JPH03294681A - Scroll compressor - Google Patents

Abstract

PURPOSE:To maintain the friction coefficient of a radial bearing at a low value even in a high speed rotation area by providing recesses whose mean depth is 10 times or more of the radius clearance at the side surface center, on the reverse side of the load of an eccentric shaft and an eccentric bearing of a shaft. CONSTITUTION:A recess 5a is formed at the center of the right half of the larger shaft 5 of a shaft used in a scroll compressor. And a recess 6a is formed at the center of the right half inside a rotary bearing 6 in the same manner. The mean depth of the recesses 5a and 6a is made about 10 times or more of the radius clearance of the bearing 6. As a result, a loss by the viscosity resistance of the oil flowing in the clearance on the surface at the reverse side where almost no function is necessary as a bearing is reduced. Consequently, the friction coefficient of the radial bearing can be maintained at a low value even in a high speed rotation area.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a scroll compressor used in air conditioners and the like.

Conventional technology In recent years, compressors used in air conditioners such as room air conditioners have been required to be extremely quiet, as represented by low vibration and low noise, due to the need for a comfortable living environment. In addition to improving energy efficiency throughout the year, improvements have been made to achieve more comfortable temperature control functions and to realize a wide range of variable rotation.Within this social background, scroll compressors It is characterized by low vibration and low noise, and in the large capacity range of 3 to 5Kw, it is rapidly replacing the scroll type as it has a high efficiency of more than 10% compared to the conventional reciprocating type and rotary type. However, scroll type compressors generally suffer from compression leakage in the low speed range.
Efficiency tends to decrease. Furthermore, in the high-speed rotation range, efficiency tends to decrease due to increased loss in the bearing section. In response to these issues, improvements in the sealing technology between the blades and the accuracy of blade machining have greatly improved the efficiency degradation in the low speed range, but sufficient improvements have not been made in the high speed rotation range.

Problem to be Solved by the Invention One of the points for improving the efficiency of a scroll compressor in the high-speed rotation range is the radial bearing, especially the large shaft portion 5 at the upper part of the shaft 4 and the dynamic spring in the conventional structure shown in FIGS. 6 and 7. The aim is to reduce the loss of the pivot axis 9. The loss torque ΔTr is expressed as ΔTr-F-r-fJ F・Bearing load, r, shaft radius, fj: It is important to lower the friction coefficient fj without changing the radius r and load F. This is a challenge.

Means for Solving the Problems The present invention has a fixed spring having a spiral spring and a spring paired with the fixed spring, and receives a driving force from a shaft having an eccentric shaft or an eccentric bearing, and rotates while receiving a driving force. A scroll compressor comprising a dynamic spring that is prevented from rotating by a prevention mechanism and performs a rotating motion, and a bearing block that bears the shaft in a radial direction and is fastened to the fixed spring, and the eccentric shaft portion of the shaft. A scroll compressor is characterized in that a recess with an average depth h of 11≧1QxCC and a radius gap between the shaft and the bearing is provided in the center of the side surface on the opposite load side of the eccentric bearing portion of the shaft, and with this configuration, The above problem was solved.

Function: Compared with the conventional bearing configuration, the scroll compressor of the present invention has the same oil film distribution on the shaft on the load side as before, so the load capacity is the same, but the load capacity is the same on the non-load side. Compared to the conventional method, the resistance due to the viscosity of the fluid is reduced in the area where the recesses are formed, so the coefficient of friction is reduced accordingly. This tendency is particularly noticeable in high-speed rotating machines, and scroll compressors with high efficiency can be realized over a wide range of applications.

EXAMPLE An example of the present invention will be described below. FIG. 1 is a partial cross-sectional view showing the structure of a scroll compressor embodying elements of the present invention. Reference numerals 1 and 2 denote a stator and a rotor of a drive motor, respectively, and the stator 1 is press-fitted into the shell 3. The rotor 2 is shrink-fitted to the shaft 4 and transmits the driving force of the rotor 2 to the shaft 4. The shaft 4 has a thick shaft 5 at the top, and an eccentric bearing 6 that is eccentric to the axis of the shaft 4 in a position parallel to the thick shaft 5. A bearing block 7 bears the shaft 4.

Reference numeral 8 denotes a dynamic spring, which has a spiral spring 8a and a pivot shaft 9 inserted into the eccentric bearing 6. The fixed spring 10 has a spiral spring 10a paired with the dynamic spring 8.
and mesh to form a compression chamber.

A thrust ring 11 supports the axial load of the dynamic spring.

Reference numeral 12 denotes an Oldham ring of a rotation prevention mechanism that slides in a groove provided in the bearing block 7 and prevents the rotational movement of the dynamic spring 8. 13 is a Zydo brake 1 which is sandwiched between the fixed spring 10 and the bearing block 7 and fastened with bolts,
The gap in the height direction of the moving spring 8 is adjusted.

Refrigerant gas is sucked in through the suction pipe]4, enters the shell 3, and is then sucked into the compression chamber through the suction hole 15. When the shaft 4 rotates, the dynamic spring 8 performs a turning motion, and the constant spring 1
Since the volume of the space surrounded by 0 and the dynamic spring 8 gradually decreases, the refrigerant scum is discharged from the discharge chamber 1G by pushing up the discharge valve 17 and into the discharge muffler 18. Finally, it is discharged from the discharge pipe 19. The refrigerating machine oil 21 accumulated in the lower shell 20 flows upward through the oil cover 22 through the diagonal elongated hole 23 provided in the shirt l-4 due to centrifugal force, and reaches the upper part of the pivot shaft 9. After lubricating the thrust ring 11 large shaft 5,
The oil leaf 111 returns to the inside of the seal 1 through the hole 24.

FIG. 2 is a three-dimensional view showing details of the shaft 4 used in the scroll compressor of the present invention.

A four part 5a is formed in the center of the right half of the thick shaft 5 of the shaft 4. Similarly, a recess 6a is formed in the center of the inner right half of the swing bearing 6.

FIG. 3 shows the direction of the force applied to the thick shaft 5 and the oil film pressure distribution, which is the reaction force generated in the bearing.

In a scroll compressor, when the rotation direction of the thick shaft is clockwise, the load (F) due to compressed scum acts to the left (with respect to the eccentric direction) as shown in the figure. Even when the shaft 4- rotates, the direction of the load F always remains 90" to the left with respect to the eccentric direction and does not change. Conversely, the bearing on the bearing block side changes the load direction the same way during one rotation. do.

Conversely, the eccentric bearing 6 of the pivot shaft 9 always receives a load in the same direction. That is, the load side of the pivot shaft 9 changes.

Because of the load generation condition unique to scroll compressors, it is effective to provide a concave portion on the opposite load side of the present invention. That is, as shown in FIG. 3, in the thick shaft 5, oil film pressure is generated only on the surface on which the load F acts, and the surface on the opposite side to the load hardly needs to function as a bearing. Therefore, on the anti-load side, it is possible to devise ways to reduce the loss caused by the viscous resistance of the oil flowing in the gap between the shaft and the bearing, that is, to reduce the coefficient of friction. The recessed portion 5a of the present invention is one example thereof, and is formed into a crescent shape by eccentric processing in consideration of workability. I left both ends and only the center part,
This is to avoid deteriorating the ease of assembly.

As a result of experimental studies, it was determined that the average depth 11 of this recess is approximately 10 times or more the radial clearance C between the shaft and the bearing.

FIG. 4 is a diagram comparing the friction coefficients of the so-called partially circular arc shaft of the present invention and a conventional perfect circular bearing with an offset line groove. The horizontal axis is the Simmerfeld index S, which is a dimensionless number that indicates the degree of fluid lubrication of the bearing, and its definition is μ: viscosity coefficient of lubricating oil, N1 rotation speed, D, shaft diameter L: bearing length, 2C: Diameter clearance between shaft and bearing, F: Load load. From this experimental result, when 5=10-2, the friction coefficient fj of both is 10-3, but as the Simmerfeld number S increases, the difference increases, and when S=1, the structure of the present invention is better than the conventional one. It was demonstrated that the value is about 1/3.

FIG. 5 is a diagram comparing the efficiency of scroll compressors, and it can be seen that the scroll compressor of the present invention exhibits superior characteristics with less deterioration in efficiency than the conventional example even in a high speed rotation range.

In this embodiment, an example is shown in which an eccentric bearing 6 is provided on the shaft 4, but in a configuration in which an eccentric shaft is provided, a recess similar to the recess 5a of the thick shaft 5 described in the embodiment is installed in this eccentric shaft. Just do it.

Effects of the Invention The scroll compressor of the present invention, with the above-described configuration, can maintain the friction coefficient of the radial bearing portion at a low value even in the high-speed rotation range, so it is possible to achieve high compressor efficiency over a wide rotation speed range. I was able to make it happen.

[Brief explanation of the drawing]

Figure 1 is a partial sectional view showing the overall structure of the scroll compressor of the present invention, Figure 2 is a three-dimensional view showing details of the shaft in Figure 1, and Figure 3 is how the load is applied to the thick shaft and the oil film pressure generated. A conceptual diagram showing the distribution, Fig. 4 is a friction coefficient Simmerfeld number characteristic diagram of the present invention and the conventional one, Fig. 5 is a compressor efficiency characteristic diagram of the present invention and the conventional compressor, and Fig. 6 is a configuration diagram of a conventional scroll compressor. FIG. 7 is an exploded perspective view of the main part of FIG. 6. 4...Shaft, 5...Thick shaft, 5a,
6a... recess, 6... eccentric bearing, 9...
...Rotating axis.

Claims (1)

[Claims] A motion having a fixed spring having a spiral spring and a spring forming a pair with the fixed spring, which receives a driving force from a shaft having an eccentric shaft or an eccentric bearing, and is prevented from rotating by an anti-rotation mechanism and performs a turning motion. A scroll compressor comprising a spring and a bearing block that bears the shaft in the radial direction and is fastened to the constant spring, the center of the shaft and the eccentric shaft portion of the shaft or the opposite-load side side of the eccentric bearing portion of the shaft. average depth h
h≧1×CC: A scroll compressor characterized in that a concave portion is provided for a radial gap between the shaft and the bearing.