Patent Application
20170239785
The present invention relates to a method and device for manufacturing a scroll for a compressor, a compressor scroll, and a scroll compressor.
Conventional scroll compressors include a fixed scroll with a spiral-shaped wall portion provided on a first side of an end plate and an orbiting scroll with a wall portion on a first side of an end plate with essentially the same spiral shape as that of the wall portion of the fixed scroll. The first sides of the end plates of the fixed scroll and the orbiting scroll are brought to face one another to assembly the wall portions together. In this mated state, the orbiting scroll orbits about the fixed scroll to gradually reduce the volume of the compression chamber formed between the wall portions and compress the fluid in the compression chamber.
An example of a conventional scroll for a compressor is described in the method of manufacturing a scroll compressor of Patent Document 1. In Patent Document 1, a fixed scroll and/or an orbiting scroll is rendered with a plurality of minute recesses on the side (wrap side) opposite the end plate (end cover) by being jetted with a fluid containing abrasive particles. This is to help with the retention of lubricating oil on the surface.
Additionally, for example, in the method of enhancing residual stress of a metallic material described in Patent Document 2, to prevent stress corrosion cracking at a weld portion of the metallic material and nearby, a fluid flow containing cavitation bubbles is impinged on the surface of the metallic material, the cavitation bubbles being generated by cavitation via water jet. The impact force generated by the collapse of the cavitation bubbles imparts compressive residual stress to the metallic material.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-074540A
Patent Document 2: Japanese Patent No. 3162104B
Scrolls for compressors experience a concentration of stress at the corner portion where the end plate and the wall portion are joined when in operation. Such fatigue is likely to cause cracks. Accordingly, it is desirable to enhance the fatigue strength by imparting compressive residual stress to the target region particularly vulnerable to fatigue-generated cracks. Methods of imparting such residual stress include peening. However, in typical shot peening methods, the steels balls used for peening may not hit the target region. Thus, such methods are not suitable for application to scrolls. A method in which cavitation bubbles generated by a water jet are used is more suitable for application to scrolls than shot peening methods because these cavitation bubbles tend to reach smaller regions such as the target region described above.
However, while the application of cavitation bubbles generated by a water jet can be considered suitable, scrolls have a shape different from the plate-like shape of the workpiece in Patent Document 2 in that a wall portion is provided on an end plate. Such a shape can make it difficult for the cavitation bubbles to impinge on the target region to impart compressive residual stress thereto.
To solve the problems described above, the present invention provides a method and device for manufacturing a compressor scroll capable of appropriately impinging cavitation bubbles on a target region of the scroll, and a compressor scroll and a scroll compressor resistant to cracks.
To achieve the object described above, an embodiment of the present invention is a method for manufacturing a compressor scroll, the compressor scroll including a first scroll provided on a spiral-shaped first wall portion disposed on a first side of a first end plate, a second scroll provided on a spiral-shaped second wall portion disposed on a first side of a second end plate, with the second wall portion meshed with the first wall portion of the first scroll, wherein the second scroll is supported for orbiting movement and prevented from rotating, a step portion disposed on the first side of each of the end plates where a height transitions from high on a center portion side of the spiral following the respective wall portion to low on an outer end side, and a stepped portion disposed on each of the wall portions where a height transitions from low on the central portion side of the spiral to high on the outer end side, wherein the stepped portions engage with the corresponding step portions, the method comprising the step of water jet peening by jetting cavitation bubbles generated underwater by a water jet at the first side of the end plate of at least one of the scrolls, with a center of the cavitation bubbles being offset from a center of the spiral shape of the wall portion on the end plate and the step portion and the stepped portion positioned at an outer peripheral portion of the cavitation bubbles.
According to this method for manufacturing a compressor scroll, the center of the cavitation bubbles is offset from the center of the spiral shape of the wall portion on the end plate. When the step portion and the stepped portion are positioned at the outer peripheral portion of the range of the cavitation bubbles, the position of the center of the cavitation bubbles becomes positions where corner portions of the wall portion near the step portion and the stepped portion are positioned on a straight line through the spiral-shaped channel of the wall portion. This allows the flow of fluid flow containing the cavitation bubbles to not be obstructed by the wall portion, and thus allow the cavitation bubbles to impinge on the corner portions. In other words, the cavitation bubbles can be appropriately impinged on target regions of the scroll, imparting compressive residual stress to the target regions to prevent cracks.
In a method for manufacturing a compressor scroll according to another embodiment of the present invention, the water jet peening step includes moving the cavitation bubbles and the scroll relative to one another to intersect with a straight imaginary line that joins the step portion and the stepped portion and the positions of the cavitation bubbles and the scroll.
According to this method for manufacturing a compressor scroll, the cavitation bubbles can be appropriately impinged on the target regions (the corner portions) of the scroll, imparting compressive residual stress to the target regions to prevent cracks.
In a method for manufacturing a compressor scroll according to another embodiment of the present invention, the water jet peening step includes stopping the movement of the cavitation bubbles and the scroll relative to one another for a predetermined period of time at the positions of the cavitation bubbles and the scroll.
According to this method for manufacturing a compressor scroll, the cavitation bubbles can be sufficiently impinged on the target regions (the corner portions) of the scroll, imparting compressive residual stress to the target regions to prevent cracks.
In a method for manufacturing a compressor scroll according to another embodiment of the present invention, the water jet peening step is performed before surface treatment of the scroll.
According to this method for manufacturing a compressor scroll, the water jet peening step is performed before the surface treatment of the scroll. This facilitates imparting compressive residual stress via impingement of the cavitation bubbles to obtain a significant effect of preventing cracks.
In a method for manufacturing a compressor scroll according to another embodiment of the present invention, a cleaning fluid is mixed in with the water where the cavitation bubbles are generated.
According to this method for manufacturing a compressor scroll, the scroll can be cleaned by the cleaning fluid at the same time as the water jet peening step.
To achieve the object described above, an embodiment of the present invention is a device for manufacturing a compressor scroll, the compressor scroll including a first scroll provided on a spiral-shaped first wall portion disposed on a first side of a first end plate, a second scroll provided on a spiral-shaped second wall portion disposed on a first side of a second end plate with the second wall portion meshed with the first wall portion of the first scroll, wherein the second scroll is supported for orbiting movement and prevented from rotating, a step portion disposed on the first side of each of the end plates where, following the respective wall portion, a height transitions from high on a center portion side of the spiral to low on an outer end side, and a stepped portion disposed on each of the wall portions where a height transitions from low on the central portion side of the spiral to high on the outer end side, wherein the stepped portions engage with the corresponding step portions, the device comprising a vessel containing water; a positioning unit that positions at least one of the scrolls in the vessel; a water jet jetting disposed underwater in the vessel that includes a nozzle that jets a water jet at the scroll; wherein cavitation bubbles generated underwater in the vessel by the water jet of the water jet jetting unit are jet at the first side of the scroll, with a center of the cavitation bubbles being offset from a center of the spiral shape of the wall portion on the end plate and the step portion and the stepped portion positioned at an outer peripheral portion of the cavitation bubbles.
According to this device for manufacturing a compressor scroll, the water jet peening step described above in the method for manufacturing a compressor scroll can be performed.
In a device for manufacturing a compressor scroll according to another embodiment of the present invention, the positioning unit includes a fixing mechanism that engages with the end plate of the scroll to fix the scroll.
According to this device for manufacturing a compressor scroll, by fixing the scroll via this fixing mechanism, the scroll can be supported in place when the cavitation bubbles impinge on the scroll, allowing the cavitation bubbles to be appropriately impinged on the target regions (the corner portions) to impart compressive residual stress to the target regions and prevent cracks.
In a device for manufacturing a compressor scroll according to another embodiment of the present invention, the positioning unit includes a movement mechanism that moves the scroll to intersect with a straight imaginary line that joins the step portion and the stepped portion and the positions of the cavitation bubbles and the scroll.
According to this device for manufacturing a compressor scroll, the cavitation bubbles can be appropriately impinged on the target regions (the corner portions) of the scroll, imparting compressive residual stress to the target regions to prevent cracks.
In a device for manufacturing a compressor scroll according to another embodiment of the present invention, the movement mechanism includes a plurality of fixing mechanisms to move a plurality of the scrolls.
According to this device for manufacturing a compressor scroll, the cavitation bubbles can be appropriately impinged in order to target regions (the corner portions) of a plurality of scrolls. As a result, the water jet peening step of the method for manufacturing a compressor scroll described above can be efficiently performed.
In a device for manufacturing a compressor scroll according to another embodiment of the present invention, the water jet jetting unit includes a pivot mechanism that pivots the nozzle so that the cavitation bubbles are pivoted with respect to the scroll.
According to this device for manufacturing a compressor scroll, the cavitation bubbles can directly impinge on the target regions (the corner portions), which are internal angle portion of the end plate and the wall portion. Thus, the cavitation bubbles can be sufficiently impinged on the target regions of the scroll.
To achieve the object described above, an embodiment of the present invention is a compressor scroll made using the device for manufacturing a compressor scroll described above.
According to this compressor scroll, cracks can be prevented, and accidents caused by cracks can be reduced.
To achieve the object described above, an embodiment of the present invention is a scroll compressor, comprising the compressor scroll described above.
According to this scroll compressor, cracks can be prevented, and accidents caused by cracks can be reduced.
According to the present invention, cavitation bubbles can be appropriately impinged on target regions of a scroll.
Embodiments according to the present invention will be described below on the basis of the drawings. Note that the present invention is not limited by these embodiments. In addition, the constituent elements in the embodiments described below include those that can be easily replaced by a person skilled in the art or those that are substantially the same.
A scroll compressor 10 illustrated in
The housing 11 composes a housing main body 11A and a cover 11B. The housing main body 11A is hollow and includes an integrated tubular large diameter portion 11Aa and small diameter portion 11Ab. An opening end of the housing main body 11A on the side where the large diameter portion 11Aa is located is mated and closed with the cover 11B fixed via a plurality of bolts 20. A drive shaft 14 is inserted in the housing main body 11A on the side where the small diameter portion 11Ab is located and a shaft seal 11D seals the space between the drive shaft 14 and the housing main body 11A. In such a manner, the housing 11 is configured as a sealed container that encloses the entire scroll compressor.
The fixed scroll 12, as illustrated in
The fixed scroll 12, as illustrated in
The orbiting scroll 13 is similar to the fixed scroll 12 and, as illustrated in
The orbiting scroll 13 is also similar to the fixed scroll 12 in that, as illustrated in
The fixed scroll 12 and the orbiting scroll 13, as illustrated in
As illustrated in
Additionally, a second side of the end plate 13A of the orbiting scroll 13 is in contact with a wall 11Ad, which is where the large diameter portion 11Aa and the small diameter portion 11Ab inside the housing main body 11A meet. This restricts movement of the orbiting scroll 13 in the axial direction, which is the extending direction of the drive shaft 14.
The drive shaft 14, as described above, is inserted in the small diameter portion 11Ab of the housing main body 11A. The drive shaft 14 is able to freely rotate with a first end portion 14A of the drive shaft 14 being supported inside the small diameter portion 11Ab by a bearing 22, a large diameter disk portion 14B disposed in a central portion being supported by a bearing 23, as illustrated in
The eccentric shaft 14C mates with a balance bushing 24 disposed on the outer periphery thereof. The balance bushing 24 moves in an orbiting manner integrally with the eccentric shaft 14C. The balance bushing 24 is integrally provided with a balance weight 24A to offset the amount of unbalance caused by the orbiting scroll 13. The portion that mates with the eccentric shaft 14C of the balance bushing 24 is cylindrical, and an annular drive bushing 25 is mounted on the outer peripheral portion thereof.
The orbiting scroll 13 is provided with a protruding boss 13C in the central portion on the other side of the end plate 13A. The boss 13C is provided with a circular recessed portion 13D with a center corresponding to the position of the center of the spiral shape of the wall portion 12B. The drive bushing 25 is inserted in the recessed portion 13D of the orbiting scroll 13, the two being able to rotate relative to one another via a bearing 26. The orbiting scroll 13 is provided with a circular rotation-restricting recessed portion 13E on the outer peripheral portion on the other side of the end plate 13A. A plurality of the rotation-restricting recessed portions 13E are provided about the recessed portion 13D. A rotation stopping pin 11Ae that is fixed to the housing main body 11A is inserted in each of the rotation-restricting recessed portions 13E. By inserting the rotation stopping pins 11Ae in the rotation-restricting recessed portion 13E, the rotation of the orbiting scroll 13 is prevented.
The drive shaft 14 is driven in rotation by a drive unit 15. The drive unit 15 includes a pulley 15A supported for free rotation by a bearing 27 mounted on the outer peripheral portion of the small diameter portion 11Ab of the housing main body 11A. The drive unit 15 includes a rotation plate 15B fixed to the first end portion 14A of the drive shaft 14 by a nut 28. The rotation plate 15B is coupled to a support ring 15C on the outer peripheral portion thereof. An end surface of the pulley 15A is fixed to the support ring 15C. An electromagnetic clutch 15D is provided inside the pulley 15A. The pulley 15A transmits torque from the driving source (engine, for example) via a drive belt (not illustrated).
In the scroll compressor 10 configured as such, when the electromagnetic clutch 15D is disengaged, the driving source torque is transmitted to the pulley 15A of the drive unit 15 and the drive shaft 14 rotates. The rotation of the drive shaft 14 rotates the eccentric shaft 14C in an eccentric manner. The rotation of the eccentric shaft 14C is transmitted to the orbiting scroll 13 via the balance bushing 24 and the drive bushing 25. The orbiting scroll 13 orbits with its rotation prevented via the engagement of the rotation-restricting recessed portion 13E and the rotation stopping pin 11Ae. The refrigerant gas taken in to the suction chamber S3 inside the housing 11 from the suction port 11Ac is taken into the compression chamber S1 by this movement. Then, as the orbiting scroll 13 continues to orbit, the compression chamber S1 becomes gradually narrower towards the center of the scrolls 12, 13 and the volume decreases. Inside the compression chamber S1, the refrigerant gas is compressed and it flows toward the central portion of the scrolls 12, 13 until reaching the discharge port 12C. The discharge valve 12D opens or closes depending on the difference in pressure between the compression chamber S1 and the discharge chamber S2. In other words, the refrigerant gas is compressed in the compression chamber S1 and when the compression chamber S1 has a higher pressure than the discharge chamber S2, the refrigerant gas pushes open the discharge valve 12D and flows into the discharge chamber S2. Thereafter, the high pressure refrigerant gas is discharged from the discharge chamber S2 through a discharge port (not illustrated) provided on the cover 11B and outside of the housing 11 and introduced into an air conditioner mounted in a vehicle.
A method and device for manufacturing a compressor scroll according to the present embodiment will be described below.
In a method and device for manufacturing the compressor scroll according to the present embodiment, to enhance crack resistance at a corner portion of the end plate 13A and the wall portion 13B of the scroll 13, a fluid flow containing cavitation bubbles generated underwater via cavitation by a water jet is impinged on the corner portion. The impact force generated by the collapse of the cavitation bubbles imparts compressive residual stress to the metallic material.
Here, target regions for compressive residual stress, which are crack-prone regions, are corner portion A and corner portion B as illustrated in
Here, in the method for manufacturing a compressor scroll according to the present embodiment, as illustrated in
For example, if the center P of the cavitation bubbles C is located at the center O of the spiral shape of the wall portion 13B on the end plate 13A, because the corner portions A, B are not positioned on a straight line through the spiral-shaped channel of the wall portion 13B, the flow of the fluid flow containing the cavitation bubbles C is inhibited and interrupted by the wall portion 13B, thus making it difficult for the cavitation bubbles C to impinge on the corner portions A, B.
Alternatively, according to a method for manufacturing a compressor scroll according to the present embodiment, as described above, the center P of the cavitation bubbles C is offset from the center O of the spiral shape of the wall portion 13B on the end plate 13A. When the step portion 13Aa and the stepped portion 13Ba are positioned at the outer peripheral portion of the range of the cavitation bubbles C, the position of the center P of the cavitation bubbles C becomes positions P1, P2, or P3 where the corner portions A, B of the wall portion 13B near the step portion 13Aa and the stepped portion 13Ba are positioned on a straight line through the spiral-shaped channel of the wall portion 13B. This allows the flow of fluid flow containing the cavitation bubbles C to not be obstructed by the wall portion 13B, and thus allow the cavitation bubbles C to impinge on the corner portions A, B. In other words, the cavitation bubbles C can be appropriately impinged on target regions of the scroll 13, imparting compressive residual stress to the target regions to prevent cracks.
Additionally, a method for manufacturing a compressor scroll according to the present embodiment, as illustrated in
According to this method for manufacturing a compressor scroll, the cavitation bubbles C can be appropriately impinged on the target regions (the corner portions A, B) of the scroll 13, imparting compressive residual stress to the target regions to prevent cracks.
Additionally, a water jet peening step of a method for manufacturing a compressor scroll according to the present embodiment may include stopping the movement of the cavitation bubbles C and/or the scroll 13 for a predetermined period of time at the positions P1, P2, P3 of the cavitation bubbles C and the scroll 13.
According to this method for manufacturing a compressor scroll, the cavitation bubbles C can be sufficiently impinged on the target regions (the corner portions A, B) of the scroll 13, imparting compressive residual stress to the target regions to prevent cracks. Note that “predetermined period of time” refers to a period of time necessary for a target regions to be imparted with compressive residual stress.
Additionally, in a method for manufacturing a compressor scroll according to the present embodiment, a water jet peening step is performed before the surface treatment of the scroll 13.
Surface treatment may be alumite treatment in which the surface is coated with alumite to enhance the corrosion resistance and abrasion resistance in case where the scroll 13 is made of an aluminum alloy. By performing surface treatment, the compressive residual stress imparted via impingement of the cavitation bubbles C may be suppressed and thus the effect of preventing cracks may be reduced. Thus, according to this method for manufacturing a compressor scroll, the water jet peening step is performed before the surface treatment of the scroll 13. This facilitates imparting compressive residual stress via impingement of the cavitation bubbles C to obtain a significant effect of preventing cracks.
Additionally, in a method for manufacturing a compressor scroll according to the present embodiment, a cleaning fluid is mixed in with the water where the cavitation bubbles C are generated.
According to this method for manufacturing a compressor scroll, the scroll 13 can be cleaned by the cleaning fluid at the same time as the water jet peening step.
A device for manufacturing a compressor scroll used in the method for manufacturing a compressor scroll described above will be explained below.
A device 1 for manufacturing a compressor scroll according to the present embodiment, as illustrated in
The vessel 2 has a water depth sufficient for the water jet peening step to be performed, in which cavitation bubbles C generated by the water jet J jetted from the nozzle 4A are impinged on the scroll 13 positioned by the positioning unit 3.
The positioning unit 3 is capable of positioning the scroll 13 inside the vessel 2 in a manner so that the water jet peening can be performed. The positioning unit 3, for example, includes a contact portion 3A that comes into contact with the second side of the end plate 13A of the scroll 13, and a chuck portion 3B that engages at a plurality of positions (three for example) around the periphery of the end plate 13A of the scroll 13.
The water jet jetting unit 4 includes the nozzle 4A, a nozzle support portion 4B that supports the nozzle 4A, and a high-pressure water pump 4C that supplies high-pressure water to the nozzle 4A.
The device for manufacturing a compressor scroll jets cavitation bubbles C generated underwater in the vessel 2 by the water jet J of the water jet jetting unit 4 at the first side of the scroll 13 positioned by the positioning unit 3, and as illustrated in
According to such a device 1 for manufacturing a compressor scroll, the water jet peening step described above in the method for manufacturing a compressor scroll can be performed.
Additionally, in the device 1 for manufacturing a compressor scroll according to the present embodiment, the positioning unit 3 includes the contact portion 3A and the chuck portion 3B which compose a fixing mechanism that fixes the scroll 13 by engaging with the end plate 13A of the scroll 13.
According to this device 1 for manufacturing a compressor scroll, by fixing the scroll 13 via this fixing mechanism, the scroll 13 can be supported in place when the cavitation bubbles C impinge on the scroll 13, allowing the cavitation bubbles C to be appropriately impinged on the target regions (the corner portions A, B) to impart compressive residual stress to the target regions and prevent cracks.
In the device 1 for manufacturing a compressor scroll of the present embodiment, the positioning unit 3, as illustrated in
The movement mechanism 3C is preferably a belt conveyor or other similar means for moving the fixing mechanism (the contact portion 3A and the chuck portion 3B) in a parallel manner while supported.
According to the device 1 for manufacturing a compressor scroll, the cavitation bubbles C can be appropriately impinged on the target regions (the corner portions A, B) of the scroll 13 to impart compressive residual stress to the target regions to prevent cracks.
In the device 1 for manufacturing a compressor scroll according to the present embodiment, the movement mechanism 3C includes a plurality of fixing mechanisms to move a plurality of scrolls 13.
According to this device 1 for manufacturing a compressor scroll, the cavitation bubbles C can be appropriately impinged in order on target regions (the corner portions A, B) of a plurality of scrolls 13. As a result, the water jet peening step of the method for manufacturing a compressor scroll described above can be efficiently performed.
In the device 1 for manufacturing a compressor scroll according to the present embodiment, the water jet jetting unit 4 includes a pivot mechanism 4D that pivots the nozzle 4A so that the cavitation bubbles C are pivoted with respect to the scroll 13.
The pivot mechanism 4D is provided on the nozzle support portion 4B and allows the jet direction of the water jet J from the nozzle 4A to be inclined with respect to a vertical line V illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-211938 | Oct 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/072426 | 8/6/2015 | WO | 00 |
