Pressure sensor

Abstract

The invention belongs to the technical field of sensors, and discloses a pressure sensor. The pressure sensor comprises a first welding table, an isolation diaphragm, a second welding table, a cup base and a connecting pipe. A connecting hole is formed in the first welding table; the isolation diaphragm is arranged at the bottom of the first welding table, and the isolation diaphragm is arranged opposite to the opening of the connecting hole; the second welding table is welded to the end, away from the isolation diaphragm, of the first welding table, and the second welding table and the first welding table are made of different materials. The cup base and the second welding table are welded, a positive pressure oil cavity is defined in the cup base and the second welding table, and the cup base and the second welding table are made of the same material. One end of the connecting pipe is communicated with the positive pressure oil cavity, the other end of the connecting pipe penetrates through the second welding table and is arranged in the connecting hole, and the positive pressure oil cavity is communicated with the connecting hole through the connecting pipe. According to the invention, the problems of welding compatibility and reliability after the pressure sensing core body of the pressure sensor is made of different materials can be solved, and meanwhile, the cost is reduced.

Description

Technical Field

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

[0002] Pressure sensor is a widely used type of sensor. Pressure sensor is widely used in various industrial automatic control environments, involving water conservancy and hydropower, railway transportation, intelligent buildings, production automatic control, aerospace, military industry, petrochemical, oil wells, electricity, ships, machine tools, pipelines and many other industries. Pressure sensor (Pressure Transducer) is a device that can sense pressure signals and convert pressure signals into usable output electrical signals according to certain rules.

[0003] In the existing pressure sensor, the pressure sensor includes a pressure-sensitive core, wherein the pressure-sensitive core includes a cup seat and a diaphragm welding platform, and the cup seat is welded to the diaphragm welding platform.

[0004] At present, in order to ensure the welding quality and avoid cracking, the cup holder and the diaphragm welding base are usually required to be made of the same material. For example, if both the cup holder and the diaphragm welding base are made of stainless steel, but in some specific usage scenarios, the diaphragm welding base is often required to be made of special materials. Due to the welding compatibility problem between the special material and the stainless steel material, the molecules of the two materials are not tightly combined. After welding, capillary pores will appear between the cup holder and the diaphragm welding base, causing cracking, or cracking due to high pressure, which in turn causes oil leakage in the pressure sensor, resulting in the pressure sensor being unable to work normally. On the other hand, if both the cup holder and the diaphragm welding base are made of special materials, the cost of the special material is much higher than that of stainless steel, which will cause the problem of increased cost. Summary of the invention

[0005] The object of the present invention is to provide a pressure sensor for solving the welding compatibility and reliability problems of a pressure-sensitive core of the pressure sensor after using different materials, while taking into account cost reduction.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] Pressure sensor, including:

[0008] A first welding platform, wherein a connecting hole is provided on the first welding platform;

[0009] An isolation diaphragm is disposed at the bottom of the first welding platform, and the isolation diaphragm is disposed opposite to the opening of the connecting hole;

[0010] A second welding station is welded to an end of the first welding station away from the isolation diaphragm, and the second welding station and the first welding station are made of different materials;

[0011] A cup seat, welded to the second welding platform and enclosed inside the two to form a positive pressure oil chamber, the material of the cup seat and the second welding platform being the same;

[0012] A connecting pipe, one end of which is connected to the positive-pressure oil chamber, and the other end of which passes through the second welding platform and is placed in the connecting hole, and the positive-pressure oil chamber is connected to the connecting hole through the connecting pipe.

[0013] As an optional solution for the pressure sensor, a substrate is provided inside the cup holder, a connecting hole is provided on the substrate, and the pressure sensor also includes a pressure chip provided in the substrate, the pressure chip separates the connecting hole into a first hole and a second hole, the first hole is connected to the positive pressure oil chamber, and the second hole is connected to the external atmosphere.

[0014] As an optional solution for the pressure sensor, the substrate is made of ceramic material.

[0015] As an optional solution of the pressure sensor, an insulating plate is connected to a side of the second soldering station away from the first soldering station, and the insulating plate is arranged opposite to the pressure chip.

[0016] As an optional solution for the pressure sensor, a mounting hole is provided on the side wall of the cup holder, the mounting hole is communicated with the positive pressure oil chamber, and a breathing plug is provided in the mounting hole.

[0017] As an optional solution of the pressure sensor, the pressure sensor further includes a sleeve, the cup seat is arranged inside the sleeve, the sleeve is provided with an air hole, and the second hole is connected to the external atmosphere through the air hole.

[0018] As an optional solution of the pressure sensor, the pressure sensor further includes a shell, the shell is connected to the sleeve, a through hole is provided on the shell, the through hole is opposite to the isolation diaphragm, and the liquid or gas to be measured is introduced through the through hole.

[0019] As an optional solution of the pressure sensor, a ventilation plug is provided in the ventilation hole, and the external atmosphere is connected to the ventilation hole through the ventilation plug.

[0020] As an optional solution of the pressure sensor, a fixing ring is provided on the outer periphery of the isolation diaphragm, and the fixing ring is welded to the first welding platform so that the isolation diaphragm is fixed on the first welding platform.

[0021] As an optional solution for the pressure sensor, the cup holder is provided with a liquid injection hole, and the liquid injection hole is connected to the positive pressure oil chamber.

[0022] Beneficial effects:

[0023] In the present invention, the first welding station is used to fix the isolation diaphragm. The first welding station can be made of special materials to adapt to the special use occasions of the pressure sensor. The second welding station can be made of stainless steel to reduce the cost. At the same time, the second welding station is connected to the first welding station by welding. Further, the cup holder is welded with the second welding station and enclosed inside the two to form a positive pressure oil chamber. The cup holder can also be made of stainless steel. Since the second welding station and the cup holder are made of the same material, the welding connection of the same material has a better connection state and connection quality, which can effectively solve the cracking problem, thereby further avoiding the oil leakage problem between the cup holder and the second welding station. On the other hand, one end of the connecting pipe is connected to the positive pressure oil chamber, and the other end of the connecting pipe passes through the second welding station and is placed in the connecting hole, that is, the pressure oil can flow directly through the connecting pipe without flowing through the welding between the first welding station and the second welding station. Therefore, even if the first welding station and the second welding station are welded with different materials, or cracking occurs at the connection, there will be no oil leakage between the first welding station and the second welding station. The welding between the first welding station and the second welding station is only used to ensure a reliable connection between the two, and will not have no effect on defects such as cracking. Therefore, the present application effectively solves the welding compatibility and reliability issues of the pressure sensor after using different materials, and can also further reduce the manufacturing cost and enhance the price advantage of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional view of a pressure sensor provided by an embodiment of the present invention.

[0025] In the figure:

[0026] 1. First welding station; 2. Isolation diaphragm; 21. Fixed ring; 3. Second welding station; 31. Insulating plate; 4. Cup holder; 41. Positive pressure oil chamber; 42. Breathing plug; 43. Injection hole; 5. Connecting pipe; 6. Base plate; 61. Connecting hole; 62. Pressure chip; 611. First hole; 612. Second hole; 7. Sleeve; 71. Breathing plug; 8. Shell; 81. Through hole. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Please see attached Figure 1 The present embodiment relates to a pressure sensor, which can be specifically a gauge pressure sensor, and the pressure sensor includes a first welding platform 1, an isolation diaphragm 2, a second welding platform 3, a cup holder 4, and a connecting pipe 5. A connecting hole is provided on the first welding platform 1; the isolation diaphragm 2 is provided at the bottom of the first welding platform 1, and the isolation diaphragm 2 is arranged opposite to the opening of the connecting hole; the second welding platform 3 is welded to the end of the first welding platform 1 away from the isolation diaphragm 2, and the second welding platform 3 and the first welding platform 1 are made of different materials; the cup holder 4 is welded to the second welding platform 3 and encloses the positive pressure oil chamber 41 inside the two, and the material of the cup holder 4 is the same as that of the second welding platform 3; one end of the connecting pipe 5 is connected to the positive pressure oil chamber 41, and the other end of the connecting pipe 5 passes through the second welding platform 3 and is placed in the connecting hole, and the positive pressure oil chamber 41 is connected to the connecting hole through the connecting pipe 5.

[0032] In this embodiment, the first welding platform 1 and the second welding platform 3 are both circumferentially rotating bodies, wherein the first welding platform 1 is used to fix the isolation diaphragm 2. The first welding platform 1 can be made of special materials to adapt to the special use occasions of the pressure sensor. The second welding platform 3 can be made of 316 stainless steel to reduce costs. At the same time, the second welding platform 3 and the first welding platform 1 can be connected by brazing. Furthermore, the cup holder 4 is welded to the second welding platform 3 and enclosed inside the two to form a positive pressure oil chamber 41. The cup holder 4 can also be made of 316 stainless steel. Since the second welding platform 3 and the cup holder 4 are made of the same material, the welding connection of the same material has a better connection state and connection quality, which effectively solves the cracking problem, thereby further avoiding the oil leakage problem between the cup holder 4 and the second welding platform 3. On the other hand, one end of the connecting pipe 5 is connected to the positive pressure oil chamber 41, and the other end of the connecting pipe 5 passes through the second welding platform 3 and is placed in the connecting hole, and the pressure oil can flow directly through the connecting pipe 5 without flowing through the welding between the first welding platform 1 and the second welding platform 3. Therefore, even if the first welding platform 1 and the second welding platform 3 are welded with different materials and cracking occurs, the pressure oil will not leak between the first welding platform 1 and the second welding platform 3. The welding between the first welding platform 1 and the second welding platform 3 is only used to ensure a reliable connection between the two, and will not have no effect on defects such as cracking. The present application effectively solves the welding compatibility and reliability problems of the pressure sensor after using different materials, and can further reduce the manufacturing cost and enhance the price advantage of the product.

[0033] Preferably, the pressure oil is silicone oil.

[0034] Optionally, a substrate 6 is provided inside the cup holder 4, and a connecting hole 61 is opened on the substrate 6. The pressure sensor also includes a pressure chip 62 provided in the substrate 6, and the pressure chip 62 separates the connecting hole 61 into a first hole 611 and a second hole 612. The first hole 611 is connected to the positive pressure oil chamber 41, and the second hole 612 is connected to the external atmosphere.

[0035] In this embodiment, the substrate 6 is made of ceramic material, and the substrate 6 can occupy most of the space of the positive pressure oil chamber 41, thereby saving pressure oil. At the same time, since the thermal expansion coefficient of the substrate 6 is much lower than that of the pressure oil, while saving the filling of the pressure oil, it can also further reduce the sensitivity of the accuracy of the pressure sensor to the influence of temperature. A connecting hole 61 is opened at the center of the substrate 6, and a pressure chip 62 is placed horizontally in the middle of the connecting hole 61. The pressure chip 62 works according to the piezoresistance principle. When the pressure of the part to be measured changes, the resistance value will change, and then the pressure value is obtained through the change of the electrical signal (such as voltage or current).

[0036] In this embodiment, the connecting hole 61 is a strip hole, wherein the two sides of the pressure chip 62 separate the connecting hole 61 into a first hole 611 and a second hole 612, the first hole 611 is connected to the positive pressure oil chamber 41, that is, the positive pressure oil chamber 41 can produce pressure changes through the deformation of the isolation diaphragm 2, and the second hole 612 is connected to the external atmosphere, so that the other side of the pressure chip 62 uses the atmospheric pressure as the reference air pressure, thereby forming a relationship between the pressure to be measured and the reference air pressure.

[0037] Optionally, an insulating plate 31 is connected to a side of the second welding platform 3 away from the first welding platform 1 , and the insulating plate 31 is arranged opposite to the pressure chip 62 .

[0038] In this embodiment, an insulating plate 31 is also provided on the second soldering platform 3. The material of the insulating plate 31 is also ceramic. The insulating plate 31 is arranged between the pressure chip 62 and the second soldering platform 3. Since the second soldering platform 3 is made of metal, the insulating plate 31 can ensure that the pressure chip 62 and the second soldering platform 3 have a sufficient insulation gap, and the volume of the entire pressure sensor can be further reduced.

[0039] Optionally, a mounting hole is provided on the side wall of the cup holder 4, and a breathing plug 42 is provided in the mounting hole. The breathing plug 42 is a metal breathing plug. The breathing plug 42 can prevent sparks caused by weak electricity inside the pressure sensor from leaking outward, thereby playing an explosion-proof role and increasing the reliability of the sensor.

[0040] Optionally, the pressure sensor further includes a sleeve 7, the cup holder 4 is arranged inside the sleeve 7, the sleeve 7 is provided with an air hole, and the second hole 612 is connected to the external atmosphere through the air hole.

[0041] In this embodiment, the sleeve 7 is also a circumferential rotating body, and the cup holder 4 is located inside the sleeve 7, so that the breathing plug 42 can be stably limited in the mounting hole without falling off. In addition, the outer wall of the sleeve 7 is provided with a vent hole, and the second hole 612 is connected to the external atmosphere through the vent hole.

[0042] Furthermore, the pressure sensor further comprises a housing 8 , which is connected to the sleeve 7 , and a through hole 81 is provided on the housing 8 , which is opposite to the isolation diaphragm 2 , and the liquid or gas to be measured is introduced through the through hole 81 .

[0043] In this embodiment, the housing 8 is also a circumferentially rotating body, and the housing 8 and the sleeve 7 can be connected by screw connection. At the same time, the housing 8 has a through hole 81 relative to the isolation diaphragm 2, and the external gas or liquid to be measured can directly act on the isolation diaphragm 2 through the through hole 81 to deform the isolation diaphragm 2. The outer wall of the housing 8 is also provided with an external thread, which can be used to screw other structural parts to be measured.

[0044] Furthermore, a ventilation plug 71 is provided in the ventilation hole, and the external atmosphere is connected to the ventilation hole through the ventilation plug 71.

[0045] The air plug 71 will not affect the connection between the air hole and the external atmosphere, so there is atmospheric pressure on both sides of the air hole. In addition to the ventilation function, the air plug 71 can further prevent liquid from passing through, thereby achieving the purpose of waterproofing. The air plug 71 can adopt the existing conventional structure. The specific working principle of the air plug 71 will not be elaborated in this embodiment.

[0046] Optionally, a fixing ring 21 is provided on the outer periphery of the isolation diaphragm 2 , and the fixing ring 21 is welded to the first welding platform 1 , so that the isolation diaphragm 2 is fixed on the first welding platform 1 .

[0047] The fixing ring 21 is sleeved on the circumferential outer edge of the isolation diaphragm 2, and the isolation diaphragm 2 is reliably fixed on the first welding platform 1 by welding the fixing ring 21 to the first welding platform 1. Of course, in other embodiments, other fixing methods can also be used to fix the isolation diaphragm 2 on the first welding platform 1. For example, threaded fasteners or rivets are used to fasten the isolation diaphragm 2 to the first welding platform 1.

[0048] Optionally, the cup holder 4 is provided with a liquid injection hole 43, which is connected to the positive pressure oil chamber 41. No liquid injection tube may be provided in the liquid injection hole 43, and pressure oil may be added to the positive pressure oil chamber 41 through the liquid injection hole 43. After the liquid injection is completed, the liquid injection hole 43 needs to be sealed.

[0049] The working principle of this pressure sensor is as follows:

[0050] First, the liquid or gas to be measured pressure is passed into the through hole 81. The liquid or gas acts on the isolation diaphragm 2, causing it to deform and squeeze the pressure oil in the positive pressure oil chamber 41. Since the volume of the pressure oil remains unchanged, it will further act on the pressure chip 62. The force signal is converted into an electrical signal through the pressure chip 62, thereby realizing the pressure detection of the liquid or gas.

[0051] 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 pressure sensor, characterized in that include: A first welding platform (1), wherein the first welding platform (1) is provided with a connecting hole; An isolation diaphragm (2) is arranged at the bottom of the first welding platform (1), and the isolation diaphragm (2) is arranged opposite to the opening of the connecting hole; A second welding platform (3) is welded to an end of the first welding platform (1) away from the isolation diaphragm (2), and the second welding platform (3) and the first welding platform (1) are made of different materials; A cup seat (4) is welded to the second welding platform (3) and encloses a positive pressure oil chamber (41) therein; the cup seat (4) is made of the same material as the second welding platform (3); A connecting pipe (5), one end of which is connected to the positive-pressure oil chamber (41), the other end of which passes through the second welding platform (3) and is placed in the connecting hole, and the positive-pressure oil chamber (41) is connected to the connecting hole through the connecting pipe (5).

2. The pressure sensor according to claim 1, characterized in that: A base plate (6) is provided inside the cup holder (4), and a connecting hole (61) is provided on the base plate (6). The pressure sensor further comprises a pressure chip (62) provided inside the base plate (6), and the pressure chip (62) separates the connecting hole (61) into a first hole (611) and a second hole (612), wherein the first hole (611) is connected to the positive pressure oil chamber (41), and the second hole (612) is connected to the external atmosphere.

3. The pressure sensor according to claim 2, characterized in that: The substrate (6) is made of ceramic material.

4. The pressure sensor according to claim 2, characterized in that: An insulating plate (31) is connected to a side of the second welding platform (3) away from the first welding platform (1), and the insulating plate (31) is arranged opposite to the pressure chip (62).

5. The pressure sensor according to claim 2, characterized in that: A mounting hole is provided on the side wall of the cup seat (4), the mounting hole is communicated with the positive pressure oil chamber (41), and a breathing plug (42) is provided in the mounting hole.

6. The pressure sensor according to claim 2, characterized in that: The pressure sensor further comprises a sleeve (7), the cup holder (4) is arranged inside the sleeve (7), the sleeve (7) is provided with an air vent, and the second hole (612) is connected to the external atmosphere through the air vent.

7. The pressure sensor according to claim 6, characterized in that: The pressure sensor further comprises a housing (8), wherein the housing (8) is connected to the sleeve (7), and a through hole (81) is provided on the housing (8), wherein the through hole (81) is opposite to the isolation diaphragm (2), and liquid or gas of a pressure to be measured is introduced through the through hole (81).

8. The pressure sensor according to claim 6, characterized in that: A ventilation plug (71) is provided in the ventilation hole, and the external atmosphere is connected to the ventilation hole through the ventilation plug (71).

9. The pressure sensor according to any one of claims 1 to 8, characterized in that: A fixing ring (21) is provided on the outer periphery of the isolation diaphragm (2), and the fixing ring (21) is welded to the first welding platform (1) so that the isolation diaphragm (2) is fixed on the first welding platform (1).

10. The pressure sensor according to any one of claims 1 to 8, characterized in that: The cup seat (4) is provided with a liquid injection hole (43), and the liquid injection hole (43) is communicated with the positive pressure oil chamber (41).

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