Braking device

Abstract

As an example, we can obtain a braking system that improves the design flexibility of the electronic control unit. [Solution] The braking device according to the embodiment includes, as an example, a pressure sensor having a pressure source, an electric motor that drives the pressure source, a coupling circuit, and a ground terminal electrically connected to the coupling circuit; a housing that supports the pressure source and the electric motor; an electronic control unit that controls the pressure source and is electrically connected to the ground terminal; a case that is attached to the housing and houses the electronic control unit; and a connector that is electrically connected to the electronic control unit and configured to be connected to an external device, wherein the coupling circuit has at least one capacitor, and a plurality of noises with different frequencies flow to the external device via the coupling circuit, the ground terminal, the electronic control unit, and the connector.

Description

Technical Field

[0001] An embodiment of the present invention relates to a braking device.

Background Art

[0002] Conventionally, a braking device is known that includes a wheel cylinder that presses a friction member against a rotating body by the pressure of brake fluid, a pressure source that adjusts the pressure of the brake fluid in the wheel cylinder, an electric motor that drives the pressure source, and an electronic control unit (ECU) that controls the electric motor. The ECU is electrically connected to the vehicle body via various components, and causes noise to flow to the vehicle body (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional configuration, the ECU is provided with a terminal for causing noise to flow to the vehicle body. In the design of the ECU, providing such a terminal may restrict the arrangement of other components and wirings.

[0005] The present invention has been made in view of the above circumstances, and provides a braking device that can improve the degree of freedom (flexibility) in designing an electronic control unit.

Means for Solving the Problems

[0006] A braking device according to an embodiment of the present invention includes, as an example, a wheel cylinder, a pressure source configured to pressurize the brake fluid in the wheel cylinder, an electric motor configured to drive the pressure source, a pressure sensor having a signal terminal configured to detect the fluid pressure in the brake fluid path between the wheel cylinder and the pressure source and to output an electrical signal corresponding to the fluid pressure, a coupling circuit, and a ground terminal electrically connected to the coupling circuit, a housing supporting the pressure source and the electric motor, an electronic control unit controlling the pressure source and electrically connected to the signal terminal and the ground terminal, a case mounted on the housing and housing the electronic control unit, and a connector electrically connected to the electronic control unit and configured to connect to an external device, wherein the coupling circuit has at least one capacitor, and multiple noises with different frequencies flow to the external device via the coupling circuit, the ground terminal, the electronic control unit, and the connector. Therefore, as an example, by having at least one capacitor in the coupling circuit, noise corresponding to the frequency characteristics of the capacitor can be removed. Multiple noises are discharged from a single grounding terminal of the pressure sensor to an external device via the electronic control unit and connector. In other words, the electronic control unit can eliminate multiple noises by having only one terminal electrically connected to the grounding terminal. The number of terminals on the electronic control unit does not need to increase from the conventional number. Therefore, compared to a case where the electronic control unit is provided with multiple terminals that carry different types of noise, the braking device can reduce the number of terminals on the electronic control unit and improve the design flexibility of the electronic control unit. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic cross-sectional view showing a brake system according to the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing a part of the hydraulic control device of the first embodiment. [Figure 3]Figure 3 is a schematic circuit diagram showing a part of the hydraulic control device of the first embodiment. [Figure 4] Figure 4 is a schematic circuit diagram showing a part of the hydraulic control device according to the second embodiment. [Figure 5] Figure 5 is a schematic cross-sectional view showing a hydraulic control device according to the third embodiment. [Modes for carrying out the invention]

[0008] (First embodiment) The first embodiment will be described below with reference to Figures 1 to 3. Note that in this specification, the components of the embodiment and their descriptions may be described using multiple expressions. The components and their descriptions are examples and are not limited by the expressions used herein. Components may also be identified by names different from those used herein. Furthermore, components may also be described using expressions different from those used herein.

[0009] In the following explanation, “suppress” is defined, for example, to prevent the occurrence of an event, action, or effect, or to reduce the degree of an event, action, or effect. Also, in the following explanation, “restrict” is defined, for example, to prevent movement or rotation, or to permit movement or rotation within a predetermined range while preventing movement or rotation beyond that predetermined range.

[0010] Figure 1 is a schematic cross-sectional view showing a brake system 10 according to a first embodiment. As shown in Figure 1, the brake system 10 is mounted on a vehicle 1 such as a four-wheeled automobile. The brake system 10 is an example of a braking device.

[0011] The brake system 10 includes a hydraulic control device 11, a plurality of wheel cylinders 12, a reservoir 13, and an external device 14. The brake system 10 may further include brake pads, a stroke sensor, and various other components.

[0012] The hydraulic control device 11 controls, for example, the pressure of the brake fluid (hydraulic pressure) in at least one of the multiple wheel cylinders 12. Each of the multiple wheel cylinders 12, for example, uses hydraulic pressure to press a friction member, such as a brake pad, against a rotating body, such as a disc rotor, thereby generating braking force for the vehicle 1.

[0013] The reservoir 13 stores brake fluid. The external device 14 is, for example, the electronic control unit (ECU) of the brake system 10 and controls the hydraulic pressure control device 11. The external device 14 receives power from the vehicle's battery and is grounded to the vehicle body. Note that the external device 14 may be any other device.

[0014] The hydraulic control device 11 includes a housing 21, an electric motor 22, an electric cylinder 23, a solenoid valve 24, an electronic control unit (ECU) 25, a grounding pin 26, a case 27, and a connector 28.

[0015] As shown in each drawing, the X-axis and Y-axis are defined herein for convenience. The X-axis and Y-axis are orthogonal to each other. The X-axis is provided along the width of the hydraulic control device 11. The Y-axis is provided along the depth of the hydraulic control device 11.

[0016] Furthermore, the X and Y directions are defined herein. The X direction is a direction along the X axis and includes the +X direction indicated by the X-axis arrow and the -X direction which is the opposite direction of the X-axis arrow. The Y direction is a direction along the Y axis and includes the +Y direction indicated by the Y-axis arrow and the -Y direction which is the opposite direction of the Y-axis arrow.

[0017] The housing 21 is a conductive component made of a metal such as an aluminum alloy. The housing 21 is formed in a substantially rectangular parallelepiped shape. However, the housing 21 may be formed in other shapes. The housing 21 is attached to the body of the vehicle 1, for example.

[0018] The housing 21 has a front surface 21a, a back surface 21b, and a concave surface 21c. Note that the terms front, back, left, right, up, and down in the present embodiment are used for convenience, and do not limit the direction, position, and usage mode.

[0019] The front surface 21a is the end face of the housing 21 in the -Y direction. The front surface 21a is formed to be substantially flat and faces the -Y direction. The back surface 21b is located on the opposite side of the front surface 21a. That is, the back surface 21b is the end face of the housing 21 in the +Y direction. The back surface 21b is formed to be substantially flat and faces the +Y direction. Note that the front surface 21a and the back surface 21b may face other directions.

[0020] The concave surface 21c is recessed from the front surface 21a in the substantially +Y direction. The concave surface 21c, together with the front surface 21a, is located on the side opposite to the back surface 21b. The concave surface 21c is closer to the back surface 21b than the front surface 21a is.

[0021] Figure 2 is a cross-sectional view schematically showing a part of the hydraulic control device 11 according to the first embodiment. The housing 21 is provided with the two mounting holes 31 and 32, the plurality of flow passages 33, 34, and 35, and the plurality of screw holes 36 shown in Figure 1, as well as the through hole 37 and the recess 38 shown in Figure 2. Further, the housing 21 may be provided with various other holes and flow passages.

[0022] As shown in Figure 1, the mounting hole 31 is recessed from the front surface 21a of the housing 21 in the +Y direction. The mounting hole 32 is recessed from the back surface 21b of the housing 21 in the -Y direction. Note that the mounting holes 31 and 32 may be provided on other surfaces of the housing 21.

[0023] One end of the flow passage 33 communicates with the mounting hole 31. The other end of the flow passage 33 is connected to the reservoir 13 via, for example, a pipe. The flow passage 34 allows the two mounting holes 31 and 32 to communicate with each other. One end of the flow passage 35 communicates with the mounting hole 32. The other end of the flow passage 35 is connected to the wheel cylinder 12 via, for example, a pipe. Note that various components such as solenoid valves may be provided in the flow passages 33, 34, and 35.

[0024] Multiple screw holes 36 are recessed in the +Y direction from the front surface 21a of the housing 21. The multiple screw holes 36 are arranged around the mounting holes 31. As shown in Figure 2, the through hole 37 penetrates the housing 21 so as to open to the rear surface 21b and the concave surface 21c. The recess 38 is provided around the through hole 37 and is recessed in the +Y direction from the concave surface 21c.

[0025] As shown in Figure 1, the electric motor 22 is mounted on the front surface 21a of the housing 21. The electric motor 22 includes a motor case 41, a stator 42, a rotor 43, a motor shaft 44, and a gasket 45.

[0026] The motor case 41 houses the stator 42, the rotor 43, and a portion of the motor shaft 44. The motor case 41 is located at least partially outside the housing 21. The motor case 41 has a cylindrical wall 51, an end wall 52, and a flange 53.

[0027] The cylindrical wall 51 is formed in a substantially cylindrical shape extending around the axis Ax of the electric motor 22. The axis Ax extends substantially in the Y direction. In this embodiment, the axis Ax substantially coincides with the central axis of the mounting hole 31. Note that the central axis of the mounting hole 31 and the axis Ax may be different from each other.

[0028] The cylindrical wall 51 has an inner circumferential surface 51a and an outer circumferential surface 51b. The inner circumferential surface 51a and the outer circumferential surface 51b are curved surfaces that extend around the axis Ax. The inner circumferential surface 51a faces the axis Ax. The outer circumferential surface 51b is located on the opposite side of the inner circumferential surface 51a.

[0029] The end wall 52 closes the end of the cylindrical wall 51 in the -Y direction. The flange 53 protrudes from the end of the outer peripheral surface 51b in the +Y direction. Multiple through holes 55 are provided in the flange 53. The multiple through holes 55 are arranged around the axis Ax and communicate with multiple screw holes 36.

[0030] For example, a screw 56 passes through the through hole 55 and is fitted into the screw hole 36 of the housing 21. This allows the screw 56 to attach the motor case 41 to the housing 21. In other words, the housing 21 supports the electric motor 22. The motor case 41 covers the mounting hole 31.

[0031] The stator 42 surrounds the rotor 43 and motor shaft 44 inside the motor case 41. The rotor 43 is coupled to the motor shaft 44. For example, when the stator 42 is excited by a drive current, the rotor 43 and motor shaft 44 rotate around the axis Ax relative to the housing 21. The motor shaft 44 extends along the axis Ax and protrudes from the motor case 41 in the +Y direction. A portion of the motor shaft 44 is housed in a mounting hole 31.

[0032] The gasket 45 is interposed between the front surface 21a of the housing 21 and the flange 53. The gasket 45 liquid-tightly seals the gap between the housing 21 and the flange 53, preventing liquids or dust from entering the inside of the housing 21 and the electric motor 22.

[0033] The electric cylinder 23 is housed in a mounting hole 31 of the housing 21. The housing 21 further has an inner circumferential surface 21d that defines the mounting hole 31. The inner circumferential surface 21d is formed in a substantially cylindrical shape extending around the axis Ax and facing the axis Ax. The flow paths 33 and 34 each open into the inner circumferential surface 21d. The inner circumferential surface 21d of the housing 21 supports the electric cylinder 23. Other parts of the housing 21 may also support the electric cylinder 23.

[0034] The electric cylinder 23 is an example of a pressure source and can pressurize brake fluid. The pressure source may be other devices such as a pump. The electric cylinder 23 includes a piston 61, two ring seals 62 and 63, a linear motion member 64, a rotating member 65, and a reduction gear 66.

[0035] The piston 61 is formed in a substantially cylindrical shape, extending along the axis Ax and having its end closed in the +Y direction. The piston 61 is fitted into the mounting hole 31 so as to be movable in the Y direction relative to the housing 21.

[0036] The piston 61 partitions a portion of the mounting hole 31 as a fluid chamber R. The fluid chamber R is located between the piston 61 and the end of the mounting hole 31 in the +Y direction. The ring seals 62 and 63 seal the gap between the inner circumferential surface 21d of the housing 21 and the piston 61, preventing brake fluid from leaking out of the fluid chamber R. The two ring seals 62 and 63 are spaced apart from each other in the Y direction.

[0037] The flow path 33 communicates with the gap between the inner circumferential surface 21d of the housing 21 and the piston 61, between the two ring seals 62 and 63. When the piston 61 is in its initial position, the flow path 33 communicates with the liquid chamber R, for example, through a groove provided in the piston 61. The reservoir 13 is open to the atmosphere, for example. Therefore, when the piston 61 is in its initial position, the liquid pressure in the liquid chamber R is approximately equal to atmospheric pressure. The flow path 34 communicates with the liquid chamber R.

[0038] The linear motion member 64 is, for example, a nut. The linear motion member 64 is formed in a substantially cylindrical shape extending around the axis Ax and is provided with an internal thread (nut thread).

[0039] The linear motion member 64 is housed in the mounting hole 31 so as to be movable in the Y direction relative to the housing 21. The housing 21 holds the linear motion member 64 so as to restrict it from rotating about its axis Ax relative to the housing 21.

[0040] At least a portion of the linear motion member 64 is fitted inside the piston 61. This allows the linear motion member 64 to move integrally with the piston 61 in the +Y direction relative to the housing 21. The linear motion member 64 may also be movable integrally with the piston 61 in the -Y direction relative to the housing 21, or it may be able to move away from the piston 61 in the -Y direction.

[0041] The rotating member 65 is, for example, a screw shaft. The rotating member 65 extends along the axis Ax. The rotating member 65 is provided with an external thread (bolt thread).

[0042] The linear motion member 64 is attached to the rotating member 65 by the engagement of the female thread of the linear motion member 64 with the male thread of the rotating member 65. The linear motion member 64 and the rotating member 65 may form a ball screw with a ball interposed between the male and female threads. Alternatively, the linear motion member 64 may have a screw shaft and the rotating member 65 may have a nut.

[0043] The reduction gear 66 is, for example, a planetary gear mechanism and has a sun gear, a planetary carrier, multiple planetary gears, and a ring gear. However, the reduction gear 66 may be any other reduction mechanism.

[0044] For example, the sun gear of the reduction gear 66 is coupled to the motor shaft 44, the planetary carrier is coupled to the rotating member 65, and the ring gear is coupled to the housing 21. Multiple planetary gears are mounted on the planetary carrier spaced apart from each other around the axis Ax. In this way, the reduction gear 66 transmits rotation between the motor shaft 44 and the rotating member 65.

[0045] The solenoid valve 24 opens and closes the brake fluid path between the wheel cylinder 12 and the electric cylinder 23, or adjusts the fluid pressure. The solenoid valve 24 includes a valve 71, a solenoid coil 72, a solenoid terminal 73, a pressure sensor 74, and three springs 75, 76, and 77.

[0046] The valve 71 is fitted into the mounting hole 32 and attached to the housing 21, for example, by crimping. A portion of the valve 71 protrudes in the +Y direction from the back surface 21b of the housing 21.

[0047] The valve 71 includes, for example, a plunger, a valve body, and a seating surface. For example, the plunger is driven by a magnetic field, which presses the valve body against the seating surface. This causes the valve body to close an orifice provided on the seating surface, thereby closing the brake fluid path between the wheel cylinder 12 and the electric cylinder 23. Note that the valve 71 is not limited to this example, and the plunger driven by the magnetic field may also pull the valve body away from the seating surface.

[0048] The solenoid coil 72 surrounds the valve 71 and is supported, for example, on the back surface 21b of the housing 21. The solenoid coil 72 is energized by the drive current and generates a magnetic field that drives the plunger of the valve 71. The solenoid terminal 73 extends from the solenoid coil 72 in the +Y direction.

[0049] The pressure sensor 74 detects the fluid pressure in the brake fluid path between the wheel cylinder 12 and the electric cylinder 23. For example, the pressure sensor 74 is attached to the valve 71 and detects the fluid pressure in the space inside the valve 71 (the upstream space) that communicates with the fluid chamber R.

[0050] Figure 3 is a schematic circuit diagram showing a part of the hydraulic pressure control device 11 of the first embodiment. As shown in Figure 3, the pressure sensor 74 has a power terminal 81, a signal terminal 82, a ground terminal 83, a chassis ground terminal 84, and a coupling circuit 85. The pressure sensor 74 further has other circuits, for example, for detecting hydraulic pressure. However, for convenience, various circuits of the pressure sensor 74 are omitted in Figure 3.

[0051] The power terminal 81 is electrically connected to the spring 75. The signal terminal 82 is electrically connected to the spring 76. The ground terminal 83 is electrically connected to the spring 77. The chassis ground terminal 84 is electrically connected to the housing 21.

[0052] The coupling circuit 85 is provided between the grounding terminal 83 and the chassis ground terminal 84. In other words, the grounding terminal 83 and the chassis ground terminal 84 are electrically connected to the coupling circuit 85.

[0053] The coupling circuit 85 has two capacitors 87 and 88. The coupling circuit 85 may have one capacitor, or three or more capacitors. Furthermore, the coupling circuit 85 may have other wiring and components.

[0054] The grounding terminal 83 is electrically connected to one terminal of capacitor 87 and one terminal of capacitor 88. The chassis ground terminal 84 is electrically connected to the other terminal of capacitor 87 and the other terminal of capacitor 88. Therefore, the grounding terminal 83 is electrically connected to the housing 21 via capacitors 87 and 88 and the chassis ground terminal 84.

[0055] The ECU 25 controls the electric motor 22 and the solenoid valve 24. The ECU 25 may also control other components of the hydraulic control device 11. As shown in Figure 1, the ECU 25 has a circuit board 91 and a number of electronic components 92.

[0056] The circuit board 91 is, for example, a printed circuit board (PCB). However, the circuit board 91 may be of other types. The circuit board 91 is spaced apart from the housing 21 in the +Y direction. The back surface 21b of the housing 21 faces the circuit board 91.

[0057] The circuit board 91 is provided with a plurality of terminals 101, 102, 103, 104, 105, 106, 107, 108 as shown in Figure 3, and terminal 109 as shown in Figure 1. Terminals 101, 102, 103, 104, 105, 106, 107, 108, 109 are, for example, through-holes. Terminals 101, 102, 103 may be other terminals such as pads.

[0058] Terminal 101 is electrically connected to spring 75. That is, terminal 101 of ECU25 is electrically connected to power terminal 81 of pressure sensor 74 via spring 75. Terminal 102 is electrically connected to spring 76. That is, terminal 102 of ECU25 is electrically connected to signal terminal 82 via spring 76. Terminal 103 is electrically connected to spring 77. That is, terminal 103 of ECU25 is electrically connected to ground terminal 83 via spring 77.

[0059] As shown in Figure 1, the solenoid terminal 73 of the solenoid valve 24 is coupled to the terminal 109 of the substrate 91, for example, by press-fit. This electrically connects the solenoid valve 24 to the ECU 25.

[0060] Multiple electronic components 92 are mounted on the circuit board 91. These multiple electronic components 92 include, for example, a microcontroller that controls the electric motor 22 and the solenoid valve 24, and multiple transistors that generate the drive current for the electric motor 22. Note that the electronic components 92 are not limited to this example.

[0061] As shown in Figure 2, the grounding pin 26 has a pin 111 and a leaf spring 112. The pin 111 is coupled to the terminal 104 of the substrate 91, for example, by press-fit. As a result, the grounding pin 26 protrudes from the substrate 91 toward the housing 21 in the -Y direction. The leaf spring 112 is provided, for example, at the end of the pin 111 in the -Y direction. The leaf spring 112 is formed, for example, in a plate shape that spreads in a direction intersecting the Y direction. Alternatively, instead of having a leaf spring 112, the end of the pin 111 in the -Y direction may be bent elastically.

[0062] As shown in Figure 1, the case 27 houses the solenoid valve 24, the ECU 25, and the grounding pin 26. The case 27 has a base 121, a nut 122, a number of pins 123, and a cover 124. Note that the case 27 is not limited to this example.

[0063] The base 121 is made of, for example, synthetic resin. The base 121 is positioned on the back surface 21b of the housing 21. The nut 122 is formed integrally with the base 121, for example, by insert molding. Note that the nut 122 may be a different part from the base 121.

[0064] The base 121 of case 27 is attached to the housing 21. As shown in Figure 2, the hydraulic control device 11 further includes a screw 131, a waterproof washer 132, and a gasket 133.

[0065] The screw 131 is a conductive component made of metal. The screw 131 has a screw shaft 135 and a screw head 136. The screw shaft 135 fits into the nut 122 through the through hole 37 in the housing 21. The screw head 136 is located at the end of the screw shaft 135 in the -Y direction and abuts against the concave surface 21c of the housing 21. In this way, the screw 131 attaches the base 121 to the back surface 21b of the housing 21.

[0066] The screw shaft 135 passes through the nut 122 and is partially housed inside the case 27. Inside the case 27, the screw shaft 135 contacts the leaf spring 112 of the grounding pin 26. This electrically connects the housing 21 to the grounding pin 26 via the screw 131.

[0067] The leaf spring 112 contacts the screw 131 and undergoes elastic deformation when pressed by the screw 131. Therefore, even if there are variations in the dimensions and positions of the screw 131 and the grounding pin 26, the leaf spring 112 can reliably contact the screw shaft 135. The leaf spring 112 remains in contact with the screw 131 due to its elastic force.

[0068] The waterproof washer 132 is fitted into the recess 38 and interposed between the housing 21 and the screw head 136. For example, the waterproof washer 132 has a metal portion that contacts the screw head 136 and a resin portion that is interposed between the metal portion and the housing 21. The resin portion is compressed between the metal portion and the housing 21. Due to the elastic force of the resin portion, the waterproof washer 132 is pressed against the housing 21 and the screw 131. As a result, the waterproof washer 132 liquid-tightly seals the gap between the housing 21 and the screw 131.

[0069] The diameter of the screw head 136 is larger than the outer diameter of the waterproof washer 132. Also, the diameter of the screw head 136 is larger than the diameter of the recess 38. Therefore, the screw head 136 can contact the recess 21c of the housing 21.

[0070] The gasket 133 is interposed between the rear surface 21b of the housing 21 and the base 121. This allows the gasket 133 to liquid-tightly seal the gap between the rear surface 21b and the base 121. The gasket 133 may be formed, for example, in an annular shape and surround the screw 131.

[0071] As shown in Figure 1, the multiple pins 123 are formed integrally with the base 121, for example by insert molding, and protrude from the base 121. Note that the multiple pins 123 may be made of different parts from the base 121.

[0072] Multiple pins 123 are electrically connected to the stator 42 by being coupled to the busbar of the electric motor 22. Multiple pins 123 are coupled to terminals 105 and 106 of the circuit board 91, for example by press-fit. As a result, the electric motor 22 is electrically connected to the ECU 25, as shown in Figure 3.

[0073] As shown in Figure 1, the cover 124 is attached to the base 121. The ECU 25 is located between the base 121 and the cover 124. The ECU 25 may be supported by, for example, press-fit pins to the case 27, screwed to the base 121, or sandwiched between the base 121 and the cover 124.

[0074] The connector 28 protrudes, for example, from the base 121 of the case 27 in the -Y direction. The connector 28 has a plurality of connector pins 141, 142. The connector pins 141, 142 are coupled, for example, by press-fit to terminals 107, 108 of the substrate 91. In this way, the plurality of connectors 28 are electrically connected to the ECU 25.

[0075] Connector 28 is electrically connected to the external device 14, for example, via harness H. This allows the external device 14 to supply power to terminal 107 of the ECU 25 via harness H and connector 28, and to ground terminal 108 of the ECU 25.

[0076] The external device 14 controls the ECU 25 to drive the electric motor 22 and the solenoid valve 24. For example, the external device 14 transmits electrical signals to the ECU 25 through the harness H and connector 28.

[0077] The ECU 25 generates a drive current from the power supplied to terminal 107 based on an electrical signal input from the external device 14, and applies this drive current to the stator 42 of the electric motor 22. In other words, the ECU 25 is controlled by the external device 14 and drives the electric motor 22.

[0078] The external device 14 transmits an electrical signal to the ECU 25, for example, in accordance with the stroke of the brake pedal. The ECU 25 drives the electric motor 22 and the solenoid valve 24 in accordance with the electrical signal.

[0079] The electric motor 22 rotates the motor shaft 44, which in turn rotates the rotating member 65 around the axis Ax via the reduction gear 66. As a result, the linear member 64 and the piston 61 move in the Y direction according to the rotation direction of the motor shaft 44. In other words, the electric motor 22 drives the electric cylinder 23.

[0080] By moving in the +Y direction, the piston 61 blocks the passage between the flow path 33 and the fluid chamber R. By moving further, the piston 61 reduces the volume of the fluid chamber R. This allows the electric cylinder 23 to pressurize the brake fluid in the fluid chamber R and the wheel cylinder 12.

[0081] On the other hand, the piston 61 moves in the -Y direction, thereby increasing the volume of the fluid chamber R. This allows the electric cylinder 23 to reduce the hydraulic pressure in the fluid chamber R and the wheel cylinder 12.

[0082] As described above, the hydraulic control device 11 controls the hydraulic pressure of the wheel cylinder 12, for example, in response to the driver's operation of the brake pedal. This allows the brake system 10 to brake the vehicle 1.

[0083] The pressure sensor 74 detects the fluid pressure (hereinafter referred to as the detected pressure) in the brake fluid path between the wheel cylinder 12 and the electric cylinder 23, and outputs an electrical signal corresponding to the detected pressure from the signal terminal 82. The ECU 25 obtains the detected pressure by acquiring this electrical signal from the signal terminal 82 via the spring 76. The ECU 25 controls the electric motor 22 according to the detected pressure and can set the fluid pressure of the wheel cylinder 12 to a desired pressure.

[0084] The ECU 25 generates a drive current from the power supplied to terminal 107 based on a control signal input from the external device 14, and applies this drive current to the solenoid coil 72 of the solenoid valve 24. In other words, the ECU 25 is controlled by the external device 14 and drives the solenoid valve 24.

[0085] The solenoid valve 24 can create a pressure difference between the fluid chamber R and at least one of the multiple wheel cylinders 12 by, for example, adjusting the distance between the valve body and the seating surface of the valve 71. This allows the brake system 10 to individually control the braking force on multiple wheels.

[0086] In the hydraulic control device 11, noise is generated due to various causes. The hydraulic control device 11 can eliminate multiple noises with different frequencies by diverting them to the external device 14 using the coupling circuit 85.

[0087] For example, the pressure sensor 74 removes noise generated by the pressure sensor 74 (hereinafter referred to as the first noise) using the coupling circuit 85, thereby preventing the first noise from being included in the electrical signal output from the signal terminal 82. As an example, the frequency of the first noise is in the MHz range. Note that the first noise is not limited to this example.

[0088] The capacitor 87 of the coupling circuit 85 has a resonant frequency corresponding to the frequency of the first noise. Therefore, the first noise generated at the pressure sensor 74 flows to the external device 14 via the capacitor 87 of the coupling circuit 85, the ground terminal 83, the spring 77, terminal 103 on the ECU 25, the ground wiring and terminal 108 on the circuit board 91, and the connector 28. The first noise is then discharged from the external device 14 to the vehicle body of the vehicle 1.

[0089] Furthermore, when the electric motor 22 is driven, noise (hereinafter referred to as the second noise) is generated from the electric motor 22. For example, the second noise is radiated from the electric motor 22 and conducted to the housing 21. The second noise is input to the coupling circuit 85 from the chassis ground terminal 84 of the pressure sensor 74.

[0090] The frequency of the second noise is, for example, a frequency corresponding to the carrier frequency of the electric motor 22. As an example, the frequency of the second noise is in kHz units. However, the frequency of the second noise is not limited to this example.

[0091] The capacitor 88 of the coupling circuit 85 has a resonant frequency corresponding to the frequency of the second noise. Therefore, the second noise flows to the external device 14 via the housing 21, the chassis ground terminal 84, the capacitor 88 of the coupling circuit 85, the ground terminal 83, the spring 77, terminal 103 in the ECU 25, the ground wiring of the circuit board 91, terminal 108, and the connector 28. The second noise is then discharged from the external device 14 to the vehicle body of the vehicle 1.

[0092] As described above, multiple noises with different frequencies flow to the external device 14 via the coupling circuit 85, ground terminal 83, ECU 25, and connector 28. In this embodiment, these multiple noises include a first noise generated by the pressure sensor 74 and a second noise generated by the electric motor 22.

[0093] Note that the noise path is not limited to the examples above. For example, noise may flow to the vehicle body of vehicle 1 through terminal 104 of ECU 25, ground pin 26, screw 131, and housing 21. Alternatively, a second noise may flow from housing 21 to external device 14 via screw 131, ground pin 26, terminal 104 of ECU 25, ground wiring of circuit board 91, terminal 108, and connector 28.

[0094] In the brake system 10 according to the first embodiment described above, multiple noises with different frequencies flow to the external device 14 via the coupling circuit 85, ground terminal 83, ECU 25, and connector 28. The coupling circuit 85 has capacitors 87 and 88, which can remove noise according to the frequency characteristics of the capacitors 87 and 88. Multiple noises are discharged from one ground terminal 83 of the pressure sensor 74 to the external device 14 via the ECU 25 and connector 28. In other words, the ECU 25 can remove multiple noises if it has one terminal 103 that is electrically connected to the ground terminal 83. For example, a conventional pressure sensor also has one ground terminal, and a conventional ECU may also have one terminal that is electrically connected to that ground terminal. Therefore, the number of terminals in the ECU 25 does not need to increase from the conventional number. Accordingly, compared to the case where multiple terminals that carry different noises are provided in the ECU 25, the brake system 10 can reduce the number of terminals in the ECU 25 and improve the design flexibility of the ECU 25. Furthermore, the brake system 10 can reduce the number of parts because it can reduce the number of terminals on the ECU 25.

[0095] The coupling circuit 85 has multiple capacitors 87 and 88. That is, the coupling circuit 85 can remove multiple noises according to the respective frequency characteristics of the multiple capacitors 87 and 88. The multiple capacitors 87 and 88 are provided in the pressure sensor 74. As a result, compared to the case where capacitor 87 or capacitor 88 is provided in the ECU 25, the brake system 10 can reduce the number of electronic components mounted in the ECU 25 and improve the design flexibility of the ECU 25.

[0096] The multiple noises include a first noise generated by the pressure sensor 74 and a second noise generated by the electric motor 22. That is, the grounding terminal 83 of the pressure sensor 74 can allow not only the noise generated by the pressure sensor 74 but also the noise generated by the electric motor 22 to be sent to the external device 14 via the ECU 25 and connector 28. Therefore, the brake system 10 can reduce the number of parts compared to a system that further includes other parts to dissipate noise from the electric motor 22. Also, since the frequencies (in kHz) of the noise generated by the electric motor 22 and the frequencies (in MHz) of the noise generated by the pressure sensor 74 are significantly different from each other, the brake system 10 can suppress the mutual influence of these multiple frequencies.

[0097] The housing 21 is a conductive material, and the grounding terminal 83 is electrically connected to the housing 21 via a capacitor 88. Therefore, noise generated from, for example, the electric motor 22 is input to the capacitor 88 through the conductive housing 21. The capacitor 88 can remove this noise generated from the electric motor 22. Consequently, the brake system 10 can reduce the number of parts compared to a system that includes other components to dissipate noise from the housing 21.

[0098] The brake system 10 further comprises a screw 131, a gasket 133, and a grounding pin 26. The screw 131 has a screw shaft 135 and a screw head 136 provided at one end of the screw shaft 135. The gasket 133 seals the gap between the housing 21 and the case 27. The grounding pin 26 is attached to the ECU 25. A through hole 37 is provided in the housing 21. The screw shaft 135 passes through the through hole 37 and is coupled to the case 27. The screw head 136 contacts the housing 21. The grounding pin 26 elastically deforms inside the case 27 and contacts the screw shaft 135. Thus, the brake system 10 can dissipate noise from the ECU 25 to the housing 21 through the grounding pin 26 and the screw 131. The screw shaft 135 abuts against the grounding pin 26 so that the grounding pin 26 is elastically deformed. Therefore, even if there are variations in the dimensions and positions of the screws 131 and the grounding pins 26, the brake system 10 can more reliably electrically connect the screws 131 and the grounding pins 26. In addition, the screws 131 are coupled to the case 27 such that a portion of the screw shaft 135 is located inside the case 27. Therefore, the brake system 10 can prevent liquids and dust from entering the inside of the case 27 through the through hole 37, for example, with a single waterproof washer 132. Also, although the screws 131 contact the grounding pins 26, they are not fixed to the grounding pins 26. Therefore, the brake system 10 can be easily removed from the housing 21.

[0099] (Second embodiment) A second embodiment will be described below with reference to Figure 4. In the following descriptions of multiple embodiments, components having the same function as those already described will be denoted by the same reference numerals as those previously described, and their descriptions may be omitted. Furthermore, multiple components denoted by the same reference numerals do not necessarily share all functions and properties, and may have different functions and properties depending on the embodiment.

[0100] Figure 4 is a schematic circuit diagram showing a part of the hydraulic control device 11 according to the second embodiment. As shown in Figure 4, the pressure sensor 74 of the second embodiment has a variable capacitor 201 instead of a capacitor 88. The variable capacitor 201 is substantially equivalent to the capacitor 88, except as described below. In addition, the pressure sensor 74 of the second embodiment may further have a variable capacitor 201 in addition to capacitors 87 and 88.

[0101] The ECU25 controls the capacitance of the variable capacitor 201. A change in the capacitance of the variable capacitor 201 alters its frequency characteristics. Therefore, the ECU25 can change the resonant frequency of the variable capacitor 201.

[0102] In the brake system 10 of the second embodiment described above, at least one capacitor of the pressure sensor 74 includes a variable capacitor 201. Therefore, the brake system 10 can remove various noises by changing the frequency characteristics of the variable capacitor 201.

[0103] (Third embodiment) A third embodiment will be described below with reference to Figure 5. Figure 5 is a schematic cross-sectional view of the hydraulic control device 11 according to the third embodiment. As shown in Figure 5, the housing 21 of the third embodiment is provided with a plurality of through holes 301 instead of the through hole 37.

[0104] Each of the multiple through-holes 301 penetrates the housing 21 so as to open on the front 21a and rear 21b. The multiple through-holes 301 are arranged around the axis Ax around the mounting hole 31. The multiple through-holes 301 are surrounded by the gasket 45.

[0105] Case 27 of the third embodiment has multiple nuts 311 instead of nut 122. The multiple nuts 311 are formed integrally with the base 121, for example by insert molding. Note that the nuts 311 may be different parts from the base 121.

[0106] The hydraulic control device 11 of the third embodiment has a plurality of screws 321 instead of the screw 131. The screws 321 are made of metal and are conductive members. Each of the plurality of screws 321 has a screw shaft 325 and a screw head 326.

[0107] The screw shaft 325 passes through the through hole 301 in the housing 21 and fits into the nut 311. The screw head 326 is provided at the end of the screw shaft 325 in the -Y direction and abuts against the front surface 21a of the housing 21. In this way, the screw 321 attaches the base 121 of the case 27 to the back surface 21b of the housing 21.

[0108] The screw head 326 is located between the housing 21 and the motor case 41. The gasket 45 surrounds the screw head 326 and seals the gap between the housing 21 and the motor case 41 in a liquid-tight manner. As a result, the gasket 45 prevents liquid and dust from entering the inside of the case 27 through the through hole 301.

[0109] The screw shaft 325 passes through the nut 311 and is partially housed inside the case 27. At least one of the screw shafts 325 of the multiple screws 321 abuts against the leaf spring 112 of the grounding pin 26. This electrically connects the housing 21 to the grounding pin 26 via the screws 321.

[0110] The leaf spring 112 elastically deforms and contacts the screw 321. Therefore, even if there are variations in the dimensions of the screw 321 or the position of the grounding pin 26, the leaf spring 112 can reliably contact the screw shaft 325.

[0111] In the brake system 10 of the third embodiment described above, the electric motor 22 has a motor case 41 and a gasket 45. The motor case 41 is attached to the housing 21. The gasket 45 seals the gap between the housing 21 and the motor case 41. The screw head 326 is located between the housing 21 and the motor case 41 and is surrounded by the gasket 45. As a result, the brake system 10 can prevent liquids and dust from entering the inside of the case 27 through the through hole 301.

[0112] A braking device according to at least one embodiment described above, for example, comprises a wheel cylinder, a pressure source configured to pressurize the brake fluid in the wheel cylinder, an electric motor configured to drive the pressure source, a pressure sensor having a signal terminal configured to detect the fluid pressure in the brake fluid path between the wheel cylinder and the pressure source and outputting an electrical signal corresponding to the fluid pressure, a coupling circuit, and a ground terminal electrically connected to the coupling circuit, a housing supporting the pressure source and the electric motor, an electronic control unit controlling the pressure source and electrically connected to the signal terminal and the ground terminal, a case mounted on the housing and housing the electronic control unit, and a connector electrically connected to the electronic control unit and configured to connect to an external device, wherein the coupling circuit has at least one capacitor, and multiple noises with different frequencies flow to the external device via the coupling circuit, the ground terminal, the electronic control unit, and the connector. Therefore, for example, by having at least one capacitor in the coupling circuit, noise corresponding to the frequency characteristics of the capacitor can be removed. Multiple noises are discharged from a single ground terminal of the pressure sensor to an external device via the electronic control unit and connector. In other words, the electronic control unit can eliminate multiple noises if it has only one terminal electrically connected to the ground terminal. For example, a conventional pressure sensor also has one ground terminal, and a conventional electronic control unit may also have one terminal electrically connected to that ground terminal. Therefore, the number of terminals in the electronic control unit does not need to increase from the conventional number. Consequently, compared to a case where the electronic control unit is provided with multiple terminals that carry different types of noise, the braking device can reduce the number of terminals in the electronic control unit, thereby improving the design freedom (flexibility) of the electronic control unit.

[0113] In the braking device described above, for example, the coupling circuit has multiple capacitors. Therefore, for example, the coupling circuit can remove multiple noises corresponding to the frequency characteristics of each of the multiple capacitors. The multiple capacitors are provided in the pressure sensor. As a result, compared to the case where the capacitors are provided in the electronic control unit, the braking device can reduce the number of electronic components mounted in the electronic control unit, and the design flexibility of the electronic control unit can be improved.

[0114] In the above-described braking device, for example, at least one of the capacitors includes a variable capacitor. Therefore, for example, the braking device can remove various types of noise by changing the frequency characteristics of the variable capacitor.

[0115] In the above-described braking device, for example, the multiple noises include noise generated from the electric motor and noise generated from the pressure sensor. Therefore, for example, the grounding terminal of the pressure sensor can allow not only the noise generated by the pressure sensor but also the noise generated from the electric motor to be sent to an external device via the electronic control unit and connector. Consequently, the braking device can reduce the number of parts compared to a system that includes additional components to dissipate noise from the electric motor. Furthermore, since the frequencies of the noise generated from the electric motor and the noise generated from the pressure sensor are significantly different, the braking device can suppress the mutual influence of these multiple frequencies.

[0116] In the above-described braking device, for example, the housing is conductive, and the grounding terminal is electrically connected to the housing via at least one capacitor. Therefore, for example, noise generated from an electric motor is input to the capacitor through the conductive housing. The capacitor can remove the noise generated from the electric motor. Consequently, the braking device can reduce the number of parts compared to a device that further includes other components to dissipate noise from the housing.

[0117] Although embodiments of the present invention have been illustrated above, these embodiments and modifications are merely examples and are not intended to limit the scope of the invention. The above embodiments and modifications can be implemented in various other forms, and various omissions, substitutions, combinations, and changes can be made without departing from the spirit of the invention. Furthermore, the configurations and shapes of each embodiment and modification can be partially replaced. [Explanation of Symbols]

[0118] 10...Brake system (braking device), 12...Wheel cylinder, 14...External device, 21...Housing, 22...Electric motor, 23...Electric cylinder (pressure source), 25...Electronic control unit (ECU), 27...Case, 28...Connector, 74...Pressure sensor, 82...Signal terminal, 83...Ground terminal, 85...Coupling circuit, 87,88...Capacitor, 201...Variable capacitor.

Claims

1. Wheel cylinder and A pressure source configured to pressurize the brake fluid in the wheel cylinder, An electric motor configured to drive the pressure source, A pressure sensor comprising: a signal terminal configured to detect the fluid pressure in the brake fluid path between the wheel cylinder and the pressure source, and having a coupling circuit and a ground terminal electrically connected to the coupling circuit, wherein the signal terminal outputs an electrical signal corresponding to the fluid pressure, A housing that supports the pressure source and the electric motor, An electronic control unit that controls the pressure source and is electrically connected to the signal terminal and the ground terminal, A case that is attached to the housing and houses the electronic control unit, A connector, which is electrically connected to the aforementioned electronic control unit and configured to connect to an external device, It is equipped with, The coupling circuit has at least one capacitor, Multiple noises with different frequencies flow to the external device via the coupling circuit, the grounding terminal, the electronic control unit, and the connector. Braking device.

2. The coupling circuit has a plurality of capacitors, Braking device according to claim 1.

3. The at least one capacitor includes a variable capacitor. Braking device according to claim 1.

4. The aforementioned plurality of noises include noise generated from the electric motor and noise generated by the pressure sensor. Braking device according to claim 1.

5. The housing is conductive, The grounding terminal is electrically connected to the housing via the at least one capacitor. Braking device according to claim 1.

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