Eccentric oscillation speed reduction device and wave reduction device

Abstract

To provide an eccentric oscillation speed reduction device capable of improving a coupling structure with a motor shaft.SOLUTION: An eccentric oscillation type speed reduction device 100 comprises an input shaft 20, which is an eccentric body shaft, and a coupling shaft 5 connected to the input shaft 20, where the coupling shaft 5 has a connection hole 52 to which the motor shaft 12 is connected, and an outer diameter of a surrounding part 51 surrounding the connecting hole 52 of the coupling shaft 5 is larger than an outer diameter of a shaft end part 18 on the motor side of the input shaft 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an eccentric swing type reduction gear and a wave reduction gear.

Background Art

[0002] A reduction gear having a connection structure with a motor shaft is known. The applicant has disclosed in Patent Document 1 a technique related to a reduction gear having a connection structure with a motor shaft. This reduction gear has an input shaft having a hollow portion, a motor shaft inserted into this hollow portion, and a clamp fastener disposed outside the hollow portion of the input shaft. The clamp fastener fastens the input shaft and the motor shaft by frictional force.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor has obtained the following new recognition regarding the eccentric swing type reduction gear. For a reduction gear that reduces the rotation input from the motor shaft via the connection structure, further miniaturization is required. However, as the reduction gear is miniaturized, the diameter of the hollow portion that can be formed in the input shaft also becomes smaller. On the other hand, since the diameter of the motor shaft connected to the input shaft is determined according to the performance of the motor, the motor shaft may become large. In this case, the range of motor shafts that can be combined with the reduction gear becomes narrow. Patent Document 1 does not provide sufficient disclosure from the viewpoint of expanding the range of combinable motor shafts.

[0005] The present invention has been made in view of such problems, and one of the objects is to provide an eccentric swing type reduction gear capable of improving the connection structure with a motor shaft.

Means for Solving the Problems

[0006] To solve the above problems, an eccentric swing type reduction gear according to an aspect of the present invention is an eccentric swing type reduction gear including an input shaft that is an eccentric body shaft and a relay shaft connected to the input shaft, wherein the relay shaft has a connection hole to which a motor shaft is connected. The outer diameter of the surrounding portion surrounding the connection hole of the relay shaft is larger than the outer diameter of the shaft end portion on the motor side of the input shaft.

[0007] Another aspect of the present invention is a wave reduction gear. This device is a wave reduction gear including an input shaft that is an oscillation body shaft and a relay shaft connected to the input shaft, wherein the relay shaft has a connection hole to which a motor shaft is connected. The outer diameter of the surrounding portion surrounding the connection hole of the relay shaft is larger than the outer diameter of the shaft end portion on the motor side of the input shaft.

[0008] In addition, any combination of the above components, or those obtained by mutually replacing the components and expressions of the present invention between methods, systems, etc. are also effective as aspects of the present invention.

Effect of the Invention

[0009] According to the present invention, it is possible to provide an eccentric swing type reduction gear capable of improving the connection structure with a motor shaft.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described with reference to the respective drawings based on preferred embodiments. In the embodiments and modification examples, the same or equivalent components and members are denoted by the same reference numerals, and redundant descriptions are omitted as appropriate. Also, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Further, some of the members that are not important for explaining the embodiments are omitted in each drawing.

[0012] Also, terms including ordinals such as first and second are used to describe various components, but this term is used only for the purpose of distinguishing one component from another, and the components are not limited by this term.

[0013] [First Embodiment] Referring to FIGS. 1 - 5, an eccentric swing type deceleration device 100 (hereinafter referred to as "deceleration device 100") according to the first embodiment will be described. FIG. 1 is a cross-sectional view in side view showing an example of the deceleration device 100. This figure shows the deceleration device 100 in a state incorporated in the device unit 1. FIGS. 2 - 5 are views showing the respective members of the device unit 1. The device unit 1 includes a motor 11 which is an electric motor that rotationally drives a motor shaft 12, a deceleration unit 10 that decelerates and outputs the rotation of the motor shaft 12, and a connection mechanism 50 that connects the motor 11 to the deceleration unit 10.

[0014] Hereinafter, the direction along the central axis line La of the input shaft 20 is referred to as the "axial direction", the side where the motor shaft 12 of the input shaft 20 is connected in the axial direction (the right side in the figure) is referred to as the motor side, and the other side (the left side in the figure) is referred to as the anti-motor side. That is, the input shaft 20 extends from the motor side to the anti-motor side in the axial direction. Also, the circumferential direction and the radial direction of a circle centered on the central axis line La are referred to as the "circumferential direction" and the "radial direction", respectively.

[0015] The reduction unit 10 mainly includes an external gear 13, an internal gear 41, an input shaft 20, carriers 35 and 36, an inner pin 48, an eccentric bearing 16, a main bearing 37, first and second bearings 39 and 40 for supporting the input shaft 20, and a casing 80.

[0016] The reduction unit 10 can reduce the rotation input from the motor 11 and output it from the carrier 35 or the casing 80. In this example, it is output from the carrier 35. There is no limitation on the reduction unit 10 as long as it can reduce the input rotation and output it. The reduction unit 10 of the present embodiment is of a center crank type in which the central axis La of the input shaft 20 is provided on the same axis as the central axis of the internal gear.

[0017] The coupling mechanism 50 mainly includes a coupling shaft 5, an adapter ring 6, a clamp ring 7, and a cylindrical portion 8. The reduction device 100 has a configuration in which the coupling shaft 5 is fixed to the input shaft 20 of the reduction unit 10.

[0018] With the miniaturization of the reduction gear, the outer diameter of the input shaft also becomes smaller. When forming a coupling hole for coupling the motor shaft on the end face of the input shaft with a small outer diameter, the inner diameter of the coupling hole also becomes smaller. Since the outer diameter of the connectable motor shaft is limited by the inner diameter of the coupling hole, the size of the connectable motor becomes smaller. When a small motor outputs a large driving force, the internal temperature rise becomes large, which may impair reliability. For this reason, there is a demand for a reduction device that can connect motors of various sizes.

[0019] Therefore, the reduction device 100 of the present embodiment includes an input shaft 20 that is an eccentric shaft of the reduction unit 10 and a coupling shaft 5 connected to the input shaft 20. As shown in FIG. 2, the coupling shaft 5 has a coupling hole 52 to which the motor shaft 12 is connected, and is characterized in that the outer diameter D51 of the surrounding portion 51 surrounding the coupling hole 52 of the coupling shaft 5 is larger than the outer diameter D18 of the shaft end portion 18 on the motor side of the input shaft 20.

[0020] According to this configuration, since the outer diameter D51 of the surrounding portion 51 is larger than the outer diameter D18 of the shaft end portion 18, the connecting hole 52 can be made larger than when the connecting hole 52 is provided in the input shaft 20. Therefore, the range of the outer diameter of the motor shaft 12 that can be connected can be widened.

[0021] The motor 11 is a drive source of the speed reduction device 100 and is a servo motor in this embodiment. The motor 11 is not limited as long as it can output rotation to the speed reduction device 100, and motors based on various principles can be used. The motor 11 has a motor shaft 12 extending toward the speed reduction device 100. The motor shaft 12 is inserted into a connecting hole 52 of a coupling shaft 5 fixed to the input shaft 20 of the speed reduction device 100 and is clamped and connected by a clamp ring 7.

[0022] The cylindrical portion 8 will be described with reference to FIG. 1. The cylindrical portion 8 is a cylindrical member forming the outer shell of the connecting mechanism 50 and is disposed between the speed reduction portion 10 and the motor 11. The cylindrical portion 8 has a main body portion 81 having a cylindrical hollow portion 88, a speed reduction machine side fitting portion 82 that is inlay-fitted on the motor side of the speed reduction portion 10, a motor side fitting portion 83 that is inlay-fitted on the anti-motor side of the motor 11, and a seal support portion 87 where a seal member S2 for sealing the outer periphery of the coupling shaft 5 is disposed. The main body portion 81 has a shape that surrounds the clamp ring 7 with a gap therebetween. The main body portion 81 is provided with a tool hole 85 for inserting a tool such as a driver into a bolt B3 for tightening the clamp ring 7 and a tapped hole 86. A sealing bolt B4 for sealing the tapped hole 86 is screwed into the tapped hole 86. The tool hole 85 and the tapped hole 86 are in a twisted position with respect to the central axis La and communicate along a straight line extending in the vertical direction.

[0023] The seal support portion 87 is a small-diameter portion extending inward from the inner peripheral surface of the hollow portion 88, and a seal member S2 is disposed on the inner periphery of the seal support portion 87. The seal member S2 is disposed between the inner periphery of the seal support portion 87 and the outer periphery of the coupling shaft 5 and is an oil seal that reduces the leakage of the lubricant of the second bearing 40 described later.

[0024] Referring to FIGS. 1 and 2, the splined shaft 5 will be described. FIG. 2 is a cross-sectional view of the splined shaft 5 in side view. The splined shaft 5 has a cylindrical shape extending along the central axis line La and is fixed to the input shaft 20. In the embodiment, the splined shaft 5 has an annular portion 51, a connecting hole 52, a seal arrangement portion 53, a tightening portion 54, a slit 55, a non-motor side end portion 56, a bolt hole 57, and a convex portion 58.

[0025] The connecting hole 52 is a blind hole extending from the end face on the motor side toward the non-motor side along the central axis line La. The hole diameter D52 of the connecting hole 52 is larger than the hole diameter D28 of the hollow portion 28 (to be described later) of the input shaft 20. Since the connecting hole 52 is large, the outer diameter range of the motor shaft 12 that can be connected can be widened.

[0026] The connecting hole 52 is closed at the non-motor side end portion 56. The annular portion 51 is a cylindrical portion surrounding the connecting hole 52, and a seal arrangement portion 53 where a seal member S2 is arranged is provided in a part of the annular portion 51. As shown in FIG. 2, the outer diameter D53 of the seal arrangement portion 53 is larger than the outer diameter D18 of the shaft end portion 18 of the input shaft 20. In this case, the degree of freedom of the seal diameter is increased. That is, when miniaturizing the speed reduction device, it is often necessary to newly design a small seal member accordingly. However, in this configuration, since the degree of freedom of the seal diameter is increased, it is easy to use a standard seal member.

[0027] In the case of clamp connection, although it is almost impossible for the connecting portion to seize, it is conceivable that the connecting portion becomes long in the axial direction and the device becomes large-sized. Therefore, in this embodiment, the increase in size is reduced by devising the splined shaft 5 and its peripheral structure.

[0028] From the perspective of shortening the substantial axial length of the coupling mechanism 50, a part of the extension shaft 5 is made to enter inside the reduction unit 10. Specifically, as shown in FIG. 1, the reduction gear 100 surrounds the input shaft 20 and has an input shaft surrounding member that is positioned radially inward with respect to the internal teeth of the internal gear. In the example of FIG. 1, the input shaft surrounding member is exemplified by the second carrier 36. In the reduction gear 100, a portion 59 that is on the side opposite to the motor side with respect to the seal arrangement portion 53 of the extension shaft 5 overlaps with the second carrier 36, which is the input shaft surrounding member, when viewed radially. In this case, the substantial axial length of the coupling mechanism 50 can be shortened. In other words, making a part of the extension shaft 5 enter inside the reduction unit 10 can be said to be one measure to reduce the increase in size of the above-described device. From the same perspective, the reduction gear 100 may be configured such that an eccentric bearing 16 disposed between the external gear 13 of the second carrier 36 and the input shaft 20 and a portion protruding toward the motor side from the second bearing 40 overlap with the seal arrangement portion 53 in the radial direction. Note that the portion that overlaps with the seal arrangement portion 53 of the second carrier 36 in the radial direction may be a portion that protrudes radially inward and positions the second bearing 40 of the second carrier 36. The second carrier 36 will be described later.

[0029] The end portion 56 on the side opposite to the motor side is an end portion disposed on the side opposite to the motor side of the surrounding portion 51 and is a portion that contacts the end portion 27 on the motor side of the input shaft 20. A plurality of bolt holes 57 that are arranged at a predetermined interval in the circumferential direction and penetrate in the axial direction are provided at positions offset from the central axis line La in the end portion 56 on the side opposite to the motor side. Although there is no limitation on the number of bolt holes 57, in this example, six bolt holes 57 are provided every 60°. By screwing the bolt B2 from the motor side through the bolt hole 57 into the bolt connection portion 29 of the input shaft 20, the extension shaft 5 is fixed to the input shaft 20.

[0030] Refer to the enlarged view A of FIG. 1. It is conceivable that the lubricant of the second bearing 40 leaks from between the input shaft 20 and the extension shaft 5 through the bolt hole 57. Therefore, in the embodiment, leakage prevention means for reducing the leakage of the lubricant is provided between the input shaft 20 and the extension shaft 5. Known means can be used as the leakage prevention means. In this example, a liquid gasket 17 is applied to the end face on the motor side of the input shaft 20 or the end face on the side opposite to the motor of the extension shaft 5. By applying the gasket 17, the leakage of the lubricant can be reduced.

[0031] As shown in FIG. 2, the tightening portion 54 is a cylindrical portion surrounding the connecting hole 52 and is continuously provided on the motor side of the surrounding portion 51. When the outer peripheral surface of the tightening portion 54 is tightened by the clamp ring 7, it has elasticity to bend inward. The tightening portion 54 bends inward and presses against the outer peripheral surface of the motor shaft 12, and the extension shaft 5 is fixed to the motor shaft 12 by the frictional force between the tightening portion 54 and the motor shaft 12. When the clamp ring 7 is loosened, the tightening portion 54 moves away from the motor shaft 12, and the extension shaft 5 becomes non-fixed with respect to the motor shaft 12.

[0032] The shape of the tightening portion 54 can be set by experiment or simulation so as to obtain a desired elasticity and a desired frictional force. In order to adjust the elasticity, the radial thickness of the tightening portion 54 may be thinner than the radial thickness of the surrounding portion 51, and the outer diameter of the tightening portion 54 may be smaller than that of the surrounding portion 51. In order to adjust the elasticity, two slits 55 extending in the axial direction are provided at 180° intervals in the circumferential direction in the tightening portion 54. The slit 55 has a semi-elliptical shape extending from the motor-side end of the tightening portion 54 to the side opposite to the motor. The number and shape of the slits 55 can be set so as to obtain a desired elasticity.

[0033] The secondary shaft 5 is preferably coaxially connected to the input shaft 20. Therefore, in the embodiment, the input shaft 20 has a hollow portion 28 that is recessed axially from the motor-side end portion 27, and the secondary shaft 5 has a convex portion 58 that fits into the hollow portion 28 in an inlay manner. In this case, the coaxial performance between the secondary shaft 5 and the input shaft 20 is improved. The convex portion 58 is a cylindrical protrusion that protrudes from the anti-motor-side end portion 56 toward the anti-motor side. The shape of the convex portion 58 may be set by experiment or simulation so as to ensure the desired coaxial performance between the secondary shaft 5 and the input shaft 20.

[0034] Referring to FIGS. 1 and 3, the clamping ring 7 will be described. FIG. 3 is a front view of the clamping ring 7. The clamping ring 7 generates a large frictional force between the motor shaft 12 or the adapter ring 6 and the tightening portion 54 by tightening the tightening portion 54 inward from the outer periphery, and firmly connects the secondary shaft 5 and the motor shaft 12. The clamping ring 7 is a C-shaped ring member in which a part of the hollow ring is cut out, and a gap portion 73 is provided in the cutout portion. The clamping ring 7 has an outer peripheral surface portion 72 and an inner peripheral surface portion 76, and has a groove 74 that extends axially at a position 180° away in the circumferential direction from the gap portion 73 on the inner peripheral surface portion 76. The shape of the clamping ring 7 including the groove 74 can be set by experiment or simulation from the viewpoint of obtaining the desired elasticity.

[0035] As shown in FIG. 3, the clamping ring 7 is provided with a bolt hole 75 for accommodating a bolt B3 for adjusting the gap of the gap portion 73 and a female screw portion 77 that engages with the bolt B3. The bolt hole 75 and the female screw portion 77 communicate along a straight line Lb that is in a twisted position with respect to the central axis line La. When the clamping ring 7 is in a predetermined rotational position, the bolt hole 75, the female screw portion 77, the tool hole 85, and the tap hole 86 communicate along the straight line Lb. In this state, the bolt B3 can be rotated by a tool that enters through these holes. When the bolt B3 is tightened, the clamping ring 7 can narrow the gap of the gap portion 73 and tighten the tightening portion 54 inward.

[0036] Referring to FIGS. 1 and 4, the motor shaft 12 and the adapter 6 will be described. FIG. 4 is a cross-sectional side view of the adapter 6. The adapter 6 is an adapter that adapts the motor shaft 12 with a small shaft diameter to the extension shaft 5. Therefore, it becomes unnecessary when the shaft diameter of the motor shaft is thick. In the example of FIG. 1, the motor shaft 12 is a tapered shaft whose diameter gradually decreases toward the tip side, and has a male screw portion 66 protruding from the tip.

[0037] The adapter 6 is a hollow cylindrical member having a cylindrical outer peripheral surface portion 62 and an inner peripheral surface portion 64, and a key groove 65 extending in the axial direction is formed in the inner peripheral surface portion 64. The inner peripheral surface portion 64 has a taper that conforms to the taper of the motor shaft 12. The motor shaft 12 is connected to the adapter 6 by a half-moon key 68. As this connecting means, known connecting means can be used instead of the half-moon key connection. With the motor shaft 12 connected to the adapter 6, by screwing a set screw such as a hexagonal socket nut 67 onto the male screw portion 66, the respective tapers of the motor shaft 12 and the inner peripheral surface portion 64 are in close contact, generating a strong fastening force.

[0038] Referring to FIGS. 1, 2, and 5, the input shaft 20 will be described. FIG. 5 is a side view showing the input shaft 20. The input shaft 20 is rotated around the rotation center line La by the rotational power input from the motor shaft 12. The input shaft 20 is an eccentric shaft having a plurality of eccentric portions 23 for swinging the external gear 13, and may be referred to as a crank shaft. The axis of the eccentric portion 23 is eccentric with respect to the rotation center line La of the input shaft 20. In the present embodiment, three eccentric portions 23 are provided, and the eccentric phases of the adjacent eccentric portions 23 are shifted by 120°.

[0039] The input shaft 20 has a first shaft portion 22 provided on the side opposite to the motor side of the eccentric portion 23, a protruding shaft portion 21 provided on the side opposite to the motor side of the first shaft portion 22, and a second shaft portion 26 provided on the motor side of the eccentric portion 23. The second shaft portion 26 is also the shaft end portion 18 on the motor side of the input shaft 20. Further, the input shaft 20 has an end portion 27 on the motor side, a hollow portion 28, and a bolt connection portion 29.

[0040] The hollow portion 28 is a circular hole formed from the motor-side end portion 27 of the input shaft 20 along the center of the input shaft 20 toward the non-motor side, and the convex portion 58 of the extension shaft 5 is press-fitted therein. The shape of the hollow portion 28 may be set by experiment or simulation so as to ensure the desired coaxial performance between the extension shaft 5 and the input shaft 20.

[0041] The bolt connection portion 29 is a female screw hole formed from the motor-side end portion 27 of the input shaft 20 toward the non-motor side. The bolt connection portion 29 is provided at a position corresponding to the bolt hole 57 of the extension shaft 5. In this example, six bolt connection portions 29 are provided at intervals of 60° in the circumferential direction. The input shaft 20 is fixed to the extension shaft 5 by screwing the bolt B2 from the connection hole 52 through the bolt hole 57 into the bolt connection portion 29.

[0042] In the manufacturing process of the input shaft 20, these portions are polished in order to finish the first shaft portion 22, the three eccentric portions 23, and the second shaft portion 26 with high precision. For this purpose, it is conceivable to provide an extension portion obtained by extending the second shaft portion 26 toward the motor side and chucking this extension portion to polish these portions. However, in this case, there is a problem that the extension shaft 5 shifts toward the motor side by the length of the extension portion and the connection mechanism 50 increases in size in the axial direction. Therefore, in the input shaft 20 of the embodiment, a protruding shaft portion 21 is provided on the non-motor side of the first shaft portion 22. In this case, it is more advantageous for miniaturization in the axial direction than extending the second shaft portion 26 toward the motor side. Further, the first shaft portion 22, the eccentric portions 23, and the second shaft portion 26 can be easily polished. In other words, providing the protruding shaft portion 21 can be said to be one of the measures for reducing the size increase of the above-described device.

[0043] As shown in Fig. 1, the speed reducer 100 has a first bearing 39 that supports the input shaft 20 on the side opposite to the motor, and a second bearing 40 that supports the input shaft 20 on the motor side with respect to the first bearing 39. The first bearing 39 and the second bearing 40 are ball bearings. The input shaft 20 has a protruding shaft portion 21 that protrudes from the first bearing 39 toward the side opposite to the motor. The protruding shaft portion 21 functions as a shaft portion for chucking. If the protruding shaft portion 21 is short, the chuck may come off during machining. Therefore, the protruding shaft portion 21 of the embodiment protrudes from the first bearing 39 toward the side opposite to the motor. In this case, the protruding shaft portion 21 can be made longer.

[0044] It is convenient to have an axial positioning portion when chucking the protruding shaft portion 21. Therefore, the outer diameter D21 of the protruding shaft portion 21 of the embodiment is smaller than the outer diameter D22 of the first shaft portion 22, which is a portion continuous with the protruding shaft portion 21 toward the motor side. In this case, a step is formed between the protruding shaft portion 21 and the first shaft portion 22, and this step can be used as a positioning portion during chucking.

[0045] Also refer to the enlarged view B of Fig. 1. As described above, the speed reducer 100 has a bolt B2 that axially connects the input shaft 20 and the countershaft 5. If the head H2 of the bolt B2 interferes with the connecting hole 52, it may be an obstacle when screwing in the bolt B2 and it may not be tightened sufficiently. Therefore, in the embodiment, as shown in the enlarged view B of Fig. 1, a gap G1 is provided between the outer peripheral surface of the head H2 of the bolt B2 and the inner peripheral surface of the connecting hole 52. In other words, the shape of the six bolts B2 and the pitch circle diameter of the bolts B2 are determined so as to obtain a gap G1 of a desired size. From the viewpoint of avoiding problems such as insufficient tightening, the gap G1 is preferably 0.1 mm or more, and is set to 0.3 mm in the embodiment.

[0046] The gap between the inner peripheral surface of the connecting hole 52 and the outer peripheral surface of the member surrounded by the connecting hole 52 becomes smaller during clamping than during non-clamping. Along with this, it is conceivable that the gap G1 during clamping also becomes smaller. Therefore, the gap G1 is set to be larger than the gap between the inner peripheral surface of the connecting hole 52 and the outer peripheral surface of the member surrounded by the connecting hole 52 during non-clamping. In this case, interference between the head H2 and the connecting hole 52 during clamping can be avoided. That is, the diameter of the portion surrounding the heads H2 of the plurality of bolts B2 is smaller than the diameter of the outer peripheral surface of the member surrounded by the connecting hole 52 and clamped to the tightening portion 54. The member to be clamped is the adapter ring 6 shown in FIG. 2, the motor shaft 112 shown in FIG. 6 described later, and the like.

[0047] The first shaft portion 22 is supported by the first carrier 35 via the first bearing 39, and the second shaft portion 26 is supported by the second carrier 36 via the second bearing 40. The second shaft portion 26 is a cylindrical portion having the same diameter as the first shaft portion 22.

[0048] Referring to FIG. 1, other configurations of the speed reduction unit 10 will be described. The casing 80 has a cylindrical shape surrounding the speed reduction unit 10, and an internal gear 41 is provided on the inner peripheral surface. The external gears 13 are provided individually corresponding to the respective eccentric portions 23. The external gears 13 are swingably incorporated on the outer periphery of the eccentric portions 23 via eccentric bearings 16 which are roller bearings. The external gears 13 are internally meshed with the internal gear 41 while swinging respectively. Wave-shaped teeth are formed on the outer periphery of the external gears 13, and by moving while these teeth are in contact with the internal gear 41, the external gears 13 can swing within a plane having the central axis as the normal line.

[0049] The internal gear 41 of the present embodiment has an internal gear main body 42 integrally provided on the inner peripheral side of the casing 80, and a plurality of external pins 43 arranged in pin grooves formed at predetermined intervals in the circumferential direction on the inner peripheral surface of the internal gear main body 42. The external pins 43 are columnar pin members rotatably supported in the pin grooves of the internal gear main body 42. The external pins 43 constitute the internal teeth of the internal gear 41. The number of external pins 43 of the internal gear 41 is the number of internal teeth, which is one more than the number of external teeth of the external gear 13.

[0050] A plurality of inner pin holes 45 are formed in the external gear 13 at positions offset from its axis. Inner pins 48 penetrate the inner pin holes 45. A cylindrical sleeve 49 is disposed on the outer periphery of the inner pins 48. The inner pins 48 contribute to the transmission of power between the carriers 35, 36 and the external gear 13.

[0051] The carriers 35, 36 have a hollow ring shape. The first carrier 35 is disposed on the side of the external gear 13 opposite to the motor side, and the second carrier 36 is disposed on the side of the external gear 13 on the motor side. The carriers 35, 36 are rotatably supported by the casing 80 via main bearings 37. The carriers 35, 36 rotatably support the input shaft 20 via first bearings 39 and second bearings 40. In this example, the main bearing 37 is an angular ball bearing disposed between the casing 80 and the carriers 35, 36.

[0052] The inner pins 48 extend axially from the first carrier 35 toward the second carrier 36. The carriers 35, 36 are connected to each other by screwing a bolt B1 through a through hole provided in the second carrier 36 into a tapped hole provided at the end of the inner pin 48.

[0053] In this example, the casing 80 is a fixed member fixed to a mating member (not shown), and the first carrier 35 is an output member that outputs rotational power to a driven member (not shown). The carrier may be used as the fixed member and the casing may be used as the output member.

[0054] Next, with reference to FIG. 6, an example of connecting another motor 111 to the speed reduction device 100 will be described. FIG. 6 is a cross-sectional view showing a state in which another motor 111 is connected to the speed reduction device 100. The motor shaft 112 of the motor 111 has a larger outer diameter than the motor shaft 12 of the motor 11. Therefore, the extension shaft 5 can connect the motor shaft 112 to the input shaft 20 without using the adapter ring 6. Thus, the speed reduction device 100 of the present embodiment can also be connected to a motor shaft having a larger shaft diameter than the input shaft 20 within the range of the aperture diameter of the connecting hole 52.

[0055] Next, with reference to FIGS. 1-4, an assembly method of the speed reduction device 100 will be described. First, prepare the speed reduction unit 10 with the countershaft 5 fixed thereto, the cylindrical portion 8 with the seal member S2 attached thereto, and the motor 11 with the adapter 6 attached to the motor shaft 12. Next, while fitting the seal member S2 onto the countershaft 5, fix the cylindrical portion 8 to the speed reduction unit 10. Next, fit the clamping ring 7 onto the countershaft 5. Next, while fitting the motor shaft 12 together with the adapter 6 onto the countershaft 5, fix the motor 11 to the cylindrical portion 8. Next, rotate the clamping ring 7 so that the bolt hole 75 communicates with the tool hole 85, and insert a tool through these holes up to the bolt B3. Next, tighten the bolt B3 with the tool to tighten the tightening portion 54 inward to connect the countershaft 5 and the adapter 6. By these steps, the speed reduction unit 10 is connected to the motor 11. This method is an example, and various modifications are possible.

[0056] Next, with reference to FIG. 1, the speed reduction operation of the speed reduction unit 10 will be described. When rotational power is transmitted from the motor shaft 12 to the input shaft 20 via the countershaft 5, the eccentric portion 23 of the input shaft 20 rotates around the rotation center line passing through the input shaft 20, and the external gear 13 swings due to the eccentric portion 23. At this time, the external gear 13 swings such that its own axis rotates around the rotation center line of the input shaft 20. When the external gear 13 swings, the meshing position of the external pin 43 of the external gear 13 and the internal gear 41 shifts sequentially. As a result, every time the input shaft 20 makes one rotation, rotation of either the external gear 13 or the internal gear 41 corresponding to the difference between the number of teeth of the external gear 13 and the number of external pins 43 of the internal gear 41 occurs. In the present embodiment, the external gear 13 rotates, and a speed-reduced rotation is output from the first carrier 35. When the first carrier 35 rotates, a driven member (not shown) connected to the first carrier 35 is rotationally driven.

[0057] The features of the speed reduction device 100 configured as described above will be described. The speed reduction device 100 of the present embodiment is an eccentric swing type speed reduction device including an input shaft 20 which is an eccentric body shaft, and a countershaft 5 connected to the input shaft 20. The countershaft 5 has a connection hole 52 to which the motor shaft 12 is connected. The outer diameter D51 of the surrounding portion 51 surrounding the connection hole 52 of the countershaft 5 is larger than the outer diameter of the shaft end portion 18 on the motor side of the input shaft 20.

[0058] According to this configuration, since the outer diameter D51 of the surrounding portion 51 is larger than the outer diameter D18 of the shaft end portion 18, the connecting hole can be made larger when provided in the coupling shaft 5 than when provided in the input shaft 20. For this reason, the outer diameter range of the motor shaft 12 that can be connected can be widened.

[0059] The above is the description of the first embodiment.

[0060] [Second Embodiment] With reference to FIGS. 7 and 2, the speed reduction device 200 according to the second embodiment of the present invention will be described. FIG. 7 is a cross-sectional view schematically showing the speed reduction device 200. This figure shows the speed reduction device 200 in a state incorporated in the device unit 1. In the description of the second embodiment, the same or equivalent components and members as those in the first embodiment are denoted by the same reference numerals. The description overlapping with the first embodiment will be omitted as appropriate, and the configuration different from the first embodiment will be mainly described. The speed reduction device 200 of the second embodiment is different from the speed reduction device 100 of the first embodiment in that the reduction unit 10 includes a deflection meshing type speed reducer having a cylindrical external gear, and the other configurations are the same.

[0061] The device unit 1 includes a motor 11 having a motor shaft 12, a reduction unit 10 that reduces the rotation of the motor shaft 12 and outputs it, and a coupling mechanism 50 that couples the motor 11 to the reduction unit 10. The coupling mechanism 50 mainly includes a coupling shaft 5, an adapter ring 6, a clamp ring 7, and a cylindrical portion 8. The speed reduction device 200 has a configuration in which the coupling shaft 5 is fixed to the input shaft 20 of the reduction unit 10.

[0062] The speed reduction device 200 is a speed reduction device including an input shaft 20 that is an oscillation body shaft and a coupling shaft 5 connected to the input shaft 20. As shown in FIG. 2, the coupling shaft 5 has a connection hole 52 to which the motor shaft 12 is connected, and the outer diameter D51 of the surrounding portion 51, which is a surrounding portion surrounding the connection hole 52 of the coupling shaft 5, is larger than the outer diameter D18 of the shaft end portion 18 on the motor side of the input shaft 20.

[0063] In the example of FIG. 7, the wave deceleration device 200 is mainly a cup-shaped flexural meshing type deceleration device including an external gear 13 that is flexurally deformed by an input shaft 20 which is an oscillation body axis, an internal gear 41 that meshes with the external gear 13, and a main bearing 37 that supports a casing 84 provided with the internal gear 41.

[0064] The above is the description of the second embodiment. The second embodiment has the same operations and effects as the first embodiment.

[0065] The present invention has been described based on the embodiments. These embodiments are illustrative, and it is understood by those skilled in the art that various modifications and changes are possible within the scope of the claims of the present invention, and such modified examples and changes are also within the scope of the claims of the present invention. Therefore, the descriptions and drawings in this specification should be treated as illustrative rather than restrictive.

[0066] (Modification example) Hereinafter, a modification example will be described. In the drawings and descriptions of the modification example, the same reference numerals are given to the components and members that are the same as or equivalent to those in the embodiment. Descriptions overlapping with the embodiment are omitted as appropriate, and the configurations different from the embodiment will be mainly described.

[0067] In the above description, an example in which the input shaft surrounding member is the second carrier 36 is shown, but the present invention is not limited to this. For example, the input shaft surrounding member may include, in addition to the carrier, the internal tooth portion of the internal gear, an external gear, etc.

[0068] In the above description, an example in which the external teeth of the external gear 13 and the internal teeth of the internal gear 41 in FIG. 7 do not overlap with the seal arrangement portion 53 is shown, but the present invention is not limited to this. For example, the external teeth of the external gear 13 or the internal teeth of the internal gear 41 may extend toward the motor side so as to overlap with the seal arrangement portion 53.

[0069] In the above description, an example in which two slits 55 are provided in the tightening portion 54 is shown, but the present invention is not limited to this. The number of slits in the tightening portion may be three or more.

[0070] In the above description, an example in which the speed reduction unit 10 includes three external gear wheels 13 has been shown, but the present invention is not limited to this. The speed reduction unit may include two or less or four or more external gear wheels.

[0071] In the above description, an example in which the harmonic speed reduction device 200 includes a cylindrical flexure engagement type speed reducer has been shown, but the present invention is not limited to this. The harmonic speed reduction device may include a cup type or a silk hat type flexure engagement type speed reducer.

[0072] Each of these modifications exhibits the same operations and effects as the embodiment.

[0073] Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present invention. The new embodiment resulting from the combination has the combined effects of the embodiments and modifications being combined.

Explanation of Reference Numerals

[0074] 5 intermediate shaft, 11 motor, 12 motor shaft, 18 shaft end, 20 input shaft, 21 protruding shaft portion, 27 end, 28 hollow portion, 35 first carrier, 36 second carrier, 39 first bearing, 40 second bearing, 41 internal gear, 50 connecting mechanism, 51 surrounding portion, 52 connecting hole, 53 seal arrangement portion, 58 convex portion, 59 anti-motor side portion, 100 eccentric swing type speed reduction device, 200 harmonic speed reduction device.

Claims

1. An eccentric swing type reduction gear including an input shaft which is an eccentric body shaft and a relay shaft connected to the input shaft, the relay shaft has a connection hole to which a motor shaft is connected, and an eccentric swing type reduction gear in which an outer diameter of an surrounding portion surrounding the connection hole of the relay shaft is larger than an outer diameter of a shaft end portion on the motor side of the input shaft.

2. A wave reduction gear including an input shaft which is an oscillation body shaft and a relay shaft connected to the input shaft, the relay shaft has a connection hole to which a motor shaft is connected, and a wave reduction gear in which an outer diameter of an surrounding portion surrounding the connection hole of the relay shaft is larger than an outer diameter of a shaft end portion on the motor side of the input shaft.

3. The input shaft has a hollow portion recessed axially from an end portion on the motor side, and the relay shaft has a convex portion that fits into the hollow portion in an inlay fit, according to the eccentric swing type reduction gear described in Claim 1.

4. The relay shaft has a seal arrangement portion where a seal member is arranged, and an outer diameter of the seal arrangement portion is larger than an outer diameter of the input shaft, according to the eccentric swing type reduction gear described in Claim 1.

5. It has an input shaft surrounding member that surrounds the input shaft and is located radially inside the internal teeth of the internal gear, and a portion of the relay shaft on the side opposite to the motor side of the seal arrangement portion overlaps with the input shaft surrounding member when viewed radially, according to the eccentric swing type reduction gear described in Claim 4.

6. It has a first bearing that supports the input shaft on the side opposite to the motor side and a second bearing that supports the input shaft on the motor side of the first bearing, and the input shaft has a protruding shaft portion that protrudes from the first bearing to the side opposite to the motor side, according to the eccentric swing type reduction gear described in Claim 1.

7. An outer diameter of the protruding shaft portion is smaller than an outer diameter of a portion continuous with the protruding shaft portion on the motor side, according to the eccentric swing type reduction gear described in Claim 6.

8. having a bolt that axially connects the input shaft and the relay shaft, The eccentric swing type reduction device according to claim 1, wherein a gap is provided between an outer peripheral surface of a head portion of the bolt and an inner peripheral surface of the connection hole.

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