JP4775019B2 - Manufacturing method of micro heater - Google Patents

Description

  The present invention relates to a connection structure of a microheater used for, for example, heat insulation of a pipe or a heating device in a vacuum device, and more specifically, a non-heating part so as not to generate heat in an extension part other than a required heating part. The present invention relates to a connection structure and a manufacturing method.

  The microheater has a flexible structure in which a heating wire is covered with a metal sheath through an insulating powder such as MgO, a terminal portion is attached to the end, heat tracing of piping, a heating device in a vacuum device, etc. Is used. Here, if the heating wire is inserted into the terminal portion, the terminal portion also generates heat. In particular, when pulling out from the vacuum apparatus, a penetrating metal fitting that vacuum seals the terminal portion with an O-ring is used. However, if the terminal portion generates heat, the penetrating metal fitting needs to be water-cooled to protect the O-ring. In recent years, when the size of the apparatus is increased, the number of micro heaters is increased, and thus the cost of the water cooling apparatus cannot be ignored.

  Therefore, the heat generation part of the micro heater is the same so that the terminal part does not generate heat, but a sheath cable (non-heat generation part) using a non-heat generation wire such as copper or nickel that does not easily generate heat is used instead of the heat generation line. A structure in which a terminal portion is provided at an end portion of the sheath cable, which is connected to a heater via a connection portion, is widely used (for example, see Patent Document 1).

  The microheater in which such a heat generating portion and a non-heat generating portion are connected has a connection structure as shown in FIG. 7, for example, and a heating wire 115 exposed from the heat generating portion 111 of the microheater and a sheath cable 114 are provided. After the non-heating wire 116 exposed from the wire is connected by welding or silver brazing, and the connecting sleeve 103 is attached to the metal sheath 113 of the heat generating portion by welding or silver brazing, insulating powder 104 such as MgO is sleeved 103 is filled with a vibrator or the like, and the plug 105 is attached to the sleeve 103 and the sheath cable 114 by welding or silver brazing. Further, the outer periphery of the sleeve 103 is pressurized with a press or the like to increase the packing density of the insulating powder 104 inside.

  However, in the conventional connection structure, the heat generating wire 115 and the non-heat generating wire 116 are connected by abutting, so that heat generation is likely to occur in the heat generating wire 115 when welded, and there is a hollow inside when silver brazing is performed. In some cases, a concentration stress on the joint due to expansion or contraction occurs due to use, and there is a problem that the connection strength or the electrical bondability is deteriorated. Insulating powder 104 in the sleeve is difficult to obtain a uniform filling density even if a vibrator or the like is used, and even if the outer periphery is pressed with a press or the like, it is equivalent to the insulating powder in the metal sheath of the heat generating part. You can't get density. If the same packing density as that of the heat generating portion 111 cannot be obtained in this way, the temperature of the heat generating wire 115 in the connecting portion becomes higher than the heat generating wire in the heat generating portion 111 during heat generation, which may cause disconnection in the connecting portion. Become. Furthermore, when the packing density of the insulating powder 104 is low, it causes a decrease in insulation at high temperatures.

  As a conventional example in which such a connecting portion is not provided, as shown in FIG. 8, when the heat generating wire 111 is manufactured by housing the heat generating wire in the metal sheath 113, the heat generating wire 115 is not heated in advance. An integral structure micro heater in which the wire 116 is connected and the non-heat generating portion 112 is formed together with the heat generating portion 111 is also used. In such an example, since it is a monolithic structure, there is no drawback of the connection part due to the above-mentioned but the length of the heat generating part 111 and the non-heat generating part 112 is set one by one according to the request each time. It had to be manufactured, lacked in flexibility of manufacturing, and there was a problem with delivery time and cost.

JP-A-2005-174582

  Therefore, in view of the above-mentioned situation, the present invention intends to solve the problem that a microheater in which a heat generating portion and a non-heat generating portion are connected maintains sufficient connection strength and good electrical connection between the heat generating wire and the non-heat generating wire. Microheater connection structure and manufacturing method that can prevent disconnection and insulation deterioration in the connection part, can flexibly set the length of the heat generating part and the non-heat generating part, and can avoid delivery problems and manufacturing cost problems Is to provide

  In order to solve the above-mentioned problem, the present invention accommodates a heating wire in a metal sheath and stores a non-heating wire in the metal sheath with respect to a heating portion formed by filling a gap with a heat-resistant insulating material. A connection structure of a microheater in which a non-heat generating portion filled with a heat-resistant insulating material is connected, wherein the heating wire protrudes from the end of the metal sheath of the heat generating portion and the end of the metal sheath of the non-heat generating portion. Provided with a cylindrical metal connector into which the non-heat-generating wires are respectively inserted, and a connecting sleeve that is sheathed between both metal sheath ends, and a heat-resistant insulation between the connector and the connecting sleeve By interposing an object and compressing and deforming the connecting sleeve radially inward, the heat resistant insulator is compressed, and at the same time, a connector is added radially inward through the heat resistant insulator. Pressed and inserted heating line and non-heating It provides a connection structure of a micro-heater, characterized by comprising by crimping, respectively.

  Here, it is preferable that the connector has a bottomed insertion hole for inserting the heating wire or the non-heating wire at both ends.

  Moreover, it is preferable that the said heat resistant insulator is a cylindrical molded object which compression-molded the heat resistant insulating powder.

  Furthermore, it is preferable that the molded body includes an inner peripheral surface and an outer peripheral surface that are loosely fitted to the outer peripheral surface of the connector and the inner peripheral surface of the connecting sleeve, respectively.

  Further, the connecting sleeve includes a thick portion protruding toward the outer peripheral surface side, and the thick portion protrudes toward the inner peripheral surface side until the outer peripheral surface of the connecting sleeve becomes substantially flat due to pressure deformation, thereby heat resistance. A connection structure in which a conductive insulator and a connector are pressurized is preferable.

  In particular, the dimension of the thick portion is set so that at least the pores of the heat-resistant insulator after pressure deformation are almost eliminated, depending on the porosity of the heat-resistant insulator and the size of excess voids in the connecting sleeve. What has been set is preferred.

  In addition, the present invention accommodates a heat generating wire in a metal sheath and a heat generating portion formed by filling a gap with a heat resistant insulating material, and stores a non-heat generating wire in the metal sheath and is similarly filled with a heat resistant insulating material. A method of manufacturing a microheater comprising a non-heat generating portion connected, wherein a heat generating wire protruding from a metal sheath end of the heat generating portion and a non-heat generating wire are inserted from the metal sheath end of the non-heat generating portion, respectively. A cylindrical metal connector, a connecting sleeve sheathed between both metal sheath ends, and a compression-molded heat-resistant insulating powder, and interposed between the connector and the connecting sleeve A cylindrical molded body, and a procedure for mounting the connector on one of the heat generating part or the non-heat generating part and mounting the molded body on the connector, The sleeve is attached to the end of the metal sheath and the molded body. Insert the other metal sheath end into the connecting sleeve and attach the non-heat generation wire or heat generation wire to the connector, and connect both ends of the connection sleeve to the outer peripheral surface of the metal sheath. The procedure is fixed by welding or brazing, and the connecting sleeve is compressed and deformed inward in the radial direction to compress the formed body, and at the same time, the connector is added radially inward through the formed body. There is also provided a method for manufacturing a microheater, comprising: a step of pressurizing and pressing the heat generating wire and the non-heat generating wire that are inserted and pressed.

  According to the present invention as described above, the heating wire and the non-heating wire are not but welded or silver brazed, and each wire is crimped to a metal connector and is electrically connected via the connector. Therefore, the length of each line can be set freely, the manufacturing flexibility and cost reduction can be achieved, and the strength reduction of the connection part and the electrical connection based on the fray and the cavity can be avoided, and it is uniform. A good electrical connection can be obtained.

  In addition, a heat-resistant insulator is interposed between the connector and the coupling sleeve, the coupling sleeve is pressed and deformed inward in the radial direction, and simultaneously with compression of the heat-resistant insulator, the heat-resistant insulator is interposed. The connector is pressed inward in the radial direction and crimped to the heating wire and non-heating wire, respectively, so that the bonding of the wire and the compression of the insulator can be performed efficiently at the same time. A uniform high filling density similar to that of the insulating powder in the metal sheath of the heat generating portion can be easily obtained, and disconnection and insulation deterioration due to use can be avoided in advance.

  In addition, since the connector has a bottomed insertion hole for inserting the heat generating wire or the non-heat generating wire at both ends, it is possible to reliably perform electrical joining by inserting each wire until it hits the bottom. This improves the workability of assembly.

  In addition, since the heat-resistant insulator is a cylindrical molded body obtained by compression-molding a heat-resistant insulating powder, a uniform packing density can be obtained and electrical insulation can be more reliably compared to those in which the powder is filled during assembly. In addition, since it only needs to be attached, the conventional filling operation of the insulating powder can be omitted, and the manufacturing cost can be reduced.

  Moreover, since the molded body has an inner peripheral surface and an outer peripheral surface that are loosely fitted to the outer peripheral surface of the connector and the inner peripheral surface of the connecting sleeve, the assembling work is facilitated.

  Further, the connecting sleeve has a thick portion protruding toward the outer peripheral surface side, and the thick portion protrudes toward the inner peripheral surface side until the outer peripheral surface of the connecting sleeve becomes substantially flat by pressure deformation, whereby heat resistant insulation Since it is a connection structure that pressurizes objects and connectors, the pressing force is determined by setting the dimensions of the thick-walled portion, and adjustment during pressurization is not necessary, and a good preset pressure state is obtained. Therefore, good and uniform quality and workability can be improved.

  Further, the dimension of the thick-walled portion was set so that at least the pores of the heat-resistant insulator after pressure deformation were almost eliminated according to the porosity of the heat-resistant insulator and the size of excess voids in the connecting sleeve. Therefore, the same uniform high packing density as that of the insulating powder in the metal sheath can be obtained, and a good insulating state can be obtained.

  Specific procedures include attaching the connector to one heating wire or non-heating wire of the heat generating portion or the non-heating portion, and mounting the molded body on the connector, and the end of the one metal sheath. A procedure for mounting the connecting sleeve on the part and the molded body, a procedure for inserting the other metal sheath end into the connecting sleeve, and attaching the non-heat generation wire or the heat generation wire to the connector, and both ends of the connection sleeve Are fixed to the outer peripheral surface of the end portion of the metal sheath by welding or brazing, and the connecting sleeve is compressed and deformed inward in the radial direction, and at the same time, the formed body is compressed. Thus, it is possible to manufacture a high-quality microheater easily and at low cost by pressing the connector inward in the radial direction and crimping each of the inserted heating wire and non-heating wire.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an explanatory view showing the configuration of a typical embodiment of a microheater according to the present invention, FIG. 2 is an explanatory view showing the main part of the connection structure, and in the figure, reference numeral 1 is a microheater, 2 is a connection A child, 3 is a connecting sleeve, and 4 is a heat-resistant insulator.

  As shown in FIG. 1, the microheater 1 accommodates a heat generating wire 15 in a metal sheath 13 and fills a gap with a heat-resistant insulating material. Is connected to a non-heat generating portion 12 filled with a heat-resistant insulating material, and a terminal portion 5 is provided at an end of the non-heat generating portion 12.

  As shown in FIG. 2A, the connection structure 10 of the microheater 1 according to the present invention includes a heating wire 15 protruding from the metal sheath end portion 13b of the heating portion 11 and the metal of the non-heating portion 12. Provided is a cylindrical metal connector 2 into which non-heating lines 16 protruding from the sheath end portion 14b are respectively inserted, and a connecting sleeve 3 is provided between the metal sheath end portions 13b, 14b. A heat-resistant insulator 4 is interposed between the connector 2 and the connecting sleeve 3, and the connecting sleeve 3 is deformed by pressure inward in the radial direction. At the same time as compressing the insulating insulator 4, the connector 2 is pressed inward in the radial direction via the heat-resistant insulator 4, and pressed onto the inserted heating wire 15 and non-heating wire 16. It is characterized by that.

  The heating wire 15 and the non-heating wire 16 can be made of the same material as the conventional one. The heating wire 15 can be made of nichrome, and the non-heating wire 16 can be made of nickel or copper. Also, the metal sheaths 13 and 14 can be made of stainless steel as in the prior art.

  As shown in FIG. 3, the connector 2 has bottomed insertion holes 20 and 21 in which the heat generating wire 15 or the non-heat generating wire 16 can be easily inserted at both ends, respectively. The reason why each of the bottomed insertion holes is provided in this way is to securely insert each line until it hits the bottom and perform electrical joining more reliably, but it is a through hole that communicates without being bottomed. Of course it is also possible. Such a connector 2 is preferably made of metal, particularly nickel or copper.

  As shown in FIG. 4, the heat-resistant insulator 4 is a cylindrical molded body 40 obtained by compression-molding a heat-resistant insulating powder made of MgO, BN or the like, and the molded body 40 is an outer peripheral surface of the connector 2. 22 and an inner peripheral surface 41 and an outer peripheral surface 42, which are loosely fitted to the inner peripheral surface 30 of the connecting sleeve 3, respectively. Since it is only necessary to assemble by forming the molded body 40 as described above, it is not necessary to fill and compress the powder as in the conventional case, the manufacturing becomes easy, and a uniform compression density can be obtained.

  The connecting sleeve 3 has an inner peripheral surface that fits on the outer peripheral surfaces of the metal sheaths 13 and 14, and has a thick portion 32 that protrudes toward the outer peripheral surface 31 at a position corresponding to the heat-resistant insulator 4 that is internally provided. A cylindrical metal member provided. The thickness of the thick portion 32 is such that the gap between the internal heat-resistant insulator 4 and the connector 2 and the metal sheaths 13 and 14, the gap between the connector 2 and the metal sheaths 13 and 14, and the connection 2 and each wire. It is set according to the size of the excess gap such as the gap and the pores of the heat-resistant insulator 4.

  Then, as shown in FIG. 2B, when the outer peripheral surface 31 of the connecting sleeve is uniformly deformed inward over the circumferential direction until the outer peripheral surface 31 of the connecting sleeve becomes substantially flat, the thick portion 32 becomes the inner peripheral surface 30. The heat-resistant insulator 4 and the connector 2 are also pressed inward with a uniform force in the circumferential direction by this protrusion, and the connector 2 and each wire are electrically connected, and the heat-resistant insulation The object 4 is compressed to eliminate pores, and the deformation fills the gaps between the metal sheaths 13 and 14 and the connector 2 to fill the surplus voids. FIG. 5 (a) is a cross-sectional view of the connecting portion before pressurization, and FIG. 5 (b) is a cross-sectional view of the connecting portion after pressurization. The molded body 40 is compressed and deformed.

  The thickness of the thick portion 32 of the connecting sleeve 3 is preferably such that the pores and voids after pressurization are eliminated, more preferably more than the pores of the heat resistant insulator are eliminated. Set to pulverize and compress particles.

  In addition, in this example, by setting such a thick portion 32, pressing can be performed as set by pressing until the outer peripheral surface becomes flat, and good electrical bonding and crimping strength can be reliably obtained. However, for example, pressure may be applied until the outer peripheral surface is further dented, and in this case, a cylindrical sleeve having a uniform thickness may be used without providing the thick portion 32. In the present embodiment, the thick portion 32 is continuously formed in the axial direction at a position corresponding to the connector 2, but it may have a continuous uneven shape, for example, the heating wire 15 attached to the connector 2, non-heating One or a plurality of ring-shaped or spiral convex portions are formed at positions corresponding to the lines 16 and the pressure-bonding strength is improved by intensively pressing instead of uniformly pressing in the axial direction. This is a preferred example.

  FIG. 6 is an explanatory diagram showing the assembly procedure up to the assembly state of FIG. 2A. First, after the insertion hole 20 of the connector 2 is attached to the heating wire 15 of the heating unit 11, the heat resistance is further increased. The molded body 40 of the conductive insulator 4 is packaged on the connector 2 (FIG. 6A).

  Next, after the connecting sleeve 3 is attached to the molded body 40 and the metal sheath 13 (FIG. 6B), the metal sheath 14 and the non-heat generating wire 16 of the non-heat generating portion 12 are connected to the connecting sleeve 3 and the inside. Before the outer peripheral surface of the connecting sleeve 3 is pressurized, both end portions 33 and 34 of the connecting sleeve 3 are welded to the outer peripheral surfaces of the metal sheaths 13 and 14, respectively. Or fix by brazing.

  In addition, before attaching the metal sheath 14 of the non-heating part 12 to the connection sleeve 3, the one end 33 may be fixed to the outer peripheral surface of the end of the metal sheath 13 in advance by welding or the like. Further, the assembling procedure is most efficient as shown in FIG. 6, but is not particularly limited thereto.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can of course be implemented in various forms without departing from the gist of the present invention.

Explanatory drawing which shows the microheater which concerns on embodiment of this invention. (A) is explanatory drawing which shows the principal part of the connection structure before pressure deformation, (b) is explanatory drawing which shows the principal part of the connection structure after pressure deformation. The longitudinal cross-sectional view which shows a connector. The longitudinal cross-sectional view which shows the molded object of a heat resistant insulator. (A) is a cross-sectional view showing the main part of the connection structure before pressure deformation, (b) is a cross-sectional view showing the main part of the connection structure after pressure deformation. (A)-(d) is explanatory drawing which shows an example of the assembly procedure of a connection structure similarly. Explanatory drawing which shows the conventional connection structure. Explanatory drawing which shows the other conventional micro heater.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microheater 2 Connector 3 Connecting sleeve 4 Heat resistant insulator 5 Terminal part 10 Connection structure 11 Heat generating part 12 Non-heat generating part 13 Metal sheath 13b End part 14 Metal sheath 14b End part 15 Heat generating line 16 Non-heat generating line 20, 21 Insertion Contact hole 22 Outer peripheral surface 30 Inner peripheral surface 31 Outer peripheral surface 32 Thick portion 33, 34 End 40 Molded body 41 Inner peripheral surface 42 Outer peripheral surface 103 Sleeve 104 Insulating powder 105 Plug 111 Heat generating portion 112 Non-heat generating portion 113 Metal sheath 114 Sheath Cable 115 Heating wire 116 Non-heating wire

Claims (2)

A heat generating wire is housed in a metal sheath, and a heat generating part is formed by filling a gap with a heat-resistant insulating material.
A non-heat generating wire is housed in a metal sheath, and a non-heat generating portion that is also filled with a heat-resistant insulating material is connected to a microheater manufacturing method, wherein the heat generating wire protrudes from the end of the metal sheath of the heat generating portion, And a cylindrical metal connector into which non-heating wires protruding from the metal sheath end of the non-heating portion are respectively inserted, and a thick portion protruding to the outer peripheral surface side, between the metal sheath ends A connecting sleeve that is sheathed, and a compression-molded heat-resistant insulating powder, constituting a cylindrical molded body interposed between the connector and the connecting sleeve,
A procedure of mounting the connector on one heating wire or non-heating wire of the heating portion or the non-heating portion and mounting a molded body on the connector,
A procedure for sheathing the connecting sleeve on the one metal sheath end and the molded body;
Inserting the other metal sheath end into the connecting sleeve and attaching the non-heat generation wire or the heat generation wire to the connector;
A procedure for fixing both ends of the connection sleeve to the outer peripheral surface of the metal sheath end by welding or brazing,
By pressing and deforming the connecting sleeve inward in the radial direction, the thick portion protrudes toward the inner peripheral surface until the outer peripheral surface of the connecting sleeve becomes substantially flat, thereby compressing the molded body. , A step of pressurizing the connector radially inward through the molded body, and crimping the inserted heating wire and the non-heating wire, respectively,
A method of manufacturing a microheater, comprising: The dimension of the thick part is set so that at least the pores of the heat-resistant insulator after pressure deformation are almost eliminated according to the porosity of the heat-resistant insulator and the size of the excess gap in the connecting sleeve. The method for producing a micro heater according to claim 1 .

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