JP4552529B2 - Common use parking brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a common use and parking brake system capable of avoiding a reduction in parking brake force caused by pressure removal when removing pressure at the time of its operation as a parking brake. <P>SOLUTION: In the brake system A, a lead at an engaged portion between a male screw section 27a (second fixed screw element) of a screw shaft 27 and a female screw section 29a (second movable screw element) of a nut 29 is set to be small when compared with a lead at an engaged portion between a female screw section 19a (first fixed screw element) of a piston 19 and a male screw section 25a (first movable screw element) of a second piston 25. Thus, the second piston 25 and nut 29 are integral each other via a frictional clutch FC by making the second piston 25 and nut 29 move to a control chamber R2 while the second piston 25 and nut 29 are integrally rotated via the frictional clutch FC, and a contact portion between a screwed surface of the male screw section 27a and a screwed surface of the female screw section 29a and a contact portion between a screw surface of the female screw section 19a and a screw surface of the male screw section 25a turn stretched. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  INDUSTRIAL APPLICABILITY The present invention can be employed as a vehicle brake device, and can generate braking force by brake hydraulic pressure when used as a parking brake as well as when used as a parking brake. When used as a parking brake, the present invention relates to a service and parking brake device configured to be mechanically locked and maintain the braking force after generating a braking force.

This type of common and parking brake device is described, for example, in Patent Document 1 below, and in FIG. 4 of Patent Document 1, the cylinder cannot rotate around the cylinder axis and can move in the cylinder axis direction. The piston is assembled to form a hydraulic chamber in the cylinder, and the piston is pushed by the brake fluid supplied to the hydraulic chamber to engage the braked rotating body. An adjustment nut that includes a brake lining that brakes the braked rotating body, and that is assembled to the cylinder so as to be rotatable about the cylinder axis and movable in the cylinder axis direction in the hydraulic chamber, and the adjustment nut Provided between the cylinder and the adjustment nut in an unlocked state where the adjustment nut is in a fixed position, and the adjustment nut can be rotated. A friction clutch that disables rotation of the adjustment nut in a locked state moved in a predetermined direction, a male screw portion of an adjustment spindle that is provided integrally with the piston, and a male screw portion that is provided integrally with the adjustment nut. And an adjustment timing of the friction clutch can be automatically adjusted by automatically adjusting a distance between the piston and the adjusting nut according to a wear amount of the brake lining. An ordinary and parking brake device comprising an adjusting device and an electromagnetic actuator that is pushed by the piston and is capable of holding the friction clutch in an engaged state in a state where the brake lining brakes the braked rotating body. It is shown.
JP 2000-504811 A

  In the above-mentioned common and parking brake device of Patent Document 1, it is possible to keep the friction clutch in a non-engaged state by turning the electromagnetic actuator in a non-actuated state (non-energized state). It is possible to move the piston connected in the cylinder axial direction through the adjusting nut and the adjusting device. Therefore, at this time, the piston can be advanced and retracted in the cylinder axial direction by supplying and discharging the brake fluid to and from the hydraulic pressure chamber, and the device can be operated as a service brake.

  In addition, the friction clutch can be held in the engaged state by setting the electromagnetic actuator to the operating state (energized state), and the rotation of the adjusting nut is restricted and the adjusting nut is connected to the adjusting device via the adjusting device. It is possible to restrict the movement of the piston in the cylinder axial direction. For this reason, the brake fluid is pressurized and supplied to the hydraulic chamber, and the piston is moving forward in the cylinder axial direction (braking where the brake lining is pushed by the piston and is engaged with the braked rotor). If the friction clutch is engaged with the electromagnetic actuator in the activated state, the rotation of the adjustment nut is restricted, and the cylinder connected to the adjustment nut and the adjustment device via the cylinder is moved in the axial direction. By regulating, it is possible to maintain the braking state even if the brake fluid is discharged from the hydraulic chamber, and the brake device can be operated as a parking brake.

  By the way, in the above-mentioned common and parking brake device of Patent Document 1, in order to operate the brake device as a parking brake, the electromagnetic actuator is operated in a state where the brake fluid is pressurized and supplied to the hydraulic chamber. When the friction clutch is engaged, the threaded portion of the adjusting screw's male threaded portion and the adjusting nut's female threaded portion is pulled, and when the pressure is released thereafter (when brake fluid is no longer supplied to the hydraulic pressure chamber) ), The piston is pushed back by the screw gap existing in the threaded portion of the male threaded portion of the adjusting spindle and the female threaded portion of the adjusting nut by the reaction force from the brake lining. For this reason, it is inevitable that the parking brake force is reduced due to the piston being pushed back by the amount corresponding to the screw gap.

  The present invention has been made to solve the above-described problem, and is a piston that is assembled to a cylinder so as not to rotate around the cylinder axis and to be movable in the cylinder axis direction, and forms a hydraulic chamber in the cylinder. And the piston is pushed by being pushed out by the brake fluid supplied to the hydraulic pressure chamber and is engaged with the braked rotating body to brake the braked rotating body. It is provided in the room so that it can rotate around the cylinder axis and can move from a fixed position to a moving position in the cylinder axis direction. The movement in the piston pushing direction is restricted at the fixed position, and the fixed position is set by the first biasing means. From the moving position to the fixed position by the second urging means having a urging force larger than the urging force of the first urging means. A moving body biased toward the cylinder axial direction, a first fixing screw element provided integrally with the piston in the hydraulic chamber, extending in the cylinder axial direction and having a predetermined lead, A screw surface that is paired with a screw surface of one fixed screw element is provided integrally with the moving body, and is screwed into the first fixed screw element with a predetermined screw gap in the cylinder axial direction. A first moving screw element that is coaxially disposed in the hydraulic chamber with respect to the first fixing screw element, and is provided integrally with the cylinder and extends in the cylinder axial direction, and the first fixing screw A second fixing screw element having a lead smaller than the lead of the element, and a screw face that is paired with the screw face of the second fixing screw element, and is rotatable about the cylinder axis in the hydraulic chamber; Provided to be movable in the cylinder axis direction The screw is screwed into the second fixing screw element with a predetermined screw clearance in the cylinder axial direction, the movement in the piston pushing direction is restricted at a fixed position, and is attached toward the fixed position by the third biasing means. The second moving screw element to be biased, the second moving screw element and the moving body can be engaged / disengaged, and the moving body and the second moving screw element are held in their respective fixed positions. When disengaged, the disengaged state is established, allowing relative rotation between the second moving screw element and the moving body, and the moving body moves from a fixed position toward a moving position by a predetermined amount or more. A friction clutch that is engaged when engaged with the second moving screw element and restricts relative rotation of the second moving screw element and the moving body, and when the friction clutch is in a non-engaged state, The moving body is in a fixed position against the second biasing means. And when the friction clutch is in an engaged state, the movable body and the second moving screw element are moved to the second biasing means and the third biasing element. There is a feature in the service and parking brake device provided with a drive device capable of moving in the cylinder axis direction toward the moving position against the biasing means.

  In the service and parking brake device according to the present invention, in order to operate the brake device as a parking brake, the brake fluid is pressurized and supplied to the hydraulic chamber (the piston is pushing the brake lining, In the state where the lining is engaged with the braked rotating body and brakes), the driving device is operated, and the moving body is moved from the fixed position toward the moving position against the second biasing means in the cylinder axis direction. When the moving body is moved to a predetermined position or more from the home position to the moving position, the second moving screw element is engaged and the friction clutch is engaged. For this reason, when the moving body moves more than a predetermined amount from the fixed position toward the moving position, the moving body and the second moving screw element rotate together in a state where the relative rotation is restricted by the engaged friction clutch. While moving in the cylinder axis direction.

  By the way, in the brake device, the lead in the screwed portion of the second fixed screw element and the second moving screw element is made smaller than the lead in the screwed portion of the first fixed screw element and the first moving screw element. Therefore, the moving body and the second moving screw element move in the cylinder axis direction while rotating integrally via the friction clutch, so that the cylinder axis line at the threaded portion of the second fixed screw element and the second moving screw element After the screw gap in the direction disappears on the moving direction side of the second moving screw element, the anti-moving direction side screw surface of the second fixed screw element and the moving direction side screw surface of the second moving screw element abut, The screw clearance in the cylinder axis direction at the threaded portion of the first fixed screw element and the first moving screw element disappears on the side opposite to the moving direction of the first moving screw element, and the moving direction side screw surface of the first fixed screw element And 1st moving screw required Anti moving direction side thread surface of the contacts, integral rotation of the moving body and the second moving screw element is stopped.

  In this state, the moving body and the second moving screw element are integrated with each other via the engaged friction clutch, the contact surface between the screw surface of the second fixed screw element and the screw surface of the second moving screw element, A contact portion between the screw surface of the fixed screw element and the screw surface of the first moving screw element is stretched. For this reason, even if the hydraulic pressure in the hydraulic chamber is lowered in this state and the piston is pushed back by the reaction force acting on the piston from the brake lining, the state in which both the abutting portions are stretched does not change. . Accordingly, if the design specifications of each configuration are set so that the frictional clutch and the above-described both contact portions do not slip due to the reaction force acting on the piston from the brake lining, the brake device is operated as a parking brake. At the time of depressurization, the piston is not pushed back in the cylinder axial direction and is mechanically locked. Thereby, in the said brake device, it is possible to avoid the fall of the parking brake force accompanying pressure reduction.

  In carrying out the present invention, the movable body is assembled to the cylinder so as to be rotatable about the cylinder axis and movable in the cylinder axis direction in the hydraulic chamber, and the hydraulic chamber is provided with the main chamber. A second piston partitioned into a control chamber, wherein the driving device is branched from a hydraulic circuit capable of supplying and discharging brake fluid to and from the main chamber, and a branched hydraulic circuit capable of supplying and discharging brake fluid to and from the control chamber It is also possible to be a switching valve that is interposed and is capable of switching communication / blocking between the main chamber and the control chamber. In this case, there is no need to worry about the liquid resistance, sealing performance, heat resistance, etc. of the electrical equipment because the electrical equipment is not incorporated in the hydraulic chamber in the cylinder, and the brake device is highly reliable. Is possible.

  In this case, a reservoir capable of storing brake fluid discharged from the control chamber when communication between the main chamber and the control chamber is interrupted may be connected to the switching valve. In this case, the hydraulic pressure difference between the main chamber acting on the second piston and the control chamber can be increased, and the operation response of the second piston can be improved. It is possible to improve the operation responsiveness.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 schematically shows an embodiment in which the present invention is applied to a movable caliper type disc brake, and a service and parking brake device A of this embodiment is a master cylinder MC that operates in response to a depression operation of a brake pedal BP. And a brake fluid pressure control unit CU capable of skid control and traction control, the brake system for a four-wheel vehicle is employed for left and right rear wheels (one is not shown). In this brake system for a four-wheeled vehicle, normal disc brake devices (not shown) are employed for the left and right front wheels.

  The regular / parking brake device A includes an inner pad 13 and an outer pad 15 that sandwich and brake a disc rotor 11 (a braked rotating body that rotates integrally with a wheel (not shown)) from the inside and the outside. A movable caliper 17 and a cup-shaped piston 19 are provided to push 13 and 15 toward the disk rotor 11. The pads 13 and 15 and the movable caliper 17 are each mounted to a mounting (not shown) mounted on the vehicle body so as to be slidable along the rotor axial direction.

  The inner pad 13 is composed of a brake lining 13a and a back plate 13b, and can be engaged / disengaged with respect to the disc rotor 11 by the brake lining 13a, and by a piston 19 assembled to the cylinder 17a of the movable caliper 17. The disc rotor 11 is configured to be pushed toward the disc rotor 11. On the other hand, the outer pad 15 is constituted by a brake lining 15a and a back plate 15b, and can be engaged / disengaged with respect to the disc rotor 11 by the brake lining 15a. The reaction claw portion 17b of the movable caliper 17 allows the disc rotor to 11 is configured to be pushed toward the head 11.

  The piston 19 is assembled to the cylinder 17a of the movable caliper 17 through the piston seal 21 so as not to rotate around the cylinder axis and to be movable in the cylinder axis direction (substantially parallel to the rotor axis direction). A hydraulic chamber Ro filled with brake fluid is formed inside. The hydraulic chamber Ro is connected to a hydraulic circuit 23a that constitutes a part of the brake hydraulic circuit 23, and brake fluid can be supplied and discharged through the hydraulic circuit 23a. The piston seal 21 is configured to be deformed toward the rotor side when the piston 19 is pressed toward the disk rotor 11, and has a function of pulling back the piston 19 by returning the deformation when the pressure is released ( Retract function).

  In this embodiment, the second piston 25, the screw shaft 27, and the nut 29 are incorporated in the cylinder 17a of the movable caliper 17, and the first spring 31, the thrust bearing 32, the second spring 33, and the thrust bearing 34 are incorporated. Is assembled. Further, a switching valve 41 is interposed in a branch hydraulic pressure circuit 23b branched from the hydraulic pressure circuit 23a, and a reservoir 43 is connected.

  The second piston 25 is assembled in the hydraulic chamber Ro to the cylinder 17a via a seal cup 26 so as to be rotatable around the cylinder axis and movable between a fixed position and a moving position in the cylinder axis direction. The interior of the hydraulic chamber Ro is divided into a main chamber R1 and a control chamber R2. The main chamber R1 is connected to a hydraulic circuit 23a, and brake fluid can be supplied and discharged through the hydraulic circuit 23a. On the other hand, the control chamber R2 is connected to the branch hydraulic circuit 23b, and can supply and discharge brake fluid through the branch hydraulic circuit 23b.

  The second piston 25 is urged in the cylinder axial direction by the first spring 31 via the thrust bearing 32 from the fixed position to the moving position (toward the right in FIG. 1). As shown, the piston 19 is pushed in the pushing direction (leftward in FIG. 1) at a fixed position where the L-shaped retainer portion of the thrust bearing 32 abuts the annular stepped portion of the holder 18 that is liquid-tightly fixed in the cylinder 17a. ) Movement is restricted. Further, the second piston 25 is integrally provided with a male screw portion 25a that is screwed into a female screw portion 19a that is integrally provided with the piston 19 as a separate member.

  The female screw portion 19a provided on the piston 19 is a first fixed screw element having a predetermined lead, and extends in the cylinder axial direction in a state exposed to the main chamber R1. The male screw portion 25 a of the second piston 25 is a first moving screw element that is screwed into the female screw portion 19 a provided in the piston 19 with a predetermined screw gap in the cylinder axial direction. It has a screw surface which makes a pair with the screw surface of the female screw portion 19a provided on the screw.

  The screw shaft 27 has a male screw portion 27a as a second fixing screw element having a smaller lead than the lead of the first fixing screw element, and is opposed to the female screw portion 19a provided on the piston 19. In the state arrange | positioned coaxially, it is integrally provided in the cylinder 17a via the holder 18, and is extended in the cylinder axial direction in the state exposed to control room R2.

  The nut 29 is provided in the control chamber R <b> 2 so as to be rotatable about the cylinder axis and movable in the cylinder axis direction, and the thrust bearing 36 is mounted by the third spring 35 having a larger urging force than the urging force of the first spring 31. As shown in FIG. 1, the piston 19 is pushed in the pushing direction (FIG. 1) at a fixed position contacting the stopper 28 fixed to the tip of the screw shaft 27. To the left) is restricted.

  The nut 29 has a female screw portion 29a as a second moving screw element. The female threaded portion 29a of the nut 29 is screwed into the male threaded portion 27a of the threaded shaft 27 with a predetermined screw clearance in the cylinder axial direction, and is a screw that makes a pair with the threaded surface of the male threaded portion 27a. Has a surface. Further, the nut 29 has a tapered portion 29b having a small diameter on the outer periphery of the second piston 25, and this tapered portion 29b is engaged / disengaged with the tapered portion 25b formed on the second piston 25. The friction clutch FC is configured by the tapered portion 29b of the nut 29, the tapered portion 25b of the second piston 25, the springs 31, 33, 35, and the like.

  The friction clutch FC can engage / disengage the second piston 25 and the nut 29, and is disengaged when the second piston 25 and the nut 29 are held in their respective fixed positions and are not engaged. In this state, the second piston 25 and the nut 29 are allowed to rotate relative to each other. When the second piston 25 moves from the fixed position to the moving position by a predetermined amount or more and engages with the nut 29, the engagement is achieved. In this state, the relative rotation of the second piston 25 and the nut 29 is limited.

  The switching valve 41 is a three-port two-position electromagnetic switching valve that is controlled to be energized / de-energized by the electric control unit ECU, and is branched from a hydraulic circuit 23a capable of supplying and discharging brake fluid to and from the main chamber R1. In addition, a branch hydraulic circuit 23b capable of supplying and discharging brake fluid is provided, and the communication between the main chamber R1, the control chamber R2, the control chamber R2, and the reservoir 43 can be switched. In the switching valve 41, the main chamber R1 and the control chamber R2 communicate with each other when not energized, and the liquid flow to the reservoir 43 is blocked by the built-in check valve 41a. When energized, the main chamber R1 and the control chamber R2 The communication between the control chamber R2 and the reservoir 43 is made possible, and the liquid flow from the control chamber R2 to the reservoir 43 becomes possible.

  The reservoir 43 is connected to the switching valve 41 and can store brake fluid discharged from the control chamber R2 when the communication between the main chamber R1 and the control chamber R2 is blocked by the switching valve 41. The brake fluid stored in the reservoir 43 is communicated between the main chamber R1 and the control chamber R2 by the switching valve 41 when no brake fluid is supplied from the brake fluid pressure control unit CU to the branch fluid pressure circuit 23b. In addition, it is configured to be discharged toward the branch hydraulic circuit 23b through the check valve 41a.

  The brake hydraulic pressure control unit CU is controlled by the electric control unit ECU in a well-known manner when the vehicle is running, and can perform skid control and traction control, and can operate the parking brake switch SW when the vehicle is stopped. The operation of the common / parking brake device A can be controlled by controlling the operation together with the switching valve 41 by the electric control unit ECU. The configuration of the brake fluid pressure control unit CU is well known per se, and the description thereof is omitted.

  In the service and parking brake device A of the present embodiment configured as described above, the parking valve switch SW is turned off, and the switching valve 41 is in a non-energized state when used as a service brake. The main chamber R1 and the control chamber R2 are always in communication, and their internal pressures are the same, and the flow of brake fluid from the branch hydraulic circuit 23b to the reservoir 43 is regulated by the check valve 41a in the switching valve 41. Has been.

  For this reason, in this state (normal brake state), the hydraulic pressure difference between the main chamber R1 and the control chamber R2 is always zero, and the pushing force due to the hydraulic pressure difference does not act on the second piston 25. Therefore, as shown in FIG. 1, the second piston 25 and the nut 29 are held in their respective fixed positions by the action of the springs 33 and 35, and the friction clutch FC is maintained in the non-engaged state. Yes.

  By the way, in this regular brake state, when the brake pedal BP is depressed, the brake fluid is pressurized and supplied from the master cylinder MC to the hydraulic circuit 23a via the brake hydraulic pressure control unit CU, and from the hydraulic circuit 23a. The brake fluid is pressurized and supplied to the main chamber R1, and the brake fluid is pressurized and supplied from the hydraulic circuit 23a to the control chamber R2 through the branch hydraulic circuit 23b and the switching valve 41.

  Therefore, at this time, as shown in FIG. 2, the second piston 25 and the nut 29 are provided in the piston 19 with the brake fluid pressurized and supplied to the main chamber R1 and the control chamber R2, as shown in FIG. The piston 19 can be advanced in the cylinder axial direction within the range of the screw gap between the female screw portion 19a and the male screw portion 25a of the second piston 25, and the brake device A is operated as a service brake. Is possible.

  Accordingly, at this time, the brake fluid pressurized and supplied to the main chamber R1 causes the piston 19 to be pushed toward the disc rotor 11 in the cylinder axial direction while deforming the piston seal 21 toward the rotor, thereby causing the inner pad 13 to move. Is pressed against the disk rotor 11, and the reaction force causes the movable caliper 17 to be pushed toward the inner side, and the reaction claw portion 17 b of the movable caliper 17 presses the outer pad 15 against the disk rotor 11. Further, the force generated when both pads 13 and 15 press the disk rotor 11 is received by a mounting (not shown) that supports both pads 13 and 15 and generates a braking force that prevents the rotation of the disk rotor 11. Let In this braking state, the structural members such as the movable caliper 17 are bent and deformed in response to the pressure supply of the brake fluid.

  Further, when the depression of the brake pedal BP is released and the pressure supply of the brake fluid from the master cylinder MC to the main chamber R1 and the control chamber R2 is removed and the pressure is released, the above-described deformation of the piston seal 21 occurs. By the retract function obtained by returning and the retract function obtained by returning the bending deformation of the constituent members such as the movable caliper 17, the piston 19 moves to the inner side, and the movable caliper 17 moves to the outer side. Returning to the non-braking state of FIG. 1 from the braking state 2, the pushing and pressing of the pads 13 and 15 to the disk rotor 11 are removed. Thereby, the rotational braking of the disk rotor 11 by both the pads 13 and 15 is released.

  Further, when the piston 19 moves forward in the cylinder axial direction in the normal brake state described above, for example, due to wear of the brake linings 13a and 15a, the female thread portion 19a provided on the piston 19 and the second piston 25 When the piston 19 advances more than the screw gap between the male screw portions 25a, the state shown in FIG. 4 is obtained through the state shown in FIG. 3, and the second piston 25 rotates at a fixed position, The amount of screwing between the female screw portion 19a provided on the piston 19 and the male screw portion 25a of the second piston 25 is automatically adjusted.

  Note that the brake fluid is released from the main chamber R1 and the control chamber R2 after the screwing amount between the female screw portion 19a provided on the piston 19 and the male screw portion 25a of the second piston 25 is adjusted. Accordingly, the piston 19 moves to the inner side and the movable caliper 17 moves to the outer side by the retract function described above, and returns from the braking state of FIG. 4 to the non-braking state of FIG.

  In the common and parking brake device A of this embodiment, when the parking brake switch SW is turned on and turned on, and the brake device A is used as a parking brake, first, the switching valve In a state where 41 is in a non-energized state by the electric control unit ECU, the brake hydraulic pressure control unit CU is brought into a pressurization control state by the electric control unit ECU, and the brake hydraulic pressure control unit CU receives the brake device A from the brake hydraulic pressure control unit CU. A predetermined amount of brake fluid is pressurized and supplied to the main chamber R1 and the control chamber R2.

  As a result, the same operation as when the brake pedal BP is depressed in the above-described normal brake state is obtained, and the brake device A can be operated as a parking brake. Thereafter, the hydraulic pressure supplied from the brake hydraulic pressure control unit CU to the brake device A in a state where the brake fluid can be pressurized and supplied from the brake hydraulic pressure control unit CU to the main chamber R1 of the brake device A. 6 reaches the set value, as shown in FIG. 6, the switching valve 41 is energized by the electric control unit ECU, and the brake fluid can flow into the reservoir 43 from the control chamber R2.

  In this state, a hydraulic pressure difference is generated between the main chamber R1 and the control chamber R2, and the second piston 25 opposes the second spring 33 from the fixed position shown in FIG. 6 to the moving position shown in FIG. Move in the cylinder axis direction. Thus, when the second piston 25 moves from the fixed position toward the moving position by a predetermined amount or more, the second piston 25 is engaged with the nut 29 and the friction clutch FC is engaged, and thereafter, The friction clutch FC is maintained in the engaged state by the urging force of the third spring 35. For this reason, the second piston 25 and the nut 29 move in the cylinder axial direction while integrally rotating in a state where the relative rotation is restricted by the engaged friction clutch FC.

  By the way, in the brake device A, the lead in the threaded portion of the male screw portion 27a (second fixed screw element) of the screw shaft 27 and the female screw portion 29a (second moving screw element) of the nut 29 is the female of the piston 19. The screw portion 19a (first fixed screw element) and the male screw portion 25a (first moving screw element) of the second piston 25 are made smaller than the lead in the threaded portion. For this reason, the second piston 25 and the nut 29 move in the cylinder axial direction while rotating integrally through the friction clutch FC, so that the male thread portion 27a ( The screw gap in the cylinder axis direction at the threaded portion of the second fixed screw element) and the female screw portion 29a (second moving screw element) of the nut 29 disappears on the moving direction side of the female screw portion 29a, and the male screw portion As shown in FIG. 8, after the abutting side screw surface of 27 a (second fixing screw element) and the moving direction side screw surface of female screw portion 29 a (second moving screw element) abut, The screw gap in the cylinder axial direction at the threaded portion of the female screw portion 19a (first fixed screw element) and the male screw portion 25a (first moving screw element) of the second piston 25 is on the side opposite to the moving direction of the male screw portion 25a. Disappears at female screw part 1 The movement direction side thread surface of a (first fixed screw element) and the opposite movement direction side thread surface of the male screw portion 25a (first movement screw element) abut, and the second piston 25 and the nut 29 rotate integrally. Stops.

  In this state, as shown in FIG. 8, the second piston 25 and the nut 29 are integrated with each other through the engaged friction clutch FC, and the screw surface of the male screw portion 27a (second fixing screw element) and the female screw The contact portion of the screw surface of the screw portion 29a (second moving screw element), the contact surface of the female screw portion 19a (first fixed screw element) and the screw surface of the male screw portion 25a (first moving screw element). Stretching the contact. Therefore, in this state, the brake hydraulic pressure control unit CU is changed from the pressurization control state to the depressurization control state by the electric control unit ECU, the hydraulic pressure in the main chamber R1 is lowered, and the brake lining 13a acts on the piston 19. Even if the piston 19 is pushed back by the reaction force, the state in which both the abutting portions are stretched (the state in which each screw surface is in pressure contact with each abutting portion) does not change.

  Accordingly, if the design specifications of each component are set so that the reaction force acting on the piston 19 from the brake lining 13a does not cause a slip at the friction clutch FC and the above-described both contact portions, the brake device A is parked. At the time of pressure release when operating as a brake, the piston 19 is not pushed back in the cylinder axis direction and is mechanically locked. Thereby, in the said brake device A, it is possible to avoid the fall of the parking brake force accompanying pressure reduction.

  When the brake fluid pressure control unit CU is changed from the pressurization control state to the depressurization control state by the electric control unit ECU, the switching valve 41 is turned off by the electric control unit ECU. The brake fluid flowing into the reservoir 43 from the control chamber R2 in the operation shown in FIGS. 6 to 8 is discharged toward the branch hydraulic circuit 23b through the check valve 41a.

  Further, in the common and parking brake device A of this embodiment, when the parking brake switch SW is turned off from the state where the parking brake switch SW is turned on and the operation of the parking brake described above is released, first, the switching valve 41 is opened. The brake fluid pressure control unit CU is brought into a pressurization control state by the electric control device ECU in a state where it is not energized by the electric control device ECU, and the main chamber of the brake device A is transmitted from the brake fluid pressure control unit CU. The brake fluid is pressurized and supplied to R1 and the control chamber R2.

  Thus, when the piston pushing force due to the hydraulic pressure becomes larger than the reaction force acting on the piston 19 from the brake lining 13a described above, the thread surface of the female screw portion 19a (first fixing screw element) and the male screw portion 25a (first moving screw). The pressure contact of the screw surface of the element) is released, the contact portion of the screw surface of the male screw portion 27a (second fixed screw element) and the screw surface of the female screw portion 29a (second moving screw element), and the female screw portion The state where the contact portion between the screw surface of 19a (first fixed screw element) and the screw surface of male screw portion 25a (first moving screw element) is stretched is eliminated.

  Therefore, in this state, as shown in FIGS. 9 to 11, the second piston 25 and the nut 29 are rotated while being integrally rotated via the friction clutch FC by the urging force of the springs 33 and 35. It moves in the cylinder axial direction toward the position, and returns to the same state (see FIG. 6) as in the initial pressurizing operation of the parking brake operation described above. Note that at the initial stage when the second piston 25 and the nut 29 move from the moving position toward the fixed position, the lead of the female screw portion 19a (first fixed screw element) and the male screw portion 25a (first moving screw element). However, in the middle and late stages, it rotates and moves according to the leads of the male screw portion 27a (second fixing screw element) and the female screw portion 29a (second moving screw element). Further, after the nut 29 has finished moving to the home position, the friction clutch FC is disengaged, and only the second piston 25 moves toward the home position in the cylinder axial direction by the biasing force of the second spring 33. To do.

  In addition, after the second piston 25 and the nut 29 are returned to their home positions by the urging forces of the springs 33 and 35, the brake fluid pressure control unit CU controls the pressure removal from the pressurization control state by the electric control unit ECU. Since the brake fluid can be discharged from the main chamber R1 and the control chamber R2, the piston 19 and the movable caliper 17 return to the non-braking state shown in FIG. 1 or FIG. The parking brake is released.

  Further, in the common and parking brake device A of this embodiment, the second piston 25 and the nut 29 are resisted against the springs 33 and 35 by the hydraulic pressure difference generated between the main chamber R1 and the control chamber R2, as shown in FIG. 8 is configured to move in the cylinder axial direction from the respective fixed positions shown in FIG. 8 toward the moving position shown in FIG. 8, and no electric device is incorporated in the hydraulic chamber Ro in the cylinder 17 a of the movable caliper 17. In addition, there is no need to worry about the liquid resistance, sealing properties, heat resistance, and the like of the electrical equipment, and the device can be made highly reliable.

  In the common and parking brake device A of this embodiment, the reservoir 43 that can store the brake fluid discharged from the control chamber R2 when the communication between the main chamber R1 and the control chamber R2 is shut off is the switching valve 41. It is connected to the. Therefore, the main chamber acting on the second piston 25 when the brake fluid is pressurized and supplied to the main chamber R1 in a state where the communication between the main chamber R1 and the control chamber R2 is blocked by the switching valve 41. The hydraulic pressure difference between R1 and the control chamber R2 can be increased, and the operation response of the second piston 25 can be improved, whereby the operation response of the parking brake can be improved. .

  In the service and parking brake device A of this embodiment, when the brake device A is used as a service brake, the second piston 25 and the nut 29 are held in their respective fixed positions even during adjustment. Since the friction clutch FC is held in the disengaged state, the piston 19 can be efficiently pushed by the brake fluid pressure supplied to the main chamber R1 under pressure.

  In the above-described embodiment, the female screw portion 19a provided on the piston 19 is the first fixed screw element, the male screw portion 25a of the second piston 25 is the first moving screw element, and the male screw portion 27a of the screw shaft 27 is used. Is the second fixed screw element, and the female screw portion 29a of the nut 29 is the second moving screw element. However, the male screw portion and the female screw portion may be reversed. In the above embodiment, the screw diameters of the first fixed screw element and the first moving screw element are configured to be different from the screw diameters of the second fixed screw element and the second moving screw element. It is also possible to configure and implement such that the screw diameters are substantially the same.

  In the above-described embodiment, the present invention is implemented by providing the reservoir 43. However, the present invention can also be practiced without this. In the embodiment in which the reservoir 43 is eliminated, the same function as that of the reservoir 43 is secured by expansion of the pipeline in the branch hydraulic circuit 23b, and the switching valve 41 is implemented as a 2-port 2-position electromagnetic on-off valve. In the above embodiment, an example in which the present invention is applied to a disc brake (a brake in which the braked rotating body is a disc rotor) has been described. However, the present invention is a drum brake (a brake in which the braked rotating body is a brake drum). ) Can be implemented with appropriate modifications.

  Further, in the above-described embodiment, one switching valve 41 of the three-port two-position electromagnetic switching valve is adopted, and the main chamber R1 and the control chamber R2 are communicated when not energized, and the main chamber R1 and the control chamber R2 are energized when energized. However, the main chamber R1 and the control chamber R2 are communicated when energized, and the main chamber R1 and the control chamber R2 are communicated when de-energized. It is also possible to implement the present invention by adopting a switching valve configured to be blocked and allow brake fluid to flow into the reservoir 43 from the control chamber R2. In these cases, for example, two 2-port 2-position electromagnetic switching valves can be employed.

  In the above-described embodiment, the second piston 25 is moved from the fixed position to the moving position against the second spring 35 due to a hydraulic pressure difference generated between the main chamber R1 and the control chamber R2 by the operation of the switching valve 41. However, the second piston (25) is resisted against the second spring (35) by the magnetic force obtained by the operation of the electromagnetic actuator assembled to the cylinder (17a). Thus, the present invention can be configured and implemented so as to move in the cylinder axis direction from the fixed position toward the moving position.

  Further, in the above-described embodiment, when the brake device A is used as a parking brake, the brake fluid is pressurized and supplied from the brake fluid pressure control unit CU to the main chamber R1 and the control chamber R2. However, when the brake device A is used as a parking brake, the brake fluid can be pressurized and supplied from the master cylinder MC to the main chamber R1 and the control chamber R2. is there.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows roughly one Embodiment of the brake system containing the regular and parking brake apparatus (non-braking state) by this invention. It is operation | movement explanatory drawing of the state which is operating the common and parking brake apparatus shown in FIG. 1 as a service brake. It is operation | movement explanatory drawing when the service and parking brake apparatus shown in FIG. 1 operate | moves as a service brake at the time of lining wear. FIG. 7 is an operation explanatory diagram when the screwing amount between the internal thread portion of the piston and the external thread portion of the second piston is adjusted in the common and parking brake device illustrated in FIG. 1. It is operation | movement explanatory drawing when a regular and parking brake apparatus is made into the non-operation state after the screwing amount between the internal thread part of a piston and the external thread part of a 2nd piston is adjusted. It is the 1st operation explanatory view when the common and parking brake device shown in Drawing 1 operates as a parking brake. It is the 2nd operation explanatory view when the common and parking brake device shown in Drawing 1 operates as a parking brake. FIG. 10 is a third operation explanatory diagram when the common and parking brake device shown in FIG. 1 operates as a parking brake. It is a 1st operation explanatory view when the common use parking brake device shown in Drawing 1 releases a parking brake. It is the 2nd operation explanatory view when the common use parking brake device shown in Drawing 1 releases a parking brake. FIG. 10 is a third operation explanatory diagram when the common and parking brake device shown in FIG. 1 releases the parking brake.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Disc rotor (braking rotating body), 13, 15 ... Pad, 13a, 15a ... Brake lining, 17 ... Movable caliper, 17a ... Cylinder, 17b ... Reaction claw part, 19 ... Piston, 19a ... Female thread part (first) 1 fixed screw element), 21 ... piston seal, 23 ... brake hydraulic circuit, 23a ... hydraulic circuit, 23b ... branch hydraulic circuit, 25 ... second piston (moving body), 25a ... male screw part (first Moving screw element), 25b ... tapered portion, 27 ... screw shaft, 27a ... male screw portion (second fixed screw element), 29 ... nut, 29a ... female screw portion (second moving screw element), 29b ... tapered portion, 31 ... 1st spring (1st biasing means), 32 ... Thrust bearing, 33 ... 2nd spring (2nd biasing means), 34 ... Thrust bearing, 35 ... 3rd spring (3rd biasing means), 36 ... Thrust bearings 41 ... switching valve, 43 ... reservoir, Ro ... hydraulic chambers, R1 ... main chamber, R2 ... control chamber, FC ... friction clutch, ECU ... electrical control, SW ... parking brake switch

Claims (3)

A piston that is assembled to the cylinder so that it cannot rotate around the cylinder axis and is movable in the cylinder axis direction, and forms a hydraulic chamber in the cylinder;
The piston is pushed by being pushed out by the brake fluid supplied to the hydraulic pressure chamber and is engaged with the braked rotating body, and includes a brake lining for braking the braked rotating body,
A first biasing means is provided in the hydraulic chamber so as to be rotatable around a cylinder axis and movable between a fixed position and a moving position in the cylinder axis direction, and the movement in the piston pushing direction is restricted at the fixed position. Is urged in the cylinder axial direction from the fixed position to the moving position by the second urging means having a larger urging force than the urging force of the first urging means from the moving position toward the fixed position. A moving body energized by
A first fixing screw element provided integrally with the piston in the hydraulic chamber, extending in a cylinder axial direction, and having a predetermined lead;
The first fixed screw element has a screw surface that is paired with the screw surface, and is provided integrally with the moving body, and has a predetermined screw gap in the cylinder axis direction and is screwed onto the first fixed screw element. A first moving screw element to be joined;
It is coaxially arranged with respect to the first fixed screw element in the hydraulic chamber, is provided integrally with the cylinder, extends in the cylinder axial direction, and is smaller than the lead of the first fixed screw element. A second securing screw element having a lead;
The second fixed screw element has a thread surface that is paired with the thread surface, and is provided in the hydraulic chamber so as to be rotatable about the cylinder axis and movable in the cylinder axis direction. A second moving screw element that is screwed into the second fixed screw element with a gap, restricted in movement in the piston pushing direction at a fixed position, and biased toward the fixed position by a third biasing means When,
The second moving screw element and the moving body can be engaged / disengaged, and the moving body and the second moving screw element are held in their respective fixed positions and are not engaged. The second moving screw element and the moving body are allowed to rotate relative to each other, and the moving body moves from a fixed position to a moving position by a predetermined amount or more and engages with the second moving screw element. A friction clutch that is sometimes engaged and limits relative rotation of the second moving screw element and the moving body;
When the friction clutch is in a non-engaged state, the moving body can be moved in the cylinder axial direction from the fixed position toward the moving position against the second urging means, and the friction clutch is engaged. When in the combined state, the movable body and the second moving screw element can be moved in the cylinder axial direction toward the moving position against the second urging means and the third urging means. Service and parking brake device equipped with the device.   2. The service / parking brake device according to claim 1, wherein the movable body is assembled to the cylinder so as to be rotatable about the cylinder axis and movable in the cylinder axis direction in the hydraulic chamber, and the hydraulic pressure is set. A second piston that divides the room into a main chamber and a control chamber, wherein the driving device is branched from a hydraulic circuit capable of supplying and discharging brake fluid to and from the main chamber, and can supply and discharge brake fluid to and from the control chamber An ordinary and parking brake device, characterized in that it is a switching valve that is interposed in a branch hydraulic circuit and is capable of switching between communication and blocking between the main chamber and the control chamber. The common / parking brake device according to claim 2, wherein the switching valve has a reservoir capable of storing brake fluid discharged from the control chamber when communication between the main chamber and the control chamber is interrupted. A common and parking brake device characterized by being connected.

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