Digital assembly of the hottest conical bearing

2022-08-22
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Digital assembly of conical bearing

in the assembly of transmission system, the assembly of conical bearing is the difficulty in the whole assembly. The pre tightening mode and pre tightening force of conical bearing directly affect the transmission state of bevel gear and the transmission accuracy of the whole transmission system

only by setting a reasonable bearing preload according to the bearing capacity, speed, operating conditions, etc., can the service life of the transmission system be guaranteed. If the preload is too large, it will consume power and even cause the bearing to overheat. If the preload is too small, there will be a gap between the rolling element and the inner and outer rings under the action of load, causing the transmission shaft to jump and move, reducing the transmission accuracy, increasing the noise, affecting the gear meshing, and seriously damaging the gear teeth and bearings

the bearing is pre tensioned at room temperature, but in the working state, the transmission shaft system will be slightly extended under the influence of oil temperature rise, and the bearing preload will also change. Therefore, this factor should be taken into account when setting the preload

II. Structural form of cone bearing application

in the application of cone bearing, the typical structure is no more than the following three typical structures:

1. Directly pre tighten the inner ring of bearing

compress the inner ring of bearing axially through the rotation of nut, eliminate the clearance between the inner and outer rings, and achieve the purpose of bearing pre tightening. (see Figure 1)

at present, the common method to achieve this purpose is: first, pre tighten the bearing with a force far greater than the final assembly pre tightening force, and then return the nut for 1/4 turn

this assembly method has the advantages of less investment, simple structure and practicality. It can be used on the premise of good consistency of bearing cone rolling quality

disadvantage: no quantitative data. In particular, under the condition of poor cone roll consistency, we will find that the preload of the preloaded bearing according to the above method is unstable, some of which are too large or too small, resulting in unstable assembly quality

2. gasket preloading

through the allocation of gaskets, the bearing clearance is eliminated to achieve the purpose of axial preloading. (see Figure 2)

at present, the commonly used method is: first, pre tighten the bearing with a force far greater than the final assembly pre tightening force, measure the axial dimension, and then subtract about 0.2mm to obtain the gasket value. The advantages and disadvantages of this assembly method are the same as above

3. Deformation pre tightening of bellows

bearing pre tightening is achieved by compressing the deformation of bellows. (see Figure 3)

at present, the commonly used method is: tighten the nut with an air wrench to a torque less than the lower limit. In order to test the material, tighten it with a torque wrench, test the rotating torque, tighten it again, test it repeatedly and alternately, until both torques are qualified

this assembly method has the advantages of less investment and simple structure. It can be used on the premise of good quality consistency of corrugated sleeve and bearing

disadvantage: no quantitative data. In particular, under the condition of poor quality consistency of corrugated sleeve and bearing, the tightening force is often too large, resulting in waste products, resulting in unstable product quality

III. digital assembly

according to the different structural forms of the product drive train, reasonable configuration of solutions is the key to the drive train assembly. Once the plan is unreasonable, it is just like the wrong direction. It is difficult to make things perfect. The incomplete assembly plan will directly lead to the flow of defective products into the market, and repeat mistakes every day. This is also the reason why many manufacturers' annual after-sales costs are rising

in addition, the traditional assembly mode is qualitative assembly, and there is no accurate quantitative evaluation on the digital quantification of product assembly direct reading. Therefore, it is impossible to track and improve the product assembly quality. In view of the above three structural forms, we propose a digital makeup formula. The electronic wood-based panel universal testing machine produced by Jinan new era Testing Instrument Co., Ltd. has the case of wdw-0 to 5000kN electronic wood-based panel testing machine, which has been widely used in the production line

1. pre tighten the inner ring of bearing

for this structural form, the typical application equipment at present are: steering knuckle tightening machine, hub nut tightening machine

working principle: the tightening machine tightens the nut, the sensor randomly tracks the change of the nut torque, synchronously detects the pre tightening torque of the hub bearing, until the pre tightening torque of the hub bearing and the tightening torque of the nut meet the set value. The green window shows qualified; Otherwise, the red window displays unqualified

tightening sensor accuracy: ± 1%

rotation detection sensor accuracy: 0.1%

2. Gasket pre tightening

for this structural form, at present, typical application equipment include: gearbox pad selector, main gear pad selector, differential pad selector, etc

working principle: load through the servo motor, pre tighten the outer ring of the bearing, and synchronously detect the bearing pre tightening force. When the bearing pre tightening force reaches the set process range, stop pressing, axial self-locking, running in, and check to confirm that the torque is qualified for measurement

measurement accuracy: ± 0.015mm

recheck accuracy: ± 0.01mm

3. Bellows deformation pre tightening

for this structure, at present, typical application equipment include: driving gear nut tightening machine, transfer gear driven gear nut tightening machine, etc

working principle: the servo system differentially tightens the large nut and randomly tracks the change of the nut torque. At the same time, the sensor automatically detects and randomly tracks the change of the bearing rotating torque; The actual pre tightening torque value of the bearing and the tightening torque of the nut are displayed, and the process parameters are automatically compared with the set value until the actual torque value of the bearing rotation torque and the tightening torque of the nut reaches the set value. They all play a better energy-saving effect range to varying degrees. The servo motor stops running, and the green light indicates qualified

when the nut is screwed to the minimum process torque, and the bearing rotation torque exceeds the maximum value set by the process, it is judged to be unqualified. If it is loosened, it will prompt that the spacer sleeve is too soft and alarm

when the nut is screwed to the maximum torque of the process, the bearing rotation torque is still not the minimum value set by the process, which is judged as unqualified. If it is loosened, it will prompt that the spacer sleeve is too hard and alarm

tightening sensor accuracy: ± 1%

rotation detection sensor accuracy: 0.1%

IV. cone bearing assembly outlook

the development of modern automobile manufacturing industry has higher and higher requirements for assembly quality. For assembly, it is not only necessary to realize automation, but also important to realize digitization. Product quality assurance first requires a unified quantitative standard for assembly quality evaluation. In order to achieve this standard, digital assembly is inevitable. At the same time, it also provides the most important basis for product development, improvement and assembly quality tracking

we have studied the assembly of conical bearings for many years, and developed corresponding digital assembly concepts and equipment for different assembly structures of conical bearings. Through the application on the production line, the productivity is improved, the labor intensity is reduced, and the assembly quality is improved

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