JP2014062590A - Speed reducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed reducer having high speed reduction ratio and capable of smoothly changing a rotating direction with low noise.SOLUTION: A plurality of intermediate shafts 6a extended in the radial direction of an input shaft 1, are disposed between an input ring 3 fitted and fixed to an outer periphery of the input shaft 1, and a control ring 4 to which the input shaft 1 is rotatably inserted. Elements 7 respectively rotatably mounted on outer peripheries of the intermediate shafts 6a are rotated while kept into contact with the input ring 3 and the control ring 4. The control ring 4 is rotated in a reverse direction with respect to the input shaft 1 by a reversing mechanism 5 when the input shaft 1 is rotated. Each of the elements 7 revolves around the input shaft 1 integrally with the intermediate shaft 6a while rotating by the difference in rotational frequencies of the input ring 3 and the control ring 4, and the revolution is transmitted to the output shaft 2 through the intermediate shafts 6a. Thus, high speed reduction ratio can be achieved, and the rotating direction can be smoothly changed with low noise by applying a traction drive system in transmitting the rotation.

Description

  The present invention relates to a speed reducer that decelerates rotation of an input shaft 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, What has a large reduction ratio, low noise and no delay in rotation transmission is required.

  On the other hand, in Patent Document 1, bevel gears are provided to be opposed to two input shafts that are driven to rotate in the opposite directions on the same axis, and the shafts orthogonal to the input shaft are disposed on these two opposed bevel gears. By rotating the pinion bevel gear rotating around, causing the pinion bevel gear to revolve around the input shaft by the difference in the number of rotations of the two input shafts, and transmitting the revolution of this pinion bevel gear to the output shaft, A differential bevel gear reduction mechanism has been proposed that can provide a large reduction ratio.

JP 2006-162020 A

  However, since the speed reduction mechanism described in Patent Document 1 uses a gear for its rotation transmission, noise due to the meshing of the gear is likely to increase, and it is particularly adopted for a device that requires quietness such as an office machine. Hateful. 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 tends to increase.

  Accordingly, an object of the present invention is to provide a reduction gear having a large reduction ratio, low noise, and capable of smoothly switching the rotation direction.

  In order to solve the above problems, a reduction gear according to the present invention includes an input shaft, an output shaft, an input wheel fitted and fixed to the outer periphery of the input shaft, and a control wheel through which the input shaft is rotatably inserted. A plurality of intermediate shafts extending in the radial direction of the input shaft at axial positions between the input wheel and the control wheel, and rotatably mounted on the outer periphery of each of the intermediate shafts at positions facing each other across the intermediate shaft. Rolling contact with the input wheel and the control wheel, and when the input shaft rotates, the input shaft is integrated with the intermediate shaft while the tops rotate due to the difference in rotation speed between the input wheel and the control wheel. The revolution is transmitted to the output shaft through the intermediate shaft.

  That is, by utilizing the differential rotation of the input wheel and the control wheel, revolving around the input shaft while rotating the top provided between the two wheels, and transmitting the revolution to the output shaft, the above-mentioned difference is achieved. As with the bevel gear reduction mechanism, a large reduction ratio can be obtained, and the rotation transmission between the top and the input wheel and the control wheel is a traction drive system. The direction can be changed smoothly.

  Here, the control wheel may rotate in a direction opposite to the input shaft when the input shaft rotates. In that case, it is preferable to provide a reversing mechanism for changing the rotation of the input shaft in the reverse direction and transmitting it to the control wheel between the input shaft and the control wheel. As a specific configuration of the reversing mechanism, there is provided a rolling element that rolls in contact with both the outer peripheral surface of the input shaft and the inner peripheral surface of the control wheel, and rotates in a state where the revolution around the input shaft is restricted. Can be used.

  Alternatively, the control wheel can be fixed. In this case, the rotational speed of the output shaft is limited to ½ of the rotational speed of the input shaft, but the overall structure of the speed reducer is simplified.

  The top is pressed against the input wheel and the control wheel by a pressing member attached to the intermediate shaft, so that traction can be reliably generated between the input wheel and the control wheel. By arranging them at equal intervals in the circumferential direction, traction can be effectively loaded.

  The output shaft is preferably disposed on the same axis as the input shaft.

  As described above, the speed reducer of the present invention revolves around the input shaft while rotating the top provided between the two wheels by the differential rotation of the input wheel and the control wheel, and transmits the revolution to the output shaft. Because the rotation transmission between the roller and the input wheel and the control wheel is a traction drive system, a large reduction ratio can be obtained and the rotation direction can be reduced with less noise compared to a gear that transmits rotation using gears. Can be switched smoothly.

Longitudinal front view of the speed reducer of the first embodiment Sectional view along the line II-II in FIG. Sectional view along line III-III in FIG. Longitudinal front view of the reducer according to the second embodiment

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show a first embodiment. As shown in FIG. 1, the speed reducer of this embodiment includes an input shaft 1 and an output shaft 2 arranged on the same axis, an input wheel 3 fitted and fixed to the outer periphery of the input shaft 1, and one end. The outer ring portion 4a has a boss portion 4b at the other end, and the control wheel 4 through which the input shaft 1 is rotatably inserted, and the reversing mechanism 5 that transmits the rotation of the input shaft 1 to the control wheel 4 in the reverse direction. And a rotation transmission member 6 having two intermediate shafts 6a extending in the radial direction of the input shaft 1 at an axial position between the input wheel 3 and the control wheel 4, and rotatably attached to the outer periphery of each intermediate shaft 6a. The input wheel 3 and the rolling contact 7 are basically constituted by a rolling contact 7 at a position facing each other across the intermediate shaft 6a.

  As shown in FIGS. 1 and 2, the reversing mechanism 5 includes a control input wheel 8 that is fitted and fixed to the outer periphery of the input shaft 1, and a plurality of reversing mechanisms 5 disposed between the control input wheel 8 and the control wheel 4. A roller 9 as a rolling element, two rows of bearings 10 that rotatably support one end of each roller 9, and a stationary member 11 having a recess 11 a into which each bearing 10 is fitted, and through which the input shaft 1 is inserted. Consists of. The other end of each roller 9 is brought into rolling contact with both the outer peripheral surface of the control input wheel 8 and the inner peripheral surface of the outer ring portion 4a of the control wheel 4, so that the roller 9, the control input wheel 8, and the control wheel 4 Traction is generated between the two. Thereby, when the input shaft 1 rotates integrally with the control input wheel 8, the roller 9 to which the rotation of the input shaft 1 is transmitted via the control input wheel 8 is transferred to the stationary member 11 via the bearing 10. The control wheel 4 rotates in a direction opposite to that of the input shaft 1 at a different rotational speed by rotating around one revolution while being constrained.

  The input wheel 3 and the control input wheel 8 are fixed to the input shaft 1 by fitting a pin 12 penetrating the input shaft 1 in the radial direction into a recess formed on the other end surface of the input wheel 3 and the control input wheel 8. I am letting. It is also possible to form the input wheel or the control input wheel integrally with the input shaft, and to directly contact the outer peripheral surface of the input shaft with the top or roller. On the other hand, the output shaft 2, the control wheel 4, and the stationary member 11 are incorporated in a state where the input shaft 1 is rotatably inserted through the bearings 13. The output shaft 2 and the stationary member 11 are prevented from coming off by a retaining ring 14 fitted in an annular groove on the outer periphery of both ends of the input shaft 1.

  As shown in FIGS. 1 and 3, the rotation transmission member 6 includes the two intermediate shafts 6 a and the two rotation transmission shafts 6 b extending in the radial direction of the input shaft 1 on the outer periphery of the input shaft 1. The cylindrical portion 6c that is rotatably fitted is protruded alternately at 90 ° intervals in the circumferential direction.

  The intermediate shaft 6a of the rotation transmitting member 6 has the top 7 rotatably attached to the outer periphery via a bearing 15, and a nut 16 as a pressing member is screwed to the tip. By tightening the nut 16, the top 7 pressed by the nut 16 via the bearing 15 causes the rolling contact surface 7 a formed on the outer peripheral portion of the input shaft 1 center side end surface to be changed to the outer periphery of the input wheel 3. It is pressed against the outer peripheral surface of the surface and the boss portion 4 b of the control wheel 4 so that traction is reliably generated between the input wheel 3 and the control wheel 4. Here, since the two tops 7 are arranged so as to face each other with the center of the input shaft 1 interposed therebetween, the traction can be effectively loaded. Although the number of intermediate shafts and tops can be increased, in that case as well, in order to effectively load traction, it is desirable to arrange them at equal intervals in the circumferential direction of the input shaft.

  On the other hand, each rotation transmission shaft 6b is fitted into a notch 2b of an annular engagement portion 2a projecting from the outer peripheral portion of one end surface of the output shaft 2, and the rotation transmission member 6 rotates around the input shaft 1. Is transmitted to the output shaft 2. The engaging portion 2 a of the output shaft 2 is also provided with a notch 2 c for avoiding interference with the intermediate shaft 6 a and the nut 16.

  The speed reducer has the above-described configuration. When the input shaft 1 rotates, the reversing mechanism 5 rotates the control wheel 4 at a different rotational speed in the opposite direction to the input shaft 1 and rotates integrally with the input shaft 1. Due to the difference in the rotational speed between the input wheel 3 and the control wheel 4, the input wheel 3 and the control wheel 4 are revolved in the same direction as the input shaft 1 while rotating, and the revolution is intermediate between the rotation transmission member 6. The output is transmitted to the output shaft 2 via the shaft 6a and the rotation transmission shaft 6b.

  Therefore, a large reduction ratio can be obtained by utilizing the differential rotation of the input wheel 3 and the control wheel 4. The reduction ratio is determined based on the outer diameter of the control input wheel 8 of the reversing mechanism 5, the inner diameter of the control wheel outer ring portion 4a, the diameter of the roller 9, and the outer diameters of the input wheel 3 and the control wheel boss portion 4b having the same dimensions. It can be changed by appropriately setting.

  In addition, since the rotation transmission is a traction drive system including the reversing mechanism 5 and no gear is used, the noise at the time of gear meshing, such as those having a conventional bevel gear mechanism, and between the gears meshing with each other There is no backlash. 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 2 when the rotation direction of the input shaft 1 is switched is small.

  In addition, since all the forces that generate traction for rotation transmission act in the radial direction, there is no possibility that a thrust force is generated by these forces, and there is an advantage that the structure can be simplified.

  In the above-described embodiment, the rolling element of the reversing mechanism 5 that rotates while being constrained to revolve around the input shaft 1 is the roller 9 that is rotatably supported by the bearing 10. A ball or the like that is rotatably held by a fixed cage may also be used.

  FIG. 4 shows a second embodiment. In this embodiment, the reversing mechanism 5 of the first embodiment is eliminated, and the control wheel 4 without the outer ring portion 4a at one end is fixed to a stationary member (not shown). The configuration of the other parts is the same as in the first embodiment.

  In the second embodiment, the rotational speed of the output shaft 2 is limited to 1/2 of the rotational speed of the input shaft 1 (the reduction ratio is 2), but the overall structure of the speed reducer is simpler than that of the first embodiment. Become.

DESCRIPTION OF SYMBOLS 1 Input shaft 2 Output shaft 2a Engagement part 2b, 2c Notch 3 Input wheel 4 Control wheel 4a Outer ring part 4b Boss part 5 Reversing mechanism 6 Rotation transmission member 6a Intermediate shaft 6b Rotation transmission shaft 6c Tube part 7 Top 7a Rolling contact Surface 8 Control input wheel 9 Roller (rolling element)
11 Stationary member 16 Nut (pressing member)

Claims (8)

  An input shaft, an output shaft, an input wheel fitted and fixed to the outer periphery of the input shaft, a control wheel through which the input shaft is rotatably inserted, and an axial position between the input wheel and the control wheel A plurality of intermediate shafts extending in the radial direction of the input shaft, and rotatably attached to the outer periphery of each of the intermediate shafts, and rolling contact with the input wheel and the control wheel at positions facing each other across the intermediate shaft, When the input shaft rotates, due to the difference in rotation speed between the input wheel and the control wheel, the tops rotate around the input shaft together with the intermediate shaft while rotating, and the revolution is output via the intermediate shaft. Reducer that transmits to the shaft.   The speed reducer according to claim 1, wherein the control wheel rotates in a direction opposite to the input shaft when the input shaft rotates. The speed reducer according to claim 2, wherein a reversing mechanism is provided between the input shaft and the control wheel to transmit the rotation of the input shaft to the control wheel by changing the rotation of the input shaft in the reverse direction.   The reversing mechanism is provided with a rolling element that is in rolling contact with both the outer peripheral surface of the input shaft and the inner peripheral surface of the control wheel and that rotates in a state in which revolving around the input shaft is constrained. The speed reducer according to claim 3.   The speed reducer according to claim 1, wherein the control wheel is fixed.   The speed reducer according to any one of claims 1 to 5, wherein the top is pressed against the input wheel and the control wheel by a pressing member attached to the intermediate shaft.   The speed reducer according to any one of claims 1 to 6, wherein the tops are arranged at equal intervals in the circumferential direction of the input shaft.   The speed reducer according to any one of claims 1 to 7, wherein the output shaft is arranged on the same axis as the input shaft.

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