JP2007218361A - Parking brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parking brake device for producing stable braking force in parking independently of the operating force of a driver or the elongation of a cable. <P>SOLUTION: A drum brake 10 has a rotary drum 13 to be rotated with wheels, and brake shoes 18, 20 arranged to be thrust against the rotary drum 13 for braking the rotary drum 13. It comprises a spring 76 for biasing the brake shoes 18, 29 in their thrusting direction to produce braking force, and an electric motor 78 with a reducer for driving the brake shoes 18, 20 in their non-thrusting direction against the biasing force of the spring 76 to cancel the braking force. The magnitude of the braking force depends on the magnitude of the biasing force of the spring 76 which biases the brake shoes 18, 29 in their thrusting direction. Thus, the wheels are braked with stable braking force which is not influenced by the parking brake operating force of the driver. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a parking brake device, and more particularly to a technique that enables braking of a wheel with a stable braking force that is not affected by a parking brake operation force of a driver or the like.

In a brake device for a vehicle, for example, a drum brake, in general, in a parking brake device for a vehicle, for example, a drum brake having a parking brake function shown in Patent Document 1, the diameter can be expanded to the backing plate and the backing plate. A pair of brake shoes and a parking brake lever that expands the pair of brake shoes against the urging force of the return spring, and the parking brake lever is pulled through a cable. Thus, a braking force at the time of parking can be generated. In addition, as shown in Patent Document 2, it has been proposed that the parking brake lever is tension driven via a cable by an actuator including an electric motor and a speed reducer.
JP 2004-286157 A JP 2002-255017 A

  By the way, in the parking brake device as described above, the parking brake lever is operated by the manual operation force of the driver or by the output of the electric motor by the driver's switch operation, but when the driver is a woman or an elderly person, etc. Since the braking force depends on the operation force of the driver, the braking force at the time of parking may become unstable. In addition, since the cable is stretched or loosened during use, the braking force may become unstable unless it is regularly inspected and adjusted.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to stably obtain a braking force at the time of parking regardless of a driver's operation force or cable extension. An object of the present invention is to provide a parking brake device that can be used.

  The gist of the invention according to claim 1 for achieving this object is a rotating body that rotates together with a wheel, and a braking member that is disposed so as to be able to be pressed against the rotating body in order to brake the rotating body. A parking brake device comprising: a spring that urges the braking member in a pressing direction to generate a braking force; and a spring that resists the urging force of the spring to release the braking force. And an actuator that drives the braking member in the non-pressing direction.

  The gist of the invention according to claim 2 is that, in the invention according to claim 1, (a) the rotating body is a rotating drum that rotates together with the wheels, and (b) the braking member is A pair of arcuate brake shoes disposed on the backing plate so as to be expanded so as to be pressed against the inner peripheral surface of the rotating drum, and (c) the spring is configured to generate the braking force. (D) The actuator is to drive the pair of brake shoes in the diameter-reducing direction against the spring urging force.

  The gist of the invention according to claim 3 is that, in the invention according to claim 2, (a) in order to drive the pair of brake shoes in the non-diameter expanding direction against the urging force of the spring. A parking brake lever rotatably provided on the backing plate, and (b) the spring is stretched between the parking brake lever and the backing plate or a member to which the backing plate is fixed. c) The actuator is to drive the parking brake lever in a direction opposite to the biasing direction by the spring via a cable connected to the parking brake lever.

  According to the parking brake device of the first aspect of the present invention, the parking device includes a rotating body that rotates together with the wheels, and a braking member that is disposed so as to be able to be pressed against the rotating body in order to brake the rotating body. A brake device for biasing the brake member in a pressing direction to generate a braking force, and a non-pressing member against the biasing force of the spring to release the braking force The magnitude of the braking force is determined by the magnitude of the urging force of the spring that urges the braking member in the pressing direction, and is stable without being affected by the parking brake operating force of the driver or the like. The wheel can be braked with the braking force.

  According to the parking brake device of a second aspect of the present invention, the rotating body is a rotating drum that rotates together with the wheel, and the braking member is pressed against the inner peripheral surface of the rotating drum, so that the backing plate A pair of arcuate brake shoes disposed on the upper side so as to be able to expand; and the spring biases the pair of brake shoes in a diameter-enlarging direction to generate a braking force; Is to drive the pair of brake shoes against the spring biasing force in the direction of diameter reduction, so that a drum brake that is normally used can be used in the parking brake device of the present invention. The manufacturing cost of the parking brake device of the present invention can be reduced.

  According to the parking brake device of the invention according to claim 3, the pair of brake shoes are rotatably provided on the backing plate in order to drive the pair of brake shoes against the biasing force of the spring in the non-diameter expansion direction. A parking brake lever, and the spring is stretched between the parking brake lever and the backing plate or a member to which the backing plate is fixed, and the actuator is connected via a cable connected to the parking brake lever. The parking brake lever of the present invention is manufactured by disposing the actuator and the spring on the parking brake lever because the parking brake lever is driven in the direction opposite to the biasing direction by the spring. Can , It can be suitably inexpensive manufacturing cost of the parking brake device of the present invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 shows a hat-type disk and caliper (not shown) of a duo-servo type drum-in-disc brake 12 having a parking brake drum brake (hereinafter referred to as drum brake) 10 according to an embodiment of the present invention in the center. FIG. The hat type disc has a disc-shaped outer peripheral portion and a bottomed cylindrical central portion, the disc-shaped outer peripheral portion functions as a friction plate for a disc brake, and the bottomed cylindrical central portion serves as a rotating drum 13. Configured to work. The rotating drum 13 is represented by two concentric circles indicated by a one-dot chain line in FIG. 1, and the circle on the center side of the drum brake 10 of the two circles is the bottomed cylindrical central portion (the rotating drum 13). The inner peripheral surface 14 of FIG.

  The drum brake 10 has a substantially disc shape, and includes a backing plate 16 that is integrally fixed to a vehicle body side member (non-rotating member) such as an axle tube, an axle housing, and a suspension device (not shown). . A disk cover 17 is secured to the backing plate 16 to protect the disk-shaped outer periphery of the hat type disk.

  The drum brake 10 includes a pair of arc-shaped brake shoes 18 and 20 disposed substantially symmetrically so as to be close to and away from each other in a posture where the convex side is on the outer side of the left and right sides of the backing plate 16, and the pair of brake shoes 18 and 20. The brake shoe widening mechanism 22 provided at a fixed position on the backing plate 16 between one end of the brake shoes 18 and 20, that is, between the upper ends of FIG. 1 and the one end of the pair of brake shoes 18 and 20 approach each other. A return spring 24 stretched between one end portions of the pair of brake shoes 18 and 20 so as to be always urged and brought into contact with the brake shoe expanding mechanism 22, that is, the lower end portion of FIG. A gap adjustment that adjusts the shoe gap by interposing the length of the adjustment wheel 26 to change (elongate) as the adjustment wheel 26 rotates. And a coil stretched between the other ends of the brake shoes 18 and 20 in order to generate an urging force for constantly urging the other end portions in the direction approaching each other and holding the gap adjusting device 28 Shaped spring 30.

  An intermediate portion of the spring 30 is brought into contact with the adjustment wheel 26 of the gap adjusting device 28 so that the adjustment wheel 26 does not rotate due to vibration or the like. Since the gap adjusting device 28 and the spring 30 connect the other end portions of the pair of brake shoes 18 and 20 so as to be relatively rotatable, they function as a connecting device having a gap adjusting function.

  Each of the brake shoes 18, 20 has a flat plate shape substantially parallel to the plate surface of the backing plate 16, and the shoe webs 32, 34, which are entirely curved in an arc shape in the front view shown in FIG. Arc-shaped shoe rims 36 and 38 that are integrally fixed so as to have a substantially T-shaped cross section along the outer peripheral side edge that forms the shape, and the outer peripheral surfaces of the shoe rims 36 and 38 are integrated with an adhesive or the like And linings 40 and 42 made of friction material fixed to each other. The brake shoes 18 and 20 are pressed toward the backing plate 16 by shoe hold-down devices 44 and 46 disposed on the shoe webs 32 and 34, respectively, so that the brake shoes 18 and 20 can move relative to the backing plate 16 in the surface direction. Is retained. The backing plate 16, the shoe webs 32 and 34, and the shoe rims 36 and 38 are all pressed parts that are punched from a steel plate and subjected to predetermined bending.

  2 is an enlarged plan view showing the brake shoe spreading mechanism 22 of the drum brake 10 of the present embodiment. FIGS. 3 to 6 are sectional views taken along line III-III in FIG. 4 is a sectional view taken along line IV-IV, a sectional view taken along line VV in FIG. 2, and a sectional view taken along line VI-VI in FIG.

  2 to 6, the anchor 50 that penetrates the backing plate 16, the disc cover 17, and the reinforcing plate 48 in the thickness direction is fixed by caulking pins 52, 52 and the like. The anchor 50 protrudes on one surface of the mounting portion 50a, a mounting portion 50a that is in close contact with one surface of the backing plate 16, a through portion 50b that penetrates the reinforcing plate 48 and has a tip protruding to the back surface thereof. And a shoe receiving portion 50c. In addition, a through hole 54 that penetrates from the end surface on the penetrating portion 50b side to the end surface on the shoe receiving portion 50c side is provided in the inner peripheral portion. The shoe receiving portion 50c has a stepped cylindrical shape with a smaller diameter at the distal end side than the base side, and the shoe webs 32, 34 of the pair of brake shoes 18, 20 are the outer peripheral surfaces of the small diameter portions, that is, the shoe receiving surfaces 56. Abut. The anchor 50 is for receiving the shoe webs 32 and 34 on the shoe receiving surface 56 during non-braking or braking.

  A T-shaped rod 58 is pierced into the through hole 54, and a slide cam 60 is engaged with one end of the anchor 50 protruding from the shoe receiving portion 50c. In this embodiment, the T-rod 58 and the slide cam 60 constitute a brake shoe spreading mechanism 22 for the brake shoes 18 and 20.

  The T-shaped rod 58 has a T-shape including a shaft portion 58a having a substantially cylindrical shape as a whole, and a guide projection 58b having a rectangular cross section extending along one radial direction at one end thereof. The shaft portion 58a includes a male screw portion 58c at the other end opposite to the guide protrusion 58b, and a lever engaging portion 58d having a rectangular cross section at a portion continuing from the male screw portion 58c to one end side. The part has a slightly larger diameter than the intermediate part. The diameters of both end portions are slightly smaller than the inner diameter of the through hole 54, and are determined so that the shaft portion 58a cannot substantially move in the radial direction in the through hole 54.

  The T-shaped rod 58 is pierced through the through-hole 54 in the shaft portion 58a so as to be rotatable about the axis and not movable in the direction perpendicular thereto, that is, the lower surface of the guide projection 58b, that is, the male screw portion. One surface on the 58c side abuts on the opening end surface 62 on the shoe receiving portion 50c side of the anchor 50, and a part on the other end side of the shaft portion 58a protrudes from the penetrating portion 50b side of the anchor 50. At the protruding end, a spacer 64 having an inner diameter similar to the outer diameter of the shaft portion 58a is positioned substantially at the boundary between the cylindrical portion of the shaft portion 58a and the lever engaging portion 58d. It is attached to. Further, a parking brake lever 68 having a rectangular through-hole 66 corresponding to the lever engaging portion 58d is fitted to the end portion protruding from the spacer 64, and by a nut 70 screwed into the male screw portion 58c. The T-shaped rod 58 is fixed so that it cannot rotate relative to its axis and cannot move in the axial direction.

  The slide cam 60 has a plate-like portion 60a having a shape in which a part of a circular peripheral portion in FIG. 2 is cut by two straight lines that are parallel to each other and symmetrical with respect to the center, and an arc shape remains in the outer peripheral edge. Further, at two positions symmetrical with respect to the center, a pair of leg portions 60b projecting from one surface of the plate-like portion 60a in the vertical direction, that is, on the backing plate 16 side.

  As shown in FIG. 3, the plate-like portion 60a has another portion, that is, an arcuate outer peripheral edge, in the central portion in the direction connecting the midpoints of the pair of arcs on one surface opposite to the leg portion 60b. A rectangular step portion 60d in FIG. 2 that is higher than the neighboring portion 60c is provided, and a guide groove 72 that extends along a direction perpendicular to the direction connecting the midpoints is formed at the center portion of one surface on the leg portion 60b side. It is provided. The guide groove 72 is fitted with the guide projection 58b so as to be relatively movable along the vertical direction, that is, the guide direction, and is slightly smaller than the width dimension and the height dimension of the guide projection 58b. With small width and depth dimensions. Further, the length dimension in the guide direction is sufficiently shorter than the length dimension of the guide protrusion 58b, for example, about 2/3 thereof.

  The pair of leg portions 60b, 60b includes a cam portion 60e extending from one surface of the plate-like portion 60a in the vertical direction, that is, the backing plate 16 side, and an arcuate outer peripheral edge of the plate-like portion 96 from the tip portion of the cam portion 60e. , And a pair of web guide portions 60f, 60f extending in parallel with one surface thereof. The curvatures of the inner peripheral surfaces of the leg portions 60b and 60b are smaller than the curvature of the cylindrical outer peripheral surface of the shoe receiving portion 50c of the anchor 50, respectively. Moreover, the mutual space | interval of the leg parts 60b and 60b is a value slightly larger than the outer diameter of the shoe receiving part 50c. The cam portion 60e has a substantially rectangular cross section as shown in FIG. 2, and the width dimension in the longitudinal direction of the guide groove 72 is the end of the shoe webs 32, 34 of the pair of brake shoes 18, 20 when not braked. It substantially matches the interval between the parts (see FIGS. 2 and 3). Further, the length dimension h of the cam part 60e in the direction from the plate-like part 60a to the web guide part 60f is slightly larger than the thickness dimension t of the shoe webs 32 and 34. As shown in FIG. 3, the web guide portion 60 f may be provided with one surface on the plate-like portion 60 a side parallel to one surface of the plate-like portion 60 a, but as shown in FIGS. 3 and 4. In addition, it is possible that one surface is inclined by decreasing the height dimension toward the tip.

  The slide cam 60 has the guide groove 72 fitted into the guide protrusion 58b of the T-shaped rod 58, and the anchor 50 in a state where the leg portions 60b and 60b are positioned on the outer peripheral side of the small diameter portion of the shoe receiving portion 50c. Is placed on the open end face 62 of the first. Therefore, the slide cam 60 is engaged with the T-shaped rod 58 so as to be relatively movable along the longitudinal direction of the guide groove 72 and not to be relatively rotatable around the axis of the shaft portion 58a. Since the slide cam 60 has its web guide portion 60f positioned below the shoe webs 32, 34, the guide projection 58b of the T-shaped rod 58 is viewed from above, and the web guide portion 60f is viewed from below. The shoe webs 32 and 34 are in an assembled state. Therefore, the slide cam 60 is prevented from falling off by the shoe webs 32 and 34 without separately requiring a fastening device or the like for fastening to the T-shaped rod 58. Further, the movement of the shoe webs 32 and 34 in the direction away from or approaching the backing plate 16 is suppressed by the T-shaped rod 58 and the slide cam 60.

  FIG. 7 is a view showing the back surface of the drum brake 10 of this embodiment. The parking brake lever 68 is punched from a steel plate and formed into a shape as shown in FIG. The parking brake lever 68 includes a rectangular through hole 66 that allows the T-rod 58 and the parking brake lever 68 described above to rotate integrally at one end thereof, and the other end thereof. A direction in which the latch member 74 fixedly connected to a predetermined position on the back surface of the backing plate 16 and the other end portion of the parking brake lever 68 are approached, that is, the other end portion of the parking brake lever 68 is directed to the inner peripheral side of the backing plate 16. A cable 80 that transmits the driving force of a spring latching portion 68a that latches one end of a spring 76 that is constantly biased in the direction of movement to the other end of the parking brake lever 68 and a driving force of an electric motor 78 with a speed reducer that functions as an actuator. And a cable latching portion 68b for latching one end of the cable.

  The reduction gear-equipped electric motor 78 includes, for example, a first reduction gear (not shown) that increases the rotational torque of the electric motor 78a, and the rotation of the increased rotational torque from the cable latching portion 68b to the reduction motor-equipped electric motor 78 side. That is, it is constituted by a two-stage reduction gear including a second reduction gear (not shown) that is converted into a driving force in the direction E of FIG. Further, the driving force of the speed reducer-equipped electric motor 78 is sufficiently larger than the force constantly biased by the spring 76, and is in the opposite direction. The reduction gear-equipped electric motor 78 generates a signal generated by confirming that the shift lever (not shown) is operated to the parking (P) position, and a signal generated by confirming that the parking brake is permitted to operate. If both are detected, both the signal generated by confirming the operation of the shift lever to the parking (P) position and the signal generated by confirming that the parking brake is released are both When detected, it is controlled by an electronic control unit mounted on the vehicle so as to drive.

  The drum brake 10 having the brake shoe spreading mechanism 22 configured as described above is not limited to the parking brake lever 68 when the braking operation of the parking brake is performed, that is, when the electric motor 78 with a speed reducer is not operated. The spring latching portion 68a at the end receives the urging force of the spring 76, and the spring latching portion 68a is moved to the latching member 74 side. The force rotates the T-shaped rod 58 connected to the parking brake lever 68 around its axis, and rotates the slide cam 76 together with the T-shaped rod 58 in the R direction as shown in FIG.

  When the braking operation of the parking brake is released, that is, when the electric motor 78 with a speed reducer is operated, the driving force of the electric motor 78 with a speed reducer is transmitted to the parking brake lever 68 via the cable 80 and is T-shaped. The rod 58 is rotated about its axis, and the slide cam 60 is rotated in the L direction together with the T-shaped rod 58 as shown in FIG. The parking brake lever 68 is provided on the back surface of the backing plate 16 so that the T-rod 58 and the slide cam 60 can rotate in the L direction only to the position shown in FIG. 8, that is, the position where the brake shoes 18 and 20 are not expanded. It is made to contact | abut to the stopper which is protrudingly provided in FIG.

8-10 is a figure explaining the action | operation of the brake shoe expansion mechanism 22, The FIG. 8 is a figure corresponding to the time of the expansion start of the brake shoes 18 and 20 being started. At the time of starting the brake shoe expansion, that is, at the time of parking brake braking operation, the spring latching portion 68a of the parking brake lever 68 is pulled toward the latching member 74 by the urging force of the sprink 76, and the slide cam 60 together with the T-shaped rod 58 moves in the R direction. Is rotated. Therefore, the end portions of the shoe webs 32 and 34 of the brake shoes 18 and 20 are pressed toward the outer peripheral side of the drum brake 10 by the side surfaces of the cam portion 60e, that is, the pressing surfaces 82 and 82, respectively. Are rotated in the directions of arrows P ₁ and P ₂ around the other end (brake shoe expanding device 22 side). That is, it is expanded. At this time, the brake shoes 18 and 20 rotate substantially symmetrically. Note that the pressing surface 82 is provided on the bottom surface of a recess formed between the plate-like portion 60a and the web guide portion 60f, as is apparent from comparison with FIG.

  FIG. 9 shows a stage in which the brake shoes 18 and 20 are being expanded as described above, and in FIG. 9, the brake shoes 18 are pressed against the inner peripheral surface 14 of the rotating drum. . If the T-shaped rod 58 is further rotated in the R direction from this state, the brake shoe 20 is not yet in contact with the rotary drum inner peripheral surface 14 and thus is rotated to the outer peripheral side. The brake shoe 18 pressed against 14 cannot rotate.

For this reason, the reaction force that the slide cam 60 receives from the brake shoes 18, 20 is relatively large when the slide cam 60 acts on the brake shoe 18, so that the slide cam 60 receives a large reaction force from the brake shoe 18 on the pressing surface 82. In response to this, the T-shaped rod 58 is moved in the arrow S direction while rotating in the R direction. As described above, the slide cam 60 is fitted to the guide protrusion 58b of the T-shaped rod 58 in the guide groove 72 so as to be relatively movable in the longitudinal direction. It is slid with respect to the character rod 58. Accordingly, only the brake shoe 20 is rotated in the direction of the arrow P ₁ while the brake shoe 18 remains in the illustrated position. That is, the brake shoe spreading mechanism 22 of this embodiment is made to follow the difference in shoe clearance between the brake shoes 18 and 20, that is, uneven wear, without the T-shaped rod 58, which is the rotation shaft, swinging at all. As is clear from FIG. 8, the longitudinal direction of the guide groove 72 of the slide cam 58, that is, the guide direction is a direction intersecting the pressing surfaces 82, 82, for example, a direction perpendicular thereto.

  FIG. 10 shows a stage where the expansion is completed by the brake shoe 20 being pressed against the inner peripheral surface 14 of the rotary drum 13. In FIG. 10, the brake shoe 18 stays at the same position as the stage shown in FIG. 9, but the slide cam 60 is rotated toward the brake shoe 20 along the longitudinal direction of the guide groove 72, that is, the guide direction. Since the brake shoe 20 is pressed toward the outer peripheral side by the pressing surface 82 by being moved, it can be seen that the brake shoe 20 is further rotated than the stage shown in FIG. When the rotational force is transmitted to the rotary drum 13 in this state, the end portion on the anchor 50 side of the brake shoe 18 and the shoe receiving surface 56 of the shoe receiving portion 50c come into contact with each other, and a braking force is generated in the drum brake 10.

  When the parking brake is released, that is, when the brake shoes 18 and 20 are reduced in diameter, the T-rod 58 and the slide cam 60 resist the rotation in the R direction by the urging force of the spring 76 by the operation of the electric motor 78 with a speed reducer. When the brake shoes 18 and 20 are reduced in diameter by the urging force of the return spring 24, the braking force of the drum brake 10 is released. Although the actual shoe gap is extremely small and the rotation angle is slight, in FIGS. 8 to 10, the rotation angle is exaggerated for convenience of illustration.

  The above-described operation is for the case where the shoe gaps of the pair of brake shoes 18 and 20 are different. When the shoe gaps are the same, the pressing surfaces 82 and 82 of the slide cam 60 are used for the pair of brake shoes. The pair of brake shoes 18 and 20 are simultaneously pressed against the inner peripheral surface 14 of the rotary drum 13 while receiving the reaction force of the same magnitude from the shoes 18 and 20. Therefore, in this case, relative movement of the slide cam 60 with respect to the T-shaped rod 58 does not occur.

  Here, according to the drum brake 10 of the present embodiment, the rotating drum 13 that rotates together with the wheels, and the brake shoes 18 and 20 that are disposed so as to be able to press against the rotating drum 13 in order to brake the rotating drum 13, A brake 76 for urging the brake shoes 18 and 20 in a pressing direction to generate a braking force, and a biasing force of the spring 76 for releasing the braking force. And a reduction gear electric motor 78 that drives the brake shoes 18 and 20 in the non-pressing direction. Therefore, the magnitude of the braking force is determined by the spring 76 that urges the brake shoes 18 and 20 in the pressing direction. Depends on the magnitude of the urging force, the wheel can be braked with a stable braking force that is not affected by the driver's parking brake operating force.

  The drum brake 10 according to the present embodiment includes a pair of arc-shaped brake shoes 18 and 20 that are disposed on the backing plate 16 so as to be expanded so as to be pressed against the inner peripheral surface 14 of the rotary drum 13. The spring 76 urges the pair of brake shoes 18 and 20 in the diameter expanding direction to generate a braking force, and the electric motor 78 with a speed reducer is attached to the spring 76 to release the braking force. Since the pair of brake shoes 18 and 20 are driven in the diameter-reducing direction against the force, a drum brake that is normally used can be used for the drum brake 10 of the present invention. The manufacturing cost of 10 can be reduced.

  Further, according to the drum brake 10 of the present embodiment, the pair of brake shoes 18 and 20 can be rotated to the backing plate 16 in order to drive the pair of brake shoes 18 and 20 in the non-diameter expansion direction against the urging force of the spring 76. A parking brake lever 68 provided, and the spring 76 is stretched between the parking brake lever 68 and the backing plate 16 or a member to which the backing plate 16 is fixed. Since the parking brake lever 68 is driven in a direction opposite to the biasing direction by the spring 76 via a cable 80 connected to the parking brake lever 68, an electric motor with a speed reducer is connected to the parking brake lever 68. 78 and spring 76 are provided to For a drum brake 10 can be manufactured, it is possible to suitably the manufacturing cost of the drum brake 10 of the present embodiment.

  Next, another embodiment of the present invention will be described. In the following embodiments, portions common to the above-described embodiments are denoted by the same reference numerals and description thereof is omitted.

  FIG. 11 shows a duo servo having a parking brake drum brake (hereinafter referred to as a drum brake) 92 that is substantially the same as the above-described embodiment except that a brake shoe spreading mechanism 90 different from the above-described embodiment is provided. FIG. 12 is an enlarged view of a brake shoe spreading mechanism 90 of the drum brake 92, and FIG. 13 is a sectional view taken along line XIII-XIII of FIG.

  As shown in FIG. 12, the brake shoe spreading mechanism 90 is disposed in parallel so as to substantially overlap each other, and is connected to a parking brake lever 96 and a strut connected to each other by a connecting pin 94 so as to be relatively rotatable. 98, and the connecting pin 94 straddles the pair of brake shoes 18, 20 in a posture that is substantially parallel to the backing plate 16 and in a substantially vertical direction, that is, a posture in which the parking brake lever 96 and the strut 98 are substantially horizontal. It is arranged. The strut 98 is composed of a long metal plate, and is connected to the parking brake lever 96 at the intermediate portion so as to intersect the parking brake lever 96 at a right angle in a plan view shown in FIG. And an engaging portion 98a engaged with the brake shoe 18 is provided. Both ends of the strut 98 are bent in a crank shape so as to be positioned in substantially the same plane as the parking brake lever 96, and are brought into contact with the heads of the pair of bolts 100, whereby the bolt 100 And a pair of brake shoes 18, 20. Further, the strut 98 is provided with a cut-and-raised portion 98b, and is engaged with the parking brake lever 96 to thereby define a turning range of the parking brake lever 96 in the return direction.

  The parking brake lever 96 is also made of a long metal plate, and has an engaging portion 96a that is engaged with the brake shoe 20 at one end thereof, and in the vicinity of the one end thereof, While being connected to the strut 98 by the connecting pin 94, the other end, that is, the tip, protrudes from the insertion hole 104 provided in the anchor block 102, the backing plate 16, the disc cover 17, the reinforcing plate 48, etc. to the vehicle body side. Further, the front end portion thereof is a hooking member fixed by a cable hooking portion 96b for hooking the cable 106 for transmitting the driving force of the electric motor 78 with a speed reducer not shown in FIG. The cable hooking portion 96b of the parking brake lever 96 hooked on the brake shoe 18 is connected to the brake shoe 18 side. And a spring hook portion 96c for engaging a spring 110 for normally urging the F direction in FIG. 13. Further, a cylindrical elastic body, specifically, a rubber lever boot 112 is disposed between the parking brake lever 96 and the backing plate 16, and is inserted while allowing the parking brake lever 96 to rotate. The gap between the holes 104 is closed.

  Since the electric motor 78 with a speed reducer is not operated during parking brake braking by an electronic control unit mounted in the vehicle, the spring hooking portion 96c of the parking brake lever 96 is brake brake shoe by the urging force of the spring 106. When pulled in the direction of the arrow F in FIG. 13, that is, in the direction of arrow F in FIG. 13 and rotated around the brake shoe 18 with reference to the axis of the connecting pin 94, the brake shoe 20 is rotated by the engaging portion 96 a of the parking brake lever 96. 13 is pressed against the inner peripheral surface 14 to generate a braking force. At the same time, when the connecting pin 94 is moved to the brake shoe 18 side by the reaction force with the engaging portion 96b as a fulcrum, the strut 98 is also moved to the brake shoe 18 side, and the brake shoe 18 is moved by the engaging portion 98a of the strut 98. Is pressed to the outside, that is, the lining 40 side, and is pressed against the inner peripheral surface 14 of the rotary drum 13 to generate a braking force.

  When the parking brake braking operation is released, the cable hooking portion 96b of the parking brake lever 96 is pulled in the direction of the brake shoe 20 side, that is, in the arrow G direction in FIG. When the connecting pin 94 is rotated about the axis of the brake shoe 20 as a reference, the brake shoe 20 is pushed toward the brake shoe 18 by the urging force of the return spring 24, and from the inner peripheral surface 14 of the rotary drum 13. Since the brake shoes 18 and 20 are separated from each other, the braking force is released.

  As mentioned above, although the Example of this invention was described based on drawing, this invention is applied also in another aspect.

  For example, the parking brake device of the present invention uses the drum brake 10 in the above-described embodiment, but there is no problem even if it is a disc brake.

  The drum brake 10 of the above-described embodiment is configured to have a duo servo type drum brake. However, other types such as a leading trailing type and a two leading type drum brake may be used. There is no problem.

  Further, one end of each of the springs 76 and 110 of the above-described embodiment is hooked on the hooking members 74 and 108, but there is no problem even if it is hooked directly on the backing plate 16.

  Further, the actuator of the present invention uses the electric motor which is the electric motor 78 with a speed reducer in the above-described embodiment. However, the actuator may be operated by an electromagnet, an air cylinder, a hydraulic cylinder or the like.

  Although not illustrated one by one, the present invention can be implemented in variously modified and improved modes based on the knowledge of those skilled in the art.

It is a figure which shows the drum brake which functions as a brake device for parking which is one Example of this invention. It is a figure explaining the brake shoe expansion mechanism of the drum brake of the Example of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. FIG. 4 is a sectional view taken along line IV-IV in FIG. 1. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 2. FIG. 6 is a sectional view taken along line VI-VI in FIG. 2. It is a figure which shows the back surface in FIG. It is a figure which shows the time of the brake shoe expansion start by a brake shoe expansion mechanism. It is a figure which shows the stage in the expansion process in which one side of the brake shoe was pressed on the rotating drum inner peripheral surface. It is a figure which shows the step which the expansion was complete | finished when a brake shoe was pressed on the internal peripheral surface of a rotating drum. It is a figure which shows the drum brake which functions as a brake device for parking which is the other Example of this invention. It is the figure which expanded the brake shoe expansion mechanism of the drum brake of the Example of FIG. FIG. 13 is a sectional view taken along line XIII-XIII in FIG. 12.

Explanation of symbols

10: Drum brake 13: Rotating drum (rotating body)
14: Inner peripheral surface 16: Backing plate 18, 20: Brake shoe (braking member)
68, 96: Parking brake lever 76, 110: Spring 78: Electric motor with reduction gear (actuator)
80, 106: Cable

Claims (3)

A parking brake device comprising: a rotating body that rotates together with a wheel; and a braking member that is disposed so as to be able to be pressed against the rotating body in order to brake the rotating body,
A spring for urging the braking member in the pressing direction to generate a braking force;
An actuator for driving the braking member in a non-pressing direction against an urging force of the spring in order to release the braking force. The rotating body is a rotating drum that rotates together with the wheel,
The braking member is a pair of arcuate brake shoes disposed on the backing plate so as to be expanded so as to be pressed against the inner peripheral surface of the rotating drum,
The spring urges the pair of brake shoes in the diameter increasing direction to generate a braking force,
2. The parking brake device according to claim 1, wherein the actuator drives the pair of brake shoes in a diameter reducing direction against the spring biasing force. 3. A parking brake lever rotatably provided on the backing plate for driving the pair of brake shoes in a non-diameter expanding direction against the urging force of the spring;
The spring is stretched between the parking brake lever and the backing plate or a member to which the backing plate is fixed,
The parking brake device according to claim 2, wherein the actuator drives the parking brake lever in a direction opposite to a biasing direction by the spring via a cable connected to the parking brake lever.

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