Speed reducer with small tooth difference

Abstract

The small-tooth-difference speed reducer comprises an input flange, a uniform load ring, an inner gear ring, a connecting bearing, a planet wheel and a pin shaft, the pin shaft comprises a core shaft part and an outer shaft sleeve part installed on the core shaft part, and the parts, extending out of the outer shaft sleeve part, of the two ends of the core shaft part are a first connecting shaft section and a second connecting shaft section respectively. The first connecting shaft section extends into an inner ring of the connecting bearing, the second connecting shaft section extends into the uniform load ring, the first connecting shaft section of the pin shaft is fixedly connected with the inner ring of the connecting bearing, and the second connecting shaft section of the pin shaft is fixedly connected with the uniform load ring; or, the inner ring of the connecting bearing and the input flange are fixedly connected with the inner gear ring, an input flange bearing is arranged between the input flange and the uniform load ring, and the input flange applies pressing force towards one side of the output flange to the outer ring of the input flange bearing. And the inner ring of the input flange bearing applies a pressing force towards one side of the output flange to the uniform load ring.

Description

Technical Field

[0001] The utility model relates to the technical field of speed reducers, in particular to a speed reducer with a small tooth difference. Background Art

[0002] A small-tooth-difference reducer is a mechanical device that uses a small difference in the number of teeth between gears to achieve speed reduction. It boasts simple structure, reliable transmission, and high efficiency, and has been widely used in various industrial fields. Traditional pin-type output small-tooth-difference reducers, while widely used in industries like chemical and hoisting, are too large to be installed on robots. Furthermore, traditional structures no longer meet the robots' requirements for high rigidity, high load capacity, and low backlash.

[0003] The utility model patent with application number CN202123354972.5 discloses a new type of small-tooth difference reducer for robots, including a cross bearing, an input flange and an output flange. An eccentric part is sleeved on the input shaft or two or more eccentric parts are arranged in parallel along the axial direction. A swing arm bearing is sleeved on the outside of each eccentric part. Several planetary gears are evenly arranged along the circumference of the outside of the input shaft. A connecting swing assembly for the eccentric swing of the planetary gear is arranged in the middle of each planetary gear. One end of the connecting swing assembly is connected to the cross bearing, and the other end contacts the input flange through a support assembly. The connecting swing assembly and the support assembly rotate around the input shaft; an inner ring gear is arranged between the cross bearing and the input flange, and the inner ring gear is matched with the planetary gear. The output flange is installed on the outer end face of the cross bearing. In this type of small-tooth-difference reducer, it is necessary to ensure stable axial fit, especially the fit between the cross bearing, inner gear ring and load-balancing ring. Without axial locking, it is necessary to design bearings and other structures for axial support and limitation. Therefore, there will be a slight axial movement, which will make the axial thickness of the small-tooth-difference reducer relatively large, and the axial rigidity of the reducer is not high, and the weight is also relatively large, which makes it difficult to meet the robot's high dimensional accuracy, large load and high rigidity requirements. Utility Model Content

[0004] In view of the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a small-tooth difference reducer with stable axial connection, high rigidity, and smaller axial size.

[0005] To achieve the above-mentioned purpose, the utility model provides a small-tooth difference reducer, including an input flange, a load-balancing ring, an inner gear ring, a connecting bearing, a planetary gear and a pin shaft, wherein the pin shaft includes a core shaft portion and an outer shaft sleeve portion, the outer shaft sleeve portion is sleeved on the core shaft portion, and the two ends of the core shaft portion extend out of the outer shaft sleeve portion, respectively, and are a first connecting shaft segment and a second connecting shaft segment, the outer shaft sleeve portion is fixed to the core shaft portion or can move axially relative to the core shaft portion, the end face of the outer shaft sleeve portion facing the first connecting shaft segment constitutes a first shaft shoulder surface, and the first shaft shoulder surface is used to directly or indirectly abut and position the inner ring of the connecting bearing, and the outer shaft sleeve portion faces the second connecting shaft segment. The end face is a second shoulder surface, and the second shoulder surface is used to directly or indirectly abut and position the load-balancing ring. The pin passes through the planetary gear, and the planetary gear is located on the outer sleeve. The first connecting shaft section of the pin is fixedly connected to the inner ring of the connecting bearing, and the second connecting shaft section is fixedly connected to the load-balancing ring; or, the outer ring and the input flange of the connecting bearing are respectively fixedly connected to the inner gear ring, an input flange bearing is provided between the input flange and the load-balancing ring, and the input flange applies a clamping force toward the output flange on the outer ring of the input flange bearing, and the inner ring of the input flange bearing applies a clamping force toward the output flange on the load-balancing ring.

[0006] Furthermore, the outer ring and the input flange of the connecting bearing are respectively fixedly connected to the inner gear ring, an input flange bearing is provided between the input flange and the load-balancing ring, and the input flange applies a clamping force toward the output flange on the outer ring of the input flange bearing, and the inner ring of the input flange bearing applies a clamping force toward the output flange on the load-balancing ring; a first pressing surface is provided on the inner hole surface of the input flange, a second pressing surface is provided on the outer peripheral surface of the outer ring of the input flange bearing, and the first pressing surface is pressed on the second pressing surface; a third pressing surface is provided on the inner hole surface of the inner ring of the input flange bearing, a fourth pressing surface is provided on the outer peripheral surface of the load-balancing ring, and the third pressing surface is pressed on the fourth pressing surface.

[0007] Furthermore, it also includes an output flange, which is fixedly connected to the inner ring of the connecting bearing, the first connecting shaft section of the pin is fixedly connected to the inner ring of the connecting bearing or fixedly connected to the output flange, and the second connecting shaft section is fixedly connected to the load-balancing ring.

[0008] Furthermore, a first compression nut and a second compression nut are respectively threaded onto the first connecting shaft section and the second connecting shaft section of the pin shaft, the first compression nut is pressed onto the inner ring or output flange of the connecting bearing, and the second compression nut is pressed onto the load-balancing ring; or, a first screw is threaded onto the end face of the first connecting shaft section of the pin shaft, and the nut of the first screw is pressed onto the inner ring or output flange of the connecting bearing, and a second screw is threaded onto the end face of the second connecting shaft section of the pin shaft, and the nut of the second screw is pressed onto the load-balancing ring.

[0009] Further, the first connecting shaft section of the pin shaft is fixedly connected with the inner ring of the connecting bearing or the output flange by means of thread connection, welding, gluing or interference fit, and the second connecting shaft section is fixedly connected with the load sharing ring by means of thread connection, welding, gluing or interference fit.

[0010] Further, an intermediate force transmission flange is arranged between the inner ring of the connecting bearing and the outer sleeve part of the pin shaft, and the intermediate force transmission flange is in abutting contact with the inner ring of the connecting bearing and the first shaft shoulder face at two ends thereof; the first connecting shaft section of the pin shaft passes through the intermediate force transmission flange and is fixedly connected with the output flange.

[0011] Further, an input shaft and a swing arm bearing are further included, the input shaft is fixedly provided with an eccentric part, the planetary gears are installed on the eccentric part through the swing arm bearing, the swing arm bearing is a cylindrical roller bearing, the planetary gears are fixedly connected with the bearing outer ring of the swing arm bearing or are integrated, and the bearing inner ring of the swing arm bearing is fixedly connected with the eccentric part or is integrated.

[0012] Further, the bearing inner ring and the bearing outer ring of the swing arm bearing have cylindrical rollers therebetween; the two ends of the bearing outer ring are provided with fixed blocking edges for blocking the cylindrical rollers, one end of the bearing inner ring is provided with a fixed blocking edge for blocking the cylindrical rollers, and the other end is provided with a movable blocking edge for blocking the cylindrical rollers; or one end of the bearing outer ring is provided with a fixed blocking edge for blocking the cylindrical rollers, and the other end is not provided with a blocking edge or is provided with a movable blocking edge for blocking the cylindrical rollers, and both ends of the bearing inner ring are provided with fixed blocking edges for blocking the cylindrical rollers.

[0013] Further, the bearing inner ring and the bearing outer ring of the swing arm bearing have cylindrical rollers therebetween; two planetary gears are installed on the eccentric part through one swing arm bearing respectively, and the two planetary gears are directly or indirectly in abutting contact; both ends of the bearing outer ring of the swing arm bearing are provided with fixed blocking edges for blocking the cylindrical rollers, or the bearing outer ring is provided with a fixed blocking edge for blocking the cylindrical rollers on one side facing the other swing arm bearing, and is not provided with a blocking edge on the other side; the bearing inner ring of the swing arm bearing is provided with a fixed blocking edge for blocking the cylindrical rollers on a side facing away from the other swing arm bearing.

[0014] As described above, the few-tooth difference speed reducer has the following beneficial effects:

[0015] By fixing the two ends of the pin shaft to the load-balancing ring and the connecting bearing respectively, or by fixing the outer ring of the connecting bearing and the input flange to the inner gear ring, and pressing the pin shaft through the input flange bearing and the load-balancing ring, the inner ring of the connecting bearing and the load-balancing ring can be axially fixedly connected, and the swing arm bearing, pin shaft, planetary gear and other structures located between the connecting bearing and the load-balancing ring can also remain stable, reducing axial movement. The entire small-tooth difference reducer can be tightly compressed in the axial direction, and the output flange, load-balancing ring, etc. are all axially fixed. There is no need to design bearing support and axial positioning on the right side (the side where the input flange is located), reducing the pressure load on the right side, simplifying the structure, and making the axial dimension of the entire small-tooth difference reducer smaller. It is particularly suitable for use in high dimensional precision, large load and high rigidity occasions such as robots. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural diagram of Example 1 of a small-tooth-difference reducer of the present utility model.

[0017] Figure 2 This is a structural diagram of the second embodiment of the small-tooth-difference reducer of the present utility model.

[0018] Figure 3 This is a structural diagram of the third embodiment of the small-tooth-difference reducer of the present utility model.

[0019] Figure 4 This is a structural diagram of a fourth embodiment of a small-tooth-difference reducer of the present utility model.

[0020] Figure 5 This is a structural diagram of the fifth embodiment of the small-tooth-difference reducer of the present utility model.

[0021] Figure 6 This is a structural diagram of Example 6 of the small-tooth difference reducer of the present utility model.

[0022] Figure 7 This is a structural diagram of Example 7 of the small-tooth-difference reducer of the present utility model.

[0023] Figure 8 This is a structural diagram of Example 8 of a small-tooth-difference reducer of the present utility model.

[0024] Figure 9 It is a structural schematic diagram of the pin shaft in the present utility model.

[0025] Figure 10 This is a structural diagram of a first embodiment of the swing arm bearing in the present utility model.

[0026] Figure 11 This is a structural diagram of a second embodiment of the swing arm bearing in the present utility model.

[0027] Figure 12 This is a schematic diagram of the installation of the spacer in the present invention.

[0028] Figure 13 This is a schematic diagram of the installation of the spacer in the present invention.

[0029] Figure 14 This is a structural diagram of the third embodiment of the swing arm bearing in the present utility model.

[0030] Explanation of Figure Numbers

[0031] 1 Input shaft

[0032] 2 Input flange

[0033] 3 Load-balancing rings

[0034] 4 Internal gear ring

[0035] 5 Connecting bearings

[0036] 6 Output flange

[0037] 7 pin

[0038] 701 outer sleeve

[0039] 702 first connecting shaft segment

[0040] 703 Second connecting shaft segment

[0041] 704 First shoulder surface

[0042] 705 Second axis shoulder surface

[0043] 8 planetary gears

[0044] 9 Input flange bearing

[0045] 10 Swing arm bearing

[0046] 101 bearing outer ring

[0047] 102 bearing inner ring

[0048] 103 Cylindrical Roller

[0049] 104 fixed ribs

[0050] 105 movable rib

[0051] 11 Eccentric part

[0052] 12 Roller bearings

[0053] 13 First crimping nut

[0054] 14 Second compression nut

[0055] 15 Pin Bushing

[0056] 16 First screw

[0057] 17 Second screw

[0058] 18 Intermediate force transmission flange

[0059] 19 Spacer DETAILED DESCRIPTION

[0060] The following describes the implementation of the present invention through specific embodiments. People familiar with this technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0061] It should be noted that the structures, proportions, sizes, etc. depicted in the drawings of this specification are only used to match the contents disclosed in this specification for the understanding and reading of those familiar with this technology, and are not used to limit the conditions for the implementation of this utility model. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed in this utility model without affecting the efficacy and purpose of the utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle", etc. quoted in this specification are only for the convenience of description and are not used to limit the scope of the implementation of this utility model. Changes or adjustments in their relative relationships should also be considered as the scope of the implementation of this utility model without substantially changing the technical content.

[0062] See also Figures 1 to 14 The utility model provides a small-tooth difference reducer, including an input flange 2, a load-balancing ring 3, an inner gear ring 4, a connecting bearing 5, an output flange 6, a planetary gear 8 and a pin shaft 7. The pin shaft 7 includes a core shaft portion and an outer shaft sleeve portion 701. The outer shaft sleeve portion 701 is sleeved on the core shaft portion, and the parts at both ends of the core shaft portion extending from the outer shaft sleeve portion 701 are respectively a first connecting shaft segment 702 and a second connecting shaft segment 703. The outer shaft sleeve portion 701 is fixed to the core shaft portion or can be axially moved relative to the core shaft portion. The outer shaft sleeve portion 701 is directed toward the core shaft portion. The end face of a connecting shaft segment 702 constitutes a first shoulder surface 704. During assembly, the first shoulder surface 704 directly or indirectly abuts against the inner ring of the connecting bearing 5 to achieve axial positioning. The end face of the outer sleeve portion 701 facing the second connecting shaft segment 703 is a second shoulder surface 705. During assembly, the second shoulder surface 705 directly or indirectly (for example, through a washer) abuts against the load-balancing ring 3 to achieve axial positioning. The pin shaft 7 passes through the planetary gear 8, and the planetary gear 8 is located on the outer sleeve portion 701. The above is a conventional structure of a small-tooth difference reducer.

[0063] The improvement in the present invention is that the first connecting shaft section 702 of the pin shaft 7 is fixedly connected to the inner ring of the connecting bearing 5, and the second connecting shaft section 703 is fixedly connected to the load-balancing ring 3; or, the outer ring of the connecting bearing 5 and the input flange 2 are respectively fixedly connected to the inner gear ring 4, an input flange bearing 9 is provided between the input flange 2 and the load-balancing ring 3, and the input flange 2 applies a clamping force toward the output flange 6 on the outer ring of the input flange bearing 9, and the inner ring of the input flange bearing 9 applies a clamping force toward the output flange 6 on the load-balancing ring 3. At this time, the first connecting shaft section 702 of the pin shaft 7 is not fixedly connected to the inner ring of the connecting bearing 5, and the second connecting shaft section 703 is not fixedly connected to the load-balancing ring 3. Under the action of the clamping force, the load-balancing ring 3 can be pressed on the second shoulder surface 705 of the pin shaft 7, and at the same time, the first shoulder surface 704 of the pin shaft 7 is pressed on the inner end face of the inner ring of the connecting bearing 5. Through the above two methods, an axial fixed connection can be achieved between the connecting bearing 5 and the load-balancing ring 3. The structures such as the swing arm bearing 10, the pin 7, and the planetary gear 8 located between the connecting bearing 5 and the load-balancing ring 3 can also remain stable, reducing axial movement. The entire small-tooth differential reducer can be tightly compressed in the axial direction, and the output flange 6, the load-balancing ring 3, etc. are all axially stable. It is no longer necessary to design bearing supports and axial positioning on the right side (the side where the input flange 2 is located), reducing the pressure load on the right side, simplifying the structure, and making the axial size of the entire small-tooth differential reducer smaller. It is particularly suitable for use in high dimensional accuracy, large loads, and high rigidity applications such as robots. The connecting bearing 5 is preferably a cross bearing or a four-point contact ball bearing. Of course, other suitable bearing structures can also be used.

[0064] See also Figures 1 to 14 The present invention is further described below with reference to several specific embodiments:

[0065] Example 1:

[0066] See also Figure 1In the embodiment, the small tooth difference reducer comprises an input shaft 1, an input flange 2, a load sharing ring 3, an inner gear ring 4, a connecting bearing 5, an output flange 6, a planetary gear 8, a pin shaft 7 and the like, wherein the connecting bearing 5 is preferably a cross roller bearing. The small tooth difference reducer is internally provided with the input shaft 1, the input shaft 1 is axially provided with two eccentric parts 11, the eccentric part 11 is preferably an integral structure with the input shaft 1, and the eccentric part 11 can also be fixedly connected to the input shaft 1. Each eccentric part 11 is externally provided with a swing arm bearing 10, the input shaft 1 is externally provided with two planetary gears 8 in parallel, each planetary gear 8 is internally provided with a plurality of pin shafts 7, and the pin shaft 7 is provided with a roller bearing 12 between the planetary gear 8. The pin shaft 7 comprises a core shaft part and an outer shaft sleeve part 701, the outer shaft sleeve part 701 is sleeved on the core shaft part, the core shaft part is provided with a first connecting shaft segment 702 and a second connecting shaft segment 703 which are respectively extended from the outer shaft sleeve part 701, the outer shaft sleeve part 701 is fixed to the core shaft part and can also be axially movable relative to the core shaft part. The end face of the outer shaft sleeve part 701 towards the first connecting shaft segment 702 forms a first shaft shoulder face 704, the first shaft shoulder face 704 is directly or indirectly abutted against the inner ring of the connecting bearing 5 to realize axial positioning during assembly, and the end face of the outer shaft sleeve part 701 towards the second connecting shaft segment 703 is a second shaft shoulder face 705. The planetary gear 8 is installed on the outer shaft sleeve part 701 of the pin shaft 7. The inner gear ring 4 is arranged between the connecting bearing 5 and the input flange 2, the inner gear ring 4 is connected with the planetary gear 8, the output flange 6 is fixedly arranged on the outer end face of the inner ring of the connecting bearing 5, and preferably, the inner ring of the connecting bearing 5 and the output flange 6 are integrated.

[0067] In the embodiment, referring to Figure 1 , the outer ring of the connecting bearing 5 and the input flange 2 are respectively fixedly connected with the inner gear ring 4, and the input flange 2 and the load sharing ring 3 are provided with an input flange bearing 9, the load sharing ring 3 is relatively rotatable with the input flange 2 through the input flange bearing 9, the input flange 2 is pressed against the load sharing ring 3 through the input flange bearing 9, the input flange 2 applies a pressing force to the outer ring of the input flange bearing 9 towards the output flange 6 side, the inner ring of the input flange bearing 9 applies a pressing force to the load sharing ring 3 towards the output flange 6 side, so that the load sharing ring 3 is pressed against the second shaft shoulder face 705 of the pin shaft 7, and the first shaft shoulder face 704 of the pin shaft 7 is pressed against the inner side end face of the inner ring of the connecting bearing 5, so that the pin shaft 7 is well positioned and pressed. The first connecting shaft is a smooth shaft segment, the outer circumferential surface of which is smooth and gap-fitted with the shaft hole in the inner ring of the connecting bearing 5, and the second connecting shaft is also a smooth shaft segment, the outer circumferential surface of which is smooth and gap-fitted with the shaft hole in the load sharing ring 3.

[0068] In the embodiment, referring to Figure 1The input flange 2 has a first pressing surface on its inner surface, and the input flange bearing 9 has a second pressing surface on its outer circumferential surface. The first pressing surface is pressed against the second pressing surface, forming a press-fit structure. Similarly, the input flange bearing 9 has a third pressing surface on its inner surface, and the load-balancing ring 3 has a fourth pressing surface on its outer circumferential surface. The third pressing surface is pressed against the fourth pressing surface, forming a press-fit structure. In other embodiments, the input flange 2 may apply a pressing force to the outer ring of the input flange bearing 9 toward the output flange 6 using other suitable methods, and the inner ring of the input flange bearing 9 may apply a pressing force to the load-balancing ring 3 toward the output flange 6 using other suitable methods.

[0069] During operation of the small-tooth-difference reduction gearbox of this embodiment, input shaft 1 rotates, causing load ring 3, pin 7, and planetary gear 8 to rotate about input shaft 1. Planetary gear 8 then orbits, causing pin 7 to drive the inner ring of connecting bearing 5 to rotate about input shaft 1. This, in turn, drives the inner ring of connecting bearing 5 to rotate output flange 6. The basic operating principle of the small-tooth-difference reduction gearbox is well-known and will not be further described.

[0070] Example 2:

[0071] See also Figure 2 In this embodiment, the small-tooth-difference reducer includes an input shaft 1, an input flange 2 (not shown in the figure), a load-balancing ring 3, an inner gear ring 4, a connecting bearing 5, an output flange 6, planetary gears 8, and a pin 7. The connecting bearing 5 is preferably a cross bearing. An input shaft 1 is disposed in the middle of the small-tooth-difference reducer. Two eccentric portions 11 are axially arranged side by side on the input shaft 1. The eccentric portions 11 are preferably an integral structure with the input shaft 1. The eccentric portions 11 can also be fixedly connected to the input shaft 1. A swing arm bearing 10 is sleeved on the outside of each eccentric portion 11. Two planetary gears 8 are arranged side by side on the outside of the input shaft 1. Each planetary gear 8 is internally provided with a plurality of pins 7. A roller bearing 12 is provided between the pins 7 and the planetary gears 8. The pin 7 comprises a core shaft portion and an outer sleeve portion 701. The outer sleeve portion 701 is fitted onto the core shaft portion. The ends of the core shaft portion extending from the outer sleeve portion 701 are respectively a first connecting shaft segment 702 and a second connecting shaft segment 703. The outer sleeve portion 701 is fixed to the core shaft portion, or it may be axially movable relative to the core shaft portion. The end surface of the outer sleeve portion 701 facing the first connecting shaft segment 702 forms a first shoulder surface 704. During assembly, the first shoulder surface 704 directly or indirectly abuts against the inner ring of the connecting bearing 5 to achieve axial positioning. The end surface of the outer sleeve portion 701 facing the second connecting shaft segment 703 forms a second shoulder surface 705. Planetary gears 8 are mounted on the outer sleeve portion 701 of the pin 7. The inner gear ring 4 is positioned between the connecting bearing 5 and the input flange 2, and is mated with the planetary gears 8. The output flange 6 is fixedly mounted on the outer end surface of the inner ring of the connecting bearing 5.

[0072] In this embodiment, see Figure 2 The outer end of the first connecting shaft section 702 of the pin shaft 7 is provided with an external thread section, and is threaded with a first pressing nut 13. The first pressing nut 13 is pressed against the inner ring of the connecting bearing 5, and the first shoulder surface 704 of the pin shaft 7 is pressed against the inner end surface of the inner ring of the connecting bearing 5, thereby realizing the fixed connection between the first connecting shaft section 702 and the inner ring of the connecting bearing 5. The rest of the first connecting shaft section 702 is a smooth shaft section, the outer peripheral surface of which is smooth and is clearance-matched with the shaft hole in the inner ring of the connecting bearing 5. The outer end of the second connecting shaft section 703 of the pin shaft 7 is provided with an external threaded section, and is threaded with a second pressing nut 14. The second pressing nut 14 is pressed against the outer end face of the load-balancing ring 3, and the second shoulder surface 705 of the pin shaft 7 is pressed against the inner end face of the load-balancing ring 3, thereby realizing the fixed connection between the first connecting shaft section 702 and the load-balancing ring 3. The rest of the second connecting shaft section 703 is a smooth shaft section, the outer peripheral surface of which is smooth and is clearance-matched with the shaft hole in the load-balancing ring 3.

[0073] The second press nut 14 is preferably sunk into a groove in the outer end face of the inner ring of the connecting bearing 5 .

[0074] In this embodiment, the small-tooth-difference reduction gearbox rotates when the input shaft 1 rotates, causing the equalizer ring 3, pin 7, and planetary gear 8 to rotate about the input shaft 1. The planetary gear 8 then orbits, and the pin 7 drives the inner ring of the connecting bearing 5 to rotate about the input shaft 1. The inner ring of the connecting bearing 5 is fixedly connected to the output flange 6, driving the rotation of the output flange 6. The principle of the small-tooth-difference reduction gearbox is well known and will not be described in detail.

[0075] Example 3:

[0076] See also Figure 3In this embodiment, the small-tooth-difference reducer includes an input shaft 1, an input flange 2 (not shown in the figure), a load-balancing ring 3, an inner gear ring 4, a connecting bearing 5, an output flange 6, planetary gears 8, and a pin 7. The connecting bearing 5 is preferably a cross bearing. An input shaft 1 is provided in the middle of the small-tooth-difference reducer. Two eccentric portions 11 are axially arranged side by side on the input shaft 1. The eccentric portions 11 are preferably an integral structure with the input shaft 1. The eccentric portions 11 can also be fixedly connected to the input shaft 1. A swing arm bearing 10 is sleeved on the outside of each eccentric portion 11. Two planetary gears 8 are arranged side by side on the outside of the input shaft 1. Each planetary gear 8 is provided with a plurality of pins 7 inside. A pin sleeve 15 is provided between the pin 7 and the planetary gear 8. The pin 7 comprises a core shaft portion and an outer sleeve portion 701. The outer sleeve portion 701 is fitted onto the core shaft portion. The ends of the core shaft portion extending from the outer sleeve portion 701 are respectively a first connecting shaft segment 702 and a second connecting shaft segment 703. The outer sleeve portion 701 is fixed to the core shaft portion, or it may be axially movable relative to the core shaft portion. The end surface of the outer sleeve portion 701 facing the first connecting shaft segment 702 forms a first shoulder surface 704. During assembly, the first shoulder surface 704 directly or indirectly abuts against the inner ring of the connecting bearing 5 to achieve axial positioning. The end surface of the outer sleeve portion 701 facing the second connecting shaft segment 703 forms a second shoulder surface 705. Planetary gears 8 are mounted on the outer sleeve portion 701 of the pin 7. The inner gear ring 4 is positioned between the connecting bearing 5 and the input flange 2, and is mated with the planetary gears 8. The output flange 6 is fixedly mounted on the outer end surface of the inner ring of the connecting bearing 5.

[0077] In this embodiment, see Figure 3 The outer end of the first connecting shaft section 702 of the pin 7 is provided with an external threaded section and is directly threaded into the output flange 6. Since the output flange 6 and the inner ring of the connecting bearing 5 are fixedly connected or integral, this is equivalent to the first connecting shaft section 702 being threaded into the inner ring of the connecting bearing 5. At the same time, the first shoulder surface 704 of the pin 7 is pressed against the inner end surface of the inner ring of the connecting bearing 5, thereby achieving a fixed connection between the first connecting shaft section 702 and the inner ring of the connecting bearing 5. The remaining portion of the first connecting shaft section 702 is a smooth shaft section with a smooth outer circumference that is clearance-matched with the axial hole in the inner ring of the connecting bearing 5. The outer end of the second connecting shaft section 703 of the pin 7 is also provided with an external thread section, and is threaded with a second compression nut 14. The second compression nut 14 is pressed against the outer end face of the load-balancing ring 3, and the second shoulder surface 705 of the pin 7 is pressed against the inner end face of the load-balancing ring 3, thereby achieving a fixed connection between the first connecting shaft section 702 and the load-balancing ring 3. The remaining portion of the second connecting shaft section 703 is a smooth shaft section with a smooth outer circumference and a clearance fit with the axial hole in the load-balancing ring 3. The motion principle of the small tooth difference reduction in this embodiment is the same as that in the second embodiment and will not be described in detail.

[0078] Example 4:

[0079] See also Figure 4 The small-tooth-difference reducer in this embodiment is basically the same as that in the third embodiment described above, except that different connection methods are used at both ends of the pin 7. The first connecting shaft segment 702 is directly fixedly connected to the inner ring of the connecting bearing 5 by welding, bonding (rigid strength adhesive), or interference fit. Of course, it can also be fixedly connected to the output flange 6, and the first shoulder surface 704 of the pin 7 is pressed against the inner end face of the inner ring of the connecting bearing 5. The second connecting shaft segment 703 is also directly fixedly connected to the load-balancing ring 3 by welding, bonding (rigid strength adhesive), or interference fit, and the second shoulder surface 705 of the pin 7 is pressed against the inner end face of the load-balancing ring 3. The other parts of this embodiment are the same as those in the third embodiment described above and will not be repeated.

[0080] Embodiment 5:

[0081] See also Figure 5 The small-tooth differential reducer in this embodiment is basically the same as that in the third embodiment described above, except that different connection methods are used at both ends of the pin shaft 7, wherein a first screw 16 is threaded onto the end face of the first connecting shaft section 702 of the pin shaft 7, and the nut of the first screw 16 is pressed against the outer end face of the output flange 6, and the first shoulder surface 704 of the pin shaft 7 is pressed against the inner end face of the inner ring of the connecting bearing 5. Of course, the nut of the first screw 16 can also be pressed against the inner ring of the connecting bearing 5. A second screw 17 is threaded onto the end face of the second connecting shaft section 703 of the pin shaft 7, and the nut of the second screw 17 is pressed against the load-balancing ring 3, and the second shoulder surface 705 of the pin shaft 7 is pressed against the inner end face of the load-balancing ring 3. The other parts of this embodiment are the same as those in the third embodiment described above and will not be repeated.

[0082] Example 6:

[0083] See also Figure 6The small-tooth-difference reducer in this embodiment is essentially the same as that in the second embodiment described above, differing in that an intermediate force-transmission flange 18 is provided between the inner ring of the connecting bearing 5 and the outer sleeve portion 701 of the pin 7. The inner ring of the connecting bearing 5 and the intermediate force-transmission flange 18 are two separate components, as are the inner ring of the connecting bearing 5 and the output flange 6. During assembly, the first connecting shaft segment 702 of the pin 7 passes through the intermediate force-transmission flange 18. The first shoulder surface 704 of the outer sleeve portion 701 is pressed against the right end face of the intermediate force-transmission flange 18 (the side facing the input flange 2) via a washer (or directly), thereby pressing the left side of the intermediate force-transmission flange 18 against the inner ring of the connecting bearing 5. Specifically, mating pressing surfaces are provided on the outer circumferential surface of the intermediate force-transmission flange 18 and the inner bore surface of the inner ring of the connecting bearing 5. Simultaneously, the output flange 6 is axially pressed against the left end face of the inner ring of the connecting bearing 5 by the tightening action of the first compression nut 13 and the first connecting shaft segment 702. In this way, the radial dimension of the inner ring of the connecting bearing 5 is small, and the connecting bearing 5 can be selected from conventional models on the market, and its inner ring radial thickness is small, which reduces the manufacturing cost. The other parts of this embodiment are the same as those in the above embodiment 2 and will not be repeated here.

[0084] Embodiment seven:

[0085] See also Figure 7 The small-tooth-difference reducer in this embodiment is essentially the same as that in the third embodiment described above, differing in that an intermediate force-transmission flange 18 is provided between the inner ring of the connecting bearing 5 and the outer sleeve portion 701 of the pin 7. The inner ring of the connecting bearing 5 and the intermediate force-transmission flange 18 are two separate structures, and the inner ring of the connecting bearing 5 and the output flange 6 are also two separate structures. During assembly, the first connecting shaft section 702 of the pin 7 passes through the intermediate force-transmission flange 18. The first shoulder surface 704 of the outer sleeve portion 701 is pressed against the right end face (facing the input flange 2) of the intermediate force-transmission flange 18 via a gasket (or directly), thereby pressing the left side of the intermediate force-transmission flange 18 against the inner ring of the connecting bearing 5. Specifically, mating pressing surfaces are provided on the outer circumferential surface of the intermediate force-transmission flange 18 and the inner bore surface of the inner ring of the connecting bearing 5. Simultaneously, through the fastening action (including threading, interference fit, adhesive bonding, or welding) between the output flange 6 and the first connecting shaft segment 702, the output flange 6 is also axially pressed against the left end face of the inner ring of the connecting bearing 5. This approach reduces the radial dimension of the inner ring of the connecting bearing 5, enabling the use of conventional commercially available models with a reduced radial thickness, thereby reducing manufacturing costs. The remaining components of this embodiment are identical to those of the second embodiment and will not be further elaborated.

[0086] Embodiment 8:

[0087] See also Figure 8The small-tooth-difference reducer in this embodiment is essentially the same as that in the fifth embodiment described above, except that an intermediate force-transmission flange 18 is provided between the inner ring of the connecting bearing 5 and the outer sleeve portion 701 of the pin 7. The inner ring of the connecting bearing 5 and the intermediate force-transmission flange 18 are two separate structures, as are the inner ring of the connecting bearing 5 and the output flange 6. During assembly, the first connecting shaft section 702 of the pin 7 passes through the intermediate force-transmission flange 18. The first shoulder surface 704 of the outer sleeve portion 701 is pressed against the right end face (facing the input flange 2) of the intermediate force-transmission flange 18 via a gasket (or directly), thereby pressing the left side of the intermediate force-transmission flange 18 against the inner ring of the connecting bearing 5. Specifically, mating pressing surfaces are provided on the outer circumferential surface of the intermediate force-transmission flange 18 and the inner bore surface of the inner ring of the connecting bearing 5. Simultaneously, through the screw fastening of the output flange 6 and the first connecting shaft section 702, the output flange 6 is also axially pressed against the left end face of the inner ring of the connecting bearing 5. In this way, the radial dimension of the inner ring of the connecting bearing 5 is small, and the connecting bearing 5 can be selected from conventional models on the market, and its inner ring radial thickness is small, which reduces the manufacturing cost. The other parts of this embodiment are the same as those in the above embodiment 5 and will not be repeated here.

[0088] See also Figure 10 As a preferred design, the swing arm bearing 10 is a cylindrical roller bearing. The planetary gear 8 and the outer ring 101 of the swing arm bearing 10 are an integrated structure. Of course, they can also be two separate structures fixedly connected together. The inner ring 102 of the swing arm bearing 10 and the eccentric part 11 are an integrated structure, and the two are made in one piece. Figure 11 The swing arm bearing 10 can also directly use the eccentric portion 11 as its inner ring, meaning that the eccentric portion 11 also serves as the bearing inner ring 102. The structure and function are not integrated, and the corresponding functional structures of the inner ring can be machined onto the eccentric portion 11. Furthermore, the bearing inner ring 102 and the eccentric portion 11 can be two separate components that are fixedly connected together. With this design, the swing arm bearing 10 effectively prevents the planetary gears 8 from tilting and vibrating when subjected to forces, providing a high load capacity and reliable stability. Furthermore, the axial thickness of the planetary gears 8 is preferably less than the axial thickness of the bearing outer ring 101 of the swing arm bearing 10. This reduces weight and alleviates meshing interference between the planetary gears 8 and the inner gear ring 4. Slight tilt of the planetary gears can mitigate the impact on the meshing transmission between the planetary gears 8 and the inner gear ring 4, making it more suitable for applications requiring high dimensional accuracy, high loads, and high rigidity, such as robotics.

[0089] See also Figure 10The swing arm bearing 10 has cylindrical rollers 103 between its inner ring 102 and outer ring 101. As a preferred design, fixed ribs 104 are provided at both ends of the outer ring 101 to block the cylindrical rollers 103, while the inner ring 102 has a fixed rib 104 at one end and a movable rib 105 at the other end. Alternatively, one end of the outer ring 101 has a fixed rib 104, while the other end has no rib or a movable rib 105. Fixed ribs 104 are provided at both ends of the inner ring 102. The movable ribs 105 are detachable from the inner ring 102 and are fixed to the inner ring 102 when in use. During assembly, the movable rib 105 is removed, and the cylindrical roller 103 is assembled through the position of the movable rib 105, and then the movable rib 105 is reinstalled, which facilitates the on-site assembly of the swing arm bearing 10. In addition, both ends of the bearing outer ring 101 are fixed ribs 104, which can better stabilize the axial position of the planetary gear 8.

[0090] See also Figure 12 and Figure 13 As a preferred design, a spacer 19 is provided between the two planetary gears 8 of the small-tooth differential reducer. The end faces of the spacer 19 on both sides abut against the two planetary gears 8. The inner hole of the spacer 19 is mounted on the pin sleeve 15 or roller bearing 12 on the outside of all the pin shafts 7. The two planetary gears 8 indirectly abut against each other through the spacer 19. The spacer 19 can further stabilize the axial position of the planetary gears 8 and prevent axial shaking between the two planetary gears 8. The spacer 19 can also be omitted between the two planetary gears 8, and the inner sides of the two planetary gears 8 can directly abut against each other. Figure 14 The two planetary gears 8 are each mounted on the eccentric portion 11 via a swing arm bearing 10. The outer rings 101 of the two swing arm bearings 10 may be provided with fixed ribs 104 on both ends for blocking the cylindrical rollers 103. Alternatively, the outer rings 101 may be provided with a fixed rib 104 for blocking the cylindrical rollers 103 on the side facing the other swing arm bearing 10, while not provided with a rib on the other side. The inner ring 102 of the swing arm bearing 10 is provided with a fixed rib 104 for blocking the cylindrical rollers 103 on the side facing away from the other swing arm bearing 10, see Figure 14 In this way, during assembly, the axial clearance of the rollers and the clearance of the bearing outer ring 101 can be adjusted by axially moving the bearing inner ring 102. After the clearance is adjusted, the bearing inner ring 102 and the eccentric part 11 are axially fixed by gluing or welding.

[0091] In summary, the present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0092] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed in the present invention are intended to be covered by the claims of the present invention.

Claims

1. A small-tooth-difference speed reducer, comprising an input flange (2), a load-balancing ring (3), an inner gear ring (4), a connecting bearing (5), a planetary gear (8) and a pin (7), wherein the pin (7) comprises a core shaft portion and an outer shaft sleeve portion (701), wherein the outer shaft sleeve portion (701) is sleeved on the core shaft portion, and the parts of the core shaft portion extending from the outer shaft sleeve portion (701) at both ends are respectively a first connecting shaft section (702) and a second connecting shaft section (703), wherein the outer shaft sleeve portion (701) is fixed to the core shaft portion or can be axially moved relative to the core shaft portion, and the outer shaft sleeve portion ( The end face of the outer sleeve portion (701) facing the first connecting shaft section (702) constitutes a first shoulder face (704), and the first shoulder face (704) is used to directly or indirectly abut and position the inner ring of the connecting bearing (5); the end face of the outer sleeve portion (701) facing the second connecting shaft section (703) is a second shoulder face (705), and the second shoulder face (705) is used to directly or indirectly abut and position the load-balancing ring (3); the pin (7) passes through the planetary gear (8), and the planetary gear (8) is located on the outer sleeve portion (701), and is characterized in that: The first connecting shaft section (702) of the pin shaft (7) is fixedly connected to the inner ring of the connecting bearing (5), and the second connecting shaft section (703) is fixedly connected to the load-balancing ring (3); or, the outer ring of the connecting bearing (5) and the input flange (2) are respectively fixedly connected to the inner gear ring (4), an input flange bearing (9) is provided between the input flange (2) and the load-balancing ring (3), and the input flange (2) applies a pressing force toward the output flange (6) on the outer ring of the input flange bearing (9), and the inner ring of the input flange bearing (9) applies a pressing force toward the output flange (6) on the load-balancing ring (3).

2. The small tooth difference reducer according to claim 1, characterized in that: The outer ring of the connecting bearing (5) and the input flange (2) are respectively fixedly connected to the inner gear ring (4); an input flange bearing (9) is provided between the input flange (2) and the load-balancing ring (3); the input flange (2) applies a pressing force toward the output flange (6) on the outer ring of the input flange bearing (9); and the inner ring of the input flange bearing (9) applies a pressing force toward the output flange (6) on the load-balancing ring (3); a first pressing surface is provided on the inner hole surface of the input flange (2); a second pressing surface is provided on the outer peripheral surface of the outer ring of the input flange bearing (9), and the first pressing surface is pressed against the second pressing surface; a third pressing surface is provided on the inner hole surface of the inner ring of the input flange bearing (9), and a fourth pressing surface is provided on the outer peripheral surface of the load-balancing ring (3), and the third pressing surface is pressed against the fourth pressing surface.

3. The small tooth difference reducer according to claim 1, characterized in that: It also includes an output flange (6), the output flange (6) is fixedly connected to the inner ring of the connecting bearing (5), the first connecting shaft section (702) of the pin shaft (7) is fixedly connected to the inner ring of the connecting bearing (5) or fixedly connected to the output flange (6), and the second connecting shaft section (703) is fixedly connected to the load-balancing ring (3).

4. The small tooth difference reducer according to claim 3, characterized in that: A first pressing nut (13) and a second pressing nut (14) are respectively screwed onto the first connecting shaft section (702) and the second connecting shaft section (703) of the pin shaft (7), wherein the first pressing nut (13) is pressed onto the inner ring of the connecting bearing (5) or the output flange (6), and the second pressing nut (14) is pressed onto the load-balancing ring (3); or, a first screw (16) is screwed onto the end face of the first connecting shaft section (702) of the pin shaft (7), and the nut of the first screw (16) is pressed onto the inner ring of the connecting bearing (5) or the output flange (6), and a second screw (17) is screwed onto the end face of the second connecting shaft section (703) of the pin shaft (7), and the nut of the second screw (17) is pressed onto the load-balancing ring (3).

5. The small tooth difference reducer according to claim 3, characterized in that: The first connecting shaft section (702) of the pin shaft (7) is fixedly connected to the inner ring of the connecting bearing (5) or the output flange (6) by means of threaded connection, welding, adhesive connection or interference fit, and the second connecting shaft section (703) is fixedly connected to the load-balancing ring (3) by means of threaded connection, welding, adhesive connection or interference fit.

6. The small tooth difference reducer according to any one of claims 1 to 5, characterized in that: An intermediate force transmission flange (18) is provided between the inner ring of the connecting bearing (5) and the outer shaft sleeve (701) of the pin shaft (7), and the two ends of the intermediate force transmission flange (18) are respectively in contact with the inner ring of the connecting bearing (5) and the first shaft shoulder surface (704); the first connecting shaft section (702) of the pin shaft (7) passes through the intermediate force transmission flange (18) and is fixedly connected to the output flange (6).

7. The small tooth difference reducer according to claim 1, characterized in that: The invention also includes an input shaft (1) and a swing arm bearing (10), wherein an eccentric portion (11) is fixedly provided on the input shaft (1), and the planetary gear (8) is mounted on the eccentric portion (11) via the swing arm bearing (10), and the swing arm bearing (10) is a cylindrical roller bearing, and the planetary gear (8) is fixedly connected to or integrated with the bearing outer ring (101) of the swing arm bearing (10), and the bearing inner ring (102) of the swing arm bearing (10) is fixedly connected to or integrated with the eccentric portion (11).

8. The small tooth difference reducer according to claim 7, characterized in that: The axial thickness of the planetary gear (8) is smaller than the axial thickness of the bearing outer ring (101) of the swing arm bearing (10).

9. The small tooth difference reducer according to claim 7, characterized in that: A cylindrical roller (103) is provided between the bearing inner ring (102) and the bearing outer ring (101) of the swing arm bearing (10); fixed ribs (104) for blocking the cylindrical roller (103) are provided on both ends of the bearing outer ring (101); one end of the bearing inner ring (102) is provided with a fixed rib (104) for blocking the cylindrical roller (103), and the other end is provided with a movable rib (105) for blocking the cylindrical roller (103); or, one end of the bearing outer ring (101) is provided with a fixed rib (104) for blocking the cylindrical roller (103), and the other end is not provided with a rib or is provided with a movable rib (105) for blocking the cylindrical roller (103), and both ends of the bearing inner ring (102) are provided with fixed ribs (104) for blocking the cylindrical roller (103).

10. The reducer with small tooth difference according to claim 7, characterized in that: A cylindrical roller (103) is provided between the bearing inner ring (102) and the bearing outer ring (101) of the swing arm bearing (10); two planetary gears (8) are mounted on the eccentric portion (11) through each swing arm bearing (10), and the two planetary gears (8) are directly or indirectly in contact with each other; fixed ribs (104) for blocking the cylindrical roller (103) are provided on both ends of the bearing outer ring (101) of the swing arm bearing (10), or the bearing outer ring (101) is provided with a fixed rib (104) for blocking the cylindrical roller (103) on one side facing the other swing arm bearing (10), and no rib is provided on the other side; The bearing inner ring (102) of the swing arm bearing (10) is provided with a fixed rib (104) for blocking the cylindrical roller (103) on the side facing away from the other swing arm bearing (10).

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