JPH0718939Y2 - Solenoid expansion valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an electromagnetic expansion valve provided in the middle of a refrigerant passage connecting a condenser and an evaporator of a refrigeration circuit or a cooling circuit.

[Prior Art] Generally, as shown in FIG. 3, a cooling circuit of an air conditioner for an automobile passes from a discharge side 1a of a compressor 1 to a condenser 2, a receiver 3, an electromagnetic expansion valve 4 and an evaporator 5. A circulation circuit of the refrigerant reaching the suction side 1b of the compressor 1 is formed. The electromagnetic expansion valve 4 rapidly expands and vaporizes the liquid refrigerant to lower the temperature of the evaporator 5 for cooling. The opening degree of the electromagnetic expansion valve 4 is set to the outlet side of the evaporator 5. It is changed according to the pressure and temperature of the refrigerant gas, and the cooling capacity of the evaporator 5 is properly maintained. Further, the opening degree is adjusted by operating the plunger by exciting / deactivating the solenoid by the control current.

As shown in FIG. 4, the electromagnetic expansion valve 4 has a valve box 9 fixed to the front portion of a casing 8 of an electromagnet 7, and a valve chamber inside the valve box 9.
10, an inlet portion 11 connected to the outlet side of the liquid receiver 3,
An outlet portion 12 connected to the inlet side of the evaporator 5 is provided. The electromagnet 7 includes a coil 13 and a plunger 14 that can reciprocate linearly, and a needle valve is provided at the tip of the plunger 14.
15 is integrally formed to project. And needle valve
15 is urged toward the closed position by the action of the spring 16,
The demagnetization of the electromagnet 7 causes the plunger 14 to reciprocate to open and close the needle valve 15.

[Problems to be solved by the invention] However, due to the magnetic hysteresis (indicated by a chain double-dashed line in FIG. 5) based on the magnetomotive delay or the remanence, the hysteresis is controlled according to the control current in the opening / closing operation of the electromagnetic expansion valve. There is a gap in the operation. In addition, in a normal electromagnet, a magnetic force that acts accurately on the plunger in the moving direction is not always applied. For example, if a slight error occurs in the winding condition of the coil winding or the shape of the plunger, The magnetic force that is oblique to the moving direction acts on the plunger, which causes the plunger to come into contact with the guide part such as the inner peripheral surface of the valve box during movement, and the friction of the contact part causes the plunger to move intermittently. Therefore, there is a possibility that a continuous and smooth operation cannot be obtained. When the operation shift due to hysteresis overlaps with the discontinuous operation shown by the solid line in FIG. 5, it becomes extremely difficult to operate the electromagnetic expansion valve accurately according to the change in the control current, and the cooling load It is impossible to accurately adjust and control the valve opening according to
There is a problem that control of the cooling capacity causes inconvenience.

The present invention has been made in view of the above problems,
It is an object of the present invention to provide an electromagnetic expansion valve in which the plunger is prevented from coming into contact with a guide portion that guides the reciprocating movement of the plunger and the plunger reciprocates smoothly in response to the excitation / demagnetization of the electromagnet.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, in an electromagnetic expansion valve provided in the middle of a refrigerant passage connecting a condenser and an evaporator, the refrigerant on the condenser side of a valve seat is located. A branch passage is provided in the passage, and an angle formed between the opening of the branch passage and the axial center of the plunger is equal to the circumference of the guide portion that guides the reciprocating movement of the plunger for opening and closing the refrigerant passage. It was provided in at least 3 places at intervals.

[Operation] In the electromagnetic expansion valve of the present invention, a part of the refrigerant flowing through the electromagnetic expansion valve to the evaporator is always supplied to the periphery of the plunger through the branch passages through three or more openings provided in the guide portion. Accordingly, the plunger is held in a state of being separated from the wall surface of the guide portion, and the reciprocating motion of the plunger is smoothly performed.

[Embodiment] An embodiment embodying the present invention will be described below with reference to FIGS. In the device of this embodiment, the structure of the guide portion of the plunger of the portion protruding from the electromagnet is different from the above-mentioned conventional device, and other basic structure is the same as the conventional device,
The same parts are designated by the same reference numerals and the description thereof will be omitted. A branch passage 18 is formed in the refrigerant passage on the condenser side of the valve seat 17 in the valve box 9, and the branch passage 18 is located at a position corresponding to a guide portion 19 for guiding the tip of the plunger 14 as shown in FIG. Annular portion 18a
Is formed, and the plunger 1 extends from the annular portion 18a to the guide portion 19.
Openings 18b are formed at three locations at intervals such that the angle formed with the axis of 4 is equiangular.

Next, the operation of the device configured as described above will be described. When the coil 13 is not energized, the plunger 14 is held by the action of the spring 16 in a position where the needle valve 15 contacts the valve seat 17 shown in FIG. When the coil 13 is energized in this state, the plunger 14 moves leftward in FIG. 1, that is, the needle valve 15 separates from the valve seat 17 by the action of the magnetic force generated in the coil 13. On the other hand, the refrigerant gas flowing from the inlet portion 11 is supplied from the opening portion 18b to the periphery of the guide portion 19 via the annular portion 18a of the branch portion 18 when the needle valve 15 is in contact with the valve seat 17. After the needle valve 15 is separated from the valve seat 17, a part of the refrigerant gas flowing from the inlet portion 11 is supplied to the guide portion 19 through the branch passage 18. The opening 18b formed around the guide portion 19 is the plunger 14
The refrigerant gas acts so as to hold the plunger 14 at the center of the guide portion 19 because the refrigerant gas is arranged so as to form an equal angle with the shaft center. Therefore, when the plunger 14 reciprocates due to energization and de-energization of the coil 13, the plunger 14 moves while floating from the guide portion 19, so that the plunger 14 moves smoothly. Further, since the refrigerant gas contains mist-like oil, the guide 19 is always lubricated with the oil, and even if the plunger 14 comes into contact with the guide portion 19, its frictional resistance is reduced and the plunger 19 is reduced. 14 moves smoothly.

The present invention is not limited to the above embodiment,
For example, the number of openings 18b may be more than three, or the branch passages 18 may be branched corresponding to the number of openings 18b without providing the annular portion 18a in the middle of the branch passages 18.

[Advantages of the Invention] As described in detail above, according to the present invention, when the plunger driving the valve body that opens and closes the refrigerant passage moves due to the excitation / demagnetization of the electromagnet, the refrigerant gas supplied to the guide portion is prevented. The action allows the plunger to move smoothly with almost no static friction between the plunger and the guide portion, and enables accurate control of the electromagnetic expansion valve in the refrigeration circuit or the cooling circuit.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment embodying the present invention, FIG. 2 is an enlarged sectional view taken along the line AA of FIG. 1, FIG. 3 is a circuit diagram of a cooling device, and FIG. 4 is a conventional device. FIG. 5 is a sectional view showing a characteristic of the opening degree of the electromagnetic expansion valve according to the change of the exciting current of the conventional device. Condenser 2, evaporator 5, plunger 14, needle valve 15 as a valve body, valve seat 17, branch passage 18, opening 18b, guide portion 1
9.

Continuation of the front page (56) Reference JP-A-61-70350 (JP, A) Actual flat 1-160278 (JP, U) Actual flat 1-97165 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. An electromagnetic expansion valve provided in the middle of a refrigerant passage connecting a condenser and an evaporator, wherein a branch passage is provided in the refrigerant passage on the condenser side of a valve seat, and an opening portion of the branch passage is provided. An electromagnetic expansion valve provided at at least three locations around a guide portion that guides the reciprocating movement of a valve body driving plunger that opens and closes a refrigerant passage, at intervals such that the angle formed by the plunger axis is equiangular.