JP5471913B2 - Cylinder device - Google Patents

Description

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

  In the hydraulic brake system, for example, a cylinder device as described in the following patent document may be employed. The cylinder device has a function of pressurizing brake fluid using pressure input from an external high-pressure source, and is a so-called master cylinder with a fluid pressure boost function.

JP 2008-24098 A

  When the above cylinder device is employed in a hybrid vehicle, a regenerative braking force can be used as a braking force. Therefore, it is necessary to prevent a hydraulic braking force from being generated even though the driver operates the operation member. In this case, it is desired that the operation feeling of the operation member is good. Further, in the case of a failure of the power supply system, etc., it is necessary to pressurize the brake fluid by the driver's operating force, so it is desirable that the brake fluid be efficiently pressurized at that time as well. Further, considering that the cylinder device is disposed in the vehicle, it is desired that the mountability is good, that is, the cylinder device is compact. From this point of view, there is still a lot of room for improvement in the cylinder device, and the practicality of the cylinder device can be improved by making various improvements.

  This invention is made | formed in view of the said situation, and makes it a subject to provide a highly practical cylinder apparatus.

  In order to solve the above-described problem, the cylinder device of the present invention can be simply described as an operation force-dependent pressurization state in which the brake fluid is pressurized by an operation force applied to the operation member, and an operation according to the operation amount of the operation member. A cylinder device that selectively realizes a high pressure source pressure dependent pressurizing state in which a brake fluid is pressurized depending on a pressure from a high pressure source while generating a reaction force, and an input piston and an intermediate piston are arranged in an inner chamber The input chamber into which the pressure from the high pressure source is input between the intermediate piston and the pressurizing piston is fitted in front of the flange portion provided at the rear end of the intermediate piston. Each of which has an annular chamber formed therein, a mechanism for applying an elastic force that opposes the relative movement between the input piston and the intermediate piston, a mechanism for switching the communication state between the annular chamber and the reservoir, and a communication state between the reservoir and the inner chamber and the reservoir. Communication with the, characterized in that a mechanism for switching the non-communicated state.

  According to the cylinder device of the present invention, as will be described in detail later, since the input piston and the intermediate piston are fitted together, the number of high-pressure seals that need to be engaged with the input piston can be reduced, and the friction resistance It is possible to reduce the influence of the operation member on the operation feeling. In addition, since the volume of the input chamber can be reduced to the extent that the pressure piston and the intermediate piston come into contact with each other when the operation member is not operated, it is possible to ensure a sufficient operation stroke of the operation member in the event of a failure. It becomes.

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.

  In each of the following items, (1) corresponds to claim 1, (2) corresponds to claim 2, (3) corresponds to claim 3, (6) corresponds to claim 4, (7) corresponds to claim 5, (8) corresponds to claim 6, and (9) and (10) correspond to claim 7, respectively.

(1) A cylinder device for supplying pressurized brake fluid to the brake device in order to operate the brake device provided on the wheel,
A cylindrical housing with a closed front end;
A pressurizing piston disposed in the housing such that a pressurizing chamber for pressurizing the brake fluid is defined in front of the housing;
An input chamber into which pressure from a high-pressure source is input in front of the main body portion, and a front portion of the main body portion; An intermediate piston disposed in the housing such that an annular chamber whose volume changes with advancement and retraction is defined;
An input piston that is fitted to the rear end of the intermediate piston and is connected to the operation member at the rear end of the intermediate piston so that an inner chamber whose volume changes with relative movement with the intermediate piston is partitioned; ,
With the relative movement of the input piston and the intermediate piston in the direction in which the volume of the internal chamber decreases, the elastic force is applied to the input piston and the intermediate piston in the direction opposite to the relative movement. Mechanism,
A first communication state switching mechanism that selectively realizes an annular chamber communication state in which the annular chamber and the reservoir communicate with each other and an annular chamber non-communication state in which the annular chamber does not communicate with each other;
A second communication state switching mechanism that selectively realizes an internal chamber communication state in which the internal chamber and the reservoir communicate with each other and an internal chamber non-communication state in which the internal chamber does not communicate with each other;
In the annular chamber non-communication state and the internal chamber communication state, the elastic movement is prohibited by allowing the intermediate piston to move forward while allowing the relative movement of the input piston and the intermediate piston with volume change of the internal chamber. The operation reaction force according to the operation amount of the operation member is generated based on the elastic force of the force applying mechanism, and the brake fluid in the pressurizing chamber according to the pressure from the high pressure source input to the input chamber Pressurization of
In the annular chamber communication state and the internal chamber non-communication state, the volume change of the internal chamber is prohibited, and the relative movement between the input piston and the intermediate piston is prohibited, while the pressure piston is in contact A cylinder device configured to allow pressurization of the brake fluid in the pressurizing chamber by an operation force applied to the operation member by allowing the intermediate piston to advance.

  In the cylinder device according to this aspect, the input piston and the intermediate piston are fitted so as to be relatively movable, and the volume of the two pistons is increased in accordance with the relative movement of the two pistons. A changing liquid chamber (inner chamber) is partitioned. When the relative movement is allowed such that the input piston moves forward with respect to the intermediate piston, an elastic force is generated by the elastic force applying mechanism so as to be a resistance to the relative movement. On the other hand, a liquid chamber (input chamber) into which pressure from a high-pressure source is input is formed in front of the intermediate piston by the pressurizing piston, and the intermediate piston is in sliding contact with the housing at the above-mentioned flange portion. An annular liquid chamber (annular chamber) is defined in front of the collar.

  In the normal state, if the annular chamber non-communication state is realized by the first communication state switching mechanism, the annular chamber is sealed and the forward movement of the intermediate piston is prohibited. If the internal chamber communication state is realized by the second communication state switching mechanism in that state, the internal chamber is brought to atmospheric pressure, and the input piston moves relative to the intermediate piston in a state where the elastic force is applied by the elastic force applying mechanism. Is acceptable. In this state, if pressure from a high pressure source is input to the input chamber, depending on the pressure, the pressurizing piston inputs the brake fluid in the liquid chamber (pressurizing chamber) formed in front of it. It will be in the state pressurized according to the pressure input into the chamber. At this time, the elastic force of the elastic force applying mechanism gives an operation reaction force corresponding to the operation amount of the operation member. That is, normally, an input from the high pressure source is applied regardless of the operation amount of the operation member while applying an operation reaction force according to the advance amount of the input piston, that is, the operation amount of the operation member to the operation member. A state in which the brake fluid in the pressurizing chamber is pressurized with a pressurizing force corresponding to the pressure (a high pressure source pressure dependent pressurizing state) is realized.

  By the way, in the high pressure source pressure dependent pressurization state, the sealed annular chamber is pressurized to a pressure corresponding to the operation reaction force, and the intermediate piston is prohibited from moving forward. In that sense, the annular chamber can also be called a reaction force chamber. In addition, the elastic force applying mechanism has a function of giving an operation reaction force corresponding to the operation amount to the operation member in a state where the input piston is allowed to advance with respect to the intermediate piston. To be.

  On the other hand, if the annular communication state is realized by the first communication switching mechanism in a failure where electric power is not supplied to the hydraulic brake system, that is, an electrical failure, the annular chamber becomes atmospheric pressure. The intermediate piston is allowed to advance. In that state, if the second communication state switching mechanism realizes the non-communication state of the internal chamber, the internal chamber is sealed, and relative movement between the input piston and the intermediate piston is prohibited, so that the input piston and the intermediate piston Is allowed to move forward. In this state, when the intermediate piston comes into contact with the pressure piston, the propulsive force of the input piston, that is, the operation force applied to the operation member is directly transmitted to the pressure piston. That is, a state where the brake fluid in the pressurizing chamber is pressurized depending on the operating force at the time of electrical failure (operating force dependent pressurizing state) is realized.

  In the cylinder device of this section, the input piston and the intermediate piston are fitted together. Therefore, the high pressure seal that needs to be engaged with the input piston to partition each liquid chamber is a housing that holds the input piston between the intermediate piston and the input piston, and the outer peripheral surface of the input piston and the input piston in a slidable manner. One piece may be provided between each of the two parts. Therefore, in the high pressure source pressure dependent pressurization state, the frictional resistance against the movement of the input piston is relatively small, and the influence of the frictional resistance on the operational feeling of the operating member, that is, the influence on the operational feeling of the brake operation can be reduced. Is possible.

  In the cylinder device of this section, the volume of the input chamber can be reduced to the extent that the pressurizing piston and the intermediate piston come into contact with each other in the non-operating state, that is, in the state where the operating member is not operated. This makes it possible to pressurize the brake fluid in the pressurizing chamber by an operating force applied to the operating member immediately after the operating member starts moving in the event of a failure. Therefore, according to the cylinder device of the aspect of this section, it is possible to sufficiently secure the operation range of the operation member, that is, the operation stroke in the event of failure.

(2) The second communication state switching mechanism is
The internal chamber communication path for communicating the internal chamber and the reservoir, and an open / close valve provided in the internal chamber communication path to open and close the communication path is described in (1). Cylinder device.

  The mode of this section is a mode in which a limitation is imposed on the structure of the second communication state switching mechanism.

(3) The intermediate piston is
Through two seals fitted to the outer peripheral surface of the main body portion of the intermediate piston at positions separated from each other in the front-rear direction, and in sliding contact with the inner peripheral surface of the housing; and the inner chamber; A first communication path that connects a piston-side port formed on the outer peripheral surface of the body portion of the intermediate piston at a position between the two seals;
The housing comprises:
A second communication path connected to the reservoir from a housing-side port formed on the inner peripheral surface of the housing at a position facing the portion between the two seals of the intermediate piston when the intermediate piston is not advanced. Have
The internal chamber communication path is configured including the first communication path and the second communication path, and the open / close valve is configured including the two seals, the piston side port, and the housing side port,
The second communication state switching mechanism is
The piston-side port and the housing-side port communicate with each other when the intermediate piston is not moving forward, thereby realizing the internal chamber communication state. The inner chamber non-communication state is realized by facing the outer peripheral surface of the intermediate piston at a position on the rear side of the two seals and not connecting the piston side port and the housing side port. The cylinder device according to (2), which is configured.

  The mode of this section is a mode in which the structure of the second communication state switching mechanism is specifically limited. In the aspect of this section, the second communication state switching mechanism is configured including the first communication path, the second communication path, the piston side port, and the housing side port. In brief, in the cylinder device of this section, a port communicating with the inner chamber is provided between two seals fitted to the intermediate piston, while a reservoir is provided on the inner peripheral surface of the housing in which the intermediate piston is in sliding contact. A port is provided in communication with the two ports so that the two ports face each other in an inoperative state, and a seal provided on the rear side of the two seals is provided in the housing as the intermediate piston advances. The second communication state switching mechanism is configured so that communication between the two ports is interrupted when the port passes.

  According to the cylinder device of this section, the internal chamber non-communication state can be realized immediately after the intermediate piston moves from the non-operating state by optimizing the arrangement positions of the two ports and the two seals. The above-described function of sufficiently securing the operation stroke of the operation member at the time of failure can be sufficiently ensured.

  In addition, it can be set as the 2nd communication state switching mechanism of a structure which attaches two seals to the inner peripheral surface of a housing, and provides the port by the side of the housing between these two seals, In the case of a mechanism having a simple structure, the inner chamber needs to be sealed in the entire process of moving the intermediate piston, and therefore a sealed chamber that seals the port on the intermediate piston side over the entire range of the movement of the intermediate piston is necessary. Become. On the other hand, in the cylinder device of this section, two seals are fitted to the intermediate piston, and a port on the intermediate piston side is provided between them, so that the intermediate piston is located at any position in its forward range. Even in such a case, the inner chamber can be sealed by a small space defined by the inner peripheral surface of the housing and the two seals. Therefore, according to the aspect of this item, the dimension in the moving direction of the intermediate piston of the cylinder device can be reduced, and the cylinder device can be made compact.

  (4) The cylinder device according to (2), wherein the on-off valve is an electromagnetic on-off valve.

(5) The on-off valve
A mechanical on-off valve that opens when the pressure of the hydraulic fluid in the annular chamber is introduced as a pilot pressure and the pilot pressure is equal to or higher than a set pressure, and closes when the pilot pressure falls below the set pressure The cylinder device according to item (2).

  The second communication state switching mechanism in the aspect of the above two terms differs from the second communication state switching mechanism in the previous item in the structure, particularly in the structure of the on-off valve. The former of the above two items is a mode in which the on-off valve is an electromagnetic on-off valve, and the electromagnetic on-off valve is considered to realize an internal chamber non-communication state at the time of electrical failure or the like. Is preferably a normally closed valve, that is, an on-off valve that is closed when de-energized and opened when excited. In the latter case, the internal chamber communication state and the non-communication state are switched depending on the pressure in the annular chamber. In the annular chamber non-communication state, the pressure in the annular chamber increases according to the operating force of the operating member. However, if the annular chamber is at atmospheric pressure in the annular chamber communication state, the latter mode Can be considered as a mode of realizing the internal chamber non-communication state on condition that the annular chamber communication state is realized.

  According to the second communication state switching mechanism in the aspect of the previous section, the internal chamber non-communication state is realized on the condition that the intermediate piston moves forward to some extent. For example, it is possible to realize a non-communicating state in the inner chamber in a state where the intermediate piston hardly advances. For example, when the pressure from the high pressure source becomes insufficient, such as an electrical failure, the cylinder device can realize the internal chamber non-communication state immediately after the operation of the operation member is started. Can also be constructed. Therefore, the inner chamber non-communication state is realized in a state where the operation member is hardly operated, and the operation force dependent pressurization state is realized. Therefore, even when an electrical failure occurs, the brake device does not generate a braking force even when the brake operation is started, i.e., the brake operation has almost no state such as idling, and the driver feels uncomfortable. The brakes can be operated without any trouble.

  Further, the aspects of the above two terms can be combined with the aspects of the previous term. That is, it is possible to construct a cylinder device that employs two types of second communication state switching mechanisms. Specifically, for example, in the aspect of the preceding paragraph, the electromagnetic on-off valve or the mechanical on-off valve is disposed in the second communication path or the communication path connecting the second communication path and the reservoir, and the on-off valve May be configured to open and close the communication path. By the way, if two second communication state switching mechanisms are provided, one of them will serve as a backup for the other, and a cylinder device that is excellent in terms of fail-safe will be realized.

  (6) The first communication state switching mechanism includes an annular chamber communication passage for communicating the annular chamber and the reservoir, and an on-off valve provided in the annular chamber communication passage for opening and closing the communication passage. The cylinder device according to any one of items (1) to (5), comprising:

  (7) The first communication state switching mechanism is provided in the annular chamber communication passage for communicating the annular chamber and the reservoir, and the annular chamber communication passage is provided with a pressure exceeding the set pressure. The cylinder device according to any one of items (1) to (5), including a relief valve that opens and closes the communication path in the event of a failure.

  The modes described in the above two terms are modes in which limitations relating to the configuration of the first communication state switching mechanism are added. The former on-off valve can be, for example, a normally-open electromagnetic on-off valve, that is, an on-off valve that is open in a non-excited state and closed in an excited state. By using such an on-off valve, an annular chamber communication state and an annular chamber non-communication state are selectively realized depending on whether or not electric power is supplied to the hydraulic brake system. Further, according to the aspect employing such an electromagnetic on-off valve, in the event of a failure, the movement of the intermediate piston is permitted from the start stage of operation of the operation member, and the operation force dependence is increased from that stage. A pressure state can be realized. On the other hand, according to the latter mode, when the operating force is applied to the operating member to some extent at the time of failure, the annular chamber communication state is realized. Generally, a relief valve is cheaper than an electromagnetic on-off valve, and according to the latter mode, a relatively inexpensive cylinder device is realized.

(8) The cylinder device is
A spring disposed in the internal chamber and acting on the input piston and the intermediate piston in a direction in which the volume of the internal chamber increases in its own elastic force;
The cylinder device according to any one of (1) to (7), wherein the elastic force applying mechanism includes the spring.

  The mode described in this section is a mode in which the structure of the elastic force applying mechanism is specifically limited. In the aspect of this section, the spring, which is a main component of the mechanism, is disposed in the internal chamber defined by the input piston and the intermediate piston. Therefore, the aspect of this term can be considered as an aspect in which a stroke simulator is incorporated in the cylinder device. In addition, since the stroke simulator is incorporated in the dead space called the internal chamber, according to the aspect of this section, a compact cylinder device is realized.

(9) The cylinder device is
Each functions as the spring, with one end supported by one of the input piston and the intermediate piston and the other end supported by the other of the input piston and the intermediate piston. Two springs arranged in series in the inner chamber and having different spring constants;
The two springs are sandwiched between one other end and the other other end, and are floatingly supported by the two springs, and the volume of the inner chamber is increased by the elastic force of the two springs. A floating seat connecting the two springs to act on the input piston and the intermediate piston in the direction of
The cylinder device according to (8), wherein the elastic force applying mechanism is configured to include the two springs and the floating seat.

  (10) When the input piston and the intermediate piston move relative to each other so that the relative movement exceeds a set amount, one of the input piston and the intermediate piston, the floating seat, The cylinder device according to the item (9), which is configured so that the amount of elastic deformation of one of the two springs does not increase by prohibiting the approach.

  The modes described in the above two terms are modes in which the elastic force applying mechanism has two springs. According to the latter aspect, the elastic force applying mechanism allows the elastic deformation of both of the two springs in the initial stage of the brake operation, and prohibits the elastic deformation of one of the two springs after the operation has progressed to some extent. Can be configured to. When the change in the operation reaction force with respect to the change in the operation amount is defined as the operation reaction force gradient, the operation reaction force gradient is small at the initial stage, and the operation reaction force gradient is increased after the operation has progressed to some extent. A stroke simulator with force characteristics can be realized. Further, by arbitrarily setting the spring constant difference between the two springs, it is possible to arbitrarily vary the difference between the initial operation reaction force gradient and the operation reaction force gradient at a stage where the operation has advanced to some extent. If the spring constant of the spring whose elastic deformation is prohibited when the operation has advanced to some extent is made smaller than the other spring constant, the difference in the operation reaction force gradient in the two stages can be made larger.

(11) The intermediate piston is in sliding contact with the inner peripheral surface of the housing via a seal fitted to the outer peripheral surface of the main body portion of the intermediate piston in front of the annular chamber.
The housing comprises:
The intermediate piston has a port that is provided on the inner peripheral surface of the housing at a position facing the front portion of the seal of the intermediate piston in a state where the intermediate piston is not advanced, and is connected to a communication passage communicating with the reservoir;
The intermediate chamber is configured so that the annular chamber communicates with the reservoir through the port when the intermediate piston moves forward to a position where the port faces the rear portion of the seal of the intermediate piston. The cylinder device according to any one of (10).

  The cylinder device according to this aspect can be considered as a device having another first communication state switching mechanism different from the first communication state switching mechanism. The other first communication state switching mechanism is configured such that when the intermediate piston moves forward by a set amount, that is, when the intermediate piston moves forward and the volume of the annular chamber becomes less than the set volume, the annular chamber and the reservoir are moved. Since it has a function of communicating, it can be considered as a volume-based communication mechanism.

  The aspect of this section is suitable for the cylinder device according to the previous aspect in which the first communication state switching mechanism is configured to include a relief valve. Since the first communication state switching mechanism including the relief valve realizes the annular chamber communication state when the pressure in the annular chamber exceeds the set pressure, it can be considered as a pressure-based communication mechanism. is there. As described above, the pressure in the annular chamber depends on the reaction force of the operation, and if the annular chamber communication state is realized only by the pressure-dependent communication mechanism, the annular chamber communication state is realized and the operation is performed. Even when pressurization of the pressurizing piston by force is allowed, an operation in a state where an operation reaction force according to the set pressure is received is required. This contributes to a loss that the operation force is used for other than the pressurization of the pressurizing piston at the time of failure. According to the aspect of this item, when the annular chamber communication state is realized by the first communication state switching mechanism serving as the pressure-dependent communication mechanism and the movement of the intermediate piston is permitted at the time of failure, the intermediate piston moves forward by the set distance. Thus, the annular chamber communication state is realized by the volume-based communication mechanism. In this state, the annular chamber is at atmospheric pressure, and the operating force applied to the operating member is effectively used for pressurization of the pressurizing piston.

  In this embodiment, the two seals and the two ports described above are arranged on the rear side of the two seals and function as the seal in the embodiment of this section. Of the two ports, the one provided in the housing can be configured to function as the port in the aspect of this section. With such a configuration, switching from the annular chamber non-communication state by the volume-based communication mechanism to the annular chamber communication state, and switching from the internal chamber communication state to the internal chamber non-communication state by the second communication switching mechanism, It is performed almost simultaneously.

(12) In the case where the pressurizing piston is a first pressurizing piston, a first pressurizing chamber, which is the pressurizing chamber, is partitioned between itself and the first pressurizing piston behind itself, and (1) to (11) including a second pressurizing piston disposed in the housing in front of the first pressurizing piston so as to define a second pressurizing chamber in front of itself. The cylinder device according to any one of the items.

  The cylinder device according to this aspect is a cylinder device having two pressure pistons and two pressure chambers. Such a cylinder device is relatively long in the pressurizing direction of the pressurizing piston, that is, in the direction in which the input piston advances and retreats. Therefore, the advantage of downsizing due to the arrangement of the stroke simulator inside the cylinder device is effectively utilized for the cylinder device having two pressure pistons and two pressure chambers.

It is a schematic diagram showing the drive system and braking system of a hybrid vehicle which mount the cylinder apparatus of the Example of claimable invention. It is a figure which shows the hydraulic brake system comprised including the cylinder apparatus of the Example of claimable invention. It is a graph which shows the relationship between the operation amount of the operation member connected with a cylinder apparatus, and the operation reaction force provided to an operation member from a cylinder apparatus. It is a figure which shows the hydraulic brake system comprised including the cylinder apparatus used as the 1st modification of an Example. It is a figure which shows the hydraulic brake system comprised including the cylinder apparatus used as the 2nd modification of an Example. It is a figure which shows the mechanical on-off valve employ | adopted as the cylinder apparatus of a 2nd modification. It is a figure which shows the hydraulic brake system comprised including the cylinder apparatus used as the 3rd modification of an Example.

  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 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. These engine 10, electric motor 12, and generator 14 are connected to each other by a power split mechanism 16. By controlling the power split mechanism 16, the output of the engine 10 is divided into an output for operating the generator 14 and an output for rotating one of the four wheels 18 as a driving wheel, The output from the electric motor 12 can be transmitted to the drive wheels. That is, the power split mechanism 16 functions as a transmission related to the driving force transmitted to the drive wheels via the speed reducer 20 and the drive shaft 22. It should be noted that some components such as “wheel 18” are used as a general term, but when indicating that they correspond to any of the four wheels, the left front wheel, the right front wheel, the left rear wheel, The subscripts “FL”, “FR”, “RL”, and “RR” are assigned to the right rear wheel, respectively. According to this notation, the driving wheels in the vehicle are the wheel 18RL and the wheel 18RR.

  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, one of which is used mainly as an electric motor 12 for outputting a driving force, and the other is a generator 14. As mentioned above, it is mainly used for generating electricity 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 18RL and 18RR as the vehicle travels. At this time, in the electric motor 12 connected to the wheels 18RL and 18RR, 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, the vehicle is braked by controlling the regenerative brake together with the engine brake and a 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 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 40 has a function of supervising these controls. For example, the hybrid vehicle can run 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 40. . Specifically, the distribution of the output of the engine 10 and the output of the electric motor 12 is determined by the main ECU 40, and the engine ECU 42 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 44.

  A battery ECU 46 that controls the battery 26 is also connected to the main ECU 40. The battery ECU 46 monitors the state of charge of the battery 26, and outputs a charge request command to the main ECU 40 when the amount of charge is insufficient. The main ECU 40 that has received the charge request command outputs a power generation command from the generator 14 to the motor ECU 44 in order to charge the battery 26.

  The main ECU 40 is also connected to a brake ECU 48 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 48 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 40. The main ECU 40 outputs this target braking force to the motor ECU 44, and the motor ECU 44 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 40. Output to. In the main ECU 40, the regenerative braking force is subtracted from the target braking force, and the target hydraulic braking force to be generated in the hydraulic brake system 100 mounted on the vehicle is determined by the subtracted value. The main ECU 40 outputs the target hydraulic braking force to the brake ECU 48, and the brake ECU 48 performs control so that the hydraulic braking force generated by the hydraulic brake system 100 becomes the target hydraulic braking force.

≪Configuration of hydraulic brake system≫
The hydraulic brake system 100 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, the character [] is a symbol used when a sensor or the like is shown in the drawings.

  FIG. 2 schematically shows a hydraulic brake system 100 provided in the vehicle. The hydraulic brake system 100 has a cylinder device 110 for pressurizing brake fluid. The driver of the vehicle can operate the cylinder device 110 by operating the operation device 112 connected to the cylinder device 110, and the cylinder device 110 pressurizes the brake fluid by its own operation. The pressurized brake fluid is supplied to a brake device 116 provided on each wheel via an antilock device 114 connected to the cylinder device 110. The brake device 116 generates a force for stopping the rotation of the wheel 18, that is, a hydraulic braking force, depending on the pressure of the pressurized brake fluid (hereinafter referred to as “output pressure”).

  The hydraulic brake system 100 has an external high pressure source device 118 for increasing the pressure of the brake fluid. The external high pressure source device 118 is connected to the cylinder device 110 via the pressure increasing / decreasing device 120. The pressure increasing / decreasing device 120 is a device that controls the pressure of the brake fluid that has been increased in pressure by the external high pressure source device 118, and increases the pressure of the brake fluid input to the cylinder device 110 (hereinafter referred to as "input pressure"). And reduce. The cylinder device 110 is configured to be operable by increasing or decreasing the input pressure. The hydraulic brake system 100 has a reservoir 122 that stores brake fluid under atmospheric pressure. The reservoir 122 is connected to each of the cylinder device 110, the pressure increasing / decreasing device 120, and the external high pressure source device 118.

  The operation device 112 includes a brake pedal 150 as an operation member, and an operation rod 152 connected to the brake pedal 150. The brake pedal 150 is rotatably held on the vehicle body. The operation rod 120 is connected to the brake pedal 150 at the rear end, and is connected to the cylinder device 110 at the front end. The operation device 112 includes an operation amount sensor [SP] 156 for detecting the operation amount of the brake pedal 150 and an operation force sensor [FP] 158 for detecting the operation force. The operation amount sensor 156 and the operation force sensor 158 are connected to the brake ECU 48, and the brake ECU 48 determines a target braking force based on detection values of these sensors.

  The brake device 116 is connected to the cylinder device 110 via the liquid passages 200 and 202. These fluid passages 200 and 202 are fluid passages for supplying the brake fluid pressurized to the output pressure by the cylinder device 110 to the brake device 116. An output pressure sensor [Po] 204 is provided in the liquid passage 202. Although not described in detail, each brake device 116 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 200 and 202 are connected to the brake cylinder of each brake device 116 via the antilock device 114. Incidentally, the fluid passage 200 is connected to the brake devices 116FL and 116FR on the front wheel side, and the fluid passage 202 is connected to the brake devices 116RL and 116RR on the rear wheel side. The brake cylinder presses the brake pad against the brake disc depending on the output pressure of the brake fluid pressurized by the cylinder device 110. Due to the friction generated by the pressing, each brake device 116 generates a hydraulic braking force that stops the rotation of the wheel, and the vehicle is braked.

  The anti-lock device 114 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 brake fluid from the cylinder device 110 to the brake device 116, and the pressure reducing on / off valve allows the brake fluid to flow from the brake device 116 to the reservoir. And it is comprised so that the lock | rock of a wheel may be cancelled | released.

  The external high-pressure source device 118 is provided in the liquid passage from the reservoir 122 to the pressure increasing / decreasing device 120. The external high-pressure source device 118 includes a hydraulic pump 300 that increases the hydraulic pressure of the brake fluid, and an accumulator 302 that stores the increased brake fluid. Incidentally, the hydraulic pump 300 is driven by a motor 304. In addition, the external high-pressure source device 118 includes a high-pressure source pressure sensor [Pi] 306 for detecting the pressure of the brake fluid that is set to a high pressure. The brake ECU 48 monitors the detected value of the high-pressure source pressure sensor 306, and the hydraulic pump 300 is controlled and driven based on the detected value. With this control drive, the external high-pressure source device 118 always supplies brake fluid having a pressure equal to or higher than the set pressure to the pressure increasing / decreasing device 120.

  The pressure increasing / decreasing device 120 includes an electromagnetic pressure increasing linear valve 250 that increases the input pressure and an electromagnetic pressure reducing linear valve 252 that decreases the input pressure. The pressure increasing linear valve 250 is provided in the middle of the liquid passage from the external high pressure source device 118 to the cylinder device 110. On the other hand, the pressure-reducing linear valve 252 is provided in the middle of the liquid passage from the reservoir 122 to the cylinder device 110. Note that each fluid passage connected to the cylinder device 110 of the pressure-increasing linear valve 250 and the pressure-reducing linear valve 252 is a single fluid passage and is connected to the cylinder device 110. Further, an input pressure sensor [Pc] 256 for detecting the input pressure is provided in the liquid passage. The brake ECU 48 controls the pressure increase / decrease device 120 based on the detection value of the input pressure sensor 256.

  The pressure-increasing linear valve 250 is closed in a state where no current is supplied, that is, in a non-excited state, and by supplying current thereto, that is, in an excited state, The valve opens at the valve opening pressure corresponding to the supplied current. Incidentally, the valve opening pressure increases as the supplied current increases. On the other hand, the pressure-reducing linear valve 252 is opened when no current is supplied, and the maximum current in the set range is supplied during normal operation, that is, when power can be supplied to the system. When the valve is closed and the supplied current is reduced, the valve is opened at the valve opening pressure corresponding to the current. Incidentally, the valve opening pressure is configured to decrease as the current decreases.

≪Configuration of cylinder device≫
As shown in FIG. 2, the cylinder device 110 includes a housing 400 that is a housing of the cylinder device 110, a first pressure piston 402 and a second pressure piston 404 that pressurize brake fluid supplied to the brake device 116, The intermediate piston 406 moves forward by the pressure input from the external high pressure source device 118 and the input piston 408 to which the operation of the driver is input through the operating device 112 is configured. FIG. 2 shows a state where the cylinder device 110 is not operating, that is, a state where the brake operation is not performed. Incidentally, as is the case with a general cylinder device, this cylinder device 110 also communicates several fluid chambers in which brake fluid is stored, between those fluid chambers, and between these fluid chambers and the outside. Several communication passages are formed, and several seals are arranged between the components in order to ensure liquid tightness. These seals are general, and in consideration of the simplification of the description of the specification, the description thereof will be omitted unless particularly described.

  The housing 400 is mainly composed of two members, specifically, a first housing member 410 and a second housing member 412. The first housing member 410 has a generally cylindrical shape with the front end closed, and a flange 420 is formed on the outer periphery of the rear end. The first housing member 410 is fixed to the vehicle body at the flange 420. The first housing member 410 has three portions having different inner diameters, specifically, a front small diameter portion 422 having the smallest inner diameter located on the front side, and a rear large diameter portion 424 having the largest inner diameter located on the rear side. The intermediate portion 426 is located between the front small-diameter portion 422 and the rear large-diameter portion 424 and has an intermediate inner diameter between them.

  The second housing member 412 has a cylindrical shape having a front large-diameter portion 430 having a large outer diameter located on the front side and a rear small-diameter portion 432 having a small outer diameter located on the rear side. The second housing member 412 has a front end portion of the front large-diameter portion 430 at the rear large-diameter portion 424 in a state where a gap is provided in a step surface between the intermediate portion 426 and the rear large-diameter portion 424 of the first housing member 410. It is inserted. The first housing member 410 and the second housing member 412 are fastened to each other by a lock ring 434 fitted on the inner peripheral surface of the rear end portion of the first housing member 410.

  Each of the first pressurizing piston 402 and the second pressurizing piston 404 has a bottomed cylindrical shape whose rear end is closed, and is slidably fitted to the front small-diameter portion 422 of the first housing member 410. Are combined. The first pressure piston 402 is disposed behind the second pressure piston 404. Between the first pressurizing piston 402 and the second pressurizing piston 404, there is a first pressurizing chamber R21 for pressurizing the brake fluid supplied to the brake devices 116RL, RR provided on the two rear wheels. A second pressurizing chamber R22 for pressurizing the brake fluid supplied to the brake devices 116FL and FR provided in the two front wheels is defined in front of the second pressurizing piston 404. Is formed. The first pressure piston 402 and the second pressure piston 404 are fixed to the headed pin 460 erected at the rear end portion of the first pressure piston 402 and the rear end surface of the second pressure piston 404. The separation distance is limited within the set range by the pin holding cylinder 462 provided. In addition, compression coil springs (hereinafter sometimes referred to as “return springs”) 464 and 466 are disposed in the first pressurizing chamber R21 and the second pressurizing chamber R22, respectively. The first pressurizing piston 402 and the second pressurizing piston 404 are biased in the direction in which they are separated from each other, and the second pressurizing piston 404 is biased rearward.

  The intermediate piston 406 has a shape having a bottomed cylindrical body 470 whose front end is closed and whose rear end is open, and a flange 472 provided at the rear end of the main body 470. Has been. The intermediate piston 406 is disposed behind the first pressurizing piston 402, the front part of the main body part 470 is on the rear side of the inner peripheral surface of the front small diameter part 422 of the first housing member 410, and the flange part 472 is intermediate. The inner peripheral surface of the part 426 is slidably fitted.

  In front of the intermediate piston 406, between the rear end portion of the first pressurizing piston 402, a fluid chamber to which brake fluid is supplied from the external high pressure source device 118, that is, pressure from the high pressure source device 118 is input. A liquid chamber (hereinafter may be referred to as “input chamber”) R23 is defined. Incidentally, in FIG. 2, it is shown in the almost collapsed state. In addition, a space formed between the inner peripheral surface of the second housing member 412 and the outer peripheral surface of the main body portion 470 of the intermediate piston 406 exists inside the housing 400. The space is partitioned by a front end surface of the flange portion 472 of the intermediate piston 406 and a step surface between the front small-diameter portion 422 and the rear large-diameter portion 424 of the first housing member 410, so that an annular liquid chamber (hereinafter referred to as an annular liquid chamber). R24) may be formed. Further, at the rear of the flange 472, the volume increases with the forward movement of the intermediate piston 406 between the front end of the second housing member 412 and the liquid chamber (hereinafter referred to as the same pressure as the input chamber R23). R25 is defined as a compartment.

  The input piston 408 has a cylindrical shape with a front end opened and a rear portion closed. The input piston 408 is inserted into the housing 400 from the rear end side of the housing 400 while being in sliding contact with the inner peripheral surface of the second housing member 412, and is inserted into the intermediate piston 406. It can be moved relative to the input piston 408. More specifically, an annular seal holder 474 is fixedly attached to the rear end portion of the inner peripheral surface of the intermediate piston 406, and the input piston 408 is interposed via a seal held by the seal holder 474. Thus, the intermediate piston 406 can be advanced and retracted while being in sliding contact with the inner peripheral surface of the intermediate piston 406. Inside the input piston 408 and the intermediate piston 406 configured as described above, a liquid chamber (hereinafter, also referred to as “internal chamber”) R26 whose volume changes due to the relative movement of the intermediate piston 406 and the input piston 408 is provided. Is partitioned. Incidentally, the range of relative movement between the input piston 408 and the intermediate piston 406 is that the front end portion of the input piston 408 is locked by the stepped surfaces provided on the inner peripheral surface of the seal holder 474 and the intermediate piston 406, respectively. Limited. Further, the backward movement of the intermediate piston 406 is also restricted by the seal holder 474 coming into contact with the front end surface of the second housing member 412.

  In the internal chamber R26, a first reaction force spring 480 and a second reaction force spring 482, which are two compression coil springs, are disposed between the inner bottom surface of the intermediate piston 406 and the inner bottom surface of the input piston 408. . The first reaction force spring 480 is arranged in series behind the second reaction force spring 482, and a rod-shaped floating seat 484 with a hook is sandwiched between the reaction force springs and is supported in a floating manner. The front end portion of the first reaction force spring 480 is supported by the seat surface on the rear side of the floating seat 484, and the rear end portion is supported by the rear end portion of the input piston 408. The second reaction force spring 482 has a front end portion supported by the rear end portion of the intermediate piston 406 and a rear end portion supported by the front seat surface of the floating seat 484. The first reaction force spring 480 and the second reaction force spring 482 arranged in this way cause the input piston 408 and the intermediate piston 406 to move away from each other, that is, the volume of the internal chamber R26 increases. Energized in the direction. The cylinder device 110 includes an elastic force applying mechanism constituted by a first reaction force spring 480 and a second reaction force spring 482, that is, a direction in which the input piston 408 and the intermediate piston 406 approach each other by the spring reaction force, That is, a mechanism is provided that imparts to the input piston 408 and the intermediate piston 406 an elastic force that opposes the relative movement between the input piston 408 and the intermediate piston 406 in a direction in which the volume of the internal chamber R26 decreases. Further, a buffer rubber 486 is fitted into the rear end portion of the floating seat 484, and the buffer rubber 486 abuts against the rear end surface of the input piston 408, so that the floating seat 484 and the input piston 408 are close to each other. Limited to range.

  An operation rod 152 is provided at the rear end of the input piston 408 so as to transmit the operation force applied to the brake pedal 150 to the input piston 408 and to move the input piston 408 forward and backward according to the operation amount of the brake pedal 150. The front ends of the are connected. A circular support plate 492 is attached to the operation rod 152, and a boot 494 is passed between the support plate 492 and the housing 400 to prevent dust at the rear of the cylinder device 110.

  The first pressurizing chamber R21 communicates with a liquid passage 202 connected to the antilock device 114 through a communication hole 500 whose opening serves as an output port, and a communication hole 502 provided in the first pressurizing piston 402 and The opening communicates with the reservoir 122 through a communication hole 504 serving as a drain port in a state where it is allowed to be non-communication. On the other hand, the second pressurizing chamber R22 communicates with the liquid passage 200 connected to the antilock device 114 via a communication hole 506 whose opening serves as an output port, and a communication hole provided in the second pressurizing piston 404. 508 and a communication hole 510 whose opening serves as a drain port communicate with the reservoir 122 in a state where it is allowed to be non-communication.

  The first pressurizing piston 402 has an outer diameter that is somewhat smaller than the inner diameter of the front small-diameter portion 422 of the first housing member 410, and a liquid passage 512 having a certain flow passage area is formed between them. . Further, the first housing member 410 is formed with a liquid passage 514 that communicates from the inner periphery of the front small diameter portion 422 to the stepped surface between the intermediate portion 426 and the rear large diameter portion 424. The input chamber R23 is connected to the pressure increasing / decreasing device 120 via the liquid passages 512 and 514, the back chamber R25, and a communication hole 516 whose opening serves as a connection port.

  The annular chamber R24 can communicate with the outside through a communication hole 518 whose opening serves as a connection port. The communication hole 518 is connected to a communication hole 522 whose opening is a connection port by an external communication path 520. The communication hole 522 is connected to the communication hole 504 via a liquid passage formed between the outer peripheral surface of the first pressurizing piston 402 and the inner peripheral surface of the front small diameter portion 422 of the first housing member 410. It communicates with the reservoir 122 via the communication path. In other words, the communication hole 518, the external communication path 520, the communication hole 522, and the communication hole 504 form an annular chamber communication path that connects the annular chamber R24 to the reservoir 122. The external communication path 520 is provided with an electromagnetic on-off valve 524, and the on-off valve 524 opens and closes the annular chamber communication path. The cylinder device 110 having such a structure includes a mechanism including an annular chamber communication path and an on-off valve 524, that is, an annular chamber that does not communicate with the annular chamber communication state in which the annular chamber R24 and the reservoir 122 communicate with each other. A first communication state switching mechanism that selectively realizes the non-communication state is provided. A pressure sensor [Pr] 526 for detecting the pressure of the brake fluid in the annular chamber R24 is provided between the on-off valve 524 and the communication hole 518.

  The intermediate piston 406 is provided with a communication hole 528 whose opening provided on the outer peripheral surface thereof is the piston-side port P1. The communication hole 528 is connected to the internal chamber R 26, and one communication path (hereinafter sometimes referred to as “first communication path”) is formed by the communication hole 528. In addition, annular seals 530F and 530R are fitted into the outer peripheral surface of the intermediate piston 802 and before and after the communication hole 528 at a relatively small interval. In addition, a communication path 532 is formed in the wall of the first housing member 410. One end of the communication path 532 is connected to the communication hole 522, and the other end is an inner periphery of the rear end portion of the front small-diameter portion 422. Open to the surface. This opening is a housing side port P2. The communication path 532 is connected to the reservoir 122 via a communication hole 522 and a communication hole 504, and one communication path (hereinafter, “second communication path”) is connected by the communication path 532, the communication hole 522, and the communication hole 504. May be formed). Therefore, the internal chamber R26 can communicate with the reservoir 122 via the internal chamber communication path including the first communication path and the second communication path.

  Even when high-pressure brake fluid is supplied from the external high-pressure source device 118 to the input chamber R23 and the back chamber R25 via the pressure increasing / reducing device 120, the intermediate piston 406 is not moved forward / backward. More specifically, the pressure receiving area at the front end of the main body portion 470 that defines the input chamber R23 and the pressure receiving area at the rear end of the flange portion 472 that defines the back chamber R25 are substantially equal to each other. The intermediate piston 406 is prevented from moving back and forth by balancing the force for moving the piston 406 backward with the force for moving the intermediate piston 406 forward by the pressure in the back chamber R25.

≪Cylinder unit operation≫
Hereinafter, the operation of the cylinder device 110 will be described. For convenience, the operation in the case of an electrical failure, that is, in the case where the power supply to the hydraulic brake system 100 is cut off, will be described before explaining the normal operation. Will be explained. At the time of failure, the pressure-increasing linear valve 250 and the pressure-reducing linear valve 252 are in a closed state and an open state, respectively, and the on-off valve 524 is in an open state, so that the first An annular chamber communication state in which the annular chamber R24 and the reservoir 122 communicate with each other is realized by the communication state switching mechanism.

  When the driver starts to depress the brake pedal 150 at the time of failure, the input piston 408 starts moving forward. At the start of the stepping operation, the intermediate piston 406 is not yet moved forward, and the piston side port P1 and the housing side port P2 face each other between the seal members 530F and 530R. That is, the piston side port P1 and the housing side port P2 are in communication with each other, and an internal chamber communication state in which the internal chamber R26 and the reservoir 122 are in communication is realized. In this state, the input piston 408 moves forward with respect to the intermediate piston 406 while contracting the first reaction force spring 480 and the second reaction force spring 482, and at this time, the volume of the internal chamber R26 is set to the brake of the internal chamber R26. The liquid flows out into the reservoir 122 and decreases.

  Soon after the input piston 408 advances, the intermediate piston 406 is advanced by the spring reaction forces of the first reaction force spring 480 and the second reaction force spring 482. When the seal 530R passes through the housing side port P2 due to the advance of the intermediate piston 406, the communication between the piston side port P1 and the housing side port P2 is cut off, and the internal chamber non-communication state is realized. Therefore, the volume change of the internal chamber R26 is prohibited, the relative movement between the input piston 408 and the intermediate piston 406 is prohibited, and the input piston 408 and the intermediate piston 406 are advanced together. In view of the fact that the internal chamber non-communication state is realized in this way, the piston side port P1, the housing side port P2, and the seal members 530F and 530R constitute an on-off valve capable of opening and closing the internal chamber communication passage. Can be considered. The cylinder device 110 includes an opening / closing valve and an internal chamber communication path. The internal chamber R26 and the reservoir 122 communicate with each other by opening / closing the internal chamber communication path using the opening / closing valve. A second communication state switching mechanism that selectively realizes the communication state and the non-communication state of the internal chamber that does not communicate is provided.

  As the intermediate piston 406 moves forward, the intermediate piston 406 moves the first pressurizing piston 402 forward while remaining in contact with the first pressurizing piston 402. Further, since the internal chamber non-communication state is realized, the input piston 408 and the intermediate piston 406 are integrated, and the operating force applied to the brake pedal 150 is directly transmitted to the first pressurizing piston 402. Will be. Therefore, the driver can push the first pressurizing piston 402 with his / her own force. As a result, the first pressurizing piston 402 moves forward, the transmission between the first pressurizing chamber R21 and the reservoir 122 is cut off, and the brake fluid in the first pressurizing chamber R21 is applied by the operating force applied to the brake pedal 150. It is pressed. Incidentally, with the pressurization of the first pressurizing chamber R21, the second pressurizing piston 404 also moves forward, and the communication between the second pressurizing chamber R22 and the reservoir 122 is cut off similarly to the first pressurizing chamber R21. The brake fluid in the second pressurizing chamber R22 is also pressurized. In this way, an operation force-dependent pressurization state in which the brake fluid in the first pressurizing chamber R21 and the second pressurizing chamber R22 is pressurized by the operating force applied to the brake pedal 150 is realized, and the brake device 116 is The hydraulic pressure corresponding to the driver's operating force is input.

  When the driver finishes the braking operation, that is, when the application of the operating force to the brake pedal 150 is released, the first pressurizing piston 402, the second pressurizing piston 404, and the intermediate piston 406 are connected to the return spring 464, 466 is returned to the initial position (the position shown in FIG. 2 where the rear end of the intermediate piston 406 is in contact with the front end of the second housing member 412). Further, the input piston 408 is moved to the initial position (the position shown in FIG. 2 by the first reaction force spring 480 and the second reaction force spring 482 together with the operation rod 152, and the front end portion is locked by the seal holder 474. Position).

  Next, the normal operation will be described. In the normal state, the on-off valve 524 is excited and closed, so that the first communication state switching mechanism realizes an annular chamber non-communication state in which the annular chamber R24 and the reservoir 122 do not communicate with each other, and the annular chamber R24. Is sealed, and the forward movement of the intermediate piston 406 is prohibited. In this state, even if the brake operation is performed and the input piston 408 is moved forward, the forward movement of the intermediate piston 406 is prohibited, so that the internal chamber R26 and the reservoir 122 are communicated by the second communication state switching mechanism. The internal room communication state is maintained. In normal times, unlike the case of the above-described failure, the input piston 408 is allowed to advance relative to the intermediate piston 406. When the input piston 408 moves forward, the elastic force exerted on the input piston 408 by the elastic force application mechanism, that is, the first reaction force spring 480 and the second reaction force spring 482 acts as a resistance force. The elastic force acts as an operation reaction force with respect to the operation of the brake pedal 150.

  FIG. 3 is a graph showing the change in the operation reaction force with respect to the forward movement amount of the input piston 408, that is, the operation amount of the brake pedal 150 (hereinafter, sometimes referred to as “operation reaction force gradient”). In other words, the operation reaction force characteristics of the cylinder device 110 are graphs. As can be seen from this figure, when the operation amount of the brake pedal 150 increases, the operation reaction force increases accordingly. When the operation amount of the brake pedal 150 increases beyond a set amount (hereinafter sometimes referred to as “reaction force gradient change operation amount”), the change in the operation reaction force with respect to the change in the operation amount increases. In other words, the increase gradient of the operation reaction force is increased.

  The change in the operation reaction force having the characteristics shown in FIG. 3 is caused when the operation amount of the brake pedal 150 exceeds the reaction force gradient change operation amount, that is, when the advance amount of the input piston 408 exceeds the set amount. This is realized by preventing the pressure applied by the first reaction force spring 480, which is one of the two reaction force springs 480 and 482, from increasing. In the cylinder device 110, the spring constant of the first reaction force spring 480 is considerably smaller than the spring constant of the second reaction force spring 482. Therefore, in the range where the operation amount is relatively small, the change in the operation reaction force with respect to the change in the operation amount is considerably small. More specifically, the first reaction force spring 480 and the second reaction force spring 482 are both compressed and deformed within a relatively small range of operation. On the other hand, when the operation amount exceeds the reaction force gradient change operation amount, the buffer rubber 486 comes into contact with the rear end portion of the input piston 408, and the first reaction force spring 480 does not elastically deform, and the second reaction force spring. Only 482 is elastically deformed. With such a mechanism, when the brake pedal 150 is operated beyond the set amount, the increase gradient of the operation reaction force is increased. Due to such operational reaction force characteristics, the operational feeling of the brake pedal 150 is improved.

  As described above, in this vehicle, the hydraulic brake system 100 may generate the hydraulic braking force by an amount that exceeds the regenerative braking force of the target braking force. Extremely speaking, as long as the target braking force can be covered by the regenerative braking force, the hydraulic braking force by the hydraulic brake system 100 is not required. The cylinder device 110 is configured to generate an operation reaction force according to the operation amount of the brake pedal 150 without depending on the hydraulic braking force to be generated in a normal state. Speaking extremely, the cylinder device 110 has a function of allowing the operation of the brake pedal 150 in a state in which the brake fluid is not pressurized by the first pressure piston 402 and the second pressure piston 404. . That is, the cylinder device 110 has a stroke simulator suitable for a hybrid vehicle.

  When pressurizing the brake fluid in the first pressurizing chamber R21 and the second pressurizing chamber R22 by the first pressurizing piston 402 and the second pressurizing piston 404 in order to generate the hydraulic braking force during the braking operation. The pressure generated by the high pressure source device 118 may be input to the input chamber R23. Specifically, the pressure controlled by the pressure increasing / decreasing device 120 may be input to the input chamber R23 so that the hydraulic braking force exceeding the regenerative braking force can be obtained. If the maximum regenerative braking force that can be obtained by regenerative braking in this vehicle is defined as the maximum usable regenerative braking force, it is assumed that the hydraulic braking force is generated when the target braking force exceeds the maximum usable regenerative braking force. In this case, the operation amount of the brake pedal at the time when generation of the hydraulic braking force is started is generally the maximum regeneration hydraulic braking start operation amount in FIG. In the hydraulic brake system 100, the maximum regenerative hydraulic braking start operation amount is set to be slightly larger than the reaction force gradient change operation amount described above. Incidentally, even if the target braking force does not exceed the maximum available regenerative braking force due to the amount of charge of the battery 26, etc., the hydraulic braking force may be required. The pressure from the high pressure source device 118 may be input to the input chamber R23 at a stage that does not reach the hydraulic fluid braking start operation amount.

  When pressure is input to the input chamber R23, the first pressurizing piston 402 moves forward without depending on the operation force applied to the brake pedal 150 and without depending on the operation amount. The brake fluid in the first pressurizing chamber R21 is pressurized. Accordingly, the brake fluid in the second pressurizing chamber R22 is also pressurized by the second pressurizing piston 404. That is, regardless of the forward movement of the input piston 408, there is a high pressure source pressure dependent pressurization state in which the brake fluid is pressurized in the first pressurizing chamber R21 and the second pressurizing chamber R22 depending on the pressure from the high pressure source. Realized. The braking force by the cylinder device 110, that is, the hydraulic braking force is determined by the input brake fluid pressure. The input pressure is controlled by the pressure increasing / decreasing device 120, and a required pressure is input to the input chamber R23.

  Even during normal times, when the operation of the brake pedal 150 is terminated, the pressure-reducing linear valve 252 is opened, and the first pressure piston 402 and the second pressure piston 404 are respectively returned by return springs 464 and 466. The input piston 408 is returned to the initial position by the first reaction force spring 480 and the second reaction force spring 482.

≪Features of this cylinder device≫
Since the cylinder device 110 has a structure in which the input piston 408 and the intermediate piston 406 are fitted together, the number of high-pressure seals that need to be engaged with the input piston 408 is reduced. Specifically, only two seals 540 and 542 shown in FIG. 2 are high pressure seals that engage the input piston 408. Therefore, in the high pressure source dependent pressurizing state, the frictional resistance against the movement of the input piston 408 is relatively small, and the influence of the frictional resistance on the operational feeling of the brake pedal 150, that is, the influence on the operational feeling of the brake operation is reduced. ing.

  In the present cylinder device 110, in a state where the brake pedal 150 is not operated, the volume of the input chamber R23 is reduced to the extent that the first pressurizing piston 402 and the intermediate piston 406 come into contact with each other. Immediately after the operation of the brake pedal 150 is started, the brake fluid in the first pressurizing chamber R21 and the second pressurizing chamber R22 is pressurized by an operating force applied to the brake pedal 150. That is, at the time of failure, the operation range of the brake pedal 150, that is, the operation stroke is sufficiently ensured.

  Further, in the present cylinder device 110, the above-described mechanism is adopted as a mechanism for realizing the internal chamber non-communication state. That is, two seal members 530F and 530R are fitted to the intermediate piston 406, the piston side port P1 is provided therebetween, and the communication between the piston side port P1 and the housing side port P2 is cut off as the intermediate piston 406 moves. It is configured to be. With such a configuration, the intermediate piston 406 is defined by the inner peripheral surface of the first housing member 410 and the two seal members 530F and 530R, regardless of whether the intermediate piston 406 is located at any position in the advance range thereof. The internal chamber R26 is sealed by the space. Therefore, the dimension in the moving direction of the intermediate piston 406 of the cylinder device 110 is reduced, and the size reduction is achieved.

  Further, in the cylinder device 110, the first reaction force spring 480 and the second reaction force spring 482 are disposed in an internal chamber R26 that is defined by the input piston 408 and the intermediate piston 406. Therefore, since the stroke simulator is incorporated in the cylinder device 110 and the stroke simulator is incorporated in the dead space of the internal chamber R26, a compact cylinder device is realized.

<< Modification 1 >>
FIG. 4 shows a hydraulic brake system 100 that employs a modified cylinder device 570 instead of the cylinder device 110 of the embodiment. In the cylinder device 570, a relief valve 572 is employed instead of the on-off valve 524 in the cylinder device 110 of the embodiment, and the pressure sensor 526 is omitted. Other structures are the same as those in the embodiment. In the following description of the modified example, only the configuration and operation of the cylinder device 570 different from those of the cylinder device 110 of the embodiment will be described for the sake of simplicity.

  In the cylinder device 570, the first communication state switching mechanism is configured to include a relief valve 572 and an annular chamber communication passage that communicates the annular chamber R24 with the reservoir 122. When the brake pedal 150 is not operated, the relief valve 572 is closed. That is, the first communication state switching mechanism realizes the annular chamber non-communication state, and the annular chamber R24 is sealed. When the driver depresses the brake pedal 150, the input piston 408 starts moving forward, and the spring reaction forces of the first reaction force spring 480 and the second reaction force spring 482 increase. Due to these spring reaction forces, a forward force is applied to the intermediate piston 406, and the brake fluid in the annular chamber R24 is pressurized by the flange 472 of the intermediate piston 406. When the pressure of the pressurized brake fluid in the annular chamber R24 reaches the valve opening pressure of the relief valve 572, the relief valve 572 is opened, and the brake fluid in the annular chamber R24 flows into the reservoir 122 and the intermediate piston 406 Will move forward. That is, the first communication state switching mechanism can be considered as a pressure-based communication mechanism that realizes the annular chamber communication state based on the set pressure of the relief valve 572.

  The valve opening pressure of the relief valve 572 is set to the pressure of the annular chamber R24 when the operation amount of the brake pedal 150 becomes the set operation amount when the input pressure to the input chamber R23 is atmospheric pressure. ing. The set operation amount is set to exceed the maximum regenerative hydraulic braking start operation amount in FIG. Therefore, in the present cylinder device 570, when the brake pedal 150 is operated exceeding the set operation amount at the time of failure, the relief valve 572 is opened, and the operation force-based pressurization state is realized. Incidentally, since the relief valve is less expensive than the electromagnetic on-off valve, the cylinder device 570 is a relatively inexpensive cylinder device.

  Assuming that the annular chamber communication state is realized only by opening the relief valve 572, if the intermediate piston 406 is moved forward by operating force, the remaining pressure corresponding to the valve opening pressure of the relief valve 572 is left in the annular chamber R24. Since pressure exists, an operation in a state where an operation reaction force corresponding to the residual pressure is received is required. This causes a loss that the operating force is used for other than the pressurization by the first pressurizing piston 402 and the second pressurizing piston 404 at the time of failure. In view of that, in this cylinder device 570, when the intermediate piston 406 moves forward by a set amount, that is, when the volume of the annular chamber R24 becomes the set volume, that is, a mechanism for realizing the annular chamber communication state, A volume-based communication mechanism is provided.

  The volume-dependent communication mechanism will be specifically described as follows. When the seal member 530R passes through the housing side port due to the advance of the intermediate piston 406, the communication between the piston side port P1 and the housing side port P2 is cut off and the internal chamber non-communication state is realized. Is communicated with the communication passage 532 having the housing-side port P2, that is, the second communication passage through a gap formed between the intermediate piston 406 and the first housing member 410. In other words, when the intermediate piston 406 moves forward by a distance set by the positions of the housing side port P2 and the seal member 530R, and the volume of the annular chamber R24 becomes smaller than the set volume corresponding to the distance, the annular chamber R24. Is communicated with the reservoir 122. In the annular chamber communication state realized by the volume-based communication mechanism configured as described above, the annular chamber R24 is set to the atmospheric pressure, so that an operation reaction force due to the pressure of the annular chamber R24 is not generated, and operations in subsequent operations are performed. The force is used for pressurization by the first pressurizing piston 402 and the second pressurizing piston 404 with little loss.

  Under normal conditions, the pressure from the high pressure source device 118 is input to the input chamber R23 when the operation amount of the brake pedal 150 does not exceed the maximum regenerative hydraulic braking start operation amount. Therefore, even if the pressure in the annular chamber R24 becomes the set valve opening pressure, the relief valve 572 is not opened due to the increase in the input pressure. Therefore, the annular chamber R24 remains sealed, and the cylinder device 570 can operate in the same manner as the cylinder device 110 of the embodiment in the high pressure source pressure dependent pressurization state.

  In the cylinder device 570, when an operating force of a certain level or more is applied to the brake pedal 150, the annular chamber communication state is realized. Generally, a relief valve is cheaper than an electromagnetic on-off valve, and the cylinder device 570 is a relatively inexpensive cylinder device.

<< Modification 2 >>
FIG. 5 shows a hydraulic brake system 100 that employs a cylinder device 600 according to a modified example instead of the cylinder device 110 according to the embodiment. In the following description, only the configuration and operation different from the master cylinder device 110 of the embodiment will be described in consideration of simplification of the description, and the description of the same configuration and operation as the master cylinder device 110 of the embodiment will be omitted.

  In the cylinder device 600, a first housing member 602 is employed instead of the first housing member 410 of the cylinder device 110 of the embodiment. The first housing member 602 has the same structure as the first housing member 410 except for the communication path 532. More specifically, the first housing member 602 is provided with a communication hole 604 whose one end is a connection port and the other end is opened on the inner peripheral surface of the rear end portion of the front small-diameter portion 422 instead of the communication path 532. It has been. That is, the opening at the other end of the communication hole 604 is a housing-side port P2 like the opening of the communication path 532 of the cylinder device 110 of the embodiment. On the other hand, the connection port of the communication hole 604 is connected to the other end of the external communication path 606 whose one end is connected to the communication hole 522. That is, the communication hole 604 communicates with the reservoir 122 through the external communication path 606 and the like, and constitutes a second communication path that is connected to the reservoir 122 from the housing side port P2. Therefore, the internal chamber R26 can communicate with the reservoir 122 through the internal chamber communication path including the communication hole 528, the communication hole 604, the external communication path 606, and the like, which are the first communication paths. . Further, a mechanical on-off valve 610 capable of opening and closing the internal chamber communication path is provided in the middle of the external communication path 606.

  FIG. 6 is a sectional view of the on-off valve 610. The on-off valve 610 includes a housing 612 that is a housing, and a valve member 614 and a plunger 616 disposed inside the housing 612. The housing 612 has a cylindrical shape with both ends closed. A large inner diameter portion 618 having a large inner diameter and a small inner diameter portion 620 having a small inner diameter are formed inside the housing 612, and a step surface 622 is formed at the boundary between the inner diameter portions. In the housing 612, a partition member 624 having a generally cylindrical shape is fixedly fitted to the large inner diameter portion 618 in a state where the partition member 624 contacts the step surface 622. A communication hole 626 is provided at the center of the partition member 624. Further, the outer diameter of the outer periphery of the partition member 624 close to the step surface 622 is reduced, and a gap 628 is formed between the large inner diameter portion 618 of the housing 612 and the partition member 624.

  A liquid chamber R31 is partitioned by a partition member 624 in the large inner diameter portion 618 of the housing 612. A spherical valve element 614 and a compression coil spring 630 are arranged in the liquid chamber R31, and the valve element 614 is pressed against the communication hole 626 by the elastic reaction force of the spring 630. It has been. The diameter of the valve member 614 is larger than the diameter of the communication hole 626. That is, the partition member 624 functions as a valve seat, and the communication hole 626 can be blocked by the seat of the valve member 614. In this state, the on-off valve 610 is closed. A plunger 616 having a generally cylindrical shape is disposed in the small inner diameter portion 620 of the housing 612. One end of the plunger 616 is a tip portion 632 whose outer diameter is smaller than the diameter of the communication hole 626, and the other end is a base portion 634 whose outer diameter is slightly smaller than the inner diameter of the small inner diameter portion 620. . Therefore, the plunger 616 is fitted in the housing 612 in a state where the base portion 634 can slide on the small inner diameter portion 620. In addition, a liquid chamber R32 is defined in front of the plunger 616 by a small inner diameter portion 620, a partition member 624, and a plunger 616, and at the rear is a pilot pressure described later by the small inner diameter portion 620 and the plunger 616. A pilot pressure chamber R33 into which hydraulic fluid is introduced is defined. The pilot pressure chamber R33 is shown in a substantially collapsed state in FIG. Further, the liquid chamber R32 can communicate with the liquid chamber R31 through the communication hole 626 described above.

  A large-bore portion 618 of the housing 612 is provided with a communication hole 636 having one end opened to the liquid chamber R31 and the other end serving as a connection port. Further, a communication hole 638 having one end opened to the gap 628 and the other end serving as a connection port is provided near the step surface 622 of the large inner diameter portion 618. The partition member 624 is provided with a communication hole 640 that allows the gap 628 and the liquid chamber R32 to communicate with each other. Further, the small inner diameter portion 620 of the housing 612 is provided with a communication hole 642 having one end opened to the pilot pressure chamber R33 and the other end serving as a connection port.

  The connection ports of the communication holes 636 and 638 are connected to the external communication path 606, respectively. That is, the communication hole 636, the liquid chambers R31 and R32, the communication hole 640, the gap 628, and the communication hole 638 constitute a part of the external communication path 606. The connection port of the communication hole 642 is connected to a communication path branched from the external communication path 520, and the brake fluid having the same pressure as the brake fluid in the annular chamber R24 is supplied to the pilot pressure chamber R33. Therefore, the plunger 616 can operate such that its tip 632 passes through the communication hole 626 and presses the valve member 614 in accordance with the pressure of the hydraulic fluid in the annular chamber R24. When the force that presses the valve element 614 becomes equal to or greater than the force that presses the valve element 614 of the spring 630, the plunger 616 can separate the valve element 614 from the communication hole 626. In this state, the on-off valve 610 is opened.

  The operation of the cylinder device 600 including the internal chamber communication passage and the on-off valve 610 configured as described above will be described below. At the time of electrical failure, the on-off valve 524 is in the open state, so the pressure of the brake fluid in the annular chamber R24 and the external communication path 520 is atmospheric pressure. Therefore, in the on-off valve 610, the pressure of the brake fluid in the pilot pressure chamber R33 is atmospheric pressure. Therefore, the plunger 616 does not push the valve member 614. Further, the hydraulic fluid in the internal chamber R26 acts on the hydraulic fluid in the liquid chamber R32, but the on-off valve 610 is configured not to open by the pressure. More specifically, the area of the portion where the hydraulic fluid in the liquid chamber R32 acts on the valve element 614 is considerably reduced, and the force that pushes up the valve element 614 from the partition member 624 by the pressure of the hydraulic fluid is the spring. The on-off valve 610 is configured so that the force 630 does not increase the force that presses the valve member 614 against the partition member 624. Therefore, the open / close valve 610 is maintained in a closed state at the time of electrical failure. Therefore, the internal chamber R26 cannot communicate with the reservoir 122, and the internal chamber non-communication state is realized. That is, the cylinder device 600 can be considered to have a second communication state switching mechanism that includes the internal chamber communication passage and the on-off valve 610.

  As described above, in the cylinder device 600, when the electric failure occurs, the open / close valve is moved before the seal 530R passes through the housing-side port P2 by the advance of the intermediate piston 406, that is, in the state where the intermediate piston 406 is not advanced. By 610, the volume change of the internal chamber R26 is prohibited. As a result, the input piston 408 and the intermediate piston 406 are integrally moved forward with the start of the depression operation of the brake pedal 150 by the driver, and the driver pushes the first pressurizing piston 402 with his own force. be able to. Therefore, even when an electrical failure occurs, the brake device does not generate a braking force even when the brake operation is started, i.e., the brake operation has almost no state such as idling, and the driver feels uncomfortable. The brakes can be operated without any trouble.

  Further, when the seal 530R passes through the housing side port P2, since the communication between the piston side port P1 and the housing side port P2 is cut off, similarly to the cylinder device 110 of the embodiment, this also prevents the internal chamber from communicating. Is realized. As described above, the cylinder device 600 has the second communication state switching mechanism similar to the cylinder device 110 of the embodiment, together with the above-described second communication state switching mechanism including the internal chamber communication passage and the on-off valve 610. It can be considered that it also has a mechanism. As described above, the cylinder device 600 provided with the two types of second communication state switching mechanisms can be used as a backup device for the other, so that it is an excellent cylinder device in terms of fail-safe. ing.

  In the normal state, the on-off valve 524 is energized and closed so that the first communication state switching mechanism realizes an annular chamber non-communication state in which the annular chamber R24 and the reservoir 122 do not communicate with each other. . That is, the annular chamber R24 is sealed, and the forward movement of the intermediate piston 406 is prohibited. When the depression operation of the brake pedal 150 is started in this state, the input piston 408 starts moving forward, and the spring reaction forces of the first reaction force spring 480 and the second reaction force spring 482 are increased. Due to these spring reaction forces, a forward force is applied to the intermediate piston 406, and the brake fluid in the annular chamber R24 is pressurized by the flange 472 of the intermediate piston 406. Accordingly, since the pressure of the brake fluid in the pilot pressure chamber R33 also increases, the plunger 616 of the on-off valve 610 is moved to push up the valve member 614. That is, the on-off valve 610 is opened, and the internal chamber R26 communicates with the reservoir 122. Therefore, in the normal state, the internal chamber communication state is also realized by the second communication state switching mechanism including the on-off valve 610, and the forward movement of the input piston 408 relative to the intermediate piston 406 is allowed.

<< Modification 3 >>
FIG. 7 shows a hydraulic brake system 100 in which a cylinder device 700 according to a modification is employed instead of the cylinder device 110 according to the embodiment. The cylinder device 700 employs an electromagnetic on-off valve 702 in place of the mechanical on-off valve 610 in the cylinder device 600 of the second modification of the embodiment, and other configurations are the second modification of the embodiment. The cylinder device 600 has the same configuration. The on-off valve 702 is disposed in the external communication path 606 and is a normally closed valve that is in a non-excited and closed state so that it is normally opened and closed when an electrical failure occurs. . Therefore, in the event of an electrical failure, the internal chamber non-communication state is also realized by the second communication state switching mechanism including the on-off valve 702, and the input piston 408 and the intermediate piston 406 move forward together. Be made. Further, since the internal chamber non-communication state is realized regardless of the brake operation, the operation force-dependent pressurization state is realized when the depression operation of the brake pedal 150 is started.

  110: Cylinder device 116: Brake device 118: External high pressure source device 122: Reservoir 150: Brake pedal (operating member) 400: Housing 402: First pressurizing piston (pressurizing piston) 406: Intermediate piston 408: Input piston 470: Main body 472: collar 480: first reaction force spring (elastic force applying mechanism) 482: second reaction force spring (elastic force applying mechanism) 484: floating seat 520: external communication path 524: open / close valve 530F: seal member ( 530R: seal member (seal) R23: input chamber R24: annular chamber R26: internal chamber P1: piston side port P2: housing side port 570: cylinder device 572: relief valve 600: cylinder device 610: mechanical on-off valve Second communication state switching mechanism) 700: Cylinder 702: electromagnetic on-off valve (second communication state switching mechanism)

Claims (7)

A cylinder device that supplies pressurized brake fluid to the brake device in order to operate a brake device provided on the wheel,
A cylindrical housing with a closed front end;
A pressurizing piston disposed in the housing such that a pressurizing chamber for pressurizing the brake fluid is defined in front of the housing;
An input chamber into which pressure from a high-pressure source is input in front of the main body portion, and a front portion of the main body portion; An intermediate piston disposed in the housing such that an annular chamber whose volume changes with advancement and retraction is defined;
An input piston that is fitted to the rear end of the intermediate piston and is connected to the operation member at the rear end of the intermediate piston so that an inner chamber whose volume changes with relative movement with the intermediate piston is partitioned; ,
With the relative movement of the input piston and the intermediate piston in the direction in which the volume of the internal chamber decreases, the elastic force is applied to the input piston and the intermediate piston in the direction opposite to the relative movement. Mechanism,
A first communication state switching mechanism that selectively realizes an annular chamber communication state in which the annular chamber and the reservoir communicate with each other and an annular chamber non-communication state in which the annular chamber does not communicate with each other;
A second communication state switching mechanism that selectively realizes an internal chamber communication state in which the internal chamber and the reservoir communicate with each other and an internal chamber non-communication state in which the internal chamber does not communicate with each other;
In the annular chamber non-communication state and the internal chamber communication state, the forward movement of the intermediate piston is prohibited while allowing relative movement between the input piston and the intermediate piston accompanied by a change in volume of the internal chamber. An operation reaction force corresponding to the operation amount of the operation member is generated based on the elastic force of the elastic force applying mechanism, and the pressurization chamber brake according to the pressure from the high pressure source input to the input chamber Allows pressurization of the liquid,
In the annular chamber communication state and the internal chamber non-communication state, the volume change of the internal chamber is prohibited, and the relative movement between the input piston and the intermediate piston is prohibited, while the pressure piston is in contact A cylinder device configured to allow pressurization of the brake fluid in the pressurizing chamber by an operation force applied to the operation member by allowing the intermediate piston to advance. The second communication state switching mechanism is
The internal chamber communication path for communicating the internal chamber and the reservoir, and an open / close valve provided in the internal chamber communication path for opening and closing the communication path. Cylinder device. The intermediate piston is
Through two seals fitted to the outer peripheral surface of the main body portion of the intermediate piston at positions separated from each other in the front-rear direction, and in sliding contact with the inner peripheral surface of the housing; and the inner chamber; A first communication path that connects a piston-side port formed on the outer peripheral surface of the body portion of the intermediate piston at a position between the two seals;
The housing comprises:
A second communication path connected to the reservoir from a housing-side port formed on the inner peripheral surface of the housing at a position facing the portion between the two seals of the intermediate piston when the intermediate piston is not advanced. Have
The internal chamber communication path is configured including the first communication path and the second communication path, and the open / close valve is configured including the two seals, the piston side port, and the housing side port,
The second communication state switching mechanism is
The piston-side port and the housing-side port communicate with each other when the intermediate piston is not moving forward, thereby realizing the internal chamber communication state. The inner chamber non-communication state is realized by facing the outer peripheral surface of the intermediate piston at a position on the rear side of the two seals and not connecting the piston side port and the housing side port. The cylinder device according to claim 1 constituted.   The first communication state switching mechanism includes an annular chamber communication passage for communicating the annular chamber and the reservoir, and an opening / closing valve provided in the annular chamber communication passage for opening and closing the communication passage. The cylinder device according to any one of claims 1 to 3, wherein the cylinder device is configured.   When the first communication state switching mechanism is provided in the annular chamber communication passage for communicating the annular chamber and the reservoir, and the annular chamber communication passage is provided with a pressure in the annular chamber exceeding a set pressure. The cylinder device according to any one of claims 1 to 3, comprising a relief valve that opens and closes the communication passage. The cylinder device is
A spring disposed in the internal chamber and acting on the input piston and the intermediate piston in a direction in which the volume of the internal chamber increases in its own elastic force;
The cylinder device according to any one of claims 1 to 5, wherein the elastic force applying mechanism includes the spring. The cylinder device is
Each functions as the spring, with one end supported by one of the input piston and the intermediate piston and the other end supported by the other of the input piston and the intermediate piston. Two springs arranged in series in the inner chamber and having different spring constants;
The two springs are sandwiched between one other end and the other other end, and are floatingly supported by the two springs, and the volume of the inner chamber is increased by the elastic force of the two springs. A floating seat connecting the two springs to act on the input piston and the intermediate piston in the direction of
The elastic force applying mechanism is configured including the two springs and the floating seat,
When the input piston and the intermediate piston move relative to each other so that the relative movement amount exceeds a set amount, the input piston and the intermediate piston are prohibited from approaching the floating seat. The cylinder device according to claim 6, which is configured so that the amount of elastic deformation of one of the two springs does not increase.

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