KR20200016237A - Carbon / carbon composite spring device and its manufacturing method - Google Patents

Abstract

(Problem) Provided is a spring element that can be used repeatedly in a high temperature environment over 1000 ° C., and has a high torsional rigidity that can support a large load, and can be used as a spring washer.
(Solving means) A spring element having a helical toroidal shape, wherein the spring element is a helical toroidal spring element having a configuration composed of a two-dimensional carbon / carbon composite material having a layer structure laminated in the axial center direction of the spring element. .

Description

Carbon / carbon composite spring device and manufacturing method thereof

The present invention relates to a spring element made of a carbon / carbon composite material, which can be exhibited in particular by use in a high temperature environment. More specifically, it relates to a spring element that can be used as a spring washer in a high temperature environment and a method of manufacturing the same.

Spring elements, which can be used as spring washers, are used in various machines, devices, and apparatuses as mechanical elements, and are now essential parts essential for household goods, industrial goods, and other fields.

Conventionally, spring washers are generally made of a metal material, and stainless steel, low alloy steel, tool steel, titanium alloy, and the like are mainly used. However, the spring washer of the metal material is poor in heat resistance and does not exhibit sufficient spring characteristics in a high temperature use environment. Thus, in high temperature environments, spring washers of metallic materials are not available or prolonged use in high temperature environments.

For example, even in a spring washer made of a heat resistant alloy, in a high temperature environment over 400 ° C., the strength reduction and deformation of the spring washer are remarkable, and the settling resistance of the spring washer also decreases drastically. Accordingly, even spring washers made of heat resistant alloys cannot be used as spring washers in such high temperature environments.

When spring washers are used in a high temperature environment above 400 ° C., spring washers made of super heat-resistant alloys such as Inconel alloys and Hastelloy alloys may be used. However, even spring washers made of super heat-resistant alloys cannot be used as springs in such high temperature environments, since the strength decreases and deformations are remarkable in high temperature environments exceeding 700 ° C, and the support resistance of the spring washers is drastically reduced.

In addition, spring washers can be manufactured using ceramics such as silicon nitride and zirconia in place of Inconel alloy, Hastelloy alloy, and the like. However, since ceramic spring washers are inherently low in toughness and susceptible to thermal shock, they are likely to break if used repeatedly in high temperature environments. In addition, in a high temperature environment of more than 500 ~ 1000 ℃, a sudden drop in strength of the ceramic spring washer may occur and may be broken.

In order to solve the above problem, a spring washer made of a carbon / carbon composite material (also called a “C / C composite material”) is disclosed (see Patent Document 1).

Carbon / carbon composites (“C / C composites”) are fiber reinforced composites formed by hardening carbon fibers, which are reinforcing fibers, into a graphite or carbon matrix. Carbon / carbon composites have several times more strength and modulus than conventional carbon or graphite materials, and have excellent heat resistance, abrasion resistance and toughness, leading to the nose cap and wing of space shuttles. Edge; Brakes on aircraft, racing cars, shinkansen vehicles and heavy duty trucks; Internal structures, trays, and heaters in heat treatment furnaces; Forks for product handling used in furnaces for manufacturing semiconductors and solar cells; And various parts such as high temperature jig for metal processing.

The spring washer made of the carbon / carbon composite material disclosed in Patent Document 1 is manufactured by the following production method.

(1) A prepreg woven into a carbon fiber bundle or sleeve shape having a tensile strength of 200 kg / mm ² (1.96 Gpa) or more and a tensile modulus of 24000 kg / mm ² (235.2 Gpa) or more formed on the outer surface of the cylindrical jig Wound in a spiral groove, semi-hardened by a heating process,

(2) Next, the semi-coiled shaped body is removed from the cylindrical jig, and further heated to fully cure to obtain a coiled shaped body,

(3) Next, the coil-shaped molded body is carbonized by additional heating, and if necessary, the coil-shaped molded body is impregnated at a melt pitch, and graphite-treated by heat treatment to form a carbon-carbon composite having a coil-shaped molded body. The material is created,

(4) Furthermore, a spring washer made of CCM (carbon / carbon composite material) is completed by cutting and separating the coil shaped molded body in a single turn.

As the spring washer made of the carbon / carbon composite material disclosed in Patent Literature 1 is manufactured by the manufacturing method as described above, carbon fibers, which are long fibers, extend along the wires of the coils or the wires of the coils. Along the spiral. Accordingly, the carbon / carbon composite spring washer has a strength and elastic modulus that can be used as a spring washer. However, carbon / carbon composite spring washers have low torsional stiffness as spring washers that support large loads (spring washers are important for high torsional stiffness). Accordingly, the carbon / carbon composite spring washer disclosed in Patent Document 1 cannot exhibit sufficient capacity.

In addition, since the spring washer made of the carbon / carbon composite material disclosed in Patent Document 1 employs the above-described manufacturing method, a different jig having a spiral groove is required for each spring washer having a different diameter. In addition, the spring washer is cut and separated in a single turn from the coil-shaped molding, which makes it difficult to mass-produce a spring washer made of carbon / carbon composite material and has a higher manufacturing cost.

Japanese Patent Laid-Open No. 9-079248

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical background, and is a spring element that can be repeatedly used even in a high temperature environment over 1000 ° C. An object of the present invention is to provide a spring element.

In order to solve the said subject, in the invention which concerns on a 1st viewpoint, it includes the spring element which has a spirally annular shape, and this spring element is parallel to the surface of the said spring element toward the center axis direction of a spring element. It is characterized by being made of a two-dimensional carbon / carbon composite material having a laminated layer configuration.

In addition, in the invention according to the second aspect, the invention includes a spring element having a spirally annular shape of the invention according to the first aspect, wherein the two-dimensional carbon / carbon composite material is a carbon fiber nonwoven fabric facing the direction of the central axis of the spring element. It has a layer structure laminated | stacked parallel to the surface of the said spring element.

Moreover, in the invention which concerns on a 3rd viewpoint, as a manufacturing method of the spring element which has a spirally annular shape,

Form a plate of carbon / carbon composite material or a preform plate of carbon / carbon composite material having a layer structure formed by laminating a sheet unidirectionally oriented carbon fiber, a carbon fiber woven fabric, or a carbon fiber nonwoven fabric. Steps,

Cutting out the annular shaped body having a central angle of less than 360 degrees from the plate of carbon / carbon composite material or the preliminary plate of carbon / carbon composite material,

Spirally shaping the annular shaped body, and

A helical toroidal spring element manufacturing method comprising the steps of heat-treating a shaped body having a helical toroidal shape.

Moreover, in invention which concerns on 4th viewpoint, in the manufacturing method of the spring element which has a spirally annular shape of invention of 3rd viewpoint, the range of heat processing temperature is the spirally annular spring of the structure which is 1000 degreeC-3000 degreeC. It is set as a device manufacturing method.

Further, in the invention according to the fifth aspect, in the method of manufacturing a spring element having a spirally annular shape of the invention according to the third or fourth aspect, in the heat treatment step of the element having the spirally annular shape, the spring element A heat treatment of the device having a spirally annular shape is performed while maintaining the shape of.

In the present invention, it is possible to provide a spring element which can be repeatedly used even in a high temperature environment of more than 1000 ° C. by being a spring element made of a carbon / carbon composite material having the technical characteristics as described above.

Further, in the spring element having a spirally annular shape having a layer structure in which a carbon fiber nonwoven fabric is laminated in parallel with the surface of the spring element facing the center axis direction of the spring element, the torsional rigidity of the spring element can be remarkably improved. . As a result, it is possible to provide a spring element having a high torsional rigidity capable of supporting a large load.

In addition, by using the spring element manufacturing method of the spirally annular shape which concerns on this invention, since it does not need to use the expensive jig for manufacturing a spring element, and is easy to cut, mass production and manufacturing cost of a spring element are easy. Can be reduced.

Figure 1 shows a representative example of a spring device made of a carbon / carbon composite material according to the present invention.
Figure 2 shows a typical manufacturing process of the spring device made of a carbon / carbon composite material according to the present invention.

Hereinafter, a spring device manufactured from the carbon / carbon composite material according to the present invention will be described.

Carbon / carbon composites (also called C / C composites) are fiber reinforced composites formed by hardening carbon fibers, which are reinforcing fibers, into a graphite or carbon matrix. Compared with conventional carbon or graphite materials, carbon / carbon composite materials have several times more strength and modulus, and have excellent heat resistance, wear resistance, and toughness. Carbon / carbon composites are also known as materials having high specific strength and high specific stiffness due to their low specific gravity and high strength and stiffness (elastic modulus).

Conventionally, carbon / carbon composite materials have been produced in which carbon fibers are arranged in various directions, wherein carbon fibers are arranged only in one direction, carbon fibers are arranged in two or multiple directions in plan, and carbon fibers are three-dimensionally In addition to arranging in three directions, arranging carbon fibers (short fibers) randomly in two or three dimensions, arranging carbon fibers in various patterns has been devised until now.

In addition to the method of producing carbon / carbon composite materials, in addition to the resin-char method, the CVD method, the method of using preformed yarns, and the like, short fiber carbon fiber, binder pitch powder and coke powder A method of using a sheet-shaped intermediate material (prepreg-shaped sheet) composed of a super binder has been developed.

1 shows a representative example of a spring element 1 made of a carbon / carbon composite material according to the present invention. The spring element 1 comprises a main body portion 11 having a helical annular shape, one end side 12 of the main body portion 11 and the other end side 13 of the main body portion 11, wherein the helical annular shape As shown in FIG. 1, the main body portion 11 is defined as a state extending helically from the one end side 12 to the other end side 13. Further, the circumferential angle from the one end side 12 of the spring element 1 to the other end side 13 is smaller than 360 degrees, and the slit 14 between the one end side 12 and the other end side 13 of the spring element 1. ).

The cross-sectional dimensions (w, b), the outer diameter (D) and the height (H) of the main body portion 11 of the spring element 1 (refer to FIG. 1 for each dimension) act on the spring element 1. It is determined according to the load condition and the amount of warpage of the spring element 1. In addition, although the shape of the cross section of the main-body part 11 of the spring element 1 is shown in rectangular shape in FIG. 1, the cross-sectional shape of the main-body part 11 is not limited to a rectangle.

The spring element 1 according to the present invention is composed of a carbon / carbon composite material in which two-dimensional (carbon fibers as reinforced fibers are arranged in two dimensions), and the spring element 1 facing the central axis direction of the spring element 1. It has a layer structure laminated parallel to the plane of).

Here, "the layer structure laminated | stacked in parallel with the surface of the spring element 1 toward the center axis direction of the spring element 1" means the center axis direction (X of FIG. 1) of the spring element 1 shown in FIG. Layer) is formed by stacking parallel to the "a1" plane (top side in the front view of FIG. 1) and the "a2" plane (bottom surface in the front view of FIG.

In each layer of the two-dimensional carbon / carbon composite material according to the present invention, various kinds of carbon fibers can be used. For example, an angle-ply-laminated sheet formed by laminating carbon fiber sheets oriented in one direction while changing the orientation direction, a woven fabric using carbon fiber bundles, and short fiber carbon fibers Nonwovens or the like oriented in a random manner such as paper may be used for the layer.

Next, an embodiment of the manufacturing method of the spring element 1 made of the carbon / carbon composite material according to the present invention will be described.

The manufacturing method described here is a manufacturing method using a carbon fiber nonwoven fabric. That is, the said manufacturing method uses the sheet-shaped intermediate material (prepreg-shaped sheet) which consists of short fiber carbon fiber, binder pitch powder, coke powder, and a caking additive. However, the manufacturing method of the spring element 1 made of the carbon / carbon composite material of the present invention is not limited thereto.

The sheet-shaped intermediate material (prepreg-shaped sheet) used in the manufacturing method of the spring element 1 made of the carbon / carbon composite material used in the present embodiment includes short-fiber carbon fibers, binder pitch powder, coke powder and It consists of a binder.

In this embodiment, polyacrylonitrile (PAN) type carbon fiber, rayon type carbon fiber, or pitch type carbon fiber can be used as carbon fiber. In addition, any type of carbon fiber that has been heat treated, carbonized or graphite for fire resistance may be used. In this embodiment, carbon fiber is a short fiber, 1-50 mm long carbon fiber is preferable, and 1-25 mm carbon fiber is more preferable.

In addition, the binder beach powder used in this embodiment is extracted from petroleum and / or coal having softness, has a softening temperature in the range of 60 to 320 ° C, and is 0 to 80 weight of a quinoline insoluble substance. % And binder pitch powder having isotropic, potentially anisotropic or anisotropic obtained from petroleum and / or petroleum having a volatile content of 10 to 60% by weight.

This binder pitch powder is used for bonding the reinforcement fiber (carbon fiber) and the coke powder which functions as aggregate mentioned later. The average particle diameter of the binder pitch powder is preferably 0.5 to 60 microns, and more preferably 3 to 20 microns.

In addition, the coke powder used in this embodiment is petroleum and / or coal type coke powder which does not have softening property, functions as aggregate, and does not have a softening point. In addition, the volatile matter of the coke is preferably less than 10% by weight, more preferably less than 2% by weight.

In this embodiment, coke powder can use either petroleum or coal type | system | group, The average particle diameter of coke powder should be 0.5-30 microns, and it is still more preferable if the average particle diameter is 1-20 microns.

The blending ratio of petroleum and / or coal-based binder pitch powder having softness and petroleum and / or coal-based coke powder having no softening is not limited to a specific value, but the blending weight ratio of [binder pitch powder] / [coke powder] 90/10 ~ 10/90 is good, 70/30 ~ 30/70 is better.

In addition, a binder used in the present embodiment is used to bind the binder pitch powder and the coke powder and at the same time bind the mixture composed of carbon fiber and binder pitch powder, coke powder and the binder. As a caking additive, what is industrially used as a thickening stabilizer (or paste), such as methylcellulose, can be used. In addition, naturally occurring thickeners and chemically synthesized thickeners can be used as caking agents.

In addition, as the dispersion solution added to the mixture consisting of binder pitch powder, coke powder and a caking agent, an organic solvent such as alcohol or water may be used. In addition, the volume content of carbon fiber with respect to the total volume of an intermediate material is 5-70 volume%, Preferably it is 20-60 volume%.

The intermediate | middle material (prepreg-shaped intermediate | middle material) of sheet form of this embodiment is manufactured through the following processes.

(1) Process of forming a mixed solution by mixing binder pitch powder, coke powder, a caking additive, and a dispersion solution at a predetermined compounding ratio.

(2) A step of uniformly dispersing short-fiber carbon fibers in the mixed solution by adding and mixing a predetermined mixed solution and short-fiber carbon fibers in the mixing tank.

(3) A step of papermaking by conveying a mixed solution in which short fiber carbon fibers are mixed and dispersed from a mixing tank into a papermaking apparatus belonging to a known technique.

In the sheet-shaped intermediate material (prepreg-shaped sheet) produced by the above process, the short-fiber carbon fibers are randomly oriented in the sheet plane and arranged in a nonwoven fabric in a entangled state. Furthermore, a continuous sheet-like nonwoven fabric composed of short pitch carbon fibers and binder pitch powder, coke powder, and a binder disposed around short fiber carbon fibers has a predetermined tackiness due to the binder mixed in the mixed solution. Has

Next, the invention which manufactures the spring element 1 using the sheet-shaped intermediate | middle material (prepreg-shaped sheet) demonstrated above is demonstrated.

2 shows a flowchart of a process of manufacturing a spring element 1 made of carbon / carbon composite material.

In the step 101 of forming a plate of carbon / carbon composite material or a preliminary plate of carbon / carbon composite material using a sheet-shaped intermediate material (prepreg-shaped sheet), a plurality of sheets produced by the above-described process The intermediate shape material (prepreg shaped sheet) is laminated and pressurized and heated using a hot press device or the like. When pressing and heating the laminated sheet, it is preferable to heat above the temperature at which the binder pitch powder softens, and to heat above the coking temperature of the binder pitch.

The pressurizing pressure for pressurizing the laminated sheets does not flow from the sheet-shaped intermediate material when the binder pitch powder is softened, and the sheet-shaped intermediate material (prepreg-shaped sheet) is adhered to and adhered between the laminates, and a compact molded body It is appropriately set to form a.

In the step 101 of forming a plate of carbon / carbon composites or a preliminary plate of carbon / carbon composites, the lamination is carried out above the temperature at which the binder pitch powder softens and above the coking temperature of the binder pitch. After the heat treated sheet is heat treated, the plate obtained by heat treatment can be carbonized and further graphite treated. In addition, a pitch impregnation process may be added between the above-described treatments, and the carbonization treatment and the graphite treatment may be repeated several times.

In step 101 of forming a plate of carbon / carbon composite material or a preliminary plate of carbon / carbon composite material, the preliminary plate is a plate of carbon / carbon composite material, for example, by a resin-char method. In the case of employing a process for producing a, it means a molded article (plate) containing a precursor of the step of curing the resin as a matrix (resin).

Next, in the step 102 of cutting out the annular shaped body, the plate of carbon / carbon composite material or the preliminary plate of carbon / carbon composite material obtained in step 101 is cut by machining and shown in FIG. 1. A molded article having an annular shape and a slit is formed.

As the cut molded body includes the slit 14, a molded body having a center angle of less than 360 degrees and having an annular shape is formed.

The shape of the cross section of the annular shaped body is rectangular, but is not limited thereto. Cross-sectional shapes with chamfers or rounded corners may also be used.

Next, in step 103 of spirally shaping the molded body having an annular shape, the molded body having an annular shape obtained in step 102 is supported by a jig, so that one end side 12 and the other end side 13 have a cross section. The spring element 1 is deformed by applying an external force so as to be separated in the central axis direction (X direction in FIG. 1), and the deformation of the molded body is maintained. By the process of step 103, the annular shaped body is shaped in a spiral as shown in FIG.

Next, in step 104 of heat-treating the molded body shaped to have a spirally annular shape, the molded body having the annular shape that is spirally shaped in step 103 is heat treated. The preferable temperature at which the molded body is heat treated is a temperature higher than the environmental temperature at which the spring element 1 is used. It is especially preferable to heat-process a molded object at the temperature of 1000 degreeC-3000 degreeC.

Further, in the step 104 of heat-treating the molded body having the shaped spiral toroidal shape, it is preferable to heat-treat the molded body in a state in which the molded body is supported by the jig to form an appropriate spirally annular shape of the molded body.

The torsional stiffness and shear strength of the spring element 1 manufactured by the manufacturing process using the sheet-shaped intermediate material (prepreg-shaped sheet) using the nonwoven fabric described here are as follows.

Torsional Rigidity 4560 Ncm ²

Shear Strength 54.6 MPa

Springs, manufactured by the same manufacturing process described above, using two-dimensional carbon / carbon composites having a layered configuration and alternately laminated at 0 degrees and 90 degrees using preformed yarns reinforced in one direction The bitrim stiffness and shear strength of the device 1 are as follows.

Torsional rigidity 997 Ncm ²

Shear Strength 13.7 MPa

These values represent the average of five test data, and the torsional stiffness is defined by the following equation.

Torsional Stiffness = Torsional Modulus × Polar Second Moment in Cross Section

In addition, the shear strength shown here shows the value obtained by loading a shear load to the washer-shaped test piece.

1: spring element
11: body part
12: one end
13: other end side
14: Slit

Claims (5)

A spring element having a spiral toric shape,
And wherein the spring element is a two-dimensional carbon / carbon composite material having a layer structure laminated in parallel with the surface of the spring element facing the spring axis direction of the spring element. The method of claim 1,
A spirally annular spring element having a layer structure in which the two-dimensional carbon / carbon composite material carbon fiber nonwoven fabric is laminated in parallel with the surface of the spring element facing the center axis direction of the spring element. As a manufacturing method of a spring element having a spiral toric shape,
Forming a plate of carbon / carbon composite material or a preliminary plate of carbon / carbon composite material having a layer structure formed by laminating a sheet unidirectionally oriented carbon fiber, a carbon fiber woven fabric, or a carbon fiber nonwoven fabric;
Cutting out the annular shaped body having a central angle of less than 360 degrees from the plate of carbon / carbon composite material or the preliminary plate of carbon / carbon composite material;
Spirally shaping the toroidal shaped body; And
Heat-treating the molded body having a spiral toric shape;
Spiral toroidal spring device manufacturing method comprising a The method of claim 3, wherein
Spiral ring-shaped spring element manufacturing method characterized in that the heat treatment temperature range is 1000 ℃ ~ 3000 ℃. The method according to claim 3 or 4,
The step of heat-treating the molded body having the spirally annular shape, the spiral annular spring element manufacturing method, characterized in that for heat treatment of the annular spring element while maintaining the shape of the spring element.

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