JP3910460B2 - Drum brake cable guide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a small and light cable guide at a low cost, even when an outer casing is not connected. <P>SOLUTION: In the cable guide 56, an engaging part 72 is engaged with the inside of a mounting hole 70 from the inside of a backing plate 10, and a flange part 74 integrally disposed to project from the engaging part 72 to the outer peripheral side is adhered closely to the inner surface of the backing plate 10, namely the peripheral edge of the mounting hole 70. Therefore, though an outer casing is not disposed and outside directional load (downward of Fig. 3 (b)) is charged in pulling a brake cable 50, the flange part 74 keeps a good mounting state to the backing plate 10, and one relatively small screw 78 simply allows certain and undetachable fixing. Thus, the small and light cable guide 56 can be constituted at the low cost. <P>COPYRIGHT: (C)2003,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drum brake, and more particularly to a cable guide for inserting a brake cable for generating a braking force into and out of the drum brake.
[0002]
[Prior art]
A drum brake that generates a braking force by mechanically pressing a brake shoe disposed on a backing plate against a rotating drum by a brake cable is used for a vehicle parking brake or the like. The structure for introducing the brake cable from the back of the plate into the drum brake is usually configured as shown in FIG. 6 or FIG. In FIG. 6, the mounting hole 102 is formed in the flat portion of the backing plate 100, and the cable guide 104 is fitted from the outside (the lower side of FIG. 6B) and fixed integrally with the bolt 106. A brake cable 110 is inserted into an insertion hole 108 provided in the cable guide 104 so as to be inclined with respect to the plate 100 and introduced into the drum brake. The brake cable 110 is disposed substantially in parallel with the backing plate 100 and is connected to the brake lever. When the tensile force is applied, the brake cable is rotated to generate a braking force. Around the periphery, a return spring (compression coil spring) 112 for returning the brake lever to its original position is disposed concentrically, and one end thereof is seated on the cable guide 104. The brake cable 110 is inserted into the outer casing 114 and guided from a brake operation member such as an operation lever on the tensile force application side to the drum brake. The end of the outer casing 114 is connected to the cable guide 104. In addition to being fixed, it is positioned on the vehicle body or the like by a clamp 116 in the vicinity thereof. 6A is a front view seen from the inside of the drum brake in a direction perpendicular to the backing plate 100 and provided with brake shoes and the like, and FIG. 6B is a sectional view taken along line BB in FIG. It is.
[0003]
In this case, since the direction of the brake cable 110 changes toward the outside at the insertion hole 108 portion, when the brake operation member is operated and the brake cable 110 is pulled in the lower right direction in FIG. The cable guide 104 is subjected to a load in the outward direction from the backing plate 100 (downward direction in FIG. 6B), but the cable guide 104 is relatively pressed by the outer casing 114 against the backing plate 100 to cancel out. Therefore, the fixed state with respect to the backing plate 100 can be satisfactorily maintained with only one bolt 106.
[0004]
Further, FIG. 7 shows that the inclined portion 120 that is substantially perpendicular to the posture of the brake cable 110, that is, the pulling direction is provided in the backing plate 100 by drawing or the like, and the cable guide 122 is fixed substantially perpendicular to the inclined portion 120. Thus, the cable guide 122 is provided with a plurality of locking claws 124 and is inserted from the outside into the mounting hole 126 provided in the inclined portion 120 so that it cannot be detached with one touch via the locking claw 124. Can be attached to the backing plate 100.
[0005]
[Problems to be solved by the invention]
In recent years, it has been considered that the brake cable is divided into a first cable on the drum brake side and a second cable on the tensile force application side, and in this case, the first cable on the drum brake side is connected to the outer cable. It extends outward from the backing plate without a casing. Therefore, the action of pressing the cable guide 104 against the backing plate 100 by the outer casing 114 as shown in FIG. 6 cannot be obtained, and it is necessary to increase the mounting strength of the cable guide 104. There is a problem that the cable guide 104 is large and heavy, and the cost is high.
[0006]
As shown in FIG. 7, when the tension direction of the brake cable 110 and the attitude of the cable guide 122 substantially match, the cable guide 122 is not heavily loaded when the brake cable 110 is pulled, and the outer casing 114 is not connected. Although it is suitably applied to the case, since it is necessary to perform a severe drawing process on the backing plate 100, it is necessary to increase the manufacturing process of the backing plate 100, and there are cases where the material is restricted and the cost is increased. .
[0007]
The present invention has been made in the background of the above circumstances, and the object thereof is that a severe drawing process for the backing plate is unnecessary, and even when the outer casing is not connected, the cable guide is small and lightweight, It is to be able to configure at low cost.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, a first invention is a drum brake in which a brake shoe disposed on a backing plate is mechanically pressed against a rotating drum when a tensile force is applied to a brake cable to generate a braking force. The brake cable is configured separately from the anchor and is integrally fixed to the backing plate, and the brake cable disposed substantially parallel to the backing plate inside the drum brake is inclined with respect to the backing plate. A cable guide that is inserted into and out of the drum brake, and (a) is fitted into the mounting hole provided in the backing plate from the inside of the backing plate and is inclined with respect to the backing plate. An insertion hole through which the brake cable is inserted. A fitting portion having, and (b) a flange portion that is integrally provided so as to protrude from the fitting portion to the outer peripheral side, and is a peripheral portion of the mounting hole and is brought into contact with the inner surface of the backing plate; It is characterized by having.
The second invention includes: (a) a pair of arc-shaped brake shoes disposed substantially symmetrically on the backing plate so as to be close to and away from each other; and (b) one of the pair of brake shoes with respect to the backing plate. A brake lever coupled to be rotatable about a substantially vertical axis, and (c) a strut disposed across the brake lever and the other brake shoe, and (d) When the brake cable connected to the brake lever is pulled in a direction substantially parallel to the backing plate and the brake lever is rotated, the pair of brake shoes are separated from each other via the strut, manner in pressed against the rotary drum drum brake that generates a braking force, integrally with said backing plate is configured separately from the (e) anchor Is fixed, in the interior of the drum brake to the brake cable which is disposed substantially parallel to the backing plate, a cable guide for inserting in and out of the drum brake is tilted relative to the backing plate, ( f) A fitting that is inserted into the mounting hole provided in the backing plate from the inside of the backing plate and has an insertion hole through which the brake cable is inserted so as to be inclined with respect to the backing plate. And (g) a flange portion that is integrally provided so as to protrude from the fitting portion to the outer peripheral side, and is a peripheral portion of the mounting hole and is brought into contact with the inner surface of the backing plate. It is characterized by.
[0009]
The third invention is the cable guide for the drum brake of the first invention or the second invention . (A) The brake cable is divided into a first cable on the drum brake side and a second cable on the tension applying side. (B) The first cable extends outside the backing plate without an outer casing.
[0011]
【The invention's effect】
In such a cable guide, the fitting portion having the insertion hole is fitted into the mounting hole from the inside of the backing plate, and the flange portion integrally provided so as to protrude from the fitting portion to the outer peripheral side is Since the outer periphery of the mounting hole is in contact with the inner surface of the backing plate, even when there is no outer casing and a load in the outward direction is applied when the brake cable is pulled, the flange is attached to the backing plate. Can be maintained well, and the cable guide can be made small, light and inexpensive. In addition, it is not always necessary to perform a severe drawing process on the backing plate, the backing plate drawing process can be simplified, the degree of freedom in setting the material is increased, and the cost can also be reduced in this respect.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The present invention includes, for example, (a) a pair of arc-shaped brake shoes disposed substantially symmetrically on a backing plate so as to be close to and away from each other, and (b) one of the pair of brake shoes with respect to the backing plate. A brake lever connected to be rotatable about a substantially vertical axis, and (c) a strut disposed across the brake lever and the other brake shoe, and (d) When the brake cable connected to the brake lever is pulled in a direction substantially parallel to the backing plate and the brake lever is rotated, the pair of brake shoes are separated from each other via the struts and disposed on the wheel. It is preferably applied to a vehicle brake device for a parking brake or a service brake that generates a braking force when pressed by a rotating drum. The present invention can also be applied to other vehicle brake devices such as a formula and drum brakes of brake devices other than vehicles. The engagement structure between the brake lever and the brake shoe and the engagement structure between the brake lever and the strut may be connected by, for example, a connection pin that is substantially perpendicular to the backing plate. It is also possible to simply contact with a relative rotation.
[0013]
For example, the cable guide can be fixed to the backing plate only by tightening the fitting portion with respect to the mounting hole. However, with the flange portion in contact with the inner surface of the backing plate, the flange portion can be secured using screws and nuts. Is fixed to the backing plate, the tip of the protrusion that is provided integrally with the flange and protrudes from the through hole of the backing plate is crimped, a toothed disc spring washer is attached to the protrusion, It can also be fixed to the backing plate so that it cannot be removed by using a separate fixing means such as attaching a predetermined retaining member to the protruding fitting portion. One fixing means may be provided, but a plurality of fixing means may be provided if necessary. The shape of the mounting hole provided in the backing plate is desirably substantially the same as the shape of the fitting portion, but there may be a gap.
[0014]
Flange portion is preferably provided on the entire circumference of the fitting portion may be provided to separate radially like circumferential direction.
[0015]
In the cable guide according to the present invention, the brake cable is divided into a first cable on the drum brake side and a second cable on the tensile force application side, and the first cable extends outside the backing plate without an outer casing. It is preferably applied when an outward load acts when the brake cable is pulled, but when the brake cable is composed of a single cable, the outer casing is connected to the cable guide, or The cable guide of the present invention can also be used when a load in the outward direction hardly acts when the brake cable is pulled. Each of the first cable and the second cable of the second invention may be further configured by a plurality of cables.
[0016]
The backing plate is mainly composed of a flat surface portion substantially parallel to a reference plane of the drum brake where the pair of brake shoes approach and separate, that is, a plane perpendicular to the rotation center line of the rotating drum, and the cable guide of the present invention. For example, although it is disposed on the flat surface portion, it may be disposed on a portion inclined with respect to the reference plane by drawing or the like.
[0017]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
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 a brake operating unit, and the operation lever 6 is a parking brake operation member that applies a tensile force.
[0018]
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, i.e., 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 over 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.
[0019]
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 front end (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 an 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.
[0020]
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.
[0021]
FIG. 2 shows an example of the cable connector 54. The cross section is substantially C-shaped, and the pair of side wall portions 58 and 60 are provided with notch-hole-shaped locking portions 62 and 64, respectively. The cylindrical cable ends 50e and 52e integrally fixed to the connection side end portions of the cable 50 and the second cable 52 are locked by the locking portions 62 and 64, respectively. Regardless of this, the first cable 50 and the second cable 52 are integrally connected so as to prevent them from separating. The cable connector 54 is made of an elastically deformable metal plate material such as spring steel, and the opening side (upper side in the drawing) of the side wall portions 58 and 60 is connected as shown in FIG. The cable ends 50e and 52e may be fitted into the locking portions 62 and 64 while being pushed and expanded by the cable ends 50e and 52e.
[0022]
3A and 3B are diagrams for explaining the cable guide 56. FIG. 3A is a front view corresponding to FIG. 1A, FIGS. 3B and 3C are cross-sectional views taken along line BB in FIG. It is C sectional drawing. The cable guide 56 is disposed on a flat surface portion that constitutes the main body of the backing plate 10, and includes a fitting portion 72 that is fitted into a mounting hole 70 provided in the backing plate 10, and an outer periphery from the fitting portion 72. And a flange portion 74 provided integrally so as to protrude to the side. The fitting portion 72 is fitted into the mounting hole 70 from the inside of the backing plate 10, that is, from the upper side in FIG. 3B, and the flange portion 74 is a peripheral portion of the mounting hole 70. The cable guide 56 is adapted to be seated in close contact with the side surface, and one screw 78 as a fixing means passes through the flange portion 74 and the backing plate 10 and is screwed into the nut 80. It is integrally fixed to the backing plate 10. The flange portion 74 is provided continuously over the entire circumference of one end portion of the fitting portion 72, that is, the end portion located inside the backing plate 10. The nut 80 is integrally fixed to the back side (outer side) of the backing plate 10 in advance by projection welding or the like.
[0023]
The fitting portion 72 is provided with an insertion hole 82 through which the first cable 50 is inserted so as to be inclined with respect to the backing plate 10, and is arranged substantially parallel to the backing plate 10 inside the drum brake 4. The first cable 50 to be provided extends obliquely to the outside of the backing plate 10 through the insertion hole 82 while changing the direction outward at the cable guide 56 portion. Therefore, when the operation lever 6 is operated and the first cable 50 is pulled in the lower right direction in FIG. 3B, the cable guide 56 has a direction toward the outside from the backing plate 10 (in FIG. 3B). A downward load is applied. In addition, a flat spring receiving seat surface 84 is provided at one opening of the insertion hole 82, that is, an opening located inside the backing plate 10, and is arranged to wind the first cable 50. One end of the return spring (compression coil spring) 38 can be seated.
[0024]
As described above, in the parking brake device 2 of the present embodiment, the brake cable 8 is configured by the first cable 50 connected to the drum brake 4 and the second cable 52 connected to the operation lever 6. After assembling the drum brake 4 in which the first cable 50 is connected to the brake lever 34 to the vehicle, the first cable 50 extending from the drum brake 4 may be connected to the second cable 52 via the cable connector 54. The arrangement work of the cable 8 becomes easy. That is, it is easier to install the brake cable than when the brake cable is connected to the brake lever 34 of the drum brake 4 after the drum brake 4 is attached to the vehicle using a single brake cable. It is.
[0025]
On the other hand, in such a cable split type parking brake device 2, since the outer casing is not connected to the cable guide 56, the cable guide 56 is pulled outward (downward in FIG. 3B) when the brake cable 8 is pulled. Although the load in the direction is applied, the cable guide 56 of this embodiment is configured so that the fitting portion 72 is fitted into the mounting hole 70 from the inside of the backing plate 10 and protrudes from the fitting portion 72 to the outer peripheral side. Since the flange portion 74 provided integrally with the inner surface of the mounting plate 70 is in close contact with the inner surface of the backing plate 10, the flange portion 74 is attached to the backing plate 10 regardless of the load in the outer direction. The mounting condition is maintained well, and it is possible to securely fix it with a relatively small screw 78 so that it cannot fall off. The cable guide 56 can be made small, light and inexpensive.
[0026]
Further, unlike the cable guide 122 of FIG. 7, it is not necessary to perform a severe drawing process on the backing plate 10, so that the drawing process of the backing plate 10 can be simplified and the degree of freedom in setting the material is increased. In this respect, the cost can be reduced.
[0027]
In the above embodiment, the cable guide 56 is fixed to the backing plate 10 by the screw 78 and the nut 80. However, for example, as shown in FIG. A toothed disc spring washer 90 is pushed into and fitted into the tip of a cylindrical projection 88 projecting from the through hole 86 to the opposite side (outside), or the tip of the projection 88 is crimped as shown in FIG. Various fixing means such as crushing can be employed. 4 (a) and 5 are cross-sectional views corresponding to FIG. 3 (c), and FIG. 4 (b) is a bottom view seen from below in FIG. 4 (a).
[0028]
As mentioned above, although the Example of this invention was described in detail based on drawing, these are one embodiment to the last, and this invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a parking brake device to which the present invention is applied.
2A and 2B are diagrams showing a cable connector of the parking brake device of FIG. 1, wherein FIG. 2A is a perspective view of the connected state, and FIG. 2B is a diagram when connecting the first cable and the second cable to the cable connector. It is a perspective view explaining the procedure of.
3 is a view showing a cable guide of the parking brake device of FIG. 1, in which (a) is a front view corresponding to FIG. 1, (b) is a sectional view taken along line BB in (a), and (c) is (a). It is CC sectional drawing in).
FIGS. 4A and 4B are views showing another embodiment in which the cable guide of FIG. 3 is fixed to the backing plate. FIG. 4A is a sectional view corresponding to FIG. 3C, and FIG. FIG.
5 is a view showing still another aspect of fixing the cable guide of FIG. 3 to the backing plate, and is a cross-sectional view corresponding to FIG. 3 (c).
6A and 6B are diagrams for explaining a conventional cable guide, in which FIG. 6A is a front view, and FIG. 6B is a cross-sectional view taken along line BB in FIG.
FIG. 7 is a view showing another example of a conventional cable guide.
[Explanation of symbols]
2: parking brake device 4: drum brake 8: brake cable 10: backing plate 12, 14: brake shoe 27: rotating drum 30: strut 32: anchor 34: brake lever 50: first cable 52: second cable 56: cable Guide 70: Mounting hole 72: Fitting part 74: Flange part 82: Insertion hole

Claims (3)

In the drum brake in which a brake shoe disposed on the backing plate is mechanically pressed against the rotating drum by applying a tensile force to the brake cable to generate a braking force, the backing plate is configured separately from the anchor. A cable guide that is fixed integrally with the drum brake and is disposed substantially in parallel with the backing plate inside the drum brake so that the brake cable is inclined with respect to the backing plate and inserted into and out of the drum brake. There,
A fitting portion that is fitted into the mounting hole provided in the backing plate from the inside of the backing plate and has an insertion hole that is provided so as to be inclined with respect to the backing plate and into which the brake cable is inserted. ,
A flange portion that is integrally provided so as to protrude from the fitting portion to the outer peripheral side, and is a peripheral portion of the mounting hole and is brought into contact with the inner surface of the backing plate;
A cable guide for a drum brake, characterized by comprising: A pair of arc-shaped brake shoes disposed substantially symmetrically on the backing plate so as to be close to and away from each other;
A brake lever connected to one of the pair of brake shoes so as to be relatively rotatable about an axis substantially perpendicular to the backing plate;
A strut disposed across the brake lever and the other brake shoe;
And the brake cable connected to the brake lever is pulled in a direction substantially parallel to the backing plate and the brake lever is rotated, so that the pair of brake shoes are separated from each other via the strut. In a drum brake that is mechanically pressed against a rotating drum to generate a braking force,
The brake cable is configured separately from the anchor and is integrally fixed to the backing plate, and the brake cable disposed substantially parallel to the backing plate inside the drum brake is inclined with respect to the backing plate. A cable guide that is inserted into and out of the drum brake,
A fitting portion that is inserted into the mounting hole provided in the backing plate from the inside of the backing plate and has an insertion hole that is provided so as to be inclined with respect to the backing plate and into which the brake cable is inserted. ,
A flange portion that is integrally provided so as to protrude from the fitting portion to the outer peripheral side, and is a peripheral portion of the mounting hole and is brought into contact with an inner surface of the backing plate;
A cable guide for a drum brake, characterized by comprising: The brake cable is divided into a first cable on the drum brake side and a second cable on the tensile force application side,
The cable guide for a drum brake according to claim 1 or 2 , wherein the first cable extends to the outside of the backing plate without an outer casing.

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