JPH07332261A - Fixed scroll and machining method therefor - Google Patents

Abstract

PURPOSE:To provide an efficient and high-precise fixe scroll which is constituted to eliminate high-precise machining of a functionally unnecessary part and to provide a machining method thereof. CONSTITUTION:A machining method for a fixed scroll comprises a first process wherein a spiral lap 1d is finished in such a state to grasp a rough machining part, such as the outer surface 1f and the flange surface 1g of a fixed scroll 1; a second process wherein a grinding work is applied on the outer peripheral surface la, the end plate surface lb, and the addendum surface 1c of the fixed scroll in such a state to grasp the scroll by means of a chuck and the end plate surface 1b is formed in such a state to be recessed from the outer peripheral surface 1a and the addendum surface 1c and a polishing work is applied on the outer peripheral surface 1a, the end plate surface 1b, and the addendum surface 1c after the second process; and a third process wherein a polishing work is then finished in such a state that the grinding grain mark of the polishing work remains on the end plate surface 1b. In the polishing method, the outer peripheral surface 1a, the end plate surface 1b, and the addendum surface 1c are brought into contact with a rotating disc-form grinding wheel and a pressure and polishing are applied by a pressure plate 7 of universal coupling structure from a direction opposite to that of the end plate surface 1b as the fixed scroll 1 is rotated and oscillated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed scroll of a scroll compressor used in an air conditioner and the like, and particularly, to form a pump in combination with an orbiting scroll.
The present invention relates to a fixed scroll that has been subjected to precision polishing and a processing method thereof.

[0002]

2. Description of the Related Art A scroll compressor is disclosed, for example, in Japanese Patent Laid-Open No.
As described in JP-A-187388, a spiral wrap formed by bringing the end plate surfaces of the fixed scroll and the orbiting scroll into contact with each other and standing upright on each end plate surface,
The combination compression function is obtained at minute intervals. Here, the pump section (compression mechanism section) will be described with reference to FIGS. 6 and 7. FIG. 6 is a sectional view of a compression mechanism portion of a general scroll compressor, and FIG. 7 shows the fixed scroll of FIG.
(A) is sectional drawing, (b) is a perspective view.

In FIG. 6, 11 is a fixed scroll and 1
1a is an outer peripheral surface, 11b is a mirror plate surface, 11c is a tooth tip surface, 11
d is a scroll scroll wrap (hereinafter, simply referred to as a wrap), 11e is a bottom surface of the scroll groove, 11i is a suction port, and 11j is a discharge port. Outer peripheral surface 11a, end plate surface 11
b and the tooth crest 11c are on the same plane, and as shown in detail in FIG. 7, the oil groove 11 formed on the circumference of the plane.
The outer peripheral portion is the outer peripheral surface 11a at the boundary of l, the flat portion up to the scroll groove is the end plate surface 11b at the boundary of the oil groove 11l, and the addendum surface 11c is the addendum surface of the scroll wrap.

12 is an orbiting scroll, 12a is a mirror plate surface,
Reference numeral 12b is a spiral scroll wrap (hereinafter simply referred to as wrap), 12c is a bottom surface of the scroll groove, 12d is a tooth top surface, 12e is a bearing, and 12f is a key groove. Further, 13 is a frame fixed to the inner surface of the closed case 17, 13a is a bearing provided on the frame 13,
b is a key groove, 13c is a pedestal surface, 13d is a mounting surface, 14
Is an Oldham ring, and 14a is a protrusion. Furthermore, 1
5 is a crankshaft, 15a is an eccentric part of the crankshaft, 16 is a fixed scroll 11 and the frame 1.
3 is a bolt for fastening with 3, 3 is a closed case, and 18 is a suction pipe.

The structure of the compression mechanism will be described in more detail. The crankshaft 15 is inserted into the bearing portion 13a of the frame 13, and the eccentric portion 15a of the crankshaft is attached to the bearing 12e provided on the orbiting scroll 12. Has been inserted. A hollow disk-shaped Oldham ring forming an Oldham joint in a key groove 13b provided in the frame and a key groove 12f provided in the orbiting scroll.
The protrusion 14a of 14 is inserted, and is configured to convert the rotational motion given to the crankshaft 15 by a motor (not shown) fastened to the crankshaft 15 into the orbiting motion of the orbiting scroll. There is.

The fixed scroll 11 is an orbiting scroll 1.
2, the outer peripheral surface 11a thereof is brought into contact with the mounting surface 13d of the frame and fastened by the bolt 16. The fixed scroll 11 and the orbiting scroll 12 are in a state of forming a minute clearance of about 10 ± 5 μm between the side surfaces of the respective wraps 11d and 12b and between the tooth tip bottom surfaces. In addition, the end plate surface 1 of the turning scroll 12
2a is the end plate surface 11b of the fixed scroll and the frame 13
It is housed in the gap formed by the pedestal surface 13c with appropriate clearance.

In the scroll compressor having the above structure, the wrap 12b of the orbiting scroll 12 orbits along the lap 11d of the fixed scroll 11 with a minute gap by the rotation of the crankshaft 15. By such an operation, the fixed scroll 1 is passed through the suction pipe 18.
Gas is sucked into the suction port 11i provided in No. 1 and is sequentially compressed toward the center inside the pump. The compressed gas is discharged from the discharge port 11j of the fixed scroll 11 into the closed case 17.

Due to such a compressing operation, a force which separates from the fixed scroll acts on the orbiting scroll 12 due to an increase in pressure inside the pump. In the separated state, the expected compression function cannot be obtained. Therefore, in order to prevent separation, a gas having an appropriate pressure (hereinafter, referred to as an intermediate pressure) is guided to the back surface of the orbiting scroll 12 from a through hole (not shown) provided in the bottom surface 12c of the orbiting scroll 12, and the orbiting scroll 12 is rotated. A structure is adopted in which the end plate surface 12a of 12 is pressed against the end plate surface 11b of the fixed scroll 11.

The performance of the scroll compressor as described above is
It is influenced by gas leakage from the sliding parts of the fixed scroll 11 and the orbiting scroll 12 and the inflow of high-pressure gas into the hermetically sealed container from the contact part between the frame 13 and the fixed scroll 11. That is, the intermediate pressure gas flows in between the end plate surface 11b of the fixed scroll 11 and the end plate surface 12a of the orbiting scroll 12, or the gas from between the tooth top surface 11c of the fixed scroll 11 and the bottom surface 12c of the orbiting scroll 12 flows. Leakage or bottom 1 of fixed scroll 11
It depends on gas leakage between 1e and the tooth tip surface 12d of the orbiting scroll 12, or inflow of high-pressure gas from between the outer peripheral surface 11a of the fixed crawl 11 and the mounting surface 13d of the frame 13. This gas leakage or gas inflow greatly depends on the accuracy of each component.

From this, items required for the processing accuracy of the fixed scroll will be described with reference to FIG. The fixed scroll 11 has an outer peripheral surface 11a, a mirror plate surface 11b, and a tooth crest 11c whose surface roughness is as small as 1 μm Rz or less, and has a flatness of 2 μm or less as a shape tolerance. As the tolerance, the perpendicularity of the lap 11d with respect to the mirror plate surface 11b is small to 3 μm or less, and the parallelism of the bottom surface 11e with respect to the mirror plate surface is small to 5 μm or less, and the dimensional tolerances are the mirror plate surface 11b and the bottom surface 11e.
Small dimensional tolerance between them is required. The standard of each of these precisions of the fixed scroll 11 is the end plate surface 11b.

An example of a conventional method for processing the fixed scroll 11 in order to meet the above required accuracy will be described with reference to FIG. FIG. 8: is sectional drawing which showed an example of the conventional processing method of a fixed scroll step by step. In FIG.
19 is a magnet chuck, 20 is a surface grinding wheel, 21
Is an outer peripheral chuck, 22 is a backing plate, and 23 is an end mill.

FIGS. 8 (a) and 8 (b) show a step of providing a high precision reference surface necessary for final finishing on the top plate 11h of the fixed scroll 11. First, FIG. 8 (a)
As shown in FIG. 3, the top plate 11h in a rough-processed state is gripped by the magnet chuck 19 having good flatness, and the outer peripheral surface 11a, the end plate surface 11b, and the tooth top surface 11c are processed using the surface grinding wheel 20 to be flattened. After that, as shown in FIG. 8B, the outer peripheral surface 11a and the end plate surface 11 that have been ground are machined.
b and the tooth tip surface 11c as a reference, the magnetic chuck 19
Then, the top plate 11h is processed into a flat surface by using the surface grinding wheel 20 and the top plate 11h is used as a reference surface for the subsequent processing. The processing shown in FIG. 8A and FIG.
If you cannot get the accuracy you expect from the top 11h
8 (a) is returned to the processing shown in FIG. 8 (a) again.
The processing of (b) is repeated.

FIG. 8C shows the lap 11d and the bottom surface 1.
1e shows an end mill finishing step, in which a top plate 11h used as a working reference is brought into close contact with a backing plate 22, an outer peripheral surface 21f of a fixed scroll 11 is gripped by an outer peripheral chuck 21, and an end mill 23 holds a lap 11d and a bottom surface 11e.
To finish. Through the above steps, the perpendicularity of the top plate 11h and the lap 11d is finished well.

FIG. 8D shows the outer peripheral surface 11a and the end plate surface 11
The finishing grinding step of b and the tooth tip surface 11c is shown, and the top plate 11h used as the machining reference surface is held by the magnet chuck 19 and finish grinding is performed using the surface grinding wheel 20. End plate surface 1
The dimension between 1b and the bottom surface 11e is measured by interrupting the machining several times during the machining, and the surface grinding process is performed while confirming the remaining margin. By the above processing, the posture tolerance (squareness, parallelism) created between the end mill processing and the surface grinding processing is excellently finished on the basis of the top plate 11h, which is a highly accurate processing reference, and a flat surface with a small whetstone contact area Because of the grinding process, shape tolerance (flatness), dimensional tolerance and surface roughness are finished well.

However, in the conventional machining method as described above, it is necessary to first set a high-precision machining reference on the top plate 11h. However, in view of the function of the compressor, the precision of the top plate 11h is in the rough cutting state. Sufficient and highly accurate grinding finish is unnecessary. That is, FIG. 8 in the conventional processing method
FIGS. 8A and 8B show steps that are completely unnecessary for the function of the fixed scroll 11, and such a conventional processing method includes a high-precision finishing step that is necessary only for processing, and thus productivity is improved. The processing method was poor. Further, in order to form a surface having a surface roughness of 1 μmRz or less by surface grinding, a high level of skill is required and the method has poor productivity.

Another example of the conventional method of processing a fixed scroll, which emphasizes production efficiency, will be described with reference to FIG. FIG. 9: is sectional drawing which showed other examples of the conventional processing method of a fixed scroll step by step. In FIG. 9, 2
4 is an end grinding wheel, 25 is a lapping machine, 26 is loose abrasive grains,
27 is a nozzle.

FIG. 9 (a) shows a step of gripping the outer surface 11f of the fixed scroll 11 which has been rough processed by the outer peripheral chuck 21 and finishing the lap 11d by the end mill 23. Figure 9
FIG. 9B shows a step of grinding the outer peripheral surface 1a, the end plate surface 1b, and the tooth crest surface 1c by using the end surface grinding grindstone 24 in the chuck state of FIG. 9A. According to the above steps, the fixed scroll 11 that does not require high precision in terms of function is used.
The flange surface 11g and the top plate 11h can be rough-processed and can be processed by one chuck, so that the posture tolerance (squareness, parallelism) can be improved between the end mill processing and the end surface grinding processing.

However, in the end surface grinding process as shown in FIG. 9B, the cup-shaped end surface grinding wheel 24 rotating at high speed is used.
It is customary to abut the fixed scroll 11 while rotating it at a relatively low speed and make a cut to grind it, but the tooth top surface 11c has a spiral shape and contacts the end surface grinding wheel 24. The area of the tooth tip surface 11c is constantly changing,
The load on the grindstone is constantly changing. Therefore, FIG.
In the processing mode as shown in (b), although unevenness in the circumferential direction can be made excellent, the outer peripheral surface 11a,
Unevenness occurs between the end plate surface 11b and the tooth crest surface 11c, and it is difficult to reduce the unevenness in the radial direction. In addition, the top plate 11h having a relatively thin structure is deformed during processing by the force due to grinding and is restored after the processing, which makes it difficult to reduce the radial unevenness. Therefore, it is difficult to improve the flatness of the outer peripheral surface 11a, the end plate surface 11b, and the tooth crest surface 11c by the end surface grinding.

Further, since the end surface grinding has a large contact area with the grindstone, importance is attached to the sharpness of the grindstone. Therefore, the surface roughness is 1 μmRz.
It was difficult to form the following with good productivity. Therefore, in order to form the flat outer peripheral surface 11a having a small surface roughness, the end plate surface 11b, and the tooth crest 11c, which cannot be satisfied by the end surface grinding process of FIG. 9B, a step of finishing by the flat surface lapping process after the end surface grinding process. Is shown in FIG.
In (c), flat lapping is performed while supplying the loose abrasive grains 26 mixed in the working liquid from the nozzle 27 to the rotating disc-shaped lapping disk 25.

FIG. 9 (d) schematically shows an example of the state of the fixed scroll 11 obtained by the flat lapping process of FIG. 9 (c). In such flat lapping,
Although the flatness and surface roughness of the outer peripheral surface 11a, the end plate surface 11b, and the tooth crest surface 11c can be made good, the standard for maintaining good parallelism between the end surface 11b and the bottom surface 11e cannot be used due to the processing form. There is no other standard than the bottom surface 11e, and there is no standard for maintaining the posture tolerance obtained by the end surface grinding in the pre-processing. Therefore, it is difficult to maintain the parallelism between the bottom surface 11e and the outer peripheral surface 11a, the end plate surface 11b, and the tooth crest 11c, and the perpendicularity between the end surface 11b and the lap 11d stably and with high accuracy. .

Further, it is impossible to machine the dimensions of the bottom surface 11e and the mirror plate surface 11b continuously and automatically from the machining mode, and the fixed scroll 11 is taken out of the machine several times before the machining is completed. Had to inspect.
Therefore, even the method shown in FIG. 9 was not satisfactory in productivity.

[0022]

In the case of aiming at the processing of a fixed scroll with extremely high accuracy, conventionally, a high-precision processing reference plane is set on the top plate 11h of the fixed scroll 11 or the flange surface 11g, and this ceiling is set. It was necessary to finish the plate 11h or the flange surface 11g as a reference, and finally finish the outer peripheral surface 11a, the mirror plate surface 11b, and the tooth crest 11c by surface grinding. Therefore, the top plate 11h or the flange surface 11g which does not require high precision in terms of the compressor function is used.
In addition, it has been unavoidable to provide a reference surface that is required only for highly accurate processing. Further, in order to obtain a good surface roughness only by grinding, there is no choice but to rely on the machining specifications at the expense of the grinding efficiency, and the machining efficiency is reduced.

A first object of the present invention is to solve the above-mentioned first problem, and to omit the high-precision machining of a functionally unnecessary portion, and to process an efficient and high-precision fixed scroll. To provide a method.

Further, placing emphasis on production efficiency, without setting a machining reference on the top plate 11h or the flange surface 11g, the end mill processing and the end surface grinding processing are carried out by one chuck, and then the flat lapping processing is carried out. The posture tolerance (squareness, parallelism) obtained in step 1 deteriorates. Furthermore, in such flat lapping, the dimensions of the end plate surface 11b and the bottom surface 11e cannot be measured inside the machine during processing. Therefore, the fixed scroll 11 is taken out of the processing machine by the time the processing is completed, and the processing is performed while checking the dimensions. For this reason, it is necessary to eliminate products that are out of the accuracy tolerance by measuring parallelism after processing, and the productivity is not satisfactory.

A second object of the present invention is the second object as described above.
It is an object of the present invention to solve the above problem and to provide an efficient processing method which enables processing in a process by a combination of grinding and polishing and obtains good accuracy. Further, a third object of the present invention is to provide a highly accurate fixed scroll without providing a functionally unnecessary processing standard by the method for processing a fixed scroll in which the above first or second object is achieved. However, it contributes to reduction of power consumption and improvement of reliability of the compressor.

[0026]

In order to achieve the above first object, the structure of the method for processing a fixed scroll according to the present invention is the same as the method for processing a fixed scroll in which a spiral wrap stands upright from the end plate surface. The outer surface of the fixed scroll,
A first step of cutting and roughing the flange surface and the top plate surface and finishing the spiral wrap in a state in which the rough processed portion is gripped by a chuck, and the outer peripheral surface of the fixed scroll, the end plate surface and Grind the tooth tip surface,
A second step of forming the end plate surface by denting from the outer peripheral surface and the tooth crest surface, and polishing the outer surface, the end plate surface and the tooth crest surface after the second step, and grinding the end surface to the end surface. The third step is to finish the polishing process in a state where the abrasive grain streaks of the process remain.

In order to achieve the above second object,
The configuration of the processing method for a fixed scroll according to the present invention is a method for polishing the outer peripheral surface of a fixed scroll, a mirror plate surface and a tooth tip surface, and the outer peripheral surface of the fixed scroll, a mirror plate surface and a tooth tip is applied to a rotating disk-shaped grindstone. While abutting the surfaces, rotating and swinging the fixed scroll, pressure is applied to the fixed scroll from a direction opposite to the end plate surface via a pressure plate having a universal joint structure formed by using a sphere. In addition, it is designed to be polished.

Further, in order to achieve the above-mentioned third object, the structure of the fixed scroll according to the present invention is such that, in a fixed scroll in which a spiral wrap stands upright from the end plate surface, an outer surface of the fixed scroll which has been rough-cut, A shape in which the spiral wrap is cut and finished while holding the flange surface and the like, and then the outer peripheral surface, end plate surface and tooth tip surface of the fixed scroll are ground, and the tooth end surface projects from the end plate surface and outer peripheral surface. As a groove bottom depth dimension with respect to the end plate surface, the parallelism of the end plate surface and the groove bottom, a fixed scroll satisfying the attitude tolerance of the wrap perpendicularity to the end plate surface, further, in the end plate surface By the micro machining allowance in the range where the abrasive grain scratches of the grinding process remain, the flatness and surface roughness of the outer peripheral surface, the mirror plate surface, and the tooth crest surface are secured, and the mirror plate surface obtained by the grinding process is Standard and That is the groove bottom dimensions and orientation tolerances those formed by performing polishing which does not practically change.

[0029]

According to the present invention, since the rough processing portion is chucked, the lap end mill processing and the end surface grinding processing are performed, and thereafter the polishing processing that does not require the reference surface is performed,
It is functionally unnecessary for the fixed scroll, and there is no need to set a highly accurate standard required only for machining. According to the present invention, it is possible to efficiently combine the functions of the end surface grinding process and the polishing process, and to provide a fixed scroll having good dimensions and attitude tolerances, as well as shape tolerances and surface roughness with high efficiency. be able to. According to the present invention, the outer peripheral surface, the end plate surface, the tooth tip surface is flat and the surface roughness is small, and it is possible to supply a fixed scroll having a good size and attitude tolerance with respect to the end plate surface, and gas leakage of the pump part, A scroll compressor with a small gas inflow can be provided.

The technical operation of the present invention will be described in more detail below. The outer surface that has been subjected to rough cutting is chucked, and while being held by the chuck, end mill finishing of the lap and end surface grinding using a cup grindstone (first step) are performed. With the end surface grinding finished, the dimension between the mirror plate surface and the bottom surface with reference to the mirror plate surface,
The parallelism between the mirror plate surface and the bottom surface and the squareness between the mirror plate surface and the lap are finished well by one chuck processing.

It is ideal that the outer peripheral surface, the mirror plate surface and the tooth crest surface are flat as expected and the surface roughness is reduced by the above-mentioned end surface grinding, but this is difficult as described above. Therefore, by utilizing the deformation of the fixed scroll due to the grinding resistance and the grindstone contact angle, the end plate surface is intentionally ground so as to be recessed from the outer peripheral surface and the tooth tip surface (second step). The fixed scroll whose end face grinding has been completed,
With the outer peripheral surface, end plate surface and tooth tip surface in contact with a rotating disk-shaped grindstone with good flatness, released from the chuck,
A pressure plate with a universal joint structure using spheres is applied to the top plate side to apply uniform pressure while pressing the rough surface, and the fixed scroll is rotated and oscillated to perform polishing (third step). .

At the initial stage of polishing, a high pressure is locally applied to the tooth crest and the outer peripheral surface protruding from the end plate surface, the tooth crest and the outer peripheral surface are preferentially removed, and the outer peripheral surface, the end plate surface and the tooth surface are removed. The front surface gradually becomes a flat surface, the surface roughness becomes smaller, and then removal processing is started even on the most concave end plate surface. When the removal processing of the end plate surface is started, since the end plate surface is a relatively flat surface,
The contact pressure of the grindstone is uniformized and decreased.

Here, as described in the ultra-precision machining technology practical manual (edited by Akira Kobayashi et al., Published by New Technology Development Center, 1985, pp. 50-52), the contact pressure of the grindstone is chip. When the pressure is less than a certain pressure, the grindstone hardly generates chips, and only the plastic deformation (grindstone trace) is generated on the surface. In the polishing process, when the contact pressure is set so that the grindstone only causes plastic deformation at the time when the processing of the end plate surface, which is the accuracy standard, is started, if the end plate surface that is the accuracy standard is ground by pre-processing. Only the protruding portion of the streak is removed, and thereafter, even if the polishing operation continues, the progress of the removal process is stopped, and the streak of the grinding of the pre-process remains slightly on the end plate surface and the process is completed. You can

For this reason, the surface roughness becomes small on the end plate surface, but the dimension between the end plate surface and the bottom surface does not change at a practical level from the size obtained by the end surface grinding in the pre-processing. So the dimensions,
The end plate, which is the standard of the posture tolerance, is not removed until it affects the accuracy obtained by the end surface grinding in the pre-processing,
Polishing processing for improving the flatness and surface roughness of the mirror plate surface and the bottom surface is possible with a fixed scroll having no processing reference on the opposite side of the polishing surface. By the above grinding and polishing processing, it is possible to efficiently obtain a highly accurate fixed scroll without providing the flange surface and the top plate with a highly accurate reference surface necessary only for processing.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view showing, step by step, a method of processing a fixed scroll according to an embodiment of the present invention,
2 is a cross-sectional view schematically showing an example of the progress of processing and changes in the sectional shape of the fixed scroll in the polishing process of FIG. 1, and FIG. 3 is a line showing an example of accuracy change in the polishing process of FIG. FIG. 4 is a cross-sectional view schematically showing an example of a method of forming the cross-sectional shape of the fixed scroll before polishing shown in FIG. 2 by the end surface grinding processing shown in FIG. 1, and FIG. It is sectional drawing which expands and shows the difference between the surface state formed only by a process, and the surface state formed by the process which combined grinding process and polishing process.

In FIG. 1, 1 is a fixed scroll, 1a
Is an outer peripheral surface, 1b is a mirror plate surface, 1c is a tooth tip surface, 1d is a spiral scroll wrap (hereinafter simply referred to as wrap), 1e.
Is a bottom surface of the scroll groove, 1f is an outer surface, 1g is a flange surface, and 1h is a top plate. The outer peripheral surface 1a, the end plate surface 1b, and the tooth crest surface 1c are on the same plane, and the outer peripheral portion is the outer peripheral surface 1a and the oil groove 1 with the oil groove 1l formed on the circumference of the plane as a boundary.
A plane portion up to the scroll groove is a mirror plate surface 1b and a tooth tip portion of the scroll wrap is a tooth tip surface 1c. 2 is an outer peripheral chuck, 3 is a backing plate, 4 is an end mill, 5 is a measuring machine, 6 is an end grinding wheel, 7 is a pressing plate, 7a is a body, 7b is a sphere, 7c is a plate, and 8 is a grinding wheel.

First, as shown in FIG. 1 (a), the fixed scroll 1 after rough machining is inserted into the outer peripheral chuck 2 provided in the machining equipment (not shown) from the top plate 1h side, and the flange surface is inserted. With 1 g in contact with the backing plate 3, the outer surface 1 f is gripped by the claws that grip the outer circumferential chuck 2 in the horizontal direction, and the wrap 1 d is formed by cutting with the end mill 4. The outer surface 1f of the fixed scroll 1,
The flange surface 1g and the top plate 1h are in a rough cutting processing state, and a high-precision reference surface for processing is not provided.

Next, as shown in FIG. 1B, the mirror plate surface 1
Measuring machine 5 with the step size between b and bottom 1e always provided in the processing machine
To measure. After that, the measured values are fed back to the processing machine, and as shown in FIG. 1 (c), the outer peripheral surface 1a and the mirror plate surface are secured so that a desired finishing dimension between the mirror plate surface 1b and the bottom surface 1e of the fixed scroll 1 can be secured. 1b and the tooth crest 1c are ground by the end surface grinding wheel 6.

The processing of FIGS. 1 (a) to 1 (c) is carried out in the same equipment and in the same chuck state from the viewpoint of obtaining a good posture tolerance with respect to the mirror plate surface. Then, Figure 1
As shown in (d), the outer peripheral surface 1 of the fixed scroll 1 is attached to the disk-shaped grindstone 8 composed of relatively fine abrasive grains.
a, the end plate surface 1b and the tooth crest surface 1c are brought into contact with each other, and the grinding wheel 8
Then, the fixed scroll 1 is rotated and oscillated, and pressure is applied from the top plate 1h side through a pressure plate 7 having a universal joint mechanism using a sphere to perform polishing. The pressure plate may press the flange surface 1g.

The polishing process will be described in more detail with reference to FIG. In FIG. 2, 8 is a polishing grindstone, and 9 is a concavo-convex dimension between the end surfaces of the mirror plate surface. FIG. 2 is a side cross-sectional view showing an enlarged and simulated example of the shape change of the fixed scroll in the polishing process of FIG. FIG. 2 (a) shows an example of a state immediately before the start of polishing, in which the outer peripheral surface 1a and the end plate surface 1b of the fixed scroll 1 are on the same plane, and the tooth crest surface 1c projects from the end plate surface 1b. ing. Alternatively, the outer peripheral surface 1a may project more than the end plate surface 1b. In either case, the mirror plate surface 1b, which is the dimensional reference
Are recessed from the outer peripheral surface 1a and the tooth crest surface 1c.

An appropriate pressure is applied to the fixed scroll 1 via a pressure plate 7 having a universal joint structure using a sphere.
Add from the top plate 1h side. The pressure plate 7 is a body 7a.
Is connected to a pneumatically or hydraulically driven cylinder (not shown) for applying a force, and the force applied to the body 7a is applied to the sphere 7b.
To the plate 7c via. By using the pressurizing plate 7 having such a universal joint structure, it is possible to prevent the pressurizing surface from being unbalanced and exert an unbalanced load, and to apply a uniform pressure regardless of the accuracy of the top plate 1h which is a rough surface. Can be added. Further, even if the perpendicularity between the axis of the body 7a and the polishing grindstone 8 is not made highly accurate, it is possible to prevent the biased load from being applied, and it is easy to adjust the polishing apparatus.

The polishing grindstone 8 is bonded with polyvinyl alcohol, phenol resin, or the like, which is a material having appropriate elasticity, so as to follow the irregularities of the outer peripheral surface 1a, the end plate surface 1b and the tooth crest surface 1c and to be able to contact the entire surface. An elastic whetstone used as an agent is desirable. When the polishing process is started, a higher pressure is applied to the protruding portion with respect to the polishing grindstone 8, and the protruding portion of the tooth tip surface 1c is more positively removed and becomes flat. The end plate surface 1b, which is a standard for accuracy, is recessed from the tooth crest surface 1c, and the pressure to be applied is set so that the removal process does not start until the tooth crest surface 1c becomes flat.

FIG. 2 (b) shows a state in which the above-mentioned polishing process has progressed. The pressure applied to the outer peripheral surface 1a, the end plate surface 1b, and the tooth crest surface 1c to be machined becomes uniform by becoming flat, and at the same time, the fixed scroll 1 is lowered toward the grinding wheel 8 side. The relationship between the pressure of the grindstone applied to the surface to be machined and the amount of chips generated is described in the Super Precision Machining Manual (edited by Akira Kobayashi et al., Pp. 50-52, New Technology Development Center, 1985). As described above, when the pressure is high, chips are actively discharged to perform removal processing, but when the pressure drops below a certain pressure, the generation of chips is almost stopped on the surface to be processed, and the grinding stone Only the trace is generated by plastic deformation and becomes a processing area called a so-called friction area, and the removal processing does not proceed.

Therefore, as shown in FIG. 2 (b), the pressure applied to the top plate 1h via the pressure plate 7 is appropriately applied so that the removal processing of the polishing grindstone 8 does not proceed immediately after it becomes flat. Set it. Under the above conditions, the outer peripheral surface 1a and the tooth crests 1c are flat, and the most recessed end plate surface 1b.
Immediately after the removal is started, the polishing grindstone 8 does not discharge chips, and only the traces of the abrasive grains on the polishing grindstone 8 are plastically deformed on the mirror plate surface 1b.

By such processing, only the action of removing the convex portions formed by the abrasive grains of the end surface grinding grindstone in the pre-processing and smoothing the end plate surface 1b is given by the polishing grindstone, and the surface roughness of the end plate surface 1b is increased. Although the thickness is reduced, the mirror plate surface 1b is not removed until the dimension between the mirror plate surface 1b and the bottom surface 1e changes practically. In Table 1 and FIG. 3, in the processing example shown in FIG.
An example of change in polishing time and accuracy when polishing is performed by applying an average pressure of 10 kPa to a fixed scroll is shown.

[0046]

[Table 1] FIG. 3 shows changes in polishing time (s) on the horizontal axis and accuracy on the vertical axis. FIG. 3 (a) shows changes in the surface roughness (μmRz) of the end plate surface. (B) is the change in flatness (μm), and FIG. 3 (c) is the amount of dimensional change (μ) between the mirror plate surface and the bottom surface.
m) is shown. The flatness in FIG. 3B is indicated by the unevenness 9 between the end plate surface and the tooth crest surface shown in FIG. 2A, that is, the unevenness amount in the radial direction.

As shown in FIG. 3, a surface roughness of 0.5 μmRz and a flatness of 0.6 μm were obtained in a short time of 15 seconds, and good accuracy was obtained. At this time, the dimensional change between the mirror plate surface 1b and the bottom surface 1e was obtained. From the pre-processed state, it is as small as 0.3 μm, which is practically no problem. In addition, when the processing time is 15 seconds or more, the dimension between the mirror plate surface 1b and the bottom surface 1e does not change, and the mirror plate surface 1b
The removal processing of is stopped, and there is no need for delicate time management or dimensional measurement during processing. If the required accuracy is not high, the processing time can be further shortened.

As described above, by using the elastic grindstone and applying the appropriate pressure, the above-described polishing process hardly removes the end plate surface 1b, which is the standard of each accuracy. Practically, the dimensions and attitude tolerances with respect to the end plate surface 1b do not change the accuracy obtained by the end surface grinding in the pre-processing, and the outer peripheral surface 1 is flat and has a small surface roughness.
The polishing process is completed when a, the end plate surface 1b and the tooth crest surface 1c are obtained. Therefore, it is possible to efficiently perform the expected high-precision fixed scroll by making the end face grinding and polishing respectively suitable processing. End plate surface 1 after polishing
The feature b is characterized in that a slight amount of streaks due to the abrasive grains formed during the end face grinding process of the pre-processing remains.

Here, an example of a method for forming a fixed scroll having a sectional shape as shown in FIG. 2A in a pre-process of polishing will be described with reference to FIG. That is, the outer peripheral surface 1a is the same plane as the mirror plate surface 1b, or projects from the mirror plate surface 1b, and the tooth crest surface 1c projects from the mirror plate surface 1b, and the squareness between the mirror plate surface 1b and the lap 1d and the mirror plate surface 1b,
A method for obtaining the dimension between the bottom surfaces 1e and the parallelism will be described.

FIG. 4 (a) is an enlarged view of FIG. 1 (b). When the end mill finishing of the lap 1d is completed, the measuring machine 5 measures the dimension between the end plate surface 1b and the bottom surface 1e, and the next step This is a state in which the machining allowance due to the end surface grinding is measured. The outer surface 1f is gripped by the outer peripheral chuck 2, and the flange surface 1g is supported by the backing plate 3. In FIG. 4B, the end surface grinding wheel 6 has an outer peripheral surface 1a, an end plate surface 1b and a tooth crest surface 1c.
, And the grinding process is in progress, and the deformed state of the fixed scroll 1 is enlarged and schematically shown. Due to the force applied to the fixed scroll 1 by the end surface grinding wheel 6, the top plate 1h having a relatively thin structure is deformed so as to project, and the processing proceeds.

During such end surface grinding, the bottom surface probe 5b of the measuring machine 5 is retracted, and the mirror plate surface probe 5a continuously measures the remaining amount of the machining allowance of the mirror plate surface 1b. Since the mirror plate surface 1b measured by the mirror plate surface probe 5a is close to the supporting point of the backing plate 3 and has a relatively thick structure, the end surface grinding wheel 6
Highly accurate measurement is possible without being deformed by. End plate surface 1
In b, when the machining allowance measured before the start of machining is removed, the grinding machine stop command is output from the measuring machine 5, the end surface grinding is completed, and the desired dimension between the end plate surface 1b and the bottom surface 1e is obtained.

FIG. 4C shows the outer peripheral surface 1 after the end surface grinding is completed and the end surface grinding wheel 6 is separated from the processing point.
The shapes of a, the end plate surface 1b, and the tooth crest surface 1c are enlarged and shown in a simulated manner. That is, the tooth crest surface 1c formed on the top plate 1h projects from the end plate surface 1b when the deformation of the top plate 1h during end face grinding is restored, and the end plate surface 1b and the outer peripheral surface 1a are formed on the same surface. It

It should be noted that the end surface grinding wheel 6 projects so that the end face grinding wheel 6 projects toward the center of the tooth tip surface 1c so that the end surface 1b, which is a dimensional reference, does not project beyond the outer peripheral surface 1a, and the tooth tip surface after machining is finished. At a level where 1c is not recessed from the end plate surface 1b,
You may incline only by the minute angle (theta) suitably. By doing so, the outer peripheral surface 1a also forms the end plate surface 1b together with the tooth crest surface 1c.
It can be further projected, and the end surface 1b can be surely made the most concave. Through the above processing, the end plate surface 1b can be formed into a shape that does not protrude beyond the outer peripheral surface 1a and the tooth crest surface 1c, and the dimension between the bottom surface 1e with the end surface 1b as a reference can be improved.

Further, by performing end mill processing and end surface grinding processing while gripping the same chuck with the same equipment, the squareness of the lap 1d with respect to the mirror plate surface 1b is obtained, and the bottom surface with respect to the mirror plate surface 1b is obtained. The parallelism of 1e can be improved. Therefore, it is possible to obtain the shape used for the polishing process shown in FIG. In addition, such processing contents are
It can be easily achieved by setting the processing conditions, does not go through complicated steps, and is efficient.

Next, an example of the surface condition formed by the polishing process of FIG. 2 will be described with reference to FIG. Figure 5 (a)
Shows an example of a cross section of a surface formed by a conventional grinding wheel, but unevenness is present uniformly. When such a surface is formed on the outer peripheral surface 1a, the end plate surface 1b and the tooth crest surface 1c, gas leaks due to the unevenness,
It becomes a factor of gas inflow.

FIG. 5 (b) shows an example of the cross-sectional shape of the surface formed according to the present invention in the example of the mirror plate surface 1b. It is a surface that only exists. It should be noted that the ground surface of the tooth crest 1c disappears and becomes a completely polished surface.
It is better than the surface of (b). By providing such a surface, it is possible to reduce the gap between the parts to be combined and to supply a surface with a small sliding resistance, so that it is possible to provide an efficient scroll compressor.

According to this embodiment, it is possible to manufacture a fixed scroll with high accuracy without providing a machining reference surface which is unnecessary for the function of the compressor. And thereby, highly efficient processing can be implement | achieved rather than the conventional technique. Further, it is possible to perform processing by combining end face grinding and polishing, and it is possible to efficiently obtain a fixed scroll having an outer peripheral surface having a small flatness and surface roughness, an end plate surface, and a tooth top surface. Further, by providing the fixed scroll manufactured by the processing method according to the present embodiment, it is possible to provide a high performance and low cost scroll compressor.

[0058]

As described above in detail, according to the present invention, it is possible to provide a highly efficient and highly accurate method for machining a fixed scroll by omitting highly precise machining of a functionally unnecessary portion. Further, according to the present invention, it is possible to provide a method for processing a fixed scroll which enables processing in a step by a combination of grinding and polishing, obtains good accuracy, and is efficient. Further, according to the present invention, it is possible to provide a highly accurate fixed scroll without providing a functionally unnecessary processing standard, and contribute to reduction of power consumption and improvement of reliability of the compressor.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing, step by step, a method of processing a fixed scroll according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing an example of the progress of processing and changes in the cross-sectional shape of the fixed scroll in the polishing processing of FIG.

3 is a diagram showing an example of accuracy changes in the polishing process of FIG.

4 is a cross-sectional view schematically showing an example of a method of forming the cross-sectional shape of the fixed scroll before polishing shown in FIG. 2 by the end surface grinding process shown in FIG.

FIG. 5 is a cross-sectional view showing, in an enlarged scale, a difference between a surface state formed only by grinding and a surface state formed by a combination of grinding and polishing in the present embodiment. is there.

FIG. 6 is a cross-sectional view of a compression mechanism portion of a general scroll compressor.

7 is a cross-sectional view and a perspective view of the fixed scroll of FIG.

FIG. 8 is a cross-sectional view showing an example of a conventional method for processing a fixed scroll, step by step.

FIG. 9 is a cross-sectional view showing another example of a conventional method for processing a fixed scroll, step by step.

[Explanation of symbols]

1 ... Fixed scroll, 1a ... Outer peripheral surface, 1b ... End plate surface, 1
c ... Tooth surface, 1d ... Wrap, 1e ... Bottom surface, 1f ... Outer surface, 1g ... Flange surface, 1h ... Top plate, 2 ... Outer peripheral chuck, 3 ... Backing plate, 4 ... End mill, 5 ... Measuring machine, 6 ... Edge grinding wheel, 7 ... pressure plate, 7a ... body, 7b ... sphere, 7c ... plate, 8 ... polishing wheel.

Continuation of the front page (72) Inventor Tatsuo Horie 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Hitachi, Ltd. Living Equipment Division Cooling & Heat Headquarters (72) Inventor Masami Masuda 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture Hitachi, Ltd., Production Engineering Laboratory (72) Inventor Yukio Maeda, 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture, Ltd. Production Engineering Laboratory, Hitachi, Ltd. (72) Inventor Kazuya Kato Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture No. 292 Co., Ltd. Production Engineering Research Laboratory, Hitachi, Ltd.

Claims (3)

[Claims] 1. In a fixed scroll in which a spiral wrap stands upright from an end plate surface, the spiral wrap is cut and finished while gripping the roughened outer surface, flange surface, etc. of the fixed scroll, and then the fixed scroll is continuously cut. The outer peripheral surface, the end plate surface and the tooth top surface are ground, and the tip end surface is projected from the end surface and the outer peripheral surface. Is a fixed scroll satisfying the parallelism and the attitude tolerance of the wrap perpendicularity to the mirror plate surface, and further, with a very small machining allowance in the range where the abrasive grain scratches of the grinding process remain on the mirror plate surface, the outer peripheral surface The flatness and the surface roughness of the end plate surface and the tooth top surface are ensured, and the groove bottom dimension and the posture tolerance based on the end plate surface obtained by the grinding process are applied to the polishing process that practically does not change. That The fixed scroll to the butterflies. 2. A method for processing a fixed scroll in which a spiral wrap stands upright from the end plate surface, in which the outer surface, flange surface and top plate surface of the fixed scroll are rough-cut, and the rough-processed portion is gripped by a chuck. The first step of finishing the spiral wrap with, and grinding the outer peripheral surface, the end plate surface and the tooth tip surface of the fixed scroll while being held by the chuck, and denting the end plate surface from the outer peripheral surface and the tooth tip surface. The second step of forming by, and the outer peripheral surface after the second step, the mirror plate surface and the tooth tip surface is polished, and the polishing is performed in a state where the abrasive grain scratches of the grinding process remain on the mirror plate surface. A method of processing a fixed scroll, which comprises a third step of terminating. 3. A method for polishing the outer peripheral surface, end plate surface and tooth tip surface of a fixed scroll, wherein the outer peripheral surface, end plate surface and tooth tip surface of the fixed scroll are brought into contact with a rotating disk-shaped grindstone. While rotating and oscillating, a pressure is applied to the fixed scroll from a direction opposite to the end plate surface via a pressure plate having a universal joint structure configured by using a spherical body, and polishing is performed. The method for processing a fixed scroll according to claim 2.