Electric brake device

Abstract

Provided is an electric brake device which has excellent assemblability so that an electric actuator can be coupled to a bracket member by applying a single operation to the electric actuator. The electric actuator is inserted into the bracket member in the axial direction of a motor part of the electric actuator, thereby being coupled to the bracket member.

Description

[Technical Field]

[0001] The present invention relates primarily to an electric braking device for automobiles, and in particular to an improvement in an electric braking device that includes a bracket member fixed to a support member of a brake mechanism and an electric actuator that is connected to this bracket member and can operate the brake mechanism. [Background technology]

[0002] In this type of electric brake device, an electric actuator is known to be connected by a bayonet structure to a bracket member fixed to a back plate, which is a support member for the drum brake mechanism (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US2020 / 0378460A1 Summary of the Invention [Problem to be solved by the invention]

[0004] However, to connect the electric actuator to the bracket member using a bayonet structure, the electric actuator is advanced relative to the bracket member in the axial direction of its output spindle, and then rotated around the output spindle to engage the engaging portions provided on both members, completing the connection work. As such, the connection work requires the electric actuator to be operated in two directions, linearly and rotationally, which cannot be said to be easy to assemble.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide an electric brake device that is easy to assemble, in which an electric actuator can be connected to a bracket member with a single operation. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention relates to an electric brake device, and a first feature of the electric brake device is that it comprises a bracket member fixed to a support member of a brake mechanism, and an electric actuator coupled to the bracket member and capable of operating the brake mechanism, the electric actuator having a motor unit, and the electric actuator is engaged with the bracket member by inserting the electric actuator into the bracket member along the axial direction of the motor unit. The motor unit corresponds to a motor case unit 12a in an embodiment of the present invention described below.

[0007] In addition to the first feature, the present invention has a second feature in that the bracket member is provided with a holding means for holding the motor section.

[0008] Furthermore, in addition to the second feature, the holding means is , the insertion direction of the electric actuator The third feature is that it is placed on the tip side.

[0009] Furthermore, in addition to the second or third feature, the present invention has a fourth feature in that the holding means has a rail structure.

[0010] Furthermore, in addition to any one of the first to fourth features, the present invention provides a method for connecting a bracket member and an electric actuator to each other, the method comprising: providing an elastic engagement means between the bracket member and the electric actuator; and providing an elastic engagement means having a convex engagement portion integrally connected to one of the bracket member and the electric actuator; and a concave engagement portion integrally connected to the other of the bracket member and the electric actuator. Convex and concave The elastic deformation of one of the engaging parts Convex and concave A fifth feature is that the engaging portions engage with each other.

[0011] Furthermore, in addition to any of the first to fifth features, the present invention has a sixth feature in that the electric actuator includes an output spindle portion having an axis parallel to that of the motor portion, and the output spindle portion is engaged with a retaining cylinder provided on the bracket member by fitting the output spindle portion into the retaining cylinder. The output spindle portion corresponds to output case portion 12b in an embodiment of the present invention described below.

[0012] Furthermore, in addition to any one of the sixth features, the present invention has a seventh feature in that the retaining cylinder is provided with a press-fit portion into which the output spindle portion is press-fitted.

[0013] Furthermore, in addition to any of the first to seventh features, the present invention has an eighth feature in that the bracket member is made of synthetic resin and a housing tube that houses the motor portion is integrally molded with the bracket member. [Effects of the Invention]

[0014] According to the first feature of the present invention, the electric actuator can be connected to the bracket member by a single operation of inserting the electric actuator into the bracket member in the axial direction of the motor part of the electric actuator, thereby making it easy to assemble.

[0015] According to the second feature of the present invention, the motor section is held by the holding means on the bracket member, so that when the vehicle vibrates, the rotation of the electric actuator can be restricted and the oscillation of the motor section can be suppressed.

[0016] According to the third feature of the present invention, by arranging the holding means at the tip side of the motor part, away from the base part, it is possible to more effectively suppress the swinging of the motor case part.

[0017] According to a fourth feature of the present invention, by making the holding means a rail structure, it is possible to restrict the movement of the motor unit in the rotational direction and suppress vibrations received from the vehicle body.

[0018] According to the fifth feature of the present invention, the elastic engagement means can have a simple structure.

[0019] According to the sixth feature of the present invention, it is possible to achieve both the holding of the output spindle portion by the holding cylinder and the connection of the output spindle portion and the holding cylinder.

[0020] According to the seventh feature of the present invention, the holding cylinder is provided with a press-fit portion into which the output spindle portion is press-fitted, thereby making it possible to strengthen the bonding strength between the output spindle portion and the holding cylinder.

[0021] According to the eighth feature of the present invention, the bracket member is made of synthetic resin, thereby making it lightweight, and the bracket member can be reinforced by a housing tube for housing the motor section that is integrally molded into the bracket member, and the bracket member made of synthetic resin can reliably support the electric actuator. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a rear view of the drum brake device according to the present invention. [Figure 2] Side view of Figure 1. [Figure 3] FIG. [Figure 4] Side view of Figure 3. [Figure 5] 5 is a view taken along the line 5-5 in FIG. 4 (a plan view of the bracket member). [Figure 6] Cross-sectional view taken along line 6-6 in Figure 5. [Figure 7] FIG. [Figure 8] An enlarged view of the area indicated by arrow 8 in Figure 4. DETAILED DESCRIPTION OF THE INVENTION

[0023] An embodiment of the present invention will be described with reference to the accompanying drawings 1 to 8. FIG.

[0024] 1 to 3, reference numeral 2 denotes an electric parking drum brake device as an electric brake device of the present invention, which is equipped on the rear wheels of an automobile. A back plate 3 as a support member for this electric parking drum brake device 2 is supported by a suspension member (not shown), and has a center hole 4 in its center, through which the rear axle passes. A known main brake mechanism and parking brake mechanism, including brake shoes etc., are arranged on the front side of this back plate 3.

[0025] A boss 5 is formed as a protrusion on one side of the back surface of the back plate 3. This boss 5 has a support surface 5a that slopes down from the ridgeline toward the outer periphery of the back plate 3 and a through hole 5b that opens into it. A bracket member 7 is fixed to the back plate 3 so as to cover the support surface 5a, and an electric actuator 8 is attached to this bracket member 7.

[0026] The actuator mechanism 9 of the electric actuator 8 comprises a motor 10, an output spindle 11 arranged adjacent to the motor 10 with its axes Y1, Y2 parallel to each other, and a transmission mechanism (not shown) that converts the rotational output of the motor 10 into thrust and transmits it to the output spindle 11. The actuator case 12 that houses the actuator mechanism 9 comprises a cylindrical motor case portion 12a (corresponding to the motor portion of the present invention) that houses the motor 10, a cylindrical output case portion 12b (corresponding to the output spindle portion of the present invention) that is arranged adjacent to the motor case portion 12a and houses the output spindle 11, and a transmission case portion 12c that houses the transmission mechanism and integrally connects the base of the motor case portion 12a (the rotational output side of the motor 10) to the output case portion 12b. The motor case portion 12a shares the axis Y1 with the motor 10, and the output case portion 12b shares the axis Y2 with the output spindle 11. A power supply connector 17 for the motor 10 is provided at the base of the motor case portion 12a.

[0027] The output case portion 12b is formed with a smaller diameter than the motor case portion 12a. The output case portion 12b has a large-diameter cylindrical portion 13 that protrudes from the front surface of the transmission case portion 12c, and a small-diameter cylindrical portion 14 that is coaxially connected to the large-diameter cylindrical portion 13 via a step portion 15 and has a smaller diameter than the large-diameter cylindrical portion 13. The protruding length of the output case portion 12b from the front surface of the transmission case portion 12c is shorter than the protruding length of the motor case portion 12a from the front surface of the transmission case portion 12c.

[0028] A bellows-type dustproof boot 16 is stretched between the tip of the small-diameter cylindrical portion 14 and the tip of the output spindle 11 protruding from the tip of the small-diameter cylindrical portion 14.

[0029] 1 and 3 to 7, the bracket member 7 is molded entirely from synthetic resin and has a bracket base 7a on the outer periphery of which are arranged a plurality of fixing pieces 18 that are fixed to the back plate 3 by fixing members 19 such as bolts. A cylindrical first housing tube 21 and a cylindrical second housing tube 22 that is smaller in diameter than the first housing tube 21 are integrally molded adjacent to and parallel with the bracket base 7a, and the second housing tube 22 is supported on the support surface 5a of the boss 5.

[0030] A cylindrical retaining tube 24 that is thinner than the second housing tube 22 is integrally and coaxially connected to the upper end of the second housing tube 22. A plurality of axially extending ribs 25a (see FIGS. 5 to 7) are formed on the inner peripheral surface of the retaining tube 24 so as to be aligned at equal intervals around the circumference of the retaining tube 24. These ribs 25a form a press-fit portion 25 into which the output case portion 12b is press-fit. A plurality of reinforcing ribs 26 that stand up from the upper surface of the bracket base 7a are also formed integrally on the outer peripheral surface of the retaining tube 24.

[0031] Thus, the tip end of the motor case portion 12a is inserted into the first housing cylinder 21. Furthermore, the small diameter cylindrical portion 14 of the output case portion 12b is press-fitted into the inner peripheral surface of the retaining cylinder 24 at the plurality of ribs 25a, i.e., the press-fit portion 25. The press-fit limit is regulated by the step portion 15 between the large diameter cylindrical portion 13 and the small diameter cylindrical portion 14 abutting against the end face of the retaining cylinder 24.

[0032] Here, the multiple ribs 25a on the inner surface of the retaining tube 24 that form the press-fit portion 25 are relatively susceptible to elastic deformation, making it easier to set the press-fit interference of the small diameter cylindrical portion 14 and effective in avoiding cracks in the retaining tube 24 due to the press-fit.

[0033] When the small diameter cylindrical portion 14 is press-fitted into the retaining cylinder 24, the tip of the output spindle 11 passes through the second housing cylinder 22 and the through-hole 5b of the boss 5, protruding from the front side of the back plate 3, and a brake cable (not shown) connected to the parking mechanism is connected to it. The output spindle 11 is driven to move forward and backward in the axial direction by the forward and reverse rotation of the rotor of the motor 10, and activates and releases the parking mechanism via the brake cable.

[0034] Between the small diameter cylindrical portion 14 of the output case portion 12b and the retaining cylinder 24 having the press-fit portion 25 into which the small diameter cylindrical portion 14 is press-fitted, there is provided an elastic engagement means 28 that locks the press-fit state of the small diameter cylindrical portion 14 and the press-fit portion 25. The elastic engagement means 28 is composed of a plurality of (two in the illustrated example) convex engagement portions 29 (see FIG. 8) formed on the outer periphery of the small diameter cylindrical portion 14 so as to be aligned at equal intervals along the circumferential direction thereof, and a plurality of concave engagement portions 30 (see FIG. 6) formed on the retaining cylinder 24 that elastically engage with the convex engagement portions 29 when the small diameter cylindrical portion 14 and the press-fit portion 25 are press-fitted.

[0035] Specifically, each convex engagement portion 29 consists of a square guide protrusion 31 that protrudes from the outer peripheral surface of the small diameter cylindrical portion 14 and an engagement claw 32 that protrudes from the front of this guide protrusion 31, and this engagement claw 32 has a slope 32b that descends from the top 32a toward the tip side of the small diameter cylindrical portion 14, and a vertical surface 32c that extends from the top 32a toward the guide protrusion 31.

[0036] On the other hand, each recessed engaging portion 30 is made up of a guide wall 33 with a U-shaped cross section formed so as to expand a part of the peripheral wall of the retaining tube 24 in the radial direction, and an engaging hole 34 provided in this guide wall 33, and since the retaining tube 24 is made of synthetic resin, the guide wall 33 can be elastically deformed in the radial direction of the retaining tube 24. In particular, in the illustrated example, the thickness of the guide wall 33 is set smaller than that of the retaining tube 24 to facilitate this elastic deformation.

[0037] Thus, when the small diameter cylindrical portion 14 is press-fitted into the press-fit portion 25 of the retaining tube 24, first the guide protrusions 31 enter the inner grooves of the guide wall 33, the inclined surfaces 32b of the engaging claws 32 elastically deform the guide wall 33 radially outward, and when the small diameter cylindrical portion 14 reaches its limit of press-fitting into the press-fit portion 25 of the retaining tube 24, the engaging claws 32 reach an engagement position with the engaging holes 34, and the guide wall 33 returns to its original elastic deformation, so that the vertical surfaces 32c of the engaging claws 32 face the inner surfaces of the engaging holes 34. This state is the elastic engagement state of the elastic engaging means 28, and this locks the press-fit state between the small diameter cylindrical portion 14 and the press-fit portion 25 of the retaining tube 24.

[0038] Furthermore, a pair of left and right concave movable rails 37 are formed on the outer surface of the motor case portion 12a, parallel to its axis Y1, and a pair of left and right convex fixed rails 38 with which the movable rails 37 can slidably engage are formed on the outer surface of the retaining tube 24. The sliding engagement of these movable and fixed rails 37, 38 determines the fitting position of the output case portion 12b into the retaining tube 24, the accommodation position of the motor case portion 12a in the first accommodation tube 21, and the engageable position of the elastic engagement means 28, and also prevents rotation of the motor case portion 12a around the retaining tube 24.

[0039] In the illustrated example, the fixed rail 38 has a break in the middle, but the length of the break is shorter than the length of the movable rail 37, so the movable rail 37 will not come off the fixed rail 38. Of course, the fixed rail 38 may be formed as a continuous piece without breaks over its entire length. These movable and fixed rails 37, 38 constitute a holding means 36 that holds the motor case part 12a.

[0040] Next, the operation of this embodiment will be described.

[0041] When attaching the electric actuator 8 to the bracket member 7, first, the movable rail 37 of the motor case portion 12a is slidably engaged with the fixed rail 38 of the bracket member 7, and the actuator case 12 is pressed toward the bracket member 7. Due to the positioning and guiding action of both rails 37, 38, the tip of the motor case portion 12a is inserted into the first housing cylinder 21 of the bracket member 7, and at the same time, the small diameter cylindrical portion 14 of the output case portion 12b is inserted into the holding cylinder 21 of the bracket member 7. The small-diameter cylindrical portion 14 is press-fitted into the press-fit portion 25 of the cylinder 24, and the guide protrusions 31 of the small-diameter cylindrical portion 14 engage with the inner grooves of the guide wall 33 of the retaining cylinder 24, and the inclined surfaces 32b of the engaging claws 32 elastically deform the guide wall 33 radially outward, and when the small-diameter cylindrical portion 14 reaches its limit of press-fitting into the press-fit portion 25 of the retaining cylinder 24, the engaging claws 32 reach an engagement position with the engaging holes 34, and the guide wall 33 returns to its original elastic deformation, so that the vertical surfaces 32c of the engaging claws 32 face the inner surfaces of the engaging holes 34, and the elastic engaging means 28 enters an elastically engaged state. This locks the press-fit state between the small-diameter cylindrical portion 14 and the press-fit portion 25 of the retaining cylinder 24, as well as the inserted state of the motor case portion 12a into the first accommodating cylinder 21.

[0042] In this way, the actuator case 12 is moved toward the bracket member 7 in accordance with the guiding action of the fixed rail 38 and movable rail 37 extending in the axial direction of the motor case portion 12a, and the elastic engagement means 28 is brought into an elastic engagement state by a single linear operation, thereby making it possible to easily connect the electric actuator 8 to the bracket member 7, resulting in extremely good assembly ease.

[0043] Furthermore, when the electric actuator 8 is connected to the bracket member 7, at least a portion of the motor case portion 12a is accommodated in the first accommodating tube 21 of the bracket member 7, thereby reducing the exposed portion of the electric actuator 8 outside the bracket member 7 and making it possible to make the electric brake device more compact.

[0044] Furthermore, the movable and fixed rails 37, 38 that make up the holding means 36 can exert a large resistance to the rotational moment around the holding tube 24 of the motor case section 12a when the holding tube 24 and the output case section 12b are connected by the elastic engaging means 28, so that when the vehicle vibrates, the oscillation around the holding tube 24 of the motor case section 12a that houses the motor 10, which is relatively heavy, can be effectively suppressed, ensuring the durability of the actuator case 12 and also reducing the load acting on the elastic engaging means 28, thereby increasing its durability.

[0045] In this case, arranging the movable and fixed rails 37, 38 at least on the tip side of the motor case portion 12a can more effectively suppress the swinging of the motor case portion 12a.

[0046] Furthermore, the movable and fixed rails 37, 38 that slide in engagement also function to precisely determine the fitting position of the output case portion 12b to the retaining tube 24, thereby contributing to better assembly.

[0047] Furthermore, the elastic engagement means 28 is composed of an engagement claw 32 of the output case portion 12b and an engagement hole 34 of the retaining tube 24, and the surrounding portion of the engagement hole 34 is made elastically deformable to enable engagement therebetween, so that the elastic engagement means 28 can have a simple configuration.

[0048] Furthermore, by making the bracket member 7 from synthetic resin, the weight of the bracket member 7 can be reduced, and by integrally molding the first and second housing tubes 21, 22 with it, the bracket member 7 can be effectively reinforced.

[0049] Furthermore, by pressing the output case portion 12b into the press-fit portion 25 of the retaining tube 24, the bonding strength between the output case portion 12b and the retaining tube 24 is increased, reducing the load in the direction of removal of the output case portion 12b borne by the elastic engagement means 28, thereby improving its durability.

[0050] The above describes an embodiment of the present invention, but the present invention is not limited to the above embodiment, and various design changes can be made without departing from the present invention as described in the claims.

[0051] For example, in the elastic engagement means 28, opposite to the above embodiment, the engagement claws 32 can be provided on the retaining cylinder 24 and the engagement holes 34 can be provided on the output case portion 12b. Also, the motor case portion 12a can be press-fitted into the first housing cylinder 21 of the bracket member, and elastic engagement means can be provided therebetween. Also, opposite to the embodiment, the convex rail 37 and the concave rail 38 that make up the holding means 36 can be formed on the bracket member 7 and the first housing cylinder 21, respectively. The present invention can also be applied to electric brake devices equipped with an electric actuator, such as electric parking disc brake devices.

[0052] This application claims priority to Japanese Patent Application No. 2022-056883, filed March 30, 2022. The entire disclosure of Japanese Patent Application No. 2022-056883, filed March 30, 2022, including the specification, claims, drawings, and abstract, is incorporated herein by reference in its entirety. [Explanation of symbols]

[0053] 2. Electric brake device (electric parking drum brake device) 3. Support member (back plate) 7. Bracket member 8. Electric actuator 9. Actuator mechanism 12a Motor section (motor case section) 12b Output spindle (output case) 12c Transmission case section 21. Storage tube (first storage tube) 24...Holding tube 25 Press-fit section 28 Elastic engagement means 29 Convex engagement portion 30 Recessed engagement portion 36...holding means 37··· Movable rail Y1: Axis of the motor (motor case) Y2: Axis of the output spindle (output case)

Claims

1. An electric brake device, the electric brake device comprising: a bracket member (7) fixed to a support member (3) of the brake mechanism; and an electric actuator (8) coupled to the bracket member (7) and capable of operating the brake mechanism, The electric actuator (8) has a motor section (12a), The electric actuator (8) is engaged with the bracket member (7) by inserting the electric actuator (8) into the bracket member (7) along the axial direction of the motor portion (12a), An elastic engagement means (28) is provided between the bracket member (7) and the electric actuator (8), The electric brake device is characterized in that the elastic engagement means (28) comprises a convex engagement portion (29) integrally connected to one of the bracket member (7) and the electric actuator (8), and a concave engagement portion (30) integrally connected to the other of the bracket member (7) and the electric actuator (8), and that the convex and concave engagement portions (29, 30) engage with each other due to elastic deformation of one of the convex and concave engagement portions (29, 30).

2. An electric brake device, the electric brake device comprising: a bracket member (7) fixed to a support member (3) of the brake mechanism; and an electric actuator (8) coupled to the bracket member (7) and capable of operating the brake mechanism, The electric actuator (8) has a motor section (12a), The electric actuator (8) is engaged with the bracket member (7) by inserting the electric actuator (8) into the bracket member (7) along the axial direction of the motor portion (12a), The bracket member (7) is provided with a holding means (36) for holding the motor portion (12a), The electric brake device is characterized in that the holding means (36) is disposed on the leading end side of the motor section (12a) in the insertion direction of the electric actuator (8).

3. An electric brake device, the electric brake device comprising: a bracket member (7) fixed to a support member (3) of the brake mechanism; and an electric actuator (8) coupled to the bracket member (7) and capable of operating the brake mechanism, The electric actuator (8) has a motor section (12a), The electric actuator (8) is engaged with the bracket member (7) by inserting the electric actuator (8) into the bracket member (7) along the axial direction of the motor portion (12a), The bracket member (7) is provided with a holding means (36) for holding the motor portion (12a), An electric brake device characterized in that the holding means (36) has a rail structure.

4. 3. The electric brake device according to claim 2, An elastic engagement means (28) is provided between the bracket member (7) and the electric actuator (8), The electric brake device is characterized in that the elastic engagement means (28) comprises a convex engagement portion (29) provided on one of the bracket member (7) and the electric actuator (8), and a concave engagement portion (30) provided on the other of the bracket member (7) and the electric actuator (8), and that the convex and concave engagement portions (29, 30) engage with each other due to elastic deformation of one of the convex and concave engagement portions (29, 30).

5. An electric brake device, the electric brake device comprising: a bracket member (7) fixed to a support member (3) of the brake mechanism; and an electric actuator (8) coupled to the bracket member (7) and capable of operating the brake mechanism, The electric actuator (8) has a motor section (12a), The electric actuator (8) is engaged with the bracket member (7) by inserting the electric actuator (8) into the bracket member (7) along the axial direction of the motor portion (12a), The electric brake device is characterized in that the bracket member (7) is made of synthetic resin, and a housing cylinder (21) for housing the motor portion (12a) is integrally formed with the bracket member (7).

6. In the electric brake device according to any one of claims 1 to 3 and 5, an electric brake device, characterized in that the electric actuator (8) includes an output spindle portion (12b) whose axis is parallel to that of the motor portion (12a), and the output spindle portion (12b) is engaged with a retaining cylinder (24) provided on the bracket member (7) by fitting the output spindle portion (12b) into the retaining cylinder (24).

7. 7. The electric brake device according to claim 6, The electric brake device is characterized in that the retaining cylinder (24) is provided with a press-fitting portion (25) into which the output spindle portion (12b) is press-fitted.

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