Scroll compressor

Abstract

In a scroll compressor, breakage of a spiral end portion of a spiral wall (10c, 11c) of a scrolls is prevented. [Solving means] In a scroll compressor including: a fixed scroll (10) including an end plate (10a) and a spiral wall (10c) extending upright from the end plate (10a); an orbiting scroll (11) including an end plate (11a) and a spiral wall (11c) extending upright from the end plate (11a); and a drive shaft (8) configured to transmit a rotational power to the orbiting scroll (11), and configured to compress a compressed fluid by an orbital motion of the orbiting scroll (11), an extending portion (113) which does not come into contact with the spiral wall (10c) of the fixed scroll (10) is provided so as to extend from a spiral end portion (112), which corresponds to a terminal end of a wall surface (compression forming portion (111)) which forms a compression chamber (15) on a spiral wall (11c) of the orbiting scroll (11).

Claims

1. A scroll compressor comprising: a fixed scroll including an end plate and a first spiral wall extending upright from the end plate; an orbiting scroll arranged so as to oppose the fixed scroll and including an end plate and a second spiral wall extending upright from the end plate; and a drive shaft configured to transmit a rotational power to the orbiting scroll, the orbiting scroll making an orbital motion and compressing a compressed fluid by moving a compression chamber formed by the fixed scroll and the orbiting scroll toward a center side while reducing a volume thereof, wherein the second spiral wall is provided with an extending portion which does not come into contact with the first spiral wall, the extending portion being from a spiral end portion at a terminal end of a wall surface that forms the compression chamber, and wherein a height of the extending portion from the end plate is gradually reduced and terminates in a face with a height greater than zero.

2. The scroll compressor according to claim 1, wherein the extending portion forms a non-contact state with respect to the first spiral wall by retracting an inner wall surface thereof from the first spiral wall opposing thereto.

3. The scroll compressor according to claim 2, wherein the height of the extending portion from the end plate is set to be lower than a height of the spiral wall.

4. The scroll compressor according to claim 3, wherein a height of a transition part from the spiral end portion to the extending portion is gradually reduced.

5. The scroll compressor according to claim 4, wherein a suction port configured to introduce the compressed fluid to the compression chamber is provided on a peripheral wall of the fixed scroll facing the extending portion.

6. The scroll compressor according to claim 3, wherein a suction port configured to introduce the compressed fluid to the compression chamber is provided on a peripheral wall of the fixed scroll facing the extending portion.

7. The scroll compressor according to claim 1, wherein a height of a transition part from the spiral end portion to the extending portion is gradually reduced.

8. The scroll compressor according to claim 7, wherein a suction port configured to introduce the compressed fluid to the compression chamber is provided on a peripheral wall of the fixed scroll facing the extending portion.

9. The scroll compressor according to claim 1, wherein a suction port configured to introduce the compressed fluid to the compression chamber is provided on a peripheral wall of the fixed scroll facing the extending portion.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a cross-sectional view illustrating an example of an overall configuration of a scroll compressor according to the present invention.

(2) FIG. 2A is a perspective view illustrating a fixed scroll used in the scroll compressor of the present invention, and FIG. 2B is a perspective view illustrating an orbiting scroll used in the scroll compressor according to the present invention.

(3) FIG. 3A is a drawing of the fixed scroll used in the scroll compressor according to the present invention viewing from a spiral wall side (a spiral wall of the orbiting scroll is illustrated in an imaginary line), FIG. 3B is a drawing of the orbiting scroll used M the scroll compressor according to the present invention when viewing from an end plate side (the spiral wall of the orbiting scroll is illustrated by a broken line).

(4) FIG. 4 is an explanatory drawing illustrating a relationship between the fixed scroll and the orbiting scroll.

(5) FIG. 5 is a perspective view illustrating a portion in the vicinity of a spiral end portion of the orbiting scroll.

(6) FIG. 6 is a drawing illustrating an example of a configuration in which an inner wall surface of an extending portion provided on the orbiting scroll is retracted from a spiral wall of the fixed scroll opposing thereto.

(7) FIG. 7 is an enlarged perspective view illustrating a connecting portion of an end plate with the spiral wall and the extending portion in the vicinity of the spiral end portion of the orbiting scroll.

(8) FIG. 8 is a drawing illustrating an example of a configuration in which an outer wall surface of the spiral wall of the fixed scroll opposing the extending portion provided on the orbiting scroll is retracted.

(9) FIG. 9A is a drawing illustrating a state in which a fixed scroll and an orbiting scroll of the related art are combined (a spiral wall of the orbiting scroll is illustrated by an imaginary line), and FIG. 9B is an enlarged plan view illustrating a portion in the vicinity of a spiral end portion of the orbiting scroll.

DETAIL DESCRIPTION OF INVENTION

(10) Hereinafter, an embodiment of a scroll compressor according to the present invention in a case where an electric compressor including a compression mechanism and an electric motor integrated with each other is used will be described with reference to the attached drawings.

(11) FIG. 1 illustrates an electric compressor 1 suitable for a refrigeration cycle using a refrigerant as a working fluid. The electric compressor 1 is provided with an electric motor 3 in a housing 2 formed of aluminum alloy on the right side in the drawing, and a compression mechanism 4 configured to be driven by the electric motor on the left side in the drawing. In FIG. 1, the right side of the drawing corresponds to the front side of the electric compressor, and the left side of the drawing corresponds to the rear side of the electric compressor.

(12) The housing 2 is provided with a drive shaft 8 rotatably supported by a block member (axially supporting member) 5 fixed to an inside thereof at the midpoint thereof and a front wall portion 2a via bearings 6, 7.

(13) A motor accommodating space 31 which accommodates the electric motor 3 is formed in the housing 2 on the front side of the block member 5, and a stator 33, which constitutes part of the electric motor 3, is accommodated therein. The stator 33 includes an iron core 34 having a cylindrical shape and a coil 35 wound therearound, and is fixed to an inner surface of the housing 2. A rotor 36 composed of magnets and rotatably accommodated inside the stator 33 is fixedly mounted on the drive shaft 8, and the rotor 36 is configured to be rotated by a rotational magnetic force formed by the stator 33.

(14) The compression mechanism 4 is a scroll type including a fixed scroll 10 and an orbiting scroll 11 arranged so as to oppose the fixed scroll 10. As also illustrated in FIG. 2 A, FIG. 3A, and FIG. 4, the fixed scroll 10 includes a disc-shaped end plate 10a fixed to a rear portion inside the housing 2, a cylindrical outer peripheral wall 10d provided over an entire circumference along an outer edge of the end plate 10a and so as to extend toward the front, and a spiral-shaped spiral wall 10c provided so as to extend from the end plate 10a toward the front via a connecting portion 10b inside the outer peripheral wall 10d.

(15) As also illustrated in FIG. 2B, FIG. 3B, and FIG. 4, the orbiting scroll 11 includes a disc-shaped end plate 11a and a spiral-shaped spiral wall 11c extending rearward from the endplate 11a via a connecting portion 11b, and an eccentric shaft 8a provided at a rear end portion of the drive shaft 8 eccentrically with respect to an axial center of the drive shaft 8 is coupled to a boss portion 11d formed on a rear surface of the end plate 11a via a bush 12 and a bearing 13 and is supported so as to allow an orbital motion about an axial center of the drive shaft 8.

(16) The fixed scroll 10 and the orbiting scroll 11 engage with each other by the spiral walls 10c, 11c thereof, and distal ends of the spiral walls 10c, 11c in the extending directions oppose each other with a minute clearance with respect to inner surfaces of the end plates 10a and 11a. Therefore, a compression chamber 15 is defined in a space surrounded by the end plate 10a and the spiral wall 10c of the fixed scroll 10 and the end plate lie and the spiral wall 11c of the orbiting scroll 11.

(17) A thin-plate-shaped annular thrust race 16 is held between the outer peripheral wall 10d of the fixed scroll 10 and the block member 5, and the fixed scroll 10 and the block member 5 abut against each other via the thrust race 16.

(18) The thrust race 16 is formed of a material superior in wear resistance, is formed into a size having an outer edge shape which matches the outer edge shape of an end surface of the block member 5, and includes a hole at a center thereof to allow an insertion of the boss portion 11d of the orbiting scroll 11 therethrough. The fixed scroll 10, the thrust race 16, and the block member 5 are positioned and fixed by a positioning pin 9.

(19) The block member 5 is formed into a cylindrical shape having an inner surface with a diameter increasing step-by-step as it goes toward the compression mechanism 4 and includes, from the front side farthest from the thrust race 16, a seal accommodating portion 22 configured to accommodate a seal member 21 configured to seal between the block member 5 and the drive shaft 8, a bearing accommodating portion 23 configured to accommodate the bearing 6, a weight accommodating portion 24 configured to accommodate a balance weight 19 which rotates in association with a rotation of the drive shaft 8 integrally with the bush 12, and an Oldham accommodating portion 25 configured to accommodate an Oldham's ring 18 as a rotation preventing mechanism disposed between the end surface of the block member 5 and the end plate 11a of the orbiting scroll 11.

(20) Therefore, the orbiting scroll 11 is configured to make an orbital motion with respect to the axial center of the drive shaft 8 while being restricted from a rotation by the Oldham's ring 18 against a rotating force generated in association with the rotation of the drive shaft 8.

(21) The outer peripheral wall 10d of the fixed scroll 10 described above is provided with an suction port 26 configured to intake a refrigerant introduced through an inlet port 40, which will be described later, via the motor accommodating space 31, and a discharge chamber 28 to which refrigerant gas compressed by the compression chamber 15 is discharged via a discharge hole 27 formed at a substantially center of the fixed scroll 10 is defined in the housing on the rear side of the fixed scroll 10 by a rear wall 2b of the housing 2. The refrigerant gas discharged into the discharge chamber 28 has oil separated here to some extent, and the separated oil is pumped to an external refrigerant circuit from a discharge port, which is not illustrated. The separated oil and the refrigerant containing oil are also accumulated in an accumulating chamber 32 provided under the discharge chamber 28.

(22) The inlet port 40 configured to intake refrigerant gas is formed on a side surface of the housing 2, which faces the motor accommodating space 31, and the refrigerant flowed from the inlet port 40 into the motor accommodating space 31 is introduced to the suction port 26 via a gap between the stator 33 and the housing 2, a passage between the block member 5 and the housing 2, which is not illustrated, and a gap formed between the fixed scroll 10 and the housing 2.

(23) Reference numeral 50 denotes an inverter accommodating chamber configured to accommodate an inverter drive circuit not illustrated, which is formed on an upper portion of the housing 2 and configured to control power distribution of the electric motor 3, in which the inverter drive circuit and the stator 33 are electrically connected via a relay terminal, which is not illustrated, to supply power from the inverter drive circuit to the electric motor 3.

(24) Therefore, when the electric motor 3 rotates and thus the drive shaft 8 rotates, the orbiting scroll 11 rotates about the eccentric shaft 8a in the compression mechanism 4. Therefore, the orbiting scroll 11 orbits around the axial center of the fixed scroll 10. At this time, the orbiting scroll 11 is prevented from rotating by a rotation preventing mechanism composed of the Oldham's ring 18, and thus only the orbital motion is allowed.

(25) With the orbital motion of the orbiting scroll 11, the compression chamber 15 moves from an outer peripheral side of the spiral walls 10c, 11c of both of the scrolls toward the center while gradually reducing the volume thereof. Therefore, the refrigerant gas taken from the suction port 26 into the compression chamber 15 is compressed, the compressed refrigerant gas is discharged into the discharge chamber 28 via the discharge hole 27 formed in the end plate 10a of the fixed scroll 10, and then is delivered to the external refrigerant circuit via a discharge port, which is not illustrated.

(26) In the electric compressor 1 having configuration as described above, the spiral wall 10c of the fixed scroll 10 and the spiral wall 11c of the orbiting scroll 11 include compression forming portions 101, 111 for forming the compression chamber 15 and spiral end portions 102, 112 which correspond to the terminal ends of the wall surfaces for forming the compression chamber 15. The spiral wall 11c of the orbiting scroll 11 is further provided with an extending portion 113 extending from the spiral end portion 112 as illustrated in FIG. 5.

(27) The compression forming portions 101, 111 of the spiral walls 10c, 11c of the respective scrolls are formed to have a curved surface along an involute curve from starting points of spirals located at a center portion of the scrolls to the spiral end portions 102, 112, respectively. The spiral end portions 102, 112 are portions which come into contact with the spiral walls of the counterpart at the outermost side of the spiral walls 10c, 11c (end points of the contact points which contribute to the compression), and are positions where the closing of the compression chamber 15 starts.

(28) The extending portion 113 formed on the orbiting scroll 11 extends so as to avoid contact with the spiral wall 10c of the fixed scroll 10 and can be, and can not be formed along the involute curve. In this example, as illustrated in FIG. 6, the extending portion 113 and the spiral wall 10c of the fixed scroll 10 are kept out of contact by retracting the inner wall surface of the extending portion 113 from the spiral wall 10c of the fixed scroll 10 opposing thereto.

(29) The extending portion 113 is set to have a height from the endplate 11a lower than the height of the spiral wall 11c. In this example, a height of a transition part from the spiral end portion 112 to the extending portion 113 from the end plate is set to gradually reduce.

(30) The extending portion 113 is provided on a portion opposing the suction port 26 provided on a peripheral wall of the fixed scroll 10, and the compressed fluid introduced via the suction port 26 flows along the periphery of the extending portion 113 and introduced into the compression chamber 15.

(31) In the configuration described above, when the orbiting scroll 11 orbits around the axial center of the fixed scroll 10 and the spiral end portion 112 comes into contact with the spiral wall 10c of the fixed scroll 10, the compressed fluid is trapped in the compression chamber 15, and the compression of the trapped compressed fluid starts. However, even though the spiral end portion 112 comes into contact with the spiral wall 10c of the fixed scroll 10 and a contact load acts on radially outside of the spiral end portion 112, the spiral wall 11c of the orbiting scroll 11 is provided with the extending portion 113, which does not come into contact with the spiral wall 10c of the fixed scroll 10, from the spiral end portion 112, and thus receives the contact load acting so as to shear the spiral wall 11c from the end plate 11a not only by a connecting portion 111b connecting the spiral wall 11c extending in the compression forming portion 111 to the end plate 11a, but also by a connecting portion 113b connecting the extending portion 113 to the end plate 11a as illustrated in FIG. 7. Therefore, a surface area which supports the shear load is sufficiently secured in the vicinity of the spiral end portion 112, and the shear stress in the vicinity of the spiral end portion 112 can be reduced, so that the breakage of the spiral wall of the spiral end portion 112 is prevented.

(32) In the configuration described above, since a non-contact state with respect to the spiral wall 10c of the fixed scroll 10 is achieved by retracting the inner wall surface of the extending portion 113 from the spiral wall 10c of the fixed scroll 10 facing thereto, a reduction in thickness of the spiral wall 10c of the fixed scroll 10 is no longer necessary and the strength of the spiral wall 10c of the fixed scroll 10 can be secured.

(33) In addition, since the extending portion 113 is formed so that the height of the transition part from the spiral end portion 112 from the end plate 11a is gradually reduced, the spiral wall 11c which tends to tilt outward by a cutting resistance at the time of processing is supported and is prevented from being deformed, and in addition, an increase in weight of the orbiting scroll 11 can be restrained while securing the contact surface area with respect to the endplate 11a.

(34) In the case of processing the spiral wall of the scroll with an end mill, when a portion to be processed of the spiral wall is processed by the tool, the portion to be processed is pressed against the tool due to the cutting resistance, and hence is perpendicular to the end plate so as to extend along the tool. However, after the tool has passed, such a phenomenon that the spiral wall is inclined inward due to elasticity of the spiral wall itself which is released from the cutting resistance (so-called spring back) occurs. Such a phenomenon is negligible because both sides of the portion to be processed are supported by a spiral wall 111 while processing portions other than the spiral end portion. However, in processing of the spiral end portion 112 of the spiral wall having the structure of the related art, the spiral wall is deformed radially outward due to the cutting resistance generated at the time of processing because the spiral wall 111 exists only on one side of the spiral end portion, and after the processing, tends to incline inward due to elasticity of the spiral wall itself, and thus there is a concern that a problem of breakage of the spiral end portion may occur when the spiral walls come into contact with each other at that portion.

(35) Accordingly, by gradually reducing the height of the extending portion from the end plate, the height of the extending portion is secured at a portion in the vicinity of the spiral end portion to support the spiral wall which tends to tilt outward due to the cutting resistance at the time of processing and prevent deformation thereof. In contrast, at a portion far from the spiral end portion, since the degree of contribution to the effect of preventing the inclination caused by the cutting resistance of the spiral end portion is low, the height of the extending portion which does not need to be high is set to be low, so that an increase in weight of the scroll can be avoided.

(36) In addition, since the height of the extending portion from the end plate is gradually reduced from the spiral end portion, even when the suction port 26 configured to introduce the compressed fluid to the compression chamber 15 is provided on the outer peripheral wall 10d of the fixed scroll 10 facing the extending portion 113, an increase in intake resistance of the compressed fluid can be avoided and thus the provision of the extending portion 113 does not cause any problem.

(37) Although an example of forming the non-contact state by retracting the inner wall surface of the extending portion 113 from the spiral wall 10c of the fixed scroll 10 opposing thereto has been described in the configuration described above, the non-contact state can be achieved by retracting the outer wall surface of the spiral wall 10c of the fixed scroll 10 opposing the extending portion 113 as illustrated in FIG. 8.

(38) In this configuration, a reduction in thickness of the extending portion 113 is no longer necessary, and the strength of the extending portion 113 can be secured.

(39) In the configuration described above, an example of configuration in which the extending portion 113 is formed from the spiral end portion 112 on the spiral wall 11c of the orbiting scroll 11 has been described. Instead of, or in addition to this configuration, however, an extending portion can be formed on the spiral end portion 102 of the spiral wall 10c of the fixed scroll 10.

(40) In addition, although an example in which the configuration described above is adopted to the scroll electric compressor has been described, the same configuration can also be adopted in the scroll compressor in which a drive force is transmitted from the outside.

REFERENCE SIGNS LIST

(41) 1 electric compressor 8 drive shaft 10 fixed scroll 10a end plate 10c spiral wall 11 orbiting scroll 11a end plate 11c spiral wall 15 compression chamber 26 suction port 101, 111 compression forming portion 102, 112 spiral end portion 113 extending portion