结论：转动部件的失效是渐进的，使用者最先感到的是「变沉」

轮椅上的转动部件包括：后轮轮毂轴承、前脚轮的转向轴承与轮轴、折叠关节、扶手和脚踏的翻转轴。

这些部件的失效很少是突然断裂，更常见的是逐渐劣化——转动阻力增大、出现旷量、产生异响。 对手动轮椅使用者来说，阻力增大意味着推行更费力，这是直接的体验下降。

而这种劣化是渐进的，使用者往往适应了而不觉得，直到明显异常才发现。

主要失效模式

失效模式 原因 表现
润滑失效 润滑脂流失、变质 阻力增大、异响
密封失效 密封件老化、破损 进水进尘，加速磨损
磨损 长期运行、异物侵入 旷量增大、噪音
腐蚀 进水、汗液、清洁剂 卡滞、锈蚀
疲劳 交变载荷 滚道剥落
异物缠绕 毛发、纤维缠入 转动受阻

最后一行是轮椅上的高发问题，尤其是前脚轮。毛发和纤维缠绕在轮轴处，逐渐积累，最终导致转动受阻甚至损坏密封。

这个问题的解决在设计上——轮轴处的防缠结构、便于清理的结构。测试时可以把这个场景纳入：在轮轴处预置纤维，运行一定里程后检查影响。

寿命测试的设计

设计这类测试要确定几件事：

载荷。 按额定载荷的实际分配设定，前后轮承载不同。

运行里程或转数。 按预期使用强度和寿命年限折算。

路面条件。 平路、颠簸路面对轴承的载荷谱不同。建议包含冲击工况。

转向动作。 脚轮的转向轴承有独立的运行次数，要单独计。

环境。 是否包含淋水、粉尘。这对密封件的考察是必要的。

评价指标。 运行前后的转动阻力、旷量、噪音、以及拆解后的磨损状态。

转动阻力的变化是最有实际意义的指标，因为它直接对应使用者的体验。建议测试前后都测，用变化幅度而不是绝对值来评价。

润滑与密封

这两项决定了转动部件的实际寿命：

润滑。 润滑脂的类型要匹配工况——温度范围、载荷、转速。低温下过稠的润滑脂会增加阻力；高温下流失快的润滑脂寿命短。

密封。 密封的作用是防止润滑脂流失和外部污染进入。密封越严阻力越大，这里又是一个权衡。

维护性。 是否可以补充润滑、是否可以更换轴承。免维护设计简化了使用，但失效后只能整体更换。

对于长期使用的产品，可维护的设计通常更经济，前提是维护点容易接近、并且说明书写清楚了维护要求。

环境因素

实际使用中的几个环境因素对转动部件影响明显：

水。 雨天、清洗、洒落的液体。进水后润滑脂乳化、部件锈蚀。

粉尘与沙。 进入后成为磨料，加速磨损。

汗液与体液。 具有腐蚀性。

清洁剂。 可能溶解润滑脂或腐蚀密封件。

建议寿命测试中包含环境因素，纯净条件下的寿命数据会明显高于实际。具体做法是在运行过程中周期性地引入淋水或粉尘，之后继续运行。

与使用体验的关系

转动阻力的变化对不同使用者的影响程度不同：

手动轮椅自主驱动的使用者影响最大，因为推行完全靠上肢力量，阻力增加直接转化为疲劳。

电动轮椅的影响表现在续航上，阻力增加使电机负荷上升，单次充电的行驶距离缩短。

照护人员推行的场景影响中等，但长期推行的累积负担仍然存在。

所以对于以省力为卖点的产品，转动阻力的长期保持能力是实质性的性能指标，值得测试并在资料中体现。

脚轮的特殊问题

前脚轮是转动部件中问题最集中的位置，单独说几点：

摆振。 速度较快时脚轮出现左右摆动，影响操控和舒适。这与转向轴承的阻尼、脚轮的偏置距、以及轮子的质量分布都有关。测试时可以在不同速度下观察摆振出现的阈值。

转向阻力。 阻力过大时转向费力，过小时方向不稳。这个平衡需要通过测量转向力矩来确定。

越障能力。 小直径脚轮遇到门槛、地砖缝隙时容易卡住。轮径、轮宽、材料硬度都影响越障表现。

异物缠绕。 前面提到过，是高发问题。

清洁可及性。 结构是否便于清除缠绕物和污垢。

这几项在常规的强度测试里都不涉及，但对使用体验的影响比强度更直接。

数据怎么用

寿命测试的数据有三个用处：

确定维护周期。 根据阻力上升的曲线，判断多久应当检查或润滑。

支撑产品宣称。 如果宣称耐用或者免维护，需要数据支撑。

指导设计改进。 拆解后看磨损位置和形态，能判断问题出在哪——是润滑不足、密封失效、还是载荷设计偏小。

第三项在开发阶段价值最大。 建议寿命测试结束后不要只看「有没有坏」，而是拆开来看磨损形态。同样是失效，滚道剥落和锈蚀腐蚀指向完全不同的改进方向。

折叠关节的特殊考虑

折叠关节与轴承的工况不同，需要单独看：

运行次数少但载荷大。 折叠动作每天几次，但关节在展开状态下承受整车载荷。

旷量的影响直接。 关节旷量增大会使整车产生晃动感，影响使用信心。

锁定可靠性是安全项。 展开后的锁定失效会导致车架突然折叠，后果严重。

测试重点因此不同：折叠循环次数按实际频次设定即可，但每个循环后要检查锁定的可靠性和旷量的变化。

建议的做法是：折叠循环与承载测试交替进行——折叠若干次后加载，检查锁定是否仍然可靠、旷量是否在可接受范围。单纯做折叠循环而不加载，反映不出实际风险。

噪音作为诊断信号

转动部件的噪音变化是有用的诊断信息，测试中值得记录：

新品的基线噪音。 作为对比基准。

运行过程中的变化。 噪音出现或增大的时点，往往对应某个劣化的开始。

噪音的性质。 持续的摩擦声、周期性的咔哒声、间歇的异响，分别指向不同的问题。

这项在日常使用中也有价值。 说明书里可以提示：出现新的异响时应当检查，不要等到明显卡滞。这个提示成本为零，但能帮使用者更早发现问题。

我们的做法

做转动部件的寿命测试时，我们建议包含两项常被省略的内容：环境因素的引入（淋水、粉尘），以及纤维缠绕场景。 这两项对应的是实际使用中最常见的劣化原因，纯净条件下的数据会偏乐观。

评价指标上，建议以转动阻力的变化幅度为主，辅以旷量和拆解检查。阻力变化直接对应使用者感受，比单纯看「有没有坏」更有信息量。

有需要可以把产品结构和预期使用强度发过来一起设计测试，或者直接联系：132 4819 8029。检测能力见服务介绍，产品分类见手动轮椅检测与电动轮椅检测，案例见案例。

English version

Conclusion. Rotating components on a wheelchair include rear hub bearings, front castor swivel bearings and axles, folding joints, and the pivots of armrests and footrests. These rarely fail by sudden fracture. Far more commonly they degrade gradually, with rotational resistance rising, play developing and noise appearing. For a self-propelling manual wheelchair user, greater resistance means more effort to push, which is a direct decline in experience. Because the deterioration is gradual, users often adapt without noticing until something is obviously wrong.

Failure modes. Lubrication failure, from grease loss or degradation, produces higher resistance and noise. Seal failure, from aged or damaged seals, admits water and dust and accelerates wear. Wear, from prolonged running and ingress of foreign matter, produces play and noise. Corrosion, from water, perspiration and cleaning agents, produces stiffness and rust. Fatigue under alternating load produces raceway spalling. And entanglement of hair and fibres obstructs rotation.

Entanglement is a frequent problem on wheelchairs, particularly at front castors. Hair and fibres wind around the axle, accumulate over time, and eventually obstruct rotation or damage the seal. The remedy lies in design: anti-wrap features at the axle and construction that can be cleared easily. The scenario can be built into testing by pre-placing fibre at the axle and checking the effect after a defined distance.

Designing life tests. Several things must be settled. Load, set from the actual distribution of rated load, since front and rear carry differently. Distance or revolutions, converted from expected duty and service life. Surface conditions, since smooth and rough surfaces impose different load spectra on bearings, and impact conditions are worth including. Steering action, since castor swivel bearings accumulate their own cycle count and must be counted separately. Environment, specifically whether water spray and dust are included, which is necessary to assess seals. And evaluation measures: rotational resistance, play and noise before and after, plus wear condition on disassembly. Change in rotational resistance is the most meaningful measure because it corresponds directly to user experience; measure before and after and evaluate by the magnitude of change rather than absolute values.

Lubrication and sealing. These two determine real service life. On lubrication, grease type must match the duty in temperature range, load and speed; grease too thick at low temperature raises resistance, while grease that migrates at high temperature has a short life. On sealing, the purpose is to retain grease and exclude contamination, and tighter sealing means higher resistance, which is another balance. On maintainability, consider whether lubrication can be replenished and whether bearings can be replaced; sealed-for-life designs simplify use but must be replaced entirely on failure. For products in long-term service, maintainable designs are usually more economical, provided the maintenance points are accessible and the instructions state the requirements clearly.

Environmental factors. Several strongly affect rotating components in use. Water, from rain, washing and spillage, emulsifies grease and rusts components. Dust and sand act as abrasive once inside and accelerate wear. Perspiration and body fluids are corrosive. And cleaning agents may dissolve grease or attack seals. Include environmental factors in life testing, since life data obtained in clean conditions come out markedly higher than reality; in practice, introduce water spray or dust periodically during running and then continue.

Relationship to user experience. Changes in rotational resistance affect users differently. Self-propelling manual users are affected most, since propulsion depends entirely on upper limb strength and added resistance converts directly into fatigue. For powered chairs the effect appears in range, as added resistance raises motor load and shortens the distance per charge. Where a carer pushes, the effect is intermediate, though the cumulative burden of prolonged pushing remains. For products sold on ease of propulsion, therefore, the ability to maintain low rotational resistance over time is a substantive performance measure worth testing and documenting.

How we handle it. For life testing of rotating components we suggest including two things commonly omitted: environmental factors such as water spray and dust, and the fibre entanglement scenario. Both correspond to the most common causes of deterioration in use, and clean-condition data come out optimistic. For evaluation we suggest leading with the magnitude of change in rotational resistance, supported by play measurement and inspection on disassembly, since resistance corresponds directly to what users feel and carries more information than simply whether something has broken.

Send us the construction and expected duty and we will design the test. Phone or WeChat: +86 132 4819 8029.