Abstract: Spherical roller bearing inner ring fill ball mouth was processed originally by horizontal milling machine or vertical milling machine with big labor intensity and low production efficiency . In order to solve the existing problems, the original technology and tooling were improved, the milling machine processing was changed into a boring machine processing, the multi-functional universal fixture for clamping ring and the fixture for clamping the milling cutter were designed , and with the technical transformation of boring machine spindle in order to improve the automation of processing, product quality and production efficiency, and reduce labor intensity.
Key words: fill ball mouth for spherical roller bearings; boring machine; milling machine; multi-functional fixture for boring machine; clamping for milling cutter of boring machine
1. Preface
In the design of self-aligning roller bearings, for assembly needs, a ball mounting port is designed on each small edge of the inner sleeve at both ends of the bearing. The original process stipulated that the ball loading port should be processed using flat milling or vertical milling, which has low processing efficiency and high labor intensity. Therefore, the machining process of the inner sleeve of the self-aligning roller bearing has been improved, and the T9210 boring machine has been technically transformed. A set of multifunctional fixtures and a new clamping milling cutter fixture have been designed to machine the ball mouth of the inner sleeve of the self-aligning roller bearing, making clamping convenient and fast, improving the degree of machining automation and production efficiency, and reducing labor intensity and production costs.
2. Existing problems
According to the assembly requirements, the inner sleeve of the self-aligning roller bearing is symmetrically milled with a ball mounting port on each end face of the inner sleeve, with a 180 ° distance between the retaining edges, as shown in Figure 1. According to different product specifications, the ball loading port is machined on a vertical milling machine or a horizontal milling machine. Taking the machining of 53540H bearing inner sleeve ball mouth with a vertical milling machine as an example, analyze and explain the process machining.
Figure 1 Product diagram of 53540H bearing inner sleeve
2.1 Ball loading processing technology
(1) The selected vertical milling equipment is XD5032. The TS type rotary worktable is fixed on the working platform of the vertical milling machine. A self centering three jaw chuck with a diameter of 300mm is used to fix it on the TS type rotary worktable, and then the machined inner sleeve is fixed by the chuck, as shown in Figure 2.
Figure 2: Machining of Bearing Ball Port with Vertical Milling Machine
(2) The radius of the ball mouth of the 53540H inner sleeve is R22mm, the depth of the ball mouth is 3.26mm, and the process dimension between the inner diameter of the inner sleeve and the lowest point of the ball mouth is 23+0.2mm.
(3) Use a self centering three jaw chuck to clamp and fix the 53540H inner sleeve, select an end mill with a diameter of 44mm, install the end mill on the milling machine spindle and tighten it.
(4) Adjust the position of the milling cutter and the inner set ball mouth, conduct trial machining, and measure the relevant process dimensions of the ball mouth. When the process dimensions of the ball mouth meet the product process requirements, release the workpiece and make the unprocessed ball mouth end face upward. Process another ball mouth and make the two ball mouths 180 °.
(5) After processing an inner sleeve, release the clamp, remove the inner sleeve, and complete a work cycle. Replace another inner sleeve for the next working cycle.
2.2 Shortcomings
(1) Two auxiliary components (TS type rotary worktable and 300mm diameter self centering three jaw chuck) are needed to fix the inner sleeve, increasing the distance between the machined inner sleeve and the workpiece platform of the milling machine. The inner sleeve needs to be fixed through two connections, increasing system errors and instability factors.
(2) The positioning and clamping of the workpiece need to go through two layers of connectors and be completed manually. When the workpiece is subjected to cutting force, its positioning accuracy may be affected. When the clamping force is insufficient, the workpiece is prone to rotation, causing cutting and resulting in scrap; When the clamping force is too strong, it is easy to damage the inner and outer diameters of the workpiece, or cause deformation of the workpiece, resulting in waste products. (3) The two ball ports are 180 degrees apart, and the TS type rotary worktable needs to be rotated during processing, which extends the auxiliary working time.
3. Technical improvement of fixtures and boring machines
3.1 Technical improvement of fixtures
(1) Taking the processing of 53540H inner sleeve as an example, illustrate the improved design of the fixture. 53540H is a self-aligning roller bearing, and two ball mounting ports need to be machined to be 180 ° symmetrical on both ends of the inner sleeve. The boring machine processes the inner set ball mouth as shown in Figure 3.
(2) According to the characteristics of the boring machine, in order to save costs, the boring ball mouth fixture is designed as a multifunctional universal fixture, as shown in Figure 4. Firstly, design a positioning plate with adjustable diameters on the base, as shown in Figure 5. Draw a circle with a uniformly increasing radius centered on the center of the positioning plate, intersecting with three straight lines passing through the center and forming a 120 ° angle with each other. Drill holes of a certain diameter at each intersection point. According to the principle of determining a circle based on three points, the fixture is designed as an adjustable positioning plate with different diameters. One end of the positioning plate is arc-shaped and has a long hole groove. Design a positioning adjustment plate on the fixture base.
Figure 3 Boring machine processing inner set ball mouth
1. Inner sleeve 2. Opening pad 3. Pressure plate 4. Pull rod 5. Screw 6. Inner diameter positioning adjustment block 7. Ball port positioning block 8. Guide groove 9. Screw 10. Tension spring 11. Base
Figure 4 Multi functional universal fixture
(3) Drill M12 screw holes in three equal parts in the diameter direction of the fixture base. The difference in aperture between adjacent screw holes is 60mm, making it convenient to adjust different inner diameters. The pressure plate is a rectangular strip, and different lengths of pressure plates can be exchanged according to the diameter of the inner sleeve. A set of fixtures can process the ball mounting ports of different specifications of bearing inner sleeves, achieving universality of the fixtures.
(4) The positioning block of the ball loading port is designed to slide freely, relying on the tension of the tension spring to make the positioning block match the ball loading port, making it convenient to bore the second side of the ball loading port and ensuring that the ball loading ports on both ends are at a 180 ° angle. Remove this workpiece and proceed to the next work cycle.
(5) When processing a single ball loading port, remove the evenly distributed rotating ratchet of the boring machine.
(6) By relying on the ratchet mechanism to achieve uniform rotation and equal division, when the equal division fixture of the boring machine rotates 90 °, it can process the bearing inner sleeve end face into four equal oil grooves, increasing the equipment's functionality. By improving the fixture, the base is designed in three different structures according to the diameter of the inner sleeve being processed, and the way it is clamped on the rotating disc of the boring machine is also slightly different. Figure 4 shows one of the structures, while the other structures are omitted. One of the structures can process an inner sleeve with a maximum diameter of 560mm and an inner sleeve width of 260mm.
(7) When the boring machine speed is high, the frequency converter can be used to reduce the motor speed; When machining ball ports with a diameter within 280mm, alloy end mills can be used for processing.
3.2 Technical improvement of boring machine
Mainly improve the spindle of T9210 boring machine and produce new milling cutter fixtures. The original spindle taper was Mohs 5. According to the improvement requirements, the spindle of the boring machine has been redesigned and customized by the manufacturer. The inner diameter of the spindle tool magazine mouth has increased, and the depth of its taper hole has reached the unloading groove. Open two symmetrical 6mm key slots on the inner diameter of the spindle, and thread them onto the outer diameter of the spindle to secure the milling cutter fixture. Using a boring machine instead of a milling machine to process the ball mounting port of the inner sleeve allows products previously processed on the milling machine to be processed using a boring machine, making rational use of equipment and improving production efficiency.
3.2.1 Self made milling cutter fixture: Based on the actual modified process dimensions of the spindle, a 6mm symmetrical keyway is opened on the large end cone surface of the milling cutter fixture to facilitate key connection with the spindle. Using standard milling cutters, the Mohs taper of the inner hole of the self-made milling cutter fixture varies depending on the specifications of the milling cutter. The homemade milling cutter fixture can be pressed onto the boring machine spindle with a clamping nut. The improved milling cutter fixture is shown in Figure 6.
Figure 5 Fixture Base
(1) The outer diameter taper of the milling cutter magazine is Mohs 5, and the inner taper of the boring machine vertical shaft is Mohs 5. (2) The taper of the inner diameter of the tool magazine is taken as Mohs 2, Mohs 3, and Mohs 4 in order to be compatible with existing milling cutters and boring cutters. (3) When milling the ball mouth, the milling cutter is locally subjected to force and needs to be tightened with screws. (4) The nut is mainly used to prevent the milling cutter magazine from falling off the boring machine spindle.
4. Working principle
Fix the improved fixture on the equal fixtures of the boring machine, and adjust the inner or outer diameter on the same circumference according to the different inner or outer diameters of the product. Fix the inner sleeve of the ball mouth to be milled on the multifunctional fixture through the oil cylinder, pull rod, and pressure plate, and adjust the position of the ball mouth to be milled. Fix the self-made milling cutter fixture to the spindle of the boring machine, start the machine tool for small feed adjustment and processing, check the process dimensions of the processing part, and after multiple adjustments and processing, make sure that the process dimensions of the ball mouth meet the design requirements. Then replace the next product for further processing. The processing method is shown in Figure 3.
5. Improved advantages
(1) Cancelling the two intermediate transition connections eliminates the system errors and unstable factors caused by multiple connections. (2) By using hydraulic cylinders, pull rods, and pressure plates, the processed products can be firmly compressed to prevent loosening of the inner sleeve, eliminate inner diameter clamping and deformation, and ensure the stability of product quality. (3) By relying on hydraulic devices to fix products, clamping products is convenient and fast, improving processing automation and reducing labor intensity. (4) Expand the processing range of the boring machine, with a maximum outer diameter of 560mm for the inner sleeve and a height of 260mm for the inner sleeve. (5) The milling cutter fixture can be equipped with a universal milling cutter or a self-made single blade or double-edged boring cutter, and the length of the cutter can be determined according to the needs. (6) The boring machine has stable and reliable performance, and the feed rate, feed speed, and stroke of the boring machine can be adjusted according to the processing volume of the product. Adjust appropriately, you can feed or retract the knife by yourself, reduce intermediate auxiliary time, and improve production efficiency.
1. Milling cutter 2. Lock nut 3. Milling cutter magazine 4. Key 5. Boring machine spindle 6. Screw
Figure 6 Improved milling cutter fixture
6. Conclusion
Through trial operation and successful trial production, the processed product meets the design requirements, reduces labor intensity, shortens processing cycle, improves production efficiency, and expands product processing range. This improvement has achieved the expected results and brought good economic benefits to the company.
2025 August 1st Week VAFEM Product Recommendation
VAFEM single bearings, manufactured to original equipment quality, are assembled in Langenbach, along with all the necessary components. There are four different models: grooved and angular roller bearings,tapered roller bearings,integrated wheel bearing units (hub units with built-in electronic sensors), and the bearings used for ABS, TCS, CPWM and navigation systems. In VAFEM catalogue you will also find images of each individual item. Our range of wheel hubs has also been considerably extended.
2025-08-08