Yu Chengtao, Xu Longxiang, Yu Xudong
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J Tribol. 2014 Jan;136(1):111021-111028. doi: 10.1115/1.4024844. Epub 2013 Aug 6.
The mechanical model of a "Z" type double-decker ball bearing under the action of radial load is established in this paper on the basis of the Hertz contact theory. According to the security contact angle theory, the influences of inner and outer bearings' internal clearances on the bearing's static load carrying capacity, radial deformation, radial stiffness, and load distribution of balls are analyzed. This model is verified in both stationary and rotational loading experiments. Moreover, the simulation results show that the static load carrying capacity of Z type bearing is smaller than that of either inner bearing or outer bearing that is contributed to compose the Z type bearing. The static load carrying capacity of a Z type bearing reduces with the increase of the inner and outer bearings' internal clearance. These simulation results also indicate that the contact angle of the maximum loaded ball in the outer bearing easily exceeds its security contact angle compared with the inner bearing, which, as the main factor, may cause the Z type bearing to overload and to fail. In this sense, the investigated Z type bearings are unfit to apply to situations with heavy load, high speed, or high precision.
本文基于赫兹接触理论建立了“Z”型双层球轴承在径向载荷作用下的力学模型。依据安全接触角理论，分析了内、外轴承的内部游隙对轴承静承载能力、径向变形、径向刚度以及滚珠载荷分布的影响。该模型在静态和旋转加载实验中均得到验证。此外，仿真结果表明，Z型轴承的静承载能力小于组成该Z型轴承的内轴承或外轴承的静承载能力。Z型轴承的静承载能力随内、外轴承内部游隙的增大而降低。这些仿真结果还表明，与内轴承相比，外轴承中最大承载滚珠的接触角更容易超过其安全接触角，这可能是导致Z型轴承过载和失效的主要因素。从这个意义上讲，所研究的Z型轴承不适用于重载、高速或高精度的工况。
