JP2000329247A - Motor-driven expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a structure by driving a pressing member and a moving member to a valve main body having an orifice with an electric motor to open or close a valve member. SOLUTION: A pulse motor 30 moving a valve member 16 in the valve opening direction via a moving mechanism is fixed to the lower face of a motor fitting member 20, and a coupling piece 31a inserted into a coupling groove section 23c at the lower end of an adjusting shaft 23 is formed on the output shaft 31 of the pulse motor 30. When the rotation of the output shaft 31 is transferred to the adjusting shaft 23 to rotate the adjusting shaft 23, the valve member 16 is converted into a straight motion by a large-diameter screw section 23a and is lifted or lowered, and the valve member 16 approaches an orifice 15 or is separated from it to close or open a motor-driven expansion valve 10. The motor-driven expansion valve 10 is provided with a high-pressure side passage 12, a low-pressure side passage 13 and a low-pressure refrigerant passage 14 on a valve main body 11, its structure is simplified, and the pipe connection to a liquid receiver 4, an evaporator 6 and a refrigerant compressor 2 can be easily made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric expansion valve used for an air conditioner of an automobile, and more particularly to an electric expansion valve for adjusting an opening area of an orifice by a motor.

[0002]

2. Description of the Related Art Conventionally, this type of expansion valve is used for a refrigeration cycle 1 such as an air conditioner of an automobile shown in FIG. That is, the refrigeration cycle 1 includes a refrigerant compressor 2 driven by an engine, a condenser 3 connected to the discharge side of the refrigerant compressor 2, a liquid receiver 4 connected to the condenser 3, and a liquid receiver 4 An expansion valve 5 that adiabatically expands the liquid-phase refrigerant from the air into a gas-liquid two-phase refrigerant, and an evaporator 6 connected to the expansion valve 5. The expansion valve 5 is located in the refrigeration cycle 1.

The expansion valve 5 has a high-pressure side passage 5b through which a liquid-phase refrigerant flows into a valve body 5a and a low-pressure side passage 5c through which an adiabatic expanded gas-liquid two-phase refrigerant flows out. A valve member 8 that communicates the low pressure side passage 5c with the low pressure side passage 5c through an orifice 7, and adjusts the amount of refrigerant passing through the orifice 7.
A low-pressure refrigerant passage 5d is formed through the valve main body 5a, and the temperature-sensitive drive member 9 in which the plunger 9a is slidably fixed in the low-pressure refrigerant passage 5d is fixed to the valve main body 5a. A compression coil spring 8a for pressing in the valve closing direction is provided, and an operating rod 9b for pressing the valve member 8 in the valve opening direction by sliding the plunger 9a is provided.

The plunger 9a of the temperature-sensitive driving member 9
Adjusts the temperature in the low-pressure refrigerant passage 5d to the upper airtight chamber 9c of the temperature sensing part.
The pressure in the upper airtight chamber 9c changes according to the temperature. For example, when the temperature is high, the pressure in the upper airtight chamber rises, and the diaphragm 9d of the temperature sensing part pushes down the plunger 9a to push the valve member 8 down. By moving in the valve opening direction, the amount of refrigerant passing through the orifice 7 is increased to lower the temperature of the evaporator 6. On the other hand, when the temperature is low, the pressure of the upper airtight chamber 9c decreases, the force for pushing down the plunger 9a of the diaphragm 9d of the temperature sensing part weakens, and the plunger 9a rises due to the compression coil spring 8a pressing in the valve closing direction to increase the orifice. The refrigerant passing amount of the evaporator 7 decreases, and the temperature of the evaporator 6 increases.

Thus, the expansion valve 5 is connected to the low-pressure refrigerant passage 5d.
The temperature of the evaporator 6 is adjusted by moving the valve member 8 to change the opening area of the orifice 7 and adjusting the amount of refrigerant passing therethrough. In this type of expansion valve 5, the opening area of the orifice 7 for adiabatically expanding the liquid-phase refrigerant into the gas-liquid two-phase refrigerant is determined by the spring of the compression coil spring 8a that presses the valve member 8 in the valve closing direction at the production stage. This is done by adjusting the pressure.

[0006]

However, in the above-mentioned expansion valve, the temperature-sensitive drive member moves the valve member toward or away from the orifice to adjust the amount of refrigerant passing therethrough, and automatically adjusts the temperature of the evaporator. Therefore, there is a problem that the configuration becomes complicated. Although there is an expansion valve that adjusts the amount of refrigerant passing through a motor, there is a problem in that, for example, when used in an air conditioner of an automobile, piping to a liquid receiver, an evaporator, and a refrigerant compressor becomes complicated. The present invention has been made in view of such a problem, and an object of the present invention is to simplify the configuration and to easily perform piping with an evaporator, evaporator, and refrigerant compressor. An object of the present invention is to provide an expansion valve.

[0007]

In order to achieve the above object,
The electric expansion valve of the present invention is a valve body having an orifice communicating a high-pressure side passage through which a refrigerant flows and a low-pressure side passage through which a refrigerant flows out, a valve member that adjusts an amount of the refrigerant flowing through the orifice, A moving member for moving the valve member, and a pressing member for urging the valve member in the valve opening direction, wherein the moving member is driven by an electric motor to open and close the valve member. . The pressing member is constituted by a compression coil spring, and the moving mechanism is constituted by a screw mechanism for converting a rotational movement of the electric motor into a linear movement.

In the electric expansion valve constructed as described above, the valve member is driven by the electric motor and the electric motor is rotated to one side to bring the valve member closer to the orifice, thereby reducing the flow rate of the refrigerant. When the motor is rotated to the other side, the valve member separates due to the urging of the pressing member in the valve opening direction to increase the opening area of the orifice, thereby increasing the flow rate of the refrigerant. As described above, the flow rate of the refrigerant can be easily adjusted by the valve member using the electric motor, so that the configuration is simplified, and the high pressure side passage, the low pressure side passage, and the low pressure refrigerant passage are provided in the valve body. The piping connection with the evaporator and the refrigerant compressor can be easily performed. Further, by forming the pressing member by a compression coil spring and the moving mechanism by a screw mechanism for converting the rotation of the electric motor, that is, the stepping motor into a linear motion, space efficiency can be improved and the size can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the electric expansion valve of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of the electric expansion valve of the present embodiment in a refrigeration cycle. The electric expansion valve 10 is used, for example, for a refrigeration cycle 1 in an air conditioner of an automobile. The refrigeration cycle 1 includes a refrigerant compressor 2 driven by an engine,
A condenser 3 connected to the discharge side of the refrigerant compressor 2, a receiver 4 connected to the condenser 3, and a liquid-phase refrigerant from the receiver 4 through an orifice having a predetermined opening area for gas-liquid two-phase. It comprises an electric expansion valve 10 for adiabatically expanding the refrigerant by reducing the pressure of the refrigerant, and an evaporator 6 connected to the electric expansion valve 10. The vapor-phase refrigerant in the evaporator 6 is returned to the refrigerant compressor 2 and circulated.

The electric expansion valve 10 has a valve body 11 made of a rectangular parallelepiped metal such as aluminum. A high pressure side passage 12 into which a liquid-phase refrigerant flows, and a gas-liquid 2
A low-pressure side passage 13 through which the phase refrigerant flows out is provided. The high pressure side passage 12 has a hole 12 formed from the bottom of the valve body 11.
a and an opening 12b communicating with the hole and opening on one side of the valve body. The low-pressure side passage 13 is located above the high-pressure side passage 12 and opens on the other side surface of the valve body 11. A low-pressure refrigerant passage 14 is formed in the upper part of the valve body 11 so as to penetrate in the horizontal direction.

An orifice 15 for communicating the high pressure side passage 12 and the low pressure side passage 13 is formed at the center of the inside of the valve body 11. The orifice 15 is a small-diameter circular hole formed from the hole portion 12a of the high-pressure side passage 12, and a connection portion with the high-pressure side passage 12 is formed with a conical valve seat 15a that is salified. The valve member 16 for adjusting the amount of the refrigerant passing through the orifice 15 is composed of a spherical valve portion 17 seated on a valve seat 15a to open and close the orifice 15, and a receiving shaft 18 for fixing the valve portion 17 by welding or the like. , Bearing shaft 1
A step portion for spring receiving is formed on the outer periphery of 8, and
At the center, a drive female screw portion having a lower opening is formed.

An internal female thread is formed on the inner periphery of the lower end opening of the high-pressure side passage 12, and the external female screw on the outer periphery of the central projection of the motor mounting member 20 for closing the lower end opening of the high-pressure side passage 12 is formed in the internal female thread. The parts are screwed and fixed, and an O-ring 21 is mounted between the valve body 11 and the motor mounting member 20. A center hole 22 having an upper large-diameter hole 22a, a central small-diameter hole 22b, and a lower large-diameter hole 22c is formed through the motor mounting member 20, and an adjustment shaft 23 is located inside.

The adjusting shaft 23 has an upper large-diameter screw portion 23a and a lower small-diameter shaft portion 23b, and a slot-shaped engaging groove 23c is formed at the lower end. Motor mounting member 20
The O-ring 24 is doubly fitted between the central small-diameter hole portion 22b of the above and the small-diameter shaft portion 23b of the adjustment shaft 23, thereby ensuring airtightness. The O-ring 24 is prevented from falling off by a retaining ring below the O-ring 24. The receiving shaft 18 is screwed into the large-diameter screw portion 23a of the adjusting shaft 23, and the outer diameter of the receiving shaft 18 is set smaller than the inner diameter of the upper large-diameter hole portion 22a of the motor mounting member 20. It is located in the upper large-diameter hole portion 22a.

The step between the large-diameter screw portion 23a and the small-diameter shaft portion 23b of the adjustment shaft 23 abuts against the end face of the central small-diameter hole portion 22b of the motor mounting member 20 to prevent the adjustment shaft 23 from moving downward. ing. A compression coil spring 26, which is a pressing member, is disposed between the spring receiving step on the outer periphery of the receiving shaft 18 and the upper corner of the high-pressure side passage 12, and moves the valve member 16 away from the orifice 15. That is, it is biased in the valve opening direction. As described above, the high-pressure side passage 12 is configured as a valve chamber in which the valve member 16 and the compression coil spring 26 that urges the valve member in the valve opening direction are located.

On the lower surface of the motor mounting member 20, a valve member 16 is provided.
Motor 3 that moves the valve in the valve closing direction via a moving mechanism
0 is fixed and the output shaft 31 of the pulse motor 30 has an engagement piece 31 inserted into the engagement groove 23 c at the lower end of the adjustment shaft 23.
a is formed. As described above, the rotation of the output shaft 31 of the pulse motor 30 is transmitted to the adjustment shaft 23, and when the adjustment shaft 23 rotates, the valve member 16 is converted into linear motion by the large-diameter screw portion 23a and moves up or down. Is moved toward or away from the orifice 15 to close or open the valve.

In this embodiment, a pulse motor 30 is used as a motor. The pulse motor 30 is controlled by a controller (not shown) having a motor driver, and an output from a temperature sensor (not shown) provided in an evaporator or the like is supplied to the controller. The motor is not limited to the pulse motor, but may be an appropriate motor such as a servo motor. The output shaft may not be directly connected to the motor but may be decelerated via a speed reduction mechanism.

The operation of the electric expansion valve 10 configured as described above will be described below. In refrigeration cycle 1,
The high-pressure refrigerant compressed by the refrigerant compressor 2 driven by the engine is discharged to the condenser 3, radiated and condensed by the condenser 3, and the liquid-phase refrigerant is stored in the liquid receiver 4. Is supplied to the high-pressure side passage 12 of the electric expansion valve 10. In the electric expansion valve 10, the liquid-phase refrigerant is
5, adiabatically expands into a gas-liquid two-phase refrigerant and is supplied to the evaporator 6 from the low-pressure side passage 13. The gas-liquid two-phase refrigerant evaporates in the evaporator 6 to become a gas-phase refrigerant, and keeps the evaporator 6 at a low temperature. Then, the gas-phase refrigerant in the evaporator 6 returns to the refrigerant compressor 2 through the low-pressure refrigerant passage 14, and the refrigerant circulates in the refrigeration cycle 1.

In the refrigeration cycle 1 configured as described above, when it is desired to adjust the temperature of the evaporator 6 to the high temperature side or the low temperature side, the pulse motor 30 is rotated to perform the adjustment. For example, when the pulse motor 30 is rotated forward in the X direction, the engagement piece 31a of the output shaft 31 rotates to rotate the adjustment shaft 2
Turn 3 forward. Then, the large-diameter thread portion 23 of the adjustment shaft 23
a non-rotating valve member 1 which is screwed into a
The orifice 15 is lowered by being pressed by the compression coil spring 26 to increase the opening area of the orifice 15. This makes orifice 1
The amount of refrigerant passing through 5 increases, and the temperature of evaporator 6 is adjusted to a lower temperature.

When the pulse motor 30 is reversely rotated,
The engagement piece 31a of the output shaft 31 rotates to reverse the adjustment shaft 23, and the valve member 16 screwed to the adjustment shaft 23 rises against the compression coil spring 26 to reduce the opening area of the orifice 15. I do. As a result, the amount of refrigerant passing through the orifice 15 decreases, and the temperature of the evaporator 6 is adjusted to a higher temperature. It is also possible to close the valve by bringing the valve member 16 into contact with the orifice 15.

In this way, by operating the pulse motor 30, the valve member 16 is raised or lowered,
The temperature of the evaporator 6 can be adjusted by increasing or decreasing the opening area of the orifice 15 to change the flow rate of the refrigerant.
Since the rotation of the pulse motor 30 can be accurately controlled by a pulse, the relative flow rate of the refrigerant can be accurately adjusted. Further, the electric expansion valve of the present invention has a simple structure because the high pressure side passage 12, the low pressure side passage 13, and the low pressure refrigerant passage 14 are provided in the valve body 11, and the liquid receiver 4, the evaporator 6, and the refrigerant compressor are provided. 2 can be easily connected.

Next, another embodiment of the electric expansion valve of the present invention will be described in detail with reference to the drawings. FIG. 2 is a sectional view of a refrigeration cycle according to another embodiment. In this embodiment, the moving mechanism for moving the valve member in the valve closing direction is changed from the above-described embodiment, so that the configuration thereof will be described in detail, and the other substantially equivalent configurations will be described above. The same reference numerals as in the embodiment are assigned and detailed description is omitted.

A cylindrical motor mounting member 40 for closing the lower end opening is screwed into the mounting female screw formed on the inner periphery of the hole 12a at the lower end opening of the high pressure side passage 12 of the valve body 11 by the outer peripheral thread. The O-ring 40a keeps airtight. The motor mounting member 40 has an upper half located in the valve main body 11, a lower half protruding from the valve main body 11, and a pulse motor 50 mounted on an outer peripheral thread thereof via a nut 50a.

A through hole 41 is formed at the center of the motor mounting member 40, and an adjustment shaft 43 is mounted in the through hole 41 via an O-ring 42 so as to be slidable in the vertical direction. Further, a hexagonal hole 44 is formed on the lower surface of the motor mounting member 40, and the motor mounting member 40 can be mounted on the valve body 11 by inserting a hexagonal wrench into the hexagonal hole. Adjusting shaft 43
A conical hole 45 is formed at the upper end of the lower end of the receiving shaft 18 of the valve member 16 so as to be in contact therewith. A compression coil spring 26 is arranged between the stepped portion of the receiving shaft 18 of the valve member 16 and the upper corner of the high-pressure side passage 12.

The pulse motor 50 has a mounting shaft 51 projecting upward, and a center hole 52 formed of a shaft hole 52a and a screw hole 52b is formed at the center of the mounting shaft. The drive shaft 53 interlocking with the output shaft of the pulse motor 50 is composed of an upper shaft portion, a lower drive screw portion, and a drive ball portion welded to the upper end.
And the drive screw portion is screwed into the screw hole 52b. When the output shaft of the pulse motor 50 rotates, the drive shaft 53 moves up and down by the drive screw portion and the screw hole 52b, and moves the adjustment shaft 43 up and down via the drive ball portion at the upper end. Although not shown, the output shaft of the pulse motor 50 and the drive shaft 53 may have a configuration such as an engagement piece and an engagement groove as in the above-described embodiment.

In the embodiment of FIG. 2 configured as described above, when the output shaft of the pulse motor 50 rotates, the drive shaft 53 is rotated in conjunction therewith, and the drive shaft 53 is driven up and down by a drive screw. The sphere moves the adjustment shaft 43 up and down.
As a result, the valve member 16 moves up and down to come into contact with and separate from the orifice 15, and the opening area of the orifice 15 is changed to adjust the flow rate of the refrigerant.

When the pulse motor 50 rotates forward in the X direction, the drive shaft 53 moves upward, the adjustment shaft 43 moves upward against the urging force of the compression coil spring 26, and the valve member 16 moves to the orifice 15. Because of the approach, the opening area of the orifice 15 is reduced, and the flow rate of the refrigerant is reduced.
Is adjusted to the high temperature side. On the other hand, when the pulse motor 50 rotates in the reverse direction, the drive shaft 53 moves downward, the adjustment shaft 43 moves downward by the urging force of the compression coil spring 26, and the valve member 16 separates from the orifice 15, so that the orifice 15
Of the evaporator 6 is adjusted to a lower temperature side.

As described above, the valve member 16 is brought into contact with or separated from the orifice 15 by the pulse motor 50 and the compression coil spring 26 to adjust the opening area of the orifice, and the flow rate of the refrigerant can be adjusted. can do. The opening area can be adjusted accurately because the pulse motor 50 is controlled by the pulse.

Also, in the electric expansion valve of this embodiment, since the high pressure side passage 12, the low pressure side passage 13 and the low pressure refrigerant passage 14 are provided in the valve body 11, the liquid receiver 4, the evaporator 6, and the refrigerant compressor are provided. 2 can be easily connected. Since the pressing member is constituted by a compression coil spring and a screw mechanism for converting the rotation of the motor into a linear motion is provided inside, the space efficiency can be improved and the size can be reduced.

[0029]

As can be understood from the above description, the electric expansion valve of the present invention is constructed by rotating the electric motor to one side to approach the valve member to reduce the opening area of the orifice, and rotate the electric motor to the other side. Since the valve member can be separated by the pressing member urged in the valve opening direction to increase the opening area of the orifice, the configuration can be simplified. Further, since the high pressure side passage, the low pressure side passage, and the low pressure refrigerant passage are provided in the valve body, the pipe connection with the liquid receiver, the evaporator, and the refrigerant compressor can be easily performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a refrigeration cycle of an embodiment of an electric expansion valve according to the present invention.

FIG. 2 is a sectional view of a refrigeration cycle of another embodiment of the electric expansion valve according to the present invention.

FIG. 3 is a cross-sectional view of a conventional expansion valve in a refrigeration cycle.

[Explanation of symbols]

 Reference Signs List 10 electric expansion valve 11 valve main body 12 high pressure side passage 13 low pressure side passage 14 low pressure refrigerant passage 15 orifice 16 valve member 20, 40 motor mounting member 23, 43 adjusting shaft 26 compression coil spring 30, 50 pulse motor 51 mounting shaft 52 center Hole 53 Drive shaft

Claims (3)

[Claims] 1. A valve body having an orifice communicating a high-pressure side passage through which a refrigerant flows and a low-pressure side passage through which a refrigerant flows out, a valve member for adjusting an amount of the refrigerant flowing through the orifice, and the valve member. In an electric expansion valve including a moving member to be moved and a pressing member for urging the valve member in a valve opening direction, the moving member is driven by an electric motor to open and close the valve member. A characteristic electric expansion valve. 2. The apparatus according to claim 1, wherein said pressing member is constituted by a compression coil spring, and said moving member is constituted by a screw mechanism for converting a rotational movement of said electric motor into a linear movement. The electric expansion valve according to any one of the preceding claims. 3. The electric expansion valve according to claim 1, wherein the electric motor is a stepping motor.