JPS626342Y2 - - Google Patents

Description

[Detailed description of the invention] In this invention, in a drum brake for vehicles equipped with a parking brake mechanism, the parking brake mechanism is attached to a bucking plate that supports the components of the drum brake such as a pair of brake shoes and anchors. In particular, regarding the mounting device for rotatably mounting the bell crank lever, which is a part of the
This invention relates to a device for penetrating and attaching a backing plate.

Drum brakes for vehicles are often equipped with a mechanical parking brake mechanism, which includes an operating lever that applies (expands) the brake shoe directly in response to input from a parking brake operating device, or a lever that directly applies (expands) the brake shoe based on input from the parking brake operating device, or a lever that directly applies (expands) the brake shoe based on the input from the parking brake operating device. The bell crank lever, which serves as a means of transmitting force, such as a relay lever that relays to the user, is rotated by a pin while protruding into the inside of the plate where the brake shoe, etc. is installed through the elongated hole formed in the bucking plate. Many types are movable.

In that case, the inner ends of these levers are linked directly to the brake shoe if it is an operating lever, or indirectly linked to the brake shoe if it is a relay lever, while the inner ends of these levers are connected to the outer end extending outside the bucking plate. The end portion will be connected to the operating device via a cable or the like. Therefore, based on the input applied to the outer end of the lever and the reaction force from the brake shoe applied to the inner end, a force in the direction of the resultant force is exerted on the pivot center of the lever.

Conventionally, in a device for attaching such a bell crank lever to a bucking plate, a bracket made of die-casting or the like is fixed to a portion surrounding the elongated hole on the outer surface of the bucking plate, and an insertion hole formed in the bracket is fixed to a portion surrounding the elongated hole on the outer surface of the bucking plate. A bell crank lever is inserted into the elongated hole of the bucking plate, and the lever is supported so as to be rotatable around the axis of the pin by a pin provided through the middle part of the bracket and the lever. It was starting to happen.

However, since the resultant force applied to the lever when the parking brake is applied is applied to the bracket through the pin before being received by the bucking plate, the bracket itself is required to have high rigidity and strength to withstand this resultant force. be done.
Therefore, in order to ensure such rigidity and strength, it is necessary to make the bracket thick and large, and it is also necessary to avoid making it heavy. Therefore, the manufacturing cost of the bracket was extremely high.

Furthermore, when fixing the bracket to the bucking plate, it is necessary to ensure high mounting strength to withstand the bending moment generated by the lever on the bracket. There were also inherent problems.

The present invention was developed against the background of the above-mentioned circumstances, and its purpose is to insert the bell crank lever as described above into the inside of the slotted hole formed in the bucking plate. When attaching the bracket rotatably using a bracket and a pin, the strength required for the bracket is smaller than that of the conventional method, and the bracket is formed using an inexpensive processing method mainly using press working. The object of the present invention is to provide a simple and inexpensive lever mounting device.

The gist of the present invention, which was made to achieve this purpose, is as follows: (i) By bending a single steel plate, a pair of side walls facing each other and a connecting portion connecting the side walls are formed. to form a bracket having a shape including a U-shaped portion, and a portion of the bracket near the connecting portion is attached to the inner surface of the bucking plate so that the pair of side walls are parallel to the elongated hole of the bucking plate. Fix it. (ii) This bracket has a pair of side walls on mutually opposing portions.
A pair of U-shaped notches are formed in the side wall portions from the edge on the backing plate side to the edge on the opposite side. A pivot shaft that passes through the middle part of the bell crank lever inserted between the side walls through the elongated hole and rotatably supports the lever in a plane parallel to the side walls is attached to the bottom of the pair of notches. The outer circumferential surface of both ends of the pivot shaft, which extends outward from the side walls, is supported by the inner surface of the bucking plate, so that when the parking brake is applied, the lever is A component of the applied force in the direction toward the outside of the backing plate is received by the inner surface of the backing plate via the pivot shaft. (iii) Furthermore, the bracket is provided with a pair of protrusions that protrude from each of the pair of side walls toward the outside of the bucking plate, and these protrusions are fitted into the long holes of the bucking plate; Engaging the projection with one end of the elongated hole, in other words, one end of the elongated hole that faces the direction of action of the longitudinal component of the force applied to the lever when the parking brake is applied. As a result, the force exerted by the lever on the bracket is received at one end of the elongated hole through the protrusion.

With the above configuration, the lever component in the direction toward the outside of the bucking plate can be directly received by the bucking plate without being transmitted to the bracket, and on the other hand, the lever component in the longitudinal direction of the long hole in the bucking plate can Although the force is initially transmitted to the bracket, it is immediately received by the bucking plate via the protrusion. In this way, the force that acts on the center of rotation of the lever when the brake is applied is dispersed into a component that is received directly by the bucking plate and a component that is received indirectly via the bracket, avoiding concentration of load on the bracket. In addition, since the force transmission path to the bucking plate is shortened, the bracket is not required to have such high rigidity and strength. Therefore, it is possible to make the bracket thinner and smaller, and even one made of sheet metal can perform a sufficient function.

By using a manufacturing process that mainly involves stamping, bending, etc. from steel sheet material, which is essentially cheaper than casting, the cost of the bracket itself is lower than that of conventional die-casting products. It is reduced by about 50 to 60% compared to the previous year. Moreover, the formation of the protrusions and notches is easy.

Furthermore, when fixing the bracket to the bucking plate, it can be said that the force applied to the lever is not substantially transmitted to the fixed part, so even if it is not firmly fixed, it is necessary to prevent the bracket from moving. It is sufficient to secure the bracket with sufficient mounting strength, so a simple fixing means is sufficient for the bracket, and the bracket can be easily attached.

Hereinafter, an embodiment in which the present invention is applied to a relay bell crank lever mounting device that relays input from a parking brake operating device to a brake shoe will be described with reference to the drawings.

In FIG. 1, reference numeral 2 denotes a backing plate, and an annular dust cover 4 is fixed to the outer surface of its peripheral edge. Inside the buckling 2, there is a pair of brake shoes (shoe assemblies) 6, only one of which is shown, and an anchor (not shown),
Components of the drum brake such as wheel cylinders are provided, and shoe extension devices such as an operating lever and a parking strut, which constitute a part of the parking brake mechanism, are provided, and these are supported by the bucking plate 2. ing.
The bucking plate 2 is formed with a substantially rectangular long hole 10 through which the bell crank lever 8 for relay passes, and a portion of the inside of the bucking plate 2 corresponding to the long hole 10 is made of steel plate. A bracket 12 is provided.

As shown in FIG. 2, the bracket 12 is formed by a single press process, and is made by punching a steel plate into a predetermined shape and bending it into a long U-shape. It includes a pair of parallel side wall portions 14 and a curved connecting portion 16 that connects the side wall portions 14 at the base end. As is clear from FIG. 1, the bracket 12 is in a state where the side wall portion 14 and the connecting portion 16 are perpendicular to the inner surface of the bucking plate, and the pair of side wall portions 14 are arranged along both side edges of the elongated hole 10. It is fixed to the inner surface of the bucking plate 2 by bolts 18 and nuts 20 in a state parallel to its longitudinal direction. The bolt 18 is inserted between the side walls 14 near the connecting portion 16 and protrudes outward through a bolt hole 22 formed in the bucking plate 2, into which the nut 20 is tightened. Therefore, one end surface of each of the connecting portion 16 of the bracket 12 and the side wall portion 14 in the vicinity thereof is brought into close contact with the inner surface of the bucking plate 2, and the head of the bolt 18 is attached to the bracket via the washer 24 or the like. 12 is seated on the other end surface. The portion of the bracket 12 near the connecting portion 16 is
In order to form a seat for the bolt 18, the height from the inner surface of the bucking plate 2 is made lower than other parts.

As is clear from FIG. 4, the distance between the both sides 14 of the bracket 12 is set to be slightly smaller than the width of the elongated hole 10, and the bracket 12 has two holes as shown in FIGS. 1 and 2. , long hole 10
A pair of protrusions 26 are provided from each of the side wall portions 14 of the portions corresponding to the backing plate 2, which protrude toward the outside of the backing plate 2 with reference to the inner surface of the backing plate 2. These protrusions 26 are formed integrally and continuously with each side wall portion 14 so as to face each other in parallel, and are arranged in parallel to the elongated holes 10 of the bucking plate 2.
At the same time, one side edge of each of both protrusions 26 is engaged with the end of the elongated hole 10 on the side of the bracket connecting part 16. Therefore, long hole 10
The force acting on the bracket 12 in the longitudinal direction toward the connecting portion 16 is received at one end of the elongated hole 10 via the protrusions 26 and transmitted to the bucking plate 2.

The other side edge of both protrusions 26 is slightly spaced apart from the other edge of the elongated hole 10, so that the protrusion 26, which is formed long along the elongated hole 10, especially the part on the side of the connecting portion 16, has a The entire outer surface of each projection 26 is in contact with both side edges of the elongated hole 10 over almost the entire length thereof, as shown in FIG. Therefore, the protrusion 26 also functions to position the bracket 12 in the width direction of the elongated hole 10.

Note that by forming a rounded portion 28 that extends outward in the width direction as shown in FIG. 4 at the corner of the elongated hole 10 where the projection 26 engages, stress concentration at that corner is avoided and the projection This means that the side edges of 26 and one end of the elongated hole 10 can engage with each other on a plane-to-plane basis.

The bracket 12 further includes figures 1 and 2.
As is clear from the figure, in the mutually opposing portions of the pair of side wall portions 14, from the edge of the side wall portion 14 on the bucking plate 2 side toward the edge on the opposite side,
A pair of U-shaped notches 30 are provided. Note that these notches 30 can be seen as being formed from the tips of the protrusions 26 to the side wall portions 14, but if we consider that the protrusions 26 protrude from each of the side wall portions 14 across the notches 30, , the expressions above apply. Those pair of notches 30
are formed with a constant width and depth at positions facing each other in the longitudinal center of the elongated hole 10, and the bottom of each notch 30 has a semicircular cylindrical surface shape.

Such a U-shaped notch 30 in the bracket 12
Furthermore, the above-mentioned protrusion 26 is easily formed by punching out the side wall portion 14 and the corresponding portions from a steel plate material by punching press work, and then bending the same as described above.

A pivot shaft 32 spans between the side walls 14 of the bracket 12 so as to be substantially in contact with the bottom of each of the notches 30. The pivot 32 passes through the middle part of the bell crank lever 8 inserted between the side walls 14 through the elongated hole 10 of the bucking plate 2, and rotates the lever 8 within a plane parallel to the side walls 14. It is supported rotatably around the axis.

As shown in FIG. 3, the pivot 32 is fitted in a shaft hole 33 formed in the lever 8 so as to be relatively rotatable, and has a pair of annular grooves 34 having a rectangular cross-section on both sides of the central fitting part. It is equipped with That is, each groove 34 has a notch 30 in the bracket side wall 14.
The edges of the grooves 34 are engaged with each other, and the bottom surfaces of the grooves 34 are brought into substantially contact with the bottoms of the notches 30. Both end portions of the bracket 12 protrude outward from both side wall portions 14, in other words, the annular groove 34.
The cylindrical outer circumferential surface of the head 36 formed on the outside of the pivot plate 2 is brought into contact with the inner surface (edge) near the elongated hole 10 of the backing plate 2, so that the pivot 3
2 is supported by the bucking plate 2.

Therefore, even if a force is applied to the pivot shaft 32 in a direction toward the outside of the backing plate 2, that force is directly received by the inner surface of the backing plate 2 without going through the bracket 12.

Further, by the engagement with the annular groove 34 of the pivot shaft 32 of the bracket side wall portion 14, the both side wall portions 14 are prevented from opening, and the outer surfaces of the pair of protrusions 26 are brought into contact with both side edges of the elongated hole 10. Coupled with this, the rigidity in the width direction of the elongated hole 10 of the bracket 12 is increased. It also serves to prevent the shaft 32 from coming off.

In addition, regarding the pivot 32, the pivot has a large diameter part at the center and small diameter parts on both sides. It is also possible to support it on the inner surface of 2. In addition, when the fitting part with the lever 8 becomes a sliding surface, the outer circumferential surfaces of both supported ends do not necessarily have to be circular, and the outer circumferential surface of a rectangular, hexagonal, etc. You can also do it. Furthermore, depending on manufacturing considerations, the pivot 32 and the lever 8 may be unrotatably integrated or integrally formed.

The lever 8, which is rotatably supported by the pivot 32 as described above, has a hook-shaped inner end that projects into the inside of the bucking plate 2 through the elongated hole 10.
It is connected to the brake shoe 6 via a shoe extension device such as a cable 38 and an operating lever, while the outer end of the bucking plate 2 extending outward is connected to a parking brake operating device via a cable 40 or the like. be done. Of course cable 3
8, 40 may be replaced by a connecting rod or the like.

In order to prevent water from entering the inside of the bucking plate 2 through the elongated hole 10, a dust boot 42 is provided, one end of which is placed on the outer surface of the bucking plate 2, and the other end is located between the levers 8. Each is fixed on the outside. 44 is a fixing metal fitting. In addition, since the bracket 12 is provided inside the bucking plate 2, and as a result, it has a structure that prevents water from entering the pivot portion of the lever 2, so if the sealing performance of the dust boot 42 deteriorates to some extent. However, there is an advantage in that it is possible to avoid rusting on the pivot portion of the lever 8.

On the other hand, a forked guide member 46 into which a portion near the outer end of the lever 8 is inserted is fixed to the dust cover 4 to guide the lever 8 as it rotates.

In the device configured as described above, when the operating force applied to the operating device is input to the outer end of the lever 8 and the lever 8 is rotated by a predetermined angle to apply the parking brake, the lever 8 The input a and the reaction force b from the brake shoe are applied to the outer end of the lever 8 and the reaction force b from the brake shoe to the inner end of the lever 8, respectively. A resultant force of the vector sum of reaction forces b acts. A component of the resultant force acting on the lever 8 in the longitudinal direction of the elongated hole 10 in the direction toward the connecting portion 16 of the bracket 14 (hereinafter referred to as the x-direction component) is transmitted to the bracket 14 via the pivot 32. However, the pair of protrusions 26
The signal is received at the end of the elongated hole 10 on the side of the connecting portion 16 through the hole 10, and is transmitted to the backing plate 2 via a short transmission path, albeit indirectly. On the other hand, lever 8
The component force in the direction toward the outside of bucking plate 2 of the resultant force acting on (hereinafter referred to as the y-direction component)
is received directly on the inner surface of the backing plate 2 via the pivot 32 without passing through the bracket 12.

In addition, as shown in the figure, there are many cases in which the input a and the reaction force b act in orthogonal directions and are parallel to each component in the y direction and the x direction, but the shape of the lever 8 This may not necessarily be the case depending on the situation. However, even if the directions of action of the input a and the reaction force b are acute or obtuse, as long as the resultant force applied to the lever 8 is broken down into components in the x and y directions, the force that can be received by the bucking plate 2 The relationship can be discussed in the same way as above.

In any case, the resultant force applied to the lever 8 is distributed by the bucking plate 2 into a portion that is indirectly received and a portion that is directly received,
This prevents the load from being concentrated on the bracket 12, and the strength required for the bracket 12 itself is moderate. Therefore, the bracket 12 made of inexpensive press-formed steel plate is replaced with the conventional expensive cast bracket. It has become possible to perform sufficient functions comparable to Moreover, bracket 12
Since the force applied to the lever 8 is not substantially transmitted to the fixed part of the bolt 18 (it was previously received at one end of the elongated hole 10 via the protrusion 26), no shearing force is applied to the bolt 18, and , the fixing (mounting) strength of the bracket 12 is
It is sufficient to prevent the backing plate 2 from rattling or coming up from the inner surface of the bucking plate 2. Therefore, the fixing means is only one set of bolts 18 and nuts 20, and the bracket 12 can be fixed easily. .

Incidentally, a specific example of a conventional lever mounting device is shown in FIG. 5 for comparison. Parts having the same functions as shown in FIG. 1 are given the same reference numerals to avoid duplication of explanation.

In the figure, the lever 8 is
The lever 8 is supported by a bracket 52 fixed to the outer surface of the lever 8 by an appropriate number of bolts 50 so as to be rotatable about a pivot 54. However, when the brake is applied, the resultant force of the input force a and the reaction force b, which are applied to the outer and inner ends of the lever 8, is directly applied to the bracket 52 through the pivot 54. Therefore, in order to ensure the strength against this, it is necessary to use an expensive and large bracket 52 made by die casting of aluminum or the like.
Regarding the fixing of 2 to the backing plate 2,
In addition, the force transmission path to the plate 2 becomes longer, and the bracket 52 must be firmly fixed so as to withstand the shear stress and bending stress during braking, which not only increases the cost of the bracket 52 itself but also the installation cost.

In comparison, if a mounting device is used as shown in FIG. 1 described above, the drawbacks of the conventional device are completely eliminated, and as a result, a large cost reduction can be achieved. In fact, rough cost calculations have confirmed that a reduction of at least 50% is possible.

Next, another embodiment of the present invention will be described based on FIG. 6.

In this embodiment, the connecting portion 16 of the bracket 12, which has the same shape as that shown in FIG. A pair of protrusions connected to the side ends of the both side walls 14 are fixed in the vicinity of the connecting part 16 by bolts 18 etc. in the same manner as described above, and at the ends of the elongated holes 10 on the side far from the connecting part 16. The side edges of 26 are engaged. Since the other parts are the same as those of the embodiment shown in FIG. 1, they are designated by the same reference numerals, but even in this case, the same functions and effects as described above can be obtained.

Furthermore, instead of the bracket 12 shown in FIG. 2, a bracket having the shape shown in FIG. 7 or 8 may be used.

In the bracket 60 shown in FIG. 7, a pair of opposing side wall portions 14 forming part of a U-shape are each extended in the longitudinal direction, and each extended end is curved inward and welded together by butt welding. According to
A single steel plate is bent into a flat O-shaped closed shape, that is, a shape that includes two U-shaped parts with connecting parts 16 at both ends, and has a second U-shaped part in the center in the longitudinal direction. A pair of notches 30 and a pair of protrusions 26 each having the same shape and function as shown in FIG. 2 are provided.

With such a bracket 60, the rigidity is higher than that shown in FIG. 2, and if space permits, the backing plate 2 shown in FIG. It is fixed at two locations with bolts 18 or the like. Therefore, the reliability of positioning and fixing becomes even higher.

On the other hand, even if it is not fixed at two places, it can be attached to the bracket 12 shown in FIG. 2, like the bracket 62 shown in FIG. , further provided with a pair of engagement protrusions 64 that protrude in the longitudinal direction, and the protrusions 2
In addition to fitting and engaging the elongated holes 10 shown in FIG.
It is also possible to engage the outer surface of the elongated hole 10 (the edge of the elongated hole 10). In this way, the fixation by bolts 18 etc. is reinforced, and the bracket 6
Even if a force is applied to the bucking plate 2 in the direction of lifting it from the inner surface of the bucking plate 2, movement in that direction is reliably prevented.

Note that the fixing means may be strengthened to some extent, such as the bracket 60 shown in FIG.
In cases where movement in the width direction is of little concern, it is not necessarily necessary for the outer surfaces of the pair of protrusions 26 to be in contact with both side edges of the elongated hole 10, and they may be spaced apart. And long hole 1
If the purpose is to receive the component force in the longitudinal direction of 0 at one end, a pair of small projections 66 with a narrow width as shown in FIG. 9 may be provided to achieve this function.

Further, as for the means for fixing the bracket to the inner surface of the bucking plate, it is most preferable to use bolts and nuts, but the method is not limited thereto. A pair of ears are provided, and spot welding is performed at the ears.
Alternatively, it is also possible to form an appropriate number of point-like or linear projections on the end face of the bracket and perform projection welding.

In addition, in the previous explanation, the case where the present invention is applied to a relay bell crank lever was taken as an example, but if the operating lever directly linked to the brake shoe is provided through the bucking plate, The present invention can be similarly applied to bell crank lever mounting devices such as the above.

It goes without saying that the present invention can be implemented with various other modifications without departing from the scope of the claims for utility model registration.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a mounting device according to an embodiment of the present invention, and FIG. 2 is a perspective view of a bracket used therein. FIG. 3 is a cross-sectional view taken in FIG. 1, and FIG. 4 is a partially cutaway view taken in the direction of arrows. FIG. 5 is a front sectional view showing a specific example of a conventional mounting device, and corresponds to FIG. 1. FIG. 6 is a partial front sectional view showing another embodiment of the present invention, and FIGS. 7 and 8 are
FIG. 2 is a perspective view showing different embodiments of the bracket to be used in FIG. 1; FIG. 9 is a partial perspective view showing another form of the projection provided on the bracket. 2: Bucking plate, 6: Brake shoe, 8: Bell crank lever, 10: Long hole, 1
2, 60, 62: Bracket, 14: Pair of side wall parts, 16: Connecting part, 26, 66: Pair of projections, 3
0: Pair of notches, 32: Pivot, 34: Annular groove, 3
6: Head, 64: Engagement protrusion.

Claims (1)

[Claims for Utility Model Registration] A pair of brake shoes, anchors, and other components of a drum brake are provided so as to protrude into the inside of the bucking plate through elongated holes formed in the bucking plate, and A mounting device for rotatably attaching a bell crank lever linked directly or indirectly to the brake shoe to the bucking plate at an end of the buckling plate, the bell crank lever being rotatably attached to the buckling plate at an end thereof, the bell crank lever being connected to the brake shoe directly or indirectly through another member. The connecting portion is bent into a shape including a U-shaped portion including a side wall portion and a connecting portion connecting the side wall portions, and the side wall portion is parallel to the longitudinal direction of the elongated hole. A member whose neighboring portion is fixed to the inner surface of the bucking plate, the member projects from each of the pair of side walls toward the outside of the bucking plate and fits into the elongated hole, and is fitted into the elongated hole. a protrusion that is engaged with either end; and a pair of protrusions formed on mutually opposing portions of the pair of side walls from an edge on the side of the bucking plate to an edge on the opposite side of the side walls. a bracket including a U-shaped notch; and a bracket that spans between the side walls of the bracket in a state in which it is substantially in contact with the bottoms of the pair of notches, and has outer circumferential surfaces of both ends that respectively protrude outward from the side wall. A pivot supported by the inner surface of the bucking plate and penetrating through an intermediate portion of the bell crank lever inserted between the side walls to rotatably support the lever in a plane parallel to the side walls. and when the parking brake is applied, a component of the force applied to the lever in the longitudinal direction of the elongated hole is received at one end of the elongated hole via a projection of the bracket, while a component of the force applied to the lever in the longitudinal direction of the elongated hole is received by one end of the elongated hole. A bell crank lever mounting device for a parking drum brake, characterized in that an outward component force is received by the inner surface of the bucking plate via the pivot shaft.