JP7509052B2 - Brake fluid pressure generating device for vehicle and brake device for vehicle - Google Patents

Description

Embodiments of the present invention relate to a vehicle brake fluid pressure generating device and a vehicle brake device.

Conventionally, a hydraulic pressure generating device is known in which a pedal is connected to a master cylinder of a hydraulic system. For example, when the pedal is depressed by a driver of a vehicle, it linearly moves a piston of the master cylinder (Patent Document 1).

US Patent Application Publication No. 2017/0043662

However, in the conventional configuration, the direction of movement of the master cylinder piston extends approximately in the longitudinal direction of the vehicle. This results in an increase in the size of the hydraulic pressure generating device in the longitudinal direction of the vehicle.

The present invention has been made in consideration of the above, and provides a vehicle brake fluid pressure generating device that can be made compact, and a vehicle brake device that allows the vehicle brake fluid pressure generating device to be made compact.

As an example, a vehicle brake fluid pressure generating device according to an embodiment of the present invention includes a pedal having a base attached to a floor surface of a vehicle, a first part, and a second part spaced from the first part and connected to the base so as to be rotatable about a first rotation axis, the first part being moved toward or away from the floor surface by rotating about the first rotation axis, a housing, a piston at least partially contained in the housing and capable of reciprocating relative to the housing, a first connection part provided on one of the housing and the piston and connected to the pedal so as to be rotatable about a second rotation axis, and a second connection part provided on the other of the housing and the piston and connected to the base so as to be rotatable about a third rotation axis, and a master cylinder having an imaginary half line extending from the second rotation axis and passing through the third rotation axis intersecting the floor surface. Therefore, as an example, the distance between the first rotation axis and the third rotation axis in the front-rear direction of the vehicle along the floor surface is shorter than when the half line extends approximately parallel to the floor surface. Therefore, the vehicle brake fluid pressure generating device can be made smaller in size in the front-rear direction of the vehicle.

FIG. 1 is a schematic diagram showing the configuration of a brake device according to a first embodiment. FIG. 2 is a perspective view showing the master cylinder unit of the first embodiment. FIG. 3 is a side view showing the master cylinder unit of the first embodiment. FIG. 4 is a side view diagrammatically illustrating the positions of the first rotation axis, the second rotation axis, and the third rotation axis in the first embodiment. FIG. 5 is a perspective view showing a master cylinder unit according to the second embodiment. FIG. 6 is a side view showing the master cylinder unit of the second embodiment.

First Embodiment
The first embodiment will be described below with reference to FIGS. 1 to 4. In this specification, components according to the embodiment and descriptions of the components may be described in a number of ways. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may be identified by names different from those in this specification. The components may also be described by expressions different from those in this specification.

Figure 1 is a schematic diagram showing the configuration of a brake device 10 according to a first embodiment. The brake device 10 is mounted on a vehicle 1 such as an automobile. The brake device 10 may also be mounted on other vehicles. The brake device 10 is an example of a vehicle brake device. The brake device 10 of this embodiment is, for example, a hydraulic brake. The energy transmission medium in the brake device 10 is not limited to oil, and may be gas or other liquid.

As shown in FIG. 1, the brake device 10 has a pressure unit 11, fluid paths 12, 13, an actuator 14, wheel cylinders 15, 16 that brake the front wheels Wf, wheel cylinders 17, 18 that brake the rear wheels Wr, and a brake ECU (electronic control unit) 19. In this embodiment, the front wheels Wf are driving wheels, and the rear wheels Wr are non-driving wheels. The brake device 10 further has a regenerative control unit and a power supply unit.

The pressurizing unit 11 is connected to the wheel cylinders 15, 16 of the front wheels Wf through a fluid passage 12. The pressurizing unit 11 is connected to the wheel cylinders 17, 18 of the rear wheels Wr through a fluid passage 13. The pressurizing unit 11 is configured to be able to pressurize the wheel cylinders 15 to 18.

The actuator 14 is provided between the pressure applying section 11 and the wheel cylinders 15 to 18. The actuator 14 has a first hydraulic pressure output section 14a and a second hydraulic pressure output section 14b. The first hydraulic pressure output section 14a is provided in the hydraulic path 12 and adjusts the pressure in the wheel cylinders 15 and 16. The second hydraulic pressure output section 14b is provided in the hydraulic path 13 and adjusts the pressure in the wheel cylinders 17 and 18.

The actuator 14 is a so-called ESC (electric stability control) actuator, and can adjust the hydraulic pressure of the wheel cylinders 15 to 18 individually. The actuator 14 performs various controls such as ABS (anti-lock braking system) control, anti-skid control, and traction control according to the control of the brake ECU 19.

The pressurizing section 11 has a part of the fluid paths 12 and 13, a master cylinder unit 21, an electric cylinder 22, a reservoir 23, a communication path 24, a brake fluid supply path 25, a communication control valve 26, and a master cut valve 27. The master cylinder unit 21 is an example of a vehicle brake fluid pressure generating device.

The master cylinder unit 21 has a master cylinder 31 and a pedal 32. The master cylinder 31 is connected to the reservoir 23 via a fluid path 33, and mechanically supplies brake fluid to the first hydraulic pressure output section 14a of the actuator 14 according to the amount of operation of the pedal 32.

The master cylinder unit 21 is configured to be able to pressurize the wheel cylinders 15, 16 through the first hydraulic output section 14a. The master cylinder unit 21 is provided with a stroke simulator 34 and a simulator cut valve 35. The stroke simulator 34 generates a reaction force (load) against the operation of the pedal 32. The simulator cut valve 35 is a normally closed solenoid valve.

The electric cylinder 22 is connected to a reservoir 23. The electric cylinder 22 adjusts the hydraulic pressure in the wheel cylinders 15 and 16 through the hydraulic passage 12, and adjusts the hydraulic pressure in the wheel cylinders 17 and 18 through the hydraulic passage 13. The electric cylinder 22 has a cylinder 22a, an electric motor 22b, a piston 22c, an output chamber 22d, and a biasing member 22e.

The electric motor 22b is connected to the piston 22c via a linear motion mechanism 22f that converts rotational motion into linear motion. The electric cylinder 22 is a single-type electric cylinder in which a single output chamber 22d is formed in the cylinder 22a.

The piston 22c slides in the cylinder 22a in the longitudinal direction (axial direction) of the cylinder 22a when driven by the electric motor 22b. The output chamber 22d is formed (defined, partitioned) by the cylinder 22a and the piston 22c, and the volume changes as the piston 22c moves. The output chamber 22d is connected to the reservoir 23 and the actuator 14. The output chamber 22d and the reservoir 23 are in communication when the piston 22c is in the initial position.

The fluid path 12 connects the master cylinder 31 and the first hydraulic pressure output section 14a. The fluid path 13 connects the electric cylinder 22 and the second hydraulic pressure output section 14b. The communication path 24 connects the fluid path 12 and the fluid path 13.

The communication control valve 26 is a normally closed solenoid valve provided in the communication passage 24. The communication control valve 26 permits or prohibits the electric cylinder 22 from supplying brake fluid to the first hydraulic output section 14a.

The master cut valve 27 is a normally open solenoid valve provided in the fluid path 12 between the connection 12a between the fluid path 12 and the communication path 24 and the master cylinder unit 21. The master cut valve 27 permits or prohibits the supply of brake fluid from the master cylinder unit 21 to the first hydraulic pressure output section 14a. The brake fluid supply path 25 connects the reservoir 23 and the electric cylinder 22. The reservoir 23 stores brake fluid and the internal pressure is kept at atmospheric pressure.

The pressurizing unit 11 further includes a stroke sensor 37 and pressure sensors 38 and 39. The stroke sensor 37 detects the stroke of the pedal 32. The pressure sensor 38 detects the hydraulic pressure (master pressure) of the master cylinder 31. The pressure sensor 39 detects the output hydraulic pressure of the electric cylinder 22.

The pressure applying unit 11 is configured to be capable of forming a by-wire configuration in which the hydraulic pressure generated by the operation of the pedal 32 and the hydraulic pressure generated by the control are hydraulically separated. For example, when the ignition is turned on or the vehicle 1 is started in an electric vehicle, the brake ECU 19 switches the pressure applying unit 11 to the by-wire mode.

In the by-wire mode, the communication control valve 26 is opened, the master cut valve 27 is closed, and the simulator cut valve 35 is opened. In the by-wire mode, the brake ECU 19 sets a target hydraulic braking force based on the target braking force and the actual regenerative braking force. The brake ECU 19 controls the electric cylinder 22 based on the target hydraulic braking force.

In this embodiment, the master cylinder unit 21 is disposed in the passenger compartment 1a of the vehicle 1. The passenger compartment 1a is a space in which the driver and passengers of the vehicle 1 sit, and in which, for example, a seat and a steering wheel are disposed. Meanwhile, the electric cylinder 22, the reservoir 23, the communication passage 24, the brake fluid supply passage 25, the communication control valve 26, the master cut valve 27, the stroke simulator 34, and the simulator cut valve 35 are housed in the engine room 1b of the vehicle 1. Note that the arrangement of the components of the pressurizing unit 11 is not limited to this example. For example, a part of the master cylinder 31 may be located in the engine room 1b. Also, the reservoir 23 may be disposed in the passenger compartment 1a.

Figure 2 is a perspective view showing the master cylinder unit 21 of the first embodiment. Figure 3 is a side view showing the master cylinder unit 21 of the first embodiment. Note that Figure 3 shows a cross-sectional view of a portion of the master cylinder unit 21. The master cylinder unit 21 has the master cylinder 31 and pedal 32 described above, as well as the base 41 and fixing device 42 shown in Figure 3.

As shown in each drawing, for the sake of convenience, an X-axis, a Y-axis, and a Z-axis are defined in this specification. The X-axis, the Y-axis, and the Z-axis are mutually perpendicular. The X-axis extends in the left-right direction of the vehicle 1. The Y-axis extends in the front-rear direction of the vehicle 1. The Z-axis extends in the up-down direction of the vehicle 1.

Furthermore, in this specification, the X direction, Y direction, and Z direction are defined. The X direction is a direction along the X axis, and includes the +X direction (right direction) indicated by the X axis arrow, and the -X direction (left direction) which is the opposite direction of the X axis arrow. The Y direction is a direction along the Y axis, and includes the +Y direction (forward direction) indicated by the Y axis arrow, and the -Y direction (backward direction) which is the opposite direction of the Y axis arrow. The Z direction is a direction along the Z axis, and includes the +Z direction (upward direction) indicated by the Z axis arrow, and the -Z direction (downward direction) which is the opposite direction of the Z axis arrow.

The base 41 is disposed on the floor surface 1c of the vehicle 1. In other words, the floor surface 1c faces the base 41. The floor surface 1c is provided on a floor panel of the body of the vehicle 1. Of the multiple surfaces formed by the floor panel, the floor surface 1c is a substantially flat surface that spreads along the X-Y plane and faces substantially in the +Z direction (upward). In front of this floor surface 1c, for example, a vehicle compartment partition wall portion (not shown) that extends substantially upward from the front end of the floor surface 1c and is generally called a dash panel (dash surface) is provided.

In this embodiment, the base 41 is supported on the floor surface 1c via the fixing device 42. In other words, the base 41 does not have to be in direct contact with the floor surface 1c. The base 41 may also be attached directly to the floor surface 1c.

The master cylinder 31 and pedal 32 are attached to the base 41. Therefore, the master cylinder unit 21 can be treated as a single modular component. The base 41 has a base plate 50, a first hinge 51, and a second hinge 52.

The base plate 50 is formed into a generally rectangular plate extending along the X-Y plane. The base plate 50 may be formed into other shapes. The base plate 50 has an upper surface 50a facing generally in the +Z direction and a lower surface 50b facing generally in the -Z direction. The upper surface 50a and the lower surface 50b are disposed generally parallel to the floor surface 1c. The lower surface 50b faces the floor surface 1c.

The first hinge 51 and the second hinge 52 are provided on the upper surface 50a of the base plate 50. The second hinge 52 is spaced apart from the first hinge 51 in the +Y direction. For example, the first hinge 51 is provided at the end of the base plate 50 in the -Y direction. Furthermore, the second hinge 52 is provided at the end of the base plate 50 in the +Y direction.

The fixing device 42 has a rail 55, a slider 56, and a stopper 57. The rail 55 is fixed to the floor surface 1c and extends approximately in the Y direction. The slider 56 is fixed to the lower surface 50b of the base plate 50. The slider 56 is held by the rail 55 so as to be movable in the Y direction relative to the floor surface 1c. In this way, the base 41 is attached to the floor surface 1c via the fixing device 42.

The stopper 57 is attached to the slider 56, for example. The stopper 57 restricts the movement of the slider 56 relative to the rail 55. The stopper 57 also releases the restriction on the movement of the slider 56 in response to, for example, the operation of the driver of the vehicle 1. The stopper 57 has various components, such as a claw, a spring, and a lever.

The fixing device 42 can releasably fix the master cylinder 31, the pedal 32, and the base 41 to the floor surface 1c. Therefore, the fixing device 42 can adjust the positions of the master cylinder 31, the pedal 32, and the base 41 in the Y direction. The fixing device 42 may fix the master cylinder 31, the pedal 32, and the base 41 to the floor surface 1c in such a way that the positions cannot be adjusted.

The master cylinder 31 has a housing 61, a piston 62, an upper connection portion 63, and a lower connection portion 64. The housing 61 may also be referred to as a cylinder. The upper connection portion 63 is an example of a first connection portion. The lower connection portion 64 is an example of a second connection portion.

The housing 61 is formed in a generally cylindrical shape with a bottom, and has a space 70 provided inside. The housing 61 may be formed in other shapes. The space 70 has a generally circular cross section and is a hole (recess) that opens at one end of the housing 61. The housing 61 has a first end face 71, a second end face 72, an outer peripheral surface 73, an inner peripheral surface 74, and a bottom surface 75.

The first end surface 71 is a generally circular flat surface provided at one end of the housing 61. The second end surface 72 is a generally circular flat surface provided at the other end of the housing 61. The space 70 is open at the first end surface 71 and closed at the second end surface 72.

The outer peripheral surface 73 is formed in a generally cylindrical shape and faces the outside of the housing 61. The inner peripheral surface 74 and the bottom surface 75 form (define, partition) the space 70. The inner peripheral surface 74 is located opposite the outer peripheral surface 73. The inner peripheral surface 74 is formed in a generally cylindrical shape and faces the inside of the space 70. The bottom surface 75 is a generally circular flat surface provided at the bottom of the space 70. In other words, the bottom surface 75 is spaced from the first end surface 71. The inner peripheral surface 74 is connected to the inner edge of the first end surface 71 and the outer edge of the bottom surface 75.

The space 70, the substantially circular first end face 71, the second end face 72, and the bottom face 75, and the substantially cylindrical outer peripheral face 73 and inner peripheral face 74 are arranged concentrically on the axis Axc. The axis Axc is the common center of the space 70, the first end face 71, the second end face 72, the outer peripheral face 73, the inner peripheral face 74, and the bottom face 75. Note that the center of at least one of the space 70, the first end face 71, the second end face 72, the outer peripheral face 73, the inner peripheral face 74, and the bottom face 75 may be offset from the axis Axc.

The first end face 71, the second end face 72, and the bottom face 75 face in the axial direction Da. The axial direction Da is a direction along the axis Axc. The axial direction Da includes one direction along the axis Axc and the opposite direction.

The housing 61 is provided with a supply port 77 and a discharge port 78. The supply port 77 and the discharge port 78 open to the outer peripheral surface 73 and the inner peripheral surface 74, respectively. Therefore, the supply port 77 and the discharge port 78 communicate the space 70 inside the housing 61 with the outside of the housing 61. The supply port 77 is closer to the first end face 71 than the discharge port 78. The supply port 77 and the discharge port 78 open substantially in the X direction. Note that the supply port 77 and the discharge port 78 may open in other directions.

The piston 62 is at least partially accommodated in the space 70 inside the housing 61. The piston 62 is formed in a generally cylindrical shape extending in the axial direction Da. The piston 62 may be formed in another shape that can be accommodated in the space 70. The piston 62 has an inner end surface 81, an outer end surface 82, and an outer circumferential surface 83.

The inner end surface 81 is a substantially circular flat surface provided at one end of the piston 62. The inner end surface 81 is located inside the space 70 and faces the bottom surface 75 of the housing 61. The outer end surface 82 is a substantially circular flat surface provided at the other end of the piston 62. The outer end surface 82 is located outside the space 70. The outer peripheral surface 83 is formed in a substantially cylindrical shape extending in the axial direction Da. The outer peripheral surface 83 is connected to the edge of the inner end surface 81 and the edge of the outer end surface 82.

The roughly circular inner end surface 81 and outer end surface 82 and the roughly cylindrical outer circumferential surface 83 are arranged concentrically on the axis Axc. That is, the inner circumferential surface 74 of the housing 61 and the outer circumferential surface 83 of the piston 62 are arranged concentrically. The inner end surface 81 and the outer end surface 82 face in the axial direction Da.

The outer peripheral surface 83 of the piston 62 is at least partially in contact with the inner peripheral surface 74 of the housing 61, or faces the inner peripheral surface 74 of the housing 61 with a small gap therebetween. Therefore, the piston 62 can reciprocate in the axial direction Da relative to the housing 61.

An oil chamber 70a is provided inside the housing 61. The oil chamber 70a is part of the space 70, and is formed (defined, partitioned) by, for example, the inner circumferential surface 74 and the bottom surface 75 of the housing 61 and the inner end surface 81 of the piston 62.

The supply port 77 and the discharge port 78 are connected to the oil chamber 70a. Depending on the position of the piston 62 relative to the housing 61, at least a portion of the supply port 77 and the discharge port 78 may be blocked by the piston 62.

Hydraulic oil is introduced into the oil chamber 70a. For example, the oil chamber 70a is connected to the reservoir 23 through a pipe of the fluid path 33 connected to the supply port 77. Furthermore, the oil chamber 70a is connected to the first hydraulic output section 14a, the master cut valve 27, and the simulator cut valve 35 through a pipe of the fluid path 12 connected to the discharge port 78.

The volume of the oil chamber 70a changes due to the relative movement of the housing 61 and the piston 62 in the axial direction Da. For example, as the piston 62 approaches the bottom surface 75, the volume of the oil chamber 70a decreases and the pressure of the hydraulic oil in the oil chamber 70a increases. For example, a seal is provided between the inner surface 74 of the housing 61 and the outer surface 83 of the piston 62. This prevents the hydraulic oil from leaking from the gap between the housing 61 and the piston 62.

The upper connection portion 63 is connected to the pedal 32. In this embodiment, the upper connection portion 63 is provided on the housing 61. In other words, the housing 61 is connected to the pedal 32 at the upper connection portion 63. The upper connection portion 63 protrudes, for example, from approximately the center of the second end surface 72 of the housing 61. The upper connection portion 63 may be provided on another part of the housing 61.

The lower connection portion 64 is connected to the second hinge 52 of the base 41. In this embodiment, the lower connection portion 64 is provided on the piston 62. In other words, the piston 62 is connected to the base 41 at the lower connection portion 64. The lower connection portion 64 protrudes from, for example, the outer end surface 82 of the piston 62. Note that the lower connection portion 64 may be provided on another portion of the piston 62.

The pedal 32 has a movable end 32a, a connecting end 32b, and an intermediate connecting portion 32c. The movable end 32a is an example of a first portion. The connecting end 32b is an example of a second portion. Note that the first portion and the second portion are not limited to the ends of the pedal 32.

The movable end 32a is provided at one end of the pedal 32. The connection end 32b is provided at the other end of the pedal 32. In other words, the connection end 32b is located on the opposite side of the movable end 32a and is spaced apart from the movable end 32a.

The connection end 32b is connected to the first hinge 51 of the base 41 so as to be rotatable around the first rotation axis Ax1. The first rotation axis Ax1 is an imaginary straight line that is the center of the rotational motion of the pedal 32.

For example, a substantially circular hole is provided in the connection end 32b. Furthermore, a substantially cylindrical protrusion that fits into the hole is provided in the first hinge 51. The first rotation axis Ax1 is the center of the hole and the protrusion. This allows the connection end 32b to be attached to the first hinge 51 so as to be rotatable around the first rotation axis Ax1. Note that the method of attaching the connection end 32b to the first hinge 51 is not limited to this example.

In this embodiment, the first rotation axis Ax1 extends substantially in the X direction. In other words, the first rotation axis Ax1 extends substantially parallel to the floor surface 1c. Therefore, when the pedal 32 rotates around the first rotation axis Ax1, the movable end 32a approaches or moves away from the floor surface 1c. The first rotation axis Ax1 may be inclined with respect to the floor surface 1c.

The pedal 32 is depressed by the driver of the vehicle 1. In response to the depression of the pedal 32, the pedal 32 rotates around a first rotation axis Ax1. In this embodiment, the rotational motion of the pedal 32 has one first rotation axis Ax1 and describes a circular orbit. However, the rotational motion of the pedal 32 may have multiple first rotation axes Ax1 and describe, for example, an elliptical orbit.

The pedal 32 in this embodiment is a so-called organ-type operating member. The first rotation axis Ax1 is provided at the connection end 32b located below the movable end 32a. The pedal 32 is depressed by the driver of the vehicle 1. Note that the pedal 32 is not limited to this example.

The intermediate connection part 32c is located between the movable end part 32a and the connection end part 32b. The upper connection part 63 of the master cylinder 31 is connected to the intermediate connection part 32c so as to be rotatable around the second rotation axis Ax2. The second rotation axis Ax2 is an imaginary straight line that is the center of the relative rotational movement between the master cylinder 31 and the pedal 32.

In this embodiment, the second rotation axis Ax2 extends substantially in the X direction. Therefore, the second rotation axis Ax2 extends substantially parallel to the first rotation axis Ax1 and substantially parallel to the floor surface 1c. The second rotation axis Ax2 may extend in another direction.

2, the pedal 32 has, for example, a pedal member 91, two side walls 92, and a shaft 93. Note that the pedal 32 is not limited to this example. For example, the pedal 32 may have an arm that supports the pedal member 91 at a position spaced apart from the floor surface 1c.

The pedal member 91 is formed in a generally plate-like shape. As shown in FIG. 3, the pedal member 91 has a receiving surface 91a and a back surface 91b. The receiving surface 91a and the back surface 91b are flat or curved surfaces that are generally parallel to the first rotation axis Ax1. Note that the receiving surface 91a and the back surface 91b are not limited to this example.

The receiving surface 91a supports the foot of the driver of the vehicle 1 and receives the load from the driver when the driver depresses the pedal. The back surface 91b is located on the opposite side of the receiving surface 91a. The back surface 91b faces the master cylinder 31.

The receiving surface 91a is formed, for example, by a pedal pad made of synthetic resin or metal. The back surface 91b is formed, for example, by a metal frame to which the pedal pad is attached. Note that the receiving surface 91a and the back surface 91b are not limited to this example.

A recess 91c is provided in the pedal member 91. The recess 91c is recessed from the back surface 91b. For example, a part of the housing 61 is accommodated in the recess 91c. The provision of the recess 91c prevents the pedal member 91 from coming into contact with the housing 61.

As shown in FIG. 2, the side walls 92 protrude from the rear surface 91b of the pedal member 91. The two side walls 92 are spaced apart from each other in the X direction. In the X direction, the master cylinder 31 is located between the two side walls 92.

The connection end 32b of the pedal 32 is provided on the side wall 92. For example, a number of substantially circular holes are provided in each of the two side walls 92. A protrusion of the first hinge 51 is fitted into one of the holes. This allows the connection end 32b to be attached to the first hinge 51 so as to be rotatable around the first rotation axis Ax1.

The shaft 93 is formed in a generally cylindrical shape extending generally in the X direction. The shaft 93 connects the side wall 92 and the upper connection portion 63 of the master cylinder 31. The shaft 93 is rotatable about a second rotation axis Ax2 relative to at least one of the side wall 92 and the upper connection portion 63. The second rotation axis Ax2 is the center of the shaft 93.

The intermediate connection part 32c of the pedal 32 is provided on the shaft 93. For example, the shaft 93 is fitted into one of the holes provided in the side wall 92. Furthermore, the shaft 93 is fitted into a substantially circular hole provided in the upper connection part 63. In this way, the intermediate connection part 32c is attached to the upper connection part 63 so as to be rotatable around the second rotation axis Ax2. Note that the method of connecting the intermediate connection part 32c and the upper connection part 63 is not limited to this example.

As shown in FIG. 3, the lower connection portion 64 of the master cylinder 31 is connected to the second hinge 52 of the base 41 so as to be rotatable about a third rotation axis Ax3. The third rotation axis Ax3 is an imaginary straight line that is the center of the rotational motion of the master cylinder 31.

In this embodiment, the third rotation axis Ax3 extends substantially in the X direction. Therefore, the third rotation axis Ax3 extends substantially parallel to the first rotation axis Ax1 and the second rotation axis Ax2, and also extends substantially parallel to the floor surface 1c. Note that the third rotation axis Ax3 may extend in another direction.

The first rotation axis Ax1, the second rotation axis Ax2, and the third rotation axis Ax3 are spaced apart from each other. In this embodiment, the distance between the first rotation axis Ax1 and the second rotation axis Ax2 is approximately constant. The distance between the first rotation axis Ax1 and the third rotation axis Ax3 is also approximately constant. On the other hand, the distance between the second rotation axis Ax2 and the third rotation axis Ax3 changes according to the rotation of the pedal 32 around the first rotation axis Ax1. Note that the distance between the first rotation axis Ax1 and the second rotation axis Ax2 and the distance between the first rotation axis Ax1 and the third rotation axis Ax3 may be variable.

An imaginary ray (half-line) Lh that extends from the second rotation axis Ax2 and passes through the third rotation axis Ax3 intersects with the floor surface 1c and the base 41. In other words, the half-line Lh penetrates the floor surface 1c and the base 41. The half-line Lh is an imaginary line that extends from the second rotation axis Ax2 in a direction perpendicular to the second rotation axis Ax2. The half-line Lh passes through the third rotation axis Ax3 and extends infinitely. In other words, the half-line Lh includes a line segment that extends between the second rotation axis Ax2 and the third rotation axis Ax3, and an extension of the line segment that extends from the third rotation axis Ax3.

Since the second rotation axis Ax2 and the third rotation axis Ax3 extend approximately parallel to the X direction, multiple half lines Lh can exist in the X direction. The second rotation axis Ax2 and the third rotation axis Ax3 are arranged such that at least one of the multiple half lines Lh intersects with the floor surface 1c and the base 41.

In this embodiment, one half line Lh partially coincides with the axis Axc. Therefore, in this embodiment, the axis Axc also intersects with the floor surface 1c and the base 41. Note that the half line Lh and the axis Axc do not have to coincide.

By arranging the second rotation axis Ax2 and the third rotation axis Ax3 as described above, the bottom surface 75 of the housing 61 faces the floor surface 1c and the base 41. Furthermore, the outer end surface 82 of the piston 62 also faces the floor surface 1c and the base 41.

Figure 4 is a side view showing the positions of the first rotation axis Ax1, the second rotation axis Ax2, and the third rotation axis Ax3 of the first embodiment. As shown in Figure 4, when viewed in the X direction, the angle θ1 between the imaginary straight line Ls extending between the first rotation axis Ax1 and the second rotation axis Ax2 and the half line Lh is set to be greater than 0° and less than 90°.

In this embodiment, the angle θ1 between the line Ls and the half line Lh is set to be greater than 0° and equal to or less than 45°. In other words, the line Ls and the half line Lh intersect at an acute angle. In other words, the angle θ1 is smaller than the angle θ2 between the half line Lh and the perpendicular line Lo that is perpendicular to the second rotation axis Ax2 and perpendicular to the line Ls. Note that the angle θ1 is not limited to this example.

In this embodiment, the distance _D13 between the first rotation axis Ax1 and the third rotation axis Ax3 is shorter than the distance _D12 between the first rotation axis Ax1 and the second rotation axis Ax2. Note that the distance _D13 may be equal to or longer than the distance _D12 .

In the initial position where the pedal 32 is not depressed, the distance _DY13 between the first rotation axis Ax1 and the third rotation axis Ax3 in the Y direction is shorter than the distance _DY12 between the first rotation axis Ax1 and the second rotation axis Ax2 in the Y direction. Therefore, the third rotation axis Ax3 is located between the first rotation axis Ax1 and the second rotation axis Ax2 in the Y direction. Note that the distance _DY13 may be the same as or longer than the distance _DY12 .

As shown in FIG. 3, in the initial position, the length of the base 41 in the Y direction is shorter than the length of the pedal 32 in the Y direction. Furthermore, as shown in FIG. 2, in the initial position, the length of the base 41 in the X direction is shorter than the length of the pedal 32 in the X direction.

As shown in FIG. 3, in the Y direction, the entire master cylinder 31 is located between the movable end 32a and the connecting end 32b of the pedal 32. Furthermore, as shown in FIG. 2, in the X direction, the entire master cylinder 31 is located between the two side walls 92 of the pedal 32.

The entire master cylinder 31 is covered by the pedal 32 in the Z direction. The Z direction is a direction perpendicular to the floor surface 1c. That is, when viewed in the Z direction, the entire master cylinder 31 overlaps with the pedal 32. In other words, the entire master cylinder 31 fits within the area where the pedal 32 is projected in the Z direction. Note that the master cylinder 31 is not limited to this example.

As described above, the pedal 32 is depressed by the driver of the vehicle 1. Specifically, the pedal 32 is pushed by the driver's foot in approximately the +Y direction. The direction of the force received by the pedal 32 includes a component in the direction of rotation (circumferential direction) around the first rotation axis Ax1. Therefore, when the pedal 32 is depressed, it rotates around the first rotation axis Ax1 so that the movable end 32a approaches the floor surface 1c.

When the movable end 32a approaches the floor surface 1c, the intermediate connection part 32c pushes the housing 61 and the upper connection part 63 of the master cylinder 31 in the axial direction Da along the axis Axc (semi-line Lh). The force acting on the housing 61 acts on the piston 62 and the base 41, for example, via the hydraulic oil in the oil chamber 70a.

As described above, the half line Lh intersects with the floor surface 1c and the base 41. Therefore, the force input from the pedal 32 to the master cylinder 31 and the force input from the master cylinder 31 to the base 41 are forces in the direction from the second rotation axis Ax2 toward the floor surface 1c.

When the intermediate connection part 32c presses against the housing 61, the bottom surface 75 of the housing 61 and the inner end surface 81 of the piston 62 approach each other. This reduces the volume of the oil chamber 70a, and the hydraulic pressure in the oil chamber 70a increases.

While the pedal 32 rotates around the first rotation axis Ax1, the master cylinder 31 rotates around the second rotation axis Ax2 relative to the pedal 32 and also rotates around the third rotation axis Ax3 relative to the base 41. That is, the master cylinder 31 rotates in conjunction with the rotation of the pedal 32. This makes it possible for the master cylinder 31 to suppress interference with the rotation of the pedal 32.

When the driver releases the pedal 32, the hydraulic pressure in the oil chamber 70a presses against the bottom surface 75 of the housing 61 and the inner end surface 81 of the piston 62. This causes the pedal 32 to rotate around the first rotation axis Ax1 so that the intermediate connection part 32c moves away from the base 41, and returns to the initial position.

4, a force Fi input to the pedal 32 by the driver of the vehicle 1 depressing the pedal 32 is amplified by a pedal ratio R that can be expressed by the following equation (Equation 1), and is input as a force Fo to the master cylinder unit 21. In equation (Equation 1), Dp is the distance between the first rotation axis Ax1 and the position Pi at which the force Fi is input to the pedal 32.
R = (Dp/ _D12 )/sin θ1 ... (Equation 1)

The formula (1) shows the pedal ratio R in the initial position where the pedal 32 is not depressed. As the pedal 32 rotates around the first rotation axis Ax1 by depressing the pedal, the angle θ1 decreases and the pedal ratio R increases. Note that, according to the arrangement of the first rotation axis Ax1, the second rotation axis Ax2, and the third rotation axis Ax3 in this embodiment, the variation in the angle θ1 during the depressing operation is small.

The pedal ratio R may be expressed by a formula other than formula (1). For example, as the pedal 32 rotates around the first rotation axis Ax1, the angle θ3 between the Z axis and the straight line Ls increases. The angle θ1 and the pedal ratio R with the angle θ1 as a variable can be expressed by a function with the angle θ3 as a variable. Note that, for convenience of explanation, the position Pi is an input point to the pedal 32 set on the straight line Ls, and is not necessarily the position of the actual input point when the driver depresses the pedal.

In this embodiment, the angle θ1 is set to be greater than 0° and equal to or less than 45°. The smaller the angle θ1, the smaller the sin θ1 in equation (1) becomes, and the larger the pedal ratio R becomes. This allows the brake device 10 to obtain the desired hydraulic pressure in the oil chamber 70a of the master cylinder 31 from a smaller force Fi.

In the brake device 10 according to the first embodiment described above, the pedal 32 has a movable end 32a and a connection end 32b separated from the movable end 32a. The connection end 32b is connected to the base 41 so as to be rotatable around the first rotation axis Ax1. When the pedal 32 rotates around the first rotation axis Ax1, the movable end 32a approaches or moves away from the floor surface 1c. The master cylinder 31 has a housing 61, a piston 62, an upper connection portion 63, and a lower connection portion 64. The upper connection portion 63 is provided on one of the housing 61 and the piston 62, and is connected to the pedal 32 so as to be rotatable around the second rotation axis Ax2. The lower connection portion 64 is provided on the other of the housing 61 and the piston 62, and is connected to the base 41 so as to be rotatable around the third rotation axis Ax3. A virtual half line Lh extending from the second rotation axis Ax2 and passing through the third rotation axis Ax3 intersects with the floor surface 1c. As a result, the distance DY13 between the first rotation axis Ax1 and the third rotation axis Ax3 in the front-rear direction (Y direction) of the vehicle 1 along the floor surface 1c is shorter than in the case where the half line _Lh extends substantially parallel to the floor surface 1c. Therefore, the master cylinder unit 21 can shorten the length of the base 41 in the front-rear direction of the vehicle 1. Therefore, the master cylinder unit 21 of this embodiment can be made smaller in size in the front-rear direction of the vehicle 1, and thus the degree of freedom in arrangement can be improved.

Furthermore, the master cylinder unit 21 of this embodiment amplifies the force Fi input by the driver to the pedal 32 by a pedal ratio R approximately expressed by the formula (Equation 1) and inputs it to the master cylinder 31. In this embodiment, the master cylinder 31 is positioned so that the half line Lh intersects with the floor surface 1c. This positioning of the master cylinder 31 allows the angle θ1 to be reduced, and thus the pedal ratio R to be increased. Therefore, the master cylinder unit 21 of this embodiment makes it easier to obtain the desired pedal ratio R while reducing the size of the vehicle 1 in the fore-aft direction.

The angle θ1 between the imaginary straight line Ls extending between the first rotation axis Ax1 and the second rotation axis Ax2 and the half line Lh is greater than 0° and equal to or less than 45°. This suitably shortens the distance _DY13 between the first rotation axis Ax1 and the third rotation axis Ax3 in the longitudinal direction of the vehicle 1. Furthermore, since the angle θ1 is an acute angle (more specifically, an acute angle of 45° or less among "acute angles" that are angles less than a right angle), the pedal ratio R is suitably increased. Therefore, the master cylinder unit 21 of this embodiment can easily obtain a desired pedal ratio R while being miniaturized in the longitudinal direction of the vehicle 1. In addition, the master cylinder 31 can suppress the axis center Axc from facing the driver, thereby improving safety in the event of a collision of the vehicle 1.

The upper connection part 63 is provided on the housing 61. The lower connection part 64 is provided on the piston 62. In other words, the housing 61 is connected to the pedal 32, and the piston 62 is connected to the base 41. This positions the housing 61 above the piston 62. The tubes of the fluid paths 12 and 33 are generally connected to the housing 61. When hydraulic oil and air are mixed in the oil chamber 70a, the air rises upward. In this embodiment, since the housing 61 is located above the piston 62, for example, when replacing the hydraulic oil in the oil chamber 70a, the air that has risen is easily discharged through the tube of the fluid path 12.

The entire master cylinder 31 is covered by the pedal 32 in the Z direction perpendicular to the floor surface 1c. This allows the master cylinder unit 21 of this embodiment to be made smaller in size in the front-rear direction of the vehicle 1, thereby improving the freedom of placement. Furthermore, the pedal 32 can protect the master cylinder 31.

A distance _D13 between the first rotation axis Ax1 and the third rotation axis Ax3 is shorter than a distance _D12 between the first rotation axis Ax1 and the second rotation axis Ax2. This allows the master cylinder unit 21 of this embodiment to be suitably miniaturized in the front-rear direction of the vehicle 1, and thus allows the degree of freedom in arrangement to be suitably improved.

Second Embodiment
The second embodiment will be described below with reference to Figures 5 and 6. In the following description of the embodiment, components having the same functions as components already described are given the same reference numerals as the components already described, and further description may be omitted. In addition, multiple components given the same reference numerals do not necessarily have all the same functions and properties, and may have different functions and properties according to each embodiment.

Figure 5 is a perspective view showing the master cylinder unit 21 according to the second embodiment. Figure 6 is a side view showing the master cylinder unit 21 according to the second embodiment. Note that Figure 6 shows a cross-sectional view of a portion of the master cylinder unit 21.

As shown in FIG. 6, in the master cylinder unit 21 of the second embodiment, the master cylinder 31 has a housing 101, a piston 102, an upper connection portion 103, and a lower connection portion 104. The housing 101 may also be referred to as a cylinder. The upper connection portion 103 is an example of a first connection portion. The lower connection portion 104 is an example of a second connection portion.

The housing 101 has approximately the same shape as the housing 61 of the first embodiment. That is, the housing 101 has a space 70 therein and has a first end face 71, a second end face 72, an outer peripheral surface 73, an inner peripheral surface 74, and a bottom surface 75. The housing 101 is disposed in the opposite direction to the housing 61 of the first embodiment. Therefore, the second end face 72 of the housing 101 faces the floor surface 1c and the base 41.

The piston 102 has substantially the same shape as the piston 62 of the first embodiment. That is, the piston 102 is at least partially accommodated in the space 70 inside the housing 101, and has an inner end surface 81, an outer end surface 82, and an outer peripheral surface 83. The piston 102 is disposed in the opposite direction to the piston 62 of the first embodiment. Therefore, the inner end surface 81 of the piston 102 faces the floor surface 1c and the pedestal 41.

The upper connection part 103 is connected to the intermediate connection part 32c of the pedal 32 so as to be rotatable around the second rotation axis Ax2. In this embodiment, the upper connection part 103 is provided on the piston 102. In other words, the piston 102 is connected to the intermediate connection part 32c of the pedal 32 at the upper connection part 103. The upper connection part 103 protrudes from, for example, the outer end surface 82 of the piston 102.

The lower connection part 104 is connected to the second hinge 52 of the base 41 so as to be rotatable around the third rotation axis Ax3. In this embodiment, the lower connection part 104 is provided on the housing 101. In other words, the housing 101 is connected to the base 41 at the lower connection part 104. The lower connection part 104 protrudes from, for example, the second end surface 72 of the housing 101.

In the brake device 10 of the second embodiment described above, the upper connection part 103 is provided on the piston 102, and the lower connection part 104 is provided on the housing 101. In other words, the piston 102 is connected to the pedal 32, and the housing 101 is connected to the base 41. This makes the housing 101 closer to the first rotation axis Ax1 and the third rotation axis Ax3 than the piston 102. With this arrangement, when the pedal 32 rotates around the first rotation axis Ax1, the movement distance of the housing 101 is shorter than the movement distance of the piston 102. The pipes of the fluid paths 12 and 33 are generally connected to the housing 61. Therefore, the brake device 10 of the second embodiment can reduce the vibration width of the pipes of the fluid paths 12 and 33 when the pedal 32 rotates around the first rotation axis Ax1, compared to the first embodiment.

The vehicle brake fluid pressure generating device according to at least one embodiment described above includes, as an example, a base, a pedal, and a master cylinder. The base is attached to a floor surface of a vehicle. The pedal has a first portion and a second portion that is separated from the first portion and connected to the base so as to be rotatable around a first rotation axis, and the first portion approaches or moves away from the floor surface by rotating around the first rotation axis. The master cylinder has a housing, a piston that is at least partially accommodated in the housing and can reciprocate relative to the housing, a first connection portion that is provided on one of the housing and the piston and is connected to the pedal so as to be rotatable around a second rotation axis, and a second connection portion that is provided on the other of the housing and the piston and is connected to the base so as to be rotatable around a third rotation axis, and an imaginary half line extending from the second rotation axis and passing through the third rotation axis intersects with the floor surface. Therefore, as an example, the distance between the first rotation axis and the third rotation axis in the front-rear direction of the vehicle along the floor surface is shorter than when the half line extends approximately parallel to the floor surface. Therefore, the vehicle brake fluid pressure generating device can be made smaller in size in the front-rear direction of the vehicle.

In the above-mentioned vehicle brake fluid pressure generating device, as one example, the angle between the half line and an imaginary line extending between the first rotation shaft and the second rotation shaft is greater than 0° and less than or equal to 45°. Therefore, as one example, the distance between the first rotation shaft and the third rotation shaft in the longitudinal direction of the vehicle is suitably shortened. This allows the vehicle brake fluid pressure generating device to be suitably miniaturized in the longitudinal direction of the vehicle.

In the vehicle brake fluid pressure generating device, as one example, the first connection part is provided on the housing, and the second connection part is provided on the piston. Therefore, as one example, since the housing is located above the piston, air that rises inside the housing can be easily discharged through a tube connected to the housing.

In the above-mentioned vehicle brake fluid pressure generating device, as one example, the entire master cylinder is covered by the pedal in a direction perpendicular to the floor surface. Therefore, as one example, the vehicle brake fluid pressure generating device can be made smaller in size in the front-rear direction of the vehicle.

In the above-mentioned vehicle brake fluid pressure generating device, as an example, the distance between the first rotating shaft and the third rotating shaft is shorter than the distance between the first rotating shaft and the second rotating shaft. Therefore, as an example, the vehicle brake fluid pressure generating device can be suitably miniaturized in the front-rear direction of the vehicle.

The vehicle brake device according to at least one embodiment described above includes, as an example, the vehicle brake fluid pressure generating device. Therefore, as an example, the vehicle brake device can reduce the size of the vehicle brake fluid pressure generating device in the front-rear direction of the vehicle.

In the above explanation, suppression is defined as, for example, preventing the occurrence of an event, action, or effect, or reducing the severity of an event, action, or effect. In the above explanation, restriction is defined as, for example, preventing movement or rotation, or allowing movement or rotation within a specified range and preventing movement or rotation beyond the specified range.

Although the above describes the embodiments of the present invention, the above embodiments and variations are merely examples and are not intended to limit the scope of the invention. The above embodiments and variations can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. In addition, the configurations and shapes of each embodiment and each variation can be partially interchanged.

1...vehicle, 1c...floor surface, 10...brake device (vehicle brake device), 21...master cylinder unit (vehicle brake fluid pressure generating device), 31...master cylinder, 32...pedal, 32a...movable end (first part), 32b...connection end (second part), 41...base, 61, 101...housing, 62, 102...piston, 63, 103...upper connection part (first connection part), 64, 104...lower connection part (second connection part), Ax1...first rotation axis, Ax2...second rotation axis, Ax3...third rotation axis, Lh...half line, Ls...line, θ1...angle, _D12 , _D13 ...distance.

Claims (6)

A base that is attached to a floor surface of a vehicle;
a pedal having a first portion and a second portion spaced apart from the first portion and connected to the base so as to be rotatable about a first rotation axis, the first portion moving closer to or further away from the floor surface by rotating about the first rotation axis;
a master cylinder having a housing, a piston at least partially accommodated in the housing and reciprocating relative to the housing, a first connection portion provided on one of the housing and the piston and connected to the pedal rotatably about a second rotation axis, and a second connection portion provided on the other of the housing and the piston and connected to the base rotatably about a third rotation axis, wherein an imaginary half line extending from the second rotation axis and passing through the third rotation axis intersects with the floor surface;
A vehicle brake fluid pressure generating device comprising: The vehicle brake fluid pressure generating device of claim 1, wherein the angle between the imaginary line extending between the first rotation shaft and the second rotation shaft and the half line is greater than 0° and less than or equal to 45°. The first connection portion is provided on the housing,
The second connection portion is provided on the piston.
3. A vehicle brake fluid pressure generating device according to claim 1 or 2. A brake fluid pressure generating device for a vehicle according to any one of claims 1 to 3, wherein the entire master cylinder is covered by the pedal in a direction perpendicular to the floor surface. A brake fluid pressure generating device for a vehicle according to any one of claims 1 to 4, wherein the distance between the first rotating shaft and the third rotating shaft is shorter than the distance between the first rotating shaft and the second rotating shaft. A vehicle brake system comprising a vehicle brake fluid pressure generating device according to any one of claims 1 to 5.

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