JP5681019B2 - Scroll type fluid machine - Google Patents

Description

  The present invention relates to a scroll fluid machine that is preferably used to compress a fluid such as air.

  Generally, a two-stage scroll fluid machine that compresses air in two stages, a low-pressure side and a high-pressure side, is provided with a cylindrical casing extending in the axial direction and fixed on both ends of the casing, and spirals on the surface. A fixed scroll on the low-pressure side and the high-pressure side on which a lap portion is erected, and an output shaft disposed between the fixed scroll on the low-pressure side and the high-pressure side and disposed in the casing and arranged equal to the axis of the casing And a plurality of compressions that are provided on both ends of the output shaft of the motor so as to oppose the low-pressure side and high-pressure side fixed scrolls and overlap the wrap portions of the low-pressure side and high-pressure side fixed scrolls on the surface. The lap portion that defines the chamber is roughly constituted by a low pressure side and a high pressure side orbiting scroll. Also, between the low-pressure side compression chamber and the high-pressure side compression chamber, piping that communicates between the compression chambers in order to suck the compressed air discharged from the low-pressure side compression chamber into the high-pressure side compression chamber. Etc. are provided.

  Here, between the low-pressure side orbiting scroll and the casing, there is provided a rotation preventing mechanism for preventing the rotation of the orbiting scroll and receiving a thrust load acting on the orbiting scroll.

  On the other hand, a back pressure chamber is defined between the casing and the fixed scroll on the high pressure side, located on the back side of the orbiting scroll on the high pressure side, and the compression discharged from the compression chamber on the low pressure side to the back pressure chamber. By causing air to flow in as an intermediate pressure, the thrust load is reduced by balancing the pressure of the orbiting scroll on the high pressure side. At this time, the central portion of the high-pressure side orbiting scroll can be positioned in the thrust direction by the output shaft of the electric motor (see, for example, Patent Document 1).

JP 2004-116471 A

  In the scroll fluid machine of Patent Document 1, there is no mechanism for receiving the thrust load acting on the outer peripheral side of the high-pressure side orbiting scroll. There is a problem that efficiency decreases.

  Therefore, in order to suppress the deformation of the orbiting scroll, it is conceivable to increase the thickness of the end plate to increase the rigidity. However, in this case, the orbiting scroll becomes larger and its mass increases. This hinders the downsizing and weight reduction of machines.

  An object of the present invention is to provide a scroll type fluid machine which can be reduced in size and weight by preventing deformation in the thrust direction without increasing the size of the orbiting scroll on the high pressure side.

  In order to solve the above-described problems, the configuration of the present invention is characterized in that an eccentric bush weight on the low pressure side that adjusts the rotational balance of the orbiting scroll and the rotation of the orbiting scroll between the low pressure side orbiting scroll and the casing. A low-pressure side rotation prevention mechanism is provided to prevent the rotation of the orbiting scroll between the high-pressure side scroll and the casing. The rotation prevention mechanism is provided.

  According to the present invention, the rotational balance of the orbiting scroll on the low pressure side and the high pressure side can be adjusted by the dedicated eccentric bush weight. The thrust load acting on each orbiting scroll can be received by a dedicated rotation prevention mechanism. In particular, even in a high-pressure side orbiting scroll in which a large thrust load is applied by high-pressure compressed air, it is possible to prevent deformation of the end plate or the like by a high-pressure side rotation prevention mechanism without changing the structure to increase rigidity. it can. Thereby, it is possible to prevent the high-pressure side orbiting scroll from becoming large, and the entire scroll fluid machine can be reduced in size and weight.

It is a longitudinal section showing a two-stage scroll type air compressor by an embodiment of the invention. It is sectional drawing of the principal part expansion which shows the sealing member etc. in FIG. It is a longitudinal cross-sectional view which shows the state which comprised the one-stage type scroll type air compressor using the low pressure side scroll. It is a longitudinal cross-sectional view which shows the state which comprised the scroll type air compressor of the 1 step | paragraph type | mold using the high pressure side scroll. It is a longitudinal cross-sectional view which shows the 1 step | paragraph type scroll type air compressor using the scroll of the low voltage | pressure side by the modification of this invention.

  Hereinafter, a case where the scroll type fluid machine according to the embodiment of the present invention is applied to a two-stage scroll type air compressor having a low pressure side compression unit and a high pressure side compression unit will be described as an example. This will be described in detail with reference to FIG.

  In FIG. 1, reference numeral 1 denotes a two-stage scroll type air compressor according to this embodiment. The scroll type air compressor 1 includes a casing 2 described later, fixed scrolls 9A and 9B, an electric motor 14, a rotating shaft 17, eccentric bush weights 21A and 21B, orbiting scrolls 28A and 28B, rotation prevention mechanisms 35A and 35B, and a seal member. 40 or the like.

  Since the scroll type air compressor 1 has substantially the same components on the low pressure side as the first stage and the high pressure side as the second stage, in the following description, the components on the low pressure stage side will be described. The reference numeral “A” is attached to the reference numeral, and the constituent elements on the high-pressure stage side are attached with the reference numeral “B”. In order to avoid duplication of description between the low-pressure stage and the high-pressure stage, the components on the low-pressure stage side will be mainly described. The components on the high-pressure disconnection side will be described only about the components with features. Description of these components will be omitted.

  Reference numeral 2 denotes a cylindrical casing that forms an outer frame of the scroll type air compressor 1. The casing 2 is formed as a stepped cylindrical body having an axis O1-O1 extending in the left and right directions in FIG. Bearing attachment bodies 3A and 3B are provided on the right and left ends of the casing 2 so as to be symmetrical in the left and right directions.

  The bearing mounting body 3A located on the right side which is the low pressure stage side is formed in a double cylinder shape by a large-diameter cylindrical portion 4A and a small-diameter bearing cylindrical portion 5A. Between each cylinder part 4A and 5A, the coupling accommodation hole 6A is provided in the circumferential direction several places, for example, three places. On the other hand, an air inflow port 7A into which air (atmosphere) flows is formed in the large-diameter cylindrical portion 4A, and the air inflowing from the air inflow port 7A is a gap on the outer peripheral side of the fixed scroll 9A and the orbiting scroll 28A described later. To the outermost compression chamber 34A. Furthermore, the casing 2 side of the bearing tube portion 5A is reduced in diameter to form a rotary shaft insertion hole 8A.

  Here, the inflow port 7B provided in the bearing mounting body 3B located on the left side on the high pressure stage side allows compressed air discharged from the compression chamber 34A on the low pressure side to the back pressure chamber 39 via the communication pipe 43 described later. It is a compressed air inlet as a compressed fluid inlet for inflow.

  9A is a low-pressure stage fixed scroll provided on the bearing mounting body 3A side of the casing 2, and the fixed scroll 9A has a substantially disc-like shape with its center aligned with the axis O1-O1 of the casing 2. The mirror plate 10A, a spiral wrap portion 11A standing on the surface of the mirror plate 10A, and a cylindrical portion 12A protruding in the axial direction so as to surround the wrap portion 11A from the outer peripheral side of the mirror plate 10A are roughly configured. ing. The end plate 10A of the fixed scroll 9A is provided with a compressed air outlet 13A located on the center side (on the axis O1-O1). The fixed scroll 9A is attached to the large diameter cylindrical portion 4A of the bearing mounting body 3A via a bolt or the like on the opening side of the cylindrical portion 12A.

  Here, the wrap portion 11B of the fixed scroll 9B at the high pressure stage is formed in the same spiral shape as the lap portion 11A on the low pressure side because the orbiting scrolls 28A and 28B of the low pressure stage and the high pressure stage are swung with the same turning radius. In order to increase the pressure, only the height dimension is made small.

  Reference numeral 14 denotes an electric motor as an electric motor provided in the casing 2. The electric motor 14 includes a stator 15 made of a permanent magnet or the like fixed to the inner peripheral side of the casing 2, and a cylindrical rotor 16 that is rotatably arranged on the inner peripheral side of the stator 15. ing. In the electric motor 14, the axes of the stator 15 and the rotor 16 are arranged on the same axis as the axis O 1 -O 1 of the casing 2, and a rotation shaft 17 described later is driven to rotate about the axis O 1 -O 1.

  Reference numeral 17 denotes a rotation shaft as an output shaft that is rotationally driven by the electric motor 14. The rotary shaft 17 is rotatably supported via main bearings 18A and 18B in the bearing tube portions 5A and 5B of the bearing mounting bodies 3A and 3B. The rotating shaft 17 is fitted into the rotor 16 of the electric motor 14 using a means such as press fitting, and rotates about the axis O1-O1.

  The rotary shaft 17 has female screw holes 19A and 19B formed at the shaft end on the low pressure stage side and the shaft end on the high pressure stage side, which are symmetrical in the left and right directions, respectively. The female screw holes 19A and 19B are for screwing bolts 27A and 27B for attaching eccentric bush weights 21A and 21B described later. The female screw holes 19A and 19B are decentered by the same distance in the same direction with respect to the axis O1-O1 of the rotating shaft 17, for example, the axis O2- which is eccentric by the dimension δ with respect to the axis O1-O1 of the rotating shaft 17. It is arranged at the position of O2. As a result, the eccentric bush weights 21A and 21B attached to the female screw holes 19A and 19B using the bolts 27A and 27B can be attached in a stopped state by the bolts 27A and 27B shifted from the center, and are attached to the rotary shaft 17. Can be installed at the same position in the circumferential direction.

  Further, an annular concave groove 20 that constitutes a part of a seal member 40 described later is provided on the left side of the rotary shaft 17 on the high pressure side. The concave groove 20 is disposed at a position facing the inner surface of the rotary shaft insertion hole 8B of the bearing mounting body 3B on the high pressure side. An elastic ring 41 and a band member 42, which will be described later, are accommodated in the concave groove 20 in order to hermetically seal between the rotary shaft insertion hole 8B.

  An eccentric bushing weight 21A is provided at the right end of the rotary shaft 17. The eccentric bushing weight 21A is an orbiting scroll which will be described later on an axis O2-O2 which is eccentric by a dimension δ with respect to the axis O1-O1 of the casing 2 or the like. 28A is arranged. The eccentric bush weight 21 </ b> A is configured by an eccentric portion that is disposed at a position where the orbiting scroll 28 </ b> A is eccentric with respect to the rotating shaft 17, and a weight portion that is provided on the outer peripheral side of the eccentric portion.

  An eccentric portion of the eccentric bush weight 21A includes a main shaft hole 22A arranged on the electric motor 14 side with the axis O1-O1 as a center and into which the rotary shaft 17 is inserted, and an axis O2-O2 eccentric from the main shaft hole 22A by a dimension δ. And a revolving shaft hole 23A into which a later-described washer 26A is inserted, and a bearing housing cylinder 24A projects from the revolving shaft hole 23A. On the other hand, the eccentric bush weight 21A is provided with a weight portion 25A located on the opposite side to the eccentric direction of the turning shaft hole 23A with respect to the main shaft hole 22A. The weight portion 25A is formed as an arc-shaped weight extending to the electric motor 14 side opposite to the orbiting scroll 28A.

  In the eccentric bush weight 21A, after inserting the right end portion of the rotary shaft 17 into the main shaft hole 22A, the washer 26A is fitted into the turning shaft hole 23A, and the bolt 27A inserted through the washer 26A is screwed into the female screw hole 19A of the rotary shaft 17. To wear. Thereby, the eccentric bush weight 21 </ b> A can be attached to the rotating shaft 17.

  The low-pressure stage (low-pressure side) eccentric bush weight 21A and the high-pressure stage (high-pressure side) eccentric bush weight 21B are arranged symmetrically in the left and right directions. For example, by using the same member, G2 is at the same position, and the weights 25A and 25B have the same mass. Moreover, the eccentric bush weights 21 </ b> A and 21 </ b> B of the low pressure stage and the high pressure stage are attached to the rotation shaft 17 at the same position (also referred to as the same phase) in the circumferential direction.

  Reference numeral 28A denotes a low-pressure stage orbiting scroll which is provided in the casing 2 so as to face the fixed scroll 9A. The low-pressure stage orbiting scroll 28A is roughly constituted by a mirror plate 29A formed in a substantially disc shape and a spiral wrap portion 30A standing on the surface of the mirror plate 29A. Further, the orbiting scroll 28B of the high-pressure stage is also protruded from the end plate 29B formed in a substantially disc shape, a spiral wrap portion 30B, and the back surface (surface opposite to the wrap portion 30A) of the end plate 29A. The cylindrical boss portion 31A is generally configured. The boss portion 31A is mounted in the bearing housing cylinder 24A of the eccentric bush weight 21A via a swing bearing 32A.

  Further, on the outer diameter side of the rear surface of the orbiting scroll 28A, there are a plurality of mounting recesses 33A to which a second thrust receiver 37A of a rotation prevention mechanism 35A described later is fitted and attached, for example, at a plurality of circumferential positions, for example, three locations (FIG. 1). Only one of them is shown), and these mounting recesses 33A are arranged at positions corresponding to the coupling accommodation holes 6A of the bearing mounting body 3A.

  On the other hand, the center of the boss 31A of the orbiting scroll 28A is disposed on the axis O2-O2 that is eccentric in the radial direction by a dimension δ with respect to the center (axis O1-O1) of the fixed scroll 9A. In this state, the wrap portion 30A of the orbiting scroll 28A is disposed so as to overlap the wrap portion 11A of the fixed scroll 9A, and a plurality of compression chambers 34A are formed between the wrap portions 22A and 30A. .

  The orbiting scroll 28A is driven by the electric motor 14 described later via the rotating shaft 17 and the eccentric bush weight 21A, and performs the orbiting operation on the fixed scroll 9A in a state where the rotation is restricted by the rotation preventing mechanism 35A. Thereby, the compression chamber 34A defined on the outer diameter side sucks air from the air inlet 7A and continuously compresses the air in each compression chamber 34A. And the air compressed to predetermined pressure is discharged to the below-mentioned communication piping 43 from the compression chamber 34A of the center side through the outflow port 13A of the fixed scroll 9A.

  Here, since the orbiting scroll 28A at the low pressure stage and the orbiting scroll 28B at the high pressure stage are operated by the eccentric bush weights 21A and 21B having the same shape, the orbiting radii are equal. Moreover, the orbiting scrolls 28A and 28B are formed so that their masses are equal and the gravity center positions G3 and G4 are substantially the same position.

  Specifically, since the wrap portion 30B provided in the high-pressure stage orbiting scroll 28B is formed in the same spiral shape as the wrap section 30A of the low-pressure stage orbiting scroll 28A, the air compressed to the intermediate pressure is further compressed. Therefore, the height dimension is low. Along with this, the mass of the wrap portion 30B is reduced, so by increasing the thickness of the end plate 29B to increase the mass, the high-pressure stage orbiting scroll 28B and the low-pressure stage orbiting scroll 28A have the same mass. Yes.

  Reference numeral 35A denotes a plurality of, for example, three rotation prevention mechanisms (only one is shown) provided between the bearing mounting body 3A of the casing 2 and the rear surface of the end plate 29A of the orbiting scroll 28A. These rotation prevention mechanisms 35A are constituted by a ball coupling mechanism. The anti-rotation mechanism 35A prevents the orbiting scroll 28A from rotating and receives a thrust load, and is disposed between the coupling receiving hole 6A of the bearing mounting body 3A and the mounting recess 33A of the orbiting scroll 28A. Has been.

  That is, the anti-rotation mechanism 35A composed of a ball coupling mechanism includes a first thrust receiver 36A inserted into the bottom of the coupling receiving hole 6A of the bearing mounting body 3A, and the first thrust receiver 36A in the axial direction. A second thrust receiver 37A that is inserted into the mounting recess 33A of the orbiting scroll 28A, and a sphere 38A composed of a steel ball or the like that can be rolled between the first and second thrust receivers 36A and 37A. It is comprised including.

  As a result, the rotation prevention mechanism 35A causes the casing 2 side to receive the thrust load acting on the end plate 29A of the orbiting scroll 28A due to the pressure in each compression chamber 34A via the thrust receivers 36A and 37A and the sphere 38A. Can do. The rotation prevention mechanism 35A prevents the orbiting scroll 28A from rotating by rolling the sphere 38A along a circular track (not shown) formed in the thrust receivers 36A and 37A. The low-pressure stage rotation prevention mechanism 35 </ b> A and the high-pressure stage rotation prevention mechanism 35 </ b> B are the same members arranged symmetrically on the left and right.

  Reference numeral 39 denotes a back pressure chamber which is located between the bearing mounting body 3B and the fixed scroll 9B on the high pressure stage side and is defined on the back side of the orbiting scroll 28B. The back pressure chamber 39 allows the compressed air of intermediate pressure discharged from the compression chamber 34A of the low pressure stage to flow through the compressed air inlet 7B, thereby pressing the orbiting scroll 28B with the compressed air and receiving the thrust load. To do.

  Reference numeral 40 denotes a seal member provided between the bearing mounting body 3 </ b> B on the high-pressure stage side and the rotary shaft 17, that is, in the concave groove 20 of the rotary shaft 17. The seal member 40 is airtight so that air in the back pressure chamber 39 does not leak into the electric motor 14. As shown in FIG. 2, the seal member 40 includes the concave groove 20 provided in the rotary shaft 17 so as to correspond to the rotary shaft insertion hole 8 </ b> B of the bearing mounting body 3 </ b> B, and an elastic ring accommodated in the concave groove 20. 41 and an annular band member 42 provided on the outer peripheral side of the elastic ring 41.

  Here, the elastic ring 41 presses the band member 42 against the inner surface of the rotary shaft insertion hole 8B, and a general rubber ring called an O-ring can be used. On the other hand, the band member 42 is formed, for example, by rolling a belt-like body made of a resin material having self-lubricating properties into an annular shape, and slidably comes into surface contact with the inner surface of the rotary shaft insertion hole 8B.

  Reference numeral 43 denotes a communication pipe as a communication path for communicating the low pressure stage compression chamber 34A and the high pressure stage compression chamber 34B. The communication pipe 43 is configured by a metal pipe or the like provided outside the casing 2 and provided between the low pressure stage fixed scroll 9A and the high pressure stage side bearing mounting body 3B. The communication pipe 43 has an upstream end connected to the outlet 13A of the fixed scroll 9A and a downstream end connected to the compressed air inlet 7B of the bearing mounting body 3B.

  In the middle of the communication pipe 43, an intercooler 44 is provided for cooling the compressed air having an intermediate pressure that has been heated by compression heat or the like. The intercooler 44 can reduce the volume of the compressed air thermally expanded by the compression heat, and can increase the compression efficiency of the subsequent compression chamber 34B.

  Next, how to adjust the rotation balance when the two-stage scroll type air compressor 1 is operated will be described.

  The position of the center of gravity of the scroll type air compressor 1 is located at a position G0 on the axis O1-O1 which is the center of the whole. The distance dimension from the gravity center position G0 to the gravity center positions G1 and G2 of the eccentric bush weights 21A and 21B is the same dimension L1. Further, the distance dimension from the gravity center position G0 to the gravity center positions G3 and G4 of the orbiting scrolls 28A and 28B is the same dimension L2.

  Here, when the orbiting scroll 28A and the eccentric bush weight 21A in the low pressure stage are rotationally driven, the eccentric mass M of the orbiting scroll 28A generates a moment F1 that is directed radially outward by the centrifugal force due to the orbiting radius R. The magnitude of this moment F1 can be expressed by MR × L2. On the other hand, the eccentric mass m of the eccentric bush weight 21A generates a moment F2 in a direction opposite to the moment F1 of the orbiting scroll 28A due to the centrifugal force due to the orbiting radius r, and this moment F2 can be expressed as mr × L1.

  Therefore, in the present embodiment, the moment F1 of the orbiting scroll 28A and the moment F2 of the eccentric bush weight 21A are made equal (F1 = F2), and the balance on the low pressure stage side is adjusted.

  Similarly, even on the high pressure stage side, the balance on the high pressure stage side can be adjusted by making the moment F1 of the orbiting scroll 28B equal to the moment F2 of the eccentric bush weight 21B.

  In general, the two-stage scroll type air compressor 1 can adjust the rotational balance by three eccentric masses. On the other hand, in the present embodiment, two eccentric masses are provided on each of the low pressure side and the high pressure side, and a total of four are provided. As will be described later, this configuration is easy by simply adding one eccentric mass when forming either one-stage scroll air compressors 51 and 61 by omitting either the low-pressure stage or the high-pressure stage. The rotation balance can be adjusted.

  Next, the case where the one-stage scroll type air compressor 51 is manufactured using the components of the two-stage type scroll air compressor 1 will be described (see FIG. 3). The one-stage scroll air compressor 51 includes only the low-pressure scrolls 9A and 28A by omitting the high-pressure scrolls 9B and 28B.

  In the scroll type air compressor 51, the low pressure stage fixed scroll 9A is attached to the bearing attachment body 3B on the high pressure stage side, and the orbiting scroll 28A is attached to the eccentric bush weight 21B so as to face the fixed scroll 9A. On the other hand, on the low pressure stage side, a stepped cylindrical lid body 52 is attached instead of the removed bearing attachment body 3 </ b> A, and the rotating shaft 17 is supported by the bearing 53. Furthermore, by attaching a balance weight 54 to the right end portion of the rotating shaft 17, a one-stage scroll type air compressor 51 can be manufactured. Since the back pressure chamber 39 is at atmospheric pressure, the seal member 40 of the rotating shaft 17 is omitted.

  Here, how to adjust the rotation balance when the one-stage scroll type air compressor 51 is operated will be described.

  The position of the center of gravity of the scroll type air compressor 51 is a position G5 on the axis O1-O1 serving as the center of the whole. A distance dimension from the center of gravity position G5 to the center of gravity position G2 of the eccentric bush weight 21B is a dimension L3. The distance dimension from the gravity center position G5 to the gravity center position G3 of the orbiting scroll 28A is the dimension L4. Further, the distance dimension from the gravity center position G5 to the gravity center position G6 of the balance weight 54 is a dimension L5.

  Here, when the orbiting scroll 28A and the eccentric bush weight 21B are rotationally driven, the eccentric mass M of the orbiting scroll 28A generates a moment F3 that is directed radially outward by the centrifugal force due to the orbiting radius R. The magnitude of this moment F3 can be expressed as MR × L4. On the other hand, the eccentric mass m of the eccentric bush weight 21B generates a moment F4 in a direction opposite to the moment F1 of the orbiting scroll 28A due to the centrifugal force due to the orbiting radius r, and this moment F4 can be expressed as mr × L3.

  Further, the eccentric mass M ′ of the balance weight 54 generates a moment F5 in the same direction as the moment F3 of the orbiting scroll 28A (the direction opposite to the moment F4 of the eccentric bush weight 21B) due to the centrifugal force caused by the orbiting radius R ′. The moment F5 can be expressed by M′R ′ × L5. Here, since the gravity center position G6 of the balance weight 54 is far away from the gravity center position G5, the eccentric mass M 'can be set small, and the lid body 52 can be formed compactly.

  In the one-stage scroll type air compressor 51, the moment F3 of the orbiting scroll 28A, the moment F4 of the eccentric bush weight 21A, and the moment F5 of the balance weight 54 are set to the following relationship.

  Thereby, the one-stage scroll type air compressor 51 can be manufactured by using the constituent members of the two-stage type scroll air compressor 1. In addition, the balance weight 54 can adjust the rotational balance during operation.

  Next, a case where the one-stage scroll type air compressor 61 having only the high-pressure stage scrolls 9B and 28B is manufactured by omitting the low-pressure stage scrolls 9A and 28A will be described (see FIG. 4).

  The scroll type air compressor 61 attaches the cover body 52 and the bearing 53 described above in place of the removed bearing mounting body 3A. On this, it can be manufactured by attaching a dedicated balance weight 62 to the scroll type air compressor 61 at the right end of the rotary shaft 17. Note that the method of adjusting the rotation balance of the scroll air compressor 61 is substantially the same as that of the scroll air compressor 51, and therefore will be omitted.

  The two-stage scroll type air compressor 1 according to the present embodiment has the above-described configuration. Next, the operation thereof will be described.

  First, when the rotor 16 is rotationally driven by energizing the stator 15 side of the electric motor 14, the rotating shaft 17 rotates about the axis O1-O1. The eccentric bush weights 21A and 21B rotate together with the rotating shaft 17 to cause the orbiting scrolls 28A and 28B to orbit at a turning radius of dimension δ. As a result, on the low pressure stage side, outside air is sucked from the air inlet 7A provided on the outer peripheral side of the bearing mounting body 3A of the casing 2, and this air is compressed between the fixed scroll 9A and the orbiting scroll 28A in the low pressure stage. Compression is performed sequentially in the chamber 34A. The compressed air compressed in each compression chamber 34A is discharged into the communication pipe 43 from the outlet 13A provided at the center of the fixed scroll 9A.

  On the other hand, on the high pressure stage side, compressed air of intermediate pressure supplied from the communication pipe 43 flows into the compressed air inlet 7B of the bearing mounting body 3B, and this compressed air is fixed to the fixed scroll of the high pressure stage via the back pressure chamber 39. Compression is sequentially performed in each compression chamber 34B between 9B and the orbiting scroll 28B. The high-pressure compressed air that is further compressed in each compression chamber 34B is discharged outward from an outlet 13B provided at the center of the fixed scroll 9B, and is stored in, for example, an air tank (not shown). Is done.

  Here, when the orbiting scrolls 28A and 28B are turned by the electric motor 14, the orbiting scrolls 28A and 28B are eccentric from the center of rotation, thereby generating a moment F1 directed radially outward. However, since the eccentric bush weights 21A and 21B are provided so as to correspond to the respective orbiting scrolls 28A and 28B, the orbiting scrolls 28A and 28B are orbited in a balanced manner by the moment F2 in the reverse direction by the eccentric bush weights 21A and 21B. It can be operated.

  Further, during the compression operation, the pressure in the compression chambers 34A and 34B presses the orbiting scrolls 28A and 28B toward the electric motor 14 (thrust load). On the other hand, the anti-rotation mechanisms 35A and 35B composed of ball coupling mechanisms provided on the back surfaces of the respective orbiting scrolls 28A and 28B receive a thrust load acting on the orbiting scrolls 28A and 28B. It is possible to prevent compression leakage by suppressing deformation of the end plates 29A and 29B.

  Thus, according to the present embodiment, in the two-stage scroll type air compressor 1, the low-pressure stage eccentric bush weight 21A and the rotation prevention mechanism 35A are provided between the low-pressure stage orbiting scroll 28A and the casing 2. The high-pressure stage eccentric bush weight 21B and the rotation prevention mechanism 35B are provided between the high-pressure stage orbiting scroll 28B and the casing 2.

  Therefore, the rotational balance of the orbiting scroll 28A in the low pressure stage can be adjusted by the dedicated eccentric bush weight 21A, and the rotation balance of the orbiting scroll 28B in the high pressure stage can be adjusted by the dedicated eccentric bush weight 21B. The thrust load acting on the orbiting scrolls 28A and 28B by the compressed air in the compression chambers 34A and 34B can be received by the rotation prevention mechanisms 35A and 35B. In particular, even in the high-pressure stage orbiting scroll 28B in which a large thrust load is applied by the high-pressure compressed air, the end plate 29B or the like is provided by the rotation prevention mechanism 35B without changing the structure for increasing the rigidity such as increasing the end plate 29B. Can be prevented from being deformed.

  As a result, it is possible to prevent deformation of the end plate 29B and the like in the thrust direction without increasing the size of the high-pressure stage orbiting scroll 28B, so that the entire scroll type air compressor 1 can be reduced in size and weight.

  In addition, since eccentric bush weights 21A and 21B corresponding to the orbiting scrolls 28A and 28B of the low pressure stage and the high pressure stage are provided, for example, one of the scrolls of the low pressure stage and the high pressure stage is removed, and the lid 52 is attached to this portion. The single-stage scroll type air compressors 51 and 61 can be formed simply by attaching the bearing 53, the balance weights 54 and 62, and the like. Thus, by sharing many parts, the one-stage scroll air compressors 51 and 61 can be manufactured easily and inexpensively.

  Further, since the seal member 40 is provided between the rotary shaft 17 and the bearing mounting body 3B, the back pressure chamber 39 can be kept airtight. The seal member 40 is configured such that an elastic band 41 presses an annular band member 42 made of a resin material having self-lubricating properties against the inner surface of the rotary shaft insertion hole 8B. Thereby, while maintaining the pressure of the back pressure chamber 39 stably, the frictional resistance with the bearing attachment body 3B can be reduced, and the compression efficiency can be increased.

  On the other hand, the eccentric bush weights 21 </ b> A and 21 </ b> B of the low pressure stage and the high pressure stage are arranged at the same position in the circumferential direction of the rotating shaft 17. As a result, the low-pressure stage eccentric bushing weight 21A and the high-pressure stage eccentric bushing weight 21B can be attached to the rotary shaft 17 at the same circumferential position with the same mounting structure, thereby preventing misassembly and productivity. The improvement etc. can be aimed at.

  In the scroll type air compressor 1, the casing 2, the rotating shaft 17, the eccentric bush weights 21A and 21B, and the anti-rotation mechanisms 35A and 35B are arranged symmetrically in the low pressure stage and the high pressure stage. Can be assembled. It can also be used as a common part in the low pressure stage and the high pressure stage.

  Further, since the anti-rotation mechanisms 35A and 35B are formed by a ball coupling mechanism, the orbiting scrolls 28A and 28B can be smoothly rotated, and a thrust load can be received via the spheres 38A and 38B. Can do.

  In the embodiment, the one-stage scroll type air compressor 51 is configured by omitting the high-pressure stage scrolls 9B and 28B and replacing the low-pressure stage scrolls 9A and 28A at these positions. However, the present invention is not limited to this, and may be configured as a one-stage scroll type air compressor 71 according to a modification shown in FIG. That is, the scroll type air compressor 71 attaches the lid body 52 and the bearing 53 in place of the bearing attachment body 3B on the high pressure stage side. On this, it can be manufactured by attaching a dedicated balance weight 72 to the scroll type air compressor 71 at the left end of the rotating shaft 17. In this scroll type air compressor 71, the periphery of the brush serving as a heat generation source can be moved away from the scrolls 9A and 9B.

  Further, in the embodiment, as an electric motor, the brush type electric motor 14 of a type in which each component is appropriately assembled is illustrated as an example. However, the present invention is not limited to this, and for example, an assembled brush-type electric motor, a brushless electric motor, or the like may be used as the electric motor.

  Further, in the embodiment, the case where the low-pressure stage and high-pressure stage orbiting scrolls 28A and 28B are formed to have the same orbiting radius and the same mass has been described as an example. However, the present invention is not limited to this, and the turning radius and mass of the orbiting scrolls of the low pressure stage and the high pressure stage may be different. This is possible because a dedicated eccentric bush weight is provided for each orbiting scroll.

  Further, in the embodiment, the scroll type air compressors 1, 51, 61 have been described as examples of the scroll type fluid machine. However, the present invention is not limited to this, and can be widely applied to, for example, vacuum pumps, refrigerant compressors, and the like.

  Next, the invention included in the above embodiment will be described. That is, in the present invention, the seal member includes an annular groove provided on the outer peripheral side of the output shaft of the electric motor, an elastic ring accommodated in the groove, and an annular groove provided on the outer peripheral side of the elastic ring. It is comprised by the band member. Thereby, between a casing and an output shaft can be hold | maintained airtight by a sealing member, and the pressure of a back pressure chamber can be maintained stably. Moreover, since the band member can slidably contact the inner surface of the output shaft insertion hole, the frictional resistance between the casing and the output shaft can be reduced, and the compression efficiency can be increased. it can.

  Further, according to the present invention, the eccentric bush weight on the low pressure side and the eccentric bush weight on the high pressure side are attached to the same position in the circumferential direction with respect to the output shaft of the electric motor. As a result, the eccentric bush weight on the low-pressure side and the eccentric bush weight on the high-pressure side can be attached to the output shaft in the same circumferential position with the same mounting structure, preventing incorrect assembly, improving productivity, etc. Can be achieved.

  According to the present invention, the casing, the output shaft of the electric motor, the eccentric bush weight, and the rotation prevention mechanism are arranged symmetrically on the low pressure side and the high pressure side. As a result, the casing, the output shaft of the motor, the eccentric bush weight, and the rotation prevention mechanism that are arranged symmetrically on the low-pressure side and the high-pressure side can be easily assembled by the same operation. It can also be used as a common part on the low pressure side and the high pressure side.

  According to the present invention, the anti-rotation mechanism is constituted by a ball coupling mechanism having a sphere that rolls on a specified arc. Thereby, the rotation prevention mechanism can smoothly turn the orbiting scroll, and can receive the thrust load via the sphere.

1 Two-stage scroll type air compressor (scroll type fluid machine)
2 Casing 3A, 3B Bearing mounting body 7A Air inlet 7B Compressed air inlet (compressed fluid inlet)
9A, 9B Fixed scroll 10A, 10B, 29A, 29B End plate 11A, 11B, 30A, 30B Lap portion 13A, 13B Outlet 14 Electric motor (electric motor)
17 Rotating shaft (Output shaft)
20 concave groove 21A, 21B eccentric bush weight 25A, 25B weight portion 28A, 28B orbiting scroll 34A, 34B compression chamber 35A, 35B rotation prevention mechanism 38A, 38B sphere 39 back pressure chamber 40 seal member 41 elastic ring 42 band member 43 communication piping (Communication passage)
51, 61 One-stage scroll air compressor O1-O1 casing axis O2-O2 swivel axis

Claims (5)

A cylindrical casing extending in the axial direction;
A fixed scroll on the low-pressure side and the high-pressure side, each of which is fixedly provided at both ends of the casing and has a spiral wrap portion standing on the surface;
An electric motor having an output shaft disposed between the low-pressure side and the fixed scroll on the high-pressure side and disposed in the casing and disposed equal to the axis of the casing;
A plurality of compression chambers are defined on opposite surfaces of the output shaft of the electric motor so as to face the low-pressure side and high-pressure side fixed scrolls and overlap with the lap portions of the low-pressure side and high-pressure side fixed scrolls on the surface. A low-pressure side, a high-pressure side orbiting scroll with a lap section,
A communication passage communicating between the compression chambers in order to suck the compressed air discharged from the compression chamber on the low pressure side into the compression chamber on the high pressure side,
A back pressure chamber is defined between the casing and the fixed scroll on the high pressure side, located on the back side of the orbiting scroll on the high pressure side,
The high pressure side casing is provided with a compressed fluid inlet through which the compressed fluid discharged from the low pressure side compression chamber flows into the back pressure chamber via the communication path,
In a scroll type fluid machine configured to provide a seal member for hermetically holding the back pressure chamber between the high pressure side casing and the output shaft of the electric motor,
Between the low-pressure side orbiting scroll and the casing, a low-pressure side eccentric bush weight for adjusting the rotation balance of the orbiting scroll and a low-pressure side rotation prevention mechanism for preventing the rotation of the orbiting scroll are provided,
Between the high-pressure side orbiting scroll and the casing, a high-pressure side eccentric bush weight for adjusting the rotation balance of the orbiting scroll and a high-pressure side rotation prevention mechanism for preventing the rotation of the orbiting scroll are provided. Scroll type fluid machine characterized by   The seal member includes an annular concave groove provided on the outer peripheral side of the output shaft of the electric motor, an elastic ring accommodated in the concave groove, and an annular band member provided on the outer peripheral side of the elastic ring. The scroll fluid machine according to claim 1, which is configured.   The scroll type fluid machine according to claim 1 or 2, wherein the low pressure side eccentric bush weight and the high pressure side eccentric bush weight are attached to the same position in the circumferential direction with respect to the output shaft of the electric motor.   4. The scroll fluid machine according to claim 1, wherein the casing, the output shaft of the electric motor, the eccentric bush weight, and the rotation prevention mechanism are arranged symmetrically on the low-pressure side and the high-pressure side.   The scroll fluid machine according to claim 1, 2, 3, or 4, wherein the rotation prevention mechanism is constituted by a ball coupling mechanism having a sphere that rolls on a specified arc.

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