Wire harness fixing piece and capacitive liquid level sensor

Abstract

The utility model discloses a wire harness fixing piece and a capacitive liquid level sensor, which are particularly suitable for being applied to an LNG (Liquefied Natural Gas) tank body. A wire harness fixing part is used for electrically connecting a wire harness with an inner sleeve and an outer sleeve in a capacitive liquid level sensor, a shielding layer of the wire harness is electrically connected with the outer sleeve, and the wire harness fixing part comprises a first part made of a conductive material, arranged on a wire core of the wire harness in a sleeving mode and fixed relative to the inner sleeve, and a second part made of a conductive material, the wire core is electrically connected with the inner sleeve; the second part is arranged on an inner insulating layer of the wire harness in a sleeving manner; the third part is made of an insulating material, is sleeved on an outer insulating layer of the wire harness and is fixed relative to the outer sleeve and the inner sleeve respectively; wherein the second part is respectively and relatively fixed with the first part and the third part, and the second part is fixedly connected with an inner insulating layer of the wire harness.

Description

Technical Field

[0001] The utility model belongs to the field of liquid level sensors, and in particular relates to a wire harness fixing component and a capacitive liquid level sensor, which is particularly suitable for application in LNG tanks. Background Art

[0002] The capacitive liquid level sensor mainly realizes the detection of capacitance by setting inner and outer sleeves, making the inner and outer sleeves serve as the positive and negative electrodes respectively, and immersing the liquid to be measured between the inner and outer sleeves to connect the inner and outer sleeves, thereby realizing the detection of capacitance and completing the measurement of liquid level height according to the capacitance value.

[0003] In the prior art, the wiring harness for a capacitive liquid level sensor primarily consists of a shielding layer, an insulating layer, and a wire core, arranged in this order from outside to inside. The shielding layer is electrically connected to the outer sleeve. The exposed wire core is encased in a straight, metal-made wire harness holder. Solder is applied to the wire core ends and the holder's filler to secure the holder to the wire core. The holder is then welded to the inner sleeve using a fixing plate, achieving an electrical connection between the wire core and the inner sleeve.

[0004] The problem is that since the wire core is secured to the harness holder and the inner sleeve solely through welding, a high welding force is required, which results in a long welding time. However, since the wire core is mostly copper, prolonged welding can easily cause the wire core to break or become damaged, significantly reducing the service life of the capacitive liquid level sensor. Utility Model Content

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a wire harness fixing member and a capacitive liquid level sensor, which solve the problem that the wire harness is easily broken when fixed to the inner and outer sleeves.

[0006] To achieve the above-mentioned objectives, the first aspect of the present invention adopts the following technical solutions: a wiring harness fixing part, used to electrically connect the wiring harness to the inner sleeve and the outer sleeve respectively in a capacitive liquid level sensor, and the shielding layer of the wiring harness is electrically connected to the outer sleeve, and the wiring harness fixing part includes: a first part, made of conductive material, sleeved on the wire core of the wiring harness and fixed relative to the inner sleeve to electrically connect the wire core and the inner sleeve; a second part, sleeved on the inner insulating layer of the wiring harness; a third part, made of insulating material, sleeved on the outer insulating layer of the wiring harness and fixed relative to the outer sleeve and the inner sleeve respectively; wherein, the second part is fixed relative to the first part and the third part respectively, and the second part is fixedly connected to the inner insulating layer of the wiring harness.

[0007] As an embodiment of the present utility model, the second part includes a first matching part and a second matching part, the first matching part is arranged on a side close to the first part and is fixedly connected to the first part to form a core wire terminal, and the second matching part is arranged on a side close to the third part and is fixedly connected to the third part to form an isolation sleeve, wherein the core wire terminal is made of conductive material and the isolation sleeve is made of insulating material.

[0008] As an embodiment of the present invention, the first matching piece is squeezed and fixed to the inner insulating layer of the wiring harness; and the end of the first part away from the second part is welded and fixed to the wire core of the wiring harness.

[0009] According to a second aspect of the present invention, a capacitive liquid level sensor is provided, comprising an inner sleeve, an outer sleeve, a wiring harness and the wiring harness fixing member described in the first aspect of the present invention, which is used to electrically connect the wiring harness to the inner sleeve and the outer sleeve respectively through the wiring harness fixing member in the capacitive liquid level sensor; the wiring harness comprises a wire core, an inner insulating layer, an outer insulating layer and a shielding layer which are sequentially sleeved from the inside to the outside, the wire core and the shielding layer are made of conductive material, and the inner insulating layer and the outer insulating layer are made of insulating material; the outer insulating layer, the inner insulating layer and the wire core increase in length in the direction approaching the interior of the liquid level sensor; the inner sleeve is arranged in the outer sleeve and spaced apart from the outer sleeve, the top end of the inner sleeve is lower than the top end of the outer sleeve, and the outer sleeve is electrically connected to the shielding layer; the first part of the wiring harness fixing member is used to electrically connect the wire core and the inner sleeve, and the third part is relatively fixed to the outer sleeve and the inner sleeve.

[0010] As an embodiment of the present invention, it further includes an inner positioning block and a support frame, the outer side of the support frame is fixedly connected to the outer sleeve, and the inner side is fixedly connected to the inner positioning block, and the inner positioning block is at least relatively fixed to the third part.

[0011] As an implementation manner of the present invention, the support frame is made of a conductive material, and the support frame is fixed to the shielding layer by welding.

[0012] As an implementation manner of the present invention, the inner positioning block is fixed to the third portion by interference fit; and / or the inner positioning block is fixed to the support frame by welding.

[0013] As an embodiment of the present invention, it further includes an external positioning block, which is arranged between the internal positioning block and the inner sleeve to relatively fix the internal positioning block and the inner sleeve; wherein the external positioning block is made of insulating material.

[0014] As an embodiment of the present invention, it further includes a fixing plate, one side of which is fixedly connected to the inner sleeve and the first part, and the fixing plate is made of a conductive material.

[0015] As an implementation manner of the present utility model, the wiring harness is a low-temperature wire.

[0016] In summary, compared with the prior art, the beneficial technical effect of the present invention is that, through the solution provided by the present invention, firstly, due to the existence of the second part, the second part is fixedly connected to the inner insulating layer. Since the second part is relatively fixed to the first part, the connection between the first part and the wire core only needs to be electrically connected. That is, although the fixation of the first part and the wire core also needs to be considered, since it is not the main source of fixing force, there is no need to consider the fixing force requirement between the low-temperature wire and the wire harness fixing part. Therefore, while ensuring the fixing force, the damage and breakage of the wire core can be reduced as much as possible, thereby improving the manufacturing quality of the entire capacitive liquid level sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 The figure is a structural diagram of a wiring harness fixing structure of a capacitive liquid level sensor provided by a specific embodiment of the present utility model.

[0019] Description of reference numerals:

[0020] 100, wiring harness fixing member; 101, core wire terminal; 102, isolation sleeve; 110, first part; 120, second part; 121, first matching part; 122, second matching part; 130, third part;

[0021] 200, low-temperature wire; 210, wire core; 220, inner insulation layer; 230, outer insulation layer; 240, shielding layer;

[0022] 300, inner positioning block; 400, outer positioning block; 500, fixing plate; 600, support frame; 700, welding end;

[0023] 10. Inner sleeve; 20. Outer sleeve. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present invention, unless otherwise specified, the directional words used, such as "up", "down", "left", "right", "front", and "back", generally refer to the up, down, left, and right of the device in actual use or working state, specifically the drawing direction in the accompanying drawings.

[0025] It should be noted that the order of description of the following embodiments does not limit the preferred order of the embodiments of the present invention. In addition, in the following embodiments, the description of each embodiment has its own focus. For parts not described in detail in one embodiment, please refer to the relevant description of other embodiments.

[0026] See also Figure 1 The figure shows a wiring harness fixing structure for a capacitive liquid level sensor. It is used to better fix the wiring harness in the capacitive liquid level sensor, including a wiring harness, an inner sleeve 10, an outer sleeve 20, a wiring harness fixing member 100 and a positioning support frame 600.

[0027] The wiring harness is preferably a low-temperature wire 200, which can be well adapted to the low-temperature environment when used in the LNG tank body. For example, it can still be used normally at -200°C. The low-temperature wire 200 preferably includes a fixed and electrically isolated wire core 210, an inner insulating layer 220, an outer insulating layer 230 and a shielding layer 240, which are sequentially arranged from the inside to the outside. The wire core 210 and the shielding layer 240 are preferably made of conductive materials. Preferably, the wire core 210 is made of copper. The shielding layer 240 is preferably formed by metal foil, metal braided mesh or metal spiral winding. As for its material, as long as it can conduct electricity, there is no specific limitation. For example, it can be made of copper foil, aluminum foil, tinned copper, silver-plated copper and other materials.

[0028] The wiring harness fixture 100 includes a first portion 110, a second portion 120, and a third portion 130, which are relatively fixed. The first portion 110 has a first cavity to accommodate the core 210 of the cryogenic wire 200, the second portion 120 has a second cavity to accommodate the inner insulating layer 220 of the cryogenic wire 200, and the third portion 130 has a third cavity to accommodate the outer insulating layer 230 of the cryogenic wire 200. Since the core 210, inner insulating layer 220, and outer insulating layer 230 are arranged from the inside out, it is naturally understood that the sizes of the first, second, and third cavities are arranged from small to large.

[0029] The size of the first cavity is smaller than that of the inner insulating layer 220, thereby allowing the first cavity to accommodate only the core 210 of the cryogenic cable 200 but not the inner insulating layer 220. It is understood that the size of the second cavity is not smaller than that of the inner insulating layer 220 of the cryogenic cable 200 and smaller than that of the outer insulating layer 230, allowing the second cavity to accommodate the inner insulating layer 220 but not the outer insulating layer 230. Similarly, the size of the third cavity is smaller than that of the shielding layer 240 and not smaller than that of the outer insulating layer 230.

[0030] It should be noted that the dimensions of the aforementioned wire core 210, inner insulation layer 220, outer insulation layer 230, and shielding layer 240 primarily refer to their outer diameters after they are sequentially sheathed and fixed to form the low-temperature wire 200. For example, the dimension of the inner insulation layer 220 refers to the outer diameter of the inner insulation layer 220 after it is sheathed on the wire core 210; the dimension of the outer insulation layer 230 refers to the outer diameter of the outer insulation layer 230 after it is sheathed on the inner insulation layer 220; and the dimension of the shielding layer 240 refers to the outer diameter of the shielding layer 240 after it is sheathed on the outer insulation layer 230.

[0031] At the same time, in order to make the wire core 210, the inner insulating layer 220, and the outer insulating layer 230 contact the first part 110, the second part 120, and the third part 130 respectively, it is preferred that the lengths of the wire core 210, the inner insulating layer 220, and the outer insulating layer 230 in the liquid level sensor are increased in sequence, thereby realizing that part of the wire core 210 is exposed outside the inner insulating layer 220 to contact the first part 110, part of the inner insulating layer 220 is exposed outside the outer insulating layer 230 to contact the second part 120, and part of the outer insulating layer 230 is exposed outside the shielding layer 240 to contact the third part 130. Figure 1 In this specific embodiment, since the liquid level sensor is arranged in the vertical direction, the length of the core 210 in the liquid level sensor is longer than the length of the inner insulating layer 220, the length of the inner insulating layer 220 is longer than the length of the outer insulating layer 230, and the length of the outer insulating layer 230 is longer than the length of the shielding layer 240. Naturally, it can be understood that Figure 1 In the embodiment, the first portion 110 , the second portion 120 and the third portion 130 of the harness fixing member 100 are arranged from bottom to top.

[0032] Please continue reading Figure 1The inner sleeve 10 and the outer sleeve 20 are coaxially arranged, the inner sleeve 10 is sleeved inside the outer sleeve 20 and are electrically isolated from each other. The first part 110 of the wiring harness fixture 100 is made of a conductive material, and the third part 130 is made of an insulating material. The outer wall of the first part 110 of the wiring harness fixture 100 is fixedly electrically connected to the inner sleeve 10, and the inner wall is fixedly electrically connected to the core 210 of the low-temperature wire 200 as a positive electrode. The third part 130 of the wiring harness fixture 100 is fixedly connected to the outer sleeve 20, and the shielding layer 240 of the low-temperature wire 200 is electrically connected to the outer sleeve 20 as a negative electrode.

[0033] Therefore, when it is necessary to use the capacitive liquid level sensor for measurement, for example, the capacitive liquid level sensor is placed in an LNG tank. At this time, LNG is contained between the inner sleeve 10 and the outer sleeve 20, and the inner sleeve 10 and the outer sleeve 20 are connected by LNG. At this time, the height of the liquid level can be calculated according to the capacitance at different heights, thereby realizing the calibration of the liquid level sensor.

[0034] Please continue reading Figure 1 The inner wall of the first portion 110 contacts the wire core 210. The first portion 110 and the wire core 210 are fixed together by welding to form a welded terminal 700. The second portion 120 is at least partially fixedly connected to the inner insulating layer 220. This arrangement is intended to significantly reduce the requirements for securing the first portion 110 and the wire core 210, thereby ensuring the service life of the entire liquid level sensor. The securing of at least a portion of the second portion 120 to the inner insulating layer 220 will be described in detail below.

[0035] It should be noted that this is particularly significant because, due to the special material properties of the wire core 210 and the cost requirements of mass production, welding is often required to achieve an electrical connection between the wire core 210 and the first portion 110 during the process of securing the wire core 210 to the wire harness holder 100. In the prior art, since the wire core 210 and the first portion 110 need to be both electrically connected and securely secured, the welding process requires stacking materials to ensure securement, which in turn requires a long welding time. However, this increased welding time can directly lead to poor welding quality or damage and breakage of the wire core 210 during the prolonged welding process, resulting in a high defect rate for the entire capacitive liquid level sensor.

[0036] However, through the solution provided by the present utility model, first, due to the existence of the second part 120, the second part 120 is fixedly connected to the inner insulating layer 220. Since the second part 120 is relatively fixed to the first part 110, at this time, for the connection between the first part 110 and the wire core 210, only electrical connection needs to be achieved. That is, although the fixation of the first part 110 and the wire core 210 also needs to be considered, since it is not the main source of the fixing force, the fixing force requirement between the cryogenic wire 200 and the wire harness fixing part 100 does not need to be considered. Furthermore, while ensuring the fixing force, the damage and fracture of the wire core 210 can be reduced as much as possible, and the manufacturing quality of the entire capacitive liquid level sensor can be improved.

[0037] Furthermore, as described above, the first part 110 is made of a conductive material, and the third part 130 is made of an insulating material. In order to reduce the manufacturing difficulty and cost in the entire manufacturing process, the second part 120 includes a separately arranged first matching part 121 and a second matching part 122, and both the first matching part 121 and the second matching part 122 are sleeved on the inner insulating layer 220. Among them, the first matching part 121 is arranged in the direction close to the first part 110, and the second matching part 122 is arranged in the direction close to the third part 130. The first matching part 121 and the first part 110 are integrally arranged to form a core wire terminal 101, and the core wire terminal 101 is made of a conductive material. The second matching part 122 and the third part 130 are integrally arranged, and then form an isolation sleeve 102, and the isolation sleeve 102 is made of an insulating material.

[0038] Preferably, the outer diameters of the first matching part 121 and the first part 110 are the same, and the outer diameters of the second matching part 122 and the third part 130 are the same, so that the isolation sleeve 102 and the core wire terminal 101 form a "U" - shaped structure similar to having a through - hole, in order to better adapt to industrial manufacturing.

[0039] Thus, by dividing the second part 120 into the first matching part 121 and the second matching part 122, and making the first matching part 121 and the second matching part 122 be integrally arranged with the first part 110 and the second part 120 respectively, the preparation requirements for the second part 120 in the production manufacturing process can be well reduced, and further, it is better facilitated for large - scale industrial production.

[0040] When it is necessary to install the wire harness fixator 100 and the cryogenic wire 200, first, the isolation sleeve 102 is sleeved on the inner insulating layer 220 and the outer insulating layer 23 of the cryogenic wire 200, so that the third part 130 of the isolation sleeve 102 is sleeved on the outer insulating layer 230, and the second matching part 122 is sleeved on the inner insulating layer 220. Subsequently, the core wire terminal 101 is sleeved on the inner insulating layer 220 and the wire core 210 of the cryogenic wire 200, so that the first matching part 121 of the core wire terminal 101 is sleeved on the inner insulating layer 220, and the first part 110 is sleeved on the wire core 210 and contacts the wire core 210.

[0041] The first matching piece 121 of the second part 120 is fixedly connected to the inner insulating layer 220. The advantage of such a setting is that by making the first matching piece 121 interference-connected with the inner insulating layer 220, the position of the second matching piece 122 relative to the low-temperature line 200 can be indirectly fixed, thereby achieving the relative position fixation of the first part 110, the second part 120 and the third part 130, that is, achieving the relative position fixation of the core wire terminal 101 and the isolation sleeve 102 and the low-temperature line 200.

[0042] Preferably, the first matching piece 121 and the inner insulating layer 220 are fixed by extrusion. The advantage of this arrangement is that the operator can adjust the fixed position of the first matching piece 121 and the inner insulating layer 220 in real time to ensure that the core wire terminal 101 and the isolation sleeve 102 in each liquid level sensor are set in appropriate positions to ensure the quality of the entire tooling process.

[0043] More preferably, the first matching piece 121 and the inner insulating layer 220 are extruded through a hexagonal tooling. The advantage of such a setting is that the force on the inner insulating layer 220 can be made more uniform, thereby ensuring uniform force on the entire low-temperature line 200 and avoiding the problem of wire core 210 breakage caused by uneven force.

[0044] Please continue reading Figure 1 The wiring harness fixing structure of the capacitive liquid level sensor also includes an inner positioning block 300 , an outer positioning block 400 , a support frame 600 and a fixing plate 500 .

[0045] The fixing plate 500 is made of a conductive material and is fixedly electrically connected to the inner wall of the inner sleeve 10. The fixing plate 500 is provided with a mounting hole that matches the core terminal 101, so that the outer wall of the core terminal 101 is fixedly electrically connected to the fixing plate 500. Preferably, the fixing plate 500 is fixed to the inner sleeve 10 and the core terminal 101 by welding, so as to achieve electrical conductivity between the first portion 110 and the inner sleeve 10 while ensuring installation stability.

[0046] In order to better fix the inner sleeve 10, the outer sleeve 20, the low-temperature wire 200 and the wiring harness fixing part 100, the inner sleeve 10 and the outer sleeve 20 are arranged so that the top of the inner sleeve 10 is lower than the top of the outer sleeve 20, that is, the inner sleeve 10 is lower than the outer sleeve 20 at the top.

[0047] The inner positioning block 300 is mounted on at least a portion of the outer wall of the isolation sleeve 102 and does not electrically contact the core wire terminal 101. Preferably, the inner positioning block 300 forms an interference fit with the isolation sleeve 102. The outer side of the support frame 600 is fixedly electrically connected to the outer sleeve 20, while the inner side is fixedly connected to the inner positioning block 300. The shielding layer 240 of the cryogenic wire 200 is fixedly mounted on the support frame 600 and electrically connected to the support frame 600. Thus, by electrically connecting the outer sleeve 20, the support frame 600, and the shielding layer 240, it can be used as a negative electrode.

[0048] The outer positioning block 400 is mounted between the inner positioning block 300 and the inner sleeve 10, connecting the inner positioning block 300 and the inner sleeve 10 together. This prevents electrical conduction between the inner positioning block 300 and the inner sleeve 10, thus preventing short circuits and ensuring the proper operation of the entire capacitive liquid level sensor.

[0049] Furthermore, the inner positioning block 300 is preferably made of metal material. The advantage of this arrangement is that it can well realize the welding fixation of the inner positioning block 300, the support frame 600 and the outer cylinder, ensuring the fixing force while reducing the difficulty of tooling, thereby reducing the difficulty of batch manufacturing of the entire capacitive liquid level sensor.

[0050] Furthermore, the outer positioning block 400 is preferably made of insulating material, such as PTFR insulating material, so that the inner sleeve 10 and the inner positioning block 300 are relatively fixed. Preferably, the outer positioning block 400 is interference-connected with the inner sleeve 10 and the inner positioning block 300 respectively.

[0051] It is naturally understood that the present invention also provides a capacitive liquid level sensor, including the aforementioned wiring harness fixing structure of the capacitive liquid level sensor.

[0052] The above is a detailed introduction to the scheme of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0053] Reference throughout this specification to "one embodiment," "an embodiment," or "a specific embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention, and not necessarily in all embodiments. Thus, various appearances of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the invention may be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the invention described and illustrated herein are possible in light of the teachings herein and are considered part of the spirit and scope of the invention.

[0054] It should also be understood that one or more of the elements shown in the figures may also be implemented in a more separate or more integrated manner, or even removed because they are inoperable in certain circumstances or provided because they may be useful depending on the application.

[0055] In addition, unless otherwise expressly indicated, any marking arrows in the drawings should be regarded as illustrative only and not limiting. Furthermore, unless otherwise indicated, the term "or" as used herein is generally intended to mean "and / or." Where a term is unclear in providing separation or combination capabilities, the combination of components or steps will also be considered as indicated.

Claims

1. A wiring harness fixture for electrically connecting a wiring harness to an inner sleeve and an outer sleeve in a capacitive liquid level sensor, wherein the shielding layer of the wiring harness is electrically connected to the outer sleeve, characterized in that: include: The first part is made of a conductive material, is sleeved on the wire core of the wire harness and is fixed relative to the inner sleeve so that the wire core and the inner sleeve are electrically connected; The second part is sleeved on the inner insulating layer of the wiring harness; The third part is made of insulating material and is sleeved on the outer insulating layer of the wiring harness and is fixed relative to the outer sleeve and the inner sleeve respectively; The second portion is fixed relative to the first portion and the third portion respectively, and the second portion is fixedly connected to the inner insulating layer of the wiring harness.

2. The wire harness fixing member according to claim 1, wherein: The second part includes a first matching piece and a second matching piece, wherein the first matching piece is arranged on a side close to the first part and fixedly connected to the first part to form a core wire terminal, and the second matching piece is arranged on a side close to the third part and fixedly connected to the third part to form an isolation sleeve, wherein The core wire terminal is made of conductive material, and the isolation sleeve is made of insulating material.

3. The wire harness fixing member according to claim 2, wherein: The first matching piece is fixed to the inner insulating layer of the wiring harness by extrusion; and one end of the first part away from the second part is fixed to the wire core of the wiring harness by welding.

4. A capacitive liquid level sensor, characterized in that: comprising an inner sleeve, an outer sleeve, a wiring harness, and a wiring harness fixing member according to any one of claims 1 to 3, for electrically connecting the wiring harness to the inner sleeve and the outer sleeve respectively through the wiring harness fixing member in the capacitive liquid level sensor; The wiring harness includes a wire core, an inner insulating layer, an outer insulating layer, and a shielding layer, which are sequentially sheathed from the inside to the outside. The wire core and the shielding layer are made of a conductive material, and the inner insulating layer and the outer insulating layer are made of an insulating material. The outer insulating layer, the inner insulating layer, and the wire core increase in length in a direction approaching the interior of the liquid level sensor. The inner sleeve is arranged in the outer sleeve and spaced apart from the outer sleeve, the top of the inner sleeve is lower than the top of the outer sleeve, and the outer sleeve is electrically connected to the shielding layer; The first portion of the wiring harness fixing piece is used to electrically connect the wire core and the inner sleeve, and the third portion is fixed relatively to the outer sleeve and the inner sleeve.

5. The capacitive liquid level sensor according to claim 4, characterized in that: It also includes an inner positioning block and a support frame, the outer side of the support frame is fixedly connected to the outer sleeve, and the inner side is fixedly connected to the inner positioning block, and the inner positioning block is at least relatively fixed to the third part.

6. The capacitive liquid level sensor according to claim 5, characterized in that: The support frame is made of conductive material, and the support frame is fixed to the shielding layer by welding.

7. The capacitive liquid level sensor according to claim 6, characterized in that: The inner positioning block is fixed to the third portion by interference fit; and / or the inner positioning block is fixed to the support frame by welding.

8. The capacitive liquid level sensor according to claim 5, characterized in that: It also includes an external positioning block, which is arranged between the internal positioning block and the inner sleeve to fix the internal positioning block and the inner sleeve relatively; The outer positioning block is made of insulating material.

9. The capacitive liquid level sensor according to any one of claims 4 to 6, characterized in that: It also includes a fixing plate, which is fixedly connected to the inner sleeve and the first part, and the fixing plate is made of a conductive material.

10. The capacitive liquid level sensor according to any one of claims 4 to 6, characterized in that: The wiring harness is a low-temperature wire.

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