JP2004183507A - Diaphragm type actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate torn of a spring support washer even by regulation of a coiled spring by an adjusting bolt, in a diaphragm type actuator in which the coil spring for energizing a diaphragm to the side for reducing the volume of a pressure chamber is contained in a spring chamber formed in the cylindrical portion of a supporting case, and the spring support washer for supporting the coiled spring is brought into contact with the adjusting bolt engaged with the cylindrical portion so as to adjust the spring force of the coiled spring. <P>SOLUTION: A diamond-like carbon layer 134 is formed on the surface of the spring support washer 130. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a diaphragm-type actuator, and in particular, a peripheral portion of a diaphragm that applies fluid pressure in a pressure chamber to one surface is sandwiched by a support case, and a spring chamber facing the other surface of the diaphragm is a part of the support case. A coil spring formed in the cylindrical portion and urging the diaphragm toward the side for reducing the volume of the pressure chamber is housed in the spring chamber, and a spring receiving washer for receiving the coil spring is provided by the spring of the coil spring. The present invention relates to an improvement of a diaphragm type actuator which is brought into contact with an adjustment bolt screwed to the cylindrical portion to adjust a force.
[0002]
[Prior art]
Such a diaphragm-type actuator is already known, for example, from Patent Document 1 below.
[0003]
[Patent Document 1]
JP-A-11-270716
[Problems to be solved by the invention]
By the way, the adjusting bolt is for adjusting the spring force of the coil spring, and the adjusting bolt is tightened or loosened during assembly to adjust the spring force of the coil spring. An event occurs in which the spring receiving washer is bitten at the end of the coil spring, and it may not be possible to readjust the spring. This causes a reduction in product yield. In addition, chips may be generated by the spring receiving washer being bitten, and the ends of the coil spring may ride on the chips, which may lower the operating accuracy of the diaphragm.
[0005]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a diaphragm actuator in which a spring receiving washer is prevented from being bitten even by adjusting a spring force of a coil spring by an adjustment bolt.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that a peripheral portion of a diaphragm that applies fluid pressure of a pressure chamber to one surface is sandwiched by a support case, and the spring chamber facing the other surface of the diaphragm is the spring chamber. A coil spring that is formed in a cylindrical portion that constitutes a part of the support case and that urges the diaphragm to the side that reduces the volume of the pressure chamber is housed in the spring chamber, and a spring receiving washer that receives the coil spring, In a diaphragm type actuator that is brought into contact with an adjust bolt screwed into the cylindrical portion to adjust the spring force of the coil spring, a diamond-like carbon layer is formed on a surface of the spring receiving washer. Features.
[0007]
According to the structure of the first aspect of the present invention, the diamond-like carbon layer is a carbon thin film having a high hardness similar to diamond and exhibits excellent slidability and wear resistance. Therefore, it is possible to prevent the spring receiving washer from being bitten at the end of the coil spring when the adjusting bolt is rotated, thereby improving the product yield and preventing the generation of chips, thereby preventing the diaphragm from being chipped. Can be improved in operation accuracy.
[0008]
Further, according to the invention of claim 2, the peripheral portion of the diaphragm for applying the fluid pressure of the pressure chamber to one surface is sandwiched by the support case, and the spring chamber facing the other surface of the diaphragm constitutes a part of the support case. A coil spring that is formed in the cylindrical portion and that urges the diaphragm to the side that reduces the volume of the pressure chamber is housed in the spring chamber, and a spring receiving washer that receives the coil spring controls the spring force of the coil spring. In a diaphragm type actuator which is brought into contact with an adjustment bolt screwed into said cylindrical portion for adjustment, a silicon film or a chromium film and a diamond-like carbon covering the silicon film or the chromium film are provided on the surface of said spring receiving washer. And a layer is formed.
[0009]
According to the configuration of the second aspect of the invention, the silicon film has a coefficient of expansion substantially equal to that of the diamond-like carbon layer which is a carbon thin film, and the chromium film has excellent adhesion to the base material. In addition, the diamond-like carbon has excellent adhesion to the diamond-like carbon layer due to the anchoring effect between the diamond-like carbon and the carbide generated at the chromium film side boundary. Since the diamond-like carbon layer is formed so as to be interposed between the washer and the surface of the washer, it is possible to reliably form the diamond-like carbon layer on the surface of the spring receiving washer. In addition, the diamond-like carbon layer is a high-hardness carbon thin film similar to diamond and exhibits excellent slidability and wear resistance. Thus, the spring receiving washer can be prevented from being bitten, the product yield can be improved, and the operation accuracy of the diaphragm can be improved by preventing generation of chips.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0011]
1 to 8 show a first embodiment of the present invention. FIG. 1 is a view schematically showing a configuration of a fuel gas supply device, FIG. 2 is a longitudinal sectional view of a primary pressure reducing valve, and FIG. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3, FIG. 5 is an enlarged view of a main part of FIG. 2, and FIG. FIG. 7 is a diagram showing the part replacement ratio in comparison with the conventional one, and FIG. 8 is a diagram showing the flow rate variation of the primary pressure reducing valve in comparison with the conventional one.
[0012]
First, in FIG. 1, compressed natural gas (hereinafter, referred to as CNG) is stored in one or a plurality of CNG tanks 20 at a high pressure of, for example, 25 to 1 MPa, and the CNG tanks 20 are respectively stored. Are connected to the filling port 22 in common via a check valve 23 and are also connected in common to a manual shut-off valve 24, and a pipe between each container shut-off valve 21 and the manual shut-off valve 24 is provided. The path 25 is provided with a pressure sensor 26 and a temperature sensor 27.
[0013]
CNG from the CNG tanks 20 when the container shut-off valves 21 and the manual shut-off valves 24 are opened is an oil filter for removing oil that may be mixed when the CNG tanks 20 are filled with CNG by the compressor. CNG, which is led to a regulator RA via a high-pressure pipe 28 provided with a pressure regulator 29 and reduced to, for example, 0.6 to 0.7 MPa by the regulator RA, is led to a secondary pressure reducing valve 31 through a low-pressure filter 30, and The CNG pressure reduced to, for example, 0.2 to 0.3 MPa by the next pressure reducing valve 31 is led to the injector 32 of the engine E via the pipe 33, and the pipe 33 is provided with a temperature sensor 34 and a pressure sensor 35. Is done.
[0014]
The regulator RA includes a common regulator body 38 having a hot water passage 37, a high-pressure filter 39, an electromagnetic shut-off valve 40, and a primary pressure reducing valve 41, and a pressure switch 42 is attached to the regulator RA. .
[0015]
The high-pressure filter 39 removes impurities contained in CNG that is guided from the manual shut-off valve 24 via the high-pressure pipe 28. Further, the primary pressure reducing valve 41 operates to reduce the pressure of the high-pressure CNG of 25 to 1 MPa from which impurities have been removed by the high-pressure filter 39 to, for example, 0.6 to 0.7 MPa. It is interposed between the high-pressure filter 39 and the primary pressure-reducing valve 41 to shut off when the operation is stopped or when a signal is output from the pressure switch 42. Further, the pressure switch 42 changes the switching mode according to the pressure of the CNG depressurized by the primary pressure reducing valve 41 becoming, for example, a preset pressure, for example, 1.65 MPa or more, and a signal for shutting off the electromagnetic shutoff valve 40. Is output.
[0016]
Engine cooling water is introduced from the engine E into the hot water passage 37 of the regulator body 38 in order to prevent the temperature of the regulator body 38 from excessively lowering due to the pressure reducing operation of the primary pressure reducing valve 41. The thermostat 43 arranged separately from the regulator body 38 closes when the engine cooling water flowing through the hot water passage 37 exceeds, for example, 70 ° C., so that the temperature of the regulator body 38 does not rise excessively. I do.
[0017]
In FIG. 2, the primary pressure reducing valve 41 includes a diaphragm type actuator A and a valve unit V driven by the diaphragm type actuator A. The diaphragm type actuator A is configured such that a diaphragm 93 whose peripheral portion is sandwiched by the support case 90, a coil spring 116 interposed between the support case 90 and the diaphragm 93, and a part of the diaphragm type actuator A slides on the support case 90. A leaf spring 132 held at the center of the diaphragm 93. Further, the valve portion V includes a valve seat member 98 fixed to the regulator body 38, a valve body 106 that can be seated on the valve seat member 98, and a valve body 106 that is seated on the valve seat 105 of the valve seat member 98. A biasing spring 112.
[0018]
The support case 90 is composed of a regulator body 38 made of an aluminum alloy and an aluminum alloy cover 91 fastened to one end face 50 of the regulator body 38 with a plurality of bolts 92. A peripheral portion of a rubber diaphragm 93 is sandwiched between one end surface 50 and a cover 91 having a cylindrical portion 91a.
[0019]
On one end face 50 of the regulator body 38, a concave portion 95 is formed to form a decompression chamber 94 as a pressure chamber between itself and one face of the diaphragm 93. Is provided. The mounting hole 97 has a first hole 97a having one end opened at the center of the closed end of the concave portion 95, and a first hole 97a having a diameter smaller than that of the first hole 97a and one end coaxially connected to the other end of the first hole 97a. A second hole 97b, a third hole 97c having a diameter smaller than that of the second hole 97b and one end coaxially connected to the other end of the second hole 97b, and a third hole 97 having a diameter smaller than the third hole 97c. A fourth hole 97d having one end coaxially connected to the other end of the portion 97c, and a detection hole 136 for detecting the pressure on the output side of the primary pressure reducing valve 41 with the pressure switch 42 is coaxial with the fourth hole 97d. Are provided in the regulator body 38 in such a manner as to communicate with the regulator body 38. The passage 80 for guiding CNG from the electromagnetic shutoff valve 40 is provided in the regulator body 38 so as to open to the inner surface of the second hole 97b.
[0020]
A cylindrical valve seat member 98 is screwed into the first hole 97a of the mounting hole 97 so as to sandwich an annular seal member 99 between the first hole 97a and the step between the first and second holes 97a and 97b. Is done. That is, a female screw 100 is engraved on the inner surface on one end side of the first hole portion 97 a in the mounting hole 97, and the valve seat member 98 is screwed to the female screw 100.
[0021]
On the end face of the valve seat member 98 on the side of the decompression chamber 94, a plurality of, for example, four grooves 101 extending in the radial direction of the valve seat member 98 in a plane perpendicular to the axis of the mounting hole 97 are formed. Are formed so as to protrude, and the grooves 101 are arranged in a cross shape. When the valve seat member 98 is screwed into the female screw 100, a tool (not shown) can be engaged with the grooves 101 arranged in a cross shape to rotate the valve seat member 98. The member 98 can be easily attached to the regulator body 38.
[0022]
A valve chamber 103 communicating with the passage 80 is formed between the valve seat member 98 and a step between the second and third holes 97b and 97c in the mounting hole 97. Further, the valve seat member 98 integrally includes an inward flange 98a that protrudes inward in the radial direction at the end on the decompression chamber 94 side, and a valve that communicates with the decompression chamber 94 on the inner periphery of the inward flange 98a. A hole 104 is formed, and a tapered valve seat 105 facing the valve chamber 103 with the valve hole 104 opened at the center is formed on the inner surface of the inward flange 98a.
[0023]
A valve body 106 made of synthetic resin that can be seated on the valve seat 105 is housed in the valve chamber 103, and the valve body 106 is fixed to a valve shaft 107 arranged coaxially with the valve hole 104.
[0024]
The valve body 106 is formed in a cylindrical shape with one end face opposed to the valve seat 105 tapered so as to be seated on the tapered valve seat 105. By fixedly fitting, it is fixed to the valve shaft 107. Moreover, an O-ring 108 is mounted on the outer surface of the valve shaft 107 so as to resiliently contact the inner surface of the valve body 106.
[0025]
One end of the valve shaft 107 is axially movable by an O-ring 109 interposed between the mounting hole 97 and the inner surface of the third hole 97c, and is supported by the regulator body 38. Further, the outer surface of the valve body 106 is in sliding contact with the inner surface of the valve seat member 98 at a plurality of locations spaced at equal intervals in the circumferential direction, and between the sliding contact portions between the valve body 106 and the valve seat member 98. Are formed with flow passages 110 extending along the axial direction of the valve shaft 107.
[0026]
A holding plate 111 for holding the O-ring 109 between the mounting hole 97 and the step between the third and fourth holes 97c and 97d is provided between the second and third holes 97b and 97c. A spring 112 is provided between the holding plate 111 and the valve element 106 to exert a spring force in a direction in which the valve element 106 is seated on the valve seat 105.
[0027]
A spring chamber 115 that faces the other surface of the diaphragm 93 is formed between the cover 91 and the diaphragm 93, and a coil spring 116 that urges the diaphragm 93 toward the decompression chamber 94 is housed in the spring chamber 115.
[0028]
In the cylindrical portion 91a of the cover 91, a storage hole 117 extending coaxially with the valve hole 104 is provided so as to open the outer end, and the storage hole 117 is a screw hole portion 117a on the axially outward side. And a sliding hole 117b on the axially inward side coaxially connected to the screw hole 117a and having a diameter larger than that of the screw hole 117a.
[0029]
A first diaphragm retainer 118 having an integral cylindrical portion 118a penetrating the center of the diaphragm 93 and protruding toward the spring chamber 115 is in contact with a surface facing the decompression chamber 94 at the center of the diaphragm 93. On the surface facing the spring chamber 115 side of the central portion of 93, the inner periphery is engaged with an annular step portion 119 provided on the outer surface of the cylindrical portion 118a so that the central portion of the diaphragm 93 is located between the first diaphragm retainer 118 and the center portion. The sandwiched second diaphragm retainer 120 abuts.
[0030]
The other end of the valve shaft 107, that is, the end on the side of the diaphragm 93, is coaxially fastened to the diaphragm rod 121, and the diaphragm rod 121 is inserted into the center of the first diaphragm retainer 118 from the decompression chamber 94 side. . An annular step 122 facing the decompression chamber 94 is provided on the inner surface of the cylindrical section 118a of the first diaphragm retainer 118, and the diaphragm rod 121 is engaged with the annular step 122. The second diaphragm retainer 120 is sandwiched between the diaphragm 93 and the auxiliary retainer 123, and is provided between the auxiliary retainer 123 and a screw shaft portion 121a provided on the diaphragm rod 121 at a portion protruding from the cylindrical portion 118a. A nut 125 with a washer 124 interposed therebetween is screwed into the nut 125. By tightening the nut 125, the central portion of the diaphragm 93 is sandwiched between the two diaphragm retainers 118 and 120, and the valve shaft 107 is fixed to the central portion of the diaphragm 93. Will be. Moreover, in order to seal between the decompression chamber 94 and the spring chamber 115, the O-ring 126 mounted on the outer periphery of the diaphragm rod 121 resiliently contacts the inner surface of the cylindrical portion 118a.
[0031]
An adjustment bolt 127 made of an aluminum alloy is screwed into the opening at the outer end of the storage hole 117, that is, the screw hole 117 a so as to be able to advance and retreat, and a position where the adjustment bolt 127 advances and retreats is fitted to a projecting portion of the adjustment bolt 127 from the cover 91. A lock nut 128 for adjusting the pressure is screwed. The adjusting bolt 127 is provided with an opening 129 for opening the spring chamber 115 to the atmosphere.
[0032]
A coil spring 116 made of stainless steel, for example, SUS304 (JIS) is attached to the diaphragm 93 on the spring chamber 115 side with a spring receiving washer 130 made of stainless steel, for example, SUS304 (JIS), which comes into contact with the inner surface of the adjustment bolt 127. And a leaf spring 132 which is in contact with the auxiliary retainer 123. Therefore, the spring load of the coil spring 116 can be adjusted by adjusting the advance / retreat position of the adjustment bolt 127.
[0033]
Referring to FIGS. 3 and 4 together, the leaf spring 132 is for applying sliding resistance to the diaphragm 93 by making frictional contact with the inner surface of the cylindrical portion 91 a which is a part of the support case 90. A bottomed cylindrical cup portion 132a having a closed end sandwiched between an auxiliary retainer 123 and a coil spring 116 mounted on the center of the diaphragm 93 on the side of the spring chamber 115, and an inner surface of a sliding hole 117b in the cylindrical portion 91a. Are resiliently slidably contacted at a plurality of places, for example, eight places at equal intervals in the circumferential direction, and are integrally formed with a plurality of leaf parts 132b, 132b,. It is formed of stainless steel, for example, SUS304 (JIS).
[0034]
In the regulator body 38, a plurality of outlet passages 133, which allow one end to pass through the decompression chamber 94, are formed in parallel with the mounting holes 97. These outlet passages 133 are connected to the low-pressure filter 30 (see FIG. 1). You.
[0035]
In such a primary pressure reducing valve 41, when high-pressure CNG does not flow into the valve chamber 103, the diaphragm 93 is bent toward the pressure reducing chamber 94 by the spring force of the coil spring 116, and the valve body 106 is moved to the valve seat 105. And the valve hole 104 is opened. Thus, the high-pressure CNG flowing into the valve chamber 103 flows into the pressure reducing chamber 94 through the valve hole 104, and the pressure in the pressure reducing chamber 94 causes the diaphragm 93 to move toward the spring chamber 115 against the spring force of the coil spring 116. If it increases to the extent that it bends, the valve body 106 will sit on the valve seat 105 and the valve hole 104 will be closed. By repeatedly opening and closing such a valve hole 104, for example, 25 to 1 MPa The CNG that has flowed into the valve chamber 103 at a high pressure is reduced in pressure to, for example, 0.6 to 0.7 MPa, and flows from the decompression chamber 94 to the outlet passages 133.
[0036]
The adjusting bolt 127 is used to adjust the spring force of the coil spring 116, and adjusts the spring force of the coil spring 116 by tightening or loosening the adjusting bolt 127 during assembly. In order to prevent an event that the spring receiving washer 130 is bitten at the end of the coil spring 116 by the rotation operation of the adjusting bolt 127, the surface of the spring receiving washer 130 is, as shown in FIG. A like carbon layer 134 is formed. The diamond-like carbon layer 134 is a carbon thin film having a high hardness similar to diamond, and is formed to have a thickness of, for example, 0.2 to 10 μm. However, in FIG. 5, the diamond-like carbon layer 134 is exaggerated for the sake of simplicity.
[0037]
Next, the operation of the first embodiment will be described. In the diaphragm type actuator A of the primary pressure reducing valve 41, the diamond-like carbon layer 134 is formed on the surface of the spring receiving washer 130.
[0038]
Since the diamond-like carbon layer 134 is a carbon thin film having a high hardness similar to diamond and exhibits excellent slidability and wear resistance, the coil spring 116 is turned when the adjusting bolt 127 is rotated. The spring receiving washer 130 can be prevented from being bitten at the end of the diaphragm, the product yield can be improved, and the operation accuracy of the diaphragm can be improved by preventing generation of chips. .
[0039]
That is, when 100 diaphragm actuators A are assembled, for example, the rate at which the spring receiving washer 130 is bitten is, as shown in FIG. 6, the conventional one in which no surface treatment is applied to the spring receiving washer 130. In the present invention, it reaches 38%, whereas in the case of the present invention, it is 0%, so that it is possible to prevent an event that the spring receiving washer 130 becomes bitten.
[0040]
As shown in FIG. 7, the replacement rate of the spring receiving washer 130 caused by such a bite is, as shown in FIG. %, Which indicates that the product yield can be significantly improved. Further, as shown in FIG. 8, the flow rate variation in the primary pressure reducing valve 41 is significantly reduced to -1 to + 2% in the present invention, whereas it is in the range of -4 to + 5% for the conventional one. By preventing the generation of chips due to biting in the spring receiving washer 130, it is possible to prevent the coil spring 116 from climbing over the chips, thereby increasing the operation accuracy of the diaphragm type actuator A, and thus the primary pressure reducing valve. It can be seen that the flow control accuracy of 41 can be improved.
[0041]
In the first embodiment, the diamond-like carbon layer 134 is directly formed on the surface of the spring receiving washer 130. However, as in the second embodiment shown in FIG. A silicon film 135 and a diamond-like carbon layer 134 covering the silicon film 135 may be formed.
[0042]
The silicon film 135 has a coefficient of expansion substantially equal to that of the diamond-like carbon layer 134, which is a carbon thin film, and is formed to have a thickness in the range of 0.1 to 2 μm, for example. However, in FIG. 9, the diamond-like carbon layer 134 and the silicon film 135 are exaggerated in thickness for simplicity.
[0043]
According to the second embodiment, the diamond-like carbon layer 134 is formed so that the silicon film 135 having an expansion coefficient substantially equal to that of the diamond-like carbon layer 134 is interposed between the diamond-like carbon layer 134 and the surface of the spring receiving washer 130. As a result, the diamond-like carbon layer 134 can be reliably formed on the surface of the spring receiving washer 130.
[0044]
As another embodiment of the present invention, a chromium film may be used instead of the silicon film 135 in the above embodiment. In this case, the chromium film not only has excellent adhesion to the base material, but also has excellent adhesion to the diamond-like carbon layer 134 due to the anchoring effect between diamond-like carbon and carbide generated at the chromium film-side boundary. The diamond-like carbon layer 134 is formed on the surface of the spring receiving washer 130 by forming the diamond-like carbon layer 134 so that a chromium film is interposed between the surface of the spring receiving washer 130 and the surface of the spring receiving washer 130. It is possible to form it reliably.
[0045]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.
[0046]
【The invention's effect】
As described above, according to the first aspect of the present invention, it is possible to prevent the spring receiving washer from being bitten at the end of the coil spring when the adjusting bolt is turned, and to improve the product yield. As a result, the operation accuracy of the diaphragm can be improved by preventing the generation of chips.
[0047]
According to the second aspect of the present invention, the diamond-like carbon layer can be reliably formed on the surface of the spring receiving washer, and the spring is formed at the end of the coil spring when the adjusting bolt is rotated. The receiving washer can be prevented from being bitten, the product yield can be improved, and the operation accuracy of the diaphragm can be improved by preventing generation of chips.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of a fuel gas supply device.
FIG. 2 is a longitudinal sectional view of a primary pressure reducing valve.
FIG. 3 is a plan view of a leaf spring provided in the primary pressure reducing valve.
FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;
FIG. 5 is an enlarged view of a main part of FIG. 2;
FIG. 6 is a view showing the stiffness of a spring receiving washer in comparison with a conventional one.
FIG. 7 is a diagram showing a part replacement rate in comparison with a conventional one.
FIG. 8 is a diagram showing a flow rate variation of a primary pressure reducing valve in comparison with a conventional one.
FIG. 9 is a sectional view corresponding to FIG. 5 of the second embodiment.
[Explanation of symbols]
94 ... decompression chamber 93 as a pressure chamber 93 ... diaphragm 90 ... support case 115 ... spring chamber 116 ... coil spring 91a ... cylindrical part 130 ... spring receiving washer 127 ... Adjusting bolt 134: diamond-like carbon layer 135: silicon film

Claims (2)

A peripheral portion of a diaphragm (93) for applying a fluid pressure of the pressure chamber (94) to one surface is sandwiched by a support case (90), and a spring chamber (115) facing the other surface of the diaphragm (93) is provided by the support chamber (115). A coil spring (116) formed in a cylindrical portion (91a) constituting a part of the case (90) and for urging the diaphragm (93) toward the side for reducing the volume of the pressure chamber (94) is provided by the spring. A spring receiving washer (130) housed in the chamber (115) and receiving the coil spring (116) is an adjusting bolt screwed to the cylindrical portion (91a) to adjust the spring force of the coil spring (116). In the diaphragm type actuator abutting on (127), a diamond-like carbon layer (134) is formed on the surface of the spring receiving washer (130). Diaphragm actuator according to claim and. A peripheral portion of a diaphragm (93) for applying a fluid pressure of the pressure chamber (94) to one surface is sandwiched by a support case (90), and a spring chamber (115) facing the other surface of the diaphragm (93) is provided by the support chamber (115). A coil spring (116) formed in a cylindrical portion (91a) constituting a part of the case (90) and for urging the diaphragm (93) toward the side for reducing the volume of the pressure chamber (94) is provided by the spring. A spring receiving washer (130) housed in the chamber (115) and receiving the coil spring (116) is an adjusting bolt screwed to the cylindrical portion (91a) to adjust the spring force of the coil spring (116). (127) In the diaphragm type actuator contacted with (127), a silicon film (135) or a chromium film and a silicon film (13) are formed on the surface of the spring receiving washer (130). ) Or diaphragm actuator, characterized in that the diamond-like carbon layer covering the chromium film (134) are formed.

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