阅读说明：本技术 齿轮装置系列、齿轮装置系列的制造方法及设计方法 (Gear device series, method for manufacturing gear device series, and method for designing gear device series ) 是由 石塚正幸 南云稔也 吉田真司 于 2020-09-08 设计创作，主要内容包括：本发明以低成本提供具有所期望的性能的齿轮装置。齿轮装置系列包括第1齿轮装置(10)及第2齿轮装置(20)。第1齿轮装置(10)及第2齿轮装置(20)均为挠曲啮合式齿轮装置,所述挠曲啮合式齿轮装置具有内齿轮、外齿轮、使外齿轮挠曲变形的起振体及配置在外齿轮与起振体之间的起振体轴承。在第1齿轮装置(10)及第2齿轮装置(20)中,至少内齿轮构成为彼此相同的形状,而第1齿轮装置(10)中的外齿轮(11)和起振体轴承(12)的外圈(12a)之间的过盈量(δ1)与第2齿轮装置(20)中的外齿轮(21)和起振体轴承(22)的外圈(22a)之间的过盈量(δ2)则互不相同。(The present invention provides a gear device having desired performance at low cost. The gear train includes a 1 st gear (10) and a 2 nd gear (20). The 1 st gear device (10) and the 2 nd gear device (20) are both of a flex-mesh type gear device having an internal gear, an external gear, a vibration generator that causes the external gear to flex and deform, and a vibration generator bearing disposed between the external gear and the vibration generator. In the 1 st gear device (10) and the 2 nd gear device (20), at least internal gears are configured to have the same shape, and the interference (δ 1) between the external gear (11) and the outer ring (12a) of the oscillator bearing (12) in the 1 st gear device (10) and the interference (δ 2) between the external gear (21) and the outer ring (22a) of the oscillator bearing (22) in the 2 nd gear device (20) are different from each other.)

1. A gear train comprising a 1 st gear arrangement and a 2 nd gear arrangement, wherein,

the 1 st gear device and the 2 nd gear device are both of a flex-mesh type gear device having an internal gear, an external gear, a vibration generator that flexurally deforms the external gear, and a vibration generator bearing disposed between the external gear and the vibration generator,

in the 1 st gear device and the 2 nd gear device, at least the internal gears are formed in the same shape as each other, and interference between the external gear and the outer ring of the oscillator bearing is different from each other.

2. A gear train according to claim 1,

in the 1 st gear device and the 2 nd gear device, outer diameters of outer rings of the oscillator bearings are different from each other.

3. A gear unit series according to claim 2,

in the 1 st gear device and the 2 nd gear device, outer diameters of retainers of the oscillating element bearings are different from each other.

4. A gear unit series according to claim 2 or 3,

in the 1 st gear device and the 2 nd gear device, the outer circumferential lengths of the oscillator are different from each other.

5. A gear unit series according to any one of claims 2 to 4,

in the 1 st gear device and the 2 nd gear device, the rolling elements of the oscillator bearing are formed in the same shape.

6. A gear unit series according to any one of claims 1 to 5,

in the 1 st gear device and the 2 nd gear device, the amount of lubricant sealed inside is different from each other.

7. A method of manufacturing a gear train including a 1 st gear device and a 2 nd gear device, wherein,

the 1 st gear device and the 2 nd gear device are both of a flex-mesh type gear device having an internal gear, an external gear, a vibration generator that flexurally deforms the external gear, and a vibration generator bearing disposed between the external gear and the vibration generator,

in the 1 st gear device and the 2 nd gear device, at least the internal gears are configured to have the same shape,

the manufacturing method comprises:

a manufacturing process of the 1 st gear device, including a process of fitting the external gear of the 1 st gear device and an outer ring of the oscillator bearing with a 1 st interference; and

the 2 nd gear device manufacturing step includes a step of fitting the external gear of the 2 nd gear device and the outer ring of the oscillator bearing with a 2 nd interference different from the 1 st interference.

8. A method of designing a gear train comprising a 1 st gear and a 2 nd gear, wherein,

the 1 st gear device and the 2 nd gear device are both of a flex-mesh type gear device having an internal gear, an external gear, a vibration generator that flexurally deforms the external gear, and a vibration generator bearing disposed between the external gear and the vibration generator,

in the 1 st gear device and the 2 nd gear device, at least the internal gears are configured to have the same shape,

setting a 1 st interference between the external gear of the 1 st gear device and an outer ring of the oscillator bearing,

setting the external gear of the 2 nd gear unit and the outer ring of the oscillator bearing to a 2 nd interference amount different from the 1 st interference amount.

Technical Field

The present invention relates to a gear device series, a manufacturing method and a design method of the gear device series.

Background

Conventionally, a flexible mesh type gear device including an external gear that is flexible and deformable is known (for example, see patent document 1). The external gear has a vibration generator embedded therein via a vibration generator bearing, and the vibration generator rotates inside to be deformed. Also, the external gear meshes with the internal gear having rigidity.

As the performance of such a gear device, there is a spring constant representing the torsional rigidity of the power transmission system. In order to increase the spring constant, measures such as increasing the number of gears to be engaged and increasing the thickness of the ring gear of the external gear (the thickness between the tooth root and the inner periphery) are required. However, these measures increase power loss, resulting in a decrease in power transmission efficiency.

Therefore, in order to adjust the spring constant and the power transmission efficiency, which have such a trade-off relationship, to make these performances desirable, it is necessary to make a large part change such as changing the tooth profile even at the same reduction ratio, which leads to an increase in the product cost.

Patent document 1: japanese patent laid-open No. 2014-199130

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a gear device having desired performance at low cost.

The gear train according to the present invention includes a 1 st gear device and a 2 nd gear device, wherein,

the 1 st gear device and the 2 nd gear device are both of a flex-mesh type gear device having an internal gear, an external gear, a vibration generator that flexurally deforms the external gear, and a vibration generator bearing disposed between the external gear and the vibration generator,

in the 1 st gear device and the 2 nd gear device, at least the internal gears are formed in the same shape as each other, and interference between the external gear and the outer ring of the oscillator bearing is different from each other.

A method for manufacturing a gear train according to the present invention is a method for manufacturing a gear train including a 1 st gear device and a 2 nd gear device,

the 1 st gear device and the 2 nd gear device are both of a flex-mesh type gear device having an internal gear, an external gear, a vibration generator that flexurally deforms the external gear, and a vibration generator bearing disposed between the external gear and the vibration generator,

in the 1 st gear device and the 2 nd gear device, at least the internal gears are configured to have the same shape, and the manufacturing method includes:

a manufacturing process of the 1 st gear device, including a process of fitting the external gear of the 1 st gear device and an outer ring of the oscillator bearing with a 1 st interference; and

the 2 nd gear device manufacturing step includes a step of fitting the external gear of the 2 nd gear device and the outer ring of the oscillator bearing with a 2 nd interference different from the 1 st interference.

A method for designing a gear train according to the present invention is a method for designing a gear train including a 1 st gear device and a 2 nd gear device,

the 1 st gear device and the 2 nd gear device are both of a flex-mesh type gear device having an internal gear, an external gear, a vibration generator that flexurally deforms the external gear, and a vibration generator bearing disposed between the external gear and the vibration generator,

in the 1 st gear device and the 2 nd gear device, at least the internal gears are configured to have the same shape,

setting a 1 st interference between the external gear of the 1 st gear device and an outer ring of the oscillator bearing,

setting the external gear of the 2 nd gear unit and the outer ring of the oscillator bearing to a 2 nd interference amount different from the 1 st interference amount.

According to the present invention, a gear device having desired performance can be provided at low cost.

Drawings

Fig. 1 is a cross-sectional view showing a 1 st gear device according to the present embodiment.

Fig. 2 is a diagram for explaining a spring constant.

Fig. 3 is a cross-sectional view showing the 2 nd gear device according to the present embodiment.

Fig. 4 is a diagram for explaining interference between the external gear and the outer ring of the starting carrier bearing, in which (a) is a diagram showing interference of the 1 st gear device and (b) is a diagram showing interference of the 2 nd gear device.

In the figure: 10-gear 1, 11-external gear, d 11-inner diameter, δ 1-interference between external gear and external ring of oscillator bearing, 12-oscillator bearing, 12 a-external ring, d12 i-inner diameter, d12 o-outer diameter, 12 b-rolling element, 12 c-retainer, PCD 1-pitch diameter, 20-gear 2, 21-external gear, d 21-inner diameter, interference between δ 2-external gear and external ring of oscillator bearing, 22-oscillator bearing, 22 a-external ring, d22 i-inner diameter, d22 o-outer diameter, 22 b-rolling element, 22 c-retainer, 2-pitch diameter, 30-oscillator shaft, 30A-oscillator, 31G-internal gear 1, 32G-internal gear 2, o1-rotating shaft, S-sealed space.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The gear train according to the present embodiment is a product set of flexible mesh gear devices including the 1 st gear device 10 and the 2 nd gear device 20.

[ Structure of the 1 st Gear device ]

First, the structure of the 1 st gear device 10 according to the present embodiment will be described. Fig. 1 is a sectional view showing a 1 st gear device 10.

As shown in fig. 1, the 1 st gear device 10 includes a starting body shaft 30, an external gear 11, a 1 st internal gear 31G, a 2 nd internal gear 32G, a starting body bearing 12, a housing 33, a 1 st cover 34, and a 2 nd cover 35.

The oscillator shaft 30 is a hollow cylindrical shaft that rotates about the rotation axis O1, and has an oscillator 30A with a non-circular (for example, elliptical) outer shape in cross section perpendicular to the rotation axis O1, and shaft portions 30B and 30C provided on both sides of the oscillator 30A in the axial direction. The elliptical shape is not limited to an ellipse in a geometrically strict sense, but includes a substantially elliptical shape. The shaft portions 30B and 30C are shafts having circular outer shapes in cross section perpendicular to the rotation axis O1. The oscillation body shaft 30 is an input shaft that is connected to a drive source (not shown) such as a motor and that inputs a driving force.

In the following description, a direction along the rotation axis O1 is referred to as an "axial direction", a direction perpendicular to the rotation axis O1 is referred to as a "radial direction", and a rotation direction around the rotation axis O1 is referred to as a "circumferential direction". The side (left side in the drawing) that is coupled to the external target member in the axial direction and outputs the decelerated motion to the target member is referred to as an "output side", and the side (right side in the drawing) opposite to the output side is referred to as an "opposite output side". The inner diameter, outer diameter, and PCD of each component of the oscillating mass bearing and the external gear are: inner diameter and outer diameter before fitting with the oscillator, and PCD.

The external gear 11 is a cylindrical member having flexibility and centered on the rotation axis O1, and has teeth provided on the outer periphery thereof.

The 1 st ring gear 31G and the 2 nd ring gear 32G rotate around the start body shaft 30 around the rotation shaft O1. These 1 st internal gear 31G and 2 nd internal gear 32G are arranged in line in the axial direction and mesh with external gear 11. Specifically, one of the 1 st internal gear 31G and the 2 nd internal gear 32G meshes with the teeth of the external gear 11 on one side of the center in the axial direction, and the other meshes with the teeth of the external gear 11 on the other side of the center in the axial direction.

The 1 st internal gear 31G is formed by providing internal teeth at corresponding portions of the inner peripheral portion of the 1 st internal gear member 31. On the other hand, the 2 nd internal gear 32G is configured by providing internal teeth at corresponding portions of the inner peripheral portion of the 2 nd internal gear member 32.

The oscillator bearing 12 is, for example, a roller bearing, and is disposed between the oscillator 30A and the external gear 11. The oscillator 30A and the external gear 11 are rotatable relative to each other via the oscillator bearing 12.

The starting element bearing 12 includes an outer ring 12a fitted inside the external gear 11 with a predetermined interference δ 1, a plurality of rolling elements (rollers) 12b, and a cage 12c holding the plurality of rolling elements 12 b.

The interference δ 1 between the external gear 11 and the outer ring 12a can be obtained by changing δ 1 to (d12o-d11)/2 according to the inner diameter d11 of the external gear 11 and the outer diameter d12o of the outer ring 12a (see (a) in fig. 4). In the present embodiment, the interference δ 1 is a positive value (δ 1 > 0), and the external gear 11 and the outer ring 12a of the starting oscillator bearing 12 are press-fitted (interference fit). However, the "interference" according to the present invention includes a value equal to or smaller than zero (that is, a case where the external gear is in transition fit or clearance fit with the outer ring of the starting body bearing).

The plurality of rolling elements 12b include a 1 st group of rolling elements 12b arranged radially inward of the 1 st ring gear 31G and arranged in the circumferential direction, and a 2 nd group of rolling elements 12b arranged radially inward of the 2 nd ring gear 32G and arranged in the circumferential direction. These rolling elements 12b roll with the outer peripheral surface of the oscillator 30A and the inner peripheral surface of the outer ring 12a as rolling surfaces. The outer ring 12a is provided with two outer rings having the same shape and arranged in the axial direction in accordance with the arrangement of the plurality of rolling elements 12 b. The oscillator bearing 12 may have an inner ring separate from the oscillator 30A.

On both sides in the axial direction of the oscillator bearing 12 and the external gear 11, spacer rings 41 and 42 are provided as restricting members that abut against them and restrict their movement in the axial direction.

The outer case 33 covers the outer diameter side of the 2 nd internal gear 32G. The outer case 33 is coupled to the 1 st internal gear member 31 by a coupling member such as a bolt. The housing 33 has an outer ring portion of a main bearing 38 formed on an inner peripheral portion thereof, and the housing 33 rotatably supports the 2 nd internal gear member 32 via the main bearing 38.

The 1 st cover 34 is coupled to the 1 st internal gear member 31, and the 1 st cover 34 covers a meshing portion between the external gear 11 and the 1 st internal gear 31G on the side opposite to the output side in the axial direction.

A bearing 36 is disposed between the 1 st cover 34 and the shaft 30B of the start body shaft 30, and the 1 st cover 34 rotatably supports the start body shaft 30 via the bearing 36.

The 2 nd cover body 35 is coupled to the 2 nd internal gear member 32, and the 2 nd cover body 35 covers a meshing portion between the external gear wheel 11 and the 2 nd internal gear member 32G from the output side in the axial direction. The 2 nd cover 35 and the 2 nd internal gear member 32 are coupled to an external target member that outputs a decelerated motion.

A bearing 37 is disposed between the 2 nd cover 35 and the shaft portion 30C of the start body shaft 30, and the 2 nd cover 35 rotatably supports the start body shaft 30 via the bearing 37.

The 1 st gear device 10 further includes oil seals 43, 44, and 45 for sealing, and O-rings 46, 47, and 48.

The oil seal 43 is disposed between the shaft portion 30B of the oscillation body shaft 30 at the end portion on the opposite output side in the axial direction and the 1 st cover 34, and suppresses the lubricant from flowing out to the opposite output side. The oil seal 44 is disposed between the shaft portion 30C of the excitation shaft 30 on the output side end in the axial direction and the 2 nd cover 35, and suppresses the lubricant from flowing out to the output side. An oil seal 45 is disposed between the casing 33 and the 2 nd inner gear member 32, which suppresses the outflow of the lubricant from that portion.

The O-ring 46 is provided between the 1 st internal gear member 31 and the 1 st cover 34, the O-ring 47 is provided between the 1 st internal gear member 31 and the housing 33, and the O-ring 48 is provided between the 2 nd internal gear member 32 and the 2 nd cover 35, thereby suppressing the lubricant from flowing out therebetween.

That is, the lubricant is sealed in the sealed space S inside the 1 st gear device 10 sealed by the oil seals 43 to 45 and the O-rings 46 to 48. The lubricant used is not particularly limited, and lubricating oil or grease may be used.

[ deceleration operation of the first gear device ]

Next, the deceleration operation of the 1 st gear device 10 will be described.

When the starting body shaft 30 is rotated by driving of a driving source such as a motor, the motion of the starting body shaft 30A is transmitted to the external gear 11. At this time, the shape of the external gear 11 is restricted to conform to the outer peripheral surface of the oscillator 30A, whereby the external gear 11 is flexed into an elliptical shape having a major axis portion and a minor axis portion as viewed in the axial direction. Further, the external gear 11 meshes with the fixed 1 st internal gear 31G through the long shaft portion. Therefore, the external gear 11 does not rotate at the same rotational speed as the oscillator 30A, and the oscillator 30A rotates relatively inside the external gear 11. Then, the external gear 11 is formed so as to flex with the relative rotation so that the long axis position and the short axis position thereof move in the circumferential direction. The period of this deformation is proportional to the rotation period of the start-up body shaft 30.

When the external gear 11 is deformed, the long-axis position thereof moves, and therefore, the meshing position between the external gear 11 and the 1 st internal gear 31G changes in the rotational direction. Here, for example, when the number of teeth of the external gear 11 is 100 and the number of teeth of the 1 st internal gear 31G is 102, the meshing teeth of the external gear 11 and the 1 st internal gear 31G are shifted every rotation of the meshing position, and the external gear 11 rotates (rotates). When the number of teeth is set to the above number of teeth, the rotational motion of the start body shaft 30 is reduced in speed at a reduction ratio of 100:2 and then transmitted to the external gear 11.

On the other hand, since the external gear 11 is also meshed with the 2 nd internal gear 32G, the meshing position of the external gear 11 and the 2 nd internal gear 32G is also changed in the rotational direction by the rotation of the oscillation start shaft 30. Here, if the number of teeth of the 2 nd internal gear 32G is equal to the number of teeth of the external gear 11, the external gear 11 and the 2 nd internal gear 32G do not rotate relative to each other, and the rotational motion of the external gear 11 is transmitted to the 2 nd internal gear 32G at a reduction ratio of 1: 1. Thus, the rotational motion of the start body shaft 30 is reduced in speed at a reduction ratio of 100:2, transmitted to the 2 nd internal gear member 32 and the 2 nd cover 35, and then output to the target member.

Here, in the 1 st gear device 10, the interference δ 1 is a positive value (δ 1 > 0), and the external gear 11 and the outer ring 12a of the oscillator bearing 12 are press-fitted. Therefore, the rigidity of the external gear 11 and the outer ring 12a of the starting oscillator bearing 12 is high and the spring constant is large.

The spring constant is a performance parameter indicating the torsional rigidity of a power transmission system of a gear device (reduction gear). Fig. 2 is a diagram for explaining a spring constant. When the load is applied slowly from the output shaft (low speed shaft) side to the rated torque in a state where the input shaft (high speed shaft) of the reduction gear is fixed, and the load until the load is removed and the displacement (torsion angle) of the low speed shaft are measured and the relationship is shown, a rigid hysteresis curve (hysteresis curve) as shown in fig. 2 can be obtained. The spring constant is defined as a ratio of a difference between torques from a certain point (50% in the example of the figure) to 100% of the rated torque to a difference between torsion angles. In the 1 st and 2 nd gear devices 10 and 20 according to the present embodiment, the input shaft corresponds to the start body shaft 30, and the output shaft corresponds to the 2 nd cover 35 and the 2 nd internal gear member 32.

On the other hand, since the external gear 11 and the outer ring 12a of the starting oscillator bearing 12 are press-fitted, the external gear 11 and the outer ring 12a are more likely to be displaced in the circumferential direction during operation than when the interference δ 1 is smaller. If the external gear 11 and the outer ring 12a are displaced from each other, fretting wear is likely to occur if the mating portion is deficient in lubricating oil. Therefore, a sufficient amount of lubricant needs to be enclosed in the sealed space S so as not to cause fretting. As a result, the agitation loss of the lubricating oil during operation becomes relatively large and the power transmission efficiency is lowered, as compared with the case where the interference δ 1 is smaller.

[ Structure of the 2 nd Gear device ]

Next, the structure of the 2 nd gear device 20 according to the present embodiment will be described. Fig. 3 is a sectional view showing the 2 nd gear device 20.

As shown in fig. 3, the 2 nd gear device 20 includes an external gear 21 and a starting element bearing 22. In the 2 nd gear unit 20, the interference between the external gear 21 and the outer ring 22a of the oscillator bearing 22 is different from that of the 1 st gear unit 10, and the constituent elements that are not related to the interference (specifically, the constituent elements other than the external gear 21, the oscillator bearing 22, and the oscillator 30A) have the same configuration (the same shape and the same size) as those of the 1 st gear unit 10. Here, "the same (the same shape and size)" means that the shape and size are designed to be the same, allowing for slight differences due to manufacturing errors and the like. Hereinafter, description will be given mainly of points different from the 1 st gear device 10, and the same constituent elements as those of the 1 st gear device 10 are denoted by the same reference numerals and detailed description thereof is omitted.

The external gear wheel 21 is formed in the same shape as the external gear wheel 11 of the 1 st gear device 10.

That is, the external gear 21 is a cylindrical member having flexibility and centered on the rotation axis O1, and has teeth provided on the outer periphery thereof.

The oscillator bearing 22 has the same structure as the oscillator bearing 12 of the 1 st gear 10.

That is, the oscillator bearing 22 is, for example, a roller bearing, and is disposed between the oscillator 30A and the external gear 21. The oscillator 30A and the external gear 21 are relatively rotatable via the oscillator bearing 22.

The starting vibrator bearing 22 includes an outer ring 22a fitted inside the external gear 21 with interference δ 2 described later, a plurality of rolling elements (rollers) 22b, and a cage 22c holding the plurality of rolling elements 22 b. The plurality of rolling elements 22b include a 1 st group of rolling elements 22b arranged radially inward of the 1 st ring gear 31G and arranged in the circumferential direction, and a 2 nd group of rolling elements 22b arranged radially inward of the 2 nd ring gear 32G and arranged in the circumferential direction. These rolling elements 22b roll with the outer peripheral surface of the oscillator 30A and the inner peripheral surface of the outer ring 22a as rolling surfaces. The outer ring 22a is provided with two outer rings having the same shape and arranged in the axial direction in accordance with the arrangement of the plurality of rolling elements 22 b. The oscillator bearing 22 may have an inner ring separate from the oscillator 30A.

Regarding the external gear 21 and the starting vibrator bearing 22, the interference δ 2 between the external gear 21 and the outer ring 22a of the starting vibrator bearing 22 is different from the interference δ 1 of the 1 st gear device 10.

Fig. 4 is a diagram for explaining interference between the external gear and the outer ring of the starting carrier bearing, in which (a) is a diagram showing interference δ 1 of the 1 st gear device 10, and (b) is a diagram showing interference δ 2 of the 2 nd gear device 20. In fig. 4, for convenience of understanding, the interference δ 1 and the interference δ 2 are shown enlarged from the actual size.

As shown in fig. 4, the interference δ 2 can be obtained by changing δ 2 to (d22o-d21)/2, depending on the inner diameter d21 of the external gear 21 and the outer diameter d22o of the outer ring 22 a. The interference δ 2 of the present embodiment is smaller than the interference δ 1 of the 1 st gear device 10 and is a negative value. That is, the external gear 21 is fitted to the outer ring 22a of the starting oscillator bearing 22 with a clearance fit.

In the present embodiment, the inner diameter d21 of the external gear 21 is the same as the inner diameter d11 of the external gear 11 in the 1 st gear device 10, and the outer diameter d22o of the outer ring 22a of the starting body bearing 22 is different from the outer diameter d12o of the outer ring 12a of the starting body bearing 12 in the 1 st gear device 10. Specifically, the outer diameter d22o of the outer race 22a is smaller than the outer diameter d12o of the outer race 12a in the 1 st gear device 10. Thus, the interference δ 2 of the 2 nd gear device 20 becomes smaller than the interference δ 1 of the 1 st gear device 10.

As described above, the fitting portions between the outer diameter d22o of the outer ring 22a and the inner diameter d21 of the external gear 21 are displaced from each other during operation, and fretting occurs. Therefore, when the clearance fit with a small interference is adopted, it is preferable to form the outer diameter d22o of the outer ring 22a in a relationship (clearance relationship) with respect to the inner diameter d21 of the external gear 21, in which a shift of a predetermined curvature radius is unlikely to occur. This can suppress the occurrence of fretting wear in the fitting portion.

When the outer diameter d22o of the outer ring 22a is different from that of the 1 st gear device 10, the thickness t22 of the outer ring 22a is preferably set to be the same as the thickness t12 of the outer ring 12a in the 1 st gear device 10 from the viewpoint of stress acting on the outer ring 22a during operation. That is, the amount of change (reduction) in the inner diameter d22i of the outer race 22a relative to the inner diameter d12i of the outer race 12a in the 1 st gear device 10 is preferably made to be the same as the amount of change in the outer diameter d22o of the outer race 22a relative to the outer diameter d12o of the outer race 12a in the 1 st gear device 10. Further, since the stress increases as the thickness of the outer ring increases, it is preferable to avoid increasing the thickness of the outer ring, and therefore, if there is a room for reducing the thickness of the outer ring in terms of processing, strength, and the like, the thickness can be reduced.

Even when the inner diameter d22i of the outer race 22a is different from that of the 1 st gear device 10 in this way, the rolling elements 22b of the oscillator bearing 22 can be the same shape as the rolling elements 12b in the 1 st gear device 10.

However, the pitch circle diameter PCD2 of the starting element bearing 22 is changed from the pitch circle diameter PCD1 of the starting element bearing 12 in the 1 st gear device 10. Therefore, in response to this, it is necessary to use a retainer 22c of the starting element bearing 22 having a different (smaller) outer diameter and inner diameter than the retainer 12c of the starting element bearing 12 of the 1 st gear device 10. In response to the change in the pitch circle diameter, the outer circumference of the oscillator 30A of the 2 nd gear device 20, which is the inner ring of the oscillator bearing 22, needs to be different (smaller) from the outer circumference of the oscillator 30A of the 1 st gear device 10.

In addition, as for the external gear 21 and the starting vibrator bearing 22, the interference δ 2 between the external gear 21 and the outer ring 22a of the starting vibrator bearing 22 may be different from the interference δ 1 of the 1 st gear device 10. Therefore, the outer diameter d22o of the outer ring 22a of the starting element bearing 22 may be made the same as that in the 1 st gear device 10 and the inner diameter d21 of the external gear 21 may be made different from the inner diameter d11 of the external gear 11 in the 1 st gear device 10. However, if the ring thickness (i.e., the thickness between the tooth root and the inner periphery) of the external gear becomes thick, the stress acting on the external gear increases. Therefore, when the inner diameter of the external gear is reduced, it is preferable to control the inner diameter within a range that has no problem in strength.

Further, both the outer diameter d22o of the outer ring 22a of the starting vibrator bearing 22 and the inner diameter d21 of the external gear 21 may be different from the outer diameter and the inner diameter of the 1 st gear device 10. However, it is needless to say that the interference δ 2 needs to be different from the interference δ 1 of the 1 st gear device 10.

[ deceleration action of the 2 nd gear device ]

Next, the deceleration operation of the 2 nd gear device 20 will be described.

The 2 nd gear device 20 operates in the same manner as the 1 st gear device 10. That is, when the oscillation starting body shaft 30 is rotated by driving of a driving source such as a motor, the oscillation starting body 30A causes the external gear wheel 21 to be flexurally deformed. In this way, the external gear wheel 21 rotates with respect to the 1 st internal gear wheel 31G, but the external gear wheel 21 does not rotate with respect to the 2 nd internal gear wheel 32G, corresponding to the difference in the number of teeth between the 1 st internal gear wheel 31G and the 2 nd internal gear wheel 32G. Thereby, the rotational motion of the start body shaft 30 is decelerated and transmitted to the 2 nd internal gear member 32 and the 2 nd cover 35, and is output to the target member.

Here, in the 2 nd gear unit 20, the interference δ 2 is a negative value smaller than the interference δ 1 of the 1 st gear unit 10 (δ 2 < 0), and the external gear 21 and the outer ring 22a of the starting carrier bearing 22 are fitted in a clearance fit. Therefore, the rigidity of the external gear 21 and the outer ring 22a of the starting body bearing 22 is lower and the spring constant is smaller than that of the 1 st gear device 10.

On the other hand, since the interference δ 2 is smaller than the interference δ 1 of the 1 st gear device 10, the lubrication state of the lubricant in the fitting portion between the external gear 21 and the outer ring 22a of the starting oscillator bearing 22 is improved as compared with the 1 st gear device 10. In the present embodiment, the fitting portion is in clearance fit, and therefore the lubrication state is further improved here. Therefore, a smaller amount of lubricant may be sealed in the sealed space S than in the 1 st gear device 10. As described above, if the fitting portion capable of suppressing the occurrence of fretting wear is employed, the amount of the enclosed lubricant can be further reduced. As a result, the stirring loss of the lubricating oil during operation is relatively smaller than that of the 1 st gear device 10 having a larger interference δ 1, and the power transmission efficiency is improved.

[ technical effects of the present embodiment ]

As described above, according to the present embodiment, the interference δ 1 between the external gear 11 and the outer ring 12a of the starting body bearing 12 in the 1 st gear device 10 is different from the interference δ 2 between the external gear 21 and the outer ring 22a of the starting body bearing 22 in the 2 nd gear device 20.

That is, the spring constant and the power transmission efficiency can be adjusted by making the interference between the external gear and the outer ring of the starting oscillator bearing different in the 1 st gear device 10 and the 2 nd gear device 20. Specifically, although the power transmission efficiency is reduced by increasing the interference, the spring constant can be increased, and the power transmission efficiency can be improved by decreasing the interference while decreasing the spring constant.

Therefore, the spring constant and the power transmission efficiency can be set to desired spring constants and power transmission efficiencies by only the minimum component change relating to the interference without performing a significant component change such as changing the tooth profile. Further, a gear device having desired performance can be provided at low cost. Specifically, the 1 st gear device 10 can be provided for an application where the spring constant is important, and the 2 nd gear device 20 can be provided for an application where the power transmission efficiency is important.

[ others ]

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.

For example, in the above-described embodiment, the 1 st gear device 10 and the 2 nd gear device 20 are configured to have the same configuration (have the same shape and size) regardless of the interference between the external gear and the outer ring of the oscillator bearing. However, in the 1 st gear device 10 and the 2 nd gear device 20, at least the internal gears may have the same shape, and the shapes of the other components may be different from each other.

In the above embodiment, the interference δ 1 of the 1 st gear device 10 is a positive value, and the interference δ 2 of the 2 nd gear device 20 is a negative value. However, the interference δ 1 and the interference δ 2 may be different from each other.

In the above embodiment, a tubular type mesh gear device is exemplified as the 1 st gear device 10 and the 2 nd gear device 20. However, the flexible engagement gear device according to the present invention is not limited to the cylindrical type, and a cup type or a silk hat type gear device may be used.

The details shown in the above embodiments may be appropriately modified without departing from the spirit and scope of the invention.

In the above description, the present invention has been described from the viewpoint of a gear train (product group) including a plurality of gear devices, but from the viewpoint of how to construct or design each gear device included in the train, the present invention can also be regarded as a method of constructing or a method of designing the gear train (gear train group). In addition, the present invention can also be regarded as a method for manufacturing a gear train (gear train set) including a plurality of gear trains, from the viewpoint of how to manufacture the gear train (gear train set).