JPS6233178Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a valve operating device in which a control valve is controlled by an electric motor, and in particular, the lead screw can be easily positioned during assembly and can be reliably pivoted. It is.

Generally, a control valve driven and controlled by an electric motor is equipped with a valve operating device that converts the rotational movement of the output shaft by the electric motor into linear movement, and moves the valve shaft of the valve body linearly in the axial direction. . in this case,
Conventionally, a crank mechanism or a linear motion conversion mechanism using a rack and pinion has been widely used as a linear motion conversion mechanism. However, the former has the disadvantage that the input/output positioning characteristics become non-linear due to its mechanism, and the latter requires a large torque on the input side in order to obtain the strong thrust at the closed position of the valve, which is strongly required for valve operation. However, in addition to requiring a large electric motor, it was difficult to ensure the durability of the rack and pinion tooth surfaces.

Therefore, a linear motion mechanism using a lead screw and lead nut could be considered as a means to solve these problems, but when applied to this type of valve operating device, a bearing structure that can withstand a strong thrust is required, and Other problems to be solved arise, such as small dimensions and weight, low friction torque, easy installation and disassembly work, and high positioning accuracy.

Therefore, the present invention improves the above-mentioned drawbacks, and provides a lead screw in an electric valve operating device that is easy to assemble and disassemble, can support the lead screw with high precision, and can withstand large thrust with low friction torque. It is intended to provide a bearing structure.

In order to achieve the above object, the basic configuration of the present invention includes an electric motor, a worm driven by the electric motor, a worm wheel that constantly meshes with the worm, the worm wheel is fixed to one end, and the other end is fixed to the worm wheel. a lead screw having a thread formed therein; a movable body that is connected and fixed to a valve shaft of a valve body and simultaneously screwed into a male threaded portion of the lead screw and is moved in the axial direction as the screw rotates;
The movable body is provided with a cylindrical body into which the movable body is slidably fitted, and a bearing that rotatably supports the lead screw. a pair of radial bearings each fitted in a through hole of each bearing mounting body to pivotally support the lead screw; and a pair of radial bearings each disposed within the bearing mounting body to support the lead screw. It is composed of a pair of thrust bearings that are pivotally supported, and these pair of thrust bearings hold a flange that is integrally provided on the outer periphery of the lead screw, and the bearing mounting body is pressed and fixed to the cylindrical body by a presser flange. This is how it was done.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Fig. 1 is a longitudinal cross-sectional view showing an embodiment of an electric valve operating device employing a bearing structure according to the present invention, Fig. 2 is a plan view of the same device with the cover removed, and Fig. 3 is a line taken from Fig. 1. Enlarged sectional view, Figure 4 is Figure 2-
FIG.

In these figures, the electric valve operating device, which is designated as a whole by reference numeral 1, includes an electric motor 2, a reduction gear mechanism 3, a linear motion mechanism 6 including a lead screw 4 and a movable body 5,
Consists of main parts such as bearings 7 and 8 and mechanical parts,
It is disposed above the control valve 9 via a yoke 10. Note that the control valve 9 has an upper lid 1 that constitutes the valve body.
When the valve shaft 12 with one end protruding above the valve shaft 1 is moved up and down by the electric valve operating device 1, a valve plug (not shown) provided at the inner end of the valve shaft 12 is operated. Seat ring (not shown)
Since this constitutes a conventionally well-known two-way valve or three-way valve for controlling the opening and closing of the hole, detailed configuration and explanation thereof will be omitted.

In this embodiment, the electric motor 2 is an AC motor or a DC motor having a rotating output shaft, and is fixed to the frame 13 with a mounting screw 14. The frame 13 is formed into a substantially U-shape, so that a pair of mounting portions 13A, 13 facing each other are provided.
B, and a base 13C that connects these pair of mounting parts 13A and 13B, one of the mounting parts 13A
The electric motor 2 is disposed on the outer surface of the other mounting portion 13B, and the bearing 7 is disposed coaxially with the electric motor 2 on the outer surface of the other mounting portion 13B.
The tip of 5 is rotatably supported.

As shown in Fig. 3, the bearing 7 has a hollow cylindrical bearing mounting body 17 which is fitted and fixed from the outside into a through hole 16 provided in the mounting portion 13B, and the tip of the output shaft 15 is inserted into this bearing mounting body 17 via a radial bearing 19, and is rotatably supported by a thrust bearing 18 and prevented from moving in the axial direction by a screw 26 which will be described later.
A retaining ring 20 is fitted to the shaft 15 for receiving thrust in the rightward direction in the drawing, and a semicircular recess is formed on the tip surface of the shaft 15, into which a ball 21 is fitted and fixed by caulking. A male thread 22 is formed on the outer peripheral surface of the bearing attachment body 17 protruding from the through hole 16, and a cap 22 is fitted to the male thread 22 with a female thread formed on the inner peripheral surface.
The cap 23 is secured to the nut 25 by a set screw 24.
The screw 26 is screwed in through the
The ball 21 is supported by the tip end surface of the bearing mounting body 17, which allows fine adjustment of the output shaft 15 in the axial direction and supports the leftward thrust.
Further, a highly viscous lubricant 27 such as grease is sealed inside the thrust bearing 18, the radial bearing 19 and the balls 21.
The output shaft 15 is fixed to the one mounting portion 1 of the frame 13.
3A, and determines the position of the output shaft 15.

The reduction gear mechanism 3 includes a worm 30 provided at the intermediate portion of the output shaft 15 and located between the pair of attachment portions 13A and 13B, and a worm wheel 31 that meshes with the worm 30 at all times. In this case, for convenience of explanation, FIGS. 1 and 2 show an example in which the worm 30 is formed integrally with the output shaft 15, but in an actual device, the worm 30 and the output shaft 15 are formed integrally as shown in FIG. It is common sense and desirable to form them as separate members and to connect them using an appropriate shaft coupling 29. The worm wheel 31 is fitted onto the upper end of the lead screw 4, which is disposed in a direction perpendicular to the output shaft 15 (vertical direction) with a predetermined distance between the shafts, and is secured by a nut 32. Fixed. The lead screw 4 is disposed above and coaxially with the valve shaft 12, and is supported by a bearing 8 so as to be rotatable and prevented from moving in the axial direction.

As shown in FIG. 1, the bearing 8 has a pair of upper and lower bearing fittings 33, 34 through which the lead screw 4 commonly passes.
A pair of thrust bearings 35 and 36 are housed inside to pivotally support the lead screw 4. In this case, the pair of thrust bearings 35 and 36 are disposed above and below a collar 37 that is integrally provided on the outer periphery of the lead screw 4. The pair of bearing mounting bodies 33, 34
can be separated by screwing the male threaded portion 33a provided on the outer circumferential surface of the lower end of the upper bearing mounting body 33 into the female threaded portion 34a provided on the inner circumferential surface of the upper end of the lower bearing mounting body 34. They are combined and fixed in a predetermined position with respect to the frame 13 and the cylinder 40 that constitute the device fixing part by means of a presser flange 28, which will be described later. And the bearing mounting body 33,
Through holes 41 formed on the upper and lower surfaces of 34,
Radial bearings 43 and 44, which rotatably support the lead screw 4, are press-fitted and fixed to 42, respectively.

The base 13C of the frame 13 is connected to the cylindrical body 40.
It is firmly fixed to the upper end surface of the bearing body by a plurality of mounting screws 45, and a fitting hole 46 into which the lower bearing mounting body 34 is fitted is provided in the center. Further, the lower bearing mounting body 34 is also fitted into the inner hole 47 of the cylinder body 40, and the lower surface of the fitting body is abutted and latched to a stepped portion 48 provided on the upper end opening side of the inner hole 47. This prevents it from being inserted into the cylindrical body 40 any further. On the other hand, the presser flange 38 is fitted onto the outer periphery of the upper bearing mounting body 33. This presser flange 38 has a plurality of screw mounting holes formed near the outer periphery, each of which has a mounting screw 50 inserted therein.
is inserted into the upper end surface of the cylindrical body 40 through the attachment hole 51 provided in the base 13C of the frame 13.
is pressed downward, thereby pressing the lower bearing mounting body 34 against the stepped portion 48. Therefore, the pair of bearing mounting bodies 33 and 34 are coaxially and firmly fixed to the cylinder body 40 in a screwed-together state. When the upper bearing mounting body 33 is screwed into the lower bearing mounting body 34, the pair of thrust bearings 35 and 36 come into contact with the collar 37, so it is possible to eliminate play in the axial direction of the lead screw 4. . In addition, the frame 13 has a mounting portion 13A.
has the bearing hole 28 for positioning the electric motor 2 at a predetermined location, and by positioning and fixing itself on the cylindrical body 40, the worm 30 and the worm wheel 31, in other words, the output shaft 15 and the axis of the lead screw 4. The distance can be set with high precision.

The cylindrical body 40 has a lower end fitted into a fitting hole 54 provided at the center of the frame 53, and a nut 56 is screwed onto the downwardly protruding end of the frame 53, so that the cylindrical body 40 can be attached to the frame 53. 53 and is fixed upright. In this case, the cylinder 40 is connected to the pin 55
is positioned and prevented from rotating. A movable body 5 is disposed in the lower part of the interior of the cylinder 40 and is moved in the vertical direction as the lead screw 4 rotates.
is slidably inserted.

The movable body 5 has an outer cylinder 57 and an inner cylinder 58 disposed coaxially within the outer cylinder 57, and the outer cylinder 57 is slidably inserted into the inner hole 47 of the cylinder body 40. . The inner cylinder 58 is a guide block 6 which will be described later.
0 constitutes an oil tank 61, and this inner cylinder 5
The lower end of a lead nut support 63 is slidably inserted into the upper end opening of the lead nut support 63 via an O-ring 62. The lead nut support 63 is formed in a hollow shape, and its upper end is connected to the inner hole 64 of the outer cylinder 57.
It is fixed by welding, etc. Further, a lead nut 65 made of a material with excellent wear resistance and low friction is press-fitted into the inside of the lead nut support 63 and fixed by caulking. This caulking fixation is performed by bending the upper end opening of the lead nut support 63 toward the center and pressing it against the upper surface of the lead nut 65. The lead screw 4 is inserted into the screw hole 65A of the lead nut 65.
A male threaded portion 66 provided on the outer peripheral surface of the lower end portion is screwed.

The guide block 60 that constitutes the oil tank 61 together with the inner cylinder 58 is fitted into the lower end opening of the inner cylinder 58 and fixed by welding.
The lower end opening of 8 is sealed. And inner cylinder 5
8 contains lubricant 67 such as lubricating oil and grease.
This prevents the external threaded portion 66 of the lead screw 4 and the lead nut 65 from being worn out due to lack of oil film or lack of oil, thereby ensuring smooth rotation of the lead screw 4.

By the way, as mentioned above, when an AC motor or a general DC motor is used as the motor 2, if the motor 2 is forced to stop while the current is on, problems such as overheating often occur in the motor 2, and the output torque characteristics of the motor 2 is not constant based on the input signal alone, and has load followability, so excessive stress is applied to various parts of the electric valve operating device 1 and the control valve 9 side, often causing problems. Therefore, in order to prevent such problems, a buffer spring 68 constituting a buffer mechanism is interposed between the outer cylinder 57 and the inner cylinder 58, and when the control valve 9 is fully closed, the buffer spring 68 is compressed more than the built-in compression amount. Further, the electric motor 2 is stopped after being compressed by a predetermined amount. Therefore, the buffer spring 68 has a pair of spring receivers 69 that are fitted to the outer peripheries of the inner cylinder 58 and the guide block 60 so as to be able to move up and down.
The bullet is loaded between A and 69B, and the upper spring receiver 69A
A retaining ring 70 fitted to the outer peripheral surface of the upper end of the inner cylinder 58 prevents the inner cylinder 58 from coming off. On the other hand, the guide block 6 allows the lower spring receiver 69B to come out downward.
This is prevented by the large diameter portion 60A provided at the lower end of the 0. The stopper 71 is fitted onto the outer peripheral surface of the guide block 60 so as to be prevented from rotating, and its outer peripheral edge is fitted into the lower end opening of the outer cylinder 57 and fixed by caulking or the like. As shown in FIG. A pair of engagement grooves 74 provided on the surface
(See Figure 1). Further, the stopper 71 is fixed by caulking by bending the lower end opening of the outer cylinder 57 toward the center and pressing the stopper 71 from below.
3, a stepped portion 7 provided on the inner circumferential surface of the lower end opening.
Just press it to 5. At this time, a portion of the lower end opening of the outer cylinder 57 bites into the notch 73, thereby firmly preventing the stopper 71 from rotating.

Incidentally, the incorporation of the buffer spring 68
8 is elastically mounted between a pair of spring receivers 69A and 69B with a retaining ring 70, and a guide block 6.
0 is inserted from the lower end opening of the outer cylinder 57, and the stopper 71 is fitted into the lower end opening of the outer cylinder 57 and fixed by caulking. Mounted internally. Note that a stepped portion 88 for locking the spring receiver 69A is provided on the inner circumferential surface of the outer cylinder 57.

A screw hole 76 is formed in the center of the lower surface of the guide block 60, and a connecting bolt 77 is screwed into the screw hole 76 via a nut 78. A bolt 80 is disposed through the head 77a of the connecting bolt 77 in the diametrical direction of the bolt 77, and is fixed by a pair of nuts 81 and 82. The tip of the bolt 80 is sharply formed to form a pointer, and a pair of left and right connecting fittings 83, 84 are fixed to the bolt 77 together with the pair of nuts 81, 82. The connecting fittings 83 and 84 have insertion holes (not shown) provided at their straight upper ends that are in close contact with both sides of the head of the connecting bolt 77, respectively, and the bolt 80 is inserted into these insertion holes. There is. On the other hand, the lower end portions of the connecting fittings 83 and 84 are bent into a substantially hook shape, with their tips facing each other, and the upper end portion of the valve stem button 85 is held between these lower end portions. The valve stem button 85 is connected to the valve stem 12.
It is screwed and fixed to the upper end of the connecting bolt 77, and its upper surface is in contact with the lower surface of the head 77A of the connecting bolt 77. In addition,
The upper end of a locking metal fitting 86 formed in a substantially L-shape is fixed to the bolt 80 by a nut 87, and the lower end of this locking metal fitting 86 is formed in a U-shape when viewed from above in FIG. By engaging with the outer periphery of the hexagonal portion of the valve stem button 85, rotation of the valve stem 12 is prevented.

The rotation of the movable body 5 itself is prevented by a pair of left and right rollers 90 and 92, as shown in FIG. These pair of rollers 90 and 91 are rotatably supported via spacers 94 at intermediate portions of roller support pins 92 and 93, respectively, which are attached to the outer peripheral surface of the upper end of the outer cylinder 57 from inside the outer cylinder 57. has been done. the pair of roller support pins 92;
Nuts 93 are respectively projected to the outside from elongated holes 95 and 96 formed in the axial direction on the circumferential surface of the cylindrical body 40, and nuts 98 are respectively screwed to the projecting ends via washers 97. The pair of rollers 90 and 91 are located within the respective elongated holes 95 and 96 to prevent the movable body 5 from rotating. Therefore, when the lead screw 4 rotates, the movable body 5 moves only in the vertical direction, and at this time, the pair of rollers 90, 91 contact the wall surfaces of the elongated holes 95, 96 and rotate, so that the cylindrical body Reduces frictional resistance of 40.

An electric motor 2 is mounted on the base 13C of the frame 13 in correspondence with the pair of roller support pins 92 and 93.
A switch mechanism 100 and a position detection mechanism 101 are provided.

As shown in FIGS. 2 and 4, the switch mechanism 100 includes a slide cam 103 that is slidably held by a pair of vertically arranged rails 102a and 102b, and this slide cam 10.
A pair of micro switches 1 arranged on both sides of 3
04,105.

The slide cam 103 is fixed to the upper end of a threaded rod 106, and the lower end of the threaded rod 106 is connected to a hole 107 provided in the base 13C of the frame 13.
It is threadedly connected to a connecting rod 108 that extends below the frame 13 and is rotatably supported by the tip of the roller support pin 92 . Therefore, when the movable body 5 moves up and down, the threaded rod 10
6 moves up and down together with the roller support pin 92, the slide cam 103 moves up and down along the pair of rails 102.
a, 102b. Further, on both sides of the slide cam 103, projections 110 and 11 have inclined cam surfaces 112 and 113, respectively.
1 is integrally provided. the cam surface 112,
113 are formed so that their inclination directions are opposite to each other as shown in FIG. 4, and these cam surfaces 1
12, 113, the pair of micro switches 10
Rollers 117 attached to each of the elastic pieces 116 of 4 and 105 are pressed against each other.

In this case, when the slide cam 103 rises with the rise of the movable body 5, the cam surface 112 gradually presses the roller 117 of the micro switch 104, elastically deforming the elastic piece 116, and the slide cam 103
When the motor reaches the highest position, the switch 104 is closed and the electric motor 2 is stopped by the signal at this time. On the other hand, as the movable body 5 descends, the slide cam 1
03 is lowered, the cam surface 113 gradually presses the roller 117 of the micro switch 105 and elastically deforms the elastic piece 116 of the switch 105, so when the slide cam 103 reaches the lowest position,
The micro switch 105 is closed, thereby stopping the electric motor 2.

The position detection mechanism 101 is for detecting the opening degree of the regulating valve 9 as the movable body 5 moves up and down, and sending the detection signal to an appropriate display or control means.
Similar to the switch mechanism 100, a pair of rails 1
It has a slider 121 that is slidably held in the vertical direction by 20a and 120b, and a wiper 122 of a potentiometer shown in FIG. 2 is disposed on one side of the slider 121, and a resistor 123
is in elastic contact with. The slider 121
is fixed to the upper end of a threaded rod 124, and the lower end of this threaded rod 124 is threadedly connected to a connecting rod 125 that extends below the frame 13 and is rotatably supported by the roller support pin 93. There is. Therefore, when the movable body 5 moves up and down, the threaded rod 124 moves up and down together, so the slider 121 moves up and down along the pair of rails 120a and 120b. As a result, the wiper 122 and the slider 12
1 and changes the contact position with the resistor 123, thereby changing the resistance value of the position detection mechanism 101.

The switch mechanism 100 and the position detection mechanism 101 are respectively housed in cases 127 and 128 fixed to the upper surface of the base 13C of the frame 13.

As shown in FIG. 1, the frame 53 on which the cylindrical body 40 is erected and fixed is placed on the upper surface of the yoke 10 and is firmly fixed by a plurality of bolts 130. A lower end opening of a cover 131 that covers the electric valve operating device 1 is fixed by a set screw 132 . The yoke 10
is formed into a substantially U-shape, and its lower end is fitted into the upper part of the upper lid 11 and fixed by two setscrews 133. Further, on the inner surface of the yoke 10, a scale plate 134 is provided on the set screw 1 in correspondence with the bolt 80.
35 and a long hole 136 so that the height can be adjusted. On the surface of this scale plate 134 are numbers "0" and "100" indicating when the control valve 9 is fully closed and fully open.
is displayed.

Next, the operation of the electric valve operating device 1 having such a configuration will be explained. Note that the explanation assumes that a three-way valve is operated.

When the electric motor 2 stops and the lower seat ring of the control valve 9 is fully closed, the movable body 5 stops at the lowest position, and the pointer, that is, the tip of the bolt 80 points to the number "0" on the scale plate 134. are doing. At this time, a slight gap _G1 is created between the lower spring receiver 69B and the stopper ₇₁ , as shown in FIG. , a spring load is applied downward to the valve stem 12. In this case, the upper spring receiver 69A
is press-fitted to a stepped portion 88 provided inside the outer cylinder 57 by the force of the buffer spring 68, and creates a gap G ₂ between it and the retaining ring 70 that is equal to the gap G ₁ .

In this state, the electric motor 2 is energized,
When the output shaft 15 is rotated in the forward direction, this rotation is reduced by a predetermined reduction ratio by the worm 30 and the worm wheel 31, and is transmitted to the lead screw 4. When the lead screw 4 rotates, the movable body 5 equipped with the lead nut 65 screwed thereon gradually rises because it is prevented from rotating by a pair of rollers 90 and 91, and the valve connected to the connecting bolt 77 moves upward. Pull up the shaft 12. That is, the rotational motion of the output shaft 15 is decelerated by the reduction gear mechanism 3, and converted into linear motion by the linear motion mechanism 6 made up of the lead screw 4 and the movable body 5.
is transmitted to move the valve shaft 12. The relationship between the amount of rotation and the amount of movement of the valve stem 12 at this time shows extremely good linear characteristics.

When the movable body 5 rises, the male threaded portion 66 of the lead screw 4 relatively descends, so it enters the oil tank 61 as shown in FIG. It will be done. When the movable body 5 further rises and reaches the uppermost position, the upper seat ring of the control valve 9 is fully closed and the pointer 80 moves toward the scale plate 1.
34 number "100" and switch mechanism 10
0 microswitch 104 (see FIG. 4) is closed by cam surface 113, stopping electric motor 2. In this case, even after the upper seat ring of the control valve 9 is fully closed, the movable body 5 stops at a position raised by a predetermined amount. Push up the lower spring receiver 69B as shown. On the other hand, since the retaining ring 70 is fitted onto the outer periphery of the cylinder 58 which is movable relative to the outer cylinder 57, the outer cylinder 57 moves upward and a slight gap is created between the stepped portion 88 and the spring receiver 69A. will occur. As in the case when the lower seat ring is fully closed, the buffer spring 68 is compressed by a predetermined amount more than the compression amount at the time of installation. Therefore, even when the upper seat ring is fully closed, the spring load can be applied upwardly to the valve stem 12 by the buffer spring 68.

According to the electric valve operating device 1 having such a configuration, the lead screw 4 is pivotally supported by the pair of thrust bearings 35 and 36 and the radial bearings 43 and 44, respectively, so that the axial and diametrical There is no play, and the shaft can be reliably supported with low friction torque. Furthermore, a pair of bearing fittings 33 and 34 that accommodate these bearings 35, 36, 43, and 44 are fitted into the fitting holes 46 of the frame 13.
The valve stem 12
There is no axial deviation even when driving with large thrust. Further, since the bearing 8 has a simple structure and can be formed into a unit together with the lead screw 4, it is easy to attach and remove, and the distance between the output shaft 15 and the lead screw 4 can be set with high precision during assembly. Furthermore, since there is little loss due to frictional torque, it is possible to use a small electric motor, thereby reducing costs.
In addition, since the radial bearings 43 and 44 are press-fitted and fixed into the through holes 41 and 42 of the respective bearing fittings 33 and 34, foreign matter such as dust is prevented from entering into the bearing fittings 33 and 34, and Since the thrust bearings 35 and 36 have a structure that prevents them from coming into contact with the outside air, the rust prevention effect is great and the durability of the bearing 8 is improved.

Figure 8 shows stepper motor (stepping motor) 1
FIG. 5 is a cross-sectional view of a main part showing another embodiment of the present invention using a 50. In this case, the floor motor 150 will self-stop when it receives an overload that exceeds the load corresponding to the output torque corresponding to the input signal, and there will be no problem even if the continuous energization continues, and the motor 150 will If the output torque has a characteristic that is uniquely determined with respect to the input signal, there is an advantage that the buffer spring 68 shown in FIG. 1 can be made unnecessary. Therefore, the structure of the movable body 5 can be simplified, the assembly work is easy, and the guide block 60 can be directly fitted into the lower end opening of the outer cylinder 57 and fixed by welding or the like. Also,
In this embodiment, the inner cylinder 58 is not necessarily required as the oil tank 61, and the outer cylinder 57 may be used as the oil tank. It should be noted that the other configurations are configured similarly to those of the above embodiment, and therefore are indicated by the same reference numerals and the explanation thereof will be omitted.

As explained above, the electric valve operating device according to the present invention has a bearing structure for a lead screw constituting a linear motion mechanism, a pair of bearing mounts that are separably coupled, and a pair of bearing mounts housed within the pair of bearing mounts. The pair of bearing mounting bodies are each configured with a pair of thrust bearings and a radial bearing, and the pair of bearing mounting bodies are fitted into an inner hole (fitting hole) of a cylinder body that slidably accommodates a movable body that is moved by the frame and the lead screw. Since they are fitted and fixed under pressure by the presser flange, the lead screw can be pivotally supported with low friction torque and without play. Also,
The structure is simple and assembly work is easy, and the lead screw and bearing structure can be integrated into a unit, so by fitting and fixing the pair of bearing mounting bodies into the fitting holes, the installation position of the lead screw can be uniquely determined. determined, and high installation accuracy can be obtained. Furthermore, the bearing structure is easy to disassemble, has excellent handling properties and durability, and has great practical effects.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of an electric valve operating device employing a reed screw bearing structure according to the present invention, Fig. 2 is a plan view of the same device with the cover removed, and Fig. 3 is the same as Fig. 1. - line enlarged sectional view, 4th
The figures are a cross-sectional view taken along the lines shown in FIG. 2, FIG. 5 is a plan view of the stopper, FIGS. 6 and 7 are diagrams for explaining compression of the buffer spring, and FIG. 8 is a diagram showing another embodiment of the present invention. FIG. 1... Electric valve operating device, 2... Electric motor, 3...
Reduction gear mechanism, 4... Lead screw, 5... Movable body, 6... Linear motion mechanism, 7, 8... Bearing, 9
... Control valve, 12 ... Valve stem, 13 ... Frame,
15... Output shaft, 30... Worm, 31... Worm wheel, 33, 34... Bearing mounting body, 3
5, 36... Thrust bearing, 38... Holder flange, 40... Cylindrical body, 43, 44... Radial bearing, 46... Fitting hole, 50... Mounting screw, 66...
...Male thread part.

Claims (1)

[Scope of utility model registration request] An electric motor, a worm driven by the electric motor, a worm wheel that constantly meshes with the worm, a lead screw to which the worm wheel is fixed at one end and a thread formed at the other end, and a valve shaft of a valve body. a movable body that is connected and fixed to the lead screw, is simultaneously screwed to the male threaded portion of the lead screw, and is moved in the axial direction as the screw rotates;
The movable body is provided with a cylindrical body into which the movable body is slidably fitted, and a bearing that rotatably supports the lead screw. a pair of radial bearings each fitted in a through hole of each bearing mounting body to pivotally support the lead screw; and a pair of radial bearings each disposed within the bearing mounting body to support the lead screw. The lead screw is configured with a pair of thrust bearings that are pivotally supported, and these pair of thrust bearings hold a collar that is integrally provided on the outer periphery of the lead screw, and the bearing mounting body is pressed and fixed to the cylindrical body by a presser flange. A bearing structure for a lead screw in an electric valve operating device characterized by: