Eccentrically Oscillating Gear Device

Abstract

An eccentrically oscillating gear device (10) is provided which is advantageous in that it suppresses the tipping of a roller during the operation of arranging rollers (50). An eccentrically oscillating gear device (10) comprises a crankshaft (14) containing eccentric sections (12), oscillating gears (16) capable of oscillating using the eccentric sections (12), and eccentric bearings (20), each of which is arranged between the eccentric section (12) and the oscillating gear (16).The eccentric bearings (20) contain roller groups (52) consisting of several rollers (50) and do not include a cage for holding relative positions of the several rollers (50). The crankshaft (14) contains receiving sections (60) capable of limiting axial movement of the corresponding roller groups (52). The receiving section (60) corresponds to the eccentric section (12) located at a position that overlaps with the roller group (52) corresponding to the receiving section (60) in a radial direction of the crankshaft (14). An outer radius dimension (L60) between a central axis (L12) of the eccentric section (12) corresponding to the receiving section (60) and an outer circumferential end of the receiving section (60) is larger than a circumscribed circular radius (R52) of the roller group (52) corresponding to the receiving section (60) in a maximum eccentric direction (Da) of the crankshaft (14). eccentric section (12).

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present disclosure relates to an eccentrically oscillating gear device.

[0002] This application claims priority from Japanese patent application No. 2024-195973, filed on November 8, 2024, which is incorporated herein in its entirety by reference. Description of the state of the art

[0003] Japanese unexamined patent publication No. 2018-119649 discloses an eccentrically oscillating gear device comprising a crankshaft containing eccentric sections, oscillating gears capable of oscillating using the eccentric sections, and eccentric bearings, each positioned between the eccentric section and the oscillating gear. The crankshaft includes receiving sections capable of limiting axial movement of the eccentric bearings. In the gear device disclosed in Japanese unexamined patent publication No. 2018-119649, an outer radius dimension (to be described later) between a central axis of the eccentric section and an outer circumferential end of the receiving section is set such that it is smaller than a circumscribed circular radius of several rolling elements used for the eccentric bearing in a maximum eccentric direction of the eccentric section. SUMMARY OF THE INVENTION

[0004] A bearing containing multiple rollers and lacking a cage to maintain the relative positions of those rollers can be used as an eccentric bearing. In this case, individual positioning of the multiple rollers between the eccentric section of the crankshaft and the oscillating gear is required during assembly of the gear assembly.

[0005] The present inventor has recognized a problem in that the roller is likely to tip over during the process of arranging the rollers in the structure disclosed in Japanese unexamined patent publication No. 2018-119649. In the event that a roller tips over during this process, the time and effort required to retrieve the tipped-over roller and re-arrange it will be necessary, resulting in an increase in working hours.

[0006] Therefore, one objective of the present disclosure is to provide an eccentrically oscillating gear device which is advantageous in that it suppresses the tipping of a roller during the operation of arranging rollers.

[0007] An eccentrically oscillating gear device according to one aspect of the present disclosure comprises a crankshaft containing eccentric sections, oscillating gears capable of oscillating using the eccentric sections, and eccentric bearings, each of which is arranged between the eccentric section and the oscillating gear.The eccentric bearings contain roller assemblies consisting of multiple rollers and do not include a cage for holding relative positions of the multiple rollers. The crankshaft contains receiving sections capable of limiting axial movement of the corresponding roller assemblies. The receiving section corresponds to the eccentric section, which is located at a position that overlaps with the roller assembly corresponding to the receiving section in a radial direction of the crankshaft. An outer radius dimension between a central axis of the eccentric section corresponding to the receiving section and an outer circumferential end of the receiving section is greater than a circumscribed circular radius of the roller assembly corresponding to the receiving section in a maximum eccentric direction of the eccentric section.

[0008] According to the eccentrically oscillating gear device of the aspect of the present disclosure, it is advantageous to suppress tipping of a roller during work of arranging rollers. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a side cross-sectional view of a gear device according to one embodiment. Fig. 2 is an enlarged view of the in Fig. 1 shown gear device. Fig. 3A is a cross-sectional view showing part of a cross-section along line AA from Fig. 2 and shows a first reception section, and Fig. 3B is a cross-sectional view showing part of a cross-section along line BB from Fig. 2 and shows a second reception section. Fig. Figure 4 is a diagram showing the operation of arranging a roller using the gear device according to the embodiment. Fig. Figure 5A is a side cross-sectional view showing a major part of a gear device according to a reference embodiment, and Fig. 5B is a cross-sectional view showing part of a cross-section along line CC of Fig. 5A and shows a first reception section. Fig. Figure 6A is a diagram showing the inclination of a roller in a case where the gear device is used according to the reference embodiment, and Fig. 6B is a diagram showing the tipping of the roller in a case where an eccentric section and a bearing hole are in one direction of an arrow V. Fig. 6A is considered, it shows. DETAILED DESCRIPTION OF THE INVENTION

[0009] An eccentrically oscillating gear device according to an embodiment of the present disclosure is described below. The same or equivalent components are designated by the same reference numerals, and their repeated description is omitted. In each drawing, components are omitted, enlarged, or reduced as necessary for the sake of simplicity. The drawings are to be viewed in accordance with the orientation of the reference numerals.

[0010] On Fig. Reference is made to Figure 1. An eccentrically oscillating gear device 10 (hereinafter also referred to simply as a gear device) is installed in a parent machine. The gear device 10 can drive a driven element (not shown) of the parent machine by outputting rotation. The parent machine is, for example, (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) various machines such as vehicles.

[0011] The gear assembly 10 comprises a crankshaft 14 containing eccentric sections 12, oscillating gears 16 that can oscillate due to the eccentric sections 12, a meshing gear 18 that engages with the oscillating gears 16, and eccentric bearings 20 arranged between the eccentric sections 12 and the oscillating gears 16. Furthermore, the gear assembly 10 includes a support 22 mounted on one side of the oscillating gears 16 (a left side in Fig. 1) in an axial direction as a first side element, a cover 24 is provided, which is on the other side of the oscillating gears 16 (a right side in Fig. 1) is provided in the axial direction as a second side element, and a housing 26 that accommodates at least the oscillating gears 16. In the present description, a direction along a rotational centerline of the crankshaft 14 (hereinafter referred to as a crankshaft axis L14) is simply referred to as an axial direction.

[0012] The eccentrically oscillating gear device 10 can axially rotate one of the oscillating gears 16 and the meshing gear 18 by means of the oscillation of the oscillating gears 16 with the rotation of a drive element 28, and can rotate an output element 30 using an axial rotary component thereof. An example in which the crankshaft 14 is the drive element 28 and the support 22 is the output element 30 is described in the present embodiment. Rotation output from an external drive source is input into the drive element 28. The drive source is, for example, a motor, a geared motor, a machine, or the like. The output element 30 outputs rotation to a driven element of an external parent machine.

[0013] The crankshaft 14 comprises at least one eccentric section 12 and shaft sections 32 arranged axially on both sides of the eccentric section 12. A first crankshaft bearing 34A is located between the shaft section 32 located axially on one side of the eccentric section 12 and the support 22. A second crankshaft bearing 34B is located between the shaft section 32 located axially on the other side of the eccentric section 12 and the cover 24. Details of the crankshaft 14 are described later.

[0014] One of the oscillating gear 16 and the meshing gear 18 is an external gear, and the other is an internal gear. In the present embodiment, the oscillating gear 16 is an external gear. Each oscillating gear 16 is mounted by the corresponding eccentric section 12 via the eccentric bearing 20 such that it is rotatable relative to the eccentric section 12. Each oscillating gear 16 has a bearing hole 16a in which the eccentric bearing 20 is to be arranged. The meshing gear 18 of the present embodiment is provided on an inner circumferential section of the housing 26.

[0015] A pin 36 projects axially from the carrier 22 and penetrates the oscillating gears 16. The pin 36 can cause the axial rotational components of the carrier 22 and the oscillating gears 16 to synchronize with each other. In the present embodiment, the pin 36 is in contact with pin holes 16b of the oscillating gears 16 via a roller 38, which is rotatably mounted by the pin 36, but can also be in direct contact with the pin holes 16b.

[0016] The housing 26 accommodates the crankshaft 14, the support 22, and the like, in addition to the oscillating gears 16. The housing 26 of the present embodiment is formed from several housing elements 40 connected to one another by screws or the like, but can also be formed from a single element. One housing element 40 of the present embodiment also serves as the cover 24. A main bearing 42 is arranged between the support 22 and the housing 26.

[0017] On Fig. Reference is made to point 2. Hatching is shown in Fig. 2 has been omitted for the sake of simplicity. Each of the eccentric sections 12 of the crankshaft 14 of the present embodiment is integrally provided as the same element as a central side section that is closer to the crankshaft axis L14 than the eccentric section 12, but may be provided separately from the central side section. The eccentric section 12 has a circular shape, with a central axis L12 eccentric to the crankshaft axis L14. The eccentric section 12 can cause the oscillating gear 16 to oscillate by rotating about the crankshaft axis L14. The term "oscillation" referred to here means that the entire oscillating gear 16 moves such that a central axis L16 of the oscillating gear 16 revolves about an oscillation center Ca.A direction from the crankshaft axis L14 towards the central axis L12 of the eccentric section 12 is referred to as a maximum eccentric direction Da of the eccentric section 12. Furthermore, a direction that is exactly opposite to the maximum eccentric direction Da from the central axis L12 of the eccentric section 12 is referred to as a counter-maximal eccentric direction Db of the eccentric section 12.

[0018] Although the number of eccentric sections 12 in the present embodiment is two, the number is not limited to this and can be one, three, or more. In a case where the number of eccentric sections 12 is set to M, the eccentric phases of the multiple eccentric sections 12 are shifted relative to each other by 360° / M. The eccentric phase mentioned here refers to the phase of the eccentric section 12 in the maximum eccentric direction Da, which is determined based on an angle about the crankshaft axis L14.

[0019] The crankshaft 14 can include a flange section 14c that projects outwards from an outer circumferential section of the crankshaft 14 in a radial direction. In the present embodiment, the flange section 14c is integrally provided as the same element as a central side section that is closer to the crankshaft axis L14 than the flange section 14c, but it can be provided separately from the central side section. The flange section 14c is located between the eccentric sections 12, which are adjacent to each other in an arrangement sequence of the multiple eccentric sections 12.

[0020] Each eccentric bearing 20 contains a roller assembly 52, consisting of several rollers 50. A roller receiving space 54 for receiving the roller assembly 52 is provided between the bearing hole 16a of the oscillating gear 16 and the eccentric section 12. The eccentric bearing 20 is a bearing that does not include a cage for maintaining the relative positions of the several rollers 50. This bearing requires work to be done by individually arranging the several rollers 50 in the roller receiving space 54 at the time of assembly of the gear assembly 10, as described later. A full complement roller bearing that can accommodate the maximum number of rollers 50 that can fill the roller receiving space 54 is used as the bearing in the present embodiment.A bearing that accommodates a number of rollers 50 that is less than the maximum number of rollers 50 that can fill the roller receiving space 54 can also be used as such a bearing in addition to a full complement roller bearing. Furthermore, a bearing in which a spacer is arranged between some adjacent rollers 50 in an arrangement sequence of the multiple rollers 50 can be used as such a bearing.

[0021] Since the space available for the cage can be used as the space available for the rollers in a case where the bearing, which does not contain the cage, is used as the eccentric bearing 20 described above, it is advantageous for ensuring a roller filling ratio. In particular, in a case where the gear assembly 10 is to be reduced in size, there is a manufacturing limit to the size of the cage in one circumferential direction of the crankshaft 14. For this reason, a problem arises in that the roller filling ratio is reduced due to the cage. Since the cage, which causes such a reduction in the roller filling ratio, is omitted, there is an advantage in being able to ensure a roller filling ratio while reducing the size of the gear assembly 10.

[0022] An axis of rotation of the roller 50 of the present embodiment extends along the axial direction. The eccentric bearing 20 of the present embodiment does not include a dedicated inner ring, and an outer circumferential surface of the eccentric section 12 also serves as an inner ring. Furthermore, the eccentric bearing 20 of the present embodiment does not include a dedicated outer ring, and an inner circumferential surface of the bearing hole 16a also serves as an outer ring. Alternatively, the eccentric bearing 20 may include any combination of a dedicated inner ring attached to the outer circumferential surface of the eccentric section 12 and a dedicated outer ring attached to the bearing hole 16a.

[0023] On Fig. 2, Fig. 3A and Fig. Reference is made to Figure 3B. The crankshaft 14 includes receiving sections 60 that can limit the axial movement of the corresponding roller groups 52 by receiving the end faces of the respective rollers 50 of the corresponding roller groups 52. The receiving sections 60 have an overall flat shape perpendicular to the axial direction. The receiving sections 60 comprise a first receiving section 60A and a second receiving section 60B, which faces a side opposite the first receiving section 60A in the axial direction. In the present embodiment, the first receiving section 60A is provided on a side face section of the flange section 14c, and the second receiving section 60B is provided on a side face section of the flange section 14c that faces opposite the first receiving section 60A in the axial direction.

[0024] The roller groups 52 comprise a first roller group 52A, corresponding to the first receiving section 60A, and a second roller group 52B, corresponding to the second receiving section 60B. The first receiving section 60A can limit the axial movement of the corresponding first roller group 52A, and the second receiving section 60B can limit the axial movement of the corresponding second roller group 52B. The eccentric sections 12 comprise a first eccentric section 12A, corresponding to the first receiving section 60A, and a second eccentric section 12B, corresponding to the second receiving section 60B. The first eccentric section 12A and the second eccentric section 12B have different eccentric phases. The oscillating gears 16 include a first oscillating gear 16A corresponding to the first receiving section 60A, and a second oscillating gear 16B corresponding to the second receiving section 60B.The first eccentric section 12A and the first oscillating gear 16A are arranged in the radial direction of the crankshaft 14 at positions that overlap with the first roller group 52A, which corresponds to the corresponding first receiving section 60A. The second eccentric section 12B and the second oscillating gear 16B are arranged in the radial direction of the crankshaft 14 at positions that overlap with the second roller group 52B, which corresponds to the corresponding second receiving section 60B.

[0025] A first pressure element 62A is arranged axially on one side of the first roller group 52A, opposite the first receiving section 60A. The first pressure element 62A limits the axial movement of the first roller group 52A in the axial direction towards the side opposite the first receiving section 60A. A second pressure element 62B is arranged axially on one side of the second roller group 52B, opposite the second receiving section 60B. The second pressure element 62B limits the axial movement of the second roller group 52B in the axial direction towards the side opposite the second receiving section 60B.

[0026] The receiving section 60 contains an eccentric side region 64, which is a semicircular region positioned on one side of the central axis L12 of the corresponding eccentric section 12, corresponding to the maximum eccentric direction Da of the eccentric section 12, and a counter-eccentric side region 66, which is a semicircular region positioned on one side of the central axis L12, corresponding to the counter-maximal eccentric direction Db of the eccentric section 12.

[0027] In the present embodiment, an outer radius R60 in the radial direction of the crankshaft 14 between the crankshaft axis L14 and an outer circumferential end of the receiving section 60 is constant over the entire circumferential range around the crankshaft axis L14. "An outer circumferential end of the receiving section 60," as referred to here, means an outer circumferential end of a section of the receiving section 60 which, in a case where the receiving section 60 receives end faces of the rollers 50 during the operation of arranging the rollers, may be in surface contact with the roller 50.

[0028] A radial direction perpendicular to the central axis L12 of the eccentric section 12 is simply referred to as a radial direction of the eccentric section 12. Furthermore, a dimension in the radial direction of the eccentric section 12 between the central axis L12 of the eccentric section 12, corresponding to the receiving section 60, and the outer circumferential end of the receiving section 60 is referred to as an outer radius dimension L60 of the receiving section 60 based on the eccentric section 12. In the present embodiment, the outer radius dimension L60 of the receiving section 60 based on the eccentric section 12 is smallest in the maximum eccentric direction Da of the eccentric section 12 and largest in the antimaximal eccentric direction Db of the eccentric section 12. The smallest outer radius dimension L60 is in Fig. 2 and Fig. Figure 3 shows the outer radius dimension L60 of the receiving section 60 decreases in the circumferential direction around the central axis L12 of the eccentric section 12 towards the maximum eccentric direction Da gradually from the counter-maximal eccentric direction Db.

[0029] A radius of a circumscribed circle 56 that encircles the roller assembly 52 corresponding to the receiving section 60 is referred to as the circumscribed circular radius R52 of the roller assembly 52. ​​The circumscribed circular radius R52 is constant over the entire circumferential area around the central axis L12 of the eccentric section 12 corresponding to the receiving section 60. The circumscribed circular radius R52 is also an inner radius of a cylindrical rolling contact surface provided on a side closer to the bearing hole 16a than the roller assembly 52, and on which the roller assembly 52 rolls. In the present embodiment, the rolling contact surface is provided in the bearing hole 16a, but can also be provided on an outer ring of the eccentric bearing 20 that is attached to the bearing hole 16a.

[0030] Here, the outer radius dimension L60 of the receiving section 60, based on the eccentric section 12, is larger than the circumscribed circular radius R52 of the roller group 52 corresponding to the receiving section 60, in the maximum eccentric direction Da of the eccentric section 12. Furthermore, the outer radius dimension L60 of the receiving section 60 is larger than the circumscribed circular radius R52 of the roller group 52 corresponding to the receiving section 60, respectively, in the eccentric side region 64 and the counter-eccentric side region 66. A detailed description follows.

[0031] On Fig. Reference is made to 3A. The outer radius dimension L60 of the first receiving section 60A, based on the first eccentric section 12A, is larger than the circumscribed circular radius R52 of the first roller group 52A, corresponding to the first receiving section 60A, in the maximum eccentric direction Da of the first eccentric section 12A. The outer radius dimension L60 of the first receiving section 60A is larger than the circumscribed circular radius R52 of the first roller group 52A in the eccentric side region 64 of the first receiving section 60A. To satisfy this condition, the outer radius dimension L60 can be larger than the circumscribed circular radius R52 in at least a large part of the eccentric side region 64. Furthermore, the outer radius dimension L60 of the first receiving section 60A is larger than the circumscribed circular radius R52 of the first roller group 52A in the counter-eccentric side area 66 of the first receiving section 60A.To satisfy this condition, the outer radius dimension L60 can be larger than the circumscribed circular radius R52 in at least a large part of the counter-eccentric side region 66. The "large part" in this description refers to a circumferential region that is 90% or more of the aforementioned circumferential region around the central axis L12 of the eccentric section 12. In the present embodiment, the outer radius dimension L60 of the first receiving section 60A is set such that it is larger than the circumscribed circular radius R52 in both the entire eccentric side region 64 and the entire counter-eccentric side region 66.

[0032] On Fig. Reference is made to 3B. The outer radius dimension L60 of the second receiving section 60B, based on the second eccentric section 12B, is larger than the circumscribed circular radius R52 of the second roller group 52B, corresponding to the second receiving section 60B, in the maximum eccentric direction Da of the second eccentric section 12B. The outer radius dimension L60 of the second receiving section 60B is larger than the circumscribed circular radius R52 of the second roller group 52B in the eccentric side region 64 of the second receiving section 60B. To satisfy this condition, the outer radius dimension L60 can be larger than the circumscribed circular radius R52 in at least a large part of the eccentric side region 64. Furthermore, the outer radius dimension L60 of the second receiving section 60B is larger than the circumscribed circular radius R52 of the second roller group 52B in the counter-eccentric side area 66 of the second receiving section 60B.To meet this condition, the outer radius dimension L60 can be larger than the circumscribed circular radius R52 in at least a large part of the counter-eccentric side region 66. In the present embodiment, the outer radius dimension L60 of the second receiving section 60B is set such that it is larger than the circumscribed circular radius R52 in both the entire eccentric side region 64 and the entire counter-eccentric side region 66.

[0033] An element that overlaps with the receiving section 60 in the radial direction of the crankshaft 14 and that is located at a position closest to the receiving section 60 is referred to as a nearest element. In the present embodiment, the nearest element is the roller 38 (see Fig. 2), but is not limited to this and can be the pin 36 or the like. The outer radius R60 of each receiving section 60 is smaller than a dimension in the radial direction of the crankshaft 14 between the crankshaft axis L14 of the crankshaft 14, which is provided with the receiving sections 60, and the nearest element, so that contact between each receiving section 60 and the nearest element can be avoided.

[0034] An example of an assembly procedure for the gear assembly 10 described above is described. First, the crankshaft 14 is inserted into the bearing hole 16a of each oscillating gear 16. Then, the rollers 50 are arranged in the roller mounting space 54 between the crankshaft 14 and each oscillating gear 16, so that a gear assembly is obtained (described later). Next, the carrier 22 is mounted to the gear assembly via the first crankshaft bearing 34A. Subsequently, the housing 26 and the carrier 22 are mounted to the gear assembly via the second crankshaft bearing 34B. Accordingly, the gear assembly 10 is assembled.

[0035] In a case where the eccentric bearing 20, which does not contain a cage, is used during the assembly of the gear device 10, the operation of arranging each roller 50 of the roller group 52 in the roller receiving space 54 between the eccentric section 12 of the crankshaft 14 and the oscillating gear 16 is performed. During the operation of arranging the rollers 50, each roller 50 of the roller group 52 is individually positioned in the corresponding roller receiving space 54. The operation of arranging the rollers 50 comprises a first process of arranging each roller 50 of the first roller group 52A in the roller receiving space 54 and a second process of arranging each roller 50 of the second roller group 52B in the roller receiving space 54.

[0036] On Fig. Reference is made to section 4. In the first process, the roll placement work of inserting each roll 50 of the first roll group 52A into the roll receiving space 54 from above and placing the roll 50 onto the first receiving section 60A is performed in a state where the roll receiving space 54 is arranged on the top side of the first receiving section 60A to receive the first roll group 52A. The roll placement work is performed for each of the rolls 50 of the first roll group 52A, so that the first roll group 52A is arranged in the roll receiving space 54. Then, the first pressure element 62A, which limits the axial movement of the first roll group 52A, is arranged such that it prevents the first roll group 52A, arranged in the roll receiving space 54, from falling off.

[0037] Afterwards, although not shown, the second process is carried out after the crankshaft 14 and each oscillating gear 16 are reversed. In the second process, the roller placement operation of inserting each roller 50 of the second roller group 52B into the roller receiving space 54 from above and placing the roller 50 onto the second receiving section 60B is performed in a state where the roller receiving space 54 is arranged on the upper side of the second receiving section 60B to receive the second roller group 52B. The roller placement operation is performed for each of the rollers 50 of the second roller group 52B so that the second roller group 52B is arranged in the roller receiving space 54. Then the second pressure element 62B, which limits the axial movement of the second roller group 52B, is arranged such that it prevents the second roller group 52B from falling out of the roller receiving space 54. Accordingly, the gear arrangement is obtained.

[0038] Next, the background that led to the gear device according to the embodiment of the present disclosure will be described together with the effects of the gear device 10 according to the embodiment of the present embodiment. Fig. Figure 5A is a side cross-sectional view showing a main part of a gear device according to a reference embodiment. Fig. 5B is a cross-sectional view showing part of a cross-section along line CC of Fig. 5A and a first receiving section 60A. The gear device according to the reference embodiment differs from that of the embodiment only with respect to an outer radius dimension L60 of each receiving section 60 of a crankshaft 14.

[0039] In the gear device according to the reference embodiment, as described in Japanese unexamined patent publication No. 2018-119649, the outer radius dimension L60 of a receiving section 60, based on an eccentric section 12, is set such that it is smaller than a circumscribed circular radius R52 of a roller group 52 in a maximum eccentric direction Da of the eccentric section 12. Furthermore, in the gear device according to the reference embodiment, the outer radius dimension L60 of the receiving section 60 is set such that it is smaller than the circumscribed circular radius R52 throughout the entire eccentric side region 64, and is set such that it is smaller than the circumscribed circular radius R52 in a portion of a counter-eccentric side region 66. In this case, as described in Fig. As shown in Figure 6A, the work described above for arranging the rollers 50 is difficult because the roller 50 is placed in a wide area within the eccentric side region 64 of the receiving section 60, which is positioned on a side corresponding to the maximum eccentric direction Da of the eccentric section 12. Consequently, the orientation of the roller 50 is likely to be unstable. For this reason, the roller 50 is likely to be tilted, and therefore likely to tip over.

[0040] The inclination of the roller 50 mentioned here refers, for example, to the inclination of the roller 50 such that a rotational axis L50 of the roller 50 moves further away from a crankshaft axis L14 when the roller 50 moves further away from the receiving section 60 in the axial direction. Fig. Reference is made to Figure 6B. As shown by a two-dot dashed line, the roller 50 is correctly positioned such that its axis of rotation L50 is along the axial direction. The tipping of the roller 50 mentioned here refers to a condition in which the axis of rotation L50 of the roller 50 is substantially parallel to a plane perpendicular to the axial direction, as shown by a solid line. During the operation of arranging the rollers 50, a case is assumed in which a roller receiving space 54 expands at a section corresponding to the maximum eccentric direction Da of the eccentric section 12 due to an amount La of unintended positional misalignment between the central axis L12 of the eccentric section 12 and a central axis L16a of a bearing hole 16a of an oscillating gear 16.In this case, a wide space is created in the roll receiving area 54, which allows the roll 50 to tip over, and it is difficult for the roll 50 to be positioned within a wide area in the eccentric side area 64 of the receiving section 60. For this reason, the problem of the roll 50 tipping over is likely to occur.

[0041] In particular, if the gear assembly 10 is reduced in size, there is a tendency for the roller 50 to tip over due to positional misalignment between the eccentric section 12 and the bearing hole 16a. The reason for this is as follows: If the gear assembly 10 is reduced in size by a reduction in the size of the roller group 52, the space allowing the roller 50 to tip over, caused by the positional misalignment of the eccentric section 12 or the bearing hole 16a, is likely to be larger than the roller 50 in a case where the positional misalignment of the eccentric section 12 and the positional misalignment of the bearing hole 16a occur by the same absolute amount.For example, in the case of a certain size of roller group 52, roller 50 is likely to tip over even if the central axis L12 of the eccentric section 12 and the central axis L16a of the bearing hole 16a are misaligned by 0.1 mm. Furthermore, a problem of roller 50 tipping over is likely to occur in a case where the number of rollers 50 arranged in the roller receiving space 54 is small and the tipping over of roller 50 cannot be limited by the other rollers 50.

[0042] As a countermeasure against the roller 50 tipping over, in the present embodiment the outer radius dimension L60 of the receiving section 60, which is based on the eccentric section 12, is set such that it is larger than the circumscribed circular radius R52 of the roller group 52 in the maximum eccentric direction Da of the eccentric section 12. Accordingly, as in Fig. As shown in Figure 4, it is likely that the roller 50 will be positioned within a wide area of ​​the eccentric side region 64 of the receiving section 60 during the roller arranging operation, as described above, compared to a case where this condition is not met, thus slightly stabilizing the orientation of the roller 50. Consequently, this is advantageous for suppressing the tipping of the roller 50 during the roller arranging operation. For example, although the central axis L12 of the eccentric section 12 and the central axis L16a of the bearing hole 16a in Fig. 4 by the same amount La in positional misalignment as the amount of positional misalignment that is in Fig. As shown in Figure 6, the orientation of the roller 50 is stable because the roller 50 is placed in a wide area of ​​the eccentric side area 64 of the receiving section 60.

[0043] In the present embodiment, the outer radius dimension L60 of the receiving section 60, which is based on the eccentric section 12, is set such that it is larger than the circumscribed circular radius R52 of the roller group 52 in the eccentric side region 64. Accordingly, it is likely that the roller 50 will be positioned on the receiving section 60 within a wider area of ​​the eccentric side region 64 during the roller arranging operation, compared to a case where this condition is not met. Consequently, this may be more advantageous for suppressing the roller 50 from tipping over during the roller arranging operation.

[0044] In the present embodiment, the outer radius dimension L60 of the receiving section 60, which is based on the eccentric section 12, is set such that it is larger than the circumscribed circular radius R52 of the roller group 52 in the counter-eccentric side region 66. Accordingly, it is likely that the roller 50 will be positioned on the receiving section 60 within a wider area encompassing both the eccentric side region 64 and the counter-eccentric side region 66 during the roller arranging operation, compared to a case where this condition is not met. Consequently, this may be more advantageous for suppressing the roller 50 from tipping over during the roller arranging operation.

[0045] In the present embodiment, the outer radius dimension L60 of the first receiving section 60A is larger than the circumscribed circular radius R52 of the first roller group 52A in the maximum eccentric direction Da of the first eccentric section 12A. Furthermore, the outer radius dimension L60 of the second receiving section 60B is larger than the circumscribed circular radius R52 of the second roller group 52B in the maximum eccentric direction Da of the second eccentric section 12B.

[0046] Accordingly, it is likely that the roller 50 will be placed on the first receiving section 60A within a wide area of ​​the eccentric side region 64 of the first receiving section 60A during the process of arranging the rollers 50 belonging to the first roller group 52A, compared to a case where a condition regarding the outer radius dimension L60 of the first receiving section 60A is not met. Consequently, this is advantageous for suppressing the tipping of the roller 50. Furthermore, it is likely that the roller 50 will be placed on the second receiving section 60B within a wide area of ​​the eccentric side region 64 of the second receiving section 60B during the process of arranging the rollers 50 belonging to the second roller group 52B, compared to a case where a condition regarding the outer radius dimension L60 of the second receiving section 60B is not met.Consequently, this is advantageous for suppressing the tipping of the roller 50.

[0047] This means that this is advantageous for suppressing the tipping of the roller 50 itself during the work of arranging the rollers 50 that belong either to the first roller group 52A or to the second roller group 52B.

[0048] The effect described above of advantageously suppressing the tipping of roller 50 is effective in that it is obtained in a case where the gear device 10 is reduced in size by a reduction in the size of the roller group 52. With regard to such an effect, the circumscribed circular radius R52 of the roller group 52 can, for example, be set to 10 mm or less.

[0049] Next, other features of the gear device 10 according to the present embodiment will be described. Fig. Reference is made to Figure 1. The gear assembly 10 includes a spacer 70 that positions the oscillating gears 16 in the axial direction between the carrier 22 and the cover 24. The spacer 70 of the present embodiment includes a first spacer 70A, which is arranged between the first oscillating gear 16A and the second oscillating gear 16B, and a second spacer 70B, which is arranged between the second oscillating gear 16B and the cover 24. The first oscillating gear 16A is positioned in the axial direction by being in contact with the carrier 22 and the first spacer 70A. The second oscillating gear 16B is positioned in the axial direction by being in contact with the first spacer 70A and the second spacer 70B.

[0050] On Fig.Reference is made to section 2. The oscillating gear 16 faces the receiving section 60 in the axial direction and is provided with a gap 72 from the receiving section 60. In particular, the first oscillating gear 16A faces the first receiving section 60A in the axial direction and is provided with a gap 72 from the first receiving section 60A. Furthermore, the second oscillating gear 16B faces the second receiving section 60B in the axial direction and is provided with a gap 72 from the second receiving section 60B. These gaps 72 can be provided between the receiving sections 60 and the oscillating gears 16 over the entire circumferential range around the crankshaft axis L14 of the crankshaft 14.Since the oscillating gears 16 are positioned in the axial direction by the spacer 70 described above, a state is maintained in which the gap 72 is provided in this way between the receiving sections 60 and the oscillating gears 16.

[0051] In the gear device 10 according to the present embodiment, as described above, the outer radius dimension L60 of the receiving section 60, which is based on the eccentric section 12, is set to be large, and the oscillating gear 16 is provided in a position facing the receiving section 60 in the axial direction, within a wide circumferential range around the crankshaft 14. Therefore, if the outer radius dimension L60 of the receiving section 60 is set to be large, as described above, in a state where the oscillating gear 16 and the receiving section 60 are in contact with each other, there is a possibility that a problem such as power loss due to an increase in frictional resistance between the oscillating gear 16 and the receiving section 60 may occur.

[0052] In this respect, the oscillating gear 16 of the present embodiment is provided with a gap 72 in the axial direction from the receiving section 60, which faces the oscillating gear 16 in the axial direction. Therefore, even if the outer radius dimension L60 of the receiving section 60 is increased, an increase in frictional resistance caused by contact between the receiving section 60 and the oscillating gear 16 can be avoided. In particular, in the present embodiment, the first and second oscillating gears 16A and 16B are provided with gaps 72 in the axial direction from the different receiving sections 60A and 60B, which face the first and second oscillating gears 16A and 16B in the axial direction, respectively.Therefore, even in a case where the outer radius dimension L60 of each of the receiving sections 60A and 60B is increased, it is effective in such a way that an increase in frictional resistance caused by contact between each of the receiving sections 60A and 60B and the two first and second oscillating gears 16A and 16B can be avoided.

[0053] Next, modification examples for each component described so far will be presented.

[0054] A central crank type, in which the crankshaft 14 is arranged on the oscillation center Ca of the oscillating gear 16, has been described as a specific type of eccentrically oscillating gear device 10. The type is not particularly restricted, and, for example, a distribution type can be used in which several crankshafts 14 are arranged at positions offset radially from the oscillation center Ca of the oscillating gear 16.

[0055] The housing 26 can be used as the output element 30 instead of the carrier 22. The eccentrically oscillating gear device 10 according to the embodiment has been described as an oscillating gear device with an external tooth, in which an external gear serves as the oscillating gear 16. Alternatively, the eccentrically oscillating gear device 10 can be an oscillating gear device with an internal tooth, in which an internal gear serves as the oscillating gear 16. Although an example has been described in the embodiment in which the gear device 10 functions as a speed reducer, the gear device 10 can also function as a speed increaser. In this case, the carrier 22 or the housing 26 can serve as the drive element 28 instead of the crankshaft 14, and the crankshaft 14 can serve as the output element 30 instead of the carrier 22 or the housing 26.

[0056] The outer radius L60 of the receiving section 60 can be larger than the circumscribed circular radius R52 of the roller group 52 only in the maximum eccentric direction Da of the eccentric section 12 and can be equal to or smaller than the circumscribed circular radius R52 at other sections. Furthermore, the outer radius L60 of the receiving section 60 can be larger than the circumscribed circular radius R52 of the roller group 52 only in the maximum eccentric direction Da of the eccentric section 12 and the counter-eccentric side region 66 and can be equal to or smaller than the circumscribed circular radius R52 at other sections.The outer radius dimension L60 of the first receiving section 60A can be set so that it is larger than the circumscribed circular radius R52 of the first roller group 52A in the maximum eccentric direction Da of the first eccentric section 12A, and the outer radius dimension L60 of the second receiving section 60B can be set so that it is smaller than the circumscribed circular radius R52 of the second roller group 52B in the maximum eccentric direction Da of the second eccentric section 12B.

[0057] The oscillating gear 16 can be in contact with the receiving section 60. To achieve this, the gap 72 can only be provided between the first oscillating gear 16A and the first receiving section 60A, and the second oscillating gear 16B and the second receiving section 60B can be brought into contact with each other. Furthermore, the first oscillating gear 16A can be in contact with the first receiving section 60A, and the second oscillating gear 16B can be in contact with the second receiving section 60B.

[0058] The contents of each component described in the embodiments and the like above are merely examples. The technical idea abstracted from these contents should not be interpreted in a restrictive manner in the contents of this description. The contents of each component described in the embodiments and the like may be modified, added to, removed, or otherwise altered, and many design changes may be made. The description is emphasized by adding the terms "the present embodiment" and "the embodiment" to the contents where such a design change may be made. However, design changes are permissible even for contents where no such expression exists. Any combination of the components described above is also effective.Hatching applied to a cross-section in the drawing does not restrict the material of a hatched object. Structures and numerical values, as mentioned in the embodiments and modification examples, naturally include those that can be considered equivalent, taking into account manufacturing defects and the like. Components described in this document as configured by a single element may be configured by multiple elements. Similarly, a component configured by multiple elements may be configured by a single element. Brief description of the reference symbols 10 eccentrically oscillating gear device 12 eccentric section 12A first eccentric section 12B second eccentric section 14 Crankshaft 16 oscillating gear 16A first oscillating gear 16B second oscillating gear 20 eccentric bearings 50 rolls 52 Role group 52A first role group 52B second role group 60 Reception section 60A first receiving section 60B second receiving section 64 eccentric side area 66 Counter-eccentric side area 72 gap QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2024-195973

[0002] JP 2018-119649 [0003, 0039] US 2018-119649

[0005]

Claims

Eccentrically oscillating gear device (10) comprising: a crankshaft (14) containing eccentric sections (12); oscillating gears (16) capable of oscillating using the eccentric sections (12); and eccentric bearings (20), each of which is arranged between the eccentric section (12) and the oscillating gear (16), wherein the eccentric bearings (20) contain roller groups (52) consisting of several rollers (50) and do not include a cage for holding relative positions of the several rollers (50), the crankshaft (14) contains receiving sections (60) capable of limiting axial movement of the corresponding roller groups (52), the receiving section (60) corresponding to the eccentric section (12) being arranged in a position overlapping with the roller group (52) corresponding to the receiving section (60) in a radial direction of the crankshaft (14),and an outer radius dimension (L60) between a central axis (L12) of the eccentric section (12), corresponding to the receiving section (60), and an outer circumferential end of the receiving section (60) is larger than a circumscribed circular radius (R52) of the roller group (52), corresponding to the receiving section (60), in a maximum eccentric direction (Da) of the eccentric section (12). Eccentrically oscillating gear device (10) according to claim 1, wherein the receiving section (60) includes an eccentric side region (64) which is a semicircular region positioned on one side of the central axis (L12) of the corresponding eccentric section (12) corresponding to the maximum eccentric direction (Da) of the eccentric section (12), and the outer radius dimension (L60) of the receiving section (60) is larger than the circumscribed circular radius (R52) of the roller group (52) corresponding to the receiving section (60) in the eccentric side region (64). Eccentrically oscillating gear device (10) according to claim 2, wherein the receiving section (60) includes a counter-eccentric side region (66) which is a semicircular region positioned on one side of the central axis (L12) of the corresponding eccentric section (12) corresponding to a counter-maximal eccentric direction (Da) of the eccentric section (12), and the outer radius dimension (L60) of the receiving section (60) is larger than the circumscribed circular radius (R52) of the roller group (52) corresponding to the receiving section (60) in the counter-eccentric side region (66). Eccentrically oscillating gear device (10) according to claim 1, wherein the receiving sections (60) comprise a first receiving section (60A) and a second receiving section (60B) facing a side opposite the first receiving section (60A) in an axial direction, the roller groups (52) comprise a first roller group (52A) of which the axial movement is limited by the first receiving section (60A), and a second roller group (52B) of which the axial movement is limited by the second receiving section (60B), the eccentric sections (12) comprise a first eccentric section (12A) corresponding to the first receiving section (60A), and a second eccentric section (12B) corresponding to the second receiving section (60B),an outer radius dimension (L60) between a central axis (L12) of the first eccentric section (12A) and an outer circumferential end of the first receiving section (60A) is larger than a circumscribed circular radius (R52) of the first roller group (52A) in a maximum eccentric direction (Da) of the first eccentric section (12A), and an outer radius dimension (L60) between a central axis (L12) of the second eccentric section (12B) and an outer circumferential end of the second receiving section (60B) is larger than a circumscribed circular radius (R52) of the second roller group (52B) in a maximum eccentric direction (Da) of the second eccentric section (12B). Eccentrically oscillating gear device (10) according to claim 1, wherein the oscillating gear (16) is directed towards the receiving section (60) in an axial direction and is provided with a gap (72) from the receiving section (60). Eccentrically oscillating gear device (10) according to claim 5, wherein the receiving sections (60) comprise a first receiving section (60A) and a second receiving section (60B) which faces a side opposite the first receiving section (60A) in the axial direction, the oscillating gears (16) comprise a first oscillating gear (16A) which faces the first receiving section (60A) in the axial direction, and a second oscillating gear (16B) which faces the second receiving section (60B) in the axial direction, the first oscillating gear (16A) being provided with a gap (72) from the first receiving section (60A), and the second oscillating gear (16B) being provided with a gap (72) from the second receiving section (60B).

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