JP2004359215A - Master cylinder with built-in stroke simulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a master cylinder with a built-in stroke simulator which is capable of adequately monitoring a communicated state of a seal member, reliable as a communication blocking means, and capable of further shortening the total length thereof. <P>SOLUTION: A first communication passage P1 is formed in a master piston MP so that a master hydraulic pressure chamber C1 is communicated with an atmospheric pressure chamber C3 when the master piston MP is at the initial position, and communication of the master hydraulic pressure chamber with the atmospheric pressure chamber is shut off by a seal member S1 when the master piston is moved forward from the initial position by at least the first stroke. A second communication passage P2 is formed so that a simulator chamber C2 is communicated with the atmospheric pressure chamber when the master piston is at the initial position, and communication of the simulator chamber with the atmospheric pressure chamber is shut off by the seal member when the master piston is moved forward from the initial position by at least the second stroke larger than the first stroke. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a master cylinder provided for a hydraulic brake device of a vehicle, and more particularly to a master cylinder having a built-in stroke simulator.

  Various types of hydraulic brake devices having a stroke simulator are known, but a hydraulic pressure control unit including a hydraulic pressure source controls the hydraulic pressure source according to the operation of the brake operating member in a normal state. The hydraulic pressure is adjusted and supplied to the wheel cylinder, and the communication between the master cylinder and the wheel cylinder is cut off. When the hydraulic pressure control means is abnormal, the master cylinder and the wheel cylinder are communicated with each other. Therefore, there is a type configured to supply a hydraulic pressure corresponding to the operating force of a brake operating member to a wheel cylinder, and is disclosed in, for example, Patent Document 1 below.

  In the above-described hydraulic brake device, the stroke simulator is configured such that when the hydraulic pressure control means is normal, that is, when the communication between the master cylinder and the wheel cylinder is interrupted, the stroke corresponding to the brake operating force is applied to the brake operating member. Is configured to occur. In the hydraulic brake device described in Patent Literature 1, the stroke simulator is interposed between the brake operating member and the master piston, and when the hydraulic pressure control means is abnormal, that is, when the master cylinder moves from the master cylinder to the wheel cylinder. When the hydraulic pressure is supplied, the communication between the simulator chamber and the atmospheric pressure chamber is cut off according to the movement of the master piston, in view of the fact that the brake pedal needs to be largely stroked according to the stroke of the stroke simulator. A seal member is additionally provided as a communication blocking means to suppress the stroke of the stroke simulator when hydraulic pressure is supplied from the master cylinder to the wheel cylinder.

JP-A-11-59349

  However, in the hydraulic brake device described in Patent Document 1, even if a state in which the seal member as the communication blocking means does not function sufficiently occurs, the state is confirmed when the hydraulic pressure control means is normal. It is not possible to do so, and it is necessary to make a large stroke of the brake operating member when the hydraulic pressure control means is abnormal. Therefore, there is room for further improvement in the reliability of the seal member as the communication blocking means. Further, in the device described in Patent Document 1, since the stroke simulator is arranged behind the master piston, the overall length of the master cylinder is long, and it cannot be said that the device sufficiently responds to the demand for miniaturization.

  Therefore, the present invention appropriately monitors the communication state of a seal member as a communication blocking means in a master cylinder incorporating a stroke simulator used as a component of a hydraulic brake device of a vehicle, and improves reliability as the communication blocking means. It is an object of the present invention to provide a master cylinder with a built-in stroke simulator, which has a high performance and can further reduce the overall length of the master cylinder.

  In order to achieve the above object, according to the present invention, as described in claim 1, a cylinder housing having an atmospheric pressure chamber in which an atmospheric pressure brake fluid is stored is slidably housed in the cylinder housing. A simulator piston that forms a master hydraulic chamber in front of the vehicle, a simulator chamber that forms a simulator chamber in front thereof, and a simulator piston that moves back and forth in conjunction with a brake operating member; and an operating force of the brake operating member with respect to the simulator piston. A stroke simulator that transmits an operating force of the brake operating member to the master piston via the elastic member and the simulator piston; and And slidably support in a liquid-tight manner. A master cylinder with a built-in stroke simulator having a seal member disposed in the cylinder housing such that the hydraulic pressure of the atmospheric pressure chamber acts on the simulator chamber when the master piston is at an initial position. When the master piston moves forward from the initial position by a predetermined stroke or more from the initial position, the master piston communicates with the master piston so that communication between the simulator chamber and the atmospheric pressure chamber is interrupted by the seal member. Is formed.

  Thus, when the communication between the master cylinder and the wheel cylinder is interrupted, a stroke corresponding to the brake operating force is generated on the brake operating member, and when the hydraulic pressure is supplied from the master cylinder to the wheel cylinder, the brake is released. The braking force can be appropriately secured without increasing the stroke of the operation member.

  The simulator piston may be configured to be slidably housed in the master piston. Further, as described in claim 3, an annular chamber communicating with the master hydraulic chamber and formed on the outer periphery of the master piston in front of the seal member may be provided.

  Further, as set forth in claim 4, the master hydraulic chamber is slidably accommodated in a cylinder housing having an atmospheric pressure chamber for accommodating brake fluid at atmospheric pressure, and a master hydraulic chamber is formed in the front of the cylinder housing. With a master piston, a simulator chamber is formed in the front, a simulator piston that moves back and forth in conjunction with a brake operation member, and an elastic member that applies a stroke to the simulator piston according to the operation force of the brake operation member. A stroke simulator for transmitting the operating force of the brake operating member to the master piston via the elastic member and the simulator piston, and supporting the master piston slidably in the cylinder housing in a liquid-tight manner. , The hydraulic pressure of the master hydraulic chamber acts on the front, and the hydraulic pressure of the atmospheric pressure chamber acts on the rear. The master hydraulic chamber is communicated with the atmospheric pressure chamber when the master piston is at the initial position in the master cylinder with the built-in stroke simulator having a seal member disposed in the cylinder housing. A first communication passage is formed in the master piston so that the communication between the master hydraulic chamber and the atmospheric pressure chamber is blocked by the seal member when the cylinder moves forward from the initial position by a first stroke or more. When the master piston is at the initial position, the simulator chamber communicates with the atmospheric pressure chamber. When the master piston moves forward from the initial position by at least a second stroke larger than the first stroke, the simulator So that the communication between the chamber and the atmospheric pressure chamber is interrupted by the seal member. The second communicating path may be formed on the master piston.

  In the master cylinder according to the fourth aspect, as in the fifth aspect, the simulator piston may be configured to be slidably housed in the master piston.

  The present invention has the following effects because it is configured as described above. That is, according to the master cylinder with a built-in stroke simulator according to the first aspect, when the master piston is at the initial position, the simulator chamber is communicated with the atmospheric pressure chamber through the communication passage, and the master piston is moved from the initial position by a predetermined stroke or more. When moving forward, communication between the simulator chamber and the atmospheric pressure chamber via the communication path is blocked by the seal member. Therefore, in the event of an abnormal supply of hydraulic pressure from the master cylinder to the wheel cylinder, the communication between the simulator chamber and the atmospheric pressure chamber is interrupted by the seal member, so that the desired braking force can be obtained without increasing the stroke of the brake operating member. Can be secured. In addition, even when the hydraulic pressure is controlled in a state where the communication between the master cylinder and the wheel cylinder is interrupted, the driver can recognize the abnormality of the seal member based on the moving state of the master piston. The properties are further improved.

  Furthermore, if the simulator piston is slidably housed in the master piston as described in claim 2, the overall length of the master cylinder can be shortened, so that the size can be further reduced. And it can also be comprised like Claim 3, and the degree of freedom of design increases.

  Also, in the master cylinder according to the fourth aspect, when the hydraulic pressure is supplied from the master cylinder to the wheel cylinder, the communication between the simulator chamber and the atmospheric pressure chamber is interrupted by the seal member. A desired braking force can be secured without increasing the stroke. In addition, even when the hydraulic pressure is controlled in a state where the communication between the master cylinder and the wheel cylinder is interrupted, the driver can recognize the abnormality of the seal member based on the moving state of the master piston. The properties are further improved.

  Further, if the simulator piston is slidably housed in the master piston as described in claim 5, the overall length of the master cylinder can be shortened, so that the size can be further reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a vehicle hydraulic brake device provided with a master cylinder with a built-in stroke simulator according to an embodiment of the present invention. The hydraulic brake device is operated in response to an operation of a brake pedal BP (a brake operation by a driver). A master cylinder MC for generating pressure and a wheel cylinder (represented by WC) for applying a braking force to each wheel of the vehicle by the output hydraulic pressure are provided. A normally open solenoid valve NO is interposed between the master cylinder MC and the wheel cylinder WC. Further, a hydraulic pressure source PG that generates and outputs a predetermined hydraulic pressure irrespective of a driver's brake operation is connected to a hydraulic pressure path between the electromagnetic on-off valve NO and the wheel cylinder WC.

  The hydraulic pressure source PG includes an electric motor M controlled by an electronic control unit ECU, and a hydraulic pump HP driven by the electric motor M. The input side of the hydraulic pressure source PG has an atmospheric pressure reservoir RS (hereinafter simply referred to as a reservoir RS). And the output side is connected to the accumulator AC. In the present embodiment, the pressure sensor Sps is connected to the output side, and the detected pressure of the pressure sensor Sps is monitored by the electronic control unit ECU. Based on the monitoring result, the electric motor M is controlled by the electronic control unit ECU such that the hydraulic pressure of the accumulator AC is maintained at a pressure between a predetermined upper limit and a lower limit. An accumulator AC is connected to a hydraulic path between the electromagnetic on-off valve NO and the wheel cylinder WC via a normally closed first proportional electromagnetic valve SV1, and the output hydraulic pressure of the hydraulic pressure source PG is adjusted. The pressure is supplied to the wheel cylinder WC, and a reservoir RS is connected via a normally closed second proportional solenoid valve SV2, so that the hydraulic pressure of the wheel cylinder WC is reduced and adjusted. ing. The hydraulic pressure control means PC is constituted by the hydraulic pressure source PG, the first and second proportional solenoid valves SV1 and SV2, the electronic control unit ECU, and the following sensors.

  In the present embodiment, a pressure sensor Smc is connected to a hydraulic path between the master cylinder MC and the electromagnetic on-off valve NO, and a pressure sensor Swc is connected to a hydraulic path between the electromagnetic on-off valve NO and the wheel cylinder WC. Is connected. Further, a stroke sensor BS for detecting a stroke of the brake pedal BP is arranged, and these detection signals are input to the electronic control unit ECU. These sensors monitor the output hydraulic pressure of the master cylinder MC, the brake hydraulic pressure of the wheel cylinder WC, and the stroke of the brake pedal BP. Further, a sensor (typically represented by SN) such as a wheel speed sensor and an acceleration sensor for various controls such as anti-lock control is provided, and these detection signals are also inputted to the electronic control unit ECU. Have been.

  In the master cylinder MC of the present embodiment, as shown in an enlarged manner in FIG. 2, a master piston MP is slidably accommodated in a cylinder housing HS, and a master hydraulic chamber C1 is formed in front of the master piston MP. It is configured to communicate with the wheel cylinder WC via the electromagnetic on-off valve NO. A return spring (compression spring) R1 is housed in the master hydraulic chamber C1, and the master piston MP is urged rearward by this urging force. A simulator piston SP is slidably accommodated in a cylinder housing HS behind the master piston MP, and a simulator room C2 is formed in front of the piston.

  The simulator piston SP is configured to move back and forth in conjunction with a brake pedal BP serving as a brake operation member, and to be given a stroke corresponding to an operation force of the brake pedal BP by a compression spring R2 serving as an elastic member. Thus, a stroke simulator SM is configured, and the operating force of the brake pedal BP is transmitted to the master piston MP via the compression spring R2 and the simulator piston SP. The compression spring R2 of the present embodiment is provided between a rod RD fixed to the master piston MP and a retainer RT having a front end slidably engaged with the rod RD and a rear end abutting on the simulator piston SP. They are stretched, and these define the maximum distance between the master piston MP and the simulator piston SP.

  As shown in FIG. 2, in the cylinder housing HS, a master piston MP is slidably supported in a liquid-tight manner via a seal member S1 and a seal member S2 having a shutoff function, and a simulator piston MP is provided via a seal member S3. The SP is slidably supported in a liquid-tight manner. In the present embodiment, seal members S1 and S2 are respectively held in a pair of annular grooves formed to be juxtaposed on the inner peripheral surface of the cylinder housing HS, and seal members S1 and S2 are held in the annular grooves formed on the outer peripheral surface of the simulator piston SP. The member S3 is held. An atmospheric pressure chamber C3 is formed between the seal member S1 and the seal member S2 between the inner peripheral surface of the cylinder housing HS and the outer peripheral surface of the master piston MP, and is connected to the reservoir RS. Although the cylinder housing HS is shown as a single body in FIGS. 1 and 2 for ease of explanation, it is actually configured by combining a plurality of cylinder members.

  As shown in FIG. 2, a first communication path P1 is formed in the master piston MP. When the master piston MP is at the initial position, the master hydraulic chamber C1 is connected to the atmospheric pressure via the first communication path P1. When the master piston MP moves forward from the initial position by the first stroke (d1) or more from the initial position, the opening of the first communication passage P1 is shielded by the seal member S1, and the master piston MP is in communication with the master hydraulic chamber C1. The communication with the pressure chamber C3 is shut off.

  Further, a second communication path P2 is formed in the master piston MP as shown in FIG. 2. When the master piston MP is at the initial position, the simulator chamber C2 is communicated with the atmospheric pressure chamber C3, and the master piston MP Has moved forward from the initial position by a second stroke (d2) greater than the first stroke (d1), the opening of the second communication path P2 is blocked by the seal member S1, and the opening of the second communication path P2 is largely separated from the simulator chamber C2. The communication with the pressure chamber C3 is shut off.

  Regarding the hydraulic brake device including the master cylinder MC configured as described above, first, the operation when the hydraulic pressure control means PC is normal will be described. When the brake pedal BP is operated, the stroke is detected by the stroke sensor BS, and the output hydraulic pressure of the master cylinder MC is detected by the pressure sensor Smc. When these are detected, the electronic control unit ECU excites the electromagnetic on-off valve NO to bring it to the closed position, and the communication between the master hydraulic chamber C1 and the wheel cylinder WC is cut off. Further, in the electronic control unit ECU, a target wheel cylinder hydraulic pressure is calculated according to the detected stroke of the brake pedal BP and the output hydraulic pressure of the master cylinder MC, and the target wheel cylinder hydraulic pressure detected by the pressure sensor Swc is calculated. Output currents to the first proportional solenoid valve SV1 and the second proportional solenoid valve SV2 are appropriately controlled so that the wheel cylinder hydraulic pressure is obtained. Thus, the hydraulic pressure according to the operation of the brake pedal BP is supplied to the wheel cylinder WC by the hydraulic pressure control means PC.

  When the hydraulic pressure control means PC is normal as described above, the master cylinder MC operates as follows. When the brake pedal BP is operated, the brake operation force is transmitted to the master piston MP via the simulator piston SP and the elastic member (compression spring R2), and the master piston MP moves forward against the urging force of the return spring R1. . When the master piston MP moves forward from the initial position by the first stroke (d1), the open end of the first communication passage P1 is shielded by the seal member S1, and communication between the master hydraulic chamber C1 and the atmospheric pressure chamber C3 is established. Will be shut off. Therefore, when the brake pedal BP is further operated, a hydraulic pressure corresponding to the brake operating force is generated in the master hydraulic pressure chamber C1.

  At this time, the solenoid on-off valve NO is excited (ON) to be in the closed position, and the communication between the master hydraulic chamber C1 and the wheel cylinder WC is cut off, so that the master hydraulic chamber C1 becomes a closed chamber, Thereafter, even if further operating force is applied to the brake pedal BP, the master piston MP hardly moves forward. In this state, the movement of the master piston MP is smaller than the second stroke (d2), and the simulator chamber C2 communicates with the atmospheric pressure chamber C3. Therefore, when the brake operation force applied to the simulator piston SP is equal to or larger than the mounting load of the compression spring R2 of the stroke simulator SM, the compression spring R2 is compressed, and a stroke corresponding to the brake operation force is generated on the simulator piston SP. I do. As a result, a stroke corresponding to the brake operation force is generated on the brake pedal BP.

  On the other hand, when an abnormality occurs in the hydraulic pressure control means PC such as the hydraulic pressure source PG, the solenoid on-off valve NO is de-energized (OFF) to be opened and the master hydraulic chamber C1 communicates with the wheel cylinder WC. State. In addition, the first proportional solenoid valve SV1 and the second proportional solenoid valve SV2 are also de-energized (OFF) to be in the closed position, and the hydraulic pressure source PG does not supply the hydraulic pressure to the wheel cylinder WC. When the brake pedal BP is operated in this state, a hydraulic pressure corresponding to the brake operation force is supplied from the master cylinder MC to the wheel cylinder WC. As a result, even when an abnormality occurs in the hydraulic pressure control means PC, the braking force is ensured.

  When an abnormality occurs in the hydraulic pressure control means PC, the master cylinder MC operates as follows. When the brake pedal BP is operated and the master piston MP moves forward from the initial position by the first stroke (d1), the master hydraulic pressure chamber C1 and the atmospheric pressure chamber C3 are operated as in the case where the hydraulic pressure control means PC is normal. Communication with is interrupted. However, when the hydraulic pressure control means PC is abnormal, since the master hydraulic pressure chamber C1 and the wheel cylinder WC are in communication with each other via the electromagnetic opening / closing valve NO at the open position, the brake pedal BP is further operated. Then, the hydraulic pressure in the master hydraulic chamber C1 is supplied to the wheel cylinder WC, and the master piston MP further moves forward and moves forward from the initial position by a second stroke (d2). Is shielded by the seal member S1, and the communication between the simulator chamber C2 and the atmospheric pressure chamber C3 is cut off. When the master piston MP moves forward by further operating the brake pedal BP, the simulator chamber C2 communicates with the master hydraulic chamber C1 via the second communication path P2.

  Thus, the communication between the simulator chamber C2 and the atmospheric pressure chamber C3 is interrupted, and the simulator chamber C2 and the master hydraulic chamber C1 are in communication with each other. In this state, the compression spring R2 is not compressed until the compression load of the return spring R1 of the master piston MP exceeds the mounting load of the compression spring R2 of the stroke simulator SM, so that the stroke of the stroke simulator SM does not stroke. Further, even if the master piston MP is driven forward and the compression load of the return spring R1 exceeds the mounting load of the compression spring R2 of the stroke simulator SM and the compression spring R2 is compressed, the output hydraulic pressure of the simulator chamber C2 is reduced. Is supplied to the wheel cylinder WC via the master hydraulic chamber C1, and the stroke in the stroke simulator SM at this time does not become a so-called invalid stroke. Therefore, even when an abnormality occurs in the hydraulic pressure control means PC, the braking force can be appropriately secured without increasing the stroke of the brake pedal BP.

  In the present embodiment, if an abnormality occurs in the shutoff function of the seal member S1, the driver can recognize the abnormality when the hydraulic pressure control means PC is normal. That is, if an abnormality occurs in the shutoff function of the seal member S1 while the hydraulic pressure control means PC is normal, the brake pedal BP is operated and the master piston MP moves forward from the initial position by the first stroke (d1) or more. However, since the communication between the master hydraulic chamber C1 and the atmospheric pressure chamber C3 is not interrupted, even when the communication between the master hydraulic chamber C1 and the wheel cylinder WC is interrupted when the solenoid on-off valve NO is in the closed position, the master is not disconnected. The hydraulic chamber C1 does not become a closed chamber, and the master piston MP moves forward in response to the operation of the brake pedal BP. Furthermore, even if the master piston MP moves forward from the initial position by the second stroke (d2) or more, the communication between the simulator chamber C2 and the atmospheric pressure chamber C3 is not interrupted, so that the stroke simulator SM also makes a stroke.

As a result, for the brake pedal BP, a large stroke is generated with respect to the brake operating force (same level) as compared with the case where the shut-off function of the seal member S1 is normal, and the driver has an abnormality Can be recognized, and repairs and the like can be appropriately performed. At this time, since the hydraulic pressure control means PC is normal, the hydraulic pressure according to the stroke of the brake pedal BP detected by the stroke sensor BS is supplied from the hydraulic pressure control means PC to the wheel cylinder WC. Power can be secured.

  FIG. 3 shows another embodiment of the present invention, in which components substantially the same as those of the master cylinder MC in FIG. 2 are denoted by the same reference numerals. In the master cylinder MC2 of this embodiment, unlike the master piston MP and the simulator piston SP of FIG. 2, the master piston MP2 is slidably housed in the cylinder housing HS2, and the simulator piston SP2 slides in the master piston MP2. It is configured to be freely accommodated. Therefore, the overall length is greatly reduced as compared with the embodiment of FIG. 2, and further downsizing is possible. However, the effective pressure receiving area of the simulator piston SP2 (effective diameter) is smaller than the effective pressure receiving area of the master piston MP2 (or the effective diameter contributing to the effective pressure receiving area). Note that the rod RD and the retainer RT are not provided.

  Also in the present embodiment, when the hydraulic pressure control means PC is normal, it operates similarly to the master cylinder MC in FIG. On the other hand, when an abnormality occurs in the hydraulic pressure control means PC, the master piston MP2 moves forward from the initial position by the second stroke (d2) or more, and the communication between the simulator chamber C2 and the atmospheric pressure chamber C3 is cut off. When the simulator chamber C2 and the master hydraulic chamber C1 are in communication with each other, the hydraulic pressure of the master hydraulic chamber C1 is integrated with the difference between the effective receiving area of the master piston MP2 and the effective receiving area of the simulator piston SP2. The compression spring R2 is compressed such that the compression load of the compression spring R2 of the stroke simulator SM2 is equal to the force obtained by adding the compression load of the return spring R1 of the master piston MP2 to the applied force, and the stroke simulator SM2 performs a stroke. . Also in this case, the hydraulic pressure in the simulator chamber C2 is supplied to the wheel cylinder WC via the master hydraulic chamber C1, so that the stroke in the stroke simulator SM2 at this time does not become an invalid stroke. Therefore, even when an abnormality occurs in the hydraulic pressure control means PC, the braking force can be appropriately secured without increasing the stroke of the brake pedal BP.

  Also, in the present embodiment, if an abnormality occurs in the shutoff function of the seal member S1, similarly to the above-described embodiment, when the control means PC is normal, the brake operating force (of the same order) is obtained. On the other hand, since a larger stroke is generated as compared with the case where the blocking function of the seal member S1 is normal, the driver can recognize the abnormality while securing a desired braking force.

  FIG. 4 shows still another embodiment of the present invention, in which components substantially the same as those of the master cylinder MC2 in FIG. 3 are denoted by the same reference numerals. In the present embodiment, similarly to FIG. 3, the simulator piston SP2 is configured to be slidably housed in the master piston MP3, and the master piston MP3 is also formed with the second communication path P2. , The first communication path P1 is not formed. Instead, a communication passage P3 and a recess P4 that can communicate the master hydraulic chamber C1 with the reservoir RS are formed in the cylinder housing HS3. Further, retainers RT1 and RT2 are provided in the master hydraulic chamber C1, and a return spring R1 is stretched between them. Further, the proximal end of the rod RD2 is locked to the rear retainer RT2, and a compression spring R3 is stretched between the distal end of the rod RD2 and the front retainer RT1. A cylindrical seal member S0 is fitted in the concave portion P4, and a first stroke (d1) is secured between the seal member S0 and the tip of the rod RD2.

  In this embodiment, when the hydraulic pressure control means PC is normal, the master cylinder MC3 operates as follows. When the brake pedal BP is operated, the brake operation force is transmitted to the master piston MP3 via the simulator piston SP2 and the elastic member (compression spring R2), and the master piston MP3 moves forward against the urging force of the return spring R1. . When the master piston MP3 moves forward from the initial position by the first stroke (d1), the open end of the communication path P3 is blocked by the tip of the rod RD2, and the communication between the master hydraulic chamber C1 and the reservoir RS is cut off. . Therefore, when the brake pedal BP is further operated, a hydraulic pressure corresponding to the brake operating force is generated in the master hydraulic pressure chamber C1.

  On the other hand, for example, when an abnormality occurs in the hydraulic pressure control means PC, the master piston MP2 moves forward from the initial position by the second stroke (d2) or more, and communication between the simulator chamber C2 and the atmospheric pressure chamber C3 is established. When the simulator chamber C2 and the master hydraulic chamber C1 are in communication with each other, the hydraulic pressure of the master hydraulic chamber C1 is reduced to the difference between the effective cross-sectional area of the master piston MP3 and the effective cross-sectional area of the simulator piston SP2. The compression spring R2 is compressed so that the force obtained by adding the compression load of the return spring R1 of the master piston MP3 to the integrated force is equal to the compression load of the compression spring R2 of the stroke simulator SM2. I do. Also in this case, the hydraulic pressure in the simulator chamber C2 is supplied to the wheel cylinder WC via the master hydraulic chamber C1, so that the stroke in the stroke simulator SM2 at this time does not become an invalid stroke. Therefore, even when an abnormality occurs in the hydraulic pressure control means PC, the braking force can be appropriately secured without increasing the stroke of the brake pedal BP.

  Further, if an abnormality occurs in the shutoff function of the seal member S1, similarly to the above-described embodiment, when the control means PC is normal, the seal member S1 is subjected to (same level of) brake operation force. Since a larger stroke occurs as compared with the case where the function is normal, the driver can recognize the abnormality while securing a desired braking force.

  FIG. 5 shows another embodiment of the present invention, in which components substantially the same as those of the master cylinder MC2 in FIG. 3 are denoted by the same reference numerals. The master cylinder MC4 of this embodiment is configured such that the simulator piston SP2 is slidably housed in the master piston MP4, as in FIG. 3, and also has a second communication path P2. The first communication path P1 is not formed. As in the embodiment of FIG. 4, a communication passage P3 that allows the master hydraulic chamber C1 to communicate with the reservoir RS is formed in the cylinder housing HS4, and a normally-open electromagnetic wave is provided between the communication passage P3 and the reservoir RS. An on-off valve NO2 is interposed. The electromagnetic on-off valve NO2 is configured to be always in the open position and to be in the closed position in accordance with the stroke of the brake pedal BP. Therefore, the seal member S1 and the first communication passage P1 as shown in FIG. Does not need to set the first stroke (d1). Therefore, the stroke adjustment in the present embodiment is only the predetermined stroke ds set to the same distance as the second stroke (d2) in each of the above-described embodiments. The operation of this embodiment is the same as that of the embodiment of FIG.

  FIG. 6 shows still another embodiment of the present invention, in which components substantially the same as those of the master cylinder MC in FIG. 2 are denoted by the same reference numerals. The simulator SM of the present embodiment has the same configuration as that of FIG. 2, and the master piston MP5 has the same configuration as the master piston MP of FIG. 2. However, the first communication passage P1 and the second communication passage An annular chamber C5 is formed between the master piston MP5 and P2, and the master piston MP5 is elongated, and thus the cylinder housing HS5 is elongated. Further, seal members S4 and S5 are added, and an atmospheric pressure chamber C4 is formed between the seal members S4 and S5 so that the atmospheric pressure chamber C4 can communicate with the master hydraulic chamber C1 via the first communication path P1. In the master piston MP5, a communication passage P5 communicating with the master hydraulic chamber C1 is formed so as to open between the seal members S1 and S5, and the annular chamber C5 is always connected to the master hydraulic chamber C1. Communicating. Note that the operation of this embodiment is substantially the same as that of the embodiment of FIG.

  In any of the above embodiments, the master cylinder MC or the like applies the mounting load of the elastic member (compression spring R2) such as the stroke simulator SM to the second stroke (d2) from the initial position by the master piston MP (or FIG. 5). The stroke (ds) is set to be larger than the load of the return spring R1 when moving forward, but may be set smaller. In this case, when the hydraulic pressure control means PC is abnormal, the stroke of the stroke simulator SM or the like occurs before the master piston MP or the like moves forward from the initial position by the stroke (d2 or ds). However, since the stroke of the stroke simulator SM or the like is suppressed after the master piston MP or the like has moved forward from the initial position by the stroke (d2 or ds), it is possible to prevent the stroke of the brake pedal BP from increasing.

  If necessary, an orifice (not shown) for restricting the outflow of the brake fluid from the simulator chamber C2 to the atmospheric pressure chamber C3 when the brake pedal BP is suddenly operated may be provided in the second communication passage P2. The operation feeling of the brake pedal BP can be adjusted. In addition, a floating piston (not shown) may be arranged in the master hydraulic chamber C1 to form a tandem master cylinder having two master hydraulic chambers. Further, by comparing the stroke of the brake pedal BP detected by the stroke sensor BS with the hydraulic pressure of the master hydraulic chamber C1 detected by the pressure sensor Smc, it is detected that an abnormality has occurred in the shut-off function of the seal member S1. The warning may be issued in accordance with the detection result to notify the driver.

1 is a configuration diagram illustrating an outline of a vehicle hydraulic brake device including a master cylinder with a built-in stroke simulator according to an embodiment of the present invention. 1 is a sectional view of a master cylinder with a built-in stroke simulator according to an embodiment of the present invention. It is sectional drawing of the master cylinder with a built-in stroke simulator which concerns on other embodiment of this invention. It is sectional drawing of the master cylinder with a built-in stroke simulator which concerns on yet another embodiment of this invention. It is sectional drawing of the master cylinder with a built-in stroke simulator which concerns on another embodiment of this invention. It is sectional drawing of the master cylinder with a built-in stroke simulator which concerns on another embodiment of this invention.

Explanation of reference numerals

MC Master cylinder PG Hydraulic pressure source RS Reservoir HS, HS2, HS3, HS4, HS5 Cylinder housing BP Brake pedal MP, MP2, MP3, MP4, MP5 Master piston SP, SP2 Simulator piston C1 Master hydraulic chamber C2 Simulator room C3, C4 Atmospheric pressure chamber C5 Annular chamber NO, NO2 Solenoid on-off valve SV1 First proportional solenoid valve SV2 Second proportional solenoid valve

Claims (5)

  A master piston that forms a master hydraulic chamber is provided slidably in a cylinder housing having an atmospheric pressure chamber in which an atmospheric pressure brake fluid is stored, and a simulator chamber is provided in the front in the cylinder housing. A simulator piston that is formed and moves back and forth in conjunction with a brake operating member; and an elastic member that applies a stroke to the simulator piston in accordance with the operating force of the brake operating member. A stroke simulator for transmitting the operating force of the brake operating member to the master piston via the master piston, and the master piston slidably supported in the cylinder housing in a liquid-tight manner, and the hydraulic pressure of the master hydraulic chamber is set forward. Acts so that the hydraulic pressure of the atmospheric pressure chamber acts rearward. In the master cylinder with a built-in stroke simulator having a seal member disposed therein, when the master piston is at the initial position, the simulator chamber communicates with the atmospheric pressure chamber, and the master piston is at least a predetermined stroke from the initial position. A master cylinder with a built-in stroke simulator, wherein a communication passage is formed in the master piston so that communication between the simulator chamber and the atmospheric pressure chamber is blocked by the seal member when the master piston moves forward.   The master cylinder with a built-in stroke simulator according to claim 1, wherein the simulator piston is slidably housed in the master piston.   The master cylinder with a built-in stroke simulator according to claim 1, further comprising an annular chamber communicating with the master hydraulic chamber and formed on an outer periphery of the master piston in front of the seal member.   A master piston that forms a master hydraulic chamber is provided slidably in a cylinder housing having an atmospheric pressure chamber in which an atmospheric pressure brake fluid is stored, and a simulator chamber is provided in the front in the cylinder housing. A simulator piston that is formed and moves back and forth in conjunction with a brake operating member; and an elastic member that applies a stroke to the simulator piston in accordance with the operating force of the brake operating member. A stroke simulator for transmitting the operating force of the brake operating member to the master piston via the master piston, and the master piston slidably supported in the cylinder housing in a liquid-tight manner, and the hydraulic pressure of the master hydraulic chamber is set forward. Acts so that the hydraulic pressure of the atmospheric pressure chamber acts rearward. In the master cylinder with a built-in stroke simulator having a seal member disposed therein, when the master piston is at the initial position, the master hydraulic chamber communicates with the atmospheric pressure chamber, and the master piston moves from the initial position to the first position. A first communication passage is formed in the master piston so that communication between the master hydraulic chamber and the atmospheric pressure chamber is interrupted by the seal member when the master piston is moved forward by more than a stroke. The simulator chamber communicates with the atmospheric pressure chamber when in the position, and the simulator chamber and the atmospheric pressure chamber when the master piston moves forward from the initial position by at least a second stroke larger than the first stroke. The second communication passage is connected to the master piston so that communication with the master piston is interrupted by the seal member. Stroke simulator built master cylinder, characterized in that formed in the down. The master cylinder with a built-in stroke simulator according to claim 4, wherein the simulator piston is slidably housed in the master piston.

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