JPH0343476B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scroll fluid machine.

Before entering into the description of this invention, the principle of the scroll fluid machine will be briefly described.

Figure 1 shows the basic components and compression principle of a scroll compressor, which is one application of scroll fluid machinery. In Figure 1 a, b, c, and d, 1 is a fixed scroll, 2 is a swinging scroll In the moving scroll, 5 is a compression chamber formed by a gap between the fixed scroll 1 and the oscillating scroll 2, 6 is a suction chamber, and 8' is a discharge chamber formed at the innermost periphery. Further, 0 is the center of the fixed scroll 1. The fixed scroll 1 and the oscillating scroll 2 have spirals of the same shape and opposite winding directions, and the shape of these spirals is a combination of involutes or circular arcs, and a compression chamber 5 is formed between the spirals. It is formed.

Next, the operation will be explained. In FIG. 1, the fixed scroll 1 is stationary with respect to space, and the oscillating scroll 2 is combined with the fixed scroll 1 as shown in the figure, without changing its attitude with respect to space, that is, rotating on its axis. The fixed scroll 1 performs an oscillating motion of rotating around the center 0 of the fixed scroll 1, and moves as shown in the moving positions a, b, c, and d of FIG. 1. With this movement of the oscillating scroll 2, the compression chamber 5 gradually reduces its volume, and the gas taken into the compression chamber 5 from the suction chamber 6 is compressed at the discharge port 8' in the center of the fixed scroll 1. is discharged.

The outline of the device known as a scroll compressor is as above.

Next, the specific structure and operation of a conventional scroll compressor will be explained with reference to FIGS. 2 and 3.

FIG. 2 shows a specific embodiment in which a scroll compressor is applied to, for example, refrigeration, air conditioning, or an air compressor, and is configured as a compressor for a gas such as fluorocarbon. In FIG. 2, 1 is a fixed scroll, and 1a is a base plate of the fixed scroll 1, which also serves as a part of a shell to be described later. 2 is an oscillating scroll, 3 is a base plate of the oscillating scroll 2, 4 is an oscillating scroll shaft, 5 is a compression chamber, 6 is a suction chamber of the compression chamber 5, 7 is a suction hole, 8 is a discharge hole, and 8' is a A discharge chamber, 9 is a thrust bearing that supports the back surface of the base plate 3 of the swinging scroll 2, 10 is a bearing support fixed to the fixed scroll 1 with bolts, etc., and 11 is a shaft bearing that prevents the swinging scroll 1 from rotating and swings it. 12 is an Oldham chamber formed between the base plate 2 of the oscillating scroll 2 and the bearing support 10, and 13 is an Oldham joint formed in the bearing support 10 to connect the Oldham chamber 12 and the electric motor room, which will be described later. An oil hole, 14 is a crankshaft that drives the swinging scroll 2, 15 is an oil hole eccentrically drilled in the crankshaft 14, and 16 is provided eccentrically in the crankshaft 14 to fit with the swinging scroll shaft 4. A swing bearing, 17 is a main bearing that fits on the upper part of the crankshaft 14, 18 is a motor-side bearing that fits on the lower part of the crankshaft 14, 19 is a motor stator, 20 is a motor rotor, and 21 is a crankshaft on the upper part of the motor rotor 20. A first balancer fixed to 14, a second balancer 22 fixed to the lower end of the motor rotor 20, and 23
24 is a shell that fixes the fixed scroll 1, shaft support 10, motor stator 19, and motor side bearing 18 and seals the entire compressor; 24 is oil stored in an oil reservoir at the bottom of the shell 23; This is a motor room that houses the motor rotor 20 and the like.

The operation of the scroll compressor configured in this way will be explained. When the electric motor stator 19 is energized,
The electric motor rotor 20 generates torque and rotates together with the crankshaft 14. When the crankshaft 14 starts rotating, rotational force is transmitted to the swinging scroll shaft 4 fitted in a swinging bearing 16 provided eccentrically on the crankshaft 14, and the swinging scroll 2 is guided by the Oldham joint 11. The oscillatory movement is performed by the oscillating motion, and the above-mentioned compression action shown in FIGS. 1a, b, c, and d is performed.

The gas is sucked into the suction chamber 6 on the outer periphery of the rocking scroll 2 through the suction hole 7 and taken into the compression chamber 5.
As the crankshaft 14 rotates, it is sequentially fed inward and discharged from the discharge hole 8 provided in the center of the fixed scroll. Note that the oscillating motion of the oscillating scroll 2 accompanying the rotation of the crankshaft 14 tends to cause vibrations in the entire compressor due to unbalanced forces, but the first balancer 21 and the second balancer 22 statically and dynamically control the vibration of the oscillating scroll 2. Balance around the shaft 14 can be achieved, and the compressor can be operated without abnormal vibrations.

Moreover, FIG. 3 is a partial detailed view of FIG. 2. Figure 3a shows the oscillating scroll shaft 4 without gas compression.
is an axial cross-sectional view of a part of the oscillating scroll shaft 4, the crankshaft 14, and the spiral in a state where the oscillating scroll shaft 4, the crankshaft 14, and a part of the spiral are pressed in the direction of the oscillating bearing 16 only by the centrifugal force of the oscillating scroll 2, the base plate 3, etc.; Figure b is a partial cross-sectional view of Figure 3a. In these figures, 0 ₁
is the axis of the main bearing 17, ₀₂ is the axis of the crankshaft 14, ₀₃ is the axis of the swing bearing 16, ₀₄ is the axis of the swing scroll shaft 4, and FC is the center of the swing scroll 2 and the base plate. 3, etc., r is the amount of eccentricity of the rocking bearing 16 with respect to the crankshaft 14, _d1 is the bearing clearance of the rocking bearing 16, _d2 is the bearing clearance of the main bearing 17, and B is the amount of eccentricity between the spirals of the fixed scroll 1. The groove width, D is the actual swinging width of the swinging scroll 2, t is the thickness of the spiral of the swinging scroll 2, and C and _C1 are the radial directions formed between the spirals of the fixed scroll 1 and the swinging scroll 2. It is a gap, and generally C=C ₁ .

In the conventional scroll compressor as described above, the actual swing width D of the swing scroll 2 is as follows.

D = 2 (r + d ₁ /2 + d ₂ /2) + t = 2r + t + d ₁ + d ₂ ... 1 Therefore, the radial gap C between the spirals of fixed scroll 1 and oscillating scroll 2 is: C = (B-D) / 2={B-(2r+t+ _d1 + _d2 )}/2={(B-2r-t)-( _d1 + _d2 )}/2...2. In conventional scroll compressors, (B-2r-t) in the above two equations is set to be larger than (d ₁ + d ₂ ), and therefore, the fixed scroll 1
A radial gap C is always formed between the spirals of the orbiting scroll 2 and the scroll. Moreover, as shown in FIG. 4, in a normal operating state, in addition to the centrifugal force FC, a gas compression load Fg in a direction perpendicular to the centrifugal force FC acts on the oscillating scroll shaft 4, so that the resultant force F acts in the direction shown in FIG. 4, and the oscillating scroll shaft 4 is pressed in the direction of the resultant force F. Therefore, the radial gap C' between the spirals of the fixed scroll 1 and the orbiting scroll 2 in this state is even larger than the radial gap C when only the centrifugal force FC acts. Thus, if there is a radial gap C or C' between the spirals, contact between the spirals of the fixed scroll 1 and the oscillating scroll 2 cannot occur during operation of the scroll compressor, and therefore the side surfaces of the spirals are worn out. There is no problem in doing so, but
It is difficult to seal the radial gap of the compressor 5,
Through the above radial gap C or C', the compression chamber 5
Gas often leaked to the suction side.
When the gas inside the compression chamber 5 leaks to the downstream side, the amount of gas finally discharged from the discharge pipe 8 decreases, resulting in a decrease in volumetric efficiency, and the leaked gas has to be compressed again, reducing the input power of the motor. The disadvantage was that the coefficient of performance decreased.

Also, in order to eliminate the above-mentioned drawbacks, setting (d ₁ + d ₂ ) larger than (B-2r-t) in equation (2) above is an effective method for sealing the radial gap, but in practice Since there are variations in processing accuracy in the groove width B, eccentricity r, and plate thickness t of (B
The value of (B-2r-t) indicates the variation that is the sum of each variation, so at any crankshaft rotational position, (d ₁ + d ₂ ) is always smaller than (B-2r-t).
To increase , it is necessary to set the bearing clearances d ₁ and d ₂ sufficiently large. However, in general, the bearing clearance has an optimum value in order to sufficiently fulfill its original purpose of lubricating function, and if the bearing clearance is made larger than necessary, the lubricating function will be impaired. Therefore, it was necessary to make the processing accuracy of the groove width B, eccentricity r, and plate thickness t very high. Furthermore, if the center 0 of the fixed scroll 1 and the axis 0 ₁ of the main bearing 17 are misaligned for some reason, the gap C shown in FIG.
C ₁ will be equal, and in extreme cases, only one of them will become larger, and with the above gaps d ₁ and d _2, it is not possible to always make the gaps C and C ₁ zero.

Therefore, the accuracy of assembling the fixed scroll 1 with respect to the axis ₀₁ of the main bearing 17 must be set to be sufficiently high.

This invention was made in order to eliminate the above-mentioned drawbacks, and an eccentric ring having a swing bearing eccentric by a predetermined amount is fitted into an eccentric hole provided in the crankshaft 14, and the swing bearing and By fitting the swinging scroll shaft, the swinging scroll 2
The actual swing width D can be changed freely,
It is an object of the present invention to provide a scroll compressor in which leakage from the compression chamber is reduced by setting the actual radial clearance of the compression chamber 5 to 0, and the volumetric efficiency and coefficient of performance are improved as a result.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 5a and 5b and 6a and 6b.

5a and b, 16' is the crankshaft 14
26 is an eccentric ring made of a so-called bearing material fitted into the eccentric hole 16', and 16'' is a oscillator provided eccentrically from the center of the eccentric ring by a predetermined amount. dynamic bearing, 0
₄ is the eccentric bearing 16'' or the axis of the oscillating scroll shaft 4, ₀₅ is the eccentric ring 26 or the eccentric hole 1
6″ axis, e is the distance between 0 ₄ and 0 ₅ , R is 0 ₁ and 0 ₂
, that is, the amount of eccentricity of the oscillating scroll shaft. Since the other symbols are the same as those in FIG. 3, their explanation will be omitted. In addition, in FIGS. 5a and 5b, between the eccentric hole 16' and the eccentric ring 26, and between the swing bearing 1
A bearing gap exists between each bearing gap 6'' and the swinging scroll shaft 4. Since it is not particularly necessary, illustration thereof is omitted.

In the scroll compressor according to one embodiment of the present invention configured as described above, since the eccentric ring 26 can freely rotate around its axis ₀₅ ,
If some rotational force is applied, the axis 0 ₄ of the rocking bearing 16'' can rotate around the axis 0 _5. In other words, the eccentricity R can be freely changed. An easy-to-understand explanation will be given in Fig. 6b. Fig. 6a shows a state in which the spiral of the fixed scroll 1 is located relatively inside. As mentioned above, F is the resultant force of the centrifugal force F _c and the gas compression load F _g in,
This is a force that substantially acts on the rocking bearing 16''.
F' is the component force of the resultant force F in the direction perpendicular to the straight line 0 ₄ 0 ₅ , and this force tends to rotate the swing bearing 16'' around the eccentric ring axis 0 ₅ , and the swing radius R tends to increase.As a result, the spiral of the oscillating scroll 2 comes into contact with the spiral of the fixed scroll 1, and is balanced at the position shown in the figure.

Further, FIG. 6b shows a state in which the spiral of the fixed scroll 1 is located relatively outside. Even in this state, the force F' that rotates the oscillating bearing 16'' around the axis ₀₅ is still acting, so the volute of the oscillating scroll 2 contacts and is pressed against the vortex of the fixed scroll 1. In this way, regardless of the position of the volute of the fixed scroll 1, the volute of the oscillating scroll 2 always follows and presses against the vortex of the fixed scroll 1 during compressor operation, so that the radial seal of the compression chamber 5 is prevented. Therefore, the volumetric efficiency increases because the leakage of gas from the compression chamber 5 is reduced, and the increase in motor input due to recompressing the leaked gas is also reduced, so the coefficient of performance also decreases. Of course, there is a limit to the amount of change in the swing radius R, but it can be made large enough to cover variations in general machining and assembly, and therefore the groove width B , the machining accuracy of the eccentricity of the eccentric hole, the plate thickness t, etc. does not need to be high,
Furthermore, there is no need to increase the assembly accuracy of the fixed scroll 1.

Further, as described above, since the eccentric ring 26 is made of a bearing material, there is no need to use bearing metal or the like for the inner diameter of the eccentric hole 16' and the inner diameter of the swing bearing 16'', and the structure is extremely simple.

Also, as shown in FIG. 5b, the eccentric ring 26
By arranging the main bearing 17 at approximately the same position in the longitudinal direction of the crankshaft, the point of action of the load F that the swing bearing 16'' receives from the swing scroll shaft 4 and the main bearing 17 from the eccentric ring 26 are The points of application of the applied loads are located at the same position in the longitudinal direction of the crankshaft.This means that the main bearing load can be kept to a minimum, which is very desirable for increasing the reliability of the main bearing. It is.

As described above, the present invention provides the crankshaft 14
The eccentric rocking bearing 1 is inserted into the eccentric hole 16' provided in the
By fitting the eccentric ring 26 having a diameter of 6'' and fitting the oscillating scroll shaft 4 to the oscillating bearing 16'', the structure is simple and easy to process and assemble, while providing high efficiency and reliability. The effect of providing a scroll compressor can be obtained.

Although the embodiments of the present invention have been described with respect to a scroll compressor, it is clear that similar effects can be obtained even when the scroll compressor is used in a device such as an expander.

[Brief explanation of drawings]

Figures 1 a, b, c, and d are operating principle diagrams showing different operating positions of the scroll compressor, Figure 2 is a configuration diagram showing an embodiment of a conventional scroll compressor, and Figure 3 is Partially enlarged view, Figure 4 is the 3rd
A partially enlarged view of FIG. 2, FIG. 5, and FIG. 6 under different conditions from those shown in the figure are configuration diagrams showing one embodiment of the present invention. In the figure, 1 is a fixed scroll, 2 is an oscillating scroll, 5 is a compression chamber, 14 is a crankshaft, and 26
is an eccentric ring. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A fixed scroll and an oscillating scroll that have spirals of the same shape and opposite winding directions and that combine these spirals to form a compression chamber, and a side of the oscillating scroll opposite to the spirals. A crankshaft that supports an oscillating scroll shaft provided in the oscillating scroll shaft through an eccentric hole provided eccentrically by a predetermined amount and causes the oscillating scroll to perform an oscillating motion, and a bearing support that supports this crankshaft via a main bearing. and a rotation prevention mechanism that prevents the oscillating scroll from rotating around the oscillating scroll shaft and causes the oscillating scroll to oscillate around the main bearing. A scroll fluid machine characterized in that an eccentric ring having a swing bearing eccentric by a fixed amount is rotatably fitted, and the swing scroll shaft is rotatably fitted into the swing bearing. 2. The scroll fluid machine according to claim 1, wherein the eccentric ring is integrally formed with a bearing material. 3. The scroll fluid machine according to claim 1, wherein at least one of the main bearings supporting the crankshaft is disposed at approximately the same position as the eccentric ring in the longitudinal direction of the crankshaft. .