JP2009114943A - Scroll fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll fluid machine with proper back pressure acting to a movable scroll. <P>SOLUTION: The scroll fluid machine includes the movable scroll 30 disposed in a housing and capable of orbiting with respect to a fixed scroll, a boss 28 integrally formed on a back surface of an end plate 30a of the movable scroll 30, a drive shaft 16 having an end enclosed by the boss 28 via a bearing 26 and an inside flow path 16a opened to some part of the end to supply lubrication oil under high pressure to an inner area of the boss 28, and a seal ring 64 disposed in the inner area of the boss 28 and separating an opening of the inside flow path 16a and an outer area of the boss 28. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a scroll type fluid machine.

The scroll type fluid machine is used, for example, for compressing a refrigerant, and includes a movable scroll disposed in a housing so as to be rotatable with respect to a fixed scroll. The movable scroll forms a pressure chamber with the fixed scroll, and the pressure chamber performs a refrigerant suction, compression, and discharge process as the movable scroll rotates.
In order to turn the movable scroll, a boss is integrally formed on the rear surface of the end plate of the movable scroll. The boss surrounds the end of the drive shaft via a bearing, and the movable scroll is turned by the rotation of the drive shaft.

The drive shaft is formed with an internal flow path opened at an end surface thereof, and lubricating oil is supplied to the inside of the boss through the internal flow path. The pressure of the refrigerant discharged from the pressure chamber (discharge pressure) acts on the lubricating oil, and this lubricating oil not only lubricates the bearings, but also discharges the pressure against the back of the end plate of the movable scroll. It works (for example, refer to Patent Document 1).
However, an annular seal member is provided between the end plate of the movable scroll and the portion of the housing facing the end plate, and the discharge pressure acts as a back pressure in the end plate portion located inside the seal member. is there.
JP 2005-351098

In the conventional scroll type fluid machine, since the diameter of the seal member is large, the discharge pressure acts as a back pressure over a wide range on the back surface of the end plate of the movable scroll. For this reason, especially when compressing CO ₂ gas, the load acting to press the movable scroll against the fixed scroll becomes excessive, and smooth turning of the movable scroll may be hindered.
The present invention has been made based on the above-described circumstances, and an object thereof is to provide a scroll type fluid machine in which an appropriate back pressure acts on the movable scroll.

In order to achieve the above object, according to the present invention, a movable scroll disposed in a housing and capable of turning with respect to a fixed scroll, a boss integrally formed on a rear surface of a mirror plate of the movable scroll, and the boss A drive shaft having an internal flow path opened at any position of the end to supply lubricating oil at a high pressure to an end surrounded by a bearing and a region inside the boss; and A scroll type fluid machine is provided, comprising: a seal member disposed in an inner region and partitioning between an opening of the inner flow path and an outer region of the boss (Claim 1).
Preferably, the scroll type fluid machine further includes a communication groove that is formed on the outer surface of the drive shaft and communicates with each other the regions partitioned by the seal member.
Preferably, the scroll type fluid machine further includes an oil groove that is formed on an outer peripheral surface of the drive shaft and that vertically cuts a region of the outer peripheral surface of the drive shaft surrounded by the bearing.

Preferably, the scroll type fluid machine is used for compressing CO ₂ gas.

  In the scroll type fluid machine according to the first aspect of the present invention, since the seal member is disposed in the region inside the boss, the region where the high pressure acts by the lubricating oil is narrow on the back surface of the end plate of the movable scroll. For this reason, in the scroll type fluid machine, an appropriate load is applied to the movable scroll so as to be pressed toward the fixed scroll, and smooth turning of the movable scroll is ensured.

In addition, the seal member can be reduced in size by arranging the seal member in the region inside the boss.
In the scroll type fluid machine according to the second aspect, the lubricating oil is supplied to the outside of the boss through the communication groove. Thereby, the lubricating oil is smoothly supplied to the region outside the boss, and an appropriate pressure acts on the back surface of the end plate of the movable scroll.

In the scroll type fluid machine according to the third aspect, the lubricating oil is sufficiently supplied between the end portion of the drive shaft and the bearing through the oil groove, and the smooth turning of the movable scroll is ensured.
In the scroll type fluid machine according to the fourth aspect, even when the CO ₂ gas is compressed, an appropriate load is applied to the movable scroll so as to press the CO ₂ gas toward the fixed scroll, and smooth turning of the movable scroll is ensured.

FIG. 1 shows a scroll type fluid machine according to an embodiment of the present invention. This fluid machine is applied to, for example, a refrigeration system, an air conditioning system, or a hot water supply system, and compresses a refrigerant or the like as a working fluid.
This scroll type fluid machine includes a housing (closed container) 2. The housing 2 includes a cylindrical portion 4 and an upper lid 6 and a lower lid 8 that are airtightly fitted to the upper end and the lower end of the cylindrical portion 4, respectively. A suction pipe 10 for introducing a working fluid into the housing 2 is connected to the cylindrical portion 4, and a discharge pipe 12 for discharging the working fluid compressed in the housing 2 is connected to the upper lid 6. .

An electric motor 14 is accommodated in the cylindrical portion 4, and the electric motor 14 has a cylindrical stator 14a. The stator 14a is fixed to the cylindrical portion 4, and a columnar rotor 14b is concentrically disposed inside the stator 14a so as to be rotatable.
The rotor 14b is penetrated in the axial direction by the drive shaft 16, and the drive shaft 16 can rotate integrally with the rotor 14b. Accordingly, the drive shaft 16 is rotationally driven by energization of the electric motor 14.

The lower end of the drive shaft 16 reaches the central hole of the partition wall 18. A flanged sleeve 20 surrounding the lower end of the drive shaft 16 is fixed to the central hole of the partition wall 18, and a needle bearing 22 is inserted between the sleeve 20 and the drive shaft 16.
On the other hand, the upper end portion of the drive shaft 16 is formed in an eccentric bush 24, and the eccentric bush 24 is surrounded by a boss 28 via a slide bearing 26. The boss 28 is integrally formed on the back surface of the end plate (substrate) 30 a of the movable scroll 30.

The movable scroll 30 is pivotably disposed in a space formed between the upper block 32 and the lower block (center frame) 34, and the upper block 32 and the center frame 34 are fixed to the cylindrical portion 4 by welding. ing.
More specifically, a recess for receiving the end plate 30a of the movable scroll 30 is formed at the upper end of the center frame 34 so as to be pivotable, and an intermediate hole 38 for receiving the boss 28 is opened at the center of the bottom surface 36 of the recess. is doing. A shaft hole extends between the bottom surface of the intermediate hole 38 and the lower end of the center frame 34, and a plain bearing 40 is interposed between the shaft hole and the drive shaft 16.

A spiral wall 42 that meshes with the spiral wall 30 b of the movable scroll 30 is formed at the lower end of the upper block 32, and a pressure chamber 44 is formed between the upper block 32 and the movable scroll 30. That is, the upper block 32 has a function as a fixed scroll. For this reason, the upper block 32 is also referred to as a fixed scroll 32 below.
The end plate 30 a of the movable scroll 30 and the bottom surface 36 of the recess face each other with a predetermined gap in the axial direction of the drive shaft 16. A rotation prevention device for preventing rotation of 30 is provided. The rotation prevention device has, for example, a plurality of pins 46, and the base of each pin 46 is press-fitted into a pin hole opened on the back surface of the end plate 30a. The tip of each pin 46 is received in a bottomed hole 48 opened in the bottom surface 36 of the recess.

  As the movable scroll 30 turns, the position of the pressure chamber 44 moves from the radially outer side of the movable scroll 30 to the radially inner side along the spiral wall 30b, and the volume of the pressure chamber 44 decreases. That is, the pressure chamber 44 can compress the working fluid sucked in the radially outer side, and the fixed scroll 32 has the radially outer pressure chamber 44 and the suction pipe to supply the working fluid to the pressure chamber 44. A communication path (not shown) that connects the inner ends of 10 is formed.

A discharge hole 50 is formed in the fixed scroll 32, and the discharge hole 50 penetrates substantially the center of the fixed scroll 32 in the axial direction. The working fluid compressed in the pressure chamber 44 is discharged from the pressure chamber 44 through the discharge hole 50.
The discharge hole 50 is opened and closed by a reed valve as the discharge valve 52, and the discharge valve 52 is covered with a cover 54. The space in the cover 54 includes a downward flow path (not shown) for the working fluid and the lubricating oil contained in the working fluid formed in the fixed scroll 32, the center frame 34, and the rotor 14b, and a slot in the stator 14a. It is connected to the partition wall 18 through a gap therebetween. An ascending flow path for the working fluid reaching from the partition wall 18 to the upper lid 6, that is, the discharge pipe 12 is formed on the outer periphery of the stator 14 a, the center frame 34, and the fixed scroll 32.

The partition wall 18 partitions the inside of the housing 2 up and down, and an oil storage chamber 55 that stores lubricating oil is defined between the partition wall 18 and the lower lid 8. Lubricating oil introduction holes 18 a are formed in the partition wall 18, and the lubricating oil adhering to the upper surface of the partition wall 18 flows into the oil storage chamber 55 through the introducing holes 18 a.
An end plate 56 is also fixed to the partition wall 18 so as to close the lower end of the sleeve 20, and an outer rotor 58 a having inner teeth and an inner rotor 58 b having outer teeth are accommodated in a recess formed in the flange of the sleeve 20. Has been.

The outer rotor 58a is fixed to the outer peripheral surface of the recess, and the inner rotor 58b is fitted to the lower end of the drive shaft 16 so as to be integrally rotatable. That is, the sleeve 20, the end plate 56, the outer rotor 58 a, and the inner rotor 58 b constitute the trochoid pump 60, and the sleeve 20 and the end plate 56 constitute the casing of the trochoid pump 60.
The inlet of the trochoid pump 60 opened on the lower surface of the end plate 56 overlooks the oil storage chamber 55 and communicates with the vicinity of the bottom of the oil storage chamber 55 through a nozzle 62 fixed to the partition wall 18. On the other hand, the lower end surface of the drive shaft 16 faces the outlet of the trochoid pump 60 opened on the upper surface of the end plate 56.

The drive shaft 16 is formed with an internal flow path 16 a that passes through the drive shaft 16 in the axial direction, and an inlet of the internal flow path 16 a is open to a lower end surface of the drive shaft 16. For this reason, the internal flow path 16 a communicates with the outlet of the trochoid pump 60.
As shown in an enlarged manner in FIG. 2, the outlet of the internal flow path 16 a is opened at the upper end surface of the drive shaft 16. In addition, the exit of the internal flow path 16a should just open in the area | region inside the boss | hub 28. FIG.

An annular seal ring 64 is disposed as a seal member in a region inside the boss 28, and the seal ring 64 partitions a region between the outlet of the internal flow path 16 a and the region outside the boss 28.
More specifically, a circumferential groove 66 is formed on the inner peripheral surface on the tip side of the boss 28, and a radially outer portion of the seal ring 64 is fitted in the circumferential groove 66. The radially inner portion of the seal ring 64 is in sliding contact with the upper end of the drive shaft 16, that is, the outer peripheral surface of the eccentric bush 24, thereby sealing the gap between the boss 28 and the eccentric bush 24.

  However, as shown in FIG. 3, a spiral oil groove 68 is formed on the outer peripheral surface of the eccentric bush 24, and the oil groove 68 communicates the areas partitioned by the seal ring 64. The oil groove 68 extends from above the slide bearing 26 to below the seal ring 64 as viewed in the axial direction of the drive shaft 16, and vertically cuts the region of the eccentric bush 24 that is in sliding contact with the slide bearing 26. Yes.

In the scroll type fluid machine described above, when electric power is supplied to the electric motor 14, the rotor 14 b and the drive shaft 16 are rotationally driven, and the rotation of the drive shaft 16 is caused by the eccentric bush 24 and the slide bearing 26. Is converted into a swivel motion. While the movable scroll 30 is turning, the rotation of the movable scroll 30 is blocked by the rotation blocking device.
As the movable scroll 30 pivots with respect to the fixed scroll 32, the pressure chamber 44 sucks the working fluid including lubricating oil through the suction pipe 10, compresses the sucked working fluid, and passes through the discharge hole 50. A series of discharging processes is executed.

The working fluid containing the lubricating oil discharged from the pressure chamber 44 descends to the partition wall 18 through the descending flow path, and the lubricating oil collides with and adheres to the partition wall 18. Thus, the working fluid from which the lubricating oil is separated rises through the ascending flow path and is discharged through the discharge pipe 12.
The lubricating oil adhering to the partition wall 18 flows into the oil storage chamber 55 through the introduction hole 18a. Since the trochoid pump 60 operates as the drive shaft 16 rotates, the lubricating oil in the oil storage chamber 55 rises in the internal flow path 16a of the drive shaft 16 and flows out from the outlet of the internal flow path 16a.

The working fluid pressure (discharge pressure) discharged from the pressure chamber 44 acts on the lubricating oil in the oil storage chamber 55. For this reason, the pressure of the lubricating oil flowing out from the outlet of the internal flow path 16a is approximately equal to the discharge pressure and is high.
Here, since the seal ring 64 is disposed in the gap between the drive shaft 16 and the boss 28, the region where the discharge pressure acts as the back pressure on the back surface of the end plate 30 a of the movable scroll 30 is the inside of the boss 28. Limited to That is, in this scroll type fluid machine, a region inside the boss 28 is defined as a high pressure region.

  Since the lubricating oil leaks from the inside of the boss 28 to the outside through the oil groove 68, a certain amount of pressure (intermediate pressure) acts on the back surface of the end plate 30 a of the movable scroll 30 also on the outside of the boss 28. For this reason, the recess of the center frame 34 and the area outside the boss 28 in the intermediate hole 38 are defined as an intermediate pressure area. The leaked lubricating oil is used for lubrication of other sliding bearings 40 and sliding portions.

  In the scroll type fluid machine described above, since the seal ring 64 as a seal member is disposed in the region inside the boss 28, the region where the high pressure acts on the back surface of the end plate 30a of the movable scroll 30 is narrow. For this reason, in the scroll type fluid machine, an appropriate load acts on the movable scroll 30 so as to press the fixed scroll 32 toward the fixed scroll 32, and the smooth turning of the movable scroll 30 is ensured.

Further, since the seal ring 64 is disposed in the region inside the boss 28, the seal ring 64 can be reduced in size.
In the scroll type fluid machine described above, a part of the oil groove 68 forms a communication groove that communicates the areas partitioned by the seal ring 64, and the lubricating oil is supplied to the outside of the boss 28 through the communication groove. Is done. As a result, the lubricating oil is smoothly supplied to the region outside the boss 28, and an appropriate pressure acts on the back surface of the end plate 30 a of the movable scroll 30.

In the scroll type fluid machine described above, the lubricating oil is sufficiently supplied between the sliding bearing 26 and the eccentric bush 24 through the oil groove 68, and smooth turning of the movable scroll 30 is ensured.
The present invention is not limited to the above-described embodiment, and various modifications can be made.
For example, a circumferential groove for holding the seal ring may be formed in the eccentric bush 24 and the seal ring may be brought into sliding contact with the boss 28.

  Moreover, the sealing member should just be arrange | positioned in the area | region inside the boss | hub 28, and may surround the exit of the internal flow path 16a. For example, as shown in FIG. 4, a seal ring 70 may be disposed between the end surface of the drive shaft 16, that is, the end surface of the eccentric bush 24, and the back surface of the end plate 30 a of the movable scroll 30. In this case, as shown in FIGS. 5 and 6, in addition to the oil groove 68, a communication groove 72 is formed on the end face of the eccentric bush 24, and regions separated from each other by the seal ring 70 through the communication groove 72. Communicate.

In this case as well, a circumferential groove for holding the seal ring may be formed on either the end face of the eccentric bush 24 or the end plate 30a of the movable scroll 30.
The above-described scroll type fluid machine can be applied to compression of various working fluids, but is preferably used for CO ₂ gas compression as a preferred use example. This is because when CO ₂ gas is used as a refrigerant, the discharge pressure is higher than when a conventional HFC refrigerant is used, but in this scroll type fluid machine, the high pressure region is limited to the inside of the boss 28. This is because an appropriate load acts on the movable scroll 30 so as to be pressed toward the fixed scroll 32.

It is a longitudinal section showing a scroll type fluid machine of one embodiment of the present invention. It is the figure which expanded the area | region of the boss | hub vicinity of FIG. In FIG. 2, it is a figure which replaces the cross section of a drive shaft and eccentric bushing with an outer peripheral surface. It is the figure which expanded the boss vicinity in the scroll type fluid machine of a modification. In FIG. 4, it is a figure which replaces an outer peripheral surface with the cross section of a drive shaft and eccentric bushing. It is a top view which shows the end surface of the eccentric bush of FIG. 5 with a seal ring.

Explanation of symbols

16 Drive shaft 16a Internal flow path 24 Eccentric bush 26 Sliding bearing 28 Boss 30 Movable scroll 30a End plate 64 Seal ring

Claims (4)

A movable scroll disposed within the housing and pivotable relative to the fixed scroll;
A boss integrally formed on the back surface of the end plate of the movable scroll;
A drive shaft having an internal channel opened to any part of the end to supply lubricating oil at a high pressure to an end surrounded by a bearing on the boss and a region inside the boss;
A scroll type fluid machine, comprising: a seal member disposed in an inner region of the boss and partitioning between an opening of the internal flow path and an outer region of the boss.   2. The scroll fluid machine according to claim 1, further comprising a communication groove formed on an outer surface of the drive shaft and configured to communicate regions separated from each other by the seal member.   3. The scroll type fluid machine according to claim 1, further comprising an oil groove that is formed on an outer peripheral surface of the drive shaft and vertically cuts an area of the outer peripheral surface of the drive shaft surrounded by the bearing. The scroll type fluid machine according to any one of claims 1 to 3, wherein the scroll type fluid machine is used to compress CO ₂ gas.

Images