Position sensor with a sealing structure

Abstract

The utility model discloses a position sensor with sealing structure, include: shell and upper cover, two are the independent components of each other, and the assembly is limited to hold the cavity and the outgoing line mouth that communicates with holding the cavity, and the outgoing line mouth is limited to form the passage, the printed circuit board is located in holding the cavity, and one end of terminal is electrically connected with the printed circuit board, and the other end is extended to the outside of shell through the passage to be electrically connected with the wire harness. The shell is equipped with the continuous closed weld that extends around the joint circumferentially between upper cover, to realize the overall sealing of holding the cavity, the seal is arranged in the passage, and the seal and the passage wall at the outgoing line mouth are sealed cooperation, and the circumferential sealing of holding the cavity is formed at the passage. This structure provides reliable sealing under the oil immersion working condition, reduces epoxy glue consumption simultaneously, has the advantages of low cost, good manufacturability and high reliability.

Description

Technical Field

[0001] This utility model relates to the field of sensor packaging and sealing technology, specifically to a position sensor with a sealed structure suitable for harsh media environments such as complete immersion in oil. Background Technology

[0002] In the hydraulic, lubrication, and fuel systems of vehicles and industrial equipment, position sensors are often subjected to harsh environments involving complete or periodic immersion in oil, as well as thermal shock and vibration. This can lead to corrosion of metal components due to media penetration, short circuits or leakage at terminal-wiring harness connections, functional drift of PCBs and components caused by oil or moisture erosion, and seal fatigue cracking induced by thermal cycling and mechanical shock. To mitigate these risks, current mainstream mass production solutions often employ integral potting of epoxy resin (hereinafter referred to as "integral potting") within the sensor cavity to form a barrier and support layer.

[0003] However, in practical applications, integral potting technology leads to high material and manufacturing costs, and requires long-term heat preservation or multiple curing curves, which slows down production line cycle time. At the same time, due to the presence of PCB components, pins, and dead corners within the cavity, the flowability and venting of the potting compound are restricted, which easily forms bubbles, gaps, and pinholes, creating slow-permeation channels for the medium. These channels can amplify into leakage paths under thermal cycling later on.

[0004] Based on the above pain points, the industry has also developed several alternative or improvement paths:

[0005] Interface sealing is achieved by using elastomers such as O-rings and planar sealing rings in conjunction with structural steps. However, under oil immersion and large temperature differences, permanent compression deformation of the elastomer and swelling of the medium may reduce long-term sealing performance, and it is also sensitive to assembly tolerances and surface roughness. Utility Model Content

[0006] The present invention aims to solve at least one of the aforementioned problems existing in the prior art.

[0007] To address this, the present invention proposes a position sensor with a sealing structure, comprising: a housing and a top cover, which are independent components and, when assembled, define a receiving cavity and a wire outlet communicating with the receiving cavity, the wire outlet defining a channel; a printed circuit board disposed within the receiving cavity; one end of a terminal is electrically connected to the printed circuit board, and the other end extends through the channel to the outside of the housing for electrical connection with a wire harness; a continuous closed weld extending circumferentially around the housing and the top cover is provided to seal the receiving cavity as a whole; a sealing element is provided within the channel, the sealing element sealingly engaging with the channel wall at the wire outlet to form a circumferential seal on the receiving cavity at the channel.

[0008] In the above structural design, the first overall boundary seal is formed by the "circumferential continuous closed weld" between the outer shell and the top cover, cutting off the circumferential permeation path of the receiving cavity to the outside. A sealing element is set in the outlet channel to form the second circumferential seal, thereby improving the overall sealing reliability.

[0009] In a preferred embodiment, a continuous closed weld extending circumferentially around the joint between the outer shell and the top cover is provided, the weld forming a closed loop along the joint to achieve an overall seal of the receiving cavity.

[0010] In a preferred embodiment, the seal is an integrally injection-molded structural component and is integrally connected to at least one of the terminals.

[0011] In a preferred embodiment, the seal includes an annular body surrounding the channel, with a sealing groove formed within the annular body; a welded skirt facing the outlet for fixing and sealing the outlet by welding; and a plug-in end through which the terminal extends into the receiving cavity.

[0012] In a preferred embodiment, the connector is formed by a plurality of through holes, each through hole allowing a terminal to pass through and correspond to a corresponding solder point on the printed circuit board.

[0013] In a preferred embodiment, the welding skirt and the periphery of the outlet form a continuous closed joint, thereby forming a circumferential seal at the channel.

[0014] In a preferred embodiment, the seal has a sealing groove with an axial opening, the sealing groove is filled with sealant and fits against the periphery of the terminal, the sealant forming a sealing barrier around the terminal after curing.

[0015] In a preferred embodiment, the connection between the terminal and the wire harness is covered with an insulating layer formed by heat shrink tubing, the insulating layer being circumferentially attached between the outer surfaces of the terminal and the wire harness and covering the entire length of the solder joint area.

[0016] In a preferred embodiment, the connection between the seal and the outlet is fixed by welding, and the welding method is selected from laser welding, ultrasonic welding or hot plate welding.

[0017] In a preferred embodiment, the welding method between the outer shell and the upper cover is selected from laser welding, friction welding, or ultrasonic welding.

[0018] The position sensor proposed in this invention achieves a first overall seal through a continuous circumferential closed weld between the outer shell and the top cover; a sealing element with a welded skirt, sealing groove, and insertion end is arranged in the outlet channel to form a second circumferential seal with the channel wall; and sealant is locally filled in the groove to establish a third local sealing barrier around the terminal. Compared with overall potting, this structure can significantly reduce the amount of epoxy resin used and the curing time, reduce material and manufacturing costs, and "structure" the sealing function, making it more tolerant of dimensional tolerances, thermal cycling, and vibration, with higher long-term reliability, and facilitating mass production consistency control. Attached Figure Description

[0019] The present invention will now be described in detail with reference to the accompanying drawings and through non-limiting embodiments, wherein:

[0020] Figure 1 This is an exploded view of the position sensor of this utility model.

[0021] Figure 2 This is a detailed cross-sectional view of the sealing structure at the cable outlet channel.

[0022] Figure 3 This is an exploded view of the assembly of the seals, terminals, and wiring harness.

[0023] Figure 4 This is a schematic diagram of a single sealing component.

[0024] Explanation of reference numerals in the attached figures

[0025] 1. Outer casing; 2. Top cover; 3. Receiving cavity; 4. Cable outlet; 41. Channel; 5. Printed circuit board;

[0026] 6 Terminal; 7 Wiring harness; 8 Seal; 81 Ring body; 82 Welding skirt; 83 Sealing groove; 84 Sealing adhesive; 86 Wire insertion end; 861 Perforation; 87 Joint (welded joint); 9 Insulation layer (heat shrink tubing)

[0027] The accompanying drawings are schematic only and are not necessarily drawn to scale. They only show those parts necessary to illustrate the present invention, while other parts may be omitted or simply mentioned. The present invention may include other parts or components besides those shown in the drawings. Detailed Implementation

[0028] In the following description, numerous specific details are set forth to enable those skilled in the art to gain a more complete understanding of the present invention. However, it will be apparent to those skilled in the art that implementations of the present invention may not include some of these specific details. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. Rather, the present invention can be conceived to be practiced with any combination of the following features and elements, regardless of whether they relate to different embodiments. Therefore, the following features, embodiments, and advantages are for illustrative purposes only and should not be construed as elements or limitations of the claims unless expressly set forth in the claims.

[0029] The descriptions of orientation used in the following description, such as "upper" and "lower," are for convenience only and are not intended to limit the scope of the invention, unless otherwise stated. Furthermore, the terms "first" and "second" are used to describe components; these terms are used only to distinguish individual components and are not intended to limit the order or number of these components.

[0030] The following is for reference. Figures 1 to 4 This invention will be described in detail below. In the following description, this invention is described in conjunction with a position sensor used in motors or gearboxes to detect the rotation angle and position of a rotating shaft. Such sensors are typically immersed in oil and therefore require sealing. However, it should be understood that this invention is also applicable to any other sensors that require sealing.

[0031] like Figure 1 As shown, the position sensor includes a housing 1 and a top cover 2, which, when assembled, define a receiving cavity 3 and a cable outlet 4 communicating with the receiving cavity 3. The cable outlet 4 defines a channel 41. A printed circuit board 5 is disposed within the receiving cavity 3. One end of a terminal 6 is electrically connected to the printed circuit board 5, and the other end extends through the channel 41 to the outside of the housing 1 and is electrically connected to a wiring harness 7. A continuous closed weld extending circumferentially around the joint between the housing 1 and the top cover 2 is provided to seal the receiving cavity 3 as a whole. A sealing element 8 is provided within the channel 41, and the sealing element 8 seals against the channel wall at the cable outlet 4, forming a circumferential seal at the channel 41.

[0032] More specifically, such as Figure 2 As shown, the seal 8 includes an annular body 81, a welded skirt 82 facing the outlet 4, and a sealing groove 83 that opens axially. After welding, the welded skirt 82 and the periphery of the outlet 4 form a continuous closed joint 87. The sealing groove 83 is filled with sealant 84, which, after curing, adheres to the periphery of the terminal 6, forming a local sealing barrier around the terminal 6.

[0033] like Figure 3 and Figure 4As shown, the sealing element 8 is provided with a plug-in end 86, which is formed by multiple independent through holes 861. Each through hole 861 allows a terminal to pass through and corresponds to a solder point on the printed circuit board 5, thereby realizing the branching and positioning of the multi-core wire harness 7.

[0034] like Figure 2 As shown, the connection between terminal 6 and wire harness 7 is covered by an insulating layer 9 formed by heat shrink tubing. The insulating layer 9 is circumferentially attached between the outer surfaces of terminal 6 and wire harness 7 and covers the entire length of the welding connection area, providing electrical insulation and environmental protection.

[0035] The seal 8 can be made of thermoplastic elastomer (TPE), polyamide (PA), polybutylene terephthalate (PBT), or modified materials thereof, and can be integrally wrapped with or injection molded with the terminal 6. The connection between the seal 8 and the outlet 4 can be laser welding, ultrasonic welding, or hot plate welding; the connection between the outer shell 1 and the upper cover 2 can be laser welding, friction welding, or ultrasonic welding. Options can be selected based on materials and equipment.

[0036] For ease of understanding, this embodiment provides a functional description of the sealing path. The seal at the sensor includes at least the following levels:

[0037] - First-level seal (integral boundary): The circumferentially continuous closed weld between the outer shell 1 and the upper cover 2 constitutes an integral boundary seal for the receiving cavity 3. The weld is a closed loop, which can maintain circumferential integrity under thermal shock and vibration loads.

[0038] - Second-stage seal (circumferential channel): The sealing element 8 and the channel wall at the outlet 4 form a circumferential seal at the channel 41 position, blocking the penetration path of the medium along the channel wall-structure gap.

[0039] - Third-level sealing (partial enclosure, optional): After the sealant 84 in the sealing groove 83 is cured, it adheres to the periphery of the terminal 6, creating a partial enclosure for the terminal or wire passage to inhibit slow seepage along the cable braid layer.

[0040] When fully submerged in oil (such as ATF, engine oil, or fuel), the above-mentioned multi-stage seal can significantly shorten the medium penetration path, reduce the probability of leakage, and maintain seal continuity during thermal cycling.

[0041] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any variations and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope defined in the claims.

Claims

1. A position sensor with a sealed structure, comprising: The outer shell (1) and the top cover (2) are independent components. When assembled, they define a cavity (3). One end of the outer shell is provided with a cable outlet (4) communicating with the cavity (3). The cable outlet (4) defines a channel (41). A printed circuit board (5) is disposed in the cavity (3). A terminal (6) is electrically connected at one end to the printed circuit board (5) and extends through the channel (41) to the outside of the outer shell (1) to be electrically connected to a wire harness (7). The outer shell (1) and the top cover (2) are provided with a continuous closed weld extending circumferentially around their joint to seal the cavity (3) as a whole. A sealing element (8) is provided in the channel (41). The sealing element (8) is sealed to the channel wall at the cable outlet (4) to form a circumferential seal on the cavity (3) at the channel (41).

2. The position sensor with a sealed structure according to claim 1, characterized in that, A continuous closed weld extending circumferentially around the joint between the outer shell (1) and the upper cover (2) is provided, and the weld forms a closed loop along the joint to achieve overall sealing of the receiving cavity (3).

3. The position sensor with a sealed structure according to claim 1, characterized in that, The sealing element (8) is an integrally injection molded structural component and is integrally connected to at least one of the terminals (6).

4. The position sensor with a sealed structure according to claim 1, characterized in that, The connection between the terminal (6) and the wire harness (7) is covered with an insulating layer (9) formed by heat shrink tubing. The insulating layer (9) is circumferentially attached between the outer surfaces of the terminal (6) and the wire harness (7) and covers the entire length of the welding connection area.

5. The position sensor with a sealed structure according to claim 1, characterized in that, The connection between the sealing element (8) and the outlet (4) is fixed by welding, and the welding method is selected from laser welding, ultrasonic welding or hot plate welding.

6. The position sensor with a sealed structure according to claim 1, characterized in that, The welding method of the outer shell (1) and the upper cover (2) is selected from laser welding, friction welding or ultrasonic welding.

7. The position sensor with a sealed structure according to any one of claims 1 to 6, characterized in that, The sealing element (8) includes an annular body (81) disposed around the channel (41), the annular body (81) having a sealing groove (83) formed therein; a welded skirt (82) facing the outlet (4) for fixing to the outlet (4) by welding and forming a seal; and a plug end (86) through which the terminal (6) extends into the receiving cavity (3).

8. The position sensor with a sealed structure according to claim 7, characterized in that, The connector (86) is formed by a plurality of through holes (861), each of which allows a terminal (6) to pass through and correspond to a corresponding solder point on the printed circuit board (5).

9. The position sensor with a sealed structure according to claim 7, characterized in that, The welding skirt (82) and the periphery of the outlet (4) form a continuous closed joint (87), thereby forming a circumferential seal at the channel (41).

10. The position sensor with a sealed structure according to claim 7, characterized in that, The seal (8) is provided with a sealing groove (83) with an axial opening. The sealing groove (83) is filled with sealant (84) and fits against the periphery of the terminal (6). After curing, the sealant (84) forms a sealing barrier around the terminal (6).

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