JP6941936B2 - Decelerator - Google Patents

Description

The present invention relates to a speed reducer.

A speed reducing device used for a joint portion of an arm of an industrial robot is known (for example, Patent Document 1). In this speed reducer, the relative rotation of the internal gear and the external gear is taken out as the relative rotation of the casing and the carrier member. Therefore, the casing and the carrier member are configured to be relatively rotatable via a bearing having a large diameter, that is, a large load capacity, which is called a “main bearing”.

Japanese Unexamined Patent Publication No. 2009-250279

For example, depending on the industrial machine in which the speed reducer is incorporated, such as the arm of an industrial robot, or depending on the application of the industrial machine, a large moment load is applied to the main bearing of the speed reducer from the industrial machine side. , High resistance to moment load, that is, large moment rigidity is required.

On the other hand, the reduction gear is required to be further miniaturized. As one of the methods for realizing miniaturization, a cross roller bearing is adopted as the main bearing. When a cross roller bearing is used, high moment rigidity can be obtained by applying an internal preload, but due to the characteristics of the rollers moving while sliding, applying an internal preload dramatically increases the rotational torque and shortens the service life. Therefore, it is not preferable. Therefore, ensuring a large moment stiffness is not so simple.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a reduction gear having a relatively high moment rigidity of a main bearing while being compact.

In order to solve the above problems, the speed reducer according to an embodiment of the present invention includes a casing, an internal gear provided in the casing, an external gear that meshes with the internal gear, and a rotation component or revolution of the external gear. A speed reducer including a carrier member synchronized with a component and a main bearing arranged between the casing and the carrier member. The main bearing is an outer ring provided on one of the casing and the carrier member, and a casing. And an inner ring provided on the other side of the carrier member, and a plurality of tapered rollers arranged between the outer ring and the inner ring. As for the plurality of tapered rollers, the first tapered roller and the second tapered roller that rolls on a rolling surface different from the first tapered roller are alternately arranged in the circumferential direction, and the internal gear and the external gear mesh with each other. At least a part of the part is the first intersection, which is the intersection of the extension lines of the rolling surface of the first taper roller on the outer ring and the rolling surface of the first taper roller on the inner ring on the same plane, and the second taper on the outer ring. It is located between the rolling surface of the roller and the second intersection, which is the intersection of the extension lines on the same plane of the rolling surface of the second tapered roller on the inner ring.

It should be noted that any combination of the above components and those in which the components and expressions of the present invention are mutually replaced between methods, devices, systems and the like are also effective as aspects of the present invention.

According to the present invention, it is possible to provide a speed reducer having a relatively high moment rigidity of a main bearing while being compact.

It is sectional drawing which shows the reduction gear which concerns on 1st Embodiment. 2 (a) to 2 (c) are enlarged cross-sectional views showing the main bearing. It is sectional drawing which shows the reduction gear which concerns on 2nd Embodiment. It is sectional drawing which shows the reduction gear which concerns on 3rd Embodiment. It is sectional drawing which shows the reduction gear which concerns on 4th Embodiment.

Hereinafter, the same or equivalent components, members, and processes shown in the drawings shall be designated by the same reference numerals, and redundant description will be omitted as appropriate. In addition, the dimensions of the members in each drawing are shown enlarged or reduced as appropriate for easy understanding. In addition, some of the members that are not important for explaining the embodiment in each drawing are omitted and displayed.

(First Embodiment)
FIG. 1 is a cross-sectional view showing a speed reducing device 100 according to the first embodiment. The speed reduction device 100 is a center crank type eccentric swing type speed reduction device. The speed reducing device 100 is used, for example, at a joint portion between a first arm on the root side and a second arm on the tip side, which constitute an arm of an industrial robot. The speed reducing device 100 decelerates the rotation of the motor incorporated in the first arm and outputs it to the second arm, thereby rotating the second arm relative to the first arm.

The speed reducing device 100 includes an input shaft 2, eccentric bodies 4, 6, 8, rollers 10, 12, 14, external gears 16, 18, 20, a first carrier member 26, and a second carrier member 28. A casing 36, a main bearing 38, and an internal gear 40 are provided.

The input shaft 2 is connected to a rotary drive source such as a motor, and rotates about the rotary shaft R of the speed reducer 100 (internal gear 40). The input shaft 2 is integrally formed with the input shaft 2 and three eccentric bodies 4, 6 and 8 whose axes are deviated from each other. The three eccentric bodies 4, 6 and 8 are eccentric with a phase difference of 120 degrees from each other. The eccentric bodies 4, 6 and 8 may be formed separately from the input shaft 2 and then fixed to the input shaft 2 by a key or the like.

Three external gears 16, 18 and 20 are swingably fitted on the outer circumferences of the eccentric bodies 4, 6 and 8 via rollers 10, 12 and 14, respectively. A plurality of offset through holes 16a, 18a, 20a are formed in the external gears 16, 18 and 20, respectively, at positions offset from the axis. The plurality of offset through holes 16a, 18a, 20a are formed at equal intervals in the circumferential direction.

The inner pin 22 and the inner roller 24 fitted on the inner pin 22 are axially penetrated through the offset through holes 16a, 18a, and 20a. A gap corresponding to twice the eccentric amount of the eccentric bodies 4, 6 and 8 is secured at the maximum between the inner roller 24 and the offset through holes 16a, 18a and 20a. In the inner roller 24, the outer peripheral surface 24a is slidably in contact with the offset through holes 16a, 18a, 20a of the outer gears 16, 18, 20 and the inner peripheral surface 24b is slidable with the outer peripheral surface 22a of the inner pin 22. It is in contact with possible.

The first carrier member 26 is arranged on one side in the axial direction (right side in FIG. 1) of the external gears 16, 18, and 20. The first carrier member 26 is fastened to the inner pin 22 by a bolt 30. The second carrier member 28 is arranged on the other side (left side in FIG. 1) of the external gears 16, 18, and 20 in the axial direction. In the present embodiment, the second carrier member 28 is formed integrally with the inner pin 22. Therefore, the first carrier member 26 and the second carrier member 28 are connected via the inner pin 22.

A bearing 32 is arranged between the first carrier member 26 and the input shaft 2, and a bearing 34 is arranged between the second carrier member 28 and the input shaft 2. The first carrier member 26 and the second carrier member 28 rotatably support the input shaft 2 via bearings 32 and 34.

The casing 36 is a substantially cylindrical member and surrounds the external gears 16, 18, 20, the first carrier member 26, and the second carrier member 28. A main bearing 38 is arranged between the casing 36 and the second carrier member 28. The casing 36 and the second carrier member 28 are configured to be relatively rotatable via the main bearing 38.

The internal gear 40 is formed on the inner peripheral surface of the casing 36. The internal gear 40 internally meshes with the external gears 16, 18, and 20. The internal gear 40 is configured by fitting cylindrical outer pins into pin grooves formed on the inner peripheral surface of the casing 36 at equal intervals. The internal gear 40 may be integrally formed on the inner peripheral surface of the casing 36. The number of internal teeth of the internal gear 40 is slightly (for example, only 1) larger than the number of external teeth of the external gears 16, 18, and 20.

An oil seal 82 is provided between the casing 36 and the second carrier member 28. As a result, the inside of the speed reducer 100 is sealed, and leakage of the lubricant in the speed reducer 100 is prevented.

2 (a) to 2 (c) are enlarged cross-sectional views showing the main bearing 38. FIG. 2A is a cross-sectional view in which the display of the tapered roller 46 is omitted, FIG. 2B is a cross-sectional view including the first tapered roller, and FIG. 2C is a cross-sectional view including the second tapered roller. It is a figure. See FIG. 2 in addition to FIG.

The main bearing 38 includes an outer ring 42, an inner ring 44, and a plurality of tapered rollers 46. The outer ring 42 is fixed to the inner peripheral surface of the casing 36. The outer ring 42 has rolling surfaces 42a and 42b provided on the inner peripheral surface so as to surround the rotation shaft R. The rolling surface 42a is located on the first carrier member side (right side in FIG. 2) in the axial direction, and the rolling surface 42b is located on the second carrier member side (left side in FIG. 2) in the axial direction. The rolling surface 42a and the rolling surface 42b form an annular V-groove that surrounds the rotation axis R.

The inner ring 44 is fixed to the outer peripheral surface of the second carrier member 28. The inner ring 44 has rolling surfaces 44a and 44b provided on the outer peripheral surface so as to surround the rotation shaft R. The rolling surface 44a is located on the first carrier member side in the axial direction, and the rolling surface 44b is located on the second carrier member side in the axial direction. The rolling surface 44a and the rolling surface 44b form an annular V-groove that surrounds the rotation axis R.

The rolling surface 42a and the rolling surface 44b are configured to approach each other toward the rolling surface 44a on a plane including the rotation axis R. The rolling surface 42a and the rolling surface 44b are such that the extension line L1 of the rolling surface 42a and the extension line L2 of the rolling surface 44b intersect on or near the rotation axis R, particularly on a plane including the rotation axis R. It is formed. Hereinafter, the intersection of the extension line L1 and the extension line L2 will be referred to as a first intersection P1.

The rolling surface 42b and the rolling surface 44a are configured to approach each other toward the rolling surface 44b on a plane including the rotation axis R. The rolling surface 42b and the rolling surface 44a are such that the extension line L3 of the rolling surface 42b and the extension line L4 of the rolling surface 44a intersect on or near the rotation axis R, particularly on a plane including the rotation axis R. It is formed. Hereinafter, the intersection of the extension line L3 and the extension line L4 will be referred to as a second intersection P2.

Further, with respect to the axial position, at least a part of the meshing position between the internal gear 40 and the external gears 16, 18 and 20 is configured to be located between the first intersection P1 and the second intersection P2. Will be done. Preferably, as shown in FIG. 1, the outer ring 42 and the inner ring 44 have the entire meshing position of the inner gear 40 and the outer gears 16, 18 and 20 in the axial position with respect to the first intersection P1. It is configured to be located between the second intersection P2.

Further, with respect to the axial position, at least a part, preferably all of the contact positions between the external gears 16, 18, 20 and the inner roller 24 are located between the first intersection P1 and the second intersection P2. It is configured to do.

Further, in the present embodiment, the bearings 32, 34 and the oil seal 82 are configured to be located between the first intersection P1 and the second intersection P2 in the axial position.

Each of the plurality of tapered rollers 46 has a substantially truncated cone shape. The plurality of tapered rollers 46 are arranged between the rolling surfaces 42a, 42b, 44a, 44b. Specifically, as shown in FIG. 2B, the plurality of tapered rollers 46 have a tapered roller 46 (hereinafter, "" The tapered roller 46 (hereinafter referred to as the "second tapered roller") in which the upper bottom side end surface 46a faces the rolling surface 44b of the inner ring 44 as shown in FIG. 2C. , Are arranged so as to be alternately arranged in the circumferential direction between the rolling surfaces 42a, 42b, 44a, 44b. The first tapered roller rolls on the rolling surface 42a and the rolling surface 44b, and the second tapered roller rolls on the rolling surface 42b and the rolling surface 44a of the inner ring 44.

The operation of the speed reducer 100 configured as described above will be described. Here, a case where the difference in the number of teeth between the external gears 16, 18 and 20 and the internal gear 40 is 1 will be described as an example.

When the input shaft 2 rotates, the eccentric bodies 4, 6 and 8 formed integrally with the input shaft 2 rotate, and the external gears 16, 18 and 20 swing via the rollers 10, 12 and 14. Due to this swing, a phenomenon occurs in which the meshing positions of the external gears 16, 18, 20 and the internal gear 40 are sequentially displaced.

Since the number of teeth of the external gears 16, 18 and 20 is one less than the number of teeth of the internal gear 40, the external gears 16, 18 and 20 have one tooth each time the input shaft 2 rotates once. The phase is shifted (rotated) with respect to the internal gear 40 by a minute (that is, a portion corresponding to the difference in the number of teeth). This rotation component comprises sliding the offset through holes 16a, 18a, 20a of the external gears 16, 18 and 20 with the inner roller 24, and the inner peripheral surface 24b of the inner roller 24 and the outer peripheral surface 22a of the inner pin 22. The second carrier member 28, which is transmitted to the inner pin 22 via sliding and is integrally formed with the inner pin 22, is reduced to 1 / (the number of teeth of the internal gear) with respect to the casing 36. Relative rotation. Therefore, when the casing 36 is fixed, the second carrier member 28 rotates, and when the second carrier member 28 is fixed, the casing 36 rotates.

According to the reduction gear 100 according to the first embodiment described above, the main bearing 38 has a truncated cone shape with the tapered roller 46, unlike the conventional cross roller bearing. In this case, the taper roller 46 moves while rolling between the outer ring 42 and the inner ring 44. Therefore, even if an internal preload is applied to the main bearing 38, there is no problem that the rotational torque is dramatically increased and the life is significantly shortened due to slippage. Therefore, an internal preload can be applied to the main bearing 38, and the moment rigidity can be increased. That is, it is possible to realize the reduction gear 100 which is small in size but has high moment rigidity of the main bearing.

Further, according to the reduction gear 100, at least a part of the meshing portion between the internal gear 40 and the external gears 16, 18 and 20 is located between the first intersection P1 and the second intersection P2 in the axial position. do. Further, regarding the axial position, at least a part of the contact position between the external gears 16, 18, 20 and the inner roller 24 is located between the first intersection P1 and the second intersection P2. Here, the first intersection P1 and the second intersection P2 are the points of action of the moment load, and the output extraction portion that is greatly affected by the moment load is located between them in the axial direction. The influence of the moment load on the meshing can be minimized.

Further, according to the speed reducing device 100, the bearings 32 and 34 are located between the first intersection P1 and the second intersection P2 in the axial position. Further, regarding the axial position, the oil seal 82 is located between the first intersection P1 and the second intersection P2. As a result, the influence of the moment load on the bearings 32 and 34 and the oil seal 82 can be minimized.

(Second Embodiment)
FIG. 3 is a cross-sectional view showing a speed reducing device 200 according to the second embodiment. The speed reducer 200 is a distribution type eccentric swing type speed reducer.

The speed reducer 200 includes an input shaft 102, eccentric bodies 104 and 106, rollers 110 and 112, external gears 116 and 118, a first carrier member 126, a second carrier member 128, a casing 136, and a main body. A bearing 138, an internal gear 140, an eccentric shaft gear 150, and an eccentric shaft 152 are provided.

A plurality (for example, three) of eccentric body shafts 152 are provided around the rotation shaft R of the speed reducing device 200 (internal gear 140) at equal intervals. Each eccentric body axis 152 is arranged parallel to the input axis 102.

The input shaft 102 is connected to a rotation drive source such as a motor, and rotates about the rotation shaft R. An input pinion 102a is formed at the tip of the input shaft 102, and the same number of eccentric shaft gears 150 as the eccentric shaft 152 mesh with the input pinion 102a. Each of the plurality of eccentric shaft gears 150 is spline-coupled to a spline 152a formed at the end of the corresponding eccentric shaft 152, and axial movement is restricted by a retaining ring (not shown).

The eccentric body shaft 152 is integrally formed with the eccentric body shaft 152 and two eccentric bodies 104 and 106 whose axes are deviated from each other. The two eccentric bodies 104 and 106 are eccentric with a phase difference of 180 degrees from each other. A plurality of (for example, three) eccentric body axes 152 are assembled so that the eccentric directions of the eccentric bodies 104 and 106 coincide with each other. The eccentric bodies 104 and 106 may be formed separately from the eccentric body shaft 152 and then fixed to the eccentric body shaft 152 by a key or the like.

Two external gears 116 and 118 are swingably fitted on the outer circumferences of the eccentric bodies 104 and 106 via rollers 110 and 112, respectively. The external tooth gears 116 and 118 are formed with a plurality of first through holes 116a and 118a and a plurality of second through holes 116b and 118b at positions offset from the axial center, respectively. The plurality of first through holes 116a and 118a are formed at equal intervals in the circumferential direction, and the eccentric body shaft 152 penetrates therethrough. The second through holes 116b and 118b are formed at equal intervals in the circumferential direction, and the convex portions 128a (described later) of the second carrier member 128 penetrate.

The first carrier member 126 has a substantially disk shape and is arranged on one side (right side in FIG. 3) of the external gears 116 and 118 in the axial direction. The second carrier member 128 is arranged on the other side (left side in FIG. 3) of the external gears 116 and 118 in the axial direction.

The second carrier member 128 is inserted through the second through holes 116b and 118b of the external gears 116 and 118 with a gap, and a plurality of convex portions extending in the axial direction toward the first carrier member 126 side (a plurality of convex portions ( Pillar portions) 128a are provided at equal intervals in the circumferential direction. The tip ends of the convex portion 128a of the first carrier member 126 and the second carrier member 128 are fastened by bolts 130. As a result, the first carrier member 126 and the second carrier member 128 rotate integrally.

The bearing 132 is arranged between the first carrier member 126 and the eccentric body shaft 152, and the bearing 134 is arranged between the second carrier member 128 and the input shaft 2. The first carrier member 126 and the second carrier member 128 rotatably support the eccentric body shaft 152 via bearings 132 and 134.

The casing 136 is a substantially cylindrical member, and surrounds the external gears 116 and 118, the first carrier member 126, and the second carrier member 128. A main bearing 138 is arranged between the casing 136 and the second carrier member 128. The casing 36 and the second carrier member 128 are configured to be relatively rotatable via the main bearing 138.

The internal gear 140 is formed on the inner peripheral surface of the casing 136. The internal gear 140 internally meshes with the external gears 116 and 118. The internal gear 140 is configured by fitting cylindrical outer pins into pin grooves formed on the inner peripheral surface of the casing 136 at equal intervals. The internal gear 140 may be integrally formed on the inner peripheral surface of the casing 136. The number of internal teeth of the internal gear 140 is slightly (for example, only 1) larger than the number of external teeth of the external gears 116 and 118.

An oil seal 182 is provided between the casing 136 and the second carrier member 128, and an oil seal 184 is provided between the second carrier member 128 and the input shaft 102. As a result, the inside of the speed reducer 200 is sealed, and the leakage of the lubricant in the speed reducer 200 is suppressed.

The main bearing 138 includes an outer ring 142, an inner ring 144, and a plurality of tapered rollers 146. The outer ring 142, the inner ring 144, and the tapered roller 146 are configured in the same manner as the outer ring 42, the inner ring 44, and the tapered roller 46, respectively.

In the present embodiment, with respect to the axial position, at least a part of the meshing positions of the internal gear 140 and the external gears 116 and 118, preferably all of the meshing positions, are the first intersection P1 and the second intersection P2. It is configured to be located between and. Further, regarding the axial position, at least a part, preferably all of the contact positions between the external gear 116 and the convex portion 128a of the second carrier member 128 are between the first intersection P1 and the second intersection P2. Configured to be located. Further, regarding the axial position, at least a part of the meshing position between the input shaft 102 of the input shaft 102 and the eccentric shaft gear 150, preferably the entire meshing position, is between the first intersection P1 and the second intersection P2. It is configured to be located in. Further, the outer ring 142 and the inner ring 144 are formed so that the bearings 132 and 134 and the oil seals 182 and 184 are located between the first intersection P1 and the second intersection P2 in the axial position.

The operation of the speed reducer 200 configured as described above will be described. Here, a case where the difference in the number of teeth between the external gears 116 and 118 and the internal gear 140 is 1 will be described as an example.

When the input shaft 102 rotates, the plurality of eccentric body shaft gears 150 meshing with the input pinion 102a of the input shaft 102 rotate (rotate), and the eccentric body shafts connected to each of the plurality of eccentric body shaft gears 150. 152 rotates (rotates).

When the eccentric body shaft 152 rotates, the eccentric bodies 104 and 106 formed integrally with the input shaft 2 rotate, and the external gears 116 and 118 swing via the rollers 110 and 112. Due to this swing, a phenomenon occurs in which the meshing positions of the external gears 116 and 118 and the internal gear 140 are sequentially displaced.

Since the number of teeth of the external gears 116 and 118 is one less than the number of teeth of the internal gear 140, the external gears 116 and 118 have one tooth (that is, one tooth) for each rotation of the eccentric body shaft 152. The phase is shifted (rotated) with respect to the internal gear 140 by the amount corresponding to the difference in the number of teeth. As a result, the eccentric body shaft 152 revolves around the rotation shaft R, and the first carrier member 126 and the second carrier member 128 supporting the eccentric body shaft 152 rotate relative to the casing 136. Therefore, when the casing 136 is fixed, the second carrier member 128 rotates, and when the second carrier member 128 is fixed, the casing 136 rotates.

According to the speed reducing device 200 according to the second embodiment described above, the internal preload can be applied to the main bearing 138 and the moment rigidity is increased as in the speed reducing device 100 according to the first embodiment. Can be done. That is, it is possible to realize a reduction gear 200 which is small in size but has high moment rigidity of the main bearing.

Further, according to the speed reducer 200, similarly to the speed reducer 100 according to the first embodiment, the output is greatly affected by the moment load between the first intersection P1 and the second intersection P2 with respect to the axial position. By locating the take-out portion of, the influence of the moment load on the meshing can be minimized.

Further, according to the speed reducer 200, similarly to the speed reducer 100 according to the first embodiment, the bearing and the oil seal are positioned between the first intersection P1 and the second intersection P2 in the axial position. By setting, the influence of the moment load on these can be minimized.

(Third Embodiment)
FIG. 4 is a cross-sectional view showing a speed reducing device 300 according to a third embodiment. The speed reducing device 300 is a flat type flexible meshing type speed reducing device.

The reduction gear 300 includes a wave generator 260, an external gear 216, an internal gear 240, a carrier member 226, a casing 236, a main bearing 238, a first bearing housing 272, and a second bearing housing 274. , Equipped with.

The wave generator 260 includes an input shaft 202, a plurality of first rolling elements 262a, a plurality of second rolling elements 262b, a first cage 264a, a second cage 264b, a first outer ring member 266a, and the like. Includes a second outer ring member 266b. The input shaft 202 is connected to a rotation drive source such as a motor, and rotates about the rotation shaft R of the reduction gear 300 (internal gear 240). A vibrator 202a having a substantially elliptical cross section orthogonal to the rotation axis R is integrally formed on the input shaft 202.

Each of the plurality of first rolling elements 262a has a substantially cylindrical shape, and is provided at intervals in the circumferential direction in a state in which the axial direction is oriented substantially parallel to the rotation axis R direction. The first rolling element 262a is rotatably held by the first cage 264a and rolls on the outer peripheral surface 202b of the oscillating body 202a. The second rolling element 262b is configured in the same manner as the first rolling element 262a. The plurality of second rolling elements 262b are rotatably held by the second cage 264b arranged so as to be aligned with the first cage 264a in the axial direction, and roll on the outer peripheral surface 202b of the oscillating body 202a. Hereinafter, the first rolling element 262a and the second rolling element 262b are collectively referred to as a “rolling body 262”. Further, the first cage 264a and the second cage 264b are collectively referred to as "retainer 264".

The first outer ring member 266a surrounds a plurality of first rolling elements 262a. The first outer ring member 266a has flexibility and is elliptically bent by the oscillating body 202a via the plurality of first rolling elements 262a. When the exciter 202a (that is, the input shaft 202) rotates, the first outer ring member 266a is continuously deformed according to the shape of the exciter 202a. The second outer ring member 266b is configured in the same manner as the first outer ring member 266a. The second outer ring member 266b is formed as a separate body from the first outer ring member 266a. The second outer ring member 266b may be integrally formed with the first outer ring member 266a. Hereinafter, the first outer ring member 266a and the second outer ring member 266b are collectively referred to as "outer ring member 266".

The external tooth gear 216 is a flexible annular member, and a vibrating body 202a, a rolling element 262, and an outer ring member 266 are fitted inside the external gear 216. As a result, the external gear 216 is bent in an elliptical shape. When the oscillating body 202a rotates, the external tooth gear 216 is continuously deformed according to the shape of the oscillating body 202a. The external tooth gear 216 includes a first external tooth portion 216a, a second external tooth portion 216b, and a base material 216c. The first external tooth portion 216a and the second external tooth portion 216b are formed on a base material 216c which is a single base material, and have the same number of teeth.

The internal gear 240 is an annular member having rigidity. The first internal tooth portion 240a of the internal tooth gear 240 surrounds the first external tooth portion 216a of the external tooth gear 216 bent in an elliptical shape, and is the first in a predetermined region near the long axis of the exciter 202a. It meshes with the external tooth portion 216a. The first internal tooth portion 240a has more teeth than the first external tooth portion 216a.

The carrier member 226 is a rigid cylindrical member. In the present embodiment, the second internal tooth portion 226a is formed on the inner peripheral surface of the carrier member 226. The second internal tooth portion 226a of the carrier member 226 surrounds the second external tooth portion 216b of the external tooth gear 216 bent in an elliptical shape, and the second outer tooth portion is formed in two regions in the major axis direction of the exciter 202a. It meshes with the tooth portion 216b. The second internal tooth portion 226a has the same number of teeth as the second external tooth portion 216b. Therefore, the carrier member 226 rotates in synchronization with the rotation of the second external tooth portion 216b and thus the external tooth gear 216.

The casing 236 is a substantially cylindrical member and surrounds the carrier member 226. The internal gear 240 is connected and integrated with the casing 236 by inlay fitting. The casing 236 and the carrier member 226 are configured to be relatively rotatable via the main bearing 238.

The first bearing housing 272 is an annular member and surrounds the input shaft 202. Similarly, the second bearing housing 274 is an annular member and surrounds the input shaft 202. The first bearing housing 272 and the second bearing housing 274 are arranged so as to sandwich the external gear 216 and the internal gear 240 in the axial direction. The first bearing housing 272 is connected to the internal gear 240 by inlay fitting. The second bearing housing 274 is connected to the carrier member 226 by inlay fitting.

The bearing 232 is incorporated in the first bearing housing 272, and the bearing 234 is incorporated in the second bearing housing 274. The first bearing housing 272 and the second bearing housing 274 rotatably support the input shaft 202 via the bearings 232 and 234.

An oil seal 282 is arranged between the input shaft 202 and the first bearing housing 272, an oil seal 284 is arranged between the casing 236 and the carrier member 226, and between the second bearing housing 274 and the input shaft 202. An oil seal 286 is arranged in the housing. Further, an O-ring 288 is arranged between the first bearing housing 272 and the internal gear 240, an O-ring 290 is arranged between the internal gear 240 and the casing 236, and the carrier member 226 and the second bearing housing are arranged. An O-ring 292 is arranged between the 274 and the O-ring 292. As a result, it is possible to prevent the lubricant in the speed reducer 300 from leaking.

The main bearing 238 includes an outer ring 242, an inner ring 244, and a plurality of tapered rollers 246. In the present embodiment, the outer ring 242 is integrally formed with the casing 236 on the inner peripheral surface side of the casing 236, and the inner ring 244 is integrally formed with the carrier member 226 on the outer peripheral surface of the carrier member 226. The outer ring 242, the inner ring 244, and the tapered roller 246 are configured in the same manner as the outer ring 42, the inner ring 44, and the tapered roller 46, respectively.

In the present embodiment, with respect to the axial position, at least a part of the meshing position between the first internal tooth portion 240a of the internal gear 240 and the second internal tooth portion 226a of the carrier member 226 and the external gear 216 is preferable. Is configured so that all of the meshing positions are located between the first intersection P1 and the second intersection P2. Further, with respect to the axial position, the bearings 232, 234 and the oil seals 282, 284, 286 are configured to be located between the first intersection P1 and the second intersection P2.

The operation of the speed reducer 300 configured as described above will be described. Here, the number of teeth of the first external tooth portion 216a is 100, the number of teeth of the second external tooth portion 216b is 100, the number of teeth of the first internal tooth portion 240a is 102, and the number of teeth of the second internal tooth portion 226a is 100. The case of is described as an example. Further, a case where the internal gear 240 and the first bearing housing 272 are in a fixed state will be described as an example.

When the input shaft 202 rotates while the first external tooth portion 216a is in mesh with the first internal tooth portion 240a at two points in the elliptical shape in the long axis direction, the first external tooth portion 216a and the first external tooth portion 216a and the first The meshing position with the internal tooth portion 240a also moves in the circumferential direction. Since the number of teeth is different between the first external tooth portion 216a and the first internal tooth portion 240a, at this time, the first external tooth portion 216a rotates relative to the first internal tooth portion 240a. Since the internal gear 240 and the first bearing housing 272 are in the fixed state, the first external tooth portion 216a rotates by the amount corresponding to the difference in the number of teeth. That is, the rotation of the input shaft 202 is significantly decelerated and output to the first external tooth portion 216a. The reduction ratio is as follows.
Reduction ratio = (number of teeth of the first external tooth portion 216a-number of teeth of the first internal tooth portion 240a) / number of teeth of the first external tooth portion 216a = (100-102) / 100
= -1/50

Since the second external tooth portion 216b is integrally formed with the first external tooth portion 216a, the second external tooth portion 216b rotates integrally with the first external tooth portion 216a. Since the second external tooth portion 216b and the second internal tooth portion 226a have the same number of teeth, relative rotation does not occur, and the second external tooth portion 216b and the second internal tooth portion 8a rotate integrally. Therefore, the same rotation as the rotation of the first external tooth portion 216a is output to the second internal tooth portion 226a, that is, the carrier member 226. As a result, the output obtained by reducing the rotation of the input shaft 202 to -1/50 can be taken out from the carrier member 226.

According to the speed reducing device 300 according to the third embodiment described above, the internal preload can be applied to the main bearing 238 and the moment rigidity is increased as in the speed reducing device 100 according to the first embodiment. Can be done. That is, it is possible to realize a reduction gear 300 which is small in size but has high moment rigidity of the main bearing.

Further, according to the speed reducer 300, similarly to the speed reducer 100 according to the first embodiment, the output is greatly affected by the moment load between the first intersection P1 and the second intersection P2 with respect to the axial position. By locating the take-out portion of, the influence of the moment load on the meshing can be minimized.

Further, according to the speed reducer 300, similarly to the speed reducer 100 according to the first embodiment, a bearing, an oil seal, or an O-ring is provided between the first intersection P1 and the second intersection P2 in the axial position. By positioning them, the influence of the moment load on them can be minimized.

(Fourth Embodiment)
FIG. 5 is a cross-sectional view showing a speed reducing device 400 according to a fourth embodiment. The speed reducing device 400 is a top hat type bending mesh speed reducing device.

The reduction gear 400 includes a wave generator 360, an external gear 316, an internal gear 340, a carrier member 326, a casing 336, a main bearing 338, a first bearing housing 372, and a second bearing housing 374. , Equipped with.

The wave generator 360 includes an input shaft 302, an inner ring member 368, a plurality of rolling elements 362, and an outer ring member 366. The input shaft 302 is connected to a rotary drive source such as a motor, and rotates about the rotary shaft R of the speed reducer 400 (internal gear 340). A vibrator 302a having a substantially elliptical cross section orthogonal to the rotation axis R is integrally formed on the input shaft 302.

The inner ring member 368 is an annular member and fits externally on the exciter 302a. The inner ring member 368 is particularly fixed to the oscillating body 302a by adhesion or press fitting, and rotates integrally with the oscillating body 302a. The outer peripheral surface 368a of the inner ring member 368 functions as a rolling surface on which the rolling element 362 rolls. The inner ring member 368 may be formed integrally with the oscillator 302a.

Each of the plurality of rolling elements 362 has a substantially spherical shape, and is provided at intervals in the circumferential direction. The rolling element 362 is rotatably held by a cage (not shown).

The outer ring member 366 surrounds a plurality of rolling elements 362. The outer ring member 366 has flexibility and is elliptically bent by the oscillating body 302a via the plurality of rolling elements 362. When the exciter 302a (that is, the input shaft 302) rotates, the outer ring member 366 is continuously deformed according to the shape of the exciter 302a.

The external tooth gear 316 is a flexible top hat-shaped member, and is provided on the outer periphery of a cylindrical body portion 316d and one side in the axial direction (right side in FIG. 5) of the body portion 316d. And the overhanging portion 316e protruding radially outward from the end portion of the body portion 316d on the other end side in the axial direction (left side in FIG. 5). The oscillator 302a, the rolling element 362, and the outer ring member 366 are fitted to the body portion 316d. As a result, the body portion 316d and the external tooth portion 316a are bent in an elliptical shape. When the exciter 302a rotates, the body portion 316d and the external tooth portion 316a are continuously deformed according to the shape of the exciter 302a.

The internal gear 340 is an annular member having rigidity. The internal tooth portion 340a of the internal tooth gear 340 surrounds the external tooth portion 316a of the external tooth gear 316 bent in an elliptical shape, and meshes with the external tooth portion 316a in a predetermined region near the long axis of the exciter 302a. .. The internal tooth portion 340a has more teeth than the external tooth portion 316a.

The casing 336 is a substantially cylindrical member, and surrounds the other side of the body portion 316d of the external gear 316 in the axial direction. Internal gears 340 are connected and integrated with the casing 336 by inlay fitting.

The carrier member 326 is a rigid cylindrical member that surrounds the casing 336. The carrier member 326 is fixed to the overhanging portion 316e of the external gear 316 together with the second bearing housing 374 by a bolt (not shown). Therefore, the carrier member 326 rotates in synchronization with the rotation with the external gear 316.

The casing 336 and the carrier member 326 are configured to be relatively rotatable via the main bearing 338.

The first bearing housing 372 is an annular member and surrounds the input shaft 302. Similarly, the second bearing housing 374 is an annular member that surrounds the input shaft 302. The first bearing housing 372 and the second bearing housing 374 are arranged so as to sandwich the external gear 316 and the internal gear 340 in the axial direction. The first bearing housing 372 is connected to the internal gear 340 by inlay fitting. Further, the second bearing housing 374 is fixed to the overhanging portion 316e of the external gear 316 by a bolt (not shown) as described above.

A bearing 332 is incorporated in the first bearing housing 372, and a bearing 334 is incorporated in the second bearing housing 374. The first bearing housing 372 and the second bearing housing 374 rotatably support the input shaft 302 via the bearings 332 and 334.

An oil seal 382 is arranged between the input shaft 302 and the first bearing housing 372, an oil seal 384 is arranged between the carrier member 326 and the casing 336, and between the second bearing housing 374 and the input shaft 302. An oil seal 386 is arranged in the housing. As a result, it is possible to prevent the lubricant in the speed reducer 400 from leaking.

The main bearing 338 includes an outer ring 342, an inner ring 344, and a plurality of tapered rollers 346. In the present embodiment, the outer ring 342 is integrally formed with the carrier member 326 on the inner peripheral surface side of the carrier member 326, and the inner ring 344 is integrally formed with the casing 336 on the outer peripheral side of the casing 336. The outer ring 342, the inner ring 344, and the tapered roller 346 are configured in the same manner as the outer ring 42, the inner ring 44, and the tapered roller 46, respectively.

In the present embodiment, the outer ring 342 and the inner ring 344 preferably have at least a part of the meshing position between the inner tooth portion 340a of the inner tooth gear 340 and the outer tooth portion 316a of the outer tooth gear 316 in the axial position. All of the meshing positions are formed so as to be located between the first intersection P1 and the second intersection P2. Further, the outer ring 342 and the inner ring 344 are formed so that the bearings 332, 334, the oil seals 382, 384, and 386 are located between the first intersection P1 and the second intersection P2 in the axial position.

The operation of the speed reducer 400 configured as described above will be described. Here, a case where the number of teeth of the external tooth portion 316a is 100 and the number of teeth of the internal tooth portion 340a is 102 will be described as an example. Further, a case where the internal gear 340 and the first bearing housing 372 are in a fixed state will be described as an example.

When the input shaft 302 rotates while the external tooth portion 316a is in mesh with the internal tooth portion 340a at two points in the elliptical long axis direction, the meshing position between the external tooth portion 316a and the internal tooth portion 340a is accompanied by this. Also moves in the circumferential direction. Since the number of teeth is different between the external tooth portion 316a and the internal tooth portion 340a, at this time, the external tooth portion 316a rotates relative to the internal tooth portion 340a. Since the internal gear 340 and the first bearing housing 372 are in the fixed state, the external tooth portion 316a and the external tooth gear 316 rotate by the amount corresponding to the difference in the number of teeth. Since the carrier member 326 is connected to the external gear 316, the same rotation as the rotation of the external gear 316 is output to the carrier member 326. As a result, the rotation of the input shaft 302 is significantly reduced from the carrier member 326 and output to the carrier member 326.

According to the speed reducing device 400 according to the fourth embodiment described above, the internal preload can be applied to the main bearing 338 and the moment rigidity is increased as in the speed reducing device 100 according to the first embodiment. Can be done. That is, it is possible to realize a reduction gear 300 which is small in size but has high moment rigidity of the main bearing.

Further, according to the speed reducer 400, similarly to the speed reducer 100 according to the first embodiment, the output is greatly affected by the moment load between the first intersection P1 and the second intersection P2 with respect to the axial position. By locating the take-out portion of, the influence of the moment load on the meshing can be minimized.

Further, according to the speed reducing device 400, similarly to the speed reducing device 100 according to the first embodiment, the bearing and the oil seal are positioned between the first intersection P1 and the second intersection P2 in the axial position. By setting, the influence of the moment load on these can be minimized.

The speed reduction device according to the embodiment has been described above. It will be appreciated by those skilled in the art that these embodiments are exemplary and that various modifications are possible for each of these components and combinations of processing processes, and that such modifications are also within the scope of the present invention. By the way. A modified example is shown below.

(Modification example 1)
In the third embodiment, there are two internal tooth portions (first internal tooth portion 240a and second internal tooth portion 226a), and the external gear 216 is a tubular flat type flexible meshing type deceleration. The device has been described. Further, in the fourth embodiment, a silk hat type flexible meshing type speed reducer having one internal tooth portion 340a and having a top hat type external gear 316 has been described. However, the technical idea of the first to fourth embodiments is not limited to this, and can be applied to a cup-type flexible meshing speed reducer having one internal gear and a cup-shaped external gear.

Further, although not particularly mentioned in the embodiment, the technical idea of the first to fourth embodiments can be applied to a reduction gear using a simple planetary gear mechanism.

Any combination of the embodiments and modifications described above is also useful as an embodiment of the present invention. The new embodiments resulting from the combination have the effects of the combined embodiments and variants.

It is also understood by those skilled in the art that the functions to be fulfilled by each of the constituent elements described in the claims are realized by a single component or a combination thereof shown in the embodiments and modifications. .. For example, the cam shaft and the cam bearing according to the claim may be realized by the input shaft 2 and the bearings 32, 34 in which the eccentric bodies 4, 6 and 8 according to the first embodiment are integrally formed. It may be realized by the eccentric body shaft 152 and the bearings 132, 134 integrally formed with the eccentric bodies 104 and 106 according to the second embodiment, and the oscillating body 202a according to the third embodiment is integrally formed. It may be realized by the input shaft 202 and the bearings 232 and 234 formed in the above, and may be realized by the input shaft 302 and the bearings 332 and 334 in which the exciter 302a according to the fourth embodiment is integrally formed. May be good.

Further, for example, the drive gear and the input gear according to the claim may be realized by the input pinion 102a and the eccentric body shaft gear 150 formed on the input shaft 102 of the second embodiment.

16, 18, 20 External gear, 36 Casing, 38 Main bearing, 40 Internal gear, 42 Outer ring, 42a, 42b Rolling surface, 44 Inner ring, 44a, 44b Rolling surface, 46 Tapered roller, 100 Reducer.

Claims (5)

The casing, the internal gear provided in the casing, the external gear that meshes with the internal gear, the carrier member that synchronizes with the rotation component or the revolution component of the external gear, and the casing and the carrier member. It is a reduction gear equipped with a main bearing arranged between the two.
The main bearing has an outer ring provided on one of the casing and the carrier member, an inner ring provided on the other of the casing and the carrier member, and a plurality of tapers arranged between the outer ring and the inner ring. With a roller,
In the plurality of tapered rollers, the first tapered roller and the second tapered roller that rolls on a rolling surface different from the first tapered roller are alternately arranged in the circumferential direction.
At least a part of the meshing portion between the internal gear and the external gear is an extension of the rolling surface of the first tapered roller in the outer ring and the rolling surface of the first tapered roller in the inner ring on the same plane. The first intersection, which is the intersection of the lines, and the second intersection, which is the intersection of the extension lines on the same plane of the rolling surface of the second tapered roller in the outer ring and the rolling surface of the second tapered roller in the inner ring. A speed reducer characterized by being located between. The reduction gear according to claim 1, wherein the entire meshing portion between the internal gear and the external gear is located between the first intersection and the second intersection. The reduction gear according to claim 1 or 2, wherein the cam bearing that supports the cam shaft that swings the external gear is located between the first intersection and the second intersection. The speed reduction device according to claim 3, wherein the meshing portion between the drive gear and the input gear provided on the cam shaft is located between the first intersection and the second intersection. The speed reduction device according to any one of claims 1 to 4, wherein an oil seal that seals the inside of the speed reduction device is located between the first intersection and the second intersection.

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