阅读说明：本技术 一种减小感压薄膜焊接应力的电容压力传感器 (Capacitance pressure sensor for reducing welding stress of pressure sensing film ) 是由 裴晓强 成永军 孙雯君 丁栋 习振华 董猛 吴成耀 宋伊 高洁 于 2020-12-11 设计创作，主要内容包括：本发明公开了一种减小感压薄膜焊接应力的电容压力传感器,通过增加了感压薄膜专用机架,并将感压薄膜与感压薄膜专用机架独立焊接,独立结构的感压薄膜机架与上下机架体接触部分少,受到机架体的热冲击及机械振动影响较小,因此消除了传统结构感压薄膜与机架之间的二次焊接应力,改善了因机械应力、温度等引起的感压薄膜与金属外壳之间的应力对测量的影响,显著减小了感压薄膜与金属外壳边缘之间产生的寄生电容,提高了电容薄膜压力计测量精度。(The invention discloses a capacitance pressure sensor for reducing welding stress of a pressure sensing film, which is characterized in that a special rack for the pressure sensing film is additionally arranged, the pressure sensing film is independently welded with the special rack for the pressure sensing film, the contact part of the pressure sensing film rack with an independent structure with an upper rack body and a lower rack body is less, and the influence of thermal shock and mechanical vibration of the rack bodies is less, so that secondary welding stress between the pressure sensing film and the rack with the traditional structure is eliminated, the influence of stress between the pressure sensing film and a metal shell caused by mechanical stress, temperature and the like on measurement is improved, parasitic capacitance generated between the pressure sensing film and the edge of the metal shell is remarkably reduced, and the measurement precision of a capacitance film pressure meter is improved.)

1. A capacitive pressure transducer for reducing weld stress in a pressure sensitive membrane, comprising: the device comprises a leading-out electrode rod (1), a bottom plate (2), a reference chamber (3), a hoop (4), a fixed electrode (5), a pressure sensing film (6), a special machine frame (7) for the pressure sensing film, a lower machine frame (8), a measuring cavity air inlet (9), a measuring chamber (10) and an upper machine frame (11);

the inner part of the upper frame (11) is of a step-shaped structure with a wide upper part and a narrow lower part, a limiting clamping table is formed at the step, the outer side of the lower surface of the fixed electrode (5) lapped with the limiting clamping table corresponds to the limiting clamping table in shape, the bottom plate (2) and the hoop (4) enable the fixed electrode (5) to be hermetically connected with the inner part of the upper frame (11), and the bottom plate (2) is fixedly connected with an opening at the upper end of the upper frame (11); the base plate (2), the clamp (4) and the fixed electrode (5) form the reference chamber (3); the reference chamber (3) has an air inlet that penetrates the base plate (2); the fixed electrode (5) is provided with the extraction electrode rod (1) penetrating through the bottom plate (2);

the outer side of the special pressure-sensitive film rack (7) is of a step-shaped structure with a narrow upper part and a wide lower part, the wider outer wall of the special pressure-sensitive film rack (7) is hermetically connected with the inner part of the lower rack (8), one end of the special pressure-sensitive film rack (7) with the wider outer wall is hermetically connected with the inner wall at the bottom end of the lower rack (8), one end of the special pressure-sensitive film rack (7) with the narrower outer wall is welded with the pressure-sensitive film (6), and the lower rack (8) is provided with the measuring cavity air inlet (9); the inner walls of the pressure sensing film (6), the special machine frame (7) for the pressure sensing film and the lower machine frame (8) form the measuring chamber (10);

the upper frame (11) is connected with the lower frame (8) in a welding mode.

2. Capacitive pressure sensor according to claim 1, characterized in that the pressure sensing membrane (6) is made of an alloy material.

3. Capacitive pressure sensor according to claim 2, characterized in that the pressure sensing membrane (6) is made of Inconel600 alloy.

4. Capacitive pressure sensor according to claim 2, characterized in that the pressure sensing membrane (6) is made of 3J58 alloy.

5. Capacitive pressure sensor according to claim 1, characterized in that the upper chassis (11) and the lower chassis (8) are made of a metallic material.

Technical Field

The invention belongs to the technical field of mechanical design and vacuum measurement, and particularly relates to a capacitance pressure sensor for reducing welding stress of a pressure-sensitive film.

Background

The capacitance film vacuum gauge is an instrument which utilizes the elastic diaphragm to produce displacement under the action of pressure difference to produce change of distance between electrode and diaphragm so as to change capacitance, and utilizes the change of measured capacitance to implement vacuum measurement. The method has the advantages of high measurement accuracy, good linearity, good output repeatability and long-term stability, capability of measuring the total pressure of gas and steam, independence of measurement results on gas components and types and the like, and is widely applied to the fields of vacuum measurement, microelectronic industry, surface treatment, plasma measurement, aerospace, high-energy physics, controllable thermonuclear fusion and the like. The capacitance pressure sensor is a physical unit of the capacitance film vacuum gauge, welding stress, mechanical vibration and thermal shock of the capacitance pressure sensor are main factors influencing processing and use of the capacitance pressure sensor, and the welding stress, the mechanical vibration and the thermal shock of the capacitance film pressure sensor in the manufacturing and using processes can deform a rack body, so that the pressure sensing film deforms, and nominal distance between the fixed electrode plate and the pressure sensing film changes to influence measurement accuracy.

Welding stress is a main factor influencing the processing and the use of the capacitive pressure sensor, and the welding stress of the capacitive pressure sensor in the manufacturing and using processes directly deforms the pressure sensing film, so that the nominal distance between the electrode plate and the film is changed, and the measurement precision is influenced. The pressure sensing film in the traditional capacitive pressure sensor must be welded for the second time, namely the pressure sensing film is welded on the lower frame firstly and then is welded with the upper frame again. The disadvantage of this design is that the secondary welding has a significant effect on the pressure sensing diaphragm, which can cause further deformation of the pressure sensing diaphragm, resulting in relative displacement between the pressure sensing diaphragm and the frame. In addition, the pressure sensing film is welded between the upper frame and the lower frame, parasitic capacitance is introduced between the edge of the pressure sensing film and the frames, and the caused change of the parasitic capacitance further affects the measurement precision, thereby affecting the measurement accuracy.

Disclosure of Invention

In view of this, the present invention provides a capacitive pressure sensor for reducing welding stress of a pressure-sensitive film, which can effectively reduce deformation of the pressure-sensitive film caused by secondary welding stress of a conventional capacitive film vacuum gauge, reduce the influence of parasitic capacitance at the edge of the pressure-sensitive film on measurement, and maintain the position stability of the pressure-sensitive film for a long time, thereby improving measurement accuracy and precision.

The invention provides a capacitance pressure sensor for reducing welding stress of a pressure sensing film, which comprises: the device comprises a leading-out electrode rod, a bottom plate, a reference chamber, a clamp, a fixed electrode, a pressure-sensitive film, a special machine frame for the pressure-sensitive film, a lower machine frame, a measurement cavity air inlet, a measurement chamber and an upper machine frame;

the inner part of the upper frame is of a step-shaped structure with a wide upper part and a narrow lower part, a limiting clamping table is formed at the step, the outer side of the lower surface of the fixed electrode, which is lapped with the limiting clamping table, corresponds to the shape of the limiting clamping table, the bottom plate and the hoop enable the fixed electrode to be hermetically connected with the inner part of the upper frame, and the bottom plate is fixedly connected with an opening at the upper end of the upper frame; the bottom plate, the clamp and the fixed electrode form the reference chamber; the reference chamber has an air inlet through the floor; the fixed electrode is provided with the leading-out electrode rod penetrating through the bottom plate;

the outer side of the special pressure-sensitive film rack is of a step-shaped structure with a narrow upper part and a wide lower part, the wider outer wall of the special pressure-sensitive film rack is hermetically connected with the inside of the lower rack, one end of the special pressure-sensitive film rack, which is provided with the wider outer wall, is hermetically connected with the inner wall of the bottom end of the lower rack, one end of the special pressure-sensitive film rack, which is provided with the narrower outer wall, is welded with the pressure-sensitive film, and the lower rack is provided with a gas inlet of the measurement cavity; the pressure sensing film, the special machine frame for the pressure sensing film and the inner wall of the lower machine frame form the measuring chamber;

the upper frame is connected with the lower frame in a welding mode.

Further, the pressure-sensitive film is made of an alloy material.

Further, the pressure-sensitive film is made of Inconel600 alloy.

Further, the pressure-sensitive film is made of 3J58 alloy.

Further, the upper frame and the lower frame are made of metal materials.

Has the advantages that:

according to the invention, the special rack for the pressure sensing film is added, the pressure sensing film is independently welded with the special rack for the pressure sensing film, the contact part between the pressure sensing film rack with an independent structure and the upper and lower rack bodies is less, and the influence of thermal shock and mechanical vibration of the rack bodies is less, so that the secondary welding stress between the pressure sensing film and the rack with the traditional structure is eliminated, the influence of stress between the pressure sensing film and the metal shell caused by mechanical stress, temperature and the like on measurement is improved, the parasitic capacitance generated between the pressure sensing film and the edge of the metal shell is obviously reduced, and the measurement precision of the capacitance film pressure gauge is improved.

Drawings

Fig. 1 is a schematic structural diagram of a capacitive pressure sensor for reducing welding stress of a pressure-sensitive film according to the present invention.

The device comprises a base plate, a pressure sensing film, a measuring cavity, a measuring electrode, a reference cavity, a clamp, a fixed electrode, a pressure sensing film, a special machine frame for the pressure sensing film, a lower machine frame, a measuring cavity air inlet, a measuring cavity and an upper machine frame, wherein 1-the leading-out electrode rod, 2-the base plate, 3-the reference cavity, 4-the clamp, 5-.

Detailed Description

The invention is described in detail below by way of example with reference to the accompanying drawings.

The invention provides a capacitance pressure sensor for reducing welding stress of a pressure sensing film, which has a structure shown in figure 1 and specifically comprises the following components: the device comprises a leading-out electrode rod 1, a bottom plate 2, a reference chamber 3, a hoop 4, a fixed electrode 5, a pressure sensing film 6, a special machine frame 7 for the pressure sensing film, a lower machine frame 8, a measurement cavity air inlet 9, a measurement chamber 10 and an upper machine frame 11.

The extraction electrode rod 1, the bottom plate 2, the hoop 4, the fixed electrode 5 and the upper frame 11 form the upper half part of the capacitive pressure sensor, the upper frame 11 is in a step-shaped structure with a wide top and a narrow bottom, a limiting clamping table is formed at a step, the outer side of the lower surface of the fixed electrode 5, which is in lap joint with the limiting clamping table, corresponds to the limiting clamping table in shape, the bottom plate 2 and the hoop 4 limit the position of the fixed electrode 5 along the axial direction of the upper frame 11, the fixed electrode 5 is hermetically connected with the inside of the upper frame 11, and the bottom plate 2 is fixedly connected with an opening at the upper end of the upper frame 11. The base plate 2, the clamp 4 and the fixed electrode 5 form a reference chamber 3, and the reference chamber 3 is provided with an air inlet penetrating through the base plate 2; the fixed electrode 5 has an extraction electrode rod 1 penetrating the base plate 2.

Pressure sensing film 6, special frame 7 of pressure sensing film, lower carriage 8, measure chamber air inlet 9, and last frame 11 constitutes capacitive pressure sensor's the latter half, the outside of special frame 7 of pressure sensing film is the step-like structure of narrow width down, the broad outer wall of special frame 7 of pressure sensing film and the inside sealing connection of lower carriage 8, the one end that special frame 7 of pressure sensing film has the broad outer wall and 8 bottom inner walls sealing connection of lower carriage, the one end that special frame 7 of pressure sensing film has the narrower outer wall and pressure sensing film 6 sealing connection, lower carriage 8 sets up the through-hole and is just measuring chamber air inlet 9. The pressure sensing film 6, the special frame 7 for the pressure sensing film and the inner wall of the lower frame 8 form a measuring chamber 10.

The upper frame 11 is hermetically connected with the lower frame 8.

The pressure-sensing film of the capacitive pressure sensor for reducing the welding stress of the pressure-sensing film is generally made of a high-elasticity alloy material, such as Inconel600 alloy nickel-chromium-iron-based solid solution strengthened alloy or 3J58 elastic alloy; the frame body is made of metal material, and is generally the same as the pressure-sensitive film material.

According to the capacitive pressure sensor for reducing the welding stress of the pressure sensing film, in the installation process, the pressure sensing film is independently welded on the special rack, and the pressure sensing film is only welded with the special rack once. And welding the special frame welded with the pressure sensing film with the lower sensor frame, and welding the lower sensor frame with the upper sensor frame to complete the assembly of the sensor.

In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.