JPH0676634U - Diaphragm actuator with linear displacement sensor - Google Patents

Abstract

(57) [Summary] [Structure] The diaphragm 2 is fixed between the housing halves 1A and 1B of the housing 1. A core 72 made of a magnetic material is fixed to the diaphragm 2. A supporting portion 71 is integrally formed with the housing half body 1B. Detection coils 76 and 77 for detecting the position of the core 72 are attached to the support portion 71. [Effect] The positional accuracy of the core 72 and the detection coils 76 and 77 can be improved, and thus the detection accuracy of the sensor unit 7 can be improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a diaphragm type actuator suitable for use in adjusting the opening degree of an EGR (exhaust gas recirculation) valve.

[0002]

[Prior art]

 Generally, an EGR valve is used in an EGR control system of an engine, and a diaphragm actuator is used to adjust the opening degree of the EGR valve. In this diaphragm type actuator, the inside of the housing is divided by a diaphragm into first and second chambers, the first chamber is connected to an intake system, and the second chamber is opened to the atmosphere. The diaphragm is connected to the valve body of the EGR valve. Therefore, when the diaphragm is displaced according to the change of the intake pressure, the valve body of the EGR valve is opened and closed accordingly, and the opening degree of the EGR valve is adjusted according to the displacement amount of the diaphragm. There is.

By the way, when the operating state of the engine is controlled by a computer, it is desirable to feed back the opening degree of the EGR valve. Therefore, in the conventional diaphragm type actuator, a displacement member is attached to the diaphragm, and a linear displacement sensor is attached to the housing, and the displacement amount of the displacement member is detected by this linear displacement sensor, which in turn detects the opening degree of the EGR valve. (See Japanese Utility Model Laid-Open No. 3-114004).

[0004]

[Problems to be solved by the device]

 However, the conventional diaphragm-type actuator with a linear displacement sensor has a problem that the detection accuracy varies among the actuators. That is, the conventional diaphragm type actuator with a linear displacement sensor is manufactured by individually manufacturing the diaphragm type actuator and the linear displacement sensor, and then assembling the two. However, both have manufacturing errors, and when they are assembled, the manufacturing errors of both are added. As a result, the positional accuracy between the displacement member attached to the diaphragm and the detection part of the sensor deteriorated, and the detection accuracy among the actuators varied.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention divides the inside of a housing into a first chamber and a second chamber, and displaces the housing in accordance with a pressure difference between the first chamber and the second chamber. Diaphragm actuator with a linear displacement sensor, which includes a diaphragm, a displacement member attached to the diaphragm, which is linearly displaced according to the displacement of the diaphragm, and a displacement amount detection unit which detects the displacement amount of the displacement member. In the above, the support part for supporting the displacement amount detection part is formed integrally with the housing.

[0006]

[Action]

 Since the housing and the support portion of the displacement detector are integrally formed, the positional accuracy between the displacement member and the displacement detector can be improved. Therefore, it is possible to suppress variations in detection accuracy among the actuators.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows an embodiment in which a diaphragm type actuator with a linear displacement sensor according to this idea is applied to an EGR valve, and reference numeral 1 is a housing. The housing 1 is composed of two housing halves 1A and 1B each having a short tube shape and having a bottom.

One of the housing half bodies 1A is formed by press-molding a metal plate, and a flange portion 11 is formed at an upper end opening portion thereof, and a caulking portion 12 is formed outside the flange 11. Has been done. An opening 13 is formed on the outer periphery of the lower end of the housing half 1A.

The other housing half 1B is made of resin and is formed by an injection molding method or the like. A flange portion 14 having the same diameter as the flange portion 11 is formed in the lower end opening of the housing 1B, a connection port 15 connected to the intake system of the engine is formed on the outer periphery of the upper end portion, and the upper surface will be described later. The supporting portion 71 of the sensor unit 7 is integrally formed.

The two halves 1A and 1B are integrated by crimping the crimp portion 12 with the peripheral edge portion of the diaphragm 2 sandwiched between the flange portions 11 and 14 of each other. 1 is formed. Therefore, the inner portion of the housing 1 is divided by the diaphragm 2 into the atmospheric pressure chamber (first chamber) 3 on the half body 1A side and the negative pressure chamber (second chamber) 4 on the half body 1B side. The atmospheric pressure chamber 3 is opened to the atmosphere through an opening port 13, and the negative pressure chamber 4 is connected to an intake system through a connection port 15. When the negative pressure in the negative pressure chamber 4 increases and the differential pressure between the atmospheric pressure chamber 3 and the negative pressure chamber 4 exceeds a predetermined value, the diaphragm 2 resists the biasing force of the spring 5 and moves toward the half body 1B side. It is designed to be displaced.

A valve body 61 of the EGR valve 6 is fixed to a central portion of the lower surface of the half body 1A via a screw portion 16. The valve body 61 is formed between an introduction port 62 to which exhaust gas is supplied from the exhaust system of the engine, a discharge port 63 connected to the intake system of the engine, and the introduction port 62 and the discharge port 63. A valve seat 64 is provided, and both ports 62 and 63 are opened and closed by a valve body 65.

That is, the upper end portion of the valve body 65 is fixed to the diaphragm 2 via the support plate 21. The valve body 65 penetrates the half body 1A and slidably and airtightly penetrates the screw portion 17 to extend inside the valve body 61, and a valve portion 65a is formed at a lower end portion thereof. . When the pressure difference between the atmospheric pressure chamber 3 and the negative pressure chamber 4 is less than or equal to a predetermined value, the valve portion 65a is seated on the valve seat 64 by the urging force of the spring 5, and the space between the ports 62 and 63 is reduced. Although it is shut off, when the pressure difference between the atmospheric pressure chamber 3 and the negative pressure chamber 4 exceeds a predetermined value, the diaphragm 2 lifts from the valve seat 64 along with the displacement, and the ports 62 and 63 are opened. It is like this.

A sensor section 7 is provided at the center of the upper surface of the half body 1B of the housing 1. That is, the support portion 71 is integrally formed on the upper surface of the half body 1B. The support portion 71 has a tubular shape with an upper end closed, and a core (displacement member) 72 made of a magnetic material is movably inserted therein. The core 72 is fixed to the diaphragm 2 via a shaft 73 and a support plate 22. Therefore, when the valve body 65 is lifted from the valve seat 64, the core 72 moves by a distance equal to the lift amount.

On the outer circumference of the support 71, two annular recesses 74 and 75 are formed vertically separated from each other. Detection coils (displacement amount detection units) 76 and 77 are wound around the annular recesses 74 and 75, and the displacement amounts of the core 72 are detected by the detection coils 76 and 77 based on a known method. There is.

In the diaphragm type actuator having the above structure, the support portion 71 on which the coils 76 and 77 of the sensor portion 7 are to be wound is formed integrally with the half body 1B of the housing 1, and the diaphragm 2 that displaces the core 72 is also half. Since it is fixed to the body 1B, the position between the core 72 and the detection coils 76, 77 is different from that of the conventional actuator in which the diaphragm type actuator and the displacement sensor are manufactured separately and assembled together. The accuracy can be improved. Therefore, it is possible to prevent the detection accuracy from varying among the actuators.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the invention. For example, in the above embodiment, the displacement amount of the core 72 is detected by the detection coils 76 and 77, but it may be detected by the method described in Japanese Utility Model Laid-Open No. 3-114004. May be. Further, in the above embodiment, the pressure of the atmospheric pressure chamber 3 as the first chamber is set to be higher than the pressure of the negative pressure chamber 4 as the second chamber, but it may be reversed. Further, the diaphragm type actuator with the linear displacement sensor can be applied to other than the EGR valve.

[0017]

[Effect of device]

 As described above, according to the diaphragm type actuator with the linear displacement sensor of the present invention, the support portion for supporting the displacement amount detecting portion is integrally formed with the housing, so that the displacement amount detecting portion and the diaphragm are fixed. It is possible to improve the positional accuracy with respect to the displacing member. Therefore, it is possible to prevent the detection accuracy from varying among the actuators.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1 Housing 1A Housing half body 1B Housing half body 2 Diaphragm 3 Atmospheric pressure chamber (first chamber) 4 Negative pressure chamber (second chamber) 7 Sensor part 71 Support part 72 Core (displacement member) 76 Detection coil (displacement amount) Detection unit) 77 Detection coil (displacement amount detection unit)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location G01B 7/00 B 9106-2F

Claims (1)

[Scope of utility model registration request] 1. A diaphragm which divides the inside of a housing into a first chamber and a second chamber, and which is displaced according to a pressure difference between the first chamber and the second chamber, and a diaphragm attached to this diaphragm. In a diaphragm actuator with a linear displacement sensor, which includes a displacement member that linearly displaces following the displacement of the diaphragm and a displacement amount detection unit that detects the displacement amount of the displacement member, the displacement amount detection unit is supported. A diaphragm type actuator with a linear displacement sensor, characterized in that a supporting portion is formed integrally with the housing.