EP2096313B1

EP2096313B1 - Positioning device for fixed scroll

Info

Publication number: EP2096313B1
Application number: EP07851098.9A
Authority: EP
Inventors: Takashi Hirouchi; Toshihiro Susa; Yasuto Hiraoka; Takahiro Kishimoto
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2006-12-28
Filing date: 2007-12-21
Publication date: 2018-02-21
Anticipated expiration: 2027-12-21
Also published as: EP2096313A4; WO2008081761A1; CN101573537B; CN101573537A; EP2096313A1; JP4135029B2; JP2008163839A

Description

Technical Field

The present invention relates to an apparatus for positioning a fixed scroll in assembling a scroll fluid machinery.

Background Art

Conventionally, scroll fluid machineries have been widely used in compressors and the like for compressing refrigerant in refrigerant circuits in air conditioners and the like. In the scroll fluid machineries, spiral wraps are provided to a fixed scroll and an orbiting scroll so that the fixed scroll wrap and the orbiting scroll wrap are meshed with each other to form fluid chambers. In the scroll fluid machineries, the orbiting scroll revolves to cause change in volume of the fluid chambers. For example, in a scroll compressor, after the fluid is sucked into fluid chambers before the fluid chambers are in a closed state, the fluid chambers in the closed state reduce in their volume to compress and then discharge the fluid in the fluid chambers.
As described above, in the scroll fluid machineries, the orbiting scroll revolves with the wrap thereof meshed with the fixed scroll wrap. If the orbiting scroll wrap strikes the fixed scroll wrap hard when the orbiting scroll revolves, the orbiting scroll moves awkwardly. Therefore, for moving the orbiting scroll smoothly, it is necessary to arrange the fixed scroll accurately at a position where the wrap of the revolving orbiting scroll strikes the fixed scroll wrap not so hard (a position where a minute clearance that allows a film of the lubricant oil to form between the wraps is formed all the time when the orbiting scroll revolves). For this reason, it is required to position the fixed scroll accurately in assembling a scroll fluid machinery. For accurately positioning the fixed scroll, apparatuses are disclosed, for example, in Patent Document 1.
In the positioning apparatus disclosed in Patent Document 1, an assembly is prepared which is an integrated combination of an orbiting scroll, a crank shaft engaged therewith, and a housing member forming a bearing for the crank shaft. In this assembly, the phase or the rotation angle of the crank shaft is detected in advance before the orbiting scroll is mounted. Then, the orbiting scroll of the assembly is meshed with a fixed scroll, and the crank shaft is rotated by a motor in this state. Next, variation in torque necessary for rotating the crank shaft is detected, and the contact degree and the contact direction (contact point) between the orbiting scroll and the fixed scroll are computed based on the variation in torque and the phase of the crank shaft (the phase of the orbiting scroll). Then, the distance and the direction in which the fixed scroll is to be moved are led out according to the contact degree and the contact direction between the orbiting scroll and the fixed scroll. Further, on the basis thereof, impact force (instant striking force) in the X-axis direction and the Y-axis direction, which are intersected at a right angle with each other, is applied to the fixed scroll with the fixed scroll pressed to the housing member, thereby moving the fixed scroll.
Patent Document 1: Japanese Unexamined Patent Application Publication 2006-207528 Document JP 2006 - 207529 discloses another apparatus for positioning the fixed scroll, similar to the one defined in independent claim 1.

Disclosure of the Invention

Problems that the Invention is to Solve

In Patent Document 1, since the orbiting scroll is mounted to the crank shaft after detection of the phase of the crank shaft, the phase of the crank shaft which the apparatus recognizes during the positioning process may become inaccurate because of assembling error. This invites positioning inaccuracy of the fixed scroll. Further, in order to detect the phase of the crank shaft prior to mounting of the fixed scroll, the detection must be performed after the phase detection mechanism is advanced above the crank shaft and the orbiting scroll must be mounted to the crank shaft after the phase detection mechanism is retreated. This complicates the operation.
The present invention has been made in view of the foregoing and has its object of achieving simple and accurate detection of the phase of a crank shaft (an orbiting scroll) in moving a fixed scroll for positioning thereof in assembling a scroll fluid machinery.

Means for Solving the Problems

A first aspect of the present invention is directed to a fixed scroll positioning apparatus for positioning, in a process for assembling a scroll fluid machinery (10), a fixed scroll (34) on the basis of a positional relationship between a wrap (35) of the fixed scroll (34) and a wrap (32) of an orbiting scroll (31), wherein the apparatus includes: a fixing member (63) fixing an assembly (11) which is an integrated combination of the orbiting scroll (31), a crank shaft (20) engaged with the orbiting scroll (31), and a housing member (36) forming a bearing for the crank shaft (20); a phase detection mechanism (90) detecting a phase or a rotation angle of the orbiting scroll (31); a moving mechanism (75) moving the fixed scroll (34) meshed with the orbiting scroll (31); and control means (80) controlling the moving mechanism (75) on the basis of a contact state of the wrap (35) of the fixed scroll (34) and the wrap (32) of the orbiting scroll (31) to position the fixed scroll (34).
In the apparatus, a to-be-detected part (31b) for phase detection is formed at the orbiting scroll (31) while a notch (34b) allowing the to-be-detected part (31b) to be observed from outside is formed in the fixed scroll, and the phase detection mechanism (90) includes a sensor (92) movable to a point facing the notch (34b) and detects the phase of the orbiting scroll (31) on the basis of position change of the to-be-detected part (31b) of the orbiting scroll (31) which is accompanied by rotation of the crank shaft (20).
In the first aspect, positioning of the fixed scroll (34) is performed in such a manner that the fixed scroll (34) is placed on the housing member (36) of the assembly (11) so that the wraps (32, 35) are meshed with each other and the fixed scroll (34) is moved by the moving mechanism (75) on the basis of the contact state of the wraps (32, 35). In the positioning, the sensor (92) of the phase detection mechanism (90) detects the to-be-detected part (31b) of the orbiting scroll (31) through the notch (34b) of the fixed scroll (34), so that the apparatus can recognizes the phase of the orbiting scroll (31) accurately. In other words, the fixed scroll (34) can be positioned with the phase of the orbiting scroll (31) recognized accurately.
A second aspect of the present invention is the first aspect, wherein the phase detection mechanism (90) includes a rotary encoder (53) connected to the crank shaft (20) and detects the phase of the orbiting scroll (31) all the time during rotation of the crank shaft (20) on the basis of a position of the to-be-detected part (31b) of the orbiting scroll (31) which is detected by the sensor (92) and a rotation position signal of the rotary encoder (53).
In the second aspect, the apparatus can recognize the phase of the orbiting scroll (31) all the time during rotation of the crank shaft (20) on the basis of the position of the to-be-detected part (31b) of the orbiting scroll (31) detected by the sensor (92) and the rotation position signal of the rotary encoder (53). Accordingly, the fixed scroll (34) can be positioned with the phase of the orbiting scroll (34) recognized more accurately.
A third aspect of the present invention is the first aspect or the second aspect, wherein the moving mechanism (75) includes a striking unit (70) moving the fixed scroll (34) by applying impact force to the fixed scroll (34) under a state that the fixed scroll (34) is pressed to the housing member (36).
In the third aspect, the fixed scroll (34) receives the impact force from the striking unit (70) to be moved. When the impact force is applied by the striking unit (70) to the fixed scroll (34) with the fixed scroll (34) pressed to the housing member (36), the fixed scroll (34) is moved by a minute distance.
In a fourth aspect of the present invention, the third aspect further includes: a guide (41) allowing the fixed scroll (34) to move in parallel to an X-axis direction and a Y-axis direction, which are intersected at a right angle with each other, with posture of the fixed scroll (34) unchanged, wherein the X-axis direction and the Y-axis direction in which the guide (41) allows the fixed scroll (34) to move agree with directions of the impact force that the moving mechanism (75) applies to the fixed scroll (34).
In the fourth aspect, the X-axis direction and the Y-axis direction in which the guide (41) allows the fixed scroll (34) to be moved agree with the directions of the moving force that the moving mechanism (75) applies to the fixed scroll (34). Hence, the fixed scroll (34) can be moved in parallel without being rotated.
A fifth aspect of the present invention is any one of the first to fourth aspects, wherein the to-be-detected part (31b) is formed at an outer peripheral part of the orbiting scroll (31) while the notch (34b) is formed in an outer peripheral part of the fixed scroll (34), and in an internal space of the casing (15) that the scroll fluid machinery (10) includes, an entirety of the inner space or at least a space on a side of the notch (64b) of the fixed scroll (34) serves as a low-pressure space filled with low-pressure gas.
In the fifth aspect, in the internal space of the casing (15) that the scroll fluid machinery (10) includes, the entirety of the inner space or at least the space on the side of the notch (34b) of the fixed scroll (34) serves as the low-pressure space filled with the low-pressure gas. In the scroll fluid machinery, which may be a compressor or an expansion engine, the outer peripheral side of the spiral is low in pressure, and therefore, high-pressure gas may be introduced into the spiral through the notch (34b) in operation if the space of the casing (15) serves as a high-pressure space. In contrast, when the space is the low-pressure space, such a problem is obviated during operation. When the notch (34b) is covered after positioning the fixed scroll (34), no influence is involved even if the space serves as the high-pressure space, of course.

Effects of the Invention

In the present invention, in positioning the fixed scroll (34) in such a manner that the fixed scroll (34) is placed on the housing member (36) of the assembly (11) so that the wraps (32, 35) are meshed with each other and the fixed scroll (34) is moved by the moving mechanism (75) on the basis of the contact state of the wraps (32, 35), the phase detection mechanism (90) detects the to-be-detected part (31b) of the orbiting scroll (31) through the notch (34b) of the fixed scroll (34), so that the apparatus can recognize the phase of the orbiting scroll (31) accurately. Since the fixed scroll (34) can be positioned with the phase of the orbiting scroll (31) recognized accurately, influence of assembling error is obviated dislike the conventional one in which positioning is performed after phase detection, thereby achieving accurate phase detection and positioning. Further, phase detection can be performed while positioning is performed, thereby preventing the assembling process from being complicated.
In the second aspect of the present invention, the apparatus can recognize the phase of the orbiting scroll (31) all the time during rotation of the crank shaft (20) on the basis of the position of the to-be-detected part (31b) of the orbiting scroll (31) detected by the sensor (92) of the phase detection mechanism (90) and the rotation position signal of the rotary encoder (53). Since the fixed scroll (34) can be positioned with the phase of the orbiting scroll (31) recognized more accurately, the positioning accuracy increases.
In the third aspect of the present invention, the striking unit (70) applies the impact force to the fixed scroll (34) with the fixed scroll (34) pressed to the housing member (36). This moves the fixed scroll (34) by a minute distance to achieve precise positioning of the fixed scroll (34).
In the fourth aspect of the present invention, the X-axis direction and the Y-axis direction in which the guide (41) allows the fixed scroll (34) to be moved agree with the directions of the impact force that the moving mechanism (75) applies to the fixed scroll (34). Accordingly, the fixed scroll (34) can be positioned by parallel movement thereof without rotation. Hence, the positioning accuracy increases further.
In the fifth aspect of the present invention, in the internal space of the casing (15) that the scroll fluid machinery (10) includes, the entirety of the inner space or at least the space on the side of the notch (34b) of the fixed scroll (34) serves as the low-pressure space filled with the low-pressure gas. In the scroll fluid machinery, which may be a compressor or an expansion engine, the outer peripheral side of the spiral is low in pressure, and therefore, high-pressure gas may be introduced into the spiral through the notch (34b) in operation if the space in the casing (15) serves as a high-pressure space. In contrast, when the space is the low-pressure space, such a problem is obviated during operation. Hence, the scroll fluid machinery (10) can function normally as a product with the notch (34b) remaining in the fixed scroll (34). The space may serve as the high-pressure space if the notch (34b) is covered after positioning the fixed scroll (34).

Brief Description of the Drawings

[FIG. 1] FIG. 1 is a vertical sectional view of a scroll compressor in accordance with an embodiment of the present invention.
[FIG. 2] FIG. 2 is a transverse sectional view of a compression mechanism.
[FIG. 3] FIG. 3 is a constructional diagram of a positioning apparatus in accordance with the embodiment of the present invention.
[FIG. 4] FIG. 4 is a perspective view showing an X-Y guide of the positioning apparatus.
[FIG. 5] FIG. 5 is a layout diagram of striking units in the positioning apparatus.
[FIG. 6] FIG. 6 is a constructional diagram of the striking units.
[FIG. 7] FIG. 7 is a block diagram showing control of the positioning apparatus.
[FIG. 8] FIG. 8 is a plan view of an assembly before a fixed scroll is mounted thereto.
[FIG. 9] FIG. 9 is a plan view of the assembly after the fixed scroll is mounted thereto.
[FIG. 10] FIG. 10 is a plan view of an orbiting scroll.
[FIG. 11] FIG. 11 is a plan view of the fixed scroll.
[FIG. 12] FIG. 12 shows a first setup step of a positioning method.
[FIG. 13 ] FIG. 3 shows a second setup step of the positioning method.
[FIG. 14] FIG. 14 shows a third setup step of the positioning method.
[FIG. 15] FIG. 15 shows a fourth setup step of the positioning method.
[FIG. 16] FIG. 16 shows a fifth setup step of the positioning method.
[FIG. 17] FIG. 17 shows a step of conveying the assembly to the positioning apparatus.
[FIG. 18] FIG. 18 shows a first centering step of the positioning method.
[FIG. 19] FIG. 19 shows a second centering step of the positioning method.
[FIG. 20] FIG. 20 shows a third centering step of the positioning method.
[FIG. 21] FIG. 21 shows a fourth centering step of the positioning method.
[FIG. 22] FIG. 22 shows a fifth centering step of the positioning method.
[FIG. 23] FIG. 23 shows a sixth centering step of the positioning method.
[FIG. 24] FIG. 24 shows a seventh centering step of the positioning method.
[FIG. 25] FIG. 25 is a plan view showing the relationship between the position of the fixed scroll and the striking unit.
[FIG. 26] FIG. 26 is a plan view showing the relationship between the position of the fixed scroll and the striking units.
[FIG. 27] FIG. 27 shows an eighth centering step of the positioning method.
[FIG. 28] FIG. 28 shows a ninth centering step of the positioning method.
[FIG. 29] FIG. 29 shows a step of conveying the assembly out from the positioning apparatus.

Explanation of Reference Numerals

10: scroll fluid machinery (scroll compressor)
11: assembly
20: crank shaft
31: orbiting scroll
32: wrap (fixed scroll wrap)
34: fixed scroll
35: wrap (fixed scroll wrap)
36: housing (housing member)
40: positioning apparatus (centering/assembling facility)
41: guide
63: cramp mechanism (fixing member)
65: position detection mechanism
70: striking unit
75: moving mechanism
80: control means (controller)
90: phase detection mechanism

Best mode for Carrying out the Invention

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. Wherein, the construction of a scroll compressor (10) assembled with the use of a positioning apparatus (40) in accordance with the present invention will be described first, followed by description of the positioning apparatus (40) and a positioning method in accordance with the present embodiment.

-Construction of Scroll Compressor-

As shown in FIG. 1 , the scroll compressor (10) is of generally-called hermetic type. The scroll compressor (10) includes a casing (15) formed of an oblong hermetic container. The casing (15) is composed of one body member (16) formed in an oblong cylindrical shape and cup-shaped heads (17, 18) mounted at the upper end and the lower end of the body member (16).
Inside the casing (15), a lower bearing member (23), a compressor motor (25), a compression mechanism (30) are arranged in this order from the bottom to the above. A vertically extending crank shaft (20) is also provided inside the casing (15).
A suction pipe (11) passing through the upper head (17) is fixed at the casing, (15) so as to communicate with the suction port of the compression mechanism (30). Further, a discharge pipe (12) passing through the body member (16) is provided at a part of the casing (15) between the compression mechanism (30) and the compressor motor (25). Low-pressure gas is sucked into the compression mechanism (30) through the suction pipe (11), is compressed in the compression mechanism (30) to be high-pressure gas, fills the space in the lower part of the compression mechanism (30) in the casing (15), and is then discharged from the discharge pipe (12). Inside of the casing (15), the upper space (S1) of the compression mechanism (20) serves as a low-pressure space while the lower space (S2) thereof serves as a high-pressure space.
The crank shaft (20) includes a main shaft portion (21) and an eccentric portion (22). The main shaft portion (21) has an upper end part of which diameter is slightly larger than that of the lower part thereof. The eccentric portion (22) is in a column shape having a diameter smaller than that of the upper end part of the main shaft portion (21) and stands on the upper end face of the main shaft portion (21). The axial center of the eccentric portion (22) is eccentric from the axial center of the main shaft part (21).
The lower bearing member (23) is fixed in the vicinity of the lower end of the body member (16) of the casing (15). A sliding bearing (23a) is formed at the central part of the lower bearing member (23) to support the lower end of the main shaft portion (21) rotatably.
The compressor motor (25) is a generally-called brushless DC motor. The compressor motor (25) includes a stator (26) and a rotor (27) to compose a driving motor. The stator (26) is fixed to the body member (16) of the casing (15). The stator (26) is connected electrically to a feeder terminal (19) mounted at the body member (16) of the casing (15). On the other hand, the rotor (26) is arranged inside the stator (26) so as to be fixed to the main shaft portion (21) of the crank shaft (20).
The compression mechanism (30) includes an orbiting scroll (31), a fixed scroll (34), and a housing (36) as a housing member (36).
The housing (36) is in a comparatively thick disc shape of which central part is recessed, wherein the outer peripheral part thereof is joined to the upper end of the body member (16). The main shaft portion (21) of the crank shaft (20) is inserted in the central part of the housing (36). The housing (36) composes a bearing (36a) rotatably supporting the main shaft portion (21) of the crank shaft (20).
The orbiting scroll (31) includes an orbiting scroll end plate (31a), an orbiting scroll wrap (32) in a spiral shape standing on the front face thereof (the upper face in FIG. 1 ), and a cylindrical protrusion (33) protruding from the back face thereof (the lower face in FIG. 1 ). Though not shown in FIG. 1 , the orbiting scroll (31) is placed on the upper face of the housing (36) with an Oldham ring (39) shown in FIG. 13 interposed. The eccentric portion (22) of the crank shaft (20) is inserted in the protrusion (33) of the orbiting scroll (31). In other words, the orbiting scroll (31) is engaged with the crank shaft (20).
The fixed scroll (34) is in a comparatively thick disc shape and includes a fixed scroll end plate (34a). A fixed scroll wrap (35) in a spiral shape is provided at the central part of the fixed scroll (34). The fixed scroll wrap (35) is formed by engraving the fixed scroll (34) from the lower face thereof.
As shown in FIG. 2 , the fixed scroll wrap (35) of the fixed scroll (34) and the orbiting scroll wrap (32) of the orbiting scroll (31) are meshed with each other in the compression mechanism (30). Meshing of the fixed scroll wrap (35) and the orbiting scroll wrap (32) with each other forms a plurality of compression chambers (37) between the outer peripheral face of the fixed scroll wrap (35) and the inner peripheral face of the orbiting scroll wrap (32) and between the inner peripheral face of the fixed scroll wrap (35) and the outer peripheral face of the orbiting scroll wrap (32).

-Fixed Scroll Positioning Apparatus-

The positioning apparatus (40) of the present embodiment is provided for positioning the fixed scroll (34) on the basis of the positional relationship between the fixed scroll wrap (35) and the orbiting scroll wrap (32) in a process of assembling the scroll compressor (10). Specifically, the positioning apparatus (40) appropriates the positional relationship between the fixed scroll (34) and the orbiting scroll (31) by adjusting the position of the fixed scroll (34) in mounting the fixed scroll (34) to a later-described assembly (11) prepared in the process of assembling the scroll compressor (10).
The assembly (11) is an assembled integration of the body member (16), the housing (36), the compressor motor (25), the lower bearing member (23), the crank shaft (20), and the orbiting scroll (31). In the assembly (11), the housing (36), the compressor motor (25), and the lower bearing member (23) are fixed to the body member (16), and the orbiting scroll (31) engaged with the crank shaft (20) is placed on the housing (36). The stator (26) of the compressor motor (25) is connected electrically to the feeder terminal (19) in the assembly (11).
The construction of the positioning apparatus (40) will be described with reference to FIG. 3 . The positioning apparatus (40) includes a first frame (45) and a second frame (60).
The first frame (45) includes one pedestal (46), one upper plate (47), and four poles (48). The pedestal (46) is formed in a rectangular shape and is arranged substantially horizontally. The poles (48) stand at the corners of the pedestal (46). The poles (48) pass through the pedestal (46) and protrude at the lower ends thereof downward from the pedestal (46). The upper plate (47) is fixed at the upper ends of the four standing poles (48).
A cylindrical guide member (50) protrudes from the central part of the upper face of the pedestal (46). The guide member (50) is provided for guiding the body member (16) to a predetermined point when the assembly (11) is placed on the pedestal (46), and has an inner diameter slightly larger than the outer diameter of the body member (16). A through hole (52) is formed at the center of the pedestal (46). The through hole (52) is a circular hole formed coaxially with the guide member (50) and passes through the pedestal (46).
A rotary encoder (53) is mounted at the lower face of the pedestal (46) through a bracket (54). The rotary encoder (53) is arranged under the through hole (52) and has a rotating shaft (53a) extending upward toward the through hole (52). A coupling (55) is mounted at the rotating shaft (53a) of the rotary encoder (53). The coupling (55) joins the rotating shaft (53a) of the rotary encoder (53) and a part of an oil pickup (20a) at the lower end of the crank shaft (20) which protrudes downward from the through hole (52). Though not shown in FIG. 1 , the oil pickup (20a) is formed integrally with the crank shaft (20), as shown in FIG. 3 . The oil pickup is fitted to an oil pump (not shown) to supply a lubricant oil to bearings and sliding elements of the compression mechanism (30) through an oil supply passage (not shown) vertically extending in the central part of the crank shaft (20).
A pressing mechanism (56) for pressing the fixed scroll (34) downward is mounted at the upper plate (47). The pressing mechanism (56) includes a downwardly extending rod (57a) and is arranged substantially at the center of the upper plate (47). A pressing member (58) larger in sectional area than the rod (57a) is mounted at the lower end of the rod (57a). A guide (41), which will be described later, is mounted at the lower face of the pressing member (58). The pressing mechanism (58) feeds the rod (57a) by an air cylinder (57) or the like to move the pressing member (58) and the guide (41) downward to apply the pressing force to the fixed scroll (34).
The guide (41) will be described with reference to FIG. 4 . The guide (41) includes a base plate (59), an X-axis rail (49a) and a Y-axis rail (49b) intersected at a right angle with each other, linear motion bearings (51) engaged with the X-axis rail (49a) and the Y-axis rail (49b), and three presser rods (28) provided at the lower face of the base plate (59) as shown in FIG. 3 .
the X-axis rail (49a) includes two rail members having the same length. The two rail members of the X-axis rail (49a) are arranged and fixed in parallel to each other with a predetermined space left on the upper face of the base plate (59). The Y-axis rail (49b) includes two rail members having the same length. The two rail members of the Y-axis rail (49b) are arranged and fixed in parallel to each other with a predetermined space left on the lower face of the pressing member (58).
A spike (28a) for inhibiting rotation of the fixed scroll (34) is formed at each lower end of the presser rods (28). The presser rods (28) inhibit sliding of the fixed scroll (34) on the guide (41) when the fixed scroll (34) is moved in the state that the guide (41) applies the pressing force to the fixed scroll (34). Provision of the spike (28a) at each lower end of the presser rods (28) generates, at the contact face between the presser rods (28) and the fixed scroll (34), larger frictional force than the frictional force generated at the contact face between the fixed scroll (34) and the housing (36).
The respective linear motion bearings (51) are provided at the parts where the X-axis rail (49a) and the Y-axis rail (49b) are intersected with each other. In other words, the guide (41) is provided with the linear motion bearings (51) of which number is four in total. The linear motion bearings (51) are substantially in a cubic shape having a lower face in which a groove in the X-axis direction is formed and an upper face in which a groove in the Y-axis direction is formed. The X-axis rail (49a) is fitted in the groove in each lower face of the linear motion bearings (51) while the Y-axis rail (49b) is fitted in the groove in each upper face thereof. The linear motion bearings (51) are prevented from falling off in the Z-axis direction (the direction at a right angle with respect to the plane of the base plate (59)). Multiple ball members not shown are embedded in the grooves in the X-axis direction and the Y-axis direction of the linear motion bearings (51). Each linear motion bearing (51) is in contact with the X-axis rail (49a) and the Y-axis rail (49b) with the multiple ball members interposed so as to have a rolling guide structure that moves straight along the rails. Whereby, the guide (41) allows the parallel movement of the fixed scroll (34) in the X-axis direction and the Y-axis direction that are right-angled to each other while restricting rotation of the fixed scroll (34) under the state where the pressing force is applied to the fixed scroll (34).
The second frame (60) includes one frame member (61) and four poles (62) and is fixed on the pedestal (46). The length of the poles (62) is slightly shorter than the height of the body member (16) composing the assembly (11). The four poles (62) stand around the guide member (50) at regular intervals on the pedestal (46). The frame member (61) is in a rectangular or circular frame shape and is placed on the four poles (62). The frame member (61) is fixed to the poles (62) so as to surround the upper part of the assembly (11).
The frame member (61) is provided with a cramp mechanism (63) for fixing the assembly (11). The cramp mechanism (63) serves as a fixing member. The cramp mechanism (63) includes a plurality of movable cramp heads (64) protruding inward from the frame member (61). The cramp mechanism (63) allows the cramp heads (64) to push the outer peripheral face of the body member (16) composing the assembly (11) to clip the sides of the assembly (11) in the radial direction of the body member (16), thereby holding the assembly (11). Favorably, four cramp heads (64) in total are provided on the radial lines in the X-axis direction and the Y-axis direction, for example.
On the frame member (61), there are provided two position detection mechanisms (65) for detecting the position of the fixed scroll (34) in the X-axis direction and the Y-axis direction and four striking units (70) arranged two by two on the X-axis and the Y-axis. Electric micrometers (66), for example, may be used as the position detection mechanisms (65). The electric micrometers (66) measure the position and the dimension of a measurement target by utilizing an electric signal. As the position detection mechanisms (65), any other position measuring tools, such as laser displacement gauges or the like may be used rather than the electric micrometers (66). The laser displacement gauges measure displacement of the fixed scroll (34) from reflected light of a laser beam irradiated on the fixed scroll (34).
The striking units (70) are in a circular column shape and each include a head (74) at the extreme end at which a projection is formed (see FIG. 6 ). The four striking units (70) serve as a moving mechanism (75) for moving the fixed scroll (34) by applying impact force to the fixed scroll (34).
As shown in FIG. 5 , the four striking units (70) are arranged radially at the intervals of 90 degrees with the fixed scroll (34) on the housing (36) of the assembly (11) as a center. In other words, two striking units (70) are arranged along a first radial direction (the X-axis direction) of the fixed scroll (34) while the other two striking units (70) are arranged along a second radial direction (the Y-axis direction) intersected at a right angle with the first radial direction. The projection of the head (74) of each striking unit (70) faces the fixed scroll (34). Namely, each two striking units (70) arranged along one of the radial directions faces each other with the fixed scroll (34) interposed.
The first radial direction is parallel to the X-axis direction of the guide (41). The second radial direction is parallel to the Y-axis direction of the guide (41). Namely, the X-axis direction and the Y-axis direction in which the guide (41) allows the movement of the fixed scroll (34) agree with the directions of the impact force that the striking units (70) apply to the fixed scroll (34). When one of the striking units (70) applies the impact force in the X-axis direction to the fixed scroll (34), the X-axis rail (49a) is guided to the grooves in the X-axis direction of the linear motion beatings (51), thereby moving the fixed scroll (34) in the X-axis direction. On the other hand, when one of the striking units (70) applies the impact force in the Y-axis direction to the fixed scroll (34), the Y-axis rail (49b) is guided to the grooves in the Y-axis direction of the linear motion beatings (51), thereby moving the fixed scroll (34) in the Y-axis direction.
A construction of the striking units (70) will be described with reference to FIG. 6 . Each striking unit (70) includes one main body (1) and one air cylinder (100). The main body (71) and the air cylinder (100) have cylindrical outer shapes and are arranged coaxially with each other.
The main body (71) includes a base part (72), a piezoelectric element (72), and a head (74) and is formed into a column shape as a whole. Specifically, in the main body (71), the base part (72) and the head (74), both of which are formed in column shapes are arranged coaxially with each other, and the piezoelectric element (73) is interposed between the base part (72) and the head (74). The projection is formed at the tip end (on the side opposite to the piezoelectric element (73)) of the head (74). In the main body (71), when voltage is applied to the piezoelectric element (73), the piezoelectric element (73) extends in the axial direction of the main body (71) to push out the head (74) (see FIG. 6B ). When the electric conduction to the piezoelectric element (73) is stopped, the piezoelectric element (73) returns to have the original length, thereby returning the head (74) (see FIG. 6(A) ).
The air cylinder (100) includes a cylinder (102), a piston (102), and a rod (103). The cylinder (101) has a hollowed cylindrical shape. The piston (102) is inserted in the cylinder (101) so as to be movable in the axial direction of the cylinder (101). The rod (103) is arranged coaxially with the cylinder (101). The rod (103) is connected at the base end thereof to the piston (102) while extending at the tip end thereof outside the cylinder (101). The tip end of the rod (103) is joined to the end face of the base part (72) of the main body (71). The inside of the cylinder (101) is divided by the piston (102) into a first air chamber (104) and the a second air camber (105). A first air pipe (106) is connected to the first air chamber (104) located on the opposite side to the rod (103) while a second air pipe (107) is connected to the second air chamber (105) located on the rode (103) side.
In each of the striking units (70), when the air is supplied from the first air pipe (106) to the first air chamber (104) while at the same time the air is discharged from the second air chamber (105) to the second air pipe (107), the piston (102) moves toward the second air chamber (105) to send out the main body (71) toward the tip end of the striking unit (70) (leftward in FIG. 6 ). In reverse, when the air is supplied from the second air pipe (107) to the second air chamber (105) while at the same time the air is discharged from the first air chamber (104) to the first air pipe (106), the piston (102) moves toward the first air chamber (104) to return the main body (71) backward toward the base end of the striking unit (70) (rightward in FIG. 6 ).
As shown in FIG. 7 , the positioning apparatus (40) includes an inverter (81), a driver (82) for the inverter (81), and a controller (control means) (80). The inverter (81) and the driver (82) compose feeding means (83).
The inverter (81) is connected at the input side thereof to a commercial power source (85) while being connected at the output side thereof to the feeder terminal (19) of the assembly (11). The driver (82) receives an output signal from the rotary encoder (53).
The positioning apparatus (40) includes, though not shown in FIG. 7 , a laser displacement gauge (91) for measuring the phase of the crank shaft (20) (see FIG. 18 ). The laser displacement gauge (91) for phase measurement measures the phases of the crank shaft (20) and the orbiting scroll (31) and composes a phase detection mechanism (90) in the present invention in combination with the rotary encoder (53).
The driver (82) computes the rotation angle and the angular velocity of the crank shaft (20) on the basis of the output signal of the rotary encoder (53) and sets, according thereto, an instruction value in relation to the output current value and the output frequency of the inverter (81). The driver (82) then outputs an instruction, such as switching timing or the like to the inverter (81) so that the output of the inverter (81) corresponds to the instruction value. The inverter (81) is operated in accordance with the instruction from the driver (82) to supply the alternating current to the compressor motor (25) of the assembly (11). The controller (80) receives an instruction value in relation to the output current of the inverter (81) and information on the rotation angle of the crank shaft (20) from the driver (82).
While allowing the rotary encoder (53) to detect a predetermined rotation point (phase) of the orbiting scroll (31) during the time when the crank shaft (20) is rotated, the controller (80) determines the direction in which the fixed scroll (34) is to be moved on the basis of the phase or the rotation angle of the orbiting scroll (31). Further, the controller (80) allows the striking units (70) to move the fixed scroll (35) by a predetermined distance (about several microns to ten microns) in the direction in which the outer peripheral face of the fixed scroll wrap (35) separates from the inner peripheral face of the orbiting scroll wrap (32) in a predetermined part of the fixed scroll (34) and performs then control for inverting the orbiting scroll (31) by approximately 180°. In so doing, the outer peripheral face of the orbiting scroll wrap (32) is in contact with the inner peripheral face of the fixed scroll wrap (35) to cause the fixed scroll (34) to shift by the repulsive force of the orbiting scroll wrap (32). Upon detection of the shift of the fixed scroll (34) by the electric micrometers (66), the position of the predetermined part thereof is recognized as a limit point of a movable range of the fixed scroll (34). On the other hand, when the fixed scroll (34) does not shift when the orbiting scroll (31) is inverted after striking of the fixed scroll (34), which means that the wraps (32, 35) are out of contact with each other yet and the fixed scroll (34) does not reach the limit point of the movable range, striking of the fixed scroll (34) and inversion of the orbiting scroll (31) are repeated until the wraps (31, 35) are in contact with each other.
When the above operation is performed in the plus direction (first direction) and the minus direction (second direction) on the X-axis, each end of the movable range on the X-axis of the fixed scroll (34) can be detected. Then, the fixed scroll (34) is moved to the center on the X-axis of the movable range thereof. Next, after the same operation is performed in the plus direction and the minus direction on the Y-axis, the fixed scroll (34) is moved to the center on the Y-axis of the movable range thereof. At this time point, the fixed scroll (34) is positioned almost at the center though the first centering operation in the X-axis direction was performed with no center on the Y-axis determined. Therefore, in order to perform more precise centering, in the present embodiment, control is performed so that the same operation is performed in the plus direction and the minus direction on the X-axis again for setting the fixed scroll (34) at the center of the movable range thereof.
The detailed control of the striking units (70) is followed. When the direction in which the fixed scroll (34) is to be moved is determined from the singal of the phase detection mechanisms (90), the controller (80) controls a striking unit (70) corresponding to the determined direction. Specifically, the controller (80) first allows the first air pipe (106) to supply the air to the first air chamber (104) while allowing the second air chamber (105) to discharge the air to the second air pipe (107) to move the main body (71) so that the projection of the head (74) of the striking unit (70) is in contact with the fixed scroll (34). After the striking unit (70) is moved, the controller (80) applies pulse voltage to the piezoelectric element (73) of the striking unit (70). Upon application of the pulse voltage to the piezoelectric element (73) of the striking unit (70), the piezoelectric element (73) extends and contracts according to the pulse waveform. Accordingly, the inertia force of the head (74) pushed out by the extension of the piezoelectric element (73) works on the fixed scroll (34) to move the fixed scroll (34) slightly (by about several microns to ten microns). Movement of the fixed scroll (34) results in separation of the head (74) from the fixed scroll (34). Accordingly, the striking unit (70) is moved so that the projection of the head (74) is in contact with the fixed scroll (34) again, and the pulse voltage is applied again to the piezoelectric element (73) of the striking unit (70) to move the fixed scroll (34) slightly by extension and contraction of the piezoelectric element (73). Repetition of this operation moves the fixed scroll (34) pressed to the housing (36) little by little. After the movement of the fixed scroll (34) is terminated, the controller (80) allows the second air pipe (107) to supply the air to the second air chamber (105) while allowing the first air chamber (104) to discharge the air to the first air pipe (106) to return the striking unit (70) to the original position.
This operation of the controller (80) will be described with reference to FIG. 5 . The terms in this paragraph, "right," "left," "up," and "down (lower)" correspond to those in FIG. 5 . For example, for moving the fixed scroll (34) leftward (or rightward) on the X-axis, the controller (80) controls the right (or left) striking unit (70). Specifically, the controller (80) adjusts the air amounts in the first air chamber (104) and the second air chamber (105) of the air cylinder (100) for moving the main body (71) and supplies the pulse voltage to the piezoelectric element (73) of the main body (71) for applying the leftward (or rightward) impact force to the fixed scroll (34). For moving the fixed scroll (34) downward (or upward) on the Y-axis, the controller (80) controls the upper (or lower) striking unit (70).

-Structures of Fixed Scroll and Orbiting Scroll-

FIG. 8 is a plan view showing the assembly (11) obtained by assembling the body member (16), the housing (36), the compressor motor (25), the lower bearing member (23), the crank shaft (20), and the orbiting scroll (31), and FIG. 9 is a plan view of the assembly (11) to which the fixed scroll (34) is set. FIG. 10 is a plan view of the orbiting scroll (31), and FIG. 11 is a plan view of the fixed scroll (34).
The orbiting scroll (31) includes at three parts on the outer peripheral face of the orbiting scroll end plate (31a) outer peripheral protrusions (31b) protruding outward in the radial direction for dynamic balance. Notches (34b) for weight reduction are formed at three parts on the outer peripheral edge of the fixed scroll end plate (34a) of the fixed scroll (34).
As shown in FIG. 8 , the housing (36) is provided with four mounting parts (36b) for mounting the fixed scroll (34). In each of the mounting parts (36b), there are formed two housing positioning pin holes (36c) receiving positioning pins (38a) (see FIG. 14 ) for positioning the fixed scroll (34) and five bolt holes (36d) for fastening the fixed scroll (34) by means of bolts (38b) (see FIG. 15 ).
In the fixed scroll (34), there are formed two fixed scroll positioning pin holes (34c) at points corresponding to the housing positioning pin holes (36c) and five bolt holes (34d) at points corresponding to the bolt holes (36d) of the housing (36). The fixed scroll (34) is positioned provisionally by the positioning pins (38a) to the housing (36) and is then fixed to the housing (36) by means of the bolts (38b). FIG. 9 shows this state.
In the state shown in FIG. 9 , movement of the outer peripheral protrusions (31b) can be observed as rotation of the orbiting scroll (31) through the notches (34b) of the fixed scroll (34). The outer peripheral protrusions (31b) of the orbiting scroll (31) are observed through the notches (34b) of the fixed scroll (34) in this way for phase detection of the orbiting scroll (31). Specifically, a sensor (92) (see FIG. 18 ) of the laser displacement gauge (91) composing the phase detection mechanism (90) is arranged above the notches (34b) for detecting the outer peripheral protrusions (31b) of the orbiting scroll (31), and the phase of the crank shaft (20), that is, the phase of the orbiting scroll (31) during rotation of the compressor motor (25) is detected on the basis of the detected positions of the outer peripheral protrusions (31b) and the rotation position signal of the rotary encoder (53). Namely, the outer peripheral protrusions (31b) serve as to-be-detected parts (31b) of the orbiting scroll (31) for phase detection.
The positioning pin holes (34c, 36c) are formed in the outer peripheral parts of the housing (36) and the fixed scroll (34), respectively. The clearance of the positioning pin holes (34c, 36c) is set precisely in the range of, for example, 30 µm ± 10 µm with respect to the diameter of the positioning pins (38a). Suppose that the pitch diameter of the positioning pin holes (34c, 36c) is ϕ130 mm, displacement in the rotation (θ) direction is approximately 1.5 µm or smaller though it differs slightly according to the base circle diameter, and accordingly, sufficient position accuracy can be achieved in the θ direction.

-Method for Poisoning Fixed Scroll (34)-

A method for positioning the fixed scroll (34) which the positioning apparatus (40) performs will be described with the method divided into a fixing step including setup steps before positioning the fixed scroll (34) and a fixed scroll (34) positioning step. The description will be given in this order.
FIG. 12 to FIG. 16 show the setup steps before positioning the fixed scroll (34). In the first setup step shown in FIG. 12 , a refrigerator oil (96) used as a lubricant oil is injected to the bearing (36a) of the housing (36) under the state that the assembly (11) before the orbiting scroll (31) is fitted to the crank shaft (20) is placed on a conveyance pallet (95) with the housing (36) located up. As the lubricant oil (96), a refrigerator oil (96) is used which has viscosity lower than the refrigerator oil (96) used for the scroll compressor (10) after assembled. For example, in the case where the viscosity of the refrigerator oil (96) used for a compressor after assembled is VG68, an oil having a low viscosity of VG32, VG22, or the like is used as the lubricant oil (96) for the assembling process. An oil having high viscosity is supplied to the bearings non-uniformly especially at low outdoor temperature, so that the oil film formed becomes non-uniform in thickness at low-speed rotation, for example, at the positioning step to invite assembling with the center of the crank shaft (20) displaced. In contrast, the use of the oil having such low viscosity prevents displacement of the center of the crank shaft (20) in the assembling process. If an oil having low viscosity is supplied to the bearing (23a) of the lower bearing member (32) in advance, displacement of the center of the crank shaft (20) can be prevented further effectively.
In a second setup step shown in FIG. 13 , the Oldham ring (39) and the orbiting scroll (31) are mounted to the assembly (11), and the lubricant oil (96) is injected to the sliding elements. As the lubricant oil (96), the refrigerator oil (96) is used which has viscosity lower than the refrigerator oil (96) for the scroll compressor (10) after assembled.
In a third setup step shown in FIG. 14 , the fixed scroll (34) is placed on the housing (36) and the orbiting scroll (31) so that the fixed scroll wrap (35) and the orbiting scroll wrap (32) are meshed with each other, and the fixed scroll (34) is positioned in the X- and Y-axis directions temporarily with the use of the positioning pins (38a). Wherein, according to the relationship as described above between the pitch diameter and the clearance of the positioning pins (38a), the fixed scroll (34) is positioned in the θ direction sufficiently accurately, and accordingly, the positioning pins (38a) serve as final positioning means for positioning in the θ direction.
In a fourth setup step shown in FIG. 15 , the fixed scroll (34) is fastened to the housing (31) by means of the bolts (38b) with the positioning pins (38a) inserted in the positioning holes (34c, 36c) to fixed the fixed scroll (34) provisionally.
In a fifth setup step shown in FIG. 16 , the positioning pins (38a) are taken off. Thus, all the steps for setup are completed, and then, the assembly (11) is conveyed to a centering/assembling facility (the positioning apparatus (40)), as shown in FIG. 17 . In FIG. 17 , the centering/assembling facility (40) is simplified.
Steps for centering will be described next.
FIG. 18 shows the state where the assembly (11) is conveyed to the centering/assembling facility (40). Suppose that this state serves as a first centering step. In the first centering step, the assembly (11) is placed on the pedestal (46) together with the conveyance pallet (95) with the housing (36) located up (the conveyance pallet (95) is omitted in FIG. 3 and FIG. 7 ), and various members are on standby around the assembly (11), such as the pressing mechanism (56), the cramp mechanism (63), the striking units (70), the rotary encoder (53) and the coupling (55), the position detection mechanisms (65), and the phase detection mechanism (90). A nut runner (97), the feeder connector (42), and the like (not shown in FIG. 3 ) are on standby therearound in addition. The drawings following FIG. 18 show operation images of the respective steps and have no difference in function from FIG. 3 and FIG. 7 though detailed specific structures of the cramp mechanism (63), the striking units (70), and the like are slightly different from those in FIG. 3 and FIG. 7 . Therefore, the operation will be described below with reference to the images.
In the state that the assembly (11) is placed on the pedestal (46), the lower end of the body member (16) (or the conveyance pallet (95)) is fitted inside the guide member (50) so as to position the lower end face of the crank shaft (20) above the through hole (52) and so as to allow the oil pickup (20a) to protrude downward from the through hole (52), as shown in FIG. 3 and FIG. 7 .
In a second centering step shown in FIG. 19 , the cramp head (64) of the cramp mechanism (63) is allowed to push the outer peripheral face of the main body (16) of the assembly (11) to fix the assembly (11) from the surrounding thereof, and the feeder terminal (19) is connected to the feeder connecter (42). The rotating shaft (53a) of the rotary encoder (53) is connected to the oil pickup (20a) of the crank shaft (20) by means of the coupling (55), and the air cylinder (57) of the pressing mechanism (56) is operated to press the fixed scroll (34) to the housing (36) of the assembly (11).
In a third centering step shown in FIG. 20 , the nut runner (97) is lowered to loosen the bolts (38b). Because, with the bolts (38b) fastened, the striking units (70) cannot move the fixed scroll (34) (for position adjustment) thereafter.
After the bolts (38b) are loosened, a fourth centering step shown in FIG. 21 is performed. In the fourth step, the nut runner (97) is raised, and the laser displacement gauge (91) of the phase detection mechanism (90) advances. In this time point, the sensor (92) of the laser displacement gauge (91) is located above the notches (34b) of the fixed scroll (34) (see FIG. 9 ).
Then, in a fifth centering step shown in FIG. 22 , the driver (82) shown in FIG. 7 allows the compressor motor (25) to be conducted through the inverter (81) to cause the crank shaft (20) to rotate at a constant low rotation speed, for example, approximately four rotations per one second, and the laser displacement gauge (91) detects the outer peripheral protrusions (31b) of the orbiting scroll (31) through the notches (34b) of the fixed scroll (34). Then, the driver (82) detects the phase of the crank shaft (20), that is, the phase of the orbiting scroll (31) on the basis of the position of the outer peripheral protrusions (31b) and the rotation position signal of the rotary encoder (53).
When detection of the phase of the orbiting scroll (31) is finished, a sixth centering step shown in FIG. 23 is performed. In the sixth step, the laser displacement gauge (91) of the phase detection mechanism (90) is retreated while the striking units (70) are allowed to advance. Further, the electric micrometers (66) on the X-axis and the Y-axis, which serve as the position detection mechanisms (65), are allowed to advance for detection of the location of the fixed scroll (34).
In a next seventh centering step shown in FIG. 24 , the striking units (70) moves and positions the fixed scroll (34) while the crank shaft (20) and the orbiting scroll (31) are rotated by the compressor motor (25). To do so, a first centering operation, a second centering operation, and a third centering operation are performed in this order, wherein: the first centering operation is performed in such a way that each end of the movable range in the X-axis direction of the fixed scroll (34) is once detected and the fixed scroll (34) is positioned at the center therebetween; the second centering operation is performed in such a way that each end of the movable range of the fixed scroll (34) in the Y-axis direction is detected next and the fixed scroll (34) is positioned at the center therebetween; and the third centering operation is performed in such a way that each end of the movable range of the fixed scroll (34) in the X-axis direction is detected again and the fixed scroll (34) is positioned at the center therebetween.
In each of the above centering operations, the phase or the rotation angle of the fixed scroll (34) has been detected, and accordingly, the fixed scroll (34) at a predetermined part thereof (where the fixed scroll wrap (35) is close to or in contact with the orbiting scroll wrap (32)) is moved in the minus direction (or the plus direction) on the X-axis first on the basis of the detected phase so that the outer peripheral face of the fixed scroll wrap (35) separates from the inner peripheral face of the orbiting scroll wrap (32). As shown in FIG. 25 , when the right striking unit (70) is operated in the state where the orbiting scroll (31) is located at the end in the plus direction on the X-axis (right end in the drawing), the impact force exceeds the frictional force to invite rotation of the fixed scroll (34) even under restriction of the rotation of the fixed scroll (34) by the pressing mechanism (56), thereby inviting poor positioning accuracy. The above operation is performed for preventing this phenomenon.
In view of the foregoing, in the present embodiment, the right striking unit (70) in the drawing is operated when the orbiting scroll (31) is located at the end in the minus direction on the X-axis (left end in the drawing), as shown in FIG. 26 . Then, whether or not the fixed scroll (34) shifts upon inversion of the orbiting scroll (31) is judged. Unless shift of the fixed scroll (34) is detected, which means that the wraps (32, 35) are out of contact with each other yet, striking of the fixed scroll (34) and the inversion of the orbiting scroll (31) are repeated. On the other hand, upon detection of shift of the fixed scroll (34), which means that the wraps (32, 35) are in contact with each other, the point of the predetermined part is judged as one end of a movable range of the fixed scroll (34). The same operation is performed in the plus direction (or the minus direction) on the X-axis to detect the other end of the movable range of the fixed scroll (34). In this way, the contact position of the fixed scroll (34) is detected at each two (plural) points in the respective minus directions and the respective plus directions on the X-axis and the Y-axis, and the fixed scroll (34) is positioned at the respective centers.
Details of the first to third centering operations are as follows.
First in the first centering operation, movement of the fixed scroll (34) in the minus direction on the X-axis and inversion of the orbiting scroll (31) are repeated to set, as a first contact point in the X-axis direction, the point where contact between the fixed scroll wrap (35) and the orbiting scroll wrap (32) is detected, and then, movement of the fixed scroll (34) in the plus direction on the X-axis and inversion of the orbiting scroll (31) are repeated to set, as a second contact point in the X-axis direction, the point where contact between the fixed scroll wrap (35) and the orbiting scroll wrap (32) is detected. Accordingly, the center between the first contact point and the second contact point is set as the center in the X-axis direction.
Referring to the second centering operation, movement of the fixed scroll (34) in the minus direction on the Y-axis and inversion of the orbiting scroll (31) are repeated to set, as a first contact point in the Y-axis direction, the point where contact between the fixed scroll wrap (35) and the orbiting scroll wrap (32) is detected, and then, movement of the fixed scroll (34) in the plus direction on the Y-axis and inversion of the orbiting scroll (31) are repeated to set, as a second contact point in the Y-axis direction, the point where contact between the fixed scroll wrap (35) and the orbiting scroll wrap (32) is detected. Accordingly, the center between the first contact point and the second contact point is set as the center in the Y-axis direction.
Further, in the third centering operation, movement of the fixed scroll (34) in the minus direction on the X-axis and inversion of the orbiting scroll (31) are repeated to set, as a first contact point in the X-axis direction, the point where contact between the fixed scroll wrap (35) and the orbiting scroll wrap (32) is detected, and then, movement of the fixed scroll (34) in the plus direction on the X-axis and inversion of the orbiting scroll (31) are repeated to set, as a second contact point in the X-axis direction, the point where contact between the fixed scroll wrap (35) and the orbiting scroll wrap (32) is detected. Accordingly, the center between the first contact point and the second contact point is set as the center in the X-axis direction.
As described above, in the seventh centering step, after each end of the respective movable ranges in the X-axis direction and the Y-axis direction of the fixed scroll (34) is detected, the fixed scroll (34) is positioned at the respective centers of the movable ranges. Through the first to third centering operations, the center of the fixed scroll (31) can be obtained to lead to positioning of the fixed scroll (34).
During the time when the fixed scroll (34) is moved by the striking units (70) in the seventh centering step, the direction in which the fixed scroll (34) is to be moved is restricted to the X-axis direction and the Y-axis direction by the guide (41) of the pressing mechanism (56), and the impact force is applied in the direction in which the wraps (32, 35) separate from each other in the predetermined part of the fixed scroll (34) (where the fixed scroll wrap (35) is closed to or in contact with the orbiting scroll wrap (32)). Accordingly, the fixed scroll (34) is moved in parallel without being rotated.
After the fixed scroll (34) is positioned, an eighth centering step shown in FIG. 27 is performed. In the eighth centering step, the conduction to the compressor motor (25) is stopped first to stop each rotation of the crank shaft (20) and the orbiting scroll (34). Then, the striking units (70) and the electric micrometers (66) are retreated, and the nut runner (97) is lowered to fasten the bolts (38b), thereby fastening the fixed scroll (34) to the housing (36). At the fastening, the fixed scroll (34) is positioned accurately.
Thereafter, the routine proceeds to a ninth centering step shown in FIG. 28 . In the ninth centering step, the nut runner (97) is raised, and the rod (57a) of the air cylinder (57) is retreated to raise the pressing member (58) of the pressing mechanism (56). Further, the rotary encoder (53) and the coupling (55) are integrally lowered to be taken off from the oil pickup (20a) of the crank shaft (20). The cramp mechanism (63) is retreated, and the feeder connector (42) is retreated to be taken off from the feeder terminal (19).
Whereby, all the steps for positioning the fixed scroll (34) are completed. Then, as shown in FIG. 29 , a work conveying step is performed for conveying the assembly (11) out from the positioning apparatus (40) as the centering/assembling facility.

-Effects of Embodiment-

In the present embodiment, in positioning the fixed scroll (34) in such a manner that the fixed scroll (34) is placed on the housing member (36) of the assembly (11) so that the wraps (32, 35) are meshed with each other and the fixed scroll (34) is moved by the moving mechanism (75) on the basis of the contact state of the wraps (32, 35), the phase detection mechanism (90) detects the to-be-detected parts (31b) of the orbiting scroll (31) through the notch (34b) of the fixed scroll (34), so that the apparatus can recognize the phase of the orbiting scroll (31) accurately. Since the fixed scroll (34) can be positioned with the phase of the orbiting scroll (31) recognized accurately, influence of assembling error is obviated dislike the conventional one in which positioning is performed after phase detection, thereby achieving accurate phase detection and positioning. Further, phase detection can be performed while positioning is performed, thereby preventing the assembling process from being complicated.
In the present embodiment, the apparatus can recognize the phase of the orbiting scroll (31) all the time during rotation of the crank shaft (20) on the basis of the position of the to-be-detected part (31b) of the orbiting scroll (31) detected by the sensor (92) of the phase detection mechanism (90) and the rotation position signal of the rotary encoder (53). Since the fixed scroll (34) can be positioned with the phase of the orbiting scroll (31) recognized more accurately, the positioning accuracy increases.
Further, in the present embodiment, the striking unit (70) applies the impact force to the fixed scroll (34) with the fixed scroll (34) pressed to the housing member (36). This moves the fixed scroll (34) by a minute distance to achieve precise positioning of the fixed scroll (34).
Still further, in the present embodiment, the X-axis direction and the Y-axis direction in which the guide (41) allows the fixed scroll (34) to be moved agree with the directions of the impact force that the moving mechanism (75) applies to the fixed scroll (34). Accordingly, the fixed scroll (34) can be positioned by parallel movement thereof without rotation. Hence, the positioning accuracy increases further.
In addition, in the present embodiment, in the internal space of the casing (15), the space on the side of the notch (34b) of the fixed scroll (34) serves as the low-pressure space filled with the low-pressure gas. In the scroll compressor, the outer peripheral side of the spiral is low in pressure, and therefore, high-pressure gas may be introduced into the spiral through the notch (34b) in operation if the space in the casing (15) serves as a high-pressure space. In contrast, in the present embodiment, since the space is set as the low-pressure space (S1), such a problem is obviated during operation. Hence, the scroll fluid machinery (10) can function normally as a product with the notch (34b) remaining in the fixed scroll (34). The same is applied to the case where the embodiment is applied to an expansion engine. The space may serve as the high-pressure space if the notch (34b) is covered after positioning the fixed scroll (34).

The above embodiment may have any of the following aspects.
For example, in the above embodiment, the air cylinder (100) is used for advancing/retreating the head (74) of the striking units (70), but a crank mechanism or a cam mechanism may be used instead. The striking units (70) as means for moving the fixed scroll (34) may not necessarily include the piezoelectric elements (73), and another elements may be used, such as a moving mechanism (75) using a feeding mechanism by means of ball screws. In other words, the moving mechanism (75) may be any mechanism only if it can adjust the position of the fixed scroll (34).
Further, the fixed scroll (34) is positioned with the orbiting scroll (31) rotated in the above embodiment. The fixed scroll (34) may be positioned by striking of the fixed scroll (34) and inverting the orbiting scroll (31) in the X-axis direction and the Y-axis direction with the orbiting scroll (31) stopped at a predetermined position.
In addition, the laser displacement gauge (91) detects the phase of the orbiting scroll (31) through the notches (34b) of the orbiting scroll (31) after the fixed scroll (34) is mounted to the assembly (11). Alternatively, the phase detection mechanism (90), such as a laser displacement gauge may detect the eccentric portion (22) of the crank shaft (20) before the orbiting scroll (31) and the fixed scroll (34) are mounted to the assembly (11).
It should be noted that the above embodiments are essentially preferable examples and are not intended to limit the present invention, the applicable objects thereof, and the usable scope thereof.

Industrial Applicability

As described above, the present invention is useful for apparatuses for positioning a fixed scroll in assembling a scroll fluid machinery.

Claims

An apparatus for positioning a fixed scroll (34), suitable for use in a process for assembling a scroll fluid machinery (10) forming part of the apparatus, on the basis of a positional relationship between a wrap (35) of the fixed scroll (34) and a wrap (32) of an orbiting scroll (31), the apparatus comprising:
an assembly (11) which is an integrated combination of the orbiting scroll (31), a crank shaft (20) engaged with the orbiting scroll (31), and a housing member (36) forming a bearing for the crank shaft (20);

a fixing member (63) fixing the assembly (11);

the fixed scroll (34);

a moving mechanism (75) moving the fixed scroll (34) meshed with the orbiting scroll (31); and

control means (80) configured to control the moving mechanism (75) on the basis of a contact state of the wrap (35) of the fixed scroll (34) and the wrap (32) of the orbiting scroll (31) to position the fixed scroll (34), the apparatus being characterised by

a phase detection mechanism (90) detecting a phase or a rotation angle of the orbiting scroll (31);

wherein a to-be-detected part (31b) for phase detection is formed at the orbiting scroll (31) while a notch (34b) allowing the to-be-detected part (31b) to be observed from outside is formed in the fixed scroll, and

the phase detection mechanism (90) includes a sensor (92) movable to a point facing the notch (34b) wherein the phase detection is mechanism (90) is configured to detect the phase of the orbiting scroll (31) on the basis of a change in a position of the to-be-detected part (31b) of the orbiting scroll (31) which is accompanied by rotation of the crank shaft (20).
The apparatus of Claim 1,
wherein the phase detection mechanism (90) includes a rotary encoder (53) connected to the crank shaft (20) and is configured to detect the phase of the orbiting scroll (31) all the time during rotation of the crank shaft (20) on the basis of a position of the to-be-detected part (31b) of the orbiting scroll (31) which is detected by the sensor (92) and a rotation position signal of the rotary encoder (53).
The apparatus of Claim 1,
wherein the moving mechanism (75) includes a striking unit (70) moving the fixed scroll (34) by applying impact force to the fixed scroll (34) under a state that the fixed scroll (34) is pressed to the housing member (36).
The apparatus of Claim 3, further comprising:
a guide (41) allowing the fixed scroll (34) to move in parallel to an X-axis direction and a Y-axis direction, which are intersected at a right angle with each other, with posture of the fixed scroll (34) unchanged,

wherein the X-axis direction and the Y-axis direction in which the guide (41) allows the fixed scroll (34) to move agree with directions of the impact force that the moving mechanism (75) applies to the fixed scroll (34).
The apparatus of Claim 1,
wherein the to-be-detected part (31b) is formed at an outer peripheral part of the orbiting scroll (31) while the notch (34b) is formed in an outer peripheral part of the fixed scroll (34), and
in an internal space of the casing (15) that the scroll fluid machinery (10) includes, an entirety of the inner space or at least a space on a side of the notch (64b) of the fixed scroll (34) serves as a low-pressure space filled with low-pressure gas.