JPH0125983B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigerant pressure reducer for an air conditioner used in an air conditioner.

First, a conventional refrigerant pressure reducer for an air conditioner will be explained.

FIG. 1 is a cycle configuration diagram showing an example of a refrigerant circuit of an air conditioner. In FIG. 1, 1 is a compressor, 2 is a first heat exchanger, 3 is a second heat exchanger,
4 is a refrigerant pipe, and 5 is a refrigerant pressure reducer for an air conditioner. The refrigerant pressure reducer 5 for an air conditioner generally uses a thin tube, but it is formed into a loop or spiral shape to save space and make it easy to incorporate into the air conditioner.

However, in actual processing, the bending radius was increased to prevent deformation of the cross-sectional shape of the thin tube and deterioration of performance, so the space efficiency was not as good as expected.

Furthermore, if an external force is applied inadvertently, the thin tubes may be deformed, crushed, or broken, resulting in a serious drawback in that the function as a refrigerant pressure reducer for an air conditioner is impaired.

Furthermore, conventionally, the amount of pressure reduction in a refrigerant pressure reducer for an air conditioner was adjusted by selecting and changing the inner diameter, length, winding radius, etc. of the thin tube depending on the model of the air conditioner. It was not easy to adjust the amount of pressure reduction to the allowable value for the product.

The present invention solves the problems of the prior art described above, has good space efficiency, is strong against external forces, and
The object of the present invention is to provide a refrigerant pressure reducer for an air conditioner, which allows the amount of pressure reduction to be easily adjusted during the formation process.

The configuration of the refrigerant pressure reducer for air conditioners according to the present invention is as follows:
A predetermined length along the length of the pipe is formed by bulge processing into a spiral uneven part in which the inner diameter of the valley part is smaller than the parallel part of the pipe, and the outer diameter is smaller than the inner diameter of the parallel part of the pipe. , a cylindrical core larger than the inner diameter of the valley of the spiral uneven portion,
By press-fitting into the spiral concavo-convex portion, a narrow spiral space is formed between both end surfaces of the core, which communicate with each other.

The present invention will be explained below with reference to Examples.

FIG. 2 is a sectional view of a refrigerant pressure reducer for an air conditioner according to one embodiment of the present invention, and FIG. 3 is a cross section of another embodiment of the core of the refrigerant pressure reducer for an air conditioner according to FIG. It is a diagram.

In FIG. 2, reference numeral 6 denotes a pipe, on the pipe wall of which a single spiral concavo-convex portion 7 is formed, the inner diameter of the trough portion 7b being smaller than the inner diameter of the parallel portion of the pipe 6. 8 is a solid cylindrical core provided in the pipe 6 in contact with the valley portion 7b of the spiral uneven portion 7, and whose length is shorter than the length of the spiral uneven portion 7; , is a narrow spiral space formed between both end faces of the core 8 by the spiral uneven portion 7 and the side wall surface of the core 8. In addition, 7a is a peak part of the spiral uneven|corrugated part 7.

When the refrigerant pressure reducer for an air conditioner configured in this way is incorporated into a refrigerant circuit (not shown) of an air conditioner, the internal cross-sectional area of the pipe through which the refrigerant flows rapidly decreases in the spiral narrow space 9, resulting in pressure reduction. It is effective.

Note that in this embodiment, the spiral uneven portion 7
Although the inner diameter of the valley portion 7b is smaller than the inner diameter of the parallel portion of the pipe 6 (in this case, the length of the core 8 may be longer than the length of the spiral uneven portion 7), The inner diameter of the valley portion 7b of the spiral uneven portion 7 may be larger than the inner diameter of the parallel portion of the pipe 6. However, in this case, since the core 8 must be accommodated within the spiral uneven portion 7, the core 8
The length must be shorter than the length of the spiral uneven portion 7.

In this embodiment, the core 8 is a solid cylinder, but the core 8A is a hollow cylinder with only one end face sealed (Fig. 3), or the core 8A is a hollow cylinder with both end faces sealed. It may also be a child (not shown).

Further, in this embodiment, a single spiral unevenness portion 7 is formed on the wall of the pipe 6, but a plurality of spiral unevenness portions 7 may be formed. By forming a plurality of helical uneven portions, the amount of pressure reduction in the refrigerant pressure reducer for an air conditioner can be made smaller than in the case of a single thread.

Next, a method of manufacturing the refrigerant pressure reducer for an air conditioner according to FIG. 2 will be explained.

FIG. 4 also shows an embodiment of the method for manufacturing a refrigerant pressure reducer for an air conditioner according to the embodiment shown in FIGS. FIG.

In this FIG. 4, 10 is a parallel portion 10a.
and a two-part split outer mold having a groove portion 10b whose inner diameter is smaller than the inner diameter of the parallel portion 10a, 1
Reference numerals 1 and 12 are both seal molds equipped with seal packing 13, and one of the seal molds 12 is provided with an injection hole 12a for pressure medium, which will be described later.

A method for forming spiral unevenness on the wall of the pipe 6 using the vacuum bulge processing apparatus configured as described above will be explained.

First, prepare a pipe 6 having an outer diameter that is approximately the same as the inner diameter of the groove ridge portion 10b of the split outer mold 10, expand the outer diameter of both ends to the inner diameter of the parallel portion 10a of the split outer mold 10, and make the pipe parallel. An enlarged pipe portion 6a is formed according to the section. Seal molds 11 and 12 are inserted into this expanded tube portion 6a, and a split mold 10 is attached to the outside of the pipe 6.

In this state, a pressure medium (for example, pressure oil) is injected from the injection hole 12a to completely fill the pipe 6 with the pressure medium 14, and then a hydraulic pressure 15 is applied by a hydraulic pressure generator (not shown). .

When the hydraulic pressure 15 rises to a predetermined value, the pipe 6 conforms to the split mold 10, and a spiral uneven portion is formed on the wall of the pipe 6.

The pipe 6 is taken out by lowering the hydraulic pressure 15 and removing the split mold 10 and the seal molds 11 and 12.

In this way, the inner diameter of the spiral uneven portion of the pipe 6 can be made smaller than the inner diameter of the expanded portion 6a of the pipe 6 by the amount by which the pipe 6 is expanded.
A helical uneven portion is formed which has a press-fitting allowance (described later) for press-fitting the core 8 (see FIG. 2).

After forming the spiral uneven portion, a solid cylindrical core 8 having an intermediate diameter between the inner diameter of the trough and the inner diameter of the expanded tube portion 6a and a length shorter than the length of the spiral uneven portion, Press fit into the spiral uneven portion (press fit =
The diameter of the core 8 is equal to the inner diameter of the trough of the spiral concave and convex portion), thereby fixing the core 8 to the helical concave and convex portion of the pipe 6. A space 9 can be formed.

Fine adjustment of the amount of pressure reduction can be done using, for example, the method for manufacturing a refrigerant pressure reducer for refrigeration equipment, which was previously developed by the present inventors.
(Japanese Patent Application No. 55-096275) is preferred.

That is, gas is caused to flow into the spiral narrow space 9, the flow path resistance at that time, that is, the amount of pressure reduction is detected, and the outer surface of the spiral concavo-convex portion 7 is cut into a split mold (Fig. (not shown) by partially compressing the spiral narrow space 9
What is necessary is to change the cross-sectional area of .

When significantly changing the amount of pressure reduction depending on the type of air conditioner, in addition to changing the cross-sectional area of the spiral narrow space 9, the pitch and length of the spiral uneven portion 7 may be changed, or the length of the spiral uneven portion 7 may be changed. Keeping the width constant, core 8
What is necessary is to change the length of the helical uneven portion 7, or to make the spiral uneven portion 7 into a plurality of strips.

Note that the method for forming the spiral uneven portion 7 in this example is bulge processing using hydraulic pressure.
Instead of hydraulic pressure, bulge processing may be performed using an elastic body such as rubber, electromagnetic force, or the like.

As described above in detail, the present invention has the following effects.

○A A pressure reducer with good space properties and strong resistance to external forces can be obtained.

○B By partially compressing the outer surface of the spiral uneven portion, the amount of pressure reduction can be easily finely adjusted.

○C Since the core is fixedly held on the inner diameter side by the elastic force of the spiral uneven portion, there is a large margin for press-fitting the core, and the press-fitting operation is easy.
Further, even if there is a dimensional error in the inner diameter of the trough of the spiral uneven portion and the outer diameter of the core, the influence of the error on the fixing and holding force is small, and a stable fixing and holding force can be obtained.

○D Since the pipe itself is formed into a spirally uneven part, regardless of the cross-sectional area of the spiral narrow space, in other words, the height of the unevenness [= (diameter of the peak - diameter of the valley) / 2], the normal A pressure reducer can be made using this pipe. Therefore, for example, when forming a spiral groove on the inner periphery of a pipe, there is no need to use a thick-walled pipe when the height of the unevenness is high, so there is no waste of materials.

○E Since the spiral unevenness is formed by bulge processing, the material is in an unstable state (i.e., a state where it is easy to peel off from the base material, such as curling up) in the troughs (where the core contacts). ) will not occur. Therefore, even if the core is press-fitted, there is no risk that the pipe material will fall off and flow into the refrigerant circuit of the air conditioner.

[Brief explanation of drawings]

FIG. 1 is a cycle configuration diagram showing an example of a refrigerant circuit of an air conditioner, FIG. 2 is a sectional view of a refrigerant pressure reducer for an air conditioner according to an embodiment of the present invention, and FIG. FIG. 4, a sectional view of another embodiment of the core of the refrigerant pressure reducer for air conditioners, is a cross-sectional view of the method for manufacturing the refrigerant pressure reducer for air conditioners according to the embodiments shown in FIGS. 2 and 3 of the present invention. 1 is a cross-sectional view illustrating a main part of a hydraulic bulge processing apparatus directly used therein, also illustrating an embodiment. FIG. 6... Pipe, 6a... Expanded tube part, 7... Spiral uneven part, 7b... Valley part, 8... Core of solid cylinder, 8A... Core of hollow cylinder, 9... Spiral thin space.

Claims (1)

[Claims] 1. A predetermined length along the length of the pipe is formed into a spiral uneven part by bulge processing, the inner diameter of the valley part being smaller than the parallel part of the pipe, and the outer diameter of the pipe being smaller than the parallel part of the pipe. By press-fitting a cylindrical core smaller than the inner diameter of the parallel part and larger than the inner diameter of the trough of the spiral uneven part into the spiral uneven part, between both end surfaces of the core, A refrigerant pressure reducer for an air conditioner, characterized by forming a narrow spiral space that communicates with each other. 2. A refrigerant pressure reducer for an air conditioner according to claim 1, wherein the core is a solid cylinder. 3. A refrigerant pressure reducer for an air conditioner according to claim 1, wherein the core is a hollow cylinder with sealed ends. 4. The refrigerant pressure reducer for an air conditioner according to claim 1, wherein the spiral uneven portion is a plurality of spiral uneven portions.