Pressure sensor

Abstract

A pressure sensor comprises a housing which comprises a main housing and an upper cover arranged at one longitudinal end of the main housing, and the main housing is provided with a pressure introduction channel; the substrate is horizontally mounted in the mounting cavity and adhesively seals one end of the inner side of the pressure introduction channel, processing circuits are arranged on the surfaces of the upper side and the lower side of the substrate, and a plurality of electric contact parts electrically connected with the processing circuits are arranged on the surfaces of the upper side and the lower side of the substrate; the pressure sensitive element is fixed on the surface of one side of the substrate to receive the pressure of the pressure medium to be measured; a plurality of terminals; the element is fixed at the bottom of the mounting cavity and comprises a seat body and a plurality of spring pieces fixed on the seat body, one end of each spring piece is elastically and electrically contacted with one electric contact part, and the other end of each spring piece is elastically and electrically contacted with one end of the inner side of one terminal group. According to the invention, the plurality of spring pieces are fixed on the same element, and the terminal and the electric contact part are connected through the spring pieces, so that the connection strength between the terminal and the electric contact part is improved, and the assembly efficiency of the spring pieces can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pressure detection, and particularly relates to a pressure sensor. BACKGROUND

[0002] The pressure sensor is a sensor for measuring the pressure of an environment or medium, and is currently realized through MEMS (micro-electro-mechanical system), that is, the pressure is measured through the piezoresistive effect of semiconductor silicon. In this case, the middle part of the silicon core is provided in a diaphragm shape, and the pressure applied to the silicon diaphragm on both sides causes the resistance value of the doped resistor on the silicon diaphragm to change. The current or voltage signal output by the measurement circuit composed of several resistors can be further processed by the conditioning circuit and then output to the outside as the measurement result. When a vacuum cavity is provided on one side of the silicon chip, the measured pressure is the pressure applied on the other side relative to the vacuum, that is, the absolute pressure. When atmospheric pressure is introduced on one side of the diaphragm, the measured pressure is the pressure relative to the atmosphere, that is, the gauge pressure. When other pressures are introduced on both sides of the diaphragm, the measured pressure is the difference between the pressures on both sides, that is, the differential pressure. In some other sensors, a temperature-sensitive element can also be integrated to measure the pressure and temperature of the medium at the same time.

[0003] In the prior art, the pressure sensor usually includes a pressure interface, a shell and an electrical connector surrounding an inner cavity, a pressure-sensitive element and an electronic module assembly are arranged in the inner cavity, and the electronic module assembly and the pressure-sensitive element need to be electrically connected through a lead wire, and the electronic module assembly and the electrical connector also need to be electrically connected through a lead wire.

[0004] These lead wires are relatively fragile, especially when working for a long time under vibration conditions, the lead wires are prone to falling off, so the lead wires need to be reinforced. For example, CN118565687A discloses a pressure sensor, which uses a surrounding frame to surround the pressure-sensitive element, and covers the surrounding frame with a gel, which protects the pressure-sensitive element and also protects the lead wire between the electronic module assembly and the pressure-sensitive element through the gel. Such a protection method can only protect the lead wire between the electronic module assembly and the pressure-sensitive element, and the lead wire between the electronic module assembly and the electrical connector is still prone to falling off under long-time vibration conditions.

[0005] Therefore, in some solutions, the lead wire is replaced by a leaf spring, but the leaf spring is small, and there are multiple lead wires that need to be replaced by leaf springs, and the installation of the leaf spring is troublesome. SUMMARY

[0006] The purpose of the present application is to provide a pressure sensor to solve at least one of the above technical problems.

[0007] To achieve the above purpose, the technical solution adopted by the present application is: A pressure sensor, comprising: a housing internally formed with a mounting cavity, comprising a main housing and an upper cover arranged at a longitudinal end of the main housing, a side of the main housing away from the upper cover being provided with a pressure introduction channel for introducing a pressure medium to be measured, which is in communication with the mounting cavity; a substrate horizontally mounted in the mounting cavity and adhesively sealing an inner end of the pressure introduction channel, upper and lower side surfaces of the substrate being provided with a processing circuit and a plurality of electrical contact portions electrically connected to the processing circuit; a pressure sensitive element fixed to a side surface of the substrate to receive a pressure of the pressure medium to be measured, and electrically connected to the processing circuit; a plurality of terminals, inner ends of the terminals extending into the mounting cavity; an element fixed to a bottom of the mounting cavity, comprising a seat and a plurality of spring pieces fixed to the seat, one end of each of the spring pieces being elastically electrically connected to one of the electrical contact portions, and the other end of each of the spring pieces being elastically electrically connected to an inner end of one of the terminal groups.

[0008] Preferably, the element is internally provided with an air permeable channel for allowing ambient pressure to communicate with the mounting cavity, and an inner end of the air permeable channel is covered with a waterproof air permeable membrane.

[0009] Preferably, a lower side of the main housing is provided with a fixed hole penetrating through the main housing, and the element is downwardly clamped in the fixed hole and allows an outer end of the air permeable channel to communicate with the fixed hole.

[0010] Preferably, an inner wall of a bottom of the main housing is downwardly recessed to form a recessed cavity receiving groove defining the mounting cavity, and the element is partially received in the receiving groove.

[0011] Preferably, a periphery of the element is sealed to an inner edge of the fixed hole by a first sealant filled in the receiving groove.

[0012] Preferably, the spring piece comprises a fixed segment at least partially molded in the seat, one end of the fixed segment is integrally connected with a first abutting portion electrically abutting to the electrical contact portion, and the other end of the fixed segment is integrally connected with a second abutting portion electrically abutting to the inner end of the terminal.

[0013] Preferably, the electrical contact portion is arranged on a lower side surface of a first end of the substrate, and the first abutting portion upwardly abuts to the electrical contact portion.

[0014] Preferably, the pressure sensor further comprises a pressing element downwardly pressing the first end of the substrate, the pressing element being integrally connected to the seat or integrally connected to the upper cover.

[0015] Preferably, one end of the fixed section is bent upwards to form a first rising section outside the seat body, the first rising section is bent downwards away from one end of the fixed section to form the first abutting part, the first abutting part is electrically contacted to the electric contact part upwards; one end of the fixed section away from the first rising section is bent upwards to form a second rising section outside the seat body, the second rising section is bent downwards away from one end of the fixed section to form a descending section, one end of the descending section away from the second rising section is bent upwards to form the second abutting part, the second abutting part is electrically contacted to the terminal upper part downwards.

[0016] Preferably, the electric contact part is arranged on the upper surface of the first end of the substrate; the first abutting part is abutted to the electric contact part downwards; the pressure sensor further comprises a pressing element which presses the first end of the substrate upwards, the pressing element is integrally connected to the seat body.

[0017] Compared with the prior art, the present application has the following advantages: (1) The present application fixes multiple spring sheets to the same element, connects the terminal and the electric contact part by the spring sheets, improves the connection strength between the terminal and the electric contact part, and accelerates the assembly efficiency of the spring sheets.

[0018] (2) The first connecting arm and the first hook body arranged on the element are used to fix the element and the bottom of the accommodating groove, the element fixing method is simple and fast, and the position of the spring sheet on the element can be fixed, thereby improving the stability of the electrical connection between the terminal and the electric contact part. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a structure schematic view of the pressure sensor of the first embodiment; Figure 2 It is a structure schematic view of the pressure sensor of the second embodiment; Figure 1 It is an enlarged view of the partial A shown in the figure; Figure 3 It is a structure schematic view of the pressure sensor of the second embodiment; In the figure: 1, installation cavity; 2, shell; 21, main shell; 211, end knob; 212, partition; 213, terminal; 22, upper cover; 23, sealing groove; 3, pressure introduction channel; 4, base plate; 40, pressure via; 41, electrical contact; 5, pressure sensitive element; 51, frame; 52, protective gel; 6, element; 60, seat; 61, communication hole; 7, spring piece; 71, fixed section; 72, first rising section; 73, first abutment; 74, second rising section; 75, descending section; 76, second abutment; 8, fixing hole; 9, first connecting arm; 91, first hook body; 10, second connecting arm; 101, second hook body; 11, compression element; 12, first sealing gel; 13, waterproof and breathable membrane; 14, second sealing gel; 15, accommodating groove. DETAILED DESCRIPTION

[0020] The technical solutions of the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] As shown in Figure 1 and Figure 2 , the present embodiment provides a pressure sensor, comprising: a shell 2, a base plate 4 and a pressure sensitive element 5.

[0022] The shell 2 has an installation cavity 1 inside. The shell 2 comprises a main shell 212 and an upper cover 22 arranged at one longitudinal end of the main shell 212. The outer wall of the main shell 212 is connected with an end knob 211 at one side. The end knob 211 is provided with a plurality of terminals 213. The inner side of the terminals 213 extends horizontally into the installation cavity 1 after penetrating into the main shell 21. The side of the main shell 212 away from the upper cover 22 is provided with a pressure introduction channel 3 communicating with the installation cavity 1. The pressure introduction channel 3 is defined by at least a part of the inner cavity of a pressure interface pipe 30 integrally connected to the lower side of the main shell 21. The upper side of the main shell 21 is formed with an open cavity (not labeled). The open cavity partially defines the installation cavity 1. The upper end of the open cavity has an opening. The upper cover 22 is closed to the opening of the upper end of the open cavity. The pressure introduction channel 3 is used to introduce the external pressure medium to be measured into the shell 2. In order to realize the sealing between the upper cover 22 and the main shell 21, the connection between the upper cover 22 and the main shell 21 is filled with a second sealing gel 14 to seal the upper cover 22 and the main shell 212. The second sealing gel 14 can be filled in a sealing groove 23 arranged on the main shell 21. The sealing groove 23 is arranged at the periphery of the opening of the upper end of the open cavity. The inner side of the terminals 213 can extend horizontally. The edge of the upper cover 22 can extend downward to form a sealing flange extending into the sealing groove 23.

[0023] The substrate 4 is horizontally attached to a mounting surface of the bottom of the open cavity to close the inner side of the pressure introduction channel 3, and the upper side surface of the substrate 4 is provided with a processing circuit, and the lower side surface is provided with a plurality of electrical contact portions 41 electrically connected to the processing circuit. The electrical contact portions 41 are arranged at the first end (i.e. the right end shown in FIG. 2) of the substrate 4, and the first end of the substrate 4 protrudes from the mounting surface. The processing circuit includes a conditioning chip and other electronic components. Preferably, the substrate 4 can be made of a ceramic plate, an aluminum plate, or a stainless steel plate, or a plate made of other materials with a small difference in CTE (coefficient of thermal expansion) with semiconductor materials, so as to reduce the risk of low CTE mismatch. The processing circuit is used to convert the pressure signal sensed by the pressure sensitive element 5 into an electrical signal and transmit it to an external device through the terminal 213. Figure 1

[0024] The substrate 4 can be provided with a pressure through hole 40, and the pressure sensitive element 5 is sealingly plugged into the upper side of the pressure through hole 40 and electrically connected to the processing circuit, so as to receive the pressure of the pressure medium to be measured and convert the pressure into an electrical signal, and then transmit it to the processing circuit.

[0025] The pressure sensitive element 5 described above can be preferably a piezoresistive semiconductor pressure chip, and in other embodiments, the pressure sensitive element 5 can also be other types of pressure sensitive elements 5, such as a capacitive semiconductor pressure chip, or a metal diaphragm type pressure sensitive element 5 or other suitable pressure sensitive elements 5.

[0026] The lower side of the main housing 21 can be provided with a receiving groove 15, and the receiving groove 15 can be provided with an element 6. The element 6 can include a seat body 60 (not labeled) and a plurality of spring sheets 7 fixed to the seat body 60. One end of the spring sheet 7 abuts the corresponding terminal 213 to form an electrical contact, and the other end abuts the corresponding electrical contact portion 41 to form an electrical contact, so as to form an electrical connection between the terminal 213 and the corresponding electrical contact portion 41. The electrical contact portion 41 is electrically connected to the processing circuit, and the spring sheet 7 is arranged to cooperate with the electrical contact portion 41 to form an electrical connection between the terminal 213 and the processing circuit. The plurality of spring sheets 7 described above can be arranged side by side.

[0027] In other embodiments, the processing circuit can also be alternatively arranged on the lower side surface of the substrate 4, and at this time the pressure sensitive element 5 can be directly arranged on the lower side surface of the substrate 4 and directly exposed to the pressure introduction channel 3 to receive the pressure of the pressure medium to be measured, and at this time the pressure through hole 40 on the substrate 4 can be omitted.

[0028] The pressure sensor described above uses the spring sheet 7 to connect the terminal 213 and the electrical contact portion 41 by fixing the plurality of spring sheets 7 to the seat body 60, which not only improves the connection strength between the terminal 213 and the electrical contact portion 41, but also accelerates the assembly efficiency of the spring sheet 7.​

[0029] In order to enable the spring sheet 7 to form elastic electrical contact with the terminal 213 and the electrical contact portion 41 for assembly, specifically: the spring sheet 7 can include a fixed section 71 embedded in the seat body 60. One end of the fixed section 71 can be bent upward to form a first rising section 72, the first rising section 72 is bent downward away from one end of the fixed section 71 to form a first abutting portion 73, so that the first abutting portion 73 abuts the electrical contact portion 41, the fixed section 71 is bent upward away from one end of the first rising section 72 to form a second rising section 74, the second rising section 74 is bent downward away from one end of the fixed section 71 to form a descending section 75, the descending section 75 is bent upward away from one end of the second rising section 74 to form a second abutting portion 76, so that the second abutting portion 76 abuts the upper portion of the terminal 213. In this embodiment, the spring sheet 7 is provided on the seat body 60 by bending the spring sheet 7 multiple times to form the first abutting portion 73 and the second abutting portion 76. Most of the seat body 60 can be arranged below the substrate 4 and between the substrate 4 and the terminal 213. The first abutting portion 73 abuts the electrical contact portion 41 on the bottom surface of the substrate 4, which can form good electrical contact between the spring sheet 7 and the electrical contact portion 41, and can save the material of the spring sheet 7. The second abutting portion 76 abuts the upper portion of the terminal 213 from above the terminal 213, which facilitates the installation of the element 6 and avoids the terminal 213 from interfering with the spring sheet 7. Preferably, the end of the rising section 72 away from the seat body 60 can be arranged upwardly inclined relative to the end close to the seat body 60, and the end of the first abutting portion 73 away from the seat body 60 is integrally connected to the upper end of the rising section 72. In this way, the seat body 60 can be installed in the accommodating groove 15 after the substrate 4 is installed. At this time, the rising section 72 can conveniently pass downward to the lower side of the substrate 4 by elastic deformation during installation.

[0030] In order to firmly fix the spring sheet 7 on the seat body 60, preferably, at least a part of the fixed section 71 is molded on the seat body 60, the end of the fixed section 71 away from the second rising section 74 extends out of the seat body 60, and the end of the second rising section 74 close to the fixed section 71 is molded in the seat body 60 and the other end extends out of the seat body 60. In order to fix the seat body 60 in the accommodating groove 15, preferably, a through fixing hole 8 is formed in the bottom of the accommodating groove 15, and the bottom of the seat body 60 can be provided with at least two buckles which are clamped in the fixing hole. For example, the buckle includes a first connecting arm 9 which passes through the fixing hole 8 and extends out of the main housing 212, and the end of the first connecting arm 9 outside the seat body 60 is provided with a first hook body 91 which hooks the outer wall of the main housing 212 to fix the seat body 60 and the accommodating groove 15. After the seat body 60 is fixed in the accommodating groove 15, the spring sheet 7 molded on the seat body 60 is also fixed, which is conducive to improving the stability of the electrical connection between the spring sheet 7 and the electrical contact portion 41 and the terminal 213.

[0031] To avoid the substrate 4 being pushed up from the bottom when the spring piece 7 abuts against the electrical contact 41 from the bottom of the substrate 4, and the substrate 4 is usually fixed in the mounting cavity 1 by adhesion, the substrate 4 can be pushed up under the long-time abutting of the spring piece 7, to solve this problem, preferably, a pressing element (not labeled) can be fixed on the seat body 60, the pressing element can include a second connecting arm 10 extending upward and downward, and a second hook body 101 integrally connected to the second connecting arm 10 at the end away from the seat body 60, the second hook body 101 presses the top surface of the substrate 4 close to the first end of the spring piece 7 downward. By setting the second structure, the upper surface of the substrate 4 is pressed, so that at least to a certain extent, the force of the spring piece 7 abutting from the bottom to the top of the substrate 4 can be offset. In some alternative embodiments, the electrical contact 41 can be arranged on the lower surface of the substrate 4, and the pressing element can press the first end of the substrate 4 from the bottom side, while the first abutting portion 73 abuts and electrically contacts the electrical contact 41 from the upper side.

[0032] In order to prevent the external water vapor from entering the mounting cavity 1 through the fixing hole 8 from the bottom surface of the seat body 60 and the containing groove 15 to corrode the sensor element, preferably, the bottom of the containing groove 15 is filled with the first sealing glue 12 to seal the seat body 60 and the bottom of the containing groove 15, so as to prevent the external water vapor from entering the containing cavity through the fixing hole 8 and the gap between the seat body 60 and the bottom surface of the containing groove 15.

[0033] Preferably, the seat body 60 can be provided with a ventilation passage to allow the ambient pressure to enter the installation cavity 1, so as to take the ambient pressure as the reference pressure to measure the relative pressure (gauge pressure) of the pressure medium to be measured relative to the ambient pressure. The ventilation passage can include a communication hole 61 to communicate the fixing hole 8 with the installation cavity 1, and the orifice of the communication hole 61 is sealed by the waterproof and breathable film 13. If the pressure sensor in the prior art is to measure the gauge pressure, a separate opening needs to be provided on the containing cavity to introduce the external atmospheric pressure into the containing cavity, so that the external atmosphere and the pressure medium to be measured are located on the two sides of the pressure sensitive element 5. In the present embodiment, the external atmosphere can enter the containing cavity through the fixing hole 8 and the communication hole 61, so as to utilize the fixing hole 8 provided for fixing the seat body 60, and the gauge pressure can be measured without the need for a separate opening. In order to prevent the external water vapor from entering the containing cavity through the fixing hole 8 and the communication hole 61, the waterproof and breathable film 13 is provided at the orifice of the communication hole 61 in the present embodiment. The waterproof and breathable film 13 allows gas to pass through and prevents water vapor from passing through. The waterproof and breathable film 13 can be fixed at the orifice of the communication hole 61 by pasting. In the present embodiment, the communication hole 61 penetrates the seat body 60 upward and downward while avoiding the spring sheet 7. The two orifices of the communication hole 61 are located on the top surface and the ground surface of the seat body 60, respectively. The orifice of the communication hole 61 located on the bottom surface of the seat body 60 is in communication with the fixing hole 8. The waterproof and breathable film 13 can be pasted at the orifice of the communication hole 61 located on the top surface of the seat body 60, i.e., the waterproof and breathable film 13 can be pasted on the top of the seat body 60.

[0034] Preferably, the substrate 4 is provided with a surrounding frame 51, the bottom surface of the surrounding frame 51 is sealingly connected with the substrate 4, the pressure sensitive element 5 is located in the surrounding frame 51, and the surrounding frame 51 is filled with protective gel 52 covering the pressure sensitive element 5. The protective gel 52 is provided for protecting the pressure sensitive element 5. The external atmosphere can transmit the pressure to the pressure sensitive element 5 through the protective gel 52, so that the pressure sensitive element 5 can still measure the gauge pressure. The surrounding frame 51 is provided to surround the pressure sensitive element 5, which facilitates covering the protective gel 52 on the pressure sensitive element 5 and can save the amount of protective gel 52.

[0035] Please refer to Figure 3 The pressure sensor of the second embodiment can integrally connect the compression element 11 to the inner side of the upper cover 22, the compression element 11 is pressed against the first end of the substrate 4 close to the spring sheet 7, and the upper surface of the substrate 4 is pressed from top to bottom by the compression element 11, so as to offset the force applied by the spring sheet 7 to the substrate 4 from below.

[0036] It should be noted that although the present application is disclosed with specific embodiments as above, the above embodiments are not intended to limit the present application, and those of ordinary skill in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application is defined by the scope of claims.

Claims

1. A pressure sensor, characterized by The application relates to a pressure sensor, comprising: a housing internally forming a mounting cavity, comprising a main housing and an upper cover arranged at a longitudinal end of the main housing, a pressure introduction channel for introducing a pressure medium to be measured being arranged at a side of the main housing away from the upper cover and being communicated with the mounting cavity; a substrate horizontally mounted in the mounting cavity and adhesively sealing an inner end of the pressure introduction channel, upper and lower side surfaces of the substrate being provided with processing circuits, and upper and lower side surfaces of the substrate being provided with a plurality of electric contact portions electrically connected with the processing circuits; a pressure sensitive element fixed to a side surface of the substrate to receive pressure of the pressure medium to be measured, and being electrically connected with the processing circuits; a plurality of terminals, inner ends of the terminals extending into the mounting cavity; an element fixed to a bottom of the mounting cavity, comprising a seat and a plurality of spring sheets fixed to the seat, one end of each of the spring sheets being elastically electrically contacted with one of the electric contact portions, and the other end of each of the spring sheets being elastically electrically contacted with an inner end of one of the terminal groups.

2. A pressure sensor as claimed in claim 1, wherein The element is internally provided with a gas permeable channel for communicating ambient pressure to the mounting cavity, and an inner end of the gas permeable channel is covered with a waterproof gas permeable film.

3. A pressure sensor as claimed in claim 2, wherein A fixing hole is arranged at a lower side of the main housing and penetrates the main housing, the element is downwardly clamped in the fixing hole and an outer end of the gas permeable channel is communicated to the fixing hole.

4. A pressure sensor as claimed in claim 3, wherein An inner wall of a bottom of the main housing is downwardly recessed to form a concave cavity accommodating groove defining the mounting cavity, and the element is partially accommodated in the accommodating groove.

5. A pressure sensor as claimed in claim 4, wherein the diaphragm is formed from a material having a coefficient of thermal expansion of less than 10 ppm / °C. An outer periphery of the element is sealed to an inner edge of the fixing hole by a first sealant filled in the accommodating groove.

6. A pressure sensor as claimed in claim 1, wherein, The spring sheet comprises a fixed section at least partially molded in the seat, one end of the fixed section is integrally connected with a first abutting portion electrically contacted with the electric contact portion, and the other end of the fixed section is integrally connected with a second abutting portion downwardly electrically contacted with the inner end of the terminal.

7. A pressure sensor as claimed in claim 6, wherein The electric contact portion is arranged at a lower side surface of a first end of the substrate, and the first abutting portion is upwardly abutted against the electric contact portion.

8. A pressure sensor as claimed in claim 7, wherein The pressure sensor further comprises a pressing element downwardly pressing the first end of the substrate, the pressing element is integrally connected with the seat or integrally connected with the upper cover.

9. A pressure sensor as claimed in claim 7, wherein the diaphragm is formed from a material having a coefficient of thermal expansion of less than 10 ppm / °C. One end of the fixed section is upwardly bent to form a first rising section outside the seat, the first rising section is downwardly bent to form the first abutting portion away from the one end of the fixed section, the first abutting portion is upwardly electrically contacted with the electric contact portion, and the other end of the fixed section is upwardly bent to form a second rising section outside the seat, the second rising section is downwardly bent to form a descending section away from the one end of the fixed section, and the descending section is upwardly bent to form the second abutting portion away from the second rising section, the second abutting portion is downwardly electrically contacted with the upper portion of the terminal.

10. A pressure sensor as claimed in claim 1, wherein, The electric contact portion is arranged at an upper side surface of a first end of the substrate, the first abutting portion is downwardly abutted against the electric contact portion, and the pressure sensor further comprises a pressing element upwardly pressing the first end of the substrate, the pressing element is integrally connected with the seat.

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