Abstract: In view of the difficulties in machining the end face grooves of rolling mill roller bearings, the corresponding fixture and tool were designed, and the machining task was successfully completed.

Key words: rolling mill roller bearing; Oil tank; Split plate; positioning

1 Introduction

Rolling mill roller bearing roller and raceway for line contact, radial bearing capacity is large, suitable for bearing heavy load and impact load. Small friction coefficient, suitable for high-speed rotation, limit speed close to deep groove ball bearings. The bearing can move axially, can adapt to the change of the relative position of the shaft and the shell caused by thermal expansion or installation error, and can be used as a free end support. The machining precision of the shaft or seat hole is required to be higher, and the relative deflection of the outer ring axis should be strictly controlled after the installation of the bearing, so as not to cause the concentration of contact stress. The inner ring or outer ring can be separated for easy installation and disassembly.

2 Processing analysis

The new products 313822 and 313824 bearing jackets have been finished in other units. The outer diameter of this product is φ330mm and φ390mm. The weight of each piece is about 19kg. It requires milling workers to process 8 equal R75mm grooves on each end face. The precision of the oil groove is required to be higher, the size and contour tolerance such as bisecting accuracy and symmetry are required to be within 0.05mm, and the finish is up to Ra1.6, which is difficult to process, and this kind of product has never been processed. The size of bearing outer ring of 313822 is shown in Figure 1.

When processing the specimen, the indexing plate is used to clamp, and the curved surface is processed with a book 150 three-edge milling cutter. Due to the large resistance of the milling cutter, the dividing plate produces a gap, luminosity is not good, easy to get stuck, resulting in waste products, and low processing efficiency, the production schedule can not be guaranteed. In view of this situation, the fixture and tool are developed by ourselves, and the equipartition plate (as shown in Figure 2), positioning plate, positioning block, screws, platen, positioning pin and so on are designed successively. The processing of this type of product is successfully completed.

3  Clamp positioning during processing of coat oil groove

After the jig processing is completed, the bearing jacket is drawn out and the cross wire is installed on the dividing plate. This fixture is automatic centering, not easy to hurt the workpiece, clamping firmly. A batch of products only need to draw a product line, reduce the drawing process, at the same time save handling time, reduce labor intensity, solve the problem of clamping and equal division. The jig for processing the first oil groove is shown in Figure 3.

4 turning processing method

After processing a single 8-part oil groove with a fixture, it is necessary to process the 8-part oil groove on the other end. To this end, a positioning device for turning machining is designed to solve the problem of position symmetry of both sides. A T-shaped camber positioning key corresponding to the R75mm oil groove was designed and made, as shown in FIG. 4, and inserted into the bed T-groove. The symmetrical relation between the two surfaces was determined by matching the camber surface of the locating block with the oil groove of the machined surface. In terms of position, the use of the press plate fixed on the bed surface, combined with the cross line on the workpiece, to determine the machining position of the workpiece on the machine tool. With this method, we can process 60 ~ 80 products every day.

5 Tool manufacturing

If you want to process the product quickly and with good quality, you need to work hard on the cutting tool and the amount of cutting, as shown in Figure 5. The original three-sided milling cutter made of tool steel is changed into a flying milling cutter with YTl416×16 alloy blades. This tool has strong durability and reduces the number of inspection and measurement. The rotary speed of flying milling cutter is 600r/min and the feed is 680mm/min when machining on X61W equipment. Every day processing 60-80 products, greatly improve the production efficiency.

6 Closing remarks

Through the design of fixture and tool, the processing of roller bearing end oil groove of rolling mill is successfully completed. The dimensional accuracy, geometric accuracy and position accuracy meet the requirements. The processing efficiency is about ten times higher than that of the degree plate clamping, which lays a solid foundation for the processing of this kind of product.