JP5724493B2 - Master cylinder device - Google Patents

Description

  The present invention relates to a master cylinder device for pressurizing and supplying hydraulic fluid to a brake device provided on a wheel.

  In the master cylinder device, for example, as in the master cylinder device described in the following patent document, the hydraulic fluid that has been pressurized by the high pressure source device is regulated by the pressure regulating device, and the regulated hydraulic fluid Some of them can pressurize the hydraulic fluid depending on the pressure. The master cylinder device has a stroke simulator, that is, a mechanism that applies an operation reaction force to the brake operation member in accordance with the operation force of the driver. Therefore, the master cylinder device can make the driver feel as if the brake device is operating by his / her own brake operation, while providing a hydraulic braking force depending on the pressure of the adjusted hydraulic fluid. It can be generated by a brake device. In other words, this master cylinder device is configured to be able to pressurize the hydraulic fluid regardless of the operation of the brake operation member by the driver (hereinafter, such a master cylinder device is referred to as “independent pressurization type master cylinder”). Sometimes referred to as "device").

JP 2010-927 A

  In hybrid vehicles and electric vehicles that have been developed in recent years, resistance force based on electromotive force of an electric motor or a generator that is rotated by the rotation of wheels is used for braking the vehicle. However, since the braking force based on the resistance force is relatively small, even in these vehicles, the frictional force generated in the brake device depending on the pressure of the hydraulic fluid pressurized by the master cylinder device is used for braking the vehicle. It's being used. The independent pressurization type master cylinder device can control the pressurization of the hydraulic fluid so that a frictional force is generated by the brake device in cooperation with the above-described resistance force regardless of the brake operation, for example. Suitable for use in. However, the independent pressurization master cylinder device still has room for improvement at present, and various improvements can improve the practicality of the independent pressurization master cylinder device. it can. This invention is made | formed in view of such a situation, and makes it a subject to improve the practicality of a master cylinder apparatus.

In order to solve the above-described problems, a master cylinder device according to the present invention includes a pressure piston that pressurizes hydraulic fluid by advancing while a step surface facing forward is formed on the outer peripheral portion, and a brake disposed behind the pressure piston. An input piston that moves forward by operation, and a pressure receiving area in which the pressure of the hydraulic fluid in the inter-piston chamber defined between the pressure piston and the input piston acts on the pressure piston, and a front of the step surface The pressure of the hydraulic fluid inside the reaction force chamber partitioned into two is equal to the pressure receiving area that acts on the pressurizing piston, and further, an inter-chamber communication passage that connects the inter-piston chamber and the reaction force chamber, and electric A forward force applying mechanism that applies one of the force generated by the motor and the force generated by the gas pressure to the pressurizing piston, and a force having a magnitude corresponding to the amount of advance to the input piston while facing the advance of the input piston. Azukasuru a reaction force applying mechanism, in the normal state, blocks the inter-piston chamber and the reaction chamber from the low pressure source, the chamber communicating path that communicates them inter-piston chamber and the reaction chamber, the pressure piston Is not moved by the pressure change of the inter-piston chamber and the reaction force chamber when the input piston is moved forward, and is moved by the forward force by the forward force applying mechanism, and the reaction force applying mechanism. However, the volume of the liquid storage chamber is increased in accordance with the amount of advance of the input piston and the inter-piston chamber and the reaction force. Containing a counter-storage chamber elastic reaction force action mechanism that allows a reduction in the total volume of the chamber and an elastic reaction force of a magnitude corresponding to the increase in the volume of the storage chamber to act on the hydraulic fluid in the storage chamber The input piston The magnitude of the force corresponding to the amount of forward, characterized in that it is configured to apply to the input piston as an operation reaction force.

  The master cylinder device of the present invention is a type of independent pressurization type master cylinder device that can pressurize the hydraulic fluid regardless of the operation of the brake operation member. No pressure regulator is required to regulate the hydraulic fluid. Also, a passage for introducing the regulated hydraulic fluid into the master cylinder device is provided, and a liquid chamber for transmitting the regulated hydraulic fluid pressure to the pressurizing piston is defined in the master cylinder device. You do n’t have to. As a result, the practicality of the master cylinder device is high.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention. Some of the aspects of the claimable invention correspond to the invention according to the claims described in the claims.

In each of the following items, the combination of the items (1) and (12) and a limitation on the configuration relating to the inter-piston chamber and the reaction force chamber correspond to claim 1, and the item (3) is claimed. Claim 2, Claim (4) is Claim 3, Claim (7) is Claim 4, Claim (8) is Claim 5, Claim (10) is Claim 6, Claim (12) is Claim Each corresponds to item 7.

(1) A master cylinder device for supplying pressurized hydraulic fluid to a brake device provided on a wheel,
A cylindrical housing with a closed front end;
A pressurizing piston having a stepped surface having a stepped surface facing forward at the outer periphery, and supplying hydraulic fluid pressurized to the brake device by its own advancement disposed in the housing;
An input piston disposed behind the pressurizing piston in the housing and connected to a brake operation member to advance by a driver's brake operation;
An inter-piston chamber defined between the input piston and the pressurizing piston;
The pressure piston is partitioned by the pressure piston and the housing in front of the stepped surface, and the pressure receiving area where the pressure of the hydraulic fluid inside the pressure piston acts on the pressure piston is the pressure of the hydraulic fluid inside the inter-piston chamber. A reaction force chamber made equal to the pressure receiving area acting on the pressure piston,
An inter-chamber communication passage communicating the inter-piston chamber and the reaction force chamber;
A forward force applying mechanism that applies one of the force generated by the electric motor and the force generated by the gas pressure to the pressurizing piston as a forward force that is a force for advancing it;
A master cylinder provided with a reaction force application mechanism that applies a force that opposes the advance of the input piston and that corresponds to the amount of advance to the input piston as an operation reaction force to the operation of the brake operation member. apparatus.

  According to the master cylinder device of the present invention, the pressure receiving area where the pressure of the hydraulic fluid inside the reaction force chamber acts on the pressure piston is the pressure receiving area where the pressure of the hydraulic fluid inside the chamber between the pistons acts on the pressure piston. Since the pressure piston is moved forward by the forward force, the amount of decrease in the hydraulic fluid in one of the inter-piston chamber and the reaction force chamber is equal to the amount of increase in the hydraulic fluid in the other because the area is equal. . In other words, the master cylinder device is configured such that the hydraulic fluid moves between the piston chamber and the reaction force chamber when the pressurizing piston moves forward by a forward force. Therefore, even if the pressurizing piston moves forward by the forward force, the input piston is not moved thereby. Further, in this master cylinder device, the pressure receiving areas described above are equal, so that the forward biasing force acting on the pressure piston by the pressure of the hydraulic fluid in the inter-piston chamber and the pressure of the hydraulic fluid in the reaction force chamber Thus, the rearward urging force acting on the pressure piston has the same magnitude. Therefore, when the input piston is moved forward by the operating force, even if the pressure of the hydraulic fluid in the inter-piston chamber and the reaction force chamber changes, the pressure piston is not moved by the pressure change. Further, in this master cylinder device, the driver can feel the force applied to the input piston by the reaction force applying mechanism as an operation reaction force with respect to his / her brake operation. In other words, the master cylinder device is as if the brake device is operated by its own brake operation even when the driver's operating force is not used for the advance of the pressurizing piston, that is, for pressurizing the hydraulic fluid. Can make the driver feel. Therefore, this master cylinder device is an independent pressurization type master cylinder device constituted so that hydraulic fluid can be pressurized irrespective of operation of a brake operation member by a driver.

  In this master cylinder device, the pressurizing piston is advanced by the force generated by the electric motor or the force generated by the gas pressure. Therefore, the master cylinder device does not require a high-pressure source device or a pressure adjusting device, which makes the master cylinder device practical. Further, in this master cylinder device, a passage for introducing the adjusted hydraulic fluid into the master cylinder device is provided, or a liquid chamber for transmitting the pressure of the adjusted hydraulic fluid to the pressurizing piston is provided in the master cylinder. Since it is not necessary to form a partition in the device, the structure of the master cylinder device is relatively simple. This also makes the master cylinder device highly practical.

  In the reaction force application mechanism of the master cylinder device, the specific means for applying the operation reaction force to the input piston is not particularly limited. For example, the reaction force application mechanism may be a mechanism including an elastic body such as a spring that applies an elastic reaction force to the advance of the input piston. In addition, since the pressure of the hydraulic fluid in the inter-piston chamber acts as an urging force to the rear and acts on the input piston, a mechanism that uses the urging force as an operation reaction force against the brake operation, that is, the operation of the inter-piston chamber A mechanism that pressurizes the liquid may be used.

  (2) The master cylinder device according to (1), wherein the forward force applying mechanism applies the force generated by the electric motor to the pressurizing piston as the forward force.

  In this master cylinder device, the pressure piston is moved forward by the force generated by the electric motor.

(3) The forward force applying mechanism is
A rotating motor as the electric motor that rotates by generating electric power to generate a rotational force;
A master cylinder device according to item (2), including a rotational force conversion mechanism that converts rotational force generated by the rotational motor into the forward force.

  The forward force applying mechanism of the master cylinder device generates a rotational force by an electric motor, and advances the pressure piston by converting the rotational force into the forward force. The rotational force conversion mechanism may be any mechanism that converts rotational motion into linear motion, and includes, for example, a screw mechanism such as a ball screw mechanism described later and a gear mechanism such as a rack and pinion as main components. Any mechanism can be used.

(4) The rotational force conversion mechanism is
A nut that is rotatable by the rotational force of the rotary motor in a state in which it cannot move in the front-rear direction;
The master according to (3), comprising: a plunger that is screwed with the nut in a non-rotatable state and abuts against the pressure piston by the rotational force of the rotary motor to advance the pressure piston. Cylinder device.

  In the rotational force conversion mechanism of the master cylinder device, it can be considered that a screw mechanism is constituted by a nut and a plunger. The screw mechanism may be a mechanism in which a plurality of balls are interposed between the outer peripheral surface of the plunger and the inner peripheral surface of the nut, that is, a ball screw mechanism. In the case of the ball screw mechanism, the frictional force generated between the nut and the plunger is relatively small, so that the loss of the rotational force generated by the rotary motor can be reduced. Therefore, since the rotational force of the motor, that is, the output of the motor can be made relatively small, the motor can be downsized and the power consumption can be reduced.

  (5) The master cylinder device according to (4), wherein the plunger has a cylindrical shape, and the plunger is fitted on the pressurizing piston.

  In this master cylinder device, since the plunger and the pressure piston overlap with each other in the front-rear direction, the master cylinder device can be made relatively compact.

  (6) The master cylinder device according to (1), wherein the forward force applying mechanism applies the force generated by the gas pressure to the pressurizing piston as the forward force.

  In this master cylinder device, the pressurizing piston is moved forward by the force generated by the gas pressure.

(7) The forward force applying mechanism is
A gas container in which a space filled with gas is formed inside the housing;
A partition that is disposed in the gas container and divides the gas container into an atmospheric pressure chamber that communicates with an atmospheric pressure source at the rear of the gas container and a negative pressure chamber that communicates with a negative pressure source at the front of the gas container. And a plunger that abuts against the pressurizing piston by a pressure difference between the pressure in the atmospheric pressure chamber and the pressure in the negative pressure chamber to advance the pressurizing piston. apparatus.

  In the forward force applying mechanism of the master cylinder device, a pressure difference is generated between the atmospheric pressure and the negative pressure before and after the partition of the plunger, and the force generated by the pressure difference becomes the force generated by the gas pressure. That is, the forward force applying mechanism of the master cylinder device has the same configuration as a so-called negative pressure booster. The plunger partition body may be any one that partitions the inside of the gas container into an atmospheric pressure chamber and a negative pressure chamber while allowing the plunger to advance. For example, if the piston is in sliding contact with the inner wall of the gas container, the inside of the gas container can be partitioned into an atmospheric pressure chamber and a negative pressure chamber while allowing the plunger to advance. Alternatively, if the diaphragm is fixed to the inner wall of the gas container, and a part of the diaphragm is made of a material having flexibility or stretchability, the inside of the gas container is allowed to move inside the atmospheric pressure chamber while allowing the plunger to advance by deformation of the diaphragm. And a negative pressure chamber. In short, a partition such as a piston can be employed, and a partition such as a diaphragm can also be employed.

  The negative pressure source may be a dedicated device capable of creating a negative pressure state such as a vacuum pump, or the intake air of the engine that is in a negative pressure state when the vehicle engine is in operation. Or an intake pipe connected to the engine.

  (8) The master cylinder according to (7), wherein the gas container is formed in an annular shape around the plunger, and the plunger partition is formed in a bowl shape on the outer periphery of the plunger. apparatus.

  According to this master cylinder device, the partition of the plunger is formed as a bowl surrounding the outer periphery of the plunger, and the above pressure difference acts on the entire area of the partition, that is, the entire periphery of the plunger. It will be. That is, the forward force generated by the pressure difference is almost uniformly applied to the plunger over the entire circumference of the plunger.

  (9) The master cylinder device according to (7) or (8), wherein the plunger has a cylindrical shape, and the plunger is fitted on the pressurizing piston.

  In this master cylinder device, since the plunger and the pressure piston overlap with each other in the front-rear direction, the master cylinder device can be made relatively compact.

  (10) The master cylinder device according to any one of (1) to (9), further including an input piston relative advance prohibition mechanism that prohibits the relative advance of the input piston with respect to the pressurizing piston.

  According to this master cylinder device, since the relative advance of the input piston with respect to the pressurization piston is prohibited, the pressurization piston is also advanced together with the input piston by the brake operation. That is, the operating force of the driver is transmitted to the pressurizing piston, and the hydraulic fluid can be pressurized by the operating force. Therefore, if the relative advance of the input piston with respect to the pressurizing piston is prohibited, the hydraulic fluid can be pressurized by the operating force in addition to the forward force. In this case, the pressure piston can be advanced by a relatively large force, and therefore a relatively large hydraulic braking force can be generated in the brake device. Therefore, for example, when a relatively large braking force such as a sudden brake is required, if the master cylinder device is configured to prohibit the relative advance of the input piston with respect to the pressure piston, the forward force and the operating force A relatively large hydraulic braking force can be generated. In addition, when a large hydraulic braking force is to be generated depending only on the forward force, for example, it is necessary to increase the size of the electric motor or increase the gas pressure. May lead to shape. According to this master cylinder device, it is possible to configure the master cylinder device so as to generate a relatively large hydraulic braking force without increasing the cost or increasing the size.

  In addition, for example, when a failure occurs in the forward force applying mechanism, or when the forward force applying mechanism cannot be operated due to an electrical failure, the master cylinder device is set so as to prohibit the relative advance of the input piston with respect to the pressure piston. If comprised, a pressurization piston can be advanced by operating force. Therefore, with the master cylinder device configured as described above, even if the forward force applying mechanism cannot apply the forward force to the pressure piston, the hydraulic braking force can be generated by the operation force. . In other words, an excellent master cylinder device can be configured from the viewpoint of fail-safe.

  In order to prohibit the relative advance of the input piston with respect to the pressure piston, for example, the contact of the input piston with the pressure piston may be permitted. By abutting, the operating force is directly transmitted from the input piston to the pressurizing piston, and the pressurizing piston can be advanced by the operating force. Moreover, in order to prohibit the relative advance of the input piston with respect to the pressurizing piston, the inter-piston chamber may be sealed. By the sealing, the operating force is transmitted from the input piston to the pressurizing piston via the hydraulic fluid in the inter-piston chamber, and the pressurizing piston can be advanced by the operating force.

  (11) Between the reaction force chamber and the piston, the input piston relative advance prohibition mechanism allows the input piston to contact the pressurizing piston by communicating the reaction force chamber and the inter-piston chamber with a low pressure source. The master cylinder device according to item (10), including a low pressure source communication mechanism for a room.

  According to this master cylinder device, the input piston can move forward while allowing the hydraulic fluid in the inter-piston chamber to flow out to the low-pressure source by contacting the inter-piston chamber to the low-pressure source, and contact the pressurizing piston. Is acceptable. In the case of contact, as described above, the pressurizing piston is moved forward by the operating force, and a hydraulic braking force is generated depending on the operating force. Further, according to the master cylinder device, the reaction force chamber as well as the inter-piston chamber communicates with the low pressure source, so the pressure of the hydraulic fluid inside the reaction force chamber acts on the step surface of the pressurizing piston, and the reaction force chamber The pressure does not act as a resistance force against the advance of the pressurizing piston. Therefore, even when the pressure piston is moved forward by the operating force, it can be moved relatively easily.

  (12) One of the pressurizing piston and the input piston has a bottomed hole that opens toward the other, and the other of the pressurizing piston and the input piston is fitted into the bottomed hole. The master cylinder device according to any one of (1) to (11), wherein the inter-piston chamber is formed in the bottomed hole.

  In particular, the master cylinder device has a bottomed hole in the pressurizing piston and, as described above, the master cylinder device is configured so that the plunger is fitted over the pressurizing piston. It can be made relatively compact. That is, when the master cylinder device is configured in this way, the inter-piston chamber can be provided at a position where the plunger and the pressure piston overlap in the front-rear direction. Therefore, since the length in the front-rear direction necessary for the plunger and the space in the front-rear direction necessary for the inter-piston chamber can be ensured, they can be arranged so as to overlap in the front-rear direction, so that the front-rear direction of the master cylinder device Can be shortened.

(13) The reaction force applying mechanism is
A liquid storage chamber communicating with the reaction force chamber and the inter-piston chamber;
Allowing the volume of the storage chamber to increase in response to a decrease in the total volume of the reaction force chamber and the inter-piston chamber, and acts on the hydraulic fluid in the storage chamber with an elastic reaction force of a magnitude corresponding to the amount of the increase. The master cylinder device according to any one of (1) to (12), wherein the master cylinder device includes an elastic reaction force acting mechanism against the liquid storage chamber.

  According to this master cylinder device, the elastic reaction force by the storage chamber elastic reaction force acting mechanism acts on the hydraulic fluid in the reaction chamber and the inter-piston chamber together with the hydraulic fluid in the storage chamber. Therefore, if the input piston moves forward, that is, the amount of brake operation increases and the total volume of the reaction force chamber and the inter-piston chamber decreases, the volume of the decrease increases in the liquid storage chamber, and the elastic reaction force increases. become. Therefore, the pressure of the hydraulic fluid in the reaction force chamber and the inter-piston chamber will increase, and the input piston will be given a force that opposes its own advance and that is in accordance with the amount of advance. Become. In the master cylinder device, as described above, the pressure piston is not moved by the pressure of the hydraulic fluid in the inter-piston chamber. Therefore, even if the pressure of the working fluid in the inter-piston chamber changes, the pressure piston is not moved by the change in the pressure. The reaction force applying mechanism of the master cylinder may be provided externally, that is, outside the housing, or may be provided internally, that is, provided inside the housing.

It is a schematic diagram which shows the drive system and braking system of a hybrid vehicle carrying the master cylinder apparatus of the Example of claimable invention. It is a figure which shows the hydraulic brake system comprised including the master cylinder apparatus of 1st Example. It is a figure which shows the reaction force provision mechanism employ | adopted as the master cylinder apparatus shown in FIG. It is a figure which shows the hydraulic brake system comprised including the master cylinder apparatus of 2nd Example. It is a figure which shows the hydraulic brake system comprised including the master cylinder apparatus of the modification.

  Hereinafter, embodiments of the claimable invention will be described in detail with reference to the drawings. The claimable invention is not limited to the following examples and modifications, and can be implemented in various modes with various changes and improvements based on the knowledge of those skilled in the art.

≪Vehicle configuration≫
FIG. 1 schematically shows a drive system and a braking system for a hybrid vehicle equipped with the master cylinder device of the first embodiment. In the vehicle, an engine 10 and an electric motor 12 are mounted as power sources, and a generator 14 that generates electric power by the output of the engine 10 is also mounted. The engine 10, electric motor 12, and generator 14 are connected to each other by the power split mechanism 11. By controlling this power split mechanism 11, the output of the engine 10 can be divided into an output for operating the generator 14 and an output for rotating the driving wheel of the four wheels 13. The output of the electric motor 12 can be transmitted to the drive wheels. That is, the power split mechanism 11 functions as a transmission related to the driving force transmitted to the drive wheels via the speed reducer 15 and the drive shaft 17. In addition, some components such as “wheel 13” correspond to the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel, respectively, when indicating that they correspond to any of the four wheels. The subscripts “FL”, “FR”, “RL”, and “RR” are used. According to this notation, the driving wheels in the vehicle are the wheel 13RL and the wheel 13RR.

  The electric motor 12 is an AC synchronous motor and is driven by AC power. The vehicle is provided with an inverter 24, and the inverter 24 can convert electric power from direct current to alternating current or from alternating current to direct current. Therefore, by controlling the inverter 24, the AC power output from the generator 14 is converted into the DC power for storing in the battery 26, or the DC power stored in the battery 26 is converted into the electric motor. 12 can be converted into AC power for driving the motor 12. Like the electric motor 12, the generator 14 has a configuration as an AC synchronous motor. That is, in the vehicle of the present embodiment, it can be considered that two AC synchronous motors are mounted, and one is used mainly as an electric motor 12 for outputting driving force, and the other is a generator. 14 is mainly used for power generation by the output of the engine 10.

  The electric motor 12 can also generate power (regenerative power generation) by using the rotation of the wheels 13RL and 13RR as the vehicle travels. At this time, in the electric motor 12 connected to the wheels 13RL and 13RR, electric power is generated and a resistance force for stopping the rotation of the electric motor 12 is generated. Therefore, the resistance force can be used as a braking force for braking the vehicle. That is, the electric motor 12 is used as a regenerative brake means for braking the vehicle while generating electric power. Therefore, in this vehicle, the regenerative brake is used for braking the vehicle together with the engine brake and the hydraulic brake described later. On the other hand, the generator 14 generates power mainly by the output of the engine 10, but also functions as an electric motor when electric power is supplied from the battery 26 via the inverter 24.

  In the present vehicle, the above-described brake control and various types of control relating to other vehicles are performed by a plurality of electronic control units (ECUs). Of the plurality of ECUs, the main ECU 30 has a function of supervising these controls. For example, the hybrid vehicle can travel by driving the engine 10 and the electric motor 12. The driving of the engine 10 and the driving of the electric motor 12 are comprehensively controlled by the main ECU 30. . Specifically, the distribution of the output of the engine 10 and the output of the electric motor 12 is determined by the main ECU 30, and the engine ECU 32 that controls the engine 10, the electric motor 12, and the motor that controls the generator 14 based on the distribution. Commands for each control are output to the ECU 34.

  A battery ECU 36 that controls the battery 26 is also connected to the main ECU 30. The battery ECU 36 monitors the state of charge of the battery 26, and outputs a charge request command to the main ECU 30 when the amount of charge is insufficient. The main ECU 30 that has received the charge request command outputs a power generation command from the generator 14 to the motor ECU 34 in order to charge the battery 26.

  The main ECU 30 is also connected to a brake ECU 38 that controls the brake. The vehicle is provided with a brake operation member (hereinafter sometimes simply referred to as an “operation member”) that is operated by the driver, and the brake ECU 38 has a brake operation amount (hereinafter referred to as an operation amount of the operation member). May be simply referred to as an “operation amount”) and a brake control force that is a driver's force applied to the operation member (hereinafter, also referred to simply as “operation force”). The power is determined and this target braking force is output to the main ECU 30. The main ECU 30 outputs this target braking force to the motor ECU 34, and the motor ECU 34 controls the regenerative braking based on the target braking force, and the execution value thereof, that is, the generated regenerative braking force is supplied to the main ECU 30. Output to. In the main ECU 30, the regenerative braking force is subtracted from the target braking force, and a target hydraulic braking force to be generated in the hydraulic brake system 40 mounted on the vehicle is determined based on the subtracted value. The main ECU 30 outputs the target hydraulic braking force to the brake ECU 38, and the brake ECU 38 performs control so that the hydraulic braking force generated by the hydraulic brake system 40 becomes the target hydraulic braking force.

≪Configuration of hydraulic brake system≫
The hydraulic brake system 40 mounted on the hybrid vehicle configured as described above will be described in detail with reference to FIG. In the following description, “front” represents the left side in FIG. 2, and “rear” represents the right side in FIG. In addition, “front side”, “front end”, “forward”, “rear side”, “rear end”, “reverse”, and the like are also represented in the same manner. In the following description, characters enclosed in [] are used when a sensor or the like is shown in the drawings.

  FIG. 2 schematically shows a hydraulic brake system 40 provided in the vehicle. The hydraulic brake system 40 has a master cylinder device 50 for pressurizing hydraulic fluid. The driver of the vehicle can operate the master cylinder device 50 by operating the operating device 52 connected to the master cylinder device 50, and the master cylinder device 50 pressurizes the hydraulic fluid by its own operation. The pressurized hydraulic fluid is supplied to a brake device 56 provided on each wheel via an antilock device 54 connected to the master cylinder device 50. The brake device 56 generates a force for stopping the rotation of the wheel 13, that is, a hydraulic braking force, depending on the pressure of the pressurized hydraulic fluid (hereinafter sometimes referred to as “master pressure”). . The hydraulic brake system 40 has a reservoir 62 that stores hydraulic fluid under atmospheric pressure as a low pressure source. The reservoir 62 is connected to the master cylinder device 50.

  The operation device 52 includes a brake pedal 70 as a brake operation member and an operation rod 72 connected to the brake pedal 70. The brake pedal 70 is rotatably held by the vehicle body at the upper end portion. The operation rod 72 is connected to the brake pedal 70 at the rear end, and is connected to the master cylinder device 50 at the front end. The operation device 52 includes an operation amount sensor [SP] 74 for detecting the operation amount of the brake pedal 70 and an operation force sensor [FP] 76 for detecting the operation force. The operation amount sensor 74 and the operation force sensor 76 are connected to the brake ECU 38, and the brake ECU 38 determines a target braking force based on the detection values of these sensors.

  The brake device 56 is connected to the master cylinder device 50 via liquid passages 80 and 82. The fluid passages 80 and 82 are fluid passages for supplying hydraulic fluid pressurized to the master pressure by the master cylinder device 50 to the brake device 56. A master pressure sensor [Po] 84 is provided in the fluid passage 80, and the master pressure sensor 84 is connected to the brake ECU 38. Although not described in detail, each brake device 56 includes a brake caliper, a wheel cylinder (brake cylinder) and a brake pad attached to the brake caliper, and a brake disk that rotates with each wheel. . The fluid passages 80 and 82 are connected to the brake cylinder of each brake device 56, and an antilock device 54 is provided in the middle of the fluid passages 80 and 82. Incidentally, the fluid passage 80 is connected to the rear-wheel brake devices 56RL and 56RR, and the fluid passage 82 is connected to the front-wheel brake devices 56FL and 56FR. In each brake device 56, depending on the master pressure, the brake cylinder presses the brake pad against the brake disc, and a hydraulic braking force is generated to stop the rotation of the wheel by the friction generated by the pressing, so that the vehicle is braked. It is.

  The anti-lock device 54 is a general device, and simply has four pairs of on-off valves corresponding to each wheel. One of the pair of on-off valves is a pressure-increasing on-off valve. When the wheel is not locked, the valve is in an open state, and the other is a pressure-reducing on-off valve. When not locked, the valve is closed. When the wheel is locked, the pressure increasing on / off valve blocks the flow of hydraulic fluid from the master cylinder device 50 to the brake device 56, and the pressure reducing on / off valve allows the hydraulic fluid to flow from the brake device 56 to the reservoir. It is configured to allow and unlock the wheels.

<Configuration of master cylinder device>
The master cylinder device 50 includes a housing 100 that is a housing of the master cylinder device 50, a first pressurizing piston 102 and a second pressurizing piston 104 that pressurize the hydraulic fluid supplied to the brake device 56, and an operation by the driver. Is configured to include an input piston 106 that is input through the operating device 112 and a pressurizing piston advance device 108 for advancing the first pressurizing piston 102. In addition, all the figures of the master cylinder apparatus of the Example demonstrated below have shown the state in which brake operation is not performed.

  The housing 100 is divided into a plurality of parts by having different inner diameters. Specifically, a portion having a small inner diameter located on the front side is a front portion 110, an intermediate portion 112 located behind the front portion 110 and having a larger inner diameter than the front portion 110, and an inner diameter located on the rear side. The rear part 114 is made smaller. Further, between the intermediate portion 112 and the rear portion 114, an advance device installation portion 116 in which the pressurizing piston advance device 108 is installed is provided.

  The second pressurizing piston 104 has a bottomed cylindrical shape with a closed rear end, and is slidably fitted to the front portion 110 of the housing 100. The first pressurizing piston 102 includes a main body 118 having a bottomed cylindrical shape whose rear end is closed, and an extension 120 that extends rearward from the main body 118. A flange 124 is formed on the outer peripheral portion at the rear end of the main body 118. Therefore, the main body 118 is formed with a step surface 126 facing forward by the flange 124. Further, the first pressure piston 102 has a bottomed hole 130 that opens at the rear end of the extending portion 120. The first pressurizing piston 102 formed in this manner is slidably fitted to the front part 110 of the housing 100 at the front side of the main body part 118 and to the intermediate part 112 at the outer peripheral part of the flange 124. A first pressurizing chamber for pressurizing hydraulic fluid supplied to the brake devices 56RL and RR provided on the two rear wheels between the first pressurizing piston 102 and the second pressurizing piston 104. R1 is defined and a second pressurizing chamber R2 for pressurizing the hydraulic fluid supplied to the brake devices 56FL and FR provided on the two front wheels is provided in front of the second pressurizing piston 104. Is partitioned. The first pressurizing piston 102 and the second pressurizing piston 104 are composed of a headed pin 132 screwed up at the bottom of a bottomed hole that opens to the front of the first pressurizing piston 102, and a second additional piston. The separation distance is limited within the set range by the pin holding cylinder 134 fixed to the rear end face of the pressure piston 104. In addition, compression coil springs (hereinafter also referred to as “return springs”) 136 and 138 are disposed in the first pressurizing chamber R1 and the second pressurizing chamber R2, respectively. The first pressurizing piston 102 and the second pressurizing piston 104 are urged toward the rear while being urged in a direction away from each other.

  The input piston 106 is roughly cylindrical, and has a small-diameter portion 140 with a small outer diameter located on the front side and a large-diameter portion 142 with a large outer diameter located on the rear side. doing. The input piston 106 is disposed in the housing 100 in a state where the small diameter portion 140 is slidably fitted into the bottomed hole 130 of the first pressure piston 102. With the input piston 106 and the first pressurizing piston 102 arranged in this manner, a space between the pistons filled with the working fluid is provided between the front end surface of the small diameter portion 140 and the bottom surface of the bottomed hole 130. R3 is partitioned. In addition, a reaction force chamber R <b> 4 filled with hydraulic fluid is defined by the first pressurizing piston 102 and the housing 100 in front of the step surface 126. Note that a backward biasing force is generated in the first pressurizing piston 102 by the pressure of the hydraulic fluid in the reaction force chamber R4. The pressure receiving area where the pressure of the hydraulic fluid in the reaction force chamber R4 acts on the first pressurizing piston 102, that is, the step of the first pressurizing piston 102 so that the first pressurizing piston 102 generates a backward biasing force. The area of the surface 126 is a pressure receiving area where the pressure of the hydraulic fluid in the inter-piston chamber R3 acts on the first pressurizing piston 102, that is, the first pressurizing piston 102 so that the first pressurizing piston 102 generates a forward biasing force. The area of the bottom surface of the bottomed hole 130 of the pressure piston 102 is made equal.

  At the rear end of the input piston 106, the front end of the operation rod 72 is used to transmit the operating force of the brake pedal 70 to the input piston 106 and to move the input piston 106 forward and backward according to the amount of operation of the brake pedal 70. Are connected. Incidentally, the input piston 106 is locked by a locking ring 144 fitted in the rear small diameter portion 124 of the housing 100, so that the backward movement is limited. The operation rod 72 is provided with a disk-shaped spring seat 146, and a compression coil spring (hereinafter also referred to as “return spring”) 148 is provided between the spring seat 146 and the housing 100. The operation rod 72 is urged rearward by the return spring 148. Note that a boot 150 is passed between the spring seat 146 and the housing 100 so that the rear portion of the master cylinder device 50 is protected from dust.

  The pressurizing piston advancing device 108 includes an electric rotary motor 160 installed in the advancing device installation portion 116 of the housing 100 and a torque generated by the rotary motor 160, that is, a rotational force, and a forward force, that is, a first force. And a rotational force conversion mechanism 162 that converts the pressure piston 102 into a force that advances the pressure piston 102. The rotary motor 160 is connected to the brake ECU 38. The rotational force conversion mechanism 162 includes a drive gear 164 attached to the motor shaft of the rotary motor 160, and the front side is externally fitted to the extending portion 120 of the first pressure piston 102, and the input piston 106 is disposed inside the rear side. A cylindrical plunger 166 is provided, and a generally cylindrical nut 168 that is screwed into the plunger 166 at the inner peripheral portion and is provided so as not to move in the front-rear direction. The nut 168 includes a screw member 169 that is screwed with the plunger 168 and a driven gear 170 that is externally fitted to the screw member 169 and meshes with the drive gear 164. Each of the drive gear 164 and the driven gear 170 is a bevel gear. The plunger 166 is externally fitted to the first pressure piston 102 in a state where the front end surface is in contact with the surface facing the rear side of the flange 124. In addition, splines that extend in the front-rear direction and can fit with each other are formed on the outer peripheral portion at the rear end of the plunger 166 and the inner peripheral portion in the rear portion 114 of the housing 100. That is, the plunger 166 is slidable in the front-rear direction by being spline-fitted to the housing 100, but cannot be rotated. Incidentally, as with the input piston 106, the plunger 166 is locked by the locking ring 144, so that the backward movement is limited. Further, in the pressurizing piston advancing device 108, spiral grooves 172 and 174 are formed on the outer peripheral surface of the plunger 166 and the inner peripheral surface of the nut 168 so as to face each other. A plurality of balls 176 are fitted in the grooves 172 and 174, and the plunger 166 and the nut 168 are screwed through the balls 176. That is, in the pressure piston advance device 108, a ball screw mechanism is configured by the plunger 166, the nut 168, and the ball 176. When the rotary motor 160 generates torque, the ball screw mechanism generates a forward force on the plunger 166. Is configured to occur. Accordingly, the first pressurizing piston 102 can be advanced by being pushed forward by the plunger 166. In other words, the rotary motor 160 and the rotational force conversion mechanism 162 constitute a forward force applying mechanism that applies a forward force to the first pressure piston 102.

  In the master cylinder device 50 configured as described above, the inter-piston chamber R3 is provided at a position where the plunger 166 of the pressurizing piston advance device 108 and the extending portion 120 of the first pressurizing piston 102 overlap in the front-rear direction. It has been. Therefore, the plunger 166 and the inter-piston chamber R3 are disposed so as to overlap in the front-rear direction while ensuring the length in the front-rear direction necessary for the plunger 166 and the space in the front-rear direction necessary for the inter-piston chamber R3. For this reason, the length of the master cylinder device 50 in the front-rear direction is relatively short.

  The first pressurizing chamber R1 communicates with a liquid passage 80 connected to the antilock device 54 via a communication hole 180 provided in the housing 100, and a communication hole 182 provided in the first pressure piston 102 and It is possible to communicate with the reservoir 62 through a communication hole 184 provided in the housing 100. On the other hand, the second pressurizing chamber R2 communicates with a liquid passage 82 connected to the antilock device 54 via a communication hole 186 provided in the housing 100, and a communication hole provided in the second pressurizing piston 104. It is possible to communicate with the reservoir 62 through a communication hole 190 provided in 188 and the housing 100.

  The housing 100 is provided with a communication hole 184, one end communicating with the reservoir 62, that is, the other end communicating with the outside. The housing 100 is also provided with a communication hole 194 having one end opened to the reaction force chamber R4 and the other end communicating with the outside. The first pressurizing piston 102 is provided with a communication hole 196 having one end communicating with the reaction force chamber R4 and the other end communicating with the inter-piston chamber R3. That is, the inter-piston chamber R3 communicates with the outside through the communication hole 196, the reaction force chamber R4, and the communication hole 194. The communication hole 196 communicates between the inter-piston chamber R3 and the reaction force chamber R4. It is a communication path.

  In the master cylinder device 50 thus formed with the communication hole, one end of the external communication path 198 provided outside the housing 100 is connected to the communication hole 192, and the other end of the external communication path 198 is connected to the other end of the external communication path 198. It is connected to the communication hole 194. Therefore, the inter-piston chamber R3 and the reaction force chamber R4 can communicate with the reservoir 62. In the middle of the external communication path 198, an electromagnetic on-off valve 200 connected to the brake ECU 38 is provided. Note that the on-off valve 200 is a normally open valve that is opened in a non-excited state, and is closed when a normal vehicle is used.

  Further, a reaction force generator 210 through which hydraulic fluid from the master cylinder device 50 flows in and out is provided between the communication hole 194 and the on-off valve 200 in the external communication path 198. FIG. 3 is a cross-sectional view of the reaction force generator 210. The reaction force generator 210 includes a housing 212 that is a housing, and a piston 214 and a compression coil spring 216 disposed inside the housing 212. The housing 212 has a cylindrical shape with both ends closed. The piston 214 has a disk shape and is slidably disposed on the inner peripheral surface of the housing 212. One end of the spring 216 is supported on the inner bottom surface of the housing 212, and the other end is supported on one end surface of the piston 214. Therefore, the piston 214 is elastically supported on the housing 212 by the spring 216. In addition, a liquid storage chamber R <b> 5 is defined in the housing 212 by the other end surface of the piston 214 and the housing 212. The housing 212 is provided with a communication hole 218 having one end opened to the liquid storage chamber R5. The other end of the communication hole 218 is connected to a communication path that branches from the external communication path 198 between the communication hole 194 and the on-off valve 200. Accordingly, the liquid storage chamber R5 communicates with the reaction force chamber R4 and the inter-piston chamber R3. Accordingly, when the total volume of the reaction force chamber R4 and the inter-piston chamber R3 decreases, the volume of the liquid storage chamber R5 increases according to the decrease, and the spring 216 has an elastic reaction force having a magnitude corresponding to the increase amount. Is generated. Since the elastic reaction force acts on the hydraulic fluid in the liquid storage chamber R5, the pressure of the hydraulic fluid in the liquid storage chamber R5 increases. That is, the reaction force generator 210 is a reaction force application mechanism in the master cylinder device 50.

  The reaction force applying mechanism employed in the master cylinder device 50 may be a so-called diaphragm type. That is, even in a reaction force application mechanism in which the liquid storage chamber R5 is partitioned by a diaphragm instead of the piston 214, and the hydraulic fluid is pressurized by the pressure of the gas in the gas chamber provided with the diaphragm interposed therebetween. Good.

≪Operation of master cylinder device≫
The operation of the master cylinder device 50 will be described below. In normal times, that is, when the hydraulic brake system 40 can operate normally, as described above, when the target braking force exceeds the regenerative braking force by the regenerative brake, the excess is determined as the target hydraulic braking force. Is done. In accordance with the target hydraulic braking force, the brake ECU 38 determines the magnitude of the pressure of the hydraulic fluid in the pressurizing chamber R1 and outputs a command for rotating the rotary motor 160 to the rotary motor 160. The rotation motor 160 generates torque in the direction of forward rotation, and the torque is transmitted to the first pressure piston 102. That is, a forward force is applied to the first pressure piston. The first pressurizing piston 102 moves forward by the forward force, the hydraulic fluid in the first pressurizing chamber R1 is pressurized, the second pressurizing piston 104 moves forward by the pressure of the hydraulic fluid, and the second pressurizing chamber. The hydraulic fluid in R2 is pressurized. Therefore, each brake device 56 generates a hydraulic braking force. During normal times, the brake ECU 38 monitors whether the master pressure has a magnitude corresponding to the target hydraulic braking force using the output value of the master pressure sensor 84. That is, the brake ECU 38 outputs a command for adjusting the torque generated by the rotating motor 160 to the rotating motor 160 so that the master pressure becomes a pressure corresponding to the target hydraulic braking force. The rotation motor 160 adjusts the current supplied to itself based on the command, and adjusts the torque generated by itself, that is, the rotational force.

  As described above, when the input piston 106 moves forward with respect to the first pressurizing piston 102 and the housing 100 according to the increase in the brake operation amount, the hydraulic fluid in the inter-piston chamber R3 and the reaction force chamber R4 flows out, and between the pistons The total volume of the chamber R3 and the reaction force chamber R4 decreases. Further, normally, the on-off valve 200 is energized and closed. Accordingly, the hydraulic fluid flowing out from the two chambers flows into the liquid storage chamber R5 of the reaction force generator 210, and the volume of the liquid storage chamber R5 increases. Therefore, the elastic reaction force of the spring 216 increases, and the pressure of the hydraulic fluid in the liquid storage chamber R5, the inter-piston chamber R3, and the reaction force chamber R4 increases. Therefore, as the brake operation amount increases, the forward biasing force acting on the first pressurizing piston 102 increases due to the increase of the pressure of the hydraulic fluid in the inter-piston chamber R3, and the reaction chamber R4 operates. As the pressure of the liquid increases, the backward biasing force acting on the first pressure piston 102 increases. As described above, in the master cylinder device 50, the area of the stepped surface 126 of the first pressurizing piston 102 that generates the rearward biasing force is the area of the bottom surface of the bottomed hole 130 of the first pressurizing piston 102. Is equal to. Therefore, the forward biasing force and the backward biasing force have the same magnitude regardless of the pressure of the hydraulic fluid in the inter-piston chamber R3 and the reaction force chamber R4. Therefore, the first pressurizing piston 102 is not moved by the pressure of the hydraulic fluid in the inter-piston chamber R3 and the reaction force chamber R4, but is moved by the advance force generated by the pressurizing piston advance device 108. That is, normally, the hydraulic fluid in the pressurizing chambers R1 and R2 is pressurized by the forward force generated by the pressurizing piston advancement device 108 regardless of the operation force. Therefore, the master cylinder device 50 is an independent pressurizing master cylinder device configured to pressurize the hydraulic fluid regardless of the operation of the brake pedal 70 by the driver.

  Further, since the pressure of the hydraulic fluid in the inter-piston chamber R3 described above also acts on the front end surface of the small diameter portion 140 of the input piston 106, a rearward biasing force is generated with respect to the input piston 106. The rearward urging force is transmitted to the brake pedal 70 via the input piston 106, so that the driver can feel the urging force as an operation reaction force with respect to his own brake operation. Therefore, in the master cylinder device 50, even if the driver's operation force is not used for the advancement of the first pressurizing piston 102, that is, for pressurizing the hydraulic fluid, the brake device 56 is operated by its own brake operation. You can make the driver feel as if you are. That is, it can be considered that the stroke simulator is configured to include the reaction force generator 210 and generate a reaction force according to the operation while allowing the driver to perform the brake operation.

  In the hydraulic brake system 40, for example, when a large hydraulic braking force is required in a sudden braking or the like (hereinafter, sometimes referred to as “when a large braking force is required”), the on-off valve 200 is not excited. And opened. That is, the inter-piston chamber R3 and the reaction force chamber R4 are communicated with the reservoir 62 via the external communication path 198, and the liquid storage chamber R5 of the reaction force generator 250 is also communicated with the reservoir 62. Therefore, the input piston 106 can advance while causing the hydraulic fluid in the inter-piston chamber R <b> 3 to flow out to the reservoir 62. Therefore, the front end surface of the small diameter portion 140 is allowed to contact the first pressurizing piston 102 at the bottom surface of the bottomed hole 130, and the first pressurizing piston 102 is also advanced by the operating force by the contact. be able to. That is, the master cylinder device 50 can pressurize the hydraulic fluid in the pressurizing chambers R1 and R2 by operating force in addition to the forward force generated by the pressure piston advancement device 108 when a large braking force is required. is there. As described above, the master cylinder device 50 includes the on-off valve 200 and causes the inter-piston chamber R3 and the reaction force chamber R4 to communicate with the reservoir 62, thereby bringing the input piston 106 into contact with the first pressurizing piston 102. A permissible low pressure source communication mechanism for the reaction force chamber / piston chamber is configured. Further, since the abutting prohibits the relative advance of the input piston 106 with respect to the first pressurizing piston 102, it can be considered that the mechanism including the on-off valve 200 is an input piston relative advance prohibiting mechanism.

  When a large braking force is required, the reaction force chamber R4 communicates with the reservoir 62 so that the above-described rearward biasing force acting on the first pressurizing piston 102 is not generated. It does not become a resistance force against the forward movement of one pressurizing piston 102. Therefore, even when the first pressurizing piston 102 is moved forward by the operating force, it can be moved relatively easily. Further, when the large braking force is required, the liquid storage chamber R5 is also communicated with the reservoir 62, so that the reaction force generator 210 does not generate an operation reaction force in the master cylinder device 50. However, when pressurizing the hydraulic fluid in the pressurizing chambers R1 and R2 with an operating force, the driver may mainly feel the force due to the pressure of the hydraulic fluid in the pressurizing chambers R1 and R2 as an operation reaction force. it can.

  As described above, in the master cylinder device 50, when a large braking force is required, it is not necessary to depend only on the forward force generated by the pressure piston advance device 108 in order to generate a large hydraulic braking force. A relatively low output motor can be used as the motor 160. In other words, the master cylinder device 50 can generate a relatively large hydraulic braking force without causing an increase in cost due to a high-output motor or an increase in size of the device. Further, in the master cylinder device 50, the torque generated by the rotary motor 160 is converted into a forward force by the ball screw mechanism, so that the loss due to the frictional force or the like in the conversion is relatively small. This also makes it possible for the rotary motor 160 to be a relatively low output motor.

  Next, the operation of the master cylinder device 50 in a situation where electric power is not supplied to the hydraulic brake system 40 due to electrical failure will be described. In the event of an electrical failure, the pressurized piston advancement device 108 cannot be activated. The on-off valve 200 is de-energized and opened. That is, the inter-piston chamber R3, the reaction force chamber R4, and the liquid storage chamber R5 communicate with the reservoir 62. That is, in the master cylinder device 50, the same state as when a large braking force is required, that is, a state in which the input piston 106 is allowed to contact the first pressurizing piston 102 is realized. Therefore, when the brake operation is performed, the front end surface of the small diameter portion 140 of the input piston 106 is allowed to abut on the first pressurizing piston 102 at the bottom surface of the bottomed hole 130, and the first pressure is increased by the abutment. The pressure piston 102 can be advanced by operating force. That is, in the case of an electrical failure, the master cylinder device 50 can pressurize the hydraulic fluid in the pressurizing chambers R <b> 1 and R <b> 2 by operating force, regardless of the forward force generated by the pressurizing piston advancement device 108. become. Thus, in the present master cylinder device 50, even when the pressurizing piston advance device 108 cannot be operated, it is ensured that the brake device 56 is operated to generate the hydraulic braking force, and the fail safe From this point of view, it is an excellent master cylinder device.

  Thus, in the master cylinder device 50, a passage for introducing the regulated hydraulic fluid into the master cylinder device is provided, or a fluid chamber for transmitting the regulated hydraulic fluid pressure to the pressurizing piston. Therefore, the structure of the master cylinder device is relatively simple.

  FIG. 4 shows a hydraulic brake system 240 according to the second embodiment. The hydraulic brake system 240 has a master cylinder device 250, and is roughly configured in the same manner as the hydraulic brake system 240 of the first embodiment. In the following description, considering the simplification of the description, the configuration and operation different from the hydraulic brake system 40 of the first embodiment will be described, and the same configuration and operation as the hydraulic brake system 40 of the first embodiment will be described. Description is omitted.

<Configuration of master cylinder device>
The master cylinder device 250 includes a housing 300 that is a housing of the master cylinder device 250, a first pressurizing piston 302 and a second pressurizing piston 304 that pressurize the hydraulic fluid supplied to the brake device 56, and a driver's operation. Is input through the operating device 52, and includes a pressure piston advance mechanism 308 capable of moving the first pressure piston 302 forward.

  The housing 300 includes a first housing member 310 whose front is closed, and a second housing member 312 which is fitted into the first housing member 310 on the rear side thereof. The first housing member 310 is divided into a small-diameter portion 314 having a small inner diameter located on the front side, and a large-diameter portion 316 having a larger inner diameter than the small-diameter portion 314 located behind the small-diameter portion 314. . Further, the second housing member 312 is provided with an advancement device installation portion 318 in which the pressurizing piston advancement mechanism 308 is installed on the front side, and a rear portion 320 with a reduced inner diameter is provided on the rear side. ing. The advancing device installation portion 318 includes a cylindrical inner cylinder portion 322 having the same inner diameter as that of the rear portion 320 and a casing 324 that partitions an annular space around the inner cylinder portion 322. Has been. The first housing member 310 and the second housing member 312 are integrated in a state where the rear end of the first housing member 310 is fitted into an opening provided at the front end of the casing 324.

  The first pressurizing piston 302 has a main body portion 326 having a bottomed cylindrical shape with a rear end portion closed, and an extending portion 328 extending rearward from the main body portion 326. A flange 330 is formed on the outer peripheral portion at the rear end of the main body 326. Therefore, a step surface 332 facing forward is formed on the main body 326 by the flange 330. The first pressurizing piston 302 has a bottomed hole 334 that opens at the rear end of the extending portion 328. The first pressurizing piston 302 formed in this way has the extended portion 328 disposed in the inner cylindrical portion 322 of the second housing member 312, and the front side of the main body portion 326 is connected to the small diameter portion 314 of the housing 300. The outer periphery of the flange 330 is slidably fitted to the large diameter portion 316.

  The input piston 306 has a generally cylindrical shape and is disposed behind the extending portion 328 of the first pressure piston 302. With the input piston 306 and the first pressurizing piston 302 thus arranged, a space between the front end surface of the input piston 306 and the rear end surface of the extending portion 328 of the first pressurizing piston 302, An inter-piston chamber R13 filled with hydraulic fluid is defined by the space inside the bottomed hole 334. In addition, a reaction force chamber R14 filled with hydraulic fluid is defined by the first pressurizing piston 302 and the first housing member 310 in front of the step surface 332. Note that a rearward biasing force is generated in the first pressurizing piston 302 by the pressure of the hydraulic fluid in the reaction force chamber R14. The pressure receiving area where the pressure of the working fluid in the reaction force chamber R14 acts on the first pressurizing piston 302, that is, the step of the first pressurizing piston 302 so that the first pressurizing piston 302 generates a backward biasing force. The pressure receiving area on the surface 332 is the pressure receiving area where the pressure of the hydraulic fluid in the inter-piston chamber R13 acts on the first pressurizing piston 302 so that the first pressurizing piston 302 generates a forward biasing force, that is, The total area of the rear end surface of the extending portion 328 of the one pressure piston 302 and the bottom surface of the bottomed hole 334 is made equal. Incidentally, the input piston 306 is locked by a locking ring 336 fitted in the rear portion 320 of the second housing member 312, so that the backward movement is limited.

  The pressurizing piston advancing mechanism 308 includes a plunger 340 that is externally fitted to the inner cylindrical portion 322 of the second housing member 312, and an inner peripheral portion of the plunger 340 that is fixed to the plunger 340, and is attached to the casing 324 of the second housing member 312. Are mainly composed of a diaphragm 342 to which the outer peripheral portion is fixed and a compression coil spring 344 that biases the plunger 340 backward. The plunger 340 is slidably fitted to the inner cylindrical portion 322 of the second housing member 312 in a state where the front end surface is in contact with the surface of the first pressure piston 302 facing the rear of the flange 330. Further, a flange 346 extending in the radial direction is formed on the outer periphery behind the plunger 340, and the inner peripheral portion of the diaphragm 344 is fixed to the plunger 340 at the outer peripheral portion of the flange 346. Further, the spring 346 urges the plunger 340 backward by having one end abutting on the front end surface of the casing 324 and the other end abutting on the front surface of the flange 346. The plunger 340 is restricted from moving rearward because the rear end portion abuts against the rear end surface in the casing 324. By the pressurized piston advance mechanism 308 configured in this way, the inside of the casing 324 is divided into a front chamber R16 located on the front side and a rear chamber R17 located on the rear side by the flange 346 and the diaphragm 344. ing.

  The first pressurizing piston 302 is provided with a communication hole 360 having one end communicating with the reaction force chamber R14 and the other end communicating with the bottomed hole 334. That is, the inter-piston chamber R13 communicates with the outside through the communication hole 360, the reaction force chamber R14, and the communication hole 194. The communication hole 360 communicates between the inter-piston chamber R13 and the reaction force chamber R14. It is a communication path. Further, the second housing member is provided with a communication hole 362 having one end opened to the front chamber R16 and the other end opened to the outside in the casing 324, and one end opened to the rear chamber R17. A communication hole 364 whose end opens to the outside is also provided.

  In the master cylinder device 250 in which the communication hole is formed in this way, a negative pressure path 370 is connected to the communication hole 362, and a vacuum that can create a negative pressure state in the middle of the negative pressure path 370. A device 372 is provided. The communication hole 364 is connected to the other end of an atmospheric pressure passage 374 having one end open to the outside, and an electromagnetic on-off valve 376 is provided in the middle of the atmospheric pressure passage 374. Accordingly, the rear chamber R17 can communicate with the outside, which is an atmospheric pressure source. The on-off valve 376 is a normally closed valve that is in a closed state in a non-excited state. Further, in the atmospheric pressure path 374, a communication path 378 is branched from between the communication hole 364 and the on-off valve 376, and the communication path 378 is connected to the negative pressure path 370. An electromagnetic on-off valve 380 is provided in the middle of the communication path 378. The on-off valve 380 is a normally open valve that is opened in a non-excited state. The on-off valves 376 and 380 are connected to the brake ECU 38, respectively.

  The vacuum device 372 mainly includes a vacuum pump 382 that can suck out air, an electric motor 384 that drives the vacuum pump, and a negative pressure tank 386 connected to the vacuum pump 382. The vacuum pump 382 is configured to operate when the pressure in the negative pressure tank 386 exceeds the set level and approaches the atmospheric pressure, and the negative pressure tank 386 is always operated by the operation of the vacuum pump 382. The negative pressure is maintained below the set pressure. Accordingly, the inside of the front chamber R16 is always maintained in a negative pressure state by the vacuum device 372, and the vacuum device 372 is a negative pressure source for filling the front chamber R16 with a negative pressure gas.

  Therefore, in the pressurizing piston advance mechanism 308, a pressure difference is generated between the front chamber R16 set to negative pressure and the rear chamber R17 set to atmospheric pressure. Therefore, the plunger 340 can move forward by the pressure difference generated before and after the rod 346. That is, a forward force, which is a force that advances the first pressurizing piston 302, is generated by the pressure difference between the pressure in the front chamber R16 and the pressure in the rear chamber R17, and the plunger 340 uses the forward force to move the first pressurizing piston 302. The plunger 302 can be advanced. Moreover, the eaves 346 and the diaphragm 344 divide the inside of the casing 324, which is a gas container, into a front chamber R16 that communicates with the vacuum device 372 at the front and a rear chamber R17 that can communicate with the outside at the rear. It is a partition. Therefore, in this master cylinder device 250, a mechanism including the casing 324, the plunger 340, and the diaphragm 344 of the second housing member 312 constitutes a forward force applying mechanism that applies a forward force to the first pressure piston 302. .

≪Operation of master cylinder device≫
The operation of the master cylinder device 250 will be described below. In normal times, that is, when the hydraulic brake system 240 can operate normally and the brake operation is not performed, the on-off valve 376 is de-energized and closed, and the on-off valve 380 is closed. The valve is de-energized and opened. Accordingly, the rear chamber R17 communicates with the vacuum device 372, and the rear chamber R17 is in a negative pressure state, that is, the same pressure as the front chamber R16. Therefore, the plunger 340 is located rearward by the elastic reaction force generated by the spring 346. When the brake operation is performed and the target braking force exceeds the regenerative braking force by the regenerative brake, the on-off valve 376 is excited and opened, and the on-off valve 380 is excited and closed. Therefore, air flows into the rear chamber R17, and a pressure difference is generated between the pressure in the front chamber R16 and the pressure in the rear chamber R17. That is, a forward force is applied to the first pressure piston 102. Further, this forward force increases with an increase in the amount of air flowing into the rear chamber R17, that is, with an increase in the pressure difference between the front chamber R16 and the rear chamber R17. The brake ECU 38 controls the opening and closing of the on-off valves 376 and 380 so that the master pressure becomes a pressure corresponding to the target hydraulic braking force. That is, if the on-off valves 376 and 380 are opened and closed so that the rear chamber R17 communicates with the atmospheric pressure source, the forward force increases and the hydraulic braking force increases, while the rear chamber R17 is vacuumed. If the on-off valves 376 and 380 are respectively opened and closed so as to communicate with the device 372, the hydraulic braking force is reduced. As described above, in the hydraulic brake system 240, the hydraulic braking force is adjusted by opening and closing each of the on-off valves 376 and 380 in normal times.

  When the input piston 306 moves forward in accordance with an increase in the operation amount in the state where the master cylinder device 250 is operated in this way, the on-off valve 200 is closed, so that the liquid storage chamber R5, the inter-piston chamber R13, the reaction force The pressure of the hydraulic fluid in the chamber R14 increases. In the master cylinder device 250, even if the pressure of the hydraulic fluid increases, the force that urges the first pressurizing piston 302 generated by the pressure of the hydraulic fluid in the inter-piston chamber R13 and the reaction force chamber R14 The force for biasing the first pressurizing piston 302 generated by the pressure of the hydraulic fluid has the same magnitude. Therefore, the first pressurizing piston 302 is not moved by the pressure of the hydraulic fluid in the inter-piston chamber R13 and the pressure of the hydraulic fluid in the reaction force chamber R14, but by the advance force generated by the pressurization piston advance mechanism 308. Will move. That is, normally, the hydraulic fluid in the pressurizing chambers R1 and R2 is pressurized by the forward force generated by the pressurizing piston advance mechanism 308 regardless of the operation force. Therefore, the master cylinder device 250 is an independent pressurizing master cylinder device configured to pressurize the hydraulic fluid regardless of the operation of the brake pedal 70 by the driver.

  Further, since the pressure of the hydraulic fluid in the inter-piston chamber R13 also acts on the front end surface of the input piston 306, a rearward biasing force is generated with respect to the input piston 306. Therefore, the driver can feel the urging force as an operation reaction force with respect to his / her brake operation. Therefore, the master cylinder device 250 makes the driver feel as if the brake device 56 is operating by its own brake operation even when the driver's operating force is not used for pressurizing the hydraulic fluid. Can do. That is, it can be considered that the stroke simulator is configured to include the reaction force generator 210 and generate a reaction force according to the operation while allowing the driver to perform the brake operation.

  In the hydraulic brake system 240, when the large braking force is required, the on-off valve 200 is de-energized and opened. That is, the inter-piston chamber R13, the reaction force chamber R14, and the liquid storage chamber R5 are communicated with the reservoir 62. Therefore, the input piston 306 moves forward while allowing the hydraulic fluid in the inter-piston chamber R13 to flow into the reservoir 62, and the front end surface of the input piston 306 contacts the first pressure piston 302 at the rear end surface of the extending portion 328. Is allowed, and the first pressurizing piston 302 can be advanced by an operating force. That is, the master cylinder device 250 can pressurize the hydraulic fluid in the pressurizing chambers R1 and R2 by operating force in addition to the forward force generated by the pressure piston advance mechanism 308 when a large braking force is required. It is configured as follows. Therefore, the master cylinder device 250 can generate a relatively large hydraulic braking force even if the pressurizing piston advance mechanism 308 does not generate a large advance force. Therefore, the master cylinder device 250 can generate a relatively large hydraulic braking force even though the volume in the casing 324 is relatively small and the flange 346 of the plunger 340 is also relatively small. It is said that. In other words, the master cylinder device 250 can generate a relatively large hydraulic braking force without increasing the size of the pressurizing piston advance mechanism 308 and increasing the cost associated therewith. .

  Next, the operation of the master cylinder device 250 in a situation where electric power is not supplied to the hydraulic brake system 240 due to electrical failure will be described. In the event of an electrical failure, the vacuum pump 382 cannot operate. The on-off valve 376 is de-energized and closed, and the on-off valve 380 is de-energized and opened. Therefore, the front chamber R16 and the rear chamber R17 have the same pressure, and no forward force is generated by the pressure piston advance mechanism 308. The on-off valve 200 is de-energized and opened, and the inter-piston chamber R13, the reaction force chamber R14, and the liquid storage chamber R5 communicate with the reservoir 62. Therefore, the contact of the input piston 306 with the first pressurizing piston 302 is allowed, and the first pressurizing piston 302 can be advanced by the operating force. That is, in this master cylinder device 250, in the case of an electrical failure, the hydraulic fluid in the pressurizing chambers R1 and R2 can be pressurized by the operating force, regardless of the forward force generated by the pressurizing piston advance mechanism 308. become. As described above, in the present master cylinder device 250, even when the pressurizing piston advance mechanism 308 cannot be operated, it is ensured that the brake device 56 is operated to generate the hydraulic braking force, and the fail safe is achieved. From this point of view, it is an excellent master cylinder device.

  In the master cylinder device 250, when the engine 10 of the vehicle is in operation, the intake portion of the engine 10 or an intake pipe connected to the engine 10 may be a negative pressure source.

≪Modification≫
FIG. 5 shows a hydraulic brake system 240 in which a master cylinder device 400 is employed instead of the master cylinder device 250. The master cylinder device 400 is roughly configured in the same manner as the master cylinder device 250 except for the input piston 306. In the input piston 402 provided in the master cylinder device 400, the front is a small-diameter portion 404 having a small outer diameter, and the rear is a large-diameter portion 406 having a large outer diameter. The pressure piston 302 is inserted in the bottomed hole 334. In the master cylinder device 400 configured as described above, the space between the front end surface of the small diameter portion 404 and the bottom surface of the bottomed hole 334 and the step surface between the small diameter portion 404 and the large diameter portion 406 extend. An inter-piston chamber R23 is defined including a space between the rear end face of the protruding portion 328. Therefore, in the master cylinder device 400, the inter-piston chamber R23 is provided at a position where the plunger 340 of the pressurizing piston advance mechanism 308 and the extending portion 328 of the first pressurizing piston 302 overlap in the front-rear direction. Therefore, the plunger 340 and the inter-piston chamber R23 are disposed so as to overlap in the front-rear direction while ensuring the length in the front-rear direction necessary for the plunger 340 and the space in the front-rear direction necessary for the inter-piston chamber R23. Therefore, the length of the master cylinder device 400 in the front-rear direction is relatively short.

  40: Hydraulic brake system 50: Master cylinder device 56: Brake device 70: Brake pedal (brake operation member) 100: Housing 102: First pressure piston (pressure receiving piston) 106: Input piston 108: Pressure piston advance device ( 126: Stepped surface 130: Bottomed hole 160: Rotating motor (forward force applying mechanism) 162: Rotational force conversion mechanism (forward force applying mechanism) 166: Plunger 168: Nut 196: Communication hole (inter-chamber communication) 200): Electromagnetic on-off valve (input piston relative advance prohibition mechanism, low pressure source communication mechanism for reaction force chamber / piston chamber) 210: reaction force generator (reaction force applying mechanism) 216: compression coil spring (vs. liquid storage) Chamber elastic reaction force action mechanism) R3: inter-piston chamber R4: reaction force chamber R5: Liquid chamber 240: Hydraulic brake system 250: Master cylinder device 300: Housing 302: First pressurizing piston (pressure receiving piston) 306: Input piston 308: Pressurizing piston advance mechanism (forward force applying mechanism) 324: Chamber portion (gas Container) 332: Stepped surface 334: Bottomed hole (inter-chamber communication passage) 340: Plunger 342: Diaphragm (partition body) 346: Spear (partition body) 360: Communication hole (inter-chamber communication passage) 370: Vacuum device (negative) Pressure source) R13: Inter-piston chamber R14: Reaction force chamber R16: Front chamber (negative pressure chamber) R17: Rear chamber (atmospheric pressure chamber) 400: Master cylinder device 402: Input piston R23: Inter-piston chamber

Claims (7)

A master cylinder device for supplying pressurized hydraulic fluid to a brake device provided on a wheel,
A cylindrical housing with a closed front end;
A pressurizing piston having a stepped surface having a stepped surface facing forward at the outer periphery, and supplying hydraulic fluid pressurized to the brake device by its own advancement disposed in the housing;
An input piston disposed behind the pressurizing piston in the housing and connected to a brake operation member to advance by a driver's brake operation;
An inter-piston chamber defined between the input piston and the pressurizing piston;
The pressure piston is partitioned by the pressure piston and the housing in front of the stepped surface, and the pressure receiving area where the pressure of the hydraulic fluid inside the pressure piston acts on the pressure piston is the pressure of the hydraulic fluid inside the inter-piston chamber. A reaction force chamber made equal to the pressure receiving area acting on the pressure piston,
An inter-chamber communication passage communicating the inter-piston chamber and the reaction force chamber;
A forward force applying mechanism that applies one of the force generated by the electric motor and the force generated by the gas pressure to the pressurizing piston as a forward force that is a force for advancing it;
A master cylinder provided with a reaction force application mechanism that applies a force that opposes the advance of the input piston and that corresponds to the amount of advance to the input piston as an operation reaction force to the operation of the brake operation member. A device ,
In a normal state, the inter-piston chamber and the reaction force chamber are shut off from a low pressure source, and the inter-piston chamber and the reaction force chamber are communicated by the inter-chamber communication passage, so that the pressurizing piston is connected to the input piston. It is configured not to be moved by pressure changes in the inter-piston chamber and the reaction force chamber when being advanced, but to be moved by a forward force by the forward force applying mechanism, and
The reaction force applying mechanism is
The inter-piston chamber communicated by the inter-chamber communication passage, the liquid storage chamber communicating with the reaction force chamber, and the volume of the liquid storage chamber is increased in accordance with the amount of advance of the input piston. And an elastic reaction force against the liquid storage chamber that allows an elastic reaction force having a magnitude corresponding to an increase in the volume of the liquid storage chamber to act on the working fluid in the liquid storage chamber. A master cylinder device configured to include a force acting mechanism and configured to apply a force having a magnitude corresponding to an amount of advance of the input piston as an operation reaction force to the input piston . The forward force applying mechanism is
A rotating motor as the electric motor that rotates by generating electric power to generate a rotational force;
2. The master cylinder device according to claim 1, further comprising a rotational force conversion mechanism that converts rotational force generated by the rotational motor into the forward force. The rotational force conversion mechanism is
A nut that is rotatable by the rotational force of the rotary motor in a state in which it cannot move in the front-rear direction;
3. A master cylinder according to claim 2, further comprising: a plunger that is screwed with the nut in a non-rotatable state and abuts against the pressure piston by the rotational force of the rotary motor to advance the pressure piston. apparatus. The forward force applying mechanism is
A gas container in which a space filled with gas is formed inside the housing;
A partition that is disposed in the gas container and divides the gas container into an atmospheric pressure chamber that communicates with an atmospheric pressure source at the rear of the gas container and a negative pressure chamber that communicates with a negative pressure source at the front of the gas container. 2. A master cylinder device according to claim 1, further comprising: a plunger that abuts against the pressurizing piston by a pressure difference between a pressure in the atmospheric pressure chamber and a pressure in the negative pressure chamber to advance the pressurizing piston. .   5. The master cylinder device according to claim 4, wherein the gas container is formed in an annular shape around the plunger, and the partition of the plunger is formed in a bowl shape on the outer periphery of the plunger.   The master cylinder device according to any one of claims 1 to 5, further comprising an input piston relative advance prohibition mechanism that prohibits the relative advance of the input piston with respect to the pressurizing piston.   One of the pressure piston and the input piston has a bottomed hole that opens toward the other, and the other of the pressure piston and the input piston is fitted into the bottomed hole, The master cylinder device according to any one of claims 1 to 6, wherein the inter-piston chamber is formed in a bottomed hole.

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