JP4589015B2 - Master cylinder device - Google Patents

Description

  The present invention relates to a master cylinder device suitably used for, for example, a brake system of a vehicle brake-by-wire system.

  Generally, various brake systems are mounted on vehicles such as four-wheeled vehicles. And a configuration in which an operation amount (stroke, pedaling force, etc.) of the brake pedal is detected and a brake fluid pressure corresponding to the operation amount is supplied from a fluid pressure source such as a fluid pressure pump toward the wheel cylinder on the wheel side. A brake-by-wire brake system (hereinafter referred to as a BBW system) is known (for example, see Patent Document 1).

  In this type of prior art BBW system, for example, a master cylinder for fail-safe is provided in case of system failure, and this master cylinder is replaced with an external hydraulic pressure source when the brake pedal is depressed. And actuating to supply brake fluid pressure to the wheel cylinder.

  A fail-safe valve is provided between the master cylinder and the wheel cylinder. During normal operation of the system, the fail-safe valve shuts off the master cylinder and the wheel cylinder so that the fluid pressure source may be damaged. When the BBW system fails, the hydraulic pressure supply from the master cylinder to the wheel cylinder is enabled by opening the fail-safe valve.

  Also, in such a master cylinder, since the master cylinder and the wheel cylinder are disconnected by a fail-safe valve during normal operation of the system, the hydraulic pressure generated in the hydraulic chamber of the master cylinder due to the brake operation is reduced. A stroke simulator is provided for accumulating pressure.

  The stroke simulator accumulates the hydraulic pressure generated in the hydraulic pressure chamber and transmits the brake reaction force to the brake pedal, thereby giving the vehicle driver the pedal reaction force in the normal operation of the system. The brake is effective, so-called tread response.

JP-A-11-334577

  By the way, in the above-described prior art, there is a problem that the stroke simulator is enlarged because two types of springs, one having a large spring constant and one having a small spring constant, are accommodated in the stroke simulator. In other words, it is desirable that the feeling of operation of the brake pedal is light at the beginning of the pedal, gradually becomes heavier as the brake pedal is depressed, and gives a treading response that suddenly feels the weight when the pedal is depressed to some extent.

  In the prior art, in order to give such a feeling of operation of the brake pedal, two types of springs are accommodated in the stroke simulator, which increases the size of the stroke simulator and the entire master cylinder device including the stroke simulator. There is a problem that it is difficult to form in a compact size, and mountability to a vehicle is deteriorated.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to reduce the overall size including the stroke simulator, to be compact, and to improve the mountability to a vehicle. An object of the present invention is to provide a master cylinder device.

In order to solve the above-described problems, the present invention includes a bottomed cylindrical cylinder, a piston that is slidably provided in the cylinder and that is displaced in the axial direction in response to a brake operation, and the piston. A hydraulic chamber defined in the cylinder and connected to the wheel-side wheel cylinder via a fail-safe valve; and when the hydraulic chamber and the wheel cylinder are blocked by the fail-safe valve, by accumulating the hydraulic pressure generated in the liquid chamber by the braking operation is applied to the master cylinder device provided with a stroke simulator to generate a brake reaction.

And, characteristic of the structure of the invention of claim 1 is employed, between the liquid chamber and the stroke simulator is the fluid pressure of the fluid in the chamber reaches a predetermined set pressure by said brake operation He is from the hydraulic chamber that is configured to provide a hydraulic pressure control valve for limiting the fluid pressure supplied to the stroke simulator when.

The invention of claim 2, between the liquid chamber and the stroke simulator is normally the when the hydraulic pressure chamber is communicated with the wheel cylinders by communicating between the two said fail-safe valve the switching valve interrupting the connection between the hydraulic chamber and the stroke simulator is provided, the pressure control valve has a structure in which arranged between the switching valve and the stroke simulator.

  Furthermore, according to the invention of claim 3, the hydraulic pressure control valve is connected to a hydraulic pressure source that supplies hydraulic pressure to the wheel cylinder, and the set pressure that changes the set pressure in response to the pressure of the hydraulic pressure source. The variable means is included.

  As described above, according to the first aspect of the present invention, the hydraulic pressure control valve provided between the hydraulic pressure chamber in the cylinder and the stroke simulator is configured so that the hydraulic pressure in the hydraulic pressure chamber can be increased by, for example, depressing the brake pedal. Until the pressure reaches a predetermined set pressure, the hydraulic pressure is supplied from the hydraulic pressure chamber to the stroke simulator without limiting. For this reason, the stroke simulator generates a brake reaction force corresponding to the hydraulic pressure at this time. Then, by making the elastic body (spring) accommodated in the stroke simulator, for example, an elastic body having a small spring constant, the brake reaction force can be suppressed small, and a relatively light treading response is given to the driver of the vehicle. be able to.

  When the hydraulic pressure generated in the hydraulic pressure chamber reaches a predetermined set pressure, the hydraulic pressure supplied from the hydraulic pressure chamber to the stroke simulator is limited by the hydraulic pressure control valve. Therefore, at this time, the hydraulic pressure control valve can generate a brake reaction force together with the stroke simulator, and the brake reaction force at this time can give a sufficient step response to the driver of the vehicle, and the stroke simulator can be overloaded. The action of hydraulic pressure can also be suppressed. Therefore, it is possible to ensure a good pedal feeling (stepping response) during braking by simply accommodating an elastic body (for example, a single spring) with a small spring constant in the stroke simulator. The simulator can be reduced in size and can be made compact, and workability and assemblability when the master cylinder device is mounted on a vehicle can be improved.

  In the invention described in claim 2, since a switching valve is provided between the hydraulic chamber and the hydraulic control valve (stroke simulator), the switching valve causes the switching between the hydraulic chamber and the hydraulic control valve. When the fluid safe is opened and the hydraulic pressure is supplied from the hydraulic chamber of the cylinder to the wheel cylinder, for example, when the hydraulic pressure source fails, the hydraulic chamber and the hydraulic control valve ( The switching valve can be shut off from the stroke simulator.

  Further, in the invention described in claim 3, since the set pressure variable means is provided in the hydraulic pressure control valve, the set pressure by the hydraulic pressure control valve can be changed in correspondence with the pressure of the hydraulic pressure source. When the hydraulic pressure source fails, the hydraulic pressure supplied from the hydraulic chamber to the stroke simulator can be limited at an early stage by setting the hydraulic pressure control valve to a low pressure. The hydraulic pressure can be efficiently supplied from the hydraulic pressure chamber toward the wheel cylinder.

  Hereinafter, a case where the master cylinder device according to the embodiment of the present invention is applied to a BBW system (brake-by-wire type brake system) of a vehicle will be described as an example, and will be described in detail with reference to FIGS.

  Here, FIG. 1 to FIG. 6 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a master cylinder device according to the present embodiment. This master cylinder device 1 includes a cylinder 2, which will be described later, first and second pistons 4, 5, first, first, as shown in FIGS. 2 hydraulic chambers 8A and 8B, a tilt valve 21, a stroke simulator 22, a hydraulic pressure control valve 31, and the like.

  Reference numeral 2 denotes a cylinder that constitutes a main part of the master cylinder device 1. The cylinder 2 constitutes a so-called tandem master cylinder as shown in FIG. 2, and the inside thereof is a bottomed cylindrical cylinder hole 2A. . The cylinder 2 is provided with first and second boss portions 2B and 2C which are separated from each other in the axial direction of the cylinder hole 2A. These boss portions 2B and 2C are connected to the first and second supply ports 2D. , 2E communicate with the inside of the cylinder hole 2A.

  Reference numeral 3 denotes a reservoir as a hydraulic fluid tank in which brake fluid is accommodated. The reservoir 3 is connected to the boss portions 2B and 2C of the cylinder 2 via pipes 3A and 3B as shown in FIG. The brake fluid is replenished into the replenishment chambers 10A and 10B. Further, the reservoir 3 is provided with another pipe line 3C for supplying brake fluid to hydraulic pumps 47A and 47B described later.

  4 is a primary piston (hereinafter referred to as a first piston 4) as a piston slidably provided in the cylinder hole 2A of the cylinder 2, and 5 is located on the deeper side of the cylinder 2 than the first piston 4 is. A secondary piston (hereinafter referred to as a second piston 5) as another piston slidably provided in the cylinder hole 2A is shown. The first and second pistons 4 and 5 are spaced apart from each other in the axial direction of the cylinder hole 2A, and a return spring 18A to be described later is disposed therebetween.

  Here, as shown in FIG. 2, the first piston 4 includes a piston portion 4A slidably fitted in the cylinder hole 2A, a smaller diameter than the piston portion 4A, and an opening end side of the cylinder 2 A radial hole 4C is formed between the piston portion 4A and the shaft portion 4B. A radial hole 4C is inserted between the piston portion 4A and the shaft portion 4B. The shaft portion 4B of the first piston 4 is attached to the opening end side of the cylinder 2 in a liquid-tight state via a piston guide 6 and the like.

  The second piston 5 is also provided with an elliptical radial hole 5A through which a pin 16 described later is inserted with a gap, and this radial hole 5A is always in communication with a supply chamber 10B described later. . The radial hole 4C of the first piston 4 is always in communication with a supply chamber 10A described later.

  A brake pedal 7 is depressed by a driver or the like when the vehicle is operated. The brake pedal 7 is depressed so as to push the shaft portion 4B of the first piston 4 into the cylinder hole 2A in the axial direction. It is. A brake reaction force (pedal reaction force) to be described later is transmitted to the brake pedal 7 through the first piston 4.

  8A and 8B are first and second hydraulic chambers defined by the pistons 4 and 5 in the cylinder hole 2A. In the hydraulic chambers 8A and 8B, the pistons 4 and 5 are disposed in the cylinder hole 2A. A hydraulic pressure is generated in accordance with the displacement in the axial direction. The hydraulic pressure chambers 8A and 8B are connected to brake pipes 44A and 44B described later via first and second pipe ports 9A and 9B provided in the cylinder 2, respectively.

  Reference numerals 10A and 10B denote first and second supply chambers which are located on the outer peripheral side of the pistons 4 and 5 and are defined in the cylinder hole 2A. The supply chambers 10A and 10B are boss portions 2B and 2C of the cylinder 2, respectively. The brake fluid is replenished from the reservoir 3 through the supply ports 2D and 2E. The replenishing chambers 10A and 10B are always in communication with the radial holes 4C and 5A of the pistons 4 and 5, and are connected to and shut off from the hydraulic chambers 8A and 8B by center valves 11A and 11B described later. It is.

  Reference numerals 11A and 11B denote first and second center valves provided on the pistons 4 and 5, respectively. These center valves 11A and 11B are arranged so that the pistons 4 and 5 are axially arranged in the cylinder hole 2A (indicated by arrows in FIG. 2). The fluid pressure chambers 8A and 8B are communicated with and cut off from the supply chambers 10A and 10B in accordance with the displacement in the A and B directions).

  Here, the first center valve 11A is slidable on the outer peripheral side of the shaft portion 4B so as to come into contact with and separate from the stopper plate 12 fixed to the piston guide 6 at the initial position shown in FIG. It is pressed in the valve opening direction via the inserted stopper ring 13 and the pin 14 inserted into the radial hole 4C. At this time, a valve spring 15 disposed between a retainer 19A, which will be described later, and the center valve 11A is elastically compressed and deformed to allow the center valve 11A to open.

  Further, when the piston 4 is pushed in the direction of arrow A in FIG. 2 by the depression operation of the brake pedal 7, the contact of the stopper ring 13 with the stopper plate 12 is released, and the stopper ring 13 together with the pin 14 is indicated by the arrow. Relative movement is possible in the B direction. For this purpose, the center valve 11A is pushed in the direction indicated by the arrow B by the valve spring 15 to block the hydraulic chamber 8A from the supply chamber 10A.

  On the other hand, the second center valve 11B is pressed in the valve opening direction through pins 16 which are inserted into the radial hole 5A of the piston 5 at the initial position shown in FIG. At this time, a valve spring 17 disposed between a retainer 19B, which will be described later, and the center valve 11B is elastically compressed and deformed to allow the center valve 11B to open.

  Further, when the pistons 4 and 5 are both pushed in the direction of arrow A in FIG. 2 by the depression operation of the brake pedal 7, the piston 5 moves relative to the pin 16 fixed to the cylinder 2. The center valve 11B is pushed in the direction of arrow B by the valve spring 17, and at this time, the hydraulic chamber 8B is shut off from the replenishing chamber 10B.

  Reference numeral 18A denotes a first return spring disposed between the first piston 4 and the second piston 5 via a retainer 19A, and reference numeral 18B denotes a second piston 5 and the bottom of the cylinder 2 via the retainer 19B. The 2nd return spring arrange | positioned between these is shown. The return springs 18A and 18B always urge the pistons 4 and 5 in the direction indicated by the arrow B in FIG. 2 is returned to the initial position shown in FIG.

  20 is a fluid passage provided in the middle portion in the longitudinal direction of the cylinder 2, 21 is a tilt valve as a switching valve provided in the cylinder 2 through the fluid passage 20, and the tilt valve 21 is shown in FIG. When the second piston 5 is in the initial position as shown in FIG. 5, the second piston 5 is held in an inclined state (valve-opened state) in contact with the end surface of the piston 5, and the fluid passage 8A in the cylinder 2 passes through the fluid passage. The fluid pressure control valve 31 (stroke simulator 22), which will be described later, is communicated via 20.

  When the second piston 5 is pushed in the direction indicated by the arrow A in FIG. 2 against the return spring 18B, the tilt valve 21 is erected from the tilted state after the contact with the piston 5 is released. By switching to the state (valve closed state) and closing the fluid passage 20, the fluid pressure chamber 8A in the cylinder 2 is shut off from the fluid pressure control valve 31 (stroke simulator 22).

  Reference numeral 22 denotes a stroke simulator employed in the present embodiment. The stroke simulator 22 is a cylinder externally attached to the cylinder 2 via a hydraulic pressure control valve 31 or the like at the position of the fluid passage 20 as shown in FIG. A cylindrical case 23, a covered piston 26 as a movable partition wall, which is slidably inserted into the cylindrical case 23 and defines the pressure accumulating chamber 24 and the spring chamber 25 in the cylindrical case 23; And a spring 27 or the like as an elastic body that constantly biases the covered piston 26 toward the pressure accumulating chamber 24 side.

  The cylindrical case 23 of the stroke simulator 22 is formed with a passage 23 </ b> A that constantly communicates an output port 32 </ b> B of a hydraulic pressure control valve 31, which will be described later, with the pressure accumulation chamber 24. When the hydraulic pressure is generated in the first hydraulic pressure chamber 8A as will be described later by the brake operation, the stroke simulator 22 transmits the hydraulic pressure via the fluid passage 20, the tilt valve 21, the hydraulic pressure control valve 31, and the like. Supplied from the passage 23A side.

  At this time, the stroke simulator 22 slides and displaces the covered piston 26 by the spring 27 being bent and deformed according to the magnitude of the hydraulic pressure, and accumulates the hydraulic pressure in the accumulator chamber 24. Then, the pressure in the pressure accumulating chamber 24 becomes a brake reaction force and is transmitted from the hydraulic pressure chamber 8A in the cylinder 2 to the brake pedal 7 via the first piston 4 to generate a pedal reaction force.

  Reference numeral 28 denotes a low-pressure pipe that communicates the spring chamber 25 of the stroke simulator 22 with the reservoir 3, and one end side of the low-pressure pipe 28 is connected to the bottom side of the cylindrical case 23 via a plug 29 and the other end side. 2 is connected to the cylinder 2 via another plug 30 or the like so as to communicate with the two replenishing chambers 10B. The low-pressure pipe 28 keeps the spring chamber 25 in a low pressure (tank pressure) state by connecting the replenishment chamber 10B that is always in communication with the reservoir 3 to the spring chamber 25 of the stroke simulator 22.

  31 is a hydraulic pressure control valve provided between the hydraulic pressure chamber 8A of the cylinder 2 and the stroke simulator 22, and the hydraulic pressure control valve 31 is stroked at the position of the fluid passage 20 through the cylinder 2 as shown in FIG. The valve case 32 is provided externally together with the simulator 22, and a stepped piston 37 and a ball valve body 38 which are slidably provided in the valve case 32 are described below.

  Here, a pressure chamber 33 and a spring chamber 34 are provided in the valve case 32 of the hydraulic control valve 31 so as to be spaced apart from each other in the length direction as shown in FIG. A small-diameter insertion hole 35 is formed between them. The spring chamber 34 of the valve case 32 is closed by a lid body 36, and a breathing hole 36A is formed in the lid body 36.

  Also, the valve case 32 is connected to the hydraulic pressure chamber 8A in the cylinder 2 via the fluid passage 20 by the tilt valve 21 shown in FIG. An accumulator chamber 24 of the stroke simulator 22 and an output port 32B that is always in communication with each other via a passage 23A shown in FIG.

  When the tilt valve 21 is opened, the pressure in the fluid pressure chamber 8A becomes the input fluid pressure Pm (see FIG. 3) and is supplied to the input port 32A of the fluid pressure control valve 31. Further, in the output port 32 B of the hydraulic pressure control valve 31, an output hydraulic pressure Pr that is equal to the pressure accumulation chamber 24 of the stroke simulator 22 is generated. The output hydraulic pressure Pr becomes substantially equal to the input hydraulic pressure Pm when a later-described ball valve body 38 is open, and is higher than the input hydraulic pressure Pm when the ball valve body 38 is closed. It is usually set to a low pressure.

  37 is a stepped piston slidably provided in the valve case 32. As shown in FIG. 3, the stepped piston 37 has a large diameter portion 37A disposed in the pressure chamber 33 and a small diameter portion 37B inserted therein. It is slidably inserted in the fitting hole 35. The small diameter portion 37B of the stepped piston 37 blocks the pressure chamber 33 in the valve case 32 from the spring chamber 34 in a liquid-tight state.

  In addition, the large-diameter portion 37A of the stepped piston 37 has a valve body housing hole 37C in which a ball valve body 38, which will be described later, is movably housed, and a diameter that always communicates the inside of the valve body housing hole 37C with the pressure chamber 33. Directional passages 37D, 37D, an axial passage 37E in which a push rod 40, which will be described later, is inserted with a gap and communicates with the output port 32B in the valve body accommodation hole 37C, and between the passage 37E and the valve body accommodation hole 37C And a valve seat 37F on which the ball valve body 38 is seated.

  Reference numeral 38 denotes a ball valve element as a valve element disposed in the valve element accommodating hole 37C of the stepped piston 37. The ball valve element 38 is urged toward the valve seat 37F shown in FIG. When the stepped piston 37 is displaced in the direction of arrow C as shown in FIGS. 4 and 5, the axial passage 37E is blocked from the valve body accommodating hole 37C.

  A push rod 40 is fixed to the valve case 32 so as to be inserted into the passage 37E with a gap. The push rod 40 has a stepped piston 37 displaced in the direction of arrow D as shown in FIG. The ball valve body 38 is brought into contact with the valve spring 38 during the operation, and the ball valve body 38 is held against the valve spring 39 in an open state.

  Reference numeral 41 denotes a pressure setting spring provided in the spring chamber 34, and the pressure setting spring 41 is disposed between the small diameter portion 37 </ b> B of the stepped piston 37 and the lid body 36 via a spring receiver 42. The stepped piston 37 is urged with a spring force F in the direction indicated by the arrow D in FIG.

  Here, the stepped piston 37 receives the input hydraulic pressure Pm from the input port 32A in the pressure chamber 33 with a pressure receiving area (S1-S2) as shown in FIG. 3, and the output hydraulic pressure Pr on the output port 32B side. The pressure is received at the pressure receiving area S1. Further, the stepped piston 37 is urged in the direction of arrow D in FIG. 3 by the spring force F of the pressure setting spring 41.

  For this reason, the stepped piston 37 is held at the position shown in FIG. 3 in accordance with the following equation 1 while the input hydraulic pressure Pm is lower than the hydraulic pressure Pma shown in FIG. 6 (Pm <Pma). The When the ball valve body 38 is open, the output hydraulic pressure Pr is set to a pressure (Pm = Pr) equal to the input hydraulic pressure Pm.

  On the other hand, when the input hydraulic pressure Pm becomes equal to or higher than the hydraulic pressure Pma shown in FIG. 6 (Pm ≧ Pma), the stepped piston 37 resists the pressure setting spring 41 in accordance with the following equation (2). The ball valve body 38 is closed in the direction indicated by the arrow C in FIG. As a result, the further hydraulic pressure supply via the output port 32B of the hydraulic pressure control valve 31 is interrupted, and the output hydraulic pressure Pr becomes a pressure value (Pm ≠ Pr) different from the input hydraulic pressure Pm.

  Next, when the input hydraulic pressure Pm further increases in this state, the output hydraulic pressure Pr becomes a pressure value (Pr <Pm) lower than the input hydraulic pressure Pm. The ball valve body 38 is pushed down in the direction of arrow D, and the ball valve body 38 is opened again by the push rod 40 as shown in FIG.

  In this way, the hydraulic control valve 31 moves the stepped piston 37 after the input hydraulic pressure Pm reaches a predetermined set pressure (for example, the hydraulic pressure Pma shown in FIG. 6) (Pm> Pma). The characteristic indicated by the solid line in FIG. 6 is that the output hydraulic pressure Pr of the output port 32B rises according to the input hydraulic pressure Pm by repeatedly sliding and displacing between the valve open position shown in FIG. 5 and the valve closed position shown in FIG. It suppresses like a line.

  43A and 43B show first and second wheel cylinders provided on the vehicle wheel side as shown in FIG. 1, and the wheel cylinders 43A and 43B constitute a cylinder portion such as a drum brake or a disc brake, for example. The brake fluid pressure is supplied and discharged via the first and second brake pipes 44A and 44B shown in FIG.

  45A and 45B are first and second fail-safe valves provided in the middle of the brake pipes 44A and 44B. The fail-safe valves 45A and 45B are opened by a control signal from the control unit 51 described later (a ) To the valve closing position (b). That is, the fail-safe valves 45A and 45B are switched from the valve opening position (a) to the valve closing position (b) during normal operation of the system, and return to the valve opening position (a) when the system fails. It is.

  46A and 46B are first and second hydraulic pressure units that constitute hydraulic pressure sources for supplying hydraulic pressure to the wheel cylinders 43A and 43B. These hydraulic pressure units 46A and 46B are wheel cylinders 43A and 43B, The brake pipes 44 </ b> A and 44 </ b> B located between the fail-safe valves 45 </ b> A and 45 </ b> B are disposed between the intermediate portions of the brake pipes 44 </ b> A and 44 </ b> B and the conduit 3 </ b> C of the reservoir 3.

  The first hydraulic unit 46A is connected to the reservoir 3 via the conduit 3C as shown in FIG. 1, and connected to the discharge side of the hydraulic pump 47A via the check valve 48A. The brake fluid pressure supply valve 49A is a normally open solenoid valve, and the brake fluid pressure discharge valve 50A is a normally closed solenoid valve.

  Similarly, for the second hydraulic pressure unit 46B, a hydraulic pump 47B that is connected to the reservoir 3 via a conduit 3C and constitutes a hydraulic pressure source, and a check valve 48B is provided on the discharge side of the hydraulic pressure pump 47B. And a normally-open supply valve 49B, a normally-closed discharge valve 50B, and the like connected thereto.

  Reference numeral 51 denotes a control unit that constitutes a control device of the BBW system. The control unit 51 is constituted by, for example, a microcomputer, and the input side thereof includes an operation detector (hereinafter referred to as a pedal sensor 52) of the brake pedal 7 and a wheel. The cylinders 43A and 43B are connected to pressure sensors 53A and 53B and the like.

  In this case, the pedal sensor 52 detects a stroke or a pedaling force when the brake pedal 7 is depressed. Further, the pressure sensors 53A and 53B detect the brake fluid pressure supplied to the wheel cylinders 43A and 43B. The control unit 51 determines whether or not the BBW system is operating normally according to detection signals from the pedal sensor 52 and the pressure sensors 53A and 53B, and controls the brake fluid pressure as described later. is there.

  Further, the output side of the control unit 51 is connected to the fail safe valves 45A and 45B, the hydraulic units 46A and 46B, and the like. The control unit 51 switches the fail-safe valves 45A and 45B to the closed position (b) during normal operation of the system and supplies power to the hydraulic units 46A and 46B to operate the hydraulic pumps 47A and 47B. The supply valves 49A and 49B and the discharge valves 50A and 50B are selectively opened and closed in order to increase, hold, or reduce the brake fluid pressure of the wheel cylinders 43A and 43B.

  The BBW system using the master cylinder device 1 according to the present embodiment has the above-described configuration. Next, the operation thereof will be described.

  First, when the BBW system operates normally, the fail-safe valves 45A and 45B are switched from the valve-opening position (a) to the valve-closing position (b) shown in FIG. The hydraulic chambers 8A and 8B are cut off from the wheel cylinders 43A and 43B.

  When the brake pedal 7 is depressed during braking of the vehicle in this state, the center valve 11A is in a stage where the pistons 4 and 5 are slightly pushed in the direction of the arrow A in FIG. , 11B are closed to shut off the hydraulic chambers 8A, 8B from the supply chambers 10A, 10B.

  At this time, the second hydraulic pressure chamber 8B is shut off from the wheel cylinder 43B by the fail-safe valve 45B and also from the replenishment chamber 10B, so that the second piston 5 is in a hydraulic pressure locked state. Thus, further sliding displacement is suppressed, and the tilt valve 21 is kept in the open state illustrated in FIG.

  In the first hydraulic chamber 8A, the hydraulic pressure increases as the first piston 4 slides and displaces in the direction indicated by the arrow A. The hydraulic pressure in the hydraulic chamber 8A is the fluid passage 20, The gas is supplied into the cylindrical case 23 (pressure accumulation chamber 24) of the stroke simulator 22 through the tilt valve 21, the hydraulic pressure control valve 31, and the like.

  At this time, in the stroke simulator 22, the spring 27 in the cylindrical case 23 is bent and deformed according to the magnitude of the hydraulic pressure, and the covered piston 26 is slid and displaced, thereby accumulating the hydraulic pressure in the accumulator chamber 24. The pressure in the pressure accumulating chamber 24 becomes a brake reaction force and is transmitted from the hydraulic pressure chamber 8A in the cylinder 2 to the brake pedal 7 via the first piston 4, so that a pedal reaction force can be generated. In addition, the brake effect, so-called tread response, can be given to the driver of the vehicle.

  By the way, it is desirable that the tread response in this case is such that the start of the brake pedal 7 is light and gradually becomes heavier as the brake pedal 7 is depressed, and suddenly feels the weight when the brake pedal 7 is depressed to some extent. However, in order to give such a feeling of operation of the brake pedal 7, it is necessary to accommodate a plurality of springs having different spring constants in the stroke simulator 22, which increases the size of the stroke simulator and facilitates mounting on a vehicle. Deteriorate.

  Therefore, in the present embodiment, the hydraulic pressure control valve 31 is provided between the hydraulic pressure chamber 8A of the cylinder 2 and the stroke simulator 22, and the hydraulic pressure control is performed as indicated by the characteristic line 54 shown by the solid line in FIG. The operational feeling of the brake pedal 7 is improved and the response to the depression is kept good.

  That is, the stepped piston 37 of the hydraulic control valve 31 is illustrated in FIG. 3 until the input hydraulic pressure Pm of the hydraulic control valve 31 reaches a predetermined set pressure (for example, the hydraulic pressure Pma shown in FIG. 6). The output hydraulic pressure Pr (hydraulic pressure supplied to the pressure accumulating chamber 24 of the stroke simulator 22) on the output port 32B side is proportional to the input hydraulic pressure Pm (pressure in the hydraulic pressure chamber 8A). Increased or decreased.

  However, when the input hydraulic pressure Pm exceeds the set pressure (Pm> Pma), the stepped piston 37 of the hydraulic control valve 31 repeats between the open position shown in FIG. 3 and the closed position shown in FIG. By sliding displacement, the output hydraulic pressure Pr of the output port 32B can be controlled in two stages as shown by the characteristic line 54 shown by a solid line in FIG. 6, and the output hydraulic pressure Pr (the hydraulic pressure in the pressure accumulating chamber 24) is It is possible to suppress an increase according to the input hydraulic pressure Pm as indicated by a characteristic line 55 indicated by a one-dot chain line.

  For this reason, the covered piston 26 of the stroke simulator 22 outputs the displacement Ls as shown by the characteristic line 56 shown by the solid line in FIG. 6 until the input hydraulic pressure Pm of the hydraulic control valve 31 reaches the hydraulic pressure Pma. According to the hydraulic pressure Pr (hydraulic pressure Pra), it moves with a relatively light reaction force to the position of the displacement Lsa.

  However, after the input hydraulic pressure Pm of the hydraulic pressure control valve 31 exceeds the hydraulic pressure Pma, for example, when the input hydraulic pressure Pm is the hydraulic pressure Pmb, the output hydraulic pressure Pr (the hydraulic pressure in the pressure accumulating chamber 24) is set to the hydraulic pressure. By restricting to Prb, the stroke simulator 22 can suppress the displacement amount Ls of the covered piston 26 as a displacement amount (Lsb-Lsa), and the covered piston 26 can be quickly stroked in the cylindrical case 23 illustrated in FIG. Can be suppressed.

  As a result, the spring 27 provided between the cylindrical case 23 of the stroke simulator 22 and the covered piston 26 can be constituted by a spring having a relatively small spring constant, and the stroke simulator 22 can be made compact by reducing its size and weight. it can. A good pedal reaction force can be transmitted to the brake pedal 7 according to the input hydraulic pressure Pm (pressure in the hydraulic pressure chamber 8A) of the hydraulic pressure control valve 31, and the operational feeling of the brake pedal 7 can be improved. .

  Further, when such a brake operation is performed, the depression operation of the brake pedal 7 is detected by the pedal sensor 52, so that a control signal is output from the control unit 51 to the hydraulic units 46A and 46B to operate the hydraulic pumps 47A and 47B. In addition, the supply valves 49A and 49B and the discharge valves 50A and 50B can be selectively opened and closed.

  Therefore, when braking the vehicle, the brake hydraulic pressure supplied from the hydraulic pumps 47A, 47B to the wheel cylinders 43A, 43B can be increased, held, or reduced according to the depression operation of the brake pedal 7, and the brake pedal 7 can be depressed. The brake fluid pressure corresponding to the operation can be supplied to the wheel cylinders 43A and 43B, and the braking force control of the vehicle can be performed with high accuracy.

  On the other hand, for example, when the hydraulic pumps 47A and 47B serving as the hydraulic pressure source fail or the control unit 51 fails, the automatic brake fluid pressure control by the BBW system as described above is invalidated. When such a system failure occurs, no control signal is output from the control unit 51 to the fail-safe valves 45A and 45B, and the fail-safe valves 45A and 45B are automatically set to the valve open position (a) shown in FIG. Return.

  Therefore, in the master cylinder device 1, the hydraulic chambers 8A and 8B in the cylinder 2 are in communication with the wheel cylinders 43A and 43B. In this state, when the brake pedal 7 is depressed when the vehicle is braked or the like, the pistons 4 and 5 are both pushed in the axial direction in the cylinder hole 2A, and the center valves 11A and 11B are closed and the liquid is discharged. The pressure chambers 8A and 8B are blocked from the supply chambers 10A and 10B, and a hydraulic pressure corresponding to the depression operation of the brake pedal 7 is generated in the hydraulic pressure chambers 8A and 8B.

  The hydraulic pressure generated in the hydraulic pressure chambers 8A and 8B is supplied as brake hydraulic pressure to the wheel cylinders 43A and 43B via the brake pipes 44A and 44B. Even in this case, it corresponds to the depression operation of the brake pedal 7. Brake fluid pressure can be supplied to the wheel cylinders 43A and 43B.

  Further, in the tilt valve 21 provided between the hydraulic chamber 8A in the cylinder 2 and the hydraulic control valve 31 via the liquid passage 20, the second piston 5 resists the return spring 18B in FIG. Is pushed in the direction of arrow A, the contact with the piston 5 is released and the tilted state is switched to the upright state (valve closed state), and the fluid passage 20 is connected to the hydraulic pressure control valve 31. Block.

  Thereby, for example, when the system fails, the hydraulic pressure chamber 8A in the cylinder 2 can be shut off from the input port 32A side of the hydraulic pressure control valve 31, and the hydraulic pressure in the hydraulic pressure chamber 8A is reduced on the stroke simulator 22 side. It is possible to prevent excessive consumption and to efficiently supply the hydraulic pressure generated in the hydraulic pressure chamber 8A to the wheel cylinder 43A via the brake pipe 44A.

  Therefore, according to the present embodiment, by providing the hydraulic pressure control valve 31 between the hydraulic pressure chamber 8A in the cylinder 2 and the stroke simulator 22, the spring 27 accommodated in the stroke simulator 22 is, for example, a spring constant. The stroke simulator 22 can ensure a good pedal feeling (stepping response) when the brake is operated.

  For this reason, in this Embodiment, the stroke simulator 22 can be reduced in size and weight, and can be formed compactly. By using such a stroke simulator 22, the master cylinder device 1 as a whole can be reduced in size and weight, and workability and assembling performance when the master cylinder device 1 is mounted on a vehicle are improved. Can do.

  Next, FIG. 7 to FIG. 13 show a second embodiment of the present invention. In this embodiment, the same reference numerals are given to the same components as those in the first embodiment described above, and the description thereof will be given. Shall be omitted.

  However, the present embodiment is characterized in that the hydraulic pressure control valve 61 provided between the hydraulic pressure chamber 8A in the cylinder 2 and the stroke simulator 22 includes a set pressure variable means described later, so that the hydraulic pressure control valve 61 The setting pressure is changed according to the pressure of the hydraulic pressure source (for example, the hydraulic pressure unit 46A).

  Here, the hydraulic pressure control valve 61 is configured in substantially the same manner as the hydraulic pressure control valve 31 described in the first embodiment, and a valve case 62 having an input port 62A, an output port 62B, and the like is illustrated in FIG. 9, a pressure chamber 63, a spring chamber 64, a small-diameter insertion hole 65, and the like are formed. In the valve case 62, the stepped piston 37, the ball valve body 38, the valve spring 39, the push rod 40, the spring receiver 42 and the like described in the first embodiment are provided.

  However, in this case, the hydraulic control valve 61 has a diameter-enlarged portion 64B formed in the spring chamber 64 in the valve case 62 via an annular stepped portion 64A, and a stepped spring receiver 66 is formed in the enlarged-diameter portion 64B. Are arranged to be displaceable. A large return spring 67 is disposed between the stepped spring receiver 66 and the wall surface 64C of the spring chamber 64 as shown in FIG. A small-diameter pressure setting spring 68 is provided between the spring 37 and the spring 37.

  Here, the pressure setting spring 68 is positioned inward of the return spring 67 in the radial direction and is disposed in the spring chamber 64 in a state of compression deformation, and the stepped piston 37 is moved in the direction indicated by the arrow D in FIG. It is energized with F. As described in the first embodiment, the stepped piston 37 receives the input hydraulic pressure Pm from the input port 32A in the pressure chamber 63 with a pressure receiving area (S1-S2) as shown in FIG. The spring force F of the pressure setting spring 68 is biased in the direction indicated by the arrow D in FIG.

  Further, the stepped piston 37 is pressed in the direction indicated by the arrow C in FIG. 9 by receiving the output hydraulic pressure Pr on the output port 32B side in the pressure receiving area S1. For this reason, the stepped piston 37 has a valve opening position shown in FIG. 9 and a valve closing position shown in FIG. 10 and FIG. 11 so as to satisfy the relationship of Equations 1 and 2 described in the first embodiment. The sliding displacement is repeated between them.

  A pusher sliding hole 62C is formed in the valve case 62 of the hydraulic pressure control valve 61 in the axial direction so as to communicate with the enlarged diameter portion 64B of the spring chamber 64, and communicates with the pusher sliding hole 62C. A pilot port 62D extending in the radial direction is formed. A pusher 69 is inserted into the pusher sliding hole 62C. The pusher 69 receives a pilot pressure Po described later from the pilot port 62D, thereby causing the stepped spring receiver 66 to oppose the return spring 67. Push in the direction indicated by D.

  In this case, the pusher 69 constitutes a set pressure variable means together with the stepped spring receiver 66 and the like, and the spring force F of the pressure setting spring 68 (set pressure by the hydraulic pressure control valve 61) is as shown in FIGS. The stepped spring receiver 66 is changed to a large or small position between a position where the stepped spring receiver 66 is advanced in the direction of arrow D and a position where the stepped spring receiver 66 is moved back in the direction of arrow C as shown in FIG.

  Further, the pilot port 62D of the valve case 62 is connected to the front end side of the pilot pipe 70 as shown in FIG. 8, and the base end side of the pilot pipe 70 is connected to the wheel cylinder 43A and the fail-safe valve 45A as shown in FIG. Is branched from the middle part of the brake pipe 44A.

  The brake hydraulic pressure supplied from the hydraulic pump 47A of the hydraulic pressure unit 46A via the supply valve 49A and the like is introduced into the pilot pipe 70 as a pilot pressure Po. The pilot pressure Po is shown in FIG. The pressure is received by the pusher 69 shown in FIG.

  Thus, also in the present embodiment configured as described above, the hydraulic pressure control valve 61 is provided between the hydraulic pressure chamber 8A in the cylinder 2 and the stroke simulator 22, thereby substantially the same as the first embodiment. The effect of this can be obtained. However, in the present embodiment, since the spring force F of the pressure setting spring 68 (the set pressure by the hydraulic pressure control valve 61) is changed in at least two steps, large and small, the following effects are obtained. be able to.

  That is, while the BBW system is operating normally, the brake hydraulic pressure supplied from the hydraulic pump 47A via the supply valve 49A or the like becomes the pilot pressure Po and is led to the pilot port 62D of the valve case 62. It is burned. The pusher 69 receives the pilot pressure Po to hold the stepped spring receiver 66 at a position advanced in the arrow D direction as shown in FIGS.

  For this reason, the pressure setting spring 68 is compressed and deformed between the stepped spring receiver 66 and the small diameter portion 37B of the stepped piston 37, so that the spring force F is set to a high pressure value. As a result, the stepped piston 37 is held at the position shown in FIG. 9 in accordance with the above-described equation (1) while the input hydraulic pressure Pm is lower than the hydraulic pressure Pm2 shown in FIG. 13 (Pm <Pm2). . When the ball valve body 38 is open, the output hydraulic pressure Pr is set to a pressure (Pm = Pr) equal to the input hydraulic pressure Pm.

  On the other hand, when the input hydraulic pressure Pm becomes equal to or higher than the hydraulic pressure Pm2 shown in FIG. 13 (Pm ≧ Pm2), the stepped piston 37 opposes the pressure setting spring 68 in the relationship of the above-described equation (2). , The ball valve body 38 closes the passage 37E. As a result, the further supply of hydraulic pressure via the output port 32B of the hydraulic pressure control valve 61 is interrupted, and the output hydraulic pressure Pr becomes a pressure value (Pm ≠ Pr) different from the input hydraulic pressure Pm.

  Next, when the input hydraulic pressure Pm further increases in this state, the output hydraulic pressure Pr becomes a pressure value (Pr <Pm) lower than the input hydraulic pressure Pm. The ball valve body 38 is pushed down in the direction of arrow D and the ball valve body 38 is opened again by the push rod 40 as shown in FIG.

  In this way, the hydraulic pressure control valve 61 causes the stepped piston 37 to move to the position shown in FIG. 9 after the input hydraulic pressure Pm reaches a predetermined set pressure (for example, the hydraulic pressure Pm2 shown in FIG. 13) (Pm> Pm2). Is repeatedly slid and displaced between the valve opening position shown in FIG. 11 and the valve closing position shown in FIG. 11, and the output hydraulic pressure Pr of the output port 32B is controlled in two stages as indicated by the characteristic line 71 shown by the solid line in FIG. It is possible to prevent the output hydraulic pressure Pr (hydraulic pressure in the pressure accumulating chamber 24) from increasing according to the input hydraulic pressure Pm as indicated by a characteristic line 55 indicated by a one-dot chain line.

  Then, the covered piston 26 of the stroke simulator 22 has the displacement Ls as shown by the characteristic line 56 shown by the solid line in FIG. 13 until the input hydraulic pressure Pm of the hydraulic control valve 61 reaches the hydraulic pressure Pm2. According to the pressure Pr, it moves to the position of the displacement Ls2 with a relatively light reaction force, and thereafter, the covered piston 26 reaches the stroke end early in the cylindrical case 23 as in the first embodiment. Can be suppressed.

  On the other hand, when the system fails, the supply of the brake fluid pressure by the fluid pressure pump 47A is invalidated, so that the pilot pressure Po guided to the pilot port 62D of the valve case 62 greatly decreases as a tank pressure. . Thereby, the stepped spring receiver 66 is returned together with the pusher 69 by the return spring 67 in the direction indicated by the arrow C in FIG. 12, and the spring force F of the pressure setting spring 68 is set to a low pressure value.

  Therefore, the set pressure of the hydraulic pressure control valve 61 decreases from the hydraulic pressure Pm2 shown in FIG. 13 to a lower hydraulic pressure Pm1 (Pm1 <Pm2), and the stepped piston 37 has an input hydraulic pressure Pm of 1. When the hydraulic pressure Pm1 is reached, the passage 37E is closed by the ball valve body 38 as shown in FIG. 10, so that the output hydraulic pressure Pr on the output port 32B side is represented by a characteristic line 72 shown by a two-dot chain line in FIG. It is controlled as follows.

  Therefore, when the system fails, the fluid pressure flows from the fluid pressure chamber 8A in the cylinder 2 to the stroke simulator 22 side via the fluid pressure control valve 61. It can be shut off early by closing with the valve body 38, and the hydraulic pressure in the hydraulic chamber 8A can be prevented from being excessively consumed on the stroke simulator 22 side when the system fails, and is generated in the hydraulic chamber 8A. The hydraulic pressure can be efficiently supplied to the wheel cylinder 43A via the brake pipe 44A.

  In each of the above embodiments, the case where the fluid pressure chambers 8A and 8B in the cylinder 2 and the replenishing chambers 10A and 10B are communicated and blocked by the center valves 11A and 11B has been described as an example. However, the present invention is not limited to this, and can be applied to various types of master cylinders such as a conventional type, a plunger type, or a composite type thereof.

1 is a brake hydraulic circuit diagram showing a master cylinder device according to a first embodiment of the present invention. It is principal part sectional drawing which expands and shows the master cylinder apparatus in FIG. It is sectional drawing which expands and shows the hydraulic control valve in FIG. It is sectional drawing in the same position as FIG. 3 which shows the state which the input hydraulic pressure of the hydraulic control valve reached the setting pressure. It is sectional drawing which shows the state which the stepped piston in FIG. 4 displaced to the stalk end. It is a characteristic diagram which shows the control characteristic etc. of a hydraulic control valve. It is a brake fluid pressure circuit diagram showing the master cylinder device by a 2nd embodiment. It is principal part sectional drawing which expands and shows the master cylinder apparatus in FIG. It is sectional drawing which expands and shows the hydraulic control valve in FIG. It is sectional drawing in the same position as FIG. 9 which shows the state which the input hydraulic pressure of the hydraulic control valve reached the setting pressure. It is sectional drawing which shows the state which the stepped piston in FIG. 10 displaced to the stalk end. It is sectional drawing in the same position as FIG. 9 which shows the state which the setting pressure of the hydraulic-pressure control valve changed to the low pressure value. It is a characteristic diagram which shows the control characteristic etc. of the hydraulic control valve by 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Master cylinder apparatus 2 Cylinder 3 Reservoir 4 1st piston (piston)
5 Second piston 7 Brake pedal 8A, 8B Hydraulic chamber 10A, 10B Supply chamber 11A, 11B Center valve 18A, 18B Return spring 20 Fluid passage 21 Tilt valve (switching valve)
22 Stroke simulator 23 Cylindrical case 24 Accumulation chamber 26 Covered piston 27 Spring (elastic body)
31, 61 Hydraulic pressure control valve 32, 62 Valve case 32A, 62A Input port 32B, 62B Output port 37 Stepped piston 38 Ball valve body 40 Push rod 41, 68 Pressure setting spring 43A, 43B Wheel cylinder 44A, 44B Brake piping 45A , 45B Fail-safe valve 46A, 46B Hydraulic unit (hydraulic pressure source)
47A, 47B Hydraulic pump 49A, 49B Supply valve 50A, 50B Discharge valve 51 Control unit (control device)
62D Pilot port 66 Stepped spring holder 69 Pusher (Set pressure variable means)
70 Pilot piping

Claims (3)

A bottomed cylindrical cylinder, a piston that is slidable in the cylinder and that is displaced in the axial direction in response to a brake operation, and is defined in the cylinder by the piston as a wheel cylinder on the wheel side The hydraulic pressure generated in the hydraulic chamber by the brake operation when the hydraulic chamber connected via the fail-safe valve and the hydraulic chamber and the wheel cylinder are blocked by the fail-safe valve In a master cylinder device comprising a stroke simulator that accumulates pressure to generate a brake reaction force,
Between the hydraulic chamber and the stroke simulator is fluid pressure supplied to the stroke simulator from the hydraulic chamber when the hydraulic pressure in the hydraulic pressure chamber reaches a predetermined set pressure by said brake operation A master cylinder device characterized in that a hydraulic pressure control valve for limiting the pressure is provided. Between the hydraulic chamber and the stroke simulator, the hydraulic pressure chamber and with the stroke simulator when the hydraulic pressure chamber is communicated with the wheel cylinders by constantly communicating between the two said fail-safe valve 2. The master cylinder device according to claim 1, wherein a switching valve that cuts off a gap is provided, and the hydraulic control valve is disposed between the switching valve and the stroke simulator.   2. The hydraulic pressure control valve includes a set pressure variable unit that is connected to a hydraulic pressure source that supplies a hydraulic pressure to the wheel cylinder and that changes the set pressure in accordance with the pressure of the hydraulic pressure source. Or the master cylinder apparatus of 2.

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