Flat ceramic heating element

Abstract

The present invention provides a flat ceramic heating element comprising an outer conductive layer, an outer resistive layer, an inner insulating layer, and an inner insulating reinforcing layer. The outer conductive layer is arranged on the upper segments on both sides of the outer resistive layer, and positive and negative electrode portions are provided at the end faces of the outer conductive layer. The cross-section of the flat ceramic heating element is a rectangular structure. Furthermore, the flat ceramic heating element includes a top conductive layer that encloses the lower end of the outer resistive layer. Compared with conventional heating elements for left and right circuits, the intermediate flat ceramic heating element of the present invention omits the vertical insulating groove, thereby effectively improving product strength, avoiding premature failure due to periodic impacts of thermal stress, and also avoiding changes in resistance distribution and shifts in temperature range due to the sustained expansion of stress cracks.

Description

Technical Field

[0001] The present invention relates to a heating element, and particularly to a flat ceramic heating element.

Background Art

[0002] A ceramic heating element can be used as a heating element of an ignition mechanism as a conductor material, and ignition and heating are realized by the ceramic reaching an extremely high temperature when energized. Ceramic heating elements can be applied in fields such as engine ignition, gas stove ignition, water heater ignition, infrared sources, oxygen sensor heating, soldering iron heating, etc. The heating element made of ceramic material has advantages such as good starting performance, high temperature resistance, corrosion resistance, high strength, and long life.

[0003] Chinese Patent Application No. 109526079A discloses a high-voltage ceramic heating element including a main body portion. This main body portion has a hollow shape with an opening at the tail, and an elongated hole penetrating from left to right in the axial direction is provided in the main body portion. A temperature control region with a cross-sectional area smaller than that of the main body portion is provided in the outer resistance layer of the main body portion. By using this high-voltage ceramic heating element of this invention, the strength and use reliability of the product can be improved.

[0004] As a drawback, in this invention, by controlling the temperature control region using a functional layer structure, damage to the vulnerable part due to the up and down movement of the temperature region is avoided, and the service life of the ceramic heating element is extended. However, in actual use, as the use time elapses, especially when the temperature region is exposed during subsequent use, the temperature region gradually moves, and the problem that the temperature region of the ceramic body is not stable during use occurs.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to solve the problem in conventional technology where the temperature range of a ceramic heating element gradually shifts during use, resulting in an unstable temperature range for the ceramic body, this disclosure provides a flat ceramic heating element comprising an outer conductive layer, an outer resistive layer, an inner insulating layer, and an inner insulating reinforcing layer. [Means for solving the problem]

[0006] The outer conductive layer is arranged on the upper segments on both sides of the outer resistive layer, and positive and negative electrode portions are provided at the end faces of the outer conductive layer, and the cross-section of the flat ceramic heating element is rectangular.

[0007] In this solution, the flat ceramic heating element eliminates the elongated vertical holes of conventional high-voltage products, effectively improving product strength, avoiding quality defects in the elongated hole structure during manufacturing, ensuring control of the temperature range of the heating element during use, extending product life, and improving product acceptance rates. Furthermore, in conventional technology, the ceramic body can only be sintered from top to bottom in a vertical sintering process. In this solution, the ceramic heating element with a flat structure can be sintered in any direction during sintering, has the advantage of no deformation and rapid loading into the furnace, and improves product acceptance rates and processing efficiency.

[0008] Preferably, the flat ceramic heating element further comprises a top conductive layer that encloses the lower end of the outer resistive layer.

[0009] Preferably, the peripheral contour of the lower segment of the outer resistive layer is larger than the peripheral contour of the upper segment of the outer resistive layer, and the peripheral contour of the outer conductive layer is flush with the peripheral contour of the lower segment of the outer resistive layer.

[0010] Preferably, the flat ceramic heating element further comprises a molding passage that penetrates the top conductive layer, the outer resistive layer, the inner insulating layer, and the inner insulating reinforcing layer.

[0011] Preferably, a molding hole is provided at the bottom of the injection passage, and the diameter of the molding hole is smaller than the width of the molding passage.

[0012] Preferably, the lower end of the molding passage is connected to the molding hole via an arc-shaped segment.

[0013] Preferably, the lower end surface of the outer conductive layer tapers towards the center of the flat ceramic heating element. [Effects of the Invention]

[0014] This disclosure has the following advantageous effects:

[0015] 1. The plate-shaped ceramic heating element of this disclosure does not require the elongated vertical holes present in our existing high-voltage products, thereby effectively improving product strength and avoiding quality defects caused by the elongated hole structure during manufacturing. Furthermore, it ensures control of the temperature range of the heating element during use, extending the product life and improving the product's acceptance rate.

[0016] 2. The plate-shaped ceramic heating element of this disclosure has the advantages of being able to be sintered in any direction during sintering, being deformation-free, and being able to be quickly loaded into the furnace. This eliminates the need for conventional elongated hole structures, simplifies existing manufacturing processes, improves product acceptance rates, enhances processing efficiency, and reduces production costs. Product acceptance rates during manufacturing improve from 60% to over 95%.

[0017] 3. The flat ceramic heating element of the present invention has a switching life of 100,000 cycles or more. [Brief explanation of the drawing]

[0018] Figure 1 is a schematic diagram of an embodiment of the flat ceramic heating element of the present invention.

[0019] Figure 2 is a cross-sectional view along line AA in Figure 1. [Modes for carrying out the invention]

[0020] The following provides a more detailed explanation, along with specific embodiments.

[0021] 1. Definitions Electrodes: Electrodes are classified into a positive electrode and a negative electrode. The positive electrode is generally a cathode that gains electrons and undergoes a reduction reaction. The negative electrode is an anode that loses electrons and undergoes an oxidation reaction. Quadrangular structure: The quadrangular structure means the cross-section of the flat ceramic electrothermal element is quadrangular, different from the cylindrical structure or flat structure in the existing market. Peripheral contour: The peripheral contour refers to the outer surface.

[0022] 2. The reference numbers in the drawings of this specification include an electrode part 1, an outer resistance layer 2, an inner insulation layer 3, an inner insulation reinforcement layer 4, a head conductive layer 5, and a forming hole 6.

[0023] The embodiment is substantially as shown in FIG. 1. A flat ceramic electrothermal element with a quadrangular cross-section, the electrothermal element being a quadrangular structure, comprising, in order from the outside, a head conductive layer 5, an outer conductive layer, an outer resistance layer 2, an inner insulation layer 3, an inner insulation reinforcement layer 4, and a forming channel.

[0024] The head conductive layer 5 wraps around the lower end of the outer resistance layer 2. The lower end surface of the outer conductive layer tapers towards the center of the flat ceramic electrothermal element. The peripheral contour of the lower segment of the outer resistance layer 2 is larger than the peripheral contour of the upper segment of the outer resistance layer 2, and the peripheral contour of the outer conductive layer is flush with the peripheral contour of the lower segment of the outer resistance layer 2. Two electrode parts 1 are provided on the end surface of the outer conductive layer, and the two electrode parts 1 include a positive electrode part 1 and a negative electrode part 1. The positive electrode part 1 and the negative electrode part 1 of the outer conductive layer are respectively arranged on the upper segments on both sides of the outer resistance layer 2.

[0025] The forming passage penetrates through the head conductive layer 5, the outer resistance layer 2, the inner insulation layer 3, and the inner insulation reinforcement layer 4. A forming hole 6 is arranged at the bottom of the forming passage. The diameter of the forming hole 6 is smaller than the width of the forming passage. The lower end of the forming passage is connected to the forming hole 6 via an arcuate segment.

[0026] The above description is merely an embodiment of the present disclosure. Specific well-known structures, characteristics, and other common technical knowledge in the present solution are not described herein. A person skilled in the art would have known all common technical knowledge in the art to which this disclosure relates prior to the filing date or priority date, and would have mastered all existing technologies in that art and the ability to apply conventional experimental methods. A person skilled in the art could draw inspiration from this application and combine it with their own abilities to complete and implement the present solution. Some typical well-known structures or methods should not be considered an impediment to a person skilled in the art in implementing this application. A person skilled in the art should note that various modifications and improvements can be made without departing from the structure of this disclosure, and these will also be included within the scope of protection of this disclosure and will not affect the effectiveness and patentability of the disclosure. The scope of the invention claimed in this application is defined by the claims, and the detailed description in the specification and other descriptions are used to explain the content of the claims.

Claims

1. A flat ceramic heating element comprising an outer conductive layer, an outer resistive layer, an inner insulating layer, and an inner insulating reinforcing layer, wherein the outer conductive layer is arranged on the upper segments on both sides of the outer resistive layer, and a positive electrode portion and a negative electrode portion are provided on the end face of the outer conductive layer, characterized in that the cross-section of the flat ceramic heating element is square.

2. The flat ceramic heating element according to claim 1, further comprising a top conductive layer enclosing the lower end of the outer resistive layer.

3. The flat ceramic heating element according to claim 2, wherein the peripheral contour of the lower segment of the outer resistive layer is larger than the peripheral contour of the upper segment of the outer resistive layer, and the peripheral contour of the outer conductive layer is flush with the peripheral contour of the lower segment of the outer resistive layer.

4. The flat ceramic heating element according to claim 3, further comprising a molding passage penetrating the head conductive layer, the outer resistive layer, the inner insulating layer, and the inner insulating reinforcement layer.

5. A flat ceramic heating element according to any one of claims 1 to 4, wherein a molding hole is provided at the bottom of the injection passage, and the diameter of the molding hole is smaller than the width of the molding passage.

6. The flat ceramic heating element according to claim 5, wherein the lower end of the molding passage is connected to the molding hole via an arc-shaped segment.

7. A flat ceramic heating element according to any one of claims 1 to 6, wherein the lower end surface of the outer conductive layer tapers toward the center of the flat ceramic heating element.

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