JPH04153589A - Scroll type compressor - Google Patents

Abstract

PURPOSE:To reduce the consumed power by the simple structure and suppress the leak to the min. by supporting a fixed scroll through elastic deformation and making the clearance at the addendum of each spiral body smaller at the center part than that at the outer peripheral part. CONSTITUTION:A fixed scroll 4 is supported through elastic deformation, and the high center shape where the center part of an end plate 40 projects to a movable scroll 5 is kept, and the addendum clearance is larger on the peripheral part and smaller at the center part. Accordingly, the center part of the fixed scroll 4 is prevented from being deflected by a high pressure, and even if the center part of a movable scroll 5 is slightly deflected by a fluid pressure, the addendum clearance at the center part is prevented from being deflected, by the convex shape of the fixed scroll 4, and the inside leak of the compressed fluid reduces. Further, even if the addendum clearance at the center part of the scroll is reduced, and the sliding resistance at the center part is increased, the increase of the consumed power is little, in comparison with the case where the whole addendum clearance is reduced, since the area of the center part is less than that of the outer peripheral part.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a scroll type compressor, and in particular,
This is an improvement to the fixed scroll support structure in order to properly balance the tooth tip clearance of the spiral body.

[Conventional technology]

One of the conventional examples of scroll type compressors is Japanese Patent Application Laid-Open No. 56156.
It is described in Publication No. 492. Not limited to this example, but generally in the past, the tips of the spiral bodies formed on fixed scrolls or movable scrolls are designed so that a certain clearance is formed between them and the end plate surfaces of the opposing scrolls when assembled. It is normal to support

As a special conventional example, Japanese Patent Application Laid-Open No. 1-59482 discloses that the depth of the groove on the tooth bottom surface of the movable scroll is gradually deepened toward the center in consideration of the deformation of the scroll. An invention is disclosed in which the clearance between the tooth tip of the scroll and the bottom surface of the scroll is maintained at an appropriate value.

[Problem to be solved by the invention]

In conventional scroll-type compressors, the tooth tip clearance of the spiral body of each scroll is constant in the stationary state, so in the operating state, the crescent-shaped fluid pocket formed between the two scrolls is separated from the outer periphery. When the fluid is compressed by moving to the center, the pressure of the fluid at the center becomes higher than that at the outer periphery. As a result, the end plate of the scroll is deflected in the axial direction at the center, resulting in a large tooth tip clearance. As a result, the amount of leakage of the high pressure fluid in the center becomes large. As a result, the efficiency of the compressor decreases, so if the tooth tip clearance is reduced across the board, the sliding resistance of the movable scroll will increase, resulting in increased horsepower consumption and wear of the scroll.

The invention described in Japanese Unexamined Patent Publication No. 1-159482 seems to have addressed this problem, but changing the groove depth on the bottom surface of the scroll in stages involves manufacturing difficulties. Not only that, but the tooth tip clearance becomes discontinuous, and there is a possibility that a large amount of fluid leaks may occur in the discontinuous portion.

An object of the present invention is to find a means to more easily and reliably solve this problem.

[Means to solve the problem]

As a means for solving the above problems, the present invention includes a cylinder housing having an inlet, a rear side housing disposed behind the cylinder housing and having an outlet, and a spiral body formed on an end plate. and a fixed scroll sandwiched between the cylinder housing and the rear side housing near the outer periphery of the end plate, and a spiral body formed on the end plate and meshing with the spiral body of the fixed scroll at a shifted angle. movable scroll,
a front side housing formed to cover an opening of the cylinder housing; a shaft rotatably supported by the front side housing; and a shaft eccentrically disposed at an end of the shaft to provide orbital motion to the movable scroll. It has a crank mechanism and a detent mechanism that allows only the revolution of the movable scroll member and prevents its rotation, and the fluid is formed between each spiral body of the movable scroll and the fixed scroll by the revolution interlocking of the movable scroll. The pocket can compress the fluid by moving toward the center of the spiral body while decreasing its volume, and the end plate of the fixed scroll can be turned toward the movable scroll to have a medium-height shape. Scroll type compression characterized in that the scroll type compression is configured such that the clearance between the tooth tips of each spiral body of the fixed scroll and the movable scroll is smaller at the center than at the outer periphery by being supported by elastic deformation. provide a machine.

[Function] In a scroll compressor, when one or more crescent-shaped fluid pockets formed between a pair of scrolls gradually move from the outer periphery to the center due to the revolution of the movable scroll, In order to cause a volume reduction, the fluid sucked into the cylinder housing from the suction port is trapped in a fluid pocket at the outer circumference of the scroll, compressed while moving to the center, and sent from the center to the discharge port. By this, a fluid compression effect is achieved.

The end plate of the fixed scroll has its outer periphery sandwiched and fastened by the cylinder housing and the side housing, so there is no deformation at the outer periphery, but the fluid is compressed and becomes high pressure at the center. tends to deform in the axial direction under the pressure of If deformation is allowed, the clearance between the tip of the scroll and the spiral body of the movable scroll will be large, and the pressure of the fluid at the center will be higher than that at the outer periphery. leakage becomes significant. This leakage occurs because the center of the end plate of the movable scroll is pressurized due to the general structure of a scroll compressor, in which the movable scroll is supported by a rotation prevention mechanism at the outer periphery but not at the center. When deformed by the pressure of the fluid, the tip clearance at the center of the two scrolls increases, and the layer becomes significant.

On the other hand, in the compressor of the present invention, the fixed scroll is supported in an elastically deformed state, and the central part of the end plate maintains a medium-height shape protruding toward the movable scroll. The tip clearance is large at the periphery and small at the center.

Therefore, the center of the fixed scroll is prevented from bending due to the high pressure of the fluid, and even if the center of the opposing movable scroll is slightly bent due to the fluid pressure, the mid-height shape of the fixed scroll prevents the tip of the teeth in the center from bending. Clearance is not significantly increased and end-leakage of compressed fluid is reduced.

Furthermore, even if the sliding resistance at the center increases by making the tip clearance at the center of the scroll smaller than that at the outer periphery, the area of the center is smaller than that at the outer periphery, so the overall Compared to reducing the tooth tip clearance, the increase in horsepower consumption is very small and does not cause any problems (the decrease in horsepower consumption due to the reduction in sliding resistance at the outer periphery more than compensates for this). Become something.

〔Example〕

In the first embodiment of the scroll type compressor according to the present invention shown in FIG. 6, a case serving as an outer shell is formed.

A front head 7 fastened to the front side housing 1 has a cylindrical boss, and a shaft 8 inserted therein is rotatably supported by a bearing 11. A seal mechanism 12 is incorporated around the shaft 8 in the cylindrical boss portion of the front head 7, forming an airtight space within the case. A magnetic clutch (not shown) is attached to the outer periphery of the boss portion, and the rotational force of the automobile engine is transmitted to the shaft 8 via the magnetic clutch. The front side housing 1 has a holding hole in the center, and a bearing 10 is installed in the holding hole to rotatably support the shaft 8.

The fixed scroll 4 has a spiral body formed on its end plate 40, and is fixed in the case by having a flange portion 44 on the outer periphery of the end plate 40 sandwiched between the cylinder housing 2 and the rear side housing 3. , are integrally fastened to the case by the aforementioned bolts 6. It is also fixed to the cylindrical support portion 31 of the rear side housing 3 with bolts (not shown). A low pressure chamber is formed by the front radiator 7, the front head casing, the housing 1, the cylinder housing 2, and the fixed scroll 4, and the rear side housing 3
A high pressure chamber is formed by the fixed scroll 4 and the high pressure chamber and the low pressure chamber are provided with a discharge port and a suction port (not shown) communicating with each other, respectively.

Furthermore, a movable scroll 5 is provided in the cylinder housing 2.
is rotatably supported with respect to the eccentric wheel 14, and a spiral body is also formed on its end plate 50. By shifting the angle with respect to the fixed scroll 4 and meshing the spiral bodies, these spiral bodies are rotated. arranged to form a crescent-shaped fluid pocket therebetween.

The movable scroll 5 is connected to a rotation prevention mechanism (rotation prevention/rotation support mechanism) 9 having steel balls, and is supported so as to be able to revolve in a state where rotation is restricted.

The movable scroll 5 is connected to the shaft 8 via an eccentric ring 14, and is thereby given orbital motion to compress refrigerant gas between the movable scroll 5 and the fixed scroll 4. Also, eccentric wheel 1
4 is attached with a balance weight that offsets the centrifugal force caused by the orbital movement of the movable scroll 5.

The radius R of the orbital motion is determined by the shapes of both scrolls 4 and 5, so the centers of both scrolls are separated by the radius R, and the center of movable scroll 5 rotates around the center of fixed scroll 4. It is arranged like this.

That is, as the shaft 8 rotates, the movable scroll 5 performs a revolution movement with a radius R via the eccentric wheel 14. As a result, the contact line formed between both scrolls moves toward the center along the spiral shape, and the crescent-shaped fluid pocket moves toward the center while decreasing its volume, thereby compressing the refrigerant. Further, a discharge boat is provided in the center of the fixed scroll 4 to discharge the refrigerant gas compressed as described above into the high pressure chamber.

Furthermore, a discharge valve (not shown) that prevents the discharged refrigerant gas from flowing back from the high pressure chamber to the fluid pocket of the spiral body, and a stopper (not shown) that regulates the lift amount of the discharge valve are also installed.

Next, a configuration in which the fixed scroll 4 has a medium-high shape will be described. The fixed scroll 4 has a flange portion 44 on the outer periphery.
, cylinder housing 2, rear side housing 3
and are fastened with bolts 6.

Further, the cylindrical support portion 43 provided on the end plate 40 on the side opposite to the teeth of the spiral body of the fixed scroll 4 is connected to the cylindrical support portion 31 on the bottom of the rear side housing 3.
They are fastened by bolts (not shown). Here, the height y of the cylindrical support portion 43 of the fixed scroll 4 is 100 degrees higher than the height difference X between the end surface 32 of the rear side housing 3 and the end surface of the cylindrical support portion 31 in this embodiment.

With the above configuration, when the fixed scroll 4 and the rear side housing 3 are tightened with the bolts 6, etc., the end plate 40 of the fixed scroll causes elastic deformation in the axial direction toward the movable scroll 5, and as a result, the assembly is not possible before. The tooth bottom surface 42 of the fixed scroll 4, which was flat, now has a medium-height shape. Its middle height (difference in height between the outer periphery and the center) is approximately 50
− becomes. In this state, other parts are assembled, for example, the tooth tip clearance at the center of the spiral body (teeth) (the tooth bottom surface 42 of the fixed scroll 4 and the tooth tip 5 of the spiral body of the movable scroll 5).
1 or the tooth bottom surface 5 of the movable scroll 5
2 and the tooth tip 41 of the spiral body of the fixed scroll 4)
When adjusted to 30μ, the tooth tip clearance at the outer periphery of the spiral body (teeth) is 30μ. w +50m = 80m.

As mentioned above, the scroll compressor of the illustrated embodiment receives rotational torque from the engine (not shown) to the shaft 8 via the belt, and receives rotational torque from the movable scroll 5 via the eccentric wheel 14.
transmits rotational torque to. The movable scroll 5 performs a revolution movement due to the action of the rotation prevention and rotation support mechanism 9,
The movable scroll 5 and the fixed scroll 4 compress the refrigerant while sliding. Therefore, leakage of compressed gas from the fluid pocket (compression chamber) formed between the fixed scroll 4 and the movable scroll 5 is prevented by the compressor. has a significant impact on the efficiency of

Therefore, if we try to reduce the leakage by reducing the tooth tip clearance between the fixed scroll 4 and the movable scroll 5, the resulting increase in sliding resistance will directly affect the increase in horsepower consumption. , causing a decrease in efficiency. Therefore, adjusting the tooth tip clearance between the fixed scroll 4 and the movable scroll 5 is an important issue for improving efficiency.

In this case, the compressed gas is at a high pressure near the centers of the fixed scroll 4 and the movable scroll 5, so even if the tooth tip clearance is the same, there will be more leakage than at the outer periphery.

In addition, since the sliding area of the outer periphery of the fixed scroll 4 and the movable scroll 5 is wider than that near the center, if the tooth tip clearance is insufficient, sliding resistance will increase, causing an increase in horsepower consumption. . Therefore, it is desirable that the tooth tip clearance be small near the center and large at the outer periphery.

Furthermore, while the compressor is in operation, high gas pressure acts near the centers of the fixed scroll 4 and the movable scroll 5, whereas the rotation prevention/rotation support mechanism 9 receives a thrust load at the outer periphery of the movable scroll. Therefore, the end plate 50 deforms in the axial direction near the center of the movable scroll 5 and becomes a middle gate, causing leakage near the center.

Therefore, in this embodiment, the cylindrical support portion 4 of the fixed scroll 4 is
The height y of 3 is the height difference X of the end face of the rear side housing 3
By making the fixed scroll 4 medium-high due to elastic deformation, even when the center of the movable scroll 5 is deformed by gas pressure during operation, the clearance of the tooth tips is small at the center and large at the outer periphery. This reduces internal leakage and reduces horsepower consumption.

In this way, it is possible to reduce the clearance between the tooth tips at the central portions of the fixed scroll 4 and the movable scroll 5, which are subject to high pressure, thereby improving the sealing performance at the central portions and reducing internal leakage. In addition, since the clearance of the tooth tip is relatively large in the outer peripheral part of the fixed scroll 4 where pressure is low and there is little leakage, the horsepower consumption due to sliding between the tooth tip 51 (41) and the tooth bottom surface 42 (52) can be reduced. You can also do it.

On the other hand, the thrust direction load of the movable scroll 5 is supported by the rotation prevention/thrust support mechanism 9 located on the outer periphery on the opposite side of the teeth, so if high pressure is applied to the center during operation, the movable scroll 5 deforms and the center However, when the fixed scroll 4 is at a medium height as described above, the clearance between the tooth tips at the center is kept small and the above-mentioned Such leaks can be prevented.

Next, the effect when the fixed scroll 4 is elastically deformed to a medium height will be explained based on experimental data. As mentioned above, if the distance between the cylindrical support part 43 of the fixed scroll 40 and the flange part 44 is y, and the height difference between the end surface 31a of the rear side housing 3 and the outer peripheral end surface 32 is X, the amount of elastic deformation is y.
−x.

Figure 2 shows the amount of elastic deformation (y-
The performance in x) was shown.

Test items ■ Q: Cooling capacity (kcal/hr/PS) ■ L: Horsepower consumption (ps) ■ Q/L: Cooling capacity per unit horsepower (kcal/hr/PS)
/ hr / P-5) ■ ηV Volumetric efficiency (%) From Figure 2, the cooling capacity Q is calculated as follows: the elastic deformation amount y-x is 50-
It is highest at , and decreases as y-x increases due to leakage of compressed gas.

On the other hand, the horsepower consumption decreases in the range of y-x from 0 to 100a because the sliding resistance of both scrolls decreases as y-x increases, and remains constant above )'X=100 pm. As a result, Q-/L, which is a measure of efficiency, is
y -x -100m Q/L-1240kca
It is the highest with a value of l/hr/PS, and y
This is 3% higher than when -x is 01. At this time, the medium height of the tooth tip of the fixed scroll 4 is actually measured to be approximately 50 tn.
It becomes a. Therefore, the efficiency showed the highest value)'X=
10 On is the appropriate value for medium height, and the medium height at that time is approximately 50 m.

FIG. 3 shows a second embodiment. In this embodiment, a plate 15 is arranged on the cylindrical support portion 43 of the fixed scroll 4, and on the opposite side of the plate 15 from the fixed scroll 4,
The tip of the adjustment screw 16 is in contact with it.

The adjustment screw 16 is screwed into a female threaded hole of the rear side housing 3 from the outside, and by rotating the adjustment screw 16, its position can be adjusted in the front-rear direction. When the adjusting screw 16 is screwed in, the plate 15 is pushed to the left in the figure, so that the center portion of the fixed scroll 4 is also pushed toward the movable scroll 5. Therefore, the fixed scroll 4 can be elastically deformed into a medium-high shape.

At this time, by adjusting the screwing amount of the adjusting screw 16, the height (elastic deformation amount) of the fixed scroll 4 can be freely adjusted to an appropriate value. Although the adjusting screw 16 pushes out the fixed scroll 4 through the plate 15, the fixed scroll 4 and the adjusting screw 16 may be brought into direct contact without intervening the plate 15.

Further, in the first embodiment, the rear side housing 3
Bolts that are tightened from the rear may be omitted if necessary. Further, the front head 7, the front side housing 1, and the cylinder housing 2 may be integrated in some cases.

〔Effect of the invention〕

In the present invention, the tooth clearance at the center of the scroll where the high pressure of compressed fluid is acting is smaller than that at the outer circumference, which causes the fixed scroll to elastically deform. Since this is achieved by supporting in a large state, it can be realized with an extremely simple structure, and is also advantageous in terms of transportation costs.

While the sealing performance at the center of the scroll, where leaks tend to occur, is improved, the tooth tip clearance is slightly larger at the outer periphery, but since the outer periphery is an area where the pressure of the pressurized corrugations is low, leakage does not occur. Moreover, since the tooth tip clearance is large at the outer periphery having a large area, there is an advantage that sliding resistance is reduced and horsepower consumption is reduced.

In addition, even if the movable scroll is deformed mainly at the center due to the high pressure of the fluid, the fixed scroll is elastically deformed and supported so that it has a middle height toward the movable scroll, so there is no tooth tip clearance at the center. leakage is kept to a minimum.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a scroll compressor showing one embodiment of the present invention, Fig. 2 is a diagram showing the amount of elastic deformation of a fixed scroll and changes in performance, and Fig. 3 is a scroll showing another embodiment. It is a sectional view of a mold compressor. l...Front side housing, 2...Cylinder housing, 3...Rear side housing, 31...Cylindrical support portion, 31a...End surface, 32
... end face, 4 ... fixed scroll,
40... End plate, 41... Tooth tip of spiral body, 42... Tooth bottom surface, 43... Cylindrical support portion, 5... Movable scroll, 50... End plate, 51
... Tooth tip of spiral body, 52 ... Tooth bottom surface, 6 ...
Holt, 7...Front head, 8...
- Shaft, 9... Rotation prevention and rotation support mechanism, 10, 11, 13-... Bearing, 12... Seal mechanism, 14... Eccentric ring, 44... Flange portion.

Claims (1)

[Claims] a cylinder housing having a suction port; a rear side housing disposed at the rear of the cylinder housing and having a discharge port; A fixed scroll sandwiched between the rear side housing and
a movable scroll having a spiral body formed on an end plate and meshing with the spiral body of the fixed scroll at a shifted angle; a front side housing formed to cover an opening of the cylinder housing; and a front side housing. a shaft rotatably supported by a housing; a crank mechanism that is eccentrically disposed at an end of the shaft and provides a revolving motion to the movable scroll; and a detent mechanism that allows only the revolution of the movable scroll member and prevents rotation. A fluid pocket formed between each spiral body of the movable scroll and the fixed scroll due to the orbital movement of the movable scroll moves toward the center of the spiral body while decreasing its volume, thereby compressing the fluid. In addition, by elastically deforming and supporting the end plate of the fixed scroll so that it has a medium-height shape toward the movable scroll, each spiral body of the fixed scroll and the movable scroll can be A scroll compressor characterized in that the clearance between the tooth tips is smaller at the center than at the outer periphery.