JP4020487B2 - Brake shoe for drum brake - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a brake shoe for a drum brake, and more particularly to a positioning structure for a shoe rim and a shoe web at the time of projection welding.
[0002]
[Prior art]
A brake shoe for this kind of drum brake is usually configured as shown in FIGS. FIG. 8 is a state diagram before the projection welding of the shoe rim 3 and the shoe web 4 constituting the brake shoe 2, and the substantially strip-like shoe rim 3 is bent at three right angles on both sides in the width direction. A bead portion 3a is formed, and this bead portion 3a is movably mounted on a stationary member of a known drum brake device (not shown). In addition, a plurality of welding projections 3b (seven locations in the figure) project from the center line in the width direction, and positioning holes 3c are formed at appropriate positions in the circumferential direction. Normally, the positioning hole 3c is a rectangular hole as shown in the enlarged view of FIG. 9 or a round hole as shown in FIG. 10, and has a shape that can limit the displacement of the shoe rim 3 in the circumferential direction with respect to the shoe web 4. .
[0003]
The substantially crescent-shaped shoe web 4 is appropriately formed with an insertion hole 4a through which a shoe hold pin (not shown) is loosely fitted and a notch 4f for hooking a shoe return spring (not shown), and the shoe rim 3 is formed on the outer periphery thereof. A positioning projection 4c is formed in the positioning hole 3c with a slight gap in the circumferential direction.
Usually, both the shoe rim 3 and the shoe web 4 are processed from the coil material by press progressive molding, and the shoe rim 3 is press-bended so that the welding projection 3b is substantially along the outer peripheral surface of the shoe web 4. R-bending is formed by roller bending.
[0004]
As shown in FIG. 8, the projection welding of the shoe rim 3 and the shoe web 4 is performed on the outer circumferential surface of the shoe web 4 supported by the lower electrode (not shown) on the projection 4c for positioning the shoe web 4. fitting the 3 holes 3c for positioning engagement with aligned mounts the welding protrusion 3b of the shoe rim 3 while. Thereafter, the upper electrode 6 indicated by a two-dot chain line is lowered and the two are integrated under a predetermined welding condition. The integrated shoe rim 3 and shoe web 4 are appropriately rust-proofed, and a brake lining 5 that frictionally engages with a brake drum (not shown) is bonded to the outer peripheral surface of the shoe rim as shown in FIG. Thus, the brake shoe 2 is completed by being fixed.
[0005]
[Problems to be solved by the invention]
The above-described brake shoes for drum brakes have the following problems.
[0006]
<A> If the projection 4c for positioning the shoe web 4 protrudes from the joint surface of the brake lining 5 of the shoe rim 3 after the projection is welded, it breaks when the brake lining 5 is fixed, or a gap is formed between the shoe rim 3 and the shoe rim 3. A design that does not allow the positioning projection 4c to protrude from the joint surface of the brake lining 5 of the shoe rim 3 is a precondition because it causes insufficient strength or causes problems such as inducing vibration during braking due to the gap. Become.
However, since the positioning hole 3c is simply drilled in the flat shoe rim 3 as in the prior art, the amount of engagement with the positioning projection 4c of the shoe web 4 is reduced by the height of the welding projection 3b. The positioning of the positioning hole 3c with respect to the positioning protrusion 4c is troublesome and causes a reduction in work efficiency.
<B> In particular, if there is any misalignment between the lower electrode and the upper electrode 6, when the upper electrode 6 is lowered, it comes into contact with the shoe rim 3 (one of the end portions in the circumferential direction comes first). per, the other from end to situations that) flying, extra circumferential direction of the easy the management Hanrawashii cause displacement of the shoe rim 3.
<C> also possible to completely eliminate the deviation of the shoe rim 3 from above are extremely difficult, or requires a selection steps were equal uneconomical scrap is generated.
[0007]
The present invention has been made to solve the above-described problems, and an object of the present invention is to make it easy to position a shoe rim at the time of brake shoe projection welding and to prevent the occurrence of circumferential displacement. It is to provide an excellent brake shoe.
[0008]
[Means for Solving the Problems]
The invention according to claim 1, a shoe rim of the brake lining is fixed to the outer peripheral surface, the brake shoes of the drum brake comprising a shoe webs are integrated by a plurality of projections welded to the inner circumferential surface of the shoe rim, A positioning hole drilled in the shoe rim, and a protrusion for increasing the allowance, which is arranged facing the circumferential direction by causing the peripheral edge of the positioning hole to protrude toward the outer peripheral surface of the shoe web. A brake shoe for a drum brake, characterized in that a positioning projection formed on the shoe web and entering the positioning hole between the projections for increasing the hook allowance is provided .
[0009]
According to a second aspect of the present invention, in the first aspect, the protruding portions are formed on both sides in the direction orthogonal to the circumferential direction of the protrusion for increasing the hooking allowance to limit the displacement in the width direction of the shoe rim with respect to the shoe web. A brake shoe for a drum brake, characterized in that it is configured as described above .
[0010]
According to a third aspect of the present invention, in the first aspect, a recess is formed on both sides in the circumferential direction of the positioning projection formed on the shoe web, and the projection for increasing the allowance is immersed in the recess. This is a brake shoe for drum brakes.
[0011]
According to a fourth aspect of the present invention, in any one of the first to third aspects, at the time of the projection welding of the shoe rim and the shoe web, the projection for increasing the allowance protruding from the shoe rim is welded simultaneously. and wherein, is a brake shoe for a drum brake.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
In addition, the same components and parts as those of the above-described prerequisite technology (FIGS. 8 to 11) of the present invention are denoted by the same reference numerals, and detailed description thereof is omitted.
[0013]
1 to 3 show a first embodiment of the present invention, FIG. 1 is a front view showing a state before projection welding of a shoe rim 3 and a shoe web 4, and FIG. 2 is an enlarged view showing a circumferential positioning portion of FIG. FIG. 3 is a plan view of FIG.
[0014]
A shoe rim 3 having bead portions 3a on both sides in the width direction and a plurality of welding projections 3b formed on the center line in the width direction is opposed to a predetermined position on the center line in the width direction with a gap in the circumferential direction. A protrusion 3d for increasing the allowance is integrally protruded in the same direction and at the same height as the welding protrusion 3b by cutting with a press. As a result, a positioning hole 3c in the circumferential direction is formed between the opposing protrusions 3d for increasing the allowance . Further, it is not essential to match the height of the protrusion 3d for increasing the allowance to the height of the welding protrusion 3b, and there may be a slight difference in height. In short, the optimum height may be determined in consideration of the plate thickness of the shoe rim 3 and the height of the welding projection 3b.
In FIG. 3, projecting portions are provided on both sides in the width direction of the positioning hole 3 c formed by the opposing protrusion 3 d for increasing the allowance so as to approach the left and right protrusions 3 d for increasing the allowance. 3e is formed.
[0015]
A shoe web 4 has the same shape as the above-described conventional shoe web 4, and the height of the positioning projection 4 c is set slightly lower than the plate thickness of the shoe rim 3.
[0016]
According to the configuration described above, when the welding projection 3b of the shoe rim 3 is placed on the outer peripheral surface of the shoe web 4, as is clear from the state diagram before the projection welding shown in FIGS. The positioning allowance for the positioning projection 4c to fit into the positioning hole 3c of the shoe rim 3 is increased by the height of the welding projection 3b of the shoe rim 3, and the tip of the positioning projection 4c reaches near the shoe rim 3 surface. Compared to the conventional case, the cost increases significantly.
In addition, since protrusion welding is the same as before, the description thereof will be omitted in the following.
[0017]
Accordingly, the operator can visually check the front end of the positioning projection 4c from the front, or the positioning hole 3c can be used for positioning the shoe web 4 only by moving the shoe rim 3 slightly from side to side. A sensory judgment as to whether or not it is fitted to the protrusion 4c becomes very clear, so that workability is improved and erroneous work can be completely prevented.
In addition, the formation of the protrusion 3d for increasing the allowance and the positioning hole 3c can be performed simultaneously with the projection of the welding protrusion 3b and the opening of the pilot hole (not shown), so that the processing is also simple. Moreover because can be secured hanging or Ri allowance of R bent when the inner R is for positioning the shoe web 4 be somewhat smaller projection 4c and the shoe rim 3 holes 3c for positioning the shoe rim 3, also simplified the process However, even if a slight misalignment occurs between the upper and lower electrodes, there is no concern about the circumferential displacement of the shoe rim 3.
In addition, since the protrusion 3d for increasing the allowance is also welded at the time of the protrusion welding, the overall welding strength can be improved, and the number of the original welding protrusion 3b can be reduced.
Furthermore, since the protruding portion 3e formed on the shoe rim 3 can limit the displacement in the width direction of the shoe rim 3 with respect to the shoe web 4, it is used as a means for preventing the displacement in the width direction of the shoe rim 3 that has been conventionally installed in the welding jig. There is also an advantage that the structure concerned can be simplified.
[0018]
4 and 5 show a second embodiment of the present invention, which is a modification of the positioning protrusion formed on the shoe rim. 4 is an enlarged view showing a positioning portion in the circumferential direction before the projection welding of the shoe rim 3 and the shoe web 4, and FIG. 5 is a plan view of FIG.
[0019]
The shoe rim 3, with projections 3d for circular takes allowance increases are formed by projections out forming by pressing, in the projection 3d for increasing the costs allowance, the positioning of the rectangle a long shape in the circumferential direction of the shoe rim 3 A hole 3c is formed. In addition, the shape of the protrusion 3d for increasing the allowance is not limited to a circle.
The state in which the positioning projection 4c of the shoe web 4 is fitted in the positioning hole 3c is the same as that of the first embodiment of the invention described above, and the operation and effect thereof are also completely the same, so the description thereof is omitted. To do.
[0020]
6 and 7 show a third embodiment of the invention, FIG. 6 is a front view showing a state before the projection welding of the shoe rim 3 and the shoe web 4, and FIG. 7 is an enlarged view showing the circumferential positioning portion of FIG. It is.
[0021]
The third embodiment is different from the first and second embodiments in the outer shape of the shoe web 4 and the shoe rim 3.
That is, the shoe web 4 is formed with recesses 4d on both sides of the positioning protrusions 4c on the outer peripheral surface thereof, and the protrusions 3d for increasing the allowance formed on the shoe rim 3 are formed in the recesses 4d. Accordingly, the tip of the positioning projection 4c of the shoe web 4 can be protruded from the surface of the shoe rim 3 when the both 3 and 4 are aligned in the circumferential direction.
Further, in place of the welding projection 3b formed on the shoe rim 3 in the first and second embodiments of the invention described above, a plurality of welding projections 4b are formed on the outer periphery of the shoe web 4. It is clear that it is good.
[0022]
As described above, since the tip of the positioning projection 4c of the shoe web 4 protrudes from the surface of the shoe rim 3 in a state where the shoe rim 3 is placed on the welding projection 4b of the shoe web 4, the alignment operation is performed. The visual recognition effect at the time and the positional displacement prevention effect at the time of welding are further improved.
[0023]
【The invention's effect】
Since the present invention has been described above, the following effects can be obtained.
[0024]
<A> Since the positioning hole formed in the shoe rim protrudes toward the outer periphery of the shoe web so that the margin for the positioning projection formed in the shoe web increases, The sense of fitting between the two becomes clear and the workability is greatly improved, and erroneous work can be completely eliminated.
<B> Since the allowance between the positioning hole and the positioning projection is large, the circumference of the shoe rim can be improved even when the inner radius R of the shoe rim is slightly small or the upper and lower electrodes are slightly misaligned. It is very economical because there is no need to worry about direction deviation, and there is no need to sort out good products.
<C> Since the positioning projections formed on the shoe rim can be used as welding projections, the overall welding strength can be improved.
<D> By forming a means for limiting the displacement in the width direction of the shoe rim with respect to the shoe web in the circumferential positioning protrusion formed on the shoe rim, the welding jig structure can be simplified.
<E> The positioning projections and holes formed on the shoe rim and the positioning projections and depressions formed on the shoe web can all be incorporated into the conventional press progressive molding, and the processing is simple.
[Brief description of the drawings]
FIG. 1 is a front view showing a state of a shoe rim and a shoe web before projection welding according to a first embodiment of the invention.
FIG. 2 is an enlarged view showing a circumferential positioning portion in FIG. 1;
FIG. 3 is a plan view of FIG. 2;
FIG. 4 is an enlarged front view showing a state of the circumferential positioning portion according to the second embodiment of the present invention before projection welding.
FIG. 5 is a plan view of FIG. 4;
FIG. 6 is a front view showing a state of a shoe rim and a shoe web before projection welding according to a third embodiment of the invention.
7 is an enlarged view showing a circumferential positioning portion of FIG. 6;
FIG. 8 is a front view showing a state before the projection welding of a conventional shoe rim and shoe web.
9 is an enlarged plan view showing a positioning part of the shoe rim of FIG. 8. FIG.
FIG. 10 is a plan view showing a modification of the positioning part of the shoe rim of FIG.
FIG. 11 is a front view of a conventional brake shoe.
[Explanation of symbols]
2 Brake shoes
3 Shoe Rim
3b Weld protrusion
3c Positioning hole
Protrusions for increasing 3d allowance
3e Projection
4 Shoeweb
4b Welding protrusion
4c Protrusion for positioning
4d hollow
5 Brake lining
6 Upper electrode

Claims (4)

A shoe rim of the brake lining on the outer circumferential surface is fixed, the brake shoes of the drum brake comprising a shoe webs are integrated by a plurality of projections welded to the inner circumferential surface of the shoe rim,
A positioning hole drilled in the shoe rim, and a protrusion for increasing the allowance, which is arranged facing the circumferential direction by causing the peripheral edge of the positioning hole to protrude toward the outer peripheral surface of the shoe web. A positioning protrusion formed on the shoe web and entering the positioning hole between the protrusions for increasing the allowance ;
Brake shoes for drum brakes. In Claim 1, The protrusion part was formed in the both sides of the direction orthogonal to the circumferential direction of the protrusion for the said hook allowance increase, and the width direction shift | offset | difference of the shoe rim with respect to the said shoe web was restrict | limited. ,
Brake shoes for drum brakes. In Claim 1, a depression is formed on both sides in the circumferential direction of the positioning projection formed on the shoe web, and the projection for increasing the allowance is immersed in the depression .
Brake shoes for drum brakes. In any one of Claim 1 thru | or 3, the protrusion for the circumferential direction hook allowance protrudingly provided in the said shoe rim at the time of the projection welding of the said shoe rim and a shoe web is welded simultaneously .
Brake shoes for drum brakes.

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