1."跳挡"的原因
1. Reasons for "gear tripping"
(1)变速传动机构磨损W4-60型挖掘机上采用的是机械换挡变速的传动机构，这种传动机构是依靠滑动齿套在固定齿套上作轴向移动并与各挡的从动齿轮相啮合来实现换挡的。在频繁的换挡过程中，上述各啮合齿轮的轮齿端面易被磨成锥形，造成其啮合性能降低而导致"跳挡"。
(1) Wear of variable speed transmission mechanism w4-60 excavator adopts the transmission mechanism of mechanical shift and variable speed. This transmission mechanism relies on the sliding gear sleeve to move axially on the fixed gear sleeve and mesh with the driven gear of each gear to shift. In the process of frequent gear shifting, the tooth end face of the above meshing gears is easy to be grinded into a cone, resulting in the reduction of their meshing performance and "gear skipping".
(2)自锁机构的性能下降为防止变速器"跳挡"，该型挖掘机在变速器的Ⅱ、Ⅲ挡和Ⅳ、Ⅴ挡拨叉轴上方的箱盖孔内和Ⅰ、倒挡拨叉内均安有起自锁作用的钢球及弹簧。当起定位自锁作用的弹簧其弹性减弱或折断时，自锁机构的自锁性能会下降直消失，造成变速器"跳挡"。同时，定位钢球或拨叉轴上的凹槽若出现磨损，也可造成变速器"跳挡"。
(2) The performance of the self-locking mechanism decreases. In order to prevent the transmission from "jumping gear", this type of excavator is equipped with self-locking steel balls and springs in the box cover hole above the shift fork shafts of gears II, III, IV and V of the transmission and in the shift forks of gears I and reverse. When the elasticity of the spring acting as positioning self-locking is weakened or broken, the self-locking performance of the self-locking mechanism will decline until it disappears, resulting in "gear jump" of the transmission. At the same time, if the groove on the positioning steel ball or shift fork shaft is worn, it can also cause the transmission to "skip".
(3)换挡装置调整不当该型挖掘机的变速器采用的是机械式人力换挡的方式，若变速杆、纵轴、横轴及竖固定螺钉松动亦可造成变速器"跳挡"。
(3) Improper adjustment of the shift device. The transmission of this type of excavator adopts mechanical manual shift. If the shift lever, longitudinal axis, transverse axis and vertical fixing screws are loose, the transmission can also "skip".
(4)外界负载突然变化由于挖掘机的工作性质及该机自身的设计原因，外界负载的突然变化也会导致其变速器"跳挡"。当路面凸凹不平、机器作下坡行驶或行驶路线不当而使外界负载突然发生变化时，这种负载的突然变化会通过车轮、传动轴作用在变速器的挡位啮合齿轮上，使挡位啮合齿轮因产生轴向推力而脱开，造成变速器"跳挡"。
(4) Sudden change of external load due to the working nature of the excavator and the design of the machine itself, the sudden change of external load will also lead to the "skip" of its transmission. When the external load changes suddenly due to uneven road surface, downhill driving of the machine or improper driving route, this sudden change of load will act on the gear meshing gear of the transmission through the wheel and transmission shaft, so that the gear meshing gear will disengage due to axial thrust, resulting in "gear jump" of the transmission.
(5)操作方法不当挖掘机在坡道上行驶(尤其是下坡行驶)时，如果操作不当，也会导致变速器"跳挡"。
(5) Improper operation method when the excavator is driving on a ramp (especially downhill), improper operation will also cause the transmission to "jump gear".
2.预防措施
2. Preventive measures
(1)严格按照操作规程和驾驶要领进行操作，尽量避免换挡时"打齿"，以减少齿轮副的磨损。
(1) Operate in strict accordance with the operating procedures and driving essentials, and try to avoid "tooth beating" during gear shifting, so as to reduce the wear of gear pair.
(2)严格执行保养制度，加强换挡装置的维护保养。当换挡装置杆系连接不当时应及时调整，确保换挡装置性能良好。
(2) Strictly implement the maintenance system and strengthen the maintenance of shift device. When the linkage of the shift device is not connected properly, it shall be adjusted in time to ensure good performance of the shift device.
(3)注重对自锁机构的维修与保养，对定位作用降低或失去定位效能的定位钢球、弹簧及拨叉轴，应及时修复或更换，使自锁机构的自锁性能处于良好的状态。
(3) Pay attention to the repair and maintenance of the self-locking mechanism. The positioning steel ball, spring and shift fork shaft with reduced positioning function or lost positioning efficiency shall be repaired or replaced in time to make the self-locking performance of the self-locking mechanism in a good state.
(4)组装变速器时，应严格按操作规程进行操作，确保变速器各机件调整正确、紧定适当。较大的下坡路面时，驾驶员应严格按照下坡的动作要领进行操作，切不可违规。
(4) When assembling the transmission, it shall be operated in strict accordance with the operating procedures to ensure that all parts of the transmission are adjusted correctly and tightened properly. In case of large downhill road, the driver shall operate in strict accordance with the action essentials of downhill, and shall not violate the rules.
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