JPH021995B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thrust bearing for a scroll compressor.

Before entering into the description of the present invention, the principle of a scroll compressor will be described.

The basic elements of a scroll compressor are as shown in Figure 1, where 1 is a fixed scroll, 2 is an oscillating scroll, 3 is a discharge port, 4 is a compression chamber, and \0 is a fixed point on the fixed scroll. , \0' is a fixed point on the swinging scroll 2. The fixed scroll 1 and the swinging scroll 2 are composed of spirals having the same shape, and the shape is a combination of involutes, circular arcs, etc., as is conventionally known.

Next, the operation will be explained. 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, and performs rotational movement, that is, swinging, without changing its attitude with respect to space, and rotates at 0°, 90°, as shown in Fig. 1.
Move like 180°, 270°. Oscillating scroll 2
As the scroll oscillates, the volume of the crescent-shaped compression chamber 4 formed between the fixed scroll 1 and the oscillating scroll 2 gradually decreases, and the gas taken into the compression chamber 4 is compressed and discharged from the discharge port 3. It is discharged from. During this time, the distance from \0 to \0' in Figure 1 is kept constant, and if the interval between the spirals is a and the thickness is t, then \0\0'
=a/2-t. a corresponds to the pitch of the spiral.

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

Next, the configuration and operation of a specific embodiment of the scroll compressor will be explained.

FIG. 2 shows an example of a conventional scroll compressor. In the figure, reference numeral 1 denotes a fixed scroll, which is composed of a scroll side plate 1a having an involute shape, a bottom plate 1b supporting the scroll side plate 1a, a discharge port 3, and a suction port 5. 2 is an oscillating scroll, which includes scroll side plates 2a having the same shape as the fixed side and opposite winding direction;
It is composed of a bottom plate 2b and a boss 13 that support the scroll side plate 2a. 4 is a compression chamber formed by the fixed scroll side plate 1a, the bottom plate 1b, the swinging scroll side plate 2a, and the bottom plate 2b; 6 is a bearing support; 7 is a thrust bearing; 8 is a crankshaft having an eccentric hole 14; Reference numeral 9 represents a rotation prevention device for preventing rotation of the swinging scroll 2, and reference numeral 10 represents a balancer. The above are the main components. In the swinging scroll 2, the fixed scroll 1 and the scroll side plates 1a and 2a are fitted to face each other, and the boss portion 13 of the swinging scroll 2 is connected to the eccentric hole 14 of the crankshaft 8. The crankshaft 8 is fitted into the bearing support 6, and the bearing support 6 and the fixed scroll 1 are connected to each other.
are connected with bolts or the like (not shown). Also, at this time, the thrust bearing 7 formed on the bearing support 6
The bottom plate 2b of the oscillating scroll 2 is assembled so that the opposite surfaces of the scroll side plate 2a are in contact with each other. Further, a balancer 10 is fixed to the crankshaft 8 by being press-fitted or screwed.

Next, the operation will be described. Rotational torque transmitted from a drive unit (not shown) such as an electric motor rotates the crankshaft 8. Then, the oscillating scroll 2 starts to rotate via the boss portion 13 of the oscillating scroll 2, but since the rotation is prevented by the rotation prevention device 9, the fixed scroll 1 and the oscillating scroll 2 are rotated as shown in FIG. The working fluid is compressed using the same compression principle. Here, the oscillating scroll 2 performs an eccentric revolution movement, and its static and dynamic balance is performed by the balancer 10.

In the scroll compressor as described above, a thrust force is generated that attempts to open the fixed scroll 1 and the swinging scroll 2 in the axial direction while compressing the working fluid. Conventionally, this thrust force was received by supporting the oscillating scroll bottom plate 2b with a thrust bearing 7 formed on a bearing support 6, but as can be understood from the scroll compressor principle shown in FIG. The pressure increases as you move toward the center,
As shown in FIG. 5a, the oscillating scroll 2 is distorted and uneven contact occurs between the surface of the bottom plate 2b opposite to the surface on which the scroll side plate 2a is formed and the inner edge side of the thrust bearing 7. was. That is, the bearing support 6 is integrally molded with the thrust bearing 7, and its rigidity is higher than that of the bottom plate 2b. Therefore, when the pressure at the center of the scroll becomes greater than the pressure at the outer circumference of the scroll, the bottom plate 2b
This is because the outer circumferential portion is warped and deformed so as to be separated from the outer end of the thrust bearing 7 while the inner circumferential portion is pressed against the inner edge portion of the thrust bearing 7. As a result, abnormal wear or seizure occurs in the uneven contact portion, which may damage the compressor or increase mechanical loss.

The present invention has been made to eliminate the above-mentioned drawbacks.

An embodiment of the present invention is shown in FIG. 3 below.

In the figure, a thrust bearing 7 and a bearing support 6 that supports the outer peripheral side of the thrust bearing 7 are formed separately and fastened together with bolts 11. The coupling means may be pins, fitting, or any other means, and the thrust bearing 7 and the bearing support 6 may be formed integrally. However, so that the inner peripheral side of the concentric thrust bearing 7 can be slightly deformed, the thrust bearing 7
In the figure in which a gap 7a is provided between the bearing support 6 and the bearing support 6, a step is provided on the bearing support 6 side. In addition, the thrust bearing 7 is made smaller than the rigidity of the oscillating scroll 2 that slides in contact with the thrust bearing 7 so as to have substantially the same rigidity. FIG. 4 is a diagram of the thrust bearing 7 viewed from the sliding side, and reference numeral 15 denotes oil grooves for lubrication, which are provided radially in the figure.

In the case of the above configuration, a small gap 7a is provided between the thrust bearing 7 and the bearing support 6 so that the inner peripheral side of the thrust bearing 7 can be deformed by thrust force, so that the scroll compressor cannot be operated. Even if the bottom plate 2b of the oscillating scroll 2 is distorted due to the axial thrust force generated when the gas is compressed, as shown in FIG. Since it is distorted according to the deformation of 2b, uneven contact will not occur.

Figures 6a, b, c, and d show other embodiments of the present invention. FIG. 6 shows a cross section taken along the line A-A in FIG. 4, and FIG. However, this stepped portion is provided with an inclination so that when the thrust bearing 7 is deformed, concentrated stress is not applied locally. In FIG. 6b, a larger taper is provided compared to that in FIG. 6a to disperse stress. FIG. 6c shows an example in which a step is provided on the thrust bearing 7 side. In this case, the stepped portion is also rounded to prevent concentrated stress. FIG. 6d shows an example in which a stopper 12 is provided in the gap 7a between the thrust bearing 7 and the bearing support 6. In the figure, the screw-shaped stopper 12 is embedded in the bearing support 6, but it may also be concentric. , it is also possible to make it convex on the thrust bearing 7 side. This stopper 12 is used to adjust the minute gap 7a. In addition, in the present invention,
When the gas is compressed, the thrust bearing 7 is deformed in a convex manner toward the bearing support 6, but since this deformed portion is only a part (inner circumferential side) of the thrust bearing 7, it has a large effect on the performance of the compressor. It's not a thing.

As described above, since the minute gap 7a is provided between the thrust bearing 7 and the bearing support 6 on the inner circumferential side of the thrust bearing, the inner circumferential side of the thrust bearing 7 is moved in the gap 7a by the thrust force generated during gas compression. Becomes deformable. Therefore, if the pressure at the center of the scroll is greater than the pressure at the outer circumference of the scroll,
The thrust bearing 7 follows the deformation of the bottom plate 2b and undergoes convex deformation toward the bearing support 6 side, eliminating the sliding of the thrust bearing 7 against one side due to strain deformation of the oscillating scroll bottom plate 2b during gas compression. Increased loss and wear can be suppressed and seizure accidents can be prevented. Furthermore, in the past, the thickness of the rocking scroll bottom plate 2b was increased in order to suppress distortion deformation, but according to the present invention, it is possible to make it thinner, and the centrifugal force caused by the eccentric movement of the rocking scroll 2 can be reduced, and the radial Since the directional force can be reduced, the reliability of the journal bearing can be improved, and it is also possible to downsize the journal bearing. In addition, the radial direction force is
A moment is generated that tends to cause the oscillating scroll to collapse, and this moment is received by the thrust bearing 7, but as the centrifugal force decreases, this moment also decreases. Therefore, the load on the thrust bearing 7 is also reduced, improving reliability. Further, the thrust bearing 7 can also be made smaller.

Furthermore, the present invention is applicable not only to compressors such as refrigerant compressors and air compressors, but also to fluid pumps, turbine expanders, and the like.

[Brief explanation of drawings]

Figure 1 is a diagram of the operating principle of a scroll compressor, Figure 2
3 is a sectional view showing an embodiment of the present invention, FIG. 4 is a plan view of a thrust bearing according to the present invention, and FIG. 5 is a sectional view showing a conventional scroll compressor. FIG. 6 is a cross-sectional view of a thrust bearing portion of another embodiment of the present invention. In the figure, 1 is a fixed scroll, 2 is an oscillating scroll, 1a is a fixed scroll side plate, 1b is a fixed bottom plate, 2a is an oscillating scroll side plate, 2b
is the swing side bottom plate, 3 is the discharge port, 4 is the compression chamber, 5 is the suction port, 6 is the bearing support, 7 is the thrust bearing, 7a is the gap, 8 is the crankshaft, 9 is the anti-rotation device, 10
is the balancer, 11 is the bolt, 12 is the stopper,
13 is a boss, 14 is an eccentric hole, and 15 is an oil groove.
In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Axial thrust force generated during gas compression in a scroll compressor that combines a fixed scroll and an oscillating scroll having a pair of spirals of the same shape and opposite winding directions, such as an involute. A scroll compressor characterized in that a gap is provided between a bearing that receives the bearing and a bearing support that supports the outer circumferential side of the bearing so that the inner circumferential side of the bearing can be slightly deformed by thrust force. 2. The scroll compressor according to claim 1, characterized in that the stiffness of the thrust bearing is approximately equal to or smaller than the stiffness of the swing-side spiral member.