JP5592706B2 - Sheath heater lead wire connection terminal - Google Patents

Description

  The present invention relates to a lead wire connecting terminal of a sheathed heater that connects an end of a heating wire of a sheathed heater to a lead wire, and reduces thermal stress generated in the sheathed heater when heating and cooling are repeated, thereby generating thermal strain. The present invention relates to a lead wire connection terminal of a sheathed heater that suppresses and prevents early breakage of a connection portion.

  For example, there is a hot plate as a heating means using a sheath heater. This hot plate is obtained by embedding a sheath heater in a metal hot plate. In order to ensure the uniformity of the temperature distribution on the surface of the hot plate, a metal plate with good thermal conductivity is used, for example, a stainless plate or an aluminum plate. In particular, an aluminum hot plate is preferable because of its excellent thermal uniformity. Such a hot plate is used for industrial purposes, for example, for heating a substrate in a semiconductor substrate processing process.

  For example, a sheath heater is embedded in the heat plate. For example, a groove is formed in the heat plate, the sheath heater is accommodated in the groove, and a cover plate is attached to the surface side of the heat plate where the groove is provided. A stacked structure is common. For example, as a hot plate using such a sheath heater, those described in the following Patent Documents 1 to 5 are already known. As another form, aluminum or nickel is used as the material of the hot plate, a sheath heater is sandwiched between two grooved metal plates, and heat-sealed.

  In the hot plate as described above, a sheath heater using a stainless steel sheath has been used as a sheath heater embedded in the groove of the hot plate. However, so-called aluminum sheath heaters using an aluminum sheath having better thermal conductivity than a stainless steel sheath are used.

  Ni-Cr alloy wire (Nichrome wire) is used for the heating wire of the aluminum sheath heater, and the lead wire connected to this heating wire is made of stainless steel, nickel, Cu-Ni alloy (cupro nickel) like the stainless sheath heater. , White copper) or the like is used. In particular, as the lead wire, a thin rod-like body made of austenitic stainless steel such as SUS304 which has low thermal conductivity from the viewpoint of preventing heat dissipation and can be easily welded to the heating wire is used.

FIG. 6 shows a conventional example of a lead wire connection terminal of a sheath heater in which a heating wire of an aluminum sheath heater used as a heat source for a hot plate and a lead wire for connecting the power source thereof are connected. The aluminum sheath heater 103 is one in which a heating wire 110 is housed in a sheath 109 which is an aluminum protective tube, and an inorganic insulating material 111 such as magnesia powder is filled between the sheath 109 and the heating wire 110. An aluminum sheath heater 103 embedded in a hot plate of a panel heater (not shown) has its end pulled out from the cover plate 107 , and the heating wire 110 is connected to the lead wire 112 inside the sheath 109. This connecting portion is fixed by means such as welding.

  The aluminum sheath 109 of the aluminum sheath heater 103 has a larger thermal expansion coefficient than the austenitic stainless steel used as the lead wire 112. For this reason, if it is embedded in the hot plate up to the end of the lead wire 112 that is a non-heated portion and exposed to high heat, the thermal expansion of the heating wire 110 and the lead wire 112 during heating-cooling is reduced. Due to the difference, a large thermal stress is generated at the connecting portion between the heating wire 110 and the lead wire 112, particularly at the welded portion thereof. If heating and cooling of the hot plate are repeated in this state, the connecting portion between the heating wire 110 and the lead wire 112 may break early due to thermal strain accompanying the thermal stress, resulting in disconnection.

JP 2009-110881 A JP 2002-324655 A JP 2002-8835 A Japanese Patent Application Laid-Open No. 08-106973 JP 05-152060 A

  In the present invention, in view of the problem of the lead wire connecting terminal of the conventional sheath heater in which the heating wire and the lead wire of the aluminum sheath heater are connected, between the aluminum sheath and the end of the lead wire when heating and cooling are repeated. An object of the present invention is to make it difficult for thermal stress to occur, thereby suppressing thermal distortion and preventing early breakage and disconnection of the connection portion.

  In order to achieve the above object, in the lead wire connecting terminal of the sheath heater according to the present invention, the lead wire 12 is made of an aluminum thin wire, and nickel plating or nickel cladding 13 is applied to the end of the lead wire 12, The end of the heating wire 10 of the sheath heater 3 was connected to the nickel plated or nickel clad 13 portion. Thereby, the difference in thermal expansion between the aluminum sheath 9 and the aluminum lead wire 12 is eliminated, and the thermal stress is reduced.

That is, the configuration of the lead wire connection terminal of the sheath heater according to the present invention will be described in more detail with reference to the drawings. The lead wire connection terminal of the sheath heater is configured such that the end of the heating wire 10 of the sheath heater 3 is connected to the end of the sheath heater 3. The sheath 9 is connected to the end of the lead wire 12. The sheath 9 of the sheath heater 3 is made of aluminum, and the lead wire 12 is made of an aluminum thin wire. The end of the lead wire 12 is nickel-plated or nickel-clad 13, and the lead wire 12 is nickel-plated or nickel-clad. The end of the heating wire 10 of the sheath heater 3 is connected to the portion 13.

In such a lead wire connection terminal of the sheath heater according to the present invention, the sheath 9 of the sheath heater 3 is made of aluminum, the lead wire 12 is made of aluminum, and the end of the heating wire 10 of the sheath heater 3 is inside the aluminum sheath 9. Since the lead wire 12 is connected to the end of the aluminum lead wire 12 , when the heating wire 10 repeats heating and heating stop, the aluminum sheath 9 and the lead wire 12 repeatedly expand and contract simultaneously, and thermal stress is generated during that time. It is hard to do. For this reason, thermal distortion due to thermal stress is unlikely to occur, and early breakage and disconnection between the end of the heating wire 10 and the end of the lead wire 12 of the sheath heater 3 can be prevented.

  From the viewpoint of reducing the amount of heat radiation from the heating wire 10 side to the aluminum lead wire 12, it is preferable that the aluminum lead wire 12 be as thin as possible. On the other hand, it is preferable that the nickel plating or nickel cladding 13 applied to the end of the thin lead wire 12 is applied as thick as possible. The end of the heating wire 10 is connected to the nickel plating or nickel clad 13 by resistance welding 14 and fixed. Alternatively, the end of the heating wire 10 is connected to the nickel plated or nickel clad 13 portion, a nickel pipe 15 is fixed to the nickel plated or nickel clad 13 portion, and the pipe 15 is connected to the lead wire 12. The end of the heating wire 10 is covered.

  As described above, according to the present invention, since thermal stress is hardly generated between the aluminum sheath 9 and the end portion of the aluminum lead wire 12 when heating and cooling are repeated, thermal distortion is also unlikely to occur. As a result, it is possible to provide a lead wire connection terminal of the sheath heater in which the connection portion is not easily broken or disconnected early. Since the lead wire 12 made of aluminum has high thermal conductivity, heat radiation from the heating wire 10 to the lead wire 12 becomes a problem. However, by reducing the wire diameter of the lead wire 12 as much as possible, the heat transfer resistance is reduced. It is preferable that the heat dissipation from the heating wire 10 to the lead wire 12 is suppressed to some extent.

It is a top view which shows the example of the hotplate in which a sheath heater is used. It is a vertical side view of the hot plate, It is a principal part vertical side view of the same hot plate. It is a principal part vertical side view which shows one Example of the lead wire connecting terminal of the sheath heater by this invention. It is a principal part vertical side view which shows the other Example of the lead wire connecting terminal of the sheath heater by this invention. It is a principal part vertical side view which shows the prior art example of the lead wire connecting terminal of a sheathed heater.

In the present invention, the lead wire 12 is a thin aluminum wire, the end of the lead wire 12 is nickel-plated or nickel-clad 13, and the nickel-plated or nickel-clad 13 portion of the lead wire 12 is heated by the heating wire 10 of the sheath heater 3. Connect the ends of the.
Hereinafter, such embodiments of the present invention will be described in detail with specific examples with reference to the drawings.

FIG. 1 is a plan view showing an example of a hot plate in which a sheath heater is used, FIG. 2 is a longitudinal side view thereof, and FIG. 3 is an enlarged view of a main part thereof.
As shown in these drawings, the hot plate is a plate in which a groove 2 is provided on the lower surface of the hot plate 1 and a linear sheath heater 3 is embedded therein. For example, the hot plate 1 is for transferring the heat of the sheath heater 3 uniformly in the surface direction so that the surface of the hot plate 1 has a uniform temperature. For this reason, the hot plate 1 is made of a metal such as aluminum having good thermal conductivity, and has a disk shape in the illustrated example, but the shape of the object to be heated is selected according to the arrangement and the like.

  When a heated object such as a substrate is placed on the surface of the hot plate 1 and heated, the surface of the hot plate 1 may be coated so that the metal material forming the hot plate 1 does not react with the heated object. Such a coating is required to have heat resistance and to be chemically stable at high temperatures. For example, a ceramic coating such as alumina or boron nitride is optimal. The thickness of the coating is preferably about 100 μm.

  As shown in FIG. 3, a sheath heater 3 is used as the heater housed in the groove 2. The sheath heater 3 houses a coil-like heating wire 10 made of heat-resistant conductive wire such as nickel-chromium alloy wire or tungsten wire in a sheath 9 which is a tube-like protective tube made of aluminum. An inorganic insulating material 11 such as magnesia powder is filled between the wire 10 and the heating wire 10 and the sheath 9 are insulated.

  The sheath heater 3 is embedded and fixed in the groove 2 of the hot plate 1. A cover plate 7 having the same dimensions as the hot plate 1 is attached to the lower surface of the hot plate 1 so as to cover the opening of the groove 2. In the illustrated example, the cover plate 7 is fixed to the lower surface of the hot plate 1 by screws 8. The end of the sheath heater 3 is led out from the central hole of the cover plate 7.

  As shown in FIG. 2, the end of the sheath heater 3 embedded in the groove 2 of the hot plate 1 is pulled out from the groove 2 of the hot plate 1 through the cover plate 7 and includes a lead wire via the ceramic terminal 4. The sheath heater 3 is connected to a power source (not shown) via the lead cable 5. In FIG. 2, only the terminal of the sheath heater 3 on one side is shown, but both terminals of the sheath heater 3 are similarly connected.

  FIG. 4 shows an embodiment of the lead wire connection terminal of the sheath heater according to the present invention in which the end of the heating wire 10 of the sheath heater 3 is connected to the lead wire 12 of the lead cable 5. The lead wire 12 is made of an aluminum wire that is as thin as possible, and nickel plating 13 is applied to the end portion including the step portion into which the heating wire 10 is inserted. The nickel plating 13 is formed as thick as possible to several tens μm or more. The end portion of the lead wire 12 is a stepped portion that is thinned by one step, and the end portion of the heating wire 10 of the sheath heater 3 is fitted into this portion. And the edge part of the heating wire 10 is connected to the part of the nickel plating 13 by resistance welding. The nickel plating 13 in FIG. 4 is shown only up to the middle of the lead 12, but the nickel plating 13 may be applied over the entire length of the lead 12.

  Since the lead wire 12 made of aluminum has high thermal conductivity and good heat conductivity, it is made as thin as possible to increase heat transfer resistance and suppress heat radiation from the heating wire 10 side. Then, nickel plating 13 is applied as thick as possible to the end of the lead wire 12 to which the heating wire 10 is connected, so that the heating wire 10 can be easily connected.

  Further, nickel clad 13 can be applied instead of nickel plating 13. Here, the nickel clad 13 is formed by covering a thin nickel pipe on the lead wire 12 and bringing the nickel pipe into close contact with the lead wire 12 by plastic working such as Swages. The nickel clad has the same cross-sectional shape as the nickel plating, and the effects and effects of applying the nickel clad are the same as the nickel plating.

  FIG. 5 shows another embodiment of the lead wire connecting terminal of the sheath heater according to the present invention in which the end of the heating wire 10 of the sheath heater 3 is connected to the lead wire 12 of the lead cable 5. The end portion of the lead wire 12 is a stepped portion that is thinned by one step, and the end portion of the heating wire 10 of the sheath heater 3 is fitted into this portion as in the above-described embodiment. In this example, instead of resistance-welding the end of the heating wire 10 of the sheath heater 3 to the end of the lead wire 12, a nickel pipe 15 is fixed to the end of the lead wire 12, and the heat generated by the pipe 15 is connected. It covers the end of the line 10. The end portion of the heating wire 10 of the sheath heater 3 is inserted between the pipe 15 and the narrowed tip portion of the lead wire 12.

  The lead wire connection terminal of the sheath heater according to the present invention can be applied as a lead wire connection terminal of the sheath heater that connects the heating wire of the sheath heater and the lead wire, for example, in a hot plate in which the sheath heater is embedded and fixed in a metal hot plate. I can do it.

DESCRIPTION OF SYMBOLS 3 Sheath heater 10 Heating wire 12 of a sheath heater Lead wire 13 Nickel plating 14 Resistance welding 15 Nickel pipe

Claims (3)

At the lead wire connection terminal of the sheath heater (3), the end of the heating wire (10) of the sheath heater (3) is connected to the end of the lead wire (12) inside the sheath (9) of the sheath heater (3). The sheath (9) is made of aluminum, and a lead wire (12) is constituted by a thin aluminum wire, and nickel plating or nickel cladding (13) is applied to the end of the lead wire (12). The lead wire connecting terminal of the sheathed heater is characterized in that the end of the heating wire (10) of the sheathed heater (3) is connected to the nickel-plated or nickel-clad (13) portion. The lead wire connection terminal of the sheath heater according to claim 1, wherein an end portion of the heating wire (10) is resistance-welded to a nickel plating or nickel clad portion of the lead wire (12). The end of the heating wire (10) is characterized in that the pipe (15) is fixed so as to cover the end of the heating wire (10) on the nickel plating or nickel clad portion of the lead wire (12). The lead wire connection terminal of the sheath heater according to claim 1.

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