JP2009030705A - Gear supporting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the partial wear of gears by keeping a ring gear in constant engagement with other gears. <P>SOLUTION: This gear supporting structure comprises: the ring gear 20; a driving gear 16 engaging with the ring gear for rotationally driving the ring gear; a plurality of output gears 19 engaging with the ring gear for rotationally driving a plurality of output shafts, respectively; a casing storing the ring gear, the driving gear and the output gears; and rolling elements 21 arranged on the side faces of the output gears rotatably relative to the output shafts. The rolling elements have portions contacting part of the ring gear for supporting the ring gear via the portions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gear support structure, and more particularly, to a gear support structure that can keep the meshing of a gear constant.

  The centrifugal compressor is provided with an impeller for compressing gas and a main shaft that rotates integrally with the impeller, and compresses the gas sucked into the casing by rotating the main shaft. In recent years, for the purpose of improving the performance of a centrifugal compressor, a flow rate adjusting mechanism for adjusting a gas suction amount has been provided.

  As a centrifugal compressor having a flow rate adjusting mechanism, for example, a centrifugal compressor described in Patent Document 1 or Patent Document 2 is known.

  In the centrifugal compressor described in Patent Document 1, as the flow rate adjusting mechanism, a plurality of suction vanes that can swing in a plane substantially perpendicular to the axis of the main shaft are arranged in the inflow path so as to surround the periphery of the main shaft. By changing the angle of the suction vane with respect to the main shaft, the amount of gas supplied from the inflow path to the impeller (that is, the amount of gas sucked from the suction port) can be adjusted.

  The suction vane has an attachment shaft extending in parallel with the main shaft, and a vane gear is coaxially provided on the attachment shaft. Around the main shaft, it is arranged closer to the main shaft than the vane gear, meshes with each vane gear and is rotatable around the main shaft, and meshes with one of the vane gears and parallel to the main shaft And a drive gear having a drive shaft extending through the casing.

  That is, the drive gear, the vane gear and the ring gear meshing with the drive gear are arranged in the radial direction of the main shaft. And if a drive gear is rotated via a drive shaft by the gear drive part provided in the outer side of the casing, the vane gear which meshes with the drive gear among the vane gears will rotate. When the vane gear rotates, the ring gear that meshes with the vane gear also rotates, and the other vane gear that meshes with the ring gear also rotates.

  In the centrifugal compressor described in Patent Document 2, a drive gear having a drive shaft and a ring gear mesh with each other, and when the drive gear is rotated, the ring gear rotates. When the ring gear rotates, a plurality of vane gears meshing with the ring gear rotate.

In these centrifugal compressors, the direction of the suction vane connected to the vane gear is adjusted using the vane gear, the drive gear, and the ring gear, and the meshing portion of each gear is filled with grease. ing.
JP 2001-295595 A JP 2006-233901 A

  In the device of Patent Document 1, since the meshing portion is provided on the outer peripheral side of the ring gear and the drive gear and the vane gear are arranged side by side in the radial direction, an installation place is required in the radial direction. In order to reduce the size in the radial direction, it is desirable to dispose the vane gear inside the ring gear. By arranging in this way, the drive gear and the vane gear can be arranged inside and outside the ring gear, and the size in the radial direction can be reduced. However, since the ring gear is supported by the vane gear in this case, the load applied to the vane gear is different between the upper portion and the lower portion of the ring gear. Also, lubrication with grease or the like cannot be obtained sufficiently in an extremely low temperature atmosphere. For this reason, there is a concern about the occurrence of uneven wear in each gear.

  The present invention has been made in view of such a problem, and provides a gear support structure capable of suppressing uneven wear of a gear while maintaining constant meshing between a ring gear and another gear.

  In order to solve the above problems, the present invention employs the following means.

  A ring gear, a drive gear that meshes with the ring gear and rotationally drives the ring gear, a plurality of output gears that mesh with the ring gear and rotationally drive a plurality of output shafts, and the ring gear, drive gear, and output A casing for housing the gear, and a rolling element disposed on a side surface of the output gear so as to be rotatable with respect to the output shaft, the rolling element having a portion in contact with a part of the ring gear, To support the ring gear.

  Since the present invention has the above-described configuration, it is possible to keep the meshing between the ring gear and the other gear constant and suppress the uneven wear of the gear.

  Hereinafter, the best embodiment will be described with reference to the accompanying drawings. 1, 2 and 3 are views for explaining a first embodiment in which the gear support structure of the present invention is applied to a centrifugal compressor, FIG. 1 is a longitudinal sectional view, and FIG. 2 is a view showing details of a rolling element, FIG. 3 is a diagram showing details of the ring gear support structure.

  As shown in FIG. 1, the centrifugal compressor 11 passes through a flow path 14 provided in a casing 13 by rotating an impeller 12 attached to a main shaft (not shown) by a driving device (not shown). Then, the gas supplied to the impeller is compressed by the rotation of the impeller. The compressed gas passes through a discharge port (not shown) and is supplied to the outside.

  The centrifugal compressor is provided with a plurality of vanes 15 for controlling the flow rate of the gas in a flow path for introducing the gas to the impeller.

  The vane is swung around the vane shaft 18 by a gear mechanism. The gear mechanism includes a first gear (drive gear) 17 fixed to a drive shaft 16 connected to a drive mechanism (not shown), and a third gear (fixed to a vane shaft 18 that swings and drives the vane 15. A second gear (ring) which is interposed between the vane gear) 19 and the first and third gears and transmits the rotational driving force from the drive gear 17 to the third gear (vane gear) 19. Gear) 20.

  That is, these first, second, and third gears are arranged in series in the radial direction (in the order in which the driving force is transmitted), and the first gear meshes with the teeth provided on the outer peripheral side of the ring gear. A plurality of third gears are provided and mesh with teeth provided on the inner peripheral side of the ring gear.

  These gears 17, 19 and 20 are accommodated in the casing 13. The first gear 17 and the third gear 19 each have a rotation shaft (drive shaft 16 and vane shaft 18) and are rotatably supported by bearings 22 fixed in the casing.

  As shown in FIGS. 1 to 3, among the plurality of vane shafts 18 that support the third gear (vane gear) 19, for example, three vane shafts are made of resin-made rolling elements so as to sandwich the vane gear 19. 21 is fixed in the axial direction and attached rotatably.

  In this embodiment, PTFE (polytetrafluoroethylene) containing carbon fibers is used as the resin. This resin rolling element has an outer diameter smaller than that of the third gear (vane gear), and is adjusted to a size such that the vane gear and the ring gear mesh with each other with a pitch circle, and is in contact with the tooth tip of the ring gear. To support the ring gear.

  In the absence of this rolling element, the meshing vane gear is always pressed against the ring gear above the ring gear. On the other hand, the gap increases at the lower part of the ring gear. That is, since the ring gear is reciprocated only by a small angle, the contact state of the tooth surfaces differs among the gears and may cause uneven wear. However, as in this example, uneven wear can be prevented by supporting the inner peripheral side of the ring gear with a resin rolling element.

  FIG. 3 shows an enlarged view of the ring gear support structure. In the figure, the same parts as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 3, two resin-made rolling elements 21 are sandwiched between three vane shafts 18 among a plurality of vane shafts 18 that support a third gear (vane gear) 19. It fixed to the axial direction with the retaining ring 31, and was attached rotatably with respect to the vane shaft. The three vane shafts to which the resin rolling elements 21 are attached are preferably selected from a plurality of vane shafts 18 that support the third gear (vane gear) 19 at equal intervals.

  Thus, by making the rolling element 21 rotatable, the contact when the rolling element 21 comes into contact with the ring gear 20 can be set as rolling contact. Therefore, the ring gear can be supported without generating excessive torque.

  FIG. 4 is a diagram for explaining the second embodiment. FIG. 4 shows an enlarged view of the ring gear support structure. In the figure, the same parts as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

  In this example, as shown in FIG. 4, two resin-made rolling shafts are sandwiched between three vane shafts 18 among a plurality of vane shafts 18 that support a third gear (vane gear) 19. The moving body 21 is attached. At the time of attachment, as shown in FIG. 4, a bearing 41 is attached to the rolling element, and is fixed in the axial direction via the bearing 41 so as to be rotatably attached to the vane shaft. The three vane shafts to which the resin rolling elements 21 are attached are preferably selected from a plurality of vane shafts 18 that support the third gear (vane gear) 19 at equal intervals.

  As described above, the rolling element 21 is rotatably attached by the bearing 41, so that the contact with the ring gear can be a rolling contact even if the rolling element itself is made of a material having no slidability. For this reason, the ring gear can be supported without generating extra torque.

  5 and 6 are diagrams for explaining the third embodiment. FIG. 5 shows an enlarged view of the ring gear support structure, and FIG. 6 shows details of the support member 51. In the figure, the same parts as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

  In the example shown in FIGS. 1 to 4, a resin rolling element 21 is provided on the side surface of the vane gear 19, and the ring gear is supported by the rolling element 21. In the present embodiment, as shown in FIGS. 5 and 6, the support member 51 thus formed is formed by using the material obtained by adding a reinforcing material to the slidable PTFE to the casing 13. The member 51 was attached to the casing 13 so that the outer peripheral edge of the member 51 was in contact with the inner peripheral tooth tip of the ring gear 20.

  Thus, uneven wear of the gear can be prevented by supporting the inner peripheral side of the ring gear 20 in the radial direction by the outer peripheral side edge of the support member 51. In this example, support members 51 are arranged on both sides of the vane gear 19, and convex portions 51 a are provided on the side of the support member 51 that is not in contact with the vane gear. If comprised in this way, when the ring gear 20 moves to an axial direction, the axial movement of a ring gear can be restrict | limited by the convex part 51a of the said supporting member 51 attached to the casing 13. FIG.

  As described above, according to the present embodiment, since the hollow ring gear is supported by a member other than the gear, the load or meshing position of the tooth surface applied to the ring gear and the vane gear meshing with the gear is kept constant. be able to. Further, even in an extremely low temperature atmosphere, the meshing between the ring gear and each gear can be kept constant, and uneven wear of the gear can be suppressed.

  In addition, it is desirable that the rolling elements arranged in the vane gear have a lower hardness than the ring gear, and when a metal is used as the gear, a resin material is used as the rolling element. As the resin material, PTFE, PEEK (polyether ether ketone), PPS (polyphenylene sulfide), or the like having a low water absorption, or a composite material thereof, a reinforcing material, or a solid lubricant is particularly preferable. As the reinforcing material, fibrous, spherical, or flaky glass or carbon can be used. As the solid lubricant, molybdenum disulfide, graphite, or the like can be used.

  Moreover, a resin material can be used according to the use with respect to a rolling bearing or a plain bearing as a bearing. When a resin material is used for the slide bearing, resins such as PTFE, PEEK, and PPS can be used alone or in combination. A solid lubricant or a reinforcing material may be added to the slide bearing. The sliding bearing may have a structure in which a resin member such as PTFE including a reinforcing material or the like on the sliding surface and a member made of metal are combined. In addition, a sliding bearing in which copper or copper-based metal powder and a solid lubricant are mixed in the resin material can be provided. As the reinforcing material mixed in the resin portion of these slide bearings, fiber-like, spherical, flaky glass, carbon, or alumina can be used. Similarly, molybdenum disulfide, graphite, or the like can be used as the solid lubricant mixed in the resin portion.

It is a figure explaining 1st Embodiment which applied the gear support structure of this invention to the centrifugal compressor. It is a figure which shows the detail of a rolling element. It is a figure explaining the support structure of a ring gearwheel. It is a figure explaining 2nd Embodiment. It is a figure explaining 3rd Embodiment. It is a figure which shows the detail of a supporting member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Centrifugal compressor 12 Impeller 13 Casing 14 Flow path 15 Vane 16 Drive shaft 17 Drive gear 18 Vane shaft 19 Vane gear 20 Ring gear 21 Rolling element 22 Bearing 31 Retaining ring 41 Bearing 51 Support member

Claims (7)

Ring gear,
A drive gear that meshes with the ring gear and rotationally drives the ring gear;
A plurality of output gears that mesh with the ring gear and respectively drive the plurality of output shafts;
A casing that houses the ring gear, the drive gear, and the output gear;
A rolling element disposed on a side surface of the output gear so as to be rotatable with respect to the output shaft;
The rolling element includes a portion in contact with a part of the ring gear, and supports the ring gear through the portion. The gear support structure according to claim 1,
The said rolling element supports the front-end | tip part of the tooth | gear formed in the inner peripheral side of the said ring gearwheel, The gear support structure characterized by the above-mentioned. The gear support structure according to claim 1,
The ring gear includes outer peripheral teeth formed on the outer peripheral side of the ring and inner peripheral teeth formed on the inner peripheral side, the drive gear meshes with the outer peripheral teeth, the output gear meshes with the inner peripheral teeth, and the rolling gear. A moving body supports the ring gear in contact with a tip of an inner peripheral tooth of the ring gear. The gear support structure according to claim 1,
The gear support structure, wherein the rolling element is rotatably attached to the output shaft via a bearing. The gear support structure according to claim 1,
A gear support structure, wherein the rolling element has a lower hardness than a ring gear. Ring gear,
A drive gear that meshes with the ring gear and rotationally drives the ring gear;
A plurality of output gears that mesh with the ring gear and respectively drive the plurality of output shafts;
A casing that houses the ring gear, the drive gear, and the output gear;
An arcuate support member attached to the casing;
The arcuate support member supports the ring gear in a radial direction by contacting an arcuate support portion formed on the member with a tip of an inner peripheral tooth formed on the inner peripheral side of the ring gear. A gear support structure characterized in that a convex portion formed on an arc-shaped support portion abuts against a side surface of the ring gear to support the ring gear in the axial direction. Ring gear,
A drive gear that meshes with the ring gear and rotationally drives the ring gear;
A plurality of output gears that mesh with the ring gear and respectively drive the plurality of output shafts;
A casing that houses the ring gear, the drive gear, and the output gear;
Comprising a vane attached to the output shaft;
In the gear support structure of the centrifugal compressor that adjusts the flow rate of the gas supplied to the centrifugal compressor by the rotation of the vane that rotates in conjunction with the rotation of the drive gear,
A rolling element disposed on a side surface of the output gear so as to be rotatable with respect to the output shaft;
The rolling element includes a portion in contact with a part of the ring gear, and supports the ring gear through the portion.

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