globoid worm

ypical Globoid gear.
Globoid (or Double Enveloping Worm or Hour Glass) gear has globoid worm advantage versus a traditional worm gear due to increased driving efficiency ( 6-10% higher in 25:1 ratio) and increased loading capacity (about 30%).
The disadvantage of a globoid gear is higher manufacturing cost and sensitivity of the enveloping pinion to the axial location.
Due to the geometrical character of the tooth geometry Globoid pinion may mesh not only with the mating enveloping equipment but also with a correctly designed cylindrical helical equipment. Using a helical equipment with a Globoid pinion is definitely common in lower cost in applications such as for example automotive electric powered equipment actuators. The significant price advantage comes due to the possibility to injection mold the helical plastic gear. The load capability of the simplified helical/Globoid transmission is reduced to the level below the strain capacity of the standard worm gear. However the driving efficiency continues to be better compare to the regular worm gear.
There are simply a few suppliers of the Globoid gear. division of Textron, situated in Traverse City, MI. The detailed information regarding processes used at Cone Drive for making of its gear cannot be found. However, based on publicly released info it can be understood that the gear is produced by CNC milling with use a small ball shaped cutter.
Ever-power has capacity to design, prototype and supply Globoid gear items. The expertise of Ever-power is 3-dimentional simulation and modeling of the Globoid and double enveloping tooth geometry. Ever-power 3-dimentional Globoid and double enveloping equipment CAD models can be used in various CNC machining shops for generating globoid gear at considerably reduced cost.
Ever-power Globoid 3-dimentional CAD model.
It needs to be noted that manufacturing of the Globoid equipment is more complex compare to production of the Globoid pinion. The Globoid pinion could be produced in high quantities by turning, whirling or grinding. During the machining procedure for the Globoid pinion the cutting tool needs to be capable to tilt to be able to produce the enveloping shape.
The newer production methods are under advancement. The most promising production approach to the Globoid pinion is continues grinding process, which incorporates a grinding wheel (gemstone or CBN plated) with particular Ever-power simulated geometry. The complication of the novel procedure is the problems with simulation of the geometry of the grinding device. The grinding tooth would have to generate a correct type of the Globoid pinion without tilting therefore the production rate and the production cost would be significantly reduced. Ever-power is rolling out a computer based device for making of 3-dimensional CAD types of grinding tools for high volume creation of the Globoid products.
The most common use of the Globoid gear set was seen in 1961-1989 on automotive steering systems in Italy and in Soviet Union.
VAZ-2101 with Globoid steering technology.
The Globoid pinions have already been produced by grinding with a tilting grinding wheel. The Globoid gears have already been cut by a particular hub, which replicated the shape of the Globoid Pinion. Special machines for producing the slicing hubs have already been developed. Because the modern automotive steering systems began to use classic Bishop or advanced Ever-power variable ratio rack and pinion technology, the demand for the Globoid gears provides been reduced.
Variable ratio technology comparison
Vr-rack technology was introduced:
Before 2000
Underlying mathematical model is based on:
Rack geometry calculation precision is:
Limited by the boundaries of the traditional gear theory
Capability to produce the vr-rack with not involute type for reduced noise
Capacity to generate vr-rack with an increase of ratio gain is:
Cost of vr-rack design is:
Ever-power advanced Adjustable Ratio rack and pinion high ratio gain technology for motor sport racing applications.
Ever-power low sound Variable Ratio rack and pinion not involute technology.
Ever-power pioneered in developing of the next generation of Globoid gears. In 1999 Ever-power introduced a skew axis Globoid gear as a high load capability and increased driving efficiency alternative to the classic Globoid gear.
Ever-power skew axis (wormoid) gear.
It has to be noted that the name WORMOID will not relate with any scientific term and it is a product of Dr. Stepan V. Lunin, who was simply the first in proposing this design and, moreover, he was the 1st who produces an accurate functioning model of the apparatus in 3-dimantional CAD system. The accurate 3-d CAD of the WORMOID equipment has proved the ability of the idea such as for example conjugated transmission actions and significant increase of number of tooth in the get in touch with compare to the classic Globoid gear.
CAD 3-d style of Ever-power wormoid gear.
Ever-power happens to be offering assistance for style and development of products predicated on Ever-power wormoid technology.
It has to be noted that wormoid gear design from Ever-power is actually promising unique advantages compare to the classic Globoid (double enveloping) equipment. One of the obvious advantages is increased load capacity because of increased number of one’s teeth in the mesh. The apparatus torque is certainly carried by more teeth so the load on every individual tooth is reduced. The other apparent advantage is increase driving efficiency. As you can see, the part of the pinion with larger diameter is generating the corresponding part of the gear, that includes a larger diameter as well. Such of unique feature of Ever-power wormoid can be missing in the classic Globoid gear and results in higher sliding velocities and higher friction medication on the classic globoid gear. A skilled in the art engineer would immediately derive possible design advantages of the wormoid equipment. For instance, using of the wormoid gear can significantly reduce price of electric powered aid mechanisms that are generally used on modern automobiles. Because of the bigger driving efficiency, wormoid equipment set can be made with increase ration and provide the same driving efficiency as the original worm or double enveloping worm gear. For example NSK worm equipment steering actuator with a ration of about 20:1 provides about 80% of driving efficiency. The plastic equipment would hold about 80 Hm of torque. An alternative wormoid gear design from Ever-power would be capable to increase the ratio up to 30:1 and the torque on the apparatus up to 150 Hm without increase of the guts distance between the gear and the pinion.


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As one of leading manufacturers, suppliers and exporters of mechanical products in China, We offer reducers, sprockets, industrial and conveyor chain, belts, pulleys, gears, racks, gearboxes, motors, PTO Shafts, taper lock Bushing, vacuum Pumps, screw air compressors and many other products. Please contact us for details.

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As one of leading manufacturers, suppliers and exporters of mechanical products in China, We offer reducers, sprockets, industrial and conveyor chain, belts, pulleys, gears, racks, gearboxes, motors, PTO Shafts, taper lock Bushing, vacuum Pumps, screw air compressors and many other products. Please contact us for details.

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