JP2015182577A - Stroke simulator and brake system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stroke simulator capable of relaxing discomfortness at the time when braking is operated, with a base body being reduced in size.SOLUTION: A stroke simulator 2 includes a second bottomed cylinder hole 12 formed at a base body 100, a piston 21 inserted into the second cylinder hole 12, a lid member 24 for closing an opening part of the second cylinder hole 12, a second coil spring 23 arranged between the piston 21 and the lid member 24, and a disc spring 25(elastic member) provided at the lid member 24. The second coil spring 23 and the disc spring 25 are provided side by side along radial direction of the second cylinder hole 12, and the axial direction of the second cylinder hole 12, the disc spring 25 is formed smaller than the second coil spring 23.

Description

  The present invention relates to a stroke simulator and a vehicle brake system used in a vehicle brake system.

  A brake fluid pressure generating device for a vehicle brake system includes a master cylinder, a slave cylinder that uses a motor as a drive source, and a stroke simulator that applies an operational reaction force to a brake pedal.

  As a conventional stroke simulator, a bottomed cylinder hole formed in a base, a piston inserted into the cylinder hole, a lid member that closes an opening of the cylinder hole, and a piston and a lid member are arranged. There are some which have two coil springs (see, for example, Patent Document 1).

  In the conventional stroke simulator described above, two coil springs are connected in series in the axial direction of the cylinder hole. And the spring constant of the other coil spring is set larger than the spring constant of one coil spring, and the reaction force characteristic is switched according to the stroke amount of the brake pedal.

JP 2012-206711 A

  In the conventional stroke simulator described above, since the plurality of coil springs are connected in the axial direction of the cylinder hole, there is a problem that the cylinder hole becomes larger in the axial direction and the base becomes larger.

  It is an object of the present invention to provide a stroke simulator and a vehicular brake system that can solve the above-described problems, relieve the uncomfortable feeling during brake operation, and reduce the size of the base.

  In order to solve the above-mentioned problem, the present invention is a stroke simulator that applies an operation reaction force to a brake operator. The stroke simulator described above includes a bottomed cylinder hole formed in the base, a piston inserted into the cylinder hole, a lid member for closing the opening of the cylinder hole, and between the piston and the lid member. A coil spring disposed on the lid member, and an elastic member provided on the lid member. The coil spring and the elastic member are juxtaposed in the radial direction of the cylinder hole, and the elastic member is formed smaller than the coil spring in the axial direction of the cylinder hole.

  In the brake fluid pressure generating device, when the brake fluid pressure of the master cylinder is transmitted to the wheel cylinder, when the brake operation element reaches a predetermined operation amount, the operation reaction force against the increase amount of the operation amount of the brake operation element is reduced. There is a changing point where the amount of increase increases.

In the stroke simulator of the present invention, in the process of operating the brake operator, after the reaction force is applied to the brake operator by the coil spring, the piston comes into contact with the elastic member, and the brake operator and the elastic member An operational reaction force is applied to. That is, when the brake operation element reaches a predetermined operation amount, the increase amount of the operation reaction force with respect to the increase amount of the operation amount of the brake operation element increases.
Thus, in the stroke simulator of the present invention, the reaction force characteristic of the operation reaction force applied to the brake operator is approximated to the reaction force characteristic when the brake fluid pressure of the master cylinder is transmitted to the wheel cylinder. Can do.

  In the stroke simulator of the present invention, since the coil spring and the elastic member are arranged in the radial direction of the cylinder hole, the cylinder hole is made smaller in the axial direction than when a plurality of coil springs are connected in series. And the size of the substrate can be reduced.

  In addition, as said elastic member, disk shaped plate spring members, such as a disk spring and a wave washer, can be used, for example. Thus, by using various elastic members, the operation reaction force applied to the brake operator can be set to a desired reaction force characteristic. In particular, when the elastic member is a disc-shaped leaf spring member, the spring load can be output with a small stroke amount, and the axial length of the stroke simulator can be further reduced.

In the above-described stroke simulator, it is desirable that the spring constant of the elastic member is set larger than the spring constant of the coil spring.
In this configuration, when the brake operation element reaches a predetermined operation amount, the increase amount of the operation reaction force with respect to the increase amount of the stroke amount of the brake operation element can be clearly increased. Therefore, the reaction force characteristic of the operation reaction force applied to the brake operator can be approximated to the reaction force characteristic when the brake fluid pressure of the master cylinder is transmitted to the wheel cylinder.

  In the above-described stroke simulator, when the elastic member is disposed inside the coil spring, the cylinder hole can be prevented from becoming large in the radial direction.

Further, the vehicle brake system of the present invention includes a brake fluid pressure generating device that generates a brake fluid pressure according to the operation amount of the brake operator, and the above-described stroke simulator of the present invention. It is provided on the base body of the brake fluid pressure generator.
In such a vehicle brake system, the reaction force characteristic of the operation reaction force applied to the brake operator by the stroke simulator is approximated to the reaction force characteristic when the brake fluid pressure of the master cylinder is transmitted to the wheel cylinder. be able to.
In the stroke simulator, since the coil spring and the elastic member are arranged in the radial direction of the cylinder hole, the cylinder hole can be made smaller in the axial direction than when a plurality of coil springs are connected in series. The substrate can be reduced in size. Therefore, the vehicle brake system can be reduced in size.

In the stroke simulator and the vehicle brake system of the present invention, the reaction force characteristic of the operation reaction force applied to the brake operator is approximated to the reaction force characteristic when the brake fluid pressure of the master cylinder is transmitted to the wheel cylinder. It is possible to alleviate the uncomfortable feeling during brake operation.
Further, in the stroke simulator and the vehicle brake system of the present invention, the coil spring and the elastic member are arranged in parallel in the radial direction of the cylinder hole, so that the cylinder hole can be reduced in the axial direction and the base can be downsized. be able to.

It is the schematic diagram which showed the brake system for vehicles using the stroke simulator of this embodiment. It is the sectional side view which showed the initial state of the stroke simulator of this embodiment. In the stroke simulator of this embodiment, it is a sectional side view in the state where the piston contacted the bush. In the stroke simulator of this embodiment, it is a sectional side view in the state where the piston contacted the disc spring. It is the graph which showed the reaction force characteristic of the operation reaction force given to a brake pedal.

  Embodiments of a stroke simulator and a vehicle brake system according to the present invention will be described in detail with reference to the drawings as appropriate.

  As shown in FIG. 1, the vehicle brake system A includes a by-wire brake system that operates when a prime mover (such as an engine or an electric motor) is started, and a hydraulic system that operates when the prime mover is stopped. It is equipped with both brake systems.

  The vehicle brake system A can be mounted not only on a vehicle that uses only an engine (internal combustion engine) as a power source, but also on a hybrid vehicle that uses a motor together, an electric vehicle that uses only a motor as a power source, and a fuel cell vehicle. .

The vehicle brake system A includes a brake fluid pressure generator A1 that generates a brake fluid pressure according to the stroke amount (operation amount) of the brake pedal P (“brake operator” in the claims).
Further, the vehicle brake system A includes a slave cylinder A2 that generates a brake fluid pressure by driving a motor (electric actuator) according to an operation amount of the brake pedal P.
Furthermore, the vehicle brake system A includes a hydraulic pressure control device A3 that supports stabilization of vehicle behavior.
The brake fluid pressure generator A1, the slave cylinder A2, and the fluid pressure controller A3 are configured as separate units and communicate with each other via an external pipe.

  The brake fluid pressure generator A1 includes a base body 100, a master cylinder 1 that operates by operating the brake pedal P, a stroke simulator 2 that applies a pseudo operation reaction force to the brake pedal P, and an electronic control device 7. I have.

  The base body 100 is a metal part mounted on a vehicle, and has two cylinder holes 11 and 12 and a plurality of hydraulic pressure paths 9a to 9e. Various components such as the reservoir 3 are attached to the base body 100.

  The master cylinder 1 is a tandem piston type, and includes two pistons 1a and 1b and two coil springs 1c and 1d. The master cylinder 1 is provided in a bottomed cylindrical first cylinder hole 11.

  A first pressure chamber 1e is formed between the bottom surface of the first cylinder hole 11 and the secondary piston 1a. A first coil spring 1c is accommodated in the first pressure chamber 1e. The 1st coil spring 1c pushes back the secondary piston 1a which moved to the bottom face side to the opening part side.

  A second pressure chamber 1f is formed between the secondary piston 1a and the primary piston 1b. A second coil spring 1d is accommodated in the second pressure chamber 1f. The second coil spring 1d pushes the secondary piston 1a moved to the bottom side back to the opening side.

The rod P 1 of the brake pedal P is inserted into the first cylinder hole 11. The tip of the rod P1 is connected to the primary piston 1b. Thereby, the primary piston 1b is connected to the brake pedal P via the rod P1.
The secondary piston 1a and the primary piston 1b receive the depression force of the brake pedal P, slide in the first cylinder hole 11 toward the bottom surface side, and pressurize the brake fluid in both the pressure chambers 1e and 1f.

  The reservoir 3 is a container that stores brake fluid, and is attached to the upper surface of the base body 100. Both the pressure chambers 1e and 1f can be supplied with brake fluid from the reservoir 3 through the communication holes 3a and 3a.

  The stroke simulator 2 includes a piston 21, two coil springs 22 and 23, a lid member 24, and a disc spring 25 provided on the lid member 24. The stroke simulator 2 is provided in the bottomed cylindrical second cylinder hole 12. The opening of the second cylinder hole 12 is closed by a lid member 24.

  A pressure chamber 12 a in which the piston 21 is accommodated is formed in a portion of the second cylinder hole 12 on the bottom surface 12 d side. A storage chamber 12 b is formed between the piston 21 and the lid member 24. Two coil springs 22 and 23 and a disc spring 25 are accommodated in the accommodating chamber 12b. Both the coil springs 22 and 23 and the disc spring 25 push back the piston 21 moved to the lid member 24 side to the bottom surface 12d side and apply an operation reaction force to the brake pedal P.

Next, each hydraulic path formed in the base body 100 will be described.
The first main hydraulic pressure path 9 a is a hydraulic pressure path starting from the first pressure chamber 1 e of the first cylinder hole 11. The output port 15a that is the end point of the first main hydraulic pressure passage 9a is connected to a pipe Ha that reaches the hydraulic pressure control device A3.

  The second main hydraulic pressure path 9 b is a hydraulic pressure path starting from the second pressure chamber 1 f of the first cylinder hole 11. A pipe Hb leading to the hydraulic pressure control device A3 is connected to the output port 15b which is the end point of the second main hydraulic pressure path 9b.

  The communication hydraulic pressure paths 9c and 9d are hydraulic pressure paths from the input ports 15c and 15d to the main hydraulic pressure paths 9a and 9b. Pipes Hc and Hd reaching the slave cylinder A2 are connected to the input ports 15c and 15d.

  The branch hydraulic pressure path 9 e is a hydraulic pressure path that branches from the first main hydraulic pressure path 9 a and reaches the pressure chamber 12 a of the stroke simulator 2.

  In the first main hydraulic pressure path 9a, a first switching valve 4 for opening and closing the first main hydraulic pressure path 9a is provided on the downstream side (output port 15a side) of the connection portion with the branch hydraulic pressure path 9e. Yes. The first switching valve 4 is a normally open solenoid valve, and is a master cut valve that shuts off the upstream side and the downstream side of the first main hydraulic pressure passage 9a by switching to a closed state.

  The second main hydraulic pressure passage 9b is provided with a second switching valve 5 that opens and closes the second main hydraulic pressure passage 9b. The second switching valve 5 is a normally open solenoid valve, and is a master cut valve that shuts off the upstream side and the downstream side of the second main hydraulic pressure passage 9b by switching to a closed state.

  The branch hydraulic pressure passage 9e is provided with an on-off valve 6 that is a normally closed electromagnetic valve. The on-off valve 6 opens and closes the branch hydraulic pressure passage 9e.

  The two pressure sensors 8a and 8b detect the magnitude of the brake fluid pressure. Information acquired by both pressure sensors 8 a and 8 b is output to the electronic control unit 7.

The first pressure sensor 8a is provided in the second main hydraulic pressure path 9b. The first pressure sensor 8 a is arranged on the upstream side (master cylinder 1 side) of the second switching valve 5 and detects the brake fluid pressure generated in the master cylinder 1.
The second pressure sensor 8b is provided in the first main hydraulic pressure path 9a. The second pressure sensor 8b is arranged on the downstream side (output port 15a side) with respect to the first switching valve 4, and detects the brake fluid pressure generated in the slave cylinder A2.

  The electronic control unit 7 opens and closes both the switching valves 4 and 5 and the opening / closing valve 6 based on information obtained from various sensors such as the pressure sensors 8a and 8b and the stroke sensor, a program stored in advance, and the like. Control.

Although not shown, the slave cylinder A2 includes a slave piston that slides in the cylinder hole, an actuator mechanism having a motor and a driving force transmission unit, and an electronic control unit.
In the slave cylinder A2, the driving force transmission unit converts the rotational driving force of the motor into an advancing / retreating motion and transmits it to the slave piston. As a result, the slave piston slides in the cylinder hole and pressurizes the brake fluid in the cylinder hole. The brake fluid pressure generated in the slave cylinder A2 is input to the brake fluid pressure generator A1 through the pipes Hc and Hd.

The hydraulic pressure control device A3 can execute anti-lock brake control, skid control and traction control for stabilizing the behavior of the vehicle, by appropriately controlling the brake hydraulic pressure applied to each wheel cylinder W of the wheel brake. It has.
In addition, although illustration is abbreviate | omitted, hydraulic control apparatus A3 is a hydraulic unit provided with an electromagnetic valve, a pump, etc., a motor for driving the pump, an electronic control device for controlling the electromagnetic valve, the motor, etc. It has.
The hydraulic pressure control device A3 is connected to the brake hydraulic pressure generation device A1 via the pipes Ha and Hb, and is connected to each wheel cylinder W via the pipes.

Next, an outline of the operation of the vehicle brake system A will be described.
In the vehicle brake system A, when the stroke sensor detects that the brake pedal P is operated, the electronic control unit 7 switches to a state in which both the switching valves 4 and 5 are closed. As a result, the upstream side and the downstream side of both main hydraulic pressure paths 9a and 9b are blocked.

  In addition, the electronic control unit 7 opens the on-off valve 6. As a result, the brake fluid can flow into the stroke simulator 2 from the first main hydraulic pressure passage 9a through the branch hydraulic pressure passage 9e.

  Both pistons 1a, 1b of the master cylinder 1 receive the depression force of the brake pedal P, slide in the first cylinder hole 11 toward the bottom surface side, and pressurize the brake fluid in both pressure chambers 1e, 1f. At this time, since the upstream side and the downstream side of both main hydraulic pressure passages 9a and 9b are blocked, the brake hydraulic pressure generated in both pressure chambers 1e and 1f is not transmitted to the wheel cylinder W.

When the brake fluid in the first pressure chamber 1e is pressurized, the brake fluid flows from the first main hydraulic pressure passage 9a into the branch hydraulic pressure passage 9e. Then, the brake fluid in the pressure chamber 12 a of the stroke simulator 2 is pressurized, and the piston 21 moves toward the lid member 24 against the urging force of the coil springs 22 and 23.
As a result, the brake pedal P strokes, and the urging force is generated on the piston 21 toward the bottom surface by the coil springs 22 and 23 and the disc spring 25, and the piston 21 is simulated against the brake pedal P. An operational reaction force is applied.

When the depression of the brake pedal P is detected by the stroke sensor, the motor of the slave cylinder A2 is driven.
In the slave cylinder A2, the brake fluid pressure output from the slave cylinder A2 (the brake fluid pressure detected by the second pressure sensor 8b) and the brake fluid pressure output from the master cylinder 1 (detected by the first pressure sensor 8a). And the number of revolutions of the motor is controlled based on the comparison result. In this manner, the brake fluid pressure is generated in the slave cylinder A2 in accordance with the stroke amount of the brake pedal P.

The brake fluid pressure generated in the slave cylinder A2 is input to the brake fluid pressure generator A1 through the pipes Hc and Hd, and the fluid is supplied to the brake fluid pressure paths 9c and 9d, both the main fluid pressure paths 9a and 9b, and the pipes Ha and Hb. Input to the pressure control device A3.
Further, the brake fluid pressure is transmitted from the hydraulic pressure control device A3 to each wheel cylinder W, and each wheel cylinder W is actuated to apply a braking force to each wheel.

In a state where the slave cylinder A2 is not operated (for example, when electric power cannot be obtained), both the switching valves 4 and 5 are opened, and the upstream side and the downstream side of both the main hydraulic pressure passages 9a and 9b. The side is in communication. The on-off valve 6 is closed.
In this state, the brake fluid pressure in both the main fluid pressure passages 9a and 9b is increased by the master cylinder 1. And each wheel cylinder W which leads to both the main hydraulic pressure paths 9a and 9b raises pressure, and braking force is given to a wheel.

Next, a specific configuration of the stroke simulator 2 of the present embodiment will be described.
As shown in FIG. 2, the stroke simulator 2 includes a bottomed second cylinder hole 12 formed in the base body 100, a piston 21 inserted into the second cylinder hole 12, and an opening 12 c of the second cylinder hole 12. And a lid member 24 for closing.
The stroke simulator 2 includes a first coil spring 22 and a second coil spring 23 disposed between the piston 21 and the lid member 24, and a disc spring 25 provided on the lid member 24 (" Elastic member ").

The second cylinder hole 12 is a cylindrical hole with a step and opens on one surface of the base body 100. In the second cylinder hole 12, a pressure chamber 12a is formed from the bottom surface 12d to a substantially central portion in the axial direction, and a storage chamber 12b is formed from the substantially central portion in the axial direction to the opening 12c. . The storage chamber 12b is larger in diameter than the pressure chamber 12a.
In the second cylinder hole 12, a pressure chamber 12a is formed on the distal end side (bottom surface 12d side), and an accommodation chamber 12b is formed on the proximal end side (opening portion 12c side).

  The pressure chamber 12a is a part in which the piston 21 is accommodated. On the inner peripheral surface of the pressure chamber 12a, a holding groove 12g is formed over the entire circumference at a substantially central portion in the axial direction. An annular seal member 12h is fitted in the holding groove 12g.

  On the inner peripheral surface of the pressure chamber 12a, a branch hydraulic pressure passage 9e is opened on the tip side of the holding groove 12g. As shown in FIG. 1, the first pressure chamber 1e of the master cylinder 1 and the pressure chamber 12a of the stroke simulator 2 communicate with each other through a first main hydraulic pressure passage 9a and a branch hydraulic pressure passage 9e.

As shown in FIG. 2, the piston 21 is a cylindrical member with a bottom, and is accommodated in the pressure chamber 12a. The piston 21 can reciprocate in the axial direction within the pressure chamber 12a.
Further, since the inner peripheral portion of the seal member 12h is in contact with the outer peripheral surface of the piston 21, the space between the outer peripheral surface of the piston 21 and the inner peripheral surface of the pressure chamber 12a is sealed in a liquid-tight manner.

  The piston 21 has an opening 21a disposed on the distal end side and a bottom 21b disposed on the proximal end side. A guide portion 21 d is projected from the central portion of the base end surface 21 c of the piston 21. In a state where the tip of the piston 21 is in contact with the bottom surface 12d of the pressure chamber 12a, the guide portion 21d protrudes into the storage chamber 12b.

A plurality of communication holes 21e pass through the distal end portion of the peripheral wall portion of the piston 21. The communication holes 21e are arranged at equal intervals in the circumferential direction of the piston 21.
The inside of the piston 21 communicates with the pressure chamber 12a through the opening 21a and the communication holes 21e. Therefore, when the brake fluid pressure in the pressure chamber 12a increases, the brake fluid pressure in the piston 21 also increases.

  A first guide member 26 is attached to the base end surface 21 c of the piston 21. The first guide member 26 is formed with a bottomed cylindrical portion 26b and a flange 26a formed at an opening edge portion on the distal end side of the cylindrical portion 26b.

The cylindrical portion 26b of the first guide member 26 has an opening on the piston 21 side and a bottom portion on the lid member 24 side. An attachment hole 26c passes through the bottom of the cylindrical portion 26b.
The cylindrical portion 26 b of the first guide member 26 is a part that is fitted on the guide portion 21 d of the piston 21. Further, the cylindrical portion 26 b of the first guide member 26 is a portion that is inserted into the distal end portion of the first coil spring 22.

  The lid member 24 is fitted in the base end portion of the storage chamber 12b and closes the opening 12c of the second cylinder hole 12. The clip member 24c fitted in the groove on the inner peripheral surface of the storage chamber 12b constitutes a stopper for the lid member 24.

A columnar guide portion 24b protrudes from the center portion of the front end surface of the main body portion 24a of the lid member 24. The guide portion 24 b is a portion that is inserted into the proximal end portion of the second coil spring 23.
A concave portion 24d having a circular cross section is formed at the center of the distal end surface of the guide portion 24b of the lid member 24. The recess 24d is a part into which the disc spring 25 is fitted.

  On the outer peripheral surface of the main body 24a of the lid member 24, a holding groove 24e is formed over the entire circumference. An annular seal member 24f is fitted in the holding groove 24e. Since the outer peripheral portion of the seal member 24f is in contact with the inner peripheral surface of the storage chamber 12b, the space between the outer peripheral surface of the lid member 24 and the inner peripheral surface of the storage chamber 12b is sealed in a liquid-tight manner.

  A second guide member 27 is disposed between the piston 21 and the lid member 24. The second guide member 27 is formed with a bottomed cylindrical portion 27b and a flange 27a formed at the opening edge portion on the distal end side of the cylindrical portion 27b.

The cylindrical portion 27b of the second guide member 27 has an opening on the piston 21 side and a bottom portion on the lid member 24 side.
The cylindrical portion 27 b of the second guide member 27 has a larger diameter than the cylindrical portion 26 b of the first guide member 26. The cylindrical portion 26 b of the first guide member 26 is inserted into the cylindrical portion 27 b of the second guide member 27. Further, the cylindrical portion 27 b of the second guide member 27 is a portion that is inserted into the distal end portion of the second coil spring 23.

  The bottom portion of the cylindrical portion 26 b of the first guide member 26 and the bottom portion of the cylindrical portion 27 b of the second guide member 27 are connected via a connecting pin 28. The connecting pin 28 is formed with a shaft portion 28a and a retaining portion 28b formed at the tip of the shaft portion 28a.

  The shaft portion 28 a is inserted through the mounting hole 26 c of the first guide member 26. The shaft portion 28a is slightly smaller in diameter than the mounting hole 26c and is movable in the axial direction with respect to the first guide member 26.

  The retaining portion 28 b is disposed in the cylindrical portion 26 b of the first guide member 26. The retaining portion 28b has a diameter larger than that of the mounting hole 26c. The retaining portion 28b is a portion for preventing the connecting pin 28 from coming off from the first guide member 26 to the proximal end side.

  The base end portion of the shaft portion 28 a of the connecting pin 28 is fixed to the bottom portion of the cylindrical portion 27 b of the second guide member 27. Thus, the second guide member 27 is connected to the first guide member 26 via the connecting pin 28. The second guide member 27 is movable in the axial direction of the second cylinder hole 12 with respect to the first guide member 26 while being guided by the connecting pin 28.

  A cylindrical bush 29 is externally fitted to a portion between the first guide member 26 and the second guide member 27 in the shaft portion 28 a of the connecting pin 28. The bush 29 is an elastic member made of rubber or synthetic resin.

  The first coil spring 22 is housed in the housing chamber 12 b and is interposed between the first guide member 26 and the second guide member 27. The first coil spring 22 is an elastic member in which a metal wire is wound spirally.

A cylindrical portion 26 b of the first guide member 26 is inserted into the distal end portion of the first coil spring 22. Further, the distal end portion of the first coil spring 22 is in contact with the flange 26 a of the first guide member 26.
The proximal end portion of the first coil spring 22 is inserted into the cylindrical portion 27 b of the second guide member 27. Further, the base end portion of the first coil spring 22 is in contact with the bottom portion of the cylindrical portion 27 b of the second guide member 27.

The second coil spring 23 is housed in the housing chamber 12 b and is disposed between the second guide member 27 and the lid member 24. The second coil spring 23 is an elastic member in which a metal wire is spirally wound.
The inner diameter of the second coil spring 23 is formed larger than the outer diameter of the first coil spring 22. Further, the wire diameter of the second coil spring 23 is formed larger than the wire diameter of the first coil spring 22. The spring constant of the second coil spring 23 is set larger than the spring constant of the first coil spring 22.

A guide portion 24 b of the lid member 24 is inserted into the proximal end portion of the second coil spring 23. Moreover, the outer peripheral part of the 2nd coil spring 23 is arrange | positioned near the inner peripheral surface of the storage chamber 12b.
A cylindrical portion 27 b of the second guide member 27, a proximal end portion of the first coil spring 22, and a cylindrical portion 26 b of the first guide member 26 are inserted into the distal end portion of the second coil spring 23. Further, the connecting pin 28 and the bush 29 are also arranged in the second coil spring 23. The tip of the second coil spring 23 is in contact with the flange 27 a of the second guide member 27.
Thus, a part of the first coil spring 22 and a part of the second coil spring 23 overlap in the radial direction of the second cylinder hole 12.

The disc spring 25 is a metal cylindrical elastic member. The disc spring 25 is formed in a truncated cone shape, and the diameter thereof is gradually reduced from the base end portion toward the tip end portion. The disc spring 25 is formed smaller than the second coil spring 23 in the axial direction of the second cylinder hole 12.
The base end portion of the disc spring 25 is press-fitted into the recess 24 d of the lid member 24 and is fixed to the lid member 24. Further, the tip of the disc spring 25 protrudes toward the tip of the recess 24d.
The spring constant of the disc spring 25 is set larger than the spring constant of the second coil spring 23.

  In the stroke simulator 2 of the present embodiment, the first coil spring 22 and the bush 29 are juxtaposed in the radial direction of the second cylinder hole 12. The first coil spring 22 and the second coil spring 23 are connected in series in the axial direction of the second cylinder hole 12. Further, the second coil spring 23 and the disc spring 25 are juxtaposed in the radial direction of the second cylinder hole 12.

The stroke simulator 2 described above operates as follows.
As shown in FIG. 1, in the vehicle brake system A, when the switching valve 4 is closed and the on-off valve 6 is opened, the brake hydraulic pressure generated in the master cylinder 1 is the first main hydraulic pressure path. The pressure is transmitted to the pressure chamber 12a of the stroke simulator 2 through 9a and the branch hydraulic pressure path 9e.

  As shown in FIG. 2, the brake fluid that has flowed into the pressure chamber 12 a flows into the piston 21 through each communication hole 21 e of the piston 21. When the piston 21 is pushed out to the base end side (the cover member 24 side) by the brake fluid pressure in the pressure chamber 12a and the piston 21, as shown in FIG. 3, the first coil spring 22 is moved to the first guide member. 26 and the second guide member 27 contract.

When the first coil spring 22 starts to contract, that is, when the brake fluid pressure in the pressure chamber 12a is small, the first coil spring 22 contracts greatly and the second coil spring 23 hardly contracts. Therefore, when the brake fluid pressure in the pressure chamber 12 a is small, a reaction force mainly due to the reaction force characteristic of the first coil spring 22 acts on the piston 21.
Thereby, an operation reaction force mainly due to a reaction force characteristic of the first coil spring 22 is applied to the brake pedal P (see FIG. 1) (region L1 in a linear B1 in FIG. 5).

  When the brake fluid pressure in the pressure chamber 12a increases, the first guide member 26 contacts the bush 29, and the bush 29 contracts between the first guide member 26 and the second guide member 27. As the amount of contraction of the bush 29 increases, the reaction force acting on the piston 21 from the bush 29 gradually increases.

When the brake fluid pressure in the pressure chamber 12 a further increases, the second coil spring 23 contracts greatly between the second guide member 27 and the lid member 24. A reaction force mainly due to a reaction force characteristic of the second coil spring 23 acts on the piston 21.
As a result, an operation reaction force mainly due to the reaction force characteristic of the second coil spring 23 is applied to the brake pedal P (see FIG. 1) (region L3 of the linear B1 in FIG. 5).

  In the vicinity of the switching point at which the reaction force characteristic of the first coil spring 22 is switched to the reaction force characteristic of the second coil spring 23, the reaction force characteristic of the bush 29 is reduced to the reaction force characteristic of the first coil spring 22 and the second coil spring 23. Since the force characteristic is added, the reaction force acting on the piston 21 from both the coil springs 22 and 23 gradually changes. That is, the operation reaction force of the brake pedal P (see FIG. 1) gradually increases (region L2 of the linear B1 in FIG. 5).

When the brake pedal P (see FIG. 1) approaches the maximum stroke amount, the flange 27a of the second guide member 27 comes into contact with the flange 26a of the first guide member 26 as shown in FIG. Further, when the second coil spring 23 further contracts between the second guide member 27 and the lid member 24, the bottom portion of the cylindrical portion 27 b of the second guide member 27 contacts the disc spring 25. Then, the disc spring 25 contracts between the second guide member 27 and the lid member 24.
Thereby, in addition to the reaction force due to the reaction force characteristic of the second coil spring 23, a reaction force due to the reaction force characteristic of the disc spring 25 acts on the piston 21.
Therefore, an operation reaction force mainly due to the reaction force characteristics of the second coil spring 23 and the disc spring 25 is applied to the brake pedal P (see FIG. 1) (region L4 in the line B1 in FIG. 5).

In the stroke simulator 2 as described above, as shown in FIG. 3, until the stroke amount of the brake pedal P (see FIG. 1) reaches the changing point C (see FIG. 5), the first coil spring 22 and the first An operation reaction force is applied to the brake pedal P by the two-coil spring 23.
Thereafter, when the stroke amount of the brake pedal P reaches a change point C (see FIG. 5), the piston 21 comes into contact with the disc spring 25 as shown in FIG.

  In the stroke simulator 2 of the present embodiment, when the stroke amount of the brake pedal P (see FIG. 1) reaches the changing point C, an operation reaction force is applied to the brake pedal P by the two coil springs 22 and 23 and the disc spring 25. Is done. As a result, as shown in FIG. 5, with the change point C as a boundary, the increase amount of the operation reaction force with respect to the increase amount of the stroke amount of the brake pedal P is clearly increased, and the slope of the linear B1 is increased.

In addition, the linear B2 shown in FIG. 5 has shown the reaction force characteristic in the case of transmitting the brake fluid pressure of the master cylinder 1 (refer FIG. 1) to the wheel cylinder W (refer FIG. 1). In the line B2, there is a changing point at which the inclination clearly increases near the maximum stroke amount of the brake pedal P (see FIG. 1).
In the stroke simulator 2 of the present embodiment, the interval between the piston 21 (second guide member 27) and the disc spring 24 is set so that the change point C of the line B1 approximates the change point of the line B2 (see FIG. 2).
That is, when the stroke amount of the brake pedal P reaches an amount that approximates the changing point of the linear B, the piston 21 contacts the disc spring 25 as shown in FIG.

  Thus, in the stroke simulator 2 of the present embodiment, the reaction force characteristic of the operation reaction force applied to the brake pedal P transmits the brake fluid pressure of the master cylinder 1 to the wheel cylinder W as shown in FIG. It approximates the reaction force characteristic in the case of (see FIG. 5). Therefore, in the stroke simulator 2 of the present embodiment, the uncomfortable feeling during the brake operation can be alleviated.

Moreover, in the stroke simulator 2 of this embodiment, since the 2nd coil spring 23 and the disc spring 25 are arranged in parallel by the radial direction of the 2nd cylinder hole 12, as shown in FIG. The second cylinder hole 12 can be reduced in the axial direction, and the base body 100 can be reduced in size as compared with the case where the base body 100 is disposed.
Moreover, in the stroke simulator 2 of this embodiment, since the disc spring 25 is arrange | positioned inside the 2nd coil spring 23, it can prevent that the 2nd cylinder hole 12 becomes large in radial direction.
Moreover, in the stroke simulator 2 of this embodiment, since the disk spring 25 is used, a spring load can be taken out with a small stroke amount compared with the case where a coil spring is used, and the axial length of the stroke simulator 2 is made smaller. can do.
And as shown in FIG. 1, the brake system A for vehicles can be reduced in size by using the stroke simulator 2 of this embodiment.

The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.
In the present embodiment, as shown in FIG. 2, the disc member 25 is provided on the lid member 24, but the configuration of the elastic member provided on the lid member 24 is not limited. For example, a disc-shaped spring member such as a wave washer or an elastic member made of rubber or synthetic resin can be used. And the operation reaction force given to the brake pedal P (refer FIG. 1) can be set to a desired reaction force characteristic by using various elastic members.

  In this embodiment, the spring constant of the disc spring 25 is set to be larger than the spring constant of the second coil spring 23, but even if the spring constant of the disc spring 25 is set to be equal to or less than the spring constant of the second coil spring 23. Good.

  In the present embodiment, as shown in FIG. 1, the master cylinder 1 and the stroke simulator 2 are provided in the base body 100, but the master cylinder 1 and the stroke simulator 2 may be formed separately. Furthermore, the master cylinder 1, the stroke simulator 2, and the slave cylinder A2 may be provided on one base.

DESCRIPTION OF SYMBOLS 1 Master cylinder 2 Stroke simulator 3 Reservoir 4 1st switching valve 5 2nd switching valve 6 On-off valve 7 Electronic controller 9a 1st main hydraulic pressure path 9b 2nd main hydraulic pressure path 9e Branching hydraulic pressure path 11 1st cylinder hole 12 Second cylinder hole 12a Pressure chamber 12b Storage chamber 12d Bottom surface 21 Piston 21b Bottom portion 24 Lid member 24a Body portion 24b Guide portion 24d Recessed portion 25 Disc spring (elastic member)
26 First guide member 26a Flange 26b Cylindrical portion 27 Second guide member 27a Flange 27b Cylindrical portion 28 Connecting pin 29 Bush 100 Base body A Brake system for vehicle A1 Brake hydraulic pressure generator A2 Slave cylinder A3 Hydraulic pressure control device P Brake pedal ( Brake operator)
W Wheel cylinder

Claims (5)

A stroke simulator for applying an operation reaction force to a brake operator,
A bottomed cylinder hole formed in the substrate;
A piston inserted into the cylinder hole;
A lid member for closing the opening of the cylinder hole;
A coil spring disposed between the piston and the lid member;
An elastic member provided on the lid member,
The coil spring and the elastic member are juxtaposed in the radial direction of the cylinder hole,
A stroke simulator characterized in that the elastic member is smaller than the coil spring in the axial direction of the cylinder hole.   The stroke simulator according to claim 1, wherein a spring constant of the elastic member is larger than a spring constant of the coil spring.   The stroke simulator according to claim 1, wherein the elastic member is disposed inside the coil spring.   The stroke simulator according to any one of claims 1 to 3, wherein the elastic member is a disc-shaped leaf spring member. A brake system for a vehicle,
A brake fluid pressure generating device for generating brake fluid pressure according to the operation amount of the brake operator;
A stroke simulator according to any one of claims 1 to 4,
The vehicle brake system according to claim 1, wherein the stroke simulator is provided on the base body of the brake fluid pressure generator.

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