Disc brake device

Abstract

To provide a disc brake device that can more reliably suppress knock-back and similar phenomena.SOLUTION: A disc brake device 1 includes a fluid passage 2 that communicates a master cylinder 7 with a brake caliper 8, wherein the fluid passage 2 is composed of a first flow passage 3 connected to a check valve 5 that permits passage of brake fluid supplied from the master cylinder 7 to the brake caliper 8, and a second flow passage 4 connected to a control valve portion 6 that permits passage of brake fluid recovered from the brake caliper 8 to the master cylinder 7, and, when pressure applied from the master cylinder 7 is released after being applied, the disc brake device 1 causes a first piston 11 to close a connection with the second flow passage 4 by a biasing force of a spring 13 in the control valve portion 6, thereby holding a fluid pressure of the second flow passage 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a disc brake device. [Background technology]

[0002] Conventionally, vehicle disc brakes have been known to experience a phenomenon in which the disc rotor sways (tilts) in the vehicle width direction during braking, for example, while driving. Generally, in disc brakes, the fluid passages between the master cylinder and the wheel cylinder (brake caliper) are always connected. Therefore, when the disc rotor sways, the disc rotor pushes the brake pads, causing the pistons to retract. This can cause a so-called knockback phenomenon. More specifically, the brake fluid in the brake circuit returns to the reservoir tank of the master cylinder, increasing the stroke of the brake pedal.

[0003] Patent Document 1 discloses a circuit in which the brake piping of the forward path and the brake piping of the return path, an inlet port, four opposing hydraulic chambers, and a fluid passage hole on the forward path side and a fluid passage hole on the return path side are connected in a ring shape, and brake fluid in the path is allowed to flow in only one direction by a one-way valve attached to the inlet port and a one-way valve integrally formed in the sealing material of the return path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 06-069048 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the circuit disclosed in Patent Document 1 only maintains the internal pressure generated by each valve, and when an external force is generated that pushes the piston back, there is a risk that the valve will open undesirably while maintaining the internal pressure.

[0006] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a disc brake device that can more reliably suppress knockback phenomena and the like. [Means for solving the problem]

[0007] The disc brake device according to the present invention comprises: A disc brake device having a fluid flow path that connects a master cylinder and a brake caliper, The liquid flow path is a first flow path connected to a check valve that allows brake fluid to pass from the master cylinder to the brake caliper; a second flow path connected to a control valve portion that allows the brake fluid to pass from the brake caliper to the master cylinder; The control valve unit a first piston that opens and closes the connection with the second flow path; a second piston capable of transmitting a biasing force in a closing direction to the first piston and having a larger diameter than the first piston; a spring that biases the first piston in a closing direction via the second piston; a space provided between the first piston and the second piston and communicating with the first flow path; When the pressure is released from the master cylinder after being pressurized, the first piston closes the connection with the second flow path by the biasing force of the spring, thereby maintaining the hydraulic pressure in the second flow path. It is a disc brake device.

[0008] Further, the disc brake device according to the present invention is A disc brake device having a fluid flow path that connects a master cylinder and a brake caliper, The liquid flow path is a first flow path connected to a check valve that allows brake fluid to pass from the master cylinder to the brake caliper; a second flow path connected to a control valve portion that allows the brake fluid to pass from the brake caliper to the master cylinder; The control valve unit a first piston that opens and closes the connection with the second flow path; a second piston capable of transmitting a biasing force in a closing direction to the first piston and having a larger diameter than the first piston; a spring that biases the first piston in a closing direction via the second piston; a space provided between the first piston and the second piston and communicating with the first flow path; When the pressure from the master cylinder is released after being pressurized, the first piston closes the connection with the second flow path by the biasing force of the spring, thereby maintaining the hydraulic pressure in the second flow path, a solenoid capable of storing the spring; The solenoid is a push rod that energizes the spring when energized; a return spring that releases the force stored in the spring of the push rod when the current supply is stopped. It is a disc brake device. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a disc brake device that can more reliably prevent knockback and other phenomena.

[0010] The present invention has been briefly described above. The details of the present invention will become clearer by reading the following detailed description of the invention (hereinafter referred to as "embodiments") with reference to the accompanying drawings. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view of a disc brake device according to one embodiment of the present invention, showing the solenoid in an on state and the control valve unit in a closed state. [Figure 2] FIG. 2 is a schematic cross-sectional view of the disc brake device shown in FIG. 1, showing the solenoid in an on state and the control valve unit in an open state. [Figure 3] FIG. 3 is an enlarged view of a main part of FIG. [Figure 4] FIG. 4 is an enlarged view of the main part of FIG. [Figure 5] FIG. 5 is a diagram for explaining an example of operation of the disc brake device when the brake pedal is depressed. [Figure 6] FIG. 6 is a diagram for explaining an example of the operation of the disc brake device when the brake pedal is released. [Figure 7] FIG. 7 is a schematic cross-sectional view of the disc brake device shown in FIG. 1, showing the solenoid in an off state. [Figure 8] FIG. 8 is a diagram showing a modified example of the first piston. DETAILED DESCRIPTION OF THE INVENTION

[0012] A disc brake device 1 according to one embodiment of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiment, and modifications, improvements, etc. are possible as appropriate. In addition, the material, shape, dimensions, number, location, etc. of each component in the following embodiment are arbitrary and not limited as long as they can achieve the present invention.

[0013] For example, the brake caliper 8 is supported by a wheel support member (not shown) and is disposed across a disc rotor (not shown) that is fixed to the hub of an axle (not shown) and rotates together with the wheel. A pair of wheel cylinders (not shown) are formed within the brake caliper 8, and each wheel cylinder houses a caliper piston (not shown). When each wheel cylinder receives hydraulic pressure generated by the master cylinder 7 via the hydraulic flow path 2, it displaces toward the disc rotor and presses against a pad, applying a braking force to the disc rotor.

[0014] First, the general configuration of the disc brake device 1 will be described. FIG. 1 is a schematic cross-sectional view of a disc brake device 1 according to one embodiment of the present invention, showing that the solenoid 9 is in an on state and the control valve unit 6 is in a closed state. FIG. 2 is a schematic cross-sectional view of the disc brake device 1 shown in FIG. 1, showing that the solenoid 9 is in an on state and the control valve unit 6 is in an open state. FIG. 3 is an enlarged view of a main part of FIG. 1. FIG. 4 is an enlarged view of a main part of FIG. 2. FIG. 5 is a diagram for explaining an example of operation of the disc brake device 1 when the brake pedal is depressed. FIG. 6 is a diagram for explaining an example of operation of the disc brake device 1 when the brake pedal is released. FIG. 7 is a schematic cross-sectional view of the disc brake device 1 shown in FIG. 1, showing that the solenoid 9 is in an off state.

[0015] As shown in Figures 1 and 2, the disc brake device 1 has a fluid flow path 2 that connects a master cylinder 7 and a brake caliper 8. The fluid flow path 2 is made up of a first flow path 3 connected to a check valve 5 that allows brake fluid to be supplied from the master cylinder 7 to the brake caliper 8, and a second flow path 4 connected to a control valve unit 6 that allows brake fluid to be recovered from the brake caliper 8 to the master cylinder 7.

[0016] In this example, as shown in Figures 5 and 6, the liquid flow path 2 is composed of a pair of pipes (first pipe 21 and second pipe 22) arranged side by side with a gap in the left-right direction of the paper and extending in the up-down direction of the paper, and a pair of connecting pipes (first connecting pipe 23 and second connecting pipe 24) connecting the pair of pipes so that they communicate with each other (left-right direction of the paper).

[0017] 5 and 6, the first pipe 21 is provided with a check valve 5, which divides the first pipe 21 into two regions (a first region 21a and a second region 21b) in the vertical direction of the page, sandwiching the check valve 5. In the liquid flow path 2, the first region 21a is connected to the master cylinder 7.

[0018] 5 and 6, the second pipe 22 is provided with a control valve unit 6, which divides the second pipe into two regions (a third region 22a and a fourth region 22b) in the vertical direction of the drawing, sandwiching the control valve unit 6. In the liquid flow path 2, the third region 22a is connected to the brake caliper 8. The third region 22a has a smaller diameter than the fourth region 22b, and therefore a connection point 22c between these two regions functions as a valve seat on which a valve body 11b of the first piston 11, which will be described later, seats or separates.

[0019] 5 and 6, the first connecting pipe 23 is provided to communicate between the second region 21b and the third region 22a. Therefore, the brake fluid supply path is a path including the first region 21a (first flow path 3), the second region 21b, the first connecting pipe 23, and the third region 22a.

[0020] 5 and 6, the second connecting pipe 24 is provided to communicate between the first region 21a and the fourth region 22b. Therefore, the brake fluid recovery path is a path including the third region 22a (second flow path 4), the fourth region 22b, the second connecting pipe 24, and the first region 21a.

[0021] The check valve 5 is a check valve that only allows brake fluid to pass from the master cylinder 7 to the brake caliper 8. The shape of the check valve 5 is not particularly limited, but may be, for example, the shape shown in FIG.

[0022] The control valve unit 6 is configured to only allow the brake fluid to pass from the brake caliper 8 to the master cylinder 7. As shown in FIGS. 1 and 2, the control valve unit 6 has a first piston 11, a second piston 12, a spring 13, and a space 14. Furthermore, the control valve unit 6 has a stopper 16.

[0023] The first piston 11 has a function of opening and closing the connection with the second flow path 4. In other words, the first piston 11 controls the passage of brake fluid from the third region 22a to the fourth region 22b by being seated on or separated from a connection point 22c (see FIGS. 5 and 6) between the third region 22a and the fourth region 22b.

[0024] As shown in FIGS. 3 and 4, the first piston 11 is integrally formed with a cylindrical body 11a and a hemispherical valve element 11b provided at the tip of the body 11a (the lower end of the drawing). The body 11a is provided with a hole 11c into which a rod 15 of the second piston 12 (described later) is fitted. The body 11a also has a through-hole 11d through which brake fluid can pass when the connection with the second flow path 4 is opened (see FIGS. 2 and 4). The shape of the through-hole 11d is not particularly limited, but may be, for example, the shape shown in FIG. 1. The valve element 11b is seated on or separated from a connection point 22c between the third region 22a and the fourth region 22b. That is, when the valve element 11b is seated on the connection point 22c, the second flow path 4 is closed (valve closed state), and when the valve element 11b is separated from the connection point 22c, the second flow path 4 is opened (valve open state).

[0025] A part of the outer diameter of the first piston 11 is smaller than the inner diameter of the fourth region 22b. Therefore, when the first piston 11 is in an open state, the brake fluid passes between the outer periphery of the first piston 11 and the inner periphery of the fourth region 22b and through the through-hole 11d.

[0026] The second piston 12 has a function of transmitting a biasing force in the closing direction (downward in the plane of the drawing) to the first piston 11. As shown in FIGS. 1 and 2, the second piston 12 integrally includes a biased portion 12a that abuts against the spring 13 and is biased by the spring 13, and a rod portion 15 that can bias the first piston 11 in the closing direction. That is, the biased portion 12a of the second piston 12 is biased in the closing direction by the spring 13, and the rod portion 15 accordingly biases the first piston 11 in the closing direction, thereby transmitting the biasing force in the closing direction from the spring 13 to the first piston 11.

[0027] As shown in Fig. 1, the outer diameter of the second piston 12 (the biased portion 12a), i.e., the seal diameter D, is larger than the outer diameter of the first piston 11, i.e., the seal diameter d. This allows a difference to be created between the pressure-receiving area A1 of the first piston 11 and the pressure-receiving area A2 of the second piston 12. As a result, knockback and other phenomena can be more reliably prevented, as will be described in detail below.

[0028] 1 and 2, the spring 13 is disposed between the biased portion 12a of the second piston 12 and the push rod 17 of the solenoid 9, and biases the force stored in the push rod 17 onto the biased portion 12a of the second piston 12. In other words, the spring 13 has the function of biasing the first piston 11 in the closing direction via the second piston 12.

[0029] 1 and 2, the space 14 is provided between the first piston 11 and the second piston 12. That is, the space 14 is located in the fourth region 22b and communicates with the first region 21a (first flow path 3) via the second connecting pipe 24.

[0030] 1 and 2, the stopper 16 is disposed above the second pipe 22 in the drawing, between the biased portion 12a of the second piston 12 and the solenoid 9. The stopper 16 is formed, for example, in a cylindrical shape, and the spring 13 is disposed in the cylindrical space. The stopper 16 has the function of restricting excessive backward movement (displacement toward the upper side of the drawing) of the second piston 12.

[0031] 1 to 2 and 7, the disc brake device 1 further includes a solenoid 9 capable of storing energy in the spring 13. The solenoid 9 has a push rod 17 that can store energy in the spring 13 when energized (i.e., the solenoid 9 is in an on state) as shown in FIGS. 1 and 2, and a return spring 18 that releases the stored energy of the push rod 17 relative to the spring 13 when energized (i.e., the solenoid 9 is in an off state) as shown in FIG. 7. The solenoid 9 is, for example, a known solenoid, and is controlled so that it is energized when a knockback phenomenon is likely to occur, such as during cornering braking while traveling (see FIGS. 1 and 2), and is otherwise deenergized (see FIG. 7). When the solenoid 9 is in the off state and no hydraulic pressure is applied, the spring 13 is in a free length state (unenergized state), and therefore the second piston 12 is not urged in the closing direction by the spring 13; in other words, the rod portion 15 does not urge the first piston 11 in the closing direction, and therefore the first piston 11 does not block the second flow path 4, and the disc brake device 1 operates in the same way as a normal brake.

[0032] The above has described the general configuration of the disc brake device 1. This disc brake device 1 is configured such that when pressure is applied from the master cylinder 7 and then released, the biasing force of the spring 13 causes the first piston 11 to close the connection with the second flow path 4, thereby maintaining the hydraulic pressure in the second flow path 4.

[0033] Next, an example of operation of the disc brake device 1 will be described. When the brake pedal (not shown) is depressed, the brake fluid is pressurized in the pressure-boosting chamber of the master cylinder 7, flows into the first region 21a, passes through the check valve 5, and is supplied to the brake caliper 8 via the second region 21b, the first connecting pipe 23, and the third region 22a (see FIG. 5). At this time, the hydraulic pressure of the brake fluid that has flowed into the first region 21a is transmitted to the space 14 (fourth region 22b) via the second connecting pipe 24. The hydraulic pressure transmitted to the space 14 causes the first piston 11 to close the second flow path, thereby preventing the transmission of hydraulic pressure and brake fluid to the second flow path 4. Meanwhile, the second piston 12 is moved backward by the hydraulic pressure transmitted to the space 14. The hydraulic pressure transmitted to the space 14 is then transmitted to the second region 21b via the check valve 5.

[0034] When the brake pedal is released (the brake is released), the second piston 12, which had been retracted, moves forward (displaces downward in the drawing) at the point in time when the following formula (1) is established, and the connection between the first flow path 3 and the second flow path 4 is appropriately closed. As a result, the fluid pressure on the second flow path 4 side (internal pressure P1 of the brake caliper 8) is maintained. At this time, the fluid pressure on the second flow path 4 side (in this example, the second region 21b, the third region 22a, and the first connecting pipe 23) is equal to the fluid pressure in the brake caliper 8, and the fluid pressure on the first flow path 3 side (in this example, the first region 21a, the fourth region 22b, and the second connecting pipe 24) is equal to the fluid pressure in the master cylinder 7.

[0035] P1 <F / A2···(1) P1: Internal pressure of brake caliper 8 A2: Pressure-receiving area of ​​the second piston 12 F: biasing force of spring 13

[0036] More specifically, when the brake pedal is released, the internal pressure P1 of the brake caliper 8 increases, and accordingly, the first piston 11 opens (because the second piston 12 is retracted), releasing the hydraulic pressure on the second flow path 4 side to the first flow path 3 side. At this time, the internal pressure P1 of the brake caliper 8 is transmitted to the space 14, and the second piston 12 (the biased portion 12a) is subjected to a force (a retreating force) due to the internal pressure P1 of the brake caliper 8 and a biasing force F (a forward force). During this decompression process, when the force (a force that retracts the second piston 12) due to the internal pressure P1 of the brake caliper 8 applied to the second piston 12 falls below the biasing force F of the spring 13 (i.e., formula (1) is established), the second piston 12, which had been retracted, advances due to the biasing force F of the spring 13, and the valve body 11b is seated against the connection point 22c. As a result, the first piston 11 closes, and the internal pressure P1 of the brake caliper 8 is maintained.

[0037] During the decompression process, the brake fluid flows from the brake caliper 8 into the third region 22a, passes through the control valve unit 6, passes through the fourth region 22b, the second connecting pipe 24, and the first region 21a in that order, and is then collected in the master cylinder 7 (see Figure 6).

[0038] When so-called knockback is about to occur while the internal pressure P1 of the brake caliper 8 is maintained, the control valve unit 6 maintains the closed state of the first piston 11 until the following formula (2) is established.

[0039] P2>F / A1···(2) P2: Check pressure A1: Pressure-receiving area of ​​the first piston 11

[0040] More specifically, when so-called knockback occurs, the piston of the brake caliper 8 is pushed back, and the internal pressure P1 of the brake caliper 8 tries to increase. At this time, the first piston 11 is subjected to a biasing force F (a force in the closing direction) and a force due to the internal pressure P1 of the brake caliper 8 (a force in the opening direction). However, the closed valve state of the first piston 11 is maintained until the force due to the internal pressure P1 of the brake caliper 8 reaches the check pressure P2. As a result, the knockback phenomenon is suppressed.

[0041] As described above, according to the disk brake device 1 of this example, since the pressure receiving area A2 of the second piston 12 is larger than the pressure receiving area of the first piston 11, as can be seen from equations (1) and (2), P1 < P2 holds. That is, since the check pressure P2 is larger than the internal pressure P1 of the brake caliper when the first piston 11 is closed, the closed valve state of the first piston 11 is more reliably maintained. As a result, the disk brake device 1 more reliably suppresses the knockback phenomenon.

[0042] On the other hand, due to thermal expansion of the brake pad or brake disk, etc., it is expected that the internal pressure P1 will increase when the brake is released. Therefore, when a certain pressure is reached, the pressure can be released to prevent the temperature of the brake caliper 8 from rising, etc. That is, the check pressure P2 is appropriately set in consideration of various predicted circumstances.The adjustment of this check pressure P2 is performed by appropriately adjusting the biasing force F by controlling the solenoid 9 or the like.

[0043] The disk brake device 1 of this example has been described above. Here, a modified example of the first piston will be described. FIG. 8 is a diagram showing a modified example of the first piston.

[0044] In the above example, the first piston 11 is formed by the body portion 11a and the valve body 11b, but as shown in FIG. 8, the first piston 11A may be formed in a spherical shape. In this case, the hemispherical portion on the tip side (lower side of the drawing) of the first piston 11A functions as the valve body. Note that the first piston is not limited to these shapes as long as the invention can be carried out. Modified examples of the first piston have been described above.

[0045] Here, the features of the above-described embodiments of the disc brake device according to the present invention will be briefly summarized and listed below.

[0046] [1] A disc brake device (1) having a fluid flow path (2) that communicates between a master cylinder (7) and a brake caliper (8), The liquid flow path (2) is a first flow path (3) connected to a check valve (5) that allows brake fluid to pass from the master cylinder (7) to the brake caliper (8); a second flow path (4) connected to a control valve portion (6) that allows the brake fluid to pass from the brake caliper (8) to the master cylinder (7) and be recovered; The control valve unit (6) a first piston (11) that opens and closes the connection with the second flow path (4); a second piston (12) capable of transmitting a biasing force in a closing direction to the first piston (11) and having a larger diameter than the first piston; a spring (13) that biases the first piston (11) in a closing direction via the second piston (12); a space (14) provided between the first piston (11) and the second piston (12) and communicating with the first flow path (3); When the pressure from the master cylinder (7) is released after being applied thereto, the first piston (11) closes the connection with the second flow path (4) due to the biasing force of the spring (13), thereby maintaining the hydraulic pressure in the second flow path (4). Disc brake device (1).

[0047] [2] A disc brake device (1) having a fluid flow path (2) that communicates between a master cylinder (7) and a brake caliper (8), The liquid flow path (2) is a first flow path (3) connected to a check valve (5) that allows brake fluid to pass from the master cylinder (7) to the brake caliper (8); a second flow path (4) connected to a control valve portion (6) that allows the brake fluid to pass from the brake caliper (8) to the master cylinder (7) and be recovered; The control valve unit (6) a first piston (11) that opens and closes the connection with the second flow path (4); a second piston (12) capable of transmitting a biasing force in a closing direction to the first piston (11) and having a larger diameter than the first piston; a spring (13) that biases the first piston (11) in a closing direction via the second piston (12); a space (14) provided between the first piston (11) and the second piston (12) and communicating with the first flow path (3); When the pressure from the master cylinder (7) is released after being applied thereto, the first piston (11) closes the connection with the second flow path (4) by the biasing force of the spring (13), thereby maintaining the hydraulic pressure in the second flow path (4). a solenoid (9) capable of storing the spring (13); The solenoid (9) a push rod (17) that energizes the spring (13); and a return spring (18) that releases the force stored in the spring (13) of the push rod (17) when the current supply is stopped. Disc brake device (1).

[0048] According to the configurations [1] and [2] above, when the master cylinder is pressurized and then released, the first piston closes the connection to the second flow path due to the biasing force of the spring, thereby maintaining the hydraulic pressure in the second flow path. More specifically, when the master cylinder is pressurized, brake fluid flows through the first flow path, passing through the check valve, and into the brake caliper. At this time, the brake fluid flows into the space between the first piston and the second piston, pressurizing it. As a result, the second piston retracts while the first piston closes the second flow path. Thereafter, when the master cylinder is pressurized and then released, the second piston may have retracted, so the hydraulic pressure in the second flow path opens the first piston, releasing the hydraulic pressure in the second flow path to the first flow path. In this state, the second piston remains retracted due to the hydraulic pressure in the second flow path. Then, the hydraulic pressure in the second flow path decreases, and at some point the biasing force of the spring becomes greater than the hydraulic pressure in the second flow path acting on the second piston. This causes the second piston to move forward and urge the first piston in the closing direction. That is, the first piston closes the connection with the second flow path due to the spring's urging force. This maintains the hydraulic pressure in the second flow path. If knockback occurs in this state, the hydraulic pressure in the second flow path will tend to rise, and the first piston will be subjected to both the urging force from the spring and the hydraulic pressure in the second flow path. However, the first piston will maintain the valve closed state until the hydraulic pressure in the second flow path reaches a check pressure determined by the spring's urging force and the pressure-receiving area of ​​the first piston. That is, by appropriately adjusting the pressure-receiving area and urging force of the first piston, the valve closed state of the first piston can be appropriately maintained. As a result, this configuration can prevent the knockback phenomenon.

[0049] Furthermore, with the configuration of [2] above, the amount of energy stored in the spring can be adjusted by the solenoid, which makes it possible to more reliably prevent knockback.

[0050] [3] In the disc brake device (1) described in the above [1] or [2], The second piston (12) A rod portion (15) is provided which can bias the first piston in a closing direction. Disc brake device (1).

[0051] According to the configuration [3] above, since the rod portion is provided on the second piston, the first piston can be biased in the closing direction with a simple structure. That is, this configuration makes manufacturing easier.

[0052] [4] In the disc brake device (1) described in [3] above, The first piston (11) The rod portion (15) has a hole (11c) into which the rod portion (15) is fitted. Disc brake device (1).

[0053] According to the configuration [4] above, by providing a hole in the first piston into which the rod portion fits, rotation of the first piston about the rod portion as a central axis is prevented regardless of the shape of the first piston. In other words, according to this configuration, the state in which the second flow path is closed by the first piston (valve closed state) is more appropriately maintained.

[0054] [5] In the disc brake device (1) described in [4] above, The first piston (11) a through-hole (11d) through which the brake fluid can pass when the connection with the second flow path (4) is opened; Disc brake device (1).

[0055] According to the configuration [5] above, by providing a through hole in the first piston, the so-called permeability of the brake fluid passing through the control valve portion is improved when recovering the brake fluid to the master cylinder compared to when the first piston does not have a through hole.

[0056] [6] In the disc brake device (1) described in [5] above, The first piston (11) A cylindrical body (11a) and a hemispherical valve body (11b) provided at the tip of the body (11a) are integrally formed. Disc brake device (1).

[0057] According to the configuration [6] above, the first piston is integrally formed by the body and the valve body, which allows the first piston to more appropriately maintain the second flow path closed (valve closed state) with a simple structure.

[0058] [7] In the disc brake device (1) described in [5] above, The first piston (11) has a spherical shape. Disc brake device (1).

[0059] According to the configuration [7] above, the first piston has a spherical shape, and therefore the state in which the second flow path is closed by the first piston (valve closed state) can be more appropriately maintained with a simple structure. [Explanation of symbols]

[0060] 1 Disc brake device 2 Liquid flow path 3 First flow path 4 Second flow path 5 Check valve 6 Control valve section 7 Master cylinder 8 Brake calipers 9 Solenoid 11,11A First piston 11a Torso 11b Valve body 11c Hole 11d through hole 12 Second piston 13 Spring 14 Space 15 Rod section

Claims

1. A disc brake device having a fluid flow path that connects a master cylinder and a brake caliper, The liquid flow path is a first flow path connected to a check valve that allows brake fluid to pass from the master cylinder to the brake caliper; a second flow path connected to a control valve portion that allows the brake fluid to pass from the brake caliper to the master cylinder; The control valve unit a first piston that opens and closes the connection with the second flow path; a second piston capable of transmitting a biasing force in a closing direction to the first piston and having a larger diameter than the first piston; a spring that biases the first piston in a closing direction via the second piston; a space provided between the first piston and the second piston and communicating with the first flow path; When the pressure is released from the master cylinder after being pressurized, the first piston closes the connection with the second flow path by the biasing force of the spring, thereby maintaining the hydraulic pressure in the second flow path. Disc brake device.

2. A disc brake device having a fluid flow path that connects a master cylinder and a brake caliper, The liquid flow path is a first flow path connected to a check valve that allows brake fluid to pass from the master cylinder to the brake caliper; a second flow path connected to a control valve portion that allows the brake fluid to pass from the brake caliper to the master cylinder; The control valve unit a first piston that opens and closes the connection with the second flow path; a second piston capable of transmitting a biasing force in a closing direction to the first piston and having a larger diameter than the first piston; a spring that biases the first piston in a closing direction via the second piston; a space provided between the first piston and the second piston and communicating with the first flow path; When the pressure from the master cylinder is released after being pressurized, the first piston closes the connection with the second flow path by the biasing force of the spring, thereby maintaining the hydraulic pressure in the second flow path, a solenoid capable of storing the spring; The solenoid is a push rod that energizes the spring when energized; a return spring that releases the force stored in the spring of the push rod when the current supply is stopped. Disc brake device.

3. The disc brake device according to claim 1 or 2, The second piston is a rod portion capable of biasing the first piston in a closing direction; Disc brake device.

4. The disc brake device according to claim 3, The first piston is The rod portion has a hole portion into which the rod portion is fitted. Disc brake device.

5. The disc brake device according to claim 4, The first piston is a through hole through which the brake fluid can pass when the connection with the second flow path is opened; Disc brake device.

6. The disc brake device according to claim 5, The first piston is A cylindrical body and a hemispherical valve body provided at the tip of the body are integrally formed. Disc brake device.

7. The disc brake device according to claim 5, The first piston has a spherical shape. Disc brake device.

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