so as to face the inner peripheral surface of the brake drum. The first brake shoe 85 and the second brake shoe 87 are elastically supported by the first shoe hold device 89 and the second shoe hold device 91 so as to be movable, and can be expanded. The first brake shoe 85 and the second brake shoe 87 are elastically urged in a direction approaching each other by a pair of first shoe return spring 93 and second shoe return spring 95.

A wheel cylinder 83 as a fluid actuator is interposed between the other adjacent ends of the first brake shoe 85 and the second brake shoe 87 in the upper part of FIG. The wheel cylinder 83 is attached to the backing plate 81, and the first and

second brake shoes

85 and 87 are expanded by pushing the first piston 97 and the second piston 99 away from one adjacent end in a separating direction. Let
One adjacent end of the first brake shoe 85 and the second brake shoe 87 in the lower part of FIG. 6 is brought into contact with the anchor portion 101 and the anchor portion 103 of the gear housing 15 attached to the backing plate 81. That is, the gear housing 15 fixed to the backing plate 81 has the anchor portion 101 and the anchor portion 103 with which one adjacent end of the pair of brake shoes abuts.

The motor gear housing 29 is fixed to the backing plate 81 by four first fastening bolts 105, second fastening bolts 107, third fastening bolts 109, and fourth fastening bolts 111. Among these, the 1st fastening bolt 105 and the 4th fastening bolt 111 are comprised so that it may serve as the ledge surface of a brake shoe. The electric drum brake 79 is configured such that the first fastening bolt 105 and the fourth fastening bolt 111 for attaching the motor gear housing 29 to the backing plate 81 are configured as a ledge surface for holding the brake shoe. The aperture shape of the plate 81 is simplified and the manufacture becomes easy.

When the service brake is performed by depressing the foot brake pedal, the wheel cylinder 83 is pressurized and actuated by the first cylinder 97 and the second piston 99 that advance from both ends of the wheel cylinder 83, thereby the first brake shoe 85 and the second brake. The shoe 87 is expanded and rotated from the position of FIG. 6 around the contact point with the anchor portion 101 and the anchor portion 103. As a result, the first brake shoe 85 and the second brake shoe 87 are frictionally engaged with the inner peripheral surface of the brake drum to brake it. At this time, one of the first brake shoe 85 and the second brake shoe 87 is a leading shoe with respect to the rotation direction of the brake drum and has a self-servo property, and the other is a trailing shoe with respect to the rotation direction of the brake drum. Therefore, the drum brake device acts as a leading / trailing drum brake. When the service brake is applied with the vehicle backed, the opposite action is obtained, so the same braking action can be obtained.

Between the adjacent ends of the first brake shoe 85 and the second brake shoe 87 in the vicinity of the wheel cylinder 83, an adjuster 113 for adjusting the shoe interval is interposed. The adjuster 113 is provided with a shoe gap automatic adjusting mechanism, and can be expanded and contracted in the axial direction by an adjuster screw 115.

The adjustment lever 117 is pivotally supported on the first web 121 of the first brake shoe 85 by the first fulcrum pin 119. A first shoe return spring 93 is stretched between the adjustment lever 117 and the second brake shoe 87, and urges the adjustment lever 117 to rotate counterclockwise in FIG. Further, the arm portion of the adjustment lever 117 is rotationally engaged with the toothed wheel 123 of the adjuster 113 by this rotation biasing force. The toothed ring 123 is rotated by the arm portion.

The one end side of the adjuster screw 115 is inserted into the adjuster socket 125. The other end side (the right end side in FIG. 6) of the adjuster screw 115 whose one end is inserted into the adjuster socket 125 is an engagement plate portion 127. The adjuster socket 125 is in contact with the first web 121 of the first brake shoe 85. The engagement plate portion 127 is in contact with the second web 129 of the second brake shoe 87.

The standby positions of the first brake shoe 85 and the second brake shoe 87 during non-braking are adjusted by the first shoe return spring 93 disposed across the first brake shoe 85 and the second brake shoe 87. 113 is defined by the overall length. The adjuster 113 makes the shoe gaps between the first brake shoe 85 and the second brake shoe 87 and the brake drum substantially constant regardless of the wear of the friction material (lining). The standby positions of the brake shoe 85 and the second brake shoe 87 are changed.

That is, when the movement amount of the first brake shoe 85 and the second brake shoe 87 during braking increases due to wear of the friction material, the toothed wheel 123 is rotated by the adjustment lever 117. The adjuster screw 115 screwed into the toothed ring 123 is advanced and retracted with respect to the adjuster socket 125. As a result, the adjuster 113 has a longer overall length, the standby positions of the first brake shoe 85 and the second brake shoe 87 during non-braking are separated, and the shoe gap (the total dimension of the shoe gaps on both sides) is substantially constant. Maintained.

Next, the operation of the above configuration will be described.
In the electric brake driving device 11 in the electric drum brake 79 described above, the projecting screw 39 expands each of the first brake shoe 85 and the second brake shoe 87 by rotating the nut member 35 by the electric motor 17. Let Therefore, at the time of parking brake, the first brake shoe 85 and the second brake shoe 87 are expanded on the motor gear housing 29 side by the first projecting member 45 and the second projecting end 47 of the projecting screw 39 projecting from the gear housing 15. The braking force is generated by being pressed against the inner peripheral surface of the brake drum. Further, even during service braking, a part of the brake reaction force acts on the drum sliding surface via the projecting screw 39, and the brake reaction force acting on the anchor portion 101 and the anchor portion 103 of the gear housing 15 is reduced.

Therefore, the electric brake drive device 11 having the above-described configuration for expanding the first brake shoe 85 and the second brake shoe 87 during parking brake is provided between the adjacent ends of one of the first brake shoe 85 and the second brake shoe 87. Is disposed in the motor gear housing 29 fixed to the backing plate 81, so that the anchor portion 101 receiving the reaction force of the brake and the anchor portion 103 can coexist with the expansion mechanism, and a small brake In terms of size, the arrangement of the electric brake driving device 11 is facilitated.

Further, in the thrust generating mechanism 23, the nut member 35 disposed coaxially in the first gear shaft 57 of the gear unit rotated by the electric motor 17 has a first brake shoe 85 and a second brake shoe 87 at the time of braking. Therefore, a load that impairs durability is not generated between the protruding screw 39 and the screw portion (the male screw portion 43 and the female screw portion 53).
Therefore, the thrust generating mechanism 23 is less susceptible to the brake reaction force from the first brake shoe 85 and the second brake shoe 87, the gear meshing portion does not slip, and the durability of the gear tooth surface is not impaired. Can be realized.

In the electric brake driving device 11, the output gear 21 (spur gear) that is a large diameter portion can be disposed between the two first brake shoes 85 and the second brake shoes 87. The electric motor 17 and the speed reduction mechanism 13, which are small-diameter portions, can be disposed between the first and

second webs

121 and 129 of the first and

second brake shoes

85 and 87 and the backing plate 81. As a result, the thrust generating mechanism 23 can be easily applied to the small electric drum brake 79.

In the electric brake driving device 11 in the electric drum brake 79, when the nut member 35 is rotated by the output gear 21, the second projecting member 51 fitted in the fitting hole 55 of the nut member 35 rotates relative to the nut member 35. Do (ie do not rotate). On the other hand, since the first projecting member 45 is screwed to the nut member 35 by the female threaded portion 53 and the male threaded portion 43, the first projecting member 45 moves away from the second projecting member 51 in the direction along the axis. To do. Accordingly, the first projecting member 45 and the second projecting member 51 are moved (projected) in the direction in which the first projecting end portion 41 and the second projecting end portion 47 are separated from each other, and the first brake shoe 85 of the electric drum brake 79 is moved. And the 2nd brake shoe can be expanded.

Next, an electric drum brake 131 to which the electric brake driving device 11 according to the first embodiment is applied will be described.
10 is a perspective view of another electric drum brake 131 to which the electric brake driving device 11 shown in FIG. 1A is applied, and FIG. 11A is a plan view of the electric drum brake 131 shown in FIG. 11 (b) is a side view of FIG. 11 (a), and FIG. 12 is a plan view in which a part of the electric drum brake 131 shown in FIG. 11 (a) is cut away. In the present embodiment, the same members as those shown in FIGS. 1 to 9 are denoted by the same reference numerals.
In the electric drum brake 131 shown in FIGS. 10 to 12, the electric brake driving device 11 is also used for a service brake. The electric drum brake 131 is integrally fixed to the vehicle body in such a posture that the backing plate 81 is substantially perpendicular to the rotational axis of a wheel (not shown). On the backing plate 81, a first brake shoe 85 and a second brake shoe 87, which are a pair of brake shoes each having a substantially arc shape, are arranged vertically along the left and right outer peripheral edges.

The first brake shoe 85 and the second brake shoe 87 are elastically supported by the first shoe hold device 89 and the second shoe hold device 91 so as to be movable and can be expanded. It becomes. The first brake shoe 85 and the second brake shoe 87 are urged in a direction approaching each other by the pair of first shoe return springs 93 and second shoe return springs 95.

12, an electric brake driving device 11 is interposed at the adjacent ends of the first brake shoe 85 and the second brake shoe 87 in the upper part of FIG. The electric brake driving device 11 is attached to the backing plate 81, and the first projecting member 45 and the second projecting member 51 can push the adjacent ends away from each other, whereby the first brake shoe 85 and the second brake shoe are driven. It is comprised so that 87 can be expanded. The adjacent ends of the first brake shoe 85 and the second brake shoe 87 in the lower part of FIG. 12 are brought into contact with fixed anchor portions 133 attached to the backing plate 81, respectively.

At the time of service braking by depressing the foot brake pedal, the electric brake driving device 11 in the electric drum brake 131 is operated and the first and

second brake members

85 and 51 are advanced by the first protruding member 45 and the second protruding member 51 that advance from both ends thereof. The two brake shoes 87 expand and rotate from the position shown in FIG. 12 around the contact point with the anchor portion 133. As a result, the first brake shoe 85 and the second brake shoe 87 are frictionally engaged with an inner peripheral surface of a brake drum (not shown) to brake it. At this time, one of the first brake shoe 85 and the second brake shoe 87 is a leading shoe with respect to the rotation direction of the brake drum and has a self-servo property, and the other is a trailing shoe with respect to the rotation direction of the brake drum. Therefore, the electric drum brake 131 acts as a leading / trailing type. The operation of the electric drum brake 131 during the parking brake of the electric brake driving device 11 is the same as that during the service brake.
As described above, the electric brake driving device 11 can also correspond to the electric drum brake 131 applied as a service brake driving source.

Next, a floating electric disc brake 135 to which the electric brake driving device 137 according to the second embodiment of the present invention is applied will be described.
FIG. 13 is a longitudinal sectional view of a floating electric disc brake 135 to which an electric brake driving device 137 according to a second embodiment of the present invention is applied, and FIG. 14 is a D-of the floating electric disc brake 135 shown in FIG. It is D sectional drawing. In the present embodiment, the same members as those shown in FIGS. 1 to 4 are denoted by the same reference numerals.
The floating electric disc brake 135 shown in FIGS. 13 and 14 includes an electric brake driving device 137 according to the second embodiment of the present invention. The electric brake drive device 137 is different from the electric brake drive device 11 according to the first embodiment in a thrust generation mechanism 139. Other configurations (such as the speed reduction mechanism 13) are the same as those of the driving device 11 for the electric brake. The electric brake driving device 137 in the floating electric disc brake 135 is disposed on the inner side of the inner pad 143 in the inner pad 143 and the outer pad 145 in which the thrust generating mechanism 139 is disposed in a state of facing the axial side surface of the rotor 141. Then, the inner pad 143 and the outer pad 145 are pressed against the side surface of the rotor 141 in the axial direction.

The support 147 is fixed to the vehicle body (not shown) adjacent to the rotor 141 that rotates together with the wheels (not shown). In the present embodiment, the support 147 is disposed facing the inner surface of the rotor 141. The support 147 is formed in a substantially rectangular plate shape, and a pair of

arm portions

149 and 149 are provided on both the turn-in side and the turn-out side of the rotor 141 that are both ends of one long side portion.

A pin insertion hole 151 is formed in each of the pair of

arm portions

149 and 149. This pin insertion hole 151 is for inserting a slide pin 167 described later. The slide pin 167 is fixed to the support 147 via a sleeve 165 described later. The support 147 is formed with a pair of mounting holes (not shown) at positions closer to the center of the rotor than the pin insertion holes 151 (both ends of the other long side portion). The support 147 is fixed to the vehicle body by inserting mounting screws (not shown) through the pair of mounting holes. An inner pad 143 to be described later is attached to the support 147 while being guided so as to be movable in the axial direction of the rotor 141.

The caliper 153 has a main body wall portion 155 (an inner side end of the caliper 153) disposed on the inner side of the bridge portion 159 straddling the rotor 141, and a claw portion 157 disposed on the outer side so as to be connected integrally. To be formed. The caliper 153 is supported by the support 147 so as to be movable along the axial direction of the rotor 141 by the pair of left and right parallel sleeves 165 (described later).

The caliper 153 is formed with a pair of

cylindrical portions

161 and 161 on the outer side of the bridge portion 159 with the axis line along the axial direction of the rotor 141. In the pair of

cylinder portions

161 and 161, a hole penetrating along the axis is a sleeve insertion hole 163. The sleeve 165 is inserted into the sleeve insertion hole 163 of each cylindrical portion 161. The slide pin 167 is inserted into the sleeve 165 from the inner side. The slide pin 167 protrudes from the sleeve 165 at the tip, and penetrates a pair of mounting

portions

171 and 171 of a cylinder body 169 described later. The slide pin 167 penetrating the pair of

attachment portions

171 and 171 protrudes from the pin insertion hole 151 of the support 147. A torque receiving pin 173 is screwed to the tip of the slide pin 167 protruding from the pin insertion hole 151 of the support 147. That is, the sleeve 165, the pair of

attachment portions

171, 171, and the pair of

arm portions

149, 149 are fixed in a state of being sandwiched integrally by the pin head 175 and the torque receiving pin 173.

The sleeve 165 is fixed to the support 147 by the slide pin 167 as described above. In the caliper 153, the sleeve 165 is slidably inserted into the sleeve insertion holes 163 of the

cylindrical portions

161 and 161. Further, the torque receiving pin 173 screwed to the tip of the slide pin 167 is slidably inserted into a pin engagement hole 177 formed in the claw portion 157 of the caliper 153. As a result, the caliper 153 has the cylindrical portion 161 slidably supported by the sleeve 165 and the torque receiving pin 173 that are integrally fixed to the support 147. The outer peripheral surface of the sleeve 165 on which the pair of

cylindrical portions

161 and 161 slide is covered with

sleeve boots

179 and 181 to be dust-proof.

Thus, the caliper 153 straddling the rotor 141 is movable along the axial direction of the rotor 141 via the pair of left and right parallel sleeves 165 with respect to the support 147 attached to the vehicle body.

The inner pad 143 is disposed on the inner side of the rotor 141 and is guided by the support 147 so as to be movable in the axial direction of the rotor 141. The inner pad 143 has, for example, anchor protrusions (not shown) on both side edges, and a concave groove (not shown) along the rotor shaft direction is formed in a corresponding portion of the support 147. Part. By operating the electric motor 17 of the electric brake driving device 137, the inner pad 143 moves while being guided by the concave and convex fitting portion by a thrust generation mechanism 139 described later, and is pressed against the rotor 141 to follow the rotor 141. When trying to rotate, the concave-convex fitting portion functions as an anchor and receives braking torque.

The outer pad 145 is disposed on the outer side of the rotor 141 and is held by the claw portion 157. The caliper 153 is guided by the sleeve 165 and moved toward the inner side along the axial direction of the rotor 141 by the pressing reaction force of the inner pad 143. That is, the claw portion 157 of the caliper 153 approaches the rotor 141. As a result, the outer pad 145 is pressed against the rotor 141 by the claw portion 157. The braking torque of the outer pad 145 is transmitted to the caliper 153 via the sleeve 165 and the torque receiving pin 173, and is further transmitted to the support 147.

The caliper 153 is moved along the axial direction of the rotor 141 by the thrust generating mechanism 139 of the electric brake driving device 137. The thrust generating mechanism 139 is interposed between the inner pad 143 and the main body wall portion 155. The thrust generating mechanism 139 expands the space between the inner pad 143 and the main body wall portion 155 by the power from the electric motor 17 of the electric brake driving device 137, so that the inner pad 143 and the outer pad 145 are respectively connected to the shaft of the rotor 141. Press on the direction side.

A cylinder body 169 and a motor gear housing 29 that are integrally fixed are disposed inside the caliper 153. The cylinder body 169 and the motor gear housing 29 are fixed to the support 147 via a pair of mounting

portions

171 and 171 of the cylinder body 169.

The cylinder body 169 has both ends opened on the inner pad side and the main body wall side of the caliper 153. In the cylinder body 169, the inner pad side piston 183 advances and retreats. The outer periphery of the inner pad side piston 183 protruding from the inner pad 143 side of the cylinder body 169 is covered with an inner pad side piston boot 185 to be dust-proof.

The gear housing 15 in the motor gear housing 29 includes a bottomed cylindrical reduction mechanism accommodation portion 16 that accommodates the reduction mechanism 13, and a gear accommodation portion 18 in which the drive spindle insertion hole 14 is formed so as to penetrate the transmission gear 193. Have. Further, the motor housing 31 in the motor gear housing 29 has a bottomed cylindrical motor accommodating portion 32 that accommodates the electric motor 17 and a body wall side piston 187 that is accommodated by a drive spindle insertion hole 229 penetratingly formed therein. And a main body wall side piston accommodating portion 36. The gear housing 15 constituting the motor gear housing 29 and the motor housing 31 are integrally fixed by fastening bolts (not shown).

The inner pad side piston 183 accommodated in the cylinder body 169 and the main body wall side piston 187 accommodated in the main body wall side piston accommodating part 36 are expanded by a thrust generating mechanism 139 provided therebetween. .

The thrust generating mechanism 139 accommodated in the cylinder body 169 is in the radial direction of the thrust generating mechanism 139 with respect to the pair of

arm portions

149 and 149 provided on both the return side and the return side of the rotor 141 in the support 147. It is fixed via a pair of mounting

portions

171 and 171 of the cylinder body 169 arranged on the outside. The cylinder body 169 in which the thrust generating mechanism 139 is accommodated, and the motor gear housing 29 in which the electric motor 17 and the speed reduction mechanism 13 are accommodated are integrally fixed to the support 147.

The power from the electric motor 17 is input to the final output gear 19 through the speed reduction mechanism 13 arranged on the same axis. The power input to the final output gear 19 is thrust that is offset with respect to the electric motor 17 via the output gear 21A that meshes with the final output gear 19 and is disposed between the electric motor 17 and the speed reduction mechanism 13. It is output to the drive spindle 195 of the generation mechanism 139.

The thrust generation mechanism 139 is configured by a combination of a feed screw mechanism 189 and a ball ramp mechanism 191 that is a high-efficiency axial force conversion mechanism.
The feed screw mechanism 189 is a drive spindle 195 as a rotation input member driven via a transmission gear 193 rotated by the output gear 21A, and a drive screwed with a male screw portion 197 provided on the outer half of the drive spindle 195. A side rotor 199 and a thrust bearing 201 interposed between the inner side end of the drive spindle 195 and the main body wall 155. A transmission gear 193 is provided on the outer periphery of the drive spindle 195. The transmission gear 193 meshes with an output gear 21 A that is rotatably supported by the gear base 12. The drive spindle 195 is rotated via the transmission gear 193 when the output gear 21A is rotated. Here, the output gear 21 A itself has a smaller diameter than the output gear 21 in the first embodiment. It has a large diameter. The male screw portion 197 of the drive spindle 195 is screwed into a screw hole 203 provided in the central portion of the drive-side rotor 199 constituting the ball ramp mechanism 191.

The drive spindle 195 has a transmission mechanism that can move relative to the output gear 21A in the axial direction and can transmit rotational force. The transmission mechanism capable of relative movement and transmission of rotational force includes a pair of key portions (not shown) at both ends in the diameter direction formed on the drive spindle 195 and a bush 196 fitted in the transmission gear 193 so as not to be relatively rotatable. Are formed by a slide mechanism circle formed by a pair of key grooves (not shown) at both ends in the diameter direction. That is, the drive spindle 195, the transmission gear 193, the key portion, the key groove, and the output gear 21 A constitute a transmission gear device 205 having the slide mechanism 20.
The transmission mechanism of the drive spindle 195 that can move in the axial direction relative to the output gear 21A and can transmit the rotational force is not limited to the slide mechanism 20, but is a transmission gear fixed to the drive spindle 195. On the other hand, the tooth width of the output gear can be sufficiently widened.

The ball ramp mechanism 191 includes the driving side rotor 199, the driven side rotor 209, and a plurality of rolling elements 211 interposed between the driving side rotor 199 and the driven side rotor 209. The drive-side rotor 199 and the driven-side rotor 209 have a plurality of circumferential positions on the mutually facing surfaces, each having a plurality of places (for example, 3 to 4 places), each having an arc shape when viewed in the axial direction. A driving side lamp unit 213 and a driven side lamp unit 215 are provided.

The depths in the axial direction of the driving side lamp part 213 and the driven side lamp part 215 change gradually with respect to the circumferential direction, but the direction of change varies between the driving side lamp part 213 and the driven side lamp part 215. The directions are opposite to each other. Accordingly, when the driving-side rotor 199 and the driven-side rotor 209 are relatively rotated and each rolling element 211 rolls along the driving-side ramp portion 213 and the driven-side ramp portion 215, the driving-side rotor 199 and the driven-side rotor The interval of 209 can be expanded with great force.
Such a ball ramp mechanism 191 is disposed so as to be loosely fitted on the inner diameter side of the inner pad side piston 183.

Further, a biasing spring is provided between the inner side surface of the tip end portion (left end portion in FIG. 13) of the drive side rotor 199 and the retaining ring 217 fixed to the inner side of the inner peripheral surface of the inner pad side piston 183. 219 is provided via a seat spring 221. The biasing spring 219 gives the driving-side rotor 199 an elastic force in a direction opposite to the rotation direction when the driving-side rotor 199 is operated (when a braking force is generated) and an elastic force toward the outer side. ing.

Also, the outer peripheral surface of the front end portion of the driven rotor 209 becomes a rotor-side inclined surface 223 that is inclined in a direction in which the outer diameter decreases toward the outer side. The rotor-side inclined surface 223 is provided on the inner surface of the inner end of the inner pad-side piston 183 and faces the partially conical concave receiving surface 225 that is inclined in the same direction at the same angle. The driven rotor 209 is prevented from rotating by the wedge effect based on the contact between the rotor-side inclined surface 223 and the receiving surface 225.

The thrust generating mechanism 139 presses the inner pad side piston 183 and the inner pad 143 through the driven side rotor 209 by the extension of the ball ramp mechanism 191. The reaction force from the inner pad 143 that presses the rotor 141 is supported by the thrust bearing 201 with which the inner side end 207 of the drive spindle 195 abuts.

A drive spindle insertion hole 229 opens in the piston housing part 36 on the body wall side of the motor housing 31. The drive spindle 195 is inserted through the drive spindle insertion hole 229 on the inner side end 207 side and passes through the transmission gear 193 of the gear housing 15. The inner side end 207 side of the drive spindle 195 that has passed through the transmission gear 193 is inserted into the drive spindle insertion hole 229 of the main body wall side piston housing part 36. The inner end 207 of the drive spindle 195 inserted through the drive spindle insertion hole 229 is brought into contact with the thrust bearing 201 in the main body wall side piston 187 accommodated in the main body wall side piston accommodating part 36.

The body wall side piston 187 is housed in the body wall side piston housing part 36 so as to freely advance and retract. The outer periphery of the main body wall portion side piston 187 protruding from the main body wall portion side 155 side of the main body wall portion side piston accommodating portion 36 is covered and protected by the main body wall portion side piston boot 233.

The thrust bearing 201 is supported movably in the axial direction of the rotor 141 inside the bottomed cylindrical main body wall side piston 187. The thrust bearing 201 supports the inner end 207 of the drive spindle 195 and receives a reaction force from the inner pad 143 received by the drive spindle 195. An axial force sensor 235 is provided between the thrust bearing 201 and the inner bottom surface 237 of the main body wall side piston 187. The body wall side piston 187 is projected to the body wall part 155 side by receiving the reaction force from the drive spindle 195 at the inner bottom surface 237 via the axial force sensor 235. The outer bottom surface 239 of the body wall side piston 187 abuts on a piston abutting recess 241 formed in the body wall 155 of the caliper 153.

The speed reduction mechanism 13 has a gear housing 15 that defines a gear housing space. The reduction gear housing 16 of the gear housing 15 includes an input gear shaft 59, a first sun gear 61 that rotates integrally with the input gear shaft 59, a first planetary gear 63 that meshes with the first sun gear 61, and a first A first planet carrier 65 that holds the planetary gear 63 around the first sun gear 61 so as to freely rotate and revolve, and a first inner tooth 67 that is formed on the inner peripheral surface of the gear housing 15 and meshes with the first planetary gear 63. A second sun gear 69 disposed on the electric motor 17 side with respect to the first sun gear 61 and rotating integrally with the first planet carrier 65, a second planet gear 71 meshing with the second sun gear 69, A second planetary carrier 73 that holds the second planetary gear 71 around the second sun gear 69 so as to rotate and revolve, and a second inner tooth that is formed on the inner peripheral surface of the gear housing 15 and meshes with the second planetary gear 71. 75 and the second sun gear 69 The final output gear 19 that is disposed on the electric motor 17 side and is rotationally driven by the second planetary carrier 73 and meshes with the final output gear 19 and is rotatable about a rotation axis parallel to the input gear shaft 59. An output gear 21A is provided.

The speed reduction mechanism 13 decelerates high-speed rotation from the output shaft 77 of the electric motor 17 with a large reduction ratio by a two-stage planetary gear mechanism connected in series, and transmits it to the final output gear 19. The rotation of the final output gear 19 is transmitted to the output gear 21A, and finally input from the output gear 21A to the transmission gear 193 of the thrust generating mechanism 139.

Next, the operation of the floating electric disc brake 135 will be described.
The floating electric disc brake 135 rotates the output shaft 77 of the electric motor 17 by energizing the electric motor 17 when the electric brake is operated. The rotational movement of the output shaft 77 is transmitted to the speed reduction mechanism 13. The rotation reduced by the reduction mechanism 13 rotates the output gear 21 A via the final output gear 19. The rotation of the output gear 21 A is transmitted to the transmission gear 193, and then transmitted to the drive spindle 195 of the feed screw mechanism 189 constituting the ball ramp mechanism 191, thereby driving the drive spindle 195 to rotate.

In the initial stage of this rotational drive, the drive-side rotor 199 does not rotate due to the frictional resistance between the rotor-side inclined surface 223 and the receiving surface 225 and the resistance of the biasing spring 219 and the like. Then, the drive-side rotor 199 moves in parallel to the tip side of the drive spindle 195 together with the driven-side rotor 209 based on the threaded engagement between the male threaded portion 197 of the drive spindle 195 and the screw hole 203 of the drive-side rotor 199 ( Move toward the rotor 141 without rotating). By this parallel movement, the inner pad side piston 183 is pushed out to the outer side, and the gap between the axial side surface of the rotor 141 and the inner pad 143 is closed. The reaction force from the inner pad 143 pressed against the rotor 141 is transmitted to the thrust bearing 201 via the drive spindle 195. The reaction force transmitted to the thrust bearing 201 is pushed out to the main body wall side piston 187 inner side via the axial force sensor 235. The caliper 153 in which the main body wall portion 155 is pushed out to the inner side by the main body wall portion side piston 187 is moved in a direction in which the claw portion 157 approaches the rotor 141, so that the outer pad 145 is pressed against the axial side surface of the rotor 141. . During such parallel movement, each rolling element 211 is located at the deepest end of the driving side ramp 213 and the driven side ramp 215.

As a result of the parallel movement, gaps between the respective parts are lost, and when the resistance to the movement of the drive-side rotor 199 and the driven-side rotor 209 further toward the rotor 141 is increased, the drive-side rotor 199 is driven by the drive spindle. The drive side rotor 199 and the driven side rotor 209 rotate relative to each other. Then, each rolling element 211 moves to the shallower side of the driving side ramp portion 213 and the driven side ramp portion 215 while rolling, and the interval between the driven side rotor 209 and the driving side rotor 199 increases. Since the inclination angles of the driven-side lamp portion 215 and the driving-side lamp portion 213 are gentle, the force for increasing the distance between the driven-side rotor 209 and the driving-side rotor 199 increases.

The force that increases the distance between the driven-side rotor 209 and the driving-side rotor 199 further pushes the inner pad-side piston 183 toward the outer side. The pushed inner pad side piston 183 presses the inner pad 143 against the rotor 141. The reaction force from the inner pad 143 further pushes the main body wall side piston 187 to the inner side through the driving spindle 195, together with the force to increase the distance between the driven side rotor 209 and the driving side rotor 199.

As a result, the thrust generating mechanism 139 can perform braking by pressing the inner pad 143 and the outer pad 145 against both side surfaces of the rotor 141 with a large force. The magnitude of the force for pressing the inner pad 143 and the outer pad 145 against both side surfaces of the rotor 141 can be adjusted by feedback control based on the measurement signal of the axial force sensor 235. It can also be performed by feedforward control that adjusts the amount of current supplied to the electric motor 17.

When the operation of the floating electric disc brake 135 is released, the electric motor 17 is energized so that the output shaft 77 of the electric motor 17 is moved in a direction opposite to that during operation (when braking force is generated). Rotate only a fixed amount (a sufficient amount of rotation to release the braking force). The rotational movement of the output shaft 77 is transmitted to the input gear shaft 59 of the speed reduction mechanism 13 through the same path as that during operation. Further, after the rotational movement of the input gear shaft 59 is transmitted to the output gear 21A via the final output gear 19 of the speed reduction mechanism 13, the drive spindle 195 of the feed screw mechanism 189 constituting the thrust generating mechanism 139 is rotationally driven. To do. Then, the distance between the driven-side rotor 209 and the driving-side rotor 199 is narrowed, and the driving-side rotor 199 moves in parallel with the driven-side rotor 209 toward the inner side end 207 side of the driving spindle 195. By this parallel movement, the inner pad side piston 183 is returned to the inner side, and the gap between the axial side surface of the rotor 141 and the inner pad 143 is widened. The caliper 153 from which the pressing force of the thrust generating mechanism 139 has been released becomes movable in the axial direction along with the drive spindle 195, so that the outer pad 145 can also be separated from the axial side surface of the rotor 141.

Next, the operation of the floating electric disc brake 135 to which the electric brake driving device 137 according to the second embodiment described above is applied will be described.
In the above-described floating electric disc brake 135, the thrust generating mechanism 139 is accommodated in the cylinder body 169. The electric motor 17 and the speed reduction mechanism 13 are accommodated in the motor gear housing 29. The cylinder body 169 and the motor gear housing 29 are integrally fixed to the support 147. Thereby, the weight load of the caliper 153 is reduced.
Furthermore, the motor gear housing 29 is provided with the electric motor 17 and the speed reduction mechanism 13 coaxially. The coaxial is arranged in parallel with the axis of the cylinder body 169 in the same direction (offset arrangement). In the motor gear housing 29, an output gear 21A is disposed at a substantially central position in the axial direction between the electric motor 17 and the speed reduction mechanism 13 arranged on the same axis. The power of the electric motor 17 is input to the output gear 21 A by the final output gear 19 of the speed reduction mechanism 13 through the speed reduction mechanism 13. That is, power from the electric motor 17 is decelerated and input to the thrust generating mechanism 139 via the output gear 21A.

Therefore, in the floating electric disc brake 135, the cylinder body 169 and the motor gear housing 29 are offset, so that the axial length can be shortened as compared with a structure in which these are coaxially arranged. Further, the power from the electric motor 17 can be output to the thrust generating mechanism 139 from the substantially central position in the axial direction of the motor gear housing 29 by the output gear 21A. Thereby, the cylinder body 169 and the motor gear housing 29 can be integrated compactly. As a result, in the floating type electric disc brake 135, the weight balance with respect to the caliper sliding portion is improved, layout performance is improved and vibration is hardly generated. Further, the holding and sliding performance of the caliper 153 is improved.

Therefore, the electric

brake driving devices

11 and 137 according to the above-described embodiments improve the ease of assembly to the small

electric drum brakes

79 and 131, and deteriorate the weight balance with respect to the caliper sliding portion of the floating electric disc brake 135. An effect called suppression can be produced, layout properties are good, and application to a small brake can be made possible.

Here, the features of the embodiment of the electric brake driving device according to the present invention described above will be briefly summarized below.
[1] Power from the electric motor (17) is input to the final output gear (19) through the reduction mechanism (13) arranged on the same axis, and the output gear (21) meshes with the final output gear (19). ) Through which the electric brake (11) is output to the thrust generation mechanism (23) that is offset with respect to the electric motor (17).
The drive device (11) for an electric brake, wherein the output gear (21) is disposed between the electric motor (17) and the speed reduction mechanism (13).
[2] A pair of brake shoes (the first brake shoe 85 and the first brake shoe 85) are disposed so as to face the inner peripheral surface of the brake drum and are movably supported by the backing plate (81). Two brake shoes 87), which is interposed between one adjacent ends of the pair of brake shoes (first brake shoe 85 and second brake shoe 87) and expands each of the pair of brake shoes (1). Drive device (11).
[3] The thrust generation mechanism (139) is disposed on the inner side of the inner pad (143) in the inner pad (143) and the outer pad (145) disposed in a state of facing the axial side surface of the rotor (141). The electric brake drive device (137) according to [1], wherein the inner pad (143) and the outer pad (145) are pressed against the side surface in the axial direction of the rotor (141).
[4] The thrust generation mechanism (23) is a nut member (35) that can rotate integrally with the output gear (21) and can move relative to the axial direction, and the nut member (35). Is constituted by a screw mechanism by a combination with a protruding screw (39) arranged coaxially to
The protruding screw (39) includes a first protruding member (45) having a first protruding end (41) at one end and a male screw (43) at the other end, and a second protruding end (47) at one end. And a second projecting member (51) having a fitting shaft portion (49) at the other end,
The male screw portion (43) of the first projecting member (45) is screwed into the female screw portion (53) at one end of the nut member (35), and a fitting hole (55 at the other end of the nut member (35)). The electric brake driving device (11) according to [1] or [2], wherein the fitting shaft portion (49) of the second projecting member (51) is rotatably fitted to the second projecting member (51).
[5] The thrust generation mechanism (139) includes a combination of a feed screw mechanism (189) and a high-efficiency axial force conversion mechanism (ball ramp mechanism 191).
The feed screw mechanism (189) includes a drive spindle (195) as a rotation input member driven via a transmission gear (193) rotated by the output gear (21A), and an outer of the drive spindle (195). A drive-side rotor (199) screwed into a male thread portion (197) provided on the side half, an inner-side end (207) of the drive spindle (195), and an inner-side end (main body wall portion 155) of the caliper (153) A thrust bearing (201) interposed between
The high-efficiency axial force conversion mechanism (ball ramp mechanism 191) is provided between the drive-side rotor (199), the driven-side rotor (209), and the drive-side rotor (199) and the driven-side rotor (209). A rolling element (211) interposed between
The drive device for an electric brake according to [1] or [3], wherein the drive spindle (195) can move relative to the output gear (21A) in the axial direction and can transmit rotational force. (137).
[6] The electric brake driving device (11, 137) according to any one of [1] to [5], wherein the speed reduction mechanism (13) includes at least one planetary gear mechanism.
[7] The deceleration mechanism (13)
A gear housing (15) defining a gear housing space;
An input gear shaft (59) driven to rotate by the electric motor (17);
A first planetary gear (63) meshing with a first sun gear (61) rotating integrally with the input gear shaft (59);
A first planet carrier (65) holding the first planet gear (63) around the first sun gear (61) so as to freely rotate and revolve;
First internal teeth (67) formed on the inner peripheral surface of the gear housing (15) and meshing with the first planetary gear (63);
A second sun gear (69) disposed on the electric motor (17) side relative to the first sun gear (61) and rotating integrally with the first planet carrier (65);
A second planetary gear (71) meshing with the second sun gear (69);
A second planet carrier (73) for holding the second planetary gear (71) around the second sun gear (69) so as to freely rotate and revolve;
Second internal teeth (75) formed on the inner peripheral surface of the gear housing (15) and meshing with the second planetary gear (71);
A final output gear (19) disposed on the electric motor (17) side with respect to the second sun gear (69) and driven to rotate by the second planet carrier (73);
The electric brake driving device according to [6], further comprising: an output gear (21A) meshing with the final output gear (19) and rotatable about a rotation axis parallel to the input gear shaft (59). 137).

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.
This application is based on a Japanese patent application filed on July 9, 2015 (Japanese Patent Application No. 2015-138062), the contents of which are incorporated herein by reference.

According to the electric brake driving device of the present invention, the electric brake driving device which has good layout and can be applied to a small brake can be suitably used for an electric drum brake and an electric disc brake.

DESCRIPTION OF SYMBOLS 11 ... Electric brake drive device 13 ... Reduction mechanism 15 ... Gear housing 17 ... Electric motor 19 ... Final output gears 21, 21A ... Output gear 23 ... Thrust generating mechanism 35 ... Nut member 39 ... Projecting screw 41 ... First projecting end 43 ... male screw portion 45 ... first projecting member 47 ... second projecting end portion 49 ... fitting shaft portion 51 ... second projecting member 53 ... female screw portion 55 ... fitting hole 59 ... input gear shaft 61 ... first sun gear 63 ... first planetary gear 65 ... first planetary carrier 67 ... first inner tooth 69 ... second sun gear 71 ... second planetary gear 73 ... second planetary carrier 75 ... second inner tooth 81 ... backing plate 85 ... first brake Shoe (brake shoe)
87 ... Second brake shoe (brake shoe)
137: Electric brake driving device 141 ... Rotor 143 ... Inner pad 145 ... Outer pad 153 ... Caliper 155 ... Body wall (inner side end of caliper)
189 ... Feed screw mechanism 191 ... Ball ramp mechanism (high efficiency axial force conversion mechanism)
193 ... Transmission gear 195 ... Drive spindle (rotary input member)
199... Drive side rotor 201... Thrust bearing 209... Driven side rotor 211.

Claims

Thrust generating mechanism in which power from the electric motor is input to the final output gear via a reduction mechanism arranged on the same axis, and offset with respect to the electric motor via an output gear meshing with the final output gear A drive device for an electric brake that is output to
An electric brake driving device in which the output gear is disposed between the electric motor and the speed reduction mechanism.
The thrust generating mechanism is disposed so as to face the inner peripheral surface of the brake drum and is interposed between adjacent ends of a pair of brake shoes that are movably supported by a backing plate. The drive device for an electric brake according to claim 1, wherein each of them is expanded.
The thrust generation mechanism is disposed on the inner side of the inner pad and the outer pad disposed in a state of facing the axial side surface of the rotor, and the inner pad and the outer pad are respectively pressed against the axial side surface of the rotor. The electric brake drive device according to claim 1 attached.
The thrust generating mechanism is a screw mechanism that is a combination of a nut member that is integrally rotatable with respect to the output gear and that is relatively movable in the axial direction, and a protruding screw that is coaxially disposed on the nut member. Configured,
The projecting screw has a first projecting member having a first projecting end at one end and a male threaded portion at the other end, and a second projecting having a second projecting end at one end and a fitting shaft at the other end. A member, and
The male screw portion of the first projecting member is screwed into the female screw portion at one end of the nut member, and the fitting shaft portion of the second projecting member is rotatably fitted in the fitting hole at the other end of the nut member. The driving device for an electric brake according to claim 1 or 2.
The thrust generation mechanism is configured by a combination of a feed screw mechanism and a high-efficiency axial force conversion mechanism,
A drive spindle as a rotation input member driven by the feed screw mechanism via a transmission gear rotated by the output gear; a drive-side rotor screwed into a male screw portion provided in an outer half of the drive spindle; A thrust bearing interposed between an inner side end of the drive spindle and an inner side end of the caliper,
The high-efficiency axial force conversion mechanism includes the driving-side rotor, a driven-side rotor, and a rolling element interposed between the driving-side rotor and the driven-side rotor,
The electric brake drive device according to claim 1 or 3, wherein the drive spindle is relatively movable in the axial direction with respect to the output gear, and is capable of transmitting a rotational force.
The electric brake drive device according to any one of claims 1 to 5, wherein the speed reduction mechanism includes at least one planetary gear mechanism.
The deceleration mechanism is
A gear housing that defines a gear housing space;
An input gear shaft that is rotationally driven by the electric motor;
A first planetary gear meshing with a first sun gear that rotates integrally with the input gear shaft;
A first planet carrier that holds the first planetary gear around the first sun gear so as to freely rotate and revolve;
First internal teeth formed on the inner peripheral surface of the gear housing and meshing with the first planetary gear;
A second sun gear disposed on the electric motor side with respect to the first sun gear and rotating integrally with the first planet carrier;
A second planetary gear meshing with the second sun gear;
A second planet carrier for holding the second planetary gear so as to freely rotate and revolve around the second sun gear;
Second internal teeth formed on the inner peripheral surface of the gear housing and meshing with the second planetary gear;
A final output gear that is disposed on the electric motor side with respect to the second sun gear and is rotationally driven by the second planet carrier;
The drive device for an electric brake according to claim 6, further comprising: an output gear that meshes with the final output gear and is rotatable about a rotation axis parallel to the input gear shaft.