Steering engine speed reduction transmission system and method based on linear gear

Abstract

The invention relates to a steering engine speed reduction transmission system and method based on a linear gear. The transmission system comprises a shell assembly, a driving motor, an output shaft and a speed reduction mechanism. The speed reducing mechanism is arranged in the shell assembly and is configured to transmit the output torque of the driving motor to the output shaft; the speed reducing mechanism comprises at least one level of linear gear pair, and the linear gear pair is formed by meshing a driving linear gear and a driven linear gear; and the driving line gear and the driven line gear are respectively generated by a preset space curve and a conjugate curve thereof, and form point contact pure rolling in the meshing transmission process. Through cooperation of all the mechanisms, the single-stage large-transmission-ratio design is achieved through the small tooth number by means of the characteristic that a linear gear is free of undercutting limitation. Compared with a steering engine adopting an involute gear, the friction loss is reduced, the vibration noise is reduced, the structure compactness is improved, and the steering engine is suitable for micro steering engines, robot joints, precise executing mechanisms and other scenes.

Description

A servo motor reduction transmission system and method based on linear gears Technical Field

[0001] This invention relates to the field of servo motor transmission and gear reduction technology, specifically to a servo motor reduction transmission system and method based on linear gears. Background Technology

[0002] Servo motors are a type of servo actuator that reduces the output of a motor to produce controllable angular displacement or angular velocity. They are widely used in robotics, drones, model aircraft, medical equipment, and industrial automation. With the rapid development of modern robotics, aerospace, and medical devices, stringent requirements have been placed on the miniaturization, high power density, and control precision of servo motors.

[0003] Existing servo gear reduction mechanisms typically use involute gears as transmission elements. Involute gears have advantages such as a mature standard system and good interchangeability, but they still have the following limitations in miniaturization and high-performance applications: (1) Sliding friction and efficiency loss: Involute gears have unavoidable sliding friction during meshing. This relative sliding leads to energy loss and generates heat and wear, limiting the lifespan of the servo in high-frequency reciprocating motion; (2) Undercutting phenomenon and volume limitation: In miniaturization scenarios, in order to obtain a larger overall transmission ratio, the number of teeth on the driving gear needs to be reduced, but involute gears are prone to undercutting, which limits the lower limit of the number of teeth, resulting in the need to increase the number of stages / use complex displacement modification, causing an increase in the number of parts, a longer dimensional chain, and an accumulation of assembly errors; (3) Noise and vibration: Under high-frequency or variable load conditions, transmission errors and meshing stiffness fluctuations may cause noise and vibration, affecting control accuracy and quiet performance; (4) Insufficient degree of freedom for customized optimization: The involute tooth profile is constrained by a fixed generation law, and the comprehensive optimization space for specific center distance / structural space / noise index is limited.

[0004] To address the aforementioned issues, effectively resolving frictional losses, size limitations, and noise problems in servo motor transmissions, and improving transmission efficiency and compactness, has become a key problem to be solved in the field of precision transmission technology. Summary of the Invention

[0005] To address the problems existing in the prior art, the purpose of this invention is to provide a servo gear reduction transmission system and method based on linear gears, which can reduce friction loss and noise in servo gear transmission, and improve transmission efficiency and structural compactness.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a servo gear reduction transmission system based on linear gears, comprising: a housing assembly; a drive motor mounted on the housing assembly; an output shaft rotatably supported on the housing assembly; and a reduction mechanism disposed within the housing assembly, configured to transmit the output torque of the drive motor to the output shaft; the reduction mechanism includes at least one linear gear pair, the linear gear pair being formed by the meshing of a driving linear gear and a driven linear gear; the driving linear gear and the driven linear gear are respectively generated by a preset spatial curve and its conjugate curve, and the two form point contact pure rolling during the meshing transmission process.

[0007] Furthermore, the reduction mechanism includes an input shaft gear connected to the drive motor and an output shaft gear connected to the output shaft.

[0008] Furthermore, the reduction mechanism also includes an intermediate transmission assembly rotatably supported on the housing assembly. The intermediate transmission assembly is provided with an intermediate linear gear, and the input axis gear, the intermediate linear gear and the output axis gear are connected in series and meshed.

[0009] Furthermore, the intermediate gear includes a first double-linked gear and a second double-linked gear arranged in parallel; both the first double-linked gear and the second double-linked gear are double-linked structures including a large gear and a small gear arranged coaxially; the input axis gear meshes with the large gear of the first double-linked gear; the small gear of the first double-linked gear meshes with the large gear of the second double-linked gear; and the small gear of the second double-linked gear meshes with the output axis gear.

[0010] Furthermore, the preset space curve is either a cylindrical helix or a conical helix, or a combination thereof.

[0011] Furthermore, the tooth profile of the spur gear pair satisfies the geometric constraint of no undercut, and the minimum number of teeth of the driving spur gear is 1.

[0012] Furthermore, the meshing overlap ratio of the spur gear pair is greater than or equal to 1.

[0013] Furthermore, the housing assembly is provided with a bearing housing, and the output shaft is rotatably supported on the bearing housing through the bearing assembly.

[0014] A servo gear reduction transmission method based on linear gears includes the following steps: S1: Determine the contact curve of the driving linear gear according to a preset spatial curve, and calculate the conjugate contact curve of the driven linear gear according to the conjugate meshing principle to generate a linear gear pair; S2: Drive the driving linear gear to rotate by a drive motor, and transmit power to the driven linear gear through point contact pure rolling meshing of the linear gear pair to achieve speed reduction and torque increase; S3: Transmit the final output torque to the output shaft through the series transmission of multi-stage linear gear pairs.

[0015] In step S1, the number of teeth of the drive gear is designed to be an integer greater than or equal to 1 in order to obtain a single-stage large transmission ratio without undercut.

[0016] In general, the present invention has the following advantages: (1) extremely high transmission efficiency: by utilizing the pure rolling characteristics of linear gears, the sliding friction of the tooth surface is eliminated in principle, thereby reducing power consumption and heat generation.

[0017] (2) Miniaturization and weight reduction: Utilizing the characteristic of linear gears without undercutting limitations, the minimum number of teeth on the drive gear can be designed to be 1. Under the same transmission ratio requirements, the number of gear stages or the gear diameter can be significantly reduced, significantly improving the compactness and power density of the servo motor. This reduces the overall size and weight of the servo motor reduction mechanism.

[0018] (3) Low noise and high stability: Pure rolling contact significantly reduces meshing impact and running noise, and improves the control accuracy and stability of the servo motor. Attached Figure Description

[0019] Figure 1 illustrates the geometric design principle and conjugate curve generation of the parallel axis gear in this invention. It shows the generation process of the cylindrical helix and its conjugate curve. Figure 2 shows the parallel axis gear pair model in this invention, illustrating the meshing state of the driving and driven linear gears. Figure 3 is a cross-sectional view of the overall structure of the servo motor reduction transmission system based on linear gears provided in this embodiment of the invention, showing the motor, gearbox, and internal layout. Figure 4 is a schematic diagram of the reduction mechanism structure of this invention, showing the connection relationship of the three-stage gear transmission.

[0020] In the figure: 1-Outer shell assembly; 11-Upper shell; 12-Middle shell; 13-Lower shell; 2-Drive motor; 3-Reduction mechanism; 31-Input shaft gear; 32-First double-coupling gear; 33-Second double-coupling gear; 34-Output shaft gear; 4-Intermediate transmission assembly; 41-First intermediate shaft; 42-Second intermediate shaft; 5-Bearing assembly; 6-Output shaft. Detailed Implementation

[0021] The present invention will now be described in further detail.

[0022] Referring to Figures 1 to 4, the present invention provides a servo speed reduction transmission system based on linear gears, which mainly includes a housing assembly 1, a drive motor 2, a bearing assembly 5, an intermediate transmission assembly 4, a speed reduction mechanism 3, and an output shaft 6.

[0023] In this embodiment, in order to adapt to the flat shape of the servo motor, the reduction mechanism adopts a parallel axis gear transmission layout.

[0024] Specifically, the outer casing assembly 1 includes an upper casing 11, a middle casing 12, and a lower casing 13, which are fastened together with screws to form a closed gearbox. The drive motor 2 is fixedly installed inside or connected to the middle casing 12. The bearing assembly 5 (including several precision miniature bearings) is interference-fitted into a pre-set bearing seat inside the outer casing assembly 1. The intermediate transmission assembly 4 includes a first intermediate shaft 41 and a second intermediate shaft 42, the two ends of which are respectively supported in the outer casing assembly 1 to support the stable rotation of the reduction gear.

[0025] In one specific embodiment, the reduction mechanism adopts a three-stage reduction scheme, including an input axis gear 31, a first double-coupling gear 32 disposed on a first intermediate shaft 41, a second double-coupling gear 33 disposed on a second intermediate shaft 42, and an output axis gear 34.

[0026] Both the first and second double-linked gears are double-linked structures consisting of a large gear and a small gear arranged coaxially. They can be integrally formed, keyed, or interference-fitted. The large gear and the small gear are spaced apart along the axial direction to fit the housing space and avoid interference. The gears can be made of metal or self-lubricating engineering materials, and can be used with grease, solid lubrication, or low-oil lubrication solutions.

[0027] The input shaft gear 31 is connected to the output shaft of the drive motor 2. The output shaft gear 34 is coaxially fixed with the output shaft 6. The output shaft 6 is supported between the upper housing 11 and the middle housing 12 by the bearing assembly 5 and extends outside the housing to connect to the load. The end of the output shaft 6 may be provided with a spline, flat section or keyway connection structure for connecting to the servo rocker arm or output flange.

[0028] In one specific embodiment, the specific connection relationship and transmission path are as follows: the input axis gear 31 meshes with the large gear of the first double-linked gear 32; the small gear of the first double-linked gear 32 meshes with the large gear of the second double-linked gear 33; and the small gear of the second double-linked gear 33 meshes with the output axis gear 34.

[0029] All gear pairs are linear gears, with their tooth profiles generated by spatial curves (such as cylindrical helices) and their conjugate curves. The meshing point satisfies the pure rolling condition. The curve parameters can be flexibly adjusted to adapt to different layouts such as parallel shafts, intersecting shafts, or staggered shafts.

[0030] In one specific embodiment, in order to achieve extreme miniaturization, the input axis gear 31 is designed as a single-start (Z=1) line gear, which meshes with the large gear (e.g., Z=15) of the first double-linked line gear 32, so that a large reduction ratio of 15:1 can be obtained in the first stage, and there is no risk of undercut.

[0031] Under the premise of meeting the target total transmission ratio and structural space, the number of stages can be adjusted to reduce to two stages or expanded to multiple stages; the initial curve can be selected from cylindrical helical lines, conical helical lines and their combinations; under the premise of not changing the meshing principle of linear gears, different shaft support and positioning structures can be adopted.

[0032] A servo gear reduction transmission method based on linear gears includes the following steps: S1: Determine the contact curve (such as a cylindrical helix or a conical helix) of the driving linear gear according to the preset spatial curve R1, and calculate the conjugate contact curve R2 of the driven linear gear according to the conjugate meshing principle to generate a linear gear pair; By adjusting parameters such as the helix angle and curvature of the curve, the contact position, contact line evolution and meshing smoothness can be designed; Under the premise of meeting the geometric constraints of avoiding undercut, the driving gear is allowed to use a small number of teeth, thereby improving the single-stage transmission ratio.

[0033] S2: Drive motor 2 drives the driving spur gear to rotate. Through the point contact pure rolling meshing of the spur gear pair, the power is transmitted to the driven spur gear to achieve speed reduction and torque increase; S3: Through the series transmission of multi-stage spur gear pairs, the final output torque is transmitted to the output shaft.

[0034] Preferably, in step S1, the number of teeth of the drive gear is designed to be an integer greater than or equal to 1 in order to obtain a single-stage large transmission ratio without undercut.

[0035] During operation, when the control system issues a command to drive motor 2 to rotate, the power is transmitted to the input shaft gear 31 via the motor output shaft. The input shaft gear 31 drives the first double-linked gear 32 to rotate through pure rolling contact. Subsequently, the power is transmitted to the second double-linked gear 33 via the pinion of the first double-linked gear 32, and then to the output shaft gear 34 via the pinion of the second double-linked gear 33. After three stages of progressively decreasing speed and increasing torque, the output shaft 6 is finally driven to rotate by the output shaft gear 34, thus driving the external load. Throughout the entire process, due to the use of linear gear pairs, there is no relative sliding between the tooth surfaces, resulting in extremely low friction loss and smooth, low-noise operation.

[0036] This invention combines the rootless and pure rolling characteristics of linear gears with a multi-stage series transmission layout, resulting in a significant synergistic effect.

[0037] First, the undercut-free geometry of linear gears allows the driving gear to have an extremely small number of teeth (as small as 1), enabling a single-stage transmission ratio of over 15:1 with a very small center distance, which is significantly higher than that of traditional involute gears that are limited by undercut. On this basis, the single-stage transmission ratio is multiplied by a multi-stage series layout, thereby achieving a total transmission ratio far exceeding that of traditional schemes in an extremely compact and flat space.

[0038] Secondly, the point contact pure rolling during the meshing process of linear gears eliminates the sliding friction loss of each stage of transmission in principle, which significantly improves the efficiency of single-stage transmission. In multi-stage series transmission, this efficiency advantage is multiplied and amplified. The total efficiency improvement after three stages of transmission is much higher than the simple sum of the efficiencies of a single stage, which significantly reduces energy loss and heat generation.

[0039] In addition, the pure rolling characteristics of linear gears suppress the vibration excitation of each meshing stage from the source, while the intermediate shaft and double gear structure in the multi-stage transmission layout further attenuate the transmission of high-frequency vibrations. The synergistic effect of the two makes the noise and vibration of the servo motor in high-speed reciprocating operation significantly improved.

[0040] In summary, this invention achieves a balance of high reduction ratio, high efficiency, and low noise within a compact space by organically integrating the characteristics of linear gears with a multi-stage transmission layout.

[0041] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A servo motor reduction transmission system based on linear gears, characterized in that, include: Housing components; The drive motor is mounted on the housing assembly; The output shaft is rotatably supported on the housing assembly; And a reduction mechanism, housed within the housing assembly, configured to transmit the output torque of the drive motor to the output shaft; The reduction mechanism includes at least one spur gear pair, which is composed of a driving spur gear and a driven spur gear meshing together. The driving spur gear and the driven spur gear are generated by a preset spatial curve and its conjugate curve, respectively, and they form point contact pure rolling during meshing transmission.

2. The servo gear reduction transmission system based on linear gears according to claim 1, characterized in that, The reduction mechanism includes an input shaft gear connected to the drive motor and an output shaft gear connected to the output shaft.

3. The servo gear reduction transmission system based on linear gears according to claim 2, characterized in that, The reduction mechanism also includes an intermediate transmission assembly rotatably supported on the housing assembly. The intermediate transmission assembly is provided with an intermediate linear gear, and the input axis gear, the intermediate linear gear and the output axis gear are connected in series and meshed.

4. The servo gear reduction transmission system based on linear gears according to claim 3, characterized in that, The intermediate line gear includes a first double-linked gear and a second double-linked gear arranged in parallel; both the first double-linked gear and the second double-linked gear are double-linked structures including a large gear and a small gear arranged coaxially; the input axis gear meshes with the large gear of the first double-linked gear; the small gear of the first double-linked gear meshes with the large gear of the second double-linked gear; and the small gear of the second double-linked gear meshes with the output axis gear.

5. The servo gear reduction transmission system based on linear gears according to any one of claims 1-4, characterized in that, The preset space curve is either a cylindrical helix or a conical helix, or a combination thereof.

6. The servo gear reduction transmission system based on linear gears according to claim 5, characterized in that, The tooth profile of the spur gear pair satisfies the geometric constraint of no undercut, and the minimum number of teeth of the driving spur gear is 1.

7. The servo gear reduction transmission system based on linear gears according to claim 5, characterized in that, The meshing overlap ratio of a linear gear pair is greater than or equal to 1.

8. The servo gear reduction transmission system based on linear gears according to claim 5, characterized in that, The housing assembly contains a bearing housing, and the output shaft is rotatably supported on the bearing housing via the bearing assembly.

9. A servo gear reduction transmission method based on linear gears, applied to the servo gear reduction transmission system based on linear gears as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: Determine the contact curve of the driving linear gear according to the preset spatial curve, and calculate the conjugate contact curve of the driven linear gear according to the conjugate meshing principle to generate a linear gear pair; S2: The drive motor drives the driving linear gear to rotate, and transmits power to the driven linear gear through the point contact pure rolling meshing of the linear gear pair to achieve speed reduction and torque increase; S3: Through the series transmission of multi-stage linear gear pairs, the final output torque is transmitted to the output shaft.

10. The servo gear reduction transmission method based on linear gears according to claim 9, characterized in that, In step S1, the number of teeth of the drive gear is designed to be an integer greater than or equal to 1 in order to obtain a single-stage large transmission ratio without undercut.

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