Electric braking device

Abstract

To provide an electrically-driven braking device configured so that restrictions on designing a circuit board can be reduced.SOLUTION: An electrically-driven braking device 30 comprises a plurality of electrically-driven cylinder devices 50A and 50B, and a circuit board 45 that controls electric motors 60 of the electrically-driven cylinder devices 50A and 50B. The plurality of electrically-driven cylinder devices 50A and 50B are arranged adjacently in an alignment direction which is a radial direction of pistons 56, with axis lines of the pistons 56 of the device made parallel with each other. The circuit board 45 is arranged adjacently to the plurality of electrically-driven cylinder devices 50A and 50B, in a posture in which a plate surface of the circuit board 45 is made to be parallel with the axis lines of the pistons 56 and a longitudinal direction thereof matched with the alignment direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electric braking device that generates braking force at a wheel by supplying brake fluid to a wheel cylinder. [Background technology]

[0002] The electric braking device described in Patent Document 1 includes an electric cylinder device that supplies and discharges brake fluid to multiple wheel cylinders, a housing that supports the electric cylinder device, a board case attached to the housing, and a circuit board housed in the board case. In this electric braking device, the housing is disposed between the board case and the housing of the electric motor that serves as the power source for the electric cylinder device. Furthermore, the cylinder of the electric cylinder device protrudes from the housing into the board case. Therefore, the circuit board is designed to avoid contact with the portion of the cylinder that protrudes into the board case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-113033 Summary of the Invention [Problem to be solved by the invention]

[0004] In the electric braking device described above, a part of the cylinder is located inside the circuit board case, so the circuit board must be designed to avoid contact between the cylinder and the circuit board, which places many constraints on the design of the circuit board. [Means for solving the problem]

[0005] An electric braking device that solves the above problems includes multiple electric cylinder devices that convert the rotational motion of an electric motor into linear motion that drives pistons in cylinders, and a circuit board that controls the electric motors, and adjusts the braking force applied to a vehicle by operating the electric cylinder devices. In this electric braking device, the multiple electric cylinder devices are arranged adjacent to each other in an alignment direction that is the radial direction of the pistons, with the axes of the pistons parallel to each other. The circuit board is arranged adjacent to the multiple electric cylinder devices, with its plate surface parallel to the axes of the pistons and its longitudinal direction facing the alignment direction.

[0006] Note that "the axes of the pistons are parallel to each other" means that the axes of the pistons are substantially parallel to each other, and includes cases where the axes are slightly misaligned due to manufacturing errors, assembly errors, etc. In the above configuration, the circuit board is arranged adjacent to the multiple electric cylinder devices. Therefore, the circuit board can be designed without taking into consideration the size and shape of the cylinders. This reduces the constraints on the design of the circuit board.

[0007] Furthermore, since the multiple electric cylinder devices are supported by the housing in a lined-up configuration, the dimensions of the electric braking device in the alignment direction tend to be large. Therefore, the circuit board is positioned relative to the housing with its longitudinal direction facing the alignment direction. This makes it possible to prevent the electric braking device from becoming too large. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a cross section of an electric braking device according to an embodiment and a schematic configuration of a friction brake provided on a wheel. [Figure 2] FIG. 2 is a perspective view of the electric braking device. [Figure 3] FIG. 3 is an exploded perspective view of the electric braking device. [Figure 4] FIG. 4 is a partially cutaway plan view of the electric braking device. [Figure 5] FIG. 5 is a schematic diagram showing the positional relationship between the axes of a plurality of cylinders and a circuit board in the electric braking device. [Figure 6] FIG. 6 is a perspective view that schematically shows an electric braking device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment in which the electric braking device is embodied in an electric braking device provided in a vehicle will be described below with reference to FIGS. 1 shows an electric braking device 30 of this embodiment, a plurality of wheels 11, and a plurality of friction brakes 20. One friction brake 20 is provided for each wheel 11.

[0010] <Friction Brake 20> The friction brake 20 includes a frictioned portion 21 that rotates integrally with the wheel 11, a friction portion 22, and a wheel cylinder 23. When brake fluid is supplied to the wheel cylinder 23 and the fluid pressure in the wheel cylinder 23 increases, the friction portion 22 is pressed against the frictioned portion 21. This generates a braking force on the wheel 11.

[0011] <Electric braking device 30> FIG. 2 is a perspective view showing the electric braking device 30. FIG. 2 shows a first axis X, a second axis Y, and a third axis Z, which are perpendicular to one another. Of the two directions along the first axis X, one is referred to as the first X-axis direction X1, and the other is referred to as the second X-axis direction X2. Of the two directions along the second axis Y, one is referred to as the first Y-axis direction Y1, and the other is referred to as the second Y-axis direction Y2. Of the two directions along the third axis Z, one is referred to as the first Z-axis direction Z1, and the other is referred to as the second Z-axis direction Z2. In this embodiment, the "direction along the axis" may be substantially the same as the direction in which the axis extends, and may be slightly different due to manufacturing errors, assembly errors, etc.

[0012] 1 and 2, the electric braking device 30 has an electric cylinder unit 300. The electric cylinder unit 300 includes a housing 31, a plurality of electric cylinder devices, a board case 40, and a circuit board 45. The electric cylinder unit 300 adjusts the braking force applied to the vehicle by operating electric cylinder devices 50A and 50B. In this embodiment, two electric cylinder devices 50A and 50B are provided.

[0013] <<Case 31>> As shown in Figures 1 and 3, the housing 31 supports two electric cylinder devices 50A, 50B. The housing 31 has insertion holes 32 that penetrate the housing 31 in a direction along the first axis X. The housing 31 has the same number of insertion holes 32 as the electric cylinder devices 50A, 50B. The two insertion holes 32 are aligned in a direction along the third axis Z. The housing 31 supports the two electric cylinder devices 50A, 50B in a manner such that portions of the electric cylinder devices 50A, 50B are housed within the insertion holes 32.

[0014] The housing 31 also supports other components for completing the brake system. Examples of the other components include solenoid actuators, pressure sensors, and other components connected to the circuit board 45. The housing 31 also functions as a fluid path connecting each component. For example, the housing 31 is provided with an oil port for connecting piping to the wheel cylinder 23, and fluid paths connecting the electric cylinder devices 50A, 50B to the solenoid actuators, pressure sensors, and the like.

[0015] The housing 31 has two side surfaces 33, 34 on which openings are formed by providing insertion holes 32 in the housing 31. Of the two side surfaces 33, 34, the side surface located in the first X-axis direction X1 is referred to as the support side surface 33, and the side surface located in the second X-axis direction X2 is referred to as the protruding side surface 34. The support side surface 33 and the protruding side surface 34 are, for example, planes perpendicular to the first axis X. Among the side surfaces of the housing 31, the side surface connecting the end of the support side surface 33 in the first Y-axis direction Y1 and the end of the protruding side surface 34 in the first Y-axis direction Y1 is referred to as the board-facing side surface 35. The solenoid actuator and pressure sensor described above are disposed on the board-facing side surface 35 and are electrically connected to a circuit board 45 provided in the board case 40.

[0016] <<Electric Cylinder Devices 50A, 50B>> 1, the electric cylinder devices 50A, 50B include an electric motor 60 as a power source, a rotation transmission mechanism 70, a linear motion conversion mechanism 80, a cylinder 51, and a piston 56. The electric cylinder devices 50A, 50B supply and discharge brake fluid to and from the wheel cylinder 23 by the linear motion of the piston 56 inside the cylinder 51 in response to the drive of the electric motor 60. In other words, the electric cylinder devices 50A, 50B convert the rotational motion of the electric motor 60 into linear motion inside the cylinder 51 that drives the piston 56.

[0017] The cylinder 51 is supported by the housing 31 while being inserted into the insertion hole 32. Therefore, the axis 51a of the cylinder 51 extends in the same direction as the axis of the insertion hole 32. In other words, the axis 51a of the cylinder 51 extends in a direction along the first axis X.

[0018] The cylinder 51 has a cylindrical main body 52, a bottom wall 53 that closes the end of the main body 52 in the second X-axis direction X2, and a flange 54 that is connected to the end of the main body 52 in the first X-axis direction X1. The flange 54 is in surface contact with the support side surface 33 of the housing 31. For example, as shown in FIG. 4, the flange 54 is fastened to the housing 31 with bolts.

[0019] 1 and 2, the main body portion 52 is inserted through the insertion hole 32. A tip portion of the main body portion 52, which is an end portion in the second X-axis direction X2, protrudes from the housing 31 in the second X-axis direction X2.

[0020] As described above, the two insertion holes 32 are aligned in the direction along the third axis Z, and therefore the two electric cylinder devices 50A, 50B are aligned in the direction along the third axis Z. Of the two electric cylinder devices 50A, 50B, one electric cylinder device (for example, the electric cylinder device 50A) is referred to as the "first electric cylinder device," and the other electric cylinder device (for example, the electric cylinder device 50B) is referred to as the second electric cylinder device. In this case, the direction along the third axis Z is an example of the radial direction of the cylinder 51 of the electric cylinder device 50A, which is the first electric cylinder device. In other words, the direction along the third axis Z corresponds to the "alignment direction" of the multiple electric cylinder devices 50A, 50B. Therefore, in this embodiment, the two electric cylinder devices 50A, 50B are supported by the housing 31 aligned in the above-mentioned alignment direction.

[0021] Furthermore, in the electric cylinder device 50A, which is the first electric cylinder device, the axis 51a of the cylinder 51 extends in a direction along the first axis X. Similarly, in the electric cylinder device 50B, which is the second electric cylinder device, the axis 51a of the cylinder 51 also extends in a direction along the first axis X. In other words, the multiple electric cylinder devices 50A, 50B are respectively arranged with the axes 51a of the cylinders 51 parallel to each other.

[0022] Here, the axis 51a of the cylinder 51 is also the axis of the piston 56. Furthermore, the radial direction of the cylinder 51 is also the radial direction of the piston 56. Therefore, in this embodiment, the multiple electric cylinder devices 50A, 50B are arranged adjacent to each other in the alignment direction, which is the radial direction of the pistons 56, with the axes of the pistons 56 parallel to each other.

[0023] When disassembling the electric cylinder unit 300, the cylinder 51 can be removed from the housing 31 by releasing the fixation between the flange 54 and the housing 31. That is, the two electric cylinder devices 50A, 50B are supported on the housing 31 in a manner that allows them to be removed from the housing 31 by moving the cylinder 51 relative to the housing 31 in the first X-axis direction X1. That is, in this embodiment, the first X-axis direction X1 corresponds to the "removal direction" in which the electric cylinder devices 50A, 50B are moved relative to the housing 31 when removing the electric cylinder devices 50A, 50B from the housing 31.

[0024] The piston 56 moves back and forth within the cylinder 51 in the direction of extension of the axis 51a of the cylinder 51. That is, the piston 56 is movable in the first X-axis direction X1 and the second X-axis direction X2. When the piston 56 moves in the second X-axis direction X2, brake fluid is supplied from within the cylinder 51 toward the wheel cylinder 23. On the other hand, when the piston 56 moves in the first X-axis direction X1, brake fluid is discharged from the wheel cylinder 23 toward the cylinder 51.

[0025] The electric motor 60 has a motor housing 61, a stator 62, a rotor 63, and an output shaft 64 that rotates integrally with the rotor 63. The motor housing 61 is disposed further in the first X-axis direction X1 than the casing 31. Specifically, the motor housing 61 is fixed to the cylinder 51 while being placed on the flange 54. The stator 62 and the rotor 63 are accommodated within the motor housing 61. The output shaft 64 protrudes outside the motor housing 61. The output shaft 64 extends in a direction along the first axis X. Therefore, the axis of the electric motor 60 extends in a direction along the axis 51a of the cylinder 51. Specifically, the electric motor 60 is disposed coaxially with the cylinder 51. In this embodiment, the output shaft 64 protrudes from the motor housing 61 in the second X-axis direction X2.

[0026] A motor angle sensor 66 that detects the rotation angle of the rotor 63 is provided inside the motor housing 61. For example, the motor angle sensor 66 is a resolver. The motor angle sensor 66 outputs a detection signal that corresponds to the rotation of the rotor 63 to the circuit board 45.

[0027] 3 and 4, in this embodiment, the electric motor 60 includes an extension portion 67 that extends radially outward from the motor housing 61. Specifically, the extension portion 67 extends from the motor housing 61 in the first Y-axis direction Y1. The extension portion 67 is provided with a male connector 68 that protrudes in the second X-axis direction X2, i.e., toward the board case 40. The male connector 68 is provided with a power receiving terminal electrically connected to the electric motor 60 and a sensor terminal to which a signal line of the motor angle sensor 66 is electrically connected.

[0028] The rotation transmission mechanism 70 transmits the rotational motion of the electric motor 60 to the linear motion conversion mechanism 80. Specifically, the rotation transmission mechanism 70 is a speed reduction mechanism that reduces the speed of the rotational motion of the electric motor 60 and transmits it to the linear motion conversion mechanism 80. For example, as shown in FIG. 1 , the rotation transmission mechanism 70 has a sun gear 71, a ring gear 72, and multiple pinion gears 73. The multiple pinion gears 73 mesh with both the sun gear 71 and the ring gear 72 and are capable of rotating and revolving. The sun gear 71 is connected to the output shaft 64 of the electric motor 60, so that the sun gear 71 rotates integrally with the output shaft 64. The multiple pinion gears 73 are connected to the linear motion conversion mechanism 80 via output pins 74.

[0029] The linear motion conversion mechanism 80 converts the rotational motion transmitted from the rotation transmission mechanism 70 into linear motion and outputs the linear motion to the piston 56. The linear motion conversion mechanism 80 is, for example, a ball screw mechanism or a feed screw mechanism. The linear motion conversion mechanism 80 has a rotating unit 81 to which a plurality of output pins 74 are connected, and a linear motion unit 82. When the rotational motion is transmitted from the plurality of output pins 74 to the rotating unit 81, the rotating unit 81 rotates, and the linear motion unit 82 moves linearly in a direction corresponding to the rotation direction of the rotating unit 81. When the linear motion unit 82 moves in the second X-axis direction X2, the piston 56 is pushed by the linear motion unit 82 and moves in the second X-axis direction X2. On the other hand, when the linear motion unit 82 moves in the first X-axis direction X1, the linear motion unit 82 pulls the piston 56 in the second X-axis direction X2, and further moves in the first X-axis direction X1 with the assistance of the hydraulic pressure in the cylinder 51. In this embodiment, a screw is used as the rotating part 81, and a nut disposed radially outside the screw is used as the linear motion part .

[0030] <<Board Case 40 and Circuit Board 45>> As shown in FIGS. 1 and 2, the board case 40 is generally rectangular and accommodates a circuit board 45 therein. The board case 40 is fixed to the housing 31. The direction along the first axis X is also the direction in which the axis 51a of the cylinder 51 of the electric cylinder device 50A, 50B extends, and the direction along the third axis Z is the alignment direction. Therefore, it can be said that the board case 40 is adjacent to the housing 31 in the direction along the second axis Y, which is perpendicular to both the first axis X and the third axis Z. In other words, as shown in FIGS. 3 and 4, the board case 40 is fixed to the housing 31 in an orientation facing the board-facing side surface 35. In this case, the dimension of the board case 40 in the direction along the third axis Z is larger than both the dimension of the board case 40 in the direction along the first axis X and the dimension of the board case 40 in the direction along the second axis Y. The dimension of the substrate case 40 in the direction along the first axis X is greater than the dimension of the substrate case 40 in the direction along the second axis Y.

[0031] The dimension of the board case 40 in the first Z-axis direction Z1 is larger than the dimension of the housing 31 in the first Z-axis direction Z1. A power connector 41 is disposed at the end of the board case 40 in the first Z-axis direction Z1. The power connector 41 protrudes from the board case 40 in the second Y-axis direction Y2 and is located further in the first Z-axis direction Z1 than the housing 31. Power is supplied to the circuit board 45 from an on-board power supply via the power connector 41.

[0032] A female connector 42 is provided on a side surface of the board case 40 at a position facing the extension portion 67 of the electric motor 60. In this embodiment, two electric motors 60 are provided, and therefore the two female connectors 42 are lined up in a direction along the third axis Z. A corresponding male connector 68 is mated with the female connector 42. That is, when the male connector 68 moves in the second X-axis direction X2, the male connector 68 is mated with the female connector 42. On the other hand, when the male connector 68 moves in the first X-axis direction X1 while mated with the female connector 42, the mating between the male connector 68 and the female connector 42 is released.

[0033] Female connector 42 is provided with a power transmission terminal and a sensor signal receiving terminal that are electrically connected to circuit board 45. When male connector 68 is mated with female connector 42, the power transmission terminal is connected to the power receiving terminal, and the sensor signal receiving terminal is connected to the sensor terminal. On the other hand, when male connector 68 moves relative to female connector 42 in the first X-axis direction X1 and the mating between male connector 68 and female connector 42 is released, the connection between the power transmission terminal and the power receiving terminal is released, and the connection between the sensor signal receiving terminal and the sensor terminal is released.

[0034] A control unit that controls the multiple electric motors 60 is mounted on the circuit board 45. As shown in FIGS. 1 and 5, the circuit board 45 has a rectangular plate shape. That is, the peripheral edge of the circuit board 45 has two first edges 45a extending in a direction along the third axis Z and two second edges 45b extending in a direction along the first axis X. The two first edges 45a are parallel to each other, and the two second edges 45b are parallel to each other. The length of at least one of the two first edges 45a is longer than the length of either of the two second edges 45b. Therefore, as shown in FIGS. 1 and 4, the circuit board 45 is disposed in an orientation in which the longitudinal direction of the plate surface 451 extends in a direction along the third axis Z and the lateral direction of the plate surface 451 extends in a direction along the first axis X.

[0035] 5 schematically illustrates the positional relationship between the axes 51a of the two cylinders 51 and the circuit board 45. As shown in FIG. 5, the axes 51a of the two cylinders 51 extend in a direction along the first axis X. Furthermore, the plate surface 451 of the circuit board 45 is parallel to both the first axis X and the third axis Z and is perpendicular to the second axis Y. In other words, the circuit board 45 is disposed with its plate surface 451 oriented parallel to the axes 51a of the cylinders 51.

[0036] <Actions and Effects of the Present Embodiment> (1) In this embodiment, the board case 40 is attached to the housing 31 in a manner such that it is adjacent to the housing 31 in the direction along the second axis Y. Therefore, the cylinders 51 of the multiple electric cylinder devices 50A, 50B are not located inside the board case 40. Because the circuit board 45 is housed inside such a board case 40, the shape of the circuit board 45 can be designed without considering the position of the cylinders 51. Therefore, constraints on the design of the circuit board 45 can be reduced.

[0037] Furthermore, the multiple electric cylinder devices 50A, 50B are supported by the housing 31 in a state where they are lined up in the direction along the third axis Z. Therefore, the dimension of the electric braking device 30 in the direction along the third axis Z tends to be large. Therefore, the board case 40 is attached to the housing 31 in an orientation where the longitudinal direction of the circuit board 45 faces in the direction along the third axis Z. This makes it possible to prevent the electric braking device 30 from becoming larger.

[0038] (2) In the electric cylinder devices 50A, 50B, the electric motor 60 is disposed so that the axis of the electric motor 60 extends in a direction along the axis 51a of the cylinder 51. Furthermore, no other members are disposed closer to the first X-axis direction X1 than the electric cylinder devices 50A, 50B. Therefore, the electric cylinder devices 50A, 50B can be easily moved in the first X-axis direction X1 relative to the housing 31. In other words, the electric cylinder devices 50A, 50B can be easily removed from the housing 31. Therefore, the work of replacing the electric cylinder devices 50A, 50B can be easily performed. Furthermore, the work of removing the electric motor 60 from the electric cylinder devices 50A, 50B can also be easily performed.

[0039] (3) The capacity of the wheel cylinder 23 differs depending on the type of vehicle equipped with the electric braking device 30. An electric cylinder device having a cylinder with a relatively large capacity is provided for an electric braking device 30 for a vehicle equipped with a large-capacity wheel cylinder 23. On the other hand, an electric cylinder device having a cylinder with a relatively small capacity is provided for an electric braking device 30 for a vehicle equipped with a small-capacity wheel cylinder 23.

[0040] An electric cylinder device equipped with a cylinder with a relatively large volume is referred to as a large-capacity electric cylinder device. An electric cylinder device equipped with a cylinder with a relatively small volume is referred to as a small-capacity electric cylinder device. In this case, consider a case where the same housing 31 is used for both the large-capacity electric cylinder device and the small-capacity electric cylinder device. In this case, in order to increase the capacity of the cylinder of the large-capacity electric cylinder device, the axial dimension of the cylinder of the large-capacity electric cylinder device will be made larger than the axial dimension of the cylinder of the small-capacity electric cylinder device.

[0041] In this embodiment, no other members are arranged closer to the second X-axis direction X2 than the housing 31. Therefore, cylinders with different dimensions in the direction along the first axis X can be attached to the housing 31.

[0042] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0043] The electric cylinder device may be one in which the axis of the electric motor 60 is offset from the axis 51a of the cylinder 51. In this case, the axis of the electric motor 60 may extend in a direction along the axis 51a of the cylinder 51. Furthermore, the electric motor 60 may be arranged so as to overlap with the cylinder 51 in the direction of the axis 51a of the cylinder 51. In this case, the electric braking device 30 can be made smaller in size in the direction of the axis 51a of the cylinder 51. Furthermore, the axis of the electric motor 60 may intersect with the axis 51a of the cylinder 51.

[0044] The electric braking device 30A shown in Fig. 6 includes a plurality of electric cylinder devices 150A, 150B in which the axis 60a of the electric motor 60 intersects with the axis 51a of the cylinder 51. In the electric cylinder devices 150A, 150B, the axis 60a of the electric motor 60 is perpendicular to the axis 51a of the cylinder 51.

[0045] The housing 31 may be configured so that the tip of the cylinder 51 can also be housed therein. The electric braking device may be configured with three or more electric cylinder devices aligned in a predetermined alignment direction. In this case, the electric braking device includes a plurality of second electric cylinder devices.

[0046] In the above embodiment, the electric cylinder devices 50A, 50B can be removed from the housing 31 by moving the electric cylinder devices 50A, 50B relative to the housing 31 in the first X-axis direction X1. However, the direction of relative movement of the electric cylinder devices 50A, 50B when removing the electric cylinder devices 50A, 50B from the housing 31 may be a direction different from the first X-axis direction X1. For example, the housing may be configured so that the electric cylinder devices 50A, 50B can be removed from the housing by moving the electric cylinder devices 50A, 50B relative to the housing in the second Y-axis direction Y2.

[0047] The shape of the circuit board 45 is not limited to the shape described in the above embodiment. That is, the circuit board 45 does not have to be rectangular as long as it has two first edges 45a that are parallel to each other and two second edges 45b that extend in a direction perpendicular to the first edges 45a, and the first edges 45a are longer than the second edges 45b. [Explanation of symbols]

[0048] 11...Wheel 23...Wheel cylinder 30,30A…Electric braking device 300...Electric cylinder unit 31...Case 40...Board case 45...Circuit board 451...Plate surface 50A, 50B, 150A, 150B... Electric cylinder device 51...Cylinder 51a...Axis line 56...Piston 60...Electric motor 60a…Axis line

Claims

1. An electric braking device comprising: a plurality of electric cylinder devices that convert the rotational motion of an electric motor into linear motion that drives pistons in cylinders; and a circuit board that controls the electric motors; and the electric braking device adjusts braking force applied to a vehicle by operating the electric cylinder devices, The plurality of electric cylinder devices are arranged adjacent to each other in an alignment direction, which is a radial direction of the pistons, with the axes of the pistons parallel to each other, The circuit board is disposed adjacent to the plurality of electric cylinder devices with the plate surface of the circuit board parallel to the axis of the piston and the longitudinal direction of the circuit board facing the alignment direction. Electric braking device.

2. The electric motor is disposed in such a position that the axis of the electric motor extends in a direction along the axis of the piston. The electric braking device according to claim 1 .

3. The electric motor is disposed in such a position that the axis of the electric motor intersects with the axis of the piston. The electric braking device according to claim 1 .

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