JP2011075202A - Heater device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive defrosting heater facilitating assembly of glass tubes and a plug. <P>SOLUTION: The plug 7 is constituted of a body part 8 formed of hard plastic and an elastic part 9 formed of heat-resistant rubber such as silicone rubber. The elastic part 9 is mounted to a projection 8a provided in the body part 8, and the elastic part 9 is inserted to the inner glass tube 3 and the outer glass tube 4. Since the elastic part 9 absorbs variation of dimension tolerance of the glass tubes and is formed of the soft material and mounted to the body part 8 to prevent difficult insertion work, insertion work to the glass tubes 3, 4 is facilitated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heater device such as a defrost heater that melts frost that has adhered to and accumulated on a cooler of a refrigeration cycle mounted in a refrigerator or the like.

  Conventionally, this type of defrost heater has a glass tube containing a heater wire having a double structure in order to keep the surface temperature of the glass tube below a predetermined temperature (for example, the ignition point temperature of the flammable refrigerant). Both ends are sealed with rubber plugs (see, for example, Patent Document 1).

  FIG. 3 is a sectional view of a heater end portion showing a conventional defrosting heater described in Patent Document 1.

  As shown in FIG. 3, the defrost heater 20 includes an inner glass tube 21, an outer glass tube 22, a heater wire 23 housed in the inner glass tube 21, and the inner glass tube 21 and the outer glass tube 22. A rubber plug 24 that closes both ends and supports the heater wire 23 and a lead wire 25 that is connected to the heater wire 23 and led out to the outside.

  Since the plug 24 is in contact with a glass tube that becomes hot when the heater wire 23 is energized, silicon rubber having excellent heat resistance and chemical resistance is generally used.

  About the operation | movement of the defrost heater 20 comprised as mentioned above, the case where the defrost heater 20 is used for the refrigerator for home use is demonstrated to an example.

  The cooling chamber in which the defrost heater 20 is disposed is a place where moisture freezes with cooling and moisture evaporates with defrost heating, and in particular, glass inside and outside the defrost heater 20 with moisture evaporation. Moisture may enter the tubes 21 and 22.

  When moisture enters the inside of the defrosting heater 20, the heater wire 23 is exposed to high temperature and high humidity, so that it is easy to break. In particular, the defrost water contains various substances derived from food in the refrigerator, and also contains acids and alkalis that corrode the heater wire 23.

  Therefore, the defrosting heater 20 closes the outer glass tube 22 and the inner glass tube 21 with the plug 24 so as to prevent the defrosting water from entering the inside thereof with the stopper 24. Similarly, airtightness is also maintained in the lead wire 25 and the through portion of the plug 24.

Japanese Patent No. 3404389

  However, the above-described conventional configuration has a problem that workability for ensuring airtightness is poor in assembling the stopper 24 with the inner glass tube 21 and the outer glass tube 22.

That is, generally, the tolerance of the inner diameter or outer diameter of the glass tube is relatively different from the manufacturing process, unlike a molded product using a mold. The stopper 24 is designed with a considerable compression allowance in order to absorb the variation and maintain the hermeticity, but the compression allowance deteriorates the workability in the glass tube insertion work.

  The glass tube insertion portion 24a of the plug 24 has a large compression allowance so as to absorb the outer diameter tolerance of the inner glass tube 21 and the inner diameter tolerance of the outer glass tube 22, and is soft so that the insertion work can be easily performed. It is desirable to design with a material with reduced hardness.

  On the other hand, when the plug 24 is formed of a material with reduced hardness, the main body portion 24b into which the glass tube is not inserted becomes soft, and the main body portion 24b is deformed when the plug 24 is inserted into the glass tube. The insertion into the inner glass tube 21 and the outer glass tube 22 of 24a becomes difficult and may be in an insufficient insertion state.

  Further, the plug 24 formed of silicon rubber has a heat-resistant temperature of 200 ° C. or higher, and is an extremely expensive material among rubbers. In the above-mentioned conventional configuration, the amount of rubber used is large and very expensive.

  This invention solves the said conventional subject, and it aims at providing the defrost heater which is excellent in assembly property and can be comprised further cheaply.

  In order to solve the above conventional problems, a defrosting heater according to the present invention includes a glass tube, a heater wire made of a metal resistor disposed inside the glass tube and having lead wires connected to both ends, and the lead A plug through which the wire penetrates and which closes both end openings of the glass tube, and the plug is composed of a main body portion formed of a hard member such as heat-resistant plastic and an elastic member such as heat-resistant rubber. The glass tube is configured to have an elastic portion formed and attached so as to partially cover the main body portion, and the main body portion covered with the elastic portion is inserted into an opening of the glass tube. It is set as the structure which seals both the opening parts.

  As a result, when the plug is inserted into the glass tube, the elastic portion can be inserted into the opening of the glass tube while the elastic portion is supported by the main body of the plug, which is a hard (non-elastic) member. As a result, it is easy to attach the stopper to the glass tube, and the assembly workability can be improved.

  Further, the amount of the relatively expensive heat-resistant rubber used for the elastic member can be reduced, and most of the material can be replaced with a relatively inexpensive plastic, and an inexpensive defrosting heater can be provided.

  The heater device of the present invention can easily incorporate a stopper into a glass tube, and can provide an inexpensive heater device with improved workability and a reduced amount of heat-resistant elastic members.

The front view which sectioned a part of defrost heater in Embodiment 1 of this invention Sectional drawing of the principal part centering on the stopper of the defrost heater in Embodiment 2 of this invention Cross-sectional view of a conventional defrost heater

According to the first aspect of the present invention, there is provided a glass tube, a heater wire made of a metal resistor disposed inside the glass tube and having lead wires connected to both ends, the lead wire penetrates, and the glass tube A plug that closes the opening at both ends, and the plug is formed of a main body portion formed of a hard member such as heat-resistant plastic and an elastic member such as heat-resistant rubber, and the main body portion is partially A structure having an elastic portion attached to cover the glass tube, and a structure that seals both ends of the glass tube by inserting the main body covered with the elastic portion into the opening of the glass tube; It is what.

  By adopting such a configuration, in the operation of closing the glass tube with the plug, the elastic portion is elastically deformed, but the main body portion prevents the entire plug from being deformed, so that the plug can be easily inserted into the glass tube and assembled. Workability can be improved.

  In addition, since the insertion portion of the stopper into the glass tube has a structure in which the main body portion is covered with an elastic portion, the elastic portion is not displaced when inserted into the glass tube, and both end openings in the glass tube are opened. The sealing of the part can be ensured, and the penetration of water vapor or the like into the glass tube can be suppressed.

  According to a second aspect of the present invention, in the first aspect of the present invention, the glass tube is composed of an inner glass tube in which the heater wire is disposed, and an outer glass tube surrounding the inner glass tube. An elastic protrusion is provided along the surface of the protrusion, and the main body portion is provided with an annular protrusion that is inserted between the inner glass tube and the outer glass tube and maintains the distance between the inner glass tube and the outer glass tube. Is attached.

  By adopting such a configuration, it is possible to reduce the surface temperature of the outer glass tube accompanying the heat generation of the heater wire, and as a result, when the heater device is incorporated into a refrigeration cycle system using a combustible refrigerant, Even safety can be ensured.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the end portion of the glass tube is brought into contact with a peripheral step formed on the peripheral edge of the main body when the protrusion is formed. It is a thing.

  As a result, it is possible to further enhance the action of suppressing the penetration of water vapor or the like into the glass tube, and the corrosion of the heater wire can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a front view showing a cross section of a part of a defrosting heater according to Embodiment 1 of the present invention.

  In FIG. 1, a defrosting heater 1 includes a heater wire 2 formed of a metal resistor as is well known, an inner glass tube 3 having both ends opened, and an inner glass tube 3 containing the heater wire 2 therein, both ends opened, and an inner side. The outer glass tube 4 enclosing the glass tube 3, the lead wire 6 connected to both ends of the heater wire 2 via the connector 5, and the two ends sealing the inner glass tube 3 and the outer glass tube 4. A stopper 7 is provided.

  Here, as is well known, the lead wire 6 has a copper wire as a core, and the copper wire is covered with an elastic material having electrical insulation properties such as silicon rubber.

  The plug 7 includes a main body portion 8 made of hard plastic such as PPS having high heat resistance and an electric insulator, and an elastic portion made of rubber having high heat resistance and electric insulator such as silicon rubber. 9.

  The main body 8 covers an outer periphery of the inner glass tube 3 and is provided with an annular protrusion 8 a provided along the inner surface of the outer glass tube 4, an inner support portion 8 b that supports the inner glass tube 3, and a lead wire 6. Is provided with a drawer end 8c through which the cylinder penetrates and a cylindrical part 8d surrounding the drawer end 8c. Along with the formation of the annular protrusion 8 a, a peripheral step 8 e with which the end of the outer glass tube 4 abuts is formed on the outer peripheral edge of the main body 8.

  The elastic portion 9 is provided so as to cover the protrusion 8 a of the main body portion 8 and is inserted between the inner glass tube 3 and the outer glass tube 4, and the inner support portion 8 b and the inner side of the main body portion 8. An inner surface support portion 9b interposed between the glass tubes 3 and a through end portion 9c through which the lead wire 6 penetrates and inserted into the space of the drawer end portion 8c of the main body portion 8 are provided.

  Here, the inner diameter of the inner surface support portion 9b of the elastic portion 9 is set slightly smaller than the outer diameter of the inner glass tube 3, and the outer diameter of the insertion portion 9a is set slightly larger than the inner diameter of the outer glass tube 4. Attachment to the inner glass tube 3 and the outer glass tube 4 is facilitated by utilizing an appropriate compression action (compression degree) of the elastic portion 9.

  The elastic portion 9 is formed of a soft material (silicon rubber or the like) having a hardness of about 35 to 60 degrees, for example, and the inner glass tube 3 and the outer glass tube 4 have a large dimensional variation, and can be inserted even if the degree of compression increases. Hardness is selected so that the strength does not become too large.

  Next, an example of assembly of the defrost heater 1 will be described.

  The inner glass tube 3 is inserted into the outer glass tube 4, and the heater wire 2 to which the lead wire 6 is connected is disposed in the inner glass tube 3. In that state, the lead wire 6 of the heater wire 2 disposed in the inner glass 3 is passed through the plug 7 in which the main body portion 8 and the elastic portion 9 are combined in advance. Therefore, the lead wire 6 is in a state of penetrating the through end portion 9 c of the elastic portion 9 and the lead-out end portion 8 c of the main body portion 8.

  Then, the inner surface support portion 9 b is inserted into the inner glass tube 3 while the cylindrical portion 8 d of the one plug 7 is supported, and then the insertion portion 9 a (protrusion 8 a) is inserted into the outer glass tube 4. Similarly, for the other stopper 7, the inner surface support portion 9 b is inserted into the inner glass tube 3, and then the insertion portion 9 a (protrusion 8 a) is inserted into the outer glass tube 4.

  The plug 7 is inserted into the inner glass tube 3 and the outer glass tube 4 by the compression action of the elastic portion 9 selected to have an appropriate hardness as described above and the support of the elastic portion 9 by the hard main body portion 8. 7 itself can be deformed by the deformation (compression) action of the elastic portion 9, and the attaching operation becomes extremely easy.

  Therefore, by configuring the plug 7 with the hard main body 8 and the soft elastic portion 9, the main body 8 can be prevented from being deformed during the glass tube insertion work, and the defrosting heater 1 with good insertion workability is supplied. can do.

  Moreover, the usage-amount of the expensive rubber used for the elastic part 9 can be reduced, and a defrost heater can be supplied cheaply.

  Furthermore, the defrosting heater 1 can reduce the surface temperature of the outer glass tube 4 accompanying the heat generation of the heater wire 2 by adopting a double glass tube structure including the inner glass tube 3 and the outer glass tube 4. As a result, safety can be ensured even when the defrosting heater 1 is incorporated into a refrigeration cycle system using a flammable refrigerant.

  Moreover, since the defrost heater 1 makes the edge part of the outer side glass tube 4 contact | abut to the peripheral step part 8e formed in the periphery of the main-body part 8 with formation of the processus | protrusion 8e, it is outside glass, such as water vapor | steam. It is possible to further enhance the effect of suppressing intrusion into the tube 4 and to suppress the corrosion of the heater wire 2.

  Furthermore, in the lead-out end portion 8e, the diameter of the hole through which the lead wire 6 penetrates is set to a dimension that can provide appropriate adhesion to the lead wire 6 by using the compressing action of the covering material. It can be expected that the defrosting heater 1 is configured at low cost by using an inexpensive resin material such as vinyl chloride.

  That is, the heat of the heater wire 2 is transmitted to the lead wire 6 through the connector 5, but the covering of the lead wire 6 and the lead-out end portion 8e of the plug 7 made of hard plastic are in close contact as described above. In addition, as the thermal conductivity of the hard plastic is higher than that of silicon rubber or the like, the heat of the heater wire 2 is quickly radiated from the surface through the main body portion 8 formed of the hard plastic.

  Accordingly, the temperature heating (rise) of the plug 7 is suppressed, and the temperature of the plug 7 can be maintained below the melting temperature of an inexpensive resin material such as vinyl chloride, and the lead wire 6 is covered with a low price such as vinyl chloride. It can be expected that the defrosting heater 1 is configured at low cost by using a simple resin material.

  In the first embodiment, the defrosting heater having a so-called double glass tube structure including the inner glass tube 3 and the outer glass tube 4 has been described. However, the heater wire is disposed in a single glass tube. The frost heater can be implemented in the same manner, and the same effect can be expected.

(Embodiment 2)
FIG. 2 is a cross-sectional view of the main part centering on the plug of the defrosting heater in Embodiment 2 of the present invention. In the second embodiment, the configuration different from that of the first embodiment will be mainly described, and the same components as those of the first embodiment will be described with the same reference numerals.

  In FIG. 2, the plug 7 a has a configuration in which the main body portion 18 and the elastic portion 9 made of the same material as in the first embodiment are combined, and the shape of the main body portion 18 is different from that in the first embodiment.

  The main body portion 18 in the second embodiment has a minimum necessary configuration by omitting the cylindrical portion 8d of the main body portion 8 in the first embodiment, and has a configuration in which the leading end portion 8c is exposed.

  Even in such a configuration, the defrosting heater 1 can be assembled similarly to the first embodiment, and in addition to the same effects as the first embodiment, the plug 7 can be downsized and the material cost of the main body 18 can be reduced. I can expect.

  As described above, the heater device according to the present invention is easy to assemble and can be configured at low cost, and is adapted for use in an article storage device such as a refrigerator, or a device having a cooler such as a transport machine or an environmental test machine. be able to.

DESCRIPTION OF SYMBOLS 1 Defrost heater 2 Heater wire 3 Inner glass tube 4 Outer glass tube 6 Lead wire 7 Plug 8 Body part 8a Projection 8e Periphery step part 9 Elastic part

Claims (3)

A glass tube, a heater wire made of a metal resistor disposed inside the glass tube and having lead wires connected to both ends thereof, and a plug through which the lead wire penetrates and which closes both end openings of the glass tube The plug is made of a body part formed of a hard member such as heat-resistant plastic, and an elastic member formed of an elastic member such as heat-resistant rubber, and is attached so as to partially cover the body part. A heater device having a structure in which both ends of the glass tube are sealed by inserting a main body covered with the elastic portion into the opening of the glass tube. The glass tube is composed of an inner glass tube in which the heater wire is arranged and an outer glass tube surrounding the inner glass tube, and is inserted between the inner glass tube and the outer glass tube into a main body portion constituting the stopper. 2. The heater device according to claim 1, wherein an annular protrusion is provided to maintain a distance between the inner glass tube and the outer glass tube, and the elastic portion is attached along a surface of the protrusion. The heater device according to claim 1 or 2, wherein an end portion of the glass tube is brought into contact with a peripheral step portion formed at a peripheral portion of the main body portion with the formation of the protrusion.