Expansion of Ratio Range of Shaft Drive CVT by Using Zero-Spin Disk

Author(s):  
Yukihito Narita ◽  
Masashi Yamanaka ◽  
Katsumi Inoue

The novel mechanism CVT (Shaft Drive CVT, S-CVT) was developed by the authors. It transmits power by a traction drive same as the half toroidal CVT. S-CVT has parallel input/output shafts with conical or concave disks and the idler shaft having conical rollers at both ends, which is placed perpendicularly to the input/output shafts. All disks and rollers can move along each axis directions, and these movements produce the ratio changing by the changes of the rotational radii. The efficiency is the key evaluation function of CVT. To improve the efficiency, the backup roller mechanism was devised. Its effectiveness was confirmed by the experiment, and the efficiency of 95% was obtained by modified prototype S-CVT. This paper deals with the expansion of ratio range of S-CVT. In case of using the present disks, S-CVT has a difficulty to expand the narrow ratio range of 4 (0.5 to 2) because of the large slip brought by the spin. To expand the ratio range, the zero-spin disk/roller was devised. The shape of zero-spin disk/roller satisfies the condition that the spin does not occur at any speed ratio. According to the calculation, the slip rate becomes less than 1% at any speed ratio. To confirm the effectiveness, the prototype S-CVT with zero-spin disk was manufactured. It has the ratio range of 0.43 to 2.35. To obtain the slip rate the experiments were carried out at the speed ratio of 0.43, 1 and 2.35. At each speed ratio, the slip rate of less than 1% was obtained, and the effect of the zerospin disk was confirmed.

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1691 ◽  
Author(s):  
Zhenzhen Chen ◽  
Donghui Wen ◽  
Jianfei Lu ◽  
Jie Yang ◽  
Huan Qi

For the traditional single-side planetary abrasive lapping process particle trajectories passing over the target surface are found to be periodically superposed due to the rational rotation speed ratio of the lapping plate to workpiece that could affect the material removal uniformity and hence its surface quality. This paper reports on a novel driving system design with combination of the tapered roller and contact roller to realize the irrational rotation speed ratio of the lapping plate to workpiece in the single-side planetary abrasive lapping process for the improvement of surface quality. Both of the numerical and experimental investigations have been conducted to evaluate the abrasive lapping performance of the novel driving system. It has been found from the numerical simulation that particle trajectories would theoretically cover the whole target surface if the lapping time is long enough due to their non-periodic characteristics, which can guarantee the uniformity of material removal from the surface of workpiece with relatively high surface quality. The encouraging experimental results underline the potential of the novel driving system design in the application of the single-side planetary abrasive lapping for the improvement of the surface quality in terms of surface roughness and material removal uniformity.


Author(s):  
Yingxin Yang ◽  
Chunliang Zhang ◽  
Lian Chen ◽  
Yong Liu

For improving the drilling efficiency of polycrystalline diamond compact drill bit, a novel polycrystalline diamond compact drill bit is presented with a new rock-breaking method named as cross-scraping. In the novel polycrystalline diamond compact drill bit which is referred to as a composite drill bit, polycrystalline diamond compact cutters are mounted on rotary wheels as major cutting elements, and as a result, mesh-like scraping tracks are formed in the outer radial area of the bottom-hole. Rock-breaking method of the composite drill bit causes both shearing and fracture failure of the bottom-hole rock, which will greatly increase the rock-breaking efficiency and will prolong the bit service life. By analyzing the complex motion of cutters on the composite drill bit, velocity and acceleration models of the cutters, as well as wheel/bit speed ratio model of the bit are established in accordance with the geometric relationship between cutters and bit body in a compound coordinate system. In simulation examples, motion tracks, velocity and acceleration features of the cutter and especially the bottom-hole pattern are analyzed. Further, indoor experiments are conducted to test the mesh-like bottom-hole pattern and rock-breaking features, which have proved the accuracy of the analysis model of the composite drill bit.


2018 ◽  
Vol 241 ◽  
pp. 01020
Author(s):  
Mikhail E. Semenov ◽  
Olesia I. Kanishcheva ◽  
Peter A. Meleshenko ◽  
Olga O. Reshetova ◽  
Roman E. Pervezentzev ◽  
...  

In this work we introduce the novel class of hysteretic operators with random parameters. We consider the definition of these operators in terms of the “input-output” relations, namely: for all permissible continuous inputs corresponds the output in the form of stochastic Markovian process. The properties of such operators are also considered and discussed on the example of a non-ideal relay with random parameters. Application of hysteretic operators with stochastic parameters is demonstrated on the example of simple oscillating system and the results of numerical simulations are presented.


Author(s):  
Teng Wang ◽  
Kevin Vasko ◽  
Zhuo Liu ◽  
Hui Chen ◽  
Weikuan Yu
Keyword(s):  

1999 ◽  
Vol 122 (4) ◽  
pp. 523-528 ◽  
Author(s):  
Y. Zhang ◽  
X. Zhang ◽  
W. Tobler

This paper presents a systematic model for the design and analysis of toroidal traction drive continuously variable transmissions (CVT). The contacts between the input disk, the roller and the output disk of the traction drive are formulated using the classical Hertzian contact theory. The traction force and side slip force occurring in CVT operation are modelled based on the elasto-hydrodynammic theory and are correlated to the traction drive geometric and kinematic parameters. The model allows for the quantitative analysis of traction drive operation under various torque inputs and over the desired ratio range. [S1050-0472(00)01004-7]


1984 ◽  
Vol 106 (4) ◽  
pp. 305-310 ◽  
Author(s):  
H. Tanaka ◽  
T. Ishihara

Continuously variable automatic transmissions can bring improved fuel economy benefits under good speed ratio changes for automobile propulsion systems in which engines can produce their power under optimum conditions. These systems require computer control for the calculation of optimum speed ratio. The paper presents design features of the electrohydraulic interface between micro-computer and cone-roller toroidal traction drive CVT, dynamic characteristics of cone roller motion, and test results of the practical computer control of CVT.


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