JPH0327722B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scroll fluid machine used as an air compressor, refrigerant compressor, or expander.

[Conventional technology]

The specific structure and operation of a conventional scroll fluid machine will be explained with reference to FIGS. 3 to 8.

FIG. 3 shows the principle of a scroll fluid machine, in which 1 is a fixed scroll, 2 is an oscillating scroll, 5 is a compression chamber consisting of 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, O is the center of the fixed scroll 1. The fixed scroll 1 and the oscillating scroll 2 are spirals of the same shape, combining involutes or circular arcs, and are offset by 180 degrees from each other to form a compression chamber. In this state, as shown in Fig. 3 a, b, c, and d, only the oscillating scroll is moved around the center O of the fixed scroll 1 while keeping its posture angularly constant, that is, without rotating. It performs an oscillating motion that rotates around the object. Accompanied by such rocking motion, the compression chamber 5 gradually reduces its volume, and the gas taken in from the suction chamber 6 is discharged from the discharge port 8' in the center of the fixed scroll 1.

Fig. 4 shows a conventional scroll compressor disclosed in Japanese Patent Application Laid-Open No. 59-103981, and shows a specific example of applying the scroll compressor to, for example, refrigeration, air conditioning, or an air compressor. It is configured as a compressor for gas such as chlorofluorocarbons. In FIG. 4, 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 Discharge chamber, 9
1 is a thrust bearing that supports the back surface of the base plate 3 of the oscillating scroll 2, 10 is a bearing support fixed to the fixed scroll 1 with bolts, etc., and 11 is the oscillating scroll 1.
12 is an Oldham's chamber formed between the base plate 2 of the oscillating scroll 2 and the bearing support 10; 13 is an Oldham's chamber 12 formed in the bearing support 10; 14 is a crankshaft that drives the oscillating scroll 2, 15 is an oil hole eccentrically drilled in the crankshaft 14, and 16 is an oil return hole eccentrically provided in the crankshaft 14. An oscillating bearing that fits into the oscillating scroll shaft 4; 17 a main bearing that radially supports the large diameter portion of the upper part of the crankshaft 14; 18 a motor-side bearing that mates with the lower part of the crankshaft 14; 1;
9 is a motor stator, 20 is a motor rotor, 21
22 is a second balancer fixed to the lower end of the motor rotor 20; 23 is the fixed scroll 1, the shaft support 10, the motor stator 19, and the motor side bearing; A shell 18 is fixed to seal the entire compressor, 24 is oil stored in an oil reservoir at the bottom of the shell 23, and 25 is a motor chamber housing the motor stator 19, 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, the rotational force is transmitted to the oscillating scroll 4 fitted in the oscillating bearing 16 provided eccentrically on the crankshaft 14, and the oscillating scroll 2 is guided by the Oldham joint 11. Perform a rocking motion, Figure 3a,
The above-mentioned compression actions shown in b, c, and d are 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. 5 is a partial detailed view of FIG. 4. Figure 5a 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 10 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 5a. In these figures, O ₁
is the axis of the main bearing 17, _O2 is the axis of the crankshaft 14, _O3 is the axis of the swing bearing 16, _O4 is the axis of the swing scroll shaft 4, FC is 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 as follows: C = (B-D )/2 = {B-(2r+t+d ₁ +d ₂ )}/2 = {(B-2r-t)-(d ₁ +d ₂ )}/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. 6, under normal operating conditions, 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. acts in the direction shown in FIG. 6, 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 in the compression chamber 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 problem was that the growth factor increased and the product coefficient 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
-2r-t) indicates the variation obtained by adding up each variation, therefore, in order to always make (d ₁ + d ₂ ) larger than (B-2r-t) at any crankshaft rotational position, the bearing clearance must be It is necessary to set 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 O of the fixed scroll 1 and the axis _O1 of the main bearing 17 are misaligned for some reason, the gap C shown in FIG.
C ₁ will no longer be equal, and in extreme cases only one will become larger, and with the gaps d ₁ and d ₂ mentioned above, it will not be 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.

Furthermore, in order to eliminate the above-mentioned drawbacks, Japanese Patent Application Laid-open No. 59-162383 discloses a swing bearing that is eccentric by a predetermined amount in an eccentric hole provided in the crankshaft 14, as shown in FIGS. 7 and 8. By fitting the eccentric bushing and fitting the swing bearing and the swing scroll shaft, the actual swing width D of the swing scroll 2 can be freely changed, and the radial clearance of the compression chamber 5 can be set to zero. A means to do so is also shown. This means will be briefly explained below with reference to FIGS. 7a and 7b and 8a and 8b. FIG. 7 shows that an eccentric bush 26 is rotatably fitted into an eccentric hole 16' of a crankshaft 14, and an oscillating scroll shaft is attached to an oscillating bearing 16'' provided on the eccentric bush 26 with an eccentric amount e. 4 is rotatably inserted, and FIG. 7a is a sectional view seen from above;
Figure b is a sectional view seen from the side. FIG. 8 shows the operation of such means. FIG. 8a shows a case where the side plate of the fixed scroll 1 is located relatively toward the center due to variations in processing and assembly, the oscillating scroll 2 is also pushed toward the center, and the eccentric bushing 26 is moved to the left. The figure shows a state in which the oscillation radius R is becoming smaller. 8b shows a case where the side plate of the fixed scroll 1 is located relatively outward, and the oscillating scroll 2 rotates the eccentric bush 26 clockwise due to the force F acting on itself. , shown maintaining radial contact with the fixed scroll. By using an eccentric bush in this way, it is theoretically possible to always achieve radial sealing of the compression chamber. However, in reality, a force F is applied to the eccentric bush 26 from the oscillating scroll shaft 4.
Because of this, a frictional force (not shown) exists between the outer periphery of the eccentric bush 26 and the eccentric hole 16'.
Therefore, frictional resistance acts against the sliding of the outer periphery of the eccentric bushing, and acts in a direction to prevent rotation of the eccentric bushing. If the coefficient of friction between the outer periphery of the eccentric bush 26 and the eccentric hole 16' is
If it becomes large due to finishing accuracy, oil supply status, etc., the eccentric bushing will not rotate freely, and as a result, it will not be possible to achieve radial sealing of the compression chamber 5.
As mentioned above, there were problems even when using eccentric bushings.

Japanese Patent Publication No. 58-28433 shows a technique that can solve the above-mentioned problems with eccentric bushings.
Japanese Patent Publication No. 58-28433 is equipped with a crankshaft having an eccentric mounting plate, a swinging link that is locked to a pivot pin set up on this mounting plate, and a bushing provided at one end of the swinging link that swings. A scroll compressor configured to accommodate a scroll is shown. In a scroll compressor configured in this way, the swing link is locked to a relatively small-diameter pivot pin, so the frictional resistance when the swing link swings is very small. The moving scroll is free to follow radially and contact the fixed scroll to achieve a radial seal. However, in such a scroll compressor, the crankshaft receives the load from the oscillating scroll via the oscillating link and pivot pin, while the bearing supporting the main shaft is placed at a position offset in the axial direction. become.
Therefore, the crankshaft is subjected to a large moment, and as a result, a large load is placed on the bearings, which may cause problems such as bearing seizure.

[Problem that the invention seeks to solve]

As described above, the conventional scroll compressor has the disadvantage that it is difficult to seal the radial gap in the compression chamber, resulting in a decrease in volumetric efficiency and a decrease in the bulking coefficient. Furthermore, in conventional scroll compressors that use eccentric bushings to provide radial sealing, it is difficult to obtain a stable seal due to friction on the outer circumference of the eccentric bushing.
Again, there were drawbacks such as a decrease in volumetric efficiency and a decrease in the growth coefficient.

SUMMARY OF THE INVENTION In view of the above drawbacks, it is an object of the present invention to provide a scroll compressor that achieves sealing of the radial gap in the compression chamber, has good volumetric efficiency and bulking coefficient, and is highly reliable.

[Means for solving problems]

In order to solve the above-mentioned drawbacks, this invention has a concentric cylindrical bush that is loosely fitted into an eccentric hole provided in the crankshaft with a predetermined gap, and an oscillating scroll shaft that can be freely rotated around the inner periphery of the bush. It was inserted into the .

[Effect]

Even if variations occur in the fixed scroll and oscillating scroll side plates due to processing or assembly, the bushes roll around in the gap on their outer periphery, and the oscillating scroll side plate follows and comes into contact with the fixed scroll side plate, thereby adjusting the radius of the compression chamber. A directional seal is achieved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1a and b, which correspond to FIGS. 7a and b, and FIGS. 2a and b, which correspond to FIGS. 8a and b.

In FIG. 1, 16' is an eccentric hole provided eccentrically by a predetermined amount on the crankshaft 14, 27 is a cylindrical bushing made of so-called bearing material that is fitted into the eccentric notch 16', and 16'' is the outer periphery of the bushing 27. d ₃ is the gap between the outer periphery of the bush 27 and the eccentric hole 16', 0 ₁
is the axis of the main shaft, 0 ₄ is the axis of the oscillating scroll shaft 4,
R is the distance between 0 ₁ and 0 ₄ , that is, the swing radius of the swing scroll shaft. Since other symbols are the same as those in FIG. 5 or FIG. 7, explanations will be omitted. Also the first
In Figures a, b and Figure 2 a, b, the main bearing 17
Although there are bearing gaps between the oscillating bearing 16'' and the crankshaft 14, and between the oscillating bearing 16'' and the oscillating scroll shaft 4, they are not shown because they are not particularly necessary.

In the scroll compressor of the embodiment of the present invention configured as described above, since the gap d ₃ exists on the outer periphery of the bush 27, the bush 27
can be moved within a gap of d ₃ . That is, the swing radius R can be freely changed within the range of _d3 . This will be explained clearly in FIGS. 2a and 2b. FIG. 2a shows a portion where the side plate of the fixed scroll 1 is located relatively toward the center due to variations in processing and assembly. F is the resultant force of the centrifugal force Fc and the gas compression load Fg as described above, and is a force that substantially acts on the swing bearing 16''.When the force F acts in such a direction, the bush 27 has a swing radius R. However, the bush 27 comes to rest at the position where the side plates of the oscillating scroll and fixed scroll contact each other.In this case, the contact point between the outer periphery of the bush 27 and the eccentric hole 16' is Indicated by M _1. Also, in Fig. 2b,
A portion of the fixed scroll 1 in which the side plate is located relatively outward is shown. Even in this situation,
The resultant force F causes the bush 27 to swing in a larger swing radius R, causing the side plate of the swinging scroll 2 to move closer to the fixed scroll 1.
Move it to the position where it touches the side plate of the In this case, the contact point between the outer periphery of the bush 27 and the eccentric hole 16' is
It becomes _M2 . In this way, the bush 27 has an eccentric hole 1.
6' from M ₁ to M ₂ and from M ₂ to M ₁
This movement may be performed by sliding movement between the outer circumferential surface of the bush 27 and the inner circumferential surface of the eccentric hole 16',
The bush 27 may be rolled on the inner peripheral surface. However, since rolling motion generally has much less resistance than sliding motion, the above-mentioned movement is usually achieved by rolling. Therefore, in the case of the bush of the present invention, there is no problem with the radial tracking function of the oscillating scroll due to the large frictional resistance on the outer circumferential surface of the eccentric bush as explained in the conventional example, and the rolling of the bush is prevented. Therefore, the side plates of the fixed scroll 1 and the swinging scroll 2 can always be in contact with each other.

In this way, regardless of the position of the side plate of the fixed scroll 1, the side plate of the oscillating scroll 2 always follows and is pressed against the side plate of the fixed scroll during compressor operation, so that the compression chamber 5 is reliably sealed in the radial direction. I can do it. 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 build-up coefficient is also greatly improved. Of course, there is a limit to the amount of change in the swing radius R, but it is sufficient to set the gap _d3 so as to cover general processing and assembly variations.

In addition, since the bush 27 and the main bearing 17 are arranged at almost the same position in the axial direction of the crankshaft, the force F received from the oscillating scroll shaft 4 does not impart a moment to the main shaft, and the main bearing reaction force is minimized. Therefore, a great effect can be obtained in terms of reliability.

〔Effect of the invention〕

As described above, a concentric cylindrical bushing is loosely fitted into an eccentric hole provided in the large diameter part of the upper part of the crankshaft with a predetermined gap, and an oscillating scroll shaft is rotatably attached to the inner periphery of this bushing. Since the scroll compressor is constructed in such a way that it can be fitted in, and the large diameter portion of the crankshaft is supported in the radial direction by the main bearing, it is possible to obtain the effect of providing a scroll compressor with high efficiency and high reliability.

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 if the compressor is a device such as an expander.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an embodiment of the present invention, FIG. 2 is a partial sectional view illustrating the effects of the invention, and FIG. 3 is a diagram showing the operating principle of a scroll compressor. FIG. 4 is a sectional view showing the overall structure of the scroll compressor. FIGS. 5 and 6 are partial sectional views showing the main points of a conventional compressor. FIG. 7 is a partial sectional view showing the main points of another conventional compressor, and FIG. 8 is a diagram showing its operation. In the figure, 1 is a fixed scroll, 2 is an oscillating scroll, 4 is an oscillating scroll shaft, 5 is a compression chamber, 14 is a crankshaft, 16' is an eccentric hole, 17 is a main bearing, and 27 is a bush. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A fixed scroll and an oscillating scroll, each formed by protruding a spiral side plate such as an involute on the base plate surface, and forming a compression chamber between the side plate and the base plate when combined with each other, and this oscillating scroll. An oscillating scroll shaft is provided to protrude on the opposite side of the spiral side plate, and an eccentric hole is provided in the large diameter portion of the upper part by a predetermined amount of eccentricity. a crankshaft that supports the oscillating scroll in the radial direction through the main bearing, a bearing support that supports the crankshaft through a main bearing, and a crankshaft that rotates about the oscillating scroll shaft; In a scroll fluid machine equipped with an anti-rotation mechanism that prevents rotation and causes rocking movement around the main bearing, a cylindrical bush having an inner periphery concentric with the outer periphery is provided with a predetermined gap in the eccentric hole of the crankshaft. The oscillating scroll shaft is rotatably fitted into the inner periphery of the bushing and also serves as the oscillating bearing, and the main bearing supports the large diameter portion of the crankshaft in the radial direction. Features a scroll fluid machine.