JPH0529796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a scroll fluid machine, and more particularly to a structure for preventing lap damage due to an abnormal increase in suction pressure during reverse rotation.

[Background of the invention]

As an example of a scroll fluid machine, a compressor will be explained with reference to FIGS. 1 and 2.

The orbiting scroll 1 has a spiral lap 1b standing upright on an end plate 1a. Also, mirror plate 1
The rear surface of the device a has a rotation bearing 1c and an anti-rotation mechanism (not shown).

Like the orbiting scroll, the fixed scroll 2 has a spiral wrap 2b standing upright on an end plate 2a, and also has a suction port 2c and a discharge port 2d.

The orbiting scroll 1 and the fixed scroll 2 are combined with each other with their laps facing inward, and the orbiting scroll 1 is held between an end plate 2a and a frame 3.

When the orbiting scroll 1 is rotated, the volume of the space formed by the end plate and the lap of the orbiting scroll 1 and the fixed scroll 2 decreases as it moves to the center of the scroll, and the gas sucked from the suction port 2c decreases in volume. is compressed and discharged from the discharge port 2d. FIG. 2 shows a state where suction is completed, and at this time, the outside of the wrap 1b of the orbiting scroll 1 is the suction chamber 2c.
becomes.

Incidentally, in order to compress gas, the orbiting direction of the orbiting scroll must be constant, but in a scroll compressor, the orbiting direction may be reversed. That is, in a scroll compressor,
The pressure of the entire refrigeration cycle may reverse until it is balanced, and since the compressor originally has low pressure on the suction side and high pressure on the discharge side, reversal occurs when the compressor is stopped, and especially when restarted immediately after stopping. is likely to occur.

Therefore, in general, the discharge port 2d or the suction port 2
By providing the backflow prevention mechanism 2f at c, the reverse rotation time is shortened and the normal rotation state is achieved. In the illustrated embodiment, a backflow prevention mechanism 2f is provided at the suction port 2c.

However, even in a compressor with this configuration, if the orbiting scroll is accidentally reversed, the gas entering from the discharge port 2d will be sent one after another to the suction chamber 2e, and the pressure in the suction chamber 2e will decrease. rises abnormally. As a result, a portion 1 of the orbiting scroll 1 that is approximately half a turn from the winding end 1d of the wrap 1b
An excessive stress will be applied over e. This phenomenon becomes more noticeable when the gas contains a large amount of oil or liquid. Therefore, if the gas contains a large amount of liquid, or if it is almost liquid, the liquid is compressed between the outer surface 1f of the winding end and the opposing inner surface 2g of the fixed scroll wrap. Due to liquid compression, excessive stress is applied to the end of the wrap 1b.

On the other hand, the starting part of the scroll wrap is arc-shaped and has relatively high rigidity, but the end part of the scroll has a large radius and is almost like a flat plate, and the end part is cantilevered. Since the wrap is curved, the stiffness of the wrap in this area is small.

Therefore, if the above-mentioned excessive stress is applied to the end of the wrap, which has low rigidity, there is a risk of the wrap being damaged, and if the end of the wrap is damaged, the damage will propagate to the beginning of the wrap. This will result in a situation where

Such a problem may similarly occur in the fixed scroll 2 if the end portion of the lap winding of the fixed scroll 2 has a cantilevered structure.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a scroll fluid machine that can prevent the wrap of an orbiting scroll from being damaged due to an abnormal increase in suction chamber pressure from a reverse rotation state to a normal rotation state.

[Summary of the invention]

In order to achieve the above object, the present invention provides a reversal prevention mechanism for preventing the orbiting scroll from reversing at the suction port, and also provides a direction in the height direction of the wrap from the joint between the wrap and the end plate at the end of the wrap. The wrap is shaped so that the outer side of the wrap bulges out, and the thickness of the wrap in this portion is thicker than in other portions.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. FIG. 3 is a plan view of the orbiting scroll according to the present invention, and FIG. 4 is an enlarged view of section A in FIG. 3. In the figure, at the winding end 1d of the wrap 1b of the orbiting scroll 1, a cylindrical expansion portion 4 is formed over the entire height of the wrap. This bulging portion 4 has a diameter larger than the thickness of the wrap in the height direction from the joint between the wrap and the end plate 1a, and is provided in such a manner that the inner surface of the wrap is connected. There is. Further, the bulging portion 4 is made, for example, by cutting out a lap material.

Therefore, the end portion 1d of the wrap 1b is made thicker and more rigid in the height direction than the other portion where it joins with the end plate of the wrap, so that the wrap is not easily wound when the wrap is reversed. Even if an excessive stress is applied to the end portion, especially the joint portion of the wrap with the end plate, the wrap at that portion will not be damaged. In addition, by forming the cylindrical expansion part 4 at the winding end 1d of the wrap, the winding end 1d
The outer side of the wrap in section d bulges out, but as shown in FIG. 2, the outer side of the wrap from the end of wrap winding 1d to about half the circumference is the suction chamber 2e, so the operation of the orbiting scroll 1 is not affected. There isn't.

In addition, in the present invention, as shown in FIG. 5, a certain range (a to
The bulge 14 may be formed over b). In this case, the stiffness at the end of the wrap is further increased.

In addition, as mentioned above, since the outside of the wrap from the end 1d of the wrap to about half a turn is the suction chamber, as shown in FIG.
The bulging portion 2 extends over a range (a to c) approximately half a turn from
4 can also be formed. In this case, it is possible to leave the outside of the wrap as raw material and omit the processing of the side surfaces. Furthermore, the deformation of the lap when a load is applied is similar to that of a cantilever beam with the head plate as the fixed end, and the maximum application of the joint between the lap and the head plate is exerted. Moreover, if the wall thickness of the wrap is increased over its entire height, the gas passage through the suction port becomes narrower, reducing the performance of the scroll fluid machine. Therefore, it is also possible to increase the thickness of the wrap by a certain height range (depending on the height of the wrap, the thickness of the wrap, and the applied load) from the joint between the wrap and the end plate.

Examples in this case are shown in FIGS. 7 and 8.

FIG. 7 shows an example in which a cylindrical bulge 4' is formed at the end 1d of the wrap 1b from the end plate 1a side to approximately half the height of the wrap 1b.

FIG. 8 shows an example in which a bulge 14' extending over a certain range (a to b) from the winding end 1d of the wrap 1b is formed to approximately half the height of the wrap 1b.

In these embodiments, it is possible to suppress the gas passage loss to a low level, and it is possible to reduce the pressure increase in the suction chamber during reverse rotation.

In addition, although the above embodiment shows an example of the wrap 1b of the orbiting scroll 1, if the end portion of the wrap of the fixed scroll has a cantilever structure, the above-mentioned bulge may be formed at the end portion of the wrap of the fixed scroll. form a section.

〔Effect of the invention〕

As explained above, according to the present invention, in a scroll fluid machine in which a backflow prevention mechanism is provided at the suction port to prevent the orbiting scroll from reversing, the pressure at the suction port abnormally increases due to the orbiting scroll being reversed by mistake. Even in such a case, breakage of the wrap can be prevented, and gas passage loss can be kept small.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a main part of a compressor shown as one of conventional scroll fluid machines, Fig. 2 is a cross-sectional view of Fig. 1, and Figs. 3 and 4 are an embodiment of the present invention. 3 is a plan view of the orbiting scroll, FIG. 4 is an enlarged view of section A in FIG. 3, and FIGS. 5 to 8 show other embodiments of the present invention. FIG. 5 is a plan view of the end of the wrap, FIG. 6 is a plan view of the orbiting scroll, and FIGS. 7 and 8 are perspective views of the end of the wrap. 1...Orbiting scroll, 1a...End plate, 1b...
...Wrap, 1d...End of wrap winding, 2...Fixed scroll, 2a...End plate, 2b...Wrap,
4, 4', 14, 14', 24... bulging portion.

Claims (1)

[Scope of Claims] 1 A device comprising an end plate and a spiral wrap standing upright on the end plate, and the wraps are combined inwardly so that the space formed by each wrap and the end plate moves toward the center. Therefore, an orbiting scroll and a fixed scroll that move relative to each other so as to reduce their volume, compress the gas sucked in from the suction port, and discharge it from the discharge port, and a backflow that is installed at the suction port and prevents the orbiting scroll from reversing. A prevention mechanism is provided, and the outer side of the wrap bulges out in the height direction from the part of the wrap that joins with the mirror plate at the end of winding, and the thickness of the wrap in this part is made thicker than in other parts. A scroll fluid machine characterized by: 2. A scroll fluid machine according to claim 1, characterized in that the thickened portion of the wrap is formed over approximately half the circumference from the end of the wrap.