JP2005180500A - Parking brake device - Google Patents

Abstract

In a parking brake device, a service brake and a parking brake have two operation systems, but a service brake and a parking brake transmission system are partially shared to avoid an increase in system size and cost. To do.
Wheel brakes (2A, 2C) are configured to switch between a parking brake state and a parking brake release state in accordance with the action of the control fluid pressure for parking and parking release, and the output hydraulic pressure of a master cylinder (M) is adjusted to the wheel brake (2A). The parking cylinder 4 that divides the hydraulic pressure paths 3A, 3B into the upstream hydraulic pressure paths 3Au, 3Bu and the downstream hydraulic pressure paths 3Ad, 3Bd is connected to the hydraulic pressure paths 3A, 3B leading to the 2C side. A parking cylinder 4 is provided which can output hydraulic pressure to the downstream hydraulic pressure paths 3Ad and 3Bd while blocking between the upstream and downstream hydraulic pressure paths 3Au and 3Bu; 3Ad and 3Bd according to the operation.
[Selection] Figure 1

Description

  The present invention relates to a parking brake device that obtains a parking brake state by locking a wheel brake in a brake operating state.

A lever brake or pedal operated by a vehicle driver is mechanically transmitted to a wheel brake by a wire to obtain a parking brake state (for example, see Patent Document 1), or a pump driven by an electric motor There is one in which the wheel brake is automatically parked using the pressure of the pressure and the operation state is mechanically locked (see, for example, Patent Document 2).
No. 6-50677 Japanese Patent Laid-Open No. 11-342837

  By the way, in a vehicle that can obtain the parking brake state, two operation systems are required for the service brake and the parking brake. However, in the one disclosed in Patent Document 1, the service brake hydraulic system is In addition, a parking brake operating force transmission system using a wire for obtaining a parking brake state is required, and piping and routing are complicated, resulting in an increase in cost. Further, the one disclosed in Patent Document 2 requires an electric motor and a pump for obtaining a parking brake state separately from the service brake hydraulic system, which also causes an increase in system size and cost.

  The present invention has been made in view of such circumstances. Although the service brake and the parking brake have two operation systems, the service brake and the parking brake transmission system are partially shared, An object of the present invention is to provide a parking brake device that can avoid an increase in size and cost.

  In order to achieve the above object, the present invention provides a master cylinder that generates a hydraulic pressure corresponding to an operation amount of a brake operating member, a wheel brake that operates by a hydraulic pressure generated in the master cylinder, and a rear surface. A parking piston that is slidably fitted to the casing so that the parking brake state of the wheel brake can be obtained by a forward operation according to the action of the control fluid pressure for parking, and mechanically moves the parking piston at the forward position. The parking piston automatically locks in response to the forward movement of the parking piston and unlocks in response to the operation of the parking release control hydraulic pressure so as to be behind the parking piston in the casing. The lock mechanism provided and the output hydraulic pressure of the master cylinder are guided to the wheel brake side. The hydraulic pressure path is divided into an upstream hydraulic pressure path on the master cylinder side and a downstream hydraulic pressure path on the wheel brake side, and is provided in the middle of the hydraulic pressure path and in response to an operation of the parking operation member. A parking cylinder capable of outputting a hydraulic pressure corresponding to an operation amount of the parking operation member to the downstream hydraulic pressure path while blocking between the upstream hydraulic pressure path and the downstream hydraulic pressure path, and the downstream hydraulic pressure And a hydraulic pressure control means capable of obtaining the parking control hydraulic pressure and the parking release control hydraulic pressure by controlling the hydraulic pressure of the road.

  According to the present invention, when the parking control hydraulic pressure is applied to the back surface of the parking piston, the parking piston moves forward, and the lock mechanism mechanically locks the advance position of the parking piston. 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 state is automatically set with a simple structure that does not involve power consumption. Can be obtained.

  Moreover, a parking cylinder that divides the hydraulic pressure path into an upstream hydraulic pressure path on the master cylinder side and a downstream hydraulic pressure path on the wheel brake side in the middle of the hydraulic pressure path that guides the output hydraulic pressure of the master cylinder to the wheel brake side. The parking cylinder is provided for a parking brake according to the operation amount of the parking operation member while blocking between the upstream hydraulic pressure passage and the downstream hydraulic pressure passage according to the operation of the parking operation member. The hydraulic pressure can be output to the downstream hydraulic pressure path, and the control hydraulic pressure for parking and the control hydraulic pressure for parking release are obtained by controlling the hydraulic pressure in the downstream hydraulic pressure path with the hydraulic pressure control means. Can do.

  That is, the brake hydraulic pressure output from the master cylinder is applied to the wheel brake by operating the brake operating member during service braking, and the parking brake is operated by the hydraulic pressure output from the parking cylinder by operating the parking operating member during parking brake. It is possible to obtain the state and cancel the parking brake state, and although it has two operation systems, the service side and the parking brake are partially shared by the downstream hydraulic pressure path as the transmission system and the electric motor and pump Therefore, it is possible to avoid an increase in the size of the system and an increase in cost.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 4 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, a tandem master cylinder M includes first and second output ports 1A and 1B that generate brake fluid pressure in accordance with a pedaling force applied to a brake pedal P as a brake operation member by a vehicle driver. The first output port 1A has a first output hydraulic pressure passage 3A for guiding brake hydraulic pressure to the left front wheel brake 2A, which is a disc brake with a parking brake mechanism, and to the right rear wheel brake 2B, which is a disc brake. And the second output port 1B is a second output hydraulic pressure for guiding the brake hydraulic pressure to the right front wheel brake 2C that is a disc brake with a parking brake mechanism and the left rear wheel brake 2D that is a disc brake. Connected to path 3B.

  The first and second output hydraulic pressure paths 3A, 3B are respectively connected to the upstream hydraulic pressure paths 3Au, 3Bu on the master cylinder M side by the parking cylinder 4 interposed in the middle of the hydraulic pressure paths 3A, 3B. The wheel brakes 2A and 2B are divided into downstream hydraulic pressure passages 3Ad and 3Bd on the 2C and 2D sides. Moreover, the parking cylinder 4 does not block between the upstream hydraulic pressure passages 3Au and 3Bu and the downstream hydraulic pressure passages 3Ad and 3Bd except when the vehicle driver operates to obtain a parking brake state. At the time of service braking, the upstream hydraulic pressure paths 3Au and 3Bu and the downstream hydraulic pressure paths 3Ad and 3Bd are in communication with each other.

  The downstream hydraulic pressure path 3Ad of the first output hydraulic pressure path 3A is connected to the first hydraulic pressure path 20A via the cut valve 17A, which is a normally open solenoid valve, and the downstream side hydraulic pressure path 3B is downstream of the second output hydraulic pressure path 3B. The pressure path 3Bd is connected to the second hydraulic pressure path 20B via a cut valve 17B that is a normally open electromagnetic valve.

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

  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 upstream hydraulic pressure passages 3Au and 3Bu of the first and second output hydraulic pressure passages 3A and 3B are connected to the first and second pumps 10A and 10B via suction valves 18A and 18B, which are normally closed solenoid valves. Connected between the one-way valves 19A and 19B, 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. Is done.

  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. For example, 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, then passes through the first and second dampers 13A and 13B, and flows through the first and second output hydraulic pressure paths 3A and 3B. It returns to the downstream hydraulic pressure paths 3Ad, 3Bd. 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 10A and 10B are operated as master cylinders by energizing and opening the suction valves 18A and 18B and operating the electric motor 11 with the cut valves 17A and 17B energized and closed. The brake fluid sucked and pressurized from the M side is discharged 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.

  By the way, the parking cylinder 4 forms a cylinder body 22 by forming a cylinder body 22 having a closed front end and a front output hydraulic pressure chamber 23 communicating with the downstream hydraulic pressure path 3Ad between the front end closed portion of the cylinder body 22. A slidably fitted front piston 25 and a rear output hydraulic pressure chamber 24 communicating with the downstream hydraulic pressure passage 3Bd are formed between the front piston 25 and slidably fitted to the cylinder body 22. A rear piston 26, a front end closing portion of the cylinder body 22 and a front return spring 27 interposed between the front pistons 25, and a rear return spring 28 interposed between the front and rear pistons 25, 26. With.

  A parking pedal 29 that is a parking operation member operated by a vehicle driver is connected to the rear piston 26. Moreover, the upstream hydraulic pressure passages 3Au and 3Bu of the first and second output side hydraulic pressure passages 3A and 3B are arranged so that the front and rear pistons 25 and 26 are in the retreat limit when the parking pedal 29 is not operated. Although connected to the rear output hydraulic chambers 23 and 24, when the front and rear pistons 25 and 26 move forward from the retreat limit according to the operation of the parking pedal 29, they are cut off from the front and rear output hydraulic chambers 23 and 24. In this way, the cylinder body 22 is connected.

  According to such a parking cylinder 4, when the parking pedal 29 is operated, in the first and second output side hydraulic pressure passages 3A and 3B, between the upstream side hydraulic pressure passages 3Au and 3Bu and the downstream side hydraulic pressure passages 3Ad and 3Bd. And the parking brake hydraulic pressure corresponding to the amount of operation of the parking pedal 29 is output from the front and rear output hydraulic pressure chambers 23, 24 to the downstream hydraulic pressure paths 3Ad, 3Bd.

  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 be brought into contact with the brake disc 71, and back plates 72b and 73b fixed to the back surfaces of the linings 72a and 73a. The back plates 72 b and 73 b are supported by a 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 102 extending on the opposite side to the brake disc 71 is integrally connected to the first sandwiching arm 75 a of the brake caliper 75 and abuts against the relay piston 85 from the rear side. The parking piston 103 is slidably fitted to the casing 102.

  The casing 102 forms a sliding hole 101 that is 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 103 is slidably fitted into the sliding hole 101 so as to contact the relay piston 85 from the rear, and the parking piston 103 is mechanically locked in the forward position. A lock mechanism 105 that automatically locks in accordance with the forward operation and unlocks in response to the action of the parking release control hydraulic pressure is provided in the casing 102 on the rear side of the parking piston 103.

  The sliding hole 101 has a diameter larger than that of the relay cylinder hole 87 and is connected to the rear end of the relay cylinder hole 87 coaxially with the parking piston front sliding hole 101a and the parking piston front sliding hole 101a. The parking piston rear sliding hole portion 101b as a large diameter hole portion that is formed in a small diameter and is coaxially connected to the rear end of the parking piston front sliding hole portion 101a, and smaller in diameter than the parking piston rear sliding hole portion 101b. A lock piston front sliding hole portion 101c as a small diameter hole portion that is coaxially connected to the rear end of the parking piston rear sliding hole portion 101b and has a larger diameter than the lock piston front sliding hole portion 101c. The lock piston front sliding hole 101c has a lock piston rear sliding hole 101d coaxially connected to the rear end of the lock piston front sliding hole 101c. The rear end of 1d is closed at the rear end wall 102a of the casing 102.

  An annular step 101e facing forward is formed on the inner surface of the casing 102 between the parking piston front sliding hole 101a and the parking piston rear sliding hole 101b, and the parking piston rear sliding hole 101 and front of the lock piston are formed. An annular locking step 101f facing forward is formed on the inner surface of the casing 102 between the inner sliding holes 101c, and the casing is further formed between the locking piston front sliding hole 101c and the locking piston rear sliding hole 101d. An annular step portion 101g facing rearward is formed on the inner surface of 102.

  The parking piston 103 is formed by forming a large-diameter portion 103a slidably fitted in the parking piston front sliding hole portion 101a and an annular step portion 103c facing the rear, and the large-diameter portion 103a. It has a small diameter portion 103b that is coaxially connected to the rear portion of the diameter portion 103a and is slidably fitted in the rear sliding hole 101b of the parking piston. A pressing rod 103d for pressing from the side is integrally and coaxially connected.

  Between the step part 103c of the parking piston 103 and the step part 101e of the casing 102, between the casing 102 and the parking piston 103, an annular parking control liquid for applying the parking control hydraulic pressure to the parking piston 103 from the back side. A pressure chamber 106 is formed, and annular sealing members 107 and 108 for sealing the parking control hydraulic pressure chamber 106 from both sides are mounted on the outer surfaces of the large diameter portion 103 a and the small diameter portion 103 b of the parking piston 103. In addition, the pressure receiving area of the parking piston 103 facing the parking control hydraulic pressure chamber 106 is set larger than the pressure receiving area of the small piston 86 facing the brake hydraulic pressure chamber 80.

  The locking mechanism 105 is slidably fitted to the casing 102 on the rear side of the parking piston 103 so that a forward biasing force is applied when the parking piston 103 moves forward, and the parking release control liquid A lock piston 104 capable of applying pressure toward the rear, a cylindrical holding cylinder 51 integrally and coaxially connected to a rear portion of the parking piston 103, and a plurality of circumferential positions of the holding cylinder 51 Are held so as to be movable in the direction along the radial direction of the holding cylinder, and the respective spheres 52, 52... Are in contact with the respective spheres 52, 52. Is integrally connected to the front end of the lock piston 104 so as to be inserted into the holding cylinder 51 so as to be movable in the axial direction so as to be sandwiched between the inner surface of the casing 102 and the casing 102. And a insertion axis 53 that.

  The lock piston 104 is formed with a small diameter portion 104a formed between a small diameter portion 104a slidably fitted into the lock piston front sliding hole portion 101c and a rear portion of the small diameter portion 104a. A large-diameter portion 104b that is coaxially connected to the rear portion of the portion 104a and that is slidably fitted into the rear sliding hole portion 101d of the lock piston is integrally provided.

  An annular parking release control hydraulic pressure chamber 109 is formed between the lock piston 104 and the casing 102 between the step 104c of the lock piston 104 and the step 101g of the casing 102, and the rear end wall 102a of the casing 102 and the lock piston. A spring chamber 110 is formed between 104, and an open chamber 111 opened to the outside is formed in the casing 102 between the parking piston 103 and the lock piston 104.

  Thus, on the outer surface of the small diameter portion 104 a of the lock piston 104, an annular seal member 112 that seals between the parking release control hydraulic pressure chamber 109 and the open chamber 111 is mounted, and the outer surface of the large diameter portion 104 b of the lock piston 104. Is attached with an annular seal member 113 for sealing between the parking release control hydraulic pressure chamber 109 and the spring chamber 110.

  A spring 114 is contracted between the rear end wall 102a and the lock piston 104, and the lock piston 24 is elastically biased toward the front side by the spring force of the spring 114. Moreover, the spring load of the spring 114 is set smaller than the spring load of the clutch spring 93 in the adjustment mechanism 82.

  Holding holes 54, 54... Are provided at a plurality of positions spaced in the circumferential direction of the holding cylinder 51, and the respective spheres 52, 52... Are inserted and held in the holding holes 54, 54.

  Further, at least a portion of the outer peripheral surface of the insertion shaft 53 that can contact the spheres 52, 52... Moves the spheres 52, 52, in the radial direction of the holding cylinder 51 when the parking piston 103 is in the retreat limit. When the lock piston 104 moves forward in accordance with advancement from the retreat limit of the parking piston 103, the spherical bodies 52, 52... Are moved outward along the radial direction of the holding cylinder 51. A tapered surface 53a having a smaller diameter toward the front side is formed so as to be pushed upward.

  In the parking piston 103 and the lock mechanism 105 as described above, when the parking piston 103 moves forward, the lock piston 104 moves forward as shown in FIG. 4, thereby tapering the outer periphery of the insertion shaft 53 at the front end of the lock piston 104. The spheres 52, 52... Are pushed up by the surface 53a, and the spheres 52, 52... Are sandwiched between the parking piston rear sliding hole portion 101b and the tapered surface 53a in the inner surface of the casing 102. At this time, the force that the parking piston 103 tries to retreat backward acts on the tapered surface 53a through each of the spheres 52, 52..., And acts on the lock piston 104 toward the rear in the axial direction. Since the component force is suppressed to a small value, the parking brake state can be obtained by preventing the retraction of the parking piston 103 by the spring force of the spring 114 that urges the lock piston 104 in the forward direction. Even if the front-rear direction position of the parking piston 103 changes in the brake state, the locked state can be reliably maintained in response to the change in position.

  Further, the parking brake state can be released by causing the control fluid pressure for parking release to act on the lock piston 104 to retract the lock piston 104.

  In addition, the parking formed between the parking piston 103 and the lock piston 104 on the inner surface of the casing 102 is larger in diameter than the holding cylinder 51 so that the spheres 52, 52. A piston rear sliding hole 101b and a lock piston front part that is formed with a smaller diameter than the parking piston rear sliding hole 101b so that the holding cylinder 51 can be inserted, and is arranged behind the parking piston rear sliding hole 101b. Since the sliding hole portion 101c and the annular locking step portion 101f facing forward are formed between the parking piston rear portion sliding hole portion 101b and the lock piston front portion sliding hole portion 101c, the parking piston is operated in the parking brake state. Even if an excessive load is applied to the rear 103, the locking step 101 Each sphere 52, 52 is able to prevent the retraction of the parking piston 103 by abutment, it is possible to prevent the parking brake state from being released undesirably.

  In the parking brake state, since the parking piston 103 is mechanically connected to the brake piston 78 via the adjusting mechanism 82, a reliable parking brake state is maintained regardless of expansion / contraction due to a change in the temperature of the brake fluid. Can be maintained.

  The parking release control hydraulic pressure chamber 109 and the brake hydraulic pressure chamber 80 are in communication with each other via a communication passage 115 (see FIG. 2). The brake hydraulic pressure chamber 80 is a control valve 66A as hydraulic pressure control means. The control valve 66A is, for example, a normally closed electromagnetic valve.

  When the parking brake state is obtained, the parking cylinder 29 is operated to operate the parking cylinder between the upstream hydraulic pressure paths 3Au and 3Bu and the downstream hydraulic pressure paths 3Ad and 3Bd of the first and second output hydraulic pressure paths 3A and 3B. 4, the hydraulic pressure for parking brake corresponding to the operation amount of the parking pedal 29 is output from the front and rear output hydraulic pressure chambers 23 and 24 of the parking cylinder 4 to the downstream hydraulic pressure paths 3Ad and 3Bd. The control valve 66A is excited and opened in a state where the cut valve 17A is demagnetized and opened and the suction valve 18A is demagnetized and closed. As a result, the hydraulic pressure from the parking cylinder 4 is applied to the brake hydraulic pressure chamber 80, the parking control hydraulic pressure is applied to the parking control hydraulic pressure chamber 106, and the hydraulic pressure is applied to the parking release control hydraulic pressure chamber 109. As a result, the brake piston 78 and the parking piston 103 are moved forward while suppressing the forward movement of the lock piston 104. Next, the parking pedal 29 is returned, and the control valve 66A is demagnetized and returned to the closed state. Then, the hydraulic pressure in the parking release control hydraulic pressure chamber 109 is released, the lock piston 104 is moved forward by the spring force of the spring 114, and the lock mechanism 105 is locked according to the advance of the parking piston 103 and the lock piston 104.

  When the parking piston 103 is thus locked by its forward operation, the relay piston 85 is advanced by the pressing rod 103d of the parking piston 103, and the movement of the relay piston 85 is caused by the movable clutch body 92, the adjusting bolt 84, and The brake piston 78 is advanced via 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 to generate a braking force. Thus, 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 103 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.

  When the parking brake state is obtained during normal brake operation, the control valve 66A is demagnetized and opened while the suction valve 18A is demagnetized and closed when the detection value of the pressure sensor 15A is sufficiently high. When the detection value of the pressure sensor 15A is low, the cut valve 17A is excited and closed while the first pump 10A is driven by the electric motor 11, and the suction valve 18A is excited. The control valve 66A may be excited and opened, and the cut valve 17A is excited and closed while the first motor 10A is driven by the electric motor 11 regardless of the detection value of the pressure sensor 15A. At the same time, the suction valve 18A may be excited and opened, and the control valve 66A may be excited and opened.

  When releasing the parking brake state, the parking pedal 29 is operated to park the upstream hydraulic pressure paths 3Au, 3Bu and the downstream hydraulic pressure paths 3Ad, 3Bd of the first and second output hydraulic pressure paths 3A, 3B. The parking brake hydraulic pressure corresponding to the operation amount of the parking pedal 29 is output from the front and rear output hydraulic pressure chambers 23 and 24 of the parking cylinder 4 to the downstream hydraulic pressure passages 3Ad and 3Bd while being cut off by the cylinder 4 and cut. The control valve 66A is excited and opened while the valve 17A is demagnetized and opened, and the suction valve 18A is demagnetized and closed. As a result, the hydraulic pressures in the brake hydraulic pressure chamber 80, the parking control hydraulic pressure chamber 106, and the parking release control hydraulic pressure chamber 109 increase simultaneously. In the pressure increasing process, first, the hydraulic pressure larger than the spring force of the spring 114 is obtained. Acts on the lock piston 104 so that the lock piston 104 moves backward, and then acts on the small piston 86 rather than the forward pressing force acting on the parking piston 103 by the hydraulic pressure of the parking control hydraulic chamber 106. The hydraulic pressure in the reverse direction and the resultant force of the clutch spring 93 increase and the parking piston 103 moves backward. As a result, the lock mechanism 105 is unlocked and the parking brake state is released.

  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 first and first wheels are braked by operating the parking pedal 29. The parking brake hydraulic pressure corresponding to the operation amount of the parking pedal 29 while the upstream hydraulic pressure passages 3Au, 3Bu and the downstream hydraulic pressure passages 3Ad, 3Bd of the two output hydraulic pressure passages 3A, 3B are blocked by the parking cylinder 4. Is output from the front and rear output hydraulic pressure chambers 23, 24 of the parking cylinder 4 to the downstream hydraulic pressure passages 3Ad, 3Bd to control the opening / closing of the control valve 66B as hydraulic pressure control means.

  Next, the operation of this embodiment will be described. When the parking control hydraulic pressure is applied to the back surface of the parking piston 103, the parking piston 103 moves forward and the lock mechanism 105 mechanically locks the advance position of the parking piston 103. Therefore, the parking brake state can be obtained automatically, and when the parking brake state is released, the parking release control hydraulic pressure only needs to be applied to the lock mechanism 105. In the parking brake state, there is no power consumption. The parking brake state can be obtained automatically with a simple structure.

  Moreover, in the middle of the first and second output hydraulic pressure paths 3A and 3B for guiding the output hydraulic pressure of the master cylinder M to the left front wheel and right front wheel brakes 2A and 2C, the output hydraulic pressure paths 3A and 3B are provided. A parking cylinder 4 is provided, which is divided into upstream hydraulic pressure paths 3Au and 3Bu on the master cylinder M side and downstream hydraulic pressure paths 3Ad and 3Bd on the left front wheel and right front wheel brakes 2A and 2C side. The parking cylinder 4 is provided with a parking brake according to the operation amount of the parking pedal 29 while blocking between the upstream hydraulic pressure passages 3Au, 3Bu and the downstream hydraulic pressure passages 3Ad, 3Bd according to the operation of the parking pedal 29. Hydraulic pressure can be output to the downstream hydraulic pressure paths 3Ad, 3Bd, and the hydraulic pressure in the downstream hydraulic pressure paths 3Ad, 3Bd is controlled by the control valves 66A, 66B. More, it is possible to obtain a parking control fluid pressure and the parking release control fluid pressure.

  That is, by operating the brake pedal P during service braking, the brake fluid pressure output from the master cylinder M is applied to the left front wheel brakes 2A, 2C and the left rear wheel brakes 2D, 2B. By operating the parking pedal 29 during parking brake, the parking brake state of the left front wheel brakes 2A and 2C and the right front wheel brakes 2A and 2C are obtained by the hydraulic pressure output from the parking cylinder 4 and the parking brake state is released. Although the system has two operation systems, the downstream hydraulic pressure passages 3Ad and 3Bd, which are transmission systems, are partially shared by the service brake and the parking brake, and it is unnecessary to use an electric motor or pump. And avoid cost increase It is possible to avoid the large.

  In the above embodiment, the control valves 66A and 66B are interposed between the brake hydraulic pressure chamber 80 and the parking control hydraulic pressure chamber 106, and the communication path 115 is connected between the brake hydraulic pressure chamber 80 and the parking release control hydraulic pressure chamber 109. The parking piston 103 and the lock piston 104 are operated with a time difference according to changes in the hydraulic pressure in the brake hydraulic pressure chamber 80, the parking control hydraulic pressure chamber 106, and the parking release control hydraulic pressure chamber 109. However, in order to ensure the operation with such a time difference, an electromagnetic on-off valve may be provided in the communication passage 115, and instead of the control valves 66A and 66B. The brake fluid pressure chamber 80 and the parking control fluid pressure chamber 106 communicate with each other, and the brake fluid pressure chamber 80 and the park Between grayed release control fluid pressure chamber 109 may be used a three-way electromagnetic valve for switching the state of communicating.

  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

2A, 2C: Wheel brakes 3A, 3B ... Hydraulic pressure paths 3Au, 3Bu ... Upstream hydraulic pressure paths 3Ad, 3Bd ... Downstream hydraulic pressure paths 4 ... Parking cylinders 29 ... Parking Parking pedals 66A, 66b as operating members ... Control valve 102 as hydraulic pressure control means ... Casing 103 ... Parking piston 105 ... Lock mechanism M ... Master cylinder P ... Brake operating member As brake pedal

Claims (1)

  A master cylinder (M) that generates hydraulic pressure in accordance with the amount of operation of the brake operating member (P), and wheel brakes (2A, 2C) that are braked by the action of the hydraulic pressure generated in the master cylinder (M); A parking piston (slidably fitted to the casing (102) to enable the parking brake state of the wheel brakes (2A, 2C) to be obtained by a forward operation according to the action of the control fluid pressure for parking on the back surface. 103), and the parking piston (103) is automatically locked according to the forward operation of the parking piston (103) to mechanically lock the parking piston (103) at the forward position, and according to the action of the parking release control hydraulic pressure. An unlocking operation is provided in the casing (102) behind the parking piston (103). And a hydraulic path (3A, 3B) for guiding the output hydraulic pressure of the master cylinder (M) to the wheel brakes (2A, 2C) side of the upstream fluid on the master cylinder (M) side. The pressure passages (3Au, 3Bu) and the downstream hydraulic pressure passages (3Ad, 3Bd) on the wheel brake (2A, 2C) side are divided in the middle of the hydraulic pressure passages (3A, 3B). According to the operation of the parking operation member (29), the operation amount of the parking operation member (29) is reduced while the upstream hydraulic pressure passage (3Au, 3Bu) and the downstream hydraulic pressure passage (3Ad, 3Bd) are blocked. The parking cylinder (4) capable of outputting the corresponding hydraulic pressure to the downstream hydraulic pressure passage (3Ad, 3Bd) and the hydraulic pressure in the downstream hydraulic pressure passage (3Ad, 3Bd) to control the parking control fluid Pressure and said parkin Possible to obtain a release control fluid pressure and the fluid pressure control means (66A, 66B) and parking brake system, characterized in that it comprises a.

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