JPH11173448A - Motor-operated valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor-operated valve equipped with a valve element operating mechanism suited for operating a high pressure refrigerant. SOLUTION: The valve seat 351 of a motor-operated valve is integrally formed on a valve main body 32; a valve element comprises a first valve element 361 and a second valve element 362 ; the first valve element 361 is slid in the valve main body 32 so as to be brought into contact/separated with/from the valve seat 351; and the second valve element 362 is so arranged that one end thereof is fitted to the first valve element 361 and the other end thereof is brought into contact with an output shaft 25 through a bush 364 and a spherical body 363. A solid lubricant is applied to the surface of the bush 364, therefore the lubricity of a sliding part can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor-operated valve, and more particularly to a motor-operated valve for transmitting the output of a motor to a valve body via a gear.

[0002]

2. Description of the Related Art Conventionally, a motor-operated valve that transmits the output of a motor to a valve body via a gear has been known as a motor-operated valve. As this kind of electric valve, the electric valve having the configuration shown in FIG.
No. 0-123572. In FIG. 2, a motor 21 is built in a case 20, and a pinion 23 is fixed to a shaft 22 of the motor. Reference numeral 24 denotes a relatively thin gear that meshes with the pinion 23. An output shaft 25 is formed integrally with the gear 24 and has a cylindrical portion 26 at the upper portion and a screw portion 27 at the lower portion, sandwiching the gear.

[0003] A bearing 29 is provided on a partition wall 28 of the case 20, and supports a cylindrical portion 26 of the output shaft 25. A holder 31 is provided on a bottom portion 30 of the case 20, and a screw portion 27 of the output shaft 25 is screwed. Therefore, as described later, when the motor 21 rotates forward and backward, the pinion 23 also rotates forward and backward, and the output shaft 25 also rotates forward and reverse via the gear 24. When the output shaft 25 rotates forward and backward, the output shaft 25
Move up and down by rotation of. At this time, the pinion has a considerable height so that the gear 24 does not separate from the pinion 23.

[0004] Reference numeral 32 denotes a cylindrical valve body, a first passage 33,
There is a second passage 34 communicating with this passage. However, the two passages are respectively connected to the refrigerant pipe. Further, a valve seat 35 is fixed to a communicating portion between the first passage and the second passage by brazing or the like.

[0005] Reference numeral 36 denotes a valve body, the lower end of which faces the valve seat, and the upper end of which contacts the lower end of the output shaft 25. The abutting portion is in the form of a rotatable pivot bearing, and the lower end 37 of the output shaft and the upper end 38 of the valve body, which receive rotational friction, are each hardened by quenching to prevent wear due to friction between them. It is. The valve body 32 is provided with a partition wall 40 having a hole 39 through which the valve body can slide. The bellows 41 has one end on the inner wall of the valve body 32 and the other end on the valve body 36.
Each is attached airtight. However, the holder 31 and the valve body 32 are connected by the nut 42.

In such a configuration, when the motor 21 rotates in one direction, the pinion 23 rotates through the shaft 22,
When the flat gear 24 meshing with the pinion 23 rotates, the output shaft 25 also rotates in one direction. Due to the rotation of the output shaft 25 in one direction, the output shaft moves downward, for example, in FIG. 2, and the valve body 36 that is in contact with the lower end of the output shaft descends against the elasticity of the bellows 41. The flow rate of the refrigerant flowing through the first passage 33 and the second passage 34 is controlled.
The bellows 41 has a function of preventing the refrigerant flowing into the distal end portion of the valve body 36 from entering the motor side. Motor 2
When the output shaft 1 rotates in the other direction, the output shaft 25 rotates in the opposite direction, thereby ascending in FIG.
6 rises by the elasticity of the bellows 41 and controls the flow rate of the refrigerant.

Now, when the valve body 36 is maintained at a predetermined opening relative to the valve seat 35, the first passage 33 and the second passage 34
When the refrigerant flows toward, the refrigerant pressure acts to push up the bellows 41, so that the valve element 36 receives a force in the opening direction in this flow direction. Therefore, output shaft 2
5 operates in a state where it is always pushed upward through the valve body 36.

Conversely, when the refrigerant flows from the second passage 34 to the first passage 33, the valve body 36 receives a load in the direction of arrow opening. It always operates when pushed up. Therefore, the refrigerant always flows into the output shaft 25
The screw portion 27 is pushed upward to flow, so that the flow rate does not change in either the forward or reverse direction, and accurate control can be performed.

[0009]

In such a conventional motor-operated valve, the use of an alternative refrigerant instead of chlorofluorocarbon, which destroys the ozone layer, has been studied from the standpoint of protecting the global environment. As this alternative refrigerant, for example, an HFC (hydrofluorocarbon) -based refrigerant that does not destroy the ozone layer is used.
The use of mixed refrigerants of more than one type is considered promising. However, when the alternative refrigerant is used, the pressure is 1.1 to 1.1 in comparison with the conventional refrigerant that destroys the ozone layer.
When the internal pressure of the valve body is high and the internal pressure is high,
The contact area at the contact portion between the valve body and the output shaft increases,
This leads to an increase in rotational friction. However, when the rotational friction increases, it may be difficult to smoothly slide the valve body in the valve body, and in such a case, there may be a problem that an appropriate valve opening cannot be set.

[0010] Furthermore, wear of the lower end of the output shaft and the upper end of the valve body occurs due to the increase of the rotational friction, and the load on the gears and the bearings increases, and the deterioration may be accelerated. In view of such a point, the present invention provides an electric valve that can secure an appropriate valve opening degree, can perform accurate flow rate control, is excellent in durability, and is highly reliable, even when a so-called alternative refrigerant is used. The purpose is to provide.

[0011]

In order to achieve the above object, a motor-operated valve according to the present invention comprises an output shaft to which the rotation of a motor is transmitted via a gear, one end of which contacts the output shaft, and the other end of which has a valve. A valve body airtightly provided with a bellows which comes into contact with and separates from a valve seat formed in the main body, and a solid lubricant present at a contact portion between the output shaft and the valve body. Slide. In a preferred embodiment of the present invention, the contact portion is a pivot bearing.

Further, the motor-operated valve according to the present invention comprises a valve body,
The rotation of the output shaft of the motor is transmitted via a gear, and the valve body moves up and down in the valve body, a valve seat formed in the valve body in which the valve body comes and goes, and an inner wall of the valve body. One end is attached, the other end is composed of a bellows attached to the valve body, the output shaft and the valve body are in contact with a pivot bearing, and a solid lubricant is applied to the pivot bearing. . In a preferred embodiment of the present invention, a spherical body is used as the pivot bearing, and a solid lubricant is applied to a contact surface between the spherical body and the valve body.

Further, the motor-operated valve according to the present invention has a motor disposed in a case, an output shaft through which the rotation of the motor is transmitted via gears, and screwed with the output shaft to be mounted on the case. A valve body fixed to the holder and having a valve seat, and a valve having one end abutting on the output shaft via a sphere and sliding in the valve body such that the other end faces the valve seat. And a bellows having one end fixed to the valve body and the other end fixed to the inner periphery of the valve body, wherein a solid lubricant is present on a contact surface between the one end of the valve body and the sphere. I do. Also, a preferred embodiment of the present invention is:
A bush for supporting the spherical body is provided at one end of the valve body, and the solid lubricant is present in at least a portion of the bush that contacts the spherical body.

According to the motor-operated valve of the present invention, the solid lubricant is provided at the contact portion between the output shaft and the valve body even when an alternative refrigerant having a higher pressure than the conventional refrigerant is used as the refrigerant for flow control. In addition, the rotational friction can be reduced, an appropriate valve opening can be secured, and the reliability and durability can be improved by reducing wear and the like.

[0015]

FIG. 1 is a longitudinal sectional view showing a main part of an embodiment of the present invention. The basic structure and operation are the same as those of the conventional example shown in FIG. Are different in the configuration of the contact portion between the output shaft provided with the solid lubricant and the valve body. Therefore,
FIG. 1 shows only the main part of the motor-operated valve of the present invention. 1, the same reference numerals as those in FIG. 2 indicate the same or equivalent parts,
The brass valve body 32 is connected to the holder by a nut (not shown) as shown in FIG. 2, the valve seat 351 is formed integrally with the valve body 32, and the valve body 36 is made up of the first valve body 361 and the second valve body 3
The first valve body 361 slides inside the valve body so that one end thereof comes into contact with or separates from the valve seat 351, and the other end thereof is the second valve body 361.
The other end of the valve body 362 is fitted with a bush 364 at one end of the second valve body 362.

The bush 364 constitutes a contact portion between the output shaft 25 and the valve body 361, and is formed in a convex shape using, for example, stainless steel as shown in FIG. , A solid lubricant, for example, “Mori CS” (trade name of Sumiko Lubricant Co., Ltd.) 3
66 are applied in a thickness of a few microns. And
A sphere 363 is disposed in contact with the recessed portion 365 of the bush 364 via a lubricant 366. For example, the sphere 363 made of stainless steel is welded to the output shaft 25 by, for example, spot welding, and the sphere 363 is used as a pivot bearing. ,
It is interposed between the second valve body 362 and the output shaft 25.

In this configuration, the rotation of the output shaft 25 in one direction causes the output shaft to move downward, for example, in FIG. 1, and the sphere 363 moves while rotating, and is in contact with the output shaft via the sphere 363. The second valve body 362 is lowered against the elasticity of the bellows 41, and the first valve body 361 approaches the valve seat 351 to control the flow rate of the refrigerant flowing through the first passage 33 and the second passage 34. I do. In addition, the output shaft 25 is raised in FIG.
The valve body 362 rises due to the elasticity of the bellows 41 and the refrigerant pressure, and the first valve body 361 moves away from the valve seat 351 to control the flow rate of the refrigerant.

In this operation, the valve body 32
Even when the internal pressure of the sphere increases, the sphere 363 can smoothly rotate due to the presence of the solid lubricant 366, preventing an increase in the contact area and preventing an increase in rotational resistance.
The first and second valves can smoothly slide, and the first valve body 361 can accurately contact and separate from the valve seat 351 to realize an appropriate valve opening. Moreover, since the spherical body 363 is disposed on the bush 364 via the solid lubricant 366, the frictional force can be reduced, the spherical body 363 hardly wears, stable operation can be obtained, and high reliability is obtained. A motorized valve can be realized.

Further, in the above-described embodiment, the case where the solid lubricant is applied to the entire surface of the bush 364 has been described. However, the present invention is not limited to this, and the recessed portion 365 of the bush 364 with which the sphere 363 abuts. Needless to say, the solid lubricant may be applied only to the surface. The state of this application is shown by the dashed line in FIG.

Further, in the present invention, the bush 3
Grease (for example, “Moriton CK grease” (trade name of Sumitomo Lubricant Co., Ltd.)) is provided between the solid lubricant 366 and the spherical body 363 applied to the lubricant layer 64 to form a two-layer lubricating layer of grease and solid lubricant. With this configuration, the lubricity of the pivot bearing can be further improved. Further, in the motor-operated valve of the present invention, the holder is made of a high-strength brass material which is a wear-resistant material, so that an increase in wear caused by an increase in refrigerant pressure can be reduced.

[0021]

As described above, according to the motor-operated valve according to the present invention, even if the pressure is increased by the use of the so-called alternative refrigerant, the solid lubricant is provided at the contact portion between the output shaft and the valve body. As a result, the valve body can slide smoothly, secure an appropriate valve opening, and realize accurate flow control.
Wear can be reduced, excellent durability can be obtained, and reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a motor-operated valve according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing the entire configuration of a conventional motor-operated valve.

FIG. 3 is a sectional view showing the structure of the bush shown in FIG. 1;

[Explanation of symbols]

 Reference Signs List 20 case 21 motor 23 pinion 25 output shaft 27 screw portion 32 valve body 35 valve seat 36 valve body 41 bellows 351 valve seat 361 first valve body 362 second valve body 363 sphere 364 bush 366 solid lubricant

Claims (6)

[Claims] 1. A valve body airtightly provided with an output shaft to which rotation of a motor is transmitted via a gear, and a bellows having one end contacting the output shaft and the other end contacting / separating from a valve seat formed on a valve body. When,
An electric valve comprising a solid lubricant present at a contact portion between the output shaft and the valve element, wherein the valve element slides in the valve element. 2. The motor-operated valve according to claim 1, wherein the contact portion is a pivot bearing. 3. A valve body in which rotation of an output shaft of a motor is transmitted via a valve body and a gear, and which moves up and down in the valve body, and a valve formed in the valve body in which the valve body comes into contact with and separates from the valve body. A seat, one end of which is attached to the inner wall of the valve body, and the other end of which comprises a bellows attached to the valve body. The output shaft and the valve body are in contact with a pivot bearing and solid lubrication is applied to the pivot bearing. An electric valve characterized by applying an agent. 4. The electric valve according to claim 3, wherein a spherical body is used as the pivot bearing, and a solid lubricant is applied to a contact surface between the spherical body and the valve body. 5. A motor disposed in a case, an output shaft to which rotation of the motor is transmitted via a gear, a holder screwed to the output shaft and attached to the case,
A valve body fixed to the holder and having a valve seat, one end of which abuts the output shaft via a sphere, and the other end of which slides in the valve body so as to face the valve seat; And a bellows, the other end of which is fixed to the inner periphery of the valve body, wherein a solid lubricant is present at a contact surface between one end of the valve body and the spherical body. 6. The valve according to claim 5, wherein a bush for supporting the sphere is provided at one end of the valve body, and the solid lubricant is present at least at a portion of the bush that contacts the sphere. Electric valve.