Patent Application
20060159580
The present invention relates to a scroll compressor used for a refrigerating apparatus, an air-conditioning apparatus or the like, and a method for machining a scroll wrap.
A scroll compressor mainly has a structure shown in
Scrolls 52 and 53 are made by metal mainly of iron or aluminum. After they are formed by a casting or the like, side faces of wraps 50 and 51 sliding to each other are finished by being cut by end mill 57 having 2 to 10 cutting blades. In this manner, a required performance is secured.
Methods for finishing an involute curve-shaped scroll wrap by an end mill are disclosed by Japanese Patent Unexamined Publication No. H04-284509, Japanese Patent Unexamined Publication No. H07-164231, and Japanese Patent Unexamined Publication No. 2000-205155, for example. According to these publications, the feed rate of the end mill is controlled depending on the curvature radius of the involute curve. Any of these methods secures the plane roughness of a machined face.
However, in the case of the cutting and finishing by the machining by end mill 57 of wraps 50 and 51 having the above conventional structure, the side walls of wraps 50 and 51 have an accuracy that depends not only on the machining accuracy of end mill 57 but also on a runout due to an error at which end mill 57 is attached, and on the machining conditions. Thus, it is difficult to secure and manage a favorable accuracy in a stable manner, causing a poor surface roughness. In order to prevent the leakage of compressed gas by reducing the clearance between the side faces while scrolls 52 and 53 are engaged to each other, it is necessary that the dimensional accuracies of the side faces are improved.
Furthermore, each of end plates 52A and 53A has a large surface roughness because they are cut by end mill 57 together with the side faces of wraps 50 and 51, thus causing a sharp tip end at each convex at the surface roughness. This causes a sliding loss and a leakage loss of compressed gas, causing the efficiency of the compressor to be insufficient and to deteriorate easily.
Furthermore, the machining by end mill 57 is generally performed with the number of rotations of 20,000 in order to suppress the abrasion of the blade edge. Thus, in order to secure the machining efficiency, the feed amount per one rotation needs to be increased. If the feed amount per one rotation is increased, uneven machining is caused in a regularly-repeated manner due to the existence of a part of end mill 57 having the cutting blade and a part having no cutting blade. This uneven machining is caused with a pitch inversely proportional to the number of the cutting blades. Furthermore, an error caused when end mill 57 is attached also causes a regularly-repeated runout, causing swells in the longitudinal direction of the side faces of wraps 50 and 51. These swells cause minor vibrations in scroll 53 while the compressor is being operated, thus increasing noise.
Furthermore, when corners of side faces of wraps 50 and 51 and corners of end plates 52A and 53A at the boundary have abrasion when being slid with the corner of the tip end of the outer circumference of end mill 57, the shapes of corners of side faces of wraps 50 and 51 and the shapes of corners of end plates 52A and 53A are changed. In consideration of this, the inner and outer corners of the upper end face of an upper wrap engaged with a lower wrap need to be chamfered in a large amount and thus a space provided therebetween is increased. This increases the leakage of compressed gas, deteriorating the efficiency of the scroll compressor.
The scroll compressor of the present invention has a stationary scroll and a slewing scroll in which scroll-like wraps raised from the respective end plates of the respective scrolls are engaged to each other to provide a compression space therebetween. Then, fluid is inhaled, compressed, and discharged by using the circular orbit motion of the slewing scroll to allow the compression space to move from the outer periphery leading to an inhale opening to the center part leading to a discharge opening while reducing the capacity. At least any of side faces sliding to each other of the respective wraps has a machining mark parallel to the end plate. This face is a face cutting-machined by a non-rotational tool. A side face of the wrap perpendicular to the end plate has a shape of non-rotation obtained by Hale machining.
Hereinafter, a scroll compressor and a method for machining the scroll wrap according to embodiments of the present invention will be described with reference to the drawings. Elements similar to those in a previous embodiment have the same reference marks as those in the previous embodiment, and details descriptions thereof are omitted.
First, a scroll compressor according to a first exemplary embodiment of the present invention will be described with reference to
Compressor 6 is stored in sealed container 7 together with motor 8 for driving scroll 2, thereby providing a maintenance-free compression apparatus for air-conditioning. Thus, fluid to be inhaled, compressed, and discharged is a cooling medium. However, the present invention is not limited to this and may have any structure so long as the structure is provided so that a stationary scroll and a slewing scroll having scroll-like wraps are engaged to each other to provide a compression space to use the circular orbit motion of the slewing scroll to inhale, compress, and discharge fluid. Fluid to be handled is also not limited.
The inner periphery of sealed container 7 is fixed with stator 8A of motor 8. Rotator 8B of motor 8 corresponding to this is fixed to crank shaft 16 for driving scroll 2 of compressor 6. Main bearing member 18 and sub bearing member 20, which are fixed to the inner periphery of sealed container 7, axially support crank shaft 16 in a rotatable manner. Since the present exemplary embodiment shows the horizontal placement type one, main bearing member 18 and sub bearing member 20 axially support crank shaft 16. However, in the case of the vertical placement type one for example, crank shaft 16 also may be supported by one support. The lower part of sealed container 7 is lubrication storage 17.
Scroll 1 is attached to main bearing member 18 by a bolt for example. Scroll 2 and main bearing member 18 have therebetween Oldham's coupling 19 for preventing scroll 2 from rotating on its axis and for causing only a slewing motion (i.e., circular orbit motion) thereof. At the back face of scroll 2, there is provided slewing shaft 25 for driving the rotation that is inserted to eccentric bearing 26 in journal shaft 16A provided at one end of shaft 16. In accordance with the rotation of journal shaft 16A when crank shaft 16 is rotated, scroll 2 has a circular orbit motion via eccentric bearing 26 and slewing shaft 25. In sub bearing member 20, an end part of crank shaft 16 has oil feeding mechanism 27 and oil-sucking tube 27A is immersed in lubrication storage 17.
On the other hand, crank shaft 16 includes therein oil-feeding path 28. Crank shaft 16 drives oil feeding mechanism 27 and oil-sucking tube 27A sucks lubrication oil in lubrication storage 17. Then, lubrication oil lubricates the respective sliding parts of compressor 6 via oil-feeding path 28 and is discharged into sealed container 7. Thereafter, lubrication oil is sent through the clearance between motor 8 and sealed container 7 to return to oil-sucking tube 27A. The cooling medium inhaled by compressor 6 from inhale tube 29 is compressed in compression space 3 and is sent via discharge opening 5 and discharge tube 30 provided in sealed container 7, thereby being discharged out of sealed container 7.
In compressor 6 of the present exemplary embodiment, at least one of side faces 1C and 2D of the respective wraps 1B and 2B sliding to each other and at least one of side faces 1D and 2C of the respective wraps 1B and 2B consist of cutting-machined faces by Hale machining. For example, side faces 1C and 1D of wrap 1B of scroll 1 are Hale-machined by non-rotational tool 9 or the like shown in
In this manner, at least one of side faces 1C and 2D of scroll-like wraps 1B and 2B sliding to each other and at least one of side faces 1D and 2C of scroll-like wraps 1B and 2B sliding to each other are finished by Hale machining. An example is shown in
Furthermore, a surface finished by Hale machining has a fine texture. Thus, if one of side faces 1C and 2D and one of side faces 1D and 2C are Hale-machined respectively, both wraps 1B and 2B do not have therebetween such a clearance all over the sliding area in the direction along which they are raised that may cause the leakage of compressed gas. As a result, the leakage of compressed gas as described above is prevented, improving the compression efficiency.
As described above, the side faces of wraps 1B and 2B that are Hale-machined have little or no swell at the periphery and the side faces of wraps 1B and 2B have a smooth surface. As a result, scroll 2 has a circular orbit motion without having a minute vibration during the operation. Thus, a scroll compressor can be obtained whose operation noise is lower than that of the conventional one. Furthermore, abrasion is also reduced.
As shown in
Therefore, the structure as described above is convenient when the maintenance free sealed type scroll compressor as shown in
An example of the method of Hale machining for scroll-like wraps 1B and 2B as described above is shown in
As shown in
This eliminates the time and adjustment required when a cutting machining process is divided to a plurality of steps. As a result, the machining accuracy is increased and the machining time is reduced, providing a low-cost scroll compressor.
When the machining as described above is performed, the machine-finishing by non-rotational tool 9 is performed such that non-rotational tool 9 does not move back and forth in the direction of tool center axis line 12. As a result, microscopic concavity and convexity as shown in
In many cases, machining marks 31 as described above are obtained by transferring the shape the blade of non-rotational tool 9 at its side face. Thus, machining mark 31 can be formed to have an arbitrary shape by shaping the blade of non-rotational tool 9 at the side face. In order to sufficiently realize the characteristics of Hale machining as described above, although any method for machining a substrate may be used, an amount of a finishing allowance for Hale machining is required that is not influenced by the condition of the substrate face. Furthermore, a determined finishing allowance is preferably machined by one Hale machining operation as described above.
Machining mark 31 as described above is also achieved by a cutting machining by non-rotational tool 9 other than Hale machining, for example, by a grind stone. Thus, the effect for reducing the swell in the longitudinal direction of wraps 1B and 2B depending on the status of machining mark 31 is achieved regardless of the difference of a machining method.
Spaces 34 are provided between inner and outer chamfered corner parts 33 at the tip end of wrap 2B in slewing scroll 2 and corner parts 1E of stationary scroll 1. Spaces 36 are also provided between corner parts 2E of slewing scroll 2 having no curved surfaces and inner and outer chamfer parts 35 at the tip end of wrap 1B in stationary scroll 1. By providing corner part 1E with a curved surface, space 34 is several times smaller than space 36. Thus, the leakage of compressed gas through space 34 is reduced, providing a scroll compressor having high compression efficiency. Although the case where the structure as described above is applied to stationary scroll 1 is provided in the present exemplary embodiment as a typical example, the structure also may be preferably applied to slewing scroll 2.
As a result, even when finishing allowance 70 in Hale machining by non-rotational tool 9 is reduced to about 0.01 mm, the remainder of previously-machined face 45 that is a substrate cutting-machined by end mill 44 can be eliminated. Thus, a component having a high quality is obtained. Wrap 1B in particular frequently has a complicated shape, for example, an involute shape. Due to this reason, if wrap 1B is once detached from chucking apparatus 41 prior to a finishing step, the center or angle is dislocated. In this case, if finishing allowance 70 is smaller than about 0.05 mm, previously-machined face 45 remains, causing a defective quality. As stationary scroll 1 is Hale-machined without being detached from chucking apparatus 41, finishing allowance 70 is uniform to stabilize the load to non-rotational tool 9, thus providing a steady machining accuracy. Finishing allowance 70 is also minute and thus the load to non-rotational tool 9 is small, thus providing a long service life to non-rotational tool 9. As a result, a scroll compressor having a high quality and a low cost is obtained. Although the case where the method as described above is applied to stationary scroll 1 is provided in the present exemplary embodiment as a typical example, the method also may be preferably applied to slewing scroll 2.
As shown in
The above effect also can be provided by the separate machinings by two exclusive non-rotational tools for machining wrap 1B and machining end plate 1A, respectively. Although the case where the method as described above is applied to stationary scroll 1 is provided in the present exemplary embodiment as a typical example, the method also may be preferably applied to slewing scroll 2.
According to the present invention, the side face of a wrap has no or small swells by Hale machining in the longitudinal direction. Furthermore, the surface by Hale machining has a minute texture. Thus, the leakage of compressed gas is prevented from being caused at side faces sliding to each other of the respective wraps of a stationary scroll and a slewing scroll, improving the compression efficiency. Furthermore, the swells in the periphery direction of the side face of the wrap are small and have a smooth texture. As a result, the slewing scroll has a circular orbit motion during the operation without having a minute vibration. This provides a quieter scroll compressor that has smaller operation noise than that of the conventional design. The machining by a non-rotational tool also eliminates the need for a spindle apparatus for rotating the tool. As a result, the cost for operating the machinery in a plant or for purchasing equipment can be reduced, thus lowering the cost for producing the scroll compressor.
It is noted that the respective characteristics of the present invention can be used separately or in various combinations in a possible range.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003189350 | Jul 2003 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP03/13635 | 10/24/2003 | WO | 12/27/2005 |
