CA1323979C

CA1323979C - Method for manufacturing a pad for a disk brake

Info

Publication number: CA1323979C
Application number: CA 591667
Authority: CA
Inventors: Masao Inoue; Takeshi Tanikoshi; Katsuhiro Shibata; Choichi Sugawara
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1988-02-23
Filing date: 1989-02-21
Publication date: 1993-11-09
Anticipated expiration: 2010-11-09
Also published as: GB8904192D0; GB2216066B; GB2216066A; DE3905627C2; DE3905627A1

Abstract

ABSTRACT OF THE DISCLOSURE
A method for manufacturing a pad for a disk brake wherein the pad has a back plate and a lining on the back plate and molded by heating and pressing granules, the lining being formed of a plurality of kinds of lining por-tions which are secured to a plurality of areas set on one surface of the back plate, the method comprising charging granules for the respec-tive lining portions into areas which are defined in a mold-ing frame by a partitioning plate means so as to correspond to the areas set on the back plate, removing the partition-ing plate means from the molding frame, subjecting the granules in the molding frame to a pressing treatment at which the granules are pressed against the back plate which is disposed so as to close an opening end of the molding frame, subjecting the granules also to a heating treatment, and securing the molded lining portions to the back plate.
surface.

Description

:~32397~

The present invention relates tv a method for manufacturing a pad for a disk brake in which plural kinds of lining portions molded by heating and pressing granules are secured to a plurality of areas set in one surface of a back plate.

In the past, such a method of manufacture has been well known~ for example, ~rom Japanese Patent Application Laid-Open No. 252,925/1986. However, in the above-described prior art, a plurality of lining portions which have been molded in advance are secured to one surface of a back plate, and joining between the adjacent lining portions is not satisfactory, posing a problem in terms of strength at the boundary areas.

According to the present invention, there is provided method for manufacturing a brake body for a disk brake, said body having a flat back plate and a lining on said back plate as friction lining, with at least two lining portions having different friction characteristics, the method comprising the following steps- charging certain amounts of granulated materials, allocated to the different lining portions, into a moulding frame having a partitioning device separating the different lining portions from one another; simultaneously moulding all lining portions on said back plate by pressure treatment; and conducting heat treatment, under pressure, of all lining portions on said back plate.

In preferred embodiments, the invention provides:

The above method, wherein said molding consists of a pre-molding step and a main-molding step.

. , .,~ , . ..

1323~7~

~ he above method, wherein said pre-moldin~ step and said main-molding step are executed in a molding frame.

The above methods, wherein as the granulated m~terials for the lining, one containing the ~ollowing components is used:

fibres, lubricants, oxides, non-oxides, loading agents, bonding materials.

The immediately above method, wherein as the granulated material one additionally ~ontaining caoutchouc or cashew-flour is used.
i ~ he above method, wherein as the granulated material for the lining, one containing the following components i5 used:

fibres, lubricants, metal powder, abrasivest loading agents, bonding materials.

The above method, wherein for at least one lining portion, forming the main part of the lining surface of the lining, such granulated material is used, that said lining portion secures a sufficient braking force and that for at least one other lining portion, forming an edge portion o~
the lining surface, such granulated material is used, that said other portion hardly damages the brake disk.

The immediately above methodl wherein the amount of abrasives, contained in the granules for the other lining portion, is reduc~d as compared to the granulated lining material for said one lining portion; and wherein the share i A, .;
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of lubricants in the granulated material for said other lining portion is more than the share of lubricants in said granulated material for said one lining portion.

The present invention will become apparent from the ensuing description of the preferred embodiments in connection with the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional side view of a ' 20 _ 3 _ i, :. .. , . ~ .

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~323~7~

disk brake to which are attached pads manufactured accord-ing to the method o the present invention;
FIG. 2 is a front view of the pad shown in FIG, l;
FIGS. 3(a) to 3(e) are explanatory views successively showing the steps for manufacturing the pad for a disk brake;
FIG. 4 is a longitudinal sectional side view of a disk brake to which are attached modified inner and outer pads manufactured by the method of the present invention;
FIG. 5 is a partially cutaway front view as viewed in a direction of arrow V in FIG. 4;
FIG. 6 is a plan view of the entire pad, ~aken on line VI-VI of P'IG. 4;
FIG. 7 is a plan view showing an arrangement of two pads relating to a rotar~ disk;
FIG. 8 is an entire plan view showing another modified example of an inner pad for a disk brake manufactured according to the method of the present invention;
FIG. 9 is an entire plan view showing an outer pad used in the paired relation with the inner pad shown in FIG. 8;
FIG. 10 is an entire plan view showing a further modified example of an inner and outer pad for a disk brake manufactured by the method of the present invention;
FIG. 11 is a view taken in a direction of arrow XI
in FIG. 10: ~nd ... .

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FIG. 12 is an explanatory view of the operation of a conventional disk brake.

One embodiment of the method according to the present invention will be described hereinafter with re~erence to the drawings. Prior to the description of the method according to the present invention, pads ~or a disk brake manufactured accord.ing to the method of the present invention and a disk brake to which are attached the aforesaid pads will ~irst be roughly described. Referring to FIGS. 1 and 2, a pair of opposed rotary di~ks 1 and 2 are spaced apart ~rom each other and are connected by means of a plurality of connecting portions 3. One rotary disk 2 is integrally provided with a support portion 4 which is mounted on a rotary b.ody to be braked, for example, a wheel of a vehicle.

A aaliper body 5 oP a disk brake Br i5 arranged so as to ~tride over both the rotary disks 1 and 2, and pads 6 and ~
are disposed on the caliper body 5 and more speciically on mutually opposed side surfaces of the rotary disks 1 and 2.
The caliper body 5 is equipped therein with a piston (not shown) which is capable of moving toward and away from the rotary disks 1 and 2 so that during braking one pad 6 is urged against the rotary disk 1 by said piston and a reaction ~5 generated thereby i.A

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urges the other pad 6 a~ainst khe rotary disk 2.
Each pad 6 comprises two kinds of linings 8, 9 and 9 secured to one surface o~ a back plate 7 which is disposed on the caliper bod~ 5. That is, in such pads 6 and 6 for a disk brake, an uneven wear is liable to occur on one side portion of each rotary disk 1, 2 in the circumferential direction thereof (the right end side or left end side in FIG. 2).
When this uneven wear occurs, a less-worn portion on the disk, that is, its other end side portion in the circumferential direction encounters a lar~er drag than the one side portion during non-braking ~o allow gene~ation of a.
local wear on the rotar~ disk 1, 2, which may lead to an abnormal vibration or sound generation during braking.
In view of this, on one surface of the back plate 7 there are provided an area lOa at a central portion thereof and areas lOb and lOc on opposite sides thereof. The area lOa at the central portion is secured with a lining 8 formed of a material capable of assuring a sufficient braking force when it is pressed against the rotary disk 1, 2, and the areas lOb and lOc on the opposite sides are secured with linings 9 and 9, respectively, which are formed of a material having such a propert~ that makes the rotar~
disk hard to bring forth a local wear thereon when a drag occurs.
The linings 8, 9 and 9 are formed b~ molding the .~ , ; . :
. ~:

~3~39~9 granules in preC~siny and heating conditlons. As the granules used, there can be mentioned a compositlon com-prising, for example, fibers, lubricants, polishing mate~ial, filling material and binding material, and specific examples thereof are mentioned below. Numerals in parentheses indicate the compound quantity (weight %).
Fibers: Steel, asbestos, etc. (20 to 40~) Lubricants: Black lead, molybdenum disulfide, baryte, calcium carbonate, etc. (15 to 20~) Polishing material: Oxides and non-oxides (1 to 5%) Oxides: A12O3r SiO2~ Cr2O3~ Fe23' Fe34' ZrO2, MgO, CaO, etc.
Non-oxides: SiC, BN, BC, Si3N4, AlN, etc.
Filling material: BaSO4, CaCO3, etc.
Binding material: Phenol resin (which is often used as denatured resin to which is added melamine, nylon, epoxy, oil, cresol, etc.) or the like.
(6 to 12%).
In addition to the above, vulcanized or unvulcani~ed natural rubber or synthetic rubber, cashew grains obtained by pulverizing cashew resin (5 to 10%). These are mainly used as a material for regulating the frictional coefficient and also have a function for improvi~g the damping character-istics of pads to prevent occurrence of noises.
Moreover, the lining B corresponding to the central J, :

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13~3979 area lOa is molded with a greater content of polishing material than that of the linings 9 and 9 corresponding to the areas lOb and lOc on the opposite sides.
The method for manufacturing the pads 6 for the disk brake will now be described with reference to FIGS. 3(a) to 3(e). In the manufacture of the pad 6, a molding frame 11 is first prepared as shown in FIG. 3(a). This molding frame 11 has a cross-sectional shape corresponding to the entire shape of the linings 8, 9 and 9 shown in FIG. 2, and the bottom of the molding frame 11 held in an upright state is closed by a detachable bottom plate 12. The m~ld- ¦
ing frame 11 has an interior partitioned previously b~ parti-tioning plates 13 and 14 in order to define the areas lOa to lOc to be set by the back plate 7, and respective required quantities of yranules 15, 16 and 16 for molding of the corresponding linings 8, g and 9 are charged into the portions in the frame 11 corresponding to the areas lOa to lOc.
Subse~uently, as shown in ~IG. 3(b), the partitioning plates 13 and 14 are removed. In this step, before or after removing the partitioning plates 13 and 14, the upper sur-face of the granular layer accumulated on the bottom plate 12 is levelled by means of a brush or the like.
Thereafter, as shown in FIG. 3~c), the granular layer on the bottom plate 12 is pressed relatively lightl~ from ' ~, .. , ~ ~ ~ . . ; . , .
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the top to achieve a preli.minary moldin~ as linings 8', 9' and 9'. Upon termination of this preliminary molding step, the bottom plate 12 is removed from the moldin~ frame 11.
The thus preliminarily molded linings 8', 9' and 9' are placed on a heat molding die 17 while keeping their state housed in the molding frame 11 as shown in FIG. 3(d).
This molding die 17 comprises an upper die half 19 having a through-hole 1.8 formed therethrough which can be flush with and continuous to the inner surface of the molding frame 11 and a lower die half 20 which is detachably co~pled to the upper die half 19. The back plate 7 is placed on an upper surface of the lower die half 20 so as to be flush with said upper surface and close the lower end opening of the molding frame 11, the back plate 7 having its peripheral edge held between the upper die half 19 and the lower die half 20. In this state, into the interior of the molding frame 11 is relativel~ powerfully pressed down a press means or the like from the top thereof whereb~
molding of the linings 8, 9 and 9 is completed on the back plate 7.
Next, as shown in FIG. 3(e), the molding frame 11 is removed, and the linings 8, 9 and 9 are pressed from the top thereof while being subjected to heating, whereby the linings 8, 9 and 9 are secured to one surface of the back plate 7 at the predetermined areas lOa to lOc. Thus the _ g _ . ~
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pad 6 is obtained by molding. Then, the pad 6 may be removed from the heat molding die 17.
During this molding process of the linings R, 9 ahd 9, the granules present at boundary portions be~ween the areas lOa and lOb and between the areas lOa and lOc are pLessed from the top in a state placed in contact with each other after the partitioning plates 13 and 14 have been removed, as shown in FIG. 3(b). Therefore, the granules of different compositions are mixed together at the positions between the areas lOa and lOb and between the areas lOa and lOc.
Accordingly, the joining force obtained between the linings 8, 9 and 9 after molding becomes lar~e, and the strength of the linings 8, 9 and 9 between the areas lOa to lOc will not be weakened.
Furthermore, molding of the linings 8, 9 and 9 and securing of these linings 8, 9 and 9 to the back plate 7 are carried out in a series of steps, and therefore the manufacturing process can be simplified.
Next, one embodiment of a disk brake to which is attached a modified form of a pad for a disk brake manufactured by the aforementioned method of the present invention will be described with reference to FIGS. 4 to 7.
Prior to the description of this embodiment of the disk brake, an outline of one conventional disk brake will be described with reference to FIG. 12 for the purpose of : -.

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comparison. A conventional disk brake Br ` is provided with a pair of pads 104' and 105' each having a linlng 112' which is entirely formed o~ one and the same material and is secured to one surface of a back plate 111'. As a material ~or the lining 112' there is normally used a relatively hard material capable of obtaining a sufficient frictional force when the lining comes into frictional contact with a rotary disk 101'. Accordingly, when an uneven or one-sided wear occurs in the lining 112' at one end thereof in the rotational direction of the rotary disk 101' d~e to the caliper rigidit~ or the like, a less-worn port~on 112'a on the lining 112' comes into one-sided contact with the rotar~ disk 101' during non-braking as shown in FIG. 12 to cause the rotary disk 101' to be partl~ worn out. Such a partial wear of the rotary disk 101' results in abnormal vibration or sound occurrence during braking operation.
The embodiment of the disk brake shown in FIGS. 4 to 7 overcomes the problems involved in the aforementioned conventional disk brake by mounting a modified pad which i i5 manufactured by the method according to the present invention.
The construction of this disk brake will be described hereinafter with reference to FIGS. 4 and 5. A disk brake Brl is operable to apply a braking force to a wheel of a vehicle and it comprises a bracket 102 mounted on a vehicle ~ .

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~323979 body (not shown) so as to straddle over a rotary disk 101 mounted on the wheel, a caliper 103 s~ppor-ted on the bracket 102 in`a manner movahle in a limited range in a direction parallel with the axis of the rotary disk 101, and a pair of pads/ that isr an inner pad 104 and an outer pad 105 which are respectively arranged between opposite sides o~ the rotary disk 101 and the caliper 103 for frictional contact with the opposite sides of the rotar~ disk 101.
The bracket 102 is provided with a bracket body 102a having a pair of mounting holes 106 adapted to be mo~nted on the body-through bolts not shown and arranged on one side.of the rotary disk 101, and a pair of supporting arms 102b and 102b each being formed into an approximately U-shape and extended Erom the upper portion of the bracket bod~ 102 so as to straddle over the rotary disk 101 at positions spaced from each other in the rotational direction of the rotary disk 101.
The caliper 103 comprises a caliper body 103a arranged on one side of the rotary disk 101, a pair of arms 103b and 103b extended from the upper portion of the caliper body 103 toward the other side of the rotar~ disk 101 at positions spaced from each other in the rotational direction .
of the rotary disk 101, a connecting portion 103c connect-ing both the arms 103b and 103b on the other side of the ~ - 12 -,,, - .;

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rotar~ disk 101, and a pa.ir o~ caliper pawls 103d and 103d suspended downwardly from opposite ends o the connecting portion 103c. To the callper body 103a are secured a pair of slidable pins 107 and 107 which are slidably fitted into the supportin~ arm5 102b and 102b of the bracket 102 in a direction parallel with the axis of the rotary disk 101.
Thus, the caliper 103 is supported on the bracket 102 b~
means ~f the slidable pins 107 and 107 such that the caliper 103 may be slidably moved in the direction along the axis of the rotary disk 101.
The cali.per body 103a of the caliper 103 ls formed with a c~linder bore 108 extending parallel with the axis of the rotar~ disk 101 and having its side remote from the rotary disk 101 being closed. A piston 110 is slidably fitted into the cylinder bore 108 to define an oil pressure chamber 109 against the closed end of the latter. The piston 110 is formed into a bottomed cylindrical shape and is slidably fitted into the cylinder bore 108 with the closed end thereof facing the oil pressure chamber 109.
Referring also to FIG. 6, each of the inner pad 104 and the outer pad 105 is formed with a lining 112 which is secured to one surface of a back plate 111. The inner pad 104 is arranged between the caliper body 103a and the rotary disk 101 in such a manner that an open end of the piston 110 is placed in contact wi-th the back of the back .
.

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plate 111, whereas the outer pad 105 is arranged between the rotar~ disk 101 and the caliper pawl5 103d and 103d such tha~ the pair of caliper pawls 103d and 103d o~ the caliper 103 are palced in contact w.ith the back of the back plate 111. Shoulders llla and llla are provided on opposite ends of each back plate 111 and are respectively supported on guide steps 113 and 113 provided on the supporting arms 102b and 102b of the bracket 102.
The lining 112 comprises, unlike the one in the preceding embodiment of FIGS. 1 to 3, a first lining por-tion 112a located at one end in ~he rotational direction of the rotary disk 101 and a second lining portion 112b which occupies the remaining principal portion (FIG. 6).
The second lining portion 112b is formed of a material capable of obtaini.ng a sufficient frictional force when the lining comes into frictional contact with the rotary disk 101, for example, a material having a composition as given in Table A below.
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-_ .
Composition Weight %
_ Fibers (a) Aramide fiber 3 - 6 _ .
. (b) Steel fiber lO - 15 Lubricant (c ) Graphite (MoS2) 5 - lO
(e) Antimony trisulfide (SbS3) Metal powder (f) Copper (Cu) .
_ (g) Zinc (Zn) 20 - 40 (h) Brass (CuZn) _ Polishin~
material (i) Silica (SiO2) (j) Zirconia (ZrO2) l - 5 (k) Alumina (Al203) . _ Filler (l) Baryte (BaS04) (m) Calcium carbonate 20 - 30 . (CaC03 ) (n) Cashew dust _ _ _ . material (o) Phenol resin 10 - lZ
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1323~79 1l The first lining portion 112a is formed of a material which is hard to damage the rotary disk 101 as compared with the second llning portion 112b, and for example, it is formed of a ~aterial having the composition of the above Table but excluding (b) steel fiber from its fibers and the polishlng material~ that is, (i) silica, (j) zirconia and (k) alumina. Both the pads 104 and lOS are manufactured by the aforementioned method o~ the present invention, and the joining force between the first and second lining portions 112a and 112b is kept at a high level.
Referring also to FIG. 7, the lihing 112 is formed to have a thickness d thereof reduced grad~ally from one to the other side along the rotational direction 114 of the rotary disk 101, and a difference ~ between the maximum thickness and the minimum thickness is set, for example, to 0.1 to 0.5 mm. The first lining portion 112a is arranged at the end where the thickness d is maximum, and the inner pad 104 and outer pad 105 are each arranged to have the first lining portion 112a positioned on the side thereof on which the possibilit~ of causing a one-sided contact with the rotary disk 101 becomes maximum during non-braking. That is, the bracket 102 is cantilever-supported on a vehicle body on the side of the inner pad 104, and the caliper 103 is cantilever-supported on the bracket 102 on the side of the inner pad 104. Therefore, ., .

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during braking, a turning moment as indicated by arrow 115in FIG. 7 acts t~ cause that end side (right end side) of the inner pad 104 at which frictional contact with the rotary disk 101 begins to be more strongl~ pressed against the rotary disk 101 and also to cause that end side (left end side) o~ the outer pad 105 at which frictional contact with the rotary disk 101 terminates to be more strongly pressed against the rotary disk 101. Because of this, the lining 112 of the inner pad 104 tends to wear unevenly at its frictional contact beginning end side with respect to the rotary disk 101, whereas the lining 112 of the outer pad 105 tends to wear unevenl~ at its frictional contact terminating end side with respect to the rotary disk 101.
Accordingly, during non-braking, the lining 112 of the inner pad 104 comes into one-sided contact with the rotary disk 101 at the terminating end side of frictional contact with the rotary disk 101, whereas the lining 112 of the outer pad 105 comes into one-sided contact with the rotary disk 101 at the beginning end side of frictional contact with the rotary disk 101. In the present embodiment, the inner pad 104 is arranged with the first lining portion 112a positioned on the end side thereof at which frictional contact with the rotar~ disk 101 terminates, whereas the outer pad 105 is arranged with the first lining portion 112a positioned on the end side thereof at which frictional i ~, !

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~32~79 contact with the rotary disk 101 begins.
Next, the operation of the disk brake B~1 provided with the aforementioned s~r~cture will be described. At the time of braking, pressure oil is suppl.ied to the oil pressure chamber 109 whereby the piston 110 is urged left-ward in FIG. 4 so that the inner pad 104 is pressed against the rotary disk 101, and the caliper 103 itself is moved by the reaction thereof to push the outer pad 105 by the caliper pawls 103d and 103d toward the rotar~ disk 101.
Thus the braking force is obtained b~ the frict`ion between .
both the linings 112, 112 and the rotary disk 101.
The thickness d of the lining 112 is made uneven in the rotational direction 114 of the rotary disk 101, and therefore, during non-braking, that portion o the lining 112 at which the thickness d is maximum comes into one-sided .
contact ~ith the rotary disk 101. Moreover, since the first lining portion 112a formed of a material which is hard to damage the rotary disk 101 is arranged at the portion where sald one-sided contact occurs, that is, the end where the thickness d is maximum, wear of the rotary disk 101 to be caused by such one-sided contact is suppressed, and the occurrence of abnormal vibration or sound can be avoided.
Furthermore, since the first lining portion 112a formed of a material which is hard to damage the rotary disk 101 is provided only on one end portion o each rotary disk 101 . ~. ' ~.

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in the rotational direction 114, a sufficient frictional force can be obtained by the remaining principal portion, that is, the second lining portion 112b durlng braking.
Even i the first lining portion 112a formed of a material which is hard to damage the rotary disk 101 is provided on the lining 112, the frictional force during braking is not significantly ].owered.
As a modified form of this embodiment of the disk brake Brl, the second lining portion 112b in the lining 112 may be formed of the material having the composition shown in the above-described Table Ar and the first lining portion 112a may be formed of a material having a composi-tion different from the Table composition in the content of lubricant, that is, with the amount of (c) graphite, (d) molybdenum disulfide and (e) antimony trisulfide being increased by 1.5 to 2.5 times, for example, so as to prevent the one-sided wear of the rotary disk 1.
Next, another modified example of a pad for a disk brake manufactured by the aforementioned method of the present invention will be described with reference to FIGS.
8 and 9.
FIG. 8 shows an inner pad 204 of a pair of pads, the inner pad 204 being formed by securing a linin~ 215 to one surface of a back plate 214. The lining 215 comprises a first lining portion 215a at a central portion in the ' 1 ~, , .. 19 :.

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rotational directior, oE the rotary disk 101, and a second and a third lininy portion 215b and 215c on opposite ends in the rotational direction of the rotary disk 101. The first lining portion 215a is formed of the same material as that of the second lining portion 112b of the embodiment shown in FIGS. 4 to 7 so as to obtain a suficient frictional force during its frictional contact with the rotary disk 101. The second and third lining portions 215b and 215c are formed of the same material as that of the first lining portion 112a of the embodiment shown in FI~S. 4 to 7, which is hard to damage the rotar~ disk 101 as compared with the first lining portion 215a. In FIG. 8, portions indicated at 214a and 214b are shoulders by which the inner pad 204 is supported on the guide steps of the bracket, such as ones 113, 113 shown in FIG. 5. The inner pad 209 is manufactured by the aforementioned method of the present invention, and the joining force between the lining portions 215a, 215b and 215c can be large.
On the other hand, as shown in FIG. 9, the outer pad 205 is formed by securing a lininq 212 to one surface of a back plate 211, the lining 212 being formed of the same material as that of the first lining portion 215a, that is, a material that ma~ obtain a sufficient frictional force .
at the time of frictional contact with the rotary disk 101.
In FIG. 9, portions indicated at 211a and 211a are shoalders , .

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~3~3~7~

by which the outer pad 205 is supported on the guide steps of the bracket, such as ones 113, 113 shown in FIG. 5. This outer pad 205 is manufactur~d by a conventional manufactur-ing method.
Next, the operation of this embodiment will be described. During non-braking of the disk brake, a drag is liabl~ to occur at opposite ends of the respective linings 212 and 215 in the rotational direction of an associated rotary disk, and when an amount of wear in the rotar~ disk increases due to occurrence o the drag, an abnormal vibration or sound occurs. In view of this, when the opposite ends of each of the linings 212 and 215 in the rotational direction of the rotary disk are formed of a material which is hard to damage the rotary disk, ~he wear caused in the ro~ary disk by the drag is suppressed, and occurrence of an abnormal vibration or sound can be avoided. However r the outer pad Z05 is pushed by a pair of spaced caliper pawls such as ones indicated at 103d in FIG. 4, and therefore, the level of surface pressure at the time of braking is nearly equalized over the entire surface of the lining 212. Because of this, when the opposite ends of the lining 212 is formed of a material which is hard to damage the rotary disk, the frictional force obtainable at these opposite ends is liable to become small at the time of braking. On the other hand, in case ,, ,ji " .

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of the inner pad 204, a piston comes into contact with the .
back plate 214 at a central portion of the latter ih the rotational direction of the rotary disk, and therefo~e, the level o surface pressure at the opposite ends of the llning 215 becomes low. Owing to this, even if the opposite ends of the lining 215r that is,. the second and third lining portions 215b and 215c are formed of a material which is hard to damage the rotary disk, the frictional force obtain-able at the time o braking operation is not significantly lowered. . .
Because of this, in the present modified form, the lining 212 of the outer pad 205 is formed at its whole surface of one and the same material to avoid lowering in the frictional force, and the second and third lining por-tions 215b and 215c on the opposite ends o the inner pad 204 are formed of a material which is hard to damage the rotary disk to prevent to the utmost the occurrence of abnormal vibration or sound to be caused by a drag while avoiding lowering in the frictional force, the~eb~ ensuring a sufficient braking force as a whole.. Moreover, since the lining 212 of the outer pad 205 is simpl~ formed of one ~ and the same material in its entirety, a cost reduction can I -- be attained.
~ In this modified form,. the first lining portion 215a ~, i .~ of the inner pad 204 and the lining 212 of the outer pad 205 ~. ;
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' ~323~7~

may be ormed of the material having the composition shown in the above-descrlbed Table A, and the second and third linin~ portions 215b and 215c of the inner pad 204 may be formed of a mater~al of the Table composition but with the amount of lubricant, that is, (c) graphitet (d) molybdenum disulfide and (e) antimony trisulfide being increased b~
1.5 to 2.5 times, for exampler thus making the rotary disk hard to be damaged.
Since, as has been previously mentioned, the lining 215 of the inner pad 204 comes only at one end thereof in the rotational direction of the rotar~ disk into contact with the disk during non-braking, it ma~ be sufficient that only the said one end is formed of a material which is hard to damage the rotary disk.
Still another modified form of a pad for a disk brake manufactured by the aforementioned method of the present invention will be described with reference to FIGS. 10 and 11.
A pair of pads, that is, an inner pad 304 and an outer pad 305, according to this modified form, have the same construction. As shown in FIGS. 10 and 11, a lining 312 is secured to one surface of a back plate 3110 This lining 312 comprises first lining portions 312a and 312a on opposite ends in the rotational direction of the rotar~ disk and a second lining portion 312b occupied in the remaining portion including a central portion in the said rotational direction.

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- : , ~323979 The first lining portion 31~a is formed of the same material as that of the first lining portion 112a in the embodiment of FIGS. 4 to 7 which is hard to damage a rotar~ disk as compared w~th the second lining portion 312b. The second lining portion 312b is formed o the same material as that of the second llning portion 112b in the embodiment of FIGS.
4 to 7. In the present modified example, on the s~rface of the second lining portion 312b is provided a polishing material layer 314 having such a thickness, for example, of 0.2 to 0.5 mm that will allow the layer to be f~lly worn out due to its repeated frictional contact with the rotary disk several times, for example, 5 to 20 times. This polishing material la~er 314 is formed of a polishing material used in the embodiment shown in FIGS. 4 to 7, for example. Portions indicated at 311a and 311a in FIG. 10 are shoulders by which the inner and outer pads 304 and 305 are supported on the guide steps of the bracket, such as ones 113, 113 shown in FIG. 5. Both the pads 304 and 305 are manufactured b~ the aforementioned method of the present invention, and the joining force between the first and second lining portions 312a and 312b becomes large.
The operation of this modified form will be described hereinafter.
At an initial stage of use after the inner pad 304 and the outer pad 305 have been mo~nted on a disk braket ,, . .
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the surace o~ the rotary disk is polished by the polishin~
material layer 314 throu~h several times of braking opera~
tions. Accordingly, even if the rotar~ disk has a rugged-ness on its surEace, the surface can be smoothed and made flat. Since the polishing material layer 314 is provided on the surface of the second linin~ portion 312b which occupies the central portion of the lining 312, the s~rface pressure is concentrated thereon during the braking opera-tion so that the polishing material la~er 314 is worn out relatively early and then the surface of the second lining portion 312b appears. Since the second lining portion 312b is arranged outside the area which comes into one-sided contact with the rotary disk during non-braking, the polishing material layer 314 will not frictionally contact with the rotary disk during non-braking.
At the time of non-braking after the rotary disk 314 has been polished, the inner pad 304 and the outer pad 305 are liable to induce a drag at one end in the rotational direction of the rotary disk as has alread~ been described.
However, the first lining portions 312a and 312a at the opposite ends of the lining 312 along the Lotational direc-tion of a rotary disk are formed of a material which is hard to damage the rotary disk, and therefore, even if the first lining portions 312a and 312a come into one-sided contact with the rotary disk during non-braking~ the wear ,, ... .

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~323~79 of the rotary disk 101 can be suppressed. Moreover, since the surface of the rotary disk is smoothed by the polish-ing material laye~ 314 a~ the initial stage of use as mentioned above, it is possible to positivel~ prevent one-sided wear of the rotary disk and prevent occurrence of abnormal vibration or sound during braking.
Also in this modified form, the second lining portion 312b of the lining 312 is formed o~ the material having the composition shown in the above-described Table A, and the first lining portion 312a is formed of a material corresponding in composition to that of Table A but having the lubricant~ that is, (c~ graphite, (d) mo~ybdenum disulfide and (e) antimon~ trisulfide increased in quantity by 1.5 to 2.5 times, for example. Thereby the rotar~ disk can have a property hard to be damaged.
Furthermore, since the lining 312 has a tendenc~ to be brought at only one end thereof in the rotational direc-tion of the rotary disk into one-sided contact with the rotary disk during non-braking, it is sufficient to provide the first lining portion 312a only at one end of the lining 312 and the second lining portion 312b at the remaining portion including the central portion and the other end.
In this manner, the lowering in the frictional force caused by the first lining portion 312a can be minimized.

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Claims

1. Method for manufacturing a brake body for a disk brake, said body having a flat back plate and a lining on said back plate as friction lining, with at least two lining portions having different friction characteristics, the method comprising the following steps:

charging certain amounts of granulated materials, allocated to the different lining portions, into a moulding frame having a partitioning device separating the different lining portions from one another;

simultaneously moulding all lining portions on said back plate by pressure treatment; and conducting heat treatment, under pressure, of all lining portions on said back plate.

2. Method according to claim 1, wherein said molding consists of a pre-molding step and a main-molding step.

3. Method according to claim 1, wherein said pre-molding step and said main-molding step are executed in a molding frame.

4. Method according to claim 1, 2 or 3, wherein as the granulated materials for the lining, one containing the following components is used:

fibres, lubricants, oxides, non-oxides, loading agents, bonding materials.

5. Method according to claim 4, wherein as the granulated material one additionally containing caoutchouc or cashew-flour is used.

6. Method according to claim 1, 2 or 3, wherein as the granulated material for the lining, one containing the following components is used:

fibres, lubricants, metal powder, abrasives, loading agents, bonding materials.

7. Method according to any one of claims 1 to 3 or 5, wherein for at least one lining portion, forming the main part of the lining surface of the lining, such granulated material is used, that said lining portion secures a sufficient braking force and that for at least one other lining portion, forming an edge portion of the lining surface, such granulated material is used, that said other portion hardly damages the brake disk.

8. Method according to claim 7, wherein the amount of abrasives, contained in the granules for the other lining portion, is reduced as compared to the granulated lining material for said one lining portion.

9. Method according to claim 7, wherein the share of lubricants in the granulated material for said other lining portion is more than the share of lubricants in said granulated material for said one lining portion.