A self-balancing low-tooth-difference transmission

Abstract

This utility model is a self-balancing gearbox with small tooth difference, which includes at least two axial revolving gears and an eccentric counterweight. The number of teeth of the axial revolving gears B is different, resulting in different centrifugal forces. By adding a matching eccentric counterweight T to the existing structure, and providing specific gearbox structural requirements and installation methods, a more compact structure and smoother operation are achieved.

Description

Technical Field

[0001] This utility model patent relates to a transmission device for a gearbox with a small tooth difference, and belongs to the field of mechanical technology. Background Technology

[0002] In practical use, we found that existing multi-gear transmissions with small tooth difference have an unbalanced angular momentum distribution in the axial direction, which causes the transmission to generate an axial overturning moment during operation, resulting in vibration of the entire transmission. This vibration is particularly noticeable during startup or low-speed operation.

[0003] This is a common problem in all known low-tooth-difference transmissions except for harmonic reducers. In order to solve the above problems scientifically and accurately, this utility model patent is hereby disclosed. Summary of the Invention

[0004] A self-balancing gearbox with small tooth difference includes at least two axially rotating gears and at least one eccentric counterweight. The axially rotating gears have unequal numbers of teeth and are axially offset. Radial and axial balance is achieved through the mounting structure of the eccentric counterweight and the axially rotating gears. Its structural feature is that, in a axial plane coordinate system, with the input shaft's axis as the x-axis and the left end of the input shaft of all eccentric moving parts as the origin, all eccentric parts are distributed at 180° angles on the upper and lower sides of the x-axis. All eccentric parts on both sides then share a common equilibrium point on the x-axis. The formula for the position p of the equilibrium point p of all eccentric parts on the same side on the x-axis is:

[0005]

[0006] Where x is the x-coordinate distance between the center of mass of all eccentric parts and the origin of the x-axis, and W is the mass-radius product of each eccentric part, which is the mass multiplied by the eccentricity. The mass-radius products on both sides of the x-axis are equal.

[0007] Each eccentrically moving component, including the central rotating gear, the bearing mounted on the central rotating gear, the eccentric bushing, and the eccentric counterweight, generates centrifugal force when revolving around the input shaft. Each centrifugal force acts at a different position on the input shaft. The first objective of this utility model patent is to balance these centrifugal forces. Centrifugal force F c The basic calculation formula is:

[0008] F c =m·e·ω 2

[0009] Where m is the mass, e is the eccentricity, which is the straight-line distance between the center of mass of the part and the center of revolution, and ω is the angular velocity of rotation. Since all parts revolve around the input axis with the same angular velocity, the angular velocity will no longer be considered in the following calculations, and will be replaced by the mass-radius product, i.e., mass multiplied by eccentricity.

[0010] The input shaft is placed horizontally, and its length is set to 1. In the axis-plane coordinate system, the axis center is taken as the x-axis, the left end of the input shaft is taken as the origin (x = 0), and the right end is taken as x = 1. There are n eccentric parts distributed at 180° intervals on the upper and lower sides of the x-axis. When the revolution speed of all eccentric moving parts is the same, their centrifugal forces are also fixed. From the above structure, it is clear that parts with their centers of mass at the top and bottom of the x-axis can each find an equilibrium point on the x-axis. An equilibrium point is defined as a point where the torques on both sides are equal. Taking the eccentric part with its center of mass at the top of the x-axis as an example, the centrifugal force of the upper eccentric part is upward, and it can find an equilibrium point on the x-axis where the upward torques on both sides are equal. Similarly, the part with its center of mass at the bottom of the x-axis can also find an equilibrium point. Let the equilibrium point be at position x = p, and n eccentric moving parts are distributed on both sides of point p. Measured from the left, the mass-radius product of the i-th eccentric moving part is W. i The torque applied about the equilibrium point to the eccentrically moving part i is as follows:

[0011] M i =W i ×(x i -p)

[0012] Equilibrium condition:

[0013]

[0014] Solving the equation, we get:

[0015]

[0016] The above calculations yielded the positions of the equilibrium points on both the upper and lower sides of the x-axis. Clearly, when the equilibrium points on both sides are at the same position on the x-axis, and the mass-radius product ∑W on both sides is... i When the speeds are equal, the entire transmission is balanced and will not vibrate regardless of the engine speed.

[0017] The second objective of this utility model patent is to provide a small-sized and high-torque transmission based on a self-balancing design. This transmission includes at least four gears: gears A1 and A2 are fixed-axis gears, and gears B1 and B2 are axial-revolving gears. An eccentric component drives the axial-revolving gears to mesh with the fixed-axis gears. Gear A1 meshes with gear B1, and gear A2 meshes with gear B2. Gear B1 has N teeth, gear A1 has N+Q teeth, gear B2 has N+M teeth, and gear A2 has N+M+Q teeth, where M≥1 and Q=1. Alternatively, Q = 2; the gear combination methods include one of the following: The first method is a fixed-axis gear connection, where one of the central rotating gears can be fixed and does not rotate, while the unfixed central rotating gear can drive the output shaft; the second method is a synchronous fixing of the central rotating gears in the direction of rotation, where one of the fixed-axis gears can be fixed and does not rotate, while the unfixed fixed-axis gear can drive the output shaft; the third method is a fixed-axis gear connection, where one of the fixed-axis gears can be fixed, while the unfixed fixed-axis gear can drive the output shaft.

[0018] The purpose of the above design is to achieve a large reduction ratio within a relatively small space. The reduction ratio is at its maximum when M = Q = 1. Due to the large reduction ratio, the reverse drive resistance is also large, especially when N is greater than 20, in which case reverse drive may experience self-locking. When reverse drive is required, the reduction ratio can be reduced by increasing the value of M, thereby reducing the reverse drive resistance.

[0019] As an effective improvement of this utility model patent, the eccentric counterweight can be adjusted and positioned in the axial position during installation to accommodate the different angular momentum of different batches of shaft-centric revolution gears caused by installation errors. Alternatively, the eccentric counterweight and all other eccentric moving parts and input shaft can be corrected on a dynamic balancing machine as a whole before use. The correction methods include, but are not limited to, adjusting the mass of the eccentric counterweight or adjusting the axial position of the eccentric counterweight, having one or a combination of the above two features.

[0020] The purpose of the above design is to allow the eccentric counterweight to be adjusted and positioned axially during installation, which can speed up the assembly of the transmission and save time. The eccentric counterweight and all other eccentric moving parts are treated as a whole and corrected on the dynamic balancing machine. This means that after all the eccentric moving parts are assembled onto the input shaft, they are treated as a whole and then corrected on the dynamic balancing machine.

[0021] As an alternative, at least two more gears can be added to the four gears: a fixed-axis gear A3 and a central rotating gear B3. The central rotating gear B3 is driven by an eccentric shaft to mesh with the fixed-axis gear A3. The number of teeth of the central rotating gear B3 is N+P, and the number of teeth of the fixed-axis gear A3 is N+P+Q, where P≥1, Q=1 or Q=2; or multiple sets of gears can be added according to this structure.

[0022] The purpose of the above design is to increase the number of reduction ratios and provide more options for reverse drive of the transmission.

[0023] As an alternative to the gear design in this utility model patent, the gear of the transmission may include a pin gear, which includes a pin gear housing and pin teeth. The pin gear housing contains tooth grooves, and the pin teeth are rolling bodies that can roll along the tooth surface of the tooth grooves of the pin gear housing. The transmission also includes a device to prevent the pin teeth from falling out of the tooth grooves of the pin gear. The device to prevent the pin teeth from falling out may be, but is not limited to, one or a combination of more than one of the following: baffle, flange, and annular barrier.

[0024] The advantages of the above design are that the needle teeth can use solid rolling elements, reducing the difficulty of machining, and all contact surfaces are rolling contacts, thus resulting in higher torque output capability.

[0025] The third objective of this utility model patent is to provide an active cooling transmission, which is achieved by: the transmission including a structure that can force the surrounding fluid to flow, or the transmission including centrifugal blades, or the transmission housing having heat dissipation fins, or a portion of the transmission housing being made of aluminum or copper, or the transmission housing having aluminum or copper heat dissipation fins, or the ends of the eccentric counterweight in the transmission being streamlined, or the transmission including centrifugal blades driven by the input shaft, or the transmission including a flow guiding structure that directs the flow of fluid, having one or a combination of the above structures.

[0026] The purpose of this design is to enable the transmission to actively dissipate heat, thereby increasing the continuous use time and service life of the workpiece. The streamlined design of the two ends of the eccentric counterweight in the transmission reduces resistance and the change in angular momentum caused by resistance.

[0027] The design scheme of the tooth profile curve of the tooth groove or the tooth profile curve of the gear in this utility model patent includes the following schemes: at least one tooth profile curve includes a circular arc curve, or at least one tooth profile curve includes a cycloid, or at least one tooth profile curve includes an elliptical curve, or at least one tooth profile curve includes an elliptical cycloid, or at least one tooth profile curve includes a straight line, or at least one tooth profile curve includes an involute, or at least one tooth profile curve includes a conical curve, or includes a helical gear, or includes a pair of helical gears with opposite helical directions; including one or a combination of the above schemes.

[0028] As an alternative to this utility model patent, the transmission also includes a clutch C, the installation structure of which includes, but is not limited to: the first type is that the rotation of one gear is fixed by switching the clutch C, and the output is provided by the other gear; the second type of installation structure is that the output gear ratio can be switched according to external load or machine command, including one of the above two clutch installation structures, or a combination of the two structures.

[0029] The purpose of the above design is to provide multiple gears in a single transmission. When there are only two pivoting gears and M = Q = 1, two gears with a multiplicative relationship and the same direction can be achieved, i.e., n. 2 The gear ratios are either n:1 or n:1, or [n×(n+2)]:1 or n:1. Of course, more gears are possible with more rotating shafts. A significant advantage is its applicability to scenarios with constantly changing loads, such as the joints of reciprocating transport machinery, the joints of heavy-duty running machinery, or vehicles that need to travel on various road conditions.

[0030] This utility model patent describes a self-balancing low-tooth-difference transmission that can be used with various engines to form a power output module. The engine may include, but is not limited to, an axial flux motor, an external rotor motor, an internal rotor motor, or a turbine.

[0031] This utility model patent discloses a self-balancing low-tooth-difference transmission, which can be applied in transmission systems. Its application scenarios include, but are not limited to, propeller-driven, hub-driven, or mechanical actuators. The mechanical actuators can be applied to, but are not limited to, rotary joints of industrial machinery, wearable robotic arms, reciprocating transport machines, embodied intelligent machines, vehicle steering systems, aircraft steering rudder transmission systems, ship steering rudder transmission systems, or the transmission can be applied to electric vehicles or electric engineering machinery.

[0032] The technical advantages and scope of protection of this utility model patent will become clearer with reference to the accompanying drawings. The drawings and their descriptions are for illustrative purposes only and do not limit the scope of protection of this utility model patent. Attached Figure Description

[0033] Symbol explanations in the diagram: A1 – Fixed-axis gear No. 1; A11 – Needle tooth in the pin gear; A2 – Fixed-axis gear No. 2; A3 – Fixed-axis gear No. 3; B1 – Rotating gear of shaft No. 1; B2 – Rotating gear of shaft No. 2; B12 – Pin; B121 – Pin disc; B221 – Annular stop No. 1; B222 – Annular stop No. 2; B3 – Rotating gear of shaft No. 3; C1 – Clutch No. 1; C2 – Clutch No. 2; D1 – Fixed disc connecting the outer casing; D21 – First outer casing connection part; D22 – Second outer casing connection part; D3 – Heat dissipation fins D4 – Centrifugal blade; E1 – Eccentric shaft No. 1; E2 – Eccentric shaft No. 2; Input shaft – G1; Output shaft – G2; F – Rolling element; O – Shaft center position; H1 – Motor stator; H2 – Motor rotor; K – Bushing; M – Center of mass; P – Balance point position; T1 – Eccentric counterweight No. 1; T2 – Eccentric counterweight No. 2; T3 – Eccentric counterweight No. 3; T11 – Eccentric counterweight body; T12 – Eccentric counterweight retaining ring; T13 – Spring plate; T21 – Eccentric counterweight connector; T22 – Positioning nut.

[0034] Figure 1 This is a diagram illustrating the relationship between the equilibrium point and each eccentrically moving part.

[0035] Figure 2 This is a schematic diagram of the axial cross-section of a transmission with two rotating gears fixed together on two shafts.

[0036] Figure 3 This is a schematic diagram of the installation structure of the eccentric counterweight parts.

[0037] Figure 4 This is a schematic diagram of the axial cross-section of a transmission with three rotating gears fixed together on a central axis.

[0038] Figure 5 This is a schematic diagram of the axial cross-section of a power output module that combines a self-balancing transmission and an electric motor. Detailed Implementation

[0039] The advantages and preferred embodiments of this utility model patent are illustrated with reference to the accompanying drawings. Specific examples are provided to illustrate the advantages of this utility model patent and should not be construed as limiting the scope of protection of this utility model patent.

[0040] Figure 1This diagram illustrates the relationship between the equilibrium point and each eccentrically moving component. The XY coordinate system in the diagram represents the plane coordinates of the transmission shaft. The X-axis is the centerline of the transmission input shaft, and the origin O is the leftmost end of the input shaft. The center of mass of the planetary gear B1 (shaft 1) is M1, the eccentricity of M1 is y2, and the distance from M1 to the origin on the X-axis is x1. The center of mass of the planetary gear B2 (shaft 2) is M2, the eccentricity of M2 is y3, and the distance from M2 to the origin on the X-axis is x2. The center of mass of the planetary gear B3 (shaft 3) is M3, the eccentricity of M3 is y1, and the distance from M3 to the origin on the X-axis is x3. The center of mass of the eccentric counterweight T1 is M4, the eccentricity of M4 is y4, and the distance from M4 to the origin on the X-axis is x4. As shown in the figure, the centers of mass of the No. 1 and No. 3 axis revolving gears are above the X-axis. According to the formula for the equilibrium point p disclosed in this utility model patent, we know that:

[0041]

[0042] All of these parameters are known when designing the transmission, so the position of p can be directly determined.

[0043] Furthermore, based on the indication in this utility model patent that the mass-radius products on both the upper and lower sides of the X-axis are equal, it can be inferred that:

[0044] M1×y2+M3×y1=M2×y3+M4×y4

[0045] Therefore, the mass-radius product M4×y4 of the eccentric counterweight T1 can be directly obtained. According to the disclosure in this utility model patent that the upper and lower sides of the X-axis have a common equilibrium point, it can be known that:

[0046]

[0047]

[0048] Therefore, the coordinate x4 of the eccentric counterweight part T1 on the X-axis can be directly obtained.

[0049] Since the mass-diameter product M4×y4 of the eccentric counterweight T1 is known, the eccentricity y4 of the eccentric counterweight T1 can be obtained according to the diameter space of the transmission and the design requirements. Based on this, the required mass of the eccentric counterweight T1 can be obtained, and the required materials, shape, etc. can be designed according to the required mass.

[0050] The above is a demonstration of the application of the self-balancing structure in this utility model patent. The number of the axial revolving gear and the eccentric counterweight can be more or less. The center of mass can be the center of mass of various eccentrically moving parts, including but not limited to eccentric counterweight, axial revolving gear, eccentrically moving bearing, eccentric shaft, grease in the eccentrically moving bearing, eccentrically moving bushing, etc. The self-balancing design principle is the same as the above demonstration.

[0051] Figure 2 This is an axial cross-sectional schematic diagram of a transmission with two fixed-axis rotating gears. The two rotating gears used in this example are a pair of helical gears with opposite inclination directions, and rotating gear B1 and rotating gear B2 are coaxially fixed together. Figure 2 The middle part is the input shaft G1, whose axis is O2. The input shaft G1 is connected to the fixed plate D1 of the connecting shell through the No. 1 rolling element F1. The fixed plate D1 of the connecting shell is also fixed to the first shell connecting part D21, which has heat dissipation fins D3.

[0052] Figure 2 The right side of the first housing connecting part D21 is fixedly connected to the second fixed-axis gear A2. The second fixed-axis gear A2 is connected to the first fixed-axis gear A1 through the fourth rolling element F4. The right side of the first fixed-axis gear A1 is fixedly connected to the second housing connecting part D22, which also has heat dissipation fins D3. The second housing connecting part D22 is fixedly connected to the output shaft G2, which is connected to the input shaft G1 through the fifth rolling element F5.

[0053] Figure 2 The input shaft G1 also has an eccentric shaft E1, the outer circle of which is centered at O1. Eccentric shaft E1 is connected to the planetary gears B1 and B2 via rolling elements F2 and F3. The input shaft G1 also has centrifugal blades D4, which rotate with the input shaft G1 and use centrifugal force to drive the flow of surrounding air or lubricant. Figure 2 As can be seen, after the fluid leaves the outer edge of the centrifugal blade D4, it encounters the ramp on the first outer shell connection part D21. Therefore, the fluid is guided to the meshing part between the second fixed-axis gear A2 and the second axial revolving gear B2. The fluid continues to the right, passing through the meshing part between the first fixed-axis gear A1 and the first axial revolving gear B1, and only after reaching the second outer shell connection part D22 can it flow back to the centrifugal blade D4 through the gap between the third rolling element F3 and the second rolling element F2. The outer layers of the first outer shell connection part D21 and the second outer shell connection part D22 have heat dissipation fins D3 to cool the fluid. Therefore, all friction surfaces have fluid passing through and being cooled at appropriate locations. The first outer shell connection part D21, the second outer shell connection part D22, and the heat dissipation fins D3 can all be made of aluminum alloy or copper alloy, which improves the heat dissipation efficiency.

[0054] Figure 2 The input shaft G1 also has eccentric counterweights T1 and T2. As shown in the diagram, the centers of mass of the following components are all near position O1 on the upper part of the input shaft center O2: the planetary gear B1 (center 1), the planetary gear B2 (center 2), the eccentric shaft E1, the rolling element F2, and the rolling element F3. Their eccentricities are relatively close. Conversely, the centers of mass of eccentric counterweights T1 and T2 are located below and far from the input shaft center O2, resulting in a greater eccentricity. Figure 2 The measured results in this case show that the eccentricity difference between the two is 18 times. Since one of the balance conditions disclosed in this utility model patent is that the mass-radius product on the upper and lower sides of the input shaft is equal, the weight of the eccentric counterweight in this case only needs to be equal to the weight of the other eccentric moving parts. Compared to the traditional low-tooth-difference transmission, which mounts two rotating gears with equal numbers of teeth at 180° and uses pins, pin discs, or cross raceways to control the rotation of the rotating gears, the eccentric counterweight is much lighter than the pins, pin discs, or cross raceways. As a result, the transmission has a higher torque-to-weight ratio, is more stable at low speeds, and has a simpler structure.

[0055] Figure 2 The four gears are two pairs of helical gears with opposite inclination directions, and their tooth profiles can be corrected using involute curves. Let the number of teeth on the first-axis revolving gear B1 be 74, the number of teeth on the first-axis fixed gear A1 be 76, the number of teeth on the second-axis revolving gear B2 be 93, and the number of teeth on the second-axis fixed gear A2 be 95. When the input shaft G1 rotates clockwise one revolution, because the second-axis fixed gear A2 is fixed, the second-axis revolving gear B2 is forced to rotate counterclockwise 2 / 93 revolutions. The first-axis revolving gear B1, which is fixed to it, also rotates counterclockwise 2 / 93 revolutions. Simultaneously, the first-axis revolving gear B1 is also meshing clockwise with the first-axis fixed gear A1. Therefore, the first-axis fixed gear A1 drives the output shaft G2 to rotate 1 / 186 revolutions, resulting in a reduction ratio of 186:1. Thus, according to the technology disclosed in this utility model patent, a large reduction ratio and a high torque-to-weight ratio can be achieved with fewer parts and in a smaller space.

[0056] Figure 3This is a schematic diagram of the eccentric counterweight assembly structure. In the center of the diagram is the input shaft G1. Eccentric shaft E1 (number 1) is mounted on the outer layer of input shaft G1. To the right of eccentric shaft E1 is spring plate T13. To the right of spring plate T13 is eccentric counterweight fixing ring T12. Eccentric counterweight fixing ring T12 is fixed to eccentric counterweight body T11 via eccentric counterweight connector T21. To the right of eccentric counterweight fixing ring T12 is positioning nut T22. As shown in the diagram, positioning nut T22 and spring plate T13 clamp eccentric counterweight fixing ring T12 in the middle. The axial position of eccentric counterweight body can be adjusted by adjusting positioning nut T22. This design facilitates dynamic balancing correction. The diagram also shows that the two ends of eccentric counterweight body T11 are pointed, designed to reduce motion resistance and facilitate accurate dynamic balancing correction.

[0057] Figure 4 This is a schematic diagram of the axial cross-section of a transmission with three rotating gears fixed together on a central axis. Figure 4 Is Figure 2 Based on the case, a pair of gears were added, and... Figure 2 The cases are different, Figure 4 The gears used are pin gears and cycloidal gears with a 1-tooth difference. The input shaft G1 is in the middle of the figure, with its axis at O2. The input shaft G1 is mounted on the fixed disk D1 connecting the housing via rolling element F1. The fixed disk D1 connecting the housing has clutch C1, which can be fixed to either fixed shaft gear A2 or fixed shaft gear A3. The fixed shaft gear contains pin teeth A11, and pin teeth A11 has annular guards B221 and B222 at both ends. Both annular guards at both ends are fixed to the fixed shaft gear.

[0058] Figure 4 An eccentric shaft E1 is fixedly connected to the middle of the input shaft G1. A bushing K is mounted on the eccentric shaft E1 via rolling elements F2 (2) and F3 (3). The shaft center of bushing K is O1. The outer layer of bushing K is fixedly connected to shaft-centric revolving gears B3, B2, and B1. Shaft-centric revolving gear B3 meshes with fixed-axis gear A3 via pin teeth A11; shaft-centric revolving gear B2 meshes with fixed-axis gear A2; and shaft-centric revolving gear B1 meshes with fixed-axis gear A1. The output shaft G2 is connected to the input shaft G1 via rolling element F5 (5). The output shaft G2 is fixedly connected to the first housing connection part D21. The first housing connection part D21 is connected to the fixed disk D1 connecting the housing via rolling element F4 (4).

[0059] Figure 4 Centrifugal blades D4 are mounted on the input shaft G1, and... Figure 2Similar to the previous configuration, centrifugal blade D4 provides active cooling for the transmission. The input shaft G1 is also equipped with eccentric counterweights T1 (number 1), T2 (number 2), and T3 (number 3), which, along with... Figure 2 Similar to the case, the function of the eccentric counterweight is to counteract the centrifugal force of the rotating gear on the shaft, ensuring the smooth operation of the transmission.

[0060] Figure 4 The first housing connection part D21 contains a second clutch C2, which can be fixedly connected to either the second fixed-axis gear A2 or the first fixed-axis gear A1. When the first clutch C1 is fixedly connected to the second fixed-axis gear A2, the second clutch C2 is connected to the first fixed-axis gear A1, and the output is from the first fixed-axis gear A1. When the first clutch C1 is fixedly connected to the third fixed-axis gear A3, the second clutch C2 can either be fixedly connected to the second fixed-axis gear A2 for output, or the second clutch C2 can be fixedly connected to the first fixed-axis gear A1 for output. Those skilled in the art can design appropriate gear teeth and gear positions as needed. Typically, n... 2 There are three gears between n:1 and n:1; when clutch C1 is fixed to fixed shaft gear A2, clutch C2 can also be connected to fixed shaft gear A2 to disconnect the input shaft brake. The above design can adapt to different working conditions, such as switching between no-load and heavy-load, high-speed and low-speed, etc.

[0061] Figure 5 This is an axial cross-sectional diagram of a power output module combining a self-balancing transmission and an electric motor. The input shaft G1 is in the center, with its axis at O2. The input shaft G1 is mounted on the motor housing D1 via rolling elements F1 (1) and F2 (2). The motor also includes a stator H1 and a rotor H2, with the rotor H2 driving the input shaft G1 to rotate. A pin disk B121 is mounted on the input shaft G1 via rolling element F3 (3). Pin disk B121 has a pin B12. A fixed-axis gear A2 is mounted on the outer side of pin disk B121 via rolling element F4 (4). The motor housing D1 also houses a clutch C1, which can connect to the outer fixed-axis gear A2 or the inner pin disk B121. In the diagram, clutch C1 is connected to fixed-axis gear A2, so gear A2 is fixed and does not rotate, while pin disk B121 can rotate.

[0062] Figure 5 The input shaft G1 is also equipped with a second eccentric shaft E2, and the second eccentric shaft E2 is mounted on a second axial planetary gear B2 via a fifth rolling element F5, the axis of which is O1. The second axial planetary gear B2 meshes with the pin tooth A11 on the second fixed shaft gear A2. Figure 5Below the No. 2 fixed-axis gear A2, the No. 1 fixed-axis gear A1 is connected via the No. 6 rolling element F6. The No. 1 fixed-axis gear A1 is connected to the input shaft G1 via the No. 8 rolling element F8, and the No. 1 fixed-axis gear A1 is fixedly connected to the output shaft G2. The input shaft G1 also houses the No. 1 eccentric shaft E1, which is connected to the No. 1 axial planetary gear B1 via the No. 7 rolling element F7. The axis of the No. 1 axial planetary gear B1 is O3. The No. 1 axial planetary gear B1 meshes with the No. 1 fixed-axis gear A1 via the pin tooth A11.

[0063] Figure 5 As can be seen, pin B12 passes through both the No. 2 and No. 1 rotating gears, with the upper portion passing through the No. 2 rotating gear having a larger diameter. The first benefit of this design is that the different diameters of the holes through which pin B12 passes between the No. 1 and No. 2 rotating gears allow for weight adjustment of the two gears and reduces the difference in angular momentum. The second benefit is the creation of a step or ramp between the pin and the gears to withstand axial thrust. Therefore, the entire transmission can withstand bidirectional axial inertial forces or vibrations, and its simple, compact structure allows for the use of either angular contact bearings or tapered bearings for each bearing.

[0064] Figure 5 An eccentric counterweight T1 is also installed on the upper part of the input shaft G1. As shown in the figure, the center of mass of the first-axis planetary gear B1 and the eccentric counterweight T1 is on the right side of the input shaft, while the center of mass of the second-axis planetary gear B2 is on the left side of the input shaft. Since the mass difference between the first-axis planetary gear B1 and the second-axis planetary gear B2 is small, according to the calculation formula published in this utility model patent, a common balance point is needed on both sides of the input shaft, and the eccentric counterweight T1 needs to be far away from the second-axis planetary gear B2. Figure 5 In the case, the mass difference between the first-axis planetary gear B1 and the second-axis planetary gear B2 is approximately... The eccentricity of the eccentric counterweight T1 is approximately 19 times that of the eccentricity of the central axis gear. Therefore, the mass of the eccentric counterweight only needs to be approximately [a fraction of] the mass of the second central axis gear B2. The distance between the eccentric counterweight T1 and the No. 2 shaft planetary gear B2 is about 6 times the distance between the No. 1 shaft planetary gear B1 and the No. 2 shaft planetary gear. Therefore, the eccentric counterweight T1 is installed at the tail of the motor and is relatively light in weight.

[0065] The above examples are provided to more clearly illustrate the advantages of this utility model patent. Based on the structure of the self-balancing low-tooth-difference transmission disclosed in this utility model patent, other specific examples can also be designed. The self-balancing low-tooth-difference transmission disclosed in this utility model patent can be applied in transmission systems. Its application scenarios include, but are not limited to, applications in propeller drives, hub drives, or mechanical actuators. Among them, mechanical actuators can be applied in, but are not limited to, rotary joints of industrial machinery, wearable robotic arms, reciprocating transport machines, embodied intelligent machines, vehicle steering systems, aircraft steering rudder transmission systems, ship steering rudder transmission systems, or the transmission can be applied in electric vehicles or electric engineering machinery, and so on.

Claims

1. A self-balancing gearbox with small tooth difference, comprising at least two axially rotating gears and at least one eccentric counterweight, wherein the axially rotating gears have unequal numbers of teeth and are installed offset in the axial direction, and radial and axial balance is achieved through the mounting structure of the eccentric counterweight and the axially rotating gears, characterized by the following: In the axial-plane coordinate system, the x-axis is the center of the input shaft, and the origin is the left end of the input shaft of all eccentric moving parts. All eccentric parts are distributed at 180° on the upper and lower sides of the x-axis. All eccentric parts on the upper and lower sides of the x-axis have a common equilibrium point on the x-axis. The equilibrium point is defined as the point on which the torques on both sides are equal. The formula for the position of the equilibrium point p of all eccentric parts on the same side on the x-axis is: where x is the horizontal distance of the center of mass of all eccentric parts from the origin of the x-axis, W is the mass-radius product, i.e. the mass multiplied by the eccentricity, of each eccentric part, and the mass-radius products ∑W on both sides of the x-axis are equal. i are equal.

2. The transmission according to claim 1, characterized in that: It contains at least four gears. Gears A1 and A2 are fixed-axis gears, and gears B1 and B2 are axial revolving gears. An eccentric component drives the axial revolving gears to mesh with the fixed-axis gears. Gear A1 meshes with gear B1, and gear A2 meshes with gear B2. Gear B1 has N teeth, gear A1 has N+Q teeth, gear B2 has N+M teeth, and gear A2 has N+M+Q teeth, where M≥1, Q=1 or Q=2. The gear combinations include one of the following: First, the fixed-axis gears are fixed together, with one axial revolving gear fixed and not rotating, while the unfixed axial revolving gear drives the output shaft. Second, the axial revolving gears are synchronously fixed in their rotation direction, with one fixed-axis gear fixed and not rotating, while the unfixed fixed-axis gear drives the output shaft. Third, the axial revolving gears are fixed together, with one fixed-axis gear fixed, while the unfixed fixed-axis gear drives the output shaft.

3. The transmission according to claim 1, characterized in that: The eccentric counterweight can be adjusted and positioned in the axial position during installation to accommodate the different angular momentum of the shaft-centric revolution gears caused by installation errors in different batches. Alternatively, the eccentric counterweight and all other eccentric moving parts and the input shaft can be corrected on a dynamic balancing machine as a whole before use. The correction method includes adjusting the mass of the eccentric counterweight or adjusting the axial position of the eccentric counterweight, having one or a combination of the above two features.

4. The transmission according to claim 2, characterized in that: Based on the four gears, add at least two more gears: a fixed-axis gear A3 and a central rotating gear B3. The central rotating gear B3 is driven by an eccentric shaft to mesh with the fixed-axis gear A3. The number of teeth of the central rotating gear B3 is N+P, and the number of teeth of the fixed-axis gear A3 is N+P+Q, where P≥1, Q=1 or Q=2; or add more sets of gears in this way.

5. The transmission according to claim 1, characterized in that: The gears in the transmission include a pin gear, which includes a pin gear housing and pin teeth. The pin gear housing contains tooth grooves, and the pin teeth are rolling bodies that can roll along the tooth surface of the tooth grooves in the pin gear housing. The transmission also includes a device to prevent the pin teeth from falling out of the tooth grooves of the pin gear. The device to prevent the pin teeth from falling out may include one or a combination of more than one of baffles, flanges, and annular guards.

6. The transmission according to any one of claims 1, 2, 3, 4, or 5, characterized in that: The transmission includes a structure that forces the surrounding fluid to flow, or the transmission includes centrifugal blades, or the transmission housing has heat dissipation fins, or a portion of the transmission housing is made of aluminum or copper, or the transmission housing has heat dissipation fins containing aluminum or copper, or the ends of the eccentric counterweight in the transmission are streamlined, or the transmission includes centrifugal blades driven by the input shaft, or the transmission includes a flow guiding structure that directs the flow of fluid, having one or a combination of the above structures.

7. The transmission according to claim 1, 2, 3, 4, or 5, characterized in that: It also includes a clutch C, the installation structure of which includes: the first type is that the rotation of one gear is fixed by switching the clutch C, and the output is provided by the other gear; the second type of installation structure is that the output gear ratio can be switched according to the external load or machine needs, including one of the above two clutch structures, or a combination of the two structures.

8. The transmission according to any one of claims 1, 2, 3, 4, or 5, characterized in that: The design schemes for the tooth profile curve of the tooth groove or the tooth profile curve of the gear include the following schemes: at least one tooth profile curve contains a circular arc curve, or at least one tooth profile curve contains a cycloid, or at least one tooth profile curve contains an elliptical curve, or at least one tooth profile curve contains an elliptical cycloid, or at least one tooth profile curve contains a straight line, or at least one tooth profile curve contains an involute, or at least one tooth profile curve contains a conical curve, or includes a helical gear, or includes a pair of helical gears with opposite helical directions; including one or more of the above schemes.

9. The transmission according to any one of claims 1, 2, 3, 4, or 5, characterized in that: The transmission works in conjunction with the engine to form a power output module. The engine can be an electric motor or a turbine, wherein the electric motor can be an axial flux motor, an external rotor motor, or an internal rotor motor.

10. The transmission according to any one of claims 1, 2, 3, 4, or 5, characterized in that: The transmission is used in a transmission system, and its application scenarios include, but are not limited to, propeller drive, hub drive, or mechanical actuators. The mechanical actuators can be used in, but are not limited to, rotary joints of industrial machinery, wearable robotic arms, reciprocating transport machines, embodied intelligent machines, vehicle steering systems, aircraft steering rudder transmission systems, ship steering rudder transmission systems, or the transmission can be used in electric vehicles or electric construction machinery.

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