Tribological properties of polymer-sheet-adhered metal hybrid gear

A preliminary study was made on the tribology of nylon 66/poly(phenylene ether) polymer sheets adhered to steel gear teeth against a counter steel gear with reference to friction, surface morphology, noise reduction and torque in comparison with a pair of steel gears lubricated with molybdenum grease. Tribological experiments were performed in a gear-testing machine at a rotating speed of 1000 rpm under high torques of the driving and driven gears, recording torque of each gear and noise-frequency profiles. It was found that periodical torque changes in a range of 17–5 N m at 1000 and 3000 cycles (revolutions) turned to 13–8 N m at 5000 cycles, indicating a change to stable cycle and torque conduction, probably due to a plastic surface deformation of the adhered polymer sheet for a smooth contact of pairing teeth. A harsh noise emission in the frequency range of 3–5 kHz was reduced circa 5 dBA as compared with a pair of steel/steel gear. It was found, however, that noise abruptly increased when only one of the adhered polymer sheets was spontaneously removed from the gear surface, probably because of its low adhesive strength against a shear during gear cycle.     

修形斜齿圆柱齿轮弹流润滑的优化设计

从减小齿轮啮合周期中啮合刚度的波动和改善载荷分布出发,人们已经提出了各种修形方式;本文则从改善齿面间弹流润滑状况的角度,以对角修形为例,优化修形量,以取得最佳润滑效果。     

JS315型减速机振动噪声的研究

齿轮箱的振动和噪声能够反映齿轮装置的品质,影响齿轮箱振动和噪声的因素有齿轮啮合、轴系变形、箱体精度以及安装误差等因素,其中齿轮啮合是主要因素,而齿轮的基节偏差和齿形偏差又是影响齿轮传动平稳性的主要因素。通过对公司JS315型减速机振动和噪声的研究,分析了影响齿轮箱振动和噪声的因素,找出了造成振动和异响的原因,成功解决了这一问题。     

Projektieren der zykloidenverzahnungen hydraulischer verdrängermaschinenDesign of cycloidal gears in hydraulic machines

Cycloidal gears are of great importance in the design of positive displacements machines. They are frequently called gerotor gears, without the design technique, gearing type or gear profile being differentiated. There are, however, different types of these gears with different gear profiles. Thus general design techniques for these types of gears may be determined.

There are two methods of cycloidal gear design: the external envelope technique and the internal enveloped technique, with the first one usually being applied. With this technique, the external gearing of the base gear first and then according to it, the internal gearing of the mating gear are determined. The most beneficial solution is the one shown in Fig. 5, where the external gearing of the base gear is designed on the basis of being equidistant to the curtailed epicycloid and the internal mating gearing has the form of circles (rollers). This type of gear is employed, by Danfoss among others in orbit motors (low-speed orbitrary motors) and control modules for the steering systems of traction vehicles.

The internal envelope technique is, as a matter of fact, the inversion of the external envelope technique. First, the internal basic gearing and then, the external mating are formed. This technique is used rarely and is regarded as the complementary one except for a special case of the hypocycloidal gears in which the internal base gear is formed in accordance with the curtailed hypocycloid and the external mating gearing has the form of circles (rollers). This special case is shown in Fig. 9. This type of gearing is applied by Rexroth in its MZ type low-speed motors.     

Geometrical aspects of double enveloping worm gear drive

Double enveloping worm gearing is expected to have contact over larger number of teeth and higher load carrying capacity compared to single enveloping worm gearing. In this paper, contact in this gearing is analysed by geometrical simulation of worm gear tooth generation using intersection profiles of different axial sections of worm representing the hob tooth profile with transverse plane of worm gear. The analysis reveals that in the engaging zone a straight line contact always exists in the median plane and intermittent contact exists at the extreme end sections of worm. This has lead to the idea of using two fly cutters positioned at the location identical to the extreme end sections of worm to generate full worm gear tooth thereby eliminating the need for hobs of complex geometry. For a given worm, a mating worm gear is machined in a gear hobbing machine using fly tool in two settings and nature of contact with the worm is checked by a blue test.     

基于热弹变形的圆柱齿轮理想修形曲线

提出一种求解圆柱齿轮理想修形曲线的方法，应用耦合热弹接触有限元技术，分析轮齿在齿间载荷分配、齿面压力分布、轮齿弹性变形、齿面摩擦、轮齿温度场、轮齿制造误差因素作用下齿轮传动的啮合刚度，尽可能真实地模拟运转过程中啮合轮齿的形态，确定轮齿的刚度变化规律，通过数值拟合寻求最佳修形参数，在此基础上，得到圆柱齿轮理想修形曲线。     

Evaluation of the strength,wear, and durability of a corrected cylindrical involute gearing,with due regard for the tooth engagement conditions

A method for calculating the wear and durability of helical gearings is used to investigate the effect of double–single–double tooth engagement on the maximum contact pressures, tooth wear, and durability of a corrected cylindrical involute gearing under constant tooth contact conditions. A technique is presented for determination of the angles of transition from the doubleto the single-tooth contact and vice versa. Gear tooth profile correction is found to reduce the maximum contact pressures by up to 20%. The teeth of the gear wheel reach their wear allowance faster than those of the pinion do. Depending on the degree of correction, the maximum wear occurs at different characteristic contact points: at the entry to the double-tooth mesh, at the entry to the single-tooth mesh, or at the exit out of the mesh. The durability of the gearing is found to be at its maximum at certain overlap ratios, its magnitude being observed to increase substantially (by up to 50%). The results obtained are presented in graphic form, which enables one to reveal the laws governing the effect of the engagement conditions.     

渐开线齿轮支座强迫振动的研究

通过系统的研究充分表明,由于齿间存在摩擦,渐开线齿轮支座反力必发生周期性变化;为此,渐开线齿轮支座会产生一定程度的强迫振动,其程度与齿间滑动摩擦系数齿轮传动的重迭系数密切相关。     

渐开线齿轮机构输出扭矩波动率与齿间滑动摩擦系数及齿数之关系

传统的渐开线齿轮理论不计齿间摩擦的影响,它认为,只要主动轮输入扭矩保持恒定,则从动轮输出扭矩也维持不变。研究充分表明,即使渐开线齿轮机构主动轮输入扭矩保持恒定不变,但齿间摩擦的存在,会使其从动轮输出扭矩发生一定的波动;输出扭矩的波动率将与齿间滑动摩擦系数及齿轮齿数密切相关。这里研究结果指出：采取积极有效措施减小齿间滑动摩擦并适当增加齿轮齿数是促使渐开线齿轮机构输出扭矩保持平稳的重要途径。     

齿根动态应力分析

齿根应力分析是齿轮设计的一个主要问题,啮合过程中齿根应力分布特性是衡量齿付传动性能的主要指标。本文讨论了直齿圆柱齿轮在啮合过程中有关轮齿刚度、齿面载荷分配、以及齿根应力的计算方法。并通过实验进行分析。同时对修形齿轮与非修形齿轮作了对比分析实验。证明对重载齿轮进行修形能有效地改善齿根应力特性。     

Technological solution to profile and generate the teeth of central gear for precessional gear drives

The transmission based on precessional gear pairs, mostly used for rotation speed reduction, has some important advantages relative to the common gear drives, such as the capability to produce very low transmission ratios, or the high loading capacity/dimensions ratio (due to the fact that all the teeth of a precessional gear pair are simultaneously in contact during its functioning). One among the likeliest constructive solutions for the precessional gear pair uses a satellite built with conical rollers. However, its practical use is restricted by the difficulty to realize the central gear teeth machining without using special and relative complicated devices. This paper introduces a technological substitutive profile for the central gear tooth, which enables the use of a simpler and more productive method for working it, without bringing major negative consequences regarding the teeth contact correctness or the drive loading capacity. The profile was found by analyzing the contact surface and the pressure angle evolution during the contact between conjugate teeth. The paper also presents technological solutions to generate the new tooth profile by milling it with a disk-tool or an end-mill cutter, together with methods to profile the required tools.     

摆线针轮行星传动的运动平稳性分析

分析了摆线轮有加工误差或修正的齿廓与针轮针齿的啮合瓣关系。建立了摆线针轮行星传动瞬时传动比的计算式。根据计算所得的瞬时传动比变化曲线可看出一组可 种传动因加工误差或齿廓修正将导致传动出现运动不平稳性,所作分析将为改善摆线针传动的啮合牧场考了参考。     

齿轮传动动态系统辨识及修形研究

利用自动控制理论研究实际工况下齿轮传动的动态性能, 通过系统辨识算法, 建立了直齿圆柱齿轮传动周向振动和噪声之间的差分方程模型, 此模型能够准确描述齿轮传动系统的动态特性。根据齿轮传动周向振动和轮齿变形之间对应关系, 对降低齿轮传动噪声的齿廓修形曲线进行了优化设计, 并进行了试验验证。为齿轮传动系统的修形、减振、降噪和优化设计提供了一种新的研究方法。     

凸轮激波复式活齿传动的结构及齿形分析

提出一种新颖的大速比传动装置——凸轮激波复式滚动活齿传动装置，该传动装置由一级NGW型行星传动机构与一级凸轮激波的二齿差滚动活齿传动机构串联组成。对其传动原理、传动比及传动特性进行了分析，以此为基础设计了装置的传动结构。导出了中心内齿轮的齿形方程，给出了齿形计算示例，并进一步分析了相关参数对齿形几何性质的影响。     

平面一次包络环面蜗杆副齿间载荷分配研究

平面一次包络环面蜗杆两侧工作齿面为直纹曲面,利用这一特点提出了建立蜗杆副准确的三维实体模型的方法.完成了一对平面一次包络环面蜗副的精确三维实体模型,然后以中间格式导入ABAQUS.利用有限元法分析接触载荷在轮齿之间的分布,发现接触载荷从啮入到啮出过程是逐渐减小的.利用有限元法研究了母平面倾角β对于接触载荷分布的影响,发现在蜗杆齿面不出现非啮合区的前提下,β较大时载荷分布更均匀.     

齿轮副端面重合度统一定义及其计算式

针对各种齿轮传动提出端面重合度的统一定义,并且推导其计算表达式,进一步讨论了渐开线齿轮副、微线段齿轮副和正弦齿廓齿轮副的端面重合度的计算问题。齿轮副的端面重合度定义为齿轮作用角（即一对轮齿从进入啮合到脱离啮合过程中齿轮所转过的角度）与齿轮的齿距转角的比值。根据齿轮啮合原理,由基本齿条的轮廓曲线能够获得其啮合线方程。根据所获得的啮合线方程,以及给定的齿轮副齿顶线方程,就能够根据本文的计算式得到齿轮副的重舍度。对于渐开线齿轮副,该定义与众所周知的“啮合线长度与基节之比”的结果相同。该定义同样适用于非渐开线齿轮副,例如微线段齿轮副、正弦齿廓齿轮副等,而且计算结果更可靠。     

基于润滑降噪实验的车床挂轮噪声分析

以一台C630车床空转噪声的测试数据为依据,分析了齿面摩擦对车床挂轮噪声的影响,以及摩擦激励频率与齿轮啮合频率的关系,并通过涂油润滑降低挂轮噪声的实验对此进行了验证。结果证明:齿面摩擦对齿轮振动的激励频率是啮合频率的2倍,可以利用适当的润滑有效地抑制齿轮噪声的高频成分。     

基于Morlet小波的时频图在齿轮断齿故障诊断中的应用

齿轮传动系统振动信号带有明显的非平稳性,齿轮断齿故障使非平稳特征更加明显,并伴有明显的脉冲冲击特性。利用小波分析处理非平稳的优势,结合齿轮传动系统的振动特性和Morlet小波能够处理脉冲信号的特点,建立了基于Morlet小波的时频分析方法,通过对某齿轮增速箱齿轮断齿故障的诊断,证明本方法不但能够准确诊断出断齿故障,而且能够评估断齿数量,较好地弥补了传统频谱分析的不足。研究结果对于齿轮断齿等具有脉冲信号特征的故障诊断具有一定的指导意义。     

Tribology of polymer injection-molded stainless steel hybrid gear

In order to verify our hypothesis proposed from the previous paper where a polymer sheet-adhered metal hybrid gear has superior properties of antiwear, self-lubrication and noise reduction, studies were first made on a possibility of nylon66/poly(phenylene oxide) (PPO) alloy injection-molding onto shot-blasted aluminum and steel disks. Adhesion of the coated polymer layer to the metal surfaces and no crack formation of the polymer layer were found under certain molding conditions. This molding method was then applied to a stainless steel spline, a sort of gears used in clutches, giving rise to adhesion of the coated polymer alloy without surface crack formation of the resultant hybrid gear. Tribological properties of the hybrid gear were examined by a vibrational test under a severe condition of a predetermined acceleration amplitude of 10 G and a frequency of 100 Hz. A very high antiwear was found in the hybrid gear, while a same type of stainless steel gear without polymer coating showed a severe wear not only on the gear teeth but also on the meshing teeth of the counter stainless steel disk. Taking into consideration excellent tribological properties with antiwear, self-lubrication and noise reduction, it is concluded that the injection-molded hybrid gear is promising for a wide range of industrial applications.     

Dynamic characteristics analysis and experimental research on a new type planetary gear apparatus with small tooth number difference

Aimed at an internal mesh planetary gear with small tooth number difference (PGSTD) reducer, this paper proposes dynamic characteristics analysis. First, static finite element (FE) analysis is performed to check the structural strength with the stress distribution in the gear teeth. Second, by means of the dynamic contact FE method, the internal dynamic excitations of teeth mesh are obtained, including mesh stiffness excitation, transmission error excitation and mesh impact excitation. According to the established model for dynamic FE modal analysis, the natural frequencies and mode shapes of the planetary gear apparatus (PGA) are calculated, and its structural dynamic response and acceleration noise are researched with the comprehensive consideration of internal and external excitations. Finally, the noise and vibration testing on the PGA is carried out by utilizing the vibration test equipment. The results confirm that the predicted values are consistent with the experimental results.