JP2007270763A - Scroll type fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a delivery flow rate and compression efficiency of a compressed fluid, by minimizing a clearance between a lap part of a fixed scroll and a lap part of a turning scroll. <P>SOLUTION: The fixed scroll 3 is installed in a casing 1, and the turning scroll 12 is turnably installed in a state of it being opposed to the fixed scroll 3. A rotation preventive mechanism 21 by ball guides 22 and 23 and a ball 24, is arranged between the casing 1 and the turning scroll 12. A turning radius S1 determined by the rotation preventive mechanism 21 is set larger than a turning radius S2 determined by the lap parts 3B and 12B of the respective scrolls 3 and 12 (S1>S2). Thus, the turning scroll 12 is turnably moved in a state of contacting the mutual lap parts 3B and 12B. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a scroll fluid machine suitable for use in an air compressor, a vacuum pump, or the like.

  Generally, a scroll type fluid machine is capable of turning to the front end side of a drive shaft while facing a fixed scroll provided in a casing, a fixed scroll provided in the casing, and a drive shaft rotatably provided in the casing. The orbiting scroll provided in the. At this time, each of the fixed scroll and the orbiting scroll has a spiral wrap portion, and a plurality of compression chambers are defined between the wrap portions. As a conventional technique, an anti-rotation mechanism for preventing the rotation of the orbiting scroll is provided between the casing and the back surface of the orbiting scroll, and the anti-rotation mechanism is fixed to the fixed scroll and the orbiting scroll so as to face each other. There is a known one constituted by a pair of ball guides having an annular guide groove and a ball sandwiched between the guide grooves of these ball guides (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-210647

  By the way, in the scroll type fluid machine according to the prior art, a crank mechanism having a predetermined eccentricity R is provided at the tip of the drive shaft, and the turning radius of the orbiting scroll is determined using the eccentricity R of the crank mechanism. However, in practice, a centrifugal force acts on the orbiting scroll in addition to the play Δ in the orbiting bearing that supports the crank mechanism. For this reason, the orbiting scroll is orbiting at an orbiting radius S0 (S0 = R + Δ), which is obtained by adding the eccentric amount R and the play amount Δ. At this time, in order to prevent the side surface of the wrap portion of the orbiting scroll from coming into contact with the side surface of the wrap portion of the fixed scroll, the orbiting radius S0 is larger than the orbiting radius S2 determined by the dimension with which the wrap portion of each scroll contacts. Was set to a value. Further, the turning radius S1 determined by the ball guide and the ball is set to a value (S1 <S2) smaller than the turning radius S2 determined by the lap portion of each scroll.

  Recently, however, the weight of the orbiting scroll has been reduced, and the centrifugal force acting on the orbiting scroll has been reduced. On the other hand, since the orbiting scroll is pressed toward the casing by the internal pressure of the compression chamber, the force for narrowing the distance between the pair of ball guides (force for holding the ball) is stronger than the centrifugal force. For this reason, the orbiting scroll orbits with the orbiting radius S1 determined by the ball guide and the ball, and there is a tendency that a gap is generated between the wrap portion of the fixed scroll and the wrap portion of the orbiting scroll. As a result, there is a problem that the compressed fluid leaks from the compression chamber and the discharge flow rate and compression efficiency of the compressed fluid are reduced.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to minimize the gap between the wrap portion of the fixed scroll and the wrap portion of the orbiting scroll so that the discharge flow rate and compression of the compressed fluid can be reduced. It is an object of the present invention to provide a scroll type fluid machine that can improve efficiency.

  In order to solve the above-described problems, the present invention provides a casing, a fixed scroll provided with a spiral wrap portion provided on the casing, a drive shaft rotatably provided on the casing, and a swing on the drive shaft. The orbiting scroll provided with a spiral wrap portion defining a plurality of compression chambers between the fixed scroll and the wrap portion of the fixed scroll, and the orbiting scroll provided between the casing side and the orbiting scroll. A rotation prevention mechanism for preventing rotation, the rotation prevention mechanism being fixed to the orbiting scroll at a position facing the fixed ball guide and a fixed ball guide having an annular guide groove fixed to the casing side. A movable ball guide having a guide groove, and a ball sandwiched between the guide groove of the fixed ball guide and the guide groove of the movable ball guide. It applied to crawl type fluid machine.

  A feature of the configuration adopted by the invention of claim 1 is that the turning radius obtained by the fixed ball guide, the movable ball guide and the ball is S1, and the turning determined by the side surface of the wrap portion of the fixed scroll and the turning scroll. When the radius is S2, S1> S2.

  According to a second aspect of the present invention, a processing layer by surface treatment is provided on a side surface of at least one of the orbiting scroll and the fixed scroll.

  According to a third aspect of the present invention, when the total value of the thickness dimension of the processing layer of the fixed scroll and the thickness dimension of the processing layer of the orbiting scroll is δ, the relationship between the orbiting radii S1 and S2 is S2 + δ> S1. > S2 is set.

  According to a fourth aspect of the present invention, a crank mechanism having an eccentric amount is provided between the orbiting scroll and the drive shaft, and the eccentric amount of the crank mechanism includes a play larger than the total value δ of the thickness dimensions of the processing layers. It is set as the structure which has.

  According to the first aspect of the present invention, since the turning radius S1 determined by the ball guide and the ball is larger than the turning radius S2 determined by the side surface of the lap portion of each scroll, when the turning scroll makes a turning motion along the turning radius S1. The side surface of each scroll lap part contacts. At this time, even if the turning radius is slightly deviated in the vicinity of the turning radius S1, the amount of movement of the turning scroll in the axial direction (thrust direction) toward the fixed scroll is small. Therefore, the force acting in the radial direction (radial direction) of the turning scroll Is weak. For this reason, even if the orbiting scroll orbits while the lap portions of the scrolls are in contact with each other, no significant mechanical loss occurs. On the other hand, since the gap between the wrap portions of each scroll can be made as small as possible, leakage of the compressed fluid from the compression chamber due to this gap can be prevented, and the discharge flow rate and compression efficiency of the compressed fluid can be improved. .

  According to the invention of claim 2, since the treatment layer by the surface treatment is provided on the side surface of at least one of the orbiting scroll and the fixed scroll, for example, each of the scrolls is provided by providing a hard treatment layer by anodizing treatment. Even if the side surface of the lap portion is in contact with each other, the wear can be suppressed and the durability can be enhanced.

  According to the invention of claim 3, the turning radius S1 determined by the ball guide and the ball is compared with a value (S2 + δ) obtained by adding the turning radius S2 determined by the lap portion of each scroll and the total value δ of the thickness dimension of the treatment layer. (S2 + δ> S1). For this reason, even when the wrap portion of the fixed scroll and the lap portion of the orbiting scroll come into contact with each other and wear occurs, the wear range can be kept within the treatment layer range of the wrap portion, and wear exceeding the treatment layer can be prevented. It can be suppressed and reliability can be improved.

  According to the invention of claim 4, since the eccentric amount of the crank mechanism has a play larger than the total value δ of the thickness dimension of the processing layer, the crank mechanism has a turning radius S0 obtained by adding the play to the eccentric amount. The orbiting scroll can be turned. However, since the amount of play becomes uncertain, the actual turning radius of the orbiting scroll is not determined by the turning radius S0 by the crank mechanism, but by the turning radius S1 by the ball guide or the like and the turning radius S2 by the lap portion. Therefore, by making the turning radius S1 by the ball guide or the like larger than the turning radius S2 by the lap portion (S1> S2), it is possible to make the orbiting scroll turn while the wrap portions are in contact with each other.

  Hereinafter, a scroll type air compressor will be described as an example of a scroll type fluid machine according to an embodiment of the present invention, and will be described in detail with reference to FIGS.

  In the figure, reference numeral 1 denotes a bottomed cylindrical casing which is open at one end in the axial direction. The casing 1 includes an annular plate portion 1A which is located at the other axial end side and forms the bottom of the casing 1, and an annular plate portion 1A. A boss portion 1B provided on the center side and containing a main bearing 8 to be described later, a cylindrical portion 1C extending from the outer peripheral side of the annular plate portion 1A toward one end side in the axial direction, and provided at the tip of the cylindrical portion 1C. And a flange portion 1D to which the fixed scroll 3 is attached. And the electric motor 2 is attached to the casing 1 at the other end side in the axial direction of the annular plate portion 1A.

  Reference numeral 3 denotes a fixed scroll attached to the casing 1, and the fixed scroll 3 is erected on a surface of the end plate 3 </ b> A and a disc-shaped end plate 3 </ b> A disposed so as to coincide with an axis of a drive shaft 7 to be described later. The spiral wrap portion 3B is formed, and a cylindrical portion 3C protruding in the axial direction toward the casing 1 from the outer edge side of the end plate 3A. A string-like tip seal 4 is attached to the tooth tip of the lap portion 3B of the cylindrical portion 3C of the fixed scroll 3. Further, a plurality of bolt insertion holes 3 </ b> D are formed in the cylindrical portion 3 </ b> C of the fixed scroll 3 at positions facing the flange portion 1 </ b> D of the casing 1. A fixing bolt 5 is inserted into the bolt insertion hole 3D, and the fixing bolt 5 is screwed to the flange portion 1D of the casing 1. Thereby, the fixed scroll 3 is fixed to the flange portion 1 </ b> D using the fixing bolt 5.

  Further, the fixed scroll 3 is formed using, for example, aluminum, and the end plate 3A and the wrap portion 3B are subjected to an anodizing treatment as a surface treatment. Thereby, the hard processing layer 6 having a thickness dimension δ1 of about 10 μm to 50 μm, for example, is formed on the side surface of the wrap 3B.

  A drive shaft 7 is rotatably provided in the boss portion 1B of the casing 1 via a main bearing 8. The drive shaft 7 is screwed to the rotary shaft 2A of the electric motor 2 at the base end side, and is electrically driven. The motor 2 is rotationally driven. Further, a large-diameter stepped portion 7 </ b> A is formed on the proximal end side of the drive shaft 7.

  Reference numeral 9 denotes an eccentric bush 9 as a crank mechanism attached to the front end side of the drive shaft 7, and the eccentric bush 9 is formed in a substantially cylindrical shape. A drive shaft hole 9A that accommodates the distal end side of the drive shaft 7 is formed on the base end side of the eccentric bush 9, and an annular shape that protrudes toward the drive shaft 7 is formed around the drive shaft hole 9A. The convex portion 9B is formed.

  On the other hand, a swivel bearing hole 9C that accommodates a swivel bearing 14 to be described later is formed on the distal end side of the eccentric bush 9, and the swivel bearing hole 9C is eccentric with a certain amount of eccentricity R with respect to the drive shaft hole 9A. However, for example, the clearance between the main bearing 8 and the slewing bearing 14, the clearance between the main bearing 8 and the boss portion 1B, and the clearance between the slewing bearing 14 and the boss portion 12C are large. Thereby, the eccentric amount R is provided with a play amount Δ that is larger than the total value δ of the thickness dimensions δ1 and δ2 of the processing layers 6 and 15.

  The eccentric bush 9 is fixed to the tip of the drive shaft 7 using a retaining ring 10 and a bolt 11. Accordingly, the main bearing 8 is sandwiched between the convex portion 9B of the eccentric bush 9 and the stepped portion 7A of the drive shaft 7, so that the drive shaft 7 can rotate without being inclined with respect to the casing 1. ing.

  Reference numeral 12 denotes a orbiting scroll provided on the front end side of the drive shaft 7 so as to be opposed to the fixed scroll 3, and the orbiting scroll 12 is provided with a disc-shaped end plate 12A and a front surface side of the end plate 12A. The wrap portion 12 </ b> B that is erected in a standing manner is roughly configured, and a tip seal 13 is attached to the tooth tip of the wrap portion 12 </ b> B in the same manner as the fixed scroll 3. Further, a cylindrical boss portion 12C is projected from the back side of the end plate 12A so as to be located at the central portion thereof. A slewing bearing 14 is attached to the outer peripheral side of the boss portion 12C, and the slewing bearing 14 is inserted into the slewing bearing hole 9C of the eccentric bush 9. At this time, a slight gap is formed between the swing bearing 14 and the swing bearing hole 9C. Thereby, the orbiting scroll 12 can be displaced in the axial direction together with the orbiting bearing 14.

  Further, the orbiting scroll 12 is formed using, for example, aluminum, and the end plate 12A and the lapping portion 12B are subjected to anodizing treatment as a surface treatment. Thereby, the hard processing layer 15 having a thickness dimension δ2 of about 10 μm to 50 μm, for example, is formed on the side surface or the like of the wrap 12B.

  Further, the orbiting scroll 12 is disposed so as to overlap with the wrap portion 3B of the fixed scroll 3 by 180 degrees, for example, and a plurality of compression chambers 16, 16... Are defined between the wrap portions 3B, 12B. Is done. During the operation of the scroll type air compressor, the orbiting scroll 12 is swung by the drive shaft 7 while the air is sucked into the outer compression chamber 16 from the suction port 17 provided on the outer periphery side of the fixed scroll 3. During the eccentric rotation, the compressed air is sequentially compressed in each compression chamber 16, and finally compressed air is discharged from the central compression chamber 16 to the outside through a discharge port 18 provided at the center of the fixed scroll 3.

  Reference numeral 19 denotes, for example, three orbiting scroll side accommodation holes (only one is shown) provided on the back side of the end plate 12A. The orbiting scroll side accommodation hole 19 has a circular bottom with a recess recessed on the back side of the end plate 12A. Consists of holes. In addition, the three orbiting scroll side accommodation holes 19 are arranged, for example, at positions (at every 120 degrees) that are located around the boss portion 12C and are equally spaced in the circumferential direction. And the movable ball guide 23 of the rotation prevention mechanism 21 mentioned later is accommodated in the turning scroll side accommodation hole 19.

  Reference numeral 20 denotes, for example, three casing-side accommodation holes (only one is shown) provided in the annular plate portion 1A of the casing 1, and the casing-side accommodation holes 20 are located in the cylindrical portion 1C of the casing 1 and are annular plates. It is comprised by the circular bottomed hole recessed by the surface side of the part 1A. Further, the three casing-side accommodation holes 20 are opposed to the respective orbiting scroll-side accommodation holes 19 and are arranged at positions (at every 120 degrees) that are located around the boss portion 1B and are equally spaced in the circumferential direction. ing. And in the casing side accommodation hole 20, the fixed ball guide 22 of the rotation prevention mechanism 21 mentioned later is accommodated.

  Reference numeral 21 denotes three anti-rotation mechanisms provided between the casing-side accommodation hole 20 of the casing 1 and the orbiting scroll-side accommodation hole 19 of the orbiting scroll 12. The anti-rotation mechanism 21 includes ball guides 22 and 23, which will be described later. And a ball coupling mechanism including a ball 24 and the like.

  Reference numeral 22 denotes a fixed ball guide attached to the casing side accommodation hole 20 of the casing 1, and the fixed ball guide 22 is formed in a substantially disc shape and is fitted into the casing side accommodation hole 20 forming a circular hole. An annular guide groove 22 </ b> A for guiding the ball 24 is recessed on the surface of the fixed ball guide 22 facing the movable ball guide 23.

  Here, the guide groove 22 </ b> A has an arc-shaped cross section having a slightly larger curvature than the outer surface of the ball 24. Then, the ball 24 rolls along the deepest portion of the guide groove 22A. For this reason, the radius of the circle connecting the deepest portion of the guide groove 22 </ b> A substantially coincides with the track radius E of the ball 24.

  Reference numeral 23 denotes a movable ball guide attached to the orbiting scroll side accommodation hole 19 of the orbiting scroll 12, and the movable ball guide 23 is formed in a substantially disc shape like the fixed ball guide 22 and forms a circular hole. It is fitted in the accommodation hole 19. An annular guide groove 23 </ b> A for guiding the ball 24 is recessed on the surface of the movable ball guide 23 that faces the fixed ball guide 22.

  Here, the guide groove 23A has an arc-shaped cross section having a slightly larger curvature than the outer surface of the ball 24, in substantially the same manner as the guide groove 22A. Then, the ball 24 rolls along the deepest portion of the guide groove 23A. For this reason, the radius of the circle connecting the deepest portion of the guide groove 23 </ b> A substantially coincides with the track radius E of the ball 24.

  A ball 24 is sandwiched between the two ball guides 22 and 23 so as to be able to roll. The ball 24 is formed of a steel material and rolls along the guide grooves 22A and 23A of the ball guides 22 and 23. Move. Thereby, the rotation prevention mechanism 21 supports the thrust load acting on the orbiting scroll 12 and prevents the orbiting scroll 12 from rotating.

  Reference numerals 25 and 26 denote cover members attached to the opposing surface sides of the respective ball guides 22 and 23. The cover members 25 and 26 are formed in a substantially cylindrical shape and surround the ball 24 in a state of surrounding the ball 24. It is firmly fixed to the outer peripheral side. The cover members 25 and 26 prevent grease (not shown) enclosed in the guide grooves 22A and 23A from scattering and leaking from between the ball guides 22 and 23, and the balls 24 and the guide grooves 22A and 23A. Keeps good lubrication during.

  Reference numeral 27 denotes a shim as a spacer provided between the anti-rotation mechanism 21 and the casing 1. The shim 27 is formed in a substantially rectangular thin plate shape, and is disposed on the bottom surface of the casing-side accommodation hole 20. It is sandwiched between the guide 22 and the bottom surface of the casing side accommodation hole 20. The shim 27 narrows the distance in the thrust direction between the fixed scroll 3 and the orbiting scroll 12 and adjusts the thrust gap between the fixed scroll 3 and the orbiting scroll 12 to an appropriate value.

  The scroll type air compressor according to the present embodiment has the above-described configuration. When the drive shaft 7 is rotationally driven by the electric motor 2, the rotation of the drive shaft 7 is performed from the eccentric bush 9 via the swivel bearing 14. This is transmitted to the orbiting scroll 12. Thereby, the orbiting scroll 12 revolves around the drive shaft 7 in a state where the rotation prevention mechanism 21 prevents the rotation. At this time, the compression chamber 16 defined between the wrap portion 3B of the fixed scroll 3 and the wrap portion 12B of the orbiting scroll 12 is continuously reduced. As a result, the scroll type air compressor sequentially compresses the outside air sucked from the suction port 17 in each compression chamber 16, and discharges this compressed air from the discharge port 18 toward an external air tank (not shown) or the like. .

  Next, the orbiting radius Sr when the orbiting scroll 12 actually orbits will be described with reference to FIGS.

  First, the orbiting scroll 12 orbits according to the eccentric amount R of the eccentric bush 9. For this reason, the scroll type air compressor according to the present embodiment has a turning radius S 0 determined by the eccentric bush 9. However, by providing a large clearance between the main bearing 8 and the slewing bearing 14, a clearance between the main bearing 8 and the boss portion 1B, and a clearance between the slewing bearing 14 and the boss portion 12C, a large play amount Δ is provided in the eccentric amount R. ing. For this reason, the turning radius S0 by the eccentric bush 9 is a value obtained by adding the eccentric amount R and the play amount Δ (S0 = R + Δ), but the play amount Δ is uncertain, so the actual turning radius of the turning scroll 12 Sr is not determined at the turning radius S0 by the eccentric bush 9.

  Second, the orbiting scroll 12 is restricted in its orbiting motion by the rotation prevention mechanism 21. For this reason, the scroll type air compressor according to the present embodiment has a turning radius S 1 determined by the ball guides 22 and 23 and the balls 24. Specifically, the fixed ball guide 22 and the movable ball guide 23 are provided with guide grooves 22A and 23A for determining the trajectory of the ball 24, respectively. Each of the guide grooves 22A and 23A has a track radius E of the ball 24. For this reason, the turning radius S1 determined by each of the ball guides 22, 23 and the ball 24 is a value twice the orbital radius E as shown in the following equation (1).

  However, the curvature of the guide grooves 22 </ b> A and 23 </ b> A is set to a value slightly larger than the curvature of the outer surface of the ball 24. For this reason, when a lateral load is applied in the radial direction (radial direction) of each of the scrolls 3 and 12, the axial load (thrust load) is overcome and the movable ball guide 23 moves in the radial direction together with the orbiting scroll 12. Displace. Therefore, the orbiting scroll 12 can move with a turning radius slightly smaller than the turning radius S 1 determined by the ball guides 22 and 23 and the ball 24. Accordingly, the actual turning radius Sr of the orbiting scroll 12 is not determined by the turning radius S1 by the rotation prevention mechanism 21, but is determined by the relationship with the turning radius S2 by the wrap portions 3B and 12B described later.

  In the present embodiment, the track radius E of the guide groove 22A and the track radius E of the guide groove 23A are set to the same value, but the track radius of the guide groove 22A and the track radius of the guide groove 23A are slightly different. Different values may be set.

  Third, the orbiting scroll 12 is restricted in its orbiting movement by contacting the wrap portion 3B of the fixed scroll 3 and the wrap portion 12B of the orbiting scroll 12. For this reason, the scroll type air compressor by this Embodiment is provided with turning radius S2 decided by each lap | wrap parts 3B and 12B.

  At this time, in this embodiment, the turning radius S2 by the wrap portions 3B and 12B is set to a value smaller than the turning radius S1 by the rotation prevention mechanism 21 as shown in the following equation (2).

  As a result, the orbiting scroll 12 tries to orbit with the orbiting radius S1 by the rotation prevention mechanism 21, but the displacement larger than the orbiting radius S2 is restricted when the side surfaces of the wrap portions 3B and 12B contact each other. At this time, the orbiting scroll 12 can be slightly displaced by a lateral load in the radial direction. For this reason, the orbiting scroll 12 orbits with the orbiting radius S2 smaller than the orbiting radius S1 by the rotation prevention mechanism 21 due to the lateral load caused by the contact between the wrap portions 3B and 12B. As a result, the orbiting scroll 12 performs the orbiting motion while the side surfaces of the wrap portions 3B and 12B are in contact with each other, so the actual orbiting radius Sr coincides with the orbiting radius S2 by the wrap portions 3B and 12B.

  Here, if the difference between the turning radii S1 and S2 is a small value, the lateral load due to the contact of the wrap portions 3B and 12B is also reduced. Further, the centrifugal force of the orbiting scroll 12 is small in a small scroll type air compressor. For this reason, the contact force between the wrap portions 3B and 12B is also reduced. Moreover, the hard process layers 6 and 15 are provided in the side surface of the lap | wrap parts 3B and 12B. Therefore, the treatment layers 6 and 15 of the wrap portions 3B and 12B are hardly worn or only gradually worn, and the durability is not impaired.

  In particular, as a preferred embodiment, when the total value of the thickness dimension δ1 of the treatment layer 6 and the thickness dimension δ2 of the treatment layer 15 is δ, the turning radius S1 by the anti-rotation mechanism 21 is expressed by the following equation (3). As shown in FIG. 5, the total thickness δ of the processing layers 6 and 15 and the turning radius S2 by the wrap portions 3B and 12B are set to a value smaller than the sum (S2 + δ).

  With this setting, before the processing layers 6 and 15 are all worn, the actual turning radius Sr gradually increases from the turning radius S2 by the wrap portions 3B and 12B, and the turning radius by the rotation prevention mechanism 21 is increased. It becomes equal to S1. When the actual turning radius Sr is larger than the turning radius S1, in addition to the contact force of the wrap portions 3B and 12B, a regulation force that is intended to maintain the turning radius S1 by the rotation prevention mechanism 21 also acts.

  That is, since the orbiting scroll 12 is pressed toward the casing 1 by the internal pressure of the compression chamber 16, the force for narrowing the distance between the ball guides 22 and 23 (the force for pinching the ball 24) is stronger than the centrifugal force. For this reason, since the ball 24 rolls along the deepest part of the guide grooves 22A and 23A of the ball guides 22 and 23, the rotation prevention mechanism 21 generates a regulating force that maintains the turning radius S1.

  For this reason, even if a centrifugal force acts on the orbiting scroll 12, the contact force of the wrap portions 3B and 12B and the regulating force by the rotation prevention mechanism 21 push back the centrifugal force. Therefore, even when the processing layers 6 and 15 are worn and the actual turning radius Sr gradually increases, the actual turning radius Sr becomes stable when the turning radius S1 becomes equal to the turning radius S1 by the rotation prevention mechanism 21, and thereafter. The treatment layers 6 and 15 are hardly worn.

  Thus, in this embodiment, the turning radius S1 determined by the ball guides 22 and 23 and the ball 24 is larger than the turning radius S2 determined by the wrap portions 3B and 12B of the scrolls 3 and 12 (S1> S2). When the scroll 12 makes a turning motion along the turning radius S1, the side surfaces of the wrap portions 3B and 12B of the scrolls 3 and 12 come into contact with each other. Accordingly, the orbiting scroll 12 orbits while the wrap portions 3B and 12B are in contact with each other, and therefore orbits along the orbiting radius S2 smaller than the orbiting radius S1.

  At this time, even if the turning radius is slightly deviated in the vicinity of the turning radius S1, the amount of movement of the turning scroll 12 in the axial direction (thrust direction) toward the fixed scroll 3 is small. Therefore, the tip seals 4 and 13 and the opposite end plate 12A , 3A hardly changes, and the force acting in the radial direction (radial direction) of the orbiting scroll 12 is weak. For this reason, even if the orbiting scroll 12 orbits while the lap portions 3B and 12B of the scrolls 3 and 12 are in contact with each other, no great mechanical loss occurs.

  On the other hand, since the orbiting scroll 12 orbits while the wrap portions 3B and 12B are in contact with each other, the gap between the wrap portions 3B and 12B of the scrolls 3 and 12 can be made as small as possible. For this reason, it can prevent that the compressed air in the compression chamber 16 leaks from the clearance gap between the lap | wrap parts 3B and 12B, and can improve the discharge flow rate and compression efficiency of compressed air.

  Further, since the processing layers 6 and 15 by surface treatment are provided on the side surfaces of the fixed scroll 3 and the orbiting scroll 12 wrap portions 3B and 12B, for example, by providing the hard processing layers 6 and 15 by anodizing treatment, each scroll 3 , 12 even when the side surfaces of the lap portions 3B, 12B are in contact with each other, wear can be suppressed and durability can be improved.

  In particular, in a preferred embodiment, the turning radius S1 determined by the rotation prevention mechanism 21 is set to the turning radius S2 determined by the wrap portions 3B and 12B of the scrolls 3 and 12, and the total value δ of the thickness dimensions δ1 and δ2 of the treatment layers 6 and 15. Is smaller (S2 + δ> S1) than the value obtained by adding (S2 + δ). For this reason, even when the wrap portion 3B of the fixed scroll 3 and the wrap portion 12B of the orbiting scroll 12 come into contact with each other and wear occurs, the wear range is kept within the treatment layers 6 and 15 of the wrap portions 3B and 12B. Thus, wear beyond the treatment layers 6 and 15 can be suppressed, and reliability can be improved.

  Further, since the eccentric amount R of the eccentric bush 9 has a play amount Δ larger than the total value δ of the thickness dimensions δ1 and δ2 of the processing layers 6 and 15, the eccentric bush 9 has the eccentric amount R and the play amount Δ. The orbiting scroll 12 can be orbited at an orbital radius S0 (S0 = R + Δ). However, since the play Δ is uncertain, the actual turning radius Sr of the orbiting scroll 12 is not determined by the orbiting radius S0 by the eccentric bush 9, but the orbiting radius S1 by the rotation prevention mechanism 21 and the orbiting by the wrap portions 3 and 12. It depends on the radius S2. Therefore, by making the turning radius S1 larger than the turning radius S2 (S1> S2), the orbiting scroll 12 can be orbited in a state where the wrap portions 3 and 12 are in contact with each other.

  In the above-described embodiment, three rotation prevention mechanisms 21 are provided on the back surface of the end plate 12A of the orbiting scroll 12. However, four or more rotation prevention mechanisms may be provided.

  In the embodiment, the rotation prevention mechanism 21 is provided between the casing 1 and the orbiting scroll 12. However, the present invention is not limited to this. For example, the casing 1 and the fixed scroll 3 are integrally formed, and the casing side The rotation prevention mechanism 12 may be provided between the fixed scroll 3 and the orbiting scroll 12. In this case, for example, if a back pressure chamber is provided on the back side of the orbiting scroll 12 so that the internal pressure of the compression chamber 16 acts on the back surface of the orbiting scroll 12, a force is applied in the direction in which the orbiting scroll 12 approaches the fixed scroll 3. Good.

  Moreover, in the said embodiment, although it was set as the structure which attaches the chip seals 4 and 13 to the tooth tip of the lap | wrap parts 3B and 12B, it is good also as a structure which abbreviate | omits both or one of the wrap parts 3B and 12B.

  Moreover, in the said embodiment, although it was set as the structure which provides the processing layers 6 and 15 in both the lap | wrap parts 3B and 12B, it is good also as a structure which provides a processing layer only in any one of the wrap parts 3B and 12B.

  Moreover, in the said embodiment, the hard processing layers 6 and 15 shall be formed in each scroll 3 and 12 by performing an anodizing process as a surface treatment. However, the present invention is not limited to this, and each scroll may have a structure in which a soft treatment layer is provided by performing a treatment such as applying a resin as a surface treatment.

  Furthermore, in the above-described embodiment, the scroll type air compressor has been described as an example of the scroll type fluid machine. However, the present invention is not limited to this and can be widely applied to, for example, a vacuum pump, a refrigerant compressor, and the like. is there.

It is a longitudinal section showing a scroll type air compressor by an embodiment of the invention. FIG. 2 is an enlarged vertical sectional view showing a fixed scroll and a turning scroll in FIG. 1 in an enlarged manner. FIG. 2 is an enlarged longitudinal sectional view showing an enlargement of the periphery of a rotation prevention mechanism in FIG. 1. It is the cross-sectional view which looked at the lap | wrap part of the fixed scroll and the turning scroll from the arrow IV-IV direction in FIG. FIG. 5 is an enlarged cross-sectional view in which a part in FIG. 4 is enlarged.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 3 Fixed scroll 3A, 12A End plate 3B, 12B Lapping part 6,15 Processing layer 7 Drive shaft 9 Eccentric bush (crank mechanism)
12 orbiting scroll 14 orbiting bearing 21 rotation prevention mechanism 22 fixed ball guide 22A, 23A guide groove 23 movable ball guide 24 ball S0, S1, S2 orbiting radius

Claims (4)

A casing, a fixed scroll provided with a spiral wrap portion provided on the casing, a drive shaft rotatably provided on the casing, and a wrap portion of the fixed scroll provided rotatably on the drive shaft. A orbiting scroll having a spiral wrap portion defining a plurality of compression chambers therebetween, and a rotation prevention mechanism provided between the casing side and the orbiting scroll to prevent the orbiting scroll from rotating,
The rotation prevention mechanism includes a fixed ball guide fixed to the casing side and having an annular guide groove, a movable ball guide fixed to the orbiting scroll and having an annular guide groove at a position facing the fixed ball guide, In a scroll fluid machine comprising a ball sandwiched between a guide groove of a fixed ball guide and a guide groove of a movable ball guide,
When the turning radius obtained by the fixed ball guide, the movable ball guide and the ball is S1, and the turning radius determined by the side surface of the lap portion of the fixed scroll and the turning scroll is S2, S1> S2. A scroll type fluid machine.   The scroll type fluid machine according to claim 1, wherein a processing layer by surface treatment is provided on a side surface of at least one of the orbiting scroll and the fixed scroll.   The relationship between the turning radii S1 and S2 is S2 + δ> S1> S2, where δ is a total value of the thickness dimension of the processing layer of the fixed scroll and the thickness dimension of the processing layer of the orbiting scroll. The scroll fluid machine according to 2. A crank mechanism having an eccentric amount is provided between the orbiting scroll and the drive shaft,
The scroll fluid machine according to claim 3, wherein the eccentric amount of the crank mechanism has a play larger than a total value δ of the thicknesses of the processing layers.

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