Sealing structure for enhancing oil resistance between NTC (Negative Temperature Coefficient) wire and epoxy glue

Abstract

The utility model relates to the field of wire sealing, and discloses a sealing structure for enhancing oil resistance between an NTC (Negative Temperature Coefficient) wire and epoxy glue, which comprises an NTC sensing wire and a sealing assembly positioned between the NTC sensing wire and the epoxy glue, the sealing assembly comprises a metal tube and a Teflon connecting sleeve which are sleeved outside the NTC sensing wire, the metal tube comprises a bonding section and a cladding section, and the bonding section is connected with the cladding section. The bonding section is located at one end close to the transmission oil and is bonded and matched with the epoxy glue, the cladding section is located at one end far away from the transmission oil and is embedded in an annular cavity formed in the end part of the Teflon connecting sleeve, and the Teflon connecting sleeve is fixed with the cladding section and the wire skin of the NTC sensing wire in a cladding manner at the same time; the sealing time efficiency of the sealing structure can cover the life cycle of the whole product, and the sealing performance is remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of lead seal, especially to a sealing structure for enhancing the oil resistance between NTC lead and epoxy glue. BACKGROUND

[0002] At present, Teflon, as the king of plastics, can resist 300 DEG C high and -200 DEG C low temperature, and is widely used in various fields including new energy vehicle field, due to the low surface energy of Teflon, its surface does not stick to water and oil, leading to that when it is applied to NTC wire, the NTC wire is difficult to realize sealing function after durability when applied to the stator connector of new energy vehicle motor.

[0003] The existing NTC wire wrapped with Teflon wire skin is built in the plastic shell by pouring glue, one end of the NTC wire is connected with the plug of inverter, the other end is in contact with transmission oil, the NTC chip is at the transmission oil end, and is used for transmitting the measured stator temperature to the inverter through the NTC wire. Since the cooling mode of the motor is oil cooling, the molecules of transmission oil are small, and Teflon does not stick to oil, so the transmission oil can easily flow from the transmission oil end to the connector end along the gap between the Teflon wire and the epoxy glue, and adhere to the surface of the connector pin, leading to failure of temperature transmission.

[0004] The prior application with publication number CN212133925U discloses a sealing structure for enhancing the adhesion of NTC, comprising an NTC sensing wire, a PFA wire skin is arranged on the outer layer of the NTC sensing wire, a plurality of groups of heat shrink sleeve sealing elements are arranged on the PFA wire skin, each group of heat shrink sleeve sealing elements is composed of a plurality of heat shrink sleeves overlapping with each other, the heat shrink sleeve is made of fluororubber, the adhesion between the material of fluororubber and the epoxy glue is good, and the design can realize good sealing in a short period.

[0005] To realize sealing throughout the life cycle, in the test, high and low temperature durability experiment and high temperature durability experiment are needed, the high and low temperature durability experiment is a durability test of 270 cycles at a temperature range of -40 DEG C to 180 DEG C with 1.5 hours / cycle, and the high temperature durability experiment is a test of 600 hours at 180 DEG C, but it is found in actual test that the scheme of the above-mentioned patent can only maintain sealing for 300 hours at 180 DEG C in the high temperature durability experiment, and after 300 hours, a gap will appear between the fluororubber and the Teflon wire, leading to that transmission oil enters the connector end from the gap, and the product is invalid, and in the high and low temperature durability experiment, that is, in the temperature range of -40 DEG C to 180 DEG C, the connector end is filled with oil after 180 cycles with 1.5 hours / cycle, therefore, it is necessary to design a sealing structure for further prolonging the oil resistance of NTC wire. UTILITY MODEL CONTENTS

[0006] The utility model discloses to the sealing structure between the NTC line and epoxy glue can not cover the whole product's preset life cycle, will lead to product because of oil and cause the shortcoming of early failure, provide a kind of sealing structure for enhancing the oil resistance between NTC line and epoxy glue, can significantly improve sealing duration.

[0007] To solve the above technical problems, the utility model is solved by the following technical schemes:

[0008] A kind of sealing structure for enhancing the oil resistance between NTC line and epoxy glue, including NTC sensing line and the sealing assembly between NTC sensing line and epoxy glue, sealing assembly includes metal pipe and Teflon connecting sleeve of being set to NTC sensing line outside, metal pipe includes bonding section and cladding section, bonding section is located at the end close to transmission oil and is bonded with epoxy glue, cladding section is located at the end away from transmission oil and is embedded in annular chamber formed in the end of Teflon connecting sleeve, Teflon connecting sleeve is fused and fixed with cladding section and the wire skin of NTC sensing line simultaneously.

[0009] Using the above scheme, the surface of metal pipe itself can be high, can form dense bonding structure with epoxy glue, can meet the sealing demand of entire life cycle, but metal pipe needs to be sealed and fixed with the wire skin of NTC and always keep sealed state in entire life cycle, set Teflon connecting sleeve, when it is fused, can be fused on metal pipe and the wire skin of NTC to form an integral structure, block transmission oil, the sealing structure above can meet 700 hours of high-temperature durability under 180 DEG C high temperature after testing, and 270 cycles of high-low temperature durability in the temperature range of-40 DEG C ~ 180 DEG C at 1.5 hours / cycle.

[0010] As preferred, Teflon connecting sleeve is composed of first Teflon sleeve, second Teflon sleeve and variable-diameter Teflon heat shrink sleeve, the melting point of Teflon heat shrink sleeve is greater than the melting point of first Teflon sleeve and second Teflon sleeve, when Teflon heat shrink sleeve is heat shrunk, first Teflon sleeve and second Teflon sleeve are fused to form inner sealing structure between the wire skin of NTC sensing line, first Teflon sleeve, metal pipe and small-diameter section of Teflon heat shrink sleeve, metal pipe, second Teflon sleeve and large-diameter section of Teflon heat shrink sleeve form outer sealing structure.

[0011] Using the above scheme, the melting point of different kinds of Teflon is used to realize the inner sealing between metal pipe and NTC sensing line and the outer sealing between metal pipe and Teflon heat shrink sleeve, realize the effect of all-round oil blocking.

[0012] As preferred, the inner and outer surfaces of metal pipe are frosted.

[0013] Adopting the above scheme, the frosted surface further increases the surface energy and roughness of the metal pipe, and increases the tightness of the combination with the epoxy glue.

[0014] Preferably, the metal pipe is made of stainless steel.

[0015] Adopting the above scheme, the stainless steel has good corrosion resistance.

[0016] Preferably, the wall thickness of the first Teflon sleeve is greater than that of the second Teflon sleeve.

[0017] Preferably, the Teflon heat-shrinkable sleeve is made of PTFE, and the first and second Teflon sleeves are made of PFA.

[0018] Preferably, the wall thickness of the first Teflon sleeve is 0.25-0.4 mm, the wall thickness of the metal pipe is 0.45-0.6 mm, the wall thickness of the second Teflon sleeve is 0.1-0.15 mm, and the wall thickness of the Teflon heat-shrinkable sleeve is 0.15-0.2 mm.

[0019] Preferably, the length of the first Teflon sleeve is 30-40 mm, the length of the metal pipe is 35-45 mm, the length of the second Teflon sleeve is 10-20 mm, and the length of the Teflon heat-shrinkable sleeve is 30-40 mm.

[0020] Preferably, the sealing assembly is provided with at least one group along the axial direction of the NTC sensing wire.

[0021] The utility model discloses a sealing structure for enhancing the oil resistance between NTC wire and epoxy glue, which comprises a metal pipe, a Teflon heat-shrinkable sleeve, a first Teflon sleeve, a second Teflon sleeve and an NTC sensing wire. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a top view of a sealing structure for enhancing the oil resistance between NTC wire and epoxy glue in the embodiment;

[0023] Figure 2 is a left view of a sealing structure for enhancing the oil resistance between the NTC line and the epoxy glue of the embodiment;

[0024] Figure 3 is a sectional view of A-A of Figure 2

[0025] Figure 4 is a split view of the NTC sensing line and the sealing assembly of the embodiment.

[0026] The part names referred to by the respective numbers in the above drawings are as follows: A, potting area; B, transmission oil area; 1, NTC sensing line; 2, epoxy glue; 3, metal pipe; 4, Teflon heat shrink sleeve; 5, first Teflon sleeve; 6, second Teflon sleeve. DETAILED DESCRIPTION

[0027] The utility model will be described in further detail below in combination with the drawings and embodiments.

[0028] A sealing structure for enhancing the oil resistance between the NTC line and the epoxy glue, referring to Figures 1-4 as shown, comprising an NTC sensing line 1 and a sealing assembly located between the NTC sensing line 1 and the epoxy glue 2, the sealing assembly is provided with at least one set along the axial direction of the NTC sensing line 1, the diameter of the NTC sensing line 1 is 2.8 mm, the wire skin is made of PFA, the sealing assembly comprises a metal pipe 3 and a Teflon connecting sleeve sleeved outside the NTC sensing line 1, the metal pipe 3 is made of stainless steel, the inner and outer surfaces of the metal pipe 3 are formed into frosted surfaces through a sandblasting process, the wall thickness of the metal pipe 3 is 0.5 mm, the outer diameter of the pipe is 4.5 mm, the inner diameter of the pipe is 3.5 mm, and the length is 40 mm.

[0029] The metal pipe 3 comprises a bonding section and a cladding section, the bonding section is located at one end close to the transmission oil and is bonded and matched with the epoxy glue, the cladding section is located at one end away from the transmission oil and is embedded in an annular chamber formed at the end of the Teflon connecting sleeve, and the Teflon connecting sleeve is simultaneously cladded and fixed with the cladding section and the wire skin of the NTC sensing line 1.

[0030] The Teflon connecting sleeve is composed of a first Teflon sleeve 5 made of PFA, a second Teflon sleeve 6 made of PFA and a Teflon heat shrink sleeve 4 made of PTFE, the wall thickness of the first Teflon sleeve 5 is 0.35 mm, the outer diameter of the pipe is 3.5 mm, the inner diameter of the pipe is 2.8 mm, and the length is 35 mm; the wall thickness of the second Teflon sleeve 6 is 0.1 mm, the outer diameter of the pipe is 4.7 mm, the inner diameter of the pipe is 4.5 mm, and the length is 15 mm; the wall thickness of the Teflon heat shrink sleeve 4 is 0.15 mm, the outer diameter of the pipe is 3.5 mm, the inner diameter of the pipe is 2.8 mm, and the length is 35 mm.

[0031] ​The Teflon heat-shrink sleeve 4 is a variable-diameter structure, and the first Teflon sleeve 5, the Teflon heat-shrink sleeve 4 and the second Teflon sleeve 6 form the annular chamber for inserting the cladding section of the metal pipe 3, and since the melting point of PTFE is higher than that of PFA, when the Teflon heat-shrink sleeve 4 is heat-shrunk, the first Teflon sleeve 5 and the second Teflon sleeve 6 are fused and cladded on the inner and outer annular walls of the cladding section of the metal pipe 3 and form an integrated structure.

[0032] Referring to Figure 1 As shown in the figure, when the NTC sensing wire 1 is installed, a part is located in the transmission oil area B and another part is located in the potting area A, the potting area A is filled with the epoxy glue 2, and the sealing structure is designed to limit the transmission oil from entering the connector end along the wire skin of the NTC sensing wire 1 by using the low surface energy characteristics of Teflon. The design principle of the scheme of the application is that the metal pipe 3 itself has high surface energy, which can form a dense bonding structure between the metal pipe 3 and the epoxy glue, meeting the sealing requirements in the whole life cycle, but the metal pipe 3 needs to be able to realize sealing and fixation with the wire skin of the NTC and the sealing between them also needs to cover the whole life cycle. Based on this, a Teflon connecting sleeve is set by using the characteristics of different melting points of different types of Teflon, the Teflon connecting sleeve is composed of the Teflon heat-shrink sleeve 4, the first Teflon sleeve 5 and the second Teflon sleeve 6, and by using the characteristics that the first Teflon sleeve 5 and the second Teflon sleeve 6 are fused when the Teflon heat-shrink sleeve 4 is heat-shrunk, the metal pipe 3, the Teflon heat-shrink sleeve 4, the first Teflon sleeve 5 and the second Teflon sleeve 6 form an integrated structure, and the second Teflon sleeve 6 is fused and combined with the wire skin of the NTC sensing wire 1, realizing a high-efficiency sealing structure. The sealing structure can meet the high-temperature durability of 700 hours at 180℃ after testing, and the high-temperature and low-temperature durability of 270 cycles at 1.5 hours / cycle in the temperature range of-40℃ to 180℃.

[0033] The preferred embodiments of the application have been described above, the protection scope of the application is not limited to the above-mentioned embodiments, any technical scheme falling within the idea of the application belongs to the protection scope of the application. It should be noted that, for ordinary technical personnel in the technical field, some improvements and decorations without departing from the principle of the application are also regarded as the protection scope of the application.

Claims

1. A sealing structure for enhancing the oil resistance between an NTC sensor wire and an epoxy resin, comprising an NTC sensor wire (1) and a sealing assembly located between the NTC sensor wire (1) and the epoxy resin (2), characterized in that: The sealing assembly includes a metal tube (3) fitted over the NTC sensor line (1) and a Teflon connecting sleeve. The metal tube (3) includes an adhesive section and a cladding section. The adhesive section is located at the end close to the transmission oil and is bonded to the epoxy resin (2). The cladding section is located at the end away from the transmission oil and is embedded in the annular cavity formed at the end of the Teflon connecting sleeve. The Teflon connecting sleeve is clad and fixed to both the cladding section and the sheath of the NTC sensor line (1).

2. The sealing structure for enhancing the oil resistance between the NTC wire and the epoxy adhesive according to claim 1, characterized in that: The Teflon connecting sleeve consists of a first Teflon sleeve (5), a second Teflon sleeve (6), and a variable-diameter Teflon heat-shrink sleeve (4). The melting point of the Teflon heat-shrink sleeve (4) is greater than that of the first Teflon sleeve (5) and the second Teflon sleeve (6). When the Teflon heat-shrink sleeve (4) is heat-shrinked, the first Teflon sleeve (5) and the second Teflon sleeve (6) melt, forming an inner sealing structure between the wire sheath of the NTC sensing wire (1), the first Teflon sleeve (5), the metal tube (3), and the small-diameter section of the Teflon heat-shrink sleeve (4). The large-diameter section of the metal tube (3), the second Teflon sleeve (6), and the Teflon heat-shrink sleeve (4) forms an outer sealing structure.

3. A sealing structure for enhancing the oil resistance between an NTC wire and epoxy adhesive according to claim 1, characterized in that: The inner and outer surfaces of the metal tube (3) are frosted.

4. A sealing structure for enhancing the oil resistance between an NTC wire and epoxy adhesive according to claim 1, characterized in that: The metal tube (3) is made of stainless steel.

5. A sealing structure for enhancing the oil resistance between an NTC wire and epoxy adhesive according to claim 2, characterized in that: The wall thickness of the first Teflon sleeve (5) is greater than that of the second Teflon sleeve (6).

6. A sealing structure for enhancing the oil resistance between an NTC wire and epoxy adhesive according to claim 2, characterized in that: The Teflon heat shrink sleeve (4) is made of PTFE, and the first Teflon sleeve (5) and the second Teflon sleeve (6) are made of PFA.

7. A sealing structure for enhancing the oil resistance between an NTC wire and epoxy adhesive according to claim 2, characterized in that: The wall thickness of the first Teflon sleeve (5) is 0.25-0.4 mm, the wall thickness of the metal tube (3) is 0.45-0.6 mm, the wall thickness of the second Teflon sleeve (6) is 0.1-0.15 mm, and the wall thickness of the Teflon heat shrink sleeve (4) is 0.15-0.2 mm.

8. A sealing structure for enhancing the oil resistance between an NTC wire and epoxy adhesive according to claim 2, characterized in that: The length of the first Teflon sleeve (5) is 30-40 mm, the length of the metal tube (3) is 35-45 mm, the length of the second Teflon sleeve (6) is 10-20 mm, and the length of the Teflon heat shrink sleeve (4) is 30-40 mm.

9. A sealing structure for enhancing the oil resistance between an NTC wire and epoxy adhesive according to any one of claims 1 to 8, characterized in that: At least one set of sealing components is provided at axial intervals along the NTC sensing line (1).

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