JPH02103885A - Heat generating device - Google Patents

Abstract

PURPOSE:To improve the electrical connection and to increase the mechanical strength by placing a connection member which consists of a heatproof conductive material with the rigidity lower than that of a C/C composite heating body between the terminal of the C/C composite heating body and an electrode. CONSTITUTION:Between the terminal 11a of a C/C composite heating body 11 and an electrode, a connection member which consists of a heatproof conductive material with the rigidity lower than that of said heating body 11 is placed. As the connection material, a sintered carbon; a high melting point metal such as Mo, W, Cr, Ti, Zr, and Ta; various sorts of heatproof alloys; a conductive ceramics such as a conductive nitride, a conductive metal silicate, and a conductive carbide; and moreover, a conductive cement or adhesive made by mixing the powder of those materials with a carbonic binder such as coal tar and coal tar pitch, a phenol resin, a furan resin, a KOPUNA [phonetic] resin; are used. When the terminal 11a and the electrode are connected, a washer is made from said material, for example, the washer is placed between the terminal and the electrode, and fastened with a screw nut and the like.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to carbon fiber/carbon composite (hereinafter referred to as C/C
This invention relates to a heat generating device using a composite (composite) as a heat generating element.

(Prior Art) Attempts have been made to use a C/C composite, which is a composite material in which the matrix is carbon (or graphite) and the reinforcing material is carbon fiber (or graphite fiber), as a heating element.

The present inventors have developed a surface heating element using this C/C composite, and have already published it in Japanese Patent Application No. 63-370.
No. 69 and Japanese Patent Application No. 63-37070.

When these C/C composites are used as heating elements, they can be processed into thin shapes and small diameters because of their high mechanical strength, and can be formed into small and precise shapes. Moreover, it is possible to generate high temperatures even when the current load is small. In that case, the C/C composite must be connected to an electrode that is a power supply path.

Conventionally, this connection has been achieved by, for example, making direct surface contact between the electrode and the terminal part of the C/C composite heating element, or making the electrode from a carbon material (or graphite material) and contacting the terminal part of the heating element with it. A method of simply screwing the two together or joining them with a conductive adhesive has been adopted.

(Problems to be Solved by the Invention) However, in the case of the connection method as described above, the following problems occur.

For example, if the terminals of the heating element and the electrodes are connected by directly contacting them, the heat conduction loss of the heating element will increase.
It becomes difficult to set a desired temperature distribution on the heating element. Further, in this connection, the terminal portion of the heating element and the electrode are in a mere surface contact state, so that the contact resistance becomes large. As a result, when electricity is applied, the temperature of this connecting portion increases and the electrode becomes hot. For example, if the electrode is made of metal such as copper, the electrode deteriorates and becomes worn out.

If the heating element is a C/C composite and the electrode is a carbon material, and the two are connected by screwing them together, the C/C composite generally has extremely high rigidity and lacks elasticity, so even if the screws are tightened, it will not work as the electrode. The problem arises that they are not compatible with the C/C composite, and that a sufficiently close connection cannot be achieved. Further, when a connection is made using a conductive adhesive, gas is generated from the adhesive even after the conductive adhesive is cured, resulting in a situation where the overall environment becomes poor.

An object of the present invention is to provide a heat generating device having a connecting portion between a C/C composite heat generating element and an electrode, which can solve the above-mentioned problems.

(Means/effects for solving the problem) In order to achieve the above object, in the present invention, C/C
Between the terminal part of the composite heating element and the electrode, the C/
There is provided a heat generating device characterized in that it has a connecting portion that connects the terminal portion and the electrode with a connecting member made of a heat-resistant conductive material having lower rigidity than the C composite heating element interposed therebetween.

The C/C composite which is a heating element can be manufactured by the following method.

The first method is the prepreg method. In this method, first, a prepreg is used, in which the carbon fiber described later is impregnated with a B-stage thermosetting resin such as phenolic resin or furan resin, or a carbonizable substance such as pitch, and the required number of prepregs are used. It is laminated or wound a necessary number of times to form a desired heating element shape.

Next, the obtained shaped body is fired at a temperature range of 600 to 3000°C in an inert gas atmosphere, and the carbonizable materials in the prepreg are thermally decomposed and carbonized or graphitized to form a C/C composite. to obtain a heating element. However, since the obtained heating element is porous and has a low density, it is preferable to repeat the operation of impregnating it with the carbonizable substance and firing it several times to increase the density until it reaches a predetermined density. .

The second method is a resin impregnation method. In this method, raw carbon fibers are laminated or wound and shaped into the shape of a heating element, and then impregnated with the above-mentioned carbonizable substance and fired. As in the case of the prepreg method, it is preferable to repeat the impregnation and firing process as necessary to increase the density.

The third method is the CVD method. In this method, as in the case of the resin impregnation method, raw carbon fibers are shaped into a heating element shape, and then heat treated in an air stream containing hydrocarbons such as methane and propane at a high temperature of 1000 to 2000°C. By doing so, the required amount of pyrolytic carbon (or graphite) is deposited on the surface of the carbon fiber to form a C/C composite,
This is a method of turning it into a heating element.

The fourth method is a blending method that can be applied to short fibers having a diameter of about 3 to 15 μm and an aspect ratio of several hundreds. In this method, various molding methods are applied to the mixture of the short fibers and the carbonizable substance,
After molding into the shape of a heating element, this is fired.

In the first to fourth methods described above, the heating element is shaped in advance into the shape of the heating element and then fired, but after firing, machining such as cutting may be performed to form the desired heating element shape.

The carbon fibers used in these methods include the following types.

The first is textiles. The woven fabric may be a plain woven fabric, a twill woven fabric, or a satin woven fabric. Further, circular woven fabrics or spiral circular woven fabrics disclosed in Japanese Patent Application Laid-Open No. 5158568 and Japanese Patent Publication No. 59-32291, respectively, can be used.

The second is a defibrated mat. In this case, each short carbon fiber is randomly oriented.

The third is chopped strand mat. This mat is made by cutting bundles of carbon fibers into predetermined lengths and setting each cut bundle in random orientation.

The fourth is the swirl cloak. This is not short fibers, but randomly oriented continuous fibers (or continuous fiber bundles) that may or may not be defibrated.

The fifth is a tubular braid. This is due to its radial and longitudinal extensibility. It can be used in its cylindrical form, or it can be crushed flat.

The sixth type is a unidirectionally aligned body of continuous fibers that are aligned parallel to each other in one direction in the form of a tape or sheet.

This is usually impregnated with a B-stage thermosetting resin such as phenolic resin, pitch, etc. to maintain the aligned state.

Separately, it is called unidirectional prepreg.

The seventh form is short fibers with a small aspect ratio, and is used when producing a heating element by the blending method described above.

In addition, when using the carbon fibers of the first to sixth embodiments described above in a layered manner, using carbon fiber threads and stiffening them together by, for example, single chain stitching, will improve the interlayer peel strength and interlayer shear of the heating element. This is preferable because strength, impact strength, etc. are improved.

The electrical resistance of the heating element depends on the type and form of the carbon fiber used,
The arrangement method, content, firing temperature when making carbon fiber, type of matrix carbon, bulk density of heating element, C/
It can be changed depending on the firing temperature, etc. when forming a C composite.

The electrode materials for supplying current to the C/C composite heating element mentioned above include commonly used Cu, N,...
In addition to materials with high electrical conductivity such as alloys such as stainless steel, for example, sintered carbon (or its graphitized product)
; Refractory metals such as Mo, W, Cr, TiZr, and Ta; various heat-resistant alloys, conductive nitrides such as BN; conductive metal silicides such as M6Six, B,
Materials that are both electrically conductive and heat resistant, typified by conductive carbides such as C, can be cited.

In the heat generating device of the present invention, a connecting member, which will be described later, is interposed between the terminal portion of the C/C composite heating element and the electrode to connect the two to form a connecting portion.

It goes without saying that the connecting member used here has electrical conductivity, but it also needs to have a property that its rigidity is lower than that of the C/C composite described above.

Examples of materials that satisfy such characteristics include the above-mentioned sintered carbon (or its graphitized product);

High-melting point metals such as W, Cr, T, Zr, and Ta; various heat-resistant alloys; conductive ceramics such as conductive nitrides, conductive metal silicides, and conductive carbides; and powders of these materials. , coal tar.

Examples include conductive cements and conductive adhesives made by kneading carbonaceous binders such as coal tar pitch and resin binders such as phenol resins, furan resins, and cobuna resins.

When connecting the terminals of the heating element and the electrodes, for example, a washer is manufactured from the above-mentioned material, this washer is interposed between the terminals and the electrodes, and the whole is secured by conventional means such as screws. All you have to do is tighten it up. Further, instead of the washer, a foam made of the above material may be used. Furthermore, apply the above-mentioned conductive adhesive to the terminal part or electrode,
After it is dried and hardened, the two can be tightened together using screws or other means.

In addition, a connecting member made of the above-mentioned material is bridged between the electrode and the terminal of the heating element, and one end of this connecting member and the electrode, and the other end of this connecting member and the terminal of the heating element. The parts may be tightened by means such as screws.

In the case of the former connection, the connection member has a rigidity of C/C
Since it is lower and softer than a composite, when the terminal part of the heating element and the electrode are tightened with a tightening means, a certain elastic force is generated by this connecting member, so that the connecting member is always attached to the heating element. Both the terminal portion of the heating element and the electrode are pressed in a direction opposite to the tightening direction, and as a result, the electrical connection state between the terminal portion of the heating element and the electrode at the connection portion is maintained well.

Also, in the case of the latter connection, the connection member whose both ends are pressed into contact with the electrode and the terminal of the heating element by the tightening means, has both ends tightly attached to the electrode and the terminal due to the elastic force. Therefore, the electrical connection between the electrode and the terminal portion of the heating element is maintained well.

(Example) Below, the connecting portion in the device of the present invention will be explained in more detail based on the accompanying drawings.

FIG. 1 is an exploded perspective view showing an example of a connecting portion according to the present invention. In the figure, the heating element 11 is a C/C composite plate whose heating part is bent in a zigzag manner, and a through hole 11b is formed in the terminal part 11a. The terminal portion 11a of this heating element is placed on the BN stand 12, which has a screw hole 12a formed in the upper part, with the through hole 11b and the screw hole 12a aligned.

A screw head 13c is provided in the through hole 11b and the screw hole 12a.
A male screw 13a is provided protruding from the bottom surface of the , and a screw hole 13b is provided from the top surface.
The screw 13 made of MO, which is formed with
It is strongly held between the upper surfaces of the N stand 12.

A through hole 14a is formed at the end of the upper surface of the screw head 13c, and a bus bar 14 made of Cu is plated with nickel.
is mounted, and a male screw 15a is formed in the through hole 14a and the screw hole 13b.

A screw 15 made of
The Cu bus bar 4 is strongly clamped by the lower surface of the cross head.

In the connection part of such a structure, the terminal part 1 of the heating element
Since the screw 1a is connected in close contact with the lower surface of the screw head 13c of the soft MO screw 13, the electrical connection between the Cu bus bar 14 and the heating element 11 is good.

FIG. 2 is an exploded perspective view illustrating a connecting portion between a C/C composite heating element and a carbonaceous electrode such as carbon when another connecting member is used.

In the figure, the terminal portion 21a of the heating element 21 has a through hole 21a.
is formed, and a through hole 22a is also formed at the end of the carbonaceous electrode 22.
is drilled. The connecting member 23 is made of a rod-shaped carbon or graphite material, and has through holes 23a and 23b formed at both ends thereof.

On the outer periphery of the two through holes 23a and 23b on one side of the connecting member 23, concave portions having a larger diameter than the screws 24a and 25a are formed concentrically, and these four portions are connected by a groove extending in the longitudinal direction. has been done. MO is incorporated and buried in the recesses and grooves of the through holes 23a and 23b.

The above-mentioned connecting member 23 is placed on the terminal portion 21a of the heating element and the electrode 22 so that the corresponding through holes match each other, and the male screws 24a and 25a are inserted into these through holes, respectively. It has a structure in which it is tightened with female screws 24b and 25b. In this case, the male thread and the female thread may be made of any material as long as they have heat resistance and conductivity.

In this case, the connecting member 23 has a structure in which the terminal part 21a of the heating element and the electrode 22 are bridged, and the terminal part 21a is in close contact with carbon or graphite material that is softer and has lower rigidity than the C/C composite in that part. Therefore, as in the case of FIG. 1, the electrical connection between the terminal portion 21a and the electrode 22 is good.

FIG. 3 is an exploded perspective view when the connecting member is a Mo foil. In the figure, a C/C composite heating element 31
Through holes 31b and 32a are formed in the terminal portion 31a of the terminal portion 31a and the end portion of the Cu electrode 32, respectively.
o foil 33 is placed, these are male threads 34 a,
35a, and are screwed together with female screws 34b and 35b. In this case as well, as in the case of FIG. 2, the material of the male and female threads does not matter as long as they have heat resistance and conductivity.

In this case, since the connecting member 33 is Moff3, its heat capacity is small, and therefore, the problem of heat conduction loss in which the amount of heat generated by the heating element 31 is transferred to the Cu electrode 32 side, which has a large heat capacity, is suppressed. As a result, the thermal efficiency of the heating element 31 can also be improved.

Figure 4 shows that the heating element has a trap shape and the electrodes are C/C.
FIG. 3 is an exploded perspective view illustrating a connection portion when it is a composite.

In the figure, the heating element 41 has a stationary shape, and its terminal portion 4
1a is pulled out in the shape of a foot, and a through hole Jlb is formed therein.

The tlfi 42 is also made of a c/c composite, but its specific resistance is smaller than that of the heating element 41. A through hole 42a is formed at the upper end of the electrode 42.

The connecting member 43 is made of a Mo board, and has a side plate part 43a formed at its upper part to hold the terminal part 41a of the heating element, and a side plate part 43a which is bent in the opposite direction to the side plate part 43a at its lower part. A side plate portion 43b that can hold the electrode 42 is formed. A through hole 43c is bored in the upper part of the Mo board.

When connecting, connect the terminal part 41a of the heating element to M.

The upper part of the plate and the upper part of the electrode 42 are connected to each other through holes 41b.

Overlap so that 43a and 42a match, M.

By bending the side plate portion 43b of the plate, the terminal portion 41. A is held, and in this state, a male screw 44 made of Mo is inserted into each through hole, and then screwed down with a female screw.

In this structure, since the soft MO plate 43 is interposed, the adhesion between the terminal portion 41b of the heating element and the electrode 42 is improved, and the electrical connection between them is not only improved, but also the Mo plate 43 The combined use of the C/C composite electrode 42 also provides the effect of reinforcing the mechanical strength of the terminal portion, llb.

(Effects of the Invention) As is clear from the above explanation, the connection part in the device of the present invention connects the terminal part of the C/C composite heating element and the electrode to the C/C composite heating element.
Since they are connected to each other through a connecting member made of a material with lower rigidity than the C/C composite, the electrical connection between the C/C composite heating element and the electrode is good, and heat generation at the connection part is suppressed. . Furthermore, since this connecting member is soft, it follows the shape during tightening and relieves stress concentration, thereby reinforcing the mechanical strength of the connecting portion. Furthermore, this connecting member can also restrict the flow of 4° heat from the heating element to the electrode side, and therefore exhibits the effect of increasing the thermal efficiency of the heating element.

[Brief explanation of the drawing]

1 to 4 are exploded perspective views showing structural examples of connecting portions formed by the method of the present invention. 11 21.31.41...C/C composite heating element, 11. a, 21a, 31a, 41a, . . . terminal portion of heating element, Ilb, 14a, 2]a, 22a. 23a 23b, 31a, 32a, 33a, 33b. 41b 42a 43cm through hole, 12・BN stand, 1.2 a, 13 b・= screw hole, 13, 1
5-M. screws, 22... carbonaceous electrodes, 24a, 25a34
a, 35 a, 44-male thread, 24b, 25b
34b 35b... Female thread, 33... Mo foil, 4
2...C/C composite tomet electrode, 43...Mo plate, 43a. 43b...Side plate part. Applicant: Hanawa Thermoelectric Metals Co., Ltd. Applicant: Toshi Co., Ltd. Company Representative: Patent Attorney Kan Nagato Figure 2

Claims (1)

[Claims] A connecting member made of a heat-resistant conductive material having lower rigidity than the carbon fiber/carbon composite heating element is interposed between the terminal part of the carbon fiber/carbon composite heating element and the electrode to connect the terminal part and the electrode. A heat generating device characterized in that it has a connection part consisting of.