JP4176669B2 - Parking brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain an automatic parking brake state with simple structure without consuming electric power. <P>SOLUTION: The parking brake state is obtained by advance actuation of a parking piston 24 in accordance with action of control hydraulic for parking. On the back of it, in a casing 23, a lock mechanism 25 is provided to mechanically lock the parking piston 24 at an advanced position for automatic lock actuation in accordance with advance actuation of the parking piston 24, and cancel the locking in accordance with action of control hydraulic for cancellation of parking. The lock mechanism 25 is disposed on the back of the parking piston 24, having an axial line perpendicular to the axial line of the parking piston 24. It includes a lock piston 30 to add energization force forward to the parking piston 24 at the time of advance actuation of the parking piston 24 at least. Both ends parts of the lock piston 30 are slidably engaged and supported at the casing 23. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a parking brake device, and more particularly, to a parking brake device that obtains a parking brake state by locking a brake piston in a hydraulic pressure operating state.

Such a parking brake device is already known from, for example, Patent Document 1 and Patent Document 2.
Japanese National Patent Publication No. 10-512947 JP 2000-504811 A

  By the way, in the said patent document 1, while a brake piston is divided | segmented into a front part and a rear brake piston, between the transmission member contact | abutted to the front end of a rear brake piston, and the obstruction board fixed to a front brake piston. A latch that can be engaged with an internal tooth engraved on the inner surface of the brake caliper behind the front brake piston with a spring contracted is engaged with the internal tooth when the transmission member is in contact with the front end of the rear brake piston. However, when the transmission member moves relatively forward from the front end of the rear brake piston, it is housed in the brake caliper so as to be disengaged from the internal teeth by a spring biasing force, An auxiliary piston that can move the member in the axial direction relative to the rear brake piston is slidably fitted. However, internal teeth must be engraved on the inner surface of the brake caliper, and the latch is housed in the brake caliper while dividing the brake piston into the front and rear brake pistons. It becomes complicated.

  Further, in Patent Document 2, an adjustment nut is screwed onto an adjustment bolt whose front end is fixedly connected to a brake piston, and an electromagnet that exerts electromagnetic force that frictionally engages the adjustment nut with a casing is provided on the adjustment nut. The brake caliper is arranged behind the brake caliper. When the parking brake state is obtained, the brake piston is moved backward by frictionally engaging the adjusting nut with the casing by the electromagnet while the brake fluid pressure is applied to the brake piston. I try to prevent it. However, it is necessary to store the electromagnet in the brake caliper, which not only complicates the structure, but also requires that the energization state of the windings of the electromagnet be maintained in the parking brake state, resulting in an increase in power consumption.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a parking brake device that can obtain a parking brake state with a simple structure that does not involve power consumption.

In order to achieve the above object, the invention according to claim 1 is slidably fitted to the casing so that the parking brake state can be obtained by the forward operation according to the action of the control fluid pressure for parking on the back side. The parking piston is automatically locked in response to the forward movement of the parking piston and mechanically locked in response to the operation of the parking release control hydraulic pressure so as to mechanically lock the parking piston in the forward position. to obtain a lock mechanism provided in front Symbol casing by way, the hydraulic pressure generating source, the generation liquid the parking control fluid pressure to control the pressure and the parking release control fluid pressure of the liquid pressure generating source and a possible and the fluid pressure control means, the locking mechanism after the parking piston is disposed in the rear of the parking piston A lock piston axially opposite end portions to the casing as slidable in the direction perpendicular to the axis of the parking piston fitted, is supported with engaged, this locking piston, while the axial direction of the lock piston The parking piston can be held at a lock operating position that locks the parking piston by applying a forward biasing force to the parking piston at least during the forward operation of the parking piston. In the operating position, the reaction force acting on the axially intermediate portion of the lock piston from the rear end of the parking piston is supported at both ends by the casing, and the invention according to claim 2 is characterized in that the invention according to claim 2 In addition to the above feature of the invention, one end of the lock piston in the axial direction is formed with a smaller diameter than the other end. To the one end, the which faces the parking release control fluid pressure to be introduced for the parking release control fluid pressure chamber, between the one end and the other end of the locking piston is connected with the tapered portion It is characterized by that.

  According to the first aspect of the present invention, when the parking control hydraulic pressure is applied to the back side of the parking piston, the parking piston moves forward and the lock mechanism mechanically locks the advance position of the parking piston. The state can be obtained automatically, and when releasing the parking brake state, the parking release control hydraulic pressure should be applied to the lock mechanism. In the parking brake state, the parking brake has a simple structure that does not consume power. You can get the status automatically.

In addition, the lock mechanism is disposed behind the parking piston, engages with the rear end of the parking piston, and is slidable in a direction perpendicular to the axis of the parking piston. The lock piston is biased to one side in the axial direction of the lock piston so that a forward biasing force is applied to the parking piston when the parking piston moves forward. The parking piston can be held at a lock operation position that locks the parking piston. At the lock operation position, a reaction force that acts on the axial intermediate portion of the lock piston from the rear end of the parking piston is applied to both axial ends of the lock piston. because it is possible to doubly supported in the casing so as to disperse, in a casing Avoiding the thickness increase for the strength increase of the portion which supports the Kkupisuton weight can be achieved by, also in part for housing the locking piston in the casing, and a relatively short length of the parking piston axis The axial direction of the casing can be shortened.

  Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.

  1 to 3 show an embodiment of the present invention. FIG. 1 is a hydraulic circuit diagram of a vehicle brake device, FIG. 2 is a longitudinal sectional view of a disc brake during non-parking brake, and FIG. FIG. 4 is a cross-sectional view corresponding to FIG. 3 in a parking brake state.

  First, in FIG. 1, the tandem master cylinder M includes first and second output ports 1A and 1B that generate brake fluid pressure in accordance with the pedaling force applied to the brake pedal P by the vehicle driver, and the first output. The port 1A is connected to the first output hydraulic pressure path 3A, and the second output port 1B is connected to the second output hydraulic pressure path 3B.

  The first output hydraulic pressure path 3A is connected to the first hydraulic pressure path 20A via a cut valve 17A that is a normally open type electromagnetic valve, and the second output hydraulic pressure path 3B is a cut valve that is a normally open type electromagnetic valve. It is connected to the second hydraulic pressure path 20B via 17B.

  The first hydraulic path 20A is connected to the left front wheel wheel brake 2A, which is a disc brake with a parking brake mechanism, via an inlet valve 6A, which is a normally open solenoid valve, and is an inlet valve, which is a normally open solenoid valve. 6B is connected to a wheel brake 2B for the right rear wheel, which is a disc brake. The second hydraulic pressure path 20B is connected to a right front wheel wheel brake 2C, which is a disc brake with a parking brake mechanism, via an inlet valve 6C, which is a normally open solenoid valve, and is an inlet, which is a normally open solenoid valve. It is connected to a wheel brake 2D for the left rear wheel, which is a disc brake, via a valve 6D. Further, check valves 7A to 7D are connected in parallel to the respective inlet valves 6A to 6D.

  Outlet valves 9A and 9B, which are normally closed solenoid valves, are provided between the first reservoir 8A corresponding to the first hydraulic pressure path 20A and the left front wheel brake 2A and the right rear wheel brake 2B, respectively. Outlet valves 9C and 9D, which are normally closed solenoid valves, are provided between the second reservoir 8B corresponding to the second hydraulic pressure path 20B and the right front wheel brake 2C and the left rear wheel brake 2D, respectively.

  The first and second reservoirs 8A, 8B allow the brake fluid to flow to the pump 10A, 10B side on the suction side of the first and second pumps 10A, 10B driven by the common electric motor 11. The directional valves 19A and 19B are connected. The first and second output hydraulic pressure paths 3A and 3B are connected between the first and second pumps 10A and 10B and the one-way valves 19A and 19B via suction valves 18A and 18B which are normally closed solenoid valves. The first and second hydraulic pressure paths 20A and 20B are connected to the discharge sides of the first and second pumps 10A and 10B via the first and second dampers 13A and 13B.

  During normal braking in which each wheel is not likely to lock, each inlet valve 6A to 6D is demagnetized and opened, and each outlet valve 9A to 9D is demagnetized and closed. The brake hydraulic pressure output from the 1 output port 1A acts on the left front wheel and right rear wheel brakes 2A and 2B via the inlet valves 6A and 6B. The brake hydraulic pressure output from the second output port 1B of the master cylinder M acts on the right front wheel brakes 2C and 2D via the inlet valves 6C and 6D.

  When the wheel is about to enter the locked state during the braking, the inlet valve corresponding to the wheel that is about to enter the locked state among the inlet valves 6A to 6D is excited and closed, and the outlet valves 9A to 9D. Of these, the outlet valve corresponding to the wheel is excited and opened. Thereby, a part of the brake fluid pressure of the wheel that is about to enter the locked state is absorbed by the first reservoir 8A or the second reservoir 8B, and the brake fluid pressure of the wheel that is about to enter the locked state is reduced. It will be.

  Further, when the brake fluid pressure is kept constant, the inlet valves 6A to 6D are excited and closed, and the outlet valves 9A to 9D are demagnetized and closed, and when the brake fluid pressure is further increased. The inlet valves 6A to 6D may be demagnetized and opened, and the outlet valves 9A to 9D may be demagnetized and closed.

  By controlling the demagnetization / excitation of the inlet valves 6A to 6D and the outlet valves 9A to 9D in this way, braking can be efficiently performed without locking the wheels.

  By the way, during the antilock brake control as described above, the electric motor 11 is rotated, and the first and second pumps 10A and 10B are driven in accordance with the operation of the electric motor 11. Therefore, the first and second pumps are driven. The brake fluid absorbed in the reservoirs 8A and 8B is sucked into the first and second pumps 10A and 10B, and then passes through the first and second dampers 13A and 13B to the first and second output hydraulic pressure paths 3A and 3B. Refluxed. Such recirculation of the brake fluid can prevent an increase in the amount of depression of the brake pedal P due to the absorption of the brake fluid in the first and second reservoirs 8A and 8B. In addition, the pulsation of the discharge pressures of the first and second pumps 10A and 10B is suppressed by the action of the first and second dampers 13A and 13B, and the operation feeling of the brake pedal P is not hindered by the reflux.

  Thus, the first and second pumps functioning as a hydraulic pressure generating source by exciting and opening the suction valves 18A and 18B and operating the electric motor 11 with the cut valves 17A and 17B excited and closed. 10A and 10B suck the brake fluid from the master cylinder M side and discharge the pressurized brake fluid to the first and second hydraulic pressure paths 20A and 20B.

  Pressure sensors 15A and 15B for detecting brake fluid pressure are connected to the left front wheel and right front wheel brakes 2A and 2C.

  In FIG. 2, in the left front wheel brake 2 </ b> A that is a disc brake with a parking brake mechanism, a first friction pad 72 and a second friction pad 73 are arranged opposite to each other of a brake disc 71 that rotates with the wheel. These first and second friction pads 72 and 73 are composed of linings 72a and 73a that can come into contact with the brake disc 71, and back plates 72b and 73b fixed to the back side of the linings 72a and 73a. The back plates 72b and 73b are supported by the bracket 74 fixed to the vehicle body so as to be movable in the axial direction of the brake piston 78. A brake caliper 75 straddling the first and second friction pads 72 and 73 is supported on the bracket 74 so as to be movable in the axial direction of the brake piston 78.

  The brake caliper 75 includes a first sandwiching arm 75a facing the back plate 72b of the first friction pad 72 and a second sandwiching arm 75b facing the back plate 73b of the second friction pad 73. The second sandwiching arms 75 a and 75 b are integrally connected by a bridging portion 75 c that passes through the outer periphery of the brake disc 71. The first pinching arm 75 a is provided with a cylinder hole 76, and a cup-shaped brake piston 78 is slidably fitted into the cylinder hole 76 via a seal member 77. The front end of the brake piston 78 facing the back plate 72b of the first friction pad 72 is connected to the open end of the cylinder hole 76 by a bellows-like dust cover 79, and the brake facing the back of the brake piston 78 A hydraulic chamber 80 is formed in the first clamping arm 75a, and the brake hydraulic chamber 80 is connected to the inlet valve 6A via a port 81 provided in the first clamping arm 75a.

  An adjusting mechanism 82 is provided in the first pinching arm 75a of the brake caliper 75, and this adjusting mechanism 82 is connected to the brake piston 78 so as not to be relatively rotatable and is accommodated in the brake hydraulic pressure chamber 80. An adjusting nut 83, an adjusting bolt 84 whose front end is screwed to the adjusting nut 83, and a rear portion of the brake fluid pressure chamber 80, and capable of moving in the axial direction while preventing rotation around the axis. And a relay piston 85 that is liquid-tightly and slidably fitted to the brake caliper 75, and is integrally and coaxially connected to the rear portion of the adjustment bolt 84 so as to be liquid-tight and slidable to the relay piston 85. And a small piston 86 that is elastically biased in the direction of frictional engagement with the relay piston 85.

  A relay cylinder hole 87 having a diameter smaller than that of the cylinder hole 76 is coaxially provided at an end of the first clip arm 75a of the brake caliper 75 opposite to the brake disc 71, and a rear portion of the stepped relay piston 85 is provided. The front part is inserted into the rear part of the cylinder hole 76 and is slidably fitted into the relay cylinder hole 87 via the seal member 88. Moreover, the brake caliper 75 and the relay piston 85 are fitted with both ends of a regulation pin 89 that has an axis parallel to the cylinder hole 76 and the relay cylinder hole 87 and is disposed at a position offset from the axis of the cylinder hole 76. The As a result, the relay piston 85 is prevented from rotating around an axis that is coaxial with the cylinder hole 76 and the relay cylinder hole 87 and can be moved along the axis to be supported by the brake caliper 75. .

  The relay piston 85 is coaxially provided with a small cylinder hole 91 having a tapered clutch surface 90 at the front end opening. On the other hand, at the rear part of the adjusting bolt 84, a movable clutch body 92 that can be frictionally engaged with the clutch surface 90 and a small piston 86 that fits in the small cylinder hole 91 in a liquid-tight and slidable manner are coaxial. And it is connected continuously.

  A retainer 95 engaged and supported by a clip 94 mounted on the inner surface of the cylinder hole 76 has one end of a clutch spring 93 that exerts a spring force that frictionally engages the movable clutch body 92 with the clutch surface 90 of the relay piston 85. The other end of the clutch spring 93 comes into contact with the movable clutch body 92 via a ball bearing 96.

  The adjustment nut 83 and the adjustment bolt 84 are engaged with each other by a quick screw 97 having a plurality of threads and a groove having a coarse pitch. One end of an over-adjustment prevention spring 98 that exerts a spring force that urges the adjustment nut 83 toward the brake piston 78 is brought into contact with the adjustment nut 83 and is engaged and supported by a clip 99 mounted on the inner surface of the brake piston 78. The other end of the over-adjustment prevention spring 98 is brought into contact with and supported by the retainer 100.

  The adjustment nut 83 and the brake piston 78 cannot be rotated relative to each other due to the concave-convex engagement of the contact portions, and the back plate 72b of the first friction pad 72 and the brake piston 78 cannot be rotated relative to each other due to the concave-convex engagement. It is.

  In such an adjustment mechanism 82, when hydraulic pressure is supplied to the brake hydraulic pressure chamber 80 during normal braking, the brake piston 78 that receives the hydraulic pressure elastically deforms the seal member 77 in the cylinder hole 76 in FIG. When the first friction pad 72 is pressed against one side of the brake disk 71, the brake caliper 75 moves to the right in the direction opposite to the moving direction of the brake piston 78, and the second pinching arm 75b moves. The second friction pad 73 is pressed against the other side of the brake disc 71. As a result, the first and second friction pads 72 and 73 come into contact with both surfaces of the brake disc 71 with an equal surface pressure, and a braking force for braking the wheel is generated.

  During the braking, the hydraulic pressure supplied to the brake hydraulic pressure chamber 80 does not cause the adjustment nut 83 to generate an axial load, but the movable clutch body 92 integrated with the adjustment bolt 84 meshing with the adjustment nut 83. In this case, a rightward load having a magnitude obtained by multiplying the cross-sectional area of the small piston 86 by the hydraulic pressure is generated, and a frictional engagement force corresponding to the load acts between the movable clutch body 92 and the clutch surface 90 of the relay piston 85. To do.

  Incidentally, since the hydraulic pressure acting on the brake hydraulic pressure chamber 80 during normal braking is relatively low, the frictional engagement force acting between the movable clutch body 92 and the relay piston 85 is also relatively small. Therefore, when the brake piston 78 moves forward with the progress of wear of the linings 72 a and 73 a of the first and second friction pads 72 and 73, the adjustment nut 83 moves forward together with the brake piston 78 by the elastic force of the over-adjustment prevention spring 98. Then, the movable clutch body 92 integrated with the adjustment bolt 84 meshing with the adjustment nut 83 is separated from the clutch surface 90 of the relay piston 85 against the hydraulic pressure acting on the brake hydraulic pressure chamber 80 and the elastic force of the clutch spring 93. It is.

  When the movable clutch body 92 is separated from the clutch surface 90 of the relay piston 85, the adjustment bolt 84 urged to the right by the hydraulic pressure acting on the movable clutch body 92 and the elastic force of the clutch spring 93 becomes an unrotatable adjustment nut. While moving in the fast screw 97 relative to 83, the movable clutch body 92 moves to the right while being relatively rotated, and the clutch surface 90 of the relay piston 85 is engaged again. At this time, the movable clutch body 92 can be smoothly rotated by the action of the ball bearing 96 arranged between the clutch spring 93.

  In this way, as the wear of the linings 72a and 73a in the first and second friction pads 72 and 73 progresses, the adjustment nut 83 moves relative to the left side with respect to the adjustment bolt 84 so as to compensate for the amount of wear. Therefore, the clearance between the linings 72a and 73a of the first and second friction pads 72 and 73 and the brake disk 71 during non-braking can be automatically maintained constant.

  When the hydraulic pressure acting on the brake hydraulic pressure chamber 80 is reduced to release the brake state, the brake piston 78 moves backward due to the deformation restoring force of the seal member 77, but the reverse force is transmitted via the adjustment nut 83 and the adjustment bolt 84. Since the movable clutch body 92 is engaged with the clutch surface 90 of the relay piston 85, the relative rotation of the adjustment bolt 84 with respect to the adjustment nut 83 is restricted. Therefore, the brake piston 78 can only move backward by a stroke corresponding to the backlash between the adjusting nut 83 and the adjusting bolt 84, and the backlash is between the first and second friction pads 72 and 73 and the brake disk 71. Proper clearance of minutes is given.

  When strong braking is performed, the automatic adjustment is performed until the hydraulic pressure in the brake hydraulic pressure chamber 80 rises to a predetermined value that causes the brake caliper 75 to deform, and the hydraulic pressure reaches the predetermined value. When exceeding, the movable clutch body 92 is strongly pressed against the clutch surface 90 of the relay piston 85 by hydraulic pressure, so that the movable clutch body 92 and the relay piston 85 are coupled so as not to be relatively rotatable. As a result, the adjustment bolt 84 is restrained to be non-rotatable and the adjustment nut 83 that is originally non-rotatable remains on the adjustment bolt 84. Therefore, when the brake piston 78 further moves forward due to elastic deformation of the brake caliper 75 due to hydraulic pressure, While compressing the adjustment prevention spring 98, only the brake piston 78 moves forward leaving the adjustment nut 83. In this way, over-adjustment between the adjusting nut 83 and the adjusting bolt 84 when strong braking is performed is prevented.

  Referring also to FIG. 3, a casing 23 that extends to the opposite side of the brake disc 71 is connected to the first pinching arm 75 a of the brake caliper 75, and a parking piston that contacts the relay piston 85 from the rear side. 24 is slidably fitted to the casing 23.

  The casing 23 forms a sliding hole 26 coaxial with the cylinder hole 76 of the brake caliper 75, and a parking brake state can be obtained by a forward operation according to the action of the control fluid pressure for parking on the back surface. The parking piston 24 is slidably fitted into the sliding hole 26 so as to contact the relay piston 85 from the rear, and the parking piston 24 is mechanically locked in the forward position. A lock mechanism 25 that automatically locks in response to the forward operation and unlocks in response to the action of the parking release control hydraulic pressure is provided in the casing 23 on the rear side of the parking piston 24.

  The sliding hole 26 has a larger diameter than the relay cylinder hole 87 and a front sliding hole part 26a coaxially connected to the rear end of the relay cylinder hole 87, and a smaller diameter than the front sliding hole part 26a. The rear sliding hole 26a is coaxially connected to the rear end of the front sliding hole 26a and has a rear sliding hole 26b. The inner surface of the casing 23 is formed between the front sliding hole 26a and the rear sliding hole 26b. Is formed with an annular step 26c facing forward, and the rear end of the sliding hole 26b is closed by the rear end wall 23a of the casing 23.

  The parking piston 24 includes a large diameter portion 24a formed between a large diameter portion 24a slidably fitted in the front sliding hole portion 26a and an annular step portion 24c facing rearward. 24a has a small diameter portion 24b that is coaxially connected to the rear portion of the rear portion 24a and is slidably fitted in the rear sliding hole 26b. The pressing rod 24d is integrally and coaxially connected.

  Between the step part 24c of the parking piston 24 and the step part 26c of the casing 23, between the casing 23 and the parking piston 24, an annular parking control liquid for applying the parking control hydraulic pressure to the parking piston 24 from the back side. A pressure chamber 27 is formed, and annular sealing members 28 and 29 for sealing the parking control hydraulic pressure chamber 27 from both sides are mounted on the outer surfaces of the large diameter portion 24 a and the small diameter portion 24 b of the parking piston 24. In addition, the pressure receiving area of the parking piston 24 facing the parking control hydraulic pressure chamber 27 is set larger than the pressure receiving area of the small piston 86 facing the brake hydraulic pressure chamber 80.

  The lock mechanism 25 includes a lock piston 30 disposed behind the parking piston 24 so as to apply a forward biasing force to the parking piston 24 when the parking piston 24 moves forward.

  The lock piston 30 has an axis orthogonal to the axis of the parking piston 24, and both ends of the lock piston 30 are slid and supported by the casing 23. That is, the lock piston 30 is formed with a small diameter shaft 30a on one end side that is slid and supported by the casing 23, and a large diameter on the other end side that is slid and supported on the casing 23 while having a larger diameter than the small diameter shaft portion 30a. A diameter cylinder part 30b and a taper part 30c connecting the small diameter shaft part 30a and the large diameter cylinder part 30b are provided integrally and coaxially so as to cross the rear sliding hole 26b behind the sliding hole 26 behind the parking piston 24. Placed in.

  The casing 23 is provided with a bottomed cylinder hole 32 in which a small diameter shaft portion 30a of the lock piston 30 is slidably fitted and a control hydraulic pressure chamber 31 for parking release is formed between the casing 23 and the small diameter shaft portion 30a. An annular seal member 33 slidably contacting the inner surface of the cylinder hole 32 is mounted on the outer surface of the small diameter shaft portion 30a.

  Further, a support hole 33 coaxial with the cylinder hole 32 is provided in the casing 23 so as to slidably fit the large-diameter cylindrical portion 30b, and the outer end opening of the support hole 33 is formed in the casing. It is closed with a lid member 34 screwed to 23. In addition, a spring 35 that is contracted between the lid member 34 and the lock piston 30 is accommodated in the support hole 33, and the lock piston 30 has one end in the axial direction, that is, the spring force exerted by the spring 35. The parking release control hydraulic pressure chamber 31 is energized to reduce the volume.

  The lock mechanism 25 also includes a sphere 36 interposed between the tapered portion 30 c of the lock piston 30 and the rear end of the small diameter portion 24 b of the parking piston 24, and the sphere 36 includes the parking piston 24. Are accommodated in a tapered receiving recess 37 provided at the center of the rear end of the small-diameter portion 24b so as to be capable of rolling, and in contact with the tapered portion 30c.

According to such a lock mechanism 25, the lock piston 25 is elastically biased toward the one side in the axial direction by the spring 35, and the tapered portion 30 c of the lock piston 30 is connected to the rear end of the parking piston 24 via the sphere 36. Since the springs 35 are connected, the spring urging force toward the front side is applied to the parking piston 24 via the tapered portion 30c and the sphere 36. Thus, the spring load of the spring 35 is set so that the spring biasing force acting on the parking piston 24 toward the front side is smaller than the spring load of the clutch spring 93 in the adjustment mechanism 82.

  The parking control fluid pressure acting on the parking control fluid pressure chamber 27 and the parking release control fluid pressure acting on the parking release control fluid chamber 31 function as a fluid pressure generation source when driven by the electric motor 11. The hydraulic pressure discharged from the first pump 10A is controlled by the hydraulic pressure control means 40A. The hydraulic pressure control means 40A is provided in the casing 23 through the parking control hydraulic pressure chamber 27. The first normally closed solenoid valve 41 interposed between the hydraulic pressure path 43 and the inlet valve 6A, the hydraulic pressure path 44 provided in the casing 23 through the control hydraulic pressure chamber 31 for parking release, and the inlet valve 6A. And a second normally closed electromagnetic valve 42 interposed therebetween.

When the parking brake state is obtained, the first pump 10A is driven by the electric motor 11, the cut valve 17A is excited and closed, the suction valve 18A is excited and opened, and the hydraulic pressure control means 40A is first closed normally. The electromagnetic valve 41 is excited and opened. Thus, the brake fluid pressure is applied to the brake fluid pressure chamber 80, the parking control fluid pressure is applied to the parking control fluid pressure chamber 27, and the second normally closed electromagnetic valve 42 is excited and opened to perform parking. By applying hydraulic pressure to the release control hydraulic pressure chamber 31, the brake piston 78 and the parking piston 24 are advanced while suppressing the movement of the lock piston 30 to one side in the axial direction by the spring 35. Next, the first electromagnetic normally closed solenoid valve 41 is demagnetized and closed, the drive of the first pump 10A by the electric motor 11 is stopped, the cut valve 17A is demagnetized and opened, and the suction valve 18A is demagnetized and closed. When the valve is operated, the hydraulic pressure of the parking release control hydraulic pressure chamber 31 is released, and as shown in FIG. The lock mechanism 25 is locked in accordance with the movement of 30 in one axial direction. However, when the movement of the lock piston 25 in one axial direction is completed (that is, when the lock piston 25 is held at the lock operation position shown in FIG. 4) , the first normally closed solenoid valve 41 is temporarily excited. Then, the valve is opened to release the residual pressure in the parking control hydraulic chamber 27.

  Thus, when the parking piston 24 is locked by the forward operation, the relay piston 85 is advanced by the pressing rod 24d provided at the front end of the parking piston 24, and the movement of the relay piston 85 is adjusted by the movable clutch body 92. The brake piston 78 is moved forward via the bolt 84 and the adjusting nut 83, and the linings 72a and 73a of the first and second friction pads 72 and 73 are pressed against both surfaces of the brake disc 71 in the same manner as in normal braking. By generating it, the parking brake state can be obtained.

  In the process of obtaining the parking brake state, the relay piston 85 and the movable clutch body 92 are frictionally engaged with each other by the pressing force of the parking piston 24 so that they cannot be rotated relative to each other, so that the relative rotation of the adjusting bolt 84 and the adjusting nut 83 is restricted. Therefore, when the left front wheel brake 2A functions as a parking brake, the automatic adjustment by the adjustment mechanism 82 is not performed.

  Further, when the parking brake state is obtained during the normal brake operation, when the detected value of the pressure sensor 15A is sufficiently high, the master cylinder M is used as a hydraulic pressure generation source, and the first pump 10A is not driven by the electric motor 11. Moreover, it is only necessary to operate the hydraulic pressure control means 40A with the cut valve 17A demagnetized and opened and the suction valve 18A demagnetized and closed. When the detected value of the pressure sensor 15A is low, the electric motor 11 While the pump 10A is being driven, the cut valve 17A is excited and closed, the suction valve 18A is excited and opened, and the hydraulic pressure control means 40A is operated, and further, the detection value of the pressure sensor 15A is activated. When the first valve 10A is driven by the electric motor 11, the cut valve 17A is excited and closed. Exciting the monitor suction valve 18A, opens, it may be allowed to operate the hydraulic control means 40A.

  The right front wheel brake 2C is configured in the same manner as the left front wheel brake 2A described above. When the parking brake state of the right front wheel brake 2C is obtained, the suction valve 18B is excited and opened, and a cut valve is provided. By operating the electric motor 11 with 17B excited and closed, the second pump 10B functions as a hydraulic pressure generation source, and the operation of the hydraulic pressure control means 40B may be controlled.

Next, the operation of this embodiment will be described. When the parking control hydraulic pressure is applied to the back side of the parking piston 24, the parking piston 24 moves forward and the lock piston 30 of the lock mechanism 25 moves to the lock operation position. Since the forward movement position of the parking piston 24 is mechanically locked, the parking brake state can be automatically obtained. When the parking brake state is released, the parking release control hydraulic pressure is set to the lock mechanism 25 . may be Seshimere acting on the lock piston 30, it is possible to obtain a parking brake state automatically by a simple structure without power consumption in the parking brake state.

In addition, the lock mechanism 25 includes a lock piston 30 that is disposed behind the parking piston 24 and is slidable in a direction orthogonal to the axis of the parking piston 24 and is fitted and supported at both ends in the axial direction of the casing 23. The lock piston 30 is urged to one side in the axial direction of the lock piston 30 by a spring 35. When the parking piston 24 moves forward, a biasing force acting forward is applied to the parking piston 24. In this way, the parking piston 24 is moved and held at the lock operating position where the parking piston 24 is locked. At the lock operating position, the reaction force acting on the axial intermediate portion of the lock piston 30 from the rear end of the parking piston 24 is applied. Both ends of the lock piston 30 are supported by the casing 23 so as to be dispersed at both axial ends. It can be.

Therefore, it is possible to reduce the weight by avoiding an increase in the thickness for increasing the strength of the portion of the casing 23 that supports the lock piston 30, and the portion of the casing 23 that houses the lock piston 30 in the parking piston axial direction . It is possible to shorten the axial direction of the casing by shortening the length relatively.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

It is a hydraulic circuit diagram of the brake device for vehicles. It is a longitudinal cross-sectional view of the disc brake at the time of a non-parking brake. FIG. 3 is an enlarged view of a main part of FIG. 2. It is sectional drawing corresponding to FIG. 3 in a parking brake state.

Explanation of symbols

10A, 10B: Pump 23 as a fluid pressure source ... Casing 24 ... Parking piston 25 ... Lock mechanism 30 ... Lock piston
30c ・ ・ Taper part
31 ... Control hydraulic chambers 40A, 40B for releasing parking ... Fluid pressure control means M ... Master cylinder as fluid pressure source

Claims (2)

A parking piston (24) slidably fitted to the casing (23) so as to be able to obtain a parking brake state by a forward operation according to the action of the control fluid pressure for parking on the back side;
In order to mechanically lock the parking piston (24) in the forward movement position, the parking piston (24) is automatically locked according to the forward movement of the parking piston (24) and unlocked according to the action of the parking release control hydraulic pressure. as the lock is provided before Symbol casing (23) inside in mechanism (25),
Hydraulic pressure source (10A, 10B, M);
Fluid pressure control means (40A, 40B) capable of obtaining the parking control fluid pressure and the parking release control fluid pressure by controlling the fluid pressure generated by the fluid pressure source (10A, 10B, M). Including
The lock mechanism (25) is disposed behind the parking piston (24), engages with the rear end of the parking piston (24), and is slidable in a direction perpendicular to the axis of the parking piston (24). As provided with a lock piston (30) fitted and supported at both ends in the axial direction to the casing (23),
The lock piston (30) is urged toward one side in the axial direction of the lock piston (30), and is attached to the parking piston (24) forward at least when the parking piston (24) moves forward. The parking piston (24) can be held in a locking position to lock the parking piston (24) so as to exert a force . In the locking position, the axial direction of the locking piston (30) from the rear end of the parking piston (24). A parking brake device characterized in that a reaction force acting on an intermediate portion is supported at both ends by the casing (23) . One end portion in the axial direction of the lock piston (30) is formed to have a smaller diameter than the other end portion, and a parking release control hydraulic pressure chamber (31) into which the parking release control hydraulic pressure can be introduced at the one end portion. The parking brake device according to claim 1, wherein the parking brake device faces the one end and the other end of the lock piston (30) by a tapered portion (30c).

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