Sensor housing and sensor

Abstract

The utility model provides a sensor shell, which is provided with a bottom wall (1) and a circumferential side wall (2) vertically extending from the outer periphery of the bottom wall, the bottom wall (1) is provided with a longitudinal center line along the length direction and a transverse center line along the width direction, and the projection of the bottom wall (1) on a horizontal plane is rectangular; the cross section of the bottom wall (1) taken along the longitudinal centerline is a first arched cross section (1a) with a first curvature radius (R1), the cross section of the bottom wall taken along the transverse centerline is a second arched cross section (1b) with a second curvature radius (R2), and the first curvature radius is larger than the second curvature radius; the bottom wall is provided with a convex upper surface (11) and a concave lower surface (12), and the convex upper surface (11) and the circumferential side wall (2) define a containing cavity (3) for the printed circuit board. The utility model also provides a sensor comprising the sensor housing.

Description

Technical Field

[0001] The utility model relates to the technical field of sensors, in particular to a sensor housing with a structure capable of resisting thermal deformation, and a sensor with such a sensor housing, such as a position sensor, especially a non-contact position sensor. Background Art

[0002] For traditional sensor designs, the bottom surface of the housing is usually designed as a flat surface, and support ribs are added on both sides to enhance the strength to resist thermal deformation. A printed circuit board (PCB) is installed on the housing to detect the target position of the client, and its detection function and accuracy highly depend on the position accuracy of the PCB.

[0003] The housing material of the sensor is usually plastic, with poor heat-resistant deformation ability. It is generally applied in the environment of -40°C to 150°C, and has a large thermal deformation in a high-temperature environment. This thermal deformation will greatly affect the position of the PCB in the housing for detecting the client target, thereby affecting the detection accuracy of the sensor, and even causing the sensor function to fail seriously in severe cases.

[0004] The sensor needs to have good high-temperature deformation resistance to ensure the accuracy of the product's electronic function, and the product size is limited to a relatively small range and should not be too large. Summary of the Invention

[0005] The purpose of the utility model is to provide a sensor housing with a novel housing structure design. This sensor housing is particularly suitable for non-contact position sensors and has good heat-resistant deformation ability.

[0006] To this end, the utility model provides a sensor housing, which has a bottom wall and a circumferential side wall vertically extending from the outer peripheral edge of the bottom wall. The bottom wall has a longitudinal center line along its length direction and a transverse center line along its width direction, and its projection on the horizontal plane is a rectangle; the cross-section of the bottom wall intercepted along the longitudinal center line is a first arched cross-section with a first radius of curvature, the cross-section of the bottom wall intercepted along the transverse center line is a second arched cross-section with a second radius of curvature, and the first radius of curvature is greater than the second radius of curvature; and the bottom wall has a convex upper surface and a concave lower surface, and a receiving chamber for the printed circuit board is defined by the convex upper surface and the circumferential side wall.

[0007] Compared with the traditional sensor housing with a flat bottom wall, for the rectangular housing of the present utility model, the bottom wall is designed as an arc surface with different curvatures in the length and width directions, so that the bottom wall and the circumferential side wall fit well, and the arch structure of the bottom wall with the ability to resist deformation is retained. This kind of sensor housing has better ability to resist high-temperature deformation, reduces the deformation of the printed circuit board installation area, thereby avoiding affecting the function of the sensor; and this kind of sensor housing has high space utilization rate and better curvature.

[0008] According to a preferred embodiment of the present utility model, the circumferential side wall has an upper edge and a lower edge, and the outer peripheral edge of the bottom wall is located in the same plane and is substantially flush with the lower edge.

[0009] According to an embodiment of the present utility model, the first radius of curvature and the second radius of curvature are preferably defined by the following relational expressions:

[0010] R1 = L / sin(180° - 2arctan(L / H));

[0011] R2 = W / sin(180° - 2arctan(W / H));

[0012] Wherein, L is the length of the bottom wall, W is the width of the bottom wall, and H is the vertical distance between the center point of the concave lower surface and the plane where the outer peripheral edge of the bottom wall is located. This kind of sensor housing designs a new structure within the space range of the traditional designed housing, and has excellent high-temperature thermal deformation resistance without the need to increase additional space.

[0013] According to an embodiment of the present utility model, the bottom wall includes a first arc section and a second arc section having a first radius of curvature, and a third arc section and a fourth arc section having the second radius of curvature, wherein the first arc section and the second arc section are opposite to each other in the length direction of the bottom wall, and the third arc section and the fourth arc section are opposite to each other in the width direction of the bottom wall.

[0014] In a preferred embodiment, there are fillet transition parts between the first arc section and the third arc section, between the first arc section and the fourth arc section, between the second arc section and the third arc section, and between the second arc section and the fourth arc section. Design between two arc sections

[0015] According to an embodiment of the present utility model, a rectangular planar section is provided at the center position of the bottom wall, and the rectangular planar section is located between the first arc section and the second arc section and between the third arc section and the fourth arc section.

[0016] According to one aspect of the present utility model, the sensor housing further has a plurality of support columns extending from the convex upper surface of the bottom wall, such as four support columns, and the printed circuit board is fixedly mounted to the accommodation chamber of the sensor housing through the plurality of support columns.

[0017] In a preferred aspect, in order to improve the structural strength of the sensor housing, the sensor housing further includes a first reinforcing rib extending outward from the convex upper surface and a second reinforcing rib extending outward from the concave lower surface. Among them, the projection of the bottom wall on the horizontal plane is preferably a rounded rectangle, and the first reinforcing rib and the second reinforcing rib are grid-shaped reinforcing ribs connected to the circumferential side wall.

[0018] The present utility model also provides a sensor, which includes the above-mentioned sensor housing and a printed circuit board arranged in the sensor housing. This sensor is preferably a position sensor, such as a non-contact position sensor. It should be understood that such a sensor housing is not limited to being applied to a non-contact position sensor and can be applied to any housing design with requirements for high-temperature deformation resistance.

[0019] The present utility model provides a novel sensor housing structure. By designing the bottom wall of the sensor housing to have an arched cross-section, the sensor housing has better resistance to high-temperature deformation in a high-temperature environment (such as 150 °C), reducing the loss of sensor accuracy caused by thermal deformation and reducing the risk of induction failure. And considering the semi-open structure of the sensor and its thermal deformation trend, the rectangular bottom wall of the housing is designed as an arched structure, and reinforcing ribs are added on both sides of the arched structure. This structure significantly reduces the high-temperature thermal deformation of the housing, ensuring higher accuracy of the fixed PCB position, and at the same time, the low-temperature deformation ability is similar to the original design. This sensor housing designs a new structure within the housing space of the traditional design, has excellent high-temperature thermal deformation resistance without the need to increase additional space, is structurally stable and beautiful. And through finite element analysis, it can be known that the thermal deformation amount has decreased by about 15% compared with the existing design. Description of the Drawings

[0020] The features and advantages of the present utility model will be clearly understood through the following detailed description with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and thus cannot be regarded as a limitation to the present utility model, where:

[0021] Figure 1 Shows a top perspective view of an embodiment of the sensor housing of the present utility model;

[0022] Figure 2 is Figure 1 a bottom perspective view of the shown sensor housing;

[0023] Figure 3 A sectional view taken along the longitudinal center line A-A of the bottom wall of the sensor housing shown; Figure 1

[0024] Figure 4 A sectional view taken along the transverse center line B-B of the bottom wall of the sensor housing shown; Figure 1

[0025] Figure 5A Shows an embodiment of the bottom wall of the sensor housing according to the present utility model;

[0026] Figure 5B Shows another embodiment of the bottom wall of the sensor housing according to the present utility model;

[0027] Figure 6 A sectional view of an embodiment of a sensor according to the present utility model, showing a printed circuit board mounted within the sensor housing;

[0028] Figure 7 A schematic structural view of an embodiment of a sensor according to the present utility model in cooperation with a target block of a client; and

[0029] Figure 8A and Figure 8B A comparative deformation diagram of an embodiment of a sensor according to the present utility model and a sensor of a conventional design. Detailed implementation manners

[0030] Embodiments of the present utility model will be described below with reference to the accompanying drawings. In the following description, many specific details are set forth in order to enable those skilled in the art to more fully understand and implement the present utility model. In addition, it should be understood that the present utility model is not limited to the specific embodiments introduced. On the contrary, the present utility model can be implemented by any combination of the various features and elements described below, regardless of whether they relate to different embodiments. Therefore, the aspects, features, embodiments and advantages described below are for illustrative purposes only and should not be regarded as elements or limitations of the claims, unless expressly recited in the claims.

[0031] In a sensor, especially a position sensor, the PCB fixed on the sensor housing is an important sensing element, and the position of the PCB is the most important parameter of the sensor, directly affecting the detection range and accuracy of the sensor. At high temperatures, the plastic housing often deforms, affecting the position of the PCB and thus the function of the sensor.

[0032] ​​In the structural design of a sensor housing, for a square housing (such as a rectangle or a square), if a spherical surface (a sphere or an ellipsoid) is designed as the supporting surface (the shape of the bottom wall), it is difficult to solve the problem that the distances between the contours formed at the intersection of the square and the spherical surface and the square edges are unequal. If a spherical surface is used in combination with a square, the peripheral distance gap is relatively large, and its structural deformation resistance ability is limited. Similar problems exist for an ellipsoidal surface.

[0033] In response to this, for the square housing, the present application designs arc surfaces with different curvatures in the length and width directions, so that it fits well with the square housing and retains the deformation resistance ability of its arch shape.

[0034] In the following text, terms such as "first" and "second" are used to describe the elements of the present application. These terms are only used to distinguish each element, rather than to limit the nature, order or number of these elements. The terms "comprising" and "having" are used to express an open inclusive meaning, and mean that there may be additional elements / components in addition to the listed elements / components.

[0035] Figure 1 and Figure 2 FIG. shows a perspective view of an embodiment of a sensor housing according to the present invention. As can be seen from the figure, the sensor housing 10 has a bottom wall 1 and a circumferential side wall 2 vertically extending from the outer peripheral edge of the bottom wall. In this embodiment, the bottom wall 1, especially the projection of the bottom wall 1 on the horizontal plane, is rectangular, such as a rounded rectangle. Such a sensor housing is generally referred to as a rectangular housing. Here, the bottom wall 1 has a length and a width, and has a longitudinal center line A-A along its length direction and a transverse center line B-B along its width direction. The housing material of the sensor housing is usually a plastic material, and its heat deformation resistance ability is poor.

[0036] See Figure 3 , which shows a cross-sectional view of the sensor housing 10 taken along the longitudinal center line A-A. As can be seen from the figure, the cross-section of the bottom wall 1 taken along this longitudinal center line is a first arched cross-section 1a having a first radius of curvature R1.

[0037] See Figure 4 , which shows a cross-sectional view of the sensor housing 10 taken along the transverse center line B-B. As can be seen from the figure, the cross-section of the bottom wall 1 taken along this transverse center line is a second arched cross-section 1b having a second radius of curvature R2.

[0038] In the above embodiment, the first radius of curvature R1 is greater than the second radius of curvature R2, and the bottom wall 1 has a convex upper surface 11 and a concave lower surface 12, wherein the accommodation chamber 3 for the printed circuit board is defined by the convex upper surface 11 and the circumferential side wall 2. The circumferential side wall 2 of the sensor housing 10 defines an upper edge 21 (which can also be referred to as the upper peripheral edge) and a lower edge 22 (which can also be referred to as the lower peripheral edge). Advantageously, the bottom wall 1 is configured such that its outer peripheral edge 12 is substantially flush with the lower edge 22 of the circumferential side wall 2, so that the size of the sensor housing 10 can be limited within a relatively small range, and the above bottom wall structure can be designed within the space range of the existing housing of the traditional design without requiring additional space, thereby providing a sensor with a smaller size. Moreover, this connection manner between the special-shaped arched bottom wall and the circumferential side wall enables the sensor housing 10 to better resist the ability of high-temperature deformation. Compared with the traditional design, the deformation amount at high temperature can be reduced by, for example, 15%.

[0039] In the process of forming the bottom wall 1 with an arched cross-section, the arc surfaces with the first radius of curvature R1 and the second radius of curvature R2 can be generated by the three-point circle method. Under the condition that the height and length of the cross-section are uniquely determined, the circular arc is also uniquely determined. Specifically, the first radius of curvature R1 and the second radius of curvature R2 can be defined by the following relational expressions:

[0040] R1 = L / sin(180° - 2arctan(L / H));

[0041] R2 = W / sin(180° - 2arctan(W / H));

[0042] wherein, L is the length of the bottom wall, W is the width of the bottom wall, and H is the vertical distance between the center point of the concave lower surface 12 and the plane where the outer peripheral edge 13 of the bottom wall 1 is located (see Figure 4 ).

[0043] Figure 5AAn embodiment of the bottom wall 1 of the sensor housing 10 is shown. In this embodiment, the bottom wall 1 is configured as a first arc section 101, a second arc section 102, a third arc section 103, and a fourth arc section 104. The first arc section 101 and the second arc section 102 are opposite to each other in the length direction of the bottom wall 1 and have the same first radius of curvature R1; moreover, the first arc section 101 and the second arc section 102 are symmetric about the transverse center line B-B. The third arc section 103 and the fourth arc section 104 are opposite to each other in the width direction of the bottom wall 1 and have the same second radius of curvature R2; the third arc section 103 and the fourth arc section 104 are symmetric about the longitudinal center line A-A. Optionally, a rectangular planar section 106 may also be provided at the central position of the bottom wall 1, and this rectangular planar section is located between the first arc section and the second arc section and between the third arc section and the fourth arc section.

[0044] Figure 5B Another embodiment of the bottom wall 1 of the sensor housing 10 is shown. In this embodiment, in order to avoid stress concentration, preferably, there are fillet transition portions 105 between the first arc section 101 and the adjacent third arc section 103, between the first arc section 101 and the adjacent fourth arc section 104, between the second arc section 102 and the adjacent third arc section 103, and between the second arc section 102 and the adjacent fourth arc section 104.

[0045] Refer to again Figure 3 and Figure 4 , the sensor housing 10 further has four support columns 14 extending from the convex upper surface 11 of the bottom wall 1, and the top surfaces of these support columns are preferably located in the same plane. The printed circuit board can be fixedly installed in the accommodation chamber 3 through these support columns, that is, fixedly connected to the sensor housing 10. The sensor housing 10 further includes a first reinforcing rib 110 extending outward from the convex upper surface 11 and a second reinforcing rib 120 extending outward from the concave lower surface 12. Both the first reinforcing rib 110 and the second reinforcing rib 120 are grid-shaped reinforcing ribs connected to the circumferential side wall 2.

[0046] Figure 6 is a cross-sectional view of an embodiment of a sensor according to the present invention, such as a position sensor 100, showing the printed circuit board 200 installed in the sensor housing 10. Before installing the printed circuit board 200, the support columns 14 are cylindrical. During the installation process, the support columns pass through the holes in the printed circuit board to position it, and then the part of the support column above the printed circuit board 200 is heated and melted by a hot air riveting process to form a rotating body structure 14a (similar to a mushroom head), so as to fixedly install the printed circuit board 200 to the sensor housing 10.

[0047] In one embodiment, such a position sensor can be a non-contact position sensor. However, it should be understood that the sensor housing 10 according to the present utility model is not limited to such a sensor and can be applied to any housing design with a requirement for high-temperature deformation resistance. This sensor housing structurally protects the deformation of the PCB installation area. Compared with traditional sensor housings, the deformation of the sensor housing according to the present application in the PCB installation area is significantly reduced.

[0048] Figure 7 Fig. 5 shows a schematic structural view of a sensor 10 according to the present utility model, in particular a non-contact position sensor cooperating with a target block 300 on the client side. For a non-contact position sensor, a printed circuit board 200 is installed inside the sensor housing 10 to detect the movement of the target block (on the client side) to achieve the functions of the sensor, such as detecting gear changes or detecting the rotational speed of a motor shaft. The key feature is the detection distance between the printed circuit board 200 and the target block 300. However, thermal deformation can have a very large impact on the detection distance, thereby affecting the accuracy of the sensor.

[0049] Figure 8A Fig. 9 shows a comparison of the thermal deformation amounts of a sensor housing with a traditional design and a sensor housing according to an embodiment of the present utility model at different temperatures in the finite element analysis results. It can be seen from the figure that the maximum thermal deformation amount of the sensor housing according to the present utility model at 140 °C is approximately 0.26 mm, while the maximum thermal deformation amount of the sensor housing with a traditional design at 140 °C is approximately 0.34 mm, and the deformation area of the sensor housing with a traditional design is distributed in the PCB installation area (i.e., the area where the support columns are located), while the main distribution area of the deformation of the sensor housing according to the present utility model is not in the PCB installation area. Thus, the sensor housing 10 according to the present utility model structurally protects the thermal deformation of the PCB installation area.

[0050] Figure 8B Fig. 13 shows a comparison between the thermal deformation amount of the induction area of the PCB fixed to a sensor housing with a traditional design and the thermal deformation amount of the induction area of the PCB fixed to a sensor housing according to an embodiment of the present utility model in the finite element analysis results. It can be seen from the figure that the maximum deformation amount of the PCB fixed to the sensor housing according to the present utility model at 140 °C is 0.163 mm, while the maximum deformation amount of the PCB fixed to the sensor housing with a traditional design at 140 °C is 0.193 mm, and the sensor housing of the present application reduces the thermal deformation amount by approximately 15.5%.

[0051] However, those skilled in the art should understand that the degree of reduction in the above-mentioned thermal deformation is merely illustrative. The reduction in thermal deformation of the position sensor using the sensor housing according to the present application is the result obtained by testing in a working environment where the sensor housing is not subjected to additional forces. Specifically, such a working environment means that the sensor housing and the motor of the client form an assembly unit and are together in a chamber, and the chamber can adjust its own pressure to be the same as the external environment (for example, through a pressure relief valve). Therefore, there is no pressure difference between the internal chamber and the external environment in a high-temperature environment, and the sensor housing is not subjected to additional forces.

[0052] However, in other working environments, for example, when the sensor works in a sealed chamber, if the temperature rises in this case, the pressure in the sealed chamber is greater than the pressure of the external environment, resulting in the sensor housing being greatly expanded due to the force of the pressure difference. Thus, the thermal deformation amount of the sensor housing according to the present utility model will be further reduced. For example, the thermal deformation amount can be reduced by about 20%.

[0053] For those skilled in the art, various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of the present utility model. Based on the practice of the present utility model disclosed in this specification, other embodiments of the present utility model will be obvious to those skilled in the art. This specification and the examples disclosed therein should be considered merely illustrative, and the true scope of the present utility model is specified by the appended claims and their equivalents.

Claims

1. A sensor housing, the sensor housing (10) comprising a bottom wall (1) and a circumferential side wall (2) extending vertically from the outer periphery of the bottom wall, characterized in that: The bottom wall (1) has a longitudinal center line along its length direction and a transverse center line along its width direction, and its projection on a horizontal plane is a rectangle; The cross section of the bottom wall (1) taken along the longitudinal center line is a first arched cross section (1a) having a first radius of curvature (R1), and the cross section of the bottom wall taken along the transverse center line is a second arched cross section (1b) having a second radius of curvature (R2), wherein the first radius of curvature is greater than the second radius of curvature; and The bottom wall has a convex upper surface (11) and a concave lower surface (12), wherein a receiving chamber (3) for a printed circuit board is defined by the convex upper surface (11) and the circumferential side wall (2).

2. The sensor housing according to claim 1, characterized in that The circumferential side wall (2) has an upper edge (21) and a lower edge (22), and the outer peripheral edge (13) of the bottom wall (1) is located in the same plane and is flush with the lower edge (22).

3. The sensor housing according to claim 2, characterized in that: The first radius of curvature (R1) and the second radius of curvature (R2) are defined by the following relationship: R1=L / sin(180°-2arctan(L / H)); R2=W / sin(180°-2arctan(W / H)); Wherein, L is the length of the bottom wall, W is the width of the bottom wall, and H is the vertical distance between the center point of the concave lower surface (12) and the plane where the outer peripheral edge (13) of the bottom wall (1) is located.

4. The sensor housing according to any one of claims 1 to 3, characterized in that The bottom wall (1) comprises a first arc segment (101) and a second arc segment (102) having a first radius of curvature, and a third arc segment (103) and a fourth arc segment (104) having a second radius of curvature, wherein the first arc segment and the second arc segment are opposite to each other in the length direction of the bottom wall, and the third arc segment and the fourth arc segment are opposite to each other in the width direction of the bottom wall.

5. The sensor housing according to claim 4, characterized in that: There is a rounded transition portion (105) between the first arc segment and the third arc segment, between the first arc segment and the fourth arc segment, between the second arc segment and the third arc segment, and between the second arc segment and the fourth arc segment.

6. The sensor housing according to claim 4, characterized in that A rectangular planar section (106) is provided at the center of the bottom wall (1), and is located between the first arc-shaped section and the second arc-shaped section and between the third arc-shaped section and the fourth arc-shaped section.

7. The sensor housing according to any one of claims 1 to 3, characterized in that The sensor housing also has a plurality of support columns (14) extending from the convex upper surface (11) of the bottom wall, and the printed circuit board is fixedly mounted in the accommodating chamber (3) via the plurality of support columns.

8. The sensor housing according to any one of claims 1 to 3, characterized in that The sensor housing further comprises a first reinforcing rib (110) extending outward from the convex upper surface (11) and a second reinforcing rib (120) extending outward from the concave lower surface (12).

9. A sensor, characterized in that: The sensor (100) comprises a sensor housing (10) according to any one of claims 1 to 8 and a printed circuit board (200) arranged in the sensor housing.

10. The sensor according to claim 9, characterized in that The sensor (100) is a non-contact position sensor.

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