JP2520404Y2 - Drum brake with parking brake mechanism - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum brake with a parking brake mechanism, and more particularly to a technique for preventing the parking cable from coming off from a U-shaped portion of the parking brake lever.

2. Description of the Related Art A brake shoe, a parking brake lever that is long and has a U-shaped portion at one end, and is rotatably attached to the brake shoe at the other end, and a metal fitting is fixed at the one end. The one end of the parking brake lever is inserted into the U-shaped portion through the opening on the side opposite to the bottom side of the U-shaped portion of the parking brake lever, so that the metal fitting prevents relative movement in one direction. Conventionally, a drum brake with a parking brake mechanism of a type including a parking cable connected to a U-shaped portion has been provided.

In such a type of drum brake with a parking brake mechanism, the parking brake is operated by pulling the parking cable in the one direction, and the stroke of the parking cable should be adjusted after the assembly to the vehicle. And the one end portion side of the parking cable is U-shaped of the parking brake lever based on the engagement between the metal fitting and a predetermined stopper portion provided on the parking brake lever.
It is done to prevent it from coming off the opening of the letter-shaped part.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the stage before the stroke adjustment of the parking cable, the parking cable is relatively relatively moved in the direction opposite to the one direction (return direction) with respect to the U-shaped portion of the parking brake lever. Since the vehicle is in a state of being relatively movable relatively, for example, when the parking cable is relatively relatively moved in the returning direction with respect to the U-shaped portion due to vibration or impact when the drum brake is assembled to the vehicle, There is a possibility that the fitting between the metal fitting and the stopper portion cannot be obtained properly, and the one end portion side of the parking cable may come out of the opening of the U-shaped portion of the parking brake lever.

On the other hand, when the parking cable is moved relative to the U-shaped portion in the return direction, the parking cable is prevented from coming off the opening of the U-shaped portion based on the engagement between the metal fitting and the stopper portion. It is conceivable to determine the shape, formation position, etc. of the stopper portion so as to surely prevent it. However, in this case, the presence of the stopper portion provided on the parking brake lever causes U of the parking cable. It is unavoidable that the workability at the time of connecting to the character portion is impaired.

The present invention has been made in view of the above circumstances, and its purpose is to connect a parking cable to a U cable.
Due to the fact that the parking cable connected to the U-shaped portion of the parking brake lever is moved relatively to the U-shaped portion in the returning direction without substantially impairing the workability when connecting to the U-shaped portion. (EN) It is an object to provide a drum brake with a parking brake mechanism that can more reliably prevent it from coming off the opening of the U-shaped portion.

Means for Solving the Problems The gist of the present invention for achieving the above-mentioned object is to provide a drum brake with a parking brake mechanism of the type described above, wherein the parking cable is provided in a direction opposite to the one direction. A disengagement prevention that prevents one end portion side of the parking cable from being disengaged from the opening of the U-shaped portion due to being moved relative to the U-shaped portion of the parking brake lever, based on the engagement with the metal fitting. Means are provided in the brake shoe.

In this way, the parking cable is moved relative to the U-shaped portion of the parking brake lever in its return direction, so that one end of the parking cable is opened at the U-shaped portion. It can be prevented from being disengaged based on the engagement between the metal fitting fixed to one end of the parking cable and the disengagement prevention means provided on the brake shoe. Since the disconnection prevention means is provided on the brake shoe, if the parking cable is connected to the U-shaped portion while the parking brake lever is slightly rotated, the disconnection prevention means prevents the parking cable from being released. It is possible to suitably prevent the workability at the time of connection to the U-shaped portion from being impaired. As a result, the degree of freedom in designing the disengagement prevention means can be suitably obtained compared to the case where the disengagement prevention means is provided on the parking brake lever. Therefore, the disengagement prevention means provided on the brake shoe can more securely remove the parking cable. Can be prevented.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a view showing an example of a drum brake with a parking brake mechanism to which the present invention is applied, showing a main part. In the figure, on the backing plate 10, a pair of arcuate brake shoes 12 and 14 are supported by shoe hold down devices 16 and 18 so as to be capable of expanding. The brake shoes 12 and 14 are a shoe web 20 positioned substantially parallel to the plate surface of the backing plate 10, and a shoe rim fixed to the outer peripheral side end surface of the shoe web 20.
22 and a lining 24 fixed to the outer peripheral surface of the shoe rim 22.

The opposite ends of the brake shoes 12 and 14 are respectively brought into contact with the side surfaces of the anchor 26 fixed on the backing plate 10, and the brake shoes 12 and 14 are provided.
The other end of the wheel cylinder 28 is engaged with both ends of a wheel cylinder 28 fixed on the backing plate 10. On the surface of the brake shoe 12 on the backing plate 10 side of the shoe web 20, a parking brake lever 30 having a long plate shape is rotatably attached at one end by a pin 32, and the shoe web 20 of the brake shoe 12 is provided.
And parking brake lever 30 and brake shoe 14
Struts 34 are provided between the shoe web 20 and the shoe web 20. Incidentally, 36 is a shoe return spring.

The other end of the parking brake lever 30 has a first
As shown in FIGS. 2 and 2, a hook-shaped U-shaped portion 38 is formed by bending the other end, and one end of the parking cable 40 is connected to the U-shaped portion 38. Has been done. That is, a metal fitting 42 is fixed to one end of the parking cable 40 by caulking or the like, and a portion of the parking cable 40 located near the metal fitting 42 is U in a direction substantially perpendicular to the axis of the parking cable 40. By being inserted into the U-shaped portion 38 from the opening 44 (see FIG. 2) on the side opposite to the bottom side of the U-shaped portion 38, the end surface of the metal fitting 42 on the brake shoe 14 side and the U-shaped portion 38 are formed. It is connected to the U-shaped portion 38 so as not to be relatively movable in one direction (to the right in FIGS. 1 and 2) based on the contact of.

On the other end side of the parking brake lever 30, a portion protruding toward the shoe rim 22 side of the brake shoe 12 from a position close to the base of the U-shaped portion 38 and located on the tip side is slightly closer to the shoe web 20 side. Bent over to 46
Is integrally provided, and the return position of the parking brake lever 30 is regulated based on the contact between the tip of the protrusion 46 and the shoe rim 22, and the protrusion 46 and the metal fitting 42 are also provided. The opening of the U-shaped portion 38 of the parking cable 40 based on the engagement with the vertical direction in FIG.
It is designed to prevent it from coming off from 44. 48
Is a return spring.

In the drum brake configured as described above,
By pulling the parking cable 40 in one direction (rightward in FIG. 1), the parking brake lever 30 is rotated counterclockwise to operate the parking brake. Since the braking operation is well known and is not always necessary for understanding the present invention, its detailed description is omitted.

Here, in the present embodiment, as shown in FIGS. 1 and 2, the shoe rim 22 of the brake shoe 12 is further added.
Is partially cut and raised toward the inner peripheral side, so that it is positioned substantially at a right angle to the axis of the parking cable 40 and faces the surface of the metal fitting 42 opposite to the U-shaped portion 38 side with a slight gap. U-shaped portion 38 in a direction (return direction) opposite to the one direction of the parking cable 40 is provided with a protrusion 50 for
Since the relative movement of the U-shaped portion 38 of the parking cable 40 is restricted by the contact between the metal fitting 42 and the protrusion 50, the U-shaped portion 38 of the parking cable 40 is more reliably prevented from coming off the opening 44. Therefore, in the present embodiment, the protrusion 50 constitutes a detachment preventing means.

By the way, in the above-configured drum brake with a parking brake mechanism, after assembling it in a vehicle, adjust the stroke of the parking cable 40 at the end of the parking cable 40 opposite to the parking brake lever 30 side. Is being done. In the stage before the stroke adjustment of the parking cable 40, the parking cable 40 is normally in a state where it can relatively move relatively to the U-shaped portion 38 of the parking brake lever 30 in the return direction. For this reason,
In the conventional case shown in FIG. 6 and FIG. 7 (which is different from the embodiment of the present invention only in that the protrusion 50 is not provided), for example, due to vibration or shock when assembling the drum brake to the vehicle, Parking cable 40 is U-shaped
When the parking cable 40 is relatively moved relatively to the return direction with respect to 38, one end side of the parking cable 40 bends and becomes cheaper, and the engagement between the metal fitting 42 and the protruding portion 46 in the vertical direction in FIG. 6 is suitably obtained. With the relative movement of the parking cable 40, the metal fitting 42 is moved upward in FIG. 6 along the inner peripheral surface of the shoe rim 22, while one end of the parking cable 40 is moved to the parking brake lever.
There is a possibility that the U-shaped portion 38 of 30 may come off the opening 44.

On the other hand, according to the present embodiment, the contact between the metal fitting 42 and the protrusion 50 projecting from the shoe rim 22 of the brake shoe 12 causes the parking cable 40 to move relative to the U-shaped portion 38 in the returning direction. Since the movement is restricted, the metal fitting 42 and the protrusion 46 of the parking brake lever 30 can be preferably held in a state in which they can be engaged in the vertical direction in FIG. As a result, the parking cable 40 can be more reliably prevented from coming off as compared with the conventional case in which the parking cable 40 is prevented from coming off only by the protrusion 46.

By the way, it is conceivable to provide the parking brake lever 30 with a detachment preventing means such as the protrusion 50, but in this case, the parking cable 40 by the detachment preventing means is provided.
In order to sufficiently secure the detachment prevention effect, it is unavoidable that workability when connecting the parking cable 40 to the U-shaped portion 38 of the parking brake lever 30 is deteriorated due to the presence of the detachment prevention means. However, according to the present embodiment, the protrusion 50 as the detachment preventing means is
Since it is provided in 12, parking brake lever 30
U in the state of being slightly rotated clockwise in FIG.
If the parking cable 40 is connected to the character-shaped portion 38, the presence of the projection 50 will hardly impair the workability when connecting the parking cable 40.

Further, according to the present embodiment, since the projection 50 is formed by cutting and raising a part of the shoe rim 22, there is an advantage that the above effect can be obtained without increasing the number of parts or the weight.

In the above-described embodiment, the shoe rim 22 of the brake shoe 12 is provided with the protrusion 50 that is positioned substantially at right angles to the axis of the parking cable 40 and that faces the metal fitting 42 in the axis direction of the parking cable 40. However, this is not always necessary. For example, as shown in FIG. 3, the metal fitting 42 is covered from the opening 44 side of the U-shaped portion 38 while tilting at a predetermined angle with respect to the axis of the parking cable 40, and the metal fitting 42 and the parking are parked. The shoe rim 22 may be provided with projections 52 that face each other in the axial direction of the cable 40, or as shown in FIGS. 4 and 5, a projection 54 that faces the shoe web 20 side surface of the metal fitting 42 may be provided. It may be provided at 22. Third above
In the protrusion 52 shown in the figure, the U of the parking cable 40 is
At the time of relative movement in the return direction with respect to the letter-shaped portion 38, not only is the relative movement regulated to some extent based on the contact between the protrusion 52 and the metal fitting 42, but also the metal fitting 42 has a U-shaped portion along the inclined surface of the protrusion 52. Guided to the bottom of 38, parking cable
The U-shaped portion 38 of 40 is more reliably prevented from coming off the opening 44. In this case, the protrusion 52 is the parking cable.
Stick out the metal fitting 42 in a U-shaped part 38 by protruding in a state parallel to the axis of 40.
It may be provided so as to cover from the opening 44 side. Further, in the projection 54 shown in FIG. 4 and FIG.
By restricting the movement of the shoe web to the side,
The metal fitting 42 and the parking brake lever for preventing the U-shaped portion 38 of the parking cable 40 from coming off from the opening 44.
The engagement with the protrusion 46 of 30 in the vertical direction in FIG. 4 can be obtained more reliably.

Further, the projections 50, 52, 54 in the above-mentioned three embodiments may be combined appropriately, or the U-shaped portion of the metal fitting 42 may be used.
A single disengagement prevention engageable with a plurality of surfaces of the surface opposite to the 38 side, the surface located on the opening 44 side of the U-shaped portion 38 of the metal fitting 42, and the surface of the metal fitting 42 on the shoe web 20 side. Means can also be provided.

Further, in the above-mentioned three embodiments, the protrusions 50, 52, 54 as the detachment preventing means are the shoe rims of the brake shoe 12.
It is formed by cutting and raising a part of 22. However, the disengagement preventing means as described above may be provided on the shoe web 20, or the disengagement preventing means composed of a separate member may be fixed to the brake shoe 12. There is no problem in doing so.

Further, in the above-described embodiment, the U-shaped portion 38 is integrally formed with the parking brake lever 30 by bending the end portion of the parking brake lever 30 into a hook shape. It may be formed by fixing a predetermined member to.

In the above-described embodiment, the U-shaped portion 38 has a pair of inner wall surfaces that are parallel to each other and has a literal U-shape, but this is not always necessary. May be That is, the U-shape in the U-shaped portion of the claim is used to include a V-shape having a shape similar to the U-shape.

Further, in the above-described embodiment, the case where the present invention is applied to the leading trailing type drum brake has been described. However, even if other drum brakes such as a duo servo type drum brake are used, the U of the parking brake lever is used. The present invention can be applied to any device provided with a parking brake mechanism in which a parking cable is connected to a character portion such that the parking cable cannot move relatively in one direction. In this case, it goes without saying that the shoe gap automatic adjustment mechanism may be provided.

In addition, the present invention can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a view showing a main part of an example of a drum brake with a parking brake mechanism to which the present invention is applied, and is a view in which a part is cut away. Figure 2 shows II in Figure 1.
It is a figure which expands and shows the principal part of a II cross section. FIG. 3 is a view showing another example of the present invention and is a view corresponding to an enlarged view of a main part of FIG. FIG. 4 is a view showing still another example of the present invention and corresponds to FIG. Figure 5 is the fourth
It is a figure which expands and shows the principal part of the VV cross section in a figure. FIG. 6 is a view showing a main part of an example of a conventional drum brake with a parking brake mechanism, and is a view showing one state when a parking cable and a U-shaped part are relatively moved. FIG. 7 is an enlarged view showing a main part of a cross section taken along line VII-VII in FIG. 12: Brake shoe 30: Parking brake lever 38: U-shaped part 40: Parking cable 42: Metal fittings 50, 52, 54: Protrusion (remove prevention means)

Claims (1)

(57) [Scope of utility model registration request] 1. A brake shoe, a parking brake lever which is longitudinal and has a U-shaped portion at one end, and is rotatably attached to the brake shoe at the other end, and a metal fitting at the one end. Is fixed, and the one end side is inserted into the U-shaped portion through the opening on the side opposite to the bottom side of the U-shaped portion of the parking brake lever, so that the metal fitting prevents relative movement in one direction. In a drum brake with a parking brake mechanism of a type including a parking cable connected to the U-shaped portion in a closed state, the parking cable is moved relative to the U-shaped portion in a direction opposite to the one direction. Due to the engagement with the metal fitting, the disconnection preventing means for preventing the one end side of the parking cable from coming out of the opening of the U-shaped portion due to the above is provided as the blur prevention means. A drum brake with a parking brake mechanism, which is provided on the shoe.