Eccentric oscillating gear device

Abstract

The invention provides an eccentric swing type gear device capable of enlarging a hollow part. The eccentric swinging type gear device (100) is provided with an internal gear (16), an external gear (14), an eccentric body enabling the external gear (14) to swing, a wheel carrier arranged on the side portion of the external gear (14) in the axial direction, and a plurality of inner pins (32) connected with the wheel carrier at the position offset from the center of the wheel carrier and penetrating through the external gear. The ratio of the pitch diameter (Dp) of the inner pin (32) to the addendum diameter (De) of the external gear (14) (pitch diameter (Dp) / addendum diameter (De)) is 0.77-0.85, the ratio of the diameter (Dq) of the inner pin (32) to the addendum diameter (De) of the external gear (14) (inner pin diameter (Dq) / addendum diameter (De)) is 0.06-0.10, and the proportion of the inner pin (32) on the pitch circumference of the inner pin (32) (i.e., the inner pin occupancy) is 0.25 or more.

Description

[0001] This application is a divisional application of the invention patent application with application number 202110168968.5, application date February 7, 2021, and invention name “Eccentric swing type gear device”.

[0002] This application claims priority based on Japanese Patent Application No. 2020-054601 filed on March 25, 2020. The entire contents of the Japanese Patent Application are incorporated herein by reference. Technical Field

[0003] The invention relates to an eccentric swing type gear device. Background Art

[0004] An eccentric oscillating speed reducer is known that reduces the speed of rotation input to an input shaft. The applicant disclosed an eccentric oscillating speed reducer having an external gear that oscillates due to the rotation of the input shaft and an internal gear that meshes with the external gear in Patent Document 1. The input shaft is a hollow shaft having a large-diameter hollow portion.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-124730

[0006] In the reducer, cables and pipes for conveying air (hereinafter referred to as "wiring") pass through the hollow part. In order to leave a sufficient gap between the wiring and the hollow part, it is preferred that the hollow part is larger. However, if the hollow part is enlarged under the condition that the outer diameter of the reducer is constant, the strength of the reducer may be reduced. Summary of the invention

[0007] The present invention has been made in view of such a problem, and an object of the present invention is to provide an eccentric oscillating gear device capable of enlarging a hollow portion.

[0008] In order to solve the above-mentioned problems, an embodiment of the present invention provides an eccentric swinging gear device, which comprises an internal gear, an external gear, an eccentric body that makes the external gear swing, a wheel frame arranged on the side portion of the axial direction of the external gear, and a plurality of inner pins connected to the wheel frame at a position offset from the center of the wheel frame and passing through the external gear. In the eccentric swinging gear device, the ratio of the pitch circle diameter of the inner pin to the tooth top diameter of the external gear (pitch circle diameter / tooth top diameter) is 0.77 to 0.85, the ratio of the diameter of the inner pin to the tooth top diameter of the external gear (inner pin diameter / tooth top diameter) is 0.06 to 0.10, and the proportion of the inner pin on the circumference of the pitch circle of the inner pin (i.e., the inner pin occupancy rate) is greater than 0.25.

[0009] In addition, any combination of the above-mentioned constituent elements or any form in which constituent elements or expressions of the present invention in methods, systems, etc. are replaced with each other may also be practiced as additional modes of the present invention.

[0010] According to the present invention, there is provided an eccentric oscillating gear device capable of enlarging a hollow portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a side cross-sectional view showing an eccentric oscillating gear device according to the embodiment.

[0012] Figure 2 yes Figure 1 AA line cross-sectional view of an eccentric oscillating gear device.

[0013] Figure 3 yes Figure 1 An enlarged view of the external gear of the eccentric oscillating type gear device.

[0014] Figure 4 It is used to illustrate Figure 1 A diagram showing the dimensions of various parts of an eccentric oscillating type gear device.

[0015] Figure 5 Yes means Figure 1 Figure 1. Stress characteristics of components of an eccentric oscillating type gear device.

[0016] Figure 6 Yes means Figure 1 Figure 2. Stress characteristics of components of an eccentric oscillating type gear device.

[0017] Figure 7 Yes means Figure 1 Figure 3. Stress characteristics of components of an eccentric oscillating type gear device.

[0018] In the figure: 12-input shaft, 12a-eccentric part, 14-external gear, 14b-tooth root, 14c-center hole, 14d-pitch circle, 14e-tooth top, 14h-inner pin hole, 16-internal gear, 18-1st wheel frame, 20-2nd wheel frame, 22-housing, 24-1st main bearing, 26-2nd main bearing, 32-inner pin, 32d-pitch circle, 100-eccentric swing type gear device. DETAILED DESCRIPTION

[0019] Hereinafter, the preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the embodiments and the modified examples, the same or equivalent components and parts are marked with the same symbols, and repeated descriptions are appropriately omitted. In addition, in each of the drawings, the size of the components is appropriately enlarged or reduced for easy understanding. In addition, in each of the drawings, a part of the components that are not important for the description of the embodiments is omitted.

[0020] Furthermore, terms including numbers such as 1 and 2 are used to describe various constituent elements, but such terms are only used to distinguish one constituent element from other constituent elements, and such terms are not used to limit the constituent elements.

[0022] Hereinafter, the structure of the eccentric oscillating gear device 100 according to the embodiment of the present invention will be described with reference to the drawings. Figure 1 It is a side cross-sectional view schematically showing the eccentric oscillating gear device 100 according to the present embodiment. Figure 2 yes Figure 1 The application of the eccentric oscillating gear device 100 is not limited, but in this example, the eccentric oscillating gear device 100 can be used in the joints of a multi-joint robot.

[0023] Next, the overall structure of the eccentric oscillating gear device 100 will be described. The eccentric oscillating gear device 100 mainly includes: an input shaft 12; an external gear 14; an internal gear 16; carriers 18 and 20; a housing 22; main bearings 24 and 26; an eccentric bearing 30; an inner pin 32; and input shaft bearings 33 and 34.

[0024] Hereinafter, the direction along the central axis La of the internal gear 16 is referred to as the "axial direction", and the circumferential direction and the radial direction of a circle centered on the central axis La are referred to as the "circumferential direction" and the "radial direction", respectively. Also, hereinafter, for the sake of convenience, one side in the axial direction (the right side in the figure) is referred to as the input side, and the other side (the left side in the figure) is referred to as the opposite input side. Such directional marking does not limit the use posture of the eccentric oscillating gear device 100, and the eccentric oscillating gear device 100 can be used in any posture.

[0025] The carriers 18 and 20 include a first carrier 18 disposed on the opposite side of the input of the external gear 14 and a second carrier 20 disposed on the input side of the external gear 14. The main bearings 24 and 26 include a first main bearing 24 disposed on the opposite side of the input of the external gear 14 and a second main bearing 26 disposed on the input side of the external gear 14. The input shaft bearings 33 and 34 include a first input shaft bearing 33 disposed on the opposite side of the input of the external gear 14 and a second input shaft bearing 34 disposed on the input side of the external gear 14.

[0026] The eccentric oscillating gear device 100 of this embodiment is a center crank type in which the input shaft (eccentric body shaft) 12 is provided coaxially with the center axis La of the internal gear 16. The eccentric oscillating gear device 100 has a hollow portion H extending axially through the central portion thereof. The hollow portion H is provided in the input shaft 12.

[0027] The housing 22 constitutes the outer shell of the eccentric oscillating gear device 100. The carriers 18 and 20 are arranged inside the housing 22 and rotate relative to the housing 22. The input shaft 12 has a hollow cylindrical shape having a hollow portion H at its center. For example, a power transmission component such as a gear or a pulley is connected to the end of the input side of the input shaft 12 by a fastener such as a bolt, and the rotation of the motor arranged at a position offset from the hollow portion H is transmitted thereto.

[0028] The input shaft 12 has a plurality of eccentric portions 12a, which function as eccentric bodies that cause the external gear 14 to swing. In this example, the input shaft 12 has two eccentric portions 12a that are 180° out of phase with each other. Both ends of the input shaft 12 are supported on the wheel carriers 18 and 20 via input shaft bearings 33 and 34. In addition, the number of eccentric portions 12a is not limited to two, and may be one or more than three.

[0029] The structures of the input shaft bearings 33 and 34 are not limited, but in this example, the rolling elements of the first input shaft bearing 33 are balls (spherical bodies), and the rolling elements of the second input shaft bearing 34 are rollers (cylindrical bodies).

[0030] The external gear 14 is rotatably supported by the corresponding eccentric portion 12a via an eccentric bearing 30. A center hole 14c and a plurality of inner pin holes 14h are formed in the external gear 14. The center hole 14c is a through hole provided at the center of the external gear 14. The plurality of inner pin holes 14h are through holes provided on the same circumference (on the pitch circle) at positions offset from the center of the external gear 14. Figure 2 In the example of FIG. 1 , ten inner pin holes 14h are arranged at intervals of 36° in the circumferential direction. The inner pin 32 is inserted into the inner pin hole 14h. The outer teeth formed on the outer periphery of the external gear 14 rotate while meshing with the inner teeth of the internal gear 16, so that the external gear 14 swings.

[0031] The internal gear 16 meshes with the external gear 14. The internal gear 16 of the present embodiment is composed of an internal gear body integrated with the housing 22 and an outer pin 16p (pin member) rotatably supported on the internal gear body. The outer pin 16p constitutes the internal teeth of the internal gear 16. The number of internal teeth of the internal gear 16 (the number of outer pins 16p) is slightly greater than the number of external teeth of the external gear 14 (in this example, only one more).

[0032] The first carrier 18 and the second carrier 20 are rotatably supported by the housing 22 via the main bearing 24 and the main bearing 26. The first carrier 18 supports the input shaft 12 via the first input shaft bearing 33. The second carrier 20 supports the input shaft 12 via the second input shaft bearing 34.

[0033] The first carrier 18 and the second carrier 20 are connected to each other via the inner pins 32. The inner pins 32 penetrate the inner pin holes 14h of the external gear 14 in the axial direction at positions offset in the radial direction from the axial center of the external gear 14.

[0034] One of the wheel carriers 18, 20 and the housing 22 functions as an output component that outputs rotational power to the reduced gear, and the other functions as a fixed component fixed to an external component for supporting the eccentric oscillating gear device 100. In the present embodiment, the output components are the first wheel carrier 18 and the second wheel carrier 20, and the fixed component is the housing 22.

[0035] In this example, ten inner pins 32 are arranged at intervals of 36° in the circumferential direction on the same circumference (on the pitch circle) offset from the center (axis center) of the first wheel carrier 18. Figure 1 Only one inner pin 32 is shown in FIG. The inner pin 32 is fixed to (connected to) the first wheel frame 18 on the opposite side of the input, and is fixed to (connected to) the second wheel frame 20 on the input side. The inner pin 32 connects the first wheel frame 18 and the second wheel frame 20. Figure 2 In the example of , the inner pin 32 is formed integrally with the first wheel frame 18, and its input side is fixed to the second wheel frame 20 by a bolt B2. A sleeve 32s is provided on the outer periphery of the inner pin 32. The inner pin 32 is inserted into the inner pin hole 14h with a gap between it and the inner pin hole 14h. The inner pin 32 abuts against a part of the inner pin hole 14h via the sleeve 32s. The inner pin 32 restricts the rotation of the outer gear 14 and only allows it to swing.

[0036] The main bearings 24 and 26 are arranged between the first wheel carrier 18 and the housing 22 and between the second wheel carrier 20 and the housing 22. The structure of the main bearings 24 and 26 is not limited, but in this example, the main bearings 24 and 26 are angular contact ball bearings whose rolling elements are spheres. The outer rings of the main bearings 24 and 26 are supported by the housing 22. The inner ring of the first main bearing 24 is formed integrally with the wheel carrier 18. The inner ring of the second main bearing 26 is formed integrally with the wheel carrier 20.

[0037] The housing 22 is a hollow cylindrical member surrounding the wheel frames 18 and 20. The housing 22 has a large diameter portion 22f extending radially outward. The large diameter portion 22f is provided with a bolt hole 22h penetrating in the axial direction. The large diameter portion 22f is connected to the external counterpart member 50.

[0038] An oil seal 28 is provided between the housing 22 and the first carrier 18 to seal the lubricant from the main bearing 24 .

[0039] Hereinafter, the characteristic structure of this embodiment will be described.

[0040] The inventors of the present invention have studied eccentric oscillating gear devices, and as a result, have obtained the following insights. Eccentric oscillating gear devices are used in various applications (for example, industrial robots or machine tools, etc.). Wiring such as cables passes through the hollow portion of the eccentric oscillating gear device. If the gap between the wiring and the hollow portion is small, they interfere with each other, causing stress to be applied to the wiring, which may cause damage to the wiring. Therefore, from the perspective of leaving a surplus gap between the wiring and the hollow portion, it is preferred that the diameter of the hollow portion is larger.

[0041] The load applied to the gear device is large in a large gear device and small in a small gear device. Therefore, the hollow portion diameter can be generalized by using the relationship between it and the size of the gear device. From the perspective of reducing the impact of the shape change of the housing, in this specification, the diameter of the hollow portion is generalized by using the ratio (hollow portion diameter / tooth tip diameter) to the diameter of the circle passing through each tooth tip of the external gear (hereinafter referred to as the "tooth tip diameter"). Hereinafter, this diameter ratio is sometimes referred to as the hollow portion diameter ratio.

[0042] Next, refer to Figure 3 and Figure 4 The stress of each part of the eccentric oscillating gear device 100 with respect to the load will be described. Figure 3 It is a partial enlarged view of the external gear 14 . Figure 4 This is an illustration for explaining the dimensions of each part. Figure 4 , the hollow diameter Dh, the tooth tip diameter De, and the pitch circle diameter Dp are shown. The tooth tip diameter De is the diameter of a circle passing through each tooth tip 14e. The pitch circle diameter Dp is the diameter of a pitch circle 32d passing through the center of each inner pin 32 (pitch circle diameter / PCD).

[0043] The inventors of the present invention have repeatedly conducted experiments and simulation tests on the eccentric oscillating gear device 100 of the present embodiment from the viewpoint of increasing the hollow portion diameter Dh, and studied the influence of changing the dimensions of each part. As a result, it was found that the stress of the inner pin 32, the portion 14j between the tooth root 14b of the external gear 14 and the inner pin hole 14h, and the portion 14k between the center hole 14c and the inner pin hole 14h are important. In other words, it was confirmed that if the stress of these portions meets the stress standard determined by the market demand in the general use of the eccentric oscillating gear device such as an industrial robot or a machine tool, it is possible to achieve a life strength suitable for practical use.

[0044] First, the influence of changing the dimensions of each part will be described. If the hollow diameter Dh is increased, the wall thickness of the portion 14k between the center hole 14c of the external gear 14 and the inner pin hole 14h will become thinner, so the larger the pitch circle diameter Dp of the inner pin 32 (which can also be called the pitch circle diameter of the inner pin hole 14h), the more advantageous it is. On the other hand, if the pitch circle diameter Dp is too large, the wall thickness of the portion 14j between the tooth root 14b of the external gear 14 and the inner pin hole 14h will become thinner, which may result in failure to meet the desired strength.

[0045] Furthermore, in order to increase the hollow diameter Dh while ensuring the wall thickness of the portion 14k and the wall thickness of the portion 14j, the smaller the inner pin hole diameter Dr, the better. On the other hand, if the inner pin hole diameter Dr is reduced, the inner pin diameter Dq will also become smaller, and in this case, the inner pin strength may not be satisfied.

[0046] Furthermore, in order to minimize the inner pin diameter Dq and meet the strength requirements, it is possible to consider increasing the number of inner pins to disperse the load borne by each inner pin. In order to increase the overall strength of multiple inner pins, the inner pin occupancy rate Eq can also be increased. However, if the inner pin occupancy rate Eq is increased excessively, the intervals between the inner pins will become smaller, which may cause manufacturing problems such as difficulty in forging or interference of tools with the inner pins during processing. In addition, the inner pin occupancy rate Eq is the proportion of the inner pin 32 on the circumference of the pitch circle 14d of the inner pin 32.

[0047] The inventors of the present invention realized that in order to satisfy the stress criterion and enlarge the hollow portion diameter Dh, it is important to find the appropriate ranges of the pitch diameter Dp, inner pin diameter Dq and inner pin occupancy rate Eq of the inner pin 32. In the present invention, it can be said that it is very important to think of this concept itself.

[0048] Next, refer to Figure 5 to Figure 7 The relationship between the pitch circle diameter Dp, the inner pin diameter Dq, and the inner pin occupancy rate Eq of the inner pin 32 and the stress of each part is explained. The pitch circle diameter Dp and the inner pin diameter Dq can be generalized by using the relationship between them and the size of the gear device. In the following, the pitch circle diameter Dp and the inner pin diameter Dq are regarded as the ratio of them to the tooth tip diameter De of the external gear 14.

[0049] exist Figure 5 to Figure 7In the figure, the vertical axis represents the stress of each part. In these figures, (a) represents the characteristic line of the stress of the inner pin 32, (b) represents the characteristic line of the stress of the portion 14j between the tooth root 14b of the external gear 14 and the inner pin hole 14h, and (c) represents the characteristic line of the stress of the portion 14k between the center hole 14c and the inner pin hole 14h. These stresses are the stresses generated in each part when a prescribed test load is applied to the gear device. The prescribed test load is a load set to simulate the load resistance of the market demand for the gear device. In addition, "benchmark" represents the benchmark level (upper limit level) of stress determined by market demand. In these figures, the value of the horizontal axis at the intersection of the characteristic line of stress and the benchmark line is the lower limit or upper limit of the benchmark range of stress (hereinafter referred to as "lower limit" or "upper limit"). That is, when the value of the horizontal axis is within the range from the lower limit to the upper limit, it can be said that the stress is within the benchmark range.

[0050] Figure 5 The figure shows the changes in stress of the inner pin 32, the portion 14j and the portion 14k when the ratio of the pitch circle diameter Dp to the tooth tip diameter De (pitch circle diameter Dp / tooth tip diameter De) is changed. The horizontal axis of the figure is the ratio of the pitch circle diameter Dp to the tooth tip diameter De.

[0051] like Figure 5 As shown in the figure, as the pitch circle diameter Dp increases, the stress of the inner pin 32 and part 14k decreases, and the stress of part 14j increases. As can be seen from the figure, when the ratio of the pitch circle diameter Dp to the tooth tip diameter De is in the range of 0.77 to 0.85, the stresses of the inner pin 32, part 14j and part 14k all fall within the reference range. The lower limit of part 14k is 0.77, which is greater than the lower limit of the inner pin 32, and the inclination of the characteristic line of stress is also greater, so it becomes the lower limit of the entire range. The upper limit of part 14j is 0.85, which becomes the upper limit of the entire range.

[0052] Figure 6 The figure shows the changes in stress of the inner pin 32, the portion 14j and the portion 14k when the ratio of the inner pin diameter Dq to the tooth tip diameter De (inner pin diameter Dq / tooth tip diameter De) is changed. Figure 6 As shown in the figure, as the inner pin diameter Dq increases, the stress of the inner pin 32 decreases, and the stress of the part 14j and the part 14k increases. As can be seen from the figure, when the ratio of the inner pin diameter Dq to the tooth top diameter De is in the range of 0.06 to 0.10, the stresses of the inner pin 32, the part 14j and the part 14k all fall within the reference range. The lower limit of the inner pin 32 is 0.06, which becomes the lower limit of the entire range. The upper limit of the part 14j is 0.10, which is smaller than the upper limit of the part 14k, and the inclination of the characteristic line of the stress is also greater, so it becomes the upper limit of the entire range.

[0053] Figure 7It shows the change of stress of the inner pin 32, part 14j and part 14k when the inner pin occupancy ratio Eq is changed. Figure 7 As shown, as the internal sales occupancy rate Eq increases, the stress of the internal sales 32, part 14j and part 14k all decreases. As can be seen from the figure, when the internal sales occupancy rate Eq is within the range of 0.25 or more, the stress of the internal sales 32, part 14j and part 14k all fall within the reference range. The lower limit of the internal sales 32 is 0.25, which is greater than the lower limit of parts 14j and 14k, and the inclination of the characteristic line of stress is also greater, so it becomes the lower limit of the entire range. In addition, the upper limit of the internal sales 32, part 14j and part 14k is limited by the processing limit. If the processing technology is improved and the processing limit is increased, the upper limit will become higher.

[0054] Therefore, when all of the following conditions (1) to (3) are satisfied, it can be said that the eccentric oscillating gear device 100 satisfies the stress standard determined by the market demand for general use.

[0055] (1) The ratio of the pitch circle diameter Dp of the inner pin 32 to the tooth tip diameter De of the external gear 14 (pitch circle diameter Dp / tooth tip diameter De) is 0.77 to 0.85.

[0056] (2) The ratio of the diameter Dq of the inner pin 32 to the tooth tip diameter De of the external gear 14 (diameter Dq of the inner pin 32 / tooth tip diameter De) is 0.06 to 0.10.

[0057] (3) The proportion of the inner sales 32 on the circumference of the pitch circle of the inner sales 32 (ie, the inner sales occupancy rate Eq) is greater than 0.25.

[0058] If the internal sales occupancy rate Eq is too large, the distance between adjacent internal pin holes 14h will become smaller, which may lead to insufficient rigidity during hole processing and reduced processing accuracy. Therefore, the internal sales occupancy rate Eq of this embodiment is set to less than 0.4. In this case, the reduction in processing accuracy can be suppressed.

[0059] The market requires that the gear device has a hollow portion of a size that can leave a sufficient gap between the wiring such as a cable and the hollow portion. In the eccentric oscillating gear device 100 of the present embodiment, the input shaft 12 having the eccentric portion 12a adopts a hollow structure having a hollow portion H. By adopting the above structure, a large-diameter hollow portion H is achieved in which the ratio of the diameter Dh of the hollow portion H to the tooth tip diameter De (hollow portion diameter Dh / tooth tip diameter De) is 0.4 or more. In this case, a sufficient gap can be left between the wiring and the hollow portion H, and the market demand can be met.

[0060] In an eccentric oscillating gear device, as the reduction ratio becomes smaller, the eccentricity of the eccentric portion 12a becomes larger, and the diameter Dr of the inner pin hole 14h also becomes larger. Therefore, as the reduction ratio becomes smaller, it is more difficult to increase the diameter of the hollow portion H. However, in the eccentric oscillating gear device 100 of the present embodiment adopting the above-mentioned structure, even if the reduction ratio is 30 or less, a large-diameter hollow portion H (a large-diameter hollow portion H in which the ratio of the diameter Dh of the hollow portion H to the tooth top diameter De (hollow portion diameter Dh / tooth top diameter De) becomes 0.4 or more) can be realized.

[0061] As described above, by optimizing the three indices of the pitch circle diameter Dp, the inner pin diameter Dq, and the inner pin occupancy rate Eq, it is possible to satisfy the inner pin stress standard and the external gear (14j portion, 14k portion) stress standard determined by the market demand for general use of the eccentric oscillating gear device 100. In addition, the present invention obtains the optimal ranges of the three indices of the pitch circle diameter Dp, the inner pin diameter Dq, and the inner pin occupancy rate Eq, and shows the results.

[0062] Next, the operation of the eccentric oscillating speed reducer 100 of the above structure will be described. If the rotation is transmitted from the motor to the input shaft 12, the eccentric portion 12a of the input shaft 12 rotates around the rotation center line passing through the input shaft 12, and causes the external gear 14 to oscillate via the eccentric bearing 30. If the external gear 14 oscillates, the meshing positions of the external gear 14 and the internal gear 16 deviate sequentially. As a result, each time the input shaft 12 rotates once, one of the external gear 14 and the internal gear 16 rotates by an amount corresponding to the difference in the number of teeth between the external gear 14 and the internal gear 16. In the present embodiment, the external gear 14 rotates, and the decelerated rotation is output from the first wheel frame 18 and the second wheel frame 20 via the inner pin 32.

[0063] Next, the characteristic structure of the eccentric oscillating gear device 100 having the above structure will be described. If the above three indicators are within the optimal range, an eccentric oscillating gear device that can increase the diameter Dh of the hollow portion H can be provided.

[0064] The above is the description of the implementation mode.

[0065] The examples of the embodiments of the present invention are described in detail above. The above embodiments are all specific examples for implementing the present invention. The contents of the embodiments are not intended to limit the technical scope of the present invention. Various design changes such as changes, additions, and deletions of constituent elements can be made without departing from the scope of the idea of ​​the invention specified in the technical solution. In the above embodiments, the contents that can make such design changes are explained by marking "implementation mode" and "implementation mode", but this does not mean that design changes are not allowed without such markings. In addition, the hatched lines marked on the cross-sections of the accompanying drawings are not used to limit the material of the objects marked with hatched lines.

[0066] In the following, a modification example is described. In the drawings and description of the modification example, the same reference numerals are given to the same or equivalent components and parts as those in the embodiment. The description repeated with the embodiment is appropriately omitted, and the structure different from the embodiment is described in detail.

[0067] [Modifications]

[0068] In the description of the embodiment, an example is shown in which the housing 22 is composed of an integral member, but the housing may be composed of a plurality of members.

[0069] In the description of the embodiment, an example in which the number of the external gears 14 is two is shown, but the number of the external gears may be one or three or more.

[0070] In the description of the embodiment, an example of a pin member for connecting the wheel carriers 18 and 20 having an inner pin 32 that participates in the transmission of the driving force of the external gear 14 is shown. As a pin member for connecting the wheel carriers 18 and 20, a wheel carrier pin that is different from the inner pin 32 and does not participate in the transmission of the driving force may be provided.

[0071] In the description of the embodiment, an example is shown in which the inner pin 32 is formed integrally with the first carrier 18 , but the inner pin 32 may be formed separately from the first carrier 18 and connected with a fixing member such as a bolt.

[0072] In the description of the embodiment, an example is shown in which the number of inner pins 32 and the number of inner pin holes 14h are ten, but these numbers may be less than nine or more than eleven. Furthermore, the number of inner pins 32 may be less than the number of inner pin holes 14h.

[0073] In the description of the embodiment, an example is shown in which the inner rings of the main bearings 24 and 26 are formed integrally with the carriers 18 and 20, but the inner rings of the main bearings may be formed separately from the carriers.

[0074] Furthermore, the present invention is particularly effective for an eccentric oscillating gear device having the hollow portion H, but is not limited thereto and can also be applied to an eccentric oscillating gear device having an input shaft 12 having no hollow portion H.

[0075] The above-mentioned modifications also achieve the same effects as those of the embodiment.

[0076] Any combination of the constituent elements and the modified examples of the above-described embodiment is also effective as an embodiment of the present invention. A new embodiment generated by the combination has the effects of the combined embodiment and the modified examples.

Claims

1. An eccentric oscillating gear device, comprising an internal gear, an external gear, an eccentric body for oscillating the external gear, a wheel carrier arranged on the side of the axial direction of the external gear, and a plurality of inner pins connected to the wheel carrier at a position offset from the center of the wheel carrier and penetrating the external gear, wherein the eccentric oscillating gear device is characterized in that: The ratio of the pitch diameter of the inner pin to the tooth top diameter of the outer gear, i.e., the pitch diameter / tooth top diameter, is 0.77 to 0.

85. The ratio of the inner pin diameter to the tooth top diameter of the outer gear, i.e., the inner pin diameter / tooth top diameter, is 0.06 to 0.

10. The proportion of the domestic sales on the circumference of the domestic sales pitch circle, i.e., the domestic sales occupancy rate, is greater than 0.

25.

2. The eccentric oscillating gear device according to claim 1, characterized in that: The domestic sales share is less than 0.

4.

3. The eccentric oscillating gear device according to claim 1 or 2, characterized in that: The eccentric body shaft having the eccentric body is provided with a hollow structure, and the ratio of the hollow portion diameter to the tooth tip diameter, that is, the hollow portion diameter / tooth tip diameter is greater than 0.

4.

4. The eccentric oscillating gear device according to any one of claims 1 to 3, characterized in that: The reduction ratio is 30 or less.

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