JP2018135989A - Drum brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drum brake device having a parking brake mechanism which enables a large lever ratio of a lever for opening a pair of brake shoes and enables a reduction of force for rotating the lever.SOLUTION: A drum brake device 100 includes: first and second brake shoes 17, 19 which are disposed on a surface parallel to a backing plate 11 so as to be able to be opened while facing an inner peripheral surface of a brake drum with a brake center axis interposed therebetween; a pressing open mechanism 35 having a lever 49 which causes a pressing mechanism disposed between one side ends of first and second webs 23, 25 to operate and thereby open the first and second brake shoes 17, 19. The drum brake device 100 has a parking brake mechanism 33 in which a rotation base part 51 of the lever 49 is disposed near the first brake shoe 17 and a lever input part 53 is disposed near the second brake shoe 19.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a drum brake device.

2. Description of the Related Art A drum brake device that electrically performs shoe extension operation of a parking brake mechanism is known (for example, see Patent Document 1).
As shown in FIG. 13, this type of drum brake device 500 includes a backing plate 501 and the proximity of one end side along the arc of the first web 507 and the second web 509 in the first brake shoe 503 and the second brake shoe 505. The first claw part 511 and the second claw part 513 come into contact with the ends, respectively, and a first pressing member 515 and a second pressing member 517 extending from the rotation base part 519 rotatably supported by the first pressing member 515. The lever input unit 521 is disposed between the second web 509 and the backing plate 501, and a tensile force is applied to the parking cable 523 connected to the lever input unit 521 to rotate the rotation base 519, thereby rotating the rotation base 519. A parking lever 529 that the protruding pressing portion 525 presses the pressed portion 527 of the second pressing member 517; Provided. According to this drum brake device 500, when the parking lever 529 in the parking brake mechanism is arranged in a cross-pull type, the parking lever 529 is stored in the backing plate 501, so that the backing plate lead-out portion 531 of the parking cable 523 can be provided. The structure can be easily laid out.

JP2015-152126A

  However, since the conventional drum brake device 500 stores the parking lever 529 in the backing plate 501, the lever itself is set small. Further, in order to suppress the variation in lever ratio, the lever ratio is set to be lower than the forward pull type (small lever ratio). For this reason, as shown in FIG. 13, the parking lever 529 is disposed between the backing plate 501 and the second web 509 and between the back plate 533 of the second brake shoe 505 and the rotational axis 535 of the wheel. Has been. That is, the parking lever 529 is arranged in a radial region centered on the rotation axis 535. As a result, the lever pulling force increases with respect to the forward pull type, and the reaction force input to the backing plate 501 increases. For this reason, the backing plate 501 needs to have high strength, and a large drive mechanism (motor gear unit) is required when the parking brake mechanism is electrified.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a drum having a parking brake mechanism that can increase a lever ratio of a lever that expands a pair of brake shoes and can reduce a force for rotating the lever. It is to provide a brake device.

The above object of the present invention is achieved by the following configuration.
(1) A pair of brake shoes disposed opposite to the inner peripheral surface of the brake drum so as to be spreadable on a surface parallel to the backing plate, and disposed between one end of the web in the pair of brake shoes. A pressing and expanding mechanism having a lever for operating the pressing mechanism to expand the pair of brake shoes, and a rotating base portion of the lever is disposed in the vicinity of one of the brake shoes and extends from the rotating base portion A drum brake device having a parking brake mechanism in which a lever input portion is disposed in the vicinity of the other brake shoe.

  According to the drum brake device having the above configuration (1), the rotation base portion of the lever in the pressing and expanding mechanism is disposed in the vicinity of one brake shoe, and the lever input portion is disposed in the vicinity of the other brake shoe. Therefore, the lever itself can be lengthened, and the distance from the rotation base to the lever input portion can be increased, so that the lever ratio can be increased.

(2) The drum brake device according to (1), wherein the lever input portion is disposed between the web positioned on the side opposite to the rotation base and the backing plate.

  According to the drum brake device having the configuration of (2) above, the lever input portion is disposed between the web and the backing plate located on the opposite side of the rotation base portion, so that the lever is connected to the inner edge of the web. Interference is avoided. Therefore, the lever from which the interference with the inner edge portion is avoided can move outward in the radial direction from the wheel rotation axis side. Accordingly, the drive position of the drive member connected to the lever input portion of the lever can also be moved radially outward from the rotation axis side of the wheel, so that the drive member can be easily laid out. As a result, a drive mechanism such as a motor gear unit connected to the drive member can also move radially outward from the wheel rotation axis side, and interference with other members is less likely to occur. Further, the lever itself can be further lengthened, and the distance from the rotation base portion to the lever input portion can be further increased, so that the lever ratio can be further increased.

(3) The pressing and expanding mechanism includes a first pressing member and a second pressing member disposed between a pair of the webs, and the lever is rotatably supported by the first pressing member. The lever input portion is disposed between the web and the backing plate on the second pressing member side, and an external force is applied to the lever input portion to rotate the rotation base portion, whereby the lever The drum brake device according to (1) or (2), wherein the lever pressing portion presses the second pressing member to expand the pair of brake shoes.

  According to the drum brake device having the configuration (3), the first pressing member and the second pressing member are arranged between the pair of webs. The lever has a rotating base supported by the first pressing member. The lever to which the external force is input to the lever input portion rotates around the rotation base supported by the first pressing member, and the lever pressing portion presses the second pressing member in a direction away from the first pressing member. Accordingly, the first pressing member and the second pressing member are separated from each other, and the pair of brake shoes that are in contact with both ends thereof are expanded. Here, the lever input part of the lever is disposed between the web and the backing plate on the second pressing member side. Further, the rotation base portion of the lever is disposed on the opposite side of the lever input portion with the brake center axis interposed therebetween. As a result, the lever that is configured to be large while avoiding interference with other members can be arranged between the web and the backing plate at high density (without making useless space).

(4) The pressing and expanding mechanism includes a pressing member disposed between a pair of the webs and a lever pressing portion of the lever, and the rotating base is rotatably supported by the pressing member on the lever. In addition, the lever input portion is disposed between the web and the backing plate on the opposite side of the lever pressing portion, and an external force is applied to the lever input portion to rotate the rotating base portion, whereby the lever pressing portion The drum brake device according to (1) or (2), in which the web on the lever pressing portion side is pressed to expand the pair of brake shoes.

  According to the drum brake device having the configuration (4), the pressing member is disposed between the pair of webs. The rotating base is rotatably supported by the lever in the vicinity of the pressing mechanism that comes into contact with one of the webs. The lever has a lever pressing portion in the vicinity of the rotation base. Further, the lever input portion is arranged on the opposite side of the lever pressing portion with the brake center axis interposed therebetween. In the lever, a lever pressing portion in the vicinity of the rotation base comes into contact with one web. When an external force is applied to the lever input portion and the rotation base portion is rotated, the lever pressing portion directly presses one of the webs to expand the pair of brake shoes. Here, as described above, in the lever, the lever input portion is disposed between the other web and the backing plate, and the rotation base portion is disposed on the opposite side of the lever input portion with the brake central axis interposed therebetween. As a result, the lever can be arranged at a high density (without making useless space) while avoiding interference with other members.

(5) The drum brake device according to any one of (1) to (4), wherein the pressing and expanding mechanism includes an adjuster for automatically adjusting a shoe interval.

  According to the drum brake device having the above configuration (5), when the amount of movement of the pair of brake shoes during braking increases due to wear of the brake shoes, the overall length of the adjuster automatically increases. As a result, the standby positions of the pair of brake shoes during non-braking are separated. As a result, the total size of the pair of shoe gaps on both sides is maintained substantially constant.

(6) The said lever input part is connected with respect to the drive member which applies external force to the said lever input part so that a movement to the expansion direction of a pair of brake shoe which cross | intersects a drive direction is said (1)-( The drum brake device according to any one of 5).

  According to the drum brake device having the above configuration (6), the drive member and the lever are connected (surface contact) movable in the expanding direction of the pair of brake shoes. Thereby, the change in the standby position when the pair of brake shoes automatically adjusted by the adjuster is not braked and the displacement of the lever when the lining is worn can be absorbed by the sliding of the contact surface. Therefore, it is not necessary to arrange a short cable or a clevis for connecting the driving member and the lever.

(7) The drum brake device according to (6), wherein the driving member is driven by a motor gear unit.

  According to the drum brake device having the above configuration (7), the drive member is pulled by driving the motor gear unit, and the lever rotation external force can be input to the lever input portion by the pulled drive member, and the parking brake can be electrically driven. It becomes.

(8) The drum brake according to any one of (1) to (7), wherein the lever is disposed between a wheel cylinder for expanding the pair of brake shoes and the pressing mechanism. apparatus.

  According to the drum brake device having the configuration (8), the lever is disposed between the wheel cylinder and the pressing mechanism. Therefore, the vicinity space secured by arranging the wheel cylinder can be effectively used. This makes it difficult for the lever to interfere with the unevenness of the mounting portion of the vehicle, and it is easy to ensure a lever stroke when the lever rotates.

  According to the drum brake device having the parking brake mechanism according to the present invention, the lever ratio for expanding the pair of brake shoes can be increased, and the force for rotating the lever can be reduced.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

1 is a front view of a drum brake device according to a first embodiment of the present invention. It is AA sectional drawing of FIG. It is the perspective view which abbreviate | omitted the wheel cylinder of the drum brake apparatus shown in FIG. FIG. 4 is a perspective view of a press spreading mechanism shown in FIG. 3. It is a disassembled perspective view of the press expansion mechanism shown in FIG. It is a front view of the drum brake device concerning a 2nd embodiment of the present invention. It is BB sectional drawing of FIG. It is a perspective view of the drum brake device shown in FIG. It is a perspective view of the press expansion mechanism shown in FIG. It is a disassembled perspective view of the press expansion mechanism shown in FIG. It is a front view of the drum brake device concerning a 3rd embodiment of the present invention. It is CC sectional drawing of FIG. It is principal part sectional drawing of the conventional drum brake device.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
As shown in FIGS. 1 to 3, the drum brake device 100 according to the first embodiment of the present invention is integrally fixed to the vehicle body in a posture in which the backing plate 11 is substantially perpendicular to the wheel rotation axis 13. Is done. The backing plate 11 is formed with a predetermined strength by raising an outer peripheral edge of a circular substrate made of a thick metal plate as a peripheral wall. As shown in FIG. 2, a motor gear unit 15 for electrifying the parking brake is provided on the surface of the backing plate 11 on the vehicle side. A pair of first brake shoes 17 and second brake shoes 19 each having an arc shape are disposed on the backing plate 11 along the outer peripheral edge on the vehicle front-rear direction side (left-right direction side in FIG. 1).

  The first brake shoe 17 and the second brake shoe 19 disposed on the backing plate 11 have a first web 23 (see FIG. 2) and a second web 25 fixed to the inner peripheral side of the back plate 21, respectively. A lining 27 is fixed to the outer peripheral side of 21. The first web 23 and the second web 25 are opposed to each other across a diameter of a virtual circle (not shown) centered on the wheel rotation axis 13 perpendicular to the backing plate 11, and are arcuate on a plane parallel to the backing plate 11. Is formed. In the present specification, an extension line of the above-described diameter sandwiched between the first web 23 and the second web 25 is referred to as a brake center shaft 29 (see FIG. 1).

  Each of the first brake shoe 17 and the second brake shoe 19 is held by the shoe hold-down device 31 so as to be spreadable on the backing plate 11. The first brake shoe 17 and the second brake shoe 19 are disposed so as to be able to expand on a plane parallel to the backing plate 11 so as to face the inner peripheral surface of the brake drum 30 with the brake center shaft 29 interposed therebetween.

  As shown in FIG. 1, between one end of the first brake shoe 17 and the second brake shoe 19 (specifically, between the upper end portions in FIG. 1), The return spring 37 is disposed substantially horizontally. On the other hand, between the other ends of the first brake shoe 17 and the second brake shoe 19 (specifically, between the lower ends of FIG. 1), the first brake shoe 17 and the first brake shoe 17 are fixed to the backing plate 11. An anchor portion 39 with which the other end portion of the second brake shoe 19 abuts and a tension coil spring 41 are disposed substantially horizontally.

  Further, a wheel cylinder 43 is interposed between one end portions of the first brake shoe 17 and the second brake shoe 19 on the upper side in FIG. The wheel cylinder 43 is attached to the backing plate 11, and the first piston 42 and the second piston 44 push the one end portion away from each other to expand the first brake shoe 17 and the second brake shoe 19. Let The wheel cylinder 43 moves the first brake shoe 17 and the second brake shoe 19 around the contact point with the anchor portion 39 by the first piston 42 and the second piston 44 that advance from both ends during service braking by depressing the foot brake pedal. Rotate to open. The first brake shoe 17 and the second brake shoe 19 that have been rotated in an expanded manner are frictionally engaged with the inner peripheral surface of the brake drum 30 to brake it.

  That is, the drum brake device 100 according to the present embodiment has a leading trailing structure in which the upper portion opens with the lower anchor portion 39 as a fulcrum.

2 is a cross-sectional view taken along the line AA in FIG.
The parking brake mechanism 33 includes the above-described pressing and expanding mechanism 35 and a driving member 45 driven by the motor gear unit 15. The pressing and expanding mechanism 35 includes a pressing mechanism 47 and a lever 49. The pressing mechanism 47 is disposed between one ends of the first web 23 and the second web 25. The lever 49 operates the pressing mechanism 47 to expand the first brake shoe 17 and the second brake shoe 19.

FIG. 3 is a perspective view in which the wheel cylinder 43 of the drum brake device shown in FIG. 1 is omitted.
In the pressing and expanding mechanism 35 of the parking brake mechanism 33, the rotation base 51 of the lever 49 is arranged in the vicinity of one first brake shoe 17, and the lever input portion 53 extending from the rotation base 51 is the other second brake shoe. 19 is arranged in the vicinity. Moreover, the lever input part 53 is arrange | positioned between the 2nd web 25 located on the opposite side to the rotation base 51, and the backing plate 11 (refer FIG. 2).

  In the drum brake device 100, the lever 49 is disposed between the wheel cylinder 43 and the pressing mechanism 47 for expanding the pair of first brake shoes 17 and second brake shoes 19.

4 is a perspective view of the pressing and expanding mechanism 35 shown in FIG. 3, and FIG. 5 is an exploded perspective view of the pressing and expanding mechanism 35 shown in FIG.
More specifically, the pressing mechanism 47 of the present embodiment includes a first pressing member 55 and a second pressing member 57 that are disposed between the first web 23 and the second web 25. In the lever 49, the rotation base 51 is rotatably supported by the first pressing member 55 via a lever pin 59. The lever pin 59 has a head, an insertion tip opposite to the head penetrates the first pressing member 55 and the rotation base 51, and a retaining ring 61 is attached to the penetration tip to prevent dropping.

  The lever 49 has the lever input portion 53 disposed between the second web 25 and the backing plate 11 on the second pressing member 57 side. In the lever 49, an external force is applied to the lever input portion 53 to rotate the rotation base 51, so that the lever pressing portion 63 (see FIG. 5) of the lever 49 presses the second pressing member 57 and the first brake shoe. 17 and the second brake shoe 19 are expanded.

  In the drum brake device 100 according to the present embodiment, the drive member 45 is driven by the motor gear unit 15. The drive member 45 applies an external force to the lever input portion 53.

  As shown in FIGS. 4 and 5, the driving member 45 is formed in a rectangular box shape having a lever insertion opening 65. The lever 49 is connected to the driving member 45 in an engaged state when the lever input portion 53 is inserted into the lever insertion opening 65 with play. In other words, the lever input portion 53 is directed toward the drive member 45 that applies an external force to the lever input portion 53 in the direction in which the pair of first brake shoes 17 and second brake shoes 19 are expanded (arrow a in FIG. 4). (Contact point with the drive member 45 is movable). Therefore, the outer periphery of the tip of the lever input portion 53 is formed in an arc shape (see FIG. 2) centering on the center line in the same direction as the lever pin 59. The contact between the lever input portion 53 and the drive member 45 moves on the outer periphery of the arc shape.

  Further, in the drum brake device 100 according to the present embodiment, the pressing and expanding mechanism 35 includes an adjuster 67 (see FIG. 1) for automatically adjusting the shoe interval. The adjuster 67 has an adjuster socket 69, an adjuster gear 71, an adjuster nut 73, and an adjuster lever 75 (see FIG. 1). The adjuster 67 adjusts the shoe interval between the first brake shoe 17 and the second brake shoe 19. The adjuster 67 constitutes a part of the pressing mechanism 47.

  The adjuster gear 71 extends the entire length of the adjuster 67 by rotation to make the brake shoe interval constant. One end of the adjuster gear 71 is screwed into the adjuster nut 73, the other end is fitted and inserted into the adjuster socket 69, and a toothed ring 77 is formed at the intermediate portion. The adjuster lever 75 has a claw portion 79 (see FIG. 1) that faces the toothed wheel 77, and the timepiece shown in FIG. 1 is centered on the adjuster pin 81 when the first brake shoe 17 and the second brake shoe 19 are expanded. The claw portion 79 is configured to come into contact with the toothed ring 77 by rotating in the rotating direction.

  In the automatic adjustment of the shoe interval by the adjuster 67, the return spring 37 always applies a force that rotates the adjuster lever 75 about the adjuster pin 81 in the clockwise direction in FIG. When the wear amount of the lining 27 increases, the first brake shoe 17 and the second brake shoe 19 move more than the specified stroke, and when the rotation amount of the adjuster lever 75 exceeds the specified amount, the claw portion 79 becomes a toothed wheel. 77, the toothed ring 77 is rotated by one tooth. Accordingly, the adjuster 67 automatically adjusts the shoe gap by extending. The adjuster 67 increases the overall length, thereby separating the standby positions of the first brake shoe 17 and the second brake shoe 19 during non-braking and maintaining the shoe gap (the total size of the shoe gaps on both sides) substantially constant. To do.

  In the adjuster socket 69, the opposite side of the gear fitting hole 83 into which the adjuster gear 71 is inserted is a web engaging claw 85 that engages with the first web 23. The adjuster nut 73 has a lever / pressing portion engaging claw 89 engaged with the first pressing member 55 and the lever pressing portion 63 on the opposite side of the gear screwing portion 87 to which the adjuster gear 71 is screwed. The first pressing member 55 has a nut engaging portion 91 that engages with the lever / pressing portion engaging claw 89, and the web engaging claw 93 that engages the second web 25 on the opposite side of the nut engaging portion 91. It becomes.

Next, the operation of the above configuration will be described.
In the drum brake device 100 according to the first embodiment, the rotation base 51 of the lever 49 in the pressing and expanding mechanism 35 is disposed in the vicinity of the first brake shoe 17, and the lever input portion 53 is disposed in the vicinity of the second brake shoe 19. The Therefore, the lever itself can be lengthened, and the distance from the rotation base 51 to the lever input portion 53 can be increased, so that the lever ratio can be increased.
Further, since the lever input portion 53 is disposed between the second web 25 and the backing plate 11 located on the side opposite to the rotation base 51, the lever 49 interferes with the inner edge of the second web 25. Is avoided. Therefore, the lever 49 from which the interference with the inner edge portion is avoided can move outward in the radial direction from the wheel rotation axis 13 side. Accordingly, the drive position of the drive member 45 connected to the lever input portion 53 of the lever 49 can also be moved radially outward from the wheel rotation axis 13 side, so that the drive member 45 can be easily laid out. As a result, the motor gear unit 15 connected to the drive member 45 can also move radially outward from the wheel rotation axis 13 side, and interference with other members such as a brake mounting portion (hub) of the vehicle is less likely to occur. Become. Further, the lever 49 itself can be further lengthened, and the distance from the rotation base 51 to the lever input portion 53 can be further increased, so that the lever ratio can be further increased.

  In the drum brake device 100 according to the first embodiment, the first pressing member 55 and the second pressing member 57 are disposed between the pair of the first web 23 and the second web 25. In the lever 49, the rotation base 51 is supported by the first pressing member 55. The lever 49 to which an external force is input to the lever input portion 53 rotates around the rotation base 51 supported by the first pressing member 55, and the lever pressing portion 63 separates the second pressing member 57 from the first pressing member 55. Press in the direction to do. Accordingly, the first pressing member 55 and the second pressing member 57 are separated from each other, and the pair of the first brake shoes 17 and the second brake shoes 19 that are in contact with both ends thereof are expanded. Here, as shown in FIG. 2, in the lever 49, the lever input portion 53 is disposed between the second web 25 and the backing plate 11 on the second pressing member side. The rotation base 51 of the lever 49 is disposed on the opposite side of the lever input portion 53 with the brake center shaft 29 interposed therebetween. As a result, the lever 49, which is configured to be large while avoiding interference with other members, has a high density between the first web 23 and the second web 25 and the backing plate 11 (without leaving a useless space). Can be arranged.

  In the drum brake device 100 according to the first embodiment, when the movement amount of the pair of first brake shoes 17 and second brake shoes 19 during braking increases due to wear of the brake shoes, the overall length of the adjuster 67 is automatically increased. Become longer. Thereby, the standby positions of the pair of first brake shoes 17 and second brake shoes 19 at the time of non-braking are separated. As a result, the total size of the pair of shoe gaps on both sides is maintained substantially constant.

  Further, in the drum brake device 100 according to the first embodiment, the drive member 45 and the lever 49 are connected to each other so that the pair of first brake shoes 17 and second brake shoes 19 can move in the expanding direction (surface contact). Has been. As a result, the contact surface slides when the standby position of the pair of first brake shoe 17 and second brake shoe 19 automatically adjusted by the adjuster 67 is changed during non-braking and the lever 49 is displaced when the lining 27 is worn. Can be absorbed. Therefore, it is not necessary to arrange a short cable or a clevis for connecting the driving member 45 and the lever 49.

  In the drum brake device 100 according to the first embodiment, the driving member 45 is pulled by driving the motor gear unit 15, and a rotating external force can be input to the lever input unit 53 by the pulled driving member 45, thereby Electrification can be easily realized.

  Further, in the drum brake device 100 according to the first embodiment, a lever 49 is disposed between the wheel cylinder 43 and the pressing mechanism 47. Therefore, the vicinity space secured by disposing the wheel cylinder 43 can be used effectively. This makes it difficult for the lever 49 to interfere with the unevenness of the mounting portion of the vehicle, and it is easy to ensure a lever stroke when the lever 49 rotates.

[Second Embodiment]
As shown in FIGS. 6 to 8, the drum brake device 200 according to the second embodiment of the present invention, except for the parking brake mechanism 95, includes a backing plate 11, an anchor portion 39, a motor gear unit 15, a drive member 45, The wheel cylinder 43, the return spring 37, and the tension coil spring 41 are configured in substantially the same manner as the drum brake device 100 according to the first embodiment. Therefore, in the following description, the parking brake mechanism 95 will be mainly described in detail, and description of other configurations of the drum brake device 200 that is equivalent to the drum brake device 100 will be omitted.

  As shown in FIG. 7, the parking brake mechanism 95 includes a pressing and expanding mechanism 97 and a driving member 45 driven by the motor gear unit 15. The pressing and expanding mechanism 97 includes a pressing mechanism 99 (see FIG. 9) and a lever 101. The pressing mechanism 99 is disposed between one ends of the first web 23 and the second web 25. The lever 101 operates the pressing mechanism 99 to expand the first brake shoe 17 and the second brake shoe 19.

  In the pressing and expanding mechanism 97 of the second embodiment, as in the first embodiment, the rotation base 51 of the lever 101 is disposed in the vicinity of the first brake shoe 17, and the lever extends from the rotation base 51. The input unit 53 is disposed in the vicinity of the other second brake shoe 19.

9 is a perspective view of the pressing and expanding mechanism 97 shown in FIG. 8, and FIG. 10 is an exploded perspective view of the pressing and expanding mechanism 97 shown in FIG.
More specifically, the pressing mechanism 99 of the present embodiment has a pressing member 105 disposed between the first web 23 and the second web 25. The lever 101 is rotatably supported by the support member 103 of the pressing member 105 via the lever pin 59. The lever pin 59 has a head, the insertion tip opposite to the head penetrates through the support member 103 and the rotation base 51, and a retaining ring 61 is attached to the penetration tip to prevent dropping.

  The lever 101 has a protruding lever pressing portion 107 shown in FIG. 7 on the outer periphery in the vicinity of the rotation base 51. The lever pressing portion 107 directly contacts the inner peripheral end surface of the first web 23 in the first brake shoe 17. The lever 101 is disposed between the second web 25 and the backing plate 11 on the side opposite to the lever pressing portion 107 with respect to the lever input portion 53. In the lever 101, an external force is applied to the lever input portion 53 to rotate the rotation base 51, so that the lever pressing portion 107 of the lever 101 presses the first web 23 on the lever pressing portion side and the first brake shoe 17. And the second brake shoe 19 is expanded.

  In the drum brake device 200 according to the present embodiment, the pressing and expanding mechanism 97 has an adjuster 109 (see FIG. 6) for automatically adjusting the shoe interval. The adjuster 109 includes an adjuster socket 111, an adjuster gear 71, an adjuster nut 113, and an adjuster lever 75 (see FIG. 6). The adjuster 109 adjusts the shoe interval between the first brake shoe 17 and the second brake shoe 19. The adjuster 109 constitutes a part of the pressing mechanism 99.

  The adjuster gear 71 extends the entire length of the adjuster 109 by rotation to make the brake shoe interval constant. One end of the adjuster gear 71 is screwed into the adjuster nut 113, and the other end is fitted and inserted into the adjuster socket 111, and a toothed ring 77 is formed at an intermediate portion. The adjuster lever 75 has a claw portion 79 (see FIG. 6) that faces the toothed wheel 77, and the timepiece shown in FIG. 6 is centered on the adjuster pin 81 when the first brake shoe 17 and the second brake shoe 19 are expanded. The claw portion 79 is configured to come into contact with the toothed ring 77 by rotating in the rotating direction.

  In the shoe interval automatic adjustment operation by the adjuster 109, as with the adjuster 67 described above, when the wear amount of the lining 27 increases, the first brake shoe 17 and the second brake shoe 19 move more than a specified stroke, and accordingly the adjuster lever. When the rotation amount of 75 exceeds the specified amount, the adjuster 109 extends to automatically adjust the shoe gap. The adjuster 109 increases the overall length, thereby separating the standby positions of the first brake shoe 17 and the second brake shoe 19 during non-braking and maintaining the shoe gap (the total size of the shoe gaps on both sides) substantially constant. To do.

  In the adjuster socket 111, the opposite side of the gear fitting hole 83 into which the adjuster gear 71 is inserted is a web engaging claw 115 that engages with the second web 25. The adjuster nut 113 is integrally fixed to the support member 103 on the opposite side of the gear screwing portion 87 into which the adjuster gear 71 is screwed. In the support member 103, the opposite side of the adjuster nut 113 is a web engaging claw 117 that engages with the first web 23.

Next, the operation of the above configuration will be described.
In the drum brake device 200 according to the second embodiment, the pressing member 105 is disposed between the first web 23 and the second web 25. In the lever 101, the rotation base 51 is rotatably supported via a lever pin 59 on a portion (support member 103) in the vicinity of the pressing mechanism 99 that contacts one of the first webs 23. The lever 101 has a lever pressing portion 107 in the vicinity of the rotation base 51.

  The lever input portion 53 is disposed on the opposite side of the lever pressing portion 107 with the brake center shaft 29 interposed therebetween. In the lever 101, the lever pressing portion 107 in the vicinity of the rotation base abuts on the first web 23. When an external force is applied to the lever input portion 53 and the rotation base 51 is rotated, the lever pressing portion 107 directly presses one of the first webs 23 to expand the first brake shoe 17 and the second brake shoe 19. .

  Here, in the lever 101, the lever input portion 53 is disposed between the second web 25 and the backing plate 11, and the rotation base 51 is disposed on the opposite side of the lever input portion 53 with the brake center shaft 29 interposed therebetween. As a result, the lever 101 can be arranged at a high density (without making useless space) while avoiding interference with other members.

[Third Embodiment]
As shown in FIGS. 11 and 12, the drum brake device 300 according to the third embodiment of the present invention, except for the parking brake mechanism 207 and the auto adjuster (shoe gap automatic adjusting mechanism) 221, includes the backing plate 11 and the anchor portion. 39, the motor gear unit 15, the drive member 45, the wheel cylinder 43, the return spring 37, the tension coil spring 41, and the like are configured in substantially the same manner as the drum brake device 200 according to the second embodiment. Therefore, in the following description, the parking brake mechanism 207 and the auto adjuster 221 will be mainly described in detail, and description of other configurations of the drum brake device 300 equivalent to the drum brake device 200 will be omitted.

  As shown in FIG. 11, the parking brake mechanism 207 includes a pressing and expanding mechanism 205 and a driving member 45 driven by the motor gear unit 15. The pressing and expanding mechanism 205 includes a pressing mechanism 203 (see FIG. 12) and a lever 201. The pressing mechanism 203 is disposed between one ends of the first web 23 and the second web 25. The lever 201 operates the pressing mechanism 203 to expand the first brake shoe 17 and the second brake shoe 19.

  More specifically, the pressing mechanism 203 according to the third embodiment includes a pressing member 209 disposed between the first web 23 and the second web 25. The lever 201 is rotatably supported at the end of the pressing member 209 on the first brake shoe 17 side via a lever pin 59. The lever pin 59 has a head, an insertion tip opposite to the head penetrates the pressing member 209 and the rotation base 51, and a retaining ring 61 is attached to the penetration tip, so that dropping is restricted.

  The lever 201 has a protruding lever pressing portion 107 shown in FIG. 12 on the outer periphery in the vicinity of the rotation base 51. The lever pressing portion 107 directly contacts the inner peripheral end surface of the first web 23 in the first brake shoe 17. The lever 201 is disposed in the vicinity of the second web 25 where the lever input portion 53 is on the side opposite to the lever pressing portion 107. In the lever 201, an external force is applied to the lever input portion 53 and the rotation base 51 is rotated, so that the lever pressing portion 107 of the lever 201 presses the first web 23 on the lever pressing portion side and the first brake shoe 17. And the second brake shoe 19 is expanded.

  That is, also in the pressing and expanding mechanism 205 of the third embodiment, the rotation base 51 of the lever 201 is disposed in the vicinity of the first brake shoe 17 and extends from the rotation base 51, as in the second embodiment. The lever input part 53 to be taken out is disposed in the vicinity of the other second brake shoe 19 with the brake center shaft 29 interposed therebetween.

  Further, the lever input portion 53 that extends in parallel with the backing plate 11 from the rotation base 51 and is disposed in the vicinity of the second brake shoe 19 is disposed on the inner side of the second web 25 on the second brake shoe 19 side. ing. The lever insertion opening 65 of the drive member 45 is disposed on the opposite side of the backing plate 11 with respect to the second web 25.

  Furthermore, in the drum brake device 300 according to the third embodiment, an auto adjuster 221 that adjusts the shoe interval is provided between adjacent ends of the first brake shoe 17 and the second brake shoe 19 in the vicinity of the wheel cylinder 43. A pressing member 209 is interposed (see FIG. 12). The pressing member 209 is moved to the inside of the first brake shoe 17 following the rotation of the lever 201.

  The auto adjuster 221 is a shoe gap automatic adjustment mechanism, and defines the standby positions of the first brake shoe 17 and the second brake shoe 19 during non-braking. The auto adjuster 221 includes a guide plate 225 fixed to the second web 25 of the second brake shoe 19, a wedge-shaped plate 223 interposed between one end 209 a of the pressing member 209 and the guide plate 225, and a wedge-shaped plate A tension coil spring 227 that biases 223 toward the other adjacent end of the second brake shoe 19 and a tension coil spring 229 that biases the pressing member 209 toward the guide plate 225 are configured.

  The auto adjuster 221 changes the standby positions of the first brake shoe 17 and the second brake shoe 19 according to the wear of the friction material. That is, when the amount of movement of the first brake shoe 17 and the second brake shoe 19 during braking increases due to wear of the friction material, the guide plate 225 fixed to the second brake shoe 19 is pressed via the wedge-shaped plate 223. The gap between the one end 209a of the pressing member 209 and the guide plate 225 is widened, the standby positions of the first brake shoe 17 and the second brake shoe 19 are separated during non-braking, and the shoe gap (the sum of the shoe gaps on both sides) Dimension) is maintained substantially constant.

Next, the operation of the above configuration will be described.
In the drum brake device 300 according to the third embodiment, the rotation base 51 of the lever 201 rotatably supported at the end of the pressing member 209 on the first brake shoe 17 side is disposed in the vicinity of the first brake shoe 17. The lever input portion 53 is disposed in the vicinity of the second brake shoe 19. Therefore, the lever itself can be lengthened, and the distance from the rotation base 51 to the lever input portion 53 can be increased, so that the lever ratio can be increased.
The lever input portion 53 is disposed on the inner side of the second web 25 on the second brake shoe 19 side, and the lever insertion opening 65 of the drive member 45 is on the opposite side of the backing plate 11 with respect to the second web 25. Is arranged. Therefore, the lever input portion 53 can secure a sufficient clearance between the backing plate 11 and the stroke amount of the lever 201 can be increased.

  Therefore, according to the drum brake devices 100, 200, and 300 having the parking brake mechanisms 33, 95, and 207 according to the above-described embodiments, the levers 49 and 101 for expanding the pair of first and second brake shoes 17 and 19 are expanded. , 201 can be increased, and the force for rotating the levers 49, 101, 201 can be reduced.

  The present invention is not limited to the above-described embodiments, and the configurations of the embodiments may be combined with each other, or may be modified or applied by those skilled in the art based on the description of the specification and well-known techniques. The invention is intended and is within the scope of seeking protection.

  For example, in the above configuration example, the case where the parking brake mechanism is electrically driven by the motor gear unit 15 has been described. However, the configuration of the present invention has the same effect as described above even when applied to a manual parking brake mechanism.

11 ... backing plate 15 ... motor gear unit 17 ... first brake shoe (one brake shoe)
19 ... Second brake shoe (the other brake shoe)
23. First web (web)
25. Second web (web)
29 ... Brake center shaft 33 ... Parking brake mechanism 35 ... Press expanding mechanism 43 ... Wheel cylinder 45 ... Drive member 47 ... Pressing mechanism 49 ... Lever 51 ... Rotating base 53 ... Lever input part 55 ... First pressing member 57 ... Second Press member 63 ... Lever pressing portion 67 ... Adjuster 100 ... Drum brake device

Claims (8)

A pair of brake shoes disposed so as to be able to expand on a surface parallel to the backing plate facing the inner peripheral surface of the brake drum;
A pressing and expanding mechanism having a lever that operates a pressing mechanism disposed between one ends of the webs of the pair of brake shoes to expand the pair of brake shoes;
A drum brake device having a parking brake mechanism in which a rotation base portion of the lever is disposed in the vicinity of one brake shoe, and a lever input portion extending from the rotation base is disposed in the vicinity of the other brake shoe.   2. The drum brake device according to claim 1, wherein the lever input portion is disposed between the web located on the opposite side of the rotation base and the backing plate. The pressing and expanding mechanism includes a first pressing member and a second pressing member disposed between the pair of webs,
The lever is rotatably supported by the first pressing member, and the lever input portion is disposed between the web and the backing plate on the second pressing member side. 3. The drum brake according to claim 1, wherein when the external base is applied and the rotation base is rotated, the lever pressing portion of the lever presses the second pressing member to expand the pair of brake shoes. apparatus. The pressing and expanding mechanism includes a pressing member disposed between a pair of the webs and a lever pressing portion of the lever.
The lever is rotatably supported by the pressing member, and the lever input portion is disposed between the web and the backing plate on the opposite side of the lever pressing portion, and an external force is applied to the lever input portion. The drum brake according to claim 1, wherein the lever pressing portion presses the web on the lever pressing portion side to expand the pair of brake shoes by rotating the rotating base portion. apparatus.   The drum brake device according to any one of claims 1 to 4, wherein the pressing and expanding mechanism includes an adjuster for automatically adjusting a shoe interval.   The lever input portion is connected to a drive member that applies an external force to the lever input portion so as to be movable in an expanding direction of the pair of brake shoes that intersects the driving direction. The drum brake device according to item.   The drum brake device according to claim 6, wherein the driving member is driven by a motor gear unit.   The drum brake device according to any one of claims 1 to 7, wherein the lever is disposed between a wheel cylinder for expanding the pair of brake shoes and the pressing mechanism.

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