Eccentric oscillating gear system

Abstract

This technology provides an advantage in reducing manufacturing costs when incorporating pin bodies into eccentric oscillating gear systems. [Solution] The system comprises a crankshaft 14 having an eccentric portion 12, a rocking member 16 that is rocked by the eccentric portion 12, an external gear group 18 that rocks together with the rocking member 16, an internal gear 20 that meshes with the external gear group 18, a first lateral member 22 positioned on one axial side with respect to the rocking member 16, and a pin body 46 that synchronizes the rotational component of the rocking member 16 with the first lateral member 22, with contact being made with a first recess 50 provided in the rocking member 16 and a second recess 52 provided in the first lateral member 22, respectively, wherein the pin body 46 is rotatably provided inside the first recess 50 and the second recess 52, respectively.

Description

Technical Field

[0001] The present disclosure relates to an eccentric swing type gear device.

Background Art

[0002] Patent Document 1 discloses an eccentric swing type gear device including a crankshaft having an eccentric portion, an external gear swung by the eccentric portion, an internal gear meshing with the external gear, a first side member disposed on one axial side of the external gear, and a pin body for synchronizing the rotation component of the external gear and the first side member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the eccentric swing type gear device of Patent Document 1, the first side member and the pin body are integrally formed. In this case, in incorporating the pin body into the gear device, the first side member and the pin body are obtained by machining such as milling using an end mill or the like, and the manufacturing cost becomes very high.

[0005] Therefore, one object of the present disclosure is to provide a technique for advantageously reducing the manufacturing cost in incorporating a pin body into an eccentric swing type gear device.

Means for Solving the Problems

[0006] The eccentric oscillating gear device of the present disclosure comprises a crankshaft having an eccentric portion, an oscillating member that is oscillated by the eccentric portion, a group of external teeth that oscillates together with the oscillating member, an internal gear that meshes with the group of external teeth, a first lateral member positioned on one axial side with respect to the oscillating member, and a pin body that contacts a first recess provided in the oscillating member and a second recess provided in the first lateral member, respectively, and synchronizes the rotational component of the oscillating member with the first lateral member, wherein the pin body is rotatably provided inside the first recess and the second recess, respectively. [Effects of the Invention]

[0007] According to this disclosure, it is possible to reduce manufacturing costs when incorporating pin bodies into gear devices. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side view showing a partial cross-section of the gear mechanism of the first embodiment. [Figure 2] This is a magnified view of a portion of Figure 1. [Figure 3] This is a schematic cross-sectional view showing a portion of the cross-section passing through the line III-III in Figure 2. [Figure 4] This is a schematic cross-sectional view showing a portion of the cross-section passing through the line IV-IV in Figure 2. [Figure 5] Figure 5(A) is a schematic diagram showing the configuration around the first roller, and Figure 5(B) is a schematic diagram showing the various elements in operation from the state shown in Figure 5(A). [Figure 6] This figure shows the gear apparatus of the second embodiment viewed from the same viewpoint as in Figure 2. [Figure 7] This is a view of the gear apparatus of the third embodiment from the same viewpoint as in Figure 2. [Figure 8] This is a schematic cross-sectional view showing a portion of the cross-section passing through line VIII-VIII in Figure 7. [Figure 9] This figure shows the gear apparatus of the fourth embodiment, viewed from the same viewpoint as in Figure 2. [Figure 10]This is a schematic cross-sectional view showing a portion of the cross-section passing through line XX in Figure 9. [Figure 11] This is a view of the gear apparatus of the fifth embodiment from the same viewpoint as in Figure 2. [Modes for carrying out the invention]

[0009] Embodiments for implementing the eccentric oscillating gear device (hereinafter also simply referred to as the gear device) of this disclosure will be described below. The same or equivalent elements are denoted by the same reference numerals, and redundant explanations will be omitted. In each drawing, components are omitted, enlarged, or reduced as appropriate for the sake of explanation. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0010] (First Embodiment) Refer to Figures 1 and 2. The gear device 10 comprises a crankshaft 14 having an eccentric portion 12, a rocking member 16 that is rocked by the eccentric portion 12, an external gear group 18 that rocks together with the rocking member 16, an internal gear 20 that meshes with the external gear group 18, and a first lateral member 22 that is positioned on one axial side (left side in the figure) relative to the rocking member 16. The gear device 10 also comprises a second lateral member 24 that is positioned on the other axial side (right side in the figure) relative to the rocking member 16, a casing 26 positioned radially outward of the rocking member 16, and an eccentric bearing 28 positioned between the rocking member 16 and the eccentric portion 12.

[0011] In this embodiment, an example is described in which the input member to which rotation is input from an external drive source is a crankshaft 14, and the output member to which rotation is output to an external driven device is a first lateral member 22. The drive source is, for example, a motor, gear motor, engine, etc. The driven device is, for example, at least a part of various machines such as (1) industrial machinery such as machine tools and construction machinery, (2) robots such as industrial robots and service robots, (3) transport equipment such as conveyors, and (4) vehicles.

[0012] In this embodiment, during the operation of the gear device 10, while the swing member 16 swings, the first side member 22 and the internal gear 20 rotate relative to each other around the central axis C10 of the gear device 10. In this specification, the direction along the central axis C10 of this gear device 10 is simply referred to as the axial direction, and the radial direction and circumferential direction with respect to the central axis C10 are also simply referred to as the radial direction and circumferential direction, respectively. Further, the circumferential direction and radial direction with respect to the center line C12 of the eccentric portion 12 are referred to as the "circumferential direction and radial direction of the eccentric portion 12". The central axis C10 of the gear device 10 is also the central axis of the internal gear 20.

[0013] The crankshaft 14 includes at least one eccentric portion 12 and a shaft portion 14a provided on at least one axial side with respect to the eccentric portion 12. In addition to this, the crankshaft 14 may include a hollow portion 14b that penetrates the crankshaft 14 in the axial direction. The crankshaft 14 of this embodiment includes only a single eccentric portion 12. The eccentric portion 12 of this embodiment is integrally provided by the same member as the shaft portion 14a, but may be provided separately from the shaft portion 14a. The eccentric portion 12 has a circular shape that is eccentric by an eccentricity amount e with respect to the rotation center line C14 of the crankshaft 14. The eccentric portion 12 swings the swing member 16 by rotating around the rotation center line C14 of the crankshaft 14. Here, the swing of the swing member 16 means that the swing member 16 moves such that the center line C16 of the swing member 16 revolves around the central axis C10 of the gear device 10.

[0014] Refer to FIG. 2. The swing member 16 has a disk shape that is continuous in the circumferential direction of the eccentric portion 12. The swing member 16 includes a bearing hole 16a in which an eccentric bearing 28 is disposed inside.

[0015] The external tooth group 18 includes a plurality of external tooth portions 18a disposed in the circumferential direction of the eccentric portion 12. The external tooth group 18 of this embodiment is integrally provided on the outer peripheral portion of the swing member 16 by the same member as the swing member 16 and can swing together with the swing member 16. In addition to this, the external tooth group 18 may be provided separately from the swing member 16 as will be described later.

[0016] The internal gear 20 of this embodiment is provided in the casing 26. In addition to this, the internal gear 20 may be provided on the second side member 24 connected to the casing 26 as will be described later. In either case, the internal gear 20 will be integrated with the casing 26. Here, "integration" means that the two elements mentioned (here, the internal gear 20 and the casing 26) are provided so as not to be relatively rotatable with respect to each other.

[0017] The internal gear 20 includes an internal gear main body 20a and a plurality of internal teeth 20b provided on the inner peripheral portion of the internal gear main body 20a and meshing with the external tooth group 18. The internal gear main body 20a may also serve as the casing 26 as in this embodiment, or may also serve as the second side member 24 as will be described later. The plurality of internal teeth 20b in this embodiment are integrally provided by the same member as the internal gear main body 20a. In addition to this, the plurality of internal teeth 20b may be constituted by a plurality of pins rotatably supported by the internal gear main body 20a.

[0018] The external tooth group 18 and the internal gear 20 constitute a gear mechanism 30 that converts the swinging motion of the swinging member 16 into a rotational motion of the swinging member 16 or the internal gear 20 when the swinging member 16 swings due to the rotation of the crankshaft 14. For example, the plurality of external teeth 18a may have a trochoid tooth profile, and the plurality of internal teeth 20b may have a trochoid tooth profile. The combination of the tooth profiles of the external teeth 18a and the internal teeth 20b is not particularly limited, and various other combinations of tooth profiles may be adopted.

[0019] The first side member 22 is an annular member continuous around the central axis C10 of the gear device 10. A driven device is connected to the first side member 22 serving as an output member by bolts or the like. The first side member 22 of this embodiment functions as a carrier disposed inside the casing 26.

[0020] The second side member 24 is an annular member continuous around the central axis C10 of the gear device 10. The second side member 24 of this embodiment covers the swinging member 16 from the other side in the axial direction. The second side member 24 of this embodiment functions as a casing connecting member connected to the casing 26 by bolts or the like not shown.

[0021] The casing 26 houses at least the oscillating member 16. The casing 26 in this embodiment is composed of a plurality of casing members 26a, 26b connected by bolts or the like. The plurality of casing members 26a, 26b include a first casing member 26a and a second casing member 26b arranged on one axial side of the first casing member 26a.

[0022] A main bearing 32 is positioned between the first lateral member 22 and the casing 26. In this embodiment, the main bearing 32 is a cross roller bearing, but its type is not particularly limited. In this embodiment, the outer ring of the main bearing 32 is also the casing 26, and the inner ring of the main bearing 32 is also the first lateral member 22. In addition, the main bearing 32 may also be equipped with a dedicated outer ring and inner ring.

[0023] In addition, the gear unit 10 includes a first crankshaft bearing 34 positioned between the shaft portion 14a of the crankshaft 14 and the first lateral member 22, and a second crankshaft bearing 36 positioned between the shaft portion 14a of the crankshaft 14 and the second lateral member 24. Note that one of the first crankshaft bearing 34 and the second crankshaft bearing 36 may be omitted, and the number of the other may be increased to two or more.

[0024] In this embodiment, the first crankshaft bearing 34 is a full-roller bearing without a cage. The outer ring of the first crankshaft bearing 34 is also the inner circumferential surface of the first lateral member 22, and the inner ring of the first crankshaft bearing 34 is also the outer circumferential surface of the crankshaft 14. The type of the first crankshaft bearing 34 is not limited to this, and it may be provided with a dedicated outer ring and inner ring.

[0025] In this embodiment, the second crankshaft bearing 36 is a full-roller bearing without a cage. The outer ring of the second crankshaft bearing 36 is also the inner circumferential surface of the second lateral member 24, and the inner ring of the second crankshaft bearing 36 is also the outer circumferential surface of the crankshaft 14. The inner circumferential surface of the second lateral member 24 is provided with an outer ring-side rolling surface 36a on which the rolling elements of the second crankshaft bearing 36 roll. The type of the second crankshaft bearing 36 is not limited to this, and it may be provided with a dedicated outer ring and inner ring.

[0026] Refer to Figures 2 and 3. In Figure 3, the external gear group 18 of the rocking member 16 is omitted. The eccentric bearing 28 supports the rocking member 16 so that it can rotate relative to the eccentric portion 12 of the crankshaft 14. The eccentric bearing 28 comprises a plurality of rolling elements 40 arranged in the circumferential direction of the eccentric portion 12, and an outer ring 42 and an inner ring 44 on which the plurality of rolling elements 40 roll. The eccentric bearing 28 in this embodiment is a roller bearing without a cage that is provided between the plurality of rolling elements 40 and holds the positions of the plurality of rolling elements 40, and the rolling elements 40 are rollers.

[0027] In this embodiment, the eccentric bearing 28 does not have a dedicated inner ring 44, and the outer circumferential surface of the eccentric portion 12 also serves as the inner ring 44. Alternatively, the eccentric bearing 28 may have a dedicated inner ring 44 that is separate from and integrated with the eccentric portion 12.

[0028] In this embodiment, the eccentric bearing 28 does not have a dedicated outer ring 42; the inner circumferential surface of the bearing hole 16a of the oscillating member 16 serves as the outer ring 42. Alternatively, the eccentric bearing 28 may have a dedicated outer ring 42 that is separate from and integrated with the oscillating member 16.

[0029] Multiple fitting grooves 42a are formed on the inner circumferential surface of the outer ring 42, into which the rolling elements 40 are fitted so as to rotate freely. The multiple fitting grooves 42a extend along the axial direction. The multiple fitting grooves 42a are arc-shaped, recessed radially outward from the eccentric portion 12 on the inner circumferential surface of the outer ring 42, and have an arc shape with a radius slightly larger than the radius of the rolling elements 40. The multiple fitting grooves 42a are arranged in the circumferential direction of the eccentric portion 12 such that the centers of the arcs formed by the fitting grooves 42a are located on a common virtual circle Ca. By fitting into the fitting grooves 42a, the relative positions of the multiple rolling elements 40 are maintained, and the rolling elements 40 become able to swing together with the oscillating member 16. Swinging of the rolling elements 40 together with the oscillating member 16 means that the rolling elements 40 move in the same direction and at the same speed as the center line C16 of the oscillating oscillating member 16. At this time, the rolling element 40 revolves around the center line C16 of the rocking member 16 with the same orbital component as the rotational component of the rocking member 16.

[0030] The inner ring 44 has an inner ring side rolling surface 44a on which the rolling elements 40 roll. The inner ring side rolling surface 44a is continuous in an annular manner in the circumferential direction of the eccentric portion 12. The outer ring 42 has an outer ring side rolling surface 42b on which the rolling elements 40 roll. In this embodiment, the outer ring side rolling surface 42b is composed of the inner circumferential surfaces of each of the multiple fitting grooves 42a and is not continuous in an annular manner in the circumferential direction of the eccentric portion 12. Consider the case in which the rocking member 16 rotates relative to the eccentric portion 12 of the crankshaft 14. In this case, the rolling elements 40 roll on the inner ring side rolling surface 44a of the eccentric bearing 28, mainly with rolling contact, and on the inner circumferential surface (outer ring side rolling surface 42b) of the fitting groove 42a, mainly with sliding contact.

[0031] Refer to Figure 2. The gear mechanism 10 described above includes at least one pin body 46 that synchronizes the rotational component of the oscillating member 16 with the first lateral member 22. "Synchronizing the rotational component of the oscillating member 16 with the first lateral member 22" means maintaining the rotational component of the oscillating member 16 and the rotational component of the first lateral member 22 at the same magnitude within a numerical range including zero. The function of this pin body 46 is called the synchronization function.

[0032] For example, in this embodiment, the oscillating motion of the oscillating member 16 is converted into rotational motion of the oscillating member 16 by the gear mechanism 30. In this case, the rotational component of the internal gear 20, which is integrated with the casing 26, is kept at zero because the casing 26 is fixed to the external member. In this case, the rotational component of the oscillating member 16 is transmitted to the first lateral member 22 via the pin body 46, and the first lateral member 22 rotates with a rotational component of the same magnitude as the oscillating member 16. As a result, the pin body 46 synchronizes the rotational component of the oscillating member 16 with the first lateral member 22. In this case, the first lateral member 22 (carrier) becomes the output member, and the rotational component of the oscillating member 16 is output from the first lateral member 22.

[0033] In contrast to this embodiment, we consider a case where the oscillating motion of the oscillating member 16 is converted into the rotational motion of the internal gear 20 by the gear mechanism 30. In this case, the rotational component of the first lateral member 22 (carrier) is kept at zero by being fixed to the external member. The rotation of the oscillating member 16 is constrained by the pin body 46 that contacts the first lateral member 22, so that the rotational component of the oscillating member 16 is also kept at zero, similar to the first lateral member 22. In other words, the pin body 46 synchronizes the rotational component of the oscillating member 16 with the first lateral member 22. In this case, the casing 26, which is integrated with the internal gear 20, rotates together with the internal gear 20, and the rotational component of the internal gear 20 is output from the casing 26, which acts as the output member.

[0034] The gear unit 10 in this embodiment includes a plurality of pin bodies 46 arranged at intervals (equal angular intervals in this embodiment) in the circumferential direction. Each pin body 46 includes at least one pin 48. The pins 48 extend along the axial direction. In this embodiment, the pins 48 also serve as rolling elements 40 of the eccentric bearing 28.

[0035] The pin body 46 performs the aforementioned synchronization function by making contact with the first recess 50 provided on the rocking member 16 and the second recess 52 provided on the first lateral member 22. Multiple first recesses 50 are provided on the rocking member 16, and multiple second recesses 52 are provided on the first lateral member 22. The first recesses 50 and the second recesses 52 are provided individually, corresponding to each of the multiple pin bodies 46. The pin body 46 is rotatably mounted inside the corresponding first recesses 50 and second recesses 52.

[0036] Refer to Figures 2 and 3. The multiple first recesses 50 are arranged at intervals (equal angular intervals in this embodiment) in the circumferential direction of the eccentric portion 12. In this embodiment, the first recesses 50 are formed by the aforementioned fitting grooves 42a provided on the outer ring 42 of the eccentric bearing 28. In this embodiment, the first recesses 50 are provided on the oscillating member 16 by providing the fitting grooves 42a on the outer ring 42 which also serves as the oscillating member 16. Alternatively, when providing the first recesses 50 on the oscillating member 16, the fitting grooves 42a may be provided on a dedicated outer ring 42 integrated with the oscillating member 16.

[0037] One of the first recess 50 and the second recess 52 becomes a fitting recess 54 into which the pin body 46 is fitted so as to be rotatable. In this embodiment, the first recess 50 becomes the fitting recess 54. The fitting recess 54 has an arc shape with a radius slightly larger than the radius of the pin body 46 (the radius of the pin 48 in this embodiment) at the portion fitted into the fitting recess 54, and also has a groove shape that extends in the axial direction. The fitting recess 54 maintains the circumferential position of at least the eccentric portion 12 of the pin body 46 relative to the fitting recess 54. When the first recess 50 becomes the fitting recess 54, when the rocking member 16 rocks, the pin body 46 comes into contact with the first recess 50 (fitting recess 54) of the rocking member 16, allowing the pin body 46 to rock together with the rocking member 16.

[0038] Refer to Figures 2 and 4. The circular centers of the shapes formed by the multiple first recesses 50 are located on a common virtual circle Ca, similar to the fitting groove 42a. The circular centers of the shapes formed by the multiple second recesses 52 are located on a common virtual circle Cb. Figure 4 shows these virtual circles Ca and Cb. The multiple second recesses 52 are arranged at intervals (equal angle intervals in this embodiment) in the circumferential direction. The multiple second recesses 52 in this embodiment are formed on the side surface of the first lateral member 22. In this embodiment, the second recesses 52 have a bottomed concave shape that is recessed on one side in the axial direction on the side surface of the first lateral member 22.

[0039] The other of the first recess 50 and the second recess 52 becomes a loose-fitting recess 58 that forms a gap 56 between itself and the pin body 46, allowing the rocking member 16 to swing. In this embodiment, the second recess 52 becomes the loose-fitting recess 58. The loose-fitting recess 58 has a circular or arc shape with a radius obtained by adding an eccentricity e to the radius of the pin body 46 (the radius of the first roller 62, described later in this embodiment) in the portion located inside the loose-fitting recess 58. In this embodiment, it has a circular shape that satisfies these dimensional conditions. By satisfying these conditions, the loose-fitting recess 58 can allow the rocking member 16 and the pin body 46 to swing together when the rocking member 16 and the pin body 46 attempt to swing.

[0040] The pin body 46 is fitted into the fitting recess 54 so as to be rotatable, and is positioned so as to be rotatable inside the fitting recess 54 and the loose fitting recess 58, respectively. The pin body 46 is positioned so as to be rotatable inside the first recess 50 and the second recess 52, respectively. In order to perform the aforementioned synchronization function, the pin body 46 contributes to the transmission of torque between the rocking member 16 and the first lateral member 22 by contacting the first recess 50 (fitting recess 54) of the rocking member 16 and the second recess 52 (loose fitting recess 58) of the first lateral member 22. At this time, while held in the fitting recess 54, the pin body 46 revolves around the center of the loose fitting recess 58, with its contact position with the loose fitting recess 58.

[0041] An example of the operation of the gear mechanism 10 described above will now be explained. When the crankshaft 14 rotates due to the output of the drive source, the oscillating member 16 oscillates together with the external gear group 18 due to the eccentric portion 12 of the crankshaft 14. When the oscillating member 16 oscillates, the meshing position between the external gear group 18 and the internal gear 20 changes in the circumferential direction. As a result, the oscillating motion of the oscillating member 16 is converted into the rotational motion of either the oscillating member 16 or the internal gear 20, and the rotational component is output from the output member. In this embodiment, the oscillating member 16 rotates, and the first lateral member 22 rotates in sync with the rotational component of the oscillating member 16 by the pin body 46, and the rotational component is output from the first lateral member 22, which is the output member. At this time, in this embodiment, the output rotation, which is reduced by a reduction ratio corresponding to the difference in the number of teeth between the external gear group 18 and the internal gear 20, is output from the output member in response to the input rotation input to the crankshaft 14. When the internal gear 20 rotates, the casing 26, which is integrated with the internal gear 20, rotates together with the internal gear 20, and the rotational component of the internal gear 20 is output from the casing 26, which acts as an output member.

[0042] The effects of the gear mechanism 10 described above will now be explained.

[0043] (A1) When incorporating the pin body 46 into the gear device 10, if the pin body 46 is formed integrally with the first lateral member 22 by machining using an end mill or the like, the manufacturing cost becomes very high. In this case, according to this embodiment, the pin body 46 is provided so as to be able to rotate inside the first recess 50 of the oscillating member 16 and the second recess 52 of the first lateral member 22, and these are separate from the pin body 46. Therefore, when incorporating the pin body 46 into the gear device 10, it is only necessary to form the pin body 46 separately from the first lateral member 22 and then form the recesses 50 and 52 in the first lateral member 22 and the oscillating member 16, respectively. For this reason, compared to the case where the pin body 46 is formed integrally with the first lateral member 22 by machining, the processing required for incorporating the pin body 46 can be simplified, which is advantageous in reducing manufacturing costs.

[0044] (A2) When obtaining a pin body 46 integrally formed with the first lateral member 22 by machining, the pin body 46 is subjected to a large bending force during machining. In order to withstand this bending force, it is necessary to increase the outer diameter of the pin body 46, and there are limits to how small the outer diameter of the pin body 46 can be made in order to reduce the outer diameter of the gear device 10. In addition, in this case, it is necessary to secure a space between the pin bodies 46 large enough to allow a machining tool such as an end mill to pass through, and there are limits to how many pin bodies 46 can be made in order to reduce the outer diameter of the gear device 10. In this respect, according to the present embodiment, the first lateral member 22 and the pin body 46 are separate parts. Therefore, as described above, the situation in which the pin body 46 is subjected to a large bending force during machining can be avoided, and there is no need to increase the outer diameter of the pin body 46 in order to withstand this bending force. Therefore, compared to the case where the pin body 46 is integrally formed with the first lateral member 22 by machining, this method is advantageous in reducing the outer diameter of the pin body 46 when reducing the outer diameter of the gear device 10. In addition, there is no need to secure space between the pin bodies 46 large enough to pass through a machining tool. This, combined with the advantage of reducing the outer diameter of the pin body 46, makes it advantageous in increasing the number of pin bodies 46 when reducing the outer diameter of the gear device 10, compared to the case where the pin body 46 is integrally formed with the first lateral member 22 by machining.

[0045] Furthermore, reducing the outer diameter of the pin body 46 is advantageous for increasing the diameter of elements located radially inward relative to the pin body 46. For example, it is advantageous for increasing the outer diameter of the eccentric bearing 28 and the inner diameter of the hollow portion 14b of the crankshaft 14. Increasing the outer diameter of the eccentric bearing 28 in this way is advantageous for increasing the lifespan of the eccentric bearing 28. In addition, increasing the inner diameter of the hollow portion 14b of the crankshaft 14 is advantageous for reducing the weight of the gear unit 10.

[0046] Thus, one objective of this embodiment is to make it advantageous to reduce the outer diameter and increase the number of pin bodies 46 in order to reduce the outer diameter of the gear device 10. In this way, the maximum outer diameter of the gear device 10 may be, for example, 150 mm or less. The maximum outer diameter here refers to the radius of the circumscribed circle with the largest diameter that circumscribes the gear device 10, and whose center is the central axis C10 of the gear device 10. According to this embodiment, even when the maximum outer diameter of the gear device 10 is small, it has the advantage of making it advantageous to reduce the outer diameter and increase the number of pin bodies 46 as described above.

[0047] The pin body 46 is equipped with a pin 48 that also serves as a rolling element 40. Therefore, compared to the case where the pin body 46 does not serve as a rolling element 40 and the pin body 46 is provided separately from the rolling element 40, the number of parts in the gear unit 10 can be reduced. Consequently, the configuration of the gear unit 10 can be simplified, which is advantageous for reducing the outer diameter of the gear unit 10. In addition, when the pin body 46 and the rolling element 40 are separate, the radial position of the rolling element 40 can be shifted to the location of the pin body 46. Therefore, compared to the case where the pin body 46 is provided separately from the rolling element 40, it is advantageous for increasing the outer diameter of the eccentric bearing 28, as well as increasing the inner diameter of the hollow portion 14b of the crankshaft 14.

[0048] Let R1 be the radius of the circumscribed circle that tangent to the eccentric portion 12 of the crankshaft 14, and let R2 be the radius of the circumscribed circle that tangent to the rolling elements of the first crankshaft bearing 34. The centers of these circumscribed circles are the rotational centerline C14 of the crankshaft 14. In this case, R1 > R2 may be set to be advantageous for increasing the outer diameter of the eccentric bearing 28.

[0049] Next, other features of the gear mechanism 10 will be described. Refer to Figure 2. The pin body 46 includes a contact portion 60 provided at one end 48a on the axial side of the pin 48. The contact portion 60 contacts the second recess 52 of the first lateral member 22. The contact portion 60 may be subjected to a surface treatment to improve its hardness. The contact portion 60 may also be composed of a first roller 62 rotatably supported on one end 48a of the pin 48, as in this embodiment. The pin body 46 will include the first roller 62 in addition to the pin 48. The first roller 62 is capable of rolling contact with the second recess 52 of the first lateral member 22 and sliding contact with one end 48a of the pin 48. The advantages of this will be explained.

[0050] Refer to Figures 5(A) and 5(B). When the eccentric portion 12 oscillates, it rotates in the rotational direction P1 around the rotational centerline C14 of the crankshaft 14. Consequently, the pin 48 of the pin body 46 rotates in the rotational direction P2 opposite to the rotational direction P1 due to friction with the outer circumferential surface of the eccentric portion 12. Also, when the center C48 of the pin body 46 oscillates together with the oscillating member 16, it rotates in the rotational direction P1 around the center C52 of the second recess 52.

[0051] In this case, if the first roller 62 is absent, the contact between the pin 48 and the second recess 52 will include both rolling contact and sliding contact. Furthermore, since the rotational direction P1 of the center C48 of the pin 48 around the center C52 of the second recess 52 and the rotational direction P2 of the pin 48 are opposite, the relative speed at the sliding portion between the pin 48 and the second recess 52, which involves sliding contact, becomes very large. In addition, the difference in radius between the outer diameter of the pin 48 and the inner diameter of the second recess 52 becomes large, and the relative radius of curvature of these becomes small, resulting in a smaller oil film thickness at the sliding portion between the pin 48 and the second recess 52, which involves sliding contact. Combined with these factors, when the pin 48 constitutes the contact portion 60, wear and seizure are more likely to occur at the sliding portion between the contact portion 60 and the second recess 52.

[0052] In contrast, when the first roller 62 is present, the contact between the first roller 62 and the second recess 52 becomes rolling contact. Therefore, when the first roller 62 constitutes the contact portion 60, wear and seizure at the sliding portion between the contact portion 60 and the second recess 52 are less likely to occur compared to when the pin 48 constitutes the contact portion 60. Also, in this case, the first roller 62 rotates in the same rotation direction P3 as the rotation direction P2 of the pin 48, accompanied by sliding contact with the pin 48. Therefore, the relative speed at the sliding portion between the pin 48 and the first roller 62, accompanied by sliding contact, is smaller than the relative speed at the sliding portion between the pin 48 and the second recess 52, accompanied by sliding contact, as in the case when the first roller 62 is absent. Furthermore, the difference in radius between the pin 48 and the first roller 62 becomes small enough to be about the size of the bearing clearance (not shown), and their relative radii of curvature become larger. Therefore, the oil film thickness at the sliding surface between the pin 48 and the first roller 62, where sliding contact occurs, is greater than the oil film thickness at the sliding surface between the pin 48 and the second recess 52, where sliding contact occurs, as would be the case if the first roller 62 were absent. These factors combined make wear and seizure between the pin 48 and the first roller 62 less likely to occur.

[0053] Refer to Figure 2. The pin 48 may bend due to torque received from contact with the oscillating member 16 and the first lateral member 22. An increase in the amount of bending of the pin 48 can cause malfunctions. As a countermeasure, the gear device 10 may be provided with a first bending restricting part 64 which is provided radially inward with respect to one end 48a of the pin 48 and restricts the bending of the pin 48 by contacting the pin body 46. In this embodiment, the first bending restricting part 64 restricts the bending of the pin 48 by contacting the first roller 62 of the pin body 46 from the radially inward side. The first bending restricting part 64 has a circular shape which is eccentric by the same amount and in the same direction as the eccentric part 12 with respect to the rotation center line C14 of the crankshaft 14. The outer diameter of the circular shape formed by the first bending restricting part 64 is set to a size which avoids contact between the pin body 46 and the first bending restricting part 64 when the amount of bending of the pin 48 is small, so as not to hinder the movement of the pin body 46. This is advantageous in avoiding malfunctions caused by increased deflection of pin 48.

[0054] The oscillating member 16 and the first lateral member 22 are normally subjected to torque, and therefore their entire surface is hardened through surface hardening treatment. In contrast, the second lateral member 24 is not normally subjected to torque, and therefore its entire surface is not hardened through surface hardening treatment. However, in this embodiment, the outer ring side rolling surface 36a of the second crankshaft bearing 36 is provided on the inner circumferential surface of the second lateral member 24. Therefore, if the outer ring side rolling surface 36a has low hardness, there is a concern that problems due to wear (for example, a shortened lifespan of the second crankshaft bearing 36) may occur. As a countermeasure, a high-hardness region (not shown) may be provided on the outer ring side rolling surface 36a of the second lateral member 24 by partial surface treatment. Examples of partial surface treatments include laser hardening and high-frequency induction hardening. The high-hardness region has a higher surface hardness than the low-hardness region surrounding the high-hardness region on the second lateral member 24. This makes it possible to ensure the hardness of the outer ring side rolling surface 36a without increasing the hardness of the entire second lateral member 24.

[0055] (Second Embodiment) Refer to Figure 6. The gear device 10 of the second embodiment will be described. In the following embodiments, the components described in the first embodiment that are not described below may be the same as those in the first embodiment. The gear device 10 of this embodiment differs from the first embodiment mainly in the configuration of the external gear group 18 and the internal gear 20.

[0056] In this embodiment, the external tooth group 18 is provided separately from the rocking member 16. Specifically, unlike the first embodiment, each of the multiple external tooth portions 18a constituting the external tooth group 18 is provided on the other end 48b on the axial side of the pin 48 (rolling element 40) of each of the multiple pin bodies 46, which are separate from the rocking member 16. The external tooth portions 18a may be subjected to a surface treatment to improve hardness. The external tooth portion 18a may be composed of a second roller 70 (described later) rotatably supported on the other end 48b of the pin 48, as in this embodiment. The pin body 46 will include the pin 48, the first roller 62, and the second roller 70. The external tooth group 18 can rock together with the rocking member 16 by providing external tooth portions 18a on the multiple pins 48 that rock together with the rocking member 16. Furthermore, the outer periphery of the oscillating member 16 that does not have the external tooth group 18 may have a circular shape with the center line C12 of the eccentric portion 12 as its center.

[0057] In this embodiment, the internal gear 20 is provided on the second lateral member 24, and the internal gear body 20a is also the second lateral member 24. In this embodiment, a third recess 72 is provided on the side surface of the second lateral member 24, where the other end 48b of the pin 48 is positioned on the inside. The third recess 72 is continuous in an annular shape in the circumferential direction and in this embodiment forms a groove. The third recess 72 has an inner circumferential portion 72a on which a plurality of internal teeth 20b of the internal gear 20 are provided. In this embodiment, the plurality of internal teeth 20b have a trochoidal tooth profile, and the plurality of external teeth 18a have an arcuate tooth profile. The inner circumferential portion 72a of the third recess 72 has a curved shape that forms the trochoidal tooth profile of each of the plurality of internal teeth 20b. The combination of tooth profiles of the external teeth 18a and internal teeth 20b is not particularly limited, and various other combinations of tooth profiles may be adopted.

[0058] Thus, each of the multiple external teeth 18a in this embodiment is provided at the other end 48b of each of the multiple pins 48. Therefore, it is not necessary to provide the external tooth group 18 and the multiple internal teeth 20b between the casing 26 and the oscillating member 16, and the axial dimension of the oscillating member 16 does not need to be increased in order to ensure strength for the meshing between the external tooth group 18 and the internal gear 20. As a result, the axial dimension of the oscillating member 16 can be reduced, which is advantageous for flattening the gear device 10. In addition, compared to the case in which the external tooth group 18 is provided on the oscillating member 16, the circumscribed circle diameter R16 (described later) of the oscillating member 16 can be reduced in outer diameter, which is advantageous for reducing the outer diameter of the gear device 10. Furthermore, even if the outer diameter of the gear device 10 is not reduced, the radial positions of the pin body 46, rollers 62, 70, crankshaft bearings 34, 36, etc. can be shifted radially outward. This is advantageous for increasing the inner diameter of the hollow portion 14b of the crankshaft 14, which in turn is advantageous for reducing the weight of the gear unit 10.

[0059] The circumscribed circle diameter R18 of the external gear group 18 may be smaller than the circumscribed circle diameter R16 of the oscillating member 16. Here, the circumscribed circle diameter R18 of the external gear group 18 refers to the radius of the circle that circumscribes the multiple pin bodies 46 constituting the external gear group 18, with the centerline C16 (see Figure 1) of the oscillating member 16, which oscillates together with the external gear group 18, as the center of the circle. This circumscribed circle diameter R18 is synonymous with the tip circle diameter of the external gear group 18. The circumscribed circle diameter R16 of the oscillating member 16 refers to the radius of the circle that circumscribes the oscillating member 16, with the centerline C16 of the oscillating member 16 as the center of the circle. When the external gear group 18 is provided on the outer circumference of the oscillating member 16, the circumscribed circle diameters of both the external gear group 18 and the oscillating member 16 will be the same. As in this embodiment, setting the circumscribed circle diameter R18 < circumscribed circle diameter R16 is advantageous for reducing the outer diameter of the gear unit 10 compared to cases where this condition is not met.

[0060] The second roller 70 can make rolling contact with the internal teeth 20b of the internal gear 20 and sliding contact with the other end 48b of the pin 48. When the pin 48 is in direct contact with the internal gear 20, the contact between the pin 48 and the internal gear 20 includes both rolling and sliding contact. In contrast, when the second roller 70 is present, the contact between the second roller 70 and the internal gear 20 is rolling contact. Therefore, when the second roller 70 is present, wear and seizure at the sliding portion between the pin body 46 and the internal gear 20 are less likely to occur compared to when the pin 48 is in direct contact with the internal gear 20. Also, in this case, similar to the effect obtained by the presence or absence of the first roller 62 described above, the relative speed at the sliding portion between the pin 48 and the second roller 70, which involves sliding contact, becomes smaller, and the oil film thickness between them increases. These factors combined make wear and seizure between the pin 48 and the second roller 70 less likely to occur.

[0061] The gear device 10 may also include a second deflection restricting portion 74 provided radially inward from the other end 48b of the pin 48, which restricts the deflection of the pin 48 by contacting the pin body 46. In this embodiment, the second deflection restricting portion 74 restricts the deflection of the pin 48 by contacting the second roller 70 of the pin body 46 from the radially inward side. The second deflection restricting portion 74 has a circular shape that is eccentric by the same amount and in the same direction as the eccentric portion 12 with respect to the rotational centerline (not shown) of the crankshaft 14. The outer diameter of the circular shape formed by the second deflection restricting portion 74 is set to a size that avoids contact between the pin body 46 and the second deflection restricting portion 74 when the amount of deflection of the pin 48 is small, so as not to hinder the movement of the pin body 46. This is advantageous in avoiding problems caused by an increase in the amount of deflection of the pin 48.

[0062] The third recess 72 may include an outer peripheral portion 72b that is radially opposite to the inner peripheral portion 72a. In this case, the outer peripheral portion 72b may be provided radially inward from the other end 48b of the pin 48, as in the second deflection restricting portion 74, and restrict the deflection of the pin 48 by contact with the pin body 46. This is advantageous in avoiding problems caused by an increase in the amount of deflection of the pin 48.

[0063] The gear device 10 described above has a configuration that provides at least the effects of (A1) and (A2) described above, and can achieve similar effects.

[0064] (Third Embodiment) Refer to Figure 7. The gear device 10 of the third embodiment will be described. The gear device 10 of the third embodiment differs from the first embodiment mainly in the configuration of the eccentric bearing 28 and the pin body 46.

[0065] In this embodiment, the pin body 46 is provided separately from the rolling elements 40 of the eccentric bearing 28. Unlike the first embodiment, the outer ring side rolling surface 42b of the eccentric bearing 28 is continuous in an annular shape in the circumferential direction of the eccentric portion 12. In this embodiment, the pin body 46 is composed only of pins 48. In this embodiment, the axial dimension L48 of the pin 48 is smaller than the diameter R48.

[0066] The first recess 50 of the rocking member 16 is provided on the side surface 16b of the rocking member 16. The second recess 52 of the first lateral member 22 is provided on the side surface 22a of the first lateral member 22 that faces the side surface 16b of the rocking member 16 in the axial direction. The first recess 50 and the second recess 52 are provided at positions that face each other in the axial direction of the rocking member 16 and the first lateral member 22, respectively.

[0067] In this embodiment, the first recess 50 is a bottomed recess in the side surface 16b of the rocking member 16, recessed on the other axial side (right side in the plane of Figure 7). The pin body 46 placed in such a bottomed recess first recess 50 will not penetrate the rocking member 16 in the axial direction. In this embodiment, the second recess 52 is a bottomed recess in the side surface 22a of the first lateral member 22, recessed on one axial side (left side in the plane of Figure 7). The pin body 46 placed in such a bottomed recess second recess 52 will not penetrate the first lateral member 22 in the axial direction.

[0068] Refer to Figures 7 and 8. In this embodiment, the first recess 50 becomes the fitting recess 54, and the second recess 52 becomes the loose fitting recess 58. The fitting recess 54 in this embodiment is circular in shape with a radius slightly larger than the radius of the pin body 46 (here, the radius of the pin 48) at the portion that fits into the fitting recess 54. The loose fitting recess 58 applied to this embodiment is circular or arc-shaped in shape with a radius obtained by adding an eccentricity e to the radius of the pin body 46 (here, the radius of the pin 48) at the portion that is located inside the loose fitting recess 58. The loose fitting recess 58 in this embodiment is circular in shape that satisfies this condition.

[0069] In addition, the first recess 50 may become a loose-fitting recess 58, and the second recess 52 may become a fitted recess 54. In this case, when the rocking member 16 rocks, the pin body 46 held in the fitted recess 54 of the first lateral member 22 will not rock with the rocking member 16. In this case, the loose-fitting recess 58 of the rocking member 16 only needs to be circular in shape, with a radius obtained by adding an eccentricity e to the radius of the pin body 46 in the portion positioned inside the loose-fitting recess 58. This allows the loose-fitting recess 58 to contact the pin body 46 held in the fitted recess 54 while allowing the rocking member 16 to rock.

[0070] The pin body 46 receives a force F1 through contact with the first recess 50 of the oscillating member 16, and at the same time receives a force F2 through contact with the second recess 52 of the first lateral member 22. These forces F1 and F2 act on the pin body 46 as shear forces acting in opposite directions on a virtual plane perpendicular to the axial direction.

[0071] If the pin body 46 penetrates the oscillating member 16 in the axial direction, the axial range in which the pin body 46 receives force F1 from the oscillating member 16 becomes wider. Consequently, the pin body 46 becomes more susceptible to bending moments, and the dominant failure mode of the pin body 46 is more likely to be a bending mode in which it fails under the influence of that bending moment. In contrast, the pin body 46 in this embodiment does not penetrate the first lateral member 22. Therefore, compared to the case in which the pin body 46 penetrates the oscillating member 16 in the axial direction, the axial range in which the pin body 46 receives force F1 from the oscillating member 16 can be narrowed. As a result, the pin body 46 becomes less susceptible to bending moments, and the dominant failure mode of the pin body 46 is more likely to be a shear mode. Generally, it is easier to ensure strength against shear mode than against bending mode. By creating a structure that is more likely to result in a shear mode, which is easier to ensure strength, it is advantageous in ensuring the lifespan of the pin body 46.

[0072] To make the dominant failure mode of the pin body 46 a shear mode, it is desirable to narrow the axial range in which the pin body 46 receives a force F1 from the oscillating member 16, while also narrowing the axial range in which the pin body 46 receives a force F2 from the first lateral member 22. From this viewpoint, it is desirable to make the axial dimension L48 of the pin 48 smaller than the diameter R48. This narrows the axial range in which the pin body 46 receives forces F1 and F2 from the oscillating member 16 and the first lateral member 22, compared to the case in which the axial dimension L48 of the pin 48 is greater than or equal to the diameter R48. In turn, this is advantageous in making the dominant failure mode of the pin body 46 a shear mode and is advantageous in ensuring the lifespan of the pin body 46.

[0073] In order to narrow the axial range in which the pin body 46 receives a force F1 from the rocking member 16, it is desirable to make the axial dimension L50 of the first recess 50 in which the pin body 46 is positioned as short as possible. From this viewpoint, this axial dimension L50 may be, for example, 0.5 times or less the maximum axial dimension L16 of the rocking member 16. Also, in order to narrow the axial range in which the pin body 46 receives a force F2 from the first lateral member 22, it is desirable to make the axial dimension L52 of the second recess 52 in which the pin body 46 is positioned as short as possible. From this viewpoint, this axial dimension L52 may be, for example, 0.5 times or less the axial dimension L16 of the rocking member 16.

[0074] The gear device 10 described above has a configuration that allows for obtaining the effects of (A1) and (A2) described above, and similar effects can be obtained. Furthermore, in order to exert the synchronization function of the pin body 46, it is only necessary to provide the first recess 50 and the second recess 52 at positions that are opposite each other in the axial direction, respectively, for the oscillating member 16 and the first lateral member 22. Therefore, the structure of the oscillating member 16 and the first lateral member 22 can be simplified, which is advantageous for cost reduction.

[0075] (Fourth Embodiment) Refer to Figure 9. The gear device 10 of the fourth embodiment will be described. The gear device 10 of the fourth embodiment differs from the gear device 10 of the first embodiment mainly in the configuration of the oscillating member 16 and the pin body 46. The pin body 46 of the gear device 10 of this embodiment is also provided separately from the rolling elements 40 of the eccentric bearing 28, similar to the third embodiment.

[0076] The oscillating member 16 in this embodiment comprises a large outer diameter portion 16c and a small outer diameter portion 16d provided on one axial side (left side of the paper in Figure 9) relative to the large outer diameter portion 16c. The outer diameter of the small outer diameter portion 16d is smaller than the outer diameter of the large outer diameter portion 16c. Here, the outer diameter of the oscillating member 16 refers to the radius of the oscillating member 16 in a direction perpendicular to the center line C16 of the oscillating member 16 (not shown in Figure 9, see Figure 1). In this embodiment, an external tooth group 18 is provided on the outer circumference of the large outer diameter portion 16c.

[0077] The first lateral member 22 is provided with a crankshaft hole 22b in which the crankshaft 14 is positioned on the inside. The first lateral member 22 is provided with a small inner diameter portion 22c on one axial side with respect to the rocking member 16, and a large inner diameter portion 22d on the other axial side (right side of the paper in Figure 9) with respect to the small inner diameter portion 22c. The small inner diameter portion 22c and the large inner diameter portion 22d of the first lateral member 22 each form the crankshaft hole 22b. The inner diameter of the large inner diameter portion 22d is larger than the inner diameter of the small inner diameter portion 22c. The inner diameter of the crankshaft hole 22b here refers to the radius of the crankshaft hole 22b in a direction perpendicular to the rotation centerline C14 of the crankshaft 14. In this embodiment, a first crankshaft bearing 34 is positioned between the small inner diameter portion 22c of the first lateral member 22 and the crankshaft 14.

[0078] Refer to Figures 9 and 10. The large inner diameter portion 22d of the first lateral member 22 is provided at a position radially opposite to the small outer diameter portion 16d of the oscillating member 16. The first recess 50 of the oscillating member 16 is groove-shaped in a cross section perpendicular to the axial direction, and is provided on the outer circumference of the small outer diameter portion 16d of the oscillating member 16. The groove of the first recess 50 extends in the axial direction and opens radially outward. The second recess 52 of the first lateral member 22 is groove-shaped in a cross section perpendicular to the axial direction, and is provided on the inner circumference of the large inner diameter portion 22d of the first lateral member 22. The groove of the second recess 52 extends in the axial direction and opens radially inward.

[0079] In this embodiment, the first recess 50 becomes a fitting recess 54, and the second recess 52 becomes a loose fitting recess 58. The fitting recess 54 in this embodiment has an arc shape with a radius slightly larger than the radius of the pin body 46 (the radius of the pin 48 in this embodiment) at the portion that fits into the fitting recess 54. The loose fitting recess 58 in this embodiment has an arc shape with a radius obtained by adding an eccentricity e to the radius of the pin body 46 (the radius of the pin 48 in this embodiment) at the portion that is positioned inside the loose fitting recess 58.

[0080] The gear device 10 described above has a configuration that allows for obtaining the effects of (A1) and (A2) described above, and similar effects can be obtained. In addition, the second recess 52 is groove-shaped and provided on the inner circumference of the first lateral member 22. Therefore, compared to the case in which the second recess 52 is a closed cross-sectional hole in a cross-section perpendicular to the axial direction, it is advantageous to reduce the radial dimension of the first lateral member 22 at a position that overlaps radially with the pin body 46.

[0081] In this embodiment, the oscillating member 16 and the first lateral member 22 have portions that overlap radially. In contrast, in the first to third embodiments, it is not necessary to provide such radially overlapping portions on the oscillating member 16 and the first lateral member 22. Therefore, these first to third embodiments are advantageous for flattening the gear device 10.

[0082] Other features of the gear apparatus 10 described above will now be explained. As the oscillating member 16 and the pin body 46 oscillate, a gap 80 is created between the fitting recess 54 and the loose fitting recess 58, allowing the pin 48 to fall radially out of the fitting recess 54. When the first recess 50 of the oscillating member 16 becomes the fitting recess 54, a gap 80 is created that allows the pin 48 to fall radially outward.

[0083] As a countermeasure, of the rocking member 16 and the first lateral member 22, the rocking member 16, in which the fitting recess 54 is formed, may be provided with a fall-prevention hole 82 that prevents the pin body 46 from falling radially out of the fitting recess 54. In this embodiment, the fall-prevention hole 82 is formed on the side surface of the large outer diameter portion 16c of the rocking member 16 and has a closed cross-sectional shape in a cross section perpendicular to the axial direction. A part of the pin body 46 (in this case, the other end of the pin 48) is fitted into the fall-prevention hole 82 so as to be able to rotate. The fall-prevention hole 82 may be circular in shape, for example, with a diameter slightly larger than the diameter of the pin body 46 at the portion fitted into the fall-prevention hole 82. By being fitted into the fall-prevention hole 82, the pin body 46 is prevented from falling radially out of the fitting recess 54.

[0084] Alternatively, the first recess 50 of the oscillating member 16 may become a loose-fitting recess 58, and the second recess 52 of the first lateral member 22 may become a fitted recess 54. In this case, as the oscillating member 16 oscillates, a gap is created between the fitted recess 54 and the loose-fitting recess 58 that allows the pin 48 to fall radially inward into the fitted recess 54 of the first lateral member 22. In this case, the detachment prevention hole 82 only needs to be provided in the first lateral member 22, of the oscillating member 16, where the fitted recess 54 is formed. In this case, the detachment prevention hole 82 only needs to be formed on the side surface of the large inner diameter portion 22d of the first lateral member 22. In other words, the detachment prevention hole 82 only needs to be provided in the member of the oscillating member 16 and the first lateral member 22 where the fitted recess 54 is formed.

[0085] Next, features that may be applied to all embodiments will be described. Refer to the third embodiment in Figure 7. A lubricant reservoir 84 may be formed in at least one of the first recess 50 and the second recess 52. In this embodiment, it is formed in the second recess 52. The lubricant reservoir 84 is provided as a recess that opens into the inner surface of the recess in which the lubricant reservoir 84 is formed and is recessed relative to that inner surface. In this embodiment, the lubricant reservoir 84 opens into the bottom surface of the recess. A lubricant such as lubricating oil or grease is stored in the lubricant reservoir 84.

[0086] The pin body 46 is provided so as to be rotatable with respect to the first recess 50 of the oscillating member 16 and the second recess 52 of the first lateral member 22. Therefore, there is a problem that the pin body 46 is prone to wear due to sliding with the first recess 50 and the second recess 52. In this embodiment, a lubricant reservoir 84 is formed in at least one of the first recess 50 and the second recess 52 that are close to the pin body 46. Therefore, by lubricating the pin body 46 with the lubricant stored in the lubricant reservoir 84, wear of the pin body 46 due to sliding with the first recess 50 and the second recess 52 can be effectively suppressed. In order to obtain this effect, the lubricant reservoir 84 may be formed in the first recess 50 in addition to the second recess 52, or it may be formed in both the first recess 50 and the second recess 52. The above lubricant reservoir 84 may also be applied to gear devices 10 of other embodiments other than the third embodiment.

[0087] Refer to the first embodiment in Figure 2. The pin body 46 is provided so as to be rotatable with respect to the first recess 50 of the oscillating member 16 and the second recess 52 of the first lateral member 22, respectively. Therefore, as in the first embodiment, when the first recess 50 and the second recess 52 are provided in positions offset in the axial direction, if the length of the pin body 46 increases, the force received by the pin body 46 from the second recess 52 of the first lateral member 22 may cause the pin body 46 to tilt, which may cause the oscillating member 16 to tilt. Here, tilting of the oscillating member 16 means that the center line C16 of the oscillating member 16 moves at an angle with respect to the axial direction.

[0088] Refer to the third embodiment in Figure 7. The oscillating member 16 is subjected to a meshing reaction force due to the meshing between the external tooth group 18 provided on the outer circumference of the oscillating member 16 and the internal gear 20. In addition, the oscillating member 16 is also subjected to a force due to the contact between the second recess 52 of the first lateral member 22 and the pin body 46. In the oscillating member 16 of the third embodiment, the axial range in which the meshing reaction force acts on the oscillating member 16 and the axial range in which a force acts on the oscillating member 16 due to contact with the pin body 46 are different, resulting in an imbalance in the forces acting on the oscillating member 16. The same is true for the oscillating member 16 of the fourth embodiment in Figure 9. This imbalance in forces may cause the oscillating member 16 to tilt.

[0089] As described above, the oscillating member 16 in the first, third, and fourth embodiments may tilt. Tilting of the oscillating member 16 can cause problems such as uneven wear of the external gear group 18 that oscillates with the oscillating member 16, so improvement is desirable. Refer to Figure 2. As a countermeasure, the gear device 10 may be equipped with a thrust bearing 86 positioned between the second lateral member 24 and the oscillating member 16. The thrust bearing 86 can receive the thrust load transmitted from the oscillating member 16 when it attempts to tilt. By receiving the thrust load from the oscillating member 16, the thrust bearing 86 can limit the tilting of the oscillating member 16 and suppress problems caused by that tilting.

[0090] The thrust bearing 86 in this embodiment is a rolling bearing, but it may also be a sliding bearing. The rolling thrust bearing 86 comprises a plurality of rolling elements 86a that contact the oscillating member 16. The rolling elements 86a in this embodiment are spheres, but they may be various types of rolling elements such as rollers. The plurality of rolling elements 86a are arranged in an annular shape around the central axis C10 of the gear device 10. The rolling elements 86a in this embodiment are held rotatably on the second lateral member 24. In addition, the thrust bearing 86 may also include a cage fixed to the oscillating member 16 that holds the plurality of rolling elements 86a.

[0091] During operation of the gear unit 10, the oscillating member 16 oscillates, and the oscillating member 16 and the second lateral member 24 rotate relative to each other around the central axis C10 of the gear unit 10. The rolling element 86a is capable of rolling at least in the tangential direction of a circle centered on the central axis C10. Therefore, by the oscillating member 16 rolling into contact with the rolling element 86a in the aforementioned tangential direction, the frictional resistance between the oscillating member 16 and the rolling element 86a caused by the relative rotation of the oscillating member 16 and the second lateral member 24 can be reduced. In this embodiment, the rolling element 86a is a sphere capable of rolling in all directions on an orthogonal plane perpendicular to the central axis C10 of the gear unit 10. Therefore, by ensuring that the rolling elements 86a make rolling contact with each other in all directions on a plane perpendicular to the rolling elements 86a, the frictional resistance between the oscillating member 16 and the rolling elements 86a caused by the oscillating of the oscillating member 16 and the relative rotation between the oscillating member 16 and the second lateral member 24 can be reduced.

[0092] Furthermore, in order to limit the tilting of the rocking member 16 using the thrust bearing 86, an axial preload may be applied to the rocking member 16 by increasing the axial dimension of the member positioned between the first lateral member 22 and the rocking member 16. The member positioned between the first lateral member 22 and the rocking member 16 here refers to, for example, the first roller 62 in Figure 2 or the pin body 46 in Figure 7.

[0093] (Fifth Embodiment) Refer to Figure 11. The gear device 10 of the fifth embodiment will be described. The gear device 10 of the fifth embodiment differs from the second embodiment mainly in the configuration of the third and fourth deflection restricting parts 90 and 92.

[0094] As a countermeasure against the deflection of the pin 48 mentioned above, the oscillating member 16 may be provided with a third deflection restricting portion 90 that is provided radially outward from the first roller 62 of the pin body 46 and restricts the deflection of the pin 48 by contact with the first roller 62. The third deflection restricting portion 90 is provided on the side surface 16b on one axial side of the oscillating member 16 and has a bottomed concave shape that is recessed on the other axial side. The first roller 62 is fitted into the third deflection restricting portion 90 so as to be able to rotate. The third deflection restricting portion 90 has an arc shape with a radius slightly larger than the radius of the first roller 62. The inner diameter of the third deflection restricting portion 90 is set to a size that avoids contact between the first roller 62 and the third deflection restricting portion 90 when the amount of deflection of the pin 48 is small, so as not to hinder the movement of the first roller 62. The third deflection restricting section 90 can contact the first roller 62 from both the radially outward and circumferential sides, thereby restricting the deflection of the pin 48. This is advantageous in avoiding problems caused by an increase in the amount of deflection of the pin 48. In particular, the presence of the first deflection restricting section 64, which restricts the deflection of the pin 48 by contacting the first roller 62 from the radially inward side, is especially advantageous in restricting the deflection of the pin 48.

[0095] Furthermore, as a countermeasure against the deflection of the pin 48, the oscillating member 16 may be provided with a fourth deflection restricting portion 92 that is provided radially outward from the second roller 70 of the pin body 46 and restricts the deflection of the pin 48 by contacting the second roller 70. The fourth deflection restricting portion 92 is provided on the side surface of the oscillating member 16 on the other axial side and has a bottomed concave shape that is recessed on one axial side. The second roller 70 is fitted into the fourth deflection restricting portion 92 so as to be rotatable. The fourth deflection restricting portion 92 has an arc shape with a radius slightly larger than the radius of the second roller 70. The inner diameter of the fourth deflection restricting portion 92 is set to a size that avoids contact between the second roller 70 and the fourth deflection restricting portion 92 when the amount of deflection of the pin 48 is small, so as not to hinder the movement of the second roller 70. The fourth deflection restricting portion 92 can contact the second roller 70 from both the radially outward and circumferential sides, thereby restricting the deflection of the pin 48. This is advantageous in avoiding problems caused by increased deflection of the pin 48. In particular, the presence of a second deflection restricting section 74 that restricts the deflection of the pin 48 by contacting the second roller 70 from the radially inward side is especially advantageous in restricting the deflection of the pin 48.

[0096] The gear apparatus 10 described above can achieve the same effects as the gear apparatus 10 of the second embodiment, except for the third and fourth deflection restricting sections 90 and 92.

[0097] Next, we will explain the transformation forms of each component described so far.

[0098] As a specific type of eccentric oscillating gear device, a center-crank type was described in which the crankshaft 14 is positioned on the central axis C10 of the gear device 10. This type is not particularly limited, and for example, a distribution type in which multiple crankshafts 14 are positioned radially offset from the central axis C10 may also be used. The number of eccentric portions 12 of the crankshaft 14 is not particularly limited and may be multiple.

[0099] An example has been described in which the gear device 10 functions as a reduction gear that reduces the rotation of an input member and outputs it from an output member. In this case, the casing 26 may be the output member instead of the first lateral member 22. In addition, the gear device 10 may also function as a speed increaser. In this case, the casing 26 or the first lateral member 22 may be the input member instead of the crankshaft 14, and the crankshaft 14 may be the output member. In this case, the gear mechanism 30 only needs to convert the rotational motion of the internal gear 20 or the oscillating member 16 into the oscillating motion of the oscillating member 16 when the internal gear 20 or the oscillating member 16 rotates due to the rotation of the casing 26 or the first lateral member 22. The rotation of the internal gear 20 here means that the internal gear 20, which is integrated with the casing 26, rotates due to the rotation of the casing 26. Furthermore, the rotation of the oscillating member 16 means that when the first lateral member 22 rotates, the oscillating member 16 rotates in synchronization with the rotation (rotational component) of the first lateral member 22 due to the pin body 46.

[0100] When the contact portion 60 of the pin body 46, as shown in Figure 1, is provided at one end 48a of each of the multiple pins 48, the contact portion 60 of the pin body 46 may be formed by the one end 48a of each of the multiple pins 48 themselves.

[0101] When each of the multiple external tooth portions 18a constituting the external tooth group 18 as shown in Figure 6 is provided on the other end 48b of each of the multiple pins 48 (rolling elements 40), each of the multiple external tooth portions 18a may be composed of the other end 48b of each of the multiple pins 48 themselves.

[0102] Figure 6 illustrates an example where one axial side of the rocking member 16 is on the left side of the paper, and the other axial side is on the right side of the paper. In this example, the first lateral member 22 on one axial side of the rocking member 16 is a carrier positioned inside the casing 26, and the second lateral member 24 on the other axial side is a casing connecting member connected to the casing 26. Alternatively, one axial side of the rocking member 16 may be on the right side of the paper, and the other axial side may be on the left side of the paper. In this case, the first lateral member 22 may be a casing connecting member, and the second lateral member 24 may be a carrier. In this case, the first lateral member 22 (casing connecting member) may have a second recess 52, which may be either a fitting recess 54 or a loose fitting recess 58, and the second lateral member 24 (carrier) may have a third recess 72, which may have multiple internal teeth 20b. In this case, the configurations of both axial ends of the pin body 46 can also be swapped in the axial direction. Specifically, a contact portion 60 that contacts the second recess 52 can be provided at one end 48a (right end in the paper) of the pin 48 of the pin body 46, and an external tooth portion 18a can be provided at the other end 48b (left end in the paper) of the pin 48. In this case, the gear mechanism 30 is composed of the external tooth portions 18a provided at the other end 48b (left end in the paper) of each of the multiple pins 48 and the multiple internal tooth portions 20b provided in the third recess 72 of the second lateral member 24. In this case as well, either the casing 26 or the carrier may be the output member.

[0103] Even when the pin body 46 and the rolling element 40 are separate entities, as in the third and fourth embodiments, the rolling element 40 may be made pivotable together with the rocking member 16, as shown in Figure 6, and an external tooth portion 18a may be provided at the other end of the rolling element 40 on the axial side.

[0104] The pin body 46 may be configured so that it does not axially penetrate the oscillating member 16 as shown in Figure 7, while the axial dimension L48 of the pin 48 may be greater than or equal to the diameter R48.

[0105] The contents of each component described in the embodiments above are illustrative. The abstract technical ideas derived from these should not be interpreted restrictively to the contents of this specification. Many design changes, such as modifications, additions, and deletions, are possible for the contents of each component described in the embodiments. Such modifications are emphasized by the notation "this form" and "embodiment." However, design changes are also permitted for contents without such notation. The geometric conditions and terms used in this specification to specify shapes include not only the strict meaning of the term but also a range to which similar functions can be expected. The structures and numerical values ​​mentioned in embodiments and variations naturally include those that can be considered identical when considering manufacturing tolerances, etc. Any combination of the above components is also valid. For example, any explanatory items from other embodiments may be combined with an embodiment, and any explanatory items from an embodiment and other variations may be combined with a variation. The hatching applied to the cross-sections in the drawings does not limit the material of the object to which the hatching is applied. Components composed of a single member in the description in this specification may be composed of multiple members. Similarly, components composed of multiple members may be composed of a single member. [Explanation of Symbols]

[0106] 10...Gear unit, 12...Eccentric part, 14...Crankshaft, 16...Oscillating member, 18...External gear group, 18a...External teeth, 20...Internal gear, 22...First lateral member, 24...Second lateral member, 28...Eccentric bearing, 40...Rolling element, 42...Outer ring, 42a...Matching groove, 46...Pin body, 48...Pin, 50...First recess, 52...Second recess, 54...Matching recess, 58...Loose fitting recess, 60...Contact part, 82...Loosening prevention hole, 86...Thrust bearing.

Claims

1. A crankshaft having an eccentric portion, The rocking member is oscillated by the eccentric portion, The external teeth group that swings together with the aforementioned swinging member, An internal gear that meshes with the aforementioned external gear group, A first lateral member is positioned on one side in the axial direction relative to the rocking member, The device comprises a pin body that makes contact with a first recess provided in the rocking member and a second recess provided in the first lateral member, and synchronizes the rotational component of the rocking member with the first lateral member, The pin body is an eccentric oscillating gear device that is rotatably mounted inside the first recess and the second recess, respectively.

2. The system includes an eccentric bearing positioned between the rocking member and the eccentric portion, The eccentric bearing comprises a plurality of rolling elements that can swing together with the rocking member, The eccentric oscillating gear device according to claim 1, wherein the pin body comprises a pin that also serves as the rolling element.

3. Multiple fitting grooves are formed on the inner circumferential surface of the outer ring of the eccentric bearing, into which the pin is fitted so as to rotate freely. The eccentric oscillating gear device according to claim 2, wherein each of the plurality of fitting grooves constitutes the first recess.

4. The eccentric oscillating gear device according to claim 2, wherein the pin body is provided at one end on the axial side of the pin and has a contact portion that contacts the second recess.

5. The eccentric oscillating gear device according to claim 4, wherein the contact portion is comprised of a roller rotatably supported on one end of the pin.

6. The eccentric oscillating gear device according to claim 1, wherein the first recess and the second recess are provided at positions opposite to each other in the axial direction of the oscillating member and the first lateral member, respectively.

7. The eccentric oscillating gear device according to claim 6, wherein the pin body does not penetrate the oscillating member in the axial direction.

8. The aforementioned pin body comprises pins, The eccentric oscillating gear device according to claim 6, wherein the axial dimension of the pin is smaller than its diameter.

9. The eccentric oscillating gear device according to claim 1, wherein the second recess is groove-shaped and provided on the inner circumference of the first lateral member.

10. The eccentric oscillating gear device according to claim 9, wherein the first recess is groove-shaped and provided on the outer circumference of the oscillating member.

11. One of the first recess and the second recess becomes a fitting recess into which the pin body is fitted so as to be able to rotate. The other of the first recess and the second recess is a loose fitting recess that forms a gap between itself and the pin body that allows the swinging member to swing. The eccentric oscillating gear device according to claim 10, wherein the oscillating member and the first lateral member on which the fitting recess is formed are provided with a detachment prevention hole that prevents the pin body from falling radially out of the fitting recess.

12. The system includes an eccentric bearing positioned between the rocking member and the eccentric portion, The eccentric bearing comprises a plurality of rolling elements that can swing together with the rocking member, The internal gear is positioned on the opposite side axially from the rocking member. The eccentric oscillating gear device according to claim 1, wherein each of the multiple external teeth constituting the external tooth group is provided at the other end on the axial side of each of the multiple rolling elements.

13. The eccentric oscillating gear device according to claim 12, wherein the external teeth portion is composed of rollers rotatably supported on the other end of the rolling element.

14. The eccentric oscillating gear device according to claim 12, wherein the circumscribed circle diameter of the external gear group is smaller than the circumscribed circle diameter of the oscillating member.

15. A second lateral member is positioned on the axial side opposite to the aforementioned rocking member, The eccentric oscillating gear device according to claim 1, further comprising a thrust bearing disposed between the second lateral member and the oscillating member.

16. One of the first recess and the second recess becomes a fitting recess into which the pin body is fitted so as to be able to rotate. The eccentric oscillating gear device according to claim 1, wherein the other of the first recess and the second recess is a loose fitting recess that forms a play between itself and the pin body that allows the oscillating member to swing.

17. The eccentric oscillating gear device according to claim 1, wherein a lubricant reservoir is formed in at least one of the first recess and the second recess.

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