JP2021004656A - Orthogonal axis speed reducer - Google Patents

Abstract

To obtain an orthogonal axis speed reducer which enables easy backlash adjustment.SOLUTION: An orthogonal axis speed reducer 100 includes: a first speed reduction part 1 having a bevel pinion 11 and a bevel gear 12 which rotates around an axis O2 orthogonal to an axis O1 of the bevel pinion 11 and engages with the bevel pinion 11; an eccentric swing type second speed reduction part 2 including an internal gear 21, a hollow input shaft 24 including an eccentric part 33, an external gear 20 which is installed on the exterior side of the eccentric part 33 and engages with the internal gear 21 from the inner side while swinging, and a carrier 23 which extracts relative rotation between the internal gear 21 and the external gear 20 as an output; a housing 3a incorporating the first speed reduction part 1; and a cylindrical member 4 which is fixed to the housing 3a, penetrates through the bevel gear 12 and the input shaft 24, and covers an opening 5 of the housing 3a. The bevel gear 12 is fixed to an end part at the opening 5 side of the housing 3a in the input shaft 24. The bevel gear 12 is disposed in a direction such that a tooth surface 12a faces the second speed reduction part 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to an orthogonal axis speed reducer capable of easily performing backlash adjustment.

Conventionally, Patent Document 1 discloses an orthogonal axis type power transmission device mainly used for driving a robot joint or the like. In this device, a transmission member (bevel gear) is supported from the inner peripheral side via a bearing by a tubular member arranged so as to penetrate the center of the speed reducer. According to this device, since the bevel gear is supported from the inner peripheral side by the tubular member, it is possible to reduce the shaft deviation of the input shaft. Further, the bevel gear is connected to the end of the input shaft via a bolt with the tooth surface facing the anti-second speed reduction device side in the axial direction (left side in FIG. 1), and meshes with the bevel pinion.

Japanese Unexamined Patent Publication No. 2013-199981

Reducers used in robots and the like are required to have a smaller backlash in order to perform highly accurate positioning work. In the case of an orthogonal axis type speed reducer including a bevel pinion and a bevel gear as in Patent Document 1, it is particularly necessary to finely adjust the tooth contact of the gear in the orthogonal axis portion to reduce the backlash. However, according to the configuration of Patent Document 1, when finely adjusting the position of the bevel gear, it is necessary to remove the tubular member and the bevel pinion, which causes a problem that it takes time and effort.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an orthogonal axis speed reducer capable of easily performing backlash adjustment.

In order to achieve this object, the orthogonal axis speed reducer according to claim 1 rotates about a first bevel gear and an axis orthogonal to the axis of the first bevel gear, and is the first bevel gear. A first reduction gear having a second bevel gear that meshes with the internal gear, an internal gear, a hollow input shaft provided with an eccentric portion, and a small difference in the number of teeth from the internal gear that is externally attached to the eccentric portion. A second eccentric swing type equipped with an external gear that internally engages with the internal gear while swinging, and an output unit that takes out the relative rotation of the internal gear and the external gear as an output. A tubular shape that is fixed to the housing, penetrates the inside of the second bevel gear and the input shaft, and covers the opening of the housing, and the housing containing the first speed reduction unit. An orthogonal shaft speed reducer having a member, the second bevel gear is fixed to the end of the housing on the input shaft on the opening side, and the second bevel gear is It is characterized in that the tooth surface is arranged so as to face the second deceleration portion.

The orthogonal shaft reducer according to claim 2 is the orthogonal shaft reducer according to claim 1, and further, a bearing that supports the input shaft or the second bevel gear on the tubular member. Is not provided, and the tubular member is arranged with a slight gap in the radial direction with respect to the input shaft and the second bevel gear.

The orthogonal shaft speed reducer according to claim 3 is the orthogonal shaft speed reducer according to claim 1 or 2, and further, the inner peripheral surface of the housing is formed from the opening to the second speed reduction unit. It is characterized in that the inner diameter becomes smaller toward the direction.

The orthogonal shaft speed reducer according to claim 4 is the orthogonal shaft speed reducer according to claim 3, and the inner diameter of the inner peripheral surface of the housing overlaps with the axis of the first bevel gear. It is characterized in that the position is smaller than the outer diameter of the second bevel gear.

According to the orthogonal shaft reducer according to claim 1, the second bevel gear is fastened to the end on the opening side of the input shaft, and the tooth surface of the second bevel gear faces the second reduction gear. It is arranged in the direction of Therefore, the second bevel gear can be removed by simply removing the tubular member, and the position of the second bevel gear can be finely adjusted.

Further, in the structure in which the bevel gear is pivotally supported by the tubular member as in Patent Document 1, the bevel gear is not held when the tubular member is removed, so that the tooth contact may change and the backlash adjustment may not be performed correctly. However, according to the orthogonal axis speed reducer according to claim 2 of the present invention, since the bevel gear is not pivotally supported by the tubular member, the backlash adjustment can be reliably performed.

Further, according to the orthogonal axis speed reducer according to claim 3, since the inner peripheral surface of the housing becomes smaller from the opening toward the second reduction gear, an extra inside of the orthogonal shaft speed reducer is obtained. Since the space can be narrowed, the lubricant sealed inside is easily guided to the meshing portion between the first bevel gear and the second bevel gear, and the lubrication performance is improved.

Further, according to the orthogonal axis speed reducer according to claim 4, the inner diameter of the inner peripheral surface of the housing is smaller than the outer diameter of the second bevel gear at a position overlapping the axis of the first bevel gear. The lubricant sealed inside is easily guided by the meshing portion between the first bevel gear and the second bevel gear, and the lubrication performance is further improved.

It is a central vertical sectional view of the orthogonal axis speed reducer of 1st Embodiment. It is a central vertical sectional view of the orthogonal axis reduction gear of 2nd Embodiment.

[First Embodiment]
Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a central vertical cross-sectional view of the orthogonal axis reducer 100, which is the first embodiment of the orthogonal axis reducer of the present invention.

The orthogonal axis speed reducer 100 includes a first speed reduction unit 1, a second speed reduction unit 2, a housing 3a, and a tubular member 4. The first deceleration unit 1 is built in the housing 3a, and the second deceleration unit 2 is connected to the housing 3a. One end of the tubular member 4 is fixed to the housing 3a, and the other end is arranged so as to coaxially penetrate the center of the second deceleration portion 2.

The first deceleration unit 1 is an orthogonal axis type deceleration unit, and is a second gear that rotates around a bevel pinion 11 which is a first bevel gear and an axis O2 orthogonal to the axis O1 of the bevel pinion 11 and meshes with the bevel pinion 11. It is provided with a bevel gear 12 which is a bevel gear of 2. The bevel gear 12 is connected to the end 24a on the input side of the input shaft 24 of the second deceleration unit 2, which will be described later, with the tooth surface 12a facing the second deceleration unit 2. The bevel gear 12 is fixed to the end portion 24a of the input shaft 24 by a plurality of bolts 13, 13, ..., Is coaxial with the input shaft 24, and can rotate integrally with the input shaft 24. The bevel pinion 11 is provided with a connecting portion 14 that can be connected to a motor (not shown) on the side opposite to the teeth that mesh with the bevel gear 12, and is rotatably shafted inside the housing 3a via two ball bearings 15 and 15. It is supported. Further, an oil seal 16 is arranged between the housing 3a and the bevel pinion 11 inside the ball bearing 15.

The second deceleration unit 2 is an eccentric swing type deceleration unit in which the external gear 20 rotates eccentrically while meshing with the internal gear 21. The second reduction gear portion 2 includes a casing 22, a carrier 23, an external gear 20, and an input shaft 24. The casing 22 has a cylindrical inner case 26 in which an internal gear 21 is integrally provided on the inner peripheral surface, and a cylindrical inner case 26 arranged on one end surface (output side, left side in FIG. 1) in the axial direction of the inner case 26. The inner case 26 and the outer case 27 are formed by a plurality of bolts 28, 28, which penetrate the inner case 26 and are screwed into the outer case 27. From (input side, right side in FIG. 1), it is integrally connected to the housing 3a. An O-ring 29 for sealing is sandwiched between the inner case 26 and the outer case 27 in the casing 22. Further, an O-ring 30 for sealing is sandwiched between the inner case 26 and the housing 3a. The outer case 27 also serves as the outer ring of the cross roller bearing 31.

The carrier 23 is composed of a first carrier member 23a and a second carrier member 23b. The first carrier member 23a is rotatably supported inside the outer case 27 via a cross roller bearing 31. The first carrier member 23a also serves as an inner ring of the cross roller bearing 31. A plurality of bolt holes (not shown) are formed on one end surface of the first carrier member 23a in the axial direction, and the bolt holes are used to connect to the other side device and transmit power to the other side device.

Inside the casing 22, a hollow tubular input shaft 24 is coaxial with the axis of the internal gear 21 via two ball bearings 32 and 32, and is attached to the first carrier member 23a and the second carrier member 23b. It is rotatably supported. In the input shaft 24, a pair of eccentric portions 33, 33 having the same outer diameter and eccentricity δ1 and having phases different from each other by 180 degrees are formed adjacent to each other between the ball bearings 32, 32. .. Each of the eccentric portions 33, 33 is provided with a needle bearing 34 formed of a plurality of rollers having a circular cross section arranged over the entire circumference, and two external gears 20 are provided via the needle bearing 34. , 20 are rotatably decorated. A plurality of bolt holes 25 are formed at the end portion 24a on the input side in the axial direction of the input shaft 24.

Two external gears 20 and 20 having the same shape are arranged on the other side of the first carrier member 23a in the axial direction, and the first carrier member 23a and the second carrier member 23b have two external gears 20 and 20. It is designed to sandwich 20. The external gears 20 and 20 have a number of teeth slightly smaller (about 1 to 6) than the number of teeth of the internal gear 21, and are inscribed in the internal gear 21 at an eccentric position. In the external gears 20 and 20, a plurality of circular pin holes 35 are formed at equal intervals in the circumferential direction on a concentric circle centered on the axis O3 offset by the eccentricity δ1 from the axis O2 of the bevel gear 12. In the pin holes 35, pins 36 erected in parallel with the axis on a concentric circle centered on the axis O2 of the bevel gear 12 are loosely inserted. Both ends of the pin 36 are press-fitted into holes provided in the first carrier member 23a and the second carrier member 23b, and the pin 36 allows the first carrier member 23a and the second carrier member 23b to rotate integrally. .. A bolt hole is provided at one end of the pin 36, and a bolt 37 is screwed into the bolt hole from the side of the first carrier member 23a. The head of the bolt 37 is housed in a counterbore portion 38 provided on the side of the first carrier member 23a, and the head of the bolt 37 restricts the movement of the pin 36 toward the second carrier member 23b in the axial direction. A tubular metal 39 is integrally outered on the free insertion portion of the external gear 20 on the outer circumference of the pin 36.

An oil seal 40 is arranged on the outside of the cross roller bearing 31 between the outer case 27 and the first carrier member 23a. Further, an oil seal 41 is arranged on the outside of the ball bearing 32 between the first carrier member 23a and the tubular member 4. The internal space of the orthogonal axis speed reducer 100 is sealed by the oil seal 16, the oil seal 40, the oil seal 41, the O-ring 29, the O-ring 30, and the O-ring 48 described later.

The tubular member 4 is a cylindrical member molded from, for example, iron, and coaxially penetrates the fixing portion 42 fixed to the opening 5 of the housing 3a, the second deceleration portion 2, and the bevel gear 12. It is composed of a main body portion 43 whose tip reaches the inside of the first carrier member 23a. In the tubular member 4, the fixing portion 42 is arranged so as to cover the opening 5 of the housing 3a, only the fixing portion 42 side is fixed to the housing 3a, and the lip of the oil seal 41 is attached to the main body portion 43 side. It only abuts and is not shaft-supported. That is, the tubular member 4 is fixed to the housing 3a in a so-called cantilevered state. The main body 43 of the tubular member 4 is arranged with a slight gap A separated from the input shaft 24 or the inner peripheral surface of the bevel gear 12. In this embodiment, the gap A is about 0.5 mm to 1 mm.

The fixing portion 42 of the tubular member 4 is composed of a circular flange portion 44 and an inro portion 45, and the inro portion 45 is fitted to the inner peripheral surface 6 of the opening 5 provided in the housing 3a, and the flange portion The 44 is fixed to the housing 3a by a plurality of bolts 46, 46 ... Further, a groove 47 is provided on the end surface of the opening 5 of the housing 3a facing the flange portion 44 over the entire circumference, and an O-ring 48 is arranged in the groove 47. An O-ring 48 seals between the opening 5 of the housing 3a and the flange 44 of the tubular member 4.

In the orthogonal axis speed reducer 100 configured as described above, when the bevel pinion 11 is rotated by a motor (not shown), the bevel gear 12 that meshes with the bevel pinion 11 rotates, and the input shaft 24 connected to the bevel gear 12 rotates. As the input shaft 24 rotates, the eccentric portions 33 and 33 move symmetrically, and the external gears 20 and 20 move eccentrically and rotate in the state of being inscribed in the internal gear 21. Therefore, each pin hole 35 also eccentrically and rotates on its axis, but since each pin hole 35 is formed to have a larger diameter than the pin 36 including the metal 39, each pin 36 is inscribed in the pin hole 35. The eccentric movement is relatively eccentric to absorb the eccentric component, and only the rotation component is extracted from each pin 36. Therefore, the first carrier member 23a and the second carrier member 23b rotate synchronously via the pin 36, and the rotation is transmitted from the output unit, the first carrier member 23a, to the counterpart device. At this time, the grease filled in the housing 3a is sealed by the oil seal 16, the oil seal 40, the oil seal 41, the O-ring 29, the O-ring 30, and the O-ring 48.

Next, a method of finely adjusting the tooth contact between the bevel pinion 11 and the bevel gear 12 of the first reduction gear 1 will be described in order to further reduce the backlash of the orthogonal axis speed reducer 100 of the above embodiment. In the case of orthogonal type gears, the tooth contact can be adjusted by moving each gear in the respective axial direction. When finely adjusting the position of the bevel pinion 11, the bevel pinion 11 and the ball bearing 15 can be finely adjusted by removing the bevel pinion 11 and the ball bearing 15 from the housing 3a and inserting a predetermined amount of shims between the housing 3a and the ball bearing 15. is there. When finely adjusting the position of the bevel gear 12, the tubular member 4 is removed, the bevel gear 12 is removed by removing the bolt 13, and a predetermined amount of shims are sandwiched between the bevel gear 12 and the end portion 24a of the input shaft 24. , Fine adjustment is possible.

As described above, according to the orthogonal axis speed reducer 100 of the above-described embodiment, the bevel gear 12 can be removed by removing the tubular member 4, and it is not necessary to remove the bevel pinion 11 when finely adjusting the position of the bevel gear 12. .. Therefore, the backlash adjustment can be facilitated.

Further, in the present embodiment, since there is no bearing or the like that supports the input shaft 24 or the bevel gear 12 by the tubular member 4, the backlash adjustment is easy. If a structure including such a bearing is considered, when the tubular member 4 is removed, the bearing that pivotally supports the bevel gear 12 is also removed at the same time, and the bevel gear 12 is not pivotally supported. Therefore, the gears mesh with each other. The state will change, making it difficult to adjust the backlash.

[Second Embodiment]
Next, the second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the shape of the inner peripheral surface 6 of the housing 3b is different from that of the first embodiment. Since the configuration and operation of the orthogonal axis speed reducer 200 except for the shape of the inner peripheral surface 6 of the housing 3b are the same as those in the first embodiment described above, detailed description thereof will be omitted.

FIG. 2 is a central vertical sectional view of the orthogonal axis reducer 200, which is the second embodiment of the orthogonal axis reducer of the present invention. The inner peripheral surface 6 of the housing 3b of the orthogonal axis speed reducer 200 is circular, and is inclined so that the inner diameter gradually decreases from the opening 5 toward the second speed reduction unit 2. For example, when the housing 3b is molded by casting or the like, such an inclination can be obtained by giving a draft of the mold. Further, the inner diameter D2 of the inner peripheral surface 6 at a position overlapping the axis O1 of the bevel pinion 11 is smaller than the outer diameter D1 of the bevel gear 12 (D1> D2).

Also in the second embodiment, the same effect as that of the first embodiment is obtained. Further, since the inner diameter of the inner peripheral surface 6 of the housing 3b becomes smaller from the opening 5 toward the second reduction gear 2, the extra space inside the orthogonal axis speed reducer 200 can be narrowed. .. Therefore, the lubricant enclosed inside is easily guided to the meshing portion between the bevel pinion 11 and the bevel gear 12, and the lubrication performance is improved.

Further, since the inner diameter of the inner peripheral surface 6 of the housing 3b is smaller than the outer diameter D1 of the bevel gear 12 at the position where it overlaps with the axis O1 of the bevel pinion 11, the lubricant sealed inside is the bevel pinion 11 and the bevel gear 12. It becomes easier to be guided by the meshing part with, and the lubrication performance is further improved.

Although the present embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. An example of changes that can be made to the above embodiment will be described below.

For example, in the present embodiment, the material of the tubular member 4 is iron, but the material may be an aluminum alloy, resin, or the like. Since the tubular member 4 does not support the input shaft 24 or the bevel gear 12, in principle, no load is applied to the tubular member 4. Therefore, a material such as an aluminum alloy or a resin having a strength lower than that of iron may be used.

Further, for example, the first bevel gear of the present invention may be a hypoid pinion, and the second bevel gear may be a hypoid gear.

Further, for example, in the present embodiment, the inner peripheral surface 6 of the housing 3b is circular, but the inner peripheral surface 6 has a shape other than a circular shape such as a quadrangle or another polygon, as appropriate, in accordance with the shape of the housing 3b. It may be.

100,200 Orthogonal axis reducer 1 1st reduction unit 2 2nd reduction unit 3a, 3b Housing 4 Cylindrical member 5 Opening 6 Inner peripheral surface 11 Bevel pinion 12 Bevel gear 12a Tooth surface (bevel gear)
20 External gear 21 Internal gear 23 Carrier 23a First carrier member 24 Input shaft 24a End (input shaft)
33 Eccentric part O1 Bevel pinion axis O2 Bevel gear axis D1 Bevel gear outer diameter A Gap

Claims (4)

A first reduction gear having a first bevel gear and a second bevel gear that rotates about an axis orthogonal to the axis of the first bevel gear and meshes with the first bevel gear.
An internal gear, a hollow input shaft having an eccentric portion, and an external tooth that is externally attached to the eccentric portion and has a slight difference in the number of teeth from the internal gear and engages with the internal gear while swinging. An eccentric swing type second deceleration unit including a gear and an output unit that takes out the relative rotation of the internal gear and the external gear as an output.
A housing containing the first deceleration unit and
A tubular member fixed to the housing, penetrating the inside of the second bevel gear and the input shaft, and covering the opening of the housing.
Orthogonal axis reducer with
The second bevel gear is fixed to the end of the housing on the input shaft on the opening side.
The second bevel gear is an orthogonal axis speed reducer characterized in that the tooth surface is arranged in a direction facing the second speed reduction portion. The tubular member is not provided with a bearing that supports the input shaft or the second bevel gear.
The orthogonal shaft speed reducer according to claim 1, wherein the tubular member is arranged with a slight radial gap between the input shaft and the second bevel gear. The orthogonal axis speed reducer according to claim 1 or 2, wherein the inner peripheral surface of the housing has an inner diameter that decreases from the opening toward the second speed reduction portion. The orthogonal axis deceleration according to claim 3, wherein the inner diameter of the inner peripheral surface of the housing is smaller than the outer diameter of the second bevel gear at a position overlapping the axis of the first bevel gear. Machine.