JP2013256263A - Brake stroke simulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake stroke simulator capable of further improving a feeling of brake operation.SOLUTION: A brake stroke simulator 1 having a housing 2 filled with fluid 3 includes: an orifice 13 where the fluid 3 can pass between a first chamber 4 serially disposed in the housing 2 and including a first spring 10 and a second chamber 5 including a second spring 11.

Description

  The present invention relates to a brake stroke simulator.

  Conventionally, hybrid vehicles and electric vehicles use electronically controlled brakes, and the pedal force and stroke of the brake pedal are created by operating the piston inside the stroke simulator according to the hydraulic pressure generated by the master cylinder during system control. . Here, in conventional hybrid vehicles and electric vehicles, the elastic force of the spring and rubber built in the stroke simulator is used as a reaction force against the brake pedal, so the feeling of spring is strong, and the usual brake booster tower mounted vehicle and There is a big difference in the feeling of braking operation.

  Therefore, in recent years, techniques for improving the braking operation feeling have been reported. For example, Patent Document 1 discloses a stroke simulator including three springs having different spring constants. Patent Document 2 discloses a simulator piston having an orifice between a liquid chamber having a spring and a liquid chamber having no spring. Patent Document 3 discloses a vehicle brake hydraulic pressure generator that includes an orifice between a master cylinder and a stroke simulator.

JP 2004-330966 A JP 2003-252196 A JP 2000-335402 A

  However, in the prior art (Patent Documents 1 to 3, etc.), the operation force felt by the brake pedal is generated by a spring inside the stroke simulator, so that natural braking such as a vehicle equipped with a brake booster that uses negative pressure is performed. There is no operational feeling.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brake stroke simulator that can further improve the braking operation feeling.

  The present invention is a brake stroke simulator in which a housing is filled with fluid, and is provided between a first chamber having a first spring and a second chamber having a second spring, which are arranged in series in the housing. And an orifice through which the fluid can pass.

  In the brake stroke simulator, the first spring is compressed by a braking operation force, the second spring is compressed after the first spring is compressed, and when the first spring is compressed, the first spring is compressed in the first chamber. Preferably, the fluid passes through the orifice and moves to the second chamber, and when the second spring is compressed, the fluid in the second chamber passes through the orifice and moves to the first chamber.

  In the brake stroke simulator, the orifice is preferably provided with a mechanism for changing an opening area.

  In the brake stroke simulator, the mechanism may be configured so that the fluid moves from the second chamber to the first chamber rather than the opening area when the fluid moves from the first chamber to the second chamber. It is preferable that the opening area changes so as to increase.

  The brake stroke simulator further includes a third chamber having a third spring disposed on the opposite side of the first chamber across the second chamber from the housing, and when the first spring is compressed, Preferably, the third spring is compressed to enlarge the second chamber.

  The brake stroke simulator according to the present invention suppresses the spring feeling peculiar to the stroke simulator, and can approximate the FS characteristic as obtained with a brake booster tower mounted vehicle, and as a result, the braking operation feeling is further improved. There is an effect that can be made.

FIG. 1 is a schematic cross-sectional view illustrating an example of a brake stroke simulator according to the first embodiment of the present invention. FIG. 2 is a graph showing an example of the FS characteristic of the brake booster. FIG. 3 is a graph showing an example of the FS characteristic of a conventional stroke simulator. FIG. 4 is a graph comparing the FS characteristics among the brake booster at the time of rapid depression, the conventional stroke simulator, and the brake stroke simulator of the present invention. FIG. 5 is a schematic cross-sectional view illustrating an example of a brake stroke simulator according to the second embodiment of the present invention. FIG. 6 is a schematic sectional view showing an example of a brake stroke simulator according to the third embodiment of the present invention.

  Embodiments of a brake stroke simulator according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment.

Embodiment 1
FIG. 1 is a schematic sectional view showing an example of a brake stroke simulator 1 according to the first embodiment of the present invention.

  In the first embodiment, as shown in FIG. 1, the brake stroke simulator 1 absorbs a stroke corresponding to a braking (brake) operation force and generates a brake reaction force. In the brake stroke simulator 1, a hollow cylindrical housing 2 is provided with an opening 2a on one end side in the axial direction inside. Note that the other end of the housing 2 is closed. The opening 2 a communicates with a first space 2 b provided in the housing 2. The diameter of the first space 2b is larger than the diameter of the opening 2a. The first space portion 2 b communicates with the second space portion 2 c provided in the housing 2. The diameter of the second space 2c is larger than the diameter of the first space 2b. The housing 2 supports the first piston 7 so as to be movable along the axial direction in the opening 2a and the first space 2b. The outer peripheral portion of the first piston 7 is in sliding contact with the inner peripheral surface of the housing 2 when moving along the axial direction. The first piston 7 has a shaft portion 7a on which a force from the outside of the brake simulator 1 acts, and a first pressing portion 7b having a disk shape. The first piston 7 has a brake oil pressure as a braking operation force generated in a compression direction (in the direction of the arrow in FIG. 1) that is a direction on the other end side of the housing 2 from a hydro booster or a master cylinder (not shown). It is comprised so that it may act on 7a.

  As shown in FIG. 1, a first chamber 4 and a second chamber 5 filled with fluid 3 are arranged in series in the housing 2.

  Here, the first chamber 4 is formed between the first pressing portion 7b of the first piston 7 and the second piston 8 in the first space portion 2b and the second space portion 2c. Between the 1st piston 7 and the 2nd piston 8, the compression coil spring as the 1st spring 10 is provided in the state compressed in the initial position, when the braking operation force is not acting. This initial position is a state in which the first pressing portion 7b of the first piston 7 is in contact with the first step portion formed at the boundary between the opening 2a of the housing 2 and the first space portion 2b. There is a position where the second piston 8 is in contact with a second step portion formed at the boundary between the first space portion 2b and the second space portion 2c. The housing 2 supports the second piston 8 so as to be movable in the axial direction in the second space 2c. The outer peripheral portion of the second piston 8 is in sliding contact with the inner peripheral surface of the housing 2 when moving along the axial direction. The 2nd piston 8 has the projection part 8a for positioning the 1st spring 10, and the 2nd press part 8b which makes a disk shape. The protrusion 8a may be made of an elastic material such as rubber. The diameter of the second pressing portion 8 b of the second piston 8 is larger than the diameter of the pressing portion 7 a of the first piston 7. The second pressing portion 8b of the second piston 8 is provided with a plurality of through holes as an orifice 13 through which the fluid 3 can pass at equal intervals in a circumferential shape. For example, four orifices 13 are provided in the second pressing portion 8 b of the second piston 8. The second piston 8 is configured such that a braking operation force generated in the compression direction acts via the first piston 7 and the first spring 10.

  The second chamber 5 is formed by the second pressing portion 8b of the second piston 8 and the inner peripheral surface on the other end side of the housing 2 in the second space 2c. A compression coil spring as the second spring 11 is compressed between the second piston 8 and the inner peripheral surface on the other end side of the housing 2 at the initial position when no braking operation force is applied. Provided in a state. This initial position is a state in which the second pressing portion 8b of the second piston 8 is in contact with the second step portion formed at the boundary between the first space portion 2b and the second space portion 2c of the housing 2. The position of

  In this case, the 1st piston 7 and the 2nd piston 8 which are arrange | positioned in series in the housing 2 function as a piston of this embodiment. The first piston 7 can be advanced by a braking hydraulic pressure (braking operation force) acting on the shaft portion 7 a, and is retracted with respect to the housing 2 by the urging force of the first spring 10, that is, the first piston 7 first The pressing portion 7 b is urged and supported at a position where it comes into contact with the first step portion of the housing 2. The second piston 8 can be moved forward by being pressed by the first piston 7 via the first spring 10, and is moved backward with respect to the housing 2 by the urging force of the second spring 11, that is, the second piston 8 has the second piston 8. The two pressing portions 8b are urged and supported at positions where they contact the second stepped portions.

  Here, the spring constant of the first spring 10 is smaller than the spring constant of the second spring 11. At this time, in the brake simulator 1, when a braking operation force is applied to the first piston 7, the first spring 10 is compressed by the braking operation force and the first chamber 4 becomes small. When a braking operation force is further applied, the second spring 11 is compressed after the first spring 10 is compressed. On the other hand, when the braking operation force no longer acts on the first piston 7, the first piston 7 and the second piston 8 move in the direction opposite to the compression direction by the reaction force of the first spring 10 and the second spring 11. Moving.

  As described above, in the brake stroke simulator 1A of the present embodiment, the first piston 10 moves forward by the braking hydraulic pressure acting on the shaft portion 7a, whereby the first spring 10 is elastically deformed, and then the first piston 7 is The second spring 11 is elastically deformed by pressing the piston 8 and moving forward. At this time, in this embodiment, while the first piston 7 moves forward, the fluid 3 in the first chamber 4 is transferred to the reservoir tank 16 provided outside the housing 2 via the hose 15 having a through hole inside. Moving. Further, when the first piston is in contact with the protrusion 8 a of the second piston 8 and is pushed by the first piston 7 to advance, the fluid 3 in the second chamber 5 passes through the orifice 13. Then, it moves to the first chamber 4 and moves to the reservoir tank 16. At this time, since the fluid 3 generates a flow resistance that passes through the orifice 13, the second piston 8 is difficult to move forward. Thereafter, when the occupant returns the brake pedal, the braking operation force no longer acts on the first piston 7, and the first piston 7 and the second piston 8 are compressed in the compression direction by the reaction force of the first spring 10 and the second spring 11. The fluid 3 is returned from the reservoir tank 16 to the first chamber 4 and the second chamber 5.

  Here, the operation of the brake stroke simulator 1A of the first embodiment will be specifically described.

  For example, when the occupant depresses the brake pedal, braking oil pressure is generated according to the brake stroke, and this braking oil pressure acts on the shaft portion 7 a of the first piston 7. Then, the first piston 7 moves forward (moves leftward in FIG. 1) against the urging force of the first spring 10 by the braking hydraulic pressure applied to the shaft portion 7a, so that the first spring 10 is moved. Shrink and elastically deform. At this time, while the first piston 7 moves forward, the fluid 3 in the first chamber 4 moves to the reservoir tank 16 via the hose 15 having a through-hole through which the fluid 3 can pass.

  When the occupant further depresses the brake pedal, the first piston 7 presses the second piston 8 in a state where the first piston is in contact with the protrusion 8 a of the second piston 8. At this time, since the fluid 3 in the second chamber 5 passes through the orifice 13 and moves to the first chamber 4, the fluid 3 generates a flow resistance that passes through the orifice 13, so that the second piston 8 is difficult to advance. Become. That is, in this case, the first piston 7 further moves forward against the biasing force of the first spring 10, and the fluid 3 passes through the orifice 13 in addition to the biasing force of the second spring 11. By moving forward against the flow resistance, the second spring 11 contracts and elastically deforms. At this time, as shown in (3) of FIG. 4 to be described later, the first spring 10 generates the first brake reaction force up to the vicinity of the stroke value indicated by the third line from the bottom, The flow resistance through which the spring 11 and the fluid 3 pass through the orifice 13 generates the second brake reaction force. Here, the second brake reaction force is larger than the first brake reaction force.

  When the occupant releases the brake pedal, the braking hydraulic pressure corresponding to the brake stroke is not generated, and this braking hydraulic pressure does not act on the shaft portion 7a of the first piston 7. Then, the first piston 7 and the second piston 8 retreat (move to the right in FIG. 1) by the urging force of the first spring 10 and the second spring 11 to return to the initial position.

  Here, an example of the result of the pedaling force-stroke characteristic (FS characteristic) when the brake stroke simulator 1 of the present embodiment described above is operated will be described with reference to FIGS. FIG. 2 is a diagram illustrating an example of the FS characteristic of the brake booster. FIG. 3 is a diagram illustrating an example of the FS characteristic of a conventional stroke simulator. FIG. 4 is a graph comparing the FS characteristics among the brake booster at the time of rapid depression, the conventional stroke simulator, and the brake stroke simulator of the present invention.

  In the prior art (Patent Documents 1 to 3, etc.), the operating force felt by the brake pedal is generated by a spring inside the stroke simulator, so that a natural braking operation fee such as a vehicle equipped with a brake booster that uses negative pressure is used. It does not become a ring. In particular, as shown in FIG. 2 and FIG. 3, the difference in the FS characteristic increases depending on the pedal operation speed between the brake booster and the conventional stroke simulator.

  FIG. 2 and FIG. 3 show an example of changes in the FS characteristic when the stepping speed (pedal operating speed) is changed between a slow stepping speed, a medium / low stepping speed, and a fast stepping speed. 2 and 3, the vertical axis indicates the stroke “S (mm)” as the operation amount of the brake pedal, and the horizontal axis indicates the pedaling force “F (N)” as the operation force of the brake pedal. ing. The arrow symbol indicates that the stepping speed increases from the upper left to the lower right.

  As shown in FIG. 2 (i), the brake booster shows an FS characteristic that changes with a similar pedal force gradient regardless of the change in the depression speed. Specifically, the brake booster shows a pattern in which the pedal force gradient gradually decreases (that is, the brake pedal gradually increases) regardless of whether the depression speed is slow or fast. On the other hand, as shown in (ii) of FIG. 3, in the conventional stroke simulator, the pedaling force gradient increases from the vicinity of the stroke value indicated by the third line from the bottom during the rapid stepping (at the time of fast depression). This indicates that the brake pedal becomes lighter from around the stroke value indicated by the third line from the bottom.

  Thus, in the conventional stroke simulator, the FS characteristic changes depending on the depression speed. This is because the reaction force generated by the conventional stroke simulator is an elastic force of the spring, and therefore the influence of the spring feeling is strong. For this reason, the conventional stroke simulator does not have a moist texture such as a brake booster, when the pedal is slowly depressed, and when it is depressed quickly, a feeling of rigidity appears. Thus, the conventional technology has room for improvement in consideration of the effect of the spring feeling peculiar to the stroke simulator.

  Therefore, the brake stroke simulator 1 of the present embodiment includes a first chamber 4 including a first spring 10 and a second chamber 5 including a second spring 11 that are arranged in series in a housing 2 filled with fluid 3. Are provided with an orifice 13 through which the fluid 3 can pass. In this case, the first spring 10 is compressed by the braking operation force, and after the first spring 10 is compressed, the second spring 11 is compressed. At this time, when the first spring 10 is compressed, the fluid 3 in the first chamber 4 moves to the reservoir tank 16, and when the second spring 11 is compressed, the fluid 3 in the second chamber 5 passes through the orifice 13. Then, it moves to the first chamber 4.

  That is, paying attention to the range indicated by (iii) in FIG. 4, in the brake stroke simulator 1A of the present embodiment, as shown in (3) in FIG. After the start-up absorption stroke taking into account the occurrence of the first absorption stroke (first brake reaction force) at the initial stage of operation until the vicinity of the stroke value indicated by the third line from the bottom, the braking force is subsequently generated. A second absorption stroke (second brake reaction force) for adjusting the pressure is generated. The pedaling force gradient pattern of the brake stroke simulator 1A shown in FIG. 4 (3) is similar to the pedaling force gradient pattern of the brake booster shown in FIG. 4 (1). On the other hand, the pedaling force gradient pattern of the conventional stroke simulator shown in (2) of FIG. 4 has a large pedaling force gradient from the vicinity of the stroke value indicated by the third line from the bottom (that is, from where the brake pedal is heavy, It is light in the vicinity of the stroke value indicated by the third line from the bottom), which is different from other pedaling force gradient patterns.

  On the other hand, as shown in FIG. 4 (3), the brake stroke simulator 1A has a smaller pedaling force gradient from the vicinity of the stroke value indicated by the third line from the bottom, and the brake pedal is the third from the bottom. It is heavier near the stroke value indicated by the line. This is because, unlike the conventional stroke simulator, the brake stroke simulator 1 </ b> A of the present embodiment is provided with an orifice 13 in the second piston 8 and can move the fluid 3 between the first chamber 4 and the second chamber 5. This is because the spring feeling is suppressed by adding flow resistance to the reaction force of the spring. For this reason, when the stepping speed is high, the second spring 11 is difficult to move. As a result, the brake stroke simulator 1A makes it difficult for the fluid 3 to flow when the brake pedal is operated quickly, and gives a sense of rigidity. When the brake pedal is operated slowly, the fluid 3 passes through the orifice 13 and the piston moves. A braking operation feeling like a brake booster can be realized. On the other hand, in the conventional stroke simulator, since the orifice is not provided between the first chamber and the second chamber, the influence of the spring feeling peculiar to the stroke simulator cannot be suppressed, and is shown in (2) of FIG. Thus, at the time of rapid depressing, the second piston is easy to move forward after the first piston is advanced to the vicinity of the stroke value indicated by the third line from the bottom (that is, from the point where the brake pedal is heavy, It is lighter near the stroke value indicated by the third line from the bottom).

  As described above, in the brake stroke simulator 1A of the first embodiment, the first chamber 4 including the first spring 10 and the second chamber 5 including the second spring 11 arranged in series with the housing 2; Since the orifice 13 through which the fluid 3 can pass is provided, the flow resistance can be added to the reaction force of the spring. As a result, it is possible to suppress the spring feeling peculiar to the stroke simulator and to bring it closer to the FS characteristic as obtained with the brake booster tower mounted vehicle. As a result, it is possible to further improve the braking operation feeling.

[Embodiment 2]
FIG. 5 is a schematic cross-sectional view showing an example of a brake stroke simulator 1B according to the second embodiment of the present invention.

  In the brake stroke simulator of the present invention, as shown in the second embodiment, the third chamber 6 may be provided without providing the reservoir tank 16. Details of the second embodiment will be described below. Note that a description of parts common to the first embodiment will be omitted.

  In the second embodiment, as shown in FIG. 5, a first chamber 4 and a second chamber 5 filled with fluid 3 and a third chamber (air chamber) 6 are arranged in series in the housing 2. Yes.

  Here, the second chamber 5 is formed between the second pressing portion 8b of the second piston 8 and the third piston 9 in the second space 2c. A compression coil spring as the second spring 11 is provided between the second piston 8 and the third piston 9 in a state of being compressed at the initial position when no braking operation force is applied. This initial position is a state in which the second pressing portion 8b of the second piston 8 is in contact with the second step portion formed at the boundary between the first space portion 2b and the second space portion 2c of the housing 2. And the third piston 9 is in a state where the elastic forces of the second spring 11 and the third spring 12 are balanced in the second space 2c. The housing 2 supports the third piston 9 so as to be movable along the axial direction. An O-ring 9 a is provided on the outer periphery of the third piston 9. The outer peripheral portion of the third piston 9 is in sliding contact with the inner peripheral surface of the housing 2 when moving along the axial direction. The third piston 9 is configured such that an internal pressure in the second chamber 5 that increases due to a braking operation force generated in the compression direction acts.

  The third chamber 6 is formed by the third piston 9 and the inner peripheral surface on the other end side of the housing 2 in the second space 2c. A compression coil spring as the third spring 12 is compressed between the third piston 9 and the inner peripheral surface on the other end side of the housing 2 at the initial position described above when no braking operation force is applied. It is provided in the state. Although not shown, it is assumed that the third chamber 6 is provided with one or a plurality of air holes.

  In this case, the 1st piston 7, the 2nd piston 8, and the 3rd piston 9 which are arrange | positioned in series in the housing 2 function as a piston of this embodiment. The first piston 7 can be advanced by a braking hydraulic pressure (braking operation force) acting on the shaft portion 7 a, and is retracted with respect to the housing 2 by the urging force of the first spring 10, that is, the first piston 7 has a first position. The pressing portion 7 b is urged and supported at a position where it comes into contact with the first step portion of the housing 2. The second piston 8 can be moved forward by being pressed by the first piston 7 via the first spring 10, and is moved backward with respect to the housing 2 by the urging force of the second spring 11, that is, the second piston 8 has the second piston 8. The two pressing portions 8b are urged and supported at positions where they contact the second stepped portions. The third piston 9 can be pushed forward by an increase in the internal pressure in the second chamber 5, and can move forward with respect to the housing 2 by the urging force of the third spring 12, that is, the second space 2 c of the housing 2. The second spring 11 and the third spring 12 are biased and supported at a position where the elastic forces of the second spring 11 and the third spring 12 are balanced.

  Here, the spring constant of the first spring 10 is smaller than the spring constant of the third spring 12. Further, the spring constant of the third spring 12 is smaller than the spring constant of the second spring 11. At this time, in the brake simulator 1, when a braking operation force is applied to the first piston 7, the first spring 10 is compressed by the braking operation force and the first chamber 4 becomes small. When the first spring 10 is compressed, the third spring 12 is compressed by the increase in the internal pressure in the second chamber 5 and the second chamber 5 is enlarged. When a braking operation force is further applied, the second spring 11 is compressed after the first spring 10 and the third spring 12 are compressed. On the other hand, when the braking operation force no longer acts on the first piston 7, the reaction force of the first spring 10, the second spring 11, and the third spring 12 causes the first piston 7 and the second piston 8. , And the third piston 9 moves in the direction opposite to the compression direction.

  Thus, in the brake stroke simulator 1 of the present embodiment, the first spring 10 is advanced by the braking hydraulic pressure acting on the shaft portion 7a, whereby the first spring 10 is elastically deformed, and then the first piston 7 is The second spring 11 is elastically deformed by pressing the piston 8 and moving forward. At this time, in the present embodiment, while the first piston 7 moves forward, the fluid 3 in the first chamber 4 moves through the orifice 13 provided in the second piston 8 to the second chamber 5. On the other hand, when the second piston 8 moves forward by being pressed by the first piston 7, the fluid 3 in the second chamber 5 moves to the first chamber 4 through the orifice 13. At this time, since the fluid 3 generates a flow resistance that passes through the orifice 13, the second piston 8 is difficult to move forward.

  Here, the operation of the stroke simulator 1B of the second embodiment will be specifically described.

  For example, when the occupant depresses the brake pedal, braking oil pressure is generated according to the brake stroke, and this braking oil pressure acts on the shaft portion 7 a of the first piston 7. Then, the first piston 7 moves forward (moves leftward in FIG. 5) against the urging force of the first spring 10 by the braking hydraulic pressure applied to the shaft portion 7a, so that the first spring 10 is moved. Shrink and elastically deform. At this time, the third piston 9 moves forward (moves to the left in FIG. 5) against the urging force of the third spring 12 in accordance with the increase in the internal pressure in the second chamber 5. 3 The spring 12 contracts and elastically deforms. As a result, since the second chamber 5 becomes large, the fluid 3 in the first chamber 4 passes through the orifice 13 provided in the second piston 8 and moves to the second chamber 5 while the first piston 7 moves forward. Moving.

  When the occupant further depresses the brake pedal, the first piston 7 presses the second piston 8. At this time, since the fluid 3 in the second chamber 5 passes through the orifice 13 and moves to the first chamber 4, the fluid 3 generates a flow resistance that passes through the orifice 13, so that the second piston 8 is difficult to advance. Become. That is, in this case, the first piston 7 further moves forward against the biasing force of the first spring 10, and the fluid 3 passes through the orifice 13 in addition to the biasing force of the second spring 11. By moving forward against the flow resistance, the second spring 11 contracts and elastically deforms. At this time, as shown in (3) of FIG. 4 described above, the first spring 10 generates the first brake reaction force up to the vicinity of the stroke value indicated by the third line from the bottom. The flow resistance through which the spring 11 and the fluid 3 pass through the orifice 13 generates the second brake reaction force. Here, the second brake reaction force is larger than the first brake reaction force.

  When the occupant releases the brake pedal, the braking hydraulic pressure corresponding to the brake stroke is not generated, and this braking hydraulic pressure does not act on the shaft portion 7a of the first piston 7. Then, the first piston 7, the second piston 8, and the third piston 9 move backward by the urging force of the first spring 10, the second spring 11, and the third spring 12 (moves to the right in FIG. 5). ) To return to the initial position.

[Embodiment 3]
FIG. 6 is a schematic cross-sectional view showing an example of a brake stroke simulator 1C according to the third embodiment of the present invention.

  As shown in FIG. 6, in the third embodiment, the brake stroke simulator 1 </ b> C is provided with a mechanism 14 that changes the opening area of the orifice 13 in a part of the plurality of orifices 13. The mechanism 14 is configured so that the opening area when the fluid 3 moves from the second chamber 5 to the first chamber 4 is larger than the opening area when the fluid 3 moves from the first chamber 4 to the second chamber 5. Change. As shown in FIG. 6, when the mechanism 14 is a valve that can be opened and closed, for example, the valve opens when the braking operation force is lost, thereby increasing the speed at which the fluid 3 moves from the second chamber 5 to the first chamber 4. This is faster than the speed at which the fluid 3 moves from the first chamber 4 to the second chamber 5. As a result, the speed at which the first piston 7, the second piston 8, and the third piston 9 return to the initial position is made faster than the speed at which the first piston 7, the second piston 8, and the third piston 9 move forward. . Other structures are the same as those of the first embodiment shown in FIG.

  According to the third embodiment, by attaching a valve to a part of the plurality of orifices 13, it is possible to provide hysteresis characteristics on the stepping side and the return side of the pedal. Also, change the valve opening (for example, full open, half open, etc.), the number of valves (for example, three orifices with valves and one with no valve), and the type of valve (for example, reverse valve) Thus, it is possible to tune the brake pedal operation feeling desired by the occupant.

  In the above embodiment, the example in which the four pistons 13 are provided in the second piston 8 has been described, but the number of the orifices 13 is not limited to this. The number of the orifices 13 is a number adjusted in advance so that an appropriate flow resistance is generated according to the size of the housing 2 and the capacity of the fluid 3 filled in the first chamber 4 and the second chamber 5. Good. The diameter of the orifice 13 may be adjusted in advance so as to generate an appropriate flow resistance.

  Moreover, in the said embodiment, although the three springs, the 1st spring 10, the 2nd spring 11, and the 3rd spring 12, were arrange | positioned in series with the housing 2, the example was not limited to this. For example, the first spring 10 and the second spring 11 may be configured as one spring. In this case, an unequal pitch spring or a conical spring may be used as one spring. When an unequal pitch spring or a conical spring is used, the first piston 7 is disposed on one end of the spring, the second piston 8 is incorporated in the spring, and the third piston is disposed on the other end of the spring. 9 is arranged.

  Moreover, in the said embodiment, although the case where the braking operation force acted with respect to the 1st piston 7 was demonstrated to the example, it is not limited to this. The order of arrangement of the three chambers, the first chamber 4, the second chamber 5, and the third chamber 6 filled with the fluid 3, and the spring constants of the first spring 10, the second spring 11, and the third spring 12 are large. If the order is the same, the same effect can be obtained even if the braking operation force is applied from the other end of the housing 2.

1A, 1B, 1C Brake stroke simulator 2 Housing 2a Opening 2b 1st space 2c 2nd space 3 Fluid 4 1st chamber 5 2nd chamber 6 3rd chamber 7 1st piston 7a Shaft 7b 1st press part 8 Second piston 8a Protrusion 8b Second pressing portion 9 Third piston 9a O-ring 10 First spring 11 Second spring 12 Third spring 13 Orifice 14 Mechanism 15 Hose 16 Reservoir tank

Claims (5)

A brake stroke simulator in which the housing is filled with fluid,
A brake stroke simulator, comprising an orifice through which the fluid can pass between a first chamber having a first spring and a second chamber having a second spring, which are arranged in series with the housing. The first spring is compressed by a braking operation force, and after the first spring is compressed, the second spring is compressed,
When the first spring is compressed, the fluid in the first chamber passes through the orifice and moves to the second chamber. When the second spring is compressed, the fluid in the second chamber is moved to the orifice. 2. The brake stroke simulator according to claim 1, wherein the brake stroke simulator moves to the first chamber after passing through the first stroke.   The brake stroke simulator according to claim 1 or 2, wherein the orifice is provided with a mechanism for changing an opening area.   In the mechanism, the opening area when the fluid moves from the second chamber to the first chamber is larger than the opening area when the fluid moves from the first chamber to the second chamber. The brake stroke simulator according to claim 3, wherein the brake stroke simulator changes as follows. A third chamber provided with a third spring, disposed on the opposite side of the first chamber with the second chamber sandwiched between the housing;
The brake stroke simulator according to any one of claims 1 to 4, wherein when the first spring is compressed, the third spring is compressed and the second chamber is enlarged.

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