Lubrication methods and structures of vibratory shaft bearings of vibratory rollers at home and abroad
The vibration roller is produced by the rotation of the vibration shaft with eccentric block in the vibration wheel. The bearing supporting the vibrating shaft works under high-speed and heavy load, and also meets the requirements of large bending due to the vibrating shaft. At present, the bearings of vibration shafts at home and abroad mostly adopt double row centripetal spherical self-aligning roller bearings. The bearing working under high-speed and heavy load in the closed vibrating wheel is easy to heat up, resulting in seizure and damage. Therefore, reasonable lubrication and cooling methods must be adopted to improve the service life of the bearing and prolong the maintenance time of the vibratory roller. Therefore, we analyze and compare the lubrication methods and structures of the vibration bearings of the imported and domestic vibratory rollers, and on this basis This paper introduces the lubrication structure we use on yzj141 and other models.
At present, the lubrication methods and structures of vibratory shaft bearings of vibratory rollers at home and abroad include:
1. Grease lubrication
It relies on the pressure injection cup at the shaft end of the vibrating shaft, presses the grease with an oil grab, and then enters the bearing through the central oil passage of the vibrating shaft for lubrication, as shown in Figure 1. For example, the lubrication of bearings of domestic yzt14 and Italian simeca towed vibratory roller is an intermittent pressure grease lubrication. It can only be applied to the case of low rotating speed of vibrating shaft, and its lubrication performance and cooling effect are poor The bearing is easy to heat and has low service life. Its advantage is that the structure of the sealing device is relatively simple. This lubrication method is not used on self-propelled vibratory rollers.
2. Spray lubrication
The bearing is pressurized directly by the oil pump, and the bearing is sprayed and lubricated through the oil pipe (Fig. 2). For example, sismopactor850 vibratory roller of French albaret company. This is a better lubrication method, but it needs to add a set of oil pump ridge system. And because the vibrating wheel and vibrating shaft are moving parts, it brings some difficulties to the setting of this system. Therefore It is not widely used in other vibratory rollers.
Figure 1
1. Drive pulley 2. Oil cup 3. Oil passage 4. Pneumatic tire 5. Eccentric block
3.Bearing oil overflow lubrication
An oil bag is arranged at the bearing in the vibrating wheel, and the rolling element at the bottom of the bearing is not lubricated in thin oil [Fig. 3]. This is a continuous non pressure lubrication, which is mostly used on self-propelled vibratory rollers at home and abroad. Such as domestic yzj10, CA25 of ruiqu Dynapac company, etc. It is much better than grease lubrication in lubricating performance and cooling effect. In this lubrication structure, the eccentric block is submerged in the oil in the oil package. When the vibration shaft rotates, the eccentric block stirs in the oil. According to the theory of fluid mechanics, the moving object will be subject to the resistance of the fluid in the fluid. Its resistance is:
Figure 2
1. Damping block 2. Eccentric block 3. Transmission motor 4. Oil pipe
Figure 3
1. Oil drum 2. Vibrating shaft 3. Eccentric block
It can be seen that when the lubricating oil to be used is determined, the resistance of the moving object in the oil is directly proportional to the quadratic power of the moving speed of the object and the first power of the upstream area of the object. The larger the upstream area and the higher the speed of the eccentric block stirred in the oil, the greater the resistance and the more energy and power consumption. The bearing gets lubrication in the oil. Because the bearing stirs the oil, it will also bring energy loss, resulting in the temperature rise and heating of the oil and bearing. The loss of energy will increase the load of the vibration pump and engine, which are unfavorable.
In view of the problems existing in the above lubrication structure, we should seek a simple and energy-saving lubrication structure. According to the relationship between the resistance of the moving body in the fluid, we improve the lubrication structure from the following aspects;
1) Reduce the upstream area or the moving body does not stir oil;
2) Select the low-speed moving part as the oil stirring moving part
3) Increase the oil package and improve the heat dissipation conditions.
The improved lubrication structure is as follows:
1. Use the oil pan to throw oil for lubrication
The large oil bag is used, and the oil slinging disc placed on the vibrating shaft is used to shed oil to lubricate the bearing (Fig. 4). Here, only the oil slinging disc stirs the oil, the eccentric block is not immersed in the oil, the upstream area of the moving body in the oil is reduced, the resistance and energy consumption are reduced, and the heat dissipation conditions are good. However, in the test, we found that reducing the upstream area is not the most positive measure, because the oil slinger is installed on the vibrating shaft, the speed is high, and the linear speed of the oil slinger is high, which still consumes a lot of energy and power, so we designed the following structure.
Figure 4
1. Oil pan 2. Vibrating shaft 3. Eccentric block 4. Oil drum
2. Scoop oil lubrication for low-speed moving parts
On the vibrating wheel of the vibratory roller, the vibrating shaft is a moving part rotating at high speed, while the vibrating wheel and oil bag are moving parts at low speed. Therefore, a two-way oil scooper is set on the circumferential wall of the oil drum moving at a low speed, which can scoop up the oil in the oil drum regardless of whether the vibrating wheel rotates in the forward or reverse direction, and then spray the oil to the bearing through the oil pipe (Fig. 5). This is a continuous pressure (potential energy) lubrication. Since the oil scoop is installed on the oil bag that moves at a low speed, the eccentric block does not stir the oil, and the stirring resistance of the moving parts is greatly reduced. For example, for a medium-sized vibratory roller, if the speed of the vibratory wheel is 100r / min and the speed of the vibratory shaft is 1800r / min, the oil scoop with the same speed as the vibratory wheel is more than the eccentric block stirring oil on the vibratory shaft. At the same upstream area, the radial diameter of the oil scoop is twice the diameter of the eccentric block stirring oil, so the motion resistance should be reduced by 81 times, greatly reducing the consumption of energy and power. Therefore, this structure is good in terms of lubrication performance, cooling effect and heat dissipation conditions, as well as energy saving, and is a feasible lubrication device.
Figure 5
1. Vibrating shaft 2. Eccentric block 3. Oil bag 4. Oil pipe 5. Oil scoop
3. Bearing oil lubrication
Like the above bearing oil immersion lubrication, it relies on the lowest rolling element of the bearing immersed in the oil to obtain lubrication. The difference is that the eccentric block of this structure is not installed in the oil drum, and the surface is outside the oil drum < Figure 6). Its purpose is to avoid moving parts stirring oil in the oil tank, which can also achieve the effect of energy saving. However, this structure is sometimes limited by the form of support configuration, and there is also the problem of sealing.
Figure 6
1. Vibrating shaft 2. Eccentric block 3. oil bag
In a word, the structure of the vibrating shaft bearing of the vibratory roller will directly affect the lubrication, cooling performance and energy saving, which should be paid attention to.
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