SCROLL COMPRESSOR

TECHNICAL FIELD

The present invention relates to a scroll compressor, and particularly to a scroll compressor for use in a refrigeration circuit of an air conditioner for vehicles.

BACKGROUND ART

Patent Document 1 discloses a scroll compressor including: a fixed scroll and a movable scroll accommodated in a housing, the housing supporting a rotary shaft via a bearing; and a shaft seal mechanism fitted between the rotary shaft and the housing, in which a communication passage for communicating the seal chamber with the side of a suction chamber of refrigerant is formed as lubricating means of the shaft seal mechanism.

PRIOR ART DOCUMENT
Patent Document

Patent Document 1: Japanese Patent No. 2868998

SUMMARY OF THE INVENTION
Problems to be Solved by the Invention

When a compressor has a structure in which a suction port is provided on an outer peripheral side of a scroll unit in an outer peripheral wall of a housing, since a refrigerant introduced from the suction port can be immediately sucked into the scroll unit, improvement of compression efficiency of the refrigerant can be expected. On the other hand, in the compressor having such a structure, the flow rate of the refrigerant flowing into a portion apart from the suction port in the housing is reduced and thus, particularly, deterioration of lubrication of a shaft seal mechanism or a lip seal which is a sealing device, has conventionally been a concern.

In a case such as Patent Document 1, in which a communication passage for communicating the seal chamber with the side of the suction chamber of refrigerant is simply formed, the communication passage will become long when the lip seal is away from the suction port, making it difficult to sufficiently supply lubricating oil to the lip seal.

The present invention has been made in view of the above-mentioned problems, and has its object to provide a scroll compressor which allows to significantly reduce wear of the sealing device while enhancing the compression efficiency of the compressor by actively guiding lubricating oil to the sealing device and, by extension, ensures a residual fastening margin of the sealing device with respect to the rotary shaft, thereby maintaining the sealing performance of the compressor over a long period of time.

Means for Solving the Problems

In order to achieve the above described object, a scroll compressor of the present invention includes: a scroll unit for compressing a refrigerant by orbiting of a movable scroll relative to a fixed scroll; a crank mechanism for converting rotary motion of a rotary shaft into orbiting motion of the movable scroll and transferring the orbiting motion; a housing for accommodating the scroll unit, the housing including a suction port of the refrigerant on an outer peripheral wall located on an outer peripheral side of the scroll unit; and a sealing device for sealing between the housing and the rotary shaft, wherein the housing includes: a crank chamber in which the crank mechanism is positioned, a seal chamber in which the sealing device is positioned, a communication hole for communicating the crank chamber with the seal chamber, and a first guide groove extending from an opening of the communication hole in the seal chamber to a vicinity of the sealing device.

Preferably, the housing further includes a second guide groove in which an opening of the communication hole in the crank chamber is positioned.

Preferably, the crank mechanism includes a counterweight attached to the rotary shaft, and the communication hole is formed at a position which is intermittently covered by the counterweight as the counterweight circles.

Preferably, the communication hole is inclined along a circling direction of the counterweight with respect to a radial direction of the rotary shaft.

Preferably, the counterweight has an inclined surface inclined with respect to an axis of the rotary shaft.

Preferably, the counterweight has a stepped surface protruding in a radial direction of the rotary shaft.

Advantageous Effects of the Invention

According to the scroll compressor of the present invention, it is possible to significantly reduce wear of the sealing device while enhancing the compression efficiency of the compressor by actively guiding lubricating oil to the sealing device and, by extension, ensure a residual fastening margin of the sealing device with respect to the rotary shaft, thereby maintaining the sealing performance of the compressor over a long period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical cross-sectional view of a scroll compressor according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a scroll compressor with parts of the crank chamber and the seal chamber of FIG. 1 being enlarged.

FIG. 3 is a plan view of the front housing of FIG. 1 as viewed from its opening end side.

FIG. 4 is a plan view showing a variant of FIG. 3.

FIG. 5 is a plan view showing a further variant of FIG. 3.

FIG. 6 is a vertical cross-sectional view of a scroll compressor with parts of the crank chamber and the seal chamber according to the second embodiment of the present invention being enlarged.

FIG. 7 is a plan view of the front housing of FIG. 6 as viewed from its opening end side.

FIG. 8 is a plan view of a front housing according to a third embodiment of the present invention as viewed from its opening end side.

FIG. 9 is a side view showing a counterweight according to a fourth embodiment of the present invention, with the counterweight being mounted on a rotary shaft.

FIG. 10 is a side view showing a variant of FIG. 9.

FIG. 11 is a side view illustrating a further variant of FIG. 9.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, each embodiment of the present invention will be described based on the drawings.

First Embodiment

FIG. 1 is a vertical cross-sectional view of a scroll compressor 1 according to a first embodiment of the present invention. This compressor 1 is incorporated, for example, in a refrigeration circuit of a vehicle air-conditioner mounted on a vehicle and is used for compressing refrigerant circulating in a refrigeration circuit.

The compressor 1 includes a rear housing (housing) 2 and a front housing (housing) 4, and a scroll unit 6 is disposed in the rear housing 2. The scroll unit 6 is made up of a fixed scroll 8 fixed to the rear housing 2, and a movable scroll 10 assembled so as to engage with the fixed scroll 8. The fixed scroll 8 includes an end plate 8a, and a fixed spiral body 8b integrally formed with the end plate 8a, and the movable scroll 10 includes an end plate 10a, and a movable spiral body 10b integrally molded with the end plate 10a, and the fixed spiral body 8b and the movable spiral body 10b are engaged with each other.

An ejection chamber 12 is formed between an end wall 2a of the rear housing 2 and the fixed scroll 8 in the rear housing 2. This ejection chamber 12 can communicate an ejection hole 14 formed in the end plate 8a of the fixed scroll 8 with a compression chamber 18 formed between the fixed scroll 8 and the movable scroll 10 via an ejection valve 16 of a reed valve type. In the outer peripheral wall 2b of the rear housing 2, an ejection port 20 is formed at a position proximal to the end wall 2a, and the ejection chamber 12 is communicated with a refrigerant circulation passage of the refrigeration circuit via the ejection port 20.

Moreover, a suction port 22 of the refrigerant is provided on the outer peripheral side of the scroll unit 6 in the outer peripheral wall 2b of the rear housing 2, and the refrigerant introduced via the suction port 22 from the refrigerant circulation passage is quickly sucked into the scroll unit 6.

On the other hand, the rotary shaft 24 is disposed in the front housing 4, and the rotary shaft 24 has a large-diameter shaft part 24a and a small-diameter shaft part 24b. Moreover, a large-diameter inner peripheral surface 4b, an intermediate-diameter inner peripheral surface 4c, and a small-diameter inner peripheral surface 4d are formed in the order from an opening end 4a located on the rear housing 2 side in the front housing 4 by stepwisely reducing the diameter of the inner periphery thereof.

A large-diameter shaft part 24a is rotatably supported on an intermediate-diameter inner peripheral surface 4c of the front housing 4 via a bearing 26 which is a needle bearing, and the small-diameter shaft part 24b is rotatably supported on the small-diameter inner peripheral surface 4d of the front housing 4 via a bearing 28 which is a ball bearing. Moreover, a lip seal (sealing device) 30 is disposed between the small-diameter shaft part 24b and the small-diameter inner peripheral surface 4d of the front housing 4. The outer periphery side of the lip seal 30 is mounted to the small-diameter inner peripheral surface 4d, and functions as a sealing device by the lip part located on the inner periphery side coming into contact with the small-diameter shaft part 24b during rotation, to partition the inside of the front housing 4 in an airtight manner.

The small-diameter shaft part 24b of the rotary shaft 24 protrudes from the front housing 4, and this protruding end is interconnected with a drive pulley 32 having an electromagnetic clutch built-in. The drive pulley 32 is rotatably supported on the front housing 4 via a bearing 34 which is a ball bearing. The drive pulley 32 is connected to an output pulley on the side of the engine of the vehicle via a belt, and receives the power of the engine, thereby being rotated.

On the other hand, a crankpin 24c is protruded toward the movable scroll 10 from the large-diameter shaft part 24a of the rotary shaft 24. The crankpin 24c, which is provided at a position eccentric from the axial center of the rotary shaft 24, is inserted and fitted into a crankpin hole 38 drilled in an eccentric bush 36. The crankpin 24c supports the eccentric bush 36 by its base end part 24c1. Moreover, the eccentric bush 36 supports a boss 41 of the movable scroll 10 via a bearing 40 which is a needle bearing.

Moreover, a counterweight 42 is attached to the crankpin 24c so as to be interposed between the eccentric bush 36 and the large-diameter shaft part 24a. The counterweight 42, which is made up by superposing a plurality of large and small arc-shaped plates 42a in an axial direction of the rotary shaft 24, cancels centrifugal force acting on the rotary shaft 24 as the movable scroll 10 orbits, thereby balancing the orbiting of the movable scroll 10.

In this way, a crank mechanism 44 which converts rotary motion of the rotary shaft 24 into orbiting motion of the movable scroll 10 and transfers the orbiting motion, is made up of the above described crankpin 24c, eccentric bush 36, boss 41, and counterweight 42.

Moreover, a rotation prevention mechanism 46 of a ball coupling type is disposed between an end plate 10a of the movable scroll 10 and an opening end 4a of the front housing 4. The rotation prevention mechanism 46 prevents the rotation of the movable scroll 10 without hindering the orbiting motion of the movable scroll 10 with respect to the fixed scroll 8.

In the compressor 1 as thus configured, when an electromagnetic clutch in the drive pulley 32 is ON-operated during driving of engine, and the rotary shaft 24 is rotated together with the drive pulley 32, the eccentric bush 36 into which the crankpin 24c is fitted rotates. As a result, orbiting motion is imparted to the movable scroll 10 via the boss 41 with rotation being prevented by the rotation prevention mechanism 46.

When the movable scroll 10 undergoes orbiting motion with respect to the fixed scroll 8, the refrigerant sucked from the refrigerant circulation passage via the suction port 22 is introduced into the scroll unit 6, and the fixed scroll 8 and the movable scroll 10 cooperate. As a result, a compression chamber 18 of refrigerant including lubricating oil is partitioned and formed between the fixed spiral body 8b and the movable spiral body 10b. In the compression chamber 18, the volume thereof is reduced while the movable spiral body 10b is moved toward the center of the fixed spiral body 8b by the orbiting motion of the movable scroll 10 with respect to the fixed scroll 8, and thus the refrigerant is compressed. The compressed refrigerant is ejected to the ejection chamber 12 via the ejection hole 14, and fed to the refrigerant circulation passage from the ejection port 20.

Here, a crank chamber 48 is partitioned inside a large-diameter inner peripheral surface 4b in the front housing 4. The crank chamber 48 is a space in the front housing 4, in which the crank mechanism 44 is positioned, and smooth orbiting of the counterweight 42 is allowed as the rotary shaft 24 rotates. Further, in the crank chamber 48, an annulus-shaped base surface 48a which substantially intersects at right angles with the axis of the rotary shaft 24 is formed as a stepped surface between the large-diameter inner peripheral surface 4b and the intermediate-diameter inner peripheral surface 4c of the front housing 4, and an arc-shaped plate 42a of the counterweight 42 is positioned in proximity to the base surface 48a.

On the other hand, in the front housing 4, a seal chamber 50 is partitioned from inner side of the intermediate-diameter inner peripheral surface 4c to the inner side of the small-diameter inner peripheral surface 4d. The seal chamber 50 is a space in which a lip part of the lip seal 30 is positioned, and an annulus-shaped base surface 50a which substantially intersects at right angles with the axis of the rotary shaft 24 is formed as a stepped surface between the intermediate-diameter inner peripheral surface 4c and the small-diameter inner peripheral surface 4d of the front housing 4, and a bearing 26 mounted to the intermediate-diameter inner peripheral surface 4c is positioned in proximity to the base surface 50a.

FIG. 2 is an enlarged cross-sectional view of parts of the crank chamber 48 and the seal chamber 50, and FIG. 3 is a plan view of the front housing 4 as viewed from the opening end 4a side thereof. As shown in FIGS. 2 and 3, in the present embodiment, two communication holes 52 which communicate the crank chamber 48 with the seal chamber 50 are penetrated through in the front housing 4 at symmetric positions on one diagonal line interposing the rotary shaft 24. Each communication hole 52 is formed at a position to extend linearly inclined with respect to the axis of the rotary shaft 24 and along the radial direction of the rotary shaft 24, to be opened in the base surface 48a in the crank chamber 48, and to be intermittently covered by the arc-shaped plate 42a as the counterweight 42 circles.

On the other hand, in the seal chamber 50, each communication hole 52 is opened in the vicinity of the base surface 50a of the intermediate-diameter inner peripheral surface 4c. The openings on the crank chamber 48 side and the seal chamber 50 side of each communication hole 52 are substantially positioned on a diameter line of the rotary shaft 24. Further, a guide groove (first guide groove) 54 is concaved from the communication hole 52 opened in the intermediate-diameter inner peripheral surface 4c to the vicinity of the lip part of the lip seal 30 in the base surface 50a which is an inner wall of the seal chamber 50. The guide groove 54, which is formed so as to have a bottom which is inclined in an arc shape with respect to the axis of the rotary shaft 24, extends linearly along the radial direction of the rotary shaft 24 from the communication hole 52 opened in the intermediate-diameter inner peripheral surface 4c to the vicinity of the lip part of the lip seal 30.

Here, when the refrigerant flows from the suction port 22 toward the compression chamber 18 side as the movable scroll 10 undergoes orbiting motion, refrigerant including lubricating oil will also flow to the back surface 10c side of the end plate 10a of the movable scroll 10. Moreover, the lubricating oil which has flown into the crank chamber 48 with the refrigerant lubricates the rotation prevention mechanism 46, the bearing 40, the bearing 26, and the lip seal 30.

Specifically, as shown by solid arrows in FIGS. 2 and 3, the refrigerant that has flown into the crank chamber 48 is temporarily compressed in a minute gap formed between the arc-shaped plate 42a and the base surface 48a proximal to the arc-shaped plate 42a as a result of the counterweight 42 circling in the two-dot-chain line arrow direction. The refrigerant that has been compressed in the crank chamber 48 is pushed out by differential pressure from the communication hole 52 into the seal chamber 50 in which pressure will be lower.

The refrigerant that has flown into seal chamber 50 from the crank chamber 48 through the communication hole 52 is guided to the lip seal 30 passing through the guide groove 54, and in this occasion, the lip seal 30 is appropriately lubricated by the lubricating oil contained in the refrigerant. On the other hand, as shown by a broken line in FIGS. 2 and 3, the refrigerant that has flown into the seal chamber 50 is returned to the crank chamber 48 through the bearing 26, and in that occasion, the bearing 26 is appropriately lubricated by the lubricating oil contained in the refrigerant. Thus, a lubricating oil recirculation passage is formed between the crank chamber 48 and the seal chamber 50.

As so far described, according to the present embodiment, in the case of a structure in which a suction port 22 is provided on the outer peripheral side of the scroll unit 6 as in the compressor 1, since the refrigerant introduced from the suction port 22 will be able to be sucked into the scroll unit 6 immediately, improvement in compression efficiency of refrigerant can be expected. On the other hand, in the compressor 1 of such a structure, the flow rate of the refrigerant flowing into a portion apart from the suction port 22 in the front housing 4 is reduced, and in particular, deterioration of lubrication of the lip seal 30 has conventionally been a concern.

Even in such a case, as a result of forming the communication hole 52 and the guide groove 54 in the front housing 4, thereby forming a lubricating oil circulation passage between the crank chamber 48 and the seal chamber 50, it is made possible to actively guide the lubricating oil to the lip seal 30. Therefore, it is possible to significantly reduce wear of the lip seal 30 while improving compression efficiency of the compressor 1, and by extension, to ensure a residual fastening margin of the lip seal 30 with respect to the small-diameter shaft part 24b, thereby maintaining the sealing performance of the compressor 1 over a long period of time. Note that the numbers of the communication hole 52 and the guide grooves 54 are not particularly limited, and for example, as shown in FIG. 4, two sets of the communication hole 52 and the guide groove 54 may be formed at symmetrical positions interposing the rotary shaft 24 on the two diagonal lines, or as shown in FIG. 5, only one set of the communication hole 52 and the guide groove 54 may be formed.

Second Embodiment

FIG. 6 is an enlarged cross-sectional view of parts of the crank chamber 48 and the seal chamber 50 according to a second embodiment of the present invention, and FIG. 7 is a plan view of the front housing 4 of FIG. 6 as viewed from its opening end 4a side. Note that regarding the same components as those of the first embodiment, description thereof may be omitted by giving them the same names and the reference symbols in the specification or the drawings.

As shown in FIGS. 6 and 7, in the base surface 48a of the front housing 4 of the present embodiment, two guide grooves (second guide grooves) 56 are concaved at positions interposing the rotary shaft 24 on the same diagonal line as that with the guide groove 54 of the base surface 50a. Each guide groove 56 extends linearly along the radial direction of the rotary shaft 24 from the vicinity of the large-diameter inner peripheral surface 4b to the vicinity of the intermediate-diameter inner peripheral surface 4c, and the communication hole 52 is formed in the bottom of the guide groove 56.

Thus, in the present embodiment, as a result of forming the guide groove 56 similar to the guide groove 54 of the base surface 50a at the opening position of the communication hole 52 in the base surface 48a, it is possible to effectively guide the lubricating oil adhered to the base surface 48a from the guide groove 56 to the communication hole 52, as shown by solid arrows in FIGS. 6 and 7, thus further actively guiding the lubricating oil to the lip seal 30. Therefore, it is possible to realize significant reduction of wear of the lip seal 30 and ensure a residual fastening margin of the lip seal 30 while improving the compression efficiency of the compressor 1, thereby maintaining the sealing performance of the compressor 1 over a long period of time.

Third Embodiment

FIG. 8 is a plan view of a front housing 4 according to a third embodiment of the present invention as viewed from its opening end 4a side. Note that the present embodiment will be described as a variant of FIG. 5 shown in the first embodiment, and regarding the same components as those of the first embodiment, description thereof may be omitted by giving them the same names and the reference symbols in the specification or the drawings.

As shown in FIG. 8, a communication hole 58 that communicates the crank chamber 48 with the seal chamber 50 is formed in the front housing 4. This communication hole 58 extends linearly inclined with respect to both the axis and radial directions of the rotary shaft 24 as shown by broken lines. Inclination with respect to the radial direction of the rotary shaft 24 is the direction along the circling direction of the counterweight 42. That is, the openings of the crank chamber 48 side and the seal chamber 50 side of the communication hole 58 are positioned included with respect to the diameter line of the rotary shaft 24.

Thus, in the present embodiment, as a result of forming a communication hole 58 having a different shape from those of the communication holes 52 of the first and second embodiments, as shown solid arrows in FIG. 8, it is possible to guide lubricating oil to the lip seal 30 further effectively and quickly by exploiting force in the circling direction of the counterweight 42 which acts on the refrigerant and the lubricating oil which have flown into the communication hole 58. Therefore, it is possible to realize significant reduction of wear of the lip seal 30 and ensure a residual fastening margin of the lip seal 30 while improving the compression efficiency of the compressor 1, thereby maintaining the sealing performance of the compressor 1 over a long period of time.

Fourth Embodiment

FIG. 9 is a side view showing a counterweight 60 according to a fourth embodiment of the present invention in a state of being mounted to the rotary shaft 24. Note that regarding the same components as those of any of the first to the third embodiments, description thereof may be omitted by giving them the same names and the reference symbols in the specification or the drawings.

As shown in FIG. 9, the counterweight 60 of the present embodiment is configured such that a radial end surface 60a1 of each arc-shaped plate 60a is inclined with respect to the axis of the rotary shaft 24 and forms a flush inclined surface 62. This inclined surface 62, which is inclined in a closing direction to the axis from the crankpin 24c side toward the large-diameter shaft part 24a, guides the lubricating oil adhered to the radial end surface 60a1 of each arc-shaped plate 60a toward the communication hole 52 or the communication hole 58 as shown solid arrows, as the counterweight 60 circles.

As a result of the counterweight 60 being provided with the inclined surface 62 in the present embodiment, it is possible to effectively guide the lubricating oil adhered to the radial end surface 60a1 of each arc-shaped plate 60a into the communication hole 52 or the communication hole 58, and more actively guide the lubricating oil to the lip seal 30. Therefore, it is possible to realize significant reduction of wear of the lip seal 30 and ensure a residual fastening margin of the lip seal 30 while improving the compression efficiency of the compressor 1, thereby maintaining the sealing performance of the compressor 1 over a long period of time.

Note that, without being limited to the above described one, for example as shown in FIG. 10, an inclined surface 64 in which only the radial end surface 60a1 of the arc-shaped plate 60a closest to the large-diameter shaft part 24a is inclined may be formed. Moreover, as shown in FIG. 11, a stepped surface 66 may be formed from the radial end surface 60a1 of each arc-shaped plate 60a by causing one of the each arc-shaped plate 60a to protrude in the radial direction of the rotary shaft 24. In such cases, as shown by solid arrows in FIGS. 10 and 11, it is possible to effectively guide the lubricating oil adhered to the counterweight 60 to flow or drip into the communication hole 52 or the communication hole 58.

The present invention will not be limited to each embodiment described above, and various modifications can be made thereto.

For example, in each embodiment described above, an engine-driven scroll compressor 1 which is incorporated in an air conditioner for vehicles has been described. However, the present invention can be applied to integrated electric-motor-driven scroll compressors and general scroll compressors in various fields which use various working fluids.

Explanation of Reference Signs

- 1 Scroll compressor
- 2 Rear housing (housing)
- 2
  b Outer peripheral wall
- 4 Front housing (housing)
- 6 Scroll unit
- 8 Fixed scroll
- 10 Movable scroll
- 22 Suction port
- 24 Rotary shaft
- 30 Lip seal (sealing device)
- 42, 60 Counterweight
- 44 Crank mechanism
- 48 Crank chamber
- 50 Seal chamber
- 52 Communication hole
- 54 Guide groove (first guide groove)
- 56 Guide groove (second guide groove)
- 62, 64 Inclined surface
- 66 Stepped surface

SCROLL COMPRESSOR

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