Heat rod assembly

Abstract

The present invention relates to a heat rod assembly comprising a PTC frame having a plurality of installation holes formed spaced apart from each other in the longitudinal direction, a PTC element accommodated in each of the installation holes of the PTC frame with the upper and lower surfaces thereof, which face each other, being exposed, first and second terminal plates installed to be respectively in contact with both surfaces of the PTC element, a tubular housing formed of a metal material and accommodating the first and second terminal plates, the PTC elements, and the PTC frame therein, and an elastic insulating pad interposed between the first and second terminal plates and the upper and lower inner surfaces of the housing. Accordingly, in the actual manufacturing process, the first and second terminal plates, the PTC element, and the PTC frame are assembled and inserted from one end thereof into the hollow portions of the tubular housing and are finished by pressing while placed in the frame, and thus, through residual stress due to plastic deformation of the housing, a tight fit of the internal components is maintained and robust coupling is established.

Description

Heat rod assembly

[0001] The present invention relates to a heat rod assembly, and more particularly, to a heat rod assembly including a PTC element, which significantly improves adhesion by increasing residual stress during vertical plastic deformation by pressing, and prevents the relative positions of components from being misaligned even when pressing is performed.

[0002] Typically, vehicles are equipped with a heating system to heat the interior or to dehumidify or defrost the windshield.

[0003] Since these heating devices have coolant flowing around the engine after the engine is running, it takes a relatively long time for the coolant to heat up and heat the interior.

[0004] Accordingly, heat rod assemblies with built-in PCT elements, etc., have been adopted for over a decade to enable rapid heating after starting.

[0005] In addition, electric vehicles of various structures are being manufactured recently, and since the electric vehicles do not have a separate engine and a coolant configuration heated by the engine, heat rod assemblies for vehicle heaters with built-in PCT elements are being adopted in large numbers.

[0006] Hereinafter, a representative example of a heat rod assembly for a vehicle heater according to the prior art document described below will be described with reference to FIGS. 1 and 2.

[0007] As shown, a heat rod assembly for a vehicle heater according to the prior art is composed of a (+) terminal plate (50) and a (-) terminal plate (52), a PTC element (40) interposed therebetween, a PTC frame (30) accommodating the PTC element (40), a tubular housing (10) accommodating the (+), (-) terminal plates (50, 52), the PTC element (40) and the PTC frame (30) and including a conductor, and an insulating film (20) interposed between the (+), (-) terminal plates (50, 52) and the housing (10).

[0008] However, according to the conventional heat rod assembly of this configuration, since it was manufactured by simply inserting the (+) terminal plate (50), (-) terminal plate (52), PTC element (40), PTC frame (30) and insulating film (20) into a tubular housing (10) in an assembled state, there was a disadvantage in that when manufacturing errors of individual parts accumulated, the sealing was greatly reduced during assembly and the desired performance was not exhibited.

[0009] [Prior Art Literature]

[0010] Korean Patent Publication No. 1096286 (December 13, 2011)

[0011] The present invention has been devised to solve the problems of the prior art described above, and the purpose of the present invention is to provide a heat rod assembly including a PTC element, in which adhesion is greatly improved by increasing residual stress during vertical plastic deformation by pressing, and in which the relative positions of components are not misaligned even when pressing is performed.

[0012] In order to achieve the above-mentioned purpose, the heat rod assembly according to the present invention,

[0013] A PTC frame in which a plurality of installation holes are formed spaced apart along the length;

[0014] A PTC element accommodated in each installation hole of the PTC frame with the upper and lower opposite sides exposed;

[0015] First and second terminal plates respectively installed in contact with both sides of the PTC element;

[0016] A tubular housing made of metal that houses the first and second terminal plates, the PTC element, and the PTC frame therein; and

[0017] Elastic insulating pads respectively interposed between the first and second terminal plates and the upper and lower inner surfaces of the housing;

[0018] It is characterized in that it is manufactured by assembling the first and second terminal plates, the PTC element and the PTC frame, inserting them from one end into the hollow of the housing, and pressing them in the up and down direction to cause plastic deformation.

[0019]

[0020] The above elastic insulating pad is characterized by comprising an elastic layer each placed in contact with the upper and lower inner surfaces of the housing, and an insulating layer each interposed between the elastic layer and the first and second terminal plates.

[0021]

[0022] The above elastic layer is characterized in that it is made of a silicone material or a silicone material including a mesh, and the above insulating layer is characterized in that it is made of a polyimide material.

[0023]

[0024] The cross-sectional shape of the above housing is characterized by being formed as a polygon with protruding sides.

[0025]

[0026] The above elastic insulating pad is characterized in that it is formed to extend so as to be interposed on the upper and lower inner surfaces of the housing and the upper and lower surfaces on both sides of the PTC frame.

[0027]

[0028] A first connecting portion protruding from one end of the PTC frame is formed at one longitudinal end of the first terminal plate, and a first engaging bend portion bent upward toward the bottom of the PTC frame is formed at the other longitudinal end, and a first engaging hole into which the first engaging bend portion is inserted is formed at the lower end of the PTC frame.

[0029] The second terminal plate is characterized in that a second connecting portion protruding from one end of the PTC frame is formed at one end in the longitudinal direction, a second hooking bend portion bent downward toward the top of the PTC frame is formed at the other end, and a second hooking hole is formed on the upper surface of the PTC frame, which is spaced apart from the first hooking hole in the width direction of the PTC frame and into which the second hooking bend portion is inserted.

[0030]

[0031] The PTC frame is characterized in that a first fitting groove and a second fitting groove are formed on the lower and upper sides to accommodate the first terminal plate and the second terminal plate, and the first terminal plate and the second terminal plate are arranged on the same plane as the lower and upper surfaces of the PTC frame adjacent to the first terminal plate and the second terminal plate, respectively.

[0032]

[0033] The PTC frame is characterized in that a first fitting hole and a second fitting hole are formed on one longitudinal end surface thereof to communicate with the first fitting groove and the second fitting groove, respectively, so that the first terminal plate and the second terminal plate are inserted into the first fitting groove and the second fitting groove, respectively, and the first connecting portion and the second connecting portion are fitted into the first fitting hole and the second fitting hole, respectively.

[0034]

[0035] The first connecting portion and the second connecting portion are formed so that a first through hole and a second through hole pass through them, and the bottoms of the first and second alignment grooves are formed so that a first insertion protrusion and a second insertion protrusion are protruded to be inserted into the first through hole and the second through hole, respectively.

[0036]

[0037] The first catch bending portion includes a first catch protrusion protruding toward the PTC frame at one point in the width direction, the second catch bending portion includes a second catch protrusion protruding toward the PTC frame at one point in the width direction, and a first insertion groove and a second insertion groove into which the first catch protrusion and the second catch protrusion are inserted are formed on one side of the first catch hole and the second catch hole, respectively.

[0038] According to the present invention having the configuration described above, the present invention comprises a PTC frame in which a plurality of installation holes are formed spaced apart along the longitudinal direction, a PTC element accommodated in each of the installation holes of the PTC frame with the upper and lower opposite sides exposed, first and second terminal plates respectively installed in contact with both sides of the PTC element, a tubular housing made of a metal material that accommodates the first and second terminal plates, the PTC element, and the PTC frame therein, and an elastic insulating pad respectively interposed between the first and second terminal plates and the upper and lower inner surfaces of the housing, so that in an actual manufacturing process, the first and second terminal plates, the PTC element, and the PTC frame are assembled and inserted from one end into the hollow portion of the tubular housing, and are finished by pressing while placed on a frame, so that a close relationship with internal components is maintained through residual stress due to plastic deformation of the housing, and a joint without shaking is achieved.

[0039] In addition, according to the present invention, the elastic insulating pad is composed of an elastic layer which is placed in contact with the upper and lower inner surfaces of the housing, and an insulating layer which is interposed between the elastic layer and the first and second terminal plates, so that the residual stress is further increased when plastically deformed by pressing due to the elastic layer, thereby achieving the effect of significantly improving the adhesion between components.

[0040] In addition, according to the present invention, the elastic layer may be made of a silicone material, and when made of a silicone material including a mesh made of glass fiber or the like, the elastic layer can maintain its shape, increase its tensile strength, and exhibit a tear-prevention function.

[0041] In addition, according to the present invention, the cross-sectional shape of the housing is configured as a hexagon with both sides protruding, and the hexagon is deformed while maintaining the cross-sectional shape in response to a pressing force, thereby preventing the occurrence of defects. In addition, since the upper and lower surfaces of the housing are naturally deformed relatively largely in the direction of narrowing, a large residual stress is generated due to the repulsive force of the elastic layer, and the effect of further increasing the adhesion between components can be obtained.

[0042] In addition, according to the present invention, the elastic insulating pad is formed to extend so as to be interposed on the upper and lower inner surfaces of the housing and the upper and lower surfaces of both sides of the PTC frame, thereby making it possible to further enhance the elastic repulsive force and residual stress by the elastic layer.

[0043] In addition, according to the present invention, a first connecting portion protruding from one end of the PTC frame is formed at one longitudinal end of the first terminal plate, and a first engaging bend portion bent upward toward the lower end of the PTC frame is formed at the other longitudinal end of the first terminal plate, a first engaging hole into which the first engaging bend portion is inserted is formed on the lower surface of the PTC frame, a second connecting portion protruding from one end of the PTC frame is formed at one longitudinal end of the second terminal plate, and a second engaging bend portion bent downward toward the upper end of the PTC frame is formed at the other end, and a second engaging hole into which the second engaging bend portion is inserted is formed on the upper surface of the PTC frame, and is spaced apart from the first engaging hole in the width direction of the PTC frame, so that the first terminal plate and the second terminal plate are inserted into the hollow of the housing without shaking while being fitted into the PTC frame with the PTC element therebetween, so that the relative positions can be maintained without being misaligned even after plastic processing.

[0044] In addition, according to the present invention, a first fitting groove and a second fitting groove for receiving the first terminal plate and the second terminal plate are formed on the lower and upper portions of the PTC frame, and the lower surface of the first terminal plate and the upper surface of the second terminal plate are arranged on the same plane as the lower surface and the upper surface of the PTC frame adjacent to the first terminal plate and the second terminal plate, respectively, so that the first terminal plate and the second terminal plate do not have relative horizontal shaking with respect to the PTC frame and can be prevented from coming off as much as possible.

[0045] In addition, according to the present invention, a first fitting hole and a second fitting hole are formed on one longitudinal end surface of the PTC frame so as to communicate with the first fitting groove and the second fitting groove, respectively, so that the first terminal plate and the second terminal plate are inserted into the first fitting groove and the second fitting groove, respectively, and the first connecting portion and the second connecting portion are inserted into the first fitting hole and the second fitting hole, respectively, so that a firm connection of the PTC frame, the PTC element, the first terminal plate, and the second terminal plate is formed before being inserted into the tubular housing, so that the relative positions can be reliably prevented from being misaligned or detached during the process of being inserted into the housing or during plastic deformation by pressing.

[0046] In addition, according to the present invention, a first through hole and a second through hole are formed to penetrate the first connecting portion and the second connecting portion, and a first insertion protrusion and a second insertion protrusion, which are inserted into the first through hole and the second through hole, are formed to protrude at the bottoms of the first and second alignment grooves, so as to completely block horizontal shaking and separation between the first terminal plate and the second terminal plate and the PTC frame.

[0047] In addition, according to the present invention, the first engaging bend includes a first engaging projection that protrudes toward the PTC frame at one point in the width direction, the second engaging bend includes a second engaging projection that protrudes toward the PTC frame at one point in the width direction, and a first insertion groove and a second insertion groove into which the first engaging projection and the second engaging projection are inserted are formed on one side of the first engaging hole and the second engaging hole, so that there is an effect of being able to reliably prevent lateral relative movement when mutually coupled.

[0048] Fig. 1 is a perspective view showing the configuration of a heat rod assembly according to the prior art.

[0049] Figure 2 is an exploded perspective view showing the configuration of a heat rod assembly according to the prior art.

[0050] Figure 3 is a perspective view showing the configuration of a heat rod assembly according to the present invention.

[0051] Figure 4 is an exploded perspective view showing the configuration of a heat rod assembly according to the present invention.

[0052] FIG. 5 is a cross-sectional view taken along AA of FIG. 3 showing the configuration of a heat rod assembly according to the present invention.

[0053] Figure 6 is an exploded perspective view of one end of a heat rod assembly according to the present invention, (a) is a top perspective view, and (b) is a bottom perspective view.

[0054] Fig. 7 is an exploded perspective view of the other end of the heat rod assembly according to the present invention, (a) is a top perspective view, and (b) is a bottom perspective view.

[0055] FIG. 8 is a drawing showing an example of a manufacturing process of a heat rod assembly according to the present invention in sequence.

[0056] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0057] As illustrated in FIGS. 3 to 7, a heat rod assembly (1000) according to the present invention comprises a PTC frame (100) in which a plurality of installation holes (195) are formed spaced apart from each other along the longitudinal direction, a PTC element (200) accommodated in each installation hole (195) of the PTC frame (100) with its upper and lower opposite surfaces exposed, first and second terminal plates (310, 320) respectively installed in contact with both surfaces of the PTC element (200), a metal tubular housing (400) that accommodates the first and second terminal plates (310, 320), the PTC element (200) and the PTC frame (100) therein, and elastic insulating pads (500) respectively interposed between the first and second terminal plates (310, 320) and the upper and lower inner surfaces of the housing (400).

[0058] The above housing (400) may be made of a metal with excellent thermal conductivity, such as aluminum, and the PTC frame (100) may be made of non-conductive plastic.

[0059] In particular, the housing (400) may have a tube shape manufactured through extrusion or other known manufacturing methods.

[0060]

[0061] Accordingly, in the actual manufacturing process, as shown in Fig. 8, the first and second terminal plates (310, 320), the PTC element (200), and the PTC frame (100) are inserted into the hollow portion of the housing (400) from one end in an assembled state, and are finished by pressing while placed in the frame.

[0062] In this case, the tubular housing (400) maintains a close relationship with the internal components through residual stress due to plastic deformation, and a stable connection is achieved.

[0063] As illustrated in FIG. 5, the elastic insulating pad (500) is composed of an elastic layer (510) that is placed in contact with the upper and lower inner surfaces of the housing (400), and an insulating layer (520) that is interposed between the elastic layer (510) and the first and second terminal plates (310, 320), and the elastic layer (510) and the insulating layer (520) may be formed in a laminated configuration.

[0064] Due to the elastic layer (510) above, the residual stress is further increased when plastic deformation is caused by pressing, thereby significantly improving the adhesion between components.

[0065] The above elastic layer (510) is preferably composed of silicone or the like, which has excellent heat transfer capability, can elastically maintain its shape, and minimizes noise transmission.

[0066] In addition, it is preferable that the insulating layer (520) be composed of polyimide or the like to maintain a high insulation resistance.

[0067] It is preferable that the elastic layer (510) be configured to include a mesh (not shown) made of glass fiber material or the like, thereby maintaining the shape of the elastic layer (510) and increasing the tensile strength, while also having a tear-prevention function.

[0068] Meanwhile, it is preferable that the cross-sectional shape of the housing (400) be configured as a hexagon with both sides protruding.

[0069] Since the heat rod assembly (1000) according to the present invention is manufactured through a process of plastic deformation by pressing, if the housing (400) has a rectangular cross-sectional shape as in the past, the side of the housing (400) is partially crushed or deformed into an irregular shape during plastic deformation, resulting in defective products, but if it has a hexagonal cross-sectional shape, the hexagon is deformed while maintaining the cross-sectional shape in response to the pressing force without such a phenomenon, thereby preventing the occurrence of defective products.

[0070] In the drawing, the cross-sectional shape of the housing (400) is a hexagon with both sides protruding, but it may have a polygonal shape such as an octagon or decagon with both sides protruding.

[0071] In addition, since the upper and lower surfaces of the housing (400) are naturally deformed relatively significantly in the direction of narrowing in response to the pressing force after the upper and lower plastic deformation by pressing, a large residual stress is generated due to the repulsive force of the elastic layer (510), and the effect of further increasing the adhesion between components can be obtained.

[0072] In addition, it is preferable that the elastic insulating pad (500) be formed to extend so as to be interposed between the upper and lower inner surfaces of the housing (400) and the upper and lower surfaces of both sides of the PTC frame (100), thereby further enhancing the elastic repulsive force and residual stress by the elastic layer (510).

[0073] Meanwhile, as shown in FIGS. 6 and 7, a first connecting portion (311) protruding from one end of the PTC frame (100) is formed at one end of the longitudinal direction of the first terminal plate (310), and a first hooking bend portion (312) bent upward toward the lower end of the PTC frame (100) is formed at the other end, and a first hooking hole (110) into which the first hooking bend portion (312) is inserted is preferably formed at the lower surface of the PTC frame (100).

[0074] In addition, it is preferable that a second connecting portion (321) protruding from one end of the PTC frame (100) is formed at one end in the longitudinal direction of the second terminal plate (320), and a second hooking bend portion (322) bent downward toward the top of the PTC frame (100) is formed at the other end, and a second hooking hole (120) is formed on the upper surface of the PTC frame (100) so as to be spaced apart from the first hooking hole (110) in the width direction of the PTC frame (100) and into which the second hooking bend portion (322) is inserted.

[0075] According to this configuration, the first terminal plate (310) and the second terminal plate (320) are inserted into the hollow of the housing (400) without shaking while being fitted into the PTC frame (100) with the PTC element (200) in between, so that the relative positions can be maintained without being misaligned even after plastic processing.

[0076] In this way, the first terminal plate (310) and the second terminal plate (320) are arranged in contact with the lower and upper surfaces of the PTC frame (100), respectively, and the first connecting portion (311) and the second connecting portion (321) are arranged on one end in the longitudinal direction, and the first engaging bend portion (312) and the second engaging bend portion (322) are arranged on the other end in the longitudinal direction.

[0077] The first connecting portion (311) and the second connecting portion (321), and the first engaging bend portion (312) and the second engaging bend portion (322) have a width smaller than the widths of the first terminal plate (310) and the second terminal plate (320), and the first connecting portion (311) and the second connecting portion (321), and the first engaging bend portion (312) and the second engaging bend portion (322) are arranged to be spaced apart from each other in the width direction.

[0078] It is preferable that a first fitting groove (130) and a second fitting groove (140) into which the first terminal plate (310) and the second terminal plate (320) are inserted are formed at the lower and upper portions of the PTC frame (100), so that the lower surface of the first terminal plate (310) and the upper surface of the second terminal plate (320) are arranged on the same plane as the lower surface and the upper surface of the PTC frame (100) adjacent to the first terminal plate (310) and the second terminal plate (320), respectively, so as to prevent relative horizontal shaking and to prevent detachment as much as possible.

[0079] In addition, a first fitting hole (150) and a second fitting hole (160) are formed on one longitudinal side of the PTC frame (100) to communicate with the first fitting groove (130) and the second fitting groove (140), respectively, so that the first terminal plate (310) and the second terminal plate (320) can be inserted into the first fitting groove (130) and the second fitting groove (140), respectively, and the first connecting portion (311) and the second connecting portion (321) can be inserted into the first fitting hole (150) and the second fitting hole (160), respectively.

[0080] According to this configuration, along the longitudinal direction of the first terminal plate (310) and the second terminal plate (320), at one end, the first connecting portion (311) and the second connecting portion (321) are respectively fitted into the first fitting hole (150) and the second fitting hole (160), and at the other end, the first engaging bend (312) and the second engaging bend (322) are respectively coupled to the first engaging hole (110) and the second engaging hole (120), so that before being inserted into the tubular housing (400), the PTC frame (100), the PTC element (200), the first terminal plate (310), and the second terminal plate (320) are firmly coupled, thereby reliably preventing the relative positions from being misaligned or detached during the process of being inserted into the housing (400) or during plastic deformation by pressing.

[0081] In addition, a first through hole (315) and a second through hole (325) are formed in the first connecting portion (311) and the second connecting portion (321), and a first insertion protrusion (191) and a second insertion protrusion (192) are formed on the bottom of the first alignment groove (130) and the second alignment groove (140) to be inserted into the first through hole (315) and the second through hole (325), respectively, so that horizontal shaking and separation between the first terminal plate (310) and the second terminal plate (320) and the PTC frame (100) can be completely prevented.

[0082] In addition, the first catch bend (312) includes a first catch protrusion (313) protruding toward the PTC frame (100) at a point in the width direction (preferably the center), and the second catch bend (322) includes a second catch protrusion (323) protruding toward the PTC frame (100) at a point in the width direction, and a first insertion groove (170) and a second insertion groove (180) into which the first catch protrusion (313) and the second catch protrusion (323) are inserted are formed on one side of the first catch hole (110) and the second catch hole (120), respectively, so that lateral relative movement can be reliably prevented when they are coupled together.

[0083] It is preferable that the first hanging hole (110) and the second hanging hole (120) are formed at the bottom of the first alignment groove (130) and the second alignment groove (140), respectively.

[0084] In addition, it is preferable that a catch (199) having a cross-sectional area larger than the cross-sectional area of ​​the middle portion is formed at both longitudinal ends or at least one end of the PTC frame (100) to prevent the housing (400) from being separated in the longitudinal direction after plastic deformation by pressing.

[0085] Meanwhile, FIG. 8 illustrates in detail an example of a manufacturing process of a heat rod assembly (1000) according to the present invention.

[0086]

[0087] The embodiments of the present invention are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible within the scope of the following claims.

Claims

1. A PTC frame in which a plurality of installation holes are formed spaced apart along the longitudinal direction; A PTC element accommodated in each installation hole of the PTC frame with the upper and lower opposite sides exposed; First and second terminal plates respectively installed in contact with both sides of the PTC element; A tubular housing made of metal that houses the first and second terminal plates, the PTC element, and the PTC frame therein; and Elastic insulating pads respectively interposed between the first and second terminal plates and the upper and lower inner surfaces of the housing; Consists of, including, A heat rod assembly characterized in that the first and second terminal plates, the PTC element, and the PTC frame are assembled, inserted into the hollow portion of the housing from one end, and then pressed in an up-and-down direction to be manufactured through plastic deformation.

2. In paragraph 1, A heat rod assembly characterized in that the elastic insulating pad is composed of an elastic layer each placed in contact with the upper and lower inner surfaces of the housing, and an insulating layer each interposed between the elastic layer and the first and second terminal plates.

3. In paragraph 2, A heat rod assembly characterized in that the elastic layer is made of a silicone material or a silicone material including a mesh, and the insulating layer is made of a polyimide material.

4. In any one of paragraphs 1 to 3, A heat rod assembly characterized in that the cross-sectional shape of the housing is formed as a polygon with protruding sides.

5. In paragraph 4, A heat rod assembly characterized in that the elastic insulating pad is formed to extend so as to be interposed on the upper and lower inner surfaces of the housing and the upper and lower surfaces of both sides of the PTC frame, respectively.

6. In any one of paragraphs 1 to 3, A first connecting portion protruding from one end of the PTC frame is formed at one longitudinal end of the first terminal plate, and a first engaging bend portion bent upward toward the bottom of the PTC frame is formed at the other longitudinal end, and a first engaging hole into which the first engaging bend portion is inserted is formed on the lower surface of the PTC frame. A heat rod assembly characterized in that a second connecting portion protruding from one end of the PTC frame is formed at one end of the longitudinal direction of the second terminal plate, a second engaging bend portion bent downward toward the top of the PTC frame is formed at the other end, and a second engaging hole into which the second engaging bend portion is inserted is formed on the upper surface of the PTC frame and is spaced apart from the first engaging hole in the width direction of the PTC frame.

7. In paragraph 6, A heat rod assembly characterized in that a first fitting groove and a second fitting groove are formed on the lower and upper portions of the PTC frame to accommodate the first terminal plate and the second terminal plate, and the lower surface of the first terminal plate and the upper surface of the second terminal plate are arranged on the same plane as the lower surface and the upper surface of the PTC frame adjacent to the first terminal plate and the second terminal plate, respectively.

8. In paragraph 7, A heat rod assembly characterized in that a first fitting hole and a second fitting hole are formed on one longitudinal end surface of the PTC frame to communicate with the first fitting groove and the second fitting groove, respectively, so that the first terminal plate and the second terminal plate are inserted into the first fitting groove and the second fitting groove, respectively, and the first connecting portion and the second connecting portion are inserted into the first fitting hole and the second fitting hole, respectively.

9. In paragraph 8, A heat rod assembly characterized in that a first through hole and a second through hole are formed to penetrate the first connecting portion and the second connecting portion, and a first insertion protrusion and a second insertion protrusion, which are inserted into the first through hole and the second through hole, are formed to protrude on the bottom of the first and second alignment grooves, respectively.

10. In paragraph 6, A heat rod assembly characterized in that the first engaging bending portion includes a first engaging projection portion protruding toward the PTC frame at one point in the width direction, the second engaging bending portion includes a second engaging projection portion protruding toward the PTC frame at one point in the width direction, and a first insertion groove and a second insertion groove into which the first engaging projection portion and the second engaging projection portion are inserted are formed on one side of the first engaging hole and the second engaging hole, respectively.

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