JPH0585759B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a scroll type fluid machine, and in particular,
The present invention relates to a scroll type fluid machine having a combination structure of both scrolls to maintain high performance and perform stable operation.

[Prior art]

As an example of a scroll-type fluid machine, the structure of a conventional hermetic scroll compressor will be explained with reference to FIG.

It consists of a scroll-type compression mechanism consisting of an orbiting scroll 1 and a fixed scroll 2 that perform relative orbiting motion, a crankshaft 3, and a frame 4, a motor 5 that drives this, and a casing 6 that houses these.

The orbiting scroll has a spiral wrap 1b on the center of the end plate 1a, an outer peripheral sliding surface 1f on the outer periphery of the end plate 1a, and an anti-rotation mechanism 1c on the back surface for preventing rotation. and a swing bearing 1d into which the crank portion of the crankshaft is inserted.

An orbiting bearing 1d is attached to the end plate 1a of the orbiting scroll.
An oil supply hole 1e that opens at the upper end of the head and the end plate outer peripheral sliding surface 1f is bored.

The fixed scroll 2 also has a spiral wrap 2b on the center of the end plate 2a, and an outer peripheral sliding surface 2f on the outer periphery of the end plate 2a.

Further, the fixed scroll is provided with an inlet 2c and an outlet 2d.

The fixed scroll and the orbiting scroll are assembled with each other with their laps facing inward.

The frame 4 is provided with a notch 4a that has a space in which the end plate 1a of the orbiting scroll can perform an orbiting motion.The outer circumferential portion of the end plate of the orbiting scroll is accommodated in this notch 4a, and the frame and the fixed scroll are fastened to each other. The wrap-free outer peripheral portion of the scroll head plate is held with a slight axial clearance between the upper surface of the notch 4a and the wrap-free outer peripheral sliding surface 2f of the fixed scroll head plate.

A back pressure chamber 4b is formed by a frame on the back surface of the orbiting scroll. The back pressure chamber is communicated with the compression chamber formed by the wrap between the orbiting scroll and the fixed scroll and the end plate through a pressure equalization hole (not shown) provided in the orbiting scroll, and the back pressure is maintained between the suction pressure and the discharge pressure. It is configured to be applied to the back of the orbiting scroll.

The frame is further provided with a bearing 4c for supporting the crankshaft 3 and legs 4d for supporting the motor.

The frame 4 and the fixed scroll 2 are housed in a casing 6, but at this time, a small gap is provided between the frame and the fixed scroll and between the frame and the fixed scroll and the casing to prevent oil and gas from flowing. It is then press-fitted, dividing the inside of the casing into upper and lower halves.

A discharge passage 7 that communicates between the upper and lower parts of the casing is provided on the frame or on the outer periphery of the frame and the fixed scroll.

An oil supply hole 3a is provided in the crankshaft 3 to supply oil from the lower part of the casing to the swing bearing 1d and the bearing 4c.

Due to the rotation of the motor and the action of the crankshaft and anti-rotation mechanism, the orbiting scroll 1 performs an orbiting motion relative to the fixed scroll 2, and the space (compression chamber) formed by the wrap of both scrolls and the end plate is centered. As it moves, its volume decreases, and as a result, the gas sucked in from the suction port 2c is compressed and discharged from the discharge port 2d.

The gas discharged from the discharge port passes through the discharge passage 7 and is discharged from the lower part of the casing to the outside via a discharge pipe (not shown).

When the scroll performs a compression action, a force acts that tends to separate both scrolls. To prevent the orbiting scroll from separating, the pressure in the back pressure chamber of the orbiting scroll is set at an intermediate pressure higher than the suction pressure and lower than the discharge pressure, pressing the orbiting scroll against the fixed scroll.

From the oil supply hole 3a of the crankshaft 3 to the swing bearing 1d,
The oil supplied to the bearing 4c flows into a back pressure chamber whose pressure is lower than the discharge pressure. The oil that has flowed into the back pressure chamber is discharged from the pressure equalization hole in the orbiting scroll to the compression chamber.

Further, oil is supplied from the orbiting bearing 1d to the outer peripheral sliding surface 1f of the end plate of the orbiting scroll through the oil supply hole 1e, and the supplied oil is discharged into the suction chamber 2e.

Conventionally, the crankshaft has been balanced by the pressure inside the casing acting from below and the load due to the oil supply pressure acting on the tip of the crankshaft.

In this structure, when the orbiting scroll and the fixed scroll separate due to various reasons, the amount of oil discharged from the outer peripheral sliding surface 1f of the orbiting scroll end plate into the suction chamber 2e increases, and the pressure acting on the tip of the crank part of the crankshaft increases. decreases. As a result, the balance of the load acting on the crankshaft is disrupted, and the crankshaft is pushed upward, resulting in contact between the crankshaft and the orbiting scroll.

This problem can be solved by providing a thrust bearing to prevent movement of the crankshaft, but the structure becomes complicated.

One of the reasons why the end plate outer peripheral sliding surface 1f of the orbiting scroll separates from the end plate outer peripheral sliding surface 2f of the fixed scroll is the dimensional accuracy of the lap between the fixed scroll and the orbiting scroll.

In the conventional fixed scroll, as shown in FIG. 2, the tooth tip surface 2g of the lap and the outer circumferential sliding surface 2f of the end plate without a lap are machined to be on the same plane.

Also, regarding the end plate of the orbiting scroll, the third
As shown in the figure, the tooth bottom surface 1g of the lap and the outer circumferential sliding surface 1f of the end plate without the lap are machined into the same plane.

When the respective wraps are combined and the end plate outer peripheral sliding surface 1f of the orbiting scroll is brought into sliding contact with the end plate outer peripheral sliding surface 2f of the fixed scroll, the lap tooth bottom surface 2h of the fixed scroll and the lap tooth tip surface 1h of the orbiting scroll are formed. are in opposing sliding contact, and the lap tooth tip surface 2g of the fixed scroll and the lap tooth tip surface 1g of the orbiting scroll are in opposing sliding contact.

However, depending on the machining accuracy, the top surface 2g of the lap teeth of the fixed scroll may partially protrude from the outer peripheral sliding surface 2f of the end plate of the fixed scroll, and the bottom surface 1g of the lap teeth of the orbiting scroll may partially protrude from the outer peripheral sliding surface of the end plate of the orbiting scroll. 1f, these partial protrusions cause the orbiting scroll and the fixed scroll to come into contact with the lap tooth bottom surface 2h of the fixed scroll and the lap tooth tip surface 1h of the orbiting scroll, or cause the fixed scroll to The lap tooth tip surface 2g of the scroll and the lap tooth tip surface 1g of the orbiting scroll are in contact, so that a gap is created between the end plate outer circumferential sliding surface 2f of the fixed scroll and the end plate outer circumferential sliding surface 1f of the orbiting scroll. become. In a state where such a gap is formed, the above-mentioned excessive amount of oil flows out, making it impossible to obtain stable operation and resulting in a decrease in reliability and performance.

[Purpose of the invention]

The present invention has been made to solve the problems in the prior art described above, and its purpose is to create a gap between the outer peripheral sliding surfaces of each end plate without laps when an orbiting scroll and a fixed scroll are combined. An object of the present invention is to provide a scroll-type fluid machine that can obtain stable operation without causing any problems.

[Structure of the invention]

In order to achieve the above object, a scroll type fluid machine according to the present invention has a spiral wrap provided upright in the center of each head plate, and a sliding surface on the outer periphery of the head plate that is in mutual sliding contact with the outer periphery of the head plate. an orbiting scroll and a fixed scroll having the same shape, combined with each other with their laps facing inward,
In a scroll-type fluid machine configured such that both scrolls move relative to each other so that the volume of the space formed by each lap and end plate decreases as it moves toward the center of the scroll, Both scrolls are recessed by either recessing the surface by a minute step difference from the outer peripheral sliding surface of the fixed scroll end plate, or recessing the bottom surface of the lap teeth of the orbiting scroll by a minute step difference from the outer peripheral sliding surface of the orbiting scroll end plate. When combined so that the outer peripheral sliding surfaces of each end plate are in sliding contact with each other, there is a minute gap between the top surface of each lap tooth and the bottom surface of the lap tooth of the opposing scroll over the entire length of both scroll wraps. The invention is characterized in that it is configured such that a.

[Embodiments of the invention]

Examples will be explained with reference to FIGS. 4 to 9.

Note that the overall structure is the same as the conventional one, so a description thereof will be omitted.

An example of implementation is shown in FIGS. 4 and 5.

On the end side of the lap of the fixed scroll, a minute step is provided between the lap tooth tip surface 2g and the end plate outer peripheral sliding surface 2f without a lap, and the orbiting scroll is the same as the conventional one.

Due to this step, between the lap tooth top surface 2g of the fixed scroll and the lap tooth bottom surface 1g of the orbiting scroll, the end plate outer circumferential sliding surface 2f of the fixed scroll and the end plate outer circumferential sliding surface 1f of the orbiting scroll slide into contact with each other. In this case, a gap corresponding to the above-mentioned step difference can be secured.

As shown in Fig. 6 and Fig. 7, this structure is based on the sliding surface 2f of the fixed scroll on the outer periphery of the end plate without any wraps.
Alternatively, a ring-shaped separate sliding surface member 2j slightly protruding from the outer circumferential surface 2f may be installed over the entire area or part of the outer circumferential surface 2f.

In this case, the end plate outer peripheral sliding surface 1 of the orbiting scroll
Since f is slidably supported by the ring-shaped separate member 2j, a minute gap can be provided between the top surfaces of the lap teeth of both scrolls and the bottom surfaces of the lap teeth of the corresponding mating scroll.

Another embodiment is shown in FIGS. 8 and 9.

A minute difference in level is provided on the mirror plate surface of the orbiting scroll at a portion corresponding to the lap tooth top surface 2g of the fixed scroll, that is, between the lap tooth bottom surface 1g of the orbiting scroll and the mirror plate outer peripheral sliding surface 1f without laps. Note that in this case, the fixed scroll is the same as the conventional one.

Since the end plate outer peripheral sliding surface 1f of the orbiting scroll is supported by the end plate outer peripheral sliding surface 2f of the fixed scroll, there is a gap between the lap tooth top surface 2g of the fixed scroll and the lap tooth bottom surface 1g of the orbiting scroll. A corresponding clearance is maintained.

In either embodiment, a minute clearance is ensured at the tip of the lap of the orbiting scroll and fixed scroll, so that the above-mentioned partial protrusion of the top surface 2g of the lap tooth of the fixed scroll or partial protrusion of the bottom surface 1g of the lap tooth of the orbiting scroll is ensured. It is possible to prevent an unnecessary gap from being generated between the orbiting scroll end plate outer circumferential sliding surface 1f and the fixed scroll end plate outer circumferential sliding surface 2f, which would have been caused due to the protrusion. Therefore, it is possible to prevent excessive oil from leaking around the outer circumference of the end plate of the orbiting scroll and gas leaking into the suction chamber from the back surface of the end plate.

The structure described above will be even more effective if one or both of the scrolls is surface treated so that at least a soft material with conformability is attached to the tip of the lap tooth, in addition to this basic structure. become a target.

That is, the gap at the lap tooth top surface can be kept small, and contact with the lap tooth top surface can be prevented by the conformation of the soft material.

〔Effect of the invention〕

According to the present invention, conventionally, depending on the machining accuracy, the lap tooth tip surface partially comes into contact with the tooth bottom surface of the mating scroll. Unnecessary separation from the sliding surface can be completely prevented. As a result, it is possible to prevent an excessive amount of oil from flowing out on the outer periphery of the end plate of the orbiting scroll, and stable operation can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the overall structure of a conventional scroll compressor, Fig. 2 is a sectional view showing a conventional fixed scroll, Fig. 3 is a sectional view showing a conventional orbiting scroll, Figs. The figures are top views showing fixed scrolls according to embodiments of the present invention, Figures 5 and 7.
8 is a top view showing an orbiting scroll according to an embodiment of the invention, and FIG. 9 is a sectional view showing an orbiting scroll according to an embodiment of the invention. 1... Orbiting scroll, 1a... End plate, 1b... Wrap, 1c... Rotation prevention mechanism, 1d... Orbiting bearing, 1e
...Oil supply hole, 1f...Sliding surface on the outer periphery of the end plate of the orbiting scroll, 1g...The bottom surface of the lap tooth of the orbiting scroll, 1h
...Lap tooth tip of orbiting scroll, 2...Fixed scroll, 2a...End plate, 2b...Lap, 2c...Suction hole, 2d...Discharge hole, 2e...Suction chamber, 2f...Sliding surface on outer periphery of fixed scroll end plate, 2g... Fixed scroll lap tooth top surface, 2h... Fixed scroll lap tooth bottom surface, 2j... Ring-shaped separate body, 3... Crankshaft, 3a... Oil supply hole, 4... Frame, 4a... Notch, 4b... Back pressure chamber, 4e ...bearing, 4d...leg, 5...
Motor, 6...Casing, 7...Discharge gas passage.

Claims (1)

[Scope of Claims] 1. An orbiting scroll and a fixed scroll having a spiral wrap provided upright in the center of each end plate, and having an outer peripheral sliding surface of the end plate that slides on the outer periphery of the end plate, A scroll-shaped fluid having a structure in which both scrolls are assembled with their wraps facing inward, and the scrolls are moved relative to each other so that the space formed by each wrap and end plate decreases in volume as it moves toward the center of the scroll. In the machine, should the top surface of the lap teeth of the fixed scroll be recessed by a minute difference in height from the sliding surface around the outer periphery of the fixed scroll end plate, or should the bottom surface of the lap teeth of the orbiting scroll be recessed by a difference in step distance from the outer periphery sliding surface of the orbiting scroll end plate. When both scrolls are combined so that the outer circumferential sliding surfaces of their end plates are in sliding contact with each other, the top surface of each lap tooth and the opposing scroll wrap are formed over the entire length of both scroll wraps. A scroll-type fluid machine characterized by being configured so that a minute gap is formed between the lap tooth bottom surface and the bottom surface of the lap tooth. 2. The recess corresponding to the minute step difference on the top surface of the lap tooth of the fixed scroll is a ring-shaped recess for the sliding surface to create the minute step difference between the end surface of the end plate of the fixed scroll and the top surface of the lap tooth of the fixed scroll. The scroll-type fluid machine according to claim 1, wherein the scroll-type fluid machine is formed by installing a separate body. 3. The scroll-type fluid machine according to claim 1 or 2, characterized in that at least one or both lap tooth tips of the scroll are subjected to a surface treatment to provide conformability.