CN201476927U

CN201476927U - Air pressure sensor

Info

Publication number: CN201476927U
Application number: CN2009202275022U
Authority: CN
Inventors: 李既浩; 王运斌; 廖景昌
Original assignee: XIANGFAN MEIRUI AUTOMOTIVE SENSOR CO Ltd
Current assignee: XIANGFAN MEIRUI AUTOMOTIVE SENSOR CO Ltd
Priority date: 2009-08-11
Filing date: 2009-08-11
Publication date: 2010-05-19
Anticipated expiration: 2019-08-11

Abstract

An air pressure sensor is characterized in that an inner cavity of a connection piece is provided with a press ring, the press ring is in interference fit with the connection piece, a sensitive element assembly is mounted in the inner cavity of the connection piece and on the lower end of the press ring, a boss is arranged on the connection piece, a limit step which corresponds to the boss is arranged on the press ring, the sensitive element assembly is connected with an end button arranged on the upper end of the connection piece through connected wires, a pressure medium input hole which is communicated with the inner cavity is arranged on the connection piece, a basal plate of the sensitive element assembly is an epoxy glass-fiber plate, and a bridge chip is adhesively arranged on the epoxy glass-fiber plate. In the utility model, the input and output characteristics are defined according to requirements of different users, the sensor can accurately measure the air pressure of an automobile pneumatic brake system and monitor the pressure of an automobile air inlet manifold, and the sensor is applicable to quantity production. The sensor has the advantages of high precision, good consistency, good stability, long service life, low cost and the like.

Description

Air pressure probe

Technical field

The utility model belongs to the pressure transducer technical field, is specifically related to the device that a kind of automatic measured automobiles gas is stopped system air pressure and can be reported to the police automatically.

Background technology

At present, be installed in the pressure transducer that Automobile air stops in the system and substantially all be based on a kind of mechanical structure, acted on diaphragm by measuring pressure, deformation takes place the latter is subjected to displacement the push rod that is attached thereto, along with push rod is subjected to displacement, the contact that links to each other with push rod slides into the relevant position to export corresponding resistance value on the thick-film resistor plate.This mechanical compression sensor is owing to exist hysterisis error, defective such as have that precision is low, consistance is poor, poor stability, serviceable life are low.Along with the enforcement of Europe three standards, requiring stops that system air pressure carries out high-precision reliable monitoring and cross at air pressure Automobile air in time provides alerting signal when low, to guarantee automobile braking safety.

Summary of the invention

For overcoming the defective of existing machinery formula pressure transducer, the utility model provides a kind of accurately measured automobiles gas stop system air pressure and the air pressure probe with precision height, high conformity, good stability, long service life.

In order to reach the foregoing invention purpose, technical solution of the present utility model is: a kind of air pressure probe, and the web member inner chamber has pressure ring, pressure ring and web member interference fit, the sensitive element assembly is loaded on web member inner chamber, pressure ring lower end; The sensitive element assembly connects through being connected lead with the terminal of web member upper end; Pressure medium input hole with its intracavity inter-connection is arranged on the web member.

Between the utility model sensitive element assembly and the web member rubber washer is arranged.Between pressure ring and the web member rubber washer is arranged.

Sensitive element assembly substrate is an epoxy glass plate, and the electric bridge die bonding is to epoxy glass plate.

Sensitive element assembly of the present utility model comprises with by the measuring pressure size variation and the electric bridge chip that the brachium pontis voltage dependent resistor (VDR) of proportional variation is formed; The signal of a reception electric bridge chip, processing back are by signal output part S output and by the process chip of the big or small corresponding magnitude of voltage of measuring pressure; External power supply V is connected to process chip and electric bridge chip power supply end after by field effect transistor FET1 voltage stabilizing, and field effect transistor FET2 is arranged on the circuit ground end.

Sensitive element assembly process chip described in the utility model is for providing transducing signal skew, sensitivity, temperature drift, the bridge type magnetic sensor signal processing chip of nonlinear digital compensation function and sensing calibration function by embedded micro-processor operation correcting algorithm.

The utility model can define input-output characteristic according to the requirement of different user, also promptly under the constant prerequisite of product structure, can come correlation parameter in the process chip is write according to tested pressure limit and corresponding output valve, to satisfy its output characteristics.The utility model operating temperature range broad can be worked under-40 ℃～+ 150 ℃ environment in addition.

The utility model is the measured automobiles gas system air pressure of stopping accurately, be suitable for producing in enormous quantities, have advantages such as precision height, high conformity, good stability, long service life, low cost, the utility model is applicable to that the Automobile air system pressure of stopping monitors automatically, also can be used for the automobile inlet manifold pressure monitoring.

Description of drawings

The utility model will be further described below in conjunction with accompanying drawing.

Fig. 1 is an one-piece construction synoptic diagram of the present utility model.

Fig. 2 is the vertical view of Fig. 1.

Fig. 3 is a sensitive element assembly contour structures synoptic diagram.

Fig. 4 is the circuit theory diagrams of sensitive element assembly.

Embodiment

Among Fig. 1, Fig. 2, pressure measurement cell is sensitive element assembly (6), this pressure measurement cell is by pressure medium input hole (9) the input pressure medium on the metal connecting piece (2), placed a rubber washer (7) between sensitive element assembly (6) and the web member (2), pressure ring (4) is taked interference fit with web member (2), can be pressed into by hydropress 3～4MPa pressure.Web member has boss on (2), the limited step corresponding with boss (14) arranged on the pressure ring (4), can weigh or damage by pressure sensitive element assembly (6) wounded to prevent pressure ring (4) in that to guarantee that pressure ring (4) carry out under the prerequisite of an amount of compressing rubber packing ring (7) assurance sealing by sensitive element assembly (6) bearing substrate epoxy glass plate spacing by this step (14).Terminal (1) has 3 inserted sheets, and inserted sheet one (10) is a power cathode, and inserted sheet two (11) is a positive source, and inserted sheet three (12) is the signal output stage, and inserted sheet polarity can arbitrarily define according to customer requirements.Sensitive element assembly (6) connect by three that leads (5) are realized and terminal (1) between be electrically connected, be placed with rubber washer (3) above the pressure ring (4), by the web member flange is handled terminal (1) is firmly pushed down on rubber washer (3), can prevent that sealing or dust enter so on the one hand, help improving reliability of products and degree of protection, can prevent that on the other hand pressure ring in the use (4) from axial float taking place and cause the seal failure of rubber washer (7).For improving sensitive element assembly (6) heat dispersion and barrier propterty, the upward good silica gel (13) of embedding one deck heat conductivility of sensitive element assembly (6) can improved.(8) for screw thread is installed.

Among Fig. 3, epoxy glass plate (15) is as components and parts and pressure bearing substrate, must possess certain intensity and thickness, consider cost and applicability principle, can preferentially select the printed board of epoxy glass, as FR-4 etc., if cost does not have problems, also can select extraordinary base material printed board for use, as metal base (aluminium base, copper base, iron-based or invar steel), ceramic base material.Electric bridge chip (21) bonds on the epoxy glass plate (15) by a kind of flexible flexible glue, being electrically connected by spun gold or aluminium wire bonding between the two.After electric bridge chip (21) bonding is good guard circle bonded to epoxy glass plate (15); as shown in Figure 3; be the protection chip; inject gel (20) in the guard circle; this gel (20) adopts the two-component silicone rubber gel; it has a less viscosity in A, B component after mixing soon, and just can reach desired viscosity, hardness or elasticity through preset time after A, B component are mixed.To epoxy glass plate (15), whole process must be taked strict antistatic countermeasure by Reflow Soldering or manual welding paster for other components and parts resistance R 1 (16), capacitor C 1 (17), field effect transistor FET1 (18), capacitor C 2 (22), process chip (23), field effect transistor FET2 (24).(19) be guard circle, (25) are electric bridge chip pressure medium input hole, and (26) are epoxy glass plate pressure medium input hole.

Among Fig. 4, Rs1, Rs2, Rs3, Rs4 are that electric bridge chip (21) is gone up the brachium pontis voltage dependent resistor (VDR), its resistance value is with by the measuring pressure size variation and proportional variation, this change by process chip (23) chip handle the back by signal output part S output with by the corresponding magnitude of voltage of measuring pressure size.External power supply V is connected to process chip (23) and electric bridge chip (21) feeder ear after by field effect transistor FET1 (18) voltage stabilizing; when V changes; process chip (23) can be passed through FEEDBACK CONTROL effect pipe FET1 (18) grid, to reach the effect of voltage stabilizing and overvoltage protection.Field effect transistor FET2 (24) is placed on circuit ground end G, plays the effect of reversal of power protection.Filter capacitor C1 (17), C2 (22) are connected in parallel on external power supply end V and process chip (23) and electric bridge chip (21) feeder ear respectively, the signal output part resistance R 1 (16) of connecting, and the R1 resistance is less, plays the overcurrent protection effect.Electric bridge chip (21) is a silicon micro mechanical piezoresistive transducer chip, can be directly installed on the epoxy glass plate.Process chip (23) is a high precision bridge type magnetic sensor signal processing chip.Circuit ground end G is connected with the power cathode of terminal, and signal output part S is connected with the signal output stage of terminal, and external power supply V is connected with the positive source of terminal.

Claims

1. air pressure probe, it is characterized in that: web member (2) inner chamber has pressure ring (4), and sensitive element assembly (6) is loaded on web member (2) inner chamber, pressure ring (4) lower end; Sensitive element assembly (6) connects through being connected lead (5) with the terminal (1) of web member (2) upper end; Pressure medium input hole (9) with its intracavity inter-connection is arranged on the web member (2).

2. air pressure probe according to claim 1 is characterized in that: said sensitive element assembly (6) substrate is an epoxy glass plate (15), and electric bridge chip (21) bonds on the epoxy glass plate (15).

3. air pressure probe according to claim 1 is characterized in that: boss (14) is arranged on the said web member (2), have on the pressure ring (4) and the corresponding limited step of boss (14).

4. air pressure probe according to claim 1 is characterized in that: between sensitive element assembly (6) and web member (2) rubber washer (7) is arranged.

5. air pressure probe according to claim 1 is characterized in that: between said pressure ring (4) and the web member (2) rubber washer (3) is arranged.

6. air pressure probe according to claim 1, it is characterized in that: said terminal (1) have 3 respectively with the inserted sheet that lead is connected that is connected of sensitive element assembly (6), an one inserted sheet is a power cathode, and an inserted sheet is a positive source, and an inserted sheet is the signal output stage.

7. air pressure probe according to claim 1 is characterized in that: said sensitive element assembly (6) comprises with by the measuring pressure size variation and the electric bridge chip (21) that the brachium pontis voltage dependent resistor (VDR) of proportional variation is formed; The signal of a reception electric bridge chip (21), processing back are by signal output part S output and by the process chip (23) of the big or small corresponding magnitude of voltage of measuring pressure; External power supply V is connected to process chip (23) and electric bridge chip (21) feeder ear by field effect transistor FET1 (18), and field effect transistor FET2 (24) is arranged on the circuit ground end.

8. air pressure probe according to claim 7, it is characterized in that: said process chip (23) is for providing the transducing signal skew by embedded micro-processor operation correcting algorithm, sensitivity, temperature drift, the bridge type magnetic sensor signal processing chip of nonlinear digital compensation function and sensing calibration function.

9. air pressure probe according to claim 7, it is characterized in that: said sensitive element assembly (6), there are filter capacitor C1 (17), C2 (22) to be connected in parallel on external power supply V and process chip (23) and electric bridge chip (21) feeder ear respectively, the signal output part S resistance R 1 of connecting.

10. air pressure probe according to claim 7, it is characterized in that: the circuit ground end of said sensitive element assembly (6) is connected with the power cathode of terminal (1), the signal output part S of sensitive element assembly (6) is connected with the signal output stage of terminal (1), and the external power supply V of sensitive element assembly (6) is connected with the positive source of terminal (1).