WO2008056949A1

WO2008056949A1 - Ptc heater

Info

Publication number: WO2008056949A1
Application number: PCT/KR2007/005620
Authority: WO
Inventors: Tae Soo Sung
Original assignee: Modine Korea, Llc.
Priority date: 2006-11-09
Filing date: 2007-11-08
Publication date: 2008-05-15
Also published as: DE112007002642T5; CN101222795A; CN101222795B; KR100720129B1

Abstract

A PTC heater is disclosed. The PTC heater of the present invention includes radiation fins (300), and a PTC rod (100), which has therein upper and lower junction surfaces (122), each of which is in close contact with one side of the corresponding radiation fin. Fin guide protrusions (110) are integrally provided on respective opposite edges of each of the junction surfaces. The PTC heater further includes frame bars (500), which couple the PTC rod and the radiation fins to each other. Each frame bars has a bent part (525), which is convex towards the radiation fins. The PTC heater further includes housings (600) and (700), which are provided on respective longitudinal opposite ends of the frame bars. Each radiation fin is directly fitted between the corresponding fin guide protrusions. The frame bars keep the radiation fins in close contact with the PTC rod using the elastic force of the bent parts thereof.

Description

[DESCRIPTION]

[invention Title] PTC HEATER

[Technical Field] The present invention relates, in general, to PTC

(positive temperature coefficient) heaters and, more particularly, to a PTC heater which includes a PTC rod, which is integrally provided with fin guide protrusions when the PTC rod is manufactured of an extruded tube, in order to make it possible to directly couple radiation fins to the PTC rod without using separate fin guides, and frame bars, which have bent structures to increase the contact force between the radiation fins and the PTC rod.

[Background Art] FIG. 1 is an exploded perspective view of a conventional PTC heater. FIG. 2 is an assembled sectional view of a radiation fin and a PTC rod of FIG. 1. FIG. 3 is an assembled sectional view of a radiation fin and a PTC rod according to a modification of FIG. 1. As shown in FIG. 1, the conventional PTC heater 1 includes at least two PTC rods 30, radiation fin assemblies 10, which are oriented parallel to the PTC rods 30, and housings 70, which are coupled to respective longitudinal opposite ends of the radiation fin assemblies 10.

Furthermore, each PTC rod 30 has therein a PTC element 60, which includes PTC terminals 61, which are disposed at positions spaced apart from each other at regular intervals, a terminal plate 50, which has a connection part 51, and on which the PTC element 60 is seated, and an insulating member 40, which is provided under the terminal plate 50.

The PTC heater 1 is manufactured by bringing the PTC rods 30 and the radiation fin assemblies 10 into close contact with each other and by coupling the housings 70 thereto.

The assembly structure between the PTC rod 30 and the radiation fin assemblies 10 will be described herein below with reference to FIG. 2.

The PTC rod 30 is manufactured by extruding aluminum material into a tube shape. An internal space 32 is defined in the PTC rod, and protrusions 31 are provided on the PTC rod. Each radiation fin assembly 10 has fin guides 12 on respective upper and lower ends thereof. Each fin guide 12 is inserted between the corresponding protrusions 31 in a sliding manner when the radiation fin assembly 10 is coupled to the PTC rod 30. Furthermore, in the case of FIG. 3, a PTC rod 35 has no internal space 32, unlike the case of FIG. 2. Therefore, in the case of FIG. 3, a PTC terminal 65 is disposed in a space defined between two PTC rod bodies of the PTC rod 35, which are spaced apart from each other by a predetermined distance, and is directly attached to the PTC rod 35. Each fin guide 22 of a radiation fin assembly 15 is inserted between corresponding protrusions 37 provided on the PTC rod 35.

However, the above-mentioned methods of coupling the PTC rod and the radiation fin assemblies to each other have the following problems.

In the case of the method of FIG. 2, because the separate fin guides 12 are required in each radiation fin assembly 10, the manufacturing costs are increased. In addition, because each fin guide 12 must be inserted between the corresponding protrusions 31 in a sliding manner, the manufacturing process is slow, compared to that of a method of assembling them in a perpendicular direction.

In the method of FIG. 3, in which the PTC terminal 65 is directly attached to the PTC rod 35, because a separate bonding process must be conducted, the manufacturing process is complicated, compared to the method using the extruded tube. As well, like the method of FIG. 2, there is a disadvantage in that separate fin guides 22 must be used. Furthermore, the PTC heater 1 of FIG. 1, which is manufactured by the method of FIG. 2 or FIG. 3, has no means for increasing contact force between the PTC rods 30 and the radiation fin assemblies 10 when they are coupled to each other. Thus, there is a problem in that, after the PTC heater 1 has been completely manufactured, the PTC rods 30 and the radiation fin assemblies 10 may undesirably become disassembled from each other.

[Disclosure] [Technical Problem]

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a

PTC heater which includes a PTC rod that does not require a separate fin guide, and frame bars which provide a structure for increasing the coupling force between the elements of the PTC heater, and to provide a PTC rod for use in the PTC heater.

[Technical Solution]

In order to accomplish the above object, in an aspect, the present invention provides a PTC heater, including a PTC rod made of an extruded tube, the PTC heater comprising: a plurality of radiation fins; a PTC rod having therein upper and lower junction surfaces, each of which has a planar shape and is in close contact with one side of the corresponding radiation fin, with fin guide protrusions integrally provided on respective opposite edges of each of the junction surfaces; a plurality of frame bars coupling the PTC rod and the radiation fins to each other, each of the frame bars having a first bent part, formed by curving an intermediate portion of the frame bar to have a shape that is convex towards the radiation fins; and a plurality of housings provided on respective longitudinal opposite ends of the frame bars, wherein each of the radiation fins is directly fitted between the corresponding fin guide protrusion, the frame bars bring the radiation fins into close contact with the PTC rod using a force generated by stretching the first bent parts, and the housings hold the frame bars.

The PTC heater may further comprise a radiation plate interposed between each of the frame bars and the corresponding radiation fin, which is in surface contact with the frame bar. Furthermore, an insulating plate, an electrode terminal, a PTC unit and a PTC element may be stacked on each other in positional sequence from a bottom to a top in an internal space defined in the PTC rod, wherein the insulating plate, the electrode terminal, the PTC unit and the PTC element are brought into close contact with an inner surface of the internal space of the PTC rod by applying pressure to the upper and lower junction surfaces.

In addition, each of the fin guide protrusions may have a convex rounded edge. Alternatively, an edge of each of the fin guide protrusions may have a peaked cross- sectional shape, which includes an upper end point as a top point, or may have a second bent part, which is formed by bending part of the edge of the fin guide protrusion inwards .

As well, a height (a) of each of the fin guide protrusions may be equal to or less than a thickness (c) of each of the radiation fins, which are brought into close contact with the respective upper and lower junction surfaces, and, preferably, may be 0.5mm or less.

In another aspect, the present invention provides a PTC heater, including a PTC rod made of an extruded tube, the PTC heater comprising: a PTC rod; a plurality of radiation fins, each of which integrally has fitting protrusions so that the PTC rod is fitted between the fitting protrusions of the radiation fins; a plurality of frame bars coupling the PTC rod and the radiation fins to each other, each of the frame bars having a first bent part, formed by curving an intermediate portion of the frame bar to have a shape that is convex towards the radiation fins; and a plurality of housings provided on respective longitudinal opposite ends of the frame bars, wherein the PTC rod is directly fitted between the fitting protrusions, the frame bars bring the radiation fins into close contact with the PTC rod using a force generated by stretching the first bent parts, and the housings hold the frame bars.

In an embodiment, an insulating plate, an electrode terminal, a PTC unit and a PTC element are stacked on each other in positional sequence from a bottom to a top in an internal space defined in the PTC rod, wherein the insulating plate, the electrode terminal, the PTC unit and the PTC element are brought into close contact with an inner surface of the internal space of the PTC rod by applying pressure to the upper and lower junction surfaces.

Each of the fitting protrusions may have a convex rounded edge. Alternatively, an edge of each of the fitting protrusions may have a peaked cross-sectional shape, which includes an upper end point as a top point, or may have a third bent part, which is formed by bending part of the edge of the fin guide protrusion inwards.

In a further aspect, the present invention provides a PTC rod made of an extruded tube, in an internal space of which an insulating plate, an electrode terminal, a PTC unit and a PTC element are stacked on each other in positional sequence from a bottom to a top, the PTC rod provided with radiation fins, wherein fin guide protrusions are integrally provided on respective opposite edges of each of upper and lower junction surfaces of the PTC rod, and the radiation fins are directly coupled to the respective junction surfaces formed between the fin guide protrusions.

In an embodiment, each of the fin guide protrusions may have a convex rounded edge . Alternatively, an edge of each of the fin guide protrusions may have a peaked cross- sectional shape, which includes an upper end point as a top point, or may have a second bent part, which is formed by bending part of the edge of the fin guide protrusion inwards .

Furthermore, a height (a) of each of the fin guide protrusions may be equal to or less than a thickness (c) of each of the radiation fins, which are brought into close contact with the respective upper and lower junction surfaces, and, preferably, may be 0.5mm or less.

[Advantageous Effects] In the PTC heater of the present invention, when manufacturing the PTC heater, radiation fins can be directly coupled to a PTC rod provided with fin guide protrusions, without manufacturing a separate fin guide. Furthermore, thanks to special shapes of frame bars, contact force between the radiation fins and the PTC rod can be increased, thus enhancing the durability of the PTC heater.

In addition, in the present invention, the height of each fin guide protrusion is equal to or less than the thickness of the radiation fin, and the edges of the fin guide protrusion have rounded, peaked or bent shapes. Therefore, there are effects in that air can smoothly flow through the radiation fins and the radiation fins can be easily assembled with the PTC rod.

[Description of Drawings]

FIG. 1 is an exploded perspective view of a conventional PTC (positive temperature coefficient) heater;

FIG. 2 is an assembled sectional view of a radiation fin and a PTC rod of FIG. 1; FIG. 3 is an assembled sectional view of a radiation fin and a PTC rod according to a modification of FIG. 1;

FIG. 4 is a front view of a PTC heater, according to a first embodiment of the present invention;

FIG. 5 is an exploded perspective view of internal construction elements of a PTC rod of FIG. 4;

FIG. 6 is an assembled sectional view of a radiation fin and a PTC rod of FIG. 4;

FIG. 7 is sectional views showing fin guide protrusions of FIG. 6; FIG. 8 is an assembled sectional view of a radiation fin and a PTC rod, according to a second embodiment of the present invention; and

FIG. 9 is sectional views showing fitting protrusions of FIG. 8. [Best Mode]

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings . Reference should now be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components. In the description of the present invention, detailed explanation of well-known functions and constructions will be omitted so that the present invention can be described more clearly.

FIG. 4 is a front view of a PTC (positive temperature coefficient) heater, according to a first embodiment of the present invention. FIG. 5 is an exploded perspective view of internal construction elements of a PTC rod of FIG. 4. FIG. 6 is an assembled sectional view of a radiation fin and a PTC rod of FIG. 4. FIG. 7 is sectional views showing fin guide protrusions of FIG. 6.

The PTC heater 1000 of the present invention consists of PTC rods, which are made of extruded tubes. In detail, the PTC heater 1000 includes radiation fins 300 and the PTC rods 100, which have therein upper and lower junction surfaces 122, each of which has a planar shape and is in close contact with one side of the corresponding radiation fin 300. Fin guide protrusions 110 are integrally provided on the respective opposite edges of each junction surface 122. The PTC heater 1000 further includes frame bars 500, which couple the PTC rods 100 and the radiation fins 300 to each other, and each of which has a first bent part 525 which is formed by curving the intermediate portion of the frame bar such that it is convex towards the radiation fins 300, and housings 600 and 700, which are provided on respective longitudinal opposite ends of the frame bars 500.

Furthermore, a radiation plate 325 is interposed between each frame bar 500 and the corresponding radiation fin 300. As shown in FIG. 5, a structure, which is formed by stacking an insulating plate 150, an electrode terminal 120, PTC units 142 and PTC elements 140 in positional sequence from the bottom to the top, is provided in an internal space 101 defined in each PTC rod 100. Referring to FIG. 6, the structure, which includes the insulating plate 150, the electrode terminal 120, the PTC units 142 and the PTC elements 140, is brought into close contact with the inner surface of the internal space 101 of the PTC rod 100 by applying inward pressure to the upper and lower junction surfaces 122.

The radiation plates 325 serve to evenly transmit the pushing force of the frame bars 500 to the radiation fins 300, thus preventing partial deformation of the radiation fins 300, which may be induced when the frame bars 500 directly contact and push the radiation fins 300.

As shown in FIG. 6, the fin guide protrusions 110 protrude upwards or downwards from respective opposite edges of the upper and lower surfaces of the PTC rod 100. As shown in FIG. 7A, each fin guide protrusion 110 may have a convex rounded edge. Alternatively, as shown in FIG. 7B, an edge of each fin guide protrusion may have a peaked cross-sectional shape, which has an upper end point 115 as the top point. As a further alternative, as shown in FIG. 7C, an edge of each fin guide protrusion may have a second bent part 116, which is formed by bending part of the edge of the fin guide protrusion inwards.

Thanks to the rounded, peaked or bent shape of the edges of the fin guide protrusions 110, air, which exchanges heat with the radiation fins 300, can smoothly flow through the radiation fins 300, and the radiation fins 300 can be easily assembled with the corresponding junction surface 122 formed between the associated fin guide protrusions 110.

Referring to FIGS 6 and 7, in this embodiment of the present invention, each radiation fin 300 is manufactured by bending an aluminum film, which has a thickness c of 0.5mm and has a width less than a distance between the opposite fin guide protrusions 110 of the corresponding PTC rod 100, into a zigzag shape.

Furthermore, the height a of each fin guide protrusion 110 is equal to or less than the thickness c of the radiation fin 300, which is brought into close contact with the junction surface 122, and, preferably, the height a of each fin guide protrusion 110 is 0.5mm or less.

The reason for this is that, if the height a is greater than the thickness c of the radiation fin 300, or is greater than 0.5mm, the fin guide protrusions interfere with the air that passes through the radiation fin 300.

Furthermore, in the case of FIG. 7A, the convex rounded edge of each fin guide protrusion preferably has a radius R of at least 0.2mm. FIG. 8 is an assembled sectional view of a radiation fin and a PTC rod, according to a second embodiment of the present invention. FIG. 9 is sectional views showing fitting protrusions of FIG. 8.

As shown in FIG. 4 and 8, a PTC heater according to this embodiment of the present invention also consists of PTC rods, which are- made of extruded tubes. In detail, the PTC heater includes PTC rods 100, each of which has an approximately rectangular shape, and radiation fins 300, each of which integrally has fitting protrusions 310 so that the corresponding PTC rod 100 is fitted between the fitting protrusions 310. The PTC heater further includes frame bars 500, which couple the PTC rods 100 and the radiation fins 300 to each other, and each of which has a first bent part 525 which is formed by curving the intermediate portion of the frame bar such that it is convex towards the radiation fins 300, and housings 600 and 700, which are provided on respective longitudinal opposite ends of the frame bars 500.

Furthermore, as shown in FIG. 5, a structure, which is formed by stacking an insulating plate 150, an electrode terminal 120, PTC units 142 and PTC elements 140 in positional sequence from the bottom to the top, is provided in an internal space 101 defined in each PTC rod 100. The structure, which includes the insulating plate 150, the electrode terminal 120, the PTC units 142 and the PTC elements 140, is brought into close contact with the inner surface of the internal space 101 of the PTC rod 100 by applying pressure to the upper and lower surfaces of the PTC rod inwards.

As shown in FIG. 8, the fitting protrusions 310 are disposed on respective opposite edges of a junction surface 320 between each radiation fin 300 and the corresponding PTC rod 100. As shown in FIG. 9A, each fitting protrusion 310 may have a convex rounded edge. Alternatively, as shown in FIG. 9B, an edge of each fitting protrusion may have a peaked cross-sectional shape, which has an upper end point 315 as the top point. As a further alternative, as shown in FIG. 9C, an edge of each fitting protrusion may have a third bent part 317, which is formed by bending part of the edge of the fitting protrusion inwards. Preferably, each fitting protrusion 310 has a height b of 0.5mm or less. The reason for this that, if the height b of the fitting protrusion is greater than 0.5mm, material is excessively consumed.

The operation of the PTC heater of the present invention will be explained herein below. Of the elements of the PTC heater 1000 of FIG. 4, the radiation fins 300 are directly coupled to the corresponding PTC rods 100 by fitting them between the corresponding fin guide protrusions 110, which are integrally provided on the PTC rods 100, as shown in FIG. 6. Some of the radiation fins 300 are coupled to the frame bars 500 through the radiation plates 325, which are interposed therebetween.

Furthermore, the frame bars 500 closely contact the radiation fins 300 with the PTC rods 100 using the elastic force generated by stretching the first bent parts 525. The housings 600 and 700 serve to hold the frame bars 500.

Meanwhile, in the second embodiment, the fitting protrusions 310 are integrally provided on each radiation fin 300, so that each PTC rod 100 is directly fitted between the corresponding fitting protrusions 310. The frame bars 500 closely contact the radiation fins 300 with the PTC rods 100 using the elastic force generated by stretching the first bent parts 525. The housings 600 and 700 serve to hold the frame bars 500. Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the present invention as disclosed in the accompanying claims. Therefore, the preferred embodiments described above do not limit the technical sprit of the present invention. In other words, the scope and sprit of the present invention is defined by the accompanying claims, rather than being limited by the embodiments described above. Furthermore, it is to be understood that all modifications, additions and substitutions which can be derived from the accompanying claims fall within the bounds of the present invention.

Claims

[CLAIMS] [Claim l]

A PTC (positive temperature coefficient) heater, including a PTC rod made of an extruded tube, the PTC heater comprising: a plurality of radiation fins (300) ; a PTC rod (100) having therein upper and lower junction surfaces (122) , each of which has a planar shape and is in close contact with one side of the corresponding radiation fin (300) , with fin guide protrusions (110) integrally provided on respective opposite edges of each of the junction surfaces (122) ; a plurality of frame bars (500) coupling the PTC rod

(100) and the radiation fins (300) to each other, each of the frame bars (500) having a first bent part (525) , formed by curving an intermediate portion of the frame bar to have a shape that is convex towards the radiation fins (300) ; and a plurality of housings (600) and (700) provided on respective longitudinal opposite ends of the frame bars (500) , wherein each of the radiation fins (300) is directly fitted between the corresponding fin guide protrusions (110), the frame bars (500) bring the radiation fins (300) into close contact with the PTC rod (100) using a force generated by stretching the first bent parts (525) , and the housings (600) and (700) hold the frame bars (500) .

[Claim 2]

The PTC heater according to claim 1, further comprising: a radiation plate (325) interposed between each of the frame bars (500) and the corresponding radiation fin (300) , which is in surface contact with the frame bar (500) .

[Claim 3] The PTC heater according to claim 2, wherein an insulating plate (150), an electrode terminal (120), a PTC unit (142) and a PTC element (140) are stacked on each other in positional sequence from a bottom to a top in an internal space (101) defined in the ■ PTC rod (100), wherein the insulating plate (150), the electrode terminal (120), the PTC unit (142) and the PTC element (140) are brought into close contact with an inner surface of the internal space (101) of the PTC rod (100) by applying pressure to the upper and lower junction surfaces (122) .

[Claim 4]

The PTC heater according to claim 2, wherein each of the fin guide protrusions (110) has a convex rounded edge.

[Claim 5]

The PTC heater according to claim 2, wherein an edge of each of the fin guide protrusions (110) has a peaked cross-sectional shape, which includes an upper end point (115) as a top point, or has a second bent part (116), which is formed by bending part of the edge of the fin guide protrusion inwards.

[Claim 6]

The PTC heater according to any one of claims 1 through 5, wherein a height (a) of each of the fin guide protrusions (110) is equal to or less than a thickness (c) of each of the radiation fins (300) , which are brought into close contact with the respective upper and lower junction surfaces (122) .

[Claim 7]

The PTC heater according to claim 6, wherein the height (a) of each of the fin guide protrusions (110) is 0.5mm or less.

[Claim 8] A PTC heater, including a PTC rod made of an extruded tube, the PTC heater comprising: a PTC rod (100) ; a plurality of radiation fins (300) , each of which integrally has fitting protrusions (310) so that the PTC rod (100) is fitted between the fitting protrusions (310) of the radiation fins (300) ; a plurality of frame bars (500) coupling the PTC rod (100) and the radiation fins (300) to each other, each of the frame bars (500) having a first bent part (525) , formed by curving an intermediate portion of the frame bar to have a shape that is convex towards the radiation fins (300) ; and a plurality of housings (600) and (700) provided on respective longitudinal opposite ends of the frame bars

(500) , wherein the PTC rod (100) is directly fitted between the fitting protrusions (310), the frame bars (500) bring the radiation fins (300) into close contact with the PTC rod

(100) using a force generated by stretching the first bent parts (525), and the housings (600) and (700) hold the frame bars (500) .

[Claim 9] The PTC heater according to claim 8, wherein an insulating plate (150), an electrode terminal (120), a PTC unit (142) and a PTC element (140) are stacked on each other in positional sequence from a bottom to a top in an internal space (101) defined in the PTC rod (100) , wherein the insulating plate (150) , the electrode terminal (120) , the PTC unit (142) and the PTC element (140) are brought into close contact with an inner surface of the internal space (101) of the PTC rod (100) by applying pressure to the upper and lower junction surfaces (122) .

[Claim 10]

The PTC heater according to claim 9, wherein each of the fitting protrusions (310) has a convex rounded edge.

[Claim 11]

The PTC heater according to claim 10, wherein an edge of each of the fitting protrusions (310) has a peaked cross-sectional shape, which includes an upper end point

(315) as a top point, or has a third bent part (317) , which is formed by bending part of the edge of the fin guide protrusion inwards .

[Claim 12]

A PTC rod made of an extruded tube, in an internal space (101) of which an insulating plate (150) , an electrode terminal (120), a PTC unit (142) and a PTC element (140) are stacked on each other in positional sequence from a bottom to a top, the PTC rod provided with radiation fins, wherein fin guide protrusions (110) are integrally provided on respective opposite edges of each of upper and lower junction surfaces (122) of the PTC rod (100), and the radiation fins (300) are directly coupled to the respective junction surfaces (122) formed between the fin guide protrusions (110) .

[Claim 13]

The PTC rod according to claim 12, wherein each of the fin guide protrusions (110) has a convex rounded edge.

[Claim 14]

The PTC rod according to claim 12, wherein an edge of each of the fin guide protrusions (110) has a peaked cross- sectional shape, which includes an upper end point (115) as a top point, or has a second bent part (116) , which is formed by bending part of the edge of the fin guide protrusion inwards,

[Claim 15]

The PTC rod according to any one of claims 12 through 14, wherein a height (a) of each of the fin guide protrusions (110) is equal to or less than a thickness (c) of each of the radiation fins (300), which are brought into close contact with the respective upper and lower junction surfaces (122) .

[Claim 16] The PTC rod according to claim 15, wherein the height (a) of each of the fin guide protrusions (110) is 0.5mm or less.