A high-load, lightweight micro harmonic reducer

Abstract

The present invention relates to the technical field of reducers, and specifically to a high-load lightweight micro harmonic reducer, comprising a rigid wheel, a flexible wheel, and a wave generator connected to a power input end, wherein the wave generator is mounted in the inner hole of the flexible wheel through a flexible bearing, the flexible bearing is sleeved on the outside of the wave generator and is located between the inner hole of the flexible wheel and the wave generator, the rigid wheel and the flexible wheel are meshed for transmission, the flexible wheel and the rigid wheel are connected through a main load bearing, the main load bearing and the rigid wheel are sealed through a skeleton oil seal, the main load bearing is mounted in the inner hole of the rigid wheel and is threadedly connected to the inner hole of the rigid wheel, the main load bearing is mounted in the rigid wheel by a threaded connection, the rigid wheel is not restricted by the position of the screw holes for mounting the main load bearing, the volume of the rigid wheel also has a large space for reduction, the weight of the rigid wheel is further compressed, and the mass and volume of the entire reducer are further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of speed reducers, and in particular to a high-load-bearing, lightweight micro harmonic speed reducer. Background Art

[0002] A harmonic reducer is a reduction gear mechanism consisting of three key components: a rigid wheel, a flexspline, and a wave generator; a flexible bearing; and a main load bearing. The rigid wheel is a rigid internal gear; the flexspline is a deformable, thin-walled cylindrical external gear; the wave generator is an elliptical disc; and the flexible bearing is an elastically deformable, thin-walled ball bearing. Due to their unique advantages, such as large transmission ratio, high load capacity, high transmission efficiency, small size, light weight, smooth transmission, and high transmission precision, harmonic reducers are widely used in industries such as aerospace, bionic machinery, general military equipment, machine tools, electronic equipment, and robotics. With the continuous advancement of science and technology, the requirements for harmonic reducers are becoming increasingly stringent across various industries, especially for micro harmonic reducers.

[0003] Currently, there are two types of micro harmonic reducers on the market: one using a four-point contact ball bearing as the main load bearing and the other using a cross roller bearing. The micro harmonic reducer using a four-point contact ball bearing as the main load bearing has a very poor ability to withstand axial loads and bending loads due to the characteristics of the bearing itself, often failing to meet the requirements of use and easily being damaged during use. The micro harmonic reducer using a cross roller bearing as the main load bearing is difficult to compress in terms of mass and volume due to the interference of the mounting screw holes. Compared with the micro harmonic reducer of the same size using a four-point contact ball bearing as the main load bearing, the mass and volume are more than 50% higher.

[0004] In response to the above-mentioned technical problems, the present invention proposes a micro harmonic reducer with high load-bearing capacity, light weight, small size, simple manufacturing and convenient installation. Summary of the Invention

[0005] The object of the present invention is to provide a high-load, lightweight micro harmonic reducer, comprising a rigid wheel, a flexible wheel, and a wave generator connected to a power input end, wherein the wave generator is mounted in the inner hole of the flexible wheel through a flexible bearing, the flexible bearing is sleeved on the outside of the wave generator and is located between the inner hole of the flexible wheel and the wave generator, the rigid wheel and the flexible wheel are meshed for transmission, the flexible wheel and the rigid wheel are connected through a main load bearing, the main load bearing and the rigid wheel are sealed through a skeleton oil seal, the main load bearing is mounted in the inner hole of the rigid wheel and is threadedly connected to the inner hole of the rigid wheel, the main load bearing comprises a cross bearing outer ring and a cross bearing inner ring, the cross bearing outer ring is threadedly connected to the inner hole of the rigid wheel, and the cross bearing inner ring is fixedly connected to the flexible wheel.

[0006] Preferably, a negative clearance design is used between the outer ring of the cross bearing and the inner ring of the cross bearing, and the rolling elements therebetween are cylindrical rollers.

[0007] Preferably, the outer ring of the cross bearing is processed with an external thread, and the end of the inner hole of the wheel is processed with an internal thread hole, and the external thread of the outer ring of the cross bearing is threadedly connected with the internal thread hole in the inner hole of the wheel.

[0008] Preferably, a positioning column is provided at the external thread end of the outer ring of the cross bearing, the diameter of the positioning column is smaller than the thread pitch of the external thread, the positioning column is inserted into the inner hole of the rigid wheel through the positioning hole, and the positioning hole is opened at the bottom of the internal thread hole of the rigid wheel. The diameter of the positioning hole is the same as the diameter of the positioning column at the front end of the thread of the outer ring of the cross bearing, and the positioning column and the positioning hole are matched with H6 / h5 tolerance.

[0009] Preferably, an inner roller groove is provided on the inner side of the outer ring of the cross bearing, and an outer roller groove is provided on the outer side of the inner ring of the cross bearing. The cylindrical rollers are arranged in a full cross pattern in the roller groove formed by the inner roller groove and the outer roller groove.

[0010] Preferably, the connection between the inner ring of the cross bearing and the flexible wheel is provided with a cross bearing ball filling block for installing cylindrical rollers. The cross bearing ball filling block is installed on the inner ring of the cross bearing by a first screw. The cross bearing ball filling block and the inner ring of the cross bearing cooperate to form a complete outer roller groove.

[0011] Preferably, the flexible wheel is connected to the inner ring of the cross bearing through an inner pad, the inner pad is installed in the inner hole of the flexible wheel through a second screw, the second screw is installed at the bottom of the flexible wheel cylinder through a screw hole, the screw hole is opened at the bottom of the flexible wheel cylinder, and the inner pad and the flexible wheel are both threadedly connected to the inner ring of the cross bearing through the second screw.

[0012] Preferably, the wave generator is provided with an elliptical portion, the circumference of the elliptical portion is equal to the circumference of the inner hole of the flexible bearing, and the inner ring of the flexible bearing is fixed to the elliptical portion by metal glue.

[0013] Preferably, the inner hole of the rigid wheel is provided with an inner gear ring, and the outer side of the cylinder of the flexible wheel is provided with an outer gear ring. The inner gear ring of the rigid wheel is meshed with the outer gear ring of the flexible wheel, and the number of teeth of the inner gear ring of the rigid wheel is two more than the number of teeth of the outer gear ring of the flexible wheel.

[0014] Preferably, the outer shell of the rigid wheel is made of aluminum, the inner gear ring of the rigid wheel is made of ductile iron, and the outer shell and the inner gear ring are formed into a whole by adopting a steel-aluminum composite process.

[0015] Beneficial effects of the present invention:

[0016] 1. The main load bearing of this product adopts a cross bearing structure. Compared with traditional four-point contact ball bearings, the central rolling element of this bearing is cylindrical roller, and the full complement of rollers is arranged in a cross-shaped pattern, which can effectively ensure the rigidity of the entire product. At the same time, the negative clearance design ensures that the product can withstand bending moments while effectively achieving the accuracy of the entire machine.

[0017] 2. The cross bearing outer ring and the rigid wheel are connected by a direct threaded connection. Since there are no restrictions on the location of the mounting screw holes, the cross bearing has a large space for reduction in size. The cross bearing outer ring is processed with an external thread, and the front end of the thread has a locating column with a diameter slightly smaller than the thread diameter. The end of the rigid wheel inner hole is processed with an internal thread, and the rear end of the thread has a locating hole with a diameter identical to the locating column at the front end of the cross bearing outer ring thread. The locating column and locating hole are matched with an H6 / H5 tolerance to ensure the coaxiality of the cross bearing and rigid wheel after assembly.

[0018] 3. The rigid pulley breaks through the traditional materials and processing technology, adopting the steel-aluminum composite processing and molding technology. The outer shell is made of aluminum to reduce the weight of the rigid pulley, and the inner ring gear is made of ductile iron to ensure the strength and performance of the tooth. At the same time, the rigid pulley is not restricted by the cross bearing mounting screw hole position, and the volume of the rigid pulley can be greatly reduced, which further reduces the weight of the rigid pulley. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0020] Figure 1 It is a cross-sectional schematic diagram of an embodiment of the present invention.

[0021] Figure 2 This is an exploded cross-sectional view of the main load bearing.

[0022] Figure 3 It is a cross-sectional view of the flexible spline and the rigid spline.

[0023] Figure 4 is a cross-sectional view of the wave generator and the flexible bearing.

[0024] Figure 5 It is the front view of the present invention.

[0025] Figure 6 It is a cross-sectional view of the main load bearing.

[0026] Attached mark in the figure:

[0027] 1-wave generator; 1a-elliptical part; 2-flexible bearing; 3-rigid wheel; 3a-internal thread; 3b-inner gear ring; 3c-positioning hole; 4-skeleton oil seal; 5-inner ring of cross bearing; 5a-outer roller groove; 6-cylindrical roller; 7-outer ring of cross bearing; 7a-positioning column; 7b-external thread; 7c-inner roller groove; 8-cross bearing ball filling block; 9-flexible wheel; 9a-screw hole; 9b-outer gear ring; 10-inner spacer; 11-second screw; 12-first screw; 13-main load bearing. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0029] Among them, the drawings are only used for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0030] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inside", "outside" and the like indicate an orientation or position relationship based on the orientation or position relationship shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0031] In the description of the present invention, unless otherwise expressly specified or limited, when the term "connection" or the like appears to indicate a connection relationship between components, such term should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be internal communication between two components or an interaction between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0032] like Figures 1 to 6 As shown, the present invention provides the following embodiments:

[0033] A high-load, lightweight micro harmonic reducer includes a rigid wheel 3, a flexible wheel 9, and a wave generator 1 connected to the power input end. The wave generator 1 is installed in the inner hole of the flexible wheel 9 through a flexible bearing 2. The flexible bearing 2 is sleeved on the outside of the wave generator 1 and is located between the inner hole of the flexible wheel 9 and the wave generator 1. The rigid wheel 3 and the flexible wheel 9 are meshed for transmission. The flexible wheel 9 and the rigid wheel 3 are connected through a main load bearing 13. The main load bearing 13 and the rigid wheel 3 are sealed by a skeleton oil seal 4. The main load bearing 13 is installed in the inner hole of the rigid wheel 3 and is threadedly connected to the inner hole of the rigid wheel 3. The main load bearing 13 includes a cross bearing outer ring 7 and a cross bearing inner ring 5. The cross bearing outer ring 7 is threadedly connected to the inner hole of the rigid wheel 3, and the cross bearing inner ring 5 is fixedly connected to the flexible wheel 9.

[0034] The cross bearing outer ring 7 and the cross bearing inner ring 5 are designed with negative clearance, and the rolling elements between the two are cylindrical rollers 6.

[0035] The outer ring 7 of the cross bearing is processed with an external thread 7b, and the end of the inner hole of the rigid wheel 3 is processed with an internal thread 3a hole. The external thread 7b of the outer ring of the cross bearing 7 is threadedly connected with the internal thread 3a hole in the inner hole of the rigid wheel 3.

[0036] A positioning column 7a is provided at the end of the external thread 7b of the outer ring 7 of the cross bearing. The diameter of the positioning column 7a is smaller than the thread pitch of the external thread 7b. The positioning column 7a is inserted into the inner hole of the rigid wheel 3 through the positioning hole 3c. The positioning hole 3c is opened at the bottom of the internal thread hole of the rigid wheel 3. The diameter of the positioning hole 3c is the same as the diameter of the positioning column 7a at the front end of the thread of the outer ring 7 of the cross bearing. The positioning column 7a and the positioning hole 3c are matched with H6 / h5 tolerance.

[0037] An inner roller groove 7c is provided on the inner side of the cross bearing outer ring 7, and an outer roller groove 5a is provided on the outer side of the cross bearing inner ring 5. The cylindrical rollers 6 are arranged in a full cross pattern in the roller groove formed by the inner roller groove 7c and the outer roller groove 5a.

[0038] A cross bearing ball filling block 8 for mounting the cylindrical roller 6 is provided at the connection between the inner ring 5 of the cross bearing and the flexible spline 9. The cross bearing ball filling block 8 is mounted on the inner ring of the cross bearing by a first screw 12. The cross bearing ball filling block 8 and the inner ring of the cross bearing cooperate to form a complete outer roller groove 5a.

[0039] The flexible wheel 9 is connected to the inner ring 5 of the cross bearing through the inner pad 10. The inner pad 10 is installed in the inner hole of the flexible wheel 9 through the second screw 11. The second screw 11 is installed at the bottom of the cylinder of the flexible wheel 9 through the screw hole 9a. The screw hole 9a is opened at the bottom of the cylinder of the flexible wheel 9. The inner pad 10 and the flexible wheel 9 are both threadedly connected to the inner ring 5 of the cross bearing through the second screw 11.

[0040] The wave generator 1 is provided with an elliptical portion 1a, the circumference of the elliptical portion 1a is equal to the circumference of the inner hole of the flexible bearing 2, and the inner ring of the flexible bearing 2 is fixed to the elliptical portion 1a by metal glue.

[0041] An inner ring gear 3b is provided in the inner hole of the rigid wheel 3, and an outer ring gear 9b is provided on the outer side of the cylindrical body of the flex spline 9. The inner ring gear 3b of the rigid wheel 3 meshes with the outer ring gear 9b of the flex spline 9. The inner ring gear 3b of the rigid wheel 3 has two more teeth than the outer ring gear 9b of the flex spline 9. The outer shell of the rigid wheel 3 is made of aluminum, and the inner ring gear 3b of the rigid wheel 3 is made of ductile iron. The outer shell and the inner ring gear are made of steel and aluminum composite technology to form a whole.

[0042] Working principle:

[0043] The inner hole of the rigid wheel 3 is processed with an internal thread 3a, and the outer ring 7 of the cross bearing is processed with an external thread 7b. The rigid wheel 3 and the outer ring 7 of the cross bearing are connected through the internal thread 3a and the external thread 7b; the bottom of the flexible wheel 9 is processed with a screw hole 9a, and the end face of the inner ring 5 of the cross bearing is processed with a threaded hole. The flexible wheel 9 and the inner pad 10 and the inner ring 5 of the cross bearing are connected by a second screw 11; the elliptical circumference of the elliptical part 1a of the wave generator 1 is equal to the circumference of the inner hole of the flexible bearing 2, and the flexible bearing The inner ring of 2 is fixed to the cam with metal glue, and the outer ring can be elastically deformed by the ball bearing; after the flexible bearing 2 is pressed onto the outer periphery of the elliptical portion 1a of the wave generator 1, the flexible bearing 2 is forced to be elliptical. After this component is installed into the inner hole of the flexible wheel 9, the flexible wheel 9 is also bent into an elliptical shape by the wave generator 1. Therefore, the outer ring gear 9b of the flexible wheel 9 and the inner ring gear 3b of the rigid wheel 3 are engaged in the long axis part, and in the short axis part, the outer ring gear 9b of the flexible wheel 9 and the inner ring gear 3b of the rigid wheel 3 are completely disengaged.

[0044] When the reducer is operating, the rigid pulley 3 is fixed to the housing, the load is connected to the inner ring 5 of the cross bearing, and the motor input shaft is fixedly connected to the wave generator 1. The motor drives the wave generator 1 to rotate, forcing the flexspline 9 to undergo alternating elastic deformation, and the meshing position of the flexspline 9 teeth and the teeth of the rigid pulley 3 moves sequentially. After the wave generator 1 rotates one revolution, the meshing position of the outer ring gear 9b of the flexspline 9 and the inner ring gear 3b of the rigid pulley 3 also moves one revolution synchronously. Because the flexspline 9 has two fewer teeth than the rigid pulley 3, the flexspline 9 moves two teeth in the opposite direction of the wave generator 1's rotation. As the wave generator 1 rotates continuously with the motor, this action repeats in a cycle, causing the flexspline 9 to slowly rotate relative to the rigid pulley 3 in the opposite direction of the wave generator 1, thereby driving the load to operate synchronously through the inner ring 5 of the cross bearing.

[0045] It should be noted that the above-described specific embodiments are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that various modifications, equivalent substitutions, and variations may be made to the present invention. However, as long as these modifications do not depart from the spirit of the present invention, they are intended to be within the scope of protection of the present invention. Furthermore, certain terms used in the specification and claims of this application are not intended to be limiting and are provided solely for ease of description.

Claims

1. A high-load, lightweight micro harmonic reducer, characterized in that: The invention comprises a rigid wheel (3), a flexible wheel (9) and a wave generator (1) connected to a power input end, wherein the wave generator (1) is installed in the inner hole of the flexible wheel (9) through a flexible bearing (2), the flexible bearing (2) is sleeved on the outer side of the wave generator (1) and is located between the inner hole of the flexible wheel (9) and the wave generator (1), the rigid wheel (3) and the flexible wheel (9) are meshed and driven, the flexible wheel (9) and the rigid wheel (3) are connected through a main load bearing (13), the main load bearing (13) and the rigid wheel (3) are sealed through a skeleton oil seal (4), the main load bearing (13) is installed in the inner hole of the rigid wheel (3) and is threadedly connected to the inner hole of the rigid wheel (3), the main load bearing (13) comprises a cross bearing outer ring (7) and a cross bearing inner ring (5), the cross bearing outer ring (7) is threadedly connected to the inner hole of the rigid wheel (3), and the cross bearing inner ring (5) is fixedly connected to the flexible wheel (9); The outer ring (7) of the cross bearing is processed with an external thread (7b), and the end of the inner hole of the rigid wheel (3) is processed with an internal thread (3a) hole, and the external thread (7b) of the outer ring (7) of the cross bearing is threadedly connected with the internal thread (3a) hole in the inner hole of the rigid wheel (3); A positioning column (7a) is provided at the end of the external thread (7b) of the cross bearing outer ring (7). The diameter of the positioning column (7a) is smaller than the thread pitch of the external thread (7b). The positioning column (7a) is inserted into the inner hole of the rigid wheel (3) through the positioning hole (3c). The positioning hole (3c) is provided at the bottom of the internal thread hole of the rigid wheel (3). The diameter of the positioning hole (3c) is the same as the diameter of the positioning column (7a) at the front end of the thread of the cross bearing outer ring (7). The positioning column (7a) and the positioning hole (3c) are matched with an H6 / h5 tolerance. The flexible wheel (9) is connected to the inner ring (5) of the cross bearing through an inner pad (10), the inner pad (10) is installed in the inner hole of the flexible wheel (9) through a second screw (11), the second screw (11) is installed at the bottom of the flexible wheel (9) cylinder through a screw hole (9a), the screw hole (9a) is opened at the bottom of the flexible wheel (9) cylinder, and the inner pad (10) and the flexible wheel (9) are both threadedly connected to the inner ring (5) of the cross bearing through the second screw (11).

2. A high-load-bearing, lightweight micro harmonic reducer according to claim 1, characterized in that: A negative clearance design is adopted between the cross bearing outer ring (7) and the cross bearing inner ring (5), and the rolling elements therebetween are cylindrical rollers (6).

3. A high-load-bearing, lightweight micro harmonic reducer according to claim 1 or 2, characterized in that: An inner roller groove (7c) is provided on the inner side of the cross bearing outer ring (7), an outer roller groove (5a) is provided on the outer side of the cross bearing inner ring (5), and the cylindrical rollers (6) are arranged in a full cross pattern in a roller groove formed by the inner roller groove (7c) and the outer roller groove (5a).

4. A high-load-bearing, lightweight micro harmonic reducer according to claim 2, characterized in that: A cross bearing ball filling block (8) for mounting a cylindrical roller (6) is provided at the connection portion between the cross bearing inner ring (5) and the flexible wheel (9). The cross bearing ball filling block (8) is mounted on the cross bearing inner ring via a first screw (12). The cross bearing ball filling block (8) and the cross bearing inner ring cooperate to form a complete outer roller groove (5a).

5. The high-load-bearing, lightweight micro harmonic reducer according to claim 1, characterized in that: The wave generator (1) is provided with an elliptical portion (1a), the elliptical circumference of the elliptical portion (1a) is equal to the circumference of the inner hole of the flexible bearing (2), and the inner ring of the flexible bearing (2) is fixed to the elliptical portion (1a) by metal glue.

6. A high-load-bearing, lightweight micro harmonic reducer according to claim 1, characterized in that: The inner hole of the rigid wheel (3) is provided with an inner gear ring (3b), and the outer side of the cylindrical body of the flexible wheel (9) is provided with an outer gear ring (9b). The inner gear ring (3b) of the rigid wheel (3) is meshed with the outer gear ring (9b) of the flexible wheel (9), and the number of teeth of the inner gear ring (3b) of the rigid wheel (3) is two more than the number of teeth of the outer gear ring (9b) of the flexible wheel (9).

7. A high-load-bearing, lightweight micro harmonic reducer according to claim 1, characterized in that: The outer shell of the rigid wheel (3) is made of aluminum material, and the inner gear ring (3b) of the rigid wheel (3) is made of ductile iron. The outer shell and the inner gear ring are formed into a whole by using a steel-aluminum composite process.

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