JP4303095B2 - Scroll type fluid machine - Google Patents

Description

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

  In general, as a scroll type fluid machine, first and second fixed scrolls are provided in the casing in an axially spaced manner, an electric motor is disposed between the fixed scrolls, and the first and second fixed scrolls are disposed at both ends of the rotating shaft of the electric motor. There is known one provided with first and second orbiting scrolls respectively facing the first and second fixed scrolls (see, for example, Patent Document 1).

JP 2000-130365 A

  In such a conventional scroll type fluid machine, eccentric bearings composed of three members of an outer ring, an intermediate ring, and an inner ring are provided on both ends of a hollow rotating shaft. And while fixing the outer ring | wheel of each eccentric bearing to a casing and fixing the middle ring | wheel to a rotating shaft, the rotating shaft was supported rotatably with respect to the casing. Further, the inner ring of the eccentric bearing is mounted at a position eccentric from the center of the middle ring (the axis center of the rotating shaft), and rotatably supports the eccentric shaft disposed on the inner peripheral side of the rotating shaft. The eccentric shaft is configured to penetrate the rotating shaft in the axial direction and to be attached with the first and second orbiting scrolls at both ends thereof.

  In this prior art, when the electric motor is driven to rotate, the first and second orbiting scrolls orbit with a certain eccentric dimension with respect to the first and second fixed scrolls. As a result, while fluid such as air is sucked from the suction port provided on the outer peripheral side of each fixed scroll, this fluid is sequentially compressed and fixed in each compression chamber between the wrap portion of the fixed scroll and the wrap portion of the orbiting scroll. The configuration is such that the compressed fluid is discharged outward from a discharge port provided in the center of the scroll.

  By the way, in the scroll type fluid machine according to the prior art described above, the compressed fluid leaks from the compression chamber between the wrap portions while preventing the wrap portion of the fixed scroll and the wrap portion of the orbiting scroll from coming into contact (galling). In order to prevent this, it is necessary to set the amount of eccentricity between the rotating shaft and the eccentric shaft with high accuracy. In contrast, the conventional technology uses an eccentric bearing in which the outer ring, the middle ring, and the inner ring are arranged in a triple cylinder (on the same plane), so the machining accuracy of the outer ring, middle ring, and inner ring is all superimposed on the amount of eccentricity. To affect. That is, there is a problem that it is difficult to set the eccentricity with high accuracy because the position of the inner ring must be defined with respect to the middle wheel and the outer ring must be defined with respect to the middle wheel.

  Further, in the eccentric bearing according to the prior art, two holes, that is, an attachment hole for fixing and attaching to the rotary shaft and an accommodation hole for accommodating the inner ring are machined on the inner peripheral side of the middle wheel. At this time, the mounting hole and the accommodation hole are displaced from each other by an amount of eccentricity, and the opening portions are different from each other. Therefore, it is necessary to process these two holes from both sides (right and left sides) in the axial direction of the middle wheel. At this time, since the hole is machined by changing the middle wheel between the right side and the left side, the center of the shaft tends to be displaced when the middle wheel is changed, and the accuracy of the hole machining tends to be lowered. On the other hand, in order to prevent misalignment of the center of the shaft, when the middle wheel is moved and fixed, if the middle wheel is positioned with high accuracy and attached to a processing machine such as a lathe, it takes a long time for alignment. Since it is necessary, there is a problem that the processing time becomes long, resulting in a decrease in productivity and an increase in manufacturing cost.

  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 provide a scroll type fluid machine capable of setting an eccentricity with high accuracy and improving productivity. There is.

  In order to solve the above-described problem, the invention of claim 1 includes a casing, a fixed scroll that is positioned on the axis of the casing and is fixedly provided on the casing, and a spiral wrap portion is erected on the end plate. An electric motor provided in the casing and having a rotor and a stator arranged in the same direction as an axis of the casing, a rotary shaft provided on an inner peripheral side of the electric motor and rotating with the rotor, An eccentric shaft provided on the inner peripheral side of the rotary shaft and eccentric with respect to the axis of the casing, and a plurality of compression chambers provided on the eccentric shaft and facing the fixed scroll and overlapping a lap portion of the fixed scroll on the end plate A scroll type fluid machine comprising a orbiting scroll having a wrap portion standing upright, a rotary bearing that rotatably supports the rotary shaft and the eccentric shaft, and an eccentric bearing. The rotating shaft is provided with a bearing fixing shaft whose inner peripheral side is attached to the rotating shaft and rotationally moves with the rotating shaft, and the eccentric bearing is disposed between the inner peripheral side of the bearing fixing shaft and the eccentric shaft. The rotating bearing is provided between the outer peripheral side of the rotating shaft and the casing at a position different from the bearing fixing shaft in the axial direction.

  The invention according to claim 2 is the first and second fixed parts in which the casing and the first and second fixed parts are fixedly provided on both end sides of the casing and located on the axis of the casing. An electric motor provided in the casing, located between the scroll and the first and second fixed scrolls, and arranged such that the rotor and the stator are in the same direction as the axis of the casing; A rotating shaft that is provided on the circumferential side and that rotates with the rotor; an eccentric shaft that is provided on the inner circumferential side of the rotating shaft and that is eccentric with respect to the axis of the casing; and that is provided on both ends of the eccentric shaft, First and second swivels in which a wrap portion that faces the first and second fixed scrolls and that overlaps with the wrap portions of the first and second fixed scrolls on the end plate and defines a plurality of compression chambers is erected. Scroll and said In a scroll fluid machine including a rotary shaft and a rotary bearing that rotatably supports an eccentric shaft and an eccentric bearing, inner ends are attached to the rotary shaft at both ends of the rotary shaft and rotate together with the rotary shaft. A moving bearing fixed shaft is provided, the eccentric bearing is provided between the inner peripheral side of the bearing fixed shaft and the eccentric shaft, and the rotary bearing is located at a position different from the bearing fixed shaft in the axial direction. It is characterized by having a structure provided between the outer peripheral side and the casing.

  According to a third aspect of the present invention, the bearing fixed shaft communicates with the rotary shaft fitting hole in a state of being eccentric with the rotary shaft fitting hole into which the rotary shaft is fitted, and the eccentric shaft. An eccentric bearing fitting hole into which the bearing is fitted is provided.

  According to a fourth aspect of the present invention, the eccentric bearing fitting hole is formed to have a larger diameter than the rotating shaft fitting hole, and the opening surface of the rotating shaft fitting hole is disposed inside the opening surface of the eccentric bearing fitting hole. is doing.

  In the invention of claim 5, the eccentric shaft has an outer peripheral side formed in a straight shape.

  According to a sixth aspect of the present invention, the bearing fixed shaft is provided with a cooling fan for cooling the orbiting scroll on the outer peripheral side thereof.

  According to the first aspect of the invention, since the eccentric shaft is attached to the rotary shaft using the eccentric bearing and the bearing fixed shaft, the eccentric amount of the eccentric shaft is set according to the machining accuracy of the bearing fixed shaft. At this time, the bearing fixed shaft is provided with a rotating shaft and an eccentric bearing on the inner peripheral side thereof, and the rotating shaft is supported by using rotating bearings arranged at different positions in the axial direction of the bearing fixed shaft. Only the machining accuracy on the inner peripheral side of the bearing fixed shaft needs to be increased, and unlike the central shaft of the conventional eccentric bearing, the outer peripheral side of the bearing fixed shaft is not involved in the eccentric amount. As a result, it is possible to easily set the eccentric amount of the eccentric shaft with high accuracy by drilling the inner peripheral side of the bearing fixed shaft with high accuracy. It is possible to prevent galling with the wrap portion, improve reliability and durability, and improve compression efficiency.

  According to the second aspect of the invention, the eccentric bearings provided at both ends of the rotating shaft support the eccentric shaft rotatably with a certain amount of eccentricity, and the first and second orbiting scrolls are provided at both ends of the eccentric shaft. Even if the accuracy of the mounting position of any one of the eccentric bearings provided on both ends of the rotating shaft is lowered, the wrap portion of the first and second fixed scrolls and the first and second orbiting scrolls are provided. There is a tendency for galling or the like to occur between the lap portion. On the other hand, in the invention of claim 2, bearing fixed shafts are provided at both ends of the rotary shaft, each of these bearing fixed shafts is provided with a rotary shaft and an eccentric bearing on its inner peripheral side, and the rotary shaft is each bearing fixed shaft. It is set as the structure supported using the rotary bearing arrange | positioned in the position where an axial direction differs. For this reason, the outer peripheral side of the bearing fixed shaft is not involved in the amount of eccentricity, and if only the processing accuracy on the inner peripheral side of the bearing fixed shaft is increased, the eccentric amount of the eccentric shaft can be set with high accuracy. As a result, the amount of eccentricity of the eccentric shaft can be easily set with high accuracy by performing hole machining or the like on the inner peripheral side of both bearing fixed shafts. It is possible to prevent the wrap portion of the fixed scroll and the wrap portions of the first and second orbiting scrolls from being squeezed, thereby improving reliability and durability, and improving compression efficiency.

  According to the invention of claim 3, since the bearing fixed shaft is configured to include the rotating shaft fitting hole into which the rotating shaft is fitted and the eccentric bearing fitting hole into which the eccentric bearing is fitted. The eccentric shaft can be decentered by the amount of eccentricity with respect to the axis of the rotating shaft. For this reason, the amount of eccentricity can be set accurately by increasing the accuracy of the hole machining of the rotary shaft fitting hole and the eccentric bearing fitting hole.

  According to the invention of claim 4, the eccentric bearing fitting hole is formed larger in diameter than the rotating shaft fitting hole, and the opening surface of the rotating shaft fitting hole is arranged inside the opening surface of the eccentric bearing fitting hole. Therefore, after drilling the eccentric bearing fitting hole, drilling the rotary shaft fitting hole, the bearing fixed shaft can be formed by drilling from one axial direction, and the axial direction as in the prior art Drilling from both sides is not necessary. As a result, it is possible to prevent the hole machining accuracy from being lowered due to the change of the bearing fixed shaft, and the rotary shaft fitting hole and the eccentric bearing fitting hole can be easily machined with high accuracy. In addition, since the processing time of the bearing fixed shaft can be shortened, productivity can be increased and manufacturing cost can be reduced.

  According to the invention of claim 5, since the outer peripheral side of the eccentric shaft is formed in a straight shape, the eccentric shaft can be processed with high accuracy using, for example, a lathe. For this reason, the amount of eccentricity can be set with high accuracy by attaching such an eccentric shaft to the eccentric bearing.

  According to the invention of claim 6, since the cooling fan is provided on the outer peripheral side of the bearing fixed shaft, when the bearing fixed shaft is driven to rotate together with the rotating shaft, the cooling fan is used to generate cooling air, The orbiting scroll disposed between the fixed scroll and the fixed scroll can be cooled. In particular, in the present invention, the outer peripheral side of the bearing fixed shaft is not fixed or supported by the casing, the rotating shaft, or the like so that the outer peripheral side of the bearing fixed shaft is not involved in the eccentric amount. For this reason, a cooling fan can be easily attached with respect to the outer peripheral side of such a bearing fixed shaft.

  Hereinafter, the scroll fluid machine according to the embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4 by taking as an example a case where the scroll fluid machine is applied to a twin-wrap scroll air compressor.

  In the figure, reference numeral 1 denotes a cylindrical casing forming an outer frame of a scroll type air compressor. The casing 1 includes a casing main body 2 formed in a substantially cylindrical shape centering on an axis O 1 -O 1, and the casing main body 2. The right and left bearing mounting bodies 3A and 3B are provided to be fixed to the right and left both end sides, respectively. And the casing 1 comprises the fixed side member with the below-mentioned fixed scroll 5A, 5B.

  Here, the bearing mounting body 3A located on one side (the right side in FIG. 1) of the casing main body 2 constitutes a low-pressure scroll portion 4A which becomes a low-pressure stage compression portion together with a fixed scroll 5A, a turning scroll 25A and the like which will be described later. It is. Further, the bearing mounting body 3B located on the other side (the left side in FIG. 1) of the casing main body 2 constitutes a high-pressure scroll portion 4B serving as a high-pressure stage compression portion together with a fixed scroll 5B, a turning scroll 25B and the like described later. .

  Note that the low-pressure scroll unit 4A and the high-pressure scroll unit 4B have substantially the same components, and therefore, in the following description, the low-pressure stage is denoted by the symbol “A”, and the high-pressure stage is denoted by the symbol “B. "Will be described. Further, in order to avoid overlapping description between the low-pressure stage and the high-pressure stage, the components of the low-pressure scroll unit 4A will be mainly described, and the description of the components of the high-pressure scroll unit 4B will be omitted.

  5A is a low-pressure stage fixed scroll provided on the bearing mounting body 3A side of the casing 1, and the fixed scroll 5A has a substantially disc-like shape with its center aligned with the axis O1-O1 of the casing 1. End plate 6A, a spiral wrap portion 7A standing on the surface of the end plate 6A, a cylindrical portion 8A protruding in the axial direction so as to surround the wrap portion 7A from the outer peripheral side of the end plate 6A, and the cylindrical portion The flange portion 9A protrudes radially outward from the outer peripheral side of 8A.

  The fixed scroll 5A is detachably mounted on the outer peripheral side of the flange portion 9A on the opening side of the bearing mounting body 3A via a bolt or the like. Further, the end plate 6A of the fixed scroll 5A is provided with a suction port 10A for sucking a fluid such as air (outside air) into a compression chamber 29A, which will be described later, at a position closer to the outer periphery, and the center side (axis O1) of the end plate 6A. -O1) is provided with a discharge port 11A for compressed air.

  An electric motor 12 is located between the low-pressure stage fixed scroll 5A and the high-pressure stage fixed scroll 5B and serves as driving means provided in the casing body 2. The electric motor 12 has an inner periphery of the casing body 2. A cylindrical stator 13 fixed to the side and a cylindrical rotor 14 rotatably disposed on the inner peripheral side of the stator 13 are configured.

  Here, in the electric motor 12, the axes of the stator 13 and the rotor 14 are arranged on the same axis as the axis O 1 -O 1 of the casing 1. The electric motor 12 rotates the rotor 14 described later by rotating the rotor 14 around the axis O1-O1.

  Reference numeral 15 denotes a rotating shaft provided in the axial direction through the rotor 14 of the electric motor 12, and the rotating shaft 15 is fitted into the rotor 14 of the electric motor 12 by means of press fitting or the like. And is rotated integrally with the rotor 14 about the axis O1-O1. The rotary shaft 15 is rotatably provided on the inner peripheral side of the bearing mounting bodies 3A and 3B on the right and left sides of the casing 1 using rotary bearings 24A and 24B, which will be described later. An insertion hole 16 for inserting an eccentric shaft 23 described later is formed. The rotating shaft 15 constitutes an output shaft of the electric motor 12 together with the eccentric shaft 23.

  Reference numeral 17A denotes an eccentric drive bushing as a bearing fixed shaft attached to the right end (low pressure scroll portion 4A side) of the rotary shaft 15, and the eccentric drive bush 17A is formed in a substantially cylindrical shape as shown in FIGS. A rotary shaft fitting hole 18A for fitting the rotary shaft 15 on the inner peripheral side thereof, and an eccentric bearing fit for fitting an eccentric bearing 22A described later in communication with the rotary shaft fitting hole 18A. A joint hole 19A is formed.

  The rotation shaft fitting hole 18A has a constant diameter dimension Ds that is substantially the same as the outer diameter dimension of the rotation shaft 15 with respect to the shaft center (axis line O1-O1) of the eccentric drive bush 17A. For example, it is fitted by means such as press fitting. Thereby, the eccentric drive bush 17A is fixed to the rotary shaft 15 and is rotationally driven together with the rotary shaft 15.

  On the other hand, the eccentric bearing fitting hole 19A is larger in diameter than the rotary shaft fitting hole 18A and has a diameter dimension Db that is substantially the same as the outer diameter dimension of the eccentric bearing 22A, and its center is the axis center of the eccentric drive bush 17A. Therefore, it is eccentric by the dimension δ (the amount of eccentricity δ). The diameters Db and Ds of the rotating shaft fitting hole 18A and the eccentric bearing fitting hole 19A satisfy the relationship shown in the following formula 1, and the opening surface of the rotating shaft fitting hole 18A is the eccentric bearing fitting hole 19A. It is arrange | positioned inside the opening surface. As a result, as shown in FIG. 4, the opening surface of the rotary shaft fitting hole 18A has no portion protruding from the opening surface of the eccentric bearing fitting hole 19A, and these opening surfaces overlap over the entire surface. The rotating shaft fitting hole 18A penetrates the rotating shaft 15 in the axial direction together with the eccentric bearing fitting hole 19A.

  As shown in FIG. 1, a cooling fan 20A is mounted on the outer peripheral side of the eccentric drive bush 17A. The cooling fan 20A has an eccentric drive using a key member 21 whose hub portion (rotation center portion) is used for stopping rotation. It is fixed to the bush 17A and is driven to rotate together with the rotary shaft 15. Thereby, the cooling fan 20A supplies cooling air to the back surface (back surface) side of the end plate 26A of the orbiting scroll 25A described later, thereby cooling the orbiting scroll 25A.

  22A is an eccentric bearing provided between the inner peripheral side of the eccentric drive bush 17A and an eccentric shaft 23 described later. The eccentric bearing 22A has an outer diameter dimension substantially the same as the diameter dimension Db of the eccentric bearing fitting hole 19A. And fitted, fixed and accommodated in the eccentric bearing fitting hole 19A. The eccentric bearing 22A has an eccentric shaft 23 inserted therein together with the eccentric bearing 22B, and rotatably supports the eccentric shaft 23 at a position eccentric from the axis O1-O1 by the dimension δ.

  An eccentric shaft 23 is provided in the insertion hole 16 of the rotary shaft 15 so as to be relatively rotatable. The eccentric shaft 23 is formed as a solid shaft body and has a dimension δ with respect to the axis O1-O1 of the casing 1 or the like. It is arranged on the eccentric axis O2-O2 which is eccentric only by the distance. Further, the eccentric shaft 23 is formed in a straight shape (straight shape) with no step on the outer peripheral side in the axial direction. The eccentric shaft 23 is attached to the rotary shaft 15 so as to be relatively rotatable in the insertion hole 16 of the rotary shaft 15 using the eccentric bearings 22A and 22B, and constitutes an output shaft of the electric motor 12 together with the rotary shaft 15. Yes.

  Further, both ends of the eccentric shaft 23 in the axial direction protrude in the axial direction from both ends of the rotary shaft 15 (insertion hole 16), and orbiting scrolls 25A and 25B, which will be described later, are provided on the protruding end side so as to be spaced apart to the right and left. It has been. The eccentric shaft 23 follows the rotation of the rotary shaft 15 to give the orbiting scrolls 25A and 25B a turning motion.

  Reference numeral 24A denotes a rotary bearing provided on the outer periphery of the rotary shaft 15. The rotary bearing 24A is disposed between the eccentric drive bush 17A and the rotor 14 at a position different from the eccentric drive bush 17A in the axial direction. The rotary bearing 24A is mounted adjacent to the eccentric drive bush 17A between the outer peripheral side of the rotary shaft 15 and the bearing mounting body 3A (casing 1). The rotary shaft 15 is attached to the casing 1 together with the rotary bearing 24B. It is supported so as to be rotatable about the axis O1-O1.

  25A is a low-pressure stage orbiting scroll provided facing the fixed scroll 5A in the casing 1, and the low-pressure stage orbiting scroll 25A includes an end plate 26A formed in a substantially disc shape, and the end plate 26A. And a spiral wrap portion 27A provided upright on the surface. The orbiting scroll 25B in the high-pressure stage is also roughly constituted by an end plate 26B formed in a substantially disc shape and a spiral wrap portion 27B.

  Here, in the low-pressure stage and high-pressure stage orbiting scrolls 25A and 25B, the center portions on the back side of the end plates 26A and 26B are integrally fixed to both ends of the eccentric shaft 23 using bolts (not shown), respectively. A turning operation is performed together with the eccentric shaft 23 by the driving force from the motor 12. The orbiting scrolls 25A and 25B are arranged so that the wrap portions 27A and 27B are overlapped with the wrap portions 7A and 7B of the fixed scrolls 5A and 5B by shifting by a predetermined angle (for example, 180 degrees), and as an anti-rotation mechanism. The auxiliary crank 28 is used to prevent the rotation.

  The low-pressure stage fixed scroll 5A and the orbiting scroll 25A define low-pressure stage compression chambers 29A, 29A,... Between the lap portions 7A and 27A from the outer peripheral side to the inner peripheral side. The high-pressure stage fixed scroll 5B and the orbiting scroll 25B define high-pressure stage compression chambers 29B, 29B,... Between the lap portions 7B and 27B from the outer peripheral side to the inner peripheral side. The low-pressure stage discharge port 11A and the high-pressure stage suction port 10B are connected using, for example, a conduit (not shown), and are configured to perform two-stage compression using the two scroll portions 4A and 4B. .

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

  First, when the rotor 14 is rotationally driven by energizing the stator 13 side of the electric motor 12, the cylindrical rotary shaft 15 integrated with the rotor 14 rotates integrally with the rotor 14 about the axis O1-O1. .

  Then, the eccentric shaft 23 arranged on the eccentric axis O 2 -O 2 performs a turning motion with a turning radius of the dimension δ within the insertion hole 16 of the rotating shaft 15 by the rotation of the rotating shaft 15. Thereby, the orbiting scrolls 25A and 25B provided on both ends of the eccentric shaft 23 perform the orbiting operation with the orbiting radius of the dimension δ with respect to the fixed scrolls 5A and 5B.

  For this reason, on the low pressure scroll portion 4A side, the air is sequentially compressed in each compression chamber 29A while sucking outside air from a suction port 10A provided on the outer peripheral side of the fixed scroll 5A through a suction filter (not shown). . The compressed air compressed to a pressure of, for example, about 0.3 to 0.4 MPa in the compression chamber 29A between the low-pressure stage fixed scroll 5A and the orbiting scroll 25A is provided at the center of the fixed scroll 5A. It discharges toward the inside of a conduit (not shown) from discharge port 11A.

  On the high-pressure scroll unit 4B side, compressed air at this time is supplied to the suction port 10B of the fixed scroll 5B through a conduit. The compressed air at this time is further compressed in each compression chamber 29B between the high-pressure stage fixed scroll 5B and the orbiting scroll 25B, and the compressed air compressed to a pressure of about 1.0 MPa, for example, is fixed to the fixed scroll. It is discharged toward the outside from a discharge port 11B provided at the center of 5B, and is stored in, for example, an air tank (not shown).

  However, in the present embodiment, the eccentric shaft 23 is attached to the rotary shaft 15 using the eccentric bearings 22A and 22B and the eccentric drive bushes 17A and 17B, and therefore, the eccentric shaft according to the machining accuracy of the eccentric drive bushes 17A and 17B. 23 eccentricity (dimension δ) is set. At this time, the eccentric drive bushes 17A and 17B are provided with the rotary shaft 15 and the eccentric bearings 22A and 22B on the inner peripheral side thereof, and the rotary shaft 15 rotates at a position different from the eccentric drive bushes 17A and 17B in the axial direction. Since it is configured to be supported using the bearings 24A and 24B, it is only necessary to increase the machining accuracy on the inner peripheral side of the eccentric drive bushes 17A and 17B. Unlike the center shaft of the conventional eccentric bearing, the eccentric drive bush 17A is required. , 17B is not involved in the amount of eccentricity. As a result, the amount of eccentricity of the eccentric shaft 23 can be easily set with high accuracy by drilling the inner peripheral side of the eccentric drive bushes 17A, 17B with high accuracy, and the fixed scrolls 5A, 5B. The wrap portions 7A and 7B and the wrap portions 27A and 27B of the orbiting scrolls 25A and 25B can be prevented from being squeezed to improve reliability and durability, and improve compression efficiency.

  In particular, in the present embodiment, the eccentric bearings 22A and 22B provided on both ends of the rotating shaft 15 rotatably support the eccentric shaft 23 with a certain amount of eccentricity, and the turning scrolls 25A and 25A on both ends of the eccentric shaft 23, respectively. Since 25B is provided, even when the accuracy of the mounting position of either one of the eccentric bearings 22A and 22B provided on both ends of the rotary shaft 15 is lowered, the wrap portions 7A and 7B of the fixed scrolls 5A and 5B and the orbiting scroll There is a tendency that galling or the like occurs between the wrap portions 27A and 27B of 25A and 25B.

  On the other hand, in the present embodiment, eccentric drive bushes 17A and 17B are provided at both ends of the rotary shaft 15, and each of the eccentric drive bushes 17A and 17B has a rotary shaft 15 and eccentric bearings 22A and 22B on the inner peripheral side thereof. The rotary shaft 15 is supported by the rotary drive bushes 17A and 17B and rotary bearings 24A and 24B arranged at different positions in the axial direction. For this reason, since the outer peripheral side of the eccentric drive bushes 17A and 17B is not involved in the eccentric amount, the hole of the eccentric shaft 23 of the eccentric drive bushes 17A and 17B is drilled with high accuracy and the like. The amount of eccentricity can be easily set with high accuracy, and the wrap portions 7A and 7B of the fixed scrolls 5A and 5B and the wrap portions 27A of the orbiting scrolls 25A and 25B are provided for both the right and left scroll portions 4A and 4B. , 27B can be prevented.

  Further, the eccentric drive bushes 17A and 17B are configured to include rotary shaft fitting holes 18A and 18B into which the rotary shaft 15 is fitted and eccentric bearing fitting holes 19A and 19B into which the eccentric bearings 22A and 22B are fitted. Therefore, by shifting the positions of these centers by the amount of eccentricity (dimension δ), the eccentric shaft 23 can be eccentric by the amount of eccentricity with respect to the axis of the rotating shaft 15 (axis line O1-O1). For this reason, the amount of eccentricity can be set accurately by increasing the accuracy of the hole machining of the rotary shaft fitting holes 18A and 18B and the eccentric bearing fitting holes 19A and 19B.

  The rotary shaft fitting holes 18A, 18B and the eccentric bearing fitting holes 19A, 19B communicate with each other and pass through the eccentric drive bushes 17A, 17B, and the eccentric bearing fitting holes 19A, 19B are the rotary shaft fitting holes. 18A and 18B are formed to have a larger diameter, and the opening surfaces of the rotary shaft fitting holes 18A and 18B are disposed inside the opening surfaces of the eccentric bearing fitting holes 19A and 19B. Therefore, the eccentric bearing fitting holes 19A and 19B are provided. By drilling the rotary shaft fitting holes 18A and 18B after drilling, the eccentric drive bushings 17A and 17B can be formed by drilling from one axial side. As a result, since drilling from both sides in the axial direction is not required as in the prior art, it is possible to prevent a decrease in drilling accuracy associated with the change of the eccentric drive bushings 17A, 17B, and the rotary shaft fitting holes 18A, 18B. The eccentric bearing fitting holes 19A and 19B can be easily drilled with high accuracy. Moreover, since the machining time of the eccentric drive bushes 17A and 17B can be shortened, the productivity can be increased and the manufacturing cost can be reduced.

  Moreover, since the outer peripheral side of the eccentric shaft 23 is formed in a straight shape, it is not necessary to change both ends of the eccentric shaft 23, and the eccentric shaft 23 can be processed with high accuracy using, for example, a lathe. For this reason, the eccentric amount can be set with high accuracy by attaching the eccentric shaft 23 to the eccentric bearings 22A and 22B.

  Further, since the cooling fans 20A and 20B are attached to the outer peripheral sides of the eccentric drive bushes 17A and 17B, when the eccentric drive bushes 17A and 17B are rotationally driven together with the rotary shaft 15, the cooling fans 20A and 20B are used to And the orbiting scrolls 25A and 25B arranged between the electric motor 12 and the fixed scrolls 5A and 5B can be cooled.

  In particular, in the present embodiment, the outer peripheral sides of the eccentric drive bushings 17A and 17B are not fixed or supported by the casing 1, the rotary shaft 15 or the like so that the outer peripheral sides of the eccentric drive bushings 17A and 17B are not involved in the eccentricity. It is in an open state. For this reason, the cooling fans 20A and 20B can be easily attached to the outer peripheral sides of the eccentric drive bushes 17A and 17B.

  In the embodiment, the casing 1 and the fixed scrolls 5A and 5B are formed as separate bodies, and the fixed scrolls 5A and 5B are fixed to both ends of the casing 1 using bolts or the like. I gave it as an explanation. However, the present invention is not limited to this. For example, the casing 1 and the fixed scrolls 5A and 5B may be integrally formed in advance, and thereby the fixed-side member may be configured.

  In the above embodiment, the outer peripheral side of the eccentric shaft 23 is formed in a straight shape, and one end side of the eccentric shaft is fixed to, for example, a lathe chuck, and can be processed with high accuracy. However, the present invention is not limited to this, and any portion of the eccentric shaft that is rotatably supported by the eccentric bearing may be formed with high accuracy. For example, the axial center portion of the eccentric shaft is supported by the eccentric bearing. The structure formed in a small diameter may be sufficient as compared with the both ends. In this case, after the outer periphery of the eccentric shaft is formed, a step is provided by post-processing the axial center portion of the eccentric shaft.

  In the above embodiment, the twin wrap type scroll type air compressor for two-stage compression has been described as an example. However, the present invention is not limited to this. For example, in order to obtain a large air volume, two single-stage compressors provided on both sides of the electric motor may be connected in parallel.

  In the above-described embodiment, the twin-wrap type two-stage scroll type air compressor has been described as an example. However, the present invention is not limited to this. For example, the present invention may be applied to a single-stage scroll type air compressor in which one of the two scroll portions 4A and 4B is eliminated.

  Furthermore, in the said embodiment, the scroll type air compressor was mentioned as an example and demonstrated as a 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.

It is a longitudinal section showing a scroll type air compressor by an embodiment of the invention. FIG. 2 is a perspective view showing a single body in an enlarged state of an eccentric drive bush in FIG. 1. It is a longitudinal cross-sectional view which shows the eccentric drive bush in FIG. FIG. 4 is a side view showing an eccentric drive bush as seen from the direction of arrows IV-IV in FIG. 3.

Explanation of symbols

1 Casing (fixed side member)
4A Low pressure scroll unit (low pressure stage compression unit)
4B High pressure scroll part (high pressure stage compression part)
5A, 5B Fixed scroll 6A, 6B, 26A, 26B End plate 7A, 7B, 27A, 27B Lapping part 12 Electric motor (electric motor)
13 Stator 14 Rotor 15 Rotating shaft 17A, 17B Eccentric drive bush (bearing fixed shaft)
18A, 18B Rotating shaft fitting hole 19A, 19B Eccentric bearing fitting hole 20A, 20B Cooling fan 22A, 22B Eccentric bearing 23 Eccentric shaft 24A, 24B Rotating bearing 25A, 25B Orbiting scroll 28 Auxiliary crank (rotation prevention mechanism)
29A, 29B compression chamber

Claims (6)

A casing,
A fixed scroll positioned on the casing axis fixedly provided on the casing and having a spiral wrap portion standing on the end plate;
An electric motor provided in the casing and disposed so that the rotor and the stator are in the same direction as the axis of the casing;
A rotating shaft that is provided on the inner peripheral side of the electric motor and rotates with the rotor;
An eccentric shaft provided on the inner peripheral side of the rotating shaft and eccentric with respect to the axis of the casing;
A orbiting scroll provided on the eccentric shaft and provided with a wrap portion standing on the end plate facing the fixed scroll so as to overlap the wrap portion of the fixed scroll and defining a plurality of compression chambers;
In a scroll type fluid machine comprising a rotary bearing and an eccentric bearing that rotatably support the rotating shaft and the eccentric shaft,
The rotating shaft is provided with a bearing fixing shaft whose inner peripheral side is attached to the rotating shaft and rotates together with the rotating shaft,
The eccentric bearing is provided between the inner peripheral side of the bearing fixed shaft and the eccentric shaft,
The scroll type fluid machine, wherein the rotary bearing is provided between an outer peripheral side of the rotary shaft and a casing at a position different in the axial direction from the bearing fixed shaft. A casing,
First and second fixed scrolls, which are positioned on the axis of the casing and fixedly provided on both ends of the casing, respectively, and a spiral wrap portion is erected on the end plate;
An electric motor located between the first and second fixed scrolls and provided in the casing, the rotor and the stator being arranged in the same direction as the axis of the casing;
A rotating shaft that is provided on the inner peripheral side of the electric motor and rotates with the rotor;
An eccentric shaft provided on the inner peripheral side of the rotating shaft and eccentric with respect to the axis of the casing;
Wrap portions provided on both ends of the eccentric shaft, respectively, facing the first and second fixed scrolls and overlapping the wrap portions of the first and second fixed scrolls on the end plate to define a plurality of compression chambers And the first and second orbiting scrolls,
In a scroll type fluid machine comprising a rotary bearing and an eccentric bearing that rotatably support the rotating shaft and the eccentric shaft,
Provided at both ends of the rotating shaft are bearing fixed shafts whose inner peripheral side is attached to the rotating shaft and rotates together with the rotating shaft,
The eccentric bearing is provided between the inner peripheral side of the bearing fixed shaft and the eccentric shaft,
The scroll type fluid machine, wherein the rotary bearing is provided between an outer peripheral side of the rotary shaft and a casing at a position different in the axial direction from the bearing fixed shaft.   The bearing fixed shaft includes a rotation shaft fitting hole into which the rotation shaft is fitted, and an eccentricity into which the eccentric bearing is fitted in communication with the rotation shaft fitting hole in an eccentric state with the rotation shaft fitting hole. The scroll type fluid machine according to claim 1 or 2, comprising a bearing fitting hole.   The eccentric bearing fitting hole is formed to have a larger diameter than the rotating shaft fitting hole, and the opening surface of the rotating shaft fitting hole is disposed inside the opening surface of the eccentric bearing fitting hole. The scroll type fluid machine as described.   The scroll type fluid machine according to claim 1, 2, 3, or 4, wherein the eccentric shaft is formed in a straight shape on an outer peripheral side thereof.   The scroll fluid machine according to claim 1, 2, 3, 4 or 5, wherein the bearing fixing shaft is provided with a cooling fan for cooling the orbiting scroll on an outer peripheral side thereof.

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