JP2009150416A - Cycloid reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cycloid reduction gear capable of avoiding an operation lock while suppressing a backlash between a transmission pin and a transmission hole to the necessary minimum. <P>SOLUTION: The cycloid reduction gear comprises a deceleration driving member 7 which decelerates and rotates while revolving around an axle line A1 of an input shaft 2, a driven member 9 which is integrated with an output shaft 3 arranged coaxially with the output shaft 2 and a joint 10 which couples both members 7, 9. The joint 10 consists of a plurality of transmission holes 11 provided to the deceleration driving member 7 so as to be arranged on a pitch circle C2 with an axial line A2 of the deceleration driving member 7 as a center and a transmission pin 12 provided to the driven member 9 so as to be arranged on a pitch circle C3 with an axial line A1 of the output shaft 3 as a center and loosely fitted to the transmission hole 11. A notch-shaped escape parts 11b for preventing the interference with the driven pin 12 is provided to both parts in the inner surface of the transmission hole 11 which face each other on a radial line r of the pitch circle C2 of the transmission hole 11 group which passes through the center c of the transmission hole 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is integrally connected to a speed reduction drive member that revolves around the axis of the input shaft along with the rotation of the input shaft and is forced to decelerate and rotate, and an output shaft that is arranged with the input shaft aligned with the axis. And a joint provided between the speed reduction drive member and the driven member and transmitting the rotation of the speed reduction drive member to the driven member, the joint having a first pitch centered on the axis of the speed reduction drive member A plurality of first transmission portions provided on the speed reduction drive member so as to be arranged at equal intervals on the circle, and a plurality of provided on the driven member so as to be arranged at equal intervals on a second pitch circle centered on the axis of the output shaft. The present invention relates to an improvement of a cycloid reduction gear that includes a second transmission portion, and one of the first and second transmission portions is a transmission hole, and the other is a transmission pin that is loosely fitted into the transmission hole.

Such a cycloid reducer is already known as disclosed in Patent Document 1 below.
JP 2006-258289 A

  In such a cycloid reducer, as the input shaft rotates, the speed reduction drive member revolves around the axis of the input shaft and is forced to decelerate, and only that rotation is transmitted to the driven member via the joint member. Therefore, the transmission hole is formed to have a diameter larger than that of the transmission pin, and a clearance that allows the revolution of the speed reduction drive member is secured. That is, when the transmission hole is too small, the transmission pin causes an operation lock on a part of the inner surface of the transmission hole, thereby inhibiting the revolution of the speed reduction drive member. Therefore, in the prior art, the transmission hole is formed with a sufficiently larger diameter than the transmission pin in consideration of manufacturing errors.

  However, in such a case, the backlash between the transmission pin and the transmission hole becomes larger than necessary. Therefore, when the rotation of the deceleration drive member is reversed, the operating noise accompanying the backlash and the reverse response of the output shaft It will cause a decline.

  The present invention has been made in view of such circumstances, and it is intended to provide a cycloid reducer that can avoid operation lock while minimizing backlash between the transmission pin and the transmission hole. Objective.

  In order to achieve the above object, the present invention is arranged such that a speed reduction driving member that revolves around the axis of the input shaft along with the rotation of the input shaft is forced to decelerate and rotate, and the input shaft and the axis are aligned. A driven member integrally connected to the output shaft, and a joint provided between the speed reduction driving member and the driven member, and transmitting the rotation of the speed reduction driving member to the driven member. A plurality of first transmission parts provided in the speed reduction drive member so as to be arranged at equal intervals on a first pitch circle centered on the axis, and arranged at equal intervals on a second pitch circle centered on the axis of the output shaft In the cycloid reducer, the transmission pin is constituted by a second transmission portion provided on the driven member, and one of the first and second transmission portions is a transmission hole, and the other is a transmission pin loosely fitted in the transmission hole. The cross-sectional shape is On the inner surface of the transmission hole, a notch-shaped relief that prevents interference with the transmission pin is formed on the inner surface of the transmission hole that passes through the center of the transmission hole and is opposed to the radial line of the pitch circle of the transmission hole group. The first feature is that the portion is provided.

  According to the present invention, in addition to the first feature, the transmission hole includes a pair of arcuate transmission surfaces having the same center opposed to each other on a pitch circle of the transmission hole group, and a pair of transmission surfaces provided between the transmission surfaces. A second feature is that the area is defined by the relief portion.

In addition to the second feature of the present invention, the angle β around the center of the transmission hole of each of the pair of relief portions is expressed by the following formula 0.5 (180 ° -360 ° / P) ≦ β ≦ 180 ° -360 ° / P
However, the third feature is that P is set so that the number of the transmission pins is established.

  The deceleration drive member corresponds to the inner gear 7 in an embodiment of the present invention described later.

  According to the first feature of the present invention, the inner surface of each transmission hole is provided with a notch-shaped relief portion at a portion where the operation lock of the transmission pin is likely to occur, so that a manufacturing error is not particularly considered. Even if each transmission hole is formed to the required minimum diameter, the operation lock of the transmission pin can be avoided, and therefore, an increase in backlash between the transmission hole and the transmission pin can be suppressed. Even in such a case, it is possible to prevent the generation of noise and the decrease in the reverse response of the output shaft.

  In addition, since each transmission pin can be a circular cross-section as in the past, a roller can be attached to the outer periphery of the transmission pin to reduce the frictional resistance between the transmission pin and the inner surface of the transmission hole, thereby improving the transmission efficiency. it can.

  According to the second feature of the present invention, a highly accurate transmission surface can be easily finished by drilling or the like.

  According to the third feature of the present invention, it is possible to satisfy both the high transmission efficiency of the transmission surface for the transmission pin and the escape function for the transmission pin of the escape portion.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a longitudinal side view of a cycloid reduction gear according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, FIG. 3 is an enlarged view of a part 3 of FIG. It is explanatory drawing.

  1 and 2, the input shaft 2 is rotatably supported on the left side wall 1a of the casing 1 via a pair of left and right ball bearings 4, and the input shaft 2 and the axis A1 are connected to the right side wall 1b. The output shafts 3 arranged in a row are rotatably supported via a pair of ball bearings 5. The input shaft 2 and the output shaft 3 are connected by a cycloid reduction gear R in a transmission chamber 1 c in the casing 1.

  The cycloid reduction gear R is formed integrally with the input shaft 2 and has an eccentric shaft 2a having an axis A2 that is eccentric by a minute distance e with respect to the axis A1, and is rotatably fitted to the eccentric shaft 2a. A concentric eccentric ring 6, an inner gear 7 that is rotatably supported on the outer periphery of the eccentric ring 6, a concentric inner gear 7 that is fixed to the casing 1 concentrically with the input shaft 2, and in mesh with the inner gear 7. The outer gear 8, the inner gear 7, a driven member 9 that is fixed to the output shaft 3 with the side surfaces facing each other, and a joint 10 that connects the inner gear 7 and the driven member 9 to each other.

  The outer gear 8 is composed of a large number of fixing pins 8a that are arranged at equal intervals on a pitch circle C1 centered on the axis A1 of the input shaft 2 and are attached to the left side wall of the casing 1. Each roller 8b is mounted. The inner gear 7 is meshed with the outer peripheral portion of the fixing pin 8a, that is, the roller 8b. Accordingly, the fixing pin 8a with the roller 8b corresponds to the teeth of the outer gear 8, and the number of teeth of the outer gear 8 is slightly larger than the number of teeth of the inner gear 7. In the illustrated example, the inner gear 7 has 22 teeth and the outer gear 8 has 23 teeth.

  The joint 10 is composed of a large number of odd-numbered transmission holes 11 formed in the inner gear 7 and transmission pins 12 of the same number as the transmission holes 11 that are attached to the driven members 9 and are loosely fitted to the transmission holes 11 respectively. The A large number of transmission holes 11 are arranged at equal intervals on a pitch circle C2 centered on the axis of the inner gear 7 (= the axis A2 of the eccentric ring 6), and the large number of transmission pins 12 are connected to the output shaft 3 Are arranged at equal intervals on a pitch circle C3 centering on the axis (= axis A1 of the input shaft 2). The transmission pin 12 is formed so that its cross-sectional shape is circular, and a roller 13 is mounted on the outer periphery thereof.

  As clearly shown in FIG. 3, each transmission hole 11 has a circular hole as a basic shape. On the inner surface of the transmission hole 11, a pitch circle of the transmission hole 11 group passing through the center c of the transmission hole 11. A notch-shaped relief portion 11b that prevents interference with the transmission pin 12 is provided in both portions facing each other on the radius line r of C2. Accordingly, each transmission hole 11 includes a pair of concentric arcuate transmission surfaces 11a facing each other on the pitch circle C2, and a pair of notched relief portions 11b provided between the transmission surfaces 11a. It will be defined by.

  Next, the operation of this embodiment will be described with reference to FIGS.

  FIG. 4 shows the operation of the cycloid reduction gear R. In order to facilitate understanding, the transmission hole 11 has two opposing holes across the axis A2 of the inner gear 7, and the transmission pin 12 has a driven member. Nine axes (= the axis of the input shaft 2) are opposed to each other and the two are opposed to each other.

  Now, when the input shaft 2 is rotated in the direction of the arrow D, the eccentric wheel 6 revolves around the axis A1 of the input shaft 2, so that the inner gear 7 rotatably supported on the outer periphery of the eccentric wheel 6 is When the input shaft 2 is revolved around the axis A1 and the input shaft 2 rotates once, the inner gear 7 revolves once and returns to the original position while changing the meshing position with the outer gear 8. During this time, the inner gear 7 decelerates and rotates in a direction opposite to the rotational direction D of the input shaft 2 by an angle corresponding to the difference between the number of teeth of the inner gear 7 and the number of teeth of the outer gear 8, that is, the number of fixed pins 8a. Forced. As shown in the example, when the number of teeth of the outer gear 8 is 23 and the number of teeth of the inner gear 7 is 22, the reduction ratio is 1/22. The rotation of the inner gear 7 is transmitted to the driven member 9 through the joint 10 and to the output shaft 3.

  The operation of the joint 10 during this period will be described. The revolution of the inner gear 7 is absorbed by the eccentric motion of each transmission hole 11 with respect to each transmission pin 12, and the rotation of the inner gear 7 is shown in FIGS. 4 (B) and 4 (D). As described above, the transmission surface 11 a of some of the transmission holes 11 presses the outer peripheral surface of the transmission pin 12, so that it is transmitted to the driven member 9.

  By the way, as shown in FIGS. 4A, 4C and 4E, the transmission pin 12 is on or near the radial line r of the pitch circle C2 of the transmission hole 11 passing through the center c of the transmission hole 11. When coming, the transmission pin 12 approaches the portion of the inner surface of the transmission hole 11 that intersects the radius line r. At this time, if the transmission pin 12 comes into contact with the inner surface of the transmission hole 11, an operation lock is generated and the revolution of the inner gear 7 is disabled. Therefore, conventionally, a manufacturing error is sufficiently expected to avoid the operation lock. The transmission hole 11 is formed with a sufficiently large diameter as indicated by the chain line 11 '. In this case, the backlash between the transmission hole 11 and the transmission pin 12 increases due to the increase in the diameter of the transmission hole 11. Therefore, when the input shaft 2 is reversed, noise is generated and the reverse rotation response of the output shaft 3 is reduced.

  Therefore, in the present invention, the notch-shaped relief portion 11b is provided in the inner surface of each transmission hole 11 between the pair of opposing transmission surfaces 11a where the operation lock of the transmission pin 12 is likely to occur. Without special consideration, even if each transmission hole 11 is formed to the required minimum diameter, the operation lock of the transmission pin 12 can be avoided. Accordingly, an increase in backlash between the transmission hole 11 and the transmission pin 12 can be suppressed, and therefore, when the input shaft 2 is reversed, it is possible to prevent generation of noise and a decrease in the reverse rotation response of the output shaft 3. .

  In forming a pair of arcuate transmission surfaces 11a having the same center and a pair of notch-shaped relief portions 11b provided between the transmission surfaces 11a, for example, a pair of arcuate transmission surfaces 11a with finishing allowances are provided. And a pair of relief portions 11b connected to them by press, forging, injection molding, or the like, and then finishing the pair of arcuate transmission surfaces 11a with a drill or the like to obtain a highly accurate transmission surface 11a. The transmission hole 11 can be easily obtained. At this time, because of the presence of the escape portion 11b, there is no need to take into account a processing error, so that productivity can be improved.

  In addition, since each transmission pin 12 may have a circular cross section as before, a roller 13 is attached to the outer periphery of the transmission pin 12 to reduce the frictional resistance between the transmission pin 12 and the inner surface of the transmission hole 11 and improve the transmission efficiency. Can be achieved.

Here, when the inner gear 7 rotates, the angle range α of the transmission surface 11a on one side of the inner surface of each transmission hole 11 that contacts the transmission pin 12 is P.
α = 360 ° / P
Can be expressed as Therefore, the maximum value βmax of the angle range β of the relief portion 11b on one side between the transmission surfaces 11a is
βmax = {360 ° − (360 ° / P) × 2} / 2
Thus, if β is too small, the relief portion 11b does not exhibit the escape function with respect to the original transmission pin 12. Therefore, it is desirable that the minimum value βmin of β is 50% of βmax.

  Therefore, it is desirable to set the angle range β of the relief portion 11b on one side so that the following equation (1) is satisfied.

0.5 (180 ° -360 ° / P) ≦ β ≦ 180 ° -360 ° / P (1)
Thus, it is possible to satisfy both the high transmission efficiency of the transmission surface 11a with respect to the transmission pin 12 and the escape function of the escape portion 11b with respect to the transmission pin 12.

  The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the invention. For example, the transmission hole 11 and the transmission pin 12 can be replaced with each other. Specifically, contrary to the above embodiment, the transmission pin 12 may be attached to the inner gear 7 and the transmission hole 11 may be provided in the driven member 9.

The longitudinal section side view of the cycloid reduction gear concerning the example of the present invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. FIG. 3 is an enlarged view of part 3 of FIG. 2. Action | operation explanatory drawing of a cycloid reduction gear.

Explanation of symbols

A1... Input and output shaft axis A2 ... Deceleration drive member (inner gear) axis C2 ... Pitch circle c of transmission hole group ... Center of transmission hole r ...・ Radial line R of pitch circle of transmission hole group …… Cycloid reducer 2 …… Input shaft 3 …… Output shaft 7 …… Deceleration drive member (inner gear)
9 ... driven member 10 ... joint 11 ... transmission hole 11a ... transmission surface 11b ... relief part 12 ... transmission pin

Claims (3)

A deceleration drive member (7) that is forced to decelerate and rotate while revolving around the axis (A1) of the input shaft (2) as the input shaft (2) rotates, and the input shaft (2) and the axis (A1) Are provided between a driven member (9) integrally connected to an output shaft (3) arranged with the same, and a reduction drive member (7) and a driven member (9), and the reduction drive member (7) And a joint (10) for transmitting rotation to the driven member (9). The joint (10) is equidistant on a pitch circle (C2) centered on the axis (A2) of the deceleration drive member (7). The driven members are arranged at equal intervals on a plurality of first transmission parts provided on the deceleration drive member (7) so as to be arranged on the pitch circle (C3) centering on the axis (A1) of the output shaft (3). It is comprised with the some 2nd transmission part provided in (9), and one of these 1st and 2nd transmission parts is And Doana (11), the other is in the transmission pin (12) and the cycloid reduction gear loosely fitting to said transmission hole (11),
A transmission pin (12) is formed so that the cross-sectional shape thereof is circular, and the inner surface of the transmission hole (11) passes through the center (c) of the transmission hole (11). A cycloid reducer characterized in that a notch-shaped relief portion (11b) for preventing interference with the transmission pin (12) is provided at both portions facing each other on the radial line (r) of the pitch circle (C2) . The cycloid reducer according to claim 1,
The transmission hole (11) is provided between a pair of arcuate transmission surfaces (11a) having the same center opposite to each other on the pitch circle (C2) of the transmission hole (11) group, and the two transmission surfaces (11a). A cycloid speed reducer defined by a pair of the relief portions (11b). The cycloid reducer according to claim 2,
The angle β around the center (c) of the transmission hole (11) of each one of the pair of relief portions (11b) is expressed by the following formula 0.5 (180 ° -360 ° / P) ≦ β ≦ 180 ° − 360 ° / P
However, P: The cycloid reduction gear characterized by setting so that the number of the said transmission pins (12) may be materialized.

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