Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
  • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
  • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
  • B60T8/4068—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system the additional fluid circuit comprising means for attenuating pressure pulsations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
  • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
  • B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
  • B60T13/14—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using accumulators or reservoirs fed by pumps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
  • B60Y2400/00—Special features of vehicle units
  • B60Y2400/81—Braking systems

Definitions

• the present invention relates to a damping device, a hydraulic control unit, and a brake system.
• a hydraulic control unit is provided to control the braking force applied to the wheels.
• a plurality of valves and a pump are provided in the flow path within the hydraulic control unit.
• the opening and closing states of each valve are set to specific states, and the pump is driven.
• a reciprocating plunger pump is mainly used as the pump. Therefore, the pump pressurizes the brake fluid intermittently. Therefore, when the pump is driven, pressure pulsation occurs, which is a phenomenon in which the hydraulic pressure of the brake fluid pulsates in the flow path in the hydraulic control unit. The sound generated by such pressure pulsation may be perceived as noise by the vehicle occupants, and may be a factor that reduces comfort. Therefore, from the viewpoint of improving comfort, it is desirable to appropriately damp the pressure pulsation of the hydraulic control unit.
• the present invention aims to provide a damping device capable of damping pressure pulsations of a hydraulic control unit, a hydraulic control unit, and a brake system.
• a damping device in a hydraulic control unit that controls a braking force generated on a wheel, and has an inlet port connected to a discharge side of a pump and an outlet port that communicates with the inlet port, and damps pressure pulsation, the damping device comprising: a first fluid chamber that communicates with the inlet port via a first opening; a second fluid chamber that communicates with the first fluid chamber via a communication hole and communicates with the outlet port via a second opening; a first piston slidably provided in the first fluid chamber; a first biasing member that biases the first piston towards the first opening side; a valve body that is provided in the second fluid chamber and is capable of opening and closing the second opening side of the communication hole; and a second biasing member that biases the valve body towards the first opening side. and a protrusion capable of contacting the valve body.
• the hydraulic control unit is equipped with the above damping device.
• the brake system is equipped with the above hydraulic control unit.
• FIG. 1 is a schematic diagram showing a schematic configuration of a brake system according to a first embodiment of the present invention.
• Figure 2 A cross-sectional view showing the schematic configuration of the damping device related to the first embodiment of the present invention.
• Figure 3 A figure showing a state in which the first piston has moved to the right compared to the state in Figure 2 in the damping device according to the first embodiment of the present invention.
• Figure 4 A figure showing a state in which the first piston has moved to the right compared to the state in Figure 3 in the damping device according to the first embodiment of the present invention.
• FIG. 5I A cross-sectional view showing the schematic configuration of a damping device relating to the second embodiment of the present invention.
• Figure 6 A figure showing a state in which the second piston has moved to the right compared to the state in Figure 5 in the damping device according to the second embodiment of the present invention.
• Figure 7 A figure showing a state in which the first piston has moved to the right compared to the state in Figure 6 in the damping device according to the second embodiment of the present invention.
• FIG. 8 is a diagram showing a state in which the first piston has moved to the right compared to the state in FIG. 7 in the damping device according to the second embodiment of the present invention.
• a vehicle having four wheels 17 will be described as an example of a vehicle.
• the vehicle to which the present invention is applied is not limited to a vehicle having four wheels 17.
• the vehicle may be a vehicle having one, two, or three wheels 17, or a vehicle having five or more wheels 17.
• Fig. 1 is a schematic diagram showing the general configuration of a brake system 1.
• the brake system 1 is installed in a vehicle and is a system for controlling the braking force generated in the vehicle.
• the brake system 1 includes a brake pedal 11, a brake multiplier 12, a master cylinder 13, a reservoir 14, a hydraulic control unit 15, a brake device 16, and wheels 17.
• Brake system 1 is mounted on a vehicle having four wheels 17, and each wheel 17 is braked by a brake device 16 provided on each wheel 17.
• the braking force generated on each wheel 17 is controlled by a hydraulic control unit 15.
• FIG. 1 shows only a portion of brake system 1 related to one of the front wheels and the rear wheels, and does not show a portion related to the other of the front wheels and the rear wheels.
• the number of wheels 17 whose braking force is controlled by the hydraulic control unit according to the present invention may be other than four.
• the number of wheels 17 whose braking force is controlled by the hydraulic control unit 15 may be two.
• the brake system 15 may be installed in a vehicle having two wheels 17.
• the brake pedal 11 is used by the driver to apply the brakes. When applying the brakes, the driver depresses the brake pedal 11.
• the booster 12 is connected to the brake pedal 11 and amplifies the force applied to the brake pedal 11.
• the master cylinder 13 is connected to the booster 12 and incorporates a piston that reciprocates in conjunction with the brake pedal 11, generating hydraulic pressure according to the amount of braking operation.
• the reservoir 14 is attached to the master cylinder 13 and stores brake fluid.
• the hydraulic control unit 15 has a base 15a in which a flow path for brake fluid is formed.
• the master cylinder 13 and each brake device 16 are connected to the base 15a of the hydraulic control unit 15.
• the flow path for brake fluid in the base 15a of the hydraulic control unit 15 is connected to the wheel cylinder of the brake device 16.
• a braking force corresponding to the hydraulic pressure of the brake fluid in the wheel cylinder of the brake device 16 is generated in the wheel 1?.
• a main flow path 21, a sub-flow path 22, and a supply flow path 23 are formed in a base body 15a of a hydraulic control unit 15 as flow paths for brake fluid.
• the main flow path 21 circulates brake fluid in a master cylinder 13 to a wheel cylinder of a braking device 16.
• the sub-flow path 22 releases brake fluid in the wheel cylinder of the braking device 16.
• the supply flow path 23 supplies brake fluid from the master cylinder 13 to the sub-flow path 22.
• the base 15a of the hydraulic control unit 15 is provided with an inlet valve (EV) 31, a release valve (AV) 32, a first valve (USV) 33, a second valve (HSV) 34, an accumulator 35, a pump 36, and a motor 37 as components for controlling the braking force generated on each wheel 17.
• EV inlet valve
• AV release valve
• HSV second valve
• accumulator 35 accumulator
• pump 36 pump
• motor 37 motor 37
• a hydraulic control unit according to the present invention may be different from the configuration of hydraulic control unit 15 shown in Fig. 1 as long as it has pump 36.
• a hydraulic control unit according to the present invention also includes a hydraulic control unit obtained by omitting supply flow path 23, first valve 33, and second valve 34 from hydraulic control unit 15 shown in Fig. 1.
• the main flow path 21 communicates between the master cylinder 13 and the wheel cylinder of the braking device 16.
• the main flow path 21 includes a first main flow path 21a and two second main flow paths 21b.
• the first main flow path 21a is connected to the master cylinder 13.
• the two second main flow paths 21 branch off from the first main flow path 21a and are connected to each braking device 16.
• a first valve 33 is provided in the first main flow path 21a.
• An inlet valve 31 is provided in the second main flow path 21b.
• the sub-path 22 communicates between the brake device 16 side of the main path 21 via the inlet valve 31, the master cylinder 13 side of the main path 21 via the inlet valve 31, and the brake device 16 side via the first valve 33.
• the sub-path 22 includes two first sub-paths 22a and a second sub-path 22b. Each of the first sub-paths 22a is connected to the brake device 16 side of the main path 21 via the inlet valve 31.
• the second sub-path 22b connects the joining point of the two first sub-paths 22a to the master cylinder 13 side of the main path 21 via the inlet valve 31 and to the brake device 16 side of the first valve 33.
• a release valve 32 is provided in the first sub-path 22a.
• An accumulator 35 and a pump 36 are provided in the second sub-path 22b, in this order from the first sub-path 22a side.
• Pump 36 is driven by motor 37, and sucks brake fluid from first sub-path 22a and discharges it to main path 21.
• Pump 36 is a reciprocating plunger pump. Specifically, the plunger of pump 36 reciprocates as it is intermittently pressed by an eccentric cam provided on the output shaft of motor 37. This causes pump 36 to pump out brake fluid.
• the supply flow path 23 communicates between the master cylinder 13 side of the main flow path 21 and the suction side of the pump 36 in the sub-flow path 22 via the first valve 33.
• a second valve 34 is provided in the supply flow path 23.
• the inlet valve 31 is, for example, a solenoid valve that is opened in a non-energized state and closed in an energized state.
• the release valve 32 is, for example, a solenoid valve that is closed in a non-energized state and opened in an energized state.
• the first valve 33 is, for example, a solenoid valve that is opened in a non-energized state and closed in an energized state.
• the second valve 34 is, for example, a solenoid valve that is closed in a non-energized state and opened in an energized state.
• the inlet valve 31 is opened, the release valve 32 is closed, the first valve 33 is opened, and the second valve 34 is closed.
• the brake fluid flows from the master cylinder 13 to the wheel cylinder of the brake device 16 only through the main flow path 21, without passing through the sub-flow path 22 and the supply flow path 23.
• the piston of the master cylinder 13 is pressed, increasing the hydraulic pressure of the brake fluid in the wheel cylinder, and applying a braking force to the wheel 17.
• the antilock brake control is a control for preventing the wheels 17 from locking.
• the inlet valve 31 is closed, the release valve 32 is opened, the first valve 33 is opened, and the second valve 34 is closed.
• the brake fluid that has flowed into the accumulator 35 is returned to the main flow path 21 via the sub-flow path 22 by driving the pump 36.
• both inlet valve 31 and release valve 32 are closed, stopping the flow of brake fluid between main flow path 21 and sub flow path 22 and the wheel cylinder, maintaining the hydraulic pressure of the brake fluid in the wheel cylinder and maintaining the braking force applied to the wheel 17. Thereafter, inlet valve 31 is opened and release valve 32 is closed, restarting the flow of brake fluid between main flow path 21 and the wheel cylinder, increasing the hydraulic pressure of the brake fluid in the wheel cylinder, and increasing the braking force applied to the wheel 17.
• Anti-skid control is a control for stabilizing the behavior of a vehicle.
• the driving force and braking force of the vehicle are appropriately controlled.
• the inlet valve 31 is opened, the release valve 32 is closed, the first valve 33 is closed, and the second valve 34 is opened.
• the brake fluid flows from the master cylinder 13 to the wheel cylinder of the brake device 16 through the supply flow path 23 and the sub-flow path 22.
• the pump 36 is driven to increase the hydraulic pressure of the brake fluid in the wheel cylinder, and a braking force that brakes the wheel 17 is generated.
• the hydraulic control unit 15 controls the driving of the pump 36.
• pressure pulsation occurs, which is a phenomenon in which the hydraulic pressure of the brake fluid pulsates in the flow path in the hydraulic control unit 15.
• the sound generated by such pressure pulsation may be perceived as noise by the vehicle occupants, which may cause a decrease in comfort. Therefore, the hydraulic control unit 15 is provided with a damping device 100 that damps the pressure pulsation.
• the first fluid chamber S! is defined by the inner circumferential surface of the second hole portion 101b of the third cover 113. That is, the third cover 113 covers the first fluid chamber S! from the left side, and the first cover 111 covers the first fluid chamber S! from the right side. In other words, the left surface of the first cover 111 forms the right wall surface of the first fluid chamber S1.
• the first fluid chamber S1 has a substantially cylindrical shape.
• the first fluid chamber S1 communicates with the inlet port p1 via the first opening PO1.
• a second liquid chamber S2 is defined by the inner circumferential surface of the first cover 111.
• the left end of the inner circumferential surface of the first cover 111 is tapered radially inward.
• a communication hole 111a is formed in the center of the left end of the first cover 111.
• the second liquid chamber S2 communicates with the first liquid chamber S! via the communication hole 111a.
• a second cover 112 is fitted to the right end portion of the inner circumferential surface of the first cover 111.
• the second force bar 112 is formed in a generally circular plate shape having a second opening PO2 at its center.
• the second opening PO2 is connected to the outlet port P2.
• the second opening PO2 is arranged coaxially with the central axis of the housing 101. However, the second opening PO2 does not have to be arranged coaxially with the central axis of the housing 101.
• the right end of the outer circumferential surface of the second cover 112 expands in diameter radially outward.
• the right end of the inner circumferential surface of the first cover 111 also expands in diameter.
• the portion of the outer circumferential surface of the second cover 112 that expands in diameter radially outward is fitted into the portion of the inner circumferential surface of the first cover 111 that expands in diameter.
• the second liquid chamber S2 is defined by the left surface of the second cover 112.
• the second cover 112 covers the second liquid chamber S2 from the right side.
• the left surface of the second cover 112 forms the right wall surface of the second liquid chamber S2.
• the second liquid chamber S2 communicates with the outlet port P2 via the second opening PO2.
• the first piston 121 is housed in the second hole portion 101b.
• the first piston 121 has a substantially cylindrical shape.
• the first piston 121 is disposed coaxially with the central axis of the second hole portion 101b.
• the first piston 121 has a first cylindrical portion 121a, a second cylindrical portion 121b, and a protrusion portion 121c.
• the first cylindrical portion 121a, the second cylindrical portion 121b, and the protrusion portion 121c have a cylindrical shape and are disposed coaxially with each other.
• the first cylindrical portion 121a, the second cylindrical portion 121b, and the protrusion 121c are continuous in this order from the left side.
• the outer diameters of the first cylindrical portion 121a, the second cylindrical portion 121b, and the protrusion 121c decrease in this order.
• the outer peripheral surface of the first cylindrical portion 121a is slidable against the inner peripheral surface of the second hole portion 121b. Therefore, the first piston 121 is provided axially slidable in the first fluid chamber S1.
• An annular groove 121d is formed in the outer circumferential surface of the first cylindrical portion 121a.
• the annular groove 121d extends in the circumferential direction of the first piston 121.
• a first seal member 131 is fitted into the annular groove 121d.
• the first seal member 131 is, for example, a circular ring.
• the first seal member 131 is pressed against the inner circumferential surface of the second hole portion 101b. This causes a gap between the outer circumferential surface of the first cylindrical portion 121a and the inner circumferential surface of the second hole portion 101b to be liquid-tightly sealed.
• the first piston 121 is urged leftward by a first urging member 141.
• the first urging member 141 is, for example, an elastic member such as a spring.
• the first urging member 141 is disposed between the first piston 121 and the first cover 111.
• One end (the left end in FIG. 2) of the first urging member 141 abuts against an abutment surface 121e provided on the right side of the first piston 121.
• the abutment surface 121e is the right surface of the first cylindrical portion 121a (that is, the step surface between the first cylindrical portion 121a and the second cylindrical portion 121b).
• the other end (the right end in FIG.
• First urging portion Material 141 is in a shrunken state relative to its natural length.
• a plurality of first through holes 121f are formed in the first piston 121.
• the first through holes 121f penetrate the first piston 121 from the left side to the right side.
• the first through holes 121f extend from the left side surface of the first cylindrical portion 121a to the right side surface of the second cylindrical portion 121b.
• the inner diameter of the first through holes 121f is, for example, about 0.4 mm to 0.5 mm in diameter.
• the first through holes 121f extend in the axial direction.
• the path of the first through hole 121f is not particularly limited.
• the first through hole 121f may extend in a direction inclined with respect to the axial direction, or may be curved or bent.
• the first through holes 121f are arranged at equal intervals in the circumferential direction of the first piston 121.
• the arrangement of the first through holes 121f is not limited to this example.
• the first through holes 121f may be arranged at unequal intervals in the circumferential direction.
• the number of the first through holes 121f may be one.
• the brake fluid can flow from the left side to the right side of the first piston 121 through the first through hole 121f.
• the first through hole 121f is provided to enhance the effect of reducing pressure pulsation. The function of the first through hole 121f will be described later.
• the first cover 111 also has a plurality of second through holes 111c that have the same effect as the first through holes 121f.
• the second through holes 111c penetrate the first cover 111 from the left side to the right side.
• the second through holes 111e extend from a radially inner side of a contact point of the recessed portion 111b with the first biasing member 141 to a right side surface of the first cover 111.
• the inner diameter of the second through holes 111c is, for example, about 0.4 mm to 0.5 mm in diameter.
• the second through holes 111e extend in the axial direction.
• the path of the second through hole 111 c is not particularly limited.
• the second through hole 111 e may extend in a direction inclined with respect to the axial direction, or may be curved or bent.
• the second through holes 111e are arranged at equal intervals in the circumferential direction of the first cover 111.
• the arrangement of the second through holes 111c is not limited to this example.
• the second through holes 111c may be arranged at unequal intervals in the circumferential direction.
• the number of second through holes 111c may be one.
• the brake fluid can flow from the left side to the right side of the first cover 111 through the second through hole 111e.
• the second through hole 111c is provided to enhance the effect of reducing pressure pulsation. The function of the second through hole 111c will be described later.
• the valve element 151 is provided in the second fluid chamber S2 and can open and close the right side of the communication hole 111a.
• brake fluid can flow through the communication hole 111a.
• This state corresponds to the open state of the valve element 151 and the open state of the communication hole 111a.
• brake fluid cannot flow through the communication hole 111a.
• This state corresponds to the closed state of the valve element 151 and the closed state of the communication hole 111a.
• the valve body 151 has, for example, a spherical shape. However, the shape of the valve body 151 may be a shape other than a spherical shape.
• the second biasing member 142 is, for example, an elastic member such as a spring.
• the second biasing member 142 is disposed between the second cover 112 and the valve body 151.
• the second biasing member 142 expands and contracts in the left-right direction.
• the second biasing member 142 is in a contracted state relative to its natural length. Therefore, the valve body 151 is biased to the left by the second biasing member 142.
• the valve body 151 is opened and closed by a protrusion 121c of the first piston 121. P1.
• the first opening PO1 is disposed coaxially with the central axis of the housing 201. However, the first opening PO1 does not have to be disposed coaxially with the central axis of the housing 201.
• the first cover 211 is fitted into the third hole 201c.
• the first cover 211 has a substantially cylindrical shape.
• the first cover 211 has a first cylindrical portion 211a and a second cylindrical portion 211b.
• the first cylindrical portion 211a and the second cylindrical portion 211b have a cylindrical shape and are arranged coaxially with each other.
• the first cylindrical portion 211a and the second cylindrical portion 211b are continuous in this order from the right side.
• the outer diameter of the second cylindrical portion 211b is smaller than the outer diameter of the first cylindrical portion 211a.
• the inner diameter of the first cylindrical portion 211a and the inner diameter of the second cylindrical portion 211b are the same.
• the inner diameter of the second cylindrical portion 211b may be smaller or larger than the inner diameter of the first cylindrical portion 211a.
• the first cylindrical portion 211a is fitted into the third hole portion 201c.
• the outer peripheral surface of the second cylindrical portion 211b is spaced apart in the radial direction from the inner peripheral surface of the second hole portion 201b.
• a first liquid chamber S1 is defined by the right surface of the third cover 213, the left surface of the first cover 211, the inner circumferential surface of the first hole 201 of the housing 201, and the inner circumferential surface of the second hole 201 of the housing 201.
• the third cover 213 covers the first liquid chamber S1 from the left side.
• the first cover 211 covers the first liquid chamber S1 from the right side.
• the left surface of the first cover 211 forms the right wall surface of the first liquid chamber S1.
• the first liquid chamber S1 has a substantially cylindrical shape.
• the first liquid chamber S1 communicates with the inlet port P1 via the first opening PO1.
• a second liquid chamber S2 is defined by the inner circumferential surface of the first cover 211.
• the left end portion of the inner circumferential surface of the first cover 211 narrows radially inward.
• a communication hole 211c is formed in the center of the left end portion of the first cover 211.
• the second liquid chamber S2 communicates with the first liquid chamber S! via the communication hole 211e.
• a second cover 212 is fitted to the right end of the inner circumferential surface of the first cover 211.
• the second force bar 212 is formed in a generally circular plate shape having a second opening PO2.
• the second opening PO2 is connected to the outlet port P2.
• the second opening PO2 is disposed radially outward from the center of the second cover 212.
• the number of second openings PO2 may be one.
• the right end of the inner circumferential surface of the first cover 211 has an expanded diameter.
• the second cover 212 is fitted into the expanded diameter portion of the inner circumferential surface of the first cover 211.
• the second liquid chamber S2 is defined by the left face of the second cover 212.
• the second cover 212 covers the second liquid chamber S2 from the right side.
• the left face of the second cover 212 forms the right wall surface of the second liquid chamber S2.
• the second liquid chamber S2 communicates with the outlet port P2 via the second opening PO2.
• the first piston 221 is accommodated inside the first hole portion 201a and the second hole portion 201b.
• the first piston 221 has a substantially cylindrical shape.
• the first piston 221 is disposed coaxially with the central axes of the first hole portion 201a and the second hole portion 201b.
• the first piston 221 has a first cylindrical portion 221a, a second cylindrical portion 221b, and a protrusion 221c.
• the first cylindrical portion 221a, the second cylindrical portion 221b, and the protrusion 221c have a cylindrical shape and are disposed coaxially with each other.
• the first cylindrical portion 221a, the second cylindrical portion 221b, and the protrusion 221c are continuous in this order from the left side.
• the outer diameters of the first cylindrical portion 221a, the second cylindrical portion 221b, and the protrusion 221c decrease in this order.
• the outer peripheral surface of the first cylindrical portion 221a is slidable against the inner peripheral surface of the first hole portion 201a. Therefore, the first piston 221 is provided axially slidable in the first liquid chamber s!.
• An annular groove 221d is formed on the outer circumferential surface of the first cylindrical portion 221a.
• the annular groove 221d extends in the circumferential direction of the first piston 221.
• a first seal member 231 is fitted into the annular groove 221d.
• the first seal member 231 is, for example, a round ring.
• the first seal member 231 is pressed against the inner circumferential surface of the first hole portion 201a. This causes a gap between the outer circumferential surface of the first cylindrical portion 221a and the inner circumferential surface of the first hole portion 201a to be liquid-tightly sealed.
• the first piston 221 is urged leftward by the first urging member 241.
• the first urging member 241 is, for example, an elastic member such as a spring.
• the first urging member 241 is disposed between the first piston 221 and the first cover 211.
• One end (the left end in FIG. 5) of the first urging member 241 abuts against an abutment surface 221e provided on the right side of the first piston 221.
• the abutment surface 221e is the right surface of the second cylindrical portion 221b (that is, the step surface between the second cylindrical portion 221b and the protrusion 221c).
• the other end (the right end in FIG.
• the annular groove 211d is formed in the left end of the outer circumferential surface of the second cylindrical portion 211b of the first cover 211, and extends in the circumferential direction. Therefore, the other end of the first biasing member 241 abuts against the periphery on the left side of the communicating hole 211c.
• the first biasing member 24! expands and contracts in the left-right direction.
• the first biasing member 241 is in a contracted state relative to its natural length.
• a plurality of first through holes 221f are formed in the first piston 221.
• the first through holes 221f penetrate the first piston 221 from the left side to the right side.
• the first through holes 221f extend from the left side surface of the first cylindrical portion 221a to the right side surface of the first cylindrical portion 221a (that is, the step surface between the first cylindrical portion 221a and the second cylindrical portion 221b).
• the inner diameter of the first through holes 221f is, for example, about 0.4 mm to 0.5 mm in diameter.
• the first through holes 221f extend in the axial direction.
• the path of the first through hole 221f is not particularly limited.
• the first through hole 221f may extend in a direction inclined with respect to the axial direction, or may be curved or bent.
• the first through holes 221f are arranged at equal intervals in the circumferential direction of the first piston 221.
• the arrangement of the first through holes 221f is not limited to this example.
• the first through holes 221f may be arranged at unequal intervals in the circumferential direction.
• the number of the first through holes 221f may be one.
• the brake fluid can flow from the left side to the right side of the first piston 221 through the first through hole 221f.
• the first through hole 221f is provided to enhance the effect of reducing pressure pulsation. The function of the first through hole 221f will be described later.
• the brake fluid that has passed through the first through hole 221f is sent to a space outside the first biasing member 241 (specifically, a space on the radially outer side) in a space in the first fluid chamber S1 to the right of the first piston 221.
• a communication groove 221g is provided in the contact surface 221e of the first piston 221, which communicates the space inside the first biasing member 241 (specifically, a space on the radially inner side) with the space outside the first biasing member 241.
• the communication groove 221g extends in the radial direction of the first piston 221. Brake fluid can flow from the space outside the first biasing member 241 to the space inside the first biasing member 241 through the communication groove 221g.
• the number of communication grooves 221g may be one.
• the communication groove 221g is provided to appropriately send brake fluid to the communication hole 211c and the second fluid chamber S2. The function of the communication groove 221g will be described later.
• a hole 221h is formed in the first cylindrical portion 221a.
• the hole 221h is a portion of the first piston 221 that is recessed from the left side to the right side. In the example of FIG. 5, the hole 221h is recessed from the left side surface of the first cylindrical portion 221a to the right side.
• the hole 221h is disposed coaxially with the central axis of the housing 201. However, the hole 221h does not have to be disposed coaxially with the central axis of the housing 201.
• the second piston 222 is housed in the hole 221h.
• the second piston 222 has a substantially cylindrical shape.
• the second piston 222 is disposed coaxially with the central axis of the hole 221h.
• the outer peripheral surface of the second piston 222 is slidable against the inner peripheral surface of the hole 221h. Therefore, the second piston 222 is provided slidably in the axial direction in the hole 221h.
• An annular groove 222a is formed on the outer circumferential surface of the second piston 222.
• the annular groove 222a extends in the circumferential direction of the second piston 222.
• a second seal member 232 is fitted into the annular groove 222a.
• the second seal member 232 is, for example, an O ring.
• the second seal member 232 is pressed against the inner circumferential surface of the hole 221h. This forms a liquid-tight seal between the outer circumferential surface of the second piston 222 and the inner circumferential surface of the hole 221h.
• the second piston 222 is urged leftward by the third urging member 243.
• the third urging member 243 is, for example, an elastic member such as a spring.
• the third urging member 243 is disposed between the second piston 222 and a bottom surface of the hole 221h (the right-hand surface of the inner surface of the hole 221h in Fig. 5).
• One end (the left end in Fig. 5) of the third urging member 243 abuts against the recessed portion 222b of the second piston 222.
• the recessed portion 222b is provided in the center of the right-hand surface of the second piston 222.
• the other end (the right end in FIG. 5) of the third urging member 243 abuts against the bottom surface of the hole portion 221h.
• the third urging member 243 expands and contracts in the left-right direction.
• the third urging member 243 is in a contracted state relative to its natural length.
• the valve element 251 is provided in the second fluid chamber S2 and can open and close the right side of the communication hole 211c.
• brake fluid can flow through the communication hole 211e.
• This state corresponds to the open state of the valve element 251 and the open state of the communication hole 211c.
• brake fluid cannot flow through the communication hole 211c.
• This state corresponds to the closed state of the valve element 251 and the closed state of the communication hole 211e.
• the valve body 251 has a head 251a and a shaft portion 251.
• the head 251a has a substantially hemispherical shape.
• the left side of the head 251a is spherical and can open and close the communication hole 211c.
• the shaft portion 251b extends rightward from the right side surface of the head 251a.
• the cross-sectional shape of the shaft portion 251b is, for example, a circular or polygonal shape.
• the shaft portion 251b is disposed coaxially with the central axis of the housing 20!.
• the second biasing member 242 is, for example, an elastic member such as a spring.
• the second biasing member 242 is disposed between the second cover 212 and the valve body 251.
• the second biasing member 242 expands and contracts in the left-right direction.
• the second biasing member 242 is in a contracted state relative to its natural length. Therefore, the valve body 251 is biased to the left by the second biasing member 242.
• the valve element 251 is opened and closed by a protrusion 221e of the first piston 221.
• the protrusion 221e extends axially from the right surface of the second cylindrical portion 221b to the right. In this manner, the protrusion 221c is provided on the right side of the first piston 221.
• the protrusion 221c is inserted into the communication hole 211c, and the tip of the protrusion 221c can come into contact with the valve element 25i.
• the valve element 251 is opened. In this way, the protrusion 221e can be inserted into the communicating hole 211c and can abut against the valve body 251.
• the elastic member 261 is provided on the left side of the first cover 211, and has a ring shape extending in the circumferential direction of the first cover 211. In the example of FIG. 5, the elastic member 261 abuts against a left surface of the first cylindrical portion 211a of the first cover 211. In addition, the elastic member 261 is sandwiched between the outer peripheral surface of the second cylindrical portion 211b of the first cover 211 and the inner peripheral surface of the second hole portion 201b.
• the elastic member 261 is, for example, a ring.
• FIG. 5 above shows the damping device 200 in the hydraulic control unit 15 under normal conditions when the pump 36 is not driven.
• the first piston 221 is biased to the left by the first biasing member 241 and is located at the leftmost position in the movable range. Therefore, the protrusion 221c of the first piston 221 is separated from the valve body 251 and is not in contact with the valve body 251.
• the valve body 251 is biased to the left by the second biasing member 242 and is located at the leftmost position in the movable range. Therefore, the valve body 251 is in a closed state.
• the second piston 222 is biased to the left by the third biasing member 243 and is positioned at the leftmost position in the movable range.
• the pump 36 when antilock brake control or anti-skid control is executed, the pump 36 is driven.
• brake fluid flows into the damping device 200 through the first opening PO1, and the pressure in the space to the left of the first piston 221 in the first fluid chamber S1 increases.
• the second piston 222 moves to the right first.
• the elastic modulus is a physical property that indicates the resistance to deformation, and is also called the spring constant, elastic constant, or elastic coefficient.
• Fig. 6 is a diagram showing a state in which the second piston 222 in the damping device 200 has moved to the right compared to the state in Fig. 5.
• pressure is accumulated in the space to the left of the first piston 221 in the first liquid chamber S1.
• the second piston 222 is pressed to the right by the pressure in the space to the left of the first piston 221 in the first liquid chamber S1, and the second piston 222 moves to the right compared to the state in Fig. 5.
• the third biasing member 243 expands and contracts, and as a result, it contracts.
• the force acting on the second piston 222 is absorbed by the third biasing member 243.
• the third biasing member 243 expands and contracts in accordance with the movement of the second piston 222, thereby attenuating the pressure pulsation.
• Fig. 7 is a diagram showing a state in which the first piston 221 in the damping device 200 has moved to the right compared to the state in Fig. 6.
• pressure is stored in the space to the left of the first piston 221 in the first liquid chamber S1.
• the first piston 221 is pressed to the right by the pressure in the space to the left of the first piston 221 in the first liquid chamber S1, and the first piston 221 has moved to the right compared to the state in Fig. 6.
• the second piston 222 may or may not move relative to the first piston 221.
• the first biasing member 241 expands and contracts and eventually shrinks.
• the force acting on the first piston 221 is absorbed by the first biasing member 241.
• the first biasing member 241 expands and contracts in accordance with the movement of the first piston 221, thereby attenuating the pressure pulsation.
• Fig. 8 is a diagram showing a state in which the first piston 221 in the damping device 200 has moved to the right compared to the state in Fig. 7.
• the first piston 221 has moved further to the right compared to the state in Fig. 7.
• the protrusion 221c of the first piston 221 is in contact with the valve body 251.
• the valve body 251 has moved to the right compared to the state in Fig. 7.
• the valve body 251 is separated from the communication hole 211c. Therefore, the communication hole 211c is opened, and the brake fluid can flow through the communication hole 211c.
• the brake fluid passes through the communicating hole 21e and flows out from the second fluid chamber S2 through the second opening PO2.
• the first biasing member 241 may be completely contracted and the gap between the spring wires forming the first biasing member 241 may be blocked. Even in such a case, the brake fluid sent through the first through hole 221f to the space on the right side of the first piston 221 in the first fluid chamber S! can flow from the space outside the first biasing member 241 to the space inside the first biasing member 241 through the communication groove 221g. Therefore, the brake fluid can be sent from the space inside the first biasing member 241 to the communication hole 21e, so that the brake fluid can be appropriately discharged from the second fluid chamber S2 through the second opening PO2.
• valve element 251 when the valve element 251 is in the open state, the valve element 251 can abut against the second cover 212.
• the shaft portion 251b of the valve element 251 moves along the central axis of the housing 201.
• the second opening PO2 is disposed radially outward from the center of the second cover 212. Therefore, the tip of the shaft portion 251b of the valve element 251 can abut against the second cover 212.
• the valve element 25i does not vibrate, and the attitude of the valve element 251 is stabilized.
• the damping device 200 has a first fluid chamber S which communicates with an inlet port P1 via a first opening PO1.
• a second fluid chamber S2 communicating with the first fluid chamber S1 through a communication hole 211 and communicating with the outlet port P2 through a second opening PO2;
• a first piston 221 slidably provided in the first fluid chamber S1;
• a first biasing member 241 biasing the first piston 221 toward the first opening PO1;
• a second biasing member 242 biasing the valve body 251 toward the first opening PO1; and a protrusion 221c that can be inserted into the damping device 221c and can come into contact with the valve body 251.
• the damping device 200 includes a hole 221h recessed from the first opening PO1 side toward the second opening PO2 side in the first piston 221, a second piston 222 slidably provided in the hole 221h, and a third biasing member 243 biasing the second piston 222 toward the first opening PO1 side.
• the second piston 222 moves toward the second opening PO2 side.
• the third biasing member 243 expands and contracts in accordance with the movement of the second piston 222, thereby making it possible to further attenuate the pressure pulsation. Therefore, the pressure pulsation can be more effectively attenuated.
• the sliding direction of the second piston 222 is different from the sliding direction of the first piston 221.
• Valve body 200 Damping device 201 Housing 211 First cover 211c Communication hole 212 Second cover 213 Third cover 221 First piston 221c Projection 221e Contact surface 221f First through hole 221g Communication groove 221h Hole 222 Second piston 231 First seal member 232 Second seal member 241 First biasing member 242 Second biasing member 243 Third biasing member 251 Valve body 261 Elastic member P1 Inlet port

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Regulating Braking Force (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=88600575

Family Applications (1)

Country Status (5)

Cited By (1)

Citations (2)

Family Cites Families (5)

• 2023
  • 2023-09-26 KR KR1020257015784A patent/KR20250087684A/ko active Pending
  • 2023-09-26 CN CN202380073675.6A patent/CN120076966A/zh active Pending
  • 2023-09-26 JP JP2024550920A patent/JPWO2024084308A1/ja active Pending
  • 2023-09-26 DE DE112023004347.7T patent/DE112023004347T5/de active Pending
  • 2023-09-26 WO PCT/IB2023/059490 patent/WO2024084308A1/ja not_active Ceased

Patent Citations (2)

Also Published As

Similar Documents

Legal Events