JP2002295557A - Manufacturing method of friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a lining thickness without decreasing porosity and damping performance, besides prevent occurrence of lining crack caused by insufficient gas venting. SOLUTION: This method includes a process to mix a compounding process to manufacture the mixed ingredient 14, a process to mold the mixed ingredient 14 by cold compression molding in a die together with a backing metal 11 and a process to pinch the mixed material 14 and the backing metal which is molded by compression with a pair of a plates 27, 28 heated in high temperature and mold by compression again to the specified thickness so that an orthogonal direction to the overlapping direction can be released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a brake friction material mainly used for a vehicle brake device.

[0002]

2. Description of the Related Art A method of manufacturing a brake friction material is disclosed in Japanese Patent Application Laid-Open No. 6-159407. This manufacturing method includes a step of integrally forming a mixed material produced by mixing the lining compounding materials into a backing metal having holes or recesses at a cold time to produce a preform, and the preform is formed by a side frame. By pressing with a higher pressure by the surrounding die and heating from the side frame and the pressing die, the thermosetting resin contained in the lining compound material was reacted and cured to form a shape, and was applied to the back metal Adhering the lining to the backing metal with an adhesive.

[0003]

However, the above conventional manufacturing method has the following problems. (1) As described above, since the heat-compression molding is performed using the mold surrounded by the omnidirectional frame composed of the side frame and the pressing mold, the outer peripheral portion close to the mold is sufficiently cured by the thermosetting resin, but the central portion of the lining is formed. There is a portion where the thermosetting resin is not sufficiently cured, and as a result, the thickness of the central portion becomes thicker than the thickness of both sides. In order to make the thickness constant, when heating is performed with a long heating time to sufficiently cure the thermosetting resin in the central portion, the lining of the outer peripheral portion becomes dense, the porosity is reduced, and sufficient Fade characteristics cannot be obtained, and brake squeal often occurs due to poor damping. (2) Since the thermosetting resin is heat-cured in a mold surrounding the entire periphery, a curing reaction gas is generated, and at the same time, moisture absorbed evaporates to generate steam. In order to eliminate these curing reaction gases and water vapor, a pressure release step called degassing to open the pressing mold is required.However, since the temperature and humidity of the external environment change variously depending on the season and weather, mixing The temperature of the material, the amount of moisture absorption, the temperature of the backing metal, the temperature distribution in the mold, and the like are not constant, and depending on the external environment, poor gas release may occur and the lining may be cracked. (3) As described above, the outer peripheral portion of the lining becomes dense,
That is, since the outer peripheral portion has a higher hardness than the inner peripheral portion of the lining, brake squealing occurs, but in order to prevent this, it is necessary to chamfer the outer peripheral portion, and the production of the brake friction material becomes complicated. Has become.

The present invention has been made in view of the above circumstances, and it is possible to make the thickness of a lining constant without lowering the porosity and damping property, and to generate cracks in the lining due to poor gas release. It is an object of the present invention to provide a method and an apparatus for manufacturing a brake friction material which can prevent the occurrence of the frictional force and can be easily manufactured.

[0005]

In order to achieve the above object, a method for producing a brake friction material according to the present invention comprises the steps of: mixing a lining compounding material to produce a mixed material; Compressing the mixed material and the back metal in a cold direction together with the back metal in a direction in which the direction perpendicular to the overlapping direction is opened from both outer sides in the overlapping direction. And further compression molding to a predetermined thickness by sandwiching between hot plates.

As described above, the mixed material is cold-formed together with the back metal in the mold, and the compression-formed mixed material and the back metal are formed from both outer sides in the overlapping direction in a direction perpendicular to the overlapping direction. Is compression-molded to a predetermined thickness by sandwiching it with a high-temperature hot plate so as to open. For this reason,
Since the mixture and the back metal are heated by the hot plate only from both sides in the overlapping direction, the mixture is heated on average. Further, since the mixture and the back metal are open in the direction orthogonal to the overlapping direction, the gas can always be sufficiently vented.

The apparatus for producing a brake friction material according to the present invention comprises the steps of mixing a lining compounding material to produce a mixed material, and compressing the mixed material together with a back metal in a mold while cold. An intermediate molded product comprising the mixed material and the back metal formed through the above is further subjected to heat compression molding, and the intermediate molded product is formed from both outer sides in the overlapping direction of the mixed material and the back metal constituting the intermediate molded product, It is characterized by having a pair of high-temperature hot plates for sandwiching and compressing the direction orthogonal to the overlapping direction in an open state, and a gap defining means for defining a gap between the pair of hot plates.

Thus, an intermediate molded product obtained by cold-pressing the mixed material together with the back metal in the mold is opened from both outer sides in the overlapping direction of the mixed material and the back metal in a direction perpendicular to the overlapping direction. As described above, a pair of high-temperature hot plates are compressed to a predetermined thickness by a compression to a distance specified by a distance specifying means. For this reason, since the mixture and the back metal are heated by the heating plate only from both sides in the overlapping direction, the mixture is heated on average. Further, since the mixture and the back metal are open in the direction orthogonal to the overlapping direction, the gas can always be sufficiently vented.

In this case, by using a spacer which is interposed between the pair of hot plates to define the interval between the hot plates as the interval defining means, the interval between the pair of hot plates can be easily and reliably defined. can do.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

The brake friction material 1 manufactured in this embodiment
0 is a back metal 11 made of a metal plate as shown in FIG.
And a lining 12 that is joined to one side of the back metal 11 in the thickness direction (vertical direction in FIG. 1) and is joined to the back metal 11 in the same thickness direction.

The present embodiment has an adhesive application step of applying an adhesive for bonding the lining 12 after the back metal 11 is sufficiently cleaned.

Further, the present embodiment has a mixed material manufacturing step of manufacturing the mixed material 14 by mixing the compounding materials of the lining 12. The compounding material of the lining 12 is, for example, copper fiber, aramid fiber, a phenol resin which is a thermosetting resin as a binder, graphite as a lubricant, molybdenum disulfide, etc., cashew dust as a friction modifier,
Rubber powder, metal oxide powder, mineral pulverized powder, barium sulfate as a filler, and calcium hydroxide as a pH adjuster are mixed and mixed in a predetermined amount to produce a mixed material 14.

In this embodiment, the mixed material 14 is used.
Compression molded together with the backing metal 11 in the cold
5 has an intermediate molding step.

FIG. 2 shows an intermediate molded product manufacturing apparatus 17 used in the intermediate molding step. In the intermediate molded product manufacturing apparatus 17, the back metal 11 to which the adhesive has been applied in the adhesive applying step is placed with the adhesive side facing upward, and the hole 18 disposed above the back metal 11 is provided. It has a mold 21 composed of a female mold 19 formed and a male mold 20 fitted into the hole 18 of the female mold 19 from above. The surface 22 forms an outer peripheral surface 23 in a direction perpendicular to the thickness direction of the mixed material 14 manufactured in the mixed material manufacturing process and metered into the hole 18, and the tip end surface 24 of the male mold 20 is formed on the back metal of the mixed material 14. A tip surface 25 opposite to 11 is formed.

In the intermediate molding step, the back metal 11 is placed on the female mold 19 of the above-mentioned intermediate molded product manufacturing apparatus 17, and the hole 18 of the female mold 19 is placed above the back metal 11. A predetermined amount of the mixed material 14 manufactured in the mixed material manufacturing process is charged, and the male mold 20 is moved in the direction of the back metal 11 to be compressed as shown in FIG.

Here, the female type 19 and the male type 20 are
Since there is no heating means for heating these, compression is performed at normal temperature, that is, cold without heating. For this reason, although the shape of the mixed material 14 is maintained by being compacted by pressure, the phenol resin which is a thermosetting resin as a binder is not cured, and the mixed material 1 is not cured.
4 is not completely hardened. The compression pressure in the intermediate molding step is, for example, 150 MPa.
And high pressure.

In the present embodiment, the intermediate molded product 15 molded in the intermediate molding step is opened from both outer sides in the overlapping direction of the mixed material 14 and the back metal 11 in a direction perpendicular to the overlapping direction. A pair of hot plates 2
There is a heating and compression step of further compressing and molding to a predetermined thickness by sandwiching between 7, 28.

FIG. 3 shows an apparatus 30 for producing a brake friction material used in the heating and compression step. In the brake friction material manufacturing apparatus 30, a hot platen 27 on which the intermediate molded product 15 formed in the intermediate forming step is placed with the back metal 11 facing down, and a hot platen 27 are mounted on the hot platen 27. The top surface of the intermediate molded product 15, that is, the front end surface 2 opposite to the back metal 11 of the mixed material 14.
And a hot platen 28 arranged so as to face the intermediate molded product 15 while the pair of hot plates 27 and 28 approach each other while maintaining a state of being parallel to each other.
Is compressed so that it is sandwiched from both sides.

Here, the lower heating plate 27 has a flat surface on which the mounting surface 31 on which the back metal 11 is mounted extends further outward than the entire circumference in a direction perpendicular to the thickness direction of the back metal 11. In addition, the upper heating plate 28 also has a flat surface in which the contact surface 32 abutting on the distal end surface 25 of the mixture 14 extends further outward than the entire circumference in the direction orthogonal to the thickness direction of the mixture 14. Has become. With these, a pair of hot plates 2
The entire peripheral direction in the direction between 7, 28 and the direction orthogonal to the thickness direction of the intermediate molded product 15 is opened.

The pair of hot plates 27 and 28 are heated to a temperature higher than the normal temperature by heating means (not shown), respectively.
Specifically, it is heated to 160 ° C.

Further, the brake friction material manufacturing apparatus 30 includes:
When the intermediate molded product 15 is compressed from both sides by the pair of hot plates 27, 28, a spacer (space defining means) which is sandwiched between the pair of hot plates 27, 28 to define the interval between the hot plates 27, 28 ) 33. The spacer 33 corresponds to the thickness of the brake friction material 10 after the intermediate molded product 15 is heated and compressed.
5 is lower than the thickness.

In the heating and compression step, as shown in FIG. 3, the intermediate molded product 15 molded in the intermediate molding step is placed on the hot platen 27 below the above-mentioned brake friction material producing apparatus 30 with the back metal 11 placed downward. Side. Then, from this state, the upper heating plate 28 is moved toward the lower heating plate 27 while maintaining a state parallel to the lower heating plate 27. Then
The upper hot platen 28 comes into full contact with the front end face 25 of the mixed material 14 of the intermediate molded product 15, descends while compressing the mixed material 14, comes into contact with the spacer 33 and stops. Then, this state is maintained for a predetermined time, specifically, 5 minutes. Then 1
Heat is transmitted from the lower hot platen 27 heated to 60 ° C. to the mixed material 14 via the back metal 11 from the entire lower surface, and
The heat is transmitted from the upper hot platen 28 heated to 0 ° C. to the mixed material 14 from the entire upper surface, and the phenol resin which is a thermosetting resin as a binder is hardened, and the mixed material 14 is completely hardened. As shown in FIG.

Then, the brake friction material 10 after the heating and compression process is further heat-treated at a higher temperature, specifically 220 ° C., for a predetermined time, specifically 6 hours.
2 is subjected to groove processing and surface polishing.

According to the embodiment described above, the mixed material 1
An intermediate molded product 15 obtained by cold-pressing the mold 4 together with the back metal 11 in the mold 21 is opened from both outer sides in the overlapping direction of the mixed material 14 and the back metal 11 in a direction orthogonal to the overlapping direction. Hot platen 27, 28
Then, it is compressed to an interval defined by the spacer 33 and formed into a predetermined thickness. Therefore, the mixture 14 and the back metal 1
1 is a hot platen 27, 28 only from both sides in the overlapping direction.
Therefore, the mixed material 14 is heated on average, the lining 12 after heating is not dense, the porosity can be secured to 15 to 20%, and the thickness of the lining 12 is kept constant. be able to. Further, at the time of heating and compression, the mixture material 14 and the back metal 11 are opened in the direction orthogonal to the overlapping direction, so that the gas can always be sufficiently ventilated without performing the gas venting operation.

Therefore, the thickness of the lining 12 can be made constant without lowering the porosity and the damping property, and the lining 12 caused by poor gas venting.
Cracks can be prevented.

Further, since the spacer 33 sandwiched between the pair of hot plates 27, 28 is used to define the interval between the pair of hot plates 27, 28, the pair of hot plates 27, 28 can be easily and reliably connected. 28 can be defined. In addition, even if the heating compression molding step is performed for a sufficiently long time, the interval between the pair of hot plates 27 and 28 can be favorably maintained during that time.

Further, by manufacturing in the above process,
The brake friction material 10 can make the hardness of the outer peripheral edge portion in the direction orthogonal to the thickness direction lower than the hardness of the central portion on the tip surface 25 side opposite to the back metal 11 of the lining 12, so that the The brake friction material 10 with reduced squeal noise can be obtained. Therefore, there is no need to chamfer the outer peripheral edge of the lining to prevent squeal noise, and the manufacture of the brake friction material 10 is facilitated.

Here, for the embodiment of the brake friction material manufactured as described above, the thickness, hardness, defect occurrence rate,
Shear strength, friction characteristics (JASO C
-406), and an abnormal noise confirmation test was conducted using an actual vehicle.

For comparison, only the mixed material was cold-compressed at room temperature at a pressure of 30 MPa using a predetermined mold to form a preform, and the preform and the backing metal coated with the adhesive were formed. Into a mold heated to 150 ° C.,
After performing heat compression molding at a pressure of Pa for 250 to 300 s, a heat treatment was further performed at 220 ° C. for 6 hours, a lining was subjected to groove processing and surface polishing was prepared as a comparative example, and the same test was performed.

The results are shown in Table 1.

[0032]

[Table 1]

As is clear from Table 1, when looking at the thickness of the lining, the lining of the embodiment has a uniform pressure at the end and the center in the direction orthogonal to the thickness direction. It can be seen that this is superior to the comparative example in which the thickness differs between the end and the center.

Looking at the hardness of the lining, in the lining of the embodiment, the hardness at the end in the direction orthogonal to the thickness direction is lower than the hardness at the center.
This is different from the comparative example in which the hardness at the end in the direction perpendicular to the thickness direction is higher than the hardness at the center. As described above, since the hardness of the end of the lining is lower than the hardness of the center, high-frequency squeal such as squeal noise caused by frictional vibration of the pad end can be prevented. That is,
As a result of an actual vehicle confirmation test, it can be seen that the brake friction material of the example has a squeal noise occurrence rate of 0, which is superior to the comparative example in which the occurrence rate is 2.6%.

Further, when looking at the defect occurrence rate such as cracking and swelling, the lining of the embodiment has a defect occurrence rate of 0%.
It can be seen that this is superior to the comparative example in which the defect occurrence rate is 2.1%.

Looking at the shear strength, it can be seen that the lining of the example secures the same shear strength as the comparative example.

In addition, it can be seen that the friction characteristics of the brake friction material of the example are almost equal to those of the comparative example.

[0038]

As described above in detail, according to the method for producing a brake friction material of the present invention, the mixed material is cold-formed together with the backing metal in the mold, and the compression-formed mixed material and The back metal is sandwiched between high-temperature hot plates from both outer sides in the overlapping direction and opened in a direction perpendicular to the overlapping direction, and is further compression-molded to a predetermined thickness. For this reason, since the mixture and the back metal are heated by the hot plate only from both sides in the overlapping direction, the mixture is heated on average. Further, since the mixture and the back metal are open in the direction orthogonal to the overlapping direction, the gas can always be sufficiently vented.

Therefore, the thickness of the lining can be made constant without lowering the porosity and damping property, and the occurrence of cracks in the lining due to poor gas release can be prevented. In addition, the brake friction material can reduce the hardness of the outer peripheral edge in the direction orthogonal to the thickness direction at the tip end surface side of the lining to be lower than the hardness of the central portion, thereby reducing the squeal noise during braking. Can be obtained. Therefore, it is not necessary to chamfer the outer peripheral edge of the lining in order to prevent squeal noise, thereby facilitating the manufacture of the brake friction material.

According to the brake friction material manufacturing apparatus of the present invention, an intermediate molded product obtained by cold-compression-molding the mixed material together with the back metal in the mold is obtained from both outer sides in the overlapping direction of the mixed material and the back metal. Then, it is compressed to a predetermined thickness by a pair of high-temperature hot plates so as to open in a direction orthogonal to the overlapping direction to a distance specified by a distance specifying means. For this reason, since the mixture and the back metal are heated by the heating plate only from both sides in the overlapping direction, the mixture is heated on average. Further, since the mixture and the back metal are open in the direction orthogonal to the overlapping direction, the gas can always be sufficiently vented.

Therefore, the thickness of the lining can be made constant without lowering the porosity and damping property, and the occurrence of cracks in the lining due to poor gas release can be prevented. In addition, the brake friction material can reduce the hardness of the outer peripheral edge in the direction orthogonal to the thickness direction at the tip end surface side of the lining to be lower than the hardness of the central portion, thereby reducing the squeal noise during braking. Can be obtained. Therefore, it is not necessary to chamfer the outer peripheral edge of the lining in order to prevent squeal noise, thereby facilitating the manufacture of the brake friction material.

In this case, by using a spacer which is interposed between a pair of hot plates to define the interval between the hot plates, it is possible to easily and surely define the interval between the pair of hot plates. Can be.

[Brief description of the drawings]

FIG. 1 is a side view showing a brake friction material manufactured according to an embodiment of the present invention.

FIG. 2 is a side sectional view showing an intermediate molded product manufacturing apparatus used in one embodiment of the present invention.

FIG. 3 is a side view showing a state before the heating and compression of the brake friction material manufacturing apparatus according to the embodiment of the present invention.

FIG. 4 is a side view showing a state at the time of heating and compression of the brake friction material manufacturing apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Brake friction material 11 Back metal 12 Lining 14 Mixing material 15 Intermediate molded product 27, 28 Hot platen 30 Brake friction material manufacturing device 33 Spacer (space defining means)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J058 AA62 BA21 BA46 GA07 GA12 GA20 GA22 GA28 GA31 GA37 GA38 GA45 GA55 GA61 GA88 GA92 4F204 AD03 AG03 AH17 FA01 FA18 FB01 FB11 FF01 FF05 FN15

Claims (3)

[Claims] 1. A step of mixing a lining compounding material to produce a mixed material; a step of cold-pressing the mixed material together with a back metal in a mold; A step of further compressing the back metal to a predetermined thickness by sandwiching the back metal between a pair of high-temperature hot plates so that a direction perpendicular to the overlapping direction is opened from both outer sides in the overlapping direction. A method for producing a brake friction material, comprising: 2. The method according to claim 1, further comprising the steps of: mixing a lining compounding material to produce a mixed material; and cold-compressing the mixed material together with a back metal in a mold. An apparatus for manufacturing a brake friction material, which further heat-press-molds an intermediate molded product comprising a back metal, wherein the intermediate molded product is formed from both outer sides in the overlapping direction of the mixed material and the back metal constituting the intermediate molded product, in the overlapping direction. An apparatus for manufacturing a brake friction material, comprising: a pair of high-temperature hot plates for sandwiching and compressing a direction orthogonal to an open state and a space defining means for defining a space between the pair of hot plates. 3. The brake friction material manufacturing apparatus according to claim 2, wherein said interval defining means is a spacer which is sandwiched between said pair of hot plates to define an interval between said hot plates. .