Worm gear mechanism with switchable backdrivability

Takayama, Toshio; Hisamatsu, Naoto

doi:10.1186/s40648-019-0149-7

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…whereas the key benefit of a worm gear transmission lies in its ability to achieve substantial velocity and torque ratios within a compact configuration using just one gear set. This setup permits the utilization of a high-velocity motor in scenarios requiring slow motion, eliminating the need for intricate gear arrangements to transfer torque [19]. In a worm drive, a screw-like gear known as a worm meshes with a worm gear, resembling a spur gear or wheel.…”

Section: Worm Gearmentioning

confidence: 99%

Selection guidance of electrical actuation with different gearheads for power-off load latching

Redekar,

Deb

2024

Electr Eng

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The actuator serves as a motion converter, helps transform the speed and direction of motion, and is a motion controller for precise positioning. The actuator facilitates automated movement and is pivotal in determining the machine's performance. Engineers must consider three factors when choosing an actuator: the motor capacity, the reduction ratio of the gearbox, and an encoder. Electro-mechanical actuators fulfill various functions, including precise component positioning, maintaining desired positions, providing ample force or torque for securing closure mechanisms, and enabling controlled acceleration and deceleration at specified speeds. While on power, they excel at holding the desired position, but under off-power conditions, they also securely hold the load in place with less energy consumption. The main objective is to choose an ideal motor and gearhead combination for effectively holding the load when the power is off. This selection process considers crucial factors like output torque, speed, peak power, mass, and size. The research involves a comparative analysis between power-on load holding and power-off load holding in terms of consumed power, control circuitry, stability, and cost. Analytical calculations for finding the optimal motor torque and gearhead (gearbox) are conducted, and a Simscape Multibody simulation of a pendulum system is performed for validation purposes. This study helps select a suitable motor gearhead combination for power-off load holding by comparing the calculated values with simulation results. The method presented here is universally applicable to different types of loads, providing a valuable tool for selecting the most appropriate motor gearhead combination.

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Section: Worm Gearmentioning

confidence: 99%

Selection guidance of electrical actuation with different gearheads for power-off load latching

Redekar,

Deb

2024

Electr Eng

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“…Researchers have developed devices which reduced friction by vibration [6][7][8]; however, these studies do not focus on backdrivability of reducers. Our research group has proposed switching backdrivability by exciting the gear surface [9], eliminating the need for sensors. Apart from the clutch mechanism, the proposed method does not shut down the power transmission path, reducing the risks of secondary disaster.…”

Section: Introductionmentioning

confidence: 99%

“…Apart from the clutch mechanism, the proposed method does not shut down the power transmission path, reducing the risks of secondary disaster. Takayama et al examined the switching backdrivability in worm gears [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Switching backdrivability of a planetary gear by vibration: design parameter setting and excited force estimation

Noda,

Igari,

Endo

et al. 2023

Robomech J

Self Cite

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Switching backdrivability according to use status is important to attain energy-saving and compliance in co-worker robots. Authors have proposed switching backdrivability by exciting gear surface, eliminating the need for sensors while switching. We have confirmed that exciting 2K-H planetary gear can switch its backdrivability. To systematically design the switching backdrivable 2K-H planetary gear, this study reveals less back-drive condition and the required torque for a vibrator. In the less-backdrivable condition, the tooth number difference between the fixed and output gears is dominant. Furthermore, the required torque for the vibrator increases as the load of the output shaft and the vibration frequency increase. The experimental results of the less-backdrivable condition and the required torque for the vibrator are almost entirely consistent with simulation result of the mechanical model

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“…The transmission performance of traditional hourglass worm drive is susceptible to manufacturing and assembly errors, the accuracy requirements and the cost of tools used for machining worm are also high [10][11]. Moreover, the worm gear mechanism and the tooth contact analyzation have received increasing attention [12][13][14]. Therefore, to improve the transmission performance of worm pair, it is necessary to develop the worm pairs with novel transmission types in mechanical engineering.…”

Section: Introductionmentioning

confidence: 99%

Theoretical modeling and transmission characteristics analysis of a novel double-roller hourglass worm drive based on enveloping principle

Gao,

Wang

2023

Preprint

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Traditional planar double-enveloping hourglass worm pairs have the characteristics such as the strong bearing capacity, high transmission efficiency and long life-span. However, the high relative sliding velocity and the serious agglutination or abrasion may also occur at the contact point on tooth surfaces. In this paper, a novel type of double-roller hourglass worm pair is proposed and analyzed, wherein, the worm part adopts from the planar double-enveloping worm pair, the corresponding meshing tooth surface of worm gear is replaced by two rows of cylinder rollers for reducing friction and enhancing meshing efficiency. That is, the original meshing tooth surfaces in worm gear are replaced by the common tangent plane of rollers to form a special type of meshing drive, the original line-contact form between tooth surfaces was changed to point-contact so that the sliding friction was transformed into rolling friction, and the meshing efficiency can be greatly improved. The theoretical model of double-roller hourglass worm pair was established based on spatial enveloping principle, the meshing equation and tooth surface equations were derived. The solid models of worm and gear were established and assembled. The parameters of enveloping surface angle, roller radius and friction coefficient, which affecting relative motion velocity at meshing contact point and efficiency during the whole transmission process was analyzed and discussed systematically. The results showed that comparing to the traditional worm pair, the roller’s rotation greatly reduced the relative sliding velocity and improved meshing efficiency at the contact point in this double-roller hourglass worm pair.

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Worm gear mechanism with switchable backdrivability

Cited by 9 publications

References 15 publications

Selection guidance of electrical actuation with different gearheads for power-off load latching

Selection guidance of electrical actuation with different gearheads for power-off load latching

Switching backdrivability of a planetary gear by vibration: design parameter setting and excited force estimation

Theoretical modeling and transmission characteristics analysis of a novel double-roller hourglass worm drive based on enveloping principle

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