JP2011022005A - Method of removing coating material in sheath structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of removing a coating material of a sheath structure capable of removing the coating material of a sheath structure at low costs without performing two processes of different property. <P>SOLUTION: In the method of removing a coating material of a sheath structure, the circumference of a metal lead wire 23 is filled with inorganic insulator powder 22, the outer periphery is covered with a metal protecting tube 21, and the coating material is composed of the inorganic insulator powder 22 and the metal protecting pipe 21. The method includes the rough machining process for cutting the coating material with a relative large amount of feed and the finish machining process for cutting the coating material with a relative small amount of feed after the rough machining process. The cutting in the rough machining process is performed while applying ultrasonic vibration to a cutting tool. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sheath material removing method for a sheath structure, and more particularly to a sheath material removing method for exposing a metal wire embedded in a sheath structure in order to manufacture a sheath type thermistor, a sheath type thermocouple, or the like.

  The sheath structure has a structure in which a metal wire is filled with an inorganic insulating powder such as magnesium oxide (hereinafter referred to as insulating powder) and the outer periphery thereof is covered with a metal protective tube. When manufacturing a sheath type thermistor or thermocouple from such a sheath structure, an insulator powder, a metal protective tube, or the like that covers a metal wire such as a lead wire or thermocouple wire at the end of the sheath structure It is necessary to remove the covering material. Conventionally, after removing the metal protective tube and some of the insulating powder by cutting, the remaining insulating powder is removed by shot blasting to expose the metal wire.

  Patent Document 1 discloses a method of removing the insulating powder around the metal wire by laser beam irradiation after cutting off the metal protective tube.

JP-A-11-337418

  However, the above-described conventional method has a problem of high cost because it requires two different steps of cutting and shot blasting to remove the covering material.

  Therefore, the present invention solves such a problem, and provides a sheath structure covering material removal method capable of removing a sheath structure covering material at low cost without performing two different steps. The purpose is to do.

  In order to achieve the above object, according to the first aspect of the present invention, the inorganic insulating powder (22) is filled around the metal wire (23), and the outer periphery thereof is covered with the metal protective tube (21). A sheath material removing method for a sheath structure in which a covering material is constituted by powder (22) and a metal protective tube (21), the roughing step of cutting the covering material with a relatively large feed amount, And a finishing process that cuts the covering material with a relatively small feed amount following the machining process, and at least the cutting in the roughing process is performed while applying vibration to the cutting tool (4). And

  In the first invention, the inorganic insulating powder is pulverized simultaneously with the cutting of the metal protective tube by cutting while applying vibration to the cutting tool at least in the roughing step. Thereby, inorganic insulating powder is also removed favorably by cutting in the subsequent finishing process. According to the first aspect of the present invention, the sheath material can be removed from the sheath structure at low cost only by cutting. The vibration is preferably by ultrasonic vibration.

  In the second invention, in the first invention, a pair of the metal wires (23) are inserted into the metal protective tube (21) substantially in parallel. In the second aspect of the invention, at least in the roughing process, cutting is performed while applying vibration to the cutting tool, so that only the inorganic insulating powder between them is satisfactorily removed without twisting the pair of metal wires.

  In the third invention, the inorganic insulating powder (22) is filled around the metal wire (23), the outer periphery thereof is covered with the metal protective tube (21), and the inorganic insulating powder (22) and the metal protective tube are covered. (21) is a method for removing a covering material of a sheath structure, in which the covering material is cut, and the covering material is cut and removed while applying vibration to the cutting tool (4).

  The reference numerals in the parentheses indicate the correspondence with specific means described in the embodiments described later.

  As described above, according to the sheath material covering material removal method of the present invention, without using two different processes of cutting and shot blasting as in the prior art, the cost of the sheath structure can be reduced only by cutting. The coating material can be removed.

1 is an overall side view of a sheath type temperature sensor to which a method of the present invention is applied. It is sectional drawing of a sheath structure. It is a side view of the both ends of the sheath structure which exposed the metal lead wire. It is whole sectional drawing of the cutting tool used for this invention method.

  FIG. 1 shows a side view of a sheath type temperature sensor to which the method of the present invention is applied. In this embodiment, a case where the temperature sensor is a thermistor will be described. In FIG. 1, a sheath type thermistor 1 includes a round bar-shaped sheath structure 2 having an outer diameter of about 3 mmφ. FIG. 2 shows a cross section of the sheath structure 2. In the sheath structure 2, an insulating powder 22 made of magnesium oxide (magnesia) or the like is filled in a cylindrical metal protective tube 21 such as SUS310S, and a pair of metal lead wires 23 such as SUS310S are embedded therein. It is configured.

  In FIG. 1, a cap portion 3 is welded to the outer periphery of the distal end portion of the sheath structure 2, and the thermistor element is interposed between metal lead wires 23 (FIG. 2) exposed in the cap portion 3 by a method described later. Is welded. The base end portion of the sheath structure 2 is inserted into the vibration suppression pipe 11 and then reaches the attachment member 12. The attachment member 12 has a screw part 121 and a hexagonal rotation operation part 122 formed on the outer periphery.

  Also at the proximal end of the sheath structure 2 located in the attachment member 12, metal lead wires 23 as metal wires are exposed by a method described later, and these metal lead wires 23 are inserted into the attachment member 12. It is connected to the core wire of the signal cable 13. In the case where the temperature sensor is a thermocouple, the pair of metal lead wires are thermocouple wires, and the tips of the thermocouple wires exposed by the method described later are connected to each other with a temperature measuring point. To do.

  When the sheath type thermistor 1 is manufactured, as shown in FIG. 3, the insulating powder 22 covering the metal lead wire 23 and the metal protective tube 21 are formed at both ends of the sheath structure 2 as described above. The covering material is removed to expose the metal lead wire 23. Conventionally, this has been performed by two different processes of cutting (turning) and shot blasting, but in the present embodiment, it is realized at low cost by vibration turning described below.

  FIG. 4 shows an example of the cutting tool 4 used in this embodiment. In FIG. 4, the bite shank 41 also serves as a vibrator horn, and semicircular electrostrictive elements 42 and 43 are sandwiched between upper and lower half portions 411 and 412. A bit holder 45 having the same diameter is coupled to the small diameter portion 44 of the bit shank 41 by a fastening ring 46, and a tip bit 47 is attached to the tip of the bit holder 45. The tip bite 47 is vibrated by energizing the upper and lower electrostrictive elements 42 and 43 during turning and alternately expanding and contracting them.

  Therefore, the cutting tool 4 was used to perform a roughing process and a finishing process as shown in the following examples and comparative examples. The outer diameter of the sheath structure 2 to be processed was 2.95 mmφ, and the turning amount was 1.2 mmφ. The vibration frequency of the tip bit 47 was 19.5 KHz, the vibration piece amplitude was 15 μm, and the rake angle of the tip bit 47 was 30 °.

  In Example 1 of Table 1, vibration turning was performed by vibrating the tip bite in the roughing process, and normal turning was performed without vibrating the tip bite in the finishing process. Table 1 shows the number of turning rotations, feed amount per revolution, cutting amount, turning speed, and machining time in each step in this example. As a result of the processing, the metal protector and the insulator powder were completely removed, and only the metal lead wire was exposed.

  In Example 2 of Table 1, the tip turning was vibrated to perform vibration turning in both the roughing process and the finishing process. Table 1 shows the number of turning rotations, feed amount per revolution, cutting amount, turning speed, and machining time in each step in this example. As a result of the processing, the metal protector and the insulator powder were completely removed, and only the metal lead wire was exposed. However, the processing time is as long as 15.41 seconds compared to 14.33 seconds in Example 1.

  In Comparative Example 1 of Table 1, normal turning without vibrating the cutting tool was performed in the roughing process, and vibration turning was performed by vibrating the cutting tool in the finishing process. Table 1 shows the turning speed, feed amount per rotation, cutting amount, turning speed, and machining time in each process in this comparative example. As a result of the processing, a part of the insulating powder adhered to the metal lead wire and was not completely removed.

  In Comparative Example 2 in Table 1, ordinary turning was performed without causing the tool bit to vibrate in either the roughing process or the finishing process. Table 1 shows the turning speed, feed amount per revolution, cutting amount, turning speed, and machining time in each process of this comparative example. As a result of the processing, the insulating powder was not removed at all and remained attached to the metal lead wire.

  In the above embodiment, all processes may be processed with the same feed amount without being divided into a roughing process and a finishing process with different feed amounts. In this case, the vibration is applied in all steps, or is appropriately performed in the first half of the steps.

DESCRIPTION OF SYMBOLS 2 ... Sheath structure, 21 ... Metal protective tube, 22 ... Inorganic insulator powder, 23 ... Metal lead wire (metal wire), 4 ... Cutting tool.

Claims (3)

A sheath material removal method for a sheath structure in which a metal wire is filled with an inorganic insulator powder, the outer periphery thereof is covered with a metal protective tube, and the sheath material is constituted by the inorganic insulator powder and the metal protective tube. A roughing process for cutting the covering material with a relatively large feed amount; and a finishing process step for cutting the covering material with a relatively small feed amount following the roughing process. A sheath structure removing method for a sheath structure, wherein cutting in a machining process is performed while applying vibration to a cutting tool. The said metal wire is a coating | covering material removal method of Claim 1 with which a pair is penetrated in the metal protective tube substantially in parallel. A sheath material removal method for a sheath structure in which a metal wire is filled with an inorganic insulator powder, the outer periphery thereof is covered with a metal protective tube, and the sheath material is constituted by the inorganic insulator powder and the metal protective tube. A method for removing a covering material from a sheath structure, wherein the covering material is removed by cutting while applying vibration to a cutting tool.

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