Gear system

Abstract

To provide a gear device which can alleviate bending stress applied on a knock pin.SOLUTION: A gear device 100 includes an external gear 14, an internal gear 16, a first carrier 18 arranged on one side in an axial direction of the external gear 14, a second carrier 20 arranged on the other side in the axial direction of the external gear 14 and connected with the first carrier 18, and a knock pin 36 for positioning the connection position of the first carrier 18 and the second carrier 20. The first carrier 18 has a first knock pin hole 18a in which the knock pin 36 is inserted. The second carrier 20 has a second knock pin hole 20a in which the knock pin 36 is inserted. The first knock pin hole 18a has a first chamfer part at an opening part peripheral edge 18e. The second knock pin hole 20a has a second chamfer part at an opening part peripheral edge 20e. When an axial direction dimension of the first chamfer part is defined as H1, and an axial direction dimension of the second chamfer part is defined as H2, the sum of H1 and H2 is equal to or less than 0.9 mm.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gear device.

Background Art

[0002] The applicant of the present application has disclosed an eccentric swing type gear device in Patent Document 1 (FIG. 9). This gear device includes an output flange for extracting the rotation component of an external gear, and an opposing flange disposed on the side of the counter-output flange with the external gear interposed therebetween. The opposing flange is connected to the output flange via carrier pins and carrier bolts. In addition, knock pins are press-fitted into both flanges in order to strictly maintain the relative positions of the opposing flange and the output flange.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors of the present invention have obtained the following recognition regarding a gear device having two connected flanges. There is a demand for miniaturization of gear devices while increasing the transmission load. When the transmission load increases, a large torsional torque is applied between two axially connected flanges, and bending stress is applied to the knock pins press-fitted into both flanges. This bending stress increases when starting and stopping the gear device. If a large bending stress is repeatedly applied, the knock pins may be fatigued and break. It is also conceivable to thicken the knock pins, but in this case, it is disadvantageous for miniaturization. From these, the inventors of the present invention have recognized that there is room for improvement in gear devices from the viewpoint of reducing the bending stress applied to the knock pins.

[0005] The object of the present invention has been made in view of these problems, and is to provide a gear device that can reduce the bending stress applied to the knock pin. [Means for solving the problem]

[0006] To solve the above problems, a gear device according to one aspect of the present invention comprises an external gear, an internal gear, a first carrier arranged on one axial side of the external gear, a second carrier arranged on the other axial side of the external gear and connected to the first carrier, and a knock pin for positioning the connection between the first carrier and the second carrier, wherein the first carrier has a first knock pin hole into which the knock pin is inserted. The second carrier has a second knock pin hole into which the knock pin is inserted. The first knock pin hole has a first chamfer on the periphery of its opening. The second knock pin hole has a second chamfer on the periphery of its opening. When the axial dimension of the first chamfer is H1 and the axial dimension of the second chamfer is H2, the sum of H1 and H2 is 0.9 mm or less.

[0007] Furthermore, any combination of the above components, or in which the components or expressions of the present invention are mutually substituted among methods, systems, etc., are also valid embodiments of the present invention. [Effects of the Invention]

[0008] According to the present invention, a gear device is available that can reduce the bending stress applied to the knock pin. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side cross-sectional view showing a gear device according to an embodiment. [Figure 2] This is an enlarged view showing the area around the knock pin hole of the gear mechanism in Figure 1. [Figure 3] This is a schematic diagram showing the relationship between the chamfer dimensions of the knock pin hole and the bending stress. [Figure 4] This is another schematic diagram showing the relationship between the chamfer dimensions of the knock pin holes and the bending stress. [Figure 5]This graph shows the relationship between the chamfer dimensions of the knock pin holes and durability. [Modes for carrying out the invention]

[0010] The present invention will be described below with reference to the drawings, based on preferred embodiments. In embodiments and modifications, the same or equivalent components and members will be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. In addition, the dimensions of the members in each drawing will be enlarged or reduced as appropriate to facilitate understanding. Furthermore, some members that are not important for explaining the embodiments will be omitted from the drawings. Furthermore, while terms including ordinal numbers such as "first" and "second" are used to describe various components, these terms are used solely to distinguish one component from others, and do not limit the components themselves.

[0011] [Embodiment] The configuration of the gear device 100 according to an embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a side cross-sectional view showing the gear device 100. The gear device 100 of this embodiment is a so-called distribution type eccentric oscillating reduction gear. This gear device 100 is configured to generate rotation of one of the internal gears and the external gears by oscillating the external gear that meshes with the internal gear, and to output the resulting rotation component from the output member to the driven device.

[0012] The gear unit 100 mainly comprises an input gear 70, a crankshaft 12, an external gear 14, an internal gear 16, carriers 18 and 20, a casing 22, and main bearings 24 and 26. Hereinafter, the direction along the central axis La of the internal gear 16 will be referred to as the "axial direction," and the circumferential and radial directions of the circle centered on that central axis La will be referred to as the "circumferential direction" and "radial direction," respectively. Also, for convenience, hereafter, one side of the axial direction (right side in the figure) will be referred to as the input side, and the other side (left side in the figure) will be referred to as the non-input side.

[0013] (Input gear) Three input gears 70 are arranged around the central axis La of the internal gear 16. The three input gears 70 are positioned at equal intervals of 120°, offset from the central axis La. Figure 1 shows only one input gear 70. Three crankshafts 12 are provided, corresponding to the three input gears 70. The crankshafts 12 are inserted through the center of the input gears 70 and support the input gears 70. A pair of crankshaft bearings 34 are provided on both axial sides of the crankshaft 12. The crankshafts 12 are provided so as to be rotatable integrally with the input gears 70. The three input gears 70 mesh with the external teeth (not shown) of a rotating shaft (not shown) provided on the central axis La. Rotational power is transmitted to this rotating shaft from a drive device (not shown), and the rotation of this rotating shaft causes the input gears 70 to rotate integrally with the crankshafts 12. The drive device is, for example, a motor, gear motor, engine, etc.

[0014] (crank axle) The crankshaft 12 in this embodiment is an eccentric shaft having a plurality of eccentric portions 12a for oscillating the external gear 14. The axes of the eccentric portions 12a are eccentric with respect to the rotational centerline of the crankshaft 12. In this embodiment, two eccentric portions 12a are provided, and the eccentric phases of adjacent eccentric portions 12a are shifted by 180°.

[0015] The crankshaft 12 is supported on its input side by the second carrier 20 via a crankshaft bearing 34, and on its non-input side by the first carrier 18 via a crankshaft bearing 34. The crankshaft bearing 34 on the non-input side is fitted and supported in the crankshaft hole 18h of the first carrier 18, and the crankshaft bearing 34 on the input side is fitted and supported in the crankshaft hole 20h of the second carrier 20. In other words, the crankshaft 12 is rotatably supported relative to the first carrier 18 and the second carrier 20. There are no particular restrictions on the configuration of the crankshaft bearing 34, but in this example it is a roller bearing having cylindrical rolling elements.

[0016] (Internal gear) The internal gear 16 meshes with the external gear 14. The internal gear 16 of the present embodiment has an internal gear main body 16a integrated with the casing 22, and external pins 17 arranged in a plurality of pin grooves formed at intervals in the circumferential direction on the internal gear main body 16a. The external pin 17 is a cylindrical pin member rotatably supported by the internal gear main body 16a. The external pin 17 may be a hollow member, but in this embodiment, it is a solid member. The external pin 17 constitutes the internal teeth of the internal gear 16. The number of external pins 17 (number of internal teeth) of the internal gear 16 is slightly more (in this example, just 1) than the number of external teeth of the external gear 14.

[0017] (External gear) The external gear 14 is provided individually corresponding to each of the plurality of eccentric portions 12a. The external gear 14 is rotatably supported by the corresponding eccentric portion 12a via an eccentric roller 32. In the external gear 14, three shaft holes 14p and three swing holes 14j are formed at a predetermined interval at positions offset from its axis.

[0018] <* The shaft holes 14p are provided at intervals of 12° at the same radial position with respect to each other. The shaft holes 14p penetrate in the axial direction, and the shaft portion 18s is inserted therethrough. The shaft holes 14p are formed larger than the outer diameter of the shaft portion 18s and have a size that does not contact the shaft portion 18s.

[0019] The swing holes 14j are provided at intervals of 120° at the same radial position with respect to each other. The swing holes 14j penetrate in the axial direction, and the eccentric portion 12a of the crankshaft 12 is inserted therethrough. The swing holes 14j are formed larger than the outer diameter of the eccentric portion 12a, and a plurality of eccentric rollers 32 are interposed between the swing holes 14j and the eccentric portion 12a. The plurality of eccentric rollers 32 are arranged at substantially equal intervals around the eccentric portion 12a and smoothly transmit the eccentric movement of the eccentric portion 12a to the swing holes 14j.

[0020] The external gear 14 is provided with a central hole 14h that penetrates axially. Corrugated teeth are formed on the outer circumference of the external gear 14, and as these teeth move in contact with the internal gear 16, the external gear 14 can oscillate in a plane normalized to the central axis.

[0021] (Carrier) The carriers 18 and 20 are positioned on the axial side of the external gear 14. The carriers 18 and 20 include a first carrier 18 positioned on the side of the external gear 14 that is not the input side, and a second carrier 20 positioned on the input side of the external gear 14. Hereinafter, the first carrier 18 and the second carrier 20 will be collectively referred to as "carrier". The carrier is rotatably supported by the casing 22 via a first main bearing 24 and a second main bearing 26. The carrier as a whole is a hollow disc or cylindrical shape. The carrier rotatably supports the crankshaft 12 via a crankshaft bearing 34.

[0022] The first carrier 18 has a central hole 18k formed in the radial center of the first carrier 18. The second carrier 20 has a central hole 20k formed in the radial center of the second carrier 20. The first carrier 18 and the second carrier 20 are connected via a shaft portion 18s.

[0023] (Shaft section) The shaft portion 18s will now be described. The shaft portion 18s is a columnar part that extends axially from the first carrier 18 toward the second carrier 20, and is formed integrally with the first carrier 18. Multiple shaft portions 18s (three in this embodiment) are provided at positions radially offset from the axis of the external gear 14 (first carrier 18). The shaft portions 18s are inserted through the shaft hole 14p formed in the external gear 14 with a gap between them.

[0024] The end of the shaft portion 18s is in contact with the end face of the second carrier 20 on the non-input side and is fixed to the second carrier 20. The gear device 100 has a knock pin 36 for connecting and positioning the first carrier 18 and the second carrier 20, and a connecting bolt 40 for connecting the first carrier 18 and the second carrier 20. When the shaft portion 18s is fixed to the second carrier 20, it is positioned by the knock pin 36 and fixed by the connecting bolt 40.

[0025] The knock pin 36 and the connecting bolt 40 are spaced apart in the circumferential direction. The knock pin 36 is positioned radially inward from the connecting bolt 40. In this case, by positioning the connecting bolt 40 radially outward, the pitch circle diameter of the connecting bolt 40 can be increased, thereby improving the connection strength between the first carrier 18 and the second carrier 20. This improved connection strength reduces the bending stress on the knock pin 36. The bending stress on the knock pin 36 will be described later.

[0026] The shaft portion 18s functions as a connecting portion that contributes to the connection between the first carrier 18 and the second carrier 20. The shaft portion 18s of the first carrier 18 has a first knock pin hole 18a into which a knock pin 36 is inserted, and the second carrier 20 has a second knock pin hole 20a into which a knock pin 36 is inserted. Hereinafter, the first knock pin hole 18a and the second knock pin hole 20a will be collectively referred to as "knock pin hole".

[0027] For example, the knock pin 36 is a cylindrical pin with chamfered ends, and may be press-fitted into the first knock pin hole 18a of the first carrier 18 up to about half its length. The remaining half of the press-fitted knock pin 36 is positioned and press-fitted into the second knock pin hole 20a of the second carrier 20. The knock pin holes will be described in detail later.

[0028] (Casing) The casing 22 is a hollow cylindrical shape overall, and an internal gear 16 is provided on its inner circumference. A flange 22f is provided on the outer circumference of the casing 22. Through holes 22h and tapped holes 22j are provided in the flange 22f. These holes are used to connect the casing 22 to external members and driven devices.

[0029] The casing 22 is provided with a recess 22m for accommodating the outer ring of the first main bearing 24 and a recess 22n for accommodating the outer ring of the second main bearing 26. The casing 22 and the carrier are configured to rotate relative to each other via the first main bearing 24 and the second main bearing 26.

[0030] (Main bearing) The main bearings 24 and 26 include a first main bearing 24 positioned between the first carrier 18 and the casing 22, and a second main bearing 26 positioned between the second carrier 20 and the casing 22. The main bearings 24 and 26 of this embodiment include a plurality of rolling elements 28 and a retainer (not shown). The plurality of rolling elements 28 are spaced apart in the circumferential direction. The rolling elements 28 of this embodiment are spherical. The retainer maintains the relative positions of the plurality of rolling elements 28 and rotatably supports the plurality of rolling elements 28. The main bearings 24 and 26 may be roller bearings or cross roller bearings.

[0031] The main bearings 24 and 26 of this embodiment are equipped with an outer ring 30 having a rolling surface for the rolling elements 28, but no inner ring. The inner rolling surfaces of the main bearings 24 and 26 are provided on the outer circumferential surfaces of the carriers 18 and 20 instead of an inner ring. The outer ring 30 is fixed to the casing 22 by a fitting such as a clearance fit, interference fit, or intermediate fit. An oil seal 22s is provided between the first carrier 18 and the casing 22. The oil seal 22s is positioned on the non-input side of the first main bearing 24.

[0032] One of the first carrier 18 and the casing 22 functions as an output member that outputs rotational power to the driven device, while the other functions as a fixed member that is fixed to an external member for supporting the gear device 100. For example, if the first carrier 18 is the output member and the casing 22 is the fixed member, the input shaft of the driven device may be connected to the central hole 18k of the first carrier 18.

[0033] Next, the connecting structure of the first carrier 18 and the second carrier 20 will be described with reference to Figures 2 to 5. Figure 2 is an enlarged view showing the area around the knock pin hole. This figure shows an enlarged view of the part indicated by circle E in Figure 1, and the knock pin 36 is omitted from the description. The first knock pin hole 18a has a first chamfered portion 18f on the periphery 18e of the opening, and the second knock pin hole 20a has a second chamfered portion 20f on the periphery 20e of the opening. Hereinafter, the first chamfered portion 18f and the second chamfered portion 20f will be collectively referred to as the "chamfered portion". The axial dimension of the first chamfered portion 18f will be H1, and the axial dimension of the second chamfered portion 20f will be H2. Hereinafter, the axial dimensions H1 and H2 will be collectively referred to as the "chamfered dimension".

[0034] The inventors have studied a gear device 100 having a first carrier 18 and a second carrier 20 connected in the axial direction and have obtained the following findings.

[0035] Figures 3 and 4 are schematic diagrams showing the relationship between the chamfer dimension of the knock pin hole and the bending stress Sb applied to the knock pin 36. Figure 3 shows the case where the chamfer dimension is small, and Figure 4 shows the case where the chamfer dimension is large. When the first carrier 18 accelerates or decelerates, the second carrier 20 follows with a slight delay and accelerates or decelerates accordingly. When the second carrier 20 accelerates or decelerates in accordance with the first carrier 18 in this way, twisting occurs between them, and bending stress Sb is applied to the knock pin 36. In other words, bending stress Sb is applied to the knock pin 36 when the gear unit 100 is started and stopped. If a large bending stress Sb is repeatedly applied, it is conceivable that the knock pin 36 will fatigue and break.

[0036] The investigation revealed that the bending stress Sb differs depending on the chamfer size of the knock pin hole. In other words, as shown in Figures 3 and 4, the bending stress Sb on the knock pin 36 is small when the chamfer size is small and large when the chamfer size is large, and this difference can be said to affect the durability of the knock pin 36.

[0037] Based on this finding, the inventors investigated the relationship between the chamfer dimensions of the knock pin hole and the durability of the knock pin 36. Figure 5 is a graph showing the relationship between the chamfer dimensions of the knock pin hole and durability. This graph shows the number of cycles (hereinafter referred to as "allowable cycles") until the knock pin 36 breaks in an ON-OFF test in which the gear unit 100 is repeatedly started and stopped while a test load torque (e.g., allowable load torque) is applied. The horizontal axis of this graph represents the sum of the axial dimensions H1 and H2 of the knock pin hole, Hw, and the vertical axis represents the number of cycles until breakage occurs.

[0038] From this graph, it can be seen that when the sum of axial dimensions H1 and H2, Hw, is 0.9 mm, the allowable number of cycles is 12,000, and when the sum of Hw is 1.0 mm, the allowable number of cycles is 5,250, less than half. Also, when the sum of Hw is 0.8 mm, the allowable number of cycles is 14,532, and when the sum of Hw is 0.7 mm, the allowable number of cycles is 15,250, which is not significantly different from when the sum of Hw is 0.9 mm. In other words, when the sum of Hw is 0.9 mm or less, the allowable number of cycles tends to saturate at around 15,000. Furthermore, from the viewpoint of facilitating the processing of the chamfered portion, the sum of Hw may be 0.1 mm or more, preferably 0.3 mm or more.

[0039] Furthermore, as shown in Figure 5, the allowable number of cycles when the sum Hw is 1.1 mm is 4500, which is not significantly different from when the sum Hw is 1.0 mm. In other words, when the sum Hw is 1.0 mm or more, the allowable number of cycles tends to saturate at around 5000 cycles. From these findings, it can be said that the durability of the knock pin 36 is higher when the sum Hw is 0.9 mm or less compared to when the sum Hw is 1.0 mm or more.

[0040] The inventors further conducted the same ON-OFF tests as described above, using combinations in which one of the axial dimensions H1 and H2 was increased and the other was decreased. As a result, regardless of the combination of the magnitudes of the axial dimensions H1 and H2, it was confirmed that, as described above, the durability of the knock pin 36 was higher when the sum Hw was 0.9 mm or less compared to when the sum Hw was 1.0 mm or more. In other words, it can be said that the axial dimensions H1 and H2 can be set arbitrarily as long as the sum Hw is 0.9 mm or less. This is thought to be because bending stress is applied to the knock pin 36 with one corner of the chamfer as the fulcrum and the other corner as the point of application, so if the distance between these corners (= sum Hw) is the same, the magnitude of the bending stress hardly changes.

[0041] For example, the chamfered portion of a dowel pin hole can be formed by machining, such as drilling or milling. As the axial dimensions H1 and H2 of the chamfered portion increase, the machining time for this process increases accordingly. Therefore, the axial dimension H1 may be 0.45 mm or less, and the axial dimension H2 may also be 0.45 mm or less. In this case, the machining time can be shortened compared to a configuration with larger axial dimensions.

[0042] The inventors further conducted the same ON-OFF tests as described above on gear sets A, B, and C, which are of different sizes. Gear sets A, B, and C have the same configuration as in this embodiment, but in terms of allowable load torque, gear set B is 5 times that of gear set A, and gear set C is 20 times that of gear set A. In addition, in terms of knock pin diameter, gear set B is 1.4 times that of gear set A, and gear set C is 2 times that of gear set A.

[0043] The results of this test confirmed that, for gear sets A, B, and C, the durability of the knock pins was higher when the sum Hw was 0.9 mm or less compared to when the sum Hw was 1.0 mm or more, as described above. The reason why the same results are obtained regardless of the size of the gear set is thought to be that as the size of the gear set increases, both the allowable load torque and the diameter of the knock pin increase, and the effects of these increases cancel each other out. Therefore, the same size chamfer can be applied to gear sets of different sizes.

[0044] Referring to Figure 2, the inclination angle of the chamfered portion will be explained. If the angles θ1 and θ2 that the first and second chamfered portions 18f and 20f make with respect to the axial direction are too small, galling is likely to occur when the knock pin 36 is pressed in. Also, if the angles θ1 and θ2 are too large, the function of the chamfered portion as a guide is impaired, making press-fitting difficult. For these reasons, in this embodiment, the angles θ1 and θ2 are set within the range of 30° to 60°. Within this range, galling during press-fitting can be suppressed, and practical productivity can be achieved.

[0045] The operation of the gear device 100 configured as described above will now be explained. When rotational power is transmitted from the drive device to the rotating shaft, the rotational power is distributed from the rotating shaft to a plurality of input gears 70, and each input gear 70 rotates in the same phase. As each input gear 70 rotates, the eccentric portion 12a of the crankshaft 12 rotates around the rotational center line passing through the crankshaft 12, and the external gear 14 oscillates via the eccentric rollers 32 due to the eccentric portion 12a. As the external gear 14 oscillates, the meshing positions of the external gear 14 and the external pins 17 of the internal gear 16 shift sequentially. As a result, with each rotation of the crankshaft 12, one of the external gear 14 and the internal gear 16 rotates by an amount equivalent to the difference between the number of teeth of the external gear 14 and the number of external pins 17 of the internal gear 16. In this embodiment, the external gear 14 rotates, and reduced rotation is output from the first carrier 18.

[0046] The embodiments of the present invention have been described in detail above. The embodiments described above are merely examples of how to implement the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes, such as changes, additions, and deletions of components, are possible as long as they do not depart from the spirit of the invention as defined in the claims. In the embodiments described above, such design changes are described with notations such as "of the embodiments" or "in the embodiments," but this does not mean that design changes are not permitted for contents without such notations. Furthermore, the hatching applied to the cross-sections in the drawings does not limit the material to which the hatching is applied.

[0047] The following describes modified examples. In the drawings and descriptions of the modified examples, components and parts that are the same as or equivalent to those in the embodiments are denoted by the same reference numerals. Descriptions that overlap with those in the embodiments will be omitted as appropriate, and the descriptions will focus on the configurations that differ from those in the embodiments.

[0048] [Differentiation] In the description of the embodiment, an example was shown in which the gear device 100 is a distribution-type eccentric oscillating reduction gear, but the present invention is not limited thereto. For example, the gear device 100 may be a center-crank type eccentric oscillating reduction gear in which the rotational centerline of the crankshaft 12 is located coaxially with the central axis La of the internal gear 16, or it may be a gear device having a different configuration, such as a simple planetary gear device.

[0049] In the description of the embodiment, the number of crankshafts 12 and input gears 70 was set to three, but the present invention is not limited to this. The number of crankshafts 12 and input gears 70 may be one, two, or four or more.

[0050] The description of the embodiment shows an example in which two external gears 14 are provided, but the present invention is not limited to this. Three or more external gears 14 may be provided. For example, the crankshaft may be provided with three eccentric portions 12a, each with a phase difference of 120°, and three external gears 14 may be provided that are oscillated by these three eccentric portions 12a. Alternatively, there may be only one external gear 14.

[0051] In the description of the embodiments, an example was shown in which the second main bearing 26 and the first main bearing 24 do not have inner rings, but the present invention is not limited thereto. The second main bearing 26 and the first main bearing 24, or one or both, may be bearings having inner rings.

[0052] Each of the above-described modifications produces the same functions and effects as the above-described embodiments.

[0053] Any combination of the embodiments and modifications described above is also useful as an embodiment of the present invention. The new embodiments resulting from these combinations possess the combined effects of each of the embodiments and modifications that are combined. [Explanation of Symbols]

[0054] 14...External gear, 16...Internal gear, 18...First carrier, 18a...First knock pin hole, 18e...Periphery of opening, 18f...First chamfer, 20...Second carrier, 20a...Second knock pin hole, 20e...Periphery of opening, 20f...Second chamfer, 36...Knock pin, 40...Bolt, 40...Connecting bolt, 100...Gear unit, H1, H2...Axial dimensions.

Claims

1. A gear device comprising: an external gear; an internal gear; a first carrier positioned on one axial side of the external gear; a second carrier positioned on the other axial side of the external gear and connected to the first carrier; a knock pin for positioning the first and second carriers; and a connecting bolt for connecting the first and second carriers, The first carrier has a first knock pin hole into which the knock pin is inserted, The second carrier has a second knock pin hole into which the knock pin is inserted, The first knock pin hole has a first chamfered portion around the periphery of the opening, The second knock pin hole has a second chamfered portion on the periphery of the opening on the first carrier side. When the axial dimension of the first chamfered portion is H1 and the axial dimension of the second chamfered portion is H2, the sum of H1 and H2 is 0.1 mm or more and 0.9 mm or less. The first carrier includes a columnar shaft portion that extends axially at a position radially offset from the axis of the external gear and is connected to the second carrier by the connecting bolt. The gear apparatus is characterized in that the knock pin is positioned radially inward from the connecting bolt.

2. The gear device according to claim 1, characterized in that the axial dimension H1 is 0.45 mm or less, and the axial dimension H2 is 0.45 mm or less.

3. The gear device according to claim 1 or 2, characterized in that the angle made with the axial direction of the first and second chamfered portions is within the range of 30° to 60°.

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