JP2013072513A - Normal and parking brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a decrease in braking force due to axial deformation of an annular flange without causing any increase in weight of a screw shaft.SOLUTION: A normal and parking brake device 100 includes a cylinder 11, a piston 21 assembled in an in-cyclinder hole 11a of the cylinder 11, and a brake lining 31a pressed by the piston 21 against a braked rotary body (40), and also includes a nut member 61 and a screw shaft 62 which are connected to each other by screwing and an electric motor 71 capable of driving them. The screw shaft 62 has a rotary shaft part 62b in one side region, a male screw part 62b in the other end region, and an annular flange 62c in an intermediate region. At the annular flange 62c, a tapered engagement surface Sa is formed which faces the bottom wall surface 11b2 of the cylinder 11 while making the external diameter of the rotary shaft part 62a small and the external diameter of the annular flange 62c large, and a tapered bearing surface Sb which bears the engagement surface Sa rotatably is formed on the bottom wall surface 11b2 of the cylinder 11.

Description

  INDUSTRIAL APPLICABILITY The present invention can be employed as a brake device for a vehicle, can be used as a service brake, can be used as a parking brake, and when used as a parking brake, the braking force by hydraulic pressure and the driving force of an electric motor It is related with the service and parking brake apparatus comprised so that the braking force by both could be obtained and maintained mechanically.

  This kind of common and parking brake device is described in Patent Document 1 below, for example. The common and parking brake device described in Patent Document 1 below is a cylinder having a bottomed cylindrical shape and having a cylinder bore, and moves in the cylinder axial direction with respect to the cylinder bore of the cylinder It is possible and liquid-tightly assembled, and a piston that forms a hydraulic pressure chamber in the cylinder, and this piston is pushed by brake fluid supplied to the hydraulic pressure chamber to be pushed and covered. A brake lining that engages with the brake rotator and brakes the braked rotator, and is configured to obtain a brake force mechanically maintained by the driving force of the electric motor (nut member, Screw shaft, electric motor, etc.).

Special table 2007-519568 gazette

  In the above-mentioned common and parking brake device of Patent Document 1, the nut member is disposed coaxially with respect to the piston in the hydraulic pressure chamber, and is assembled so as not to rotate with respect to the piston. The brake lining side end can be brought into contact with and separated from the piston, and has an internal thread portion at the shaft center portion. The screw shaft is coaxially arranged with respect to the piston, and is attached to an insertion hole provided in the bottom wall of the cylinder, and has a rotating shaft portion that is rotatable about the cylinder axis with respect to the cylinder. An annular flange having a male threaded portion threadedly coupled to the female threaded portion of the nut member at the other end, and rotatably engaged with a bottom wall surface of the cylinder exposed to the hydraulic pressure chamber It has a portion at an intermediate portion, can be driven to rotate in both forward and reverse directions by an electric motor, and is restricted from moving in the cylinder axial direction with respect to the cylinder.

  In the above-mentioned common and parking brake device of Patent Document 1, it is possible to move the piston back and forth in the cylinder axis direction by supplying and discharging brake fluid to and from the hydraulic pressure chamber, and to obtain a braking force by hydraulic pressure. It is. Further, by rotating the screw shaft forward and backward with an electric motor, the nut member and the piston can be advanced and retracted in the cylinder axial direction, and a braking force can be obtained by the driving force of the electric motor. Therefore, it is possible to use the brake force due to the hydraulic pressure and the brake force due to the driving force of the electric motor as a service brake and as a parking brake. When the braking force is obtained by the driving force of the electric motor, the braking force is maintained by the self-locking function obtained between the electric motor and the nut member even if the driving force of the electric motor is removed. It is configured.

  By the way, in the regular and parking brake device of Patent Document 1 described above, the annular flange portion provided at the intermediate portion of the screw shaft is a disc shape orthogonal to the cylinder axis, and is formed in this annular flange portion. The engaging surface that faces the bottom wall surface of the cylinder and the receiving surface that is formed on the bottom wall surface of the cylinder and rotatably receives the engaging surface are both annular in a shape orthogonal to the cylinder axis. For this reason, in the state which maintained the shape (disk shape) of the annular flange part, the rigidity of the annular flange part may not be sufficiently increased. In this case, the hydraulic pressure and the electric motor are driven from the state where both the braking force (axial force) due to the hydraulic pressure and the braking force (axial force) due to the driving force of the electric motor are obtained (a state where high braking force is obtained). When the force is removed and the self-locking state is established, the axial force acting on the screw shaft by the drive of the electric motor is added to the axial force that presses the piston that the hydraulic pressure has shared. There is a risk of deformation more than necessary, and the axial force acting on the screw shaft may be unnecessarily reduced due to the deformation. In the above-described configuration, if the plate thickness of the annular flange portion is increased, the rigidity of the annular flange portion can be sufficiently increased. In this case, however, the vehicle mountability deteriorates as the axial length of the screw shaft increases. There is a possibility that new problems such as an increase in the weight of the screw shaft accompanying an increase in the plate thickness may occur.

The present invention has been made to solve the above problems,
A cylinder formed in a bottomed cylindrical shape and having a cylinder bore;
A piston that is movable in the cylinder axial direction and is fluid-tightly assembled with respect to the cylinder bore of the cylinder, and that forms a hydraulic chamber in the cylinder;
The piston is pushed by being pushed in the cylinder axial direction 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. ,
It is coaxially arranged with respect to the piston in the hydraulic chamber, is assembled so as not to rotate with respect to the piston and to be movable in the cylinder axial direction, and contacts the piston at the brake lining side end. A nut member that can be contacted / separated and has a female threaded portion in the shaft center;
A rotating shaft that is coaxially arranged with respect to the piston and is assembled in a liquid-tight manner to an insertion hole provided in the bottom wall of the cylinder via a seal ring, and is rotatable about the cylinder axis with respect to the cylinder And a male screw part screwed and connected to the female screw part of the nut member at the other end part, and is rotatable with respect to the bottom wall surface of the cylinder exposed to the hydraulic pressure chamber. A threaded shaft that has an annular flange portion to be engaged at an intermediate portion and is restricted from moving in the cylinder axial direction with respect to the cylinder;
An electric motor mounted on the cylinder and capable of rotating the screw shaft in both forward and reverse directions;
The annular flange portion has a small outer diameter of the rotating shaft portion, a large outer diameter of the annular flange portion, and a tapered engagement surface facing the bottom wall surface of the cylinder is formed.
The bottom wall surface of the cylinder is formed with a taper angle equal to the taper angle of the tapered engagement surface, and the tapered engagement surface is rotatably received (via a bearing or directly). The common and parking brake device having a tapered receiving surface is characterized.

  In the service and parking brake device according to the present invention, the piston can be advanced and retracted in the cylinder axial direction by supplying and discharging brake fluid to and from the hydraulic chamber, as in the service and parking brake device of Patent Document 1 described above. Yes, it is possible to obtain a braking force by hydraulic pressure. Further, by rotating the screw shaft forward and backward with an electric motor, the nut member and the piston can be advanced and retracted in the cylinder axial direction, and a braking force can be obtained by the driving force of the electric motor. Therefore, it is possible to use the brake force due to the hydraulic pressure and the brake force due to the driving force of the electric motor as a service brake and as a parking brake. When the braking force is obtained by the driving force of the electric motor, the braking force is maintained by the self-locking function obtained between the electric motor and the nut member even if the driving force of the electric motor is removed.

  By the way, in the service and parking brake device according to the present invention, an engagement surface formed on the annular flange portion of the screw shaft and facing the bottom wall surface of the cylinder, and formed on the bottom wall surface of the cylinder so that the engagement surface can be rotated. The receiving surfaces to receive are both tapered. In addition, the tapered engagement surface is formed with the outer diameter of the rotating shaft portion as a small diameter and the outer diameter of the annular flange portion as a large diameter. For this reason, a predetermined amount of load transmission area can be secured on the engagement surface of the screw shaft while keeping the outer diameter of the annular flange portion of the screw shaft small.

  Thus, when a predetermined amount of load transmission area is ensured on a plane orthogonal to the cylinder axis (that is, both the engagement surface and the receiving surface are in an annular shape orthogonal to the cylinder axis, and the annular flange portion is Compared to the comparative example, which is an annular flat plate shape perpendicular to the cylinder axis), the load center on the engagement surface can be brought closer to the cylinder axis, and the moment arm of the axial load acting on the annular flange part Can be shortened. For this reason, the axial direction deflection amount (deformation amount) of the annular flange portion with respect to the axial force (axial load) acting on the screw shaft from the piston can be reduced as compared with the comparative example described above.

  Therefore, when the regular and parking brake device is used as a parking brake, both a braking force (axial force) due to hydraulic pressure and a braking force (axial force) due to the driving force of the electric motor can be obtained (high braking force can be obtained). The hydraulic pressure and the driving force of the electric motor are removed and the self-locking state is released, and the piston that the hydraulic pressure has shared is pressed against the axial force acting on the screw shaft by the driving of the electric motor. Even if an axial force is applied, the annular flange portion does not deform more than necessary (bends in the axial direction), and the axial force acting on the screw shaft does not decrease more than necessary.

  Further, in the present invention, although the axial length is increased as compared with the comparative example in which the annular flange portion has a truncated cone shape and the annular flange portion has an annular flat plate shape, the outer diameter thereof is reduced. It is possible to set so as not to increase the weight of the portion (screw shaft). As a result, it is possible to suppress a decrease in brake force due to the axial deflection of the annular flange portion without causing a new problem (increase in the weight of the screw shaft).

  In carrying out the above-described present invention, the seal ring may be assembled in an annular groove formed coaxially in the axially intermediate portion of the insertion hole. In this case, when the tapered receiving surface and the tapered engaging surface are directly joined without using a bearing, the small diameter portion of the receiving surface is set to have substantially the same diameter as the small diameter portion of the engaging surface. When the seal ring is assembled in an annular groove formed coaxially at the hydraulic chamber side end of the insertion hole (in this case, the small diameter portion of the receiving surface is Shorten the moment arm of the axial load acting on the annular flange part (suppress brake force reduction due to axial deflection of the annular flange part) compared to a smaller diameter than the smaller diameter part) Can do.

It is a top view which shows one Embodiment of the regular and parking brake apparatus by this invention. It is sectional drawing along the AA line of the common use parking brake apparatus shown in FIG. It is the B section expanded sectional view of FIG. It is sectional drawing equivalent to FIG. 3 which shows other embodiment of this invention. FIG. 4 is a cross-sectional view corresponding to FIG. 3 illustrating an embodiment in which a tapered receiving surface and a tapered engaging surface are directly joined without a bearing, and (a) is an annular shape in which a seal ring is assembled. It is the figure which showed embodiment in which the groove | channel is coaxially formed in the axial direction intermediate part of an insertion hole, (b) is an annular groove in which a seal ring is assembled | attached, and is coaxial with the liquid chamber side edge part of an insertion hole It is the figure which showed embodiment formed in.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of a service and parking brake device according to the present invention, and a service and parking brake device 100 of this embodiment is an embodiment of the present invention implemented on a movable caliper type disc brake. A cylinder 11 provided in the movable caliper 10, a piston 21 assembled in a cylinder inner hole 11 a of the cylinder 11, and a disk rotor 40 (a braked rotating body that rotates integrally with a wheel (not shown)) by the piston 21. The inner pad 31 is pushed in the cylinder axial direction, and the outer pad 32 is pushed in the cylinder axial direction toward the disc rotor 40 by the reaction force arm portion 12 provided in the movable caliper 10. The common and parking brake device 100 includes a nut member 61, a screw shaft 62, and an electric motor 71 that are assembled to the cylinder 11 and the piston 21.

  The movable caliper 10 has a cylinder 11 and a reaction arm 12, and is supported by being mounted on the mounting 50 so as to be slidable along the rotor axial direction (substantially parallel to the cylinder axial direction). . As is well known, the mounting 50 is formed so as to straddle the disk rotor 40, and the inner pad 31 can be slid along the rotor axial direction by an inner portion 51 disposed inside the disk rotor 40. The outer pad 32 is slidably supported along the rotor axial direction by an outer portion 52 disposed outside the disc rotor 40.

  The cylinder 11 is disposed inside the disk rotor 40 and is formed in a bottomed cylindrical shape. The cylinder 11 has a cylinder inner hole 11a along the rotor axial direction and a bottom wall 11b. The reaction force arm portion 12 is disposed outside the disk rotor 40 and is connected to the cylinder 11 via the bridge portion 13 so that the outer pad 32 can be pushed toward the disk rotor 40 in the rotor axial direction. Has been.

  The piston 21 is movable in a cylinder axial direction through a piston seal 22 in a cylinder inner hole 11a formed in the cylinder 11 of the movable caliper 10 and is fluid-tightly assembled. The cylinder 11 is filled with brake fluid. The hydraulic chamber Ro is formed. The piston 21 is configured not to rotate around the cylinder axis. As is well known, the fluid pressure chamber Ro is connected to a brake fluid pressure circuit (which is a brake fluid supply / discharge device of various forms not shown), and is configured to be able to supply and discharge brake fluid through the brake fluid pressure circuit. Has been. A dust seal 23 is assembled between the rotor side end of the piston 21 and the rotor side end of the cylinder 11.

  The inner pad 31 is composed of a brake lining 31a and a back plate 31b, and can be engaged and disengaged with respect to the disc rotor 40 by the brake lining 31a. It is comprised so that it may be pushed toward a cylinder axial direction toward. On the other hand, the outer pad 32 is constituted by a brake lining 32a and a back plate 32b, and can be engaged / disengaged with respect to the disk rotor 40 by the brake lining 32a. It is configured to be pushed toward the rotor 40 in the cylinder axial direction.

  The nut member 61 is disposed coaxially with respect to the piston 21 in the hydraulic chamber Ro, and is formed on the inner periphery of the piston 21 at an uneven portion that is formed on the outer periphery and extends in the cylinder axial direction. It is fitted to a concavo-convex portion extending in the cylinder axial direction, and is assembled so as not to rotate with respect to the piston 21 and to be movable in the cylinder axial direction. The nut member 61 can be brought into contact with and separated from the piston 21 at the rotor side (brake lining side) end portion, and has a female screw portion 61a at the shaft center portion.

  The screw shaft 62 is arranged coaxially with respect to the piston 21 and has a rotation shaft portion 62a at one side portion (the inner end portion on the left side in FIG. 2) as shown in FIG. The part (the outer end part on the right side in FIG. 2) has a male thread part 62b, and the intermediate part has an annular flange part 62c. The rotary shaft portion 62a is assembled in a liquid-tight manner through a seal ring 63 in an insertion hole 11b1 (see FIG. 3) provided in the bottom wall 11b of the cylinder 11, and rotates about the cylinder axis with respect to the cylinder 11. As shown in FIG. 2, it is prevented from coming off by a clip 64 assembled to a portion of the rotating shaft 62a that protrudes outside the cylinder (restricted in the cylinder axis direction relative to the cylinder 11). Have been). The male screw part 62 b is screwed to the female screw part 61 a of the nut member 61. The annular flange portion 62c is connected to a bottom wall surface 11b2 of the cylinder 11 exposed to the hydraulic chamber Ro via a tapered bearing 65 (for example, a needle bearing that allows the screw shaft 62 to rotate with respect to the cylinder 11). It is rotatably engaged.

  As shown in FIG. 3, the bearing 65 includes a tapered inner race 65 a assembled to the outer periphery of the annular flange portion 62 c of the screw shaft 62, and a tapered outer race assembled to the bottom wall surface 11 b 2 of the cylinder 11. In addition to the race 65b, a rotating body (for example, a needle) and a cage (details omitted) are provided between the inner race 65a and the outer race 65b.

  The electric motor 71 is assembled to the cylinder 11 together with the speed reducer 72, and can rotate the screw shaft 62 in both forward and reverse directions via the speed reducer 72. The operation of the electric motor 71 is controlled by an electric control device (not shown). The speed reducer 72 is spline-fitted to an input shaft (not shown) connected to a rotating shaft (not shown) of the electric motor 71 and an inner spline 62a1 (see FIG. 3) provided on the rotating shaft portion 62a of the screw shaft 62. The output shaft 72a is provided so that the rotation of the rotation shaft of the electric motor 71 can be transmitted to the screw shaft 62 after being decelerated.

  By the way, in this embodiment, as shown in an enlarged manner in FIG. 3, a tapered engagement surface Sa facing the bottom wall surface 11 b 2 of the cylinder 11 is formed on the annular flange portion 62 c of the screw shaft 62. Yes. The tapered engagement surface Sa has a small outer diameter D1 of the rotating shaft portion 62a and a large outer diameter D2 of the annular flange portion 62c. On the other hand, a tapered receiving surface Sb is formed on the bottom wall surface 11b2 of the cylinder 11 so as to rotatably receive the tapered engaging surface Sa via the bearing 65. The tapered receiving surface Sb has a taper angle that is the same as the taper angle of the tapered engagement surface Sa.

  In this embodiment, when the piston 21 is pushed toward the disc rotor 40 in the cylinder axial direction by the positive rotational driving force of the electric motor 71 and a braking force is obtained, the driving force of the electric motor 71 is obtained. Is removed, the self-locking function obtained between the electric motor 71 and the nut member 61 (the function of preventing the piston 21 pushed in the cylinder axial direction from being returned, and the screwing of the nut member 61 and the screw shaft 62). The brake force is maintained by a joint resistance, a rotational resistance obtained by the speed reducer 72, the electric motor 71, and the like. The braking force obtained by the forward rotation driving force of the electric motor 71 can be removed (released) by the reverse rotation driving of the electric motor 71.

  In the service and parking brake device 100 of this embodiment configured as described above, the piston 21 can be advanced and retracted in the cylinder axial direction by supplying and discharging brake fluid to and from the hydraulic chamber Ro. It is possible to obtain a braking force. Further, by driving the screw shaft 62 forward and backward with the electric motor 71, the nut member 61 and the piston 21 can be moved back and forth in the cylinder axis direction, and the braking force is applied by the forward rotation driving force of the electric motor 71. It is possible to obtain.

  Therefore, the brake force generated by the hydraulic pressure and the brake force generated by the driving force of the electric motor 71 can be used as a service brake and can be used as a parking brake. When the braking force by the hydraulic pressure and the braking force by the driving force of the electric motor 71 are obtained and used as a parking brake, the electric motor 71 is used even if the hydraulic pressure and the positive rotational driving force of the electric motor 71 are removed. Thus, the braking force is maintained by the self-locking function obtained between the nut members 61.

  In addition, when using the service and parking brake device 100 as a service brake, it is possible to set so that the brake force by the driving force of the electric motor 71 cannot be obtained and only the brake force by the hydraulic pressure can be obtained. . In addition, when the regular and parking brake device 100 is used as a parking brake, it is possible to set so that the braking force by the hydraulic pressure is not obtained and only the braking force by the driving force of the electric motor 71 is obtained. .

  By the way, in the common and parking brake device 100 of this embodiment, formed on the annular flange portion 62c of the screw shaft 62 and facing the bottom wall surface 11b2 of the cylinder 11 and formed on the bottom wall surface 11b2 of the cylinder 11. The receiving surface Sb that receives the engaging surface Sa in a rotatable manner is both tapered. In addition, the tapered engagement surface Sa is formed with the outer diameter D1 of the rotating shaft portion 62a as a small diameter and the outer diameter D2 of the annular flange portion 62c as a large diameter. For this reason, a predetermined amount of load transmission area can be secured on the engagement surface Sa while the outer diameter D2 of the annular flange portion 62c of the screw shaft 62 is kept small.

  As a result, when a predetermined amount of load transmission area is secured on a plane orthogonal to the cylinder axis Lo (that is, the engagement surface and the reception surface corresponding to the engagement surface Sa and the reception surface Sb are both cylinders). The center of load on the engagement surface Sa is the cylinder axis (cylinder axis) as compared with a comparative example in which the annular flange is an annular flat plate shape orthogonal to the axis and the annular flange is orthogonal to the cylinder axis. Lo), and the moment arm of the axial load acting on the annular flange portion 62c can be shortened. For this reason, as compared with the above-described comparative example, the axial deflection amount (deformation amount) of the annular flange portion 62c with respect to the axial force (axial load) acting on the screw shaft 62 from the piston 21 can be reduced.

  Therefore, when the regular and parking brake device 100 is used as a parking brake, both a braking force (axial force) by hydraulic pressure and a braking force (axial force) by the driving force of the electric motor 71 can be obtained (high braking force). From the state in which the hydraulic pressure and the driving force of the electric motor 71 are removed, the self-locking state is achieved, and the hydraulic pressure is shared by the axial force that has been applied to the screw shaft 62 by the driving of the electric motor 71. Even if an axial force that presses the piston 21 is applied, the annular flange portion 62c is not deformed more than necessary (bends in the axial direction), and the axial force acting on the screw shaft 62 is unnecessarily reduced. There is no.

  Further, in this embodiment, the annular flange portion 62c has a truncated cone shape, and the axial length increases compared to the comparative example in which the annular flange portion has an annular flat plate shape, but its outer diameter decreases. It is possible to set so that the weight of the annular flange portion 62c (screw shaft 62) does not increase. In this embodiment, the bearing 65 is formed in a tapered shape along the tapered engagement surface Sa and the tapered receiving surface Sb, and most of the bearing 65 is an axial dimension of the annular flange portion 62c. Since the axial space required for disposing the bearing 65 is substantially unnecessary, the axial length can be reduced accordingly. As a result, the increase in the axial length of the screw shaft 62 due to the increase in the axial length of the annular flange portion 62c is offset by the reduction in the axial length due to the arrangement of the bearing 65 described above, and the vehicle mounting as the axial length of the screw shaft 62 increases. Without causing new problems such as deterioration in performance and an increase in the weight of the screw shaft 62, it is possible to suppress a reduction in brake force due to the axial deflection of the annular flange portion 62c.

  In the above embodiment, as shown in FIG. 3, the seal ring 63 is configured to be assembled to the annular groove 11b3 formed coaxially at the end of the insertion hole 11b1 on the hydraulic pressure chamber side. However, as shown in FIG. 4, the seal ring 63 may be configured to be assembled to the annular groove 11b3 formed coaxially in the axial direction intermediate portion of the insertion hole 11b1.

  In each of the embodiments described above, as shown in FIGS. 3 and 4, the tapered receiving surface Sb and the tapered engaging surface Sa are indirectly joined via the tapered bearing 65. However, as shown in FIGS. 5A and 5B, the tapered receiving surface Sb and the tapered engaging surface Sa are directly joined without the bearing 65 interposed therebetween. It is also possible to configure and implement as described above.

  In the embodiment shown in FIG. 5A, as in the embodiment shown in FIG. 4, the seal ring 63 is assembled in the annular groove 11b3 formed coaxially in the axially intermediate portion of the insertion hole 11b1. ing. On the other hand, in the embodiment shown in FIG. 5B, similar to the embodiment shown in FIG. 3, the annular groove 11b3 in which the seal ring 63 is coaxially formed at the end portion of the insertion hole 11b1 on the hydraulic pressure chamber side. It is assembled to.

  For this reason, in the embodiment shown in FIG. 5A, the small-diameter portion of the receiving surface Sb can be made substantially the same diameter as the small-diameter portion of the engaging surface Sa, as shown in FIG. Compared to the embodiment (in this embodiment, the small diameter portion of the receiving surface Sb has a larger diameter than the small diameter portion of the engagement surface Sa), the moment arm of the axial load acting on the annular flange portion 62c Can be shortened (the brake force drop due to the axial deflection of the annular flange portion 62c can be suppressed).

  Further, in each of the above-described embodiments, the tapered engagement surface Sa formed on the annular flange portion 62c of the screw shaft 62 and the tapered receiving surface Sb formed on the bottom wall surface 11b2 of the cylinder 11 are: Although the present invention is configured so as to be formed in a tapered shape having a large diameter on the piston 21 side, in implementing the present invention, a tapered engagement surface formed on the annular flange portion of the screw shaft, The taper-shaped receiving surface formed on the bottom wall surface may be configured to be formed in a tapered shape having a small diameter on the piston side.

  In each of the embodiments described above, the present invention is applied to a movable caliper type disc brake. However, the present invention is not limited to a fixed caliper type disc brake, and various drum brakes (a braked rotating body is used as a brake). The brake, which is a drum, can also be carried out in the same manner as in the above-described embodiments or with appropriate modifications.

DESCRIPTION OF SYMBOLS 10 ... Movable caliper, 11 ... Cylinder, 11a ... Cylinder inner hole, 11b ... Cylinder bottom wall, 11b1 ... Insertion hole, 11b2 ... Bottom wall surface, 11b3 ... Annular groove, 21 ... Piston, 31 ... Inner pad, 31a ... Brake lining , 40: Disc rotor (braking body to be braked), 50: Mounting, 61 ... Nut member, 61a ... Female thread part, 62 ... Screw shaft, 62a ... Rotating shaft part, 62b ... Male thread part, 62c ... Annular flange part, 63 ... Seal ring, 65 ... bearing, 71 ... electric motor, 72 ... speed reducer, 100 ... regular and parking brake device, Lo ... cylinder axis, Ro ... hydraulic chamber, Sa ... engagement surface, Sb ... receiving surface

Claims (2)

A cylinder formed in a bottomed cylindrical shape and having a cylinder bore;
A piston that is movable in the cylinder axial direction and is fluid-tightly assembled with respect to the cylinder bore of the cylinder, and that forms a hydraulic chamber in the cylinder;
The piston is pushed by being pushed in the cylinder axial direction 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. ,
It is coaxially arranged with respect to the piston in the hydraulic chamber, is assembled so as not to rotate with respect to the piston and to be movable in the cylinder axial direction, and contacts the piston at the brake lining side end. A nut member that can be contacted / separated and has a female threaded portion in the shaft center;
A rotating shaft that is coaxially arranged with respect to the piston and is assembled in a liquid-tight manner to an insertion hole provided in the bottom wall of the cylinder via a seal ring, and is rotatable about the cylinder axis with respect to the cylinder And a male screw part screwed and connected to the female screw part of the nut member at the other end part, and is rotatable with respect to the bottom wall surface of the cylinder exposed to the hydraulic pressure chamber. A threaded shaft that has an annular flange portion to be engaged at an intermediate portion and is restricted from moving in the cylinder axial direction with respect to the cylinder;
An electric motor mounted on the cylinder and capable of rotating the screw shaft in both forward and reverse directions;
The annular flange portion has a small outer diameter of the rotating shaft portion, a large outer diameter of the annular flange portion, and a tapered engagement surface facing the bottom wall surface of the cylinder is formed.
The bottom wall surface of the cylinder is formed with a taper angle that is the same as the taper angle of the tapered engagement surface, and has a tapered receiving surface that rotatably receives the tapered engagement surface. Formed regular and parking brake device.   2. The service / parking brake device according to claim 1, wherein the seal ring is assembled in an annular groove formed coaxially in an axially intermediate portion of the insertion hole. apparatus.

Images