JPH0460188A - Scroll type fluid machine - Google Patents

Abstract

PURPOSE:To well provide a seal between an end plate and a lap end from starting time so as to contrive improvement of starting characteristic by providing a passage for connecting lap space in a delivery side, formed between combined laps, to a back pressure chamber in the end plate of a fixed scroll. CONSTITUTION:In a scroll compressor, a turning scroll 9 makes a turning motion while restricting the revolution on its own axis by an Oldham's mechanism 15 through a rotary shaft 5 by driving a motor 2. A refrigerant, sucked from a suction pipe 27, is compressed and delivered to a delivery path 5b from a delivery hole 28 by changing the volume of closed space 23 between laps 11, 21 periodically to a contraction side in accordance with a position toward the center side from the peripheral side according to this turning motion. Here, the refrigerant, reaching the closed space 23 of the final step, is partly delivered to a back pressure chamber 31 through a port 32, so that a fixed scroll 19 is pressed from a back surface side to the turning scroll 9 so as to prevent protruding ends of the laps 11, 21 from separating from end plates l0, 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) This invention relates to a scroll-type fluid machine having a fluid machine section that combines a fixed scroll and an orbiting scroll.

(Prior art) Scroll compressors (scroll-type fluid machinery) used in refrigeration cycle devices such as air conditioners and refrigerators are conventionally equipped with an in-case high-pressure type % type that combines a fixed scroll and an orbiting scroll. A scroll compressor uses a fixed scroll and an orbiting scroll, each having a spirally formed wrap protruding from one side of an end plate. and,
A compressor section (fluid machine section) is constructed by combining these fixed scrolls and orbiting scrolls with their centers shifted so that their wraps are inserted into each other alternately. This compressor section is housed in a sealed case together with the electric motor section that drives the compressor section, and the compression process is performed by rotating the orbiting scroll around the axis relative to the fixed scroll. It looks like this. In other words, the volume of the crescent-shaped sealed space (wrap chamber) formed between the wrappings that wrap together shrinks periodically from the outer circumference toward the center in accordance with the orbiting motion of the orbiting scroll. This is used to suck in refrigerant (suction gas) from the outer circumferential side of the scroll and compress it. Then, the compressed refrigerant is discharged into the sealed case from the discharge hole in the center, and then discharged out of the case.

By the way, in order to ensure such performance, it is necessary to improve the seal between the end plate and the wrap.

For this reason, conventional scroll compressors have been provided with a sealing member at the protruding end of the wrap.

But even this is not enough.

Therefore, recently, a scroll compressor has been proposed in which a fixed scroll is pressed against an orbiting scroll using compressed fluid to obtain a high seal.

As shown in FIG. 2, a fixed scroll b of a compressor section a is supported movably along the axial direction by a frame portion C provided around the fixed scroll b. Further, a back pressure chamber e, which is used as a part of the end plate d, is formed between the back surface of the end plate d of the fixed scroll b and the frame portion C facing thereto.

In order to apply the discharge pressure (positive pressure) generated in the compressor section a, a frame section C and a sub-frame cover h, which are located around the fixed scroll b and the orbiting scroll f, are placed above the compressor section a. Case space g and compressor part a
A through groove m is provided which communicates with the space which becomes the oil reservoir in the lower part of the rotary scroll f, and the pressure of the discharged refrigerant discharged from the discharge hole n of the orbiting scroll f through the inside of the rotating shaft p into the case space g is controlled. Guide it to the oil sump k. At the same time, a cover h constituting the wall surface of the back pressure chamber e is provided with a port q for guiding the discharge pressure applied to the oil reservoir k into the back pressure chamber e.

In other words, by guiding the discharge pressure in the sealed case r to the back pressure chamber e, the fixed scroll b is pressed against the orbiting scroll f,
I try to keep a seal between the two.

(Problem to be solved by the invention) However, the volume of the case space f of a hermetic compressor can be reduced by using lubricating oil contained in the discharged refrigerant.
In order to maintain the function of cooling the scroll, it is relatively large, and as the pressure in the case space g becomes high, back pressure is applied to the fixed scroll b.

For this reason, the above-mentioned structure for guiding the discharge pressure from inside the sealed case r to the back pressure chamber e requires that the pressure inside the sealed case r become high before the necessary pressure is applied to the back surface of the fixed scroll b. do not. In other words, there was a drawback that the fixed scroll b could not be immediately pressed against the orbiting scroll f at the time of startup.

Therefore, compressors employing the above structure did not have good sealing performance during startup and had poor startup characteristics.

This invention was made with attention to these circumstances,
The object is to provide a scroll-type fluid machine that can provide good sealing between the end plate and the wrap end from the time of startup.

[Structure of the Invention (Means for Solving the Problems)] In order to achieve the above object, the scroll type fluid machine of the present invention has a discharge side formed between the mating wraps on the end plate constituting the fixed scroll. A passage communicating between the wrap space and the back pressure chamber is provided to constitute back pressure supply means for guiding the positive pressure generated in the fluid machine section to the back pressure chamber.

(Function) According to the scroll-type fluid machine of the present invention, as the fluid machine section operates, the pressure on the discharge side between the laps generated in the fluid machine section passes through the passage of the end plate of the fixed scroll to create back pressure. He is led into a room. This means that the pressure on the discharge side acts directly on the back pressure chamber, pressing the fixed scroll against the orbiting scroll side, without passing through the sealed case, which causes a delay in pressure transmission. .

Therefore, it is possible to operate with the end plate and the wrap end sealed by back pressure immediately upon startup, and it is possible to improve the startup characteristics.

(Example) The present invention will be described below based on an example shown in FIG. FIG. 1 shows an in-case high-pressure type scroll compressor used, for example, in a refrigeration cycle device to which the present invention is applied, and in the figure, 1 is a vertically elongated sealed case. A motor 2 (electric motor section) is provided in the upper part of the sealed case 1. The motor 2 includes a stator 3 fixed to the inner peripheral surface of the case, and a rotor 4 disposed inside the stator 3. Note that a rotating shaft 5 serving as a rotor shaft is attached to the axial center of the rotor 4 by press fitting.

Reference numeral 6 denotes a substantially disk-shaped frame arranged in the middle of the sealed case 1. The frame 6 is attached to the inner peripheral surface of the sealed case 1.
It is attached so as to partition the inside of the sealed case 1 into upper and lower parts. In addition, a cylindrical bearing portion 7 is provided at the center of the upper surface of the frame 6.
is installed protrudingly.

The lower end portion of the rotating shaft 5 is slidably inserted into the second bearing portion 7 . A compressor section 8 (fluid machine section) is provided at the lower end of this rotating shaft 5.

To explain this compressor section 8, 9 is an orbiting scroll. The orbiting scroll 9 has a spiral wrap 11 formed by bending a band into a spiral (involute, etc.) protruding from the entire lower surface of a disc-shaped end plate 10 placed at the center of the lower surface of the frame 6. It is constructed by protruding a pivot shaft 12 from the center portion. The rotating shaft 12 is rotatably fitted into a fitting hole 13 eccentrically provided in the large diameter portion 5a at the lower end of the rotating shaft 5, and the rotating scroll 9 is positioned at the center of the rotating shaft 5. It is placed. Thereby, the orbiting scroll 9 comes to revolve around the axis of the rotary shaft 5 according to the operation of the motor 2. The back surface of the orbiting scroll 9 is slidably supported by a thrust bearing section 14 that protrudes around the recess of the frame 6 in which the orbiting shaft 12 is embedded.

Further, an Oldham mechanism 15 is provided around the thrust bearing portion 14. The Oldham mechanism 15 includes, for example, the pivot shaft 1
A pair of key grooves 16 and 16 are arranged along the same diametrical direction on the lower surface portion of the frame 6 corresponding to two points in the diametrical direction passing through the axis of the pivot shaft 12 on the locus of a circle centered on the axis of the rotating shaft 12. (
Furthermore, a pair of key grooves 1717 (only one of which is shown in the figure) are provided along the same diametrical direction on the top surface of the end plate]0 corresponding to two points on a circular locus passing in a direction perpendicular to this direction. (No). Then, between the mirror plate 10 and the frame 6, each key groove 16°1, 6. 1. ,7.
1.7 and two pairs of keys 16a that can be slidably inserted;
16a, 17a, 17a (only one of which is shown) is interposed. Then, each key 16a, 17a and each key groove 1
6. To allow for the amount of eccentricity obtained by sliding in step 17, the orbiting scroll 9 is rotated without rotating on its own axis.

A fixed scroll 19 is combined with this orbiting scroll 9 to constitute a compressor section 8. That is, the fixed scroll 19 has a wrap 21 having the same external shape as the wrap 11 of the orbiting scroll 9 protruding from the upper surface of an end plate 20 formed in a disk shape, and a short cylindrical protrusion 22 at the center of the lower surface which becomes the back surface. It has a protruding structure. And this fixed scroll 1
The laps of the orbiting scroll 9 and the orbiting scroll 9 are combined so as to be offset from the center and inserted into each other alternately. Specifically, the wraps 11 and 21 are engaged with each other at a position where the axial center of the fixed scroll 19 matches the axial center of the rotating shaft 5. This combination forms a crescent-shaped sealed space 23 between the wraps 11 and 21.

A circular flat plate-shaped cover 24 serving as a sub-frame is attached to the outer periphery of the lower surface of the frame 6 so as to surround the orbiting scroll 9 and the fixed scroll 19. and,
The orbiting scroll 9 is rotatably housed in a housing space 25 formed by a concave space of the cover 24. At the same time, a fixed scroll 19 to be combined therewith is housed so as to be movable along the axial direction. That is, a recess 26 into which the protrusion 22 of the fixed scroll 19 is slidably inserted is provided at the center of the bottom surface of the housing space 25 . And this recess 2
The inner circumferential surface of 6 and the outer circumferential surface of the protrusion 22 are connected to be slidable in the axial direction by, for example, a spline structure, so that the fixed scroll 19 can be displaced only in the axial direction without rotating. be.

A suction pipe 27 that communicates with the housing space 25 is connected to the peripheral wall of the cover 24, so that refrigerant can be sucked in as the orbiting scroll 9 rotates.

A discharge hole 28 is provided in the center of the end plate 10 of the orbiting scroll 9 and opens into a closed space 23 (corresponding to a wrap chamber on the discharge side) which is the final stage of the compression process. The discharge hole 28 is connected to the discharge passage 5b provided at the axial center of the rotating shaft 5 and the upper space in the sealed case 1.
It communicates with a discharge pipe 29 connected to the upper part of the sealed case 1, so that the refrigerant discharged from the discharge hole 28 can be discharged to the outside from the discharge pipe 29 through the case space.

On the other hand, an O-ring 30 is interposed between the outer peripheral surface of the protrusion 22 and the inner peripheral surface of the four parts 26. Then, with the 200 ring 30, the accommodation space 25 on which the suction pressure acts is blocked, and the space surrounded by the protrusion 22, the rear surface of the end plate 20, and the four parts 26 at the central part of the back of the end plate 20 is filled with
A back pressure chamber 31 is configured. Also, in the center of the end plate 20 of the fixed scroll 19, there is a port 32 (
A passageway) is provided. This allows discharge pressure (positive pressure) to be directly introduced into the back pressure chamber 31 (back pressure supply means). In other words, the fixed scroll 19 can be pressed against the orbiting scroll 9 by the pressure applied to the back pressure chamber 31.

Note that 33 is an oil reservoir formed on the upper surface of the frame around the bearing 7, 34 is an oil reservoir formed between the cover 24 and the bottom of the sealed case 1, and 35 is the frame 6 and the cover. The oil reservoir portion 3 provided on the outer peripheral portion of 24
3.34 A lubricating oil passage for communicating with each other, and 36 is lubricating oil filled in oil reservoirs 33 and 34.

Next, the operation of the scroll compressor configured in this way will be explained.

When the motor 2 is excited, the rotor 4 rotates, and this rotation is transmitted to the orbiting scroll 9 via the rotating shaft 5.

Here, rotation of the orbiting scroll 9 is restricted by an Oldham mechanism 15. Therefore, the orbiting scroll 9 rotates around the axis of the fixed scroll 19 (the axis of the rotating shaft 5) without rotating.

Along with this turning movement, the closed space 2 between the wraps 11 and 21
In No. 3, the volume periodically changes from the outer circumferential side toward the center side. Due to this change in volume, the refrigerant sucked from the suction pipe 27 is compressed. Then, the refrigerant reaching the final stage of the sealed space 23 is discharged from the discharge hole 28 to the discharge passage 5b. Next, this refrigerant is guided to the upper space of the sealed case 1 and then discharged to the outside from the discharge pipe 29.

On the other hand, a part of the refrigerant reaching the final stage sealed space 23 is discharged into the back pressure chamber 31 through the port 32. Then, the pressure (discharge pressure) of the refrigerant introduced into this back pressure chamber 31 presses the fixed scroll 19 from the back side and displaces it along the axial direction, causing the protruding ends of the wraps 11.21 and the end plate 10.
20, press it against the orbiting scroll 9 so that it does not come off.

Therefore, the pressure on the discharge side is directly transferred to the back pressure chamber 31 without passing through the sealed case 1, which causes a delay in pressure transmission.
This means that it can be made to act on

Therefore, from the time of startup, the mirror plate 10, 20 and wrap 1 are immediately connected.
It is possible to operate with the protruding end of 1.21 sealed by back pressure, and the starting characteristics can be improved.

In the above embodiment, the discharge pressure is guided to the back pressure chamber 31, but the invention is not limited to this, and the present invention can be applied to a compressor in which refrigerant at a pressure in the middle of compression, that is, an intermediate pressure, is guided to the back pressure chamber 31. You may. Furthermore, the discharge hole 28 of the orbiting scroll 9 may be eliminated by using a structure in which the refrigerant introduced into the back pressure chamber 31 is discharged into the sealed case 1.

Further, although the present invention has been applied to a scroll pump in each of the above embodiments, the present invention is not limited to this, and can be applied to scroll-type fluid machines such as a scroll compressor that combines a fixed scroll and an orbiting scroll, a scroll-type expander, etc. It's okay.

raising, 26... recess, 28... discharge hole, 30...0
Ring, 31... Back pressure chamber, 32... Port (passage)
.

[Effects of the Invention] As explained above, according to the present invention, it is possible to perform good sealing between the end plate and the wrap end from the time of startup, and it is possible to improve the startup characteristics.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a scroll compressor according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional scroll compressor.

Claims (1)

[Claims] A fluid machine section consisting of a fixed scroll with a spiral wrap protruding from one side of an end plate and an orbiting scroll combined so that the wraps are inserted alternately is placed in a sealed case together with an electric motor section that drives the fluid machine section. accommodated in
This fixed scroll is supported movably along the axial direction by a frame provided around the fixed scroll, and a back pressure chamber is provided on the back side of the fixed scroll facing the back of the mirror plate. In a scroll-type fluid machine configured by providing a back pressure supply means for guiding positive pressure generated in the fluid machine section to a back pressure chamber, the back pressure supply means is attached to an end plate constituting the fixed scroll. A scroll-type fluid machine characterized in that a passage is provided that communicates a discharge-side wrap space formed between wraps with the back pressure chamber.