JPH02301688A - Scroll type compression machine - Google Patents

Abstract

PURPOSE:To slide both scroll members smoothly and stably by rotatably inserting a drive pin which is provided at one end of a main shaft so that the eccentric distance from a main shaft center of the drive pin can be bigger than both of the eccentric distance from a bush center and the radius in circular orbit movement of an eccentric hole. CONSTITUTION:When a movable scroll member 31 is given fluid compression due to circular orbit movement, corresponding reactive force operates on a scroll element 311, or a member 31, in a contact direction of the circular orbit. This force operates on the center OC of a bush 5a, like FD. As the bush 5a is allowed for free rotation on a drive pin 5b, it is subjected to moment for rotation around the center OD of the pin 5b due to force FO. That is, the member 31 which is supported on the bush 5a is subjected to moment for rotation around the center OD of the pin 5b so that the scroll element 311 is pressed against a scroll element 301. Pressing force at the line-contact portion of both scroll elements 311, 301 is thus automatically gained to ensure the seal of a fluid pocket.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scroll compressor, and particularly relates to an improvement in a portion that transmits rotational motion of a main shaft to a movable scroll member as a circular orbital motion.

[Prior Art] As this type of hermetic scroll compressor, there is one shown in FIG. 7, for example. This container is composed of a casing 1 and a cup-shaped member 7.

Inside this container, a sleeve 2 is inserted via bearings 22 and 23.
1, a compression mechanism 3 disposed on one side of the housing 2, that is, inside the cup-shaped member 7, and a compression mechanism 3 disposed on the other side of the housing 2, that is, inside the casing 1. drive device 4 and sleeve 2 of housing 2
1, a main shaft 5 rotatably supported by the drive device 4 and one end connected to the drive device 4, an intake port 6 for introducing refrigerant gas containing lubricating oil into the compression mechanism 3, and a refrigerant compressed outside the cup-shaped member 7. and a discharge boat 8 for delivering gas.

The compression mechanism 3 includes a fixed scroll member 30 having a first spiral body 301 on one surface of a first plate body 300, and a second scroll member 30.
A movable scroll member 31 is provided with a second spiral body 311 on one surface of a plate body 310. The fixed scroll member 30 and the movable scroll member 31 are arranged such that the first spiral body 301 faces the second plate body 310 and the second spiral body 311 faces the first plate body 300. are combined to form a fluid pocket between them.

The drive device 4 is an electric motor, and has a main shaft 5 as its rotating shaft.
Through the action of the anti-rotation mechanism 9 provided on the other surface of the second plate body 310 and the nozzle housing 2, the movable scroll member 31 is caused to perform a circular orbit (orbital) motion to move the fluid pocket. It has become. An annular portion 300e is provided on the outer periphery of the first plate 300 so as to be in sliding contact with the outer periphery of one surface of the second plate 310 at the same height as the spiral body.

The main shaft 5 is fixed to the rotor 4a of the drive device 4. A bushing 5a is eccentrically provided at one end of the main shaft 5, and a counterweight 13 is also provided to offset the centrifugal force generated by the circular orbit movement of the movable scroll member 31. The bushing 5a is fitted into a boss 310a provided on the other surface of the second plate 310 via a bearing 53. □Both end faces of counterweight 13 and boss 310a
and the inner end of the housing 2, respectively.
, a second thrust bearing 51,52 is interposed. The thrust bearing may be a thrust sliding bearing, a thrust needle roller bearing, a thrust cylindrical roller bearing, or the like. Annular portion 300e of first plate 300 and cup-shaped member 7
A sealing member 72 is provided between the refrigerant gas and the refrigerant gas suction side and the discharge side. Furthermore, a spacer 74 is interposed at the joint between the annular portion 300e provided on the outer circumference of the first plate 300 and the cylindrical wall 24 of the nozzing 2.

In such a mechanism, when the drive device 4 operates, the movable scroll member 31 moves in a circular orbit.

Refrigerant gas enters the casing 1 from the suction boat 6, passes through the space between the housing 2 and the compression mechanism 3, and then enters the through hole 300C provided in the annular portion 300e of the first plate.
and into the fluid pocket between the two scroll members. The circular orbital motion moves the fluid pocket towards the center of both spirals 301 and 311. During this movement, the refrigerant gas is compressed. The compressed refrigerant gas is discharged from a discharge port 300 a formed in the first plate 300 into a discharge chamber 73 formed between the cup-shaped member 7 and the first plate 300 . The refrigerant gas discharged into the discharge chamber 73 flows out through a discharge port 8 provided in the cup-shaped member 7 to an external refrigeration circuit (not shown).

In this organization, 1. The second thrust bearing 51°52 is
The screw moment applied to the movable scroll member 31, the refrigerant gas compression force, as well as the contact sliding portion between the annular portion 300e provided on the outer periphery of the first plate 300 and the outer periphery of one surface of the second plate 310. be accepted mechanically. Furthermore, the axial position of the movable scroll member 31 is kept constant, thereby making the movable scroll member 31 and the fixed scroll member 3
This prevents the formation of a gap between the refrigerant gas and the refrigerant gas and prevents blow piping of high-pressure refrigerant gas.

[Problems to be Solved by the Invention] In this type of scroll compressor, the movable scroll member 31 moves in a circular orbit (orbiting) relative to the fixed scroll member 30 due to the rotation of the main shaft 5. During this movement, the following occurs. There is a problem.

In a scroll compressor, a fluid pocket is defined between the line contacts of two interdigitated spirals. Due to the relative circular orbital movement of the scroll members, the line contact portion moves toward the center along the surface of the spiral, and the fluid pocket moves toward the center while decreasing its volume, compressing the fluid. , it is necessary to ensure sufficient sealing force at the line contact area. On the other hand, if the contact force is increased to ensure sealing force, wear will occur on the surface of the spiral wound body. For this reason, the contact force of both spirals needs to be chosen to provide a suitable sealing force.

However, due to dimensional errors in manufacturing the spiral wound body, this contact force cannot always be kept constant when driven with a fixed crank radius, and manufacturing becomes difficult if the dimensional errors are to be reduced.

The theoretical radius of circular orbital motion R6 is generally given by R6. In the movable scroll member 31, the spiral center of the spiral body 311 is aligned with the spiral body 30 of the fixed scroll member 30.
It is arranged at a distance Ro from the spiral center of No. 1. Since there is the above-mentioned difficulty, the radius R1 of the circular orbit motion of the movable scroll member 31 is set to R,<Ro
The first method is to set the bushing 5a eccentrically with respect to the main shaft 5, and the bushing 5a is set so that the radius R2 of the circular orbit motion of the movable scroll member 31 is R2>Ro.
There is a second method in which a is provided eccentrically with respect to the main shaft 5.

In the first method, there is no line contact between the two spirals that are engaged with each other, and the gap between the two spirals, which are set very narrowly, is sealed using lubricating oil. However, the sealing force provided by this lubricating oil can provide a certain degree of sealing force when the pressure difference between the two fluid pockets that sandwich this seal point is small, but as the pressure difference increases, the sealing force becomes less effective. , the amount of blow-by of refrigerant gas between fluid pockets increases, leading to a decrease in compression performance.

In addition, in order to ensure the sealing force of the lubricating oil, it is necessary to supply a large amount of lubricating oil between both spiral coils, and since this lubricating oil mixes with the refrigerant gas, some lubricating oil inevitably flows out to the external refrigeration circuit. As a result, the refrigeration capacity decreases.

In the second method, a line contact portion is formed between the two spirals that are engaged with each other, but the contact force is large, and as the spirals wear out, the driving force also increases. Therefore, wear particles particularly cause a reduction in the life of the bearing, and an increase in driving force causes deterioration in performance, and an excessive load on the bearing causes a reduction in the life of the bearing.

Therefore, an object of the present invention is to provide a scroll compressor in which a fixed scroll member and a movable scroll member are in smooth and stable sliding contact.

[Means for Solving the Problems] A scroll compressor according to the present invention has an annular boss formed on the opposite surface of the plate of the movable scroll member to which the spiral body is fixed, and a bearing is provided in the annular boss. At the same time, a bushing provided at one end of the main shaft rotatably supported via the housing is rotatably inserted, and the bushing is provided with a bushing for canceling dynamic unbalance due to circular orbital motion of the bushing and the movable scroll member. The counterweight has a receiving surface for a thrust bearing on a surface facing the movable scroll member and a surface opposite thereto, and has a groove between the end surface of the annular boss and the inner end of the housing. 1. A scroll type in which a second thrust bearing (a thrust sliding bearing, a thrust needle roller bearing, a thrust cylindrical roller bearing, etc.) is interposed, and a spacer is interposed at the joint between the plate of the fixed scroll member and the housing. The bushing is a compressor, and the bushing has an eccentric hole, into which a drive pin provided at one end of the main shaft is rotatably inserted, and the eccentric distance of the drive pin from the center of the main shaft is ε1 is selected to be larger than both the eccentric distance ε2 of the eccentric hole from the center of the bushing and the radius R6 of the circular orbital motion, so that the center of the bushing is separated from the center of the main shaft by the radius of the circular orbit, The center of the drive pin is perpendicular to a line connecting the center of the bushing and the center of the main shaft, and is on the center side of the main shaft or on the opposite side from the center of the main shaft with respect to a line passing through the center of the bushing, and is also opposite to the center of the bushing. It is characterized in that it is located at a position offset in the rotational direction of the main shaft from a line connecting the centers of the main shaft, and further includes a support structure in the axial direction of the main shaft.

In addition, an engaging means is provided between the bush and the main shaft to limit the rotation angle range of the bush around the drive pin.

[Example] An example of the present invention will be described with reference to FIGS. 1 to 4. Components that are the same as those shown in FIG. 7 are given the same numbers and their explanations will be omitted. A drive pin 5b is provided on one end surface of the main shaft 5 at a position offset from the center so as to protrude in the axial direction. On the other hand, an annular boss 310a is formed on the plate body 310 of the movable scroll member 31 on a surface opposite to the spiral body 311. A thick disk-shaped or short shaft-shaped bush 5a is fitted into the boss 310a and is rotatably supported via a bearing 53. The main shaft 5 is supported in the axial direction by a thrust bearing 54 provided between a flange 5c integrated with the main shaft 5 and the inner end surface of the housing 2. The bush 5a has a disc-shaped counterweight 13 integrally extending in the radial direction. The bushing 5a also has an axial hole, an eccentric hole 56, located off-center, into which the drive pin 5b is inserted.

Figure 3 shows the center O5 of the main shaft 5 and the center QCs of the bushing 5a.
The positional relationship of the hole 56, that is, the center OD of the drive pin 5b is shown. In this state, the center is 0. The distance between and 06 is the circular orbit motion radius R8 mentioned above, and the eccentric distance ε of the drive pin 5b is
1 and the eccentric distance ε2 between the eccentric hole 56. When the drive pin 5b is inserted into the eccentric hole 56, the center 00 of both passes through QC.
0 on the opposite side of Os with respect to the line perpendicular to the line connecting c and O5. and 05 in the direction of rotation of the main shaft (in the direction of the arrow shown in FIG. 3).

In the structure of such a mechanism, the center O of the bushing 5a
c is centered on the center OD of the drive pin 5b and can move on an arc having a radius ε2.

That is, when the main shaft 5 rotates, the bush 5a is moved against the drive pin 5b.
A force acts to force the center Oc of the bushing 5a to move away from the spiral body 3 of the movable scroll member 31.
11 abuts against the side wall of the spiral body 301 of the fixed scroll member 30. Therefore, the center of the movable scroll member 31 is
It moves in a circular orbit around the main axis center 05 with a radius R8. Of course, at this time, since the movable scroll member 31 is prevented from rotating by the rotation prevention mechanism 9, it only moves in a circular orbit and does not rotate. On the other hand, the bushing 5a is
rotates at the same speed as the rotation of Movable scroll member 31
This circular orbital movement moves the fluid pocket and compresses the fluid.

Next, the advantages of using the bushing 5a having the eccentric hole 56 will be explained below.

When the fluid is compressed by the circular orbital motion of the movable scroll member 31, a reaction force thereof acts on the spiral body 311, that is, the movable scroll member 31 in the tangential direction of the circular orbit. This force eventually moves to the Bush center Oc in Figure 4.
It can be thought of as acting as shown in D. By the way, since the bush 5a is rotatable on the drive pin 5b, it receives the moment of rotation around the center 00 of the drive pin 5b by this force FD. This moment is calculated when the angle between the direction of the force FD and the line connecting the center Oc and 00 is θ, as shown in Figure 4.

It is expressed as FD·ε2s1nθ. As a result, the movable scroll member 31 supported on the bushing 5a receives a moment of rotation around the center OD of the drive pin 5b, which causes the spiral body 311 to rotate around the center OD of the drive pin 5b.
It will be pushed to 1. This pressing has a force of F,
If so.

Since F, eε2cosθ−FD*ε2sinθ,
It is given by FP-FD-1anθ.

That is, when the movable scroll member 31 is driven using the bushing 5a having the eccentric hole 56, a pressing force is automatically obtained at the line contact portion of both the spiral bodies 311 and 301 due to the reaction force of the fluid compression. This ensures the sealing of the fluid pocket. Furthermore, as mentioned above, the center OC of the bushing 5a is rotatable around the center OD of the drive bin 5b.
For example, even if the pitch of the spiral winding body or the wall thickness of the spiral winding body changes due to dimensional errors in the spiral winding bodies 301 and 311, 0c, 0c, etc. will change accordingly. You can change the distance. That is, O
As shown in Fig. 4, point c has a radius ε centered on OD.
It is possible to move on the arc of No. 2 to, for example, the point Oc' or Oc'. As a result, even if there is such a dimensional error, the movable scroll member 31 can move smoothly.

Spiral body 311 of movable scroll member 31 as described above
In order to obtain a pressing force F of
is not necessary. However, without this counterweight 13, the pressing force of the spiral body 311 against the spiral body 301 is actually due to the circular orbital motion of the movable scroll member 31, the bearing 53, and the bushing 5a with a radius R6 in addition to F. Since centrifugal force F is applied, the pressing force becomes large. As a result, the frictional force between the spirally wound bodies 311 and 301 increases, resulting in increased wear between them. Therefore, a counterweight 13 is provided so that its centrifugal force F2 cancels out the above-mentioned centrifugal force F1. As a result, spiral bodies 311 and 3
The movable scroll member 31 can smoothly move by obtaining an appropriate sealing force while reducing the wear of the movable scroll member 31.

As mentioned above, since the bushing 5a can rotate around the drive bin 5b, it has the advantage of having followability, but if the rotation angle of the bush 5a around the drive bin 5b is unlimited, there are disadvantages as well. be.

For example, if the rotation speed suddenly increases or decreases, the movable scroll member 31' and the bushing 5a will swing around the drive bin 5b due to their inertia, causing problems such as interference with surrounding parts. occurs. Therefore, it is preferable to limit the swing angle of the bush 5a and the movable scroll member 31 around the drive bin 5b. It is preferable to provide swing limiting means for this purpose.

FIG. 5 shows an embodiment of the swing limiting means.

Referring to FIG. 5, a projection 57 is provided at the center of the main shaft on the main shaft side of the counterweight 13 integrated with the bushing 5a, and a perforation 58 is provided in the main shaft 5 to receive the projection 57.
will be established. Since the perforation 58 is also located at the center of the main shaft, the bush 5a and, by extension, the movable scroll member 31 can rotate around the drive bin 5b by the clearance between the protrusion 57 and the perforation 58. Another method of supporting the main shaft 5 in the axial direction is shown in FIG. This is done with a snap ring 55 provided between the bush 5a and the drive pin 5b. That is, a snap ring 55 is provided on the outer periphery of the protruding portion of the drive bin 5b from the bush 5a so as to be engaged with the bush 5a.

In FIG. 5, the clearance between the protrusion 57 and the perforation 58 is determined according to the allowable swing angle range of the bushing 5a and the movable scroll member 31.

[Effects of the Invention] According to the present invention, the radial sealing between the movable scroll member and the fixed scroll member is performed smoothly, and the pressing force reduces wear on both scroll members, and an appropriate sealing force can be obtained. Since it can be set as follows, blow-pipe of compressed gas can be prevented, and a scroll type compressor with high efficiency and long life can be provided.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the first embodiment of the present invention, FIG. 2 is an exploded perspective view for explaining the relationship between the main shaft, bushing, and bearing shown in FIG. 1, and FIG. Figure 4 shows
FIG. 5 is a perspective view for explaining the main parts of the first embodiment of the present invention, and FIG. 6 is a diagram for explaining the force relationship of the parts shown in FIG. 7th longitudinal sectional view of the embodiment of
The figure is a longitudinal cross-sectional view of a conventional example. In the figure, 1 is a casing, 3 is a compression mechanism, 4 is a drive device,
5 is a main shaft, 5a is a boss, 5b is a drive pin, 6 is a suction boat, 7 is a cup-shaped member, 8 is a discharge port, 9 is an anti-rotation mechanism, 13 is a counterweight, 30 is a fixed scroll member, 31 is a movable scroll Element. Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] 1) A fixed scroll member having a spiral body fixed to one surface of a plate body and a movable scroll member having a spiral body fixed to one surface of the plate body are assembled so as to form a fluid pocket between them. In addition, an annular boss is formed on the other surface of the plate of the movable scroll member, a bearing is provided in the annular boss, and a bearing is provided at one end of the main shaft rotatably supported via the housing. A bush is rotatably inserted into the bush, and the bush is provided with a counterweight for offsetting dynamic unbalance due to circular orbital motion of the bush and the movable scroll member, and the counterweight has a surface on the movable scroll member side and a counterweight. The plate of the fixed scroll member has a receiving surface for a thrust bearing on the opposite surface, and first and second thrust bearings are interposed between the end surface of the annular boss and the inner end of the housing. A scroll compressor in which a spacer is interposed at the joint between the bushing and the housing, the bushing having an eccentric hole,
A drive pin provided at one end of the main shaft is rotatably inserted into the eccentric hole, and the eccentric distance ε_1 of the drive pin from the center of the main shaft is equal to the eccentric distance ε_2 of the eccentric hole from the center of the bush. and the radius of the circular orbital motion R_0, so that the center of the bushing is separated from the center of the main shaft by the radius of the circular orbital motion, and the center of the drive pin is separated from the center of the bushing and the main shaft. on the center side of the main shaft or on the opposite side from the center of the main shaft with respect to a line that is perpendicular to the line connecting the centers of the bush and passing through the center of the bush, and that is deviated from the line connecting the center of the bush and the center of the main shaft in the direction of rotation of the main shaft. 2. A scroll type compressor, wherein the bushing has a balance weight that offsets dynamic unbalance due to circular orbital motion of the movable scroll member and the bushing.