JP2002098182A - Manufacturing method for disc brake pad and pad manufactured by the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method capable of manufacturing a disc brake pad without loosing an adhesive layer formed on the front face of a back plate and also without producing burrs of the adhesive formed thereat. SOLUTION: A spacer 4 of which the thickness is heavier than that of the back plate 11 is interposed between an insert 1 for setting the back plate 11 and a die 3. The adhesive layer formed on the surface of the back plate 11 is prevented from being lost caused by a die pressure, and a trouble is prevented to occur at the adhesive layer by avoiding the contact of the back plate 11 and the die 3 using the spacer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pad used for a disc brake for a vehicle or an industrial machine, in which the adhesive layer provided on the surface of the back plate disappears and the adhesive protrudes to the outer periphery of the back plate. The present invention relates to a method of manufacturing a disc brake pad that can be manufactured without performing the method, and a pad manufactured by the method.

[0002]

2. Description of the Related Art A general disc brake pad is composed of a back plate provided with an adhesive layer on the front surface and a raw material or a preform of a friction material (lining) in a thermoforming mold including a die. It is manufactured through a process of heating and pressing. The heating and pressurizing are performed to form and bond the friction material. If burrs of the friction material and the adhesive are generated in this step, an extra deburring step is required.

In view of the above, a manufacturing apparatus and a back plate structure for eliminating the generation of burrs are disclosed in Japanese Patent Application Laid-Open No.
No. 13236.

[0004] The manufacturing apparatus disclosed in the former publication is shown in FIG.
As shown in the figure, on the upper surface of the die (referred to as a frame type) 3,
A convex portion 9 is provided in contact with the back plate 11 placed on the die in line contact or near line contact, and the convex portion forms a raw material of a friction material or a preformed product (temporarily formed product) in the cavity (cavity) of the die. The raw material and the pieces of the preform that fall on the upper surface of the die when they are inserted are tightly compressed by the die and the back plate to prevent burrs from adhering to the surface of the back plate.

The back plate proposed in Japanese Utility Model Laid-Open No. 13236/1987 prevents the adhesive layer provided on the front surface from becoming burrs and protruding to the outer periphery of the back plate. According to the pad manufacturing method disclosed in the publication,
Contrary to the method of No. 67696, the back plate is set on the lower side of the die, the lower plate is closed with the lower opening of the die, and in this state, the raw material of the friction material and the preform are put inside the die and added. Since the pressure is applied, it is extremely unlikely that the raw material or the like adheres to an unintended position on the back plate and forms burrs. However, in this method of setting the back plate below the die, as shown in FIG.
A part of the adhesive layer 13 provided on the front surface of the die 1 is in contact with the die 3 and is melted by the heat of the die, which is crushed by the die at the time of pressurization and protrudes to the outer peripheral portion of the back plate to become burrs. In order to prevent burr of the adhesive, Japanese Utility Model Application Laid-Open No.
In No. 36, a chamfered portion C is provided on the outer peripheral edge of the back plate to allow the adhesive extruded from between the die and the back plate to escape there. .

[0006]

Problems to be Solved by the Invention JP-A-2000-167
The technique of No. 696 is not preferable in terms of cost because the die has a special shape and the mold cost is high, and the mold life is shortened due to wear and pain of the projection.

[0007] Further, since the convex portion provided on the die is pressed against the back plate in a state of or near line contact, the adhesive layer on the front surface of the back plate is cut off, and the rust prevention of the back plate by the adhesive layer is reduced. Not done effectively.

Further, in the prior art disclosed in Japanese Patent Application Laid-Open No. 2000-167696, the outer peripheral portion of the front surface of the back plate is pressed against the die. In this case, not only the friction material material dropped on the die, but also the adhesive layer on the back plate surface is pressed, and the adhesive layer is melted by the heat of the die and crushed to form burrs on the outer periphery of the back plate. Protrude.

The technique disclosed in Japanese Utility Model Laid-Open No. 13236/1987 also requires chamfering the back plate of each pad, which is not preferable in terms of productivity and cost.

When the back plate is set under the die,
As shown in FIG. 5, the adhesive layer 13 on the outer peripheral portion of the back plate is melted by the heat of the die, and is pressed by the die 3 and extruded from between the back plate 11. The adhesive layer in the area where the material does not ride cannot be used as a rust preventive film on the back plate.

For this reason, before forming an adhesive layer, a rust-preventive film which does not disappear even when heated and pressed is separately provided on the surface of the back plate.
It is not preferable to increase the number of steps.

Therefore, the present invention prevents the adhesive layer on the back plate surface from protruding to the outer periphery and forming burrs.
It is an object of the present invention to provide a method of manufacturing a disc brake pad which leaves the adhesive layer intact after bonding a friction material and is used as a rust preventive film on a back plate, and to provide a pad manufactured by the method. .

[0013]

In order to solve the above-mentioned problems, in the present invention, a back plate provided with an adhesive layer on its surface, a raw material of a friction material or a preform are heated by a thermoforming mold.
In the step of pressing and forming and bonding, the die for forming the friction material of the thermoforming die and the back plate set at the lower or upper part of the die are brought into a non-contact state at the end point of pressing, and Heating and pressing are performed by setting the gap between the plates to a size that prevents the friction material from protruding.

While the die and the back plate are kept in a non-contact state during heating and pressing, it can be realized by controlling the position of the die and the back plate holding member. However, this method requires an expensive manufacturing apparatus. Therefore, it is preferable to perform the operation between the die and the back plate holding member or the back plate pressing member of the thermoforming mold with a spacer or the like thicker than the back plate outside the friction material.

In this case, the thickness of the adhesive layer is set to the maximum thickness in consideration of the allowable dimensional variation of the back plate in order to keep the non-contact state between the die and the back plate while preventing the friction material from protruding. It is preferable that the thickness is equal to the sum of the thicknesses.

In order to reduce the cost, it is preferable that the spacer and the like also serve as a positioning member for the back plate.

The same effect can be obtained by providing a die or a back plate holding member with a convex contact portion having a height higher than the thickness of the back plate outside the back plate instead of providing the spacer.

The pad manufactured by this method has an adhesive layer which has been dried and solidified intact on the surface of the outer peripheral portion of the back plate which is outside the adhesion area of the friction material.

[0019]

According to the method of the present invention, heating and pressurizing are performed while the die and the back plate are not in contact with each other.
No pressure is applied, so that the adhesive layer on the surface of the back plate is not extruded from between the back plate and the die, and no burr of the adhesive is generated.

In the pad manufactured by this method, the adhesive layer on the outer peripheral surface of the back plate is left intact, and the adhesive layer functions as a rust-preventive film.

When the die is separated from the back plate, there is a concern that the friction material may protrude into the gap between the two. However, the raw material constituting the friction material includes fibrous substances and inorganic particles in addition to resin. Since these materials are mixed and the raw material is difficult to flow, the protrusion does not occur in a small gap, and good molding can be performed even in a non-contact state.

[0022]

FIG. 1 shows a first embodiment of the manufacturing method of the present invention. In FIG. 1A, reference numeral 1 denotes an insert holding the back plate 11, reference numeral 2 denotes a punch facing the insert 1, and reference numeral 3 denotes a die. These components constitute a thermoforming die. The insert 1 is held by a fixing member (not shown), does not move, and has a punch 2 having a pressing mechanism (not shown).
Is raised and lowered to apply pressure.

Although the die 3 has an elevating mechanism (also not shown), the die 3 itself is not pressed downward,
During pressurization by the punch 2, it is placed on the lower member by its own weight.

On the insert 1, a spacer 4 also serving as a positioning member for the back plate is incorporated. The spacer 4
Is thicker than the back plate 11 and supports the die 3 that has descended. At this time, the die 3 is attached to the adhesive layer 1 on the back plate surface.
3 (see FIG. 3).

The thickness t of the spacer 4 is equal to or greater than the value obtained by adding the thickness of the adhesive layer 13 of FIG. By setting the value obtained by adding the thickness of the adhesive layer to the maximum thickness of the back plate to the thickness of the spacer 4, the non-contact state between the die 3 and the back plate 11 can be maintained. The back plate 11 is set on the insert 1 by positioning with the spacer 4, and the die 3 is placed in the state shown in FIG.
The raw material 12a (which may be a preformed product) of the friction material is put in the inside, and pressurization by the punch 2 is performed as shown in FIG.

FIG. 2 shows a second embodiment of the manufacturing method of the present invention. The thermoforming mold used in this method includes a die 3,
The lower punch 5 is inserted into the die 3 and the upper punch 6 faces the lower punch 5. The die 3 is supported by a cylinder 7. The upper punch 6 in FIG. 2C has a movable ram structure, and the upper punch 6 is lowered to apply pressure. At this time, the die 3 is pushed up by the cylinder 7, and is pushed down by the upper punch 6 from a position pushed up by a force stronger than the pushing force of the cylinder 7. In the method of FIG. 2, the raw material 12a of the friction material and the preform are put into the die 3 into which the lower punch 5 is inserted.
As shown in FIG. 2B, the back plate 11 is
The pressing is performed by the upper punch 6 as shown in FIG.

In the method shown in FIG. 1, the insert 1 or the die 3 is provided. On the other hand, in the method shown in FIG. The state may be maintained.

Hereinafter, a specific example of the method of FIG. 1 (Example 1)
2 and a specific example (Example 2) of the method of FIG.

Example 1 A solution of a phenol resin was applied to the front surface of a back plate made of an iron-based material SAPH (hot-rolled steel plate for an automobile structure) so as to have a thickness of about 10 μm after drying. 30 in the furnace
Dried for minutes. Under this condition, the resin film formed on the surface of the back plate 11 has adhesiveness, and becomes the adhesive layer 13 in FIG.

Next, the back plate 11 on which the adhesive layer was formed was positioned and set on the insert 1 with the spacer 4, and the die 3 was overlaid on the spacer 4. The spacer 4 used had a thickness of the average thickness of the back plate + 0.25 mm.

Thereafter, as shown in FIG.
The raw material 12a of the friction material is put in the
And pressed. The condition at this time is that the mold temperature 16
0 ° C., pressure 10 MPa, pressurization time 10 minutes. In this step, the adhesive layer 13 of FIG. 3 melts, and the compressed raw material and the back plate 11 are bonded.

The friction material raw material 12a is composed of 30% steel fiber, 10% glass fiber, and 1% aramid fiber by weight.
0%, phenol resin 20%, barium sulfate 10%, copper powder 10%, friction dust 10% were used, but this is only an example.

The molded body obtained through the above steps was subjected to a heat treatment at 200 ° C. for 10 hours in the next step, and further subjected to painting and polishing in a finishing step to obtain a disc brake pad of the product.

As shown in FIG. 4, the pad has no trace of the adhesive layer 13 outside the friction material 12 being pressed by the die, and the adhesive layer 13 in that region remains intact. Was. In addition, no burr of the adhesive was generated.

Example 2 As in Example 1, the thickness of the spacer 4 was set to (average thickness of the back plate +
0.25 mm), and heating and pressurization were performed by the method of FIG. 2 using the same back plate and friction material as in Example 1. The disc brake pad of the product was obtained under the same conditions and the subsequent steps as in Example 1.

In the pad, the adhesive layer outside the friction material was left intact and there was no adhesive burr.

In the method shown in FIG. 2, the back plate 1 is placed on the die 3, but the adhesive layer of the back plate needs only to be lightly loaded by the weight of the back plate. Before the back plate is set, the input of the raw material is finished, and since the time from the mounting of the back plate to the pressurization is short, the back plate 11 is pressed by the raw material before the adhesive is melted and rises from the die 3, It is considered that the adhesive layer was left intact.

From the results, the method of the present invention is shown in FIG.
It can be seen that both methods shown in FIG. 2 are effective.

Example 3 SAPH as a material of the back plate is, for example, 4.00 to 5.0.
For a 0 mm-thick one, the tolerance specified in JIS G3113 is ± 0.24 mm. The thickness of the spacer 4 was set to (average thickness of the back plate + 0.25 mm) in Examples 1 and 2 by adding a thickness of the adhesive layer of 10 μm to this. Board 11
A gap of up to about 0.5 mm occurs between them.

Then, the back plate was adjusted to have a minimum thickness to form a gap of 0.5 mm between the die 3 and the back plate, and the state of the friction material protruding into the gap was examined.

As a result, in both the method of FIG. 1 carried out under the same conditions as in Example 1 and the method of FIG. 2 carried out under the same conditions as in Example 2, the protrusion of the friction material is such that only a trace which can be recognized only when enlarged with a magnifying glass. However, it was confirmed that it was possible to keep it within a sufficiently acceptable range.

[0042]

As described above, in the present invention, a gap is formed between the die and the back plate within a range in which the friction material does not protrude, and heating and pressing for forming and bonding are performed. The adhesive layer on the surface remains intact and no burr of the adhesive occurs.

Further, the adhesive layer on the outer peripheral surface of the back plate exposed in the area surrounding the friction material after pressing is left intact,
In the subsequent heat treatment step, the adhesive layer hardens and acts as a rust-preventive film on the back plate.

The coating in the pad finishing step is performed for the purpose of preventing rust on the back plate, and the work is often sprayed with a spray from the back side of the back plate, and the front surface of the back plate which is shaded at this time is often used. May not be sufficiently painted. In such a case, the adhesive layer left intact works particularly effectively as a rust preventive film.

In addition, the use of spacers to keep the die and the back plate out of contact does not require expensive manufacturing equipment. In addition, since the dimension of the originally required positioning member for the back plate can be changed and used as a spacer, there is no increase in the number of mold components and the cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is a process chart of a manufacturing method according to a first embodiment.

FIG. 2 is a process diagram of a manufacturing method according to a second embodiment.

FIG. 3 is an enlarged sectional view showing a part of a back plate provided with an adhesive layer.

FIG. 4 is a plan view of a pad manufactured by the method of the present invention.

FIG. 5 is a diagram showing a state in which the adhesive layer on the surface of the outer peripheral portion of the back plate has disappeared by a conventional method.

FIG. 6 is a cross-sectional view of the apparatus disclosed in JP-A-2000-167696.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insert 2 Punch 3 Die 4 Spacer 5 Lower punch 6 Upper punch 7 Cylinder 8 Back plate positioning member 9 Convex part 11 Back plate 12 Friction material 12a Friction material raw material 13 Adhesive layer

Claims (4)

[Claims] In a step of heating and pressing a raw material or a preform of a friction material with a thermoforming mold to form and adhere a backing plate provided with an adhesive layer on its surface, a friction material of a thermoforming mold. The molding die and the back plate set on the lower or upper part of the die are brought into a non-contact state at the end point of pressurization, and the gap between the die and the back plate is heated to a size that prevents the protrusion of the friction material. And a method for producing a disc brake pad. 2. A spacer thicker than the back plate outside the back plate or between the die and the back plate holding member or the back plate pressing member of the thermoforming mold, or holding the die or the back plate. 2. The method for manufacturing a disc brake pad according to claim 1, wherein the member is provided with a convex contact portion having a height higher than the thickness of the back plate to maintain a non-contact state between the die and the back plate. 3. The method for manufacturing a disc brake pad according to claim 2, wherein heating and pressurizing are performed by positioning a back plate with the spacer or the convex portion. 4. A friction material is adhered to the surface of the back plate, and the dried and solidified adhesive layer is left intact on the surface of the outer peripheral portion of the back plate which is out of the adhesion area of the friction material. A disc brake pad manufactured by any one of the above methods.