Electric braking device

Abstract

To miniaturize an electric braking device.SOLUTION: An electric motor (M) of the electric braking device is attached to a housing (20). The connecting portion (11A) and the reservoirs (11) are provided on an attachment surface (20A) of the housing (20) to which the electric motor (M) is attached, and are provided above the electric motor (M) in a vehicle-mounted posture which is a posture in which the electric braking device is mounted in the vehicle.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electric braking system. [Background technology]

[0002] Patent Document 1 discloses a technology in which the shape of the reservoir is devised in order to reduce the size of the brake unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-520392 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the reservoir is connected to the housing at a position closer to the ground than the master cylinder when the brake fluid is installed on the vehicle, the reservoir must be extended above the master cylinder in order to supply brake fluid to the master cylinder, which results in an increase in the size of the reservoir and therefore the brake unit. [Means for solving the problem]

[0005] In order to solve the above problems, one embodiment of the present disclosure provides an electric braking device that applies braking force to the wheels of a vehicle by supplying brake fluid stored in a reservoir to a wheel cylinder when driven by an electric motor, and includes a housing that defines at least a portion of a brake fluid path connecting the reservoir and the wheel cylinder, and a connection portion provided on the housing that connects the reservoir to the path defined by the housing, wherein the electric motor is attached to the housing, and the connection portion and the reservoir are provided on a mounting surface of the housing on which the electric motor is attached, and are provided above the electric motor in a vehicle mounting position in which the electric braking device is mounted on the vehicle. [Effects of the Invention]

[0006] According to one aspect of the present disclosure, the electric braking device can be made smaller. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a hydraulic circuit diagram for explaining an electric braking device according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram used to explain the installation position of a reservoir in the electric braking device according to the first embodiment of the present disclosure. [Figure 3] 3 is a cross-sectional view of FIG. 2 taken along line B-B. [Figure 4] FIG. 10 is a diagram used to explain the installation position of a reservoir in an electric braking device according to a second embodiment of the present disclosure. [Figure 5] 5 is a cross-sectional view taken along CC in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Embodiment 1] Fig. 1 is a hydraulic circuit diagram for explaining an electric braking device according to a first embodiment of the present disclosure. The electric braking device 1 shown in Fig. 1 includes a control unit 10, a reservoir 11, a check valve 12, a pressure supply device A, solenoid valves VL1 and VL2, and a wheel cylinder WC. The electric braking device 1 is mounted on, for example, a vehicle having a plurality of wheels W.

[0009] The pressure supply device A is an electric cylinder and includes a cylinder C, a piston P, an electric motor M, and a rotation angle sensor R. When the piston P moves linearly within the cylinder C in response to the drive of the electric motor M, the volume of the hydraulic chamber H defined by the cylinder C and the piston P changes. When the piston P moves forward within the cylinder C, the brake fluid within the hydraulic chamber H is discharged to the wheel cylinder WC. The rotation angle sensor R detects the rotation angle of the rotor of the electric motor M. The position of the piston P of the pressure supply device A can be obtained based on the detection result of the rotation angle sensor R.

[0010] The reservoir 11 stores brake fluid. The reservoir 11 is connected to the hydraulic chamber H of the pressure supply device A. A check valve 12 is arranged in the hydraulic path between the reservoir 11 and the hydraulic chamber H of the pressure supply device A. The check valve 12 allows the flow of brake fluid from the reservoir 11 to the pressure supply device A and restricts the flow of brake fluid from the pressure supply device A to the reservoir 11.

[0011] The solenoid valve VL1 opens and closes the fluid path between the hydraulic chamber H of the pressure supply device A and the wheel cylinder WC. When the solenoid valve VL1 is open, the hydraulic chamber H of the pressure supply device A and the wheel cylinder WC are in communication with each other. When the solenoid valve VL1 is closed, the hydraulic chamber H of the pressure supply device A and the wheel cylinder WC are cut off from each other.

[0012] The solenoid valve VL2 opens and closes the fluid path between the reservoir 11 and the wheel cylinder WC. When the solenoid valve VL2 is open, the reservoir 11 and the wheel cylinder WC are in communication with each other. When the solenoid valve VL2 is closed, the reservoir 11 and the wheel cylinder WC are not in communication with each other. The control unit 10 is, for example, an ECU including a microcomputer, and controls the electric motor M, the solenoid valves VL1 and VL2, etc. In the electric braking device 1, under the control of the control unit 10, the brake fluid stored in the reservoir 11 is supplied to the wheel cylinders WC by driving the electric motor M of the pressure supply device A. When the wheel cylinder pressure increases due to the brake fluid being supplied to the wheel cylinders WC, a braking torque corresponding to the wheel cylinder pressure is applied to the wheels W, and a braking force is applied to the vehicle.

[0013] Fig. 2 is a diagram used to explain the installation position of a reservoir in the electric braking device according to the first embodiment of the present disclosure. Fig. 2 schematically shows the area around the installation position of the electric motor M of the pressure supply device A in a vehicle having wheels W. Fig. 2 also shows examples of the up-down direction, left-right direction, and forward direction using arrows. The up-down direction is the top-to-bottom direction in the vehicle-mounted position of the electric braking device 1. The left-to-right direction is the width direction in the vehicle-mounted position of the electric braking device 1.

[0014] 2 shows a case 40 that houses the control unit 10. The case 40 has a connector 41 that supplies power and the like to the control unit 10 and the like. As shown in FIG. 2, the housing 20 is disposed on the left side of the case 40.

[0015] The housing 20 defines at least a portion of the brake fluid passage that connects the reservoir 11 and the wheel cylinder WC. The housing 20 is shaped, for example, like a rectangular parallelepiped. In FIG. 2, the brake fluid passage located inside the housing 20 is not shown for the sake of simplicity. The housing 20 is formed to have higher rigidity than the reservoir 11.

[0016] The housing 20 has a right side connected to the case 40 and a mounting surface 20A on its left side. The mounting surface 20A of the housing 20 is a surface that is perpendicular to the width direction of the vehicle (the left-right direction in FIG. 2) when the housing 20 is installed on the vehicle. The electric motor M of the pressure supply device A is attached to the mounting surface 20A with fastening members 21. The cylinder C and other components of the pressure supply device A extend from the mounting surface 20A to the right, passing through the inside of the housing 20 to reach the case 40. Wiring for supplying power to the electric motor M extends from the case 40 to the mounting surface 20A in the housing 20.

[0017] A reservoir 11 is disposed above the electric motor M of the pressure supply device A, which is connected to the housing 20. The length of the reservoir 11 in the left-right direction is approximately the same as the length of the electric motor M protruding leftward from the mounting surface 20A of the housing 20.

[0018] The reservoir 11 is connected to a fluid path in the housing 20 via a tank port 11A. The tank port 11A is an example of a connection part. The reservoir 11 and the tank port 11A are provided on a mounting surface 20A of the housing 20. A support part 30 is provided on the electric motor M, and the reservoir 11 is supported on the electric motor M via the support part 30.

[0019] Fig. 3 is a cross-sectional view taken along the line BB in Fig. 2. In Fig. 3, for the sake of simplicity, detailed illustration of the inside of the electric motor M is omitted. As shown in FIG. 3, the reservoir 11 defines a storage chamber 110 for storing brake fluid.

[0020] As shown in FIG. 3 , the support 30 is disposed between the electric motor M and the reservoir 11. The lower surface of the support 30 has a shape that fits into the shape of the upper portion of the protruding portion of the electric motor M that protrudes from the mounting surface 20A of the housing 20. For example, if the upper portion of the protruding portion of the electric motor M is a perfect circle, the lower surface of the support 30 is recessed into an arc shape with the same diameter as the protruding portion of the electric motor M. The upper surface of the support 30 has a shape that stabilizes the reservoir 11 that is placed and fixed thereon. For example, if the bottom surface of the reservoir 11 is a flat surface extending in the front-rear and left-right directions, the upper surface of the support 30 is also a flat surface extending in the front-rear and left-right directions. By disposing the support 30 between the electric motor M and the reservoir 11, the reservoir 11 can be supported in a stable position on the electric motor M regardless of the shape of the protruding portion of the electric motor M. Note that the reservoir 11 may be fixed to the support 30.

[0021] The support part 30 has a core part 31 extending in the vertical direction. The parts of the support part 30 other than the core part 31 are formed of an elastic material such as rubber. The lower end of the core part 31 abuts against a protruding part of the electric motor M, and the upper end abuts against the reservoir 11. The core part 31 is formed of a material with a higher thermal conductivity than the parts other than the core part 31, for example, a metal such as iron. Heat generated by the electric motor M is transferred to the reservoir 11 via the core part 31, and the brake fluid stored in the reservoir 11 is warmed. The heat transferred via the core part 31 reduces the viscosity of the brake fluid, improving the responsiveness of the electric braking device 1.

[0022] As explained using Figure 2, the left-right length of the reservoir 11 is approximately the same as the length of the electric motor M protruding leftward from the mounting surface 20A of the housing 20. As shown in Figure 3, the front-rear length of the reservoir 11 is equal to or less than the front-rear length of the housing 20. When the reservoir 11 is supported by the support part 30, the vertical length of the electric motor M, support part 30, and reservoir 11 is equal to or less than the vertical length of the housing 20. Therefore, the housing 20 to which the electric motor M and reservoir 11 are attached has a substantially cubic shape, which is less likely to restrict the layout of the vehicle when it is installed in the vehicle.

[0023] In the vehicle-mounted posture, the reservoir 11 is disposed rearward of the vehicle relative to the housing 20. That is, the front side surface 11F of the reservoir 11 is disposed rearward of the front side surface 20F of the housing 20. When the vehicle collides with an obstacle from the front, there is a high probability that the obstacle or vehicle-mounted component will collide with the housing 20, which is disposed forward of the reservoir 11, and the reservoir 11, which has lower rigidity than the housing 20, reduces the probability of colliding with the obstacle or vehicle-mounted component.

[0024] [Embodiment 2] Other embodiments of the present disclosure will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0025] The reservoir 11 of embodiment 2 differs from the electric braking device of embodiment 1 in that the cross-sectional area of ​​the storage chamber 110 in the front-to-back and left-to-right directions when mounted on the vehicle is smaller on the bottom side than on the top side.

[0026] Fig. 4 is a diagram used to explain the installation position of the reservoir in the electric braking device according to the second embodiment of the present disclosure. In Fig. 4, the left side surface of the reservoir 11 is recessed to the right near the electric motor M. Hereinafter, the part of the left side surface of the reservoir 11 that is located near the top surface 11U of the reservoir 11 will be referred to as the upper left side surface 11LU, and the part that is located near the electric motor M will be referred to as the lower left side surface 11LD.

[0027] In the reservoir 11 shown in Figure 4, the left-right distance L1 from the right side surface 11R of the reservoir 11 to the upper left side surface 11LU of the reservoir 11 is longer than the left-right distance L2 from the right side surface 11R of the reservoir 11 to the lower left side surface 11LD of the reservoir 11.

[0028] Figure 5 is a cross-sectional view taken along CC in Figure 4. As shown in Figure 5, the length of the reservoir 11 in the front-rear direction is the same near the top surface 11U and near the electric motor M. Therefore, the cross-sectional area of ​​the storage chamber 110 of the reservoir 11 in the front-rear, left-right direction is smaller near the electric motor M on the ground side in the vehicle-mounted posture than near the top surface 11U on the top side in the vehicle-mounted posture by (L1-L2) x the length in the front-rear direction.

[0029] The support part 30 is formed so that the length in the left-right direction is L1-L2, and is fitted into the space created by the lower left side surface 11LD being recessed to the right relative to the upper left side surface 11LU of the reservoir 11. The support part 30 can compactly support the reservoir 11, which has a small cross-sectional area in the front-rear and left-right directions near the electric motor M.

[0030] The tank port 11A is located on the right side surface 11R, closer to the electric motor M than the upper surface 11U. In FIG. 4, the tank port 11A is located in the vertical direction so that its left side surface is the lower left side surface 11LD. This allows brake fluid to be easily supplied from the tank port 11A even when the brake fluid stored in the reservoir 11 becomes low.

[0031] [Modification] In the first and second embodiments, the housing 20 has a rectangular parallelepiped shape, but is not limited to this. For example, the housing 20 may have a columnar shape with the mounting surface 20A as the bottom surface and side surfaces extending in the left-right direction. The shape of the mounting surface 20A is not limited to a rectangle. The mounting surface 20A may have any shape as long as it is a shape that allows the reservoir 11, the tank port 11A, and the electric motor M to be attached.

[0032] The shape of the reservoir 11 is not limited to the shapes shown in FIGS. The reservoir 11 in embodiment 1 can have any shape as long as (1) the length of the reservoir 11 protruding to the left from the mounting surface 20A is less than the amount of protrusion of the electric motor M, and (2) the reservoir 11 does not protrude from the housing 20 in the up-down or front-to-back directions when viewed from the left-right direction. The reservoir 11 according to the second embodiment can have any shape as long as it satisfies the above conditions (1) and (2) and (3) that the cross-sectional area of ​​the storage chamber 110 in the front-rear and left-right directions in the top-bottom direction when mounted on the vehicle is smaller on the bottom side than on the top side. The reservoir 11 according to the second embodiment may have, for example, a columnar shape whose side faces extend in the left-right direction and whose side faces are trapezoidal in shape with the bottom side shorter than the top side.

[0033] The support part 30 is not limited to those shown in Figures 2 to 5, as long as it supports the reservoir 11. For example, the support part 30 may be a spacer formed of an elastic material such as rubber without having a core part 31. The support part 30 may also be one that fixes the reservoir 11 to the electric motor M using a fastening member such as a screw.

[0034] The reservoir 11 may be supported by the electric motor M without the support portion 30. For example, the reservoir 11 may be shaped so that the lower surface thereof fits into the upper shape of the protruding portion of the electric motor M.

[0035] 〔summary〕 An electric braking device according to one aspect of the present disclosure is an electric braking device that applies braking force to the wheels of a vehicle by supplying brake fluid stored in a reservoir to a wheel cylinder when driven by an electric motor, and includes a housing that defines at least a portion of a brake fluid path connecting the reservoir and the wheel cylinder, and a connection portion provided on the housing that connects the reservoir to the fluid path defined by the housing, wherein the electric motor is attached to the housing, and the connection portion and the reservoir are provided on a mounting surface of the housing on which the electric motor is attached, and are provided above the electric motor in a vehicle mounting position in which the electric braking device is mounted on the vehicle. When an electric braking device having an electric motor attached to a housing is mounted on a vehicle, it is conceivable that a dead space will be created above the electric motor. According to the present disclosure, the connection portion and reservoir are provided on the electric motor mounting surface of the housing, and the electric braking device is provided above the electric motor when the vehicle is mounted. This configuration makes effective use of the dead space. Furthermore, because the reservoir and connection portion are located near the upper end of the mounting surface of the housing when the vehicle is mounted, it is easier to supply brake fluid from the reservoir to the fluid path. This prevents the reservoir from becoming larger, and ultimately allows the electric braking device to be made more compact.

[0036] In the electric braking device according to one aspect of the present disclosure, a support portion that supports the reservoir on an upper portion of the electric motor is provided. Since the reservoir is supported by the support portion, it is possible to improve resistance to shocks caused by the vehicle traveling.

[0037] In one aspect of the electric braking device of the present disclosure, the mounting surface of the housing is a surface perpendicular to the width direction of the vehicle when mounted on the vehicle, and the reservoir is positioned rearward of the vehicle relative to the housing when mounted on the vehicle. If the vehicle collides with an obstacle while moving forward, the obstacle or other vehicle mounted parts may collide with the electric braking device. According to the present disclosure, by positioning the reservoir behind the housing when the electric braking device is mounted on the vehicle, the above-mentioned obstacles and vehicle mounted components will collide with the housing, which has higher rigidity than the reservoir, thereby protecting the reservoir, which has lower rigidity than the housing.

[0038] In one aspect of the electric braking device of the present disclosure, the reservoir defines a storage chamber for storing the brake fluid, and the cross-sectional area of ​​the storage chamber in the vertical direction of the vehicle mounting position is smaller on the bottom side than on the top side. The cross-sectional area of ​​the reservoir chamber in the vertical direction of the electric braking device mounted on the vehicle is smaller on the bottom side than on the top side. This prevents the brake fluid level in the reservoir from falling below the connection part because the volume on the bottom side of the reservoir is small, even if the brake fluid level in the reservoir shakes due to a shock caused by the vehicle running. Therefore, the function of supplying brake fluid from the reservoir can be achieved without enlarging the reservoir.

[0039] [Additional Notes] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. [Explanation of symbols]

[0040] 1 Electric braking device 11 Reservoir 11A Tank port (connection) 20. Housing 20A Mounting surface 30 Support part 110 Storage chamber L1, L2 distance M Electric Motor W wheels WC Wheel Cylinder

Claims

1. An electric braking device that applies braking force to vehicle wheels by supplying brake fluid stored in a reservoir to wheel cylinders by driving an electric motor, a housing defining at least a portion of a brake fluid passage connecting the reservoir and the wheel cylinder; a connection portion provided in the housing and connecting the reservoir and a fluid path defined by the housing; the electric motor is mounted to the housing; the connecting portion and the reservoir are provided on a mounting surface of the housing on which the electric motor is mounted, and are provided above the electric motor when the electric braking device is mounted on the vehicle.

2. 2. The electric braking device according to claim 1, further comprising a support portion for supporting the reservoir above the electric motor when the electric braking device is mounted on the vehicle.

3. 2. The electric braking device according to claim 1, wherein the mounting surface of the housing is a surface perpendicular to a width direction of the vehicle when the electric braking device is mounted on the vehicle, and the reservoir is disposed rearward of the vehicle relative to the housing when the electric braking device is mounted on the vehicle.

4. The reservoir defines a storage chamber for storing the brake fluid, 4. The electric braking device according to claim 1, wherein a cross-sectional area of ​​the storage chamber in the vertical direction when the device is mounted on the vehicle is smaller on the bottom side than on the top side.

Images