KR20130071922A

KR20130071922A - An automatic drawing door having a autowinder for wire protecting tube and a refrigerator thereof

Info

Publication number: KR20130071922A
Application number: KR1020110139408A
Authority: KR
Inventors: 김명환; 유대현
Original assignee: 엘지전자 주식회사
Priority date: 2011-12-21
Filing date: 2011-12-21
Publication date: 2013-07-01

Abstract

The present invention is a self-winding door using a self-winding device and a self-winding wire using a wire protection tube to improve the durability by preventing the breakage of the wire when pulling out and winding the wire in the automatic winding device in the refrigerator equipped with the same The present invention relates to a self-drawing door equipped with a device and a refrigerator having the same.
The present invention is mounted on the inside of the door of the refrigerator, the drive unit for automatically opening and closing the door in the drawer method; A wire that is a conductive wire for supplying power to the drive unit; A protective tube made by insert injection and protected by wrapping the wire; And an automatic winding device, in which the wire is unwound when the door is opened and the wire is automatically wound when the door is closed, the automatic retracting device equipped with the automatic winding device using a wire protection tube.

Description

Automatic retractable door with automatic winding device using wire protection tube and refrigerator with same {AN AUTOMATIC DRAWING DOOR HAVING A AUTOWINDER FOR WIRE PROTECTING TUBE AND A REFRIGERATOR THEREOF}

The present invention is a self-winding door using a self-winding device and a self-winding wire using a wire protection tube to improve the durability by preventing the breakage of the wire when pulling out and winding the wire in the automatic winding device in the refrigerator equipped with the same The present invention relates to a self-drawing door equipped with a device and a refrigerator having the same.

The refrigerator is a home appliance that is provided with a storage space shielded by a refrigerator door and stores food at a low temperature in the storage space. Such a refrigerator allows the food stored in the storage space to be optimally stored using cold air generated through heat exchange of a refrigerant circulating in a refrigeration cycle. Recently, in addition to the basic functions of the refrigerator, various functions have been added to increase the user's convenience, and the automatic retractable door is a kind of such function.

The automatic draw-out door is a conventional method in which an actuator is added to a door that is directly opened and closed by a user so that the door can be opened and closed by a driving force of an actuator rather than an attraction force, and is mainly used in a drawer type door called a drawer. This is because the drawer-type door is pulled out together, which requires more force to open and close the door of a conventional refrigerator.

As an actuator for drawing out the drawer, a drive motor is usually used, and a conductor for applying electric power to the drive motor is necessarily connected to the drive motor.

At this time, since the drawer type drawer-type door is drawn out and is connected from the power source for a long time, the lead wire is extended to be connected to the driving motor, and the connected wire may be twisted or broken during opening and closing of the door.

In addition, even in the wire protection using the chain as described above, the wire at the portion connected to the actuator is not protected by the chain, and a problem such as cutting or breaking may be caused by a tensile force.

The present invention is to solve the problems of the prior art as described above, has the following object.

An object of the present invention, the self-winding door equipped with an automatic winding device using a wire protection tube to improve the durability by fixing the wire firmly in the automatic winding device to prevent breakage of the wire during the extraction and winding of the wire and having the same To provide a refrigerator.

Another object of the present invention is equipped with a self-winding device using a wire protection tube to protect the wire by a protective tube made by insert injection to prevent the wire from being peeled or crushed during the door draw operation It is to provide a self-drawing door.

In order to achieve the above-mentioned object, the present invention will be realized by an embodiment having the following constitution as a preferred embodiment.

According to one embodiment of the invention, the present invention is mounted on the inside of the door of the refrigerator, the drive unit for automatically opening and closing the door in the drawer method; A wire that is a conductive wire for supplying power to the drive unit; A protective tube made by insert injection and protected by wrapping the wire; And an automatic winding device, in which the wire is unwound when the door is opened and the wire is automatically wound when the door is closed, the automatic retracting device equipped with the automatic winding device using a wire protection tube.

The automatic winding device may include: a housing in which wires are pulled out and drawn out or wound; A leaf spring having an elastic restoring force in a rotational direction; A rotating plate to which the leaf spring is mounted and rotates so that the wire is wound; And a winding shaft in which one end of the leaf spring is fixed inside the housing.

And, the rotating plate, the hook projection is wound around the wire protection tube is fixed; includes, the wire which is protected by the protection tube is drawn out to the outer periphery of the rotating plate; to include.

In addition, the rotating plate, the inner wall and the outer wall, the outlet hole is formed in the outer wall, the wire is wound on the engaging projection to be drawn out through the outlet hole.

According to another embodiment of the present invention, the protective tube, a folding cutout portion that is cut one side on the cross-section of the protective tube to the wire folding portion.

Thus, the folded cutout may be formed in plural at regular intervals in the inner circumferential direction in which the wire is wound.

According to another embodiment of the present invention, the present invention provides a refrigerator body having a refrigerating compartment and a freezing compartment therein; A refrigerator compartment door to open and close the refrigerator compartment; A freezing chamber door formed at a lower portion of the refrigerator body and opened and closed by a drawer type; A driving unit mounted inside the freezing compartment door and automatically opening and closing the freezing compartment door in a drawer manner; A wire that is a conductive wire for supplying power to the drive unit; A protective tube made by insert injection and protected by wrapping the wire; And an automatic winding device in which the wire is unwound when the door is opened and the wire is automatically wound when the door is closed.

Accordingly, the protective tube may be formed in a shape in which one side is cut in cross section, and a plurality of folded cutout portions formed at a predetermined interval in an inner circumferential direction in which the wire is wound.

A wire that is a wire for supplying power to a drive unit that automatically opens and closes a drawer-type refrigerator door; And a protective tube manufactured by insert injection and protected by wrapping the wire.

According to another embodiment of the present invention, the protective tube is a built-in wound on the automatic winding device of the wire when the door is closed, including; When the door is opened, it is unwound to provide a wire to be drawn out.

Thus, the folding incision portion is formed in a plurality at regular intervals in the inner circumferential direction in which the wire is wound so that the wire integrated with the insert injection protection tube is easily wound on the winding device.

According to the aspects of the present invention having the configuration as described above, the present invention improves durability by firmly fixing the wire during the automatic winding device operation of the drawer-type door to prevent breakage of the wire when pulling out and winding the wire In order to prevent the wire coating from peeling off or crushing during the door's drawing operation, the wire can be protected by a protective tube made by insert injection.

The present invention can also be economical by minimizing unnecessary space by forming a protective tube of the wire as an insert injection molding and forming a folded cutout in the inner portion of the wire wound to compact the protective structure.

The present invention can also improve the durability and convenience of the product by preventing the wire from being broken or broken when the wire is subjected to a tensile force while being folded or twisted by forming a wrap around the entire wire wound and unwound by the automatic winding device.

1 is an elevational view showing a refrigerator provided with a retractable door equipped with a winding-up device of the present invention.
Figure 2 is a perspective view of the self-winding door is equipped with a winding device of the present invention.
Figure 3 is a perspective view showing a drawer type door is equipped with a winding control device of the present invention.
Figure 4 is a detailed view showing a leaf spring inside the automatic winding apparatus of the present invention.
Figure 5 is a detailed view showing a structure in which a wire having a protective tube of the present invention is fixed in the rotating plate.
Figure 6 is a detailed view of the wire produced by the bendable protective tube of the present invention.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the self-winding door equipped with an automatic winding device using a wire protection tube according to the present invention and a refrigerator having the same.

Prior to this, terms and words used in the present specification and claims should not be construed as being limited to ordinary or dictionary terms, and the inventor should appropriately define the concept of the term to describe its invention in the best way The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present.

The present invention can be applied to any refrigerator including an actuator connected to a wire which is a conducting wire, in addition to the door driving. Hereinafter, the present invention will be described with reference to an example of a refrigerator having a bottom freeze type for convenience of explanation and understanding.

1 is a front view showing the appearance of a refrigerator according to the present invention, Figure 2 is a perspective view showing a self-drawing door is equipped with an automatic winding device of the present invention.

1 and 2, the refrigerator has an outer shape formed by a main body having a substantially rectangular parallelepiped shape, and a storage space for storing food is formed therein. The storage space of the refrigerator main body 1 is divided up and down so that a refrigerating chamber (unsigned) is formed in the upper portion, while a freezing chamber 2 is formed in the lower portion.

The opened front surface of the refrigerating chamber is shielded by a pair of left and right refrigerating chamber doors 3, and the open front surface of the freezing chamber 2 is shielded by one or a plurality of freezing chamber doors 4.

The refrigerating chamber door (3) is hinged to both sides of the refrigerator main body (1) is composed of a hinged door, the freezer door (4) is slidingly coupled to the refrigerator main body (1) is made of a drawer-type door. Here, the freezing chamber door 4 will be described in detail.

On the inner wall surface of the freezer compartment (2) is provided a rail assembly for withdrawing / entering the freezer compartment door (4) with the basket (5), the freezer door (4) on one side of the rail assembly is a basket (5) With the drive unit 10 is automatically installed to withdraw / withdraw.

The rail assembly is accommodated in a rail housing provided on the inner wall surface of the freezing compartment (2). The rail housings are provided on the left and right side walls of the freezing chamber 2, respectively, and extend from the front end to the rear end of the freezing chamber 2.

In addition, the rail housing may be fixed to the inner wall surface of the freezing compartment 2 by a coupling member such as a separate screw or to be coupled to a bracket (not shown) already mounted on the wall surface of the freezing compartment 2.

The rail assembly is configured such that a plurality of rails are sequentially stacked so as to slide while rolling by respective bearings (not shown) provided therein.

The drive unit 10 includes a drive motor and is engaged with the gear gear formed on the rail by the rotational operation of the drive motor so that the freezing chamber door 4 of the drawing type is automatically drawn out / retracted with the basket 5. do.

The drive motor provided in the drive unit 10 is composed of a bidirectional rotation motor that can selectively rotate in the forward and reverse direction. The rotating shaft of the driving motor is coupled to the driving shaft through an intermediate gear (not shown), and a wire 30, which is a lead wire for applying power to the driving motor, is received in a cable chain to electrically connect the driving motor to an external power source. And the cable chain is slidably coupled to the middle of the lower side of the rail.

Looking at the process of withdrawing / entering the freezer compartment door 10 in the refrigerator equipped with a safety device according to the present invention as follows.

That is, when the freezing chamber door 4 is pulled forward, the freezing chamber door 4 is pulled forward and the driving motor rotates in the opening direction. Then, the freezer door 4 is pulled out together with the basket 5 while the straight teeth formed on the rail and the teeth formed on the rotation shaft of the driving motor are engaged with each other to rotate in the opening direction. At the same time, since the rail assembly of the freezer compartment door 4 and the rail housing of the freezer compartment 2 are mutually coupled to each other, the rail assembly of the freezing compartment door 4 is slid to the front while gradually sliding relative movement to each other. Then, the freezing chamber door 4 is gradually opened, and the basket 5 is exposed to the outside as much as possible, so that food can be put or stored in the basket 5.

On the other hand, if the freezing chamber door 4 is pushed backward, the freezing chamber door 4 is pulled back to rotate the drive motor in the closing direction. Then, while the teeth of the rail and the teeth of the drive motor rotation shaft is engaged to rotate in the closing direction, the freezer compartment door 4 is introduced into the rear with the basket (5). At the same time, the rail assembly of the freezing compartment door 4 is overlapped while sliding in the opposite direction to the opening direction by the rail housing of the freezing compartment 2 so that the freezing compartment door 4 gradually closes, and the basket 5 is closed. It is completely inserted into the freezer compartment to refrigerated food stored in the basket (5).

When the freezer compartment door 4 moves forward and backward, the driving unit 10 moves together with the freezer compartment door 4. In this process, tension is applied to the wire 30 which is the lead wire, which may cause a problem such as the wire 30 is separated or separated from the driving unit 10. In order to prevent this, it is wrapped by a chain to protect the wire wire 30 is the lead wire.

In such a conventional automatic refrigerator take-out system, when the wire 30 connected to the drawer-type freezer door 4 is withdrawn or returned to its original state, the chain is retracted or stretched. In order to protect the existing refrigerator wire 30, the cost competitiveness is reduced by using a chain which is a separate structure, and waste of unnecessary space occurs in a section in which the chain operates.

Hereinafter, the wire breakage prevention and space optimization using the automatic winding apparatus of the present invention will be described with reference to FIGS. 3 and 4. Figure 3 is a perspective view showing a drawer-type door equipped with the automatic winding device of the present invention, Figure 4 is a detailed view showing a leaf spring inside the automatic winding device of the present invention.

2 and 3, the present invention is mounted inside the door of the refrigerator, the drive unit 10 for automatically opening and closing the door in the drawer method; A wire 30 which is a conductive wire for supplying electric power to the driving unit; And an automatic winding device 100, in which the wire 30 is unwound when the door is opened and the wire 30 is automatically wound when the door is closed, the automatic retracting device including the automatic winding device.

3 does not show a drive unit 10 for automatically drawing out the drawer type door of the present invention, but as shown in FIG. 2, the drive unit 10 is provided on one side of the freezer door 4, The gear unit is provided on the driving motor and the rotating shaft to engage with the teeth formed on the inner rail of the freezing chamber 2. In this case, the driving unit is formed to electrically connect the wire 30 to the rear of the automatic winding device 100 in FIG. 3.

In addition, since the conventional wire 30, the automatic winding device 100 is not provided, the wire 30 is protected in a form surrounded by a chain tube, and the drive unit 10 is integrated with the freezer door 4. Connected together and moved back and forth together.

Accordingly, when the door is closed, the drive unit 10 enters into the freezer compartment 2, and the chain tube including the wire 30 is wrinkled. On the contrary, when the door is opened, the driving unit 10 is drawn out to the freezing chamber 2 and the chain including the wire 30 is opened.

In other words, in the automatic take-out system of the refrigerator, when the wire connected to the drawer is pulled out or returned to its original state, a chain-type protection tube is included to prevent the wire from being twisted or broken so as to retract when the door is closed. When opened, it is expanded.

In this case, because a separate structure of the chain is used to protect the refrigerator wire, even though the wire is prevented from being broken or twisted, the cost competitiveness is reduced by the manufacture of the tube chain, and unnecessary space is provided in the section where the chain operates. It is inferior to convenience and economy.

3 and 4, the self-locking device 100 includes: a housing 110 in which wires 30 are pulled out, drawn out or wound; A leaf spring having an elastic restoring force in a rotational direction; And a winding shaft 120 in which one end of the leaf spring is fixed inside the housing 110.

In addition, the wire 30 is characterized in that the automatic winding by the elastic force of the leaf spring of the automatic winding device.

When the automatic winding device 100 of the wire of the present invention is used, the pull spring connected to the central axis while the wire 30 wound on the automatic winding device 100 is pulled out when the freezer door 4 is pulled open. The 130 is wound around the winding shaft 120 to generate an elastic stress. When the drawer-type door is pushed to close, the wire 30 is automatically wound and returned to its original position by the elastic stress of the leaf spring 130 acting on the wire 30.

Accordingly, since the wire 30 does not fold or retract, the occurrence of space occupied by the wire 30 can be minimized, and the wire 30 is wound in the winding device 100 without being folded or retracted. Since it is stored, it is possible to improve durability without causing problems such as twisting or cutting of the wire (wire, 30), and since the wire wire 30 is wound around the optimized volume in the winding device 100, the refrigerator The parts can be made compact.

4 and 5, the leaf spring 130 is configured to rotate the rotating plate 150 mounted to the inside of the housing 110 of the automatic winding device 100 by elastic stress. That is, one end of the leaf spring is fixed to the winding shaft 120, which is a rotational central axis of the rotating plate 150, and the other end is fixed at a position spaced a predetermined distance from the center of the rotating plate 150, the leaf spring 130 Rotational elastic stress of the) to act as a rotational stress moment of the rotating plate 150.

Hereinafter, with reference to the accompanying drawings, it will be described in detail with respect to the configuration and operation of the automatic winding device using the wire protection tube 300 of the present invention.

The present invention is mounted inside the door of the refrigerator, the drive unit 10 for automatically opening and closing the door in the drawer method; A wire 30 which is a conductive wire for supplying electric power to the driving unit; A protective tube 300 manufactured by insert injection and protected by wrapping the wire 30; When the door is opened, the wire 30 is released, the automatic winding device 100 is wound automatically when the wire 30 is closed; Automatic winding device using a wire protection tube comprising a Provides an automatic pullout door.

The automatic winding device 100, the housing 110, which is wire is drawn out, drawn out or wound as described above with reference to Figures 3 and 4; A leaf spring having an elastic restoring force in a rotational direction; A rotating plate 150 on which the leaf spring 130 is mounted and rotates so that the wire 30 is wound; And a winding shaft 120 to which one end of the leaf spring is fixed in the housing 110.

5 and 6, the protective tube 300 of the present invention may be formed by insert injection molding to protect the wire 30 and integrally with the wire 30. In addition, the protective tube 300 is formed to a certain thickness, even if the wire 30 is subjected to a large force by an external impact or tensile force, so that the protective tube 300 can support this to prevent breakage or breakage of the conductor Can be.

And, the rotating plate 150, as shown in Figure 5, the locking projection 153 to be wound and fixed to the wire protection tube 300; includes, the wire is protected by the protection tube 300 30 is drawn out hole 155 to the outer periphery of the rotating plate 150; is formed on the outer wall 152 of the rotating plate.

That is, the rotating plate 150 includes an inner wall 151 and an outer wall 152, the outlet hole 155 is formed in the outer wall 153, and the wire 30 is connected to the locking protrusion 153. It is wound up to be drawn out through the drawing hole 155.

The wire 30 for supplying power and transmitting a signal may be connected to a driving motor (not shown) in the housing 110 in which the rotating plate 150 is mounted. As a thin wire, the wire 30 may be twisted due to tension and rotation. It may break or break. Accordingly, in order to prevent the wire from being damaged due to tensile force or rotation of the rotating plate, the wire 30 is wrapped and protected by a protective tube 300 of a predetermined thickness.

At this time, the wire 30 wrapped by the protection tube 300 is to be wound or unwinded by the rotation of the rotary plate 150 itself, the wire formed to a certain thickness of the protection tube ( 300 is integrally formed with the wire 30 by insert injection.

Then, the wire 30 is wound on the inner wall 151 by the protective tube 300 as shown in Figure 6 and wound around the locking projection 153 through the outlet hole 155 formed in the outer wall 153 rotating plate 150 ) Will be drawn out. In this way, the wire 30 wound on the locking protrusion 153 is firmly fixed by the frictional force in the locking protrusion, and is broken even by the rotational operation of the rotating plate 150 for the winding or loosening operation by the strong durability of the protection tube 300. Loss or damage can be prevented in advance.

Looking at another embodiment of the present invention with reference to Figure 7, the protective tube 300, the folded cutout portion 310 is cut off one side on the cross-section of the protective tube to the wire 30 is folded; Accordingly, the folding cutout 310 may be formed in plural in the inner circumferential direction in which the wire 30 is wound by being spaced apart by a predetermined interval with the protection part 330 attached and protected by the wire therebetween.

The folding cutout 310 can be easily wound around the rotating plate 150 by being cut in the inner direction in which the wire 30 is wound, and also smoothly unwound for the loosening operation. It is possible to prevent twisting or damage in advance.

Accordingly, the present invention includes the protective tube 300 includes a folding cutout portion 310 in which one side of the protective tube is cut in the cross-section of the wire 30, and is wound around the automatic winding device of the wire when the door is closed. When the door is opened, it is unwound to provide a wire to be drawn out.

Thus, the folding cutout 310, a plurality of wires formed at a predetermined interval in the inner circumferential direction in which the wire is wound so that the wire integrated with the insert injection protection tube can be easily wound on the winding device.

According to another embodiment of the present invention, the present invention is a refrigerator body (1) having a refrigerator compartment and a freezer compartment as shown in Figure 1; A refrigerator compartment door 3 for opening and closing the refrigerator compartment; A freezing chamber door (4) formed at a lower portion of the refrigerator body (1) and opened and closed by a drawer type; A driving unit 10 mounted inside the freezing chamber door 4 to automatically open and close the freezing chamber door 4 in a drawer manner; A wire 30 which is a conductive wire for supplying power to the driving unit 10; A protective tube 300 manufactured by insert injection and protected by wrapping the wire; And an automatic winding device 100, in which the wire is unwound when the door is opened and the wire is automatically wound when the door is closed.

Accordingly, the protective tube 300 is formed in a shape in which one side is cut in cross section, and a plurality of folding cutouts 310 are formed at a predetermined interval in the inner circumferential direction around which the wire is wound.

The above-described embodiment is a person having ordinary knowledge in the technical field to which the present invention belongs (hereinafter referred to as the person skilled in the art) is equipped with a self-winding device equipped with an automatic winding device using a wire protection tube according to the present invention and The present invention is not limited to the above-described embodiment and the accompanying drawings, which are only preferred embodiments for easily implementing the refrigerator. Therefore, the scope of the present invention is not limited thereto. It will be apparent to those skilled in the art that various changes, substitutions, and alterations can be made hereto without departing from the spirit of the present invention, and it is obvious that those parts easily changeable by those skilled in the art are also included in the scope of the present invention.

1: refrigerator body 3: refrigerator door
4: freezer door 5: basket
10: drive unit 30: wire (wire)
100: automatic winding device 110: housing
120: winding axis 130: leaf spring
150: rotating plate 151: inner wall
152: outer wall 153: protrusion
155: withdrawal hole 300: protective tube
310: folded incision 330: protection

Claims

A driving unit mounted inside the door of the refrigerator and automatically opening and closing the door in a drawer manner;
A wire that is a conductive wire for supplying power to the drive unit;
A protective tube made by insert injection and protected by wrapping the wire; And
When the door is opened, the wire is released, the automatic winding device that the wire is automatically wound when closed; Auto-retractable door equipped with an automatic winding device using a wire protection tube, characterized in that it comprises a.

The method of claim 1,
The automatic winding device,
A housing in which the wire is pulled out, or wound;
A leaf spring having an elastic restoring force in a rotational direction;
A rotating plate to which the leaf spring is mounted and rotates so that the wire is wound; And
Automatic winding device equipped with an automatic winding device using a wire protection tube, characterized in that it comprises a; winding shaft is fixed to one end of the leaf spring inside the housing.

3. The method of claim 2,
The rotating plate,
Automatic wire-retracting door equipped with an automatic winding device using a wire protection tube, characterized in that it comprises a; and the locking projection is wound around the wire protection tube.

The method of claim 3, wherein
The rotating plate,
Auto-retractable door equipped with a self-winding device using a wire protection tube, characterized in that it comprises; outgoing hole that the wire protected by the protective tube is drawn out to the outer circumference of the rotating plate.

The method of claim 4, wherein
The rotating plate,
Including an inner wall and an outer wall, the drawing hole is formed in the outer wall,
The automatic retractable door equipped with an automatic winding device using a wire protection tube, characterized in that the wire is wound on the locking projections and drawn out through the drawing hole.

The method of claim 1,
The protective tube,
Auto-retractable door equipped with a self-winding device using a wire protection tube, characterized in that it comprises a; folding section cut one side on the cross section of the protective tube to the wire folding portion.

The method according to claim 6,
The folding incision,
Auto-retractable door equipped with an automatic winding device using a wire protection tube, characterized in that a plurality of wires are formed at predetermined intervals in the inner circumferential direction of the winding.

A refrigerator body having a refrigerator compartment and a freezer compartment therein;
A refrigerator compartment door to open and close the refrigerator compartment;
A freezing chamber door formed at a lower portion of the refrigerator body and opened and closed by a drawer type;
A driving unit mounted inside the freezing compartment door and automatically opening and closing the freezing compartment door in a drawer manner;
A wire that is a conductive wire for supplying power to the drive unit;
A protective tube made by insert injection and protected by wrapping the wire; And
And an automatic winding device in which the wire is unwound when the door is opened and the wire is automatically wound when the door is closed.

The method of claim 9,
The protective tube,
It is formed in a shape in which one side is cut in the cross-section, the plurality of folding cut-off portion is formed in a predetermined interval in the inner circumferential direction winding the wire; refrigerator comprising a.

A wire that is a lead for supplying power; And a protective tube formed by insert injection to wrap and protect the wire.
A folding cut-out portion of which one side is cut on the cross section of the protective tube in a portion where the wire is folded in the protective tube; is formed, the wire wrapped by the protective tube is built-in retracted, or the wire is automatically unwinding wire unwinding device.

11. The method of claim 10,
The folding incision,
A wire self-winding device comprising a protective tube, characterized in that the plurality of wires are formed at a predetermined interval in the inner circumferential direction.