JPS62291401A - Scroll type fluid machine - Google Patents

Abstract

PURPOSE:To reduce the sliding friction loss, by forming a groove having a width creating a dynamic pressure effect during the revolution of a revolving scroll, on a sliding surface receiving a thrust of the revolving scroll. CONSTITUTION:In a scroll type fluid machine having fixed and revolving scrolls 3 and 6 provided with laps 2 and 5 of an involute shape or the like upright standing from specular plates 1 and 4, the laps 2 and 5 of the scrolls 3 and 6 are meshed with each other, and the revolving scroll 6 is revolved relative to the fixed scroll 3 without apparently being rotated, thereby boosting a liquid sucked from a low pressure port 9 and discharging same from a high pressure port 8. A sliding surface of the specular plate 1 of the fixed scroll 3 is formed with an annular groove 13 concentric with the fixed scroll 3. The groove 13 has a width creating a dynamic pressure effect during the revolution of the revolving scroll 6. Further, the specular plate 1 is formed with an oil supply hole 10 communicated with the groove 13.

Description

[Detailed description of the invention] 3. Detailed description of the invention [Industrial application field] The present invention relates to a scroll type fluid machine.

[Conventional technology]

A scroll-type fluid machine consists of two scrolls formed by standing upright spiral wraps made of involute curves on an end plate, which are engaged with each other with the wraps facing each other. When the member is arranged and used, the high pressure port becomes a discharge port, and when used as an expander and a motor, the high pressure port becomes an inlet for working fluid.

In such a scroll-type fluid machine, in order to prevent the scrolls from separating due to the pressure of the fluid trapped between both scrolls, (1) As shown in U.S. Pat. No. 3,817,664, Force (gas pressure, spring pressure, or a combination of both) is applied to the surface on the opposite side of the orbiting scroll (hereinafter referred to as the back surface).

(2) As shown in Japanese Patent Application Laid-Open No. 53-35840, a thrust bearing is arranged on the opposite side of the orbiting scroll. We have prepared one treatment for each corner.

[Problem that the invention seeks to solve]

In the former method, the orbiting scroll is pressed against the fixed scroll (stationary part), so the sliding friction loss between them becomes large, while in the latter method, the sliding scroll between the thrust bearing (stationary part) and the orbiting scroll increases. Dynamic friction loss increases.

An object of this invention is to reduce sliding friction losses between an orbiting scroll and a stationary part.

[Means for solving problems]

The feature of this invention is that the sliding surface that receives the thrust acting on the orbiting scroll has a groove, and the depth of this groove is formed to a depth that generates a dynamic pressure effect when the orbiting scroll makes an orbiting motion. There is a particular thing.

[For production]

With the above configuration, when the orbiting scroll makes an orbiting motion, a slight inclination of the orbiting scroll causes a wedge action by the oil in the groove, and the orbiting scroll receives the wedge action from the sliding surface that receives the thrust of the orbiting scroll. It rotates in a slightly raised state. Therefore, friction loss due to sliding can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. 1, 2, and 3 show a first embodiment of this invention.

The fixed scroll 3 includes an end plate 1 having an annular sliding surface IA (this sliding surface IA serves as a sliding bearing) on the outer periphery, and an involute curve or a curve approximating this, standing upright on the end plate 1. The fixed scroll 3 has a high-pressure port 8 in the center thereof and a low-pressure port 9 outside the wrap 2. The sliding surface IA of the end plate 1 of the fixed scroll 3 is provided with an annular groove 13 centered on the axis of the fixed scroll 3. Hole 10 (10a, 10b, 10c, '10d)
It is equipped with The groove 13 is formed to have a constant width and a depth of, for example, 100 microns or less so that a dynamic pressure effect occurs. One condition for the hydrodynamic effect to occur is that the orbiting scroll is tilted (the bottom of the annular groove 13 is tilted with respect to the sliding surface IA of the fixed scroll 3). An oil supply source is connected to the oil supply hole 10 via an oil supply pipe 11 .

The orbiting scroll 6 includes a disk-shaped end plate 4, a wrap 5 that stands upright on the end plate 4, and is formed in the same shape as the fixed scroll 3 wrap 2, and is provided on the opposite surface of the end plate 4 (hereinafter referred to as the back surface). Scroll boss 12 The center of the scroll boss 12 is located on the 0 m line of the center of the orbiting scroll 6.

The fixed scroll 3 and the orbiting scroll 6 have wraps 2,
5 facing each other, and the winding end 2a of the wrap 2 and the winding end 5a of the wrap 5 are
Point 0 (center O5 of fixed scroll 3 and orbiting scroll 6
(the midpoint on the line connecting the center Om).

The frame 14 is fixed to the outermost periphery of the sliding surface IA of the fixed scroll 3 with several bolts, and has a cover portion 14A in the center of the side facing the fixed scroll 3. The cavity part 14A is a plumber 6 having a pressure reducing valve 15 in the middle.
It is connected to the high pressure port 8 by.

The crankshaft 17 is rotatably supported by bearings 18 and 19 attached to the frame 14, and its axis coincides with the center Os of the fixed scroll 3. This crankshaft 17 is provided with a crank pin 17a at its end, and the center of this crank pin 17a is separated from the axis of the crankshaft 17 by a distance equivalent to O5·Om (generally called a turning radius). It is located in a place. This crank pin 17a is fitted into the scroll boss 12, and the crank pin 17a and the scroll boss 12
A bearing 20 is provided between the two.

Balancing weight 21 is attached to crankshaft 17.

As shown in FIG. 3, the Oldham ring 7 has a groove 7a on one surface and a groove 7b orthogonal to the groove 7a on the other surface. It is located between the back of the An Oldham key 22 fixed to the frame 14 is fitted into the groove 7a of the Oldham ring 7, and an Oldham key (not shown) fixed to the back surface of the orbiting scroll 6 is fitted into the groove 7b.

The mechanical seal 23 is housed in a housing 24 fixed to the frame 14, and includes a seal ring 25 fixed to the housing 24, a float ring 26 movably fitted into the crankshaft 17, and a seal ring 25 fixed to the housing 24. It consists of a spring 27 that presses the housing 24 and the seal ring 25 against the seal ring 25, and a ring 28 that maintains airtightness between the housing 24, the seal ring 25, and the crankshaft 17 and the float ring 26.

Next, the operation of this embodiment will be explained.

The compression operation and the operation during power generation will be omitted, and the effect of reducing sliding wear will be explained. Oil flows from the oil supply hole 10 into the annular groove 13 via the oil supply pipe 11, and the annular groove 13 is filled.

On the other hand, the orbiting scroll 6 is rotated by the crankshaft 17 (in the case of a compressor) or the high pressure port 8
It is caused to rotate by the working gas flowing into it. At that time, the orbiting scroll 6 is rotated on the sliding surface I of the fixed scroll 3.
As a result, a wedge effect, that is, a dynamic pressure effect occurs in the groove 13, and the oil film pressure in the annular groove 13 becomes higher than the supply pressure. and orbiting scroll 6
is raised very slightly from the sliding surface IA, and there is no metal contact between both scrolls. This greatly reduces sliding friction losses.

FIGS. 4(a) and 4(b) show a second embodiment of the present invention. In this embodiment, the inner and outer peripheral parts of the annular groove 13 in the first embodiment are deepened, and an annular groove 13'A is provided in the end plate 1 of the fixed scroll 3, with this part used as an oil reservoir part 29, and the oil supply hole 10 is It opens into the oil reservoir portion 29. The oil reservoir portion 29 may be located on either the inner circumference or the outer circumference of the annular groove 13A.

FIG. 5 shows a third embodiment of the invention.

In this embodiment, the annular groove 13 is connected to the end plate 4 of the orbiting scroll 6.
It was established in

FIG. 6 shows a fourth embodiment of the invention. In this embodiment, a throttle 30 is provided in the middle of the oil supply hole 10.

Although not shown, the annular groove 13.13A is divided into several pockets by dividing the annular groove 13.13A at equal angular intervals, and the oil supply hole 10 is provided in the orbiting scroll 6. The oil supply passage connected to the crank pin 17a,
Providing it on the crankshaft 17 and assembling each embodiment as appropriate is one embodiment of the present invention.

FIG. 7 is a diagram showing the relationship between the dimensionless depth hoe of the groove and the dimensionless performance η of the compressor obtained from experimental results. The grooves in the device used in the experiment were ring-shaped and pocket-shaped. The dimensionless depth hoe and dimensionless performance η of the groove are expressed by the following equations.

h, o*=ho/Ds Re-rt/rt.

Here, hO is the depth of jII\13.1.3A Inn)D
s is the outer diameter (1n) of the orbiting scroll 6, η is i:113,
Compression performance η0 when 13A is generating a hydrodynamic pressure effect indicates the performance of the compressor when the groove 13.13A is formed deeply and no hydrodynamic effect is generated (function of a hydrostatic bearing).

From this Fig. 7, the groove depth hot is (1 to 15)XIO-
A performance improvement was seen in the range of 4, (5 to IQ)
It can be seen that the performance is improved by 10 to 12.13% in the range of -'. This is caused by the dynamic pressure effect caused by the oil in the groove 13.13A reducing the depth hO.

The reason why the dynamic pressure effect occurs by reducing the depth hO of the grooves 13.13A will be explained.

The oil film pressure Po1l is generally determined by the oil viscosity μ, the sliding speed, the oil film thickness ho (the same symbol is used because it is closely related to the depth ho of the groove 13.13A), and the drive by the mirror motor:
! ! Assuming that U can be considered to be almost constant at l+, and the atmospheric temperature of the head plates 1 and 4 is determined, the dynamic pressure effect of the oil film ΔP
dyo (oil film pressure Pa1l/oil supply pressure Po) is mainly determined by the parameters of the oil film thickness hO1 and the slope m. That is, ΔP d y o = ΔP d y o
(1/hos, 1/m). From this equation, it can be seen that the shallower the oil film thickness hO, that is, the depth of the groove 13°13A, and the smaller the slope m, the larger the dynamic pressure effect ΔPdyo becomes. As the sliding speed U increases, the compressor function η becomes 1.0 or more. The dimensionless depth hoe of the groove increases as the groove depth hoe becomes deeper, as shown by the dotted line in FIG. 7, and becomes as shown by the dotted line in the case of three times the speed as shown by the solid line. It is also determined by the outer diameter Ds of the mirror scroll 6.

FIG. 8 is a diagram showing the relationship between the dimensionless oil film pressure Po1l* in the groove and the dimensionless depth holl of the groove.

From this figure, the range where the dimensionless depth hoe is small (1°3
x 10-' ~ 13 x 10-'), the oil film pressure Pa
1ls is higher than the oil supply pressure Po, indicating that a dynamic pressure effect is occurring. Incidentally, as the sliding speed U increases, the dimensionless depth hot at which the dynamic pressure effect is obtained becomes the 8th
The hoe expands in the deep direction as shown by the dotted line in the figure, and the solid line 3
At double speed, it will look like the dotted line.

According to these embodiments, in addition to reducing the sliding friction loss brought about by the generation of hydrodynamic pressure effects, the overturning moment of the orbiting scroll, that is, the force applied to the orbiting scroll becomes unbalanced in the circumferential direction, and the orbiting scroll is caused to move toward the crankshaft. Tilt with respect to the axis can be reduced. This is effective in keeping the slope m small at high speeds, suppressing a decrease in the dynamic pressure effect, and reducing gas leakage. Furthermore, since the bottom of the groove does not need to be sloped, the groove can be easily formed.

〔Effect of the invention〕

As described above, according to the present invention, during the orbiting motion of the orbiting scroll, the orbiting scroll becomes in a floating state due to the dynamic pressure effect of the oil inside the groove, which is exerted in conjunction with the tilt of the orbiting scroll end plate. Sliding friction loss between the orbiting scroll and the stationary part can be reduced.

[Brief explanation of drawings]

FIGS. 1 to 3 are explanatory diagrams of the first embodiment of this invention,
FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, FIG. 3 is a front view of the rotation prevention member, and FIGS. 5 is a sectional view of essential parts showing a third embodiment of the present invention, FIG. 6 is a sectional view of essential parts showing a fourth embodiment of this invention, and FIG. 7 is a sectional view of essential parts showing a fourth embodiment of this invention. is a diagram showing the relationship between the dimensionless depth hoe and the dimensionless performance η㉟ of the compressor, and Fig. 8 shows the relationship between the dimensionless depth hot and the oil film pressure P in the groove.
It is a diagram showing the relationship with o1l. 3...Fixed scroll, 6...Orbiting scroll, 7
... Oldham ring, 10 ... Oil supply hole, 13.13
A... Groove, 14... Frame, 17... Crankshaft, 23... Mechanical seal, 29... Oil reservoir. 1 (2) 7b ;%a [211 (c 5th 4th 40th (b), f15 (2) 6th (2)

Claims (1)

[Claims] 1. The fixed scroll and the orbiting scroll have an end plate,
It has a spiral-shaped wrap that stands upright on this end plate,
Both scrolls have interlocking wraps,
In the case where the orbiting scroll orbits without apparently rotating relative to the fixed scroll, the sliding surface that receives the thrust force of the orbiting scroll has a groove, and the depth of this groove is the same as the orbiting movement of the orbiting scroll. A scroll type fluid machine characterized in that it is formed at a depth where a dynamic pressure effect occurs.