Differential pressure sensor

Abstract

The invention belongs to the technical field of pressure detection equipment, and discloses a differential pressure sensor which comprises a base body assembly, an overload protection diaphragm assembly, a mounting seat and a pipeline assembly. The base body assembly comprises a positive pressure base body, a middle base body and a negative pressure base body which are arranged in sequence; the overload protection diaphragm assembly comprises a first overload protection diaphragm located between the positive pressure base body and the middle base body and a second overload protection diaphragm located between the middle base body and the negative pressure base body. The mounting seat with the pressure sensing chip is arranged on the base body assembly; pressure guide liquid is arranged in the pipeline assembly, and the pipeline assembly enables the overload protection diaphragm assembly to play a role in protecting the pressure sensing chip. The differential pressure sensor is provided with the first overload protection diaphragm and the second overload protection diaphragm, and when the base body is subjected to instantaneous pressure, the first overload protection diaphragm and the second overload protection diaphragm can deform together to reduce the stress generated at the pressure sensing chip. And the two can generate enough deformation quantity in a short time so as to realize a better protection effect on the pressure sensing chip.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure detection equipment, and in particular to a differential pressure sensor. Background Art

[0002] A differential pressure sensor is a sensor used to measure the pressure difference between two locations or environments. It is widely used in fluid pressure and flow measurement devices. The differential pressure sensor converts two pressure signals at different positions of the fluid into changes in electrical signals, and then analyzes the electrical signals to obtain the differential pressure value of the applied pressure. The differential pressure sensor usually includes a substrate and a pressure measuring cavity in a mounting seat. When pressure is applied to both sides of the substrate, the silicone oil and other media in the substrate can generate corresponding pressure in the pressure measuring cavity. The pressure measuring cavity includes a detection chip that can generate an electrical signal according to the pressure in the pressure measuring cavity.

[0003] In the prior art, the differential pressure sensor is usually provided with an overload protection diaphragm, which is located in the substrate. When the substrate is subjected to pressure, silicone oil and other media will enter the pressure measuring cavity after being buffered by the overload protection diaphragm to prevent the detection chip from being damaged by excessive pressure. However, sudden pressurization or pressure relief during on-site use will still cause excessive pressure to break through the detection chip. Summary of the invention

[0004] The object of the present invention is to provide a differential pressure sensor, which can reduce the stress generated at the pressure sensing chip, so as to better protect the pressure sensing chip in the differential pressure sensor.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A differential pressure sensor, comprising:

[0007] A base assembly, the base assembly comprising a positive pressure base, an intermediate base and a negative pressure base arranged in sequence, the positive pressure base having a positive pressure surface on a side away from the negative pressure base, and the negative pressure base having a negative pressure surface on a side away from the positive pressure base;

[0008] An overload protection diaphragm assembly, the overload protection diaphragm assembly comprising a first overload protection diaphragm and a second overload protection diaphragm, the first overload protection diaphragm is located between the positive pressure substrate and the intermediate substrate, and the second overload protection diaphragm is located between the intermediate substrate and the negative pressure substrate;

[0009] A mounting seat, the mounting seat is arranged on the base assembly, a pressure sensing chip is arranged in the mounting seat, and the pressure sensing chip includes a positive pressure detection surface and a negative pressure detection surface which are isolated from each other;

[0010] A pipeline assembly, wherein a pressure-conducting liquid is arranged in the pipeline assembly, and the pipeline assembly includes a positive-pressure pipeline assembly and a negative-pressure pipeline assembly, wherein the positive-pressure pipeline assembly enables the positive-pressure surface, the first overload protection diaphragm, the second overload protection diaphragm and the positive-pressure detection surface to be interconnected, and the negative-pressure pipeline assembly enables the negative-pressure surface, the first overload protection diaphragm, the second overload protection diaphragm and the negative-pressure detection surface to be interconnected.

[0011] Preferably, the positive pressure pipeline assembly includes a positive pressure pipe, which can connect the positive pressure surface with the first overload protection diaphragm; the negative pressure pipeline assembly includes a negative pressure pipe, which can connect the negative pressure surface with the second overload protection diaphragm.

[0012] Preferably, the positive pressure pipe assembly also includes a first positive pressure pipe, a second positive pressure pipe and a third positive pressure pipe, the first positive pressure pipe is arranged on the positive pressure base and can connect the first overload protection diaphragm and the third positive pressure pipe, the second positive pressure pipe is arranged on the intermediate base and can connect the second overload protection diaphragm and the third positive pressure pipe, and the third positive pressure pipe is located in the mounting seat and is connected to the positive pressure detection surface.

[0013] Preferably, the negative pressure pipe assembly also includes a first negative pressure pipe, a second negative pressure pipe and a third negative pressure pipe, the first negative pressure pipe is arranged in the intermediate base and can connect the first overload protection diaphragm and the third negative pressure pipe, the second negative pressure pipe is arranged in the negative pressure base and can connect the second overload protection diaphragm and the third negative pressure pipe, and the third negative pressure pipe is located in the mounting seat and is connected to the negative pressure detection surface.

[0014] Preferably, the mounting seat is fixed to the base assembly via a positioning pin, a liquid through hole is provided in the positioning pin, and the first positive pressure pipeline and the second positive pressure pipeline are connected to the third positive pressure pipeline via the liquid through hole.

[0015] Preferably, a first liquid passage groove is provided between the mounting seat and the base assembly, and the first positive pressure pipeline is connected with the liquid passage hole through the first liquid passage groove.

[0016] Preferably, a second liquid-passing groove is provided between the mounting seat and the base assembly, and the first negative-pressure pipeline is connected to the third negative-pressure pipeline through the second liquid-passing groove.

[0017] Preferably, a positive pressure filling tube and a negative pressure filling tube are respectively provided on the mounting seat, the positive pressure filling tube can connect the positive pressure detection surface with the outside world, and the negative pressure filling tube can connect the negative pressure detection surface with the outside world.

[0018] Preferably, a positive pressure isolation diaphragm is arranged outside the positive pressure surface, and a pressure-conducting liquid is arranged in the gap between the positive pressure surface and the positive pressure isolation diaphragm; a negative pressure isolation diaphragm is arranged on the negative pressure surface, and a pressure-conducting liquid is arranged in the gap between the negative pressure surface and the negative pressure isolation diaphragm.

[0019] Preferably, the surfaces of the positive pressure surface and the negative pressure surface are corrugated surfaces.

[0020] Beneficial effects:

[0021] The present invention provides a differential pressure sensor, which includes a base component, an overload protection diaphragm component, a mounting seat and a pipeline component. The base component includes a positive pressure base, an intermediate base and a negative pressure base arranged in sequence; the overload protection diaphragm component includes a first overload protection diaphragm and a second overload protection diaphragm, the first overload protection diaphragm is located between the positive pressure base and the intermediate base, and the second overload protection diaphragm is located between the intermediate base and the negative pressure base; the mounting seat is arranged at one end of the base component, and a pressure sensing chip is arranged in the mounting seat; a pressure-conducting liquid is arranged in the pipeline component, and the pipeline component can connect the pressure sensing chip with the overload protection diaphragm component, so that the overload protection diaphragm component can protect the pressure sensing chip. The above-mentioned differential pressure sensor is provided with a first overload protection diaphragm and a second overload protection diaphragm. When instantaneous pressure is generated on the positive pressure surface and the negative pressure surface, the pressure-conducting fluid in the pipeline assembly can cause the first overload protection diaphragm and the second overload protection diaphragm to deform together to reduce the stress generated at the pressure-sensitive chip. The two can jointly generate sufficient deformation in a short period of time to achieve better protection for the pressure-sensitive chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a front cross-sectional view of the differential pressure sensor provided by the present invention;

[0023] Figure 2 is a side sectional view of the differential pressure sensor provided by the present invention;

[0024] Figure 3 It is a schematic diagram of the position of the pipeline components of the differential pressure sensor provided by the present invention.

[0025] In the figure:

[0026] 1. Base assembly; 11. Positive pressure base; 111. Positive pressure surface; 12. Intermediate base; 13. Negative pressure base; 131. Negative pressure surface;

[0027] 2. Overload protection diaphragm assembly; 21. First overload protection diaphragm; 22. Second overload protection diaphragm;

[0028] 3. Mounting seat; 31. Silicon seat; 32. Transfer table; 33. Welding sleeve;

[0029] 4. Pressure sensing chip;

[0030] 5. Positive pressure pipeline assembly; 51. Positive pressure lead pipe; 52. First positive pressure pipeline; 53. Second positive pressure pipeline; 54. Third positive pressure pipeline;

[0031] 6. Negative pressure pipeline assembly; 61. Negative pressure guide pipe; 62. First negative pressure pipeline; 63. Second negative pressure pipeline; 64. Third negative pressure pipeline;

[0032] 7. Positioning pin;

[0033] 8. Positive pressure filling pipe;

[0034] 9. Negative pressure filling tube. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0036] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0038] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0039] like Figure 1-Figure 3 As shown, this embodiment provides a differential pressure sensor, which includes a base assembly 1, an overload protection diaphragm assembly 2, a mounting seat 3 and a pipeline assembly. The base assembly 1 includes a positive pressure base 11, an intermediate base 12 and a negative pressure base 13 arranged in sequence, and a positive pressure surface 111 is provided on the side of the positive pressure base 11 away from the negative pressure base 13, and a negative pressure surface 131 is provided on the side of the negative pressure base 13 away from the positive pressure base 11. The positive pressure surface 111 is used to receive the positive pressure generated by the outside world, and the negative pressure surface 131 is used to receive the negative pressure generated by the outside world. The overload protection diaphragm assembly 2 includes a first overload protection diaphragm 21 and a second overload protection diaphragm 22, the first overload protection diaphragm 21 is located between the positive pressure base 11 and the intermediate base 12, and the second overload protection diaphragm 22 is located between the intermediate base 12 and the negative pressure base 13. The overload protection diaphragm assembly 2 is welded and fixed to the base assembly 1 so that the whole has sufficient structural strength. The mounting seat 3 is arranged on the base component 1, and a pressure sensing chip 4 is arranged in the mounting seat 3. The pressure sensing chip 4 includes a positive pressure detection surface and a negative pressure detection surface that are isolated from each other. When the positive pressure detection surface and the negative pressure detection surface of the pressure sensing chip 4 change, the resistance value thereof will change, thereby generating a corresponding electrical signal, and finally obtaining the size of the positive pressure and the negative pressure. A pressure-conducting liquid is arranged in the pipeline component, and the pipeline component includes a positive pressure pipeline component 5 and a negative pressure pipeline component 6. The positive pressure pipeline component 5 can make the positive pressure surface 111, the first overload protection diaphragm 21, the second overload protection diaphragm 22 and the positive pressure detection surface interconnected, and the negative pressure pipeline component 6 can make the negative pressure surface 131, the first overload protection diaphragm 21, the second overload protection diaphragm 22 and the negative pressure detection surface interconnected.

[0040] Taking the case where the differential pressure sensor is subjected to positive pressure as an example, the positive pressure surface 111 is subjected to positive pressure, and the positive pressure is transmitted to the first overload protection diaphragm 21, the second overload protection diaphragm 22 and the positive pressure detection surface through the pressure-conducting liquid. The pressure-conducting liquid is filled in the pipeline assembly, and the positive pressure can be quickly transmitted when the positive pressure is generated. Therefore, when the positive pressure is transmitted to the positive pressure detection surface, it will also be transmitted to the first overload protection diaphragm 21 and the second overload protection diaphragm 22. The first overload protection diaphragm 21 and the second overload protection diaphragm 22 are deformed under pressure, which can absorb and reduce the instantaneous pressure inside the pressure-conducting liquid. The instantaneous pressure generated by the pressure-conducting liquid on the positive pressure detection surface is also reduced, avoiding the breakdown of the pressure-sensing chip 4 due to excessive instantaneous pressure. The working principle of the differential pressure sensor when subjected to negative pressure is similar to the above principle, and this embodiment will not be repeated.

[0041] The overload protection diaphragm assembly 2 is a prior art. Taking an overload protection diaphragm in the prior art as an example, the overload protection diaphragm is made of metal, and the substrates on both sides of the overload protection diaphragm have a certain gap with the overload protection diaphragm. When pressure is generated at the overload protection diaphragm, a convex deformation toward the low-pressure side will be generated to reduce the instantaneous pressure of the pressure-conducting fluid. When the deformation is the largest, it will be close to the corresponding substrate to achieve overload protection. Those skilled in the art can select a specific type of overload protection diaphragm according to actual needs, and this embodiment does not limit this.

[0042] In the prior art, a single overload protection diaphragm is used for overload protection. When the differential pressure sensor is suddenly pressurized or released, the single overload protection diaphragm is prone to not being able to immediately generate enough deformation to reduce the pressure of the pressure-conducting fluid, which can easily cause the pressure-conducting fluid to break through the pressure-sensing chip 4. Compared with the differential pressure sensor in the prior art, the present embodiment is provided with a first overload protection diaphragm 21 and a second overload protection diaphragm 22. When the positive pressure surface 111 and the negative pressure surface 131 generate instantaneous pressure, the first overload protection diaphragm 21 and the second overload protection diaphragm 22 can be deformed together to reduce the stress generated at the pressure-sensing chip 4. The two can jointly generate enough deformation in a short time to achieve a better protection effect on the pressure-sensing chip 4.

[0043] Specifically, in this embodiment, the positive pressure pipeline assembly 5 includes a positive pressure lead pipe 51, which can connect the positive pressure surface 111 with the first overload protection diaphragm 21; the negative pressure pipeline assembly 6 includes a negative pressure lead pipe 61, which can connect the negative pressure surface 131 with the second overload protection diaphragm 22. When the positive pressure surface 111 and the negative pressure surface 131 are subjected to force, the positive pressure lead pipe 51 and the negative pressure lead pipe 61 can directly transmit the force to the overload protection diaphragm assembly 2 through the pressure-conducting fluid, and the buffering of the overload protection diaphragm assembly 2 can prevent the pressure sensing chip 4 from being subjected to excessive force, thereby preventing it from being punctured and damaged. Furthermore, two positive pressure pipes 51 and two negative pressure pipes 61 are provided. The two positive pressure pipes 51 are located in the positive pressure base 11 and are respectively spaced apart at the upper and lower parts of the first overload protection diaphragm 21. The two negative pressure pipes 61 are located in the negative pressure base 13 and are respectively spaced apart at the upper and lower parts of the second overload protection diaphragm 22. The two positive pressure pipes 51 and the two negative pressure pipes 61 facilitate timely and sufficient pressure transmission by the pressure-conducting liquid.

[0044] Furthermore, in this embodiment, the positive pressure pipeline assembly 5 also includes a first positive pressure pipeline 52, a second positive pressure pipeline 53 and a third positive pressure pipeline 54. The first positive pressure pipeline 52 is arranged on the positive pressure base 11 and can connect the first overload protection diaphragm 21 and the third positive pressure pipeline 54. The second positive pressure pipeline 53 is arranged on the intermediate base 12 and can connect the second overload protection diaphragm 22 and the third positive pressure pipeline 54. The third positive pressure pipeline 54 is located in the mounting seat 3 and is connected to the positive pressure detection surface. Specifically, one end of the first positive pressure pipeline 52 is connected to the side of the first overload protection diaphragm 21 close to the positive pressure base 11, and the other end is used to communicate with the third positive pressure pipeline 54; one end of the second positive pressure pipeline 53 is connected to the side of the second overload protection diaphragm 22 close to the intermediate base 12, and the other end is used to communicate with the third positive pressure pipeline 54; and the third positive pressure pipeline 54 itself is connected to the positive pressure detection surface. Therefore, the first overload protection diaphragm 21, the second overload protection diaphragm 22 and the positive pressure detection surface are connected. When the positive pressure surface 111 is subjected to pressure, the pressure first acts on the first overload protection diaphragm 21 through the positive pressure pipe 51, and then transmits the pressure to the second positive pressure pipe 53 and the third positive pressure pipe 54 through the first positive pressure pipe 52 and acts on the second overload protection diaphragm 22 and the positive pressure detection surface respectively. The first overload protection diaphragm 21 and the second overload protection diaphragm 22 deform together to reduce the instantaneous pressure on the positive pressure detection surface. It can be understood that the pressure-conducting fluid is filled in the above-mentioned pipes and can conduct pressure without large-scale flow. Therefore, the above description is about the direction of force conduction and the mechanism of action of the overload protection diaphragm, but does not limit the specific flow of the pressure-conducting fluid, and does not mean that the pressure-conducting fluid in the positive pressure pipe 51 passes through the first overload protection diaphragm 21 and the second overload protection diaphragm 22 and then enters the positive pressure detection surface.

[0045] Furthermore, in this embodiment, the negative pressure pipe assembly 6 also includes a first negative pressure pipe 62, a second negative pressure pipe 63 and a third negative pressure pipe 64. The first negative pressure pipe 62 is arranged on the negative pressure base 13 and can connect the first overload protection diaphragm 21 and the third negative pressure pipe 64. The second negative pressure pipe 63 is arranged on the intermediate base 12 and can connect the second overload protection diaphragm 22 and the third negative pressure pipe 64. The third negative pressure pipe 64 is located in the mounting seat 3 and is connected to the negative pressure detection surface. Specifically, one end of the first negative pressure pipe 62 is connected to the side of the second overload protection diaphragm 22 close to the negative pressure base 13, and the other end is used to communicate with the third negative pressure pipe 64; one end of the second negative pressure pipe 63 is connected to the side of the first overload protection diaphragm 21 close to the intermediate base 12, and the other end is used to communicate with the third negative pressure pipe 64; and the third negative pressure pipe 64 itself is connected to the negative pressure detection surface. Therefore, the first overload protection diaphragm 21, the second overload protection diaphragm 22 and the negative pressure detection surface are connected. When the negative pressure surface 131 is subjected to negative pressure, the negative pressure first acts on the second overload protection diaphragm 22 through the negative pressure guiding pipe 61, and then transmits the negative pressure to the first negative pressure pipe 62 and the third negative pressure pipe 64 through the second negative pressure pipe 63 and acts on the first overload protection diaphragm 21 and the negative pressure detection surface respectively. The first overload protection diaphragm 21 and the second overload protection diaphragm 22 deform together to reduce the instantaneous force on the negative pressure detection surface. It can be understood that the pressure-conducting liquid is filled in the above-mentioned pipes and can conduct pressure without large-scale flow. Therefore, the above description is about the force conduction direction and the action mechanism of the overload protection diaphragm, but does not limit the specific flow of the pressure-conducting liquid, and does not mean that the pressure-conducting liquid in the negative pressure guiding pipe 61 enters the negative pressure detection surface after passing through the first overload protection diaphragm 21 and the second protection diaphragm.

[0046] Furthermore, in the present embodiment, the mounting seat 3 is fixed to the base assembly 1 by means of a positioning pin 7, a liquid through hole is provided in the positioning pin 7, and the first positive pressure pipeline 52 and the second positive pressure pipeline 53 are connected to the third positive pressure pipeline 54 through the liquid through hole. The surface of the positioning pin 7 is provided with a thread, one end of the positioning pin 7 is threadedly connected to the intermediate base 12, and the other end is threadedly connected to the mounting seat 3, that is, the mounting seat 3 can be fixed to the intermediate base 12 by using the positioning pin 7 to achieve relative fixation of the mounting seat 3 and the base assembly 1. At the same time, the positioning pin 7 is provided with a liquid through hole, and the first positive pressure pipeline 52 and the second positive pressure pipeline 53 are connected to the third positive pressure pipeline 54 in the mounting seat 3 through the liquid through hole. The positive pressure detection surface is directly above the third positive pressure pipeline 54. It can be understood that the positive pressure detection surface is the bottom surface of the pressure sensing chip 4. When the positive pressure surface 111 is not subjected to pressure, the pressure-conducting liquid contacts the positive pressure detection surface but does not apply pressure to the positive pressure detection surface or applies very little pressure; when the positive pressure surface 111 is subjected to pressure, the positive pressure is transmitted through the pressure-conducting liquid, causing the positive pressure detection surface to be subjected to upward pressure to change the resistance of the pressure-sensing chip 4 and generate an electrical signal.

[0047] Furthermore, the positioning pin 7 in this embodiment is a damping positioning pin 7, which has a damping effect, slows down the relative movement between the mounting seat 3 and the base assembly 1, and improves the stability and durability of the system.

[0048] Furthermore, the mounting base 3 includes an adapter 32, a silicon base 31 and a welding sleeve 33. The adapter 32 is directly connected to the intermediate base 12 through the damping positioning pin 7, the silicon base 31 is arranged on the upper surface of the adapter 32, the pressure sensing chip 4 is arranged inside the silicon base 31, and the welding sleeve 33 is sleeved on the outer peripheral surface of the adapter 32 and the silicon base 31 to achieve relative fixation of the silicon base 31 and the adapter 32, and at the same time, the bottom of the welding sleeve 33 abuts against the base component 1, and welding is performed on the contact outer edge of the welding sleeve 33 and the base component 1 to improve the sealing between the mounting base 3 and the base component 1.

[0049] Furthermore, in the present embodiment, a first liquid-through groove is provided between the mounting seat 3 and the base assembly 1, and the first positive pressure pipeline 52 is connected to the liquid-through hole through the first liquid-through groove. Specifically, a first liquid-through groove is provided between the adapter 32 and the base assembly 1, one end of the first liquid-through groove is connected to the first positive pressure pipeline 52, and the other end is connected to the liquid-through hole. Specifically, the positioning pin 7 includes a liquid-through hole that passes through from top to bottom, the second positive pressure pipeline 53 enters from bottom to top and is connected to the liquid-through hole, and the positioning pin 7 includes a transverse liquid-through hole, the transverse liquid-through hole is connected to the liquid-through hole that passes through from top to bottom, and the first positive pressure pipeline 52 is connected to the transverse liquid-through hole through the first liquid-through groove. The first liquid-through groove can be a depression provided on the adapter 32; it can also be a depression provided on the intermediate base 12; it can also be a partial depression provided on each of the two to combine into a complete first liquid-through groove, which is not limited in the present embodiment.

[0050] Furthermore, in the present embodiment, a second liquid-through groove is provided between the mounting seat 3 and the base assembly 1, and the first negative pressure pipeline 62 is connected to the third negative pressure pipeline 64 through the second liquid-through groove. Specifically, one end of the second liquid-through groove is connected to the first negative pressure pipeline 62, and the other end is connected to the bottom of the third negative pressure pipeline 64. Specifically, the third negative pressure pipeline 64 can be divided into three sections, namely, a first section directly connected to the pressure sensing chip 4, a second section directly connected to the first section and horizontally arranged, and a third section connected to the base assembly 1 at one end and connected to the second section and passing through the mounting seat 3 at the other end. The second liquid-through groove is connected to the bottom of the third section. In order to avoid the vertically arranged first positive pressure pipeline 52, the first negative pressure pipeline 62 is at a certain angle to the vertical direction and extends to the second liquid-through groove. At the same time, the corresponding positions of the mounting seat 3 and the second negative pressure pipeline 63 are also provided with a liquid-through structure for connecting the third negative pressure pipeline 64, which will not be repeated here. It can be understood that the third negative pressure pipe 64 is connected to the negative pressure detection surface, and the negative pressure detection surface is the top surface of the chip. When the negative pressure surface 131 is not subjected to force, since the third negative pressure pipe 64 is filled with pressure-conducting liquid, there is a certain liquid column in the first section that has a certain downward initial pressure on the pressure-sensitive chip 4; when the negative pressure surface 131 is under pressure, the negative pressure is transmitted through the pressure-conducting liquid, so that the downward initial pressure on the pressure-sensitive chip 4 is reduced or an upward negative pressure is generated to cause the pressure-sensitive chip 4 to generate an electrical signal.

[0051] Specifically, in this embodiment, a positive pressure filling pipe 8 and a negative pressure filling pipe 9 are respectively provided on the mounting seat 3, and the positive pressure filling pipe 8 can connect the positive pressure detection surface with the outside world, and the negative pressure filling pipe 9 can connect the negative pressure detection surface with the outside world. The positive pressure pipeline assembly 5 and the negative pressure pipeline assembly 6 of the differential pressure sensor are respectively filled with pressure-conducting liquid through the positive pressure filling pipe 8 and the negative pressure filling pipe 9, and the pressure-conducting liquid is evenly distributed in the pipeline assembly. The pressure-conducting liquid can be silicone oil, fluorine oil, vegetable oil or other media, which is not limited in this embodiment.

[0052] Specifically, in this embodiment, a positive pressure isolation diaphragm is provided outside the positive pressure surface 111, and a pressure-conducting liquid is provided in the gap between the positive pressure surface 111 and the positive pressure isolation diaphragm; a negative pressure isolation diaphragm is provided on the negative pressure surface 131, and a pressure-conducting liquid is provided in the gap between the negative pressure surface 131 and the negative pressure isolation diaphragm. Taking the positive pressure surface 111 as an example, when the positive pressure surface 111 is subjected to positive pressure, the positive pressure isolation diaphragm approaches the positive pressure surface 111, and the two together squeeze the pressure-conducting liquid in the gap, and the pressure in the pressure-conducting liquid is then transmitted through the positive pressure conducting pipe, that is, there is a liquid cavity of the pressure-conducting liquid between the positive pressure surface 111 and the positive pressure isolation diaphragm, and the positive pressure conducting pipe is connected to the liquid cavity to transmit positive pressure. The working principle of the negative pressure surface 131 is similar to the above principle, and this embodiment will not be repeated.

[0053] Furthermore, in this embodiment, the surface of the positive pressure surface 111 and the negative pressure surface 131 are corrugated surfaces. The positive pressure substrate 11 and the negative pressure substrate 13 are both rigid structures, and the positive pressure isolation diaphragm and the negative pressure isolation diaphragm have a certain elasticity. When subjected to external forces, the corrugated surface is more conducive to the rebound of the positive pressure isolation diaphragm and the negative pressure isolation diaphragm.

[0054] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A differential pressure sensor, characterized in that: include: A base assembly (1), the base assembly (1) comprising a positive pressure base (11), an intermediate base (12) and a negative pressure base (13) arranged in sequence, the positive pressure base (11) being provided with a positive pressure surface (111) on a side away from the negative pressure base (13), and the negative pressure base (13) being provided with a negative pressure surface (131) on a side away from the positive pressure base (11); An overload protection diaphragm assembly (2), the overload protection diaphragm assembly (2) comprising a first overload protection diaphragm (21) and a second overload protection diaphragm (22), the first overload protection diaphragm (21) being located between the positive pressure substrate (11) and the intermediate substrate (12), and the second overload protection diaphragm (22) being located between the intermediate substrate (12) and the negative pressure substrate (13); A mounting seat (3), the mounting seat (3) being arranged on the base assembly (1), a pressure sensing chip (4) being arranged inside the mounting seat (3), the pressure sensing chip (4) comprising a positive pressure detection surface and a negative pressure detection surface which are isolated from each other; A pipeline assembly, wherein a pressure-conducting liquid is arranged in the pipeline assembly, and the pipeline assembly comprises a positive-pressure pipeline assembly (5) and a negative-pressure pipeline assembly (6); the positive-pressure pipeline assembly (5) enables the positive-pressure surface (111), the first overload protection diaphragm (21), the second overload protection diaphragm (22) and the positive-pressure detection surface to be interconnected; and the negative-pressure pipeline assembly (6) enables the negative-pressure surface (131), the first overload protection diaphragm (21), the second overload protection diaphragm (22) and the negative-pressure detection surface to be interconnected.

2. The differential pressure sensor according to claim 1, characterized in that: The positive pressure pipeline assembly (5) comprises a positive pressure lead pipe (51), and the positive pressure lead pipe (51) can connect the positive pressure surface (111) with the first overload protection diaphragm (21); the negative pressure pipeline assembly (6) comprises a negative pressure lead pipe (61), and the negative pressure lead pipe (61) can connect the negative pressure surface (131) with the second overload protection diaphragm (22).

3. The differential pressure sensor according to claim 2, characterized in that: The positive pressure pipe assembly (5) further comprises a first positive pressure pipe (52), a second positive pressure pipe (53) and a third positive pressure pipe (54); the first positive pressure pipe (52) is arranged on the positive pressure base (11) and is capable of connecting the first overload protection diaphragm (21) and the third positive pressure pipe (54); the second positive pressure pipe (53) is arranged on the intermediate base (12) and is capable of connecting the second overload protection diaphragm (22) and the third positive pressure pipe (54); the third positive pressure pipe (54) is located in the mounting seat (3) and is connected to the positive pressure detection surface.

4. The differential pressure sensor according to claim 2, characterized in that: The negative pressure pipe assembly (6) further comprises a first negative pressure pipe (62), a second negative pressure pipe (63) and a third negative pressure pipe (64); the first negative pressure pipe (62) is arranged on the intermediate base (12) and is capable of connecting the first overload protection diaphragm (21) and the third negative pressure pipe (64); the second negative pressure pipe (63) is arranged on the negative pressure base (13) and is capable of connecting the second overload protection diaphragm (22) and the third negative pressure pipe (64); the third negative pressure pipe (64) is located in the mounting seat (3) and is connected to the negative pressure detection surface.

5. The differential pressure sensor according to claim 3, characterized in that: The mounting seat (3) is fixed to the base assembly (1) via a positioning pin (7); a liquid through hole is provided in the positioning pin (7); the first positive pressure pipeline (52) and the second positive pressure pipeline (53) are connected to the third positive pressure pipeline (54) via the liquid through hole.

6. The differential pressure sensor according to claim 5, characterized in that: A first liquid passage groove is provided between the mounting seat (3) and the base assembly (1), and the first positive pressure pipeline (52) is connected to the liquid passage hole through the first liquid passage groove.

7. The differential pressure sensor according to claim 4, characterized in that: A second liquid-passing groove is provided between the mounting seat (3) and the base assembly (1), and the first negative-pressure pipeline (62) is connected to the third negative-pressure pipeline (64) through the second liquid-passing groove.

8. The differential pressure sensor according to any one of claims 1 to 6, characterized in that: The mounting seat (3) is provided with a positive pressure filling pipe (8) and a negative pressure filling pipe (9), respectively. The positive pressure filling pipe (8) can connect the positive pressure detection surface with the outside world, and the negative pressure filling pipe (9) can connect the negative pressure detection surface with the outside world.

9. The differential pressure sensor according to any one of claims 1 to 6, characterized in that: A positive pressure isolation diaphragm is arranged outside the positive pressure surface (111), and a pressure-conducting liquid is arranged in the gap between the positive pressure surface (111) and the positive pressure isolation diaphragm; a negative pressure isolation diaphragm is arranged on the negative pressure surface (131), and a pressure-conducting liquid is arranged in the gap between the negative pressure surface (131) and the negative pressure isolation diaphragm.

10. The differential pressure sensor according to claim 9, characterized in that: The surfaces of the positive pressure surface (111) and the negative pressure surface (131) are corrugated surfaces.

Images