A PTC thermistor heater and its heat dissipation substrate

Abstract

The present invention discloses a PTC thermistor heater and a heat dissipation substrate thereof, wherein the heat dissipation substrate comprises a cavity and a heat dissipation sheet arranged on the upper surface and / or the lower surface of the cavity; a first limiting rib and a second limiting rib are arranged in the cavity, which can limit the heating core and prevent its insulating film from bulging; the inner wall of the cavity is also provided with a first and a second accommodating groove which can accommodate the non-fixed side; the left side wall and the right side wall of the cavity are both arranged to have a tendency to deform inwards during press forming, and are provided with a first and a second avoidance gap to accommodate the space for deformation of the side walls; the above structural arrangement can avoid the problem of friction and extrusion damage to the insulating film / PTC sheet of the heating core by the left and right side walls during press forming, and can also avoid the problem of friction and extrusion damage to the insulating film / PTC sheet of the heating core by the first limiting rib and the second limiting rib, thereby completely solving the problems of electrical leakage and pipe explosion existing in the heater made of the heat dissipation substrate of the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of thermistor heaters, and in particular to a thermistor heater and a structural improvement of a heat dissipation substrate thereof. Background Art

[0002] Due to its unique characteristics, PTC (Positive Temperature Coefficient) thermistor heaters have the characteristics of automatic constant temperature, no open flame, long service life, little influence by power supply voltage fluctuations, and high electric heat conversion rate. They have been widely used in heaters, dryers, water heaters, air conditioners and other fields.

[0003] The PTC thermistor heater is usually formed by placing a PTC heating component in the cavity of an aluminum heat dissipation substrate and then pressing it. The PTC heating component includes a PTC sheet, a positive and negative metal electrode plate and an insulating film from the inside to the outside. The positive and negative metal electrode plates are respectively attached to the upper and lower surfaces of the PTC sheet for the electrodes, and the insulating film wraps the positive and negative metal electrode plates and the PTC sheet to play an insulating protection role.

[0004] The existing PTC thermistor heater has the problem that its heat dissipation base will damage the heating components in its cavity when it is pressed. One of the reasons is that when the heat dissipation base is pressed, its left and right walls will deform inwards, which will squeeze and rub the insulating film and PTC sheet, causing damage to the insulating film and PTC sheet, which will cause electrical leakage and pipe explosion safety problems during use. The Chinese utility model patent with announcement number CN 204859578 U has left and right side walls of the heat dissipation base concave inwards, and positioning strips are symmetrically arranged on the inner side. When the heat dissipation base is pressed, its side walls and positioning strips are deformed inwards. At this time, the positioning strips will squeeze and rub the insulating film and PTC sheet, causing damage to the insulating film and PTC sheet, which will lead to safety hazards such as electrical leakage and pipe explosion, causing safety concerns for users. In addition, the Chinese invention patent application with publication number CN108449812 A sets the limiting ribs in the heat dissipation matrix on the top wall and the bottom wall, and the left and right side walls are both inwardly concave arc surfaces. This structure can make the spacing protrusions of the heat dissipation matrix only displace in the vertical direction (the upper and lower spacing protrusions are close to each other) when the heat dissipation matrix is ​​pressed and formed, and no displacement occurs in the horizontal direction. The left and right side walls are deformed inward, and the spacing protrusions of this structure are displaced in the vertical direction, so that the side walls and the spacing protrusions have the opportunity to squeeze and rub the insulating film and PTC sheet, resulting in damage to the insulating film and PTC sheet, and then electrical leakage and pipe explosion problems. Because this defect of the prior art is related to personal and property safety, it is urgent to make improvements to ensure safety.

[0005] It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0006] In order to overcome the defects of the above-mentioned prior art, the embodiment of the present application provides a heat dissipation substrate, including a cavity, and a heat dissipation fin disposed on the upper surface and / or the lower surface of the cavity;

[0007] A first limiting rib and a second limiting rib are arranged in parallel with each other in the length direction of the cavity, and a gap for heating core installation is formed between the first limiting rib and the second limiting rib;

[0008] The fixed side of the first limiting rib and the fixed side of the second limiting rib are respectively connected to the upper wall and / or the lower wall on the side close to the left wall and the right wall in the cavity, and the height of the first limiting rib and the second limiting rib are both such that when the heating core is placed in the heating core installation gap, it can be limited and its insulating film can be prevented from bulging out of the heating core installation gap;

[0009] The inner wall of the cavity is further provided with a first accommodating groove capable of accommodating the non-fixed side at the non-fixed side corresponding to the first limiting rib, and a second accommodating groove capable of accommodating the non-fixed side at the non-fixed side corresponding to the second limiting rib;

[0010] The left side wall and the right side wall of the cavity are both configured to have a tendency to deform inwards during press forming, a first avoidance gap is provided between the first limiting rib and the left side wall of the cavity, and a second avoidance gap is provided between the second limiting rib and the right side wall of the cavity;

[0011] The upper surface and the lower surface of the cavity are respectively provided with pressing areas for pressing and forming extending along the length direction of the heat dissipation substrate.

[0012] The present invention can also adopt the following optional / preferred solutions:

[0013] There is a first spacing between the non-fixed side of the first limiting rib and the upper wall or lower wall in the cavity, and the height of the first spacing is not less than the distance the first limiting rib moves during press molding. There is a second spacing between the non-fixed side of the second limiting rib and the upper wall or lower wall in the cavity, and the height of the second spacing is not less than the distance the second limiting rib moves during press molding.

[0014] The non-fixed side of the first limiting rib is flush with the notch of the first containing groove, and the non-fixed side of the second limiting rib is flush with the notch of the second containing groove.

[0015] The distance from the bottom wall of the first accommodating groove to the non-fixed side of the first limiting rib is not less than the distance the first limiting rib moves during press molding, and the distance from the bottom wall of the second accommodating groove to the non-fixed side of the second limiting rib is not less than the distance the second limiting rib moves during press molding.

[0016] The height of the first limiting rib and the second limiting rib are not less than three quarters of the thickness of the heating core to be installed.

[0017] The left side wall and the right side wall of the cavity are both in an inwardly concave arc shape, so that when the heat dissipation substrate is pressed and formed, the left side wall and the right side wall of the cavity have a tendency to deform inward of the cavity.

[0018] Bending guide grooves are provided on the outer sides of the left and right walls of the cavity, and the bending guide grooves can make the left and right walls of the cavity tend to deform toward the inside of the cavity during press forming.

[0019] The notches of the first accommodating groove and the second accommodating groove are both rounded structures.

[0020] The present invention further provides a PTC thermistor heater, comprising a heat dissipation substrate and a heating core, wherein the heat dissipation substrate is the heat dissipation substrate as described in any one of the above items, and the heating core is installed in the heating core installation gap.

[0021] One or more technical solutions provided in the embodiments of the present application have at least the following beneficial effects compared with the prior art:

[0022] The left side wall and the right side wall of the cavity are arranged to have a tendency to deform inwards during press molding. Combined with the provision of the first avoidance gap and the second avoidance gap, the problem of friction and extrusion damage to the insulating film / PTC sheet of the heating core by the left and right side walls during press molding can be avoided. In addition, the provision of the first limiting rib and the second limiting rib can prevent the insulating film of the heating core from bulging, thereby avoiding the problem of friction and extrusion damage to the insulating film / PTC sheet of the heating core by the first limiting rib and the second limiting rib, thereby completely solving the problems of electrical leakage and pipe explosion existing in the heater made of the heat dissipation substrate in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a heat dissipation substrate of an embodiment;

[0024] Figure 2 is a schematic structural diagram of a heat dissipation substrate of another embodiment;

[0025] Figure 3 is a schematic structural diagram of a heat dissipation substrate of a third embodiment;

[0026] Figure 4 is a schematic structural diagram of a heat dissipation substrate of a fourth embodiment;

[0027] Figure 5A and Figure 5B is a structural schematic diagram of a heat dissipation substrate of an embodiment in which a bending guide groove structure is arranged on the side wall;

[0028] Figure 6 It is a schematic diagram of the main view of a PTC thermistor heater implementing a force;

[0029] Figure 7 yes Figure 6 Schematic diagram of top view of PTC thermistor heater.

[0030] Note: Above Figure 1 -The heat sink schematics in Figure 5 all include the heat sink core for easier understanding. DETAILED DESCRIPTION

[0031] The inventors discovered that the reason why the PTC thermistor heaters in the prior art still have problems with electrical leakage and tube explosion is that the insulating film on the outer layer of the heating core will bulge outward from the left and right sides and between the upper and lower limit ribs. When the upper and lower surfaces of the heat dissipation substrate are pressurized during the molding process, the upper and lower surfaces of the heat dissipation core will be pressed, which will cause the two sides of the insulating film to bulge more. When the limit ribs provided at the upper and lower ends of the left and right side walls of the heat dissipation substrate approach each other in the vertical direction, the bulging insulating film will be rubbed and squeezed from the top and bottom, causing the heating core to be misplaced, thereby causing damage to the insulating film and even damage to the PTC sheet wrapped in the insulating film.

[0032] The PTC thermistor heater of the embodiment of the present invention aims at the above problems of electrical leakage and pipe explosion, and makes a clever structural improvement starting from the heat dissipation substrate, which can avoid the insulation film and PTC sheet from being damaged, thereby solving the problems of electrical leakage and pipe explosion. The heat dissipation substrate includes a cavity, and a heat sink disposed on the upper surface and / or lower surface of the cavity. Usually, the heat sink is disposed on both sides, but it is not excluded that the heat sink is disposed on only one side in some use / installation situations.

[0033] A first limiting rib and a second limiting rib are arranged in parallel with each other along the length direction in the cavity, and a heating core installation gap is formed between the first limiting rib and the second limiting rib. In addition to limiting the heating core in the heating core installation gap, the first limiting rib and the second limiting rib are also used to shield the insulating film of the outer layer of the heating core, so that it will not contact and rub against the side wall, and will not be rubbed or squeezed by the positioning strips or spacing protrusions in the prior art. The fixed side of the first limiting rib and the fixed side of the second limiting rib are respectively connected to the upper wall and / or the lower wall on the left side and the right side of the cavity, and the height of the first limiting rib and the second limiting rib are both: when the heating core is placed in the heating core installation gap, the heating core can be limited and its insulating film can be prevented from bulging. The left side wall and the right side wall of the cavity are both designed to have a tendency to deform inward during press forming, a first avoidance gap is provided between the first limiting rib and the left side wall of the cavity, and a second avoidance gap is provided between the second limiting rib and the right side wall of the cavity, the first avoidance gap and the second avoidance gap respectively provide necessary deformation accommodating space for the left side wall and the right side wall of the cavity to deform inward.

[0034] The upper and lower surfaces of the cavity are provided with pressing areas for pressing and molding respectively, extending along the length direction of the heat dissipation substrate, so that the pressing equipment can apply molding pressure from the upper and lower surfaces of the cavity.

[0035] The heat dissipation substrate is usually made of aluminum tubes or aluminum profiles.

[0036] The following is combined with Figure 1-7 The present invention is further described in the following specific embodiments, wherein the same reference numerals represent the same components unless otherwise specifically stated. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the present invention and its application.

[0037] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing as well as for coupling or communication.

[0038] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0040] Embodiment 1

[0041] like Figure 1 As shown, the heat dissipation substrate 10 of this embodiment includes a cavity 11 and heat dissipation fins 12 arranged on the upper surface and the lower surface of the cavity.

[0042] A first limiting rib 13 and a second limiting rib 14 parallel to each other are arranged in the length direction in the cavity 11, and a heating core installation gap is between the first limiting rib 13 and the second limiting rib 14. The width of the heating core installation gap is greater than the width of the heating core 20 to be installed, so as to facilitate the installation operation of the heating core 20.

[0043] The fixed side of the first limiting rib 13 and the fixed side of the second limiting rib 14 are respectively connected to the lower wall on the left side wall 111 and the right side wall 112 of the cavity 11, and the upper wall of the cavity 11 is also provided with a first accommodating groove 115 for accommodating the non-fixed side corresponding to the first limiting rib 13, and a second accommodating groove 116 for accommodating the non-fixed side corresponding to the non-fixed side of the second limiting rib 14. The heights of the first limiting rib 13 and the second limiting rib 14 are both: the distance from the bottom wall of the first accommodating groove 115 to the non-fixed side of the first limiting rib 13 is not less than the distance the first limiting rib 13 moves during press molding, and the distance from the bottom wall of the second accommodating groove 16 to the non-fixed side of the second limiting rib 14 is not less than the distance the second limiting rib 14 moves during press molding. In this embodiment, the non-fixed side of the first limiting rib 13 is flush with the notch of the first accommodating groove 115, and the non-fixed side of the second limiting rib 14 is flush with the notch of the second accommodating groove 116, so that the insulating film 23 (the heating core 20) of the heating core 20 placed in the gap between the heating core and the heating core can be fixed. The core 20 includes a PTC sheet, a positive electrode sheet, a negative electrode sheet and the insulating film 23, the positive electrode sheet and the negative electrode sheet are respectively attached to the upper and lower surfaces of the PTC sheet, and the PTC sheet, the positive electrode sheet and the negative electrode sheet are wrapped by the insulating film 23 together and are restricted between the first limiting rib 13 and the second limiting rib 14, so that the insulating film 23 will not bulge out of the heating core installation gap, especially the left and right sides of the insulating film 23, and during the pressing process, the first limiting rib 13 and the second limiting rib 14 have no relative movement with the insulating film 23, so the insulating film 23 of the heating core 20 can be completely avoided from being damaged by friction, extrusion during pressing. In addition, the notches of the first receiving groove 115 and the second receiving groove 116 are preferably chamfered structures, but are not limited to this. For example, the first receiving groove 115 and the second receiving groove 116 may preferably have notch sizes larger than sizes of other parts. The two structures may have a guiding function, facilitating the non-fixed side of the first limiting rib 13 and the non-fixed side of the second limiting rib 14 to smoothly enter the first receiving groove 115 and the second receiving groove 116 respectively, thereby clearing obstacles for deformation during press molding and reducing the processing accuracy requirements for the product.

[0044] The left side wall 111 and the right side wall 112 of the cavity 11 are both designed to have a tendency to deform inwards during press forming, which is specifically achieved by making the left side wall 111 and the right side wall 112 of the cavity 11 both inwardly concave arcs. A first avoidance gap (i.e., the gap between the first limiting rib 13 and the left side wall 111 of the cavity 11) is also provided between the first limiting rib 13 and the left side wall 111 of the cavity 11, and a second avoidance gap (i.e., the gap between the second limiting rib 14 and the right side wall 112 of the cavity 11) is also provided between the second limiting rib 14 and the right side wall 112 of the cavity 11. The first avoidance gap and the second avoidance gap respectively provide necessary deformation accommodation space for the left side wall 111 and the right side wall 112 of the cavity 11 to deform inwards.

[0045] The upper and lower surfaces of the cavity 11 are provided with pressing areas 113 for pressing and molding respectively, which extend along the length direction of the heat dissipation substrate 10, so that the pressing equipment can apply molding pressure from the upper and lower surfaces of the cavity 11. The pressing area 113 is located on the outer side of the heat sink 12. Preferably, the inner side of the pressing area 113 on the left side is aligned with or biased to the left of the outer side of the first limiting rib 13, and the inner side of the pressing area 113 on the right side is aligned with or biased to the right of the outer side of the second limiting rib 14. Further preferably, the two pressing areas 113 on the left side of the upper and lower surfaces of the cavity 11 are symmetrical to each other, the two pressing areas 113 on the right side of the upper and lower surfaces of the cavity 11 are symmetrical to each other, the two pressing areas 113 on the left and right sides of the upper surface of the cavity 11 are symmetrical to each other, and the two pressing areas 113 on the left and right sides of the lower surface of the cavity 11 are symmetrical to each other.

[0046] Embodiment 2

[0047] The heat dissipation substrate 10 of this embodiment is as follows Figure 2 As shown, the main differences from the above-mentioned embodiment 1 are:

[0048] The fixed side of the first limiting rib 13 and the fixed side of the second limiting rib 14 are respectively connected to the upper wall on the left side wall 111 and the right side wall 112 of the cavity 11, and the lower wall of the cavity 11 is provided with a first accommodating groove 115 for accommodating the non-fixed side corresponding to the first limiting rib 13, and a second accommodating groove 116 for accommodating the non-fixed side corresponding to the non-fixed side of the second limiting rib 14.

[0049] Embodiment 3

[0050] The heat dissipation substrate 10 of this embodiment is as follows Figure 3 As shown, the main differences from the above-mentioned embodiment 1 are:

[0051] The fixed side of the first limiting rib 13 is connected to the lower wall of the cavity 11 on the side close to the left side wall 111, and the upper wall of the cavity 11 is provided with a first accommodating groove 115 for accommodating the non-fixed side corresponding to the first limiting rib 13; the fixed side of the second limiting rib 14 is connected to the upper wall of the cavity 11 on the side close to the right side wall 112, and the lower wall of the cavity 11 is also provided with a second accommodating groove 116 for accommodating the non-fixed side corresponding to the second limiting rib 14.

[0052] Embodiment 4

[0053] The heat dissipation substrate 10 of this embodiment is as follows Figure 4 As shown, the main difference from the aforementioned embodiment 1 is that: the fixed side of the first limiting rib 13 is connected to the upper wall of the cavity 11 on the side close to the left side wall 111, and the lower wall of the cavity 11 is provided with a first accommodating groove 115 for accommodating the non-fixed side corresponding to the first limiting rib 13; the fixed side of the second limiting rib 14 is connected to the lower wall of the cavity 11 on the side close to the right side wall 112, and the upper wall of the cavity 11 is also provided with a second accommodating groove 116 for accommodating the non-fixed side corresponding to the second limiting rib 14.

[0054] Embodiment 5

[0055] The heat dissipation substrate 10 of this embodiment is as follows Figure 5A and Figure 5B As shown, the main differences from the above-mentioned embodiment 1 are:

[0056] The left side wall 111 and the right side wall 112 of the cavity 11 are both configured to have a tendency to deform inward during press forming, which is specifically achieved in the following manner: a bending guide groove 114 is provided on the outer side of the left side wall 111 and the outer side of the right side wall 112 of the cavity 11, and the bending guide groove 114 can make the left side wall 111 and the right side wall 112 of the cavity 11 have a tendency to deform inward of the cavity 11 during press forming. Specifically, the bending guide groove 114 can be a groove provided at the upper and lower middle positions of the outer side of the left side wall 111 and the outer side of the right side wall 112 of the cavity 11, and the groove extends along the length direction of the heat dissipation substrate 10, and can be as follows: Figure 5A The arc groove shown, Figure 5B The various shapes such as the rectangular groove shown are formed by digging out part of the material of the outer side wall. The groove can make the strength of the side wall at this part lower than that at other parts, so that it is easier to deform during press forming and guide the deformation direction of the side wall to the outside.

[0057] Embodiment 6

[0058] A PTC thermistor heater, such as Figure 6 and Figure 7 As shown, it includes a heat dissipation substrate and a heating core 20. The heat dissipation substrate 10 is the heat dissipation substrate 10 as described in any of the above embodiments, and the heating core 20 is installed in the heating core installation gap.

[0059] The heating core 20 includes a PTC sheet, two lead-out electrode sheets 24 (a positive electrode sheet and a negative electrode sheet) and an insulating film 23. The two lead-out electrode sheets 24 are respectively attached to the upper and lower surfaces of the PTC sheet for lead-out. The PTC sheet and the lead-out electrode 24 are wrapped in the insulating film 23. The heating core 20 is inserted into the heating core insertion gap in the heat dissipation substrate 10, and after applying pressure to the pressing areas on the upper and lower surfaces of the heat dissipation substrate 10, the heat dissipation substrate 10 and the heating core 20 are pressed and formed to obtain the PTC thermistor heater.

[0060] The heat sink 12 is located on the upper and lower outer surfaces of the heat sink 10 (usually called the heat sink surface of the heat sink), and the heat sink 10 and the heat sink 12 are preferably an integrated structure, that is, the heat sink 12 is directly shoveled from the heat sink 10. The heat sink 10 is made of aluminum tube or aluminum profile.

[0061] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A heat dissipation substrate, characterized in that: It comprises a cavity, and a heat sink arranged on the upper surface and / or the lower surface of the cavity; A first limiting rib and a second limiting rib are arranged in parallel with each other in the length direction of the cavity, and a gap for heating core installation is formed between the first limiting rib and the second limiting rib; The fixed side of the first limiting rib and the fixed side of the second limiting rib are respectively connected to the upper wall and / or the lower wall on the left side wall and the right side wall of the cavity, and the height of the first limiting rib and the second limiting rib are both such that when the heating core is placed in the heating core installation gap, the heating core can be limited and its insulating film can be prevented from bulging out of the heating core installation gap. The inner wall of the cavity is further provided with a first accommodating groove capable of accommodating the non-fixed side at the non-fixed side corresponding to the first limiting rib, and a second accommodating groove capable of accommodating the non-fixed side at the non-fixed side corresponding to the second limiting rib; The left side wall and the right side wall of the cavity are both configured to have a tendency to deform inwards during press forming, a first avoidance gap is provided between the first limiting rib and the left side wall of the cavity, and a second avoidance gap is provided between the second limiting rib and the right side wall of the cavity; The upper and lower surfaces of the cavity are provided with pressing areas for pressing and forming respectively, extending along the length direction of the heat dissipation substrate; There is a first distance between the non-fixed side of the first limiting rib and the upper wall or lower wall in the cavity, and the first distance is not less than the distance the first limiting rib moves during press molding. There is a second distance between the non-fixed side of the second limiting rib and the upper wall or lower wall in the cavity, and the second distance is not less than the distance the second limiting rib moves during press molding.

2. The heat dissipation substrate according to claim 1, characterized in that: The non-fixed side of the first limiting rib is flush with the notch of the first containing groove, and the non-fixed side of the second limiting rib is flush with the notch of the second containing groove.

3. The heat dissipation substrate according to claim 1, characterized in that: The distance from the bottom wall of the first accommodating groove to the non-fixed side of the first limiting rib is not less than the distance the first limiting rib moves during press molding, and the distance from the bottom wall of the second accommodating groove to the non-fixed side of the second limiting rib is not less than the distance the second limiting rib moves during press molding.

4. The heat dissipation substrate according to claim 1, characterized in that: The height of the first limiting rib and the second limiting rib are not less than three quarters of the thickness of the heating core to be installed.

5. The heat dissipation substrate according to any one of claims 1 to 4, characterized in that: The left side wall and the right side wall of the cavity are both in an inwardly concave arc shape, so that when the heat dissipation substrate is pressed and formed, the left side wall and the right side wall of the cavity have a tendency to deform inward of the cavity.

6. The heat dissipation substrate according to any one of claims 1 to 4, characterized in that: Bending guide grooves are provided on the outer sides of the left and right walls of the cavity, and the bending guide grooves can make the left and right walls of the cavity tend to deform toward the inside of the cavity during press forming.

7. The heat dissipation substrate according to claim 2, 3 or 4, characterized in that: The notches of the first accommodating groove and the second accommodating groove are both rounded structures.

8. A PTC thermistor heater, comprising a heat dissipation substrate and a heating core, characterized in that: The heat dissipation substrate is the heat dissipation substrate as described in any one of claims 1 to 7, and the heating core is installed in the heating core installation gap.

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