Worm gear-worm pair backlash eliminating device adopting enveloping worm

Abstract

The invention relates to a worm gear-worm pair backlash eliminating device adopting an enveloping worm, which mainly consists of a worm gear, a cylindrical worm, the enveloping worm, an elastic pre-tightening device and a bearing. The cylindrical worm and the enveloping worm play the main force scale division role and the resistance role respectively, and the two worms are coaxially mounted and carry out the regulation and impose the pre-tightening force on a resistance worm in the axial direction through the elastic pre-tightening device. The pre-tightening device consists of a regulating nut, two spring positioning sleeves and a pre-tightening spring, regulates and pre-tightens the resistance worm in the axial direction through the regulating nut. The elastic pre-tightening device can be one of a spring device, a hydraulic device or a pneumatic device. The resistance enveloping worm and the main force worm are coaxially mounted in the worm gear-worm pair backlash eliminating device, and the axial regulation and the pre-tightening are carried out on the resistance worm through the elastic pre-tightening device, thereby providing the more stable, high-efficient and low-noise transmission and simultaneously having the advantages of compact structure, light weight, low cost and the like. The worm gear-worm pair backlash eliminating device is applied in a transmission mechanism of a rotary workbench of a machine tool and can provide better backlash eliminating effect in comparison with a single worm gear-single worm mechanism or a double-worm gear-worm mechanism.

Description

technical field [0001] The invention belongs to a mechanical transmission device, in particular to a backlash elimination device for a worm gear and worm pair using a toroidal worm, which is suitable for the field of mechanical transmission. Background technique [0002] Worm gear transmission has the advantages of compact structure, large transmission ratio, stable operation, small impact and vibration, and reverse stroke self-locking. In worm gear transmission, proper tooth side clearance can avoid the phenomenon of extrusion or jamming caused by deformation of gear teeth under force and expansion due to friction and heat; it can provide a space for lubricating oil, which is convenient for tooth surface lubrication, etc. However, due to the existence of tooth backlash, it will inevitably bring shock, vibration, noise to the worm gear transmission, and reduce the system's follow-up accuracy and stability. The fit gap between the worm gear and the worm due to manufacturing ...

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Problems solved by technology

[0003] At present, in order to improve the transmission accuracy of worm gears, the usual method is to improve the machining accuracy and installation accuracy of worm gears. This method has a limit to the improvement of accuracy and greatly increases the manufacturing cost.

However, there are generally three types of worm gear transmissions for eliminating or adjusting the tooth backlash: "double worm transmission" (Cao Xijing, Zhang Chun, Liu Changqi, Li Ning. Application of double worm transmission in precision numerical control indexing [J]. Shaanxi Science and Technology University Journal, 2003, 21(7): 70-72.) (Qiu Xinqiao. Double worm transmission mechanism that can reduce the transmission gap. Mechanical Manufacturing, 2003, 41(7): 51-51), Gleason, USA The driving device of Pufa special CNC gear hobbing machine table adopts double worm gears, and the double worms are assembled in parallel up and down, and the backlash is eliminated by axially adjusting the worm as the resistance; similar structures have two parallel or vertical installations on a single worm gear. side, through the axial adjustment of one of the worms to achieve the effect of anti-backlash, this type of structure usually needs to increase the gear transmission between the two worms to realize the synchronous movement of the two worms, and also need to increase the worm bracket to realize the two worms during installation. The matching of the relative positions between the two worms will cause problems such as bloated structure of the transmission device, lengthening of the transmission chain, and high manufacturing cost.

[0004] "Double-lead Cylindrical Worm Drive" (Qian Guangjin. New Technology and New Process. No. 5, 1983), the double-lead cylindrical worm drive is to adjust the tooth side clearance of the transmission by adjusting the axial position of the worm to compensate for the gear teeth The amount of thinning due to wear, this transmission has been used in precision indexing mechanisms such as gear hobbing machines at home and abroad. Its main disadvantages are: the processing of worm gears is difficult, the number of teeth in contact between the worm gear and the worm meshing transmission is small, the bearing capacity is low, and it is easy to wear , short life, etc., it is difficult to meet the requirements of heavy-duty precision transmission

For example, the "Precise Worm Gear and Worm Transmission Backlash Elimination Device" with patent application number 200610102244.6, "a worm gear and worm transmission device" with patent application number 200510050421.6, etc. Although these transmission devices can eliminate backlash, there are generally many transmission elements, Insufficient in large volume, complex structure or insufficient bearing capacity

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