CN118010238A - High waterproof low pressure sensor - Google Patents

Abstract

The invention provides a high-waterproof low-pressure sensor, which comprises a shell, wherein one end of the shell is provided with a mounting end for inflow of a medium, the other end of the shell is provided with an opening cavity, a pressure sensing element and a circuit board are arranged in the opening cavity, a sensing surface of the pressure sensing element faces the mounting end, the mounting end is provided with a medium channel for the medium to flow to the sensing surface, the end surface of the opening cavity facing the sensing surface is provided with an inner sealing element, the inner sealing element surrounds the medium channel, the opening cavity is also internally provided with a gland for pressing the pressure sensing element to the inner sealing element, the circuit board is placed on the pressure sensing element, the pressure sensing element is electrically connected with the circuit board, the gland is provided with a contact pin, one end of the contact pin is electrically connected with the circuit board, the other end of the contact pin is electrically connected with an external connector through a wire, one side of the gland, which is far away from the pressure sensing element, is provided with a pouring sealant for sealing the opening cavity, and a welding point of the contact pin and the wire is positioned in the pouring sealant.

Description

High waterproof low pressure sensor

Technical Field

The invention relates to the technical field of pressure sensors, in particular to a high-waterproof low-pressure sensor.

Background

Sensor technology is one of the important technologies of modern measurement and automation systems, and almost every technology is independent of the sensor from process control of production to modern technological life. The ceramic capacitive pressure sensor is a common pressure sensor type, has wide pressure range and wide application field, is widely applied to the fields of automobiles, household appliances, industries and the like, has similar basic structures of products in different pressure ranges, is mainly formed by welding and riveting combination of pressure sensing elements, circuit boards, electric connectors, metal shells and the like, has similar production processes, has no obvious difference in structure of high-low pressure products, and is mainly formed by adjusting the structure and the materials of pressure-bearing members, so that the cost of the high-low pressure products has no obvious difference. And when the pressure-sensitive thin sheet is used in a low-pressure (< 1 MPa) environment, the pressure-sensitive thin sheet is thinner, the sensitivity is higher, the pressure-sensitive thin sheet is easily influenced by assembly stress, the manufacturing process is difficult, and the product precision is difficult to reach the required conditions. Therefore, it is necessary to design a ceramic core type pressure sensor suitable for use in a low pressure environment, and to change the structure of the existing low pressure sensor, so as to reduce the flow of manufacturing procedures, reduce the production cost, and meet the severe waterproof requirement.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a high-waterproof low-pressure sensor, which at least solves part of the problems in the prior art.

The invention is realized in the following way:

The invention provides a high-waterproof low-pressure sensor, which comprises a shell, wherein one end of the shell is provided with a mounting end for inflow of a medium, the other end of the shell is provided with an opening cavity, a pressure sensing element and a circuit board are arranged in the opening cavity, the sensing surface of the pressure sensing element faces towards the mounting end, the mounting end is provided with a medium channel for the medium to flow towards the sensing surface, the end face of the opening cavity facing towards the sensing surface is provided with an inner sealing element, the inner sealing element surrounds the medium channel, the opening cavity is also internally provided with a gland for pressing the pressure sensing element towards the inner sealing element, the circuit board is arranged on the pressure sensing element, the pressure sensing element is electrically connected with the circuit board, the gland is provided with a contact pin, one end of the contact pin is electrically connected with the circuit board, the other end of the contact pin is electrically connected with an external connector through a wire, one side of the gland far away from the pressure sensing element is provided with a glue for sealing the opening cavity, and the welding point of the contact pin and the wire is positioned in the pouring sealant.

Further, a first groove is formed in one side, far away from the pressure sensing element, of the gland, the contact pin is arranged in the first groove, and the welding point of the contact pin and the wire is located in the first groove.

Further, a containing cavity for containing the circuit board is formed in one side, facing the pressure sensing element, of the gland.

Further, the gland is in snap connection with the inner wall of the shell.

Further, the outer wall of the gland is annularly provided with a protruding block, and the inner wall of the shell is provided with a second groove which is matched and clamped with the protruding block.

Further, the inner wall of the shell is provided with a limit step, and the step surface of the limit step is flush with the surface of the pressure sensing element facing the gland.

Further, the installation end is the step shaft structure, including major diameter section and minor diameter section, the major diameter section is close to the opening cavity sets up, the minor diameter section stretches into in the external connection end, be equipped with the external screw thread that is used for the installation on the minor diameter section, the terminal surface that the major diameter section is close to the minor diameter section and the terminal surface butt of external connection end, the medium passageway is followed minor diameter section extends to the major diameter section, the major diameter section has seted up the third recess on the terminal surface that is close to the minor diameter section, be equipped with outside sealing member in the third recess, the terminal surface butt of outside sealing member and external connection end, outside sealing member encircles the minor diameter section sets up.

Further, the inner seal and the outer seal are both annular rubber seals.

Further, the shell and the gland are both made of plastic materials.

Further, the shell and the gland are integrally formed through injection molding.

The invention has the following beneficial effects:

1. the invention provides the pressure sensor which is used in a low-pressure environment, is efficient and waterproof and can greatly reduce the cost.

2. In the invention, the shell is made of plastic materials and is injection molded, so that the cost is low compared with the metal shell, the production efficiency is greatly improved, and the purchasing period is shortened.

3. The high-waterproof low-pressure sensor provided by the invention greatly reduces production procedures, does not need procedures such as pre-assembly, riveting, gluing, dispensing and the like, and can directly position key parts by the gland, so that the assembly efficiency is improved, and the cost is reduced.

4. In the invention, the sensing piece in the pressure sensing element is only contacted with the inner sealing piece, and the inner sealing piece is made of rubber material, so that larger stress can not be generated on the sensing piece, the stress influence of the external environment on the pressure sensing element is reduced, the precision of a product is improved, and the use requirement of a low-pressure environment is met.

5. According to the invention, the pouring sealant fills the open cavity of the shell, wraps up the parts inside the shell, prevents the parts from being corroded by external media, ensures the stability of the product, and can be highly waterproof, and the external water and other media cannot overflow into the product; the pouring sealant has good fluidity in the filling process, can fill all gaps of the opening cavity of the shell, is solidified under the high-temperature condition after the pouring sealant is filled in the cavity of the opening of the shell, has enough strength and temperature resistance, can effectively prevent water and dust, improves the stability of the product, and is suitable for various severe environments.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is an exploded view of a high waterproof low pressure sensor provided by an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a high water resistance low pressure sensor provided by an embodiment of the present invention;

FIG. 3 is a schematic view of a housing according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a gland according to an embodiment of the present invention.

In the figure: 1-a housing; 2-an external seal; 3-an inner seal; 4-a pressure sensing element; 5-a circuit board; 6-capping; 7-pouring sealant; 8-conducting wires; a 9-connector; 10-medium channel; 11-a first groove; 12-limiting steps; 13-large diameter section; 14-a small diameter section; 15-an open cavity; 16-bump.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.

As shown in fig. 1-4, the embodiment of the invention provides a high waterproof low pressure sensor, which comprises a housing 1, wherein one end of the housing 1 is provided with a mounting end (the medium is gas or liquid) for inflow of the medium, the other end of the housing 1 is provided with an opening cavity 15, the opening cavity 15 is internally provided with a pressure sensing element 4 and a circuit board 5, the sensing surface of the pressure sensing element 4 faces towards the mounting end, the mounting end is provided with a medium channel 10 for the medium to flow towards the sensing surface, the end surface of the opening cavity 15 facing towards the sensing surface is provided with an inner sealing member 3, the inner sealing member 3 surrounds the medium channel 10, the opening cavity 15 is internally provided with a gland 6 for pressing the pressure sensing element 4 towards the inner sealing member 3, the circuit board 5 is placed on the pressure sensing element 4, the pressure sensing element 4 is electrically connected with the circuit board 5, one end of the contact pin is electrically connected with the circuit board, the other end of the contact pin is electrically connected with an external connector 9 through a wire 8, one side of the pressure sensing element 4 is provided with a sealing cap 7 far away from the opening 7 of the sealing member, and the sealing cap 7 is arranged in the sealing cap 7. An installation groove for installing the inner sealing element 3 can be arranged on the end face of the opening cavity 15 facing the induction surface so as to limit the inner sealing element 3; the inner seal 3 allows an isolated medium channel between the housing 1 and the pressure sensitive element 4, avoiding medium flowing up to the electronics part.

As shown in fig. 4, a first groove 11 is formed in one side, far away from the pressure sensing element 4, of the gland 6, the contact pin is arranged in the first groove 11, the welding point of the contact pin and the wire 8 is located in the first groove 11, and the depth of the wire covered by the pouring sealant is increased in the glue pouring process, so that the overall height is reduced, and meanwhile, the water resistance is improved. As shown in fig. 2, a receiving cavity for receiving the circuit board 5 is formed on a side of the gland 6 facing the pressure sensing element 4.

The gland 6 is in snap connection with the inner wall of the shell 1. As shown in fig. 2, the outer wall of the gland 6 is provided with a bump 16 (the cross section of the bump 16 in the vertical direction is trapezoidal), and the inner wall of the housing 1 is provided with a second groove which is in fit and clamping connection with the bump 16. As shown in fig. 2, the inner wall of the housing 1 is provided with a limit step 12, and the step surface of the limit step 12 is flush with the surface of the pressure sensing element 4 facing the gland 6. The limiting step 12 is designed in the shell 1, so that the gland 6 can be prevented from being pressed downwards in the assembly process, and the damage to the inner sealing element 3 caused by the overpressure is avoided, and the service life is prevented from being influenced.

As shown in fig. 2, the installation end is of a stepped shaft structure and comprises a large diameter section 13 and a small diameter section 14, the large diameter section 13 is close to the opening cavity 15, the small diameter section 14 stretches into the external connection end, an external thread for installation is arranged on the small diameter section 14, the end face of the large diameter section 13 close to the small diameter section 14 is in butt joint with the end face of the external connection end, the medium channel 10 extends from the small diameter section 13 to the large diameter section 14, a third groove is formed in the end face of the large diameter section close to the small diameter section, an external sealing element 2 is arranged in the third groove, the external sealing element 2 is in butt joint with the end face of the external connection end, and the external sealing element 2 is arranged around the small diameter section. The low pressure sensor is mounted on an external connecting end, the external connecting end is provided with an internal thread matched with the external thread of the small diameter section 14, and after the external thread is screwed, the end face of the large diameter section 13, which is close to the small diameter section 14, and the end face of the external sealing element 2 are abutted with the end face of the external connecting end. The outer seal 2 prevents loss due to medium spillage in the outer connection. As shown in fig. 1, the inner seal 3 and the outer seal 2 are both annular rubber seals.

In this embodiment, the housing 1 and the gland 6 are both made of plastic. The contact pin is injection molded on the gland 6. The shell 1 and the gland 6 are integrally formed by injection molding. The connection end (external connection end) between the housing 1 and the customer is not limited to threaded connection, and other connection modes such as snap spring connection can be adopted.

The invention provides a high-waterproof low-pressure sensor which is not only suitable for environments with smaller pressure (less than 1 MPa), but also can meet the waterproof requirement of increasingly high standards, reduce the manufacturing and assembly process flow and greatly reduce the production cost.

As shown in fig. 1-2, one end of the housing 1 is a tubular structure, the tubular structure is mechanically matched with the outside, and the tubular structure is tightly matched with the external threaded connection to form a fixation. The lower end face of the outer side of the tubular structure of the shell 1 is provided with a protruding structure, an outer sealing piece 2 is arranged on the inner side of the protruding structure, the height of the protruding structure controls the compression amount of the outer sealing piece, and the outer sealing piece 2 is matched with an outer port to form a seal, so that medium overflow loss is prevented. The other end of the shell 1 is an open cavity, and the inner sealing piece 3, the pressure sensing element 4, the circuit board 5 and the gland 6 are arranged in the open cavity. The pressure sensing element 4 is arranged on the inner sealing element 3, the pressure sensing element 4 is composed of a substrate and a sensing piece, the sensing piece is thinner, and can sense pressure change to generate deformation, and pressure signals are transmitted. The thickness of the sensing piece is thin enough to sense the slight pressure change in the low pressure environment. The circuit board 5 is arranged on the pressure sensing element 4, 3 small round holes are designed at one end of the circuit board 5 and correspond to the positions of 3 PIN needles on the pressure sensing element 4, the 3 PIN needles are electrically connected with a circuit on the circuit board 5 in a brazing mode, meanwhile, 3 small round holes are also designed at the other end of the circuit board 5 and are coupled (electrically connected) with a contact PIN on the gland 6 in a brazing mode, and pressure signals are transmitted. The contact pin on the gland 6 is electrically connected with the lead 8, and the connector 9 at the other end of the lead 8 can be directly connected with the client through an electric signal to transmit signals. In this embodiment, the circuit board 5 is folded into an upper layer and a lower layer, the lower layer is closely attached to the pressure sensing element 4, and the upper layer is closely attached to the inner wall of the pressing cover 6. The gland 6 is fixed with the shell 1 in a buckling manner, the pressure sensing element 4 is fixed, meanwhile, the gland 6 downwards presses the pressure sensing element 4 to enable the pressure sensing element to generate certain extrusion on the inner sealing element 3, sealing force is formed, and the flow of a medium in the product is limited. The pouring sealant 7 fills the open cavity of the shell 1, the parts inside the shell 1 are wrapped, the parts are prevented from being corroded by external media, the stability of the product is guaranteed, meanwhile, the pouring sealant 7 can be highly waterproof, the media such as external water cannot overflow and infiltrate into the product, the pouring sealant 7 has good fluidity in the filling process, gaps in the open cavity of the shell can be filled, the pouring sealant 7 is solidified under the high temperature condition after filling the open cavity of the shell 1, the solidified pouring sealant 7 has enough strength and temperature resistance, the water and dust can be effectively prevented, the stability of the product can be improved, and the product is applicable to various severe environments.

As shown in fig. 3, the casing 1 is screwed to the external connection end, and as the casing 1 is screwed, the external sealing element 2 in the protruding structure is gradually compressed until the protruding bottom surface coincides with the plane of the external connection end, and at this time, the external sealing element 2 reaches a predetermined optimal contraction amount, so as to form an axial sealing structure. The main bearing end of the sealing structure is positioned at the sensor shell end, and the client can uniformly adopt plane matching, so that the sensor can be applied to more working conditions and fields, the process of designing a sealing groove is omitted by the client, and the sealing effect is controllable. The shell 1 is made of a plastic material with certain mechanical strength and high temperature resistance, is molded in an injection molding mode, can be used without machining after molding, can be produced in a large scale in a short time, and reduces the purchasing period and cost.

As shown in fig. 1-2, the circuit board 5 is in a 8-shaped structure, after the circuit board 5 is bent into an upper layer and a lower layer, three through holes are designed in the lower layer to be matched with PIN needles of the pressure sensing element 4, through holes convenient to braze with the gland 6 are designed in the upper layer of the circuit board 5, bonding pads on the through holes cannot be too large, the circuit and other electronic components on the circuit board are prevented from being influenced by too large bonding points, the circuit board 5 has certain toughness, and certain bending and deformation can be realized in the assembling process without breaking risk, so that the assembling stability is improved.

As shown in fig. 4, the gland 6 is in a circular ring structure, the trapezoid protruding structure on the outer side can be matched with the groove on the inner side of the shell 1 to form a buckle fixing structure, the gland 6 is directly pressed into the shell 1 in the assembling process, the limiting step 12 in the shell 1 can limit the downward movement of the gland 6 to prevent the gland 6 from transitionally pressing down to damage the inner sealing element 3, the gland 6 is made of a plastic material with certain strength and high temperature resistance, and is molded in an injection molding mode, and the molded plastic material can be used without machining after molding, so that the production is convenient and quick. The gland 6 is provided with a pin structure penetrating through the plastic part, the lower end of the pin is connected with the circuit board 5, the upper end of the pin is connected with the lead 8, and signals are transmitted to the connector 9, so that the signals are perceived by a client. The upper end face of the gland 6 is provided with a groove structure, the contact pin is connected with the lead 8 in the groove, the height of the wrapping layer of the pouring sealant 7 on the welding part of the lead 8 and the contact pin can be increased on the premise that the whole height of a product is not increased, the protection level is improved, and the reliability of the product is enhanced.

What is not described in detail in this specification is prior art known to those skilled in the art.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.

Claims (10)

1. A high waterproof low pressure sensor, characterized in that: the pressure sensing device comprises a shell, one end of the shell is provided with a mounting end for medium inflow, the other end of the shell is provided with an opening cavity, a pressure sensing element and a circuit board are arranged in the opening cavity, the sensing surface of the pressure sensing element faces the mounting end, a medium channel for medium to flow to the sensing surface is formed in the mounting end, an inner sealing element is arranged on the end face of the opening cavity, which faces the sensing surface, the inner sealing element surrounds the medium channel, a gland for pressing the pressure sensing element to the inner sealing element is further arranged in the opening cavity, the circuit board is arranged on the pressure sensing element, the pressure sensing element is electrically connected with the circuit board, a contact pin is arranged on the gland, one end of the contact pin is electrically connected with the circuit board, the other end of the contact pin is electrically connected with an external connector through a wire, one side, far away from the pressure sensing element, of the gland is provided with a pouring sealant for sealing the opening cavity, and a welding point of the contact pin and the wire is located in the pouring sealant.

2. The high water resistance low pressure sensor of claim 1, wherein: the gland is equipped with first recess in one side of keeping away from the pressure sensing component, the contact pin is installed in the first recess, the welding point of contact pin and wire is located in the first recess.

3. The high water resistance low pressure sensor of claim 1, wherein: and one side of the gland, facing the pressure sensing element, is provided with a containing cavity for containing the circuit board.

4. The high water resistance low pressure sensor of claim 1, wherein: the gland is in snap connection with the inner wall of the shell.

5. The high water resistance low pressure sensor of claim 4, wherein: the outer wall ring of gland is equipped with the lug, the inner wall of casing be equipped with the second recess of lug cooperation joint.

6. The high water resistance low pressure sensor of claim 1, wherein: the inner wall of the shell is provided with a limiting step, and the step surface of the limiting step is flush with the surface of the pressure sensing element facing the gland.

7. The high water resistance low pressure sensor of claim 1, wherein: the installation end is the step shaft structure, including major diameter section and minor diameter section, the major diameter section is close to the open cavity body sets up, the minor diameter section stretches into in the external connection end, be equipped with the external screw thread that is used for the installation on the minor diameter section, the terminal surface butt of the terminal surface that the major diameter section is close to the minor diameter section and external connection end, the medium passageway is followed minor diameter section extends to the major diameter section, the major diameter section has seted up the third recess on the terminal surface that is close to the minor diameter section, be equipped with external seal spare in the third recess, the terminal surface butt of external seal spare and external connection end, external seal spare encircles the minor diameter section sets up.

8. The high water resistance low pressure sensor of claim 7, wherein: the inner seal and the outer seal are both annular rubber seals.

9. The high water resistance low pressure sensor of claim 1, wherein: the shell and the gland are both made of plastic materials.

10. The high water resistance low pressure sensor of claim 9, wherein: the shell and the gland are integrally formed through injection molding.