EP4621233A1

EP4621233A1 - Thrust receiving mechanism

Info

Publication number: EP4621233A1
Application number: EP23891294.3A
Authority: EP
Inventors: Hiroshi Suzuki; Yuichiro Tokunaga
Original assignee: Eagle Industry Co Ltd
Current assignee: Eagle Industry Co Ltd
Priority date: 2022-11-17
Filing date: 2023-10-20
Publication date: 2025-09-24
Also published as: JPWO2024106138A1; KR20250041052A; WO2024106138A1; CN119768611A

Abstract

There is provided a thrust receiving mechanism that allows a movable scroll to rotate eccentrically in a stable manner in a state where the movable scroll maintains the posture with respect to a fixed scroll. A thrust receiving mechanism 8 is provided on a back surface of a movable scroll 42 that slides relative to a fixed scroll 41 while rotating eccentrically, and is configured for generating a dynamic pressure on the back surface of the movable scroll 42, and the thrust receiving mechanism 8 includes a plurality of dynamic pressure generation portions 80 and pressing portions 81 that press the dynamic pressure generation portions 80.

Description

{TECHNICAL FIELD}

The present invention relates to a thrust receiving mechanism, for example, a thrust receiving mechanism used in a rotating machine including an eccentric mechanism.

{BACKGROUND ART}

Machines that are rotationally driven and that are used in various industrial fields include not only a rotating machine in which a central shaft rotates while being held at a fixed position, but also a rotating machine that a central shaft rotates eccentrically. One example of a rotating machine that rotates eccentrically is a scroll compressor or the like, and this type of compressor includes a scroll compression mechanism composed of a fixed scroll including a scroll wrap on a surface of an end plate and a movable scroll including a scroll wrap on a surface of an end plate, an eccentric mechanism for eccentrically rotating a rotating shaft, and the like, and has a mechanism for pressurizing a fluid supplied from a low-pressure chamber on a radial outer side of both the scrolls and discharging high-pressure fluid from a discharge hole, which is formed at the center of the fixed scroll, by sliding the movable scroll relative to the fixed scroll while eccentrically rotating the movable scroll due to the rotation of the rotating shaft.
For example, a scroll compressor disclosed in Patent Citation 1 includes a fixed scroll, a movable scroll, and a thrust bearing. The movable scroll is configured to be eccentrically rotatable in a state where the movable scroll maintains the posture with respect to the fixed scroll. In the following description, the eccentric rotation of the movable scroll in a state where the movable scroll maintains the posture with respect to the fixed scroll may be simply referred to as the eccentric rotation of the movable scroll. The thrust bearing is disposed to be able to support the movable scroll on which a reaction force acts when a refrigerant is compressed.
In addition, some of the refrigerant compressed by the scroll compression mechanism is supplied to a space on a back surface side of the movable scroll. The movable scroll is pressed against the fixed scroll by the refrigerant. Accordingly, leakage of the refrigerant in an axial direction between both the scrolls is reduced, and the compression efficiency of the scroll compressor is increased.
In addition, the thrust bearing includes a ring-shaped plate. A plurality of bearing mechanisms, in each of which a plurality of grooves are provided in a substantially radial shape toward a land at the center of a sliding surface of the ring-shaped plate, are evenly spaced on the sliding surface that comes into contact with the movable scroll. As the movable scroll rotates eccentrically, locations on a sliding surface of the movable scroll that face the respective bearing mechanisms move to revolve about the radial centers of the bearing mechanisms that the locations face. Each bearing mechanism is disposed at a position with substantially the same diameter as the revolving range of the sliding surface of the movable scroll.

{CITATION LIST}

{Patent Literature}

Patent Citation 1: JP H9-317666 A (Page 4, FIG. 2)

{SUMMARY OF INVENTION}

{Technical Problem}

In the scroll compressor as disclosed in Patent Citation 1, as described above, some of the refrigerant compressed by the scroll compression mechanism is supplied to the space on the back surface side of the movable scroll. In addition, as the movable scroll rotates eccentrically, dynamic pressure is generated at a position in each bearing mechanism, and the dynamic pressure acts in a direction in which a thrust force of the movable scroll is counteracted. For that reason, the ring-shaped plate can reduce a frictional force generated when the movable scroll rotates.
By the way, in the scroll compressor as disclosed in Patent Citation 1, the axial position of the movable scroll with respect to the fixed scroll or the angle of the movable scroll with respect to the fixed scroll may be displaced due to a change in pressure difference between the pressure between the fixed scroll and the movable scroll and the back pressure acting on the movable scroll, external disturbances, or the like.
In such a scroll compressor, dynamic pressure generated when the movable scroll separates from the ring-shaped plate may be reduced or disappear. Accordingly, as the movable scroll comes into sliding contact with the ring-shaped plate again, a strong frictional force is temporarily generated, and not only the eccentric rotation of the movable scroll is hindered, but also the movable scroll tilts easily. In addition, when the movable scroll tilts with respect to the ring-shaped plate, a difference may occur in the dynamic pressures generated in the bearing mechanisms. Accordingly, the eccentric rotation of the movable scroll becomes unstable, which is a risk.
The present invention has been made in view of such problems, and an object of the present invention is to provide a thrust receiving mechanism that allows a movable scroll to rotate eccentrically in a stable manner in a state where the movable scroll maintains the posture with respect to a fixed scroll.

{Solution to Problem}

In order to solve the foregoing problems, a thrust receiving mechanism according to the present invention is a thrust receiving mechanism provided on a back surface of a movable scroll that slides relative to a fixed scroll while rotating eccentrically, and configured for generating a dynamic pressure on the back surface of the movable scroll, the thrust receiving mechanism including: a plurality of dynamic pressure generation portions; and pressing portions that press the dynamic pressure generation portions. According to the aforesaid features of the present invention, the thrust receiving mechanism can cause the plurality of dynamic pressure generation portions to follow the back surface of the movable scroll in response to the displacement of the axial position or tilting of the movable scroll. For that reason, even when the displacement of the axial position or tilting of the movable scroll occurs, the thrust receiving mechanism can stably generate dynamic pressure. Accordingly, the thrust receiving mechanism allows the movable scroll to rotate eccentrically in a stable manner in a state where the movable scroll maintains the posture with respect to the fixed scroll.
It may be preferable that the plurality of dynamic pressure generation portions are disposed in an annular shape at spacings in a circumferential direction. According to this preferable configuration, the thrust receiving mechanism can generate dynamic pressures in the circumferential direction in a well-balanced manner.
It may be preferable that the pressing portions are provided on back portions of the respective dynamic pressure generation portions. According to this preferable configuration, the thrust receiving mechanism can cause the plurality of dynamic pressure generation portions to individually follow the movable scroll.
It may be preferable that the thrust receiving mechanism further includes movement restriction portions configured for restricting the dynamic pressure generation portion from moving toward a movable scroll side by a predetermined distance or more. According to this preferable configuration, the thrust receiving mechanism can hold each dynamic pressure generation portion. For that reason, the thrust receiving mechanism is easy to attach.
It may be preferable that the thrust receiving mechanism further includes tilting portions configured for allowing the dynamic pressure generation portion to tilt according to a tilting of the movable scroll. According to this preferable configuration, even when the movable scroll tilts, the thrust receiving mechanism can more reliably generate dynamic pressure.
It may be preferable that the thrust receiving mechanism further includes rotation restriction portions configured for restricting a rotation of the dynamic pressure generation portion. According to this preferable configuration, the thrust receiving mechanism can efficiently generate dynamic pressure.
It may be preferable that each of the dynamic pressure generation portions has a sliding surface having a circular shape that slides relative to the movable scroll, and the sliding surface is provided with a plurality of dynamic pressure grooves formed to be separated from each other in a circumferential direction. According to this preferable configuration, the dynamic pressure generation portion can stably generate dynamic pressure at any position in the circumferential direction through movement relative to the movable scroll.

{BRIEF DESCRIPTION OF DRAWINGS}

FIG. 1 is a schematic configuration view illustrating a scroll compressor to which a thrust receiving mechanism according to an embodiment of the present invention is applied.
FIG. 2 is a schematic view illustrating a sliding surface of the thrust receiving mechanism in the embodiment.
FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2.
FIG. 4 is a view taken in the direction of arrow B in FIG. 3.
FIG. 5 is a cross-sectional view taken along line C-C in FIG. 3.
FIG. 6 is a view for describing a sliding state between the thrust receiving mechanism and a side seal in the embodiment.
FIG. 7 is a view for describing a sliding state between the thrust receiving mechanism and the side seal when a rotating shaft has eccentrically rotated by 90 degrees from FIG. 6.
FIG. 8 is a view for describing a sliding state between the thrust receiving mechanism and the side seal when the rotating shaft has eccentrically rotated by 180 degrees from FIG. 6.
FIG. 9 is a view for describing a sliding state between the thrust receiving mechanism and the side seal when the rotating shaft has eccentrically rotated by 270 degrees from FIG. 6.
FIG. 10 is a view for describing the thrust receiving mechanism that follows a movable scroll in the embodiment.

{DESCRIPTION OF EMBODIMENTS}

A mode for implementing a thrust receiving mechanism according to the present invention will be described below based on an embodiment.

{Embodiment}

A thrust receiving mechanism according to an embodiment of the present invention will be described with reference to FIGS. 1 to 10.
The thrust receiving mechanism according to the embodiment of the present invention is applied to a rotating machine including an eccentric mechanism, for example, a scroll compressor C that suctions, compresses, and discharges a refrigerant serving as a fluid used in an air conditioning system of an automobile or the like. Incidentally, in the present embodiment, the refrigerant is a gas, and is mixed with lubricating oil in the form of mist.
First, the scroll compressor C will be described. As illustrated in FIG. 1, the scroll compressor C is mainly composed of a housing 1, a rotating shaft 2, an inner casing 3, a scroll compression mechanism 4, a side seal 7, a thrust receiving mechanism 8, and a drive motor M.
The housing 1 is composed of a casing 11 having a cylindrical shape, and a cover 12 that closes an opening of the casing 11. An opening of the casing 11 on the side axially opposite to the opening closed by the cover 12 is closed by the drive motor M.
Inside the casing 11, a low-pressure chamber 20 serving as an external space on a low-pressure side to which low-pressure refrigerant is supplied from a refrigerant circuit (not illustrated) through a suction port 10, a high-pressure chamber 30 from which high-pressure refrigerant compressed by the scroll compression mechanism 4 is discharged, and a back pressure chamber 50 serving as an external space on a high-pressure side to which some of the refrigerant compressed by the scroll compression mechanism 4 is supplied together with the lubricating oil are formed. Incidentally, the back pressure chamber 50 is formed inside the inner casing 3 having a cylindrical shape that is accommodated inside the casing 11.
A discharge communication passage 13 communicating between the refrigerant circuit (not illustrated) and the high-pressure chamber 30 is formed in the cover 12. In addition, a part of a back pressure communication passage 14 communicating between the high-pressure chamber 30 and the back pressure chamber 50 is formed in the cover 12 by branching off from the discharge communication passage 13. Incidentally, an oil separator 6 that separates the lubricating oil from the refrigerant is provided in the discharge communication passage 13.
The inner casing 3 is fixed in a state where an axial end portion of the inner casing 3 abuts against an end plate 41a of a fixed scroll 41 constituting the scroll compression mechanism 4. In addition, a suction communication passage 15 is formed in a side wall of the inner casing 3 so as to penetrate therethrough in a radial direction. Namely, the low-pressure chamber 20 is formed from the outside of the inner casing 3 to the inside of the inner casing 3 via the suction communication passage 15. The refrigerant supplied to the inside of the inner casing 3 through the suction communication passage 15 is suctioned into the scroll compression mechanism 4.
In addition, a through-hole 3a and 16 recesses 3b that are evenly spaced are formed in the inner casing 3. The through-hole 3a is formed at the radial center of the inner casing 3. In addition, the through-hole 3a is formed with a diameter large enough to allow the eccentric rotation of an eccentric portion 2a and a counterweight portion 2b of the rotating shaft 2.
In addition, a seal ring 44 is fixed to an inner periphery of the through-hole 3a. Accordingly, a gap between the through-hole 3a and the rotating shaft 2 inserted into the through-hole 3a is sealed, and the low-pressure chamber 20 formed on a radial outer side of a movable scroll 42 and the back pressure chamber 50 formed on a back surface side of the movable scroll 42 are partitioned off from each other.
The recesses 3b are recessed into a surface 3c, which faces the movable scroll 42, at a position closer to the radial outer side than the through-hole 3a, and have a circular shape when viewed in an axial direction.
The scroll compression mechanism 4 is mainly composed of the fixed scroll 41 fixed to the cover 12 in a sealed manner, and the movable scroll 42 accommodated inside the inner casing 3.
The fixed scroll 41 is made of metal, and includes a scroll wrap 41b protruding from a surface of the end plate 41a having a disk shape, namely, from the end plate 41a toward the movable scroll 42. In addition, a recess 41c formed by recessing a radial inner side of a back surface of the end plate 41a, namely, an end surface of the end plate 41a in a direction opposite to the cover 12, the end surface abutting against the cover 12, is formed in the fixed scroll 41, and the high-pressure chamber 30 is defined by the recess 41c and the cover 12.
The movable scroll 42 is made of metal, and includes a scroll wrap 42b protruding from a surface of an end plate 42a having a disk shape, namely, from the end plate 42a toward the fixed scroll 41. In addition, a boss 42c protruding from the center of a back surface of the end plate 42a is formed on the movable scroll 42.
The boss 42c is inserted into the through-hole 3a of the inner casing 3. In addition, the eccentric portion 2a formed on the rotating shaft 2 is inserted into the boss 42c so as to be capable of relative rotation. Incidentally, in the present embodiment, the eccentric portion 2a of the rotating shaft 2 and the counterweight portion 2b protruding from the rotating shaft 2 in a radially outward direction constitute an eccentric mechanism that eccentrically rotates the rotating shaft 2.
When the rotating shaft 2 is rotationally driven by the drive motor M, the eccentric portion 2a rotates eccentrically, and the movable scroll 42 slides relative to the fixed scroll 41 in a state where the movable scroll 42 maintains the posture with respect to the fixed scroll 41 while rotating eccentrically. At this time, the movable scroll 42 rotates eccentrically with respect to the fixed scroll 41, and the contact position between the wraps 41b and 42b moves sequentially in a rotation direction along with this rotation, and a compression chamber 40 formed between the wraps 41b and 42b is gradually reduced while moving toward the center. Accordingly, the refrigerant suctioned into the compression chamber 40 from the low-pressure chamber 20 formed on the radial outer side of the scroll compression mechanism 4 is compressed, and finally, the high-pressure refrigerant is discharged into the high-pressure chamber 30 through a discharge hole 41d provided at the center of the fixed scroll 41.
In addition, an orifice (not illustrated) is provided in the back pressure communication passage 14. The refrigerant in the high-pressure chamber 30, the pressure of which is adjusted to be reduced by the orifice, is supplied to the back pressure chamber 50, together with the lubricating oil separated by the oil separator 6. At this time, the pressure in the back pressure chamber 50 is adjusted to be higher than the pressure in the low-pressure chamber 20. Incidentally, a pressure relief hole 16 penetrating through the inner casing 3 in the radial direction and communicating between the low-pressure chamber 20 and the back pressure chamber 50 is formed in the inner casing 3, and a pressure adjustment valve 45 is provided in the pressure relief hole 16. The pressure adjustment valve 45 opens when the pressure in the back pressure chamber 50 becomes higher than a set value.
Next, the side seal 7 will be described. The side seal 7 is made of resin, has a rectangular cross section and an annular shape when viewed in the axial direction, and is fixed to the back surface of the end plate 42a of the movable scroll 42.
A sliding surface 7a that abuts against each sliding surface 80a of the thrust receiving mechanism 8 is formed on the side seal 7. The sliding surface 7a is a flat surface, and constitutes a back surface-side sliding surface of the movable scroll 42.
Next, the thrust receiving mechanism 8 will be described. As illustrated in FIGS. 1 and 2, the thrust receiving mechanism 8 is composed of the inner casing 3; 16 dynamic pressure pieces 80 serving as a plurality of dynamic pressure generation portions; 16 springs 81 serving as a plurality of pressing portions (refer to FIG. 1); and 16 pins 82.
Referring to FIGS. 3 to 5, each of the dynamic pressure pieces 80 is made of metal, and is formed in a cylindrical shape with a step on a radial inner side. The dynamic pressure piece 80 includes a tubular wall 80b and a bottom wall 80c having an annular plate shape. In addition, an outer diameter of the dynamic pressure piece 80 is smaller than a diameter of the recess 3b of the inner casing 3. In addition, the dynamic pressure piece 80 has substantially the same axial dimension as the recess 3b.
The tubular wall 80b has a cylindrical shape extending in the axial direction. In addition, an axial end surface of the tubular wall 80b located on the side opposite to the bottom wall 80c is the sliding surface 80a having an annular shape.
As illustrated in FIG. 4, eight dynamic pressure grooves 83 that are evenly spaced are provided on the sliding surface 80a, and the other places form a land 84 that is flat.
The dynamic pressure grooves 83 are recessed in the axial direction, and are spiral grooves extending while curving in a counterclockwise direction from a radial outer side toward the radial inner side. In addition, radial outer ends of the dynamic pressure grooves 83 are open toward the radial outer side of the sliding surface 80a, and radial inner ends of the dynamic pressure grooves 83 are tapered and closed.
As illustrated in FIG. 3, the bottom wall 80c has substantially the same outer diameter as the tubular wall 80b, and a smaller inner diameter than the tubular wall 80b.
As illustrated in FIGS. 3 to 5, a through-hole penetrating through the radial center of the dynamic pressure piece 80 in the axial direction is composed of a large-diameter hole 85, a small-diameter hole 86, and a key groove 87.
The large-diameter hole 85 is defined by the tubular wall 80b and the bottom wall 80c, and is a hole having a circular cross section and extending in the axial direction. In addition, the large-diameter hole 85 is open to a movable scroll 42 side.
The small-diameter hole 86 is defined by the bottom wall 80c, and is a hole having a circular cross section and extending in the axial direction. The small-diameter hole 86 has a smaller diameter than the large-diameter hole 85. In addition, the small-diameter hole 86 communicates with the large-diameter hole 85 on a sliding surface 80a side, and is open to a bottom side of the recess 3b on the side opposite to the sliding surface 80a.
The key groove 87 is recessed with a rectangular cross section from an inner peripheral surface of the bottom wall 80c toward the radial outer side, and is open to the radial inner side. Accordingly, the key groove 87 communicates with the small-diameter hole 86. In addition, the key groove 87 is a through-groove having a rectangular cross section and extending in the axial direction. The key groove 87 communicates with the large-diameter hole 85 on the sliding surface 80a side, and is open in the axial direction on the side opposite to the sliding surface 80a. The key groove 87 is formed closer to the radial inner side than an inner peripheral surface of the tubular wall 80b that defines the large-diameter hole 85.
The pin 82 includes a head 82a, a shaft 82b, and a key projection 82c.
The head 82a is formed in a disk shape, and has a smaller diameter than the large-diameter hole 85 and a larger diameter than the small-diameter hole 86.
The shaft 82b has a columnar shape extending from the radial center of the head 82a in the axial direction, and has a smaller diameter than the small-diameter hole 86.
The key projection 82c protrudes with a rectangular cross section from an outer peripheral surface of the shaft 82b in the radially outward direction. In addition, the key projection 82c has a quadrangular prism shape extending in the axial direction. A radial dimension of the shaft 82b at the key projection 82c is shorter than a radial dimension of the small-diameter hole 86 at the key groove 87. In addition, a dimension of the shaft 82b in a normal direction at the key projection 82c is shorter than a dimension of the small-diameter hole 86 in a normal direction at the key groove 87.
The dynamic pressure piece 80, the spring 81, and the pin 82 are disposed in the recess 3b of the inner casing 3.
In detail, the dynamic pressure piece 80 is loosely fitted in the recess 3b. The spring 81 is disposed between a bottom of the recess 3b and the dynamic pressure piece 80. The pin 82 is inserted into the through-hole of the dynamic pressure piece 80, and is fixed to the bottom of the recess 3b.
At this time, the head 82a of the pin 82 is inserted into the large-diameter hole 85 of the dynamic pressure piece 80, and is loosely fitted therein. In addition, the shaft 82b of the pin 82 is inserted into the small-diameter hole 86 of the dynamic pressure piece 80, and is loosely fitted therein. In addition, the key projection 82c of the pin 82 is inserted into the key groove 87 of the dynamic pressure piece 80, and is loosely fitted therein.
Accordingly, the dynamic pressure piece 80 is movable along an axis of the pin 82, and is slightly tiltable with respect to the pin 82.
As illustrated in FIGS. 3 and 4, the thrust receiving mechanism 8 includes movement restriction portions 90. Each of the movement restriction portions 90 is composed of the dynamic pressure piece 80 and the pin 82. The movement restriction portion 90 restricts the movement of the dynamic pressure piece 80 in a direction in which the dynamic pressure piece 80 comes out from the recess 3b by causing the dynamic pressure piece 80 to abut against the head 82a of the pin 82. In addition, the movement restriction portion 90 restricts the radial movement of the dynamic pressure piece 80 by causing the dynamic pressure piece 80 to abut against the pin 82. Accordingly, the thrust receiving mechanism 8 is easy to attach.
As illustrated in FIG. 3, the thrust receiving mechanism 8 includes tilting portions 91. Each of the tilting portions 91 is composed of the dynamic pressure piece 80 and the pin 82 that is inserted with play into the through-hole of the dynamic pressure piece 80. The tilting portion 91 allows the dynamic pressure piece 80 to tilt with respect to the pin 82 by a gap between the through-hole of the dynamic pressure piece 80 and the pin 82 (refer to FIGS. 10C and 10D).
As illustrated in FIGS. 3 to 5, the thrust receiving mechanism 8 includes rotation restriction portions 92. Each of the rotation restriction portions 92 is composed of the key groove 87 of the dynamic pressure piece 80 and the key projection 82c inserted into the key groove 87. The rotation restriction portion 92 restricts the rotation of the dynamic pressure piece 80 around the axis of the pin 82 by causing the key projection 82c to abut against an inner surface of the key groove 87.
As illustrated in FIGS. 6 to 9, when the sliding surface 7a of the side seal 7 is slid relative to each sliding surface 80a of the thrust receiving mechanism 8 by the rotation of the rotating shaft 2, dynamic pressure is generated between the sliding surfaces 7a and 80a. Hereinafter, this dynamic pressure will be described. Incidentally, in this description, in each figure, four dynamic pressure pieces 80 located in a 12 o'clock direction on the paper, a 9 o'clock direction on the paper, a 6 o'clock direction on the paper, and a 3 o'clock direction on the paper are illustrated as an example in an enlarged manner.
In addition, FIGS. 6 to 9 illustrate states where the boss 42c has rotated by 90 degrees (refer to FIG. 7), 180 degrees (refer to FIG. 8), and 270 degrees (refer to FIG. 9), with FIG. 6 as a reference for the counterclockwise direction, along a rotation trajectory of the boss 42c indicated by a black arrow when viewed from a fixed scroll 41 side. In addition, a sliding region between the sliding surface 7a of the side seal 7 and the sliding surface 80a of the thrust receiving mechanism 8 is schematically illustrated by dots. In addition, for convenience of description, regarding the rotating shaft 2, only the eccentric portion 2a inserted into the boss 42c is illustrated, and the illustration of the counterweight portion 2b and the like constituting the eccentric mechanism is omitted.
In FIG. 6, as indicated by a black arrow, the side seal 7 has slid counterclockwise relative to the sliding surface 80a of each dynamic pressure piece 80 from a state illustrated in FIG. 9. As indicated by two-dot chain lines, the side seal 7 overlaps the dynamic pressure groove 83 of each dynamic pressure piece 80 in the axial direction, the dynamic pressure groove 83 being located on a 12 o'clock direction side on the paper. In this relative sliding, the dynamic pressure piece 80 is restricted from rotating around the axis of the pin 82 by the rotation restriction portion 92.
According to this configuration, the fluid in the dynamic pressure groove 83 of each dynamic pressure piece 80, the dynamic pressure groove 83 being located on a 1 o'clock direction side on the paper, moves from the radial outer side of the dynamic pressure groove 83 toward the radial inner side thereof (refer to a dashed arrow in FIG. 6).
Accordingly, dynamic pressure is generated at the radial inner end of the dynamic pressure groove 83 of each dynamic pressure piece 80, the dynamic pressure groove 83 being located on the 1 o'clock direction side on the paper. As described above, the dynamic pressure pieces 80 are evenly spaced. For that reason, dynamic pressures are generated between the dynamic pressure pieces 80 and the side seal 7 at approximately predetermined spacings along a circumferential direction of the side seal 7. In addition, since the dynamic pressure piece 80 is restricted from rotating around the axis of the pin 82 by the rotation restriction portion 92 (refer to FIGS. 3 to 5), a high dynamic pressure is generated.
In FIG. 7, as indicated by a black arrow, the side seal 7 has slid counterclockwise relative to the sliding surface 80a of each dynamic pressure piece 80 from a state illustrated in FIG. 6. As indicated by two-dot chain lines, the side seal 7 overlaps the dynamic pressure groove 83 of each dynamic pressure piece 80 in the axial direction, the dynamic pressure groove 83 being located on a 9 o'clock direction side on the paper. In this relative sliding, the dynamic pressure piece 80 is restricted from rotating around the axis of the pin 82 by the rotation restriction portion 92.
According to this configuration, the fluid in the dynamic pressure groove 83 of each dynamic pressure piece 80, the dynamic pressure groove 83 being located on a 10 o'clock direction side on the paper, moves from the radial outer side of the dynamic pressure groove 83 toward the radial inner side thereof (refer to a dashed arrow in FIG. 7).
Accordingly, dynamic pressure is generated at the radial inner end of the dynamic pressure groove 83 of each dynamic pressure piece 80, the dynamic pressure groove 83 being located on the 10 o'clock direction side on the paper. For that reason, similarly to the state illustrated in FIG. 6, dynamic pressures are generated at approximately predetermined spacings along the circumferential direction of the side seal 7.
In FIG. 8, as indicated by a black arrow, the side seal 7 has slid counterclockwise relative to the sliding surface 80a of each dynamic pressure piece 80 from a state illustrated in FIG. 7. As indicated by two-dot chain lines, the side seal 7 overlaps the dynamic pressure groove 83 of each dynamic pressure piece 80 in the axial direction, the dynamic pressure groove 83 being located on a 6 o'clock direction side on the paper. In this relative sliding, the dynamic pressure piece 80 is restricted from rotating around the axis of the pin 82 by the rotation restriction portion 92.
According to this configuration, the fluid in the dynamic pressure groove 83 of each dynamic pressure piece 80, the dynamic pressure groove 83 being located on a 7 o'clock direction side on the paper, moves from the radial outer side of the dynamic pressure groove 83 toward the radial inner side thereof (refer to a dashed arrow in FIG. 8).
Accordingly, dynamic pressure is generated at the radial inner end of the dynamic pressure groove 83 of each dynamic pressure piece 80, the dynamic pressure groove 83 being located on the 7 o'clock direction side on the paper. For that reason, similarly to the state illustrated in FIG. 6, dynamic pressures are generated at approximately predetermined spacings along the circumferential direction of the side seal 7.
In FIG. 9, as indicated by a black arrow, the side seal 7 has slid counterclockwise relative to the sliding surface 80a of each dynamic pressure piece 80 from a state illustrated in FIG. 8. As indicated by two-dot chain lines, the side seal 7 overlaps the dynamic pressure groove 83 of each dynamic pressure piece 80 in the axial direction, the dynamic pressure groove 83 being located on a 3 o'clock direction side on the paper. In this relative sliding, the dynamic pressure piece 80 is restricted from rotating around the axis of the pin 82 by the rotation restriction portion 92.
According to this configuration, the fluid in the dynamic pressure groove 83 of each dynamic pressure piece 80, the dynamic pressure groove 83 being located on a 4 o'clock direction side on the paper, moves from the radial outer side of the dynamic pressure groove 83 toward the radial inner side thereof (refer to a dashed arrow in FIG. 9).
Accordingly, dynamic pressure is generated at the radial inner end of the dynamic pressure groove 83 of each dynamic pressure piece 80, the dynamic pressure groove 83 being located on the 4 o'clock direction side on the paper. For that reason, similarly to the state illustrated in FIG. 6, dynamic pressures are generated at approximately predetermined spacings along the circumferential direction of the side seal 7.
Next, the following of each dynamic pressure piece 80 with respect to the side seal 7 will be described with reference to FIG. 10. Incidentally, in each drawing, the dynamic pressure piece 80 located at the 12 o'clock direction on the paper of FIG. 6 is illustrated as an example. In addition, for convenience of description, in FIG. 10, the axial movement (refer to FIGS. 10A and 10B) or tilting (refer to FIGS. 10C and 10D) of the dynamic pressure piece 80 with respect to the pin 82 is illustrated in an exaggerated manner.
The axial position of the movable scroll 42 with respect to the fixed scroll 41 or the angle of the movable scroll 42 with respect to the fixed scroll 41 may be displaced due to a change in pressure difference between the pressure between the fixed scroll 41 and the movable scroll 42 and the pressure acting on the back surface of the movable scroll 42 from the refrigerant in the back pressure chamber 50, the action of external disturbances, or the like.
First, the axial movement of the dynamic pressure piece 80 will be described. When the movable scroll 42 moves in a direction in which the movable scroll 42 separates from the fixed scroll 41 as transitioning from FIG. 10A to FIG. 10B, the dynamic pressure piece 80 moves in the same direction together with the movable scroll 42 while compressing and deforming the spring 81. Meanwhile, the dynamic pressure piece 80 continues to be pressed by the spring 81. Accordingly, the sliding contact state between the sliding surface 80a of the dynamic pressure piece 80 and the sliding surface 7a of the side seal 7 is maintained.
In addition, as described above, the dynamic pressure piece 80 has substantially the same axial dimension as the recess 3b. For that reason, while the movable scroll 42 is allowed to move in the axial direction, the movable scroll 42 can be prevented from coming into contact with the surface 3c of the inner casing 3 that faces the movable scroll 42.
When the movable scroll 42 moves in a direction in which the movable scroll 42 approaches the fixed scroll 41 as transitioning from FIG. 10B to FIG. 10A, the dynamic pressure piece 80 is pressed by the spring 81 that elastically returns, and moves in the same direction together with the movable scroll 42. Accordingly, the sliding contact state between the sliding surface 80a of the dynamic pressure piece 80 and the sliding surface 7a of the side seal 7 is maintained.
Next, the tilting of the dynamic pressure piece 80 will be described. When the movable scroll 42 tilts in either direction as transitioning from FIG. 10A to FIG. 10C or FIG. 10D, the dynamic pressure piece 80 is also tilted with respect to the axis of the pin 82, namely, an axis of the rotating shaft 2, by the tilting portion 91. At this time, the sliding contact state between the sliding surface 80a of the dynamic pressure piece 80 and the sliding surface 7a of the side seal 7 is maintained.
Incidentally, FIG. 10C illustrates a state where the dynamic pressure piece 80 tilts in a direction in which a radial outer-side end portion of the dynamic pressure piece 80 separates from the fixed scroll 41, and FIG. 10D illustrates a state where the dynamic pressure piece 80 tilts in a direction in which the radial outer-side end portion of the dynamic pressure piece 80 approaches the fixed scroll 41. Meanwhile, the dynamic pressure piece 80 held by the pin 82 fixed along a central axis of the recess 3b having a circular shape is tiltable at substantially the same angle in various directions.
As described above, the thrust receiving mechanism 8 of the present embodiment can cause the plurality of dynamic pressure pieces 80 to follow the back surface of the movable scroll 42 in response to the displacement of the axial position or tilting of the movable scroll 42. For that reason, even when the displacement of the axial position or tilting of the movable scroll 42 occurs, the thrust receiving mechanism 8 can stably generate dynamic pressure acting in a direction in which a thrust force of the movable scroll is counteracted, by causing each dynamic pressure piece 80 to follow. Accordingly, the thrust receiving mechanism 8 allows the movable scroll 42 to rotate eccentrically in a stable manner in a state where the movable scroll 42 maintains the posture with respect to the fixed scroll 41.
By stably generating dynamic pressure in such a manner, the thrust receiving mechanism 8 can slightly separate the sliding surfaces 7a and 80a from each other, and can stably form a fluid film with the fluid. Accordingly, the thrust receiving mechanism 8 can reduce a frictional force generated by the sliding contact between the sliding surfaces 7a and 80a.
In addition, even when the eccentric rotation position, the axial position, or the tilt angle of the movable scroll 42 is displaced, the thrust receiving mechanism 8 can continue to keep the sliding surfaces 80a of the dynamic pressure pieces 80, which are evenly spaced in the circumferential direction, namely, are disposed in an annular shape at spacings in the circumferential direction, in sliding contact with the side seal 7. For that reason, dynamic pressures generated at approximately predetermined spacings along the circumferential direction of the side seal 7 are substantially the same. In such a manner, the thrust receiving mechanism 8 can generate dynamic pressures in the circumferential direction in a well-balanced manner.
In addition, in the thrust receiving mechanism 8, one spring 81 is disposed on a back portion of each dynamic pressure piece 80. For that reason, the thrust receiving mechanism 8 can cause the plurality of dynamic pressure pieces 80 to individually follow the movable scroll 42.
In addition, even when the movable scroll 42 is tilted by the tilting portion 91, the thrust receiving mechanism 8 more easily disposes the sliding surfaces 7a and 80a to be substantially parallel to each other. Accordingly, the thrust receiving mechanism 8 can more reliably generate dynamic pressures.
In addition, the thrust receiving mechanism 8 is restricted from rotating in response to the sliding contact of the side seal 7 therewith by the rotation restriction portion 92. Accordingly, the speed at which the side seal 7 moves with respect to each dynamic pressure piece 80 is more easily maintained. The thrust receiving mechanism 8 can efficiently generate dynamic pressures.
In addition, in the thrust receiving mechanism 8, the sliding surface 80a of each dynamic pressure piece 80 has a circular shape. The thrust receiving mechanism 8 can stably generate dynamic pressure at any position in the circumferential direction on the sliding surface 80a through movement relative to the movable scroll 42.
In addition, each sliding surface 80a is formed with substantially the same diameter as the revolving range of the side seal 7. For that reason, the thrust receiving mechanism 8 can more stably generate substantially the same dynamic pressure at any position in the circumferential direction on the sliding surface 80a through movement relative to the movable scroll 42.
Further, all the dynamic pressure grooves 83 formed on the sliding surface 80a having a circular shape are spiral grooves having substantially the same shape. Accordingly, the dynamic pressure piece 80 more easily generates substantially the same dynamic pressure in any of the dynamic pressure grooves 83.
In addition, each dynamic pressure piece 80 is formed in a cylindrical shape. Accordingly, a space outside the dynamic pressure piece 80, which is necessary to tilt the dynamic pressure piece 80, can be made narrow.
In addition, the dynamic pressure piece 80 is loosely fitted into the recess 3b of the inner casing 3. For that reason, while each dynamic pressure piece 80 is allowed to tilt or move in the axial direction, each dynamic pressure piece 80 abuts against an inner peripheral surface of the recess 3b, so that excessive tilting of each dynamic pressure piece 80 is restricted and the axial movement of each dynamic pressure piece 80 is guided.
In addition, the radial position of the dynamic pressure piece 80 is held by the movement restriction portion 90. For that reason, a situation where the tilting of the dynamic pressure piece 80 is hindered due to an outer peripheral surface of the dynamic pressure piece 80 excessively approaching the inner peripheral surface of the recess 3b, and a situation where excessive frictional force is generated due to the outer peripheral surface coming into sliding contact with the inner peripheral surface are prevented.
The embodiment of the present invention has been described above with reference to the drawings; however, specific configurations are not limited to the embodiment, and modifications or additions that are made without departing from the scope of the present invention are also included in the present invention.
For example, in the embodiment, the configuration in which 16 dynamic pressure pieces 80 are evenly spaced has been described; however, the present invention is not limited to this configuration, and the number or disposition of the dynamic pressure pieces 80 may be changed as appropriate as long as two or more dynamic pressure pieces 80 are provided. The same applies to the springs 81, the pins 82, the dynamic pressure grooves 83, and the recesses 3b of the inner casing 3.
In addition, in the embodiment, the configuration in which the thrust receiving mechanism 8 includes the inner casing 3 has been described; however, the present invention is not limited to this configuration, and each dynamic pressure piece 80, each spring 81, and each pin 82 may be configured to be held in a separate member from the inner casing or one member constituting the inner casing. For example, a configuration in which each dynamic pressure piece 80, each spring 81, and each pin 82 are held by a thrust plate disposed between the inner casing and the side seal 7, and instead of the inner casing, the thrust plate is included in the thrust receiving mechanism may be adopted.
In addition, in the embodiment, the configuration in which the dynamic pressure piece 80 is loosely fitted into the recess 3b and is surrounded by the inner peripheral surface of the recess 3b has been described; however, the present invention is not limited to this configuration, and the dynamic pressure piece 80 may be open in the radially outward direction instead of being loosely fitted into the recess 3b, namely, instead of being surrounded by a separate member.
In addition, in the embodiment, the configuration in which the dynamic pressure piece 80 has a cylindrical shape has been described; however, the present invention is not limited to this configuration, and the dynamic pressure piece 80 may have a tubular shape or an annular shape with a polygonal cross section or an elliptical cross section, or may have a columnar shape or a plate shape in which a through-hole is not formed, and the shape of the dynamic pressure piece 80 may be changed as appropriate.
In addition, in the embodiment, the pressing portion has been described as being the spring 81; however, the present invention is not limited thereto, and the pressing portion may be rubber or may be a high-pressure refrigerant, and may be changed as appropriate.
In addition, in the embodiment, the configuration in which the springs 81 are provided on the back portions of the respective dynamic pressure pieces 80 has been described; however, the present invention is not limited to this configuration, and one spring 81 may press the plurality of dynamic pressure pieces 80 toward the movable scroll 42 side.
In addition, in the embodiment, the configuration in which the movement restriction portion 90 is composed of the dynamic pressure piece 80 and the pin 82 has been described; however, the present invention is not limited to this configuration, and the dynamic pressure piece 80 may be configured to be fixed to the inner casing 3 via the spring 81, and the configuration of the movement restriction portion may be changed as appropriate. In addition, if the dynamic pressure piece 80 is configured to be fixed to the inner casing 3 via the spring 81, the radial movement of the dynamic pressure piece 80 may be restricted by loosely fitting the dynamic pressure piece 80 into the recess 3b. Further, it is not essential to provide the movement restriction portion.
In addition, in the embodiment, the tilting portion 91 has been described as being composed of the dynamic pressure piece 80 and the pin 82; however, the present invention is not limited thereto, and the dynamic pressure piece 80 may be configured to be fixed to the inner casing 3 via the spring 81 or an elastic member such as rubber, and the configuration of the tilting portion may be changed as appropriate. Further, it is not essential to provide the tilting portion.
In addition, in the embodiment, the configuration in which the rotation restriction portion 92 is key engagement between the dynamic pressure piece 80 and the pin 82 has been described; however, the present invention is not limited to this configuration, and the cross-sectional shape of the through-hole of the dynamic pressure piece and the cross-sectional shape of the pin may be an elliptical shape or may be a polygonal shape, and the shape may be changed as appropriate as long as rotation can be prevented. Further, it is not essential to provide the rotation restriction portion.
In addition, in the embodiment, the configuration in which the recesses 3b of the inner casing 3 do not communicate with each other has been described; however, the present invention is not limited to this configuration, and the recesses 3b may communicate with each other.
In addition, in the embodiment, the configuration for generating dynamic pressure has been described as being a dynamic pressure groove having a spiral shape; however, the present invention is not limited to this configuration, and the configuration may be a dimple or may be a Rayleigh step, and may be changed as appropriate as long as the configuration can generate dynamic pressure.
In addition, in the embodiment, the mode in which the thrust receiving mechanism 8 is applied to the scroll compressor C used in an air conditioning system of an automobile or the like has been described; however, the present invention is not limited to this mode, and may be applied to, for example, a scroll expander-compressor or the like in which an expander and a compressor are integrally provided as long as the scroll expander-compressor is a rotating machine including an eccentric mechanism.
In addition, in the embodiment, the fluid present in the spaces inside and outside the sliding surface 80a of the thrust receiving mechanism 8 may be any of gas, liquid, and a mixture of gas and liquid.
In addition, in the embodiment, the side seal having the sliding surface that undergoes relative sliding and the dynamic pressure piece have been described as being made of resin and metal, respectively; however, the materials of the sliding components may be freely selected depending on the usage environment or the like.
In addition, in the embodiment, the mode in which the side seal 7 slides relative to the thrust receiving mechanism 8 has been provided as an example; however, the back surface of the movable scroll may directly slide relative to the thrust receiving mechanism 8.

{REFERENCE SIGNS LIST}

4: Scroll compression mechanism
7: Side seal
7a: Sliding surface
8: Thrust receiving mechanism
41: Fixed scroll
42: Movable scroll
80: Dynamic pressure piece (dynamic pressure generation portion)
80a: Sliding surface
81: Spring (pressing portion)
82: Pin
83: Dynamic pressure groove
90: Movement restriction portion
91: Tilting portion
92: Rotation restriction portion
C: Scroll compressor

Claims

A thrust receiving mechanism provided on a back surface of a movable scroll that slides relative to a fixed scroll while rotating eccentrically, and configure for generating a dynamic pressure on the back surface of the movable scroll, comprising:
a plurality of dynamic pressure generation portions; and

pressing portions that press the dynamic pressure generation portions.
The thrust receiving mechanism according to claim 1,
wherein the plurality of dynamic pressure generation portions are disposed in an annular shape at spacings in a circumferential direction.
The thrust receiving mechanism according to claim 1,
wherein the pressing portions are provided on back portions of the respective dynamic pressure generation portions.
The thrust receiving mechanism according to claim 1, further comprising:
movement restriction portions configured for restricting the dynamic pressure generation portion from moving toward a movable scroll side by a predetermined distance or more.
The thrust receiving mechanism according to claim 1, further comprising:
tilting portions configured for allowing the dynamic pressure generation portion to tilt according to a tilting of the movable scroll.
The thrust receiving mechanism according to claim 1, further comprising:
rotation restriction portions configured for restricting a rotation of the dynamic pressure generation portion.
The thrust receiving mechanism according to any one of claims 1 to 6,
wherein each of the dynamic pressure generation portions has a sliding surface having a circular shape that slides relative to the movable scroll, and

the sliding surface is provided with a plurality of dynamic pressure grooves formed to be separated from each other in a circumferential direction.