JP2013199999A - Reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact reduction gear which has a large speed reduction ratio and can smoothly change rotation directions with low noise.SOLUTION: A reduction gear includes a reversing mechanism 4 and a planetary mechanism 5 disposed axially adjoining to each other between an input shaft 1 and a rotary ring 3. When the input shaft 1 rotates, revolution of a planetary gear 16 is transmitted to an output shaft 2, while the rotary ring 3 is rotated in a reverse direction by the reversing mechanism 4. A traction drive system is employed as the reversing mechanism 4, in which balls 14 which come in rolling contact with both of the outer circumferential surface of the input shaft 1 and the inner circumferential surface of the rotary ring 3 indirectly, rotate while the revolution around the input shaft 1 is restricted, and change the rotation of the input shaft 1 into the opposite direction to transmit to the rotary ring. The reduction gear can be made compact, obtains a large reduction ratio, uses the reduced number of gears compared to a reduction gear having two planetary gear mechanisms, and can smoothly change rotation directions with low noise.

Description

  The present invention relates to a speed reducer that decelerates rotation of an input shaft by a planetary mechanism and transmits it to an output shaft.

  In office machines such as printers, copiers, and facsimile machines, a small motor that rotates at high speed is generally used to reduce the size of the drive unit. Therefore, as a speed reducer built between the motor and the driven unit, A compact and large reduction ratio is required.

  On the other hand, in Patent Document 1, an input shaft, an output shaft, a rotating ring (annular frame) disposed radially outside the input shaft, and the input shaft and the rotating ring are adjacent to each other in the axial direction. A first planetary gear mechanism provided so as to have a first support shaft that rotatably supports the planetary gear (first planetary gear) of the first planetary gear mechanism, and is fixed to the output shaft. A second support shaft that supports the planetary gear (second planetary gear) of the second planetary gear mechanism so as to be able to rotate and is fixed to a stationary member (stationary wall), and when the input shaft rotates, 2. Description of the Related Art A reduction gear (complex planetary gear mechanism) has been proposed in which a rotating ring is rotated in a direction opposite to an input shaft by rotation of two planetary gears, and a revolution of the first planetary gear is transmitted to an output shaft through a carrier. .

  According to this configuration, the revolution of the first planetary gear is partially offset by the reverse rotation of the rotating ring, and the rotation of the output shaft is slowed accordingly, so that a single planetary gear mechanism is disposed between the input shaft and the fixed ring. Compared with the general speed reducer provided in, a very large reduction ratio can be obtained. In addition, since the two planetary gear mechanisms are provided so as to be adjacent to each other in the axial direction, the radial dimension is not changed from that of a general reduction gear, and the axial dimension is slightly increased, so that compactness can be secured. .

JP 2008-275112 A

  By the way, although the reduction gear described in the above-mentioned patent document 1 is compact and can obtain a large reduction ratio as described above, since it has two planetary gear mechanisms, it is a general one that has only one planetary gear mechanism. The number of gears is larger than that of a simple reduction gear, and noise is increased, which may make it difficult to employ a device that requires quietness, such as an office machine. There is also a problem that when the rotation direction of the input shaft is switched, a delay in rotation transmission to the output shaft due to backlash between gears meshing with each other increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a speed reducer that is compact, has a large reduction gear ratio, is low in noise, and can smoothly switch the rotation direction.

  In order to solve the above-described problems, the present invention provides an input shaft, an output shaft, a rotating ring disposed radially outside the input shaft, and the rotating ring provided between the input shaft and the rotating ring. And a reversing mechanism that rotates in a direction opposite to the input shaft, and is provided between the input shaft and the rotating ring so as to be adjacent to the reversing mechanism in the axial direction. A planetary mechanism having a plurality of planetary members revolving around the input shaft, a carrier having a support shaft that is passed through the central portion of the planetary member and supports the planetary member so as to rotate, and is fixed to the output shaft; A reduction gear that transmits the revolution of the planetary member when the input shaft rotates to the output shaft via a carrier, and the reversing mechanism includes both the outer peripheral surface of the input shaft and the inner peripheral surface of the rotating ring. A rotation transmission member that makes rolling contact with By rotating in a condition in which the rotation transmitting member is constrained to revolve around the input shaft, than it was adopted as to transmit the rotating ring by changing the rotation of the input shaft in the opposite direction.

  According to the above configuration, as in the reducer provided with the two planetary gear mechanisms described above, the revolution of the planetary member is partially offset by the reverse rotation of the rotating ring to obtain a large reduction ratio, and the reversing mechanism and the planetary gear Since the mechanisms are provided so as to be adjacent to each other in the axial direction, compactness can be secured. Moreover, since the reversing mechanism is a traction drive system that uses a rotation transmission member that is in rolling contact with both the outer peripheral surface of the input shaft and the inner peripheral surface of the rotating ring, the number of gears is smaller than that of a speed reducer having two planetary gear mechanisms. Therefore, the rotation direction can be switched smoothly with low noise.

  Specifically, the reversing mechanism is arranged between an inner ring fitted and fixed to the outer circumference of the input shaft, an outer ring fitted and fixed to the inner circumference of the rotating ring, and the inner ring and the outer ring. A plurality of rolling elements and a cage that holds the rolling elements in a rollable manner, and a gap between the rolling elements and the inner and outer rings (hereinafter also referred to as “bearing internal gap”). In addition, by fixing the retainer to a stationary member, it is possible to employ the rolling element as the rotation transmission member. Here, the bearing structure of the reversing mechanism is assembled in a state having the bearing internal clearance, and if the bearing internal clearance is eliminated when the bearing structure is assembled, the assembly work of the bearing structure is facilitated. It is possible to make it difficult for parts to be damaged during work.

  As another specific configuration of the reversing mechanism, a plurality of fixed shafts fixed to a stationary member are inserted between the input shaft and the rotating ring in parallel with the input shaft, and can rotate on each of the fixed shafts. It is also possible to employ a rotating roller that is supported by the rotation transmission member.

  On the other hand, as a specific configuration of the planetary mechanism, a planetary gear that is provided with a sun gear on the outer peripheral surface of the input shaft, an internal gear on the inner peripheral surface of the rotating ring, and meshes with both the sun gear and the internal gear. As a planetary member, or a planetary roller that is in rolling contact with both the outer peripheral surface of the input shaft and the inner peripheral surface of the rotating ring and is rotatably supported by the support shaft. Can be adopted.

  In addition, if one end of the input shaft is fitted into an engagement hole provided on one end surface of the output shaft so as to be relatively rotatable, the input shaft and the output shaft are prevented from being bent and the rotation thereof is smoother. Can be.

  In the speed reducer according to the present invention, as described above, the reversing mechanism and the planetary mechanism that change the rotation of the input shaft in the reverse direction and transmit the rotation to the rotating ring are adjacent to each other in the axial direction between the input shaft and the rotating ring. A carrier having a support shaft that rotatably supports the planetary member of the planetary mechanism is fixed to the output shaft, and the reversing mechanism rotates in contact with both the outer peripheral surface of the input shaft and the inner peripheral surface of the rotating ring. Because it is a traction drive system that uses a transmission member, it is compact and provides a large reduction ratio, and it has fewer gears than those with two planetary gear mechanisms, and it can be switched smoothly with low noise. Can be done.

Longitudinal front view of the speed reducer of the first embodiment 1 is an exploded perspective view of FIG. Sectional view along line III-III in FIG. Sectional view along line IV-IV in FIG. Longitudinal front view of the reducer according to the second embodiment Sectional view along line VI-VI in FIG. Longitudinal front view of the reducer according to the third embodiment 7 is an exploded perspective view of the main part of FIG. Sectional view along line IX-IX in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 show a first embodiment. As shown in FIGS. 1 and 2, the speed reducer of this embodiment includes an input shaft 1 and an output shaft 2 arranged on the same axis, and a rotating ring 3 arranged on the radially outer side of the input shaft 1. A reversing mechanism 4 and a planetary mechanism 5 provided so as to be adjacent to each other in the axial direction between the input shaft 1 and the rotating ring 3, and a carrier 6 having a plurality of support shafts 6 a engaged with the planetary mechanism 5 on one side surface. An outer cylinder 7 having a lid portion 7a that covers the outer peripheral surfaces of the rotating ring 3 and the carrier 6 and allows the output shaft 2 to pass therethrough, and a disk-shaped lid 8 that closes the open end of the outer cylinder 7 while allowing the input shaft 1 to pass through. It is basically composed of. The inner peripheral surface of the lid 8 and the inner peripheral surface of the lid portion 7a of the outer cylinder 7 are radial bearing surfaces that rotatably support the input shaft 1 and the output shaft 2, respectively. The lid 8 is fixed to the outer cylinder 7 with a bolt (not shown) screwed in the axial direction.

  In the input shaft 1 and the output shaft 2, the distal end side portion of the input shaft one end portion 1a formed in a small diameter is in an engagement hole 2b provided in the center of the end surface of the output shaft one end portion 2a formed in a large diameter. The input / output shafts 1 and 2 are prevented from being deformed flexibly so as to rotate smoothly. Further, the input shaft 1 is provided with a sun gear 9 that constitutes a part of the planetary mechanism 5 on the outer peripheral surface of the central side portion of the one end 1a. On the other hand, the output shaft 2 is rotatably supported by the lid portion 7a of the outer cylinder 7 at the center portion of the one end portion 2a, and the carrier 6 is integrally formed at the tip end portion of the one end portion 2a. The other end portions of the input / output shafts 1 and 2 are formed with flat portions 1b and 2c on the outer peripheral surfaces, respectively, and are opposed to engagement holes having a D-shaped cross section of the input side rotation member and the output side rotation member which are not shown It is designed to be non-rotatable.

  The rotating ring 3 is fitted and fixed to a spacer 10 constituting a part of the reversing mechanism 4 on one end side (input side) of the inner periphery, and the planetary side is connected to the other end side (output side) of the inner peripheral surface. An internal gear 11 constituting a part of the mechanism 5 is provided. The spacer 10 may be formed integrally with the rotating ring 3 or may be provided between the input shaft 1 and the inner ring 12.

  As shown in FIGS. 1 and 3, the reversing mechanism 4 includes an inner ring 12 that is fitted and fixed to the outer periphery of the input shaft 1, and an outer ring 13 that is fitted and fixed to the inner periphery of the rotating ring 3 via a spacer 10. And a bearing structure including a plurality of balls (rolling elements) 14 disposed between the inner ring 12 and the outer ring 13 and a retainer 15 that holds the balls 14 in a rollable manner. Then, a clearance (bearing internal clearance) between the ball 14 and the inner ring 12 and the outer ring 13 is eliminated, and the ball 14 is brought into rolling contact with the inner ring 12 and the outer ring 13 so that traction is generated between the ball 14 and the inner and outer rings 12 and 13. In addition, a plurality of protrusions 15a protruding from one end surface of the cage 15 are fitted into the attachment holes 8a provided in the lid 8, respectively, so that the cage 15 is fixed to the lid 8 as a stationary member. Thereby, when the input shaft 1 rotates integrally with the inner ring 12, the ball 14 to which the rotation of the input shaft 1 is transmitted via the inner ring 12 is restrained from revolving around the input shaft 1 by the cage 15. The rotation ring 3 is rotated in the direction opposite to the input shaft 1 integrally with the outer ring 13 and the spacer 10.

  Here, the bearing structure of the reversing mechanism 4 is assembled in advance with a bearing internal clearance. When this bearing structure is incorporated into a reduction gear, for example, the inner ring 12 and the outer ring 13 are pressed into the input shaft 1 and the spacer 10 to be deformed in the radial direction so that the bearing internal clearance is eliminated. As a result, the assembly work of the bearing structure is facilitated, and it is difficult for parts to be damaged during the work.

  As shown in FIGS. 1 and 4, the planetary mechanism 5 includes a sun gear 9 provided on the outer peripheral surface of the input shaft one end 1 a and an internal gear 11 provided on the inner peripheral surface of the rotating ring 3. A planetary gear 16 as a plurality of planetary gears meshed with both the sun gear 9 and the internal gear 11, and a ball provided between the support shaft 6 a of the carrier 6 passed through the center of the planetary gear 16 and the planetary gear 16. And a bearing 17. The planetary gear 16 is formed integrally with an outer ring of a ball bearing 17, and is supported on the support shaft 6 a of the carrier 6 via the ball bearing 17 so as to be capable of rotating. When the input shaft 1 rotates, the planetary gear 16 rotates around the input shaft 1 in the same direction as the input shaft 1 while rotating by meshing with the sun gear 9 of the input shaft 1 and the internal gear 11 of the rotating ring 3. Revolve.

  This speed reducer has the above-described configuration. When the input shaft 1 rotates, the reversing mechanism 4 rotates the rotating ring 3 in the direction opposite to the input shaft 1 and rotates the planetary gear 16 of the planetary mechanism 5 while rotating. The revolution of the planetary gear 16 is transmitted to the output shaft 2 through the carrier 6 by revolving in the same direction as the shaft 1. Accordingly, the revolution of the planetary gear 16 is partially offset by the reverse rotation of the rotating ring 3 to obtain a large reduction ratio, and the reversing mechanism 4 and the planetary mechanism 5 are provided so as to be adjacent to each other in the axial direction. Can also be secured. The reduction ratio and the rotation direction of the output shaft 2 (revolution direction of the planetary gear 16) are the outer diameter of the inner ring 12 of the reversing mechanism 4, the inner diameter of the outer ring 13, the diameter of the ball 14, and the sun gear 9 of the planetary mechanism 5. It can be changed by appropriately setting the PCD dimensions and the number of teeth of the gear 11 and the planetary gear 16.

  Moreover, the reversing mechanism 4 transmits the ball 14 that is in rolling contact with both the outer peripheral surface of the input shaft 1 and the inner peripheral surface of the rotating ring 3 to the rotating ring 3 by changing the rotation of the input shaft 1 in the reverse direction. Since the traction drive system used as the rotation transmission member is used, the number of gears is smaller than that of a reduction gear having two planetary gear mechanisms, and the total backlash between gears meshing with each other is also reduced. Therefore, the noise is low, and it is suitable for incorporation into a device such as an office machine that requires quietness, and the rotation transmission delay to the output shaft is small when the rotation direction of the input shaft is switched. Further, there is an advantage that there is no design restriction as in the case where two planetary gear mechanisms are incorporated in parallel, and the degree of freedom in design is great.

  5 and 6 show a second embodiment. In this embodiment, based on the first embodiment, the sun gear 9 on the outer peripheral surface of the input shaft one end portion 1 a and the internal gear 11 on the inner peripheral surface of the rotating ring 3 are eliminated, and a planetary roller 18 is used instead of the planetary gear 16. This is a planetary member of the planetary mechanism 5. Since the other configuration and rotation transmission operation are the same as those of the first embodiment, the same components as those of the first embodiment are basically denoted by the same reference numerals and description thereof is omitted. The same applies to a third embodiment described later.

  As with the planetary gear 16 of the first embodiment, the planetary roller 18 is integrally formed with an outer ring of a ball bearing 17 and is supported on the support shaft 6 a of the carrier 6 via the ball bearing 17 so as to be capable of rotating. And it is in rolling contact with both the outer peripheral surface of the input shaft one end 1a and the inner peripheral surface of the rotating ring 3, and when the input shaft 1 rotates, it revolves around the input shaft 1 while rotating by traction. .

  In the second embodiment, in addition to the reversing mechanism 4, the planetary mechanism 5 also uses a traction drive system and eliminates the gear incorporated in the speed reducer. Therefore, compared to the first embodiment, the rotational direction can be switched with lower noise. It can be done smoothly.

In the first and second embodiments described above, the balls 14 are used as the rolling elements constituting the bearing structure of the reversing mechanism 4, but this may be replaced with a roller. In addition, the inner ring of the bearing structure is formed integrally with the input shaft, or the outer ring is formed integrally with the rotating ring together with the spacer so that the balls and rollers that are rolling elements are in direct contact with the input shaft and rotating ring. May be.

  7 to 9 show a third embodiment. This embodiment is based on the second embodiment and the bearing structure of the reversing mechanism 4 is changed.

  In the reversing mechanism 4 of the third embodiment, between the input shaft 1 and the rotating ring 3, a plurality of fixed shafts 19 having one end fitted and fixed in the mounting hole 8 a of the lid 8 are inserted in parallel with the input shaft 1. Then, the rotation roller 21 supported rotatably on each fixed shaft 19 via the ball bearing 20 is brought into direct contact with both the outer peripheral surface of the input shaft 1 and the inner peripheral surface of the rotating ring 3, Traction is generated between the rotating roller 21 and the input shaft 1 and the rotating ring 3. As a result, the rotation roller 21 is a rotation transmission member that rotates in a state in which the revolution around the input shaft 1 is restricted during one rotation of the input shaft, and changes the rotation of the input shaft 1 in the reverse direction and transmits the rotation to the rotation ring 3. ing.

  The rotation roller 21 is formed integrally with the outer ring of the ball bearing 20. Further, bearings are provided between the lid 8 and the input shaft 1, between the lid portion 7 a of the outer cylinder 7 and the output shaft 2, and between the input shaft one end portion 1 a and the engagement hole 2 b of the output shaft one end portion 2 a. The input shaft 1 is formed with the same diameter over the entire length, the spacer 10 of the reversing mechanism 4 is formed integrally with the rotating ring 3, and the support shaft 6a of the carrier 6 is formed separately. This is different from the first and second embodiments.

  In the third embodiment, as in the second embodiment, the reversing mechanism 4 and the planetary mechanism 5 are both of the traction drive type, so that the switching of the rotation direction is smoother with lower noise than in the first embodiment.

DESCRIPTION OF SYMBOLS 1 Input shaft 1a One end part 2 Output shaft 2a One end part 2b Engagement hole 3 Rotating ring 4 Reversing mechanism 5 Planetary mechanism 6 Carrier 6a Support shaft 7 Outer cylinder 8 Lid (stationary member)
9 Sun gear 10 Spacer 11 Internal gear 12 Inner ring 13 Outer ring 14 Ball (rolling element)
15 Cage 16 Planetary Gear 17 Ball Bearing 18 Planetary Roller 19 Fixed Shaft 20 Ball Bearing 21 Rotating Roller

Claims (7)

  An input shaft, an output shaft, a rotating ring disposed radially outside the input shaft, a reversing mechanism provided between the input shaft and the rotating ring, and rotating the rotating ring in a direction opposite to the input shaft; A plurality of planetary members provided between the input shaft and the rotating ring so as to be adjacent to the reversing mechanism in the axial direction and revolving around the input shaft while being engaged with the input shaft and the rotating ring and rotating. A planetary mechanism having a planetary mechanism, a support shaft that is passed through the center of the planetary member and supports the planetary member so as to be able to rotate, and is fixed to the output shaft, and the planetary shaft when the input shaft rotates In the speed reducer that transmits the revolution of the member to the output shaft through the carrier, the reversing mechanism has a rotation transmitting member that is in rolling contact with both the outer peripheral surface of the input shaft and the inner peripheral surface of the rotating ring. The transmission member rotates around the input shaft. Reduction gear, characterized in that by rotating a bundle state, is to transmit the rotating ring by changing the rotation of the input shaft in the opposite direction.   An inner ring fitted and fixed to the outer periphery of the input shaft; an outer ring fitted and fixed to the inner periphery of the rotating ring; and a plurality of rolling elements disposed between the inner ring and the outer ring. And a bearing structure configured to hold the rolling element so that the rolling element can roll, eliminating a gap between the rolling element, the inner ring, and the outer ring, and fixing the cage to a stationary member. The speed reducer according to claim 1, wherein a moving body is the rotation transmission member.   A bearing structure of the reversing mechanism is assembled with a gap between the rolling element and an inner ring and an outer ring, and the gap between the rolling element and the inner ring and the outer ring is eliminated when the bearing structure is incorporated. The speed reducer according to claim 2.   The reversing mechanism inserts a plurality of fixed shafts fixed to a stationary member between the input shaft and the rotating ring in parallel to the input shafts, and rotates the rotation rollers supported on these fixed shafts so as to be able to rotate. The speed reducer according to claim 1, wherein the speed reducer is a rotation transmission member.   In the planetary mechanism, a sun gear is provided on the outer peripheral surface of the input shaft, an internal gear is provided on the inner peripheral surface of the rotating ring, and a planetary gear meshing with both the sun gear and the internal gear is used as the planetary member. The speed reducer according to claim 1, wherein the speed reducer is provided.   The planetary mechanism is characterized in that a planetary roller which is in rolling contact with both the outer peripheral surface of the input shaft and the inner peripheral surface of the rotating ring and is supported so as to be able to rotate on the support shaft is the planetary member. The speed reducer according to any one of claims 1 to 4.   The speed reducer according to any one of claims 1 to 6, wherein one end portion of the input shaft is fitted into an engagement hole provided on one end surface of the output shaft so as to be relatively rotatable.

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