JP2817386B2 - Scroll compressor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll-type compressor, and particularly to a fixed scroll supporting structure in order to optimize the clearance of the spiral tooth tip. It is a thing.

[Conventional technology]

One of the conventional scroll type compressors is disclosed in
No. 92. In general, not limited to this example, in general, the tip of the spiral body formed on the fixed scroll or the movable scroll is formed such that a certain clearance is formed between the tip of the scroll and the end plate surface of the other scroll when assembled. It is usual to support.

As a special conventional example, JP-A-1-59482 discloses that
In consideration of the deformation of the scroll, the groove depth of the bottom surface of the movable scroll is gradually increased toward the center, and the clearance between the tip of the spiral body and the bottom surface of the scroll in the operating state is an appropriate value. Is disclosed.

[Problems to be solved by the invention]

In a conventional general scroll compressor, the tip clearance of the scroll body of each scroll is constant in a stationary state, so that a crescent-shaped fluid pocket formed between two scrolls is formed from an outer peripheral portion in an operating state. When the fluid is compressed by moving to the center portion, the pressure of the fluid at the center portion becomes higher than that at the outer peripheral portion, so that the end plate of the scroll flexes axially at the center portion,
The tip clearance becomes large, and the leakage of the high pressure fluid at the center becomes large. For this reason, the efficiency of the compressor is reduced. Therefore, if the clearance is reduced entirely, the sliding resistance of the orbiting scroll will increase, the horsepower consumption will increase, and the scroll will wear.

Although the invention described in Japanese Patent Application Laid-Open No. 1-159482 seems to address such a problem, changing the depth of the groove on the bottom surface of the scroll stepwise involves manufacturing difficulties. Not only does the tooth clearance become discontinuous,
There may be places where fluid leakage is large at discontinuous portions.

An object of the present invention is to find a means for solving this problem more simply and reliably.

[Means for solving the problem]

Means for Solving the Problems The present invention comprises, as means for solving the above problems, a cylinder housing having an intake port, a rear side housing disposed behind the cylinder housing and having a discharge port, and a spiral body formed on an end plate. A fixed scroll is formed between the cylinder housing and the rear side housing in the vicinity of an outer peripheral portion of the end plate, and a spiral formed on the end plate and engaged with the spiral of the fixed scroll at an angle. A movable scroll, a front side housing formed so as to cover the opening of the cylinder housing, a shaft rotatably supported by the front side housing, and the movable eccentrically disposed at an end of the shaft. A crank mechanism for orbiting the scroll, and only the orbiting of the movable scroll member A fluid pocket formed between the scrolls of the movable scroll and the fixed scroll by the revolving motion of the movable scroll, the fluid pocket formed in the direction of the center of the scroll while reducing the volume. The fluid can be compressed by moving to the fixed scroll, and the end plate of the fixed scroll is elastically deformed and supported so as to have a middle-to-high shape toward the movable scroll. There is provided a scroll compressor wherein the clearance of the tooth tip of each spiral body of the orbiting scroll is configured to be smaller at a central portion than at an outer peripheral portion.

(Operation)

In a scroll compressor, one or more crescent-shaped fluid pockets formed between a pair of scroll scrolls decrease in volume as the orbit of the orbiting scroll gradually moves from the outer periphery to the center. The fluid sucked into the cylinder housing from the suction port is caught in the fluid pocket at the outer peripheral portion of the scroll, compressed during the transition to the center portion, and sent out from the center portion to the discharge port. , A fluid compressing action is achieved.

The end plate of the fixed scroll has its outer peripheral portion sandwiched and fastened by the cylinder housing and the rear side housing, so that no deformation occurs at the outer peripheral portion, but at the center portion, the fluid which has been compressed to have a high pressure due to being compressed. Attempts to deform in the axial direction under pressure. If deformation is permitted, the clearance between the scroll scroll and the tooth tip of the scroll becomes large, and the pressure of the fluid at the center is higher than that at the outer periphery. Leakage becomes remarkable. This leakage is caused by the fact that the central portion of the end plate of the movable scroll is pressurized in the general structure of a scroll compressor in which the movable scroll is supported on the outer peripheral portion by a detent mechanism, but the central portion is not supported. Deformation due to the pressure of the applied fluid becomes even more pronounced with increased tip clearance at the center of the two scrolls.

On the other hand, in the compressor of the present invention, the fixed scroll is supported in an elastically deformed state, and the center portion of the end plate holds a middle and high shape protruding toward the movable scroll. The clearance is large at the periphery and small at the center. Therefore, the center portion of the fixed scroll is prevented from bending due to the high pressure of the fluid, and even if the center portion of the movable scroll of the other party is slightly bent due to the fluid pressure, the tip of the center portion is formed by the middle-high shape of the fixed scroll. The clearance does not increase significantly and the internal leakage of the compressed fluid is reduced.

Also, by making the tip clearance at the center of the scroll smaller than that at the outer periphery, even if the sliding resistance at the center is increased, the area of the center is smaller than that of the outer periphery. The increase in horsepower consumption is small compared to the case where the tooth clearance is reduced, and there is no problem. The decrease in horsepower consumption due to the decrease in sliding resistance at the outer peripheral portion more than compensates for this. It will be.

〔Example〕

In the first embodiment of the scroll type compressor according to the present invention shown in FIG. 1, the front side housing 1, the cylinder housing 2, the rear side housing 3, and the outer peripheral flange portion 44 of the fixed scroll 4 have several through bolts. By being fastened by 6, a case serving as an outer shell is formed. The front head 7 fastened to the front side housing 1 has a cylindrical boss portion, and a shaft 8 inserted therein is rotatably supported by a bearing 11. A sealing mechanism 12 is incorporated around the shaft 8 in the cylindrical boss portion of the front head 7 to form an airtight space in the case. A magnet clutch (not shown) is mounted on the outer periphery of the boss portion, and the rotational force of the vehicle driving engine is transmitted to the shaft 8 via the magnet clutch. The front side housing 1 has a holding hole in the center, and a bearing 10 is mounted 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 sandwiching the flange portion 44 on the outer periphery of the end plate 40 by the cylinder housing 2 and the rear side housing 3. , Are integrally fastened to the case by the bolts 6 described above. Also, the rear side housing 3 is secured by bolts (not shown).
Is fixed also to the cylindrical support portion 31 of FIG. And
A low-pressure chamber is formed by the front head 7, the front side housing 1, the cylinder housing 2, and the fixed scroll 4, and a high-pressure chamber is formed by the rear side housing 3 and the fixed scroll 4, and communicates with the high-pressure chamber and the low-pressure chamber, respectively. A discharge port and a suction port (not shown) are provided.

Further, a movable scroll 5 is rotatably supported in the cylinder housing 2 with respect to the eccentric wheel 14, and a spiral body is also formed on an end plate 50 thereof.
The spiral bodies are arranged so as to form a crescent-shaped fluid pocket between the spiral bodies by engaging with each other at an angle with respect to the spiral bodies. The orbiting scroll 5 is connected to a detent mechanism (rotation prevention and rotation support mechanism) 9 having a steel ball, and is supported so as to be able to revolve with rotation restricted.

The orbiting scroll 5 is connected to the shaft 8 via the eccentric wheel 14, thereby being given a revolving motion to compress the refrigerant gas with the fixed scroll 4. Eccentric wheel 14
Is mounted with a balance weight for canceling the centrifugal force caused by the revolving motion of the orbiting scroll 5.

Since the radius R of the revolving motion is determined by the shapes of both scrolls 4 and 5, 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. Are arranged as follows.

That is, the rotation of the shaft 8 causes the orbiting scroll 5 to revolve around the radius R via the eccentric wheel 14. As a result, the contact line formed between the scrolls moves toward the center along the spiral shape, and the crescent-shaped fluid pocket moves toward the center while reducing the volume to compress the refrigerant. A discharge port for discharging the refrigerant gas compressed as described above to the high-pressure chamber is formed in the center of the fixed scroll 4. Further, a discharge valve (not shown) for preventing 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) for regulating the lift amount of the discharge valve are also provided.

Next, a configuration in which the fixed scroll 4 has a middle-high shape will be described. The fixed scroll 4 has an outer flange portion 44.
To the cylinder housing 2 and the rear side housing 3
And fastened by 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 fastened to the cylindrical support portion 31 at the bottom of the rear side housing 3 by a bolt (not shown). ing. Here, the height y of the cylindrical support portion 43 of the fixed scroll 4 is set to be 100 μm higher in this embodiment 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.

With the above configuration, when the fixed scroll 4 and the rear side housing 3 are tightened with the bolts 6 or the like, the end plate 40 of the fixed scroll undergoes elastic deformation in the axial direction toward the movable scroll 5, and as a result, before assembly, The tooth bottom surface 42 of the fixed scroll 4 which has been flat becomes a middle-high shape. The intermediate height (difference between the outer peripheral portion and the central portion) is about 50 μm. In this state, other parts are assembled, for example, the tip clearance (fixed scroll 4) at the center of the spiral body (teeth).
When the gap between the tooth bottom surface 42 of the movable scroll 5 and the tip 51 of the spiral body of the movable scroll 5 or the gap between the tooth bottom 52 of the movable scroll 5 and the tooth tip 41 of the spiral body of the fixed scroll 4) is adjusted to 30 μm, The tip clearance at the outer periphery of the spiral body (teeth) is 30 μm + 50 μm = 80 μm.

As described above, the scroll compressor of the illustrated embodiment is
A rotary torque is applied to the shaft 8 from an engine (not shown) via a belt, and the movable scroll 5
To transmit rotational torque to the motor. The orbiting scroll 5 revolves by the action of the rotation preventing and rotating support mechanism 9,
The movable scroll 5 and the fixed scroll 4 slide and compress the refrigerant. Therefore, leakage of the compressed gas from the fluid pocket (compression chamber) formed between the fixed scroll 4 and the movable scroll 5 greatly affects the efficiency of the compressor.

Therefore, if the tip clearance between the fixed scroll 4 and the movable scroll 5 is reduced to reduce the leakage, the resulting increase in sliding resistance directly affects the increase in horsepower consumption. It causes a decline.
Therefore, adjustment of the clearance between the fixed scroll 4 and the movable scroll 5 is an important issue for improving the efficiency.

In this case, the pressure of the compressed gas becomes high near the center of the fixed scroll 4 and the movable scroll 5, so that even with the same degree of tooth tip clearance, leakage is greater than in the outer peripheral portion. Further, since the outer peripheral portions of the fixed scroll 4 and the movable scroll 5 have a larger sliding area than the vicinity of the center, if the tooth clearance is insufficient, the sliding resistance increases, which causes an increase in horsepower consumption. . Therefore, it is desirable that the tip clearance be small near the center and large near the outer periphery.

Further, during operation of the compressor, a high gas pressure acts near the center of the fixed scroll 4 and the movable scroll 5, whereas the rotation preventing and rotating support mechanism 9 receives a thrust load on the outer peripheral portion of the movable scroll. As a result, the end plate 50 is deformed in the axial direction near the center of the orbiting scroll 5 and becomes concave, which causes leakage near the center.

Therefore, in this embodiment, the cylindrical support portion of the fixed scroll 4 is provided.
The height y of 43 is the height difference x of the end face of the rear side housing 3.
By setting the fixed scroll 4 to a middle height by elastic deformation, even when the center of the movable scroll 5 is deformed by gas pressure during operation, the clearance of the tooth tip is small at the center and large at the outer periphery. In addition, the internal leakage is reduced and the horsepower consumption is reduced.

In this manner, the clearance of the tooth tip can be reduced at the central portion of the fixed scroll 4 and the movable scroll 5 where the pressure is high, so that the sealing performance at the central portion is improved and the internal leakage can be reduced. In addition, since the clearance of the tooth tip is relatively large in the outer peripheral portion of the fixed scroll 4 with low pressure and little leakage, the tooth tip 51 (41) and the tooth bottom 42
Horsepower consumed by sliding with (52) can also be reduced. On the other hand, the movable scroll 5 applies a load in the thrust direction,
Because it is supported by the rotation prevention and thrust support mechanism 9 on the outer peripheral side opposite to the teeth, it deforms when high pressure acts on the central part during operation, and the clearance of the tooth tip in the central part increases and internal leakage occurs. However, in the state where the fixed scroll 4 has the middle height as described above, the clearance of the tooth tip at the central portion can be suppressed small, and the above-described leakage can be prevented.

Next, the effect when the fixed scroll 4 is elastically deformed to a middle height will be described based on experimental data. As aforementioned,
If the distance between the cylindrical support portion 43 of the fixed scroll 4 and the flange portion 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.

FIG. 2 shows the amount of elastic deformation (y) when the clearance between the highest point of the tip of the fixed scroll 4 (or the movable scroll 5) and the tip of the counterpart is adjusted to 50 μm.
-X).

Test item Q: Cooling capacity (kcal / hr / PS) L: Power consumption (PS) Q / L: Cooling capacity per unit power consumption (kcal / hr / PS) η _v : Volumetric efficiency (%) From Fig. 2 The cooling capacity Q is such that the elastic deformation amount yx is 50 μm.
It is highest at m and decreases due to compressed gas leakage as y-x increases. On the other hand, the consumed horsepower L decreases when yx is in the range of 0 to 100 μm because the sliding resistance of both scrolls decreases as yx increases.
It is constant when y−x = 100 μm or more. As a result, Q / L, which is a measure of efficiency, is obtained when yx = 100 μm.
It shows the value of Q / L = 1240 kcal / hr / PS, which is the highest, and is 3% higher than when y-x is 0 μm. At this time, the middle height of the fixed scroll 4 is approximately
It becomes 50 μm. Therefore, y-
When x = 100 μm, the appropriate value for the middle height is about 50 μm.

FIG. 3 shows a second embodiment. In this embodiment, the plate 15 is disposed on the cylindrical support portion 43 of the fixed scroll 4, and the tip of the adjusting screw 16 is in contact with the plate 15 on the side opposite to the fixed scroll 4. The adjusting screw 16 is screwed into the female screw hole of the rear side housing 3 from the outside. The position of the adjusting screw 16 can be adjusted in the front-rear direction by rotating the adjusting screw 16. When the adjusting screw 16 is screwed in, the plate 15 is pressed to the left in the drawing, so that the central portion of the fixed scroll 4 is also pressed to the movable scroll 5 side. Therefore, the fixed scroll 4 can be elastically deformed into a middle-high shape. At this time, if the screwing amount of the adjusting screw 16 is adjusted, the middle height (the amount of elastic deformation) of the fixed scroll 4 can be freely adjusted to an appropriate value.
The adjusting screw 16 pushes out the fixed scroll 4 via the plate 15, but without the plate 15,
The fixed scroll 4 and the adjusting screw 16 may be directly contacted.

Further, in the first embodiment, the bolts to be tightened from the rear of the rear side housing 3 may be omitted if unnecessary. In addition, the front head 7, the front side housing 1, and the cylinder housing 2 may be integrally formed in some cases.

〔The invention's effect〕

In the present invention, the tip clearance at the center of the scroll where the high pressure of the compressed fluid is acting is made smaller than that at the outer periphery, and this makes the fixed scroll elastically deformed. Since this is achieved by supporting, it can be realized by a very simple structure, which is also advantageous in terms of manufacturing cost.

While the sealability at the center of the scroll, which is likely to leak, is improved, the tip clearance is slightly larger at the outer periphery, but the outer periphery is a part where the pressure of the fluid to be pressurized is low, so the leakage is large. And the tooth clearance at the outer periphery with a large area is large,
There is an advantage that the sliding resistance is reduced and the horsepower consumption is reduced.

Also, even if the movable scroll is deformed mainly by the high pressure of the fluid at the center, the fixed scroll is elastically deformed and supported so as to have a middle height toward the movable scroll, so that the tooth tip clearance at the center is provided. Is not significantly increased and leakage is minimized.

[Brief description of the drawings]

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 a change in performance, and FIG. 3 is a scroll showing another embodiment. It is sectional drawing of a mold compressor. DESCRIPTION OF SYMBOLS 1 ... Front side housing, 2 ... Cylinder housing, 3 ... Rear side housing, 31 ... Cylindrical support part, 31a ... End face, 32 ... End face, 4 ... Fixed scroll, 40 ... End plate, 41 …… the tip of the spiral body, 42 …… the bottom face, 43 …… the cylindrical support part, 5 …… the movable scroll, 50 …… the end plate, 51 …… the tip of the spiral body, 52 …… the bottom face, 6 ... Bolt, 7 ... Front head, 8 ... Shaft, 9 ... Rotation prevention and rotation support mechanism, 10, 11, 13 ... Bearing, 12 ... Seal mechanism, 14 ... Eccentric ring, 44 ... Flange Department.

Claims (1)

(57) [Claims] 1. A cylinder housing having a suction port, a rear side housing disposed behind the cylinder housing and having a discharge port, and a spiral body formed on an end plate, the vicinity of an outer peripheral portion of the end plate being provided. A movable scroll having a fixed scroll sandwiched between the cylinder housing and the rear side housing; a movable scroll formed on an end plate and formed with a spiral body which meshes with the spiral body of the fixed scroll at an offset angle; and the cylinder housing. A front side housing formed so as to cover the opening of the shaft, a shaft rotatably supported by the front side housing, and a crank mechanism arranged eccentrically at an end of the shaft to provide a revolving motion to the movable scroll. Has a detent mechanism that allows only the revolution of the movable scroll member and prevents rotation. A fluid pocket formed between the scrolls of the movable scroll and the fixed scroll by the orbital motion of the movable scroll is moved toward the center of the scroll while reducing the volume, thereby compressing the fluid. And by elastically deforming and supporting the end plate of the fixed scroll toward the movable scroll so that the end plate has a middle-high shape, the tooth tip of each spiral body of the fixed scroll and the movable scroll is formed. A scroll compressor wherein a clearance is configured to be smaller at a central portion than at an outer peripheral portion.