Failure analysis and maintenance of gearbox

CVT That is, continuous variable transmission. In other words, there is no gear shift, and its transmission ratio is continuous, which is different from the shifting process of constant mesh gearboxes. As a result, the power output is continuous and smooth. Its greatest advantage is that there is no transmission gear and no speed ratio, which will enable the vehicle to maintain the peak torque and maximum efficiency of the engine when it is continuously accelerating. Because the torque of the CVT gearbox is small, the most widely used scooter is the motorbike running on the streets.

Although the gearbox has many advantages, there will be a lot of problems, such as the decline of starting acceleration, the low speed of driving, and the abnormal noise in the gearbox when driving. Therefore, this article focuses on Wuyang Honda WH100T motorcycle as an example, focuses on the causes of the failure of the CVT gearbox, and discusses how to repair.

Start acceleration performance decline

The obvious feature of the fault is that although the throttle has increased and the engine speed has increased, the vehicle has not moved forward or moved slowly.

1. Analysis of the cause of failure

The main reasons for the decline in acceleration performance are: the skidding of the main and the driven pulley, the skid and wear of the belt, the aging, the loosening of the fastening nut of the active pulley, the wear of the centrifugal roller or the small stroke.

2. Troubleshooting

After confirming the fault, the transmission gearbox should be decomposed in turn for inspection. First, check whether the fastening nut of the main pulley is loose. If loosening, it should be tightened to the standard torque (50 ~ 60N. M). Then the active pulley is decomposed to check whether the working cone is abnormal wear or abrasion due to loosening of nuts. If the wear depth is greater than 0.4mm, the active pulley should be replaced. Use caliper (0.20mm) to measure the width of the transmission belt (the standard value is 18.5mm, the limit value is 17.5mm). If the limit is less than the limit value, the qualified Belt should be replaced. After measuring the width of the belt, it should also visually inspect its appearance. If there are cracks, deformation, internal tooth wear, lining belt exposure and cracking, new parts should also be replaced. A caliper is used to measure the inner diameter of the active sliding pulley bushing (the standard value is 20.035 ~ 20.085mm, the limit value is 20.60mm), and the outer diameter of the axle sleeve of the active sliding belt is measured (the standard value is 20.010 to 20.025mm, the limit value is 19.98mm), and if the limit value is less than the limit value, it should also be replaced. Use the caliper to measure the outer diameter of the centrifugal roller and check whether it is less than the limit value (the standard value is 15.92 ~ 16.08mm, the limit value is 15.40mm). If it is, all the roller should be replaced. The roller can't be changed alone, otherwise it will cause the noise. Finally, check whether the fit clearance between the active belt and the axle sleeve is too large or too small. If so, repair or replace the new parts should be carried out. For the check of the driven pulley, the wear of the inner diameter of the sliding driven pulley should be measured first with the caliper (the standard value is 34 ~ 34.025mm) and the limit value is 34.06mm). The wear condition of the outer diameter of the moving wheel is measured with the caliper (the standard value is 33.965 to the limit value should be replaced. " Then check whether the three guide pins and the guide pin grooves on the driven sliding wheels are worn seriously or deformed. If so, the damaged parts should be replaced. The use of driven wheel bearings should also be checked to see if there are any axial or radial clearances or inflexibility in rotation. Use the caliper to measure the free length of the large spring of the driven pulley (the standard value is 124.2mm, the limit value is 105mm), if the limit is less than the limit value, replace the new spring. Check the wear of clutch shoe and check whether there is partial wear or not. The caliper is used to measure whether the thickness is smaller than the limit value of 1.5mm. For hooves, springs should be checked to see if they are elongated or deformed. Finally, check the size of the inner diameter of the driven clutch hub with a caliper (the standard value is 112 ~ 112.2mm, the limit value is 112.5mm) is less than the limit value, if, should also replace the new part.

Inability to drive, low speed

The particularity of the fault is that although the vehicle can drive, the speed can not rise with the increase of engine speed.

1. Analysis of the cause of failure

After confirming the fault, we should check the working condition of the main and driven clutch, whether the driving belt is slippery or there are water stains or oil stains in the gearbox.

2. Troubleshooting

For the overhaul of the above fault, we can refer to the relevant contents of the above section. Here only a little more, it is when the friction sheet of the clutch shoe of a driven pulley clutch is checked or replaced, it should be noted that the thickness, length and weight of the three hoofs must be consistent. Also check whether there is oil or water stains on the surface of the transmission system. If there is oil, it is necessary to check whether the O seal ring on the driven pulley has broken and aging damage. Check whether the oil seal on the main bearing of the crankshaft or the oil seal on the gear reducer is damaged, resulting in the lubrication oil flowing into the transmission box, causing the transmission parts to slip. If there is water stains in the transmission box, check whether the interface of the ventilation window is damaged or not, thus causing the outside water to enter the transmission box, causing slippage.

Abnormal sound in the transmission box during driving

1. Analysis of the cause of failure

The fault is mainly caused by the lack of lubricating oil and the abnormal wear of the transmission bearing, or the bad work of the main and driven pulley and the serious wear of the transmission belt.

2. Troubleshooting

First of all, the amount of lubricating oil in the wheel reducer should be checked. If not, it should be supplemented to standard oil (standard 0.10L, 0.12L). If the fault continues, the emphasis should be placed on the inspection of wheel reducer. First, break it down. Attention: in decomposition