Brake fluid pressure control device and saddle-ride vehicle

Abstract

The present invention provides a brake fluid pressure control device that can lower the torque required to drive a pump in a drive state of a motor. A pump 27 of a brake fluid pressure control device 10 for controlling the brake fluid pressure of a brake system 100 installed in a motorcycle 1 comprises a plunger 27e that reciprocates inside a cylinder 27a as a result of being depressed by an eccentric body 52, wherein, in a drive state of the pump 27, the eccentric body 52 receives a reaction force of the plunger 27e from only one directional side or from non-opposing directional sides, and the center of an end part 51c of a first region 51a of an output shaft 51 is located farther away from the plunger 27e than the center of a second region 51b of the output shaft 51 between two bearings 50b, 50c.

Description

[0001] [Document name] Statement

[0002] [Title of invention] Brake fluid pressure control device and saddle-type vehicle

[0003] [Technical Field]

[0004]

[001] The present invention relates to a brake fluid pressure control device that controls the hydraulic pressure of brake fluid in a saddle-ride type vehicle, and to a saddle-ride type vehicle equipped with the brake fluid pressure control device.

[0005] [Background technology]

[0006]

[002] Conventionally, some straddle-type vehicles (e.g., motorcycles, etc.) are equipped with brake fluid pressure control devices that control the hydraulic pressure of brake fluid in a brake system that brakes the wheels. One such brake fluid pressure control device is, for example, one that is driven by an electric motor and includes a pump that pressure-feeds brake fluid (see, for example, Patent Document 1).

[0007] [Prior art documents]

[0008] [Patent documents]

[0009]

〇 0 0 3

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2023-131756

[0011] Summary of the Invention

[0012] [Problem to be solved by the invention]

[0013]

[0004] A brake fluid pressure control device such as that described in Patent Document 1 includes a pump driven by an electric motor. When power is applied to the electric motor, the electric motor generates heat, causing its temperature to rise. As the temperature of the magnets included in the electric motor rises, the magnetic flux density tends to decrease, and the output torque of the electric motor decreases as the temperature of the electric motor increases. When the electric motor is in a driven state, the increase in temperature can cause the output torque of the electric motor to fall below the torque required to continue driving the pump. In such a case, the pump stops rotating, which could make it difficult for the brake fluid pressure control device to control the brake fluid pressure.

[0014]

[0005] The present invention has been made against the background of the above-mentioned problems, and aims to provide a brake fluid pressure control device that can reduce the torque required to drive the pump when the motor is driven.

[0015] [Means for solving the problem]

[0016]

[0006] A brake fluid pressure control device according to the present invention is a brake fluid pressure control device that controls the hydraulic pressure of brake fluid in a brake system mounted on a saddle-ride type vehicle, and comprises: a base in which a fluid path for the brake fluid is formed; a pump that pumps the brake fluid in the fluid path; and an electric motor that is erected on the base and drives the pump; the electric motor comprises: a motor main body, an output shaft that is rotationally driven by the motor main body, two bearings that are provided on the motor main body and hold the output shaft by an interference fit, and an eccentric that is provided in a first region that protrudes from one bearing on the output shaft to the side opposite to the other bearing, and that rotates eccentrically with respect to the center of rotation of the output shaft; the pump comprises: a plunger that is pressed by the eccentric and moves reciprocally inside a cylinder; and a spring that presses the plunger toward the eccentric, and the plunger is pressed against one side of the eccentric. When the pump is in a driven state, the eccentric receives a reaction force from the plunger only from one side or from the opposite sides, and the center of the end of the first region of the output shaft is located farther from the plunger pressed by the eccentric than the center of the second region between the two bearings on the output shaft.

[0017] [0 0 0 7] With this configuration, when the pump is in a driven state, the eccentric receives the reaction force of the plunger only from one side or from sides that do not face each other, and the center of the end of the first region of the output shaft that protrudes from one bearing of the motor main body to the side opposite the other bearing is located farther from the plunger pressed by the eccentric than the center of the second region between the two bearings on the output shaft. Therefore, the stroke length in the reciprocating motion of the plunger can be shortened by the distance between the center of the end of the first region of the output shaft and the center of the second region, and the torque required to drive the pump can be reduced.

[0018]

[0008] A straddle-type vehicle according to the present invention is configured to include the above-described brake fluid pressure control device. With this configuration, the straddle-type vehicle can achieve the same effects as the above-described brake fluid pressure control device.

[0019] 〇

[0020]

[0009] The present invention may have only the matters specifying the invention as set forth in the claims, or may have both the matters specifying the invention and other features.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [ 0 0 1 0 ]

[0023] [Fig. 1] A diagram for explaining a motorcycle on which a brake fluid pressure control device according to an embodiment is mounted.

[0024] [Figure 2] A diagram for explaining the brake system of a motorcycle controlled by a brake fluid pressure control device.

[0025] [Figure 3] A diagram for explaining the brake fluid pressure control device.

[0026] [Figure 4] A diagram for explaining the pump of the brake fluid pressure control device.

[0027] [Figure 5] A diagram for explaining the motor of the brake fluid pressure control device.

[0028] [Figure 6] A diagram for explaining a modified example of the motor of the brake fluid pressure control device.

[0029] [Mode for Carrying Out the Invention]

[0030]

[0011] Examples of embodiments of a brake fluid pressure control device according to the present invention and a saddle-type vehicle equipped with the brake fluid pressure control device will be described with reference to the drawings. In the embodiments, an example will be described in which the brake fluid pressure control device is mounted on a motorcycle as a saddle-type vehicle, but the brake fluid pressure control device according to the present invention may be mounted on saddle-type vehicles other than motorcycles. A "saddle-type vehicle" refers to any vehicle on which a rider straddles and rides. Examples of saddle-type vehicles include motorcycles, buggies, and bicycles. Motorcycles include motorbikes, motor tricycles, and the like that use an engine or an electric motor as a propulsion source, and include, for example, motorcycles, scooters, and electric scooters. A "bicycle" refers to any vehicle that can be propelled by the rider's pedaling force applied to the pedals. Examples of bicycles include standard bicycles, electrically assisted bicycles, and electric bicycles.

[0031]

[0012] In addition, in the embodiment, an example of a configuration in which the brake fluid pressure control device has a single fluid pressure circuit and a single pump is described, but the brake fluid pressure control device may have a configuration in which two or more fluid pressure circuits are provided, or a configuration in which two or more pumps are provided. In addition, in the embodiment, a case in which the brake fluid pressure control device is applied to a brake system that brakes the front wheel of a motorcycle is described, but the brake fluid pressure control device may be applied to a brake system that brakes both the front wheel and the rear wheel, or may be applied to a brake system that brakes only the rear wheel.

[0032]

[0013] Furthermore, the configurations, operations, etc. of the brake fluid pressure control device described in the embodiments are merely examples, and the brake fluid pressure control device according to the present invention is not limited to such configurations, operations, etc. Furthermore, in each drawing, the same or similar members or parts may be denoted by the same reference numerals or may not be denoted by the reference numerals. Furthermore, illustrations of detailed structures may be simplified or omitted as appropriate.

[0033] [ 0 0 1 4 ]

[0034] <Embodiment> A brake fluid pressure control device according to this embodiment will be described below with reference to Figs. 1 to 6. Fig. 1 is a diagram illustrating a motorcycle on which the brake fluid pressure control device of this embodiment is mounted. Fig. 2 is a diagram illustrating a brake system controlled by the brake fluid pressure control device. Fig. 3 is a diagram illustrating the brake fluid pressure control device. Fig. 4 is a diagram illustrating a pump provided in the brake fluid pressure control device. Fig. 5 is a diagram illustrating a motor provided in the brake fluid pressure control device. Fig. 6 is a diagram illustrating a modified example of the motor provided in the brake fluid pressure control device.

[0035] [ 0 0 1 5 ]

[0036] <Regarding the saddle-type vehicle and brake system> The motorcycle 1 as a saddle-type vehicle equipped with the brake fluid pressure control device 100, and the brake system 100 of the motorcycle 1 controlled by the brake fluid pressure control device 100 will be described with reference to Figures 1 and 2.

[0037]

[0016] As shown in FIG. 1, a motorcycle 1 includes a body 2, a handlebar 3 rotatably mounted on the body 2, a front wheel 4 rotatably mounted on the body 2 together with the handlebar 3, a rear wheel 5 rotatably mounted on the body 2 and driven by a drive source (not shown, for example, an engine or an electric motor), a front wheel disc rotor 4a that rotates together with the front wheel 4, a brake system 100 that brakes the front wheel 4, and a brake fluid pressure control device 10 that controls the brake system 100.

[0038]

[0017] As shown in FIG. 2, the brake system 100 includes an operator 6 operated by a rider, a front wheel braking mechanism 20 that brakes the front wheel 4, a front wheel friction member 25 that generates a friction force on the front wheel disc rotor 4a, and a brake fluid pressure control device 10.

[0039] In this embodiment, the operating element 6 is, for example, a brake lever provided on the handlebar 3 and operated by the rider's hand. Alternatively, the operating element 6 may be, for example, a brake pedal 7 provided on the lower part of the body 2 and operated by the rider's foot.

[0040]

[0019] As shown in Fig. 2, the front wheel braking mechanism 20 is composed of a master cylinder 21 to which the movement of an operator 6 is transmitted, a brake fluid reservoir 22 attached to the master cylinder 21, a wheel cylinder 24 connected to the master cylinder 21 via a fluid passage 23 filled with brake fluid, a front wheel friction member 25 pressed against a front wheel disc rotor 4a by the hydraulic pressure of the brake fluid in the wheel cylinder 24, and a brake fluid pressure control device 10 described below. As described below, parts 23b and 23c of the fluid passage 23 are formed as internal fluid passages in a base 60 of the brake fluid pressure control device 10. The brake fluid pressure control device 10 is disposed, for example, in the body 2 of the motorcycle 1 (see Fig. 1).

[0041]

[0020] The front wheel braking mechanism 20 is configured to press the front wheel friction member 25 against the front wheel disc rotor 4a in accordance with the amount of operation of the operator 6 to generate a friction force, thereby generating a braking force on the front wheel 4 in accordance with the amount of operation of the operator 6.

[0042]

[0021] In this embodiment, the front wheel braking mechanism 20 is configured to generate frictional force by pressing a friction member against the disc rotor. However, the front wheel braking mechanism may be configured, for example, to generate frictional force by pressing a friction member of a brake shoe against a brake drum that rotates together with the wheel, or may be configured, for example, to generate frictional force by pressing a friction member against the disc rotor or brake drum using an actuator that is electrically connected to an operator and is operated in response to the operation of the operator.

[0043] [ 0 0 2 2 ]

[0044] <Regarding the Brake Fluid Pressure Control Device> The brake fluid pressure control device 10 will be described with reference to Figures 2 to 6. The brake fluid pressure control device 10 includes first and second solenoid valves 40a, 40b, a pump 27, and a motor 50 as a fluid pressure control mechanism that controls the fluid pressure of the brake fluid in the brake system 100. The first and second solenoid valves 40a, 40b and the motor 50 that serve as the fluid pressure control mechanism are controlled by a control board 70 to be in an energized or de-energized state, and by controlling their operation, the fluid pressure of the brake fluid in the brake system 100 is controlled. The brake fluid pressure control device 10 can control the anti-lock operation of the front wheel 4 of the motorcycle 1 by controlling the operation of the fluid pressure control mechanism with the control board 70.

[0045]

[0023] As shown in FIG. 2, the brake fluid pressure control device 10 includes a main fluid path 23b connecting a master cylinder 21 and a wheel cylinder 24, a first solenoid valve 40a arranged in the main fluid path 23b, a sub-fluid path 23c branching from a region of the main fluid path 23b closer to the wheel cylinder 24 than the first solenoid valve 40a and connected to a region of the main fluid path 23b closer to the master cylinder 21 than the first solenoid valve 40a, a second solenoid valve 40b arranged in the sub-fluid path 23c, and an accumulator 26 arranged in a region of the sub-fluid path 23c closer to the master cylinder 21 than the second solenoid valve 40b and for temporarily storing brake fluid. and a pump 27 arranged in an area of ​​the sub-fluid path 23c closer to the master cylinder 21 than the accumulator 26. The main fluid path 23b and the sub-fluid path 23c constitute a part of the fluid path 23 described above.

[0046]

[0024] The first and second solenoid valves 40a and 40b have their corresponding first and second coils (not shown) controlled by the control board 70 to be energized or de-energized, and the operation of the first and second valve bodies (not shown) corresponding to each coil is controlled so that each liquid path is opened or closed.

[0047]

[0025] The pump 27 is driven by an electric motor 50 and pumps up the brake fluid stored in the accumulator 26 and outputs it toward the main fluid path 23b. The motor 50 has its operation (stopped state and rotating state) controlled by a control board 70, which controls its energized and de-energized state. Hereinafter, the first and second solenoid valves 40a, 40b, the pump 27, and the motor 50 may be referred to as a fluid pressure control mechanism that controls the fluid pressure of the brake fluid.

[0048]

[0026] The control board 70 of the brake fluid pressure control device 10 is equipped with a controller (not shown), which controls the fluid pressure control mechanisms 40a, 40b, 27, 50, etc. by executing predetermined programs, etc. The controller may be a single unit, or may be divided into multiple units. Some or all of the controller may be composed of, for example, a microcomputer, microprocessor unit, etc., or may be configured to be updatable by software such as firmware, or may be a program module executed by commands from a CPU, etc. Furthermore, the controllers may be provided on a single control board 70, or may be provided on multiple control boards.

[0049]

[0027] The controller also includes an acquisition unit (not shown) that acquires the detection results of various sensors (for example, a hydraulic pressure sensor that detects the hydraulic pressure of the brake fluid, a wheel speed sensor that detects the rotational speed of the wheels, an acceleration sensor that detects the acceleration in the roll, pitch, and yaw directions of the motorcycle 1, etc.), and an execution unit (not shown) that controls the operation of the brake system 100 (for example, normal operation, pressure reduction operation, etc., which will be described later) based on the various information acquired by the acquisition unit.

[0050]

[0028] For example, during normal operation, the control board 70 controls the first solenoid valve 40a to an open state and the second solenoid valve 40b to a closed state. When the rider operates the operator 6 in this state, the piston (not shown) of the master cylinder 21 is pressed in accordance with the amount of operation of the operator 6, increasing the hydraulic pressure of the brake fluid in the master cylinder 21. The increased hydraulic pressure is supplied to the wheel cylinder 24 via the main hydraulic path 23b, increasing the hydraulic pressure of the brake fluid in the wheel cylinder 24. The front wheel friction member 25 is then pressed against the front wheel disc rotor 4a in accordance with the hydraulic pressure in the wheel cylinder 24, generating a frictional force and braking the front wheel 4.

[0051]

[0029] Furthermore, for example, as control of antilock brake operation of the front wheels, when it is determined based on the detection results of various sensors that the rotation of the front wheels 4 is locked or there is a possibility that the rotation of the front wheels 4 may lock, the control board 70 executes a pressure reducing operation to reduce the hydraulic pressure of the brake fluid in the wheel cylinder 24. During the pressure reducing operation of the wheel cylinder 24, the controller controls the first solenoid valve 40a to a closed state and the second solenoid valve 40b to an open state, while controlling the motor 50 to be driven. As a result, the brake fluid is released from the wheel cylinder 24 to the accumulator 26, the hydraulic pressure of the brake fluid in the wheel cylinder 24 is reduced, and the braking force of the front wheels 4 is reduced, thereby unlocking the rotation of the front wheels 4 or preventing the front wheels 4 from locking. In addition, the brake fluid released to the accumulator 26 is pumped up by a pump 27 driven by a motor 50 and returned to an area of ​​the main fluid path 23b that is closer to the master cylinder 21 than the first solenoid valve 40a.

[0052]

[0030] The brake fluid pressure control device 10 may be configured to include a fluid pressure sensor that detects the fluid pressure of the brake fluid input from the master cylinder 21, and / or a fluid pressure sensor that detects the fluid pressure of the brake fluid output to the wheel cylinder 24. Such a fluid pressure sensor may be, for example, configured to be arranged in the main flow path or sub-flow path of the brake fluid pressure control device, or configured to be arranged in a brake fluid pipe connected to the main flow path, or configured to be arranged in the master cylinder or wheel cylinder.

[0053]

[0031] The brake fluid pressure control device 10 may also be configured to include a fluid path or the like that allows the pump 27 to draw up brake fluid from the reservoir 22 and output the brake fluid to the wheel cylinder 24. In such a configuration, the control board 70 may be configured to perform a front wheel pressure increasing operation that increases the hydraulic pressure of the brake fluid in the wheel cylinder 24 with the brake fluid output by the pump 27 when it is determined that the braking force of the front wheels 4 is insufficient or may be insufficient based on the detection results of various sensors, for example. In such a configuration, the pressure increasing operation can increase the braking force of the front wheels 4 to compensate for the insufficient braking force.

[0054]

[0032] As shown in FIG. 3, the brake fluid pressure control device 10 is configured by unitizing a base body 60 in which part of the brake fluid path described above is formed as an internal fluid path, first and second solenoid valves 40a, 40b, a pump 27, an accumulator 26, a motor 50, a control board 70, and a housing 80 that houses the control board 70 and the like.

[0055]

[0033] The base 60 is formed, for example, from a rectangular parallelepiped block of aluminum. Inside the base 60, the above-mentioned main liquid path 23b and sub liquid path 23c are formed.

[0056]

[0034] A motor hole 61H for accommodating a motor 50 is formed in approximately the center of a first surface 60A constituting the exterior of the base 60, and one end of the motor 50 is inserted into the motor hole 61H (see FIG. 5). A pump hole 64H for accommodating a plunger 27e of a pump 27 (described below) is formed on a second surface 60B continuing from the first surface 60A of the base 60 and constituting the exterior. The base 60 also has assembly holes for assembling the first and second solenoid valves 40a, 40b and the accumulator 26, and insertion holes for inserting bolts that secure the housing 80 to the base 60. In addition, each surface that constitutes the exterior of the base 60 may include a stepped portion or a curved portion.

[0057]

[0035] A third surface 60C of the base 60, which continues from the first surface 60A and forms the exterior, is provided with a master cylinder port P1 that forms part of the fluid path 23 and is connected to a brake fluid pipe 23a that connects the master cylinder 21 and the main fluid path 23b, and a wheel cylinder port P2 that forms part of the fluid path 23 and is connected to a brake fluid pipe 23d that connects the wheel cylinder 24 and the main fluid path 23b.

[0058]

[0036] The motor 50 is attached to the base 60 with one end of its output shaft 51 inserted into the motor hole 61H. As will be described later, an eccentric body 52 that rotates together with the output shaft 51 is attached to one end of the output shaft 51. The motor 50 also has an electrical terminal at the end opposite to the side where the output shaft 51 is provided, which is electrically connected to the control board 70. In this embodiment, the motor 50 is attached to the base 60, but the motor may also be attached to, for example, a housing.

[0059]

[0037] As will be described later, the plunger 27e of the pump 27 is disposed inside the pump hole 64H so as to be pressed against the outer peripheral surface of the eccentric body 52. ​​When the eccentric body 52 rotates, the plunger 27e reciprocates in the axial direction of the pump hole 64H, thereby transporting brake fluid from the suction side to the discharge side of the pump 27.

[0060]

[0038] The control board 70 has electrical wiring and various electronic components (for example, integrated circuit chips) that constitute the controller and electronic circuit arranged on the board, and is housed inside the housing 80. The electronic circuit of the control board 70 is electrically connected to the electrical terminals of the motor 50, the terminals of the first and second solenoid valves 40a, 40b, the output terminals of various sensors (not shown), and a connector that is connected to an external device (not shown) provided outside the brake fluid pressure control device 10.

[0061]

[0039] The housing 80 is made of, for example, resin and is formed in a substantially rectangular parallelepiped shape. The housing 80 includes a first housing 81 that houses the first and second solenoid valves 40a, 40b and the motor 50, and a second housing 87 that houses the control board 70. Each surface that constitutes the exterior of the housing 80 may be formed into a shape that includes a stepped portion, a curved portion, or the like.

[0062] [ 0 0 4 0 ]

[0063] <Regarding the pump and motor> The pump 27 and motor 50 assembled to the base 60 will be described with reference to Figs. 4 to 6. Fig. 4 is a cross-sectional view showing the periphery of the pump 27 assembled to the base 60, taken along a plane perpendicular to the rotation axis of the output shaft 51 of the motor 50. Fig. 5 is a cross-sectional view showing the periphery of the motor 50 assembled to the base 60, taken along a plane including the rotation axis of the output shaft 51 of the motor 50. Fig. 6 is a diagram for explaining a modified example of the motor 50.

[0064]

[0041] As shown in FIG. 4, the pump 27 includes a cylinder 27a disposed in a pump hole 64H drilled in the base 60, a plunger 27e, and a spring 27g.

[0065]

[0042] The cylinder 27a is formed with a compression chamber 27b in which the brake fluid is compressed by the reciprocating motion of a plunger 27e, an inlet hole 27c through which the brake fluid flows into the compression chamber 27b, and an outlet hole 27d through which the brake fluid compressed in the compression chamber 27b flows out. The inlet hole 27c is connected to the accumulator 26 side of the auxiliary fluid path 23c via a first check valve (not shown) provided in the base 60. The outlet hole 27d is connected to the main fluid path 23b side of the auxiliary fluid path 23c via a second check valve (not shown) provided in the base 60. In addition, the cylinder 27a is pressed into the pump hole 64H to seal the pump hole 64H.

[0066] One end of the plunger 27e abuts against and is pressed by the eccentric body 52, and the other end is urged toward the eccentric body 52 by a spring 27g. The rotational motion of the eccentric body 52 is converted into linear motion, causing the other end to reciprocate within the compression chamber 27b and compress the brake fluid. A seal member 27f (e.g., an O ring) is disposed on the outer circumferential surface of the plunger 27e to seal between the outer circumferential surface and the inner circumferential surface of the pump hole 64H, thereby preventing brake fluid from leaking from the compression chamber 27b side to the eccentric body 52 side of the motor 50 inside the pump hole 64H.

[0067]

[0044] Although the pump 27 of this embodiment is configured to include one plunger 27e, and the plunger is arranged only on one side of the eccentric body, the pump may be configured to include multiple plungers, and the plungers may be arranged in positions where they do not face each other across the eccentric body, for example, a configuration in which three plungers are arranged at 120° intervals in the radial direction of the eccentric body, or a configuration in which two plungers are arranged side by side in the direction of the rotation axis of the eccentric body. Furthermore, although the plunger 27e of this embodiment is configured by a single member, the plunger 27e may be configured by a plurality of members (for example, a configuration in which a first member having one end side abutting against the eccentric body and being pressed, and a second member having one end side abutting against a spring and being pressed, etc.).

[0068]

[0045] As shown in FIG. 5, the motor 50 includes a motor main body 50a, an output shaft 51 driven by the motor main body 50a, and an eccentric body 52 provided at one end of the output shaft 51 and rotating eccentrically with respect to the center of rotation of the output shaft 51.

[0069]

[0046] The motor main body 50a includes a rotor and a stator (not shown) that drive the output shaft 51, a first bearing 50b and a second bearing 50c that hold the output shaft 51, and a motor housing that accommodates these. The first bearing 50b and the second bearing 50c are, for example, ball bearings.

[0070]

[0047] The output shaft 51 is held by a tight fit in a first bearing 50b and a second bearing 50c provided in a motor body 50a. A first region 51a, which is a region of the output shaft 51 that protrudes from the second bearing 50c toward the opposite side from the first bearing 50b, protrudes to the outside of the motor housing, and an eccentric body 52 is provided in the first region 51a. A bearing portion 52a that rotates in the rotational direction of the eccentric body 52 is provided on the outer periphery of the eccentric body 52, and the outer periphery of the bearing portion 52a presses against a plunger 27e of a pump 27 to cause it to reciprocate (see FIG. 4). A second region, which is the region between the first bearing 50b and the second bearing 50c in the output shaft 51, is disposed within the motor housing, and the motor 50 is disposed in the motor hole 61H with the end 51c of the first region of the output shaft 51 being an unsupported free end.

[0071]

[0048] In this way, the output shaft 51 of the motor 50 is tightly fitted into the first bearing 50b and the second bearing 50c provided in the motor housing and held therein, and the eccentric body 52 is provided in a first region 51a of the output shaft 51 that protrudes from the second bearing 50c to the side opposite to the first bearing 50b. When the eccentric body 52 presses the plunger 27e, the eccentric body 52 receives a reaction force from the plunger 27e only from one side or from sides that do not face each other, and the reaction force deforms the first region 51a of the output shaft 51, causing the center C' of the end 51c of the first region to move to a position farther from the plunger 27e than the center C of the second region 51b between the first bearing 50b and the second bearing 50c of the output shaft 51. As a result, the center of rotation of the eccentric body 52 is located farther from the plunger 27e than the center C of the second region of the output shaft 51, and the stroke length of the reciprocating motion of the plunger 27e can be shortened compared to when the center C' of the end 51c of the output shaft 51 is located at a position coinciding with the center C of the second region, thereby reducing the torque required to drive the pump 27.

[0072]

[0049] Therefore, in the brake fluid pressure control device 10 of this embodiment, the pump 27 can be driven by the motor 50, which has a relatively small maximum output torque, allowing for the miniaturization and low cost of the brake fluid pressure control device and motor. Although the output flow rate of the pump may decrease when the stroke length of the plunger 27e is shortened, this decrease in flow rate can be compensated for by increasing the rotation speed of the motor 50. For example, by moving the center C' of the end 51c of the output shaft 51 so as to shorten the stroke of the plunger 27e by approximately 20-30%, the torque required to drive the pump 27 can be reduced while suppressing an increase in friction loss due to deformation of the output shaft 51.

[0073]

[0050] Conventionally, when a motor is under a high load, the temperature of the motor rises as current is applied, and the magnetic flux of the motor tends to decrease, which can result in a decrease in the output torque of the motor under a high load. In conventional brake fluid pressure control devices, in preparation for such a decrease in the motor output torque due to an increase in temperature, a motor with a higher maximum output torque even at normal temperatures is sometimes selected, which can result in an increase in the size and cost of the brake fluid pressure control device and motor.

[0074] In contrast, in the pump 27 of this embodiment, when the eccentric body 52 presses the plunger 27e, the reaction force received from the plunger 27e becomes larger when the hydraulic pressure of the brake fluid compressed by the pump 27 is high and the pump load is high (for example, when the hydraulic pressure of the master cylinder 21 is supplied to the pump 27 during the above-mentioned anti-lock operation). As a result, the end 51c of the first region 51a of the output shaft 51, which moves due to the reaction force of the plunger 27e, moves to a position farther away from the plunger 27e, and the stroke length of the plunger 27e is further shortened. Therefore, when the output torque of the motor 50 decreases when the pump load is high, the torque required to drive the pump 27 can be reduced as the pump load increases, and the driving of the pump 27 can be prevented from being stopped and can be continued.

[0075]

[0052] In the present embodiment, the motor 50 is configured to be disposed in the motor hole 61H with the end 51c of the first region of the output shaft 51 as an unsupported free end, but the motor 50 may be configured to be disposed in the motor hole 61H with the end 51c of the output shaft 51 as a fixed end. For example, as shown in Fig. 6, a third bearing 53 may be provided at the bottom of the motor hole 61H in the base 60, and the end 51c side of the output shaft 51 of the motor 50 may be inserted into the third bearing 53 by clearance fit, so that the motor 50 is disposed in the motor hole 61H with the end 51c of the output shaft 51 as a fixed end. With this configuration, the range of movement of the end 51 c of the first region 51 a of the output shaft 51 when the pump 27 is running, i.e., the shortening of the stroke length of the plunger 27 e, can be limited to the range of the gap width between the outer peripheral surface of the output shaft 51 and the inner peripheral surface of the third bearing 53. For example, the amount of movement B (see FIG. 6) when the end 51 c of the first region of the output shaft 51 is a supported fixed end can be made smaller than the amount of movement A (see FIG. 5) when the end 51 c of the first region of the output shaft 51 is an unsupported free end. The third bearing 53 may be, for example, a bearing or a bushing.

[0076]

[0053] At least one of the material, shape, and outer diameter of the first region 51a of the output shaft 51 may be made different from those of the second region 51a, so that the first region 51a is more easily elastically deformable than the second region 51b.

[0077] [ 0 0 5 4 ]

[0078] <Regarding Operation and Effect> Conventionally, some straddle-type vehicles (e.g., motorcycles, etc.) are equipped with brake fluid pressure control devices that control the hydraulic pressure of brake fluid in a brake system that brakes the wheels. One such brake fluid pressure control device is, for example, configured to be driven by an electric motor and equipped with a pump that pumps brake fluid. When the electric motor is in a driven state, it generates heat when current is applied, causing its temperature to rise. As the temperature of the magnets provided in the electric motor increases, the magnetic flux density tends to decrease, and the output torque of the electric motor decreases as the temperature of the electric motor increases. When the electric motor is in a driven state, the increase in temperature can cause the output torque of the electric motor to decrease below the torque required to continue driving the pump. In such a case, the pump may stop rotating, making it difficult for the brake fluid pressure control device to control the brake fluid pressure.

[0079]

[0055] In contrast, the brake fluid pressure control device 10 of this embodiment includes a pump 27 that pumps brake fluid and a motor 50 that drives the pump 27. The motor 50 includes a motor main body 50a, an output shaft 51 driven by the motor main body 50a, and a motor main body 5. a first bearing 50b and a second bearing 50c provided in a first region 51a of the output shaft 51 and holding the output shaft 51 by an interference fit; and an eccentric body 52 provided in a first region 51a protruding from the second bearing 50c on the output shaft 51 to the side opposite the first bearing 50, and rotating eccentrically with respect to the center of rotation of the output shaft 51. The pump 27 comprises a plunger 27e pressed by the eccentric body 52 and reciprocating inside the cylinder 27a, and a spring 27g that presses the plunger 27e toward the eccentric body 52. ​​The plunger 27e is arranged only on one side of the eccentric body 52 or in positions that do not face each other, and when the pump 27 is in a driving state, The eccentric body 52 receives the reaction force of the plunger 27e only from one side or from sides that do not face each other, and the center C' of the end 51c of the first region 51a of the output shaft 51 is located farther from the plunger 27e pressed by the eccentric body 52 than the center C of the second region 51b between the first bearing 50b and the second bearing 50c on the output shaft 51.

[0080]

[0056] With this configuration, when the pump 27 is in a driving state, the eccentric body 52 receives the reaction force of the plunger 27e only from one direction or from directions that do not face each other. The center C' of the end 51c of the first region 51a of the motor body 50a of the output shaft 51 is located farther from the plunger 27e pressed by the eccentric body 52 than the center C of the second region 51b of the output shaft 51. This shortens the stroke length of the reciprocating motion of the plunger 27e by the distance between the center C' of the end 51c of the first region 51a of the output shaft 51 and the center C of the second region 51b, thereby reducing the torque required to drive the pump 27. As a result, even if the torque of the motor 50 decreases, the torque required to drive the pump 27 can be reduced, allowing the pump 27 to continue to operate.

[0081]

[0057] The motor 50 that drives the pump 27 of the brake fluid pressure control device 10 of this embodiment is configured such that the end 51c of the first region of the output shaft 51 is an unsupported free end.

[0082]

[0058] With this configuration, when the pump 27 is in a driving state, the eccentric body 52 receives a reaction force from the plunger 27e only from one direction or from directions that do not face each other, making it easy to deform the output shaft 51 in accordance with the reaction force. Furthermore, the center C' of the end 51c of the first region 51a of the output shaft 51 can be positioned farther from the plunger 27e pressed by the eccentric body 52 than the center C of the second region 51b between the first bearing 50b and the second bearing 50c of the output shaft 51.

[0083]

[0059] The brake fluid pressure control device 10 of this embodiment includes a motor 50 that drives a pump 27, and the motor 50 is provided on an output shaft 51 and includes an eccentric body 52 that rotates eccentrically about the center of rotation of the output shaft 51, and the eccentric body 52 is provided with a bearing portion 52a that is provided on the outer periphery of the eccentric body 52.

[0084]

[0060] According to this configuration, the eccentric body 52 of the brake fluid pressure control device 10 includes the bearing portion 52a provided on the outer periphery of the eccentric body 52. ​​Therefore, when the rotational motion of the eccentric body 52 is converted into the linear motion of the plunger 27e, the load acting in a direction intersecting the axial direction of the reciprocating motion of the plunger 27e is absorbed by the rotational motion of the bearing portion 52a, and only the load acting in the axial direction of the reciprocating motion of the plunger 27e can be transmitted to the plunger 27e. This reduces deformation of the output shaft 51 in the rotational direction of the eccentric body 52 due to the load from the eccentric body 52 acting in a direction intersecting the axial direction of the reciprocating motion of the plunger 27e.

[0085]

[0061] In this embodiment, the output shaft 51 of the motor 50 is configured such that the end 51c of the first region is an unsupported free end. However, the end 51c of the output shaft 51 of the motor 50 may be configured as a fixed end, for example, such that the end 51c of the output shaft 51 is supported by a clearance fit in a third bearing 53 fixed to the bottom of the motor hole 61H of the base 60. In such a configuration, the range in which the end 51c of the first region 51a of the output shaft 51 moves when the pump 27 is in a driving state, i.e., the shortened stroke length of the plunger 27e, can be limited to within the gap width between the outer peripheral surface of the output shaft 51 and the inner peripheral surface of the third bearing 53.

[0086]

[0062] The motorcycle 1, which is a saddle-ride type vehicle of this embodiment, is configured to include the above-described brake fluid pressure control device 10. With this configuration, the same effects as those of the above-described brake fluid pressure control device 10 can be achieved.

[0087]

[0063] Although the brake fluid pressure control device 10 according to this embodiment has been described above, the brake fluid pressure control device according to the present invention is not limited to the description of this embodiment. For example, only a part of this embodiment may be implemented.

[0088] [Explanation of symbols]

[0089] [ 0 0 6 4 ]

[0090] 1 Motorcycles (saddle-type vehicles)

[0091] 1. Brake fluid pressure control device

[0092] 2 7 Pump

[0093] 2 7 e Plunger

[0094] 5. Motor (electric motor)

[0095] 5 0 a Motor body

[0096] 5 0 b 1st bearing (bearing)

[0097] 5 0 c Second bearing (bearing)

[0098] 5 1 Output shaft

[0099] 5 2 Eccentric body

[0100] 5 3 3rd bearing (bearing)

[0101] 6 〇 Base

[0102] 1 0 0 Brake System

Claims

[Document name] Scope of claims

1. A brake fluid pressure control device for controlling a hydraulic pressure of brake fluid in a brake system (100) mounted on a saddle-ride type vehicle (1), comprising: a base (60) in which a hydraulic path (23) of the brake fluid is formed; a pump (27) for pumping the brake fluid in the hydraulic path (23); and an electric motor (50) erected on the base and driving the pump (27), wherein the electric motor (50) comprises a motor main body (50a), an output shaft (51) driven and rotated by the motor main body, two bearings (50b, 50c) provided on the motor main body (50a) for holding the output shaft (51) by an interference fit, and a bearing (50c) for holding the output shaft (51) by an interference fit between the output shaft (51) and the motor main body (50a). and an eccentric body (52) which is provided in a first region (51a) protruding from one of the bearings (50c) in a direction opposite to the other bearing (50b) side of the output shaft (51), and which rotates eccentrically with respect to the center of rotation of the output shaft (51). The pump (27) includes a plunger (27e) which is pressed by the eccentric body (52) and reciprocates inside the cylinder (27a), and a spring (27g) which presses the plunger (27e) toward the eccentric body (52), the plunger (27e) being disposed only at a position on one side of the eccentric body (52) or at positions not facing each other, and when the pump (27) is in a driving state, the eccentric body (52) a center of an end (51c) of the first region (51a) of the output shaft (51) is located farther from the plunger (27e) pressed by the eccentric body (52) than a center of a second region (51b) between the two bearings (50b, 50c) of the output shaft (51).

2. A brake fluid pressure control device as set forth in claim 1, wherein the end portion (51c) of the output shaft (51) is a free end that is not supported.

3. The output shaft (51) has a bearing (53) provided on the base (60) and the end (5 1c) is a fixed end supported by a clearance fit.

4. A brake fluid pressure control device as claimed in any one of claims 1 to 3, wherein the eccentric body (52) has a bearing portion (52a) provided on an outer periphery of the eccentric body (52).

5. A saddle-type vehicle (1) equipped with a brake fluid pressure control device (10) according to any one of claims 1 to 3.

Images