JP2005133911A - Cable guide of drum brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cable guide capable of properly preventing a brake cable from displacing and dropping off before assembling. <P>SOLUTION: A cable supporting part consisting of a supporting part 70, a side wall part 72 and a facing part 74 is structured so that a cable 8 can get in and out through an open part 82. As a protrusion 80 for preventing drop from the open part 82 is provided at a side of the cable 8 in a position a predetermined distance apart from the cable supporting part, displacement and drop of the brake cable 8 before assembling a drum brake 4 is restricted. As a gap through which the cable 8 can pass is provided between the cable supporting part and the protrusion 80, the cable can be easily inserted in and taken from the cable supporting part through the gap while preventing drop and the like by the protrusion 80, assembling properties are not hindered at all. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cable guide for inserting a brake cable for generating a braking force in a drum brake into and out of the drum brake.

  A drum brake in which a brake shoe disposed on a backing plate is mechanically pressed against a rotating drum by a brake cable to generate a braking force is used for a vehicle parking brake or the like. There is also a drum-in-disc brake in which a similar drum brake is incorporated in a hat portion of a brake disc to constitute a vehicle parking brake. In such a drum brake, the brake cable is introduced into the drum brake from behind the backing plate through an insertion hole provided in the backing plate, and is fixed at a predetermined position by a cable guide attached to the backing plate. At the same time, its tip is engaged with a parking brake lever (see, for example, Patent Document 1).

  6 is a plan view showing an example of the cable guide 100 assembled to the drum brake, FIG. 7 is a sectional view taken along the line VII-VII, and FIG. 8 is a sectional view taken along the line VIII-VIII. The cable guide 100 is a metal plate that has been pressed or punched, and is attached to a backing plate 106 at flat fixing portions 102 and 104, and a guide portion 108 provided above them. The brake cable (inner wire) 110 is guided in a predetermined direction. A long hole 112 is provided at a substantially central portion of the fixing portion 104, and the brake cable 110 is inserted into the long hole 112 from the back surface (the lower surface in the drawing) of the backing plate 106 to enter the inside of the drum brake. be introduced. In addition, the guide portion 108 includes side walls 114 and 114 formed by bending both side edges in the width direction upward, and has a substantially U shape or a substantially semicircular shape according to the outer shape of the brake cable 110. The cross section is made.

The brake cable 110 is disposed substantially parallel to the backing plate 106 and is connected to a brake lever (not shown). When the tensile force is applied, the brake cable 110 is rotated to generate a braking force. A return spring 116 for returning the brake lever to its original position is disposed substantially concentrically, and one end thereof is seated on the guide portion 108 of the cable guide 100. The guide portion 108 has a smaller opening width at the fixed portion 102 side than at the fixed portion 104 side, and holds the brake cable 110 at the narrow portion, and the end portion of the return spring 116 at the wide portion. Is housed.
Japanese Utility Model Publication No. 5-62748

  By the way, the brake cable 110 is engaged or attached at one end to the brake lever, a part at the other end to the back surface of the backing plate 106, and the like, and an intermediate portion thereof is supported by the cable guide 100 in the brake drum. By applying a predetermined tension, the drum brake is fixed at a predetermined position. However, since the intermediate portion is merely fitted into the U-shaped portion of the guide portion 108, it can be easily detached from the intermediate portion when appropriate tension is not applied. For this reason, before installation where sufficient tension is not applied to the brake cable 110, the brake cable 110 may fall off or be displaced from the guide portion 108 due to the weight of the loose brake cable 110 or contact of a human hand. There was a problem that the assembly workability deteriorated.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cable guide that can suitably prevent displacement and dropping of a brake cable before assembly.

  In order to achieve this object, the gist of the present invention is that a brake shoe disposed on the backing plate is mechanically pressed against the rotating drum when a tensile force is applied to the brake cable to generate a braking force. A cable guide that is integrally fixed to the backing plate, supports the brake cable with a predetermined tension, and allows the brake cable to be inserted into and out of the drum brake, (a) the brake cable A cable holding portion surrounding an outer peripheral surface of a predetermined range in the longitudinal direction of the brake cable so that a part of the brake cable in the circumferential direction is opened by an opening portion having an opening width dimension larger than the diameter; and (b) the brake cable A side of the brake cable separated from the cable holding part by a predetermined distance along the longitudinal direction. The brake cable accommodated in the cable holding portion is prevented from escaping from the open portion, and a gap through which the brake cable can pass in the radial direction is formed between the brake cable and the cable holding portion. And an escape prevention part.

  In this way, the cable holding portion is configured such that the brake cable in which the predetermined range in the longitudinal direction is accommodated can be entered and exited through the opening portion, but the brake cable at a position separated from the cable holding portion by a predetermined distance is used. Since the side is provided with an escape prevention part that suppresses the escape of the brake cable from the open part, it is preferable that the brake cable is displaced on the cable guide or dropped even before the drum brake is assembled. It is suppressed. At this time, since a gap through which the brake cable can pass in the radial direction is provided between the cable holding portion and the escape prevention portion, the brake cable is positioned on the side when the brake cable is kept straight. By curving the brake cable while restraining the brake cable from dropping or the like with the escape restraining portion, the cable restraining portion can be easily entered and exited through the gap between the cable retaining portion and the escape restraining portion. The “side of the brake cable” is a position at which the escape restraining part can restrain the brake cable from being released from the open part. For example, when the cable holding part has a U-shape, the brake part is braked from the open part. The position is a predetermined distance away from the cable holder along the longitudinal direction of the cable.

  Here, preferably, the cable holding portion includes a support portion that includes a support surface that presses the brake cable in a direction away from the backing plate, and a counter portion that includes a counter surface facing the support surface. And a U-shaped cross section having a connecting portion for connecting the supporting portion and the facing portion at their end portions. In this way, since the escape restraining part can project from one of the support part and the opposing part toward the other, the cable holding part is provided with an opening part on the side opposite to the backing plate. In comparison, the escape prevention portion can be easily formed.

  In the case where the cable holding portion has a U-shaped cross section as described above, preferably, the escape restraining portion is arranged at an end portion of the opposing portion opposite to the connecting portion of the brake cable. It is a protrusion that suppresses the escape of the cable at its distal end by protruding in a direction that is inclined along the longitudinal direction and toward the support section, and the position of the support section that faces the protrusion is the facing position. The stepped shape is made lower than the position facing the part. In this way, it is possible to easily form the escape prevention part simply by bending the tip part of the facing part, and the brake cable is suitably prevented from dropping or misaligned by the tip part of the projection, and the brake cable is held. Alternatively, when the brake cable is removed, the brake cable can be easily inserted / extracted from the gap between the protrusion and the support portion by bending the brake cable upward (that is, on the side opposite to the backing plate in the assembled state of the drum brake).

  Further, when the cable holding part has a U-shaped cross section as described above, the escape prevention part is preferably a projecting piece projecting from the support part in a direction away from the backing plate. In this way, it is possible to easily form the escape restraining part simply by bending a part of the support part, and the dropping or misalignment of the brake cable is suitably restrained by the protruding piece, At the time of detachment, the brake cable can be easily inserted / extracted from the gap between the projecting piece and the support portion by bending the brake cable so as to protrude downward (that is, on the backing plate side in the assembled state of the drum brake).

  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 is a schematic configuration diagram showing a parking brake device 2 for a vehicle to which the present invention is applied. The leading / trailing drum brake 4 is disposed near a wheel, and is disposed near a driver's seat. Operation lever 6 and a brake cable 8 connecting them, and when the operation lever 6 is pulled up, a tensile force is applied to the brake cable 8 and the drum brake 4 is mechanically operated. The braking force is applied to a wheel (not shown).

  The drum brake 4 is used as a parking brake and a service brake, and includes a backing plate 10 fixed to a vehicle body side member that rotatably supports a wheel. A pair of brake shoes 12, 14 having an arc shape are provided so as to be able to expand each other by shoe hold-down devices 16, 18. The backing plate 10 is mainly composed of a disk-shaped flat surface portion parallel to a reference plane (a plane parallel to the paper surface of FIG. 1) of the drum brake 4 where the pair of brake shoes 12 and 14 approach and separate from each other. One end portions (upper end portions) of the pair of brake shoes 12 and 14 are respectively engaged with both end portions of the wheel cylinder 26 fixed to the backing plate 10, and serve as brakes for the service brake, that is, service brake operation members. When the brake pedal is depressed, the wheel cylinders 26 are expanded in the direction of being separated from each other, and are pressed by the rotating drum 27 that rotates together with the wheels to generate a braking force. In the vicinity of the wheel cylinder 26 and on the inner peripheral side of the backing plate 10, a return spring (a tension coil spring in the embodiment) 28 is stretched across the brake shoes 12 and 14 and approaches each other. The struts 30 are disposed so as to pass through the inside of the return spring 28, and the approach positions (standby) of the pair of brake shoes 12 and 14 that are made to approach according to the urging force of the return spring 28 during non-braking. Position) is defined. The other end portions (lower end portions) of the brake shoes 12 and 14 are in contact with the anchors 32 fixed to the backing plate 10.

  A brake lever 34 is attached to the end of one brake shoe 12 on the wheel cylinder 26 side so as to be rotatable about the axis of a mounting shaft 36 that is substantially perpendicular to the backing plate 10. The brake lever 34 and the other brake shoe 14 are disposed over the brake lever 34. The brake cable 8 is connected to the tip (lower end) of the brake lever 34, and when the operation lever 6 is operated and the brake cable 8 is pulled rightward in FIG. 1, the brake lever 34 is attached to the mounting shaft 36. When the brake shoe 14 is rotated counterclockwise and moved to the right via the strut 30, the brake shoe 12 is pressed by the rotating drum 27 to generate a braking force, and the brake shoe 12 together with the mounting shaft 36 is reacted. It is moved leftward and pressed by the rotating drum 27 to generate a braking force. When the parking brake is not operated, the brake lever 34 is held at a fixed original position where the engagement protrusion 34 a abuts against the shoe rim of the brake shoe 12 by the action of the return springs 28 and 38, and the brake shoe 12 is interposed via the brake lever 34. The approach position is defined by the strut 30. The strut 30 is extended by the action of a screw when an adjuster wheel 40 provided at an intermediate portion is rotated in one direction by a shoe gap automatic adjusting mechanism 42, and a pair of brakes when not braked. The approach positions of the shoes 12 and 14 are separated from each other, so that the shoe gap between the brake shoes 12 and 14 and the rotating drum 27 (the sum of both) is maintained substantially constant regardless of the wear of the lining. Yes.

  The brake cable 8 includes a first cable 50 connected to the brake lever 34 and a second cable 52 connected to the operation lever 6, and the first cable 50 and the second cable 52 thereof. Are integrally connected by a cable connector 54 in the vicinity of the drum brake 4. The first cable 50 is inserted through a cable guide 56 provided on the backing plate 10 and extends to the back side (outside) of the backing plate 10 without an outer casing, while the second cable 52 is an outer casing (not shown). The inside of the drum brake 4 is guided to the vicinity of the drum brake 4. Before assembling the drum brake 4 to the vehicle, the other end of the first cable 50 is connected to the brake lever 34 in a state where the connecting side end extends from the cable guide 56 to the back side, and the drum brake 4 is assembled to the vehicle. Later, it is connected to the second cable 52 via the cable connector 54. The first cable 50 is coated with nylon.

  2 is a plan view showing an example of the cable guide 56, and FIG. 3 is a sectional view taken along line III-III in FIG. The cable guide 56 is formed by pressing or punching a metal plate. The cable guide 56 is attached to the backing plate 10 at flat fixing portions 58 and 60, and at a guide portion 62 provided above them. The cable 8 is guided in a predetermined direction. The fixing portion 58 has a substantially rhombus shape, and one corner on the fixing portion 60 side is bent upward at an angle of, for example, about 60 to 80 °. A long hole 66 through which the cable 8 is pierced is provided at a substantially central portion of the fixing portion 58, and a flat surface portion constituting the main body of the backing plate 10 is provided on both sides in the short diameter direction of the long hole 66. Round holes 68 and 68 for fixing are provided. On the other hand, the fixing portion 60 has a substantially rectangular shape, and one side on the fixing portion 58 side is bent upward, for example, at a substantially right angle.

  The guide portion 62 is formed between the portions bent upward of the fixing portions 58 and 60, and the tip height positions of the bent portions are different from each other as shown in FIG. For example, the fixed portion 60 side is lower by a size substantially equal to the wire diameter of the return spring 38, for example. The step formed in this portion is provided to receive the left end portion of the return spring 38 in the drawing. Further, the cable 8 is pushed up in a direction away from the backing plate 10 by being supported by the support portion 70 at a relatively high position in the guide portion 62.

  Further, the guide portion 62 is formed at the intermediate portion in the longitudinal direction of the cable 8 by being bent at a substantially right angle from one side along the cable 8 (one side on the upper side in FIG. 2) upward in FIG. The side wall portion 72 is erected and restricts the upward movement of the cable 8 supported by the support portion 70 in FIG. A part (for example, substantially half) of the side wall portion 72 on the fixed portion 58 side has a facing portion 74 extending horizontally from the upper end of the side wall toward the other side of the guide portion 62 above the cable 8. One surface (opposing surface) 78 is formed to face the flat support surface 76 of 70. Therefore, the guide portion 62 is provided with a U-shaped cable holding portion constituted by the support portion 70, the side wall portion 72, and the facing portion 74, and the cable 8 has the U-shaped open portion 82. It is accommodated in the cable holding part in a state where it can enter and exit only. In other words, the cable guide 56 is provided with an opening 82 between the support portion 70 and the facing portion 74 that opens a part in the circumferential direction with an opening width dimension larger than the diameter of the cable 8. In the present embodiment, the side wall portion 72 corresponds to the connecting portion.

  Further, the facing portion 74 has a length dimension in the direction from one side to the other side of the guide portion 62 on the fixed portion 60 side that is longer than that on the fixed portion 58 side, and the tip thereof is more than the support portion 70. Is also projected downward in FIG. The protruding portion is provided with a protrusion 80 protruding toward the fixed portion 60 at a position outside the return spring 38. As shown in FIG. 3, the protrusion 80 is inclined downward so as to approach the backing plate 10 toward the tip, and the tip is separated from the end surface of the facing portion 74 on the fixed portion 60 side by a predetermined distance. At the side of the cable 8. The distal end portion of the protrusion 80 is positioned above the spring receiving portion 84 that is relatively lower than the support portion 70 in the guide portion 62, and the cable 8 is between the protrusion 80 and the spring receiving portion 84. A gap sufficiently larger than the diameter is formed. Since the protrusion 80 protrudes from a position outside the return spring 38, the protrusion 80 is positioned adjacent to the cable 8 and the return spring 38 without interfering with the cable 8 and the return spring 38.

  The cable guide 56 thus configured is configured so that the opening 82 of the cable holding portion is larger in opening width than the diameter of the cable 8 (the vertical dimension in FIG. 3) so that the cable 8 can enter and exit. However, the cable 8 is prevented from entering and exiting while being kept straight by a protrusion 80 having a distal end positioned on the side thereof. However, since a gap having a size that allows the cable 8 to enter and exit is formed between the protrusion 80 and the spring receiving portion 84, the cable 8 can be bent slightly and passed through the gap. That is, the tip of the protrusion 80 is located on the side of the cable 8 at a position slightly separated from the cable holding portion toward the fixing portion 60, and the spring receiving portion 84 having a height lower than that of the support portion 70 is located at that position. Since it is formed, the cable 8 can be moved in and out despite the protrusions 80 being provided. The bending angle of the protrusion 80 and the tip position thereof are determined so that the cable 8 can easily enter and exit. In the present embodiment, the protrusion 80 corresponds to the escape prevention portion.

  In short, according to the present embodiment, the cable holding portion constituted by the support portion 70, the side wall portion 72, and the facing portion 74 allows the cable 8 in which a part in the longitudinal direction is accommodated to enter and exit through the opening portion 82. Although it is configured, a protrusion 80 is provided on the side of the cable 8 at a position spaced apart from the cable holding portion by a predetermined distance so as to prevent escape from the opening portion 82. In this case, the brake cable 8 is preferably prevented from being displaced or dropped on the cable guide 56. At this time, since a gap through which the cable 8 can pass in the radial direction is provided between the cable holding portion and the protrusion 80, the protrusion 80 can prevent the cable 8 from dropping and the like. Since it can be easily bent into and out of the cable holding portion through the gap, the assembling property is not hindered.

  FIGS. 4 and 5 are views corresponding to FIGS. 2 and 3 for explaining a cable guide 86 according to another embodiment of the present invention. In these drawings, the cable guide 86 is configured in the same manner as the cable guide 56 except that a guide portion 88 is different from the guide portion 62. The guide portion 88 extends in the same manner as the cable guide 56 from the support portion 70 and the side wall portion 72, and the fixing portion 58 side end of the side wall 72 toward the other side of the support portion 70, that is, the lower side in FIG. The cable holding part which consists of the opposing part 90 is provided. The facing portion 90 has a substantially rectangular shape, and its tip is located above the vicinity of the other side of the support portion 70. Also in the present embodiment, a cable holding portion in which the shape of the facing portion 90 is slightly different from the facing portion 74 is constituted by the support portion 70, the side wall 72, and the facing portion 90.

  Further, in the vicinity of the fixed portion 60 side of the cable holding portion, a projecting piece 92 is provided extending from the side opposite to the side wall portion 72 of the spring receiving portion 84 to the upper side in FIG. It has been. A gap sufficiently larger than the diameter of the cable 8 is formed between the tip (upper end) of the projecting piece 92 and the facing portion 90. Therefore, also in this embodiment, the brake cable 8 is prevented from falling off from the cable holding portion while being kept straight, while the protrusion 92 prevents the protruding piece 92 from being bent slightly and passing through the gap, It is possible to enter and exit from the cable holder. Therefore, similarly to the embodiment shown in FIGS. 1 to 3 described above, the position shift and dropout of the brake cable 8 before assembly are suitably suppressed without impairing assembly performance.

  As mentioned above, although one Example of this invention was described in detail with reference to drawings, this invention can also be implemented in another aspect.

  For example, in the embodiment, the case where the present invention is applied to the drum brake 4 that is also used as a service brake has been described. However, the cable guide of the drum brake of the drum-in disk brake provided with the disk brake as the service brake is also described. The present invention applies as well.

  Further, in the embodiment, the open portion 82 is provided between the support portion 70 and the facing portions 74 and 90, but a pair of side wall portions parallel to each other are erected from the two sides of the support portion 70. Thus, the present invention is similarly applied to a cable guide in which an open portion is provided between the tips of the side wall portions. In such an embodiment, for example, a protruding piece extending from one side wall toward the other side wall to an intermediate position thereof may be provided, and the cable 8 may be prevented from falling off by the protruding piece.

  Moreover, in the Example, although the cable holding part was formed in the U-shaped cross section, it can also be formed in appropriate shapes, such as a U-shaped cross section.

  Further, the shape of the fixing portions 58 and 60 and the overall shape of the cable guides 56 and 86 are not limited to the shapes shown in the embodiments, and may be appropriately changed in consideration of the arrangement position, the manufacturing cost, and the like.

  In addition, although not illustrated one by one, the present invention can be appropriately modified without departing from the gist thereof.

It is a top view for demonstrating the structure of the drum brake to which the cable guide of one Example of this invention was applied. It is a top view which expands and shows the cable guide of FIG. 1 in an assembly state. It is sectional drawing of the cable guide of FIG. It is a top view which shows the cable guide of the other Example of this invention in the assembly | attachment state. It is sectional drawing of the cable guide of FIG. It is a top view for demonstrating the conventional cable guide. It is a longitudinal cross-sectional view of the cable guide of FIG. It is a cross-sectional view of the cable guide of FIG.

Explanation of symbols

  2: parking brake device, 4: drum brake, 8: brake cable, 10: backing plate, 12, 14: brake shoe, 56: cable guide, {70: support portion, 72: side wall portion, 74: facing portion} ( Cable holding part), 80: Protrusion (protrusion prevention part)

Claims (4)

In a drum brake in which a brake shoe disposed on a backing plate is mechanically pressed against a rotating drum by applying a tensile force to the brake cable to generate a braking force, the brake shoe is integrally fixed to the backing plate and A cable guide for supporting the brake cable with a predetermined tension and inserting the brake cable into and out of the drum brake,
A cable holding portion that surrounds an outer peripheral surface of the predetermined range in the longitudinal direction of the brake cable so that a part of the circumferential direction of the brake cable is opened by an opening portion having an opening width dimension larger than the diameter;
The brake cable escaped from the open portion accommodated in the cable holding portion by being spaced apart from the cable holding portion by a predetermined distance along the longitudinal direction of the brake cable and positioned on the side of the brake cable. A cable guide for a drum brake, comprising: an escape prevention part that forms a gap through which the brake cable can pass in the radial direction between the cable holding part and the cable holding part. The cable holding part includes a support part provided with a support surface that presses the brake cable in a direction away from the backing plate, an opposing part provided with an opposing surface facing the support surface, and the support part and the opposing part. 2. A cable guide for a drum brake according to claim 1, wherein the cable guide has a U-shaped cross section with a connecting portion for connecting the two at their ends. The escape restraining portion projects from the end portion of the facing portion on the opposite side of the connecting portion along the longitudinal direction of the brake cable and inclines toward the support portion. It is a protrusion that suppresses the escape of the brake cable at the part,
The cable guide for a drum brake according to claim 2, wherein the support portion has a stepped shape in which a position facing the protrusion is lower than a position facing the facing portion. 3. The cable guide for a drum brake according to claim 2, wherein the escape restraining part is a projecting piece projecting from the backing part in a direction away from the backing plate.

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