JP2010216591A - Reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably support a shaft by a small bearing having heat resistance and high rigidity. <P>SOLUTION: A reduction gear 30 has in a casing 368 reduction mechanisms 31 and 32 having a first shaft 317 and a second shaft 321 having an inclination θ to the axis X of the first shaft 317 and transmitting motive power of the first shaft 317, and has a cross roller bearing 329 having a rolling element 337 between an inner ring 335 and an outer ring 336 for supporting the first shaft 317 or the second shaft 321. A joining part 366A of a part Z1 for storing at least a part of the first shaft 317 and a part Z2 for storing at least a part of the second shaft 321 among the casing 368, uses the outer ring 336 of the cross roller bearing 329 in common. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reduction gear.

  Patent Document 1 discloses a reduction gear 103 as shown in FIG.

  The speed reducer 103 includes a swing speed reducing portion 104 having a swing inner meshing planetary gear structure and an orthogonal speed reducing portion 105.

  The rotational power of the swing speed reducing unit 104 is extracted from the carrier 112. Rotational power is output from an output shaft 120 integrally connected to the bevel gear 118 by a bevel pinion 116 formed on the pinion shaft 114 and a bevel gear 118 (orthogonal transmission structure) meshing with the bevel pinion 116. In this conventional example, the inclination of the axis of the pinion shaft 114 and the output shaft 120 is 90 degrees.

  Here, the pinion shaft 114 is supported by a bearing 128, and the output shaft 120 is supported by a bearing 122. The inner and outer rings of the bearings 122 and 128 are assembled separately.

JP 2001-323968 (Claim 1, [0007], [0051], FIG. 2)

  Conventionally, the size of a bearing such as an output shaft is determined in consideration of heat generated around the bearing in addition to the torque of the bearing. For this reason, for example, in the case where the output shaft or the like rotates at a high speed, it is necessary to further improve the heat resistance, and as a result, the bearing has become larger.

  On the other hand, as a technique to prevent the bearing from becoming large in order to cope with the heat generation of the bearing, for example, the rotational speed of the output shaft is limited, or a bearing with higher accuracy (smaller rattling) is adopted. Thus, it is conceivable to adopt a technique such as stabilizing the rotation of the shaft and suppressing the heat generation itself around the shaft.

  However, the limitation on the rotational speed is not always applicable, and the method of using a highly accurate bearing further increases the cost of the apparatus (in addition to the fact that the output shaft bearing is originally large and expensive). It will be.

  This invention is made | formed in view of this problem, Comprising: It makes it the subject to support a axis | shaft stably by a small, heat resistant, and highly rigid bearing.

  The present invention provides a speed reduction mechanism having a first shaft (pinion shaft) and a second shaft (output shaft) having an inclination with respect to the axis of the first shaft and transmitting the power of the first shaft. In the speed reducer provided inside, in order to support the first shaft or the second shaft, a rolling element is provided between the inner ring and the outer ring, and at least a part of the first shaft is accommodated in the casing. The above-mentioned problem is solved by adopting a configuration in which the joint portion between the portion that accommodates at least a part of the second shaft serves as the outer ring of the bearing.

  According to the present invention, the shape of the casing is positively utilized in the reduction gear provided in the casing with the reduction mechanism comprising the first axis and the second axis inclined with respect to the axis. That is, the part arrange | positioned in the junction part of a 1st, 2nd axis | shaft among this casing is used as an outer ring | wheel of a bearing.

  Accordingly, a particularly rigid portion of the casing can be directly used as the outer ring of the bearing, so that a highly rigid bearing can be obtained and the shaft can be stably supported, so that heat generation can also be suppressed.

  Moreover, the following synergistic effects are acquired by utilizing a part of casing as an outer ring | wheel directly. That is, for example, in the present invention, since the outer ring is also used as the casing of the reduction gear, there is no member boundary between the outer ring and the casing. Therefore, the heat generated in the rolling surface portion can be smoothly transmitted through the casing and dissipated to the outside, so that the heat dissipation performance of the generated heat is high. Accordingly, in combination with the absence of the outer ring, the bearing that has been increased (inevitable to increase) for heat capacity can be reduced in size. Or if it is the same magnitude | size, it can be set as a more heat-resistant bearing.

  Furthermore, it is not necessary to assemble the outer ring of the bearing separately, and the number of parts of the bearing can be reduced.

  According to the present invention, the shaft can be stably supported by a small, heat-resistant, and highly rigid bearing.

The longitudinal cross-sectional view of the reduction gear device concerning an example of embodiment of this invention Enlarged view of the part indicated by arrow II in FIG. Longitudinal sectional view of a reduction gear provided with a conventional orthogonal reduction gear

  First, a schematic configuration of a reduction gear device 30 according to an example of an embodiment of the present invention will be described.

  FIG. 1 shows a reduction gear 30.

  In this specification, for convenience, the upper side in the drawing is expressed as “upper side”. The lower side is similarly expressed based on the drawings.

  The reduction gear device 30 includes an output shaft (second shaft) 321 that has an inclination θ with respect to the pinion shaft (first shaft) 317 and the axis X of the pinion shaft 317 and to which the power of the pinion shaft 317 is transmitted. The speed reducing mechanism (the swing speed reducing mechanism 31 and the orthogonal speed reducing mechanism 32) is provided in the casing 368.

  In the present embodiment, the inclination θ of the axis X of the pinion shaft 317 and the axis Y of the output shaft 321 is a right angle (90 degrees).

  The casing 368 is manufactured using a casting technique. The casing 368 includes a first cover 360, a second cover 362, a third cover 364, and a fourth cover that are sequentially connected from the drive source (anti-load) side (right side: FIG. 1) to the load side (left side: FIG. 1). 366. Among these, the 4th cover 366 is comprised from the outer ring formation part 366A and the outer ring non-formation part 366B. The external shape is composed of a cylindrical portion (pinion shaft 317 insertion portion) and a dome-shaped portion (output shaft 321 insertion portion). The inside of the fourth cover 366 is hollow, and a hole for inserting the output shaft 321 is opened on the upper side and the lower side, and a hole for inserting the pinion shaft 317 is opened on the right side. ing.

  The upper and lower holes of the fourth cover 366 are provided with an oil seal 370 on the upper side and an oil seal 371 on the lower side, respectively, between the output shaft 321 and the oil inside the casing 368. The cross roller bearing 329, which will be described later, is sufficiently lubricated.

  The pinion shaft 317 side of the outer ring forming portion 366A is a joint portion 366A1 of a portion Z1 that accommodates a part of the pinion shaft 317 and a portion Z2 that accommodates a portion of the output shaft 321 (see FIG. 2: described later). ).

  Next, the configuration of the swing reduction mechanism 31 will be described.

  The swing reduction mechanism 31 includes a motor shaft 311, an internal gear 314, and external gears 319 (319 </ b> A and 319 </ b> B) that mesh with the internal gear 314 while swinging.

  Two eccentric bodies 312 (312A, 312B) are integrally formed on the motor shaft 311 with keys. An external gear 319 is incorporated on the outer periphery of the eccentric body 312 via rollers 340.

  The eccentric phase of each eccentric body 312 is shifted by 180 degrees, and the eccentric phase difference of the external gear 319 is 180 degrees.

  The external gear 319 has a slightly smaller number of teeth than the internal gear 314. The external gear 319 includes an internal pin hole 320 that passes through the external gear 319. The inner pin 315 is loosely fitted with the inner pin hole 320. An inner roller 324 is attached to the outer periphery of the inner pin 315 as a sliding acceleration member.

  Further, the inner pin 315 is fitted with the carrier 316. The carrier 316 corresponds to an output member of the swing reduction mechanism 31, is connected to a pinion shaft 317 that is an input shaft of the orthogonal reduction mechanism 32, and is fastened by a bolt 343.

  On the other hand, the internal gear 314 is held by a second cover 362 formed on the outer periphery of the pinion shaft 317 and a groove 341 formed on the inner peripheral surface of the second cover 362, and a plurality of teeth constituting the internal teeth by itself. And an outer pin 342.

  Next, the configuration of the orthogonal reduction mechanism 32 will be described.

  The orthogonal reduction mechanism 32 is an orthogonal transmission structure including a pinion shaft 317 and an output shaft 321. A bevel pinion 326 is cut directly at the tip of the pinion shaft 317. The bevel pinion 326 meshes with the bevel gear 325. The bevel gear 325 is attached to the inner ring 335 by a bolt 333, and the inner ring 335 is attached to the output shaft 321 by a bolt 330, so that the bevel gear 325 and the output shaft 321 can rotate integrally. Further, by removing the bolt 330, the output shaft 321 can be removed with the bearing 329 assembled to the casing 368.

  A bearing 327 installed on the inner periphery of the third cover 364 supports the carrier 316 and a bearing 328 rotatably supports the pinion shaft 317. A cross roller bearing 329, which will be described later, rotatably supports the output shaft 321.

  Here, the configuration of the cross roller bearing 329 will be described with reference to FIG.

  FIG. 2 shows an enlarged view (an enlarged view of a portion surrounded by II in FIG. 1) of the cross roller bearing 329 incorporated in the reduction gear 30 described above.

  The cross roller bearing 329 includes a roller (rolling element) 337 between the inner ring 335 and the outer ring 336.

  The outer ring 336 is an outer ring corresponding to the joint 366A1 of the casing 368, specifically, the portion Z1 that accommodates part of the pinion shaft 317 and the portion Z2 that accommodates part of the output shaft 321 in the fourth cover 366. It is integrated with the forming portion 366A. That is, the outer ring forming portion 366A also serves as the outer ring 336. On the side surface 336A facing the output shaft 321 (specifically, the inner ring 335) of the outer ring forming portion 366A, rolling surfaces 339 (339A, 339B) orthogonal to each other are formed toward the inner side. This rolling surface 339 is subjected to induction hardening in order to suppress wear deterioration and enable long-term use of the bearing.

  Specifically, the first rolling surface 339A is inclined from the arbitrary position of the side surface 336A in the oblique axis direction P1 (inwardly in the radial direction by 45 degrees toward the second rolling surface 339B described later). In) formed by cutting.

  Similarly, the second rolling surface 339B is cut from the other side of the side surface 336A in the oblique axial direction P2 (in a state inclined at 45 degrees radially inward toward the first rolling surface 339A). It is formed.

  On the other hand, the inner ring 335 is formed of a cylindrical member. On the side surface 335A of the inner ring 335, rolling surfaces 338 (338A, 338B) orthogonal to each other are formed toward the inner side of the inner ring 335 itself.

  Specifically, the first rolling surface 338A is directed in the oblique axial direction Q1 from the position facing the first rolling surface 339A of the outer ring forming portion 366A on the side surface 335A (toward the second rolling surface 338B described later). (Cut in a state inclined at 45 degrees radially inward).

  Similarly, the second rolling surface 338B extends in a diagonal axial direction Q2 from the position facing the second rolling surface 339B of the outer ring forming portion 366A on the side surface 335A (in the radial direction toward the first rolling surface 338A). It is cut and formed (inclined 45 degrees inward).

  The roller 337 has a cylindrical shape with the same diameter and height (the axial length of the roller 337) (strictly, the diameter is slightly smaller than the height), and every other roller is oriented at 90 degrees. It is changed and incorporated.

  The inner ring 335 is connected to the bevel gear 325 via a bolt 333 at the axial end thereof, and is fixed to the output shaft 321 via the bolt 330 at the opposite axial end.

  Next, the operation of the reduction gear device 30 will be described.

  When the eccentric body 312 is rotated by the rotation of the motor shaft 311, the external gear 319 mounted on the outer periphery of the eccentric body 312 via the roller 340 rotates while being inscribed in the internal gear 314. In this embodiment, since the internal gear 314 is fixed to the second cover 362, the free rotation of the external gear 319 is constrained and almost only swings inside the internal gear 314. As a result, relative rotation due to the difference in the number of teeth between the internal gear 314 and the external gear 319 occurs. This relative rotational component is transmitted to the carrier 316 corresponding to the output shaft of the speed reduction mechanism 31 via the inner pin 315. When the carrier 316 rotates, the pinion shaft 317 and the carrier 316 are spline-coupled so that the carrier 316 and the pinion shaft 317 rotate together. As a result, when the pinion shaft 317 rotates, the bevel pinion 326 directly cut at the tip of the pinion shaft 317 rotates, and the bevel gear 325 engaged with the bevel pinion 326 rotates. The rotation of the bevel gear 325 is transmitted to the output shaft 321 as it is.

  That is, a pair of bevel gears (orthogonal transmission structure) including a bevel pinion 326 and a bevel gear 325 can convert rotational power into a right angle direction (90 degrees) with a predetermined reduction ratio.

  Since the inner ring 335 is fixed to the bevel gear 325, the inner ring 335 rotates at the same rotational speed as the bevel gear 325.

  Next, the operation of the cross roller bearing 329 will be described.

  The outer ring 336 of the cross roller bearing 329 is formed in the outer ring forming portion 366A of the fourth cover 366.

  Thereby, it is not necessary to assemble the outer ring 336 of the cross roller bearing 329 separately from the device parts, and the number of parts of the cross roller bearing 329 can be reduced. As a result, the manufacturing cost of the entire reduction gear 30 can be reduced, and the structure of the reduction gear 30 can be simplified.

  In addition, since the external shape of the fourth cover 366 is as described above, and the surface area in contact with the external space is large, this is combined with the effect of using the outer ring 336 of the bearing 329 also as the fourth cover 366. Thus, the heat generated in the cross roller bearing 329 passes through the fourth cover 366 and is easily radiated to the external space. As a result, the bearing 329 is less likely to be deteriorated by heat, enabling long-term use, and extending the maintenance cycle of the reduction gear 30.

  In this embodiment, the inclination θ of the pinion shaft (first shaft) 317 and the output shaft (second shaft) 321 is a right angle (90 degrees), and the joint 366A1 accommodates a part of the pinion shaft 317 in the axial direction. In addition to having a portion Z1 that performs this, it has a portion Z2 that accommodates a portion of the output shaft 321 in the axial direction. That is, the cross-sectional area of the portion that functions as the outer ring 336 of the bearing 329 is large. Thus, the length of the portion Z2 that accommodates a part of the output shaft 321 in the axial direction reinforces the axial strength of the pinion shaft 317. The length of the portion Z1 that accommodates a part of the pinion shaft 317 in the axial direction reinforces the axial strength of the output shaft (second shaft) 321. As a result, the rigidity of the outer ring 336 of the cross roller bearing 329 can be increased.

  As a result, the output torque can be output stably, and an unexpected external force that can be input from the output side of the output shaft 321 can be dealt with. Further, since the durability of the cross roller bearing 329 can be improved, the life of the cross roller bearing 329 can be extended.

  In the present embodiment, the above-described cross roller bearing 329 is attached to the output shaft 321. The output shaft 321 is loaded with a torque larger than the torque applied to the pinion shaft 317 that is the input shaft.

  Therefore, there is an actual advantage of supporting the output shaft 321 by the cross roller bearing 329 having the outer ring 336 having high rigidity.

  From the above, by using the present invention, the output shaft 321 can be stably supported by the bearing 329 that is small, heat-resistant, and highly rigid.

  By the way, normally used cross roller bearings (types separately assembled in the apparatus) can be made compact in the axial direction by constituting a series while restricting the movement of the output shaft 321 in the axial direction. Has advantages.

  The cross roller bearing 329 according to the present embodiment has the advantages unique to the present invention described above, while maintaining the advantages of a normal cross roller bearing.

  In the present embodiment, the cross roller bearing having the outer ring that also serves as the casing is used to support the output shaft, but may be used to support the pinion shaft. Further, the inclination of the axis of the pinion shaft and the output shaft of the speed reduction mechanism may not be a right angle (90 degrees) (0 degree <θ <360 degrees).

  In this embodiment, the casing is used as an outer ring of a cross roller bearing, but it can also be used as an outer ring of a ball bearing, a needle bearing, or an angular roller bearing, and a similar effect can be obtained. Further, the casing is not limited to the one outer ring of the bearing described above, and a plurality of the outer rings may be provided to support the supported body at a plurality of locations.

30 ... Deceleration device 317 ... Pinion shaft (first shaft)
321 ... Output shaft (second axis)
329 ... Cross roller bearing 335 ... Inner ring 336 ... Outer ring 337 ... Roller (rolling element)
360, 362, 364, 366... 1st to 4th cover 366A...
368 ... Casing X ... Axis line of pinion shaft Y ... Axis line of output shaft θ ... Inclination of axis line of pinion shaft and output shaft Z1 ... Length of a portion that accommodates a part of pinion shaft Z2 ... A portion of an output shaft is accommodated Part length

Claims (2)

In a speed reducer provided with a speed reduction mechanism in a casing having a first axis and a second axis having an inclination with respect to the axis of the first axis and the power of the first axis being transmitted,
In order to support the first shaft or the second shaft, a bearing having a rolling element is provided between the inner ring and the outer ring,
Of the casing, a joint portion of a portion that accommodates at least a part of the first shaft and a portion that accommodates at least a portion of the second shaft also serves as an outer ring of the bearing. Reducer. In claim 1,
The speed reducing device, wherein the bearing is a cross roller bearing.

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