JP2002003280A - Sliding member of carbon-fiber-reinforced carbon and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sliding member of carbon-fiber-reinforced carbon whose carbon fibers are placed homogeneously in circumferential direction and in diameter direction and its efficient manufacturing method. SOLUTION: This is the sliding member 1 which comprises at least a disc part 2 of carbon-fiber-reinforced carbon having a sliding surface 2a and an axial core 3 connected to the disc and is the sliding member who characteristically comprises helical fabric 4 in which diameter direction threads 5 of carbon fiber and/or circumferential direction threads 6 of carbon fiber are used for the disc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a sliding member for a brake or a clutch made of carbon fiber reinforced carbon material used for a drive system of a transportation device such as an automobile or a motorcycle and a method of manufacturing the same. .

[0002]

2. Description of the Related Art Hitherto, as is well known, members made of carbon fiber reinforced carbon, which is a material having both heat resistance and slidability, have been used for brakes and clutches of transportation equipment such as automobiles. I have. In manufacturing these sliding members made of carbon fiber reinforced carbon (hereinafter simply referred to as sliding members), a flat or three-dimensional base material (also referred to as a preform) made of carbon fibers is impregnated with a binder at a temperature of several thousand degrees centigrade. The firing is repeatedly performed at a high temperature, and the obtained product is subjected to appropriate external processing.

[0003] In the sliding member for the above use, its performance,
The substrate greatly affects the productivity, but the method for producing the substrate is roughly classified into a woven fabric in which carbon fibers are arranged in a two-dimensional direction and a three-dimensional fabric in which carbon fibers are arranged in a three-dimensional direction. It is known to use textiles.

[0004] The finished sliding member usually has a thickness of several mm to several tens of mm, and is often in the form of a donut-shaped disk, and some are combined with a metal material. When used as a material, lamination is repeated a plurality of times in the thickness direction to obtain a required thickness. When a three-dimensional fabric is used as a base material, the fibers are arranged in a shape close to the final shape (for example, a donut shape), immersed in a binder, fired (carbonized / graphitized), and then molded. .

Since a force acts on the sliding member not only in the plane but also in the thickness direction, a three-dimensional woven fabric in which carbon fibers can be manually arranged in any direction is suitable. Also,
In the case of a two-dimensional woven fabric, a method of stitching in the thickness direction after lamination may be adopted.

[0006]

However, a typical structure of a two-dimensional woven fabric using carbon fibers is a structure called plain weave or satin weave, and a sliding member using this woven fabric is made of carbon fiber. Since the array is orthogonal to the vertical and horizontal directions in the two-dimensional plane, the sliding characteristics of the rotating sliding member are not uniform with the rotation. There is a problem that the directions are not uniform. For this reason, there has been a problem that the friction coefficient and the wear amount are different between the circumferential direction and the radial direction.

Further, when the finished sliding member has a curve such as a donut shape or an arc, it is necessary to cut the woven fabric into the shape. There is an economic problem that a large amount of loss occurs, and there is an environmental problem associated with disposal and incineration. Further, in manufacturing, since thin fabrics are stacked, there is a problem that the thicker the sliding member is, the more labor is required.

On the other hand, when the base material is a three-dimensional woven fabric, the carbon fibers can be manually arranged in any direction, but a large amount of productivity required for industrial use has not been obtained. Further, there is a problem that the fibers generate steric hindrance to each other and generate heat at a matrix-rich portion, thereby causing cracks and uneven dimensional changes. for that reason,
The sliding properties may be inferior to those of a two-dimensional fabric. Furthermore, the number of times of binder impregnation and firing must be increased by the amount of the fiber content lower than that of the two-dimensional woven fabric, so that there is a problem that much labor, time and cost are required. In any case, the biggest problem is that the dimensional change accompanying heat generation is non-uniform in the circumferential and radial directions.

An object of the present invention is to solve the problems that occur when the above-described two-dimensional fabric or three-dimensional fabric is used as a base material, and have uniform sliding characteristics over the entire sliding surface. An object of the present invention is to provide a sliding member and a method of manufacturing a sliding member with high productivity.

[0010]

In order to achieve the above object, a sliding member according to the present invention has the following features. That is, at least, a sliding member including a disk portion made of carbon fiber reinforced carbon material having a sliding surface, and a shaft connected to the disk portion, wherein the disk portion is formed of a warp or a carbon fiber. And / or a helical woven fabric serving as a weft.

In the method for manufacturing a sliding member according to the present invention, a plurality of carbon fibers are arranged in parallel as warps, and the carbon fibers are interlaced as wefts in a direction substantially orthogonal to the warp by a weft insertion device. By rotating the putting device at a predetermined radius, the obtained fabric is successively stacked in a spiral shape in a plurality of layers, and after manufacturing a spiral fabric having a predetermined thickness as a whole, impregnated with a binder, and then carbonized. This is a method of manufacturing a sliding member made of carbon fiber reinforced carbon.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of an example of the sliding member of the present invention, FIG. 2 is a view of a spiral fabric constituting the sliding member, and FIG. 3 is a plan view of a disk portion of the sliding member.

In FIG. 1, a sliding member 1 of the present invention comprises a disk-shaped disk portion 2 and a shaft center 3, and both members are integrated by appropriate means. The disk portion 2 has a sliding surface 2a on its surface. The sliding surface comes into contact with another member such as a clutch plate or a brake disk, and the driving force transmitted from the shaft center 3 by appropriate driving means. Slidably. The shaft center 3 is directly connected to the disk portion 2 in the present embodiment. However, even if the shaft center 3 is connected to a driving means or a member such as an appropriate joint in the middle between the two members, the sliding member of the present invention is constituted. I do. The material of the shaft core 2 may be any material, but a metal member having sufficient rigidity and strength, an aluminum carbon fiber reinforced plastic, or the like is preferable.

The disk part 2 is a donut-shaped spiral woven fabric 4
Is impregnated with a matrix resin and baked as a whole. Here, the spiral woven fabric 4 will be described with reference to the schematic diagram of FIG. First, when a plurality of carbon fibers are arranged in parallel and a warp 5 constituting the entire width W is supplied in the direction of the arrow in the figure, one weft 6 is supplied into the weft insertion device 7 from a direction perpendicular to the direction. . The weft insertion device 7 has a detailed mechanism omitted, but the weft 6
Can be interwoven with a plurality of warps 5 at an arbitrary weaving structure, and can be rotated about a center line C at an arbitrary rotation radius R by a device (not shown). Therefore, the woven fabric sequentially manufactured with the full width W has an outer diameter of 2R +
W spiral fabric. In the spiral woven fabric 4 obtained by such a manufacturing method, since the warp is not continuously cut in the circumferential direction and is arranged in a concentric spirally stacked manner, the warp and the weft used for the sliding member as a finished product include: There will be no waste. Further, since the spiral woven fabric has a spiral shape, it naturally overlaps in the thickness direction to form a thick donut-shaped disk, and an object having an arbitrary thickness can be obtained by adjusting the rotation speed of the weft insertion device.

Here, as the thread used for the spiral woven fabric, for example, carbon fiber or glass fiber is preferable, but carbon fiber is preferable in terms of strength and rigidity. As carbon fiber,
Any of PAN-based, pitch-based, and rayon-based carbon fibers may be used. When a carbon fiber is used, the elastic modulus of the elastic fiber is a high elasticity yarn having a graphitized structure for improving slidability, an elastic modulus of 350 GPa or more, or a crystal size (Lc) of 70 or more, more preferably 80 or more. Those are preferred because they reduce the amount of wear during sliding. The crystal size is calculated from a diffraction peak obtained by irradiating a carbon fiber sample having a width of about 1 mm with X-rays and obtaining a transmission method. Further, the filament diameter of the carbon fiber is in a range of 3 to 15 μm which can be deformed to a small curvature in order to reduce the yarn breakage due to the bending deformation of the yarn in the manufacturing process of the spiral woven fabric and the manufacturing process of the base material of the sliding member. Are preferred. Furthermore, when the density of the weft of the spiral woven fabric is increased,
It is necessary that the weft bend at a smaller curvature in the above-described weft insertion device. However, when the weft is in the range of 3 to 10 μm, a very high-density structure can be obtained without fiber breakage. The higher the fiber density, the lower the coefficient of thermal expansion and the smaller the dimensional change during heat generation, that is, not only the temperature dependence of the sliding characteristics can be reduced, but also the heat transfer coefficient improves,
There is also an effect that the temperature rise can be reduced.

Although the basis weight of the spiral woven fabric 4 depends on the final thickness of the sliding member, it is preferably in the range of 1 to 5 mm for the sliding member for automobiles, and is preferably in the range of 100 to 800 g / m2. If the amount is less than 100 g / m2, productivity may not be improved, and if the amount is more than 800 g / m2, thickness control becomes difficult.

The higher the amount of carbon fiber in the sliding member volume, the better. However, considering the balance between productivity and sliding characteristics, the volume content Vf is 40 to 85%.
% Is preferable. If it is less than 40%, the productivity is low,
If it exceeds 85%, it becomes difficult to impregnate the binder as the matrix resin. A more preferred range is 60 to 80%.

As the binder to be impregnated in the sliding member, for example, phenolic resin, furan resin, benzoixazine resin, coal pitch, petroleum pitch and the like, and a mixture thereof can be used. preferable.

Although the outer dimensions of the disk portion 2 are determined by the use of the sliding member, the ratio (D / D) between the inner diameter (d) and the outer diameter (D) of the spiral woven fabric 4 is required to exhibit the characteristics of the spiral woven fabric 4.
d) is preferably in the range of 1.2 <D / d <10. Below 1.2, the sliding member is close to a ring and is not practical. On the other hand, if it is 10 or more, the radial density of the weft becomes denser between the inside and the outside of the donut, and a difference in sliding characteristics between the inside and the outside can occur. More preferably, it is in the range of 1.2 <D / d <3. Even if the ratio (D / d) of the inner diameter to the outer diameter is 1.2 or less, as shown in FIG. 4, if two or more types of spiral woven fabrics 4a and 4b having different outer shapes are concentrically arranged, the sliding is performed. A donut-shaped sliding member having a large moving area can be produced. Also,
The reinforcing fibers may be arranged in the thickness direction of the spiral woven fabric. Specifically, a three-dimensional woven sliding member can be made by laminating a plurality of spiral woven fabrics in a donut shape and then sewing the same in the thickness direction with a stitch thread made of carbon fiber or organic fiber. This has the effect of improving the strength in the thickness direction.

The sliding member 1 of the present invention configured as described above has the following effects. That is, as shown in the plan view of the disk portion 2 in FIG.
Inside, the warp yarn 5 and the weft yarn 6 made of carbon fiber are arranged almost uniformly along the circumferential direction (X) and the radial direction (Y), so that the impregnation of the binder into the spiral woven fabric is smooth (flow (Small resistance), and the resulting sliding member 1 is of high quality without voids or cracks after firing caused by insufficient or excessive binder portions. Therefore, when the sliding member is used for an automobile clutch, the sliding characteristics in the circumferential direction and the radial direction of the disk portion are always constant, and the unevenness of the sliding characteristics of the clutch when a shift is changed in an automobile or the like. Knocking, vibration and noise caused by the above are reduced. In addition, vibration and noise due to the non-uniformity of the brake disc during braking are reduced, and braking is uniform and very smooth. Furthermore, since the sliding member made of the base material is arranged uniformly in two directions, that is, the circumferential direction and the radial direction, the fibers are unevenly worn at a specific location due to friction due to rotation, or worn at a specific position. No noise is generated, and the wear and generated noise are uniform.

The sliding member is heated to a high temperature by frictional heat generated by sliding rotation. However, since the linear expansion coefficient is substantially uniform in the radial direction and the circumferential direction, thermal cracks are less likely to occur. Furthermore, when a two-dimensional woven fabric such as a plain woven fabric is used as the woven structure of the spiral woven fabric 4, there is no unevenness of deformation due to the generated heat, no subsequent peeling or cracking, and the sliding characteristics are stable and highly reliable. This also prevents damage due to thermal fatigue and improves durability.

Next, a method of manufacturing the sliding member will be described in the order of steps. A. Spiral woven fabric manufacturing process First, from the sliding characteristics and outer dimensions (outer diameter D, inner diameter d, thickness T) required for the use of the sliding member 1 of the present invention, the thickness, number, and number of the carbon fibers 5 and 6 to be used are determined. The manufacturing conditions (rotation radius R, number of rotations) of the spiral woven fabric 4 are designed, and the spiral woven fabric 4 is manufactured using the manufacturing apparatus described with reference to FIG. B. Binder impregnation step Next, the spiral woven fabric 4 is impregnated with a resin. The spiral woven fabric may be impregnated with resin at any part of the production line, but it is efficient to provide a resin impregnation bath immediately after the weft insertion device 7 in FIG. Further, a roller for removing excess resin is provided to adjust the amount of resin adhering to the spiral fabric so that the spiral fabric is impregnated with the resin amount calculated from Vf of the sliding member to be manufactured. C. After the carbonization step A and the step B, the spiral woven fabric is impregnated with resin and piled up in a disk shape.
Carbonized under the condition of ° C. In addition, as a carbonization method, 600-
A normal pressure carbonization method in which a binder is repeatedly filled at 3000 ° C. several times, an HP (hot press) method in which a base material and a binder are filled into a carbon die of a hot press furnace, and then heat and carbonized while being uniaxially pressed from above and below, A PIC (pressure impregnation & carbon method) method in which impregnation and carbonization are performed simultaneously can be applied. D. Forming process Step Sliding member disk 2 made of spiral woven fabric obtained through the above steps
After polishing the sliding surface 2a of the
Attach. The attachment method of the shaft center and the disk portion may be anything such as mechanical joining or bonding. Although the disk portion 2 has a roughly donut shape as shown in the figure, the final shape of the sliding member does not necessarily have to be a donut shape. Depending on the application, the donut-shaped disk portion may be machined and cut into a fan shape as shown in FIG. In addition, it is also preferable to perform unevenness processing on the inner circle side for joining.
Further, it may be combined with another metal material or ceramic material in a hybrid manner.

The production method of the present invention comprising the above steps
Since the spiral woven fabric 4 is used as the sliding member, the arrangement density of the carbon fibers is uniform and extremely high in productivity, which is incomparable with a three-dimensional woven fabric or the like in which carbon fibers are manually assembled. The sliding member 1 having a thick disk portion can be easily manufactured. Furthermore, since the step of cutting the fibers and the substrate, which is indispensable in the production of the two-dimensional fabric and the three-dimensional fabric, is almost unnecessary, the loss of the substrate is very small, and the production method is resource saving and environmentally friendly. Another feature is that even if a product having a thickness several times that is required during manufacture, a product having an arbitrary thickness can be obtained only by changing the setting of the number of turns of the spiral.

[0025]

EXAMPLES (Example) Elastic modulus 500 GPa, crystal size 8
2. Using a pitch-based carbon fiber having a diameter of 10 μm,
mm, spiral woven fabric with an outer diameter of 200 mm (with a basis weight of 200 g / m2,
After winding 15 turns of the warp and the weft in a quantity ratio of 1: 1 and Vf of 50%), a carbonization treatment at 1000 ° C. and a graphitization treatment at 2800 ° C. are repeated three times by a normal pressure method using a phenol resin as a binder. A 3 mm thick sliding member made of carbon fiber reinforced carbon material was obtained. When the coefficient of linear thermal expansion of this sliding member was measured, it was within 1% variation over the entire circumference. Further, the variation in the friction coefficient in the circumferential direction was within 3%. For this reason, no thermal cracks due to non-uniformity of frictional heat due to rotation were observed, and there was no abnormal noise or vibration due to variations in friction in the circumferential direction.

Incidentally, the loss of carbon fibers in the present production process was zero. (Comparative Example) Elastic modulus 235 GPa, crystal size 50, diameter 7μ
m PAN-based carbon fiber plain weave cloth (with a basis weight of 2
00g / m2, the number ratio of the warp to the weft is 1: 1) in a donut shape (inner diameter 50 mm, outer diameter 200 mm, Vf is 50%)
After 15 sheets were cut out and superimposed on each other, a carbonization treatment at 1000 ° C. and a graphitization treatment at 2800 ° C. were repeated three times by a normal pressure method using a phenolic resin as a binder, to obtain a thickness of 3
mm sliding member made of carbon fiber reinforced carbon material was obtained. When the linear thermal expansion coefficient of this member was measured, there was a variation of 3% over the entire circumference. The variation in the circumferential friction coefficient was 5%. For this reason, thermal cracks occurred due to variations in the coefficient of linear expansion, and the durability of the product was significantly reduced. In addition, abnormal noise and vibration were generated due to variations in the coefficient of friction.

The loss of the carbon fiber fabric in the production process was 26%. In addition, carbon fibers fell off from the end of the woven fabric cut out during the operation, and handling was difficult.

[0028]

In the sliding member of the present invention, since the spiral woven fabric is used for the disk portion, which is a constituent member thereof, the arrangement of the carbon fibers is uniform in the circumferential direction and the radial direction of the disk portion. Therefore, the occurrence of thermal cracks due to the non-uniformity of the coefficient of linear expansion when the sliding member is used is suppressed, and the durability is significantly improved. Further, since the friction coefficient is constant in the circumferential direction due to the uniform arrangement of the carbon fibers, generation of abnormal noise and vibration during rotation of the disk portion can be suppressed. Further, according to the production method of the present invention, since the spiral woven fabric is used as the sliding member material, carbon fibers can be produced with high productivity without loss.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sliding member of the present invention.

FIG. 2 is a schematic view illustrating a method for producing a spiral woven fabric in a sliding member according to the present invention.

FIG. 3 is a plan view of a disk portion of the sliding member of the present invention.

FIG. 4 is a plan view of the sliding member of the present invention in a mode different from that of FIG. 1;

FIG. 5 is a perspective view showing an example of a working mode of the sliding member of the present invention.

[Explanation of symbols]

 1: Sliding member 2: Disc portion 2a: Sliding surface 3: Shaft center 4: Spiral fabric 5: Warp 6: Weft 7: Weft insertion device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J056 AA58 AA62 BA02 BE09 BE17 CA04 CA15 EA02 EA14 EA30 GA02 GA12 3J058 BA55 BA61 FA01 GA27 GA55 GA61 GA73 GA82 GA92 GA93 4G032 AA14 AA52 BA03 GA09

Claims (12)

[Claims] 1. A sliding member comprising at least a disk portion made of carbon fiber reinforced carbon material having a sliding surface and a shaft connected to the disk portion, wherein the disk portion is made of carbon fiber. Characterized in that the sliding member is constituted by a spiral woven fabric having a warp and / or a weft. 2. The spiral woven fabric according to claim 1, wherein (a) a plurality of continuous warp yarns are arranged concentrically in a circumferential direction with a void portion in the center in a donut shape, and the weft yarn is the warp yarn. A fabric that intersects in a direction substantially orthogonal to
The sliding according to claim 1, wherein (b) the woven fabric of (a) is laminated concentrically in a plurality of layers, and (c) the warp of the woven fabric of each layer is spirally continuous. Element. 3. The ratio (D / d) between the inner diameter (d) and the outer diameter (D) of the spiral woven fabric is within a range of 1.2 <D / d <10. Sliding member. 4. The carbon fiber has a crystal size of 3 to 20 n.
4. The sliding member according to claim 1, wherein the distance is within the range of m. 5. A carbon fiber having a filament diameter of 3 to 15 μm.
The sliding member according to any one of claims 1 to 4, wherein 6. The spiral fabric has a basis weight of 100 to 800 g / fiber.
The sliding member according to any one of claims 1 to 5, wherein the sliding member is within a range of m2. 7. The sliding member according to claim 1, wherein the volume content of carbon fibers in the sliding member is in the range of 55 to 80%. 8. The sliding member according to claim 1, comprising at least a phenol resin as a binder. 9. The sliding member according to claim 1, wherein the sliding member is an automobile member. 10. The sliding member according to claim 1, wherein the thickness of the sliding member is in the range of 1 to 5 mm. 11. The sliding member according to claim 1, wherein the sliding member is a part of a donut-shaped disk. 12. A method in which a plurality of carbon fibers are arranged in parallel as warps, while the carbon fibers are interlaced as wefts in a direction substantially orthogonal to the warp by a weft insertion device, and the weft insertion device is rotated at a predetermined radius. By successively stacking a plurality of layers of the obtained woven fabric sequentially in a spiral shape, after manufacturing a spiral woven fabric having a predetermined thickness as a whole, by impregnating the binder, and then carbonized, the carbon fiber reinforced carbon A method for manufacturing a sliding member for manufacturing a sliding member.