JP4154115B2 - Stepping motor assembly for valve control - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a stepping motor assembly for valve control used for, for example, flow rate control of refrigerant in an air conditioner and flow rate control of combustion gas, air, hot water, liquid fuel, etc. in a bath or shower.
[0002]
[Prior art]
A stepping motor as a means that can precisely control the amount of rotation electronically is useful as a drive system for a flow control valve in applications that require precise flow control of fluids such as refrigerants and fuels. It's being used.
[0003]
And the proposal about the usage method of the stepping motor in such a use is made into the assembly which has the structure suitable for a use unlike the stepping motor considered alone. For example, in air conditioners that are widely used not only in commercial applications but also in general households, the mechanism for controlling the amount of refrigerant circulation, which is important for controlling the cooling temperature, is uniquely refined. Of course, it is necessary to meet these requirements, but in addition to this, low cost and excellent durability are required because it is a device that can be used for a long time, and these requirements are satisfied. For this purpose, various improvements are required, including not only the configuration of the stepping motor alone but also the operation of the valve mechanism on the controlled side.
[0004]
Here, the history of the development of the stepping motor assembly for valve control over the past ten years is as follows.
[0005]
There is a structure in which the rotor part of the stepping motor and the controlled valve are accommodated in one sealed housing, the stator part is fixedly arranged on the outer periphery of the rotor part, and the rotor shaft is used as the output shaft for valve control as it is. It was known. However, this configuration has a fatal problem that the torque between the rotor and the stator is large because the gap between the rotor and the stator is large, and a large thrust is required to obtain a large thrust, and the resolution of the motor is low. There was a problem.
[0006]
To solve the above problem, for example, the output shaft of the speed reduction mechanism is driven from the rotor shaft of the stepping motor via the speed reduction mechanism, and the final output shaft of the stepping motor assembly is driven by the rotation of the output shaft. Accordingly, a stepping motor assembly has been proposed in which a large thrust is obtained with a small motor and a high resolution is obtained (see FIG. 4 of Japanese Patent No. 2887395).
[0007]
However, in this proposal, a negative force is applied to the end of the output shaft of the speed reduction mechanism in order to transmit the rotational force between the output shaft of the speed reduction mechanism and the screw shaft that is the final output shaft that can be moved back and forth in the axial direction. The driver shape needs to be machined, and the other final output shaft end side needs to be grooved so that it can slide relative to the negative screw shape to allow relative movement in the axial direction. It was pointed out that the cost was high and the production cost was high due to the large number of parts. There is also proposed a type in which the output shaft of the speed reduction mechanism is used as the final output shaft of the stepping motor assembly, that is, a structure that moves forward and backward while rotating the output shaft (Japanese Patent No. 2608579). .
[0008]
However, the improved stepping motor assembly has a problem that the production cost is high due to the large number of parts and the assembly man-hours. In addition, the structure using the former transmission mechanism is in addition to that. In the latter structure, the O-ring is used to hermetically seal the internal space of the housing that houses the gear train of the stepping motor and the speed reduction mechanism from the outside. There is a problem that a large number of parts are required. Specifically, this problem is explained as follows. That is, ensuring airtight sealability not only depends on the material of each sealing member such as an O-ring, but also makes assembly mistakes in the assembly process fatal. It is. Accordingly, reducing the number of assembly steps can provide not only the advantage of reducing the production cost by reducing the number of steps but also the advantage of effectively contributing to the improvement of the reliability of the product in mass-produced products. However, the structure proposed in the above-mentioned Japanese Patent No. 2608579 is not preferable in this respect because there is an operation process for incorporating an O-ring, and thus improvement is required. Also, in an environment where water droplets freeze, the stepping motor assembly results in the sealing being invalidated due to the occurrence of cracks in the sealing portion of an adhesive or the like that has been subjected to a process for hermetically sealing the inside and outside of the housing. There was also a possibility of impairing the durability.
[0009]
Separately from the above proposal, a stud bolt that does not rotate or reciprocate is provided in the housing to form a male screw portion, and a female screw member that moves forward and backward while rotating is screwed onto the male screw portion of the stud bolt. A stepping motor assembly having a combined structure has been proposed (Japanese Patent Publication No. 6-15909).
[0010]
However, in the proposed stepping motor assembly, since the female screw member as the final output shaft having the female screw portion screwed with the male screw portion of the stud bolt is linked to the gear of the speed reduction mechanism, these are rotated. However, since it is necessary to screw in, it causes inconvenience in assembling work, and since a member for guiding the forward and backward movement of the female screw member is also necessary, it is not necessarily advantageous in terms of miniaturization and weight reduction. Furthermore, since a die-cast molded product is used for hermetically sealing the inside of the housing from the outside, there is also a problem that the cost of the stepping motor assembly is increased. Further, since the connection of the power supply line is provided on the upper side of the housing, there is a problem that water droplets accumulated on the seal portion freezes and the sealing performance of the seal portion is impaired.
[0011]
A stepping motor assembly in which the above problems are further improved is proposed by Japanese Patent No. 2887395. As shown in FIGS. 3 and 4, the housing 20 of the stepping motor assembly is composed of a bottomed cylindrical main body 21 and a cap 22 that covers the ceiling opening 211. The female screw member 23 is fixed to the lower opening 212 of the housing 21, and a final output shaft 24 (a male screw member that moves forward and backward while rotating) extends downward from the bottom of the housing main body 21. In addition, a member such as a gear train of the speed reduction mechanism is sequentially assembled from the lower side at an upper portion thereof, and a power supply line (lead wire) 35 is provided from an introduction port provided on the lower surface side of the housing body 21. It is designed to be introduced into the housing 20. The members such as the gear train include an output gear 25, an intermediate gear 26, a shaft column 27, an intermediate gear 28, and a motor pinion 29, which are an intermediate base plate 31, an upper base plate 32, and a reaction plate fixed to the upper base plate 32. It is supported by the output bearing 30.
[0012]
Then, the stepping motor 36 is fixed on the upper base plate 32 to cover the cap member 22, and the periphery of the cap member 22 is clamped by holding the sealing agent 38 to seal the inside of the housing from the outside air. A power supply line 33 made of a flexible printed board connected to 36 is led out of the housing through the protective bush 34 and electrically connected to the lead wire 35. The connection portion is filled with a sealant 37 and moisture enters from this portion. To prevent. Reference numeral 40 denotes a lock nut which is assembled to the lower portion of the housing main body 21 so as not to be removed by the stopper ring 41 and is screwed and fixed to the body of the external controlled valve. A steel ball 42 is fixed to the tip of the final output shaft 24, and moves the valve body of the controlled valve forward and backward by the forward and backward movement of the final output shaft. Reference numeral 43 denotes a stopper ring for determining the top dead center of the final output shaft 24.
[0013]
In the proposed stepping motor assembly, the inside of the housing is formed by caulking the cap member 22 that is crowned so as to close the ceiling opening 211 of the housing body 21 that has been die-cast molded with a sealant. It has the feature that it can be hermetically sealed effectively from the outside, and is excellent in terms of miniaturization and weight reduction.
[0014]
[Problems to be solved by the invention]
However, it goes without saying that even if the stepping motor assembly proposed by the above-mentioned Japanese Patent No. 2887395 is excellent, it is common knowledge in the art that even better improvements are required.
[0015]
The present inventors have studied from various points in order to further improve the technology from such a viewpoint, and have come to make the present invention.
[0016]
The first of the above considerations is to reduce the number of parts that make up the stepping motor assembly, thereby reducing the number of man-hours for assembling the assembly and lowering the cost. One of the objects is to provide a stepping motor assembly having a structure devised so as to reduce as much as possible.
[0017]
Secondly, by further improving the hermetic sealing of the outside of the stepping motor assembly inside the housing, the same standard can be used even in environments where the temperature changes greatly, such as from cold regions to tropical and subtropical regions. The point that satisfies the requirement to be able to respond with the product is mentioned. That is, according to the proposal of the above-mentioned Japanese Patent No. 2887395, the feeding wire (lead wire) is introduced into the inside from the lower side of the housing of the assembly, and the introduction opening is sealed with a sealing agent. Cracks of the seal portion due to freezing of the water droplets and the like are effectively prevented, and hermetic sealing is effectively realized. However, even with such a stepping motor assembly, there are rare cases where malfunctions occur during long-term use. It was revealed that this was caused by moisture intrusion into the housing. Accordingly, another object of the present invention is to eliminate such a problem.
[0018]
In order to investigate the cause of the above problem in detail, the route of moisture intrusion was examined. It was confirmed that moisture penetrated into the core wire passing through the inside of the feeder wire (lead wire) due to capillary action or negative pressure from inside the housing due to increase / decrease of ambient temperature. The present invention also provides a structure capable of effectively preventing the problem of moisture intrusion from the core wire portion.
[0019]
Thirdly, when the final output shaft of the stepping motor assembly is a male screw member that advances and retracts while rotating through the female screw member fixed to the housing, the advancement and retraction of the male screw member is poor. In some cases, the following were clarified when the cause was examined in detail. That is, in general, in order to stabilize the movement of the member that moves forward and backward by the rotation of the screwing portion (the above-mentioned final output shaft corresponds to this), in order to accurately give the direction of the forward and backward movement, In general, a straight cylinder sliding portion that slides on the final output shaft that moves forward and backward is provided. However, in applications that require precise control of the valve opening / closing degree on the controlled side by the forward / backward movement of the output shaft, in order to accurately determine the home position (origin: the point that determines the degree of valve opening) It has been found that an operation of so-called tightening is performed, which causes the above-described poor advancement and retraction of the male screw member. That is, the above-described “tightening” operation is an operation of pushing the valve body strongly against the valve seat to precisely control the opening / closing degree of the controlled side valve, thereby returning the origin, and by this operation, the stepping motor assembly The final output shaft receives a strong reaction force in the axial direction during the same operation. Therefore, considering various forces acting on the final output shaft of the stepping motor assembly in such “tightening” operation, the axial direction of the straight cylinder sliding portion with the fixed portion and the male of the final output shaft moving forward and backward Even if the direction of the threaded shaft center of the screw portion and the female screw portion is deviated even within the tolerance range, it is subjected to a twisting action, and a so-called twisting or biting phenomenon occurs. The advance / retreat failure of the screw member occurs.
[0020]
Another object of the present invention is to eliminate such problems.
[0021]
[Means and Actions for Solving the Problems]
The features of the valve control stepping motor assemblies (1) and (2) of the present invention proposed to achieve the various objects described above are as follows.
(1) A stepping motor, a speed reduction mechanism, a male screw portion provided on the output shaft of the speed reduction mechanism, a female screw member having a female screw portion screwed with the male screw portion, and a ground plate for fixing the female screw member The outer case is fixed, Stepping motor And said Deceleration mechanism Contain A stepping motor assembly comprising a housing and a coupling means provided on the female screw member for mechanical connection to a controlled valve mechanism, wherein the base plate has a substantially flat plate shape. Only To hermetically seal the inside of the housing from the outside , Main plate and One side Fucked in Layer integration With an elastic body It is characterized by comprising.
(2) a stepping motor, a speed reduction mechanism, a male screw portion provided on the output shaft of the speed reduction mechanism, a female screw member having a female screw portion that is rotatably engaged with the male screw portion, and a substantially flat plate-like member A base plate and a housing forming an internal space partitioned from the outside by an outer case covered on the base plate, and the stepping motor and the speed reduction mechanism linked to the output shaft are housed in the housing. The female screw member is fixed to the ground plate of the housing, and the output shaft is provided so as to extend vertically downward through the female screw member. The ground plate has a substantially flat plate shape. Main plate body And the Main plate body A sheet-like elastic body integrated on the lower surface of the outer case, and by staking the periphery of the outer case around the elastic body side of the lower surface of the base plate, Main plate body In addition, the elastic body is pressed to provide a space in the housing that is hermetically sealed from the outside.
[0022]
In the above inventions (1) and (2), it is preferable that a synthetic resin molding member for supporting each gear of the gear train constituting the speed reduction mechanism and for positioning and fixing the stepping motor is incorporated in the housing.
[0023]
In the above configuration, it is important that the base plate has a substantially flat plate shape. That is, the fact that the housing body of the conventional stepping motor assembly described above is a die-cast molded product is a factor that increases the manufacturing cost of the parts and ultimately increases the cost of the stepping motor assembly. This is because it is possible to eliminate the need for the housing body to be a die-cast molded product by configuring the base plate with a substantially flat base plate as described above. Here, “the base plate has a substantially flat plate shape” means that the rigid portion as the main body of the housing can be formed by a press-formed product of a metal material such as a steel plate, and a die-cast molded product is required. It means not to.
[0024]
Further, in addition to the above-described invention, the feature of the stepping motor assembly for valve control of the present invention made to achieve the above various objects is as follows (3).
(3) The invention of (2) The main plate body A sheet-like elastic body made of a metal member and integrated therewith is a rubber member, and the rubber member The main plate body It is characterized by being integrated by baking or bonding.
[0025]
Configure the main plate in (3) above On the main plate body A metal plate such as a steel plate to which rust prevention treatment such as galvanization is applied is preferably used. As the elastic body, a rubber material excellent in weather resistance and durability, for example, a chloroprene rubber material is preferably used.
[0026]
Furthermore, the features of the stepping motor assembly of the present invention made to achieve the above various objects in addition to the above invention are as follows (4) to (6).
(4) The inventions of (2) and (3) Above Ground plane Of the body A space where an opening for introducing a power supply line to a stepping motor is provided in a part and the power supply line from the outside is inserted Inside , The main plate Body Into the housing from the opening The sheet-like elastic body Let it extend Make this void concave Forming a terminal electrically connected to the stepping motor at one end to be hermetically sealed in the space and projecting, and a feeder line inserted into the space from outside The terminal It is characterized by being electrically connected.
(5) Of the inventions of (2) to (4) The main plate body The space into which the power supply line is inserted from the opening for introducing the power supply line to the stepping motor provided in a part of is sealed with a sealing agent.
(6) The female screw member according to the inventions (2) to (5) is characterized in that coupling means for mechanically connecting and fixing to the controlled valve mechanism body is provided.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
The valve control stepping motor assembly of this example shown in FIGS. 1 and 2 forms a housing by the base plate 1 and an outer case 2 fixed above the base plate 1 to ensure that moisture enters the housing. The valve control stepping motor assembly (hereinafter referred to as “stepping motor assembly” or simply “assembly”) for use in controlling the flow rate of refrigerant such as an air conditioner. It is used effectively.
[0028]
In these drawings, FIG. 1 is a developed view for easy understanding of the structure of this example (particularly, the relationship of gear train linkage of the driving force transmission system). Specifically, in FIG. 2 showing a state in which the assembly is viewed in a horizontal cross section from the bottom surface side, from the axis of the fixed shaft 302 on which the rotor 301 of the stepping motor 3 is rotatably slidable, An output shaft gear that connects the shafts of the rotation shafts 401, 501, and 601 of the gears 4, 5, and 6 constituting the gear train, and is also the output shaft of the speed reduction mechanism and the final output shaft of the stepping motor assembly 7 shows a planar development of a longitudinal section of a line connecting the shaft centers of the rotation output shaft 701 of FIG. Therefore, FIG. 2 corresponds to the actual structure of the assembly, but FIG. 1 is a hypothetical diagram shown for easy understanding of the relationship of the gear train of the reduction gear mechanism as described above. It is. Each of the shafts indicated by the reference numerals 302, 401, 501, and 601 is a fixed shaft that does not rotate itself, while the output shaft 701 rotates the shaft itself. The rotor 301 includes a synthetic resin spacer 3011, a magnet 3012, and a motor pinion 3013 formed at the spacer end.
[0029]
One of the features of the stepping motor assembly of this example is that the ground plane 1 is composed of a ground plane body 101 made of metal (galvanized steel sheet) and an elastic body layer (chloroprene rubber layer) 102 laminated and integrated on the lower surface thereof. In terms of structure, it has a substantially circular flat plate shape, and a predetermined opening and a stepped portion (flange portion) having a circular periphery are formed by press molding.
[0030]
It is an important point of this example that the base plate 1 is configured by press molding, and thereby, the part cost in the case of using a conventional die cast product can be greatly reduced.
[0031]
The integration of the metal base plate body 101 and the rubber layer 102 can be performed by bonding with an adhesive, baking the rubber layer 102 onto the base plate body 101, or the like. In the case of adhesion, an intermediate rubber layer or the like for improving the adhesion to the ground plate body 101 can be provided for the base treatment or adhesion.
[0032]
The ground plate 1 has the following two openings as structural features.
[0033]
One of the openings is a female screw into which the male screw portion 7011 of the output shaft 701 is screwed so that the output shaft 701 that is the final output shaft of the stepping motor assembly protrudes from the inside of the housing vertically downward. An opening 103 for fixing a female screw member 8 having a portion 801. The female screw member 8 is press-fitted and fixed to the opening 103 of the main plate body 101 of the main plate opening 103, and at the time of this press-fitting, The rubber layer 102 is pressed to ensure a sealing property. Note that a coupling means for mechanically coupling to a controlled valve mechanism (not shown) is provided as a nut member 9 in this example at a portion of the female screw member 8 extending outside the housing. ing.
[0034]
Another opening provided in the main plate 1 is an opening 104 for forming a portion for introducing a power supply line for supplying power and control signals to the stepping motor (hereinafter referred to as “lead wire”). Then, it has the following characteristic structure.
[0035]
That is, the rubber layer 102 as an elastic body constituting the base plate 1 of the present example is provided so that the space 105 is recessed from the base plate opening 104 so that an extension portion 1021 extends from the base plate opening 104 to the inside of the housing. In addition, by sealing the opening of the base plate opening 104 with the sealant application part 106, the void 105 has a characteristic structure in which a space of a new condition that has not existed before is formed. If the feature is specifically described in accordance with this example, the space 105 is spatially located in the housing, but in terms of the sealing structure, the rubber layer 102 is not formed in the housing. There is a feature that the extending portion 1021 is airtightly partitioned and the outside of the housing is airtightly partitioned by the sealant application portion 106.
[0036]
A feed line 303 from the stepping motor 3 is formed in the space 105 that is hermetically partitioned with respect to each of the substantial inside of the housing and the outside air (outside) housing the operation mechanism of the stepping motor assembly. Is extended through the extending portion 1021 of the rubber layer 102 in an airtight manner, and the external power supply line 10 is extended to the space 105 through the sealant application portion 106, The feeder lines 303 and 10 are electrically joined in the space of the space 105. The electrical connection between the pair of power supply lines 303 and 10 can be appropriately performed using a conventionally known connector or the like, and is not shown.
[0037]
By adopting such an electrical connection structure in the void 105, even if there is moisture intrusion through the core portion of the above-described power supply line, this only needs to enter the void 105 and beyond. Intrusion to the stepping motor side is blocked by the extending portion 1021 of the rubber layer 102, and the conventional rare problem of malfunction due to poor hermetic sealing can be solved.
[0038]
A resin molding member 11 is assembled and inserted into the housing of the stepping motor assembly. The support portion 1101 of the extension portion 1021 of the rubber layer 102 that forms the void 105 and the gears 4 and 5 of the gear train. , 6 are provided with fitting holes 1102, 1103, 1104 for supporting the rotating shafts 401, 501, 601 and a loose fitting hole 1105 in which the end of the final output shaft 701 is loosely fitted.
[0039]
Then, fitting holes 1012, 1013, and 1014 are formed in the metal main plate body 101 of the base plate 1 at positions facing these fitting holes 1102, 1103, 1104, and the fitting holes facing each of these pairs. The rotating shafts 401, 501, and 601 of the gears 4, 5, and 6 are fitted and supported. Each fitting hole of the main plate body 101 is formed by press molding, and is shielded from the outside by a rubber layer 102 baked and integrated with the main body 101 to be hermetically sealed.
[0040]
The output shaft gear 7 which is the final output shaft of the stepping motor assembly is engaged with the final gear 6 of the gear train of the speed reduction mechanism, and the rotation of the stepping motor 3 is decelerated and transmitted to rotate. In addition, the male screw portion 7011 is screwed through the female screw portion 801 of the female screw member 8 fixed to the base plate 1 of the housing, so that the rotation is transmitted in the axial direction by the rotation transmission from the stepping motor. While moving forward and backward. At this time, since only the screwing portion is directly involved in the direction of forward / backward movement of the output shaft gear 7, there is no plurality of restraining structures involved in the same movement, so that the output shaft is twisted as in the conventional example. There is no risk of malfunction.
[0041]
A spherical end provided at the tip end (lower end) of the output shaft gear 7 that extends outside the housing presses the valve body of a controlled opening / closing valve (not shown) in the axial direction.
[0042]
Further, a description will be given of the joining relationship of the outer case 2 to be crowned to the substantially flat base plate 1. In this example, the rubber layer 102 is baked by forming the circular base plate peripheral edge 1011 slightly stepped. Occasionally, the rubber layer at the peripheral portion is formed to be slightly thick, and the peripheral portion 201 of the cap 2 formed by drawing a galvanized steel sheet is circulated to the lower side of the base plate to compress the rubber layer 102 at the slightly formed portion. Thus, it is characterized in that the hermetic sealing of the housing composed of the main plate 1 made of the main plate body 101 and the rubber layer 102 and the outer case 2 can be completed by only one step of the above-described caulking process. .
[0043]
In the stepping motor assembly configured as described above, each part can be manufactured by a relatively simple process operation, with the ground plane 1 as a representative, so that the unit price can be reduced and the accuracy of each part can be reduced. The stepping motor assembly can be configured by assembling work by sequentially stacking the parts on the ground plate using these highly accurate parts. There is little advantage that a hermetic seal inside and outside the housing can be realized with a relatively simple assembly operation.
[0044]
Further, since the advancement / retraction of the final output shaft of the stepping motor assembly has no part that restricts the direction of the advancement / retraction other than the axial center of the screwed part with the female screw member, the valve opening / closing degree is controlled. There is no fear of twisting during the tightening operation when the origin is set, and stable use over a long period of time can be realized.
[0045]
【The invention's effect】
As described above, according to the present invention, by reducing the number of parts constituting the stepping motor assembly, the assembly man-hours for the assembly can be reduced, and the cost can be reduced. By making it into the number of processes, the effect that the possibility of a work mistake can be reduced is produced.
[0046]
Further, by further enhancing the hermetic sealing of the outside of the housing of the stepping motor assembly, it is possible to obtain the effect that each requirement from the cold region to the tropical region can be satisfied by the same standard product. In particular, there is an effect that it is possible to effectively prevent problems associated with moisture intrusion through the core portion of the power supply line (lead wire) to the stepping motor.
[0047]
Furthermore, there is no problem such as twisting during the tightening operation to accurately determine the home position in applications where the valve opening / closing degree on the controlled side must be precisely controlled by the forward / backward movement of the output shaft. There is an effect that the possibility of causing a poor advancement / retraction of the shaft is eliminated.
[Brief description of the drawings]
FIG. 1 is an imaginary longitudinal sectional view showing each gear central axis of a gear train of a stepping motor assembly according to a first embodiment of the present invention connected in a plane.
FIG. 2 is a horizontal sectional view of the first embodiment viewed from the bottom side.
FIG. 3 is a longitudinal front view showing an example of a conventional stepping motor assembly.
FIG. 4 is a vertical side view of the conventional example.
[Explanation of symbols]
1: Ground plane
101: Main plate body
1011: (Ground plate) peripheral edge
1012- 1014:
102: Rubber layer
1021: Extension part
103, 104: Opening
105: Empty space
2: Outer case
201: peripheral edge
3: Stepping motor
301: Rotor
3011: spacer
3012: Magnet
3013: Motor pinion
302 rotation axis
303: Feed line (from stepping motor)
4-6: Gear
401-601: Rotating shaft
7: (Final) Output shaft
701: Output shaft
7011: Male screw part
8: Female screw member
801: Female screw part
9: Nut member
10: Feed line (lead wire)
11: Resin molding material
1101: Supporting part
1102 to 1104: fitting holes
1105: Free fitting hole

Claims (6)

A stepping motor, a speed reduction mechanism, a male screw portion provided on the output shaft of the speed reduction mechanism, a female screw member having a female screw portion screwed with the male screw portion, and a ground plate for fixing the female screw member to an outer case A stepping motor assembly comprising a housing for housing the stepping motor and the speed reduction mechanism, and a coupling means provided on the female screw member for mechanical connection to a valve mechanism on the controlled side a is, the ground plate, the inside one only such a substantially flat housing for hermetically sealing from the outside, characterized by being constituted by an elastic body obtained by integrating the product layer on one surface of the base plate main body and its Stepping motor assembly for valve control. A stepping motor, a speed reduction mechanism, a male screw portion provided on the output shaft of the speed reduction mechanism, a female screw member having a female screw portion threadably engaged with the male screw portion, a substantially flat plate, and A housing that forms an internal space partitioned from the outside by an outer case that is crowned on a main plate, and the stepping motor and the speed reduction mechanism that links the stepping motor to the output shaft are housed in the housing, and the female the screw member is provided such that said output shaft is fixed to the base plate of the housing extending the female screw member vertically downwardly screwed through the base plate includes a substantially flat base plate body of the base plate main body provided having a sheet-like elastic member which is integrated to the lower surface, by caulking so Wrapping periphery of the outer case to the elastic body side of the main plate lower surface, the Howe and挾圧the elastic body with the main plate body Space hermetically sealed to as valve control stepping motor assembly, characterized in that a from the outside of the ring. The main plate main body of the main plate is made of a metal member, and the sheet-like elastic body integrated therewith is a rubber member, and the rubber member is integrated with the main plate main body by baking or bonding. The stepping motor assembly for valve control according to claim 2. An opening for introducing a power supply line to a stepping motor is provided in a part of the main plate main body , and the sheet-like elasticity is formed in the housing from the opening of the main plate main body with respect to a space into which the power supply line from outside is inserted. The body is extended to form the cavity in a concave shape, and a terminal electrically connected to one end of the stepping motor is hermetically sealed in the cavity to protrude, and the supply inserted into the cavity from the outside 4. The stepping motor assembly for valve control according to claim 2 , wherein the electric wire and the terminal are electrically connected.   5. The space into which a power supply line is inserted from an opening for introducing a power supply line to a stepping motor provided in a part of the ground plate is hermetically sealed with a sealant. Stepping motor assembly for valve control.   6. A stepping motor for valve control according to claim 2, wherein said female screw member is provided with coupling means for mechanically connecting and fixing to a controlled valve mechanism body. Assembly.

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