Design of Auxiliary Ball Loading Device for Sealed Full Load Ball Bearings

Abstract: Analyzing the structural performance and ball loading process characteristics of sealed full ball bearings, an auxiliary ball loading device was designed, which adopts semi-automatic operation and improves assembly efficiency by more than twice.

Keywords: rolling bearings; seal up; Fully loaded; Ball loading; Assembly accessories

Full load ball bearings improve the bearing capacity by increasing the number of steel balls inside the bearing, while retaining the characteristic that ball bearings are suitable for high-speed rotation. They are suitable for high-speed swinging and high load situations, such as applications in textile equipment opening devices. The structure of a sealed fully loaded ball bearing is shown in Figure 1. The raceway of this type of bearing is filled with steel balls and does not have isolation elements such as retainers. It is often a double-sided sealed structure. There is a gap of appropriate depth in the axial direction of the outer ring of the bearing, but the gap does not extend to the bottom of the raceway. The design of the gap ensures the integrity of the raceway during the machining process and provides convenience for filling balls during assembly.

Figure 1 Schematic diagram of sealed fully loaded ball bearing structure

The assembly of fully loaded ball bearings is usually carried out in two steps: (1) extruding the outer ring to "break" along the notch, which is called "clamping"; (2) Choose a suitable matching inner ring, use fixtures to expand and deform the outer ring, and at the same time fill the steel balls into the inner and outer ring raceways. The traditional assembly method is inefficient, and both clamping and expansion rely on manual labor, which is labor-intensive. At the same time, manual operation cannot accurately control the amount of deformation, and there is a quality risk that the ring cannot be restored to its original state after deformation.

The auxiliary ball loading device designed is shown in Figure 2. The clamping and expansion deformation of the outer ring during assembly are all completed by the cylinder. By adjusting the installation position of the cylinder on the bottom plate to control the expansion and contraction of the cylinder, the deformation of the ring is effectively controlled, while greatly reducing the labor intensity of manual labor. The device uses a PLC control program to achieve the following actions through a foot pedal device: clamp off the cylinder to squeeze the outer ring → clamp off the cylinder to retract (deform the cylinder while squeezing the ball support plate to open it) → deform the cylinder to retract (merge the ball support plates at the same time). The simultaneous action of the cylinder is due to the spatial position between the cylinder and the ball disc, and the combined action of the sliding pin and spring causes the deformed cylinder to retract and the ball disc to merge simultaneously.

1- Deformable cylinder connecting plate; 2- Top pole; 3- Sliding sleeve; 4- Cylindrical pin; 5- Pad; 6- Sliding pin; 7- Sliding pin seat; 8- Ball tray; 9- Top block; 10- Spring; 11- Ball bearing outer ring; 12- Bottom plate; 13- Clamp off the cylinder connection plate; 14- Pinch off the cylinder; 15- Deformable cylinder

Figure 2 Schematic diagram of auxiliary ball loading device structure

When installing the ball, first place the fitted inner and outer rings on the ball tray, press the foot trigger switch to clamp off the cylinder connecting rod and break the outer ring, then press the foot trigger switch again to clamp off the cylinder connecting rod and retract it. The deformed cylinder connecting rod is squeezed towards the ball tray, and the ball tray opens with the outer ring. After installing the steel ball into the inner and outer ring raceways, press the foot trigger switch again to retract the deformed cylinder, merge the ball trays, and restore the elastic deformation of the outer ring. The entire ball installation process is completed. The key part of the ball loading mechanism lies in the design of the ball bearing disc. After the ball bearing disc is processed as a whole, it is cut into two equal halves by wire cutting. One side of the ball bearing disc is designed with an inclined stopper. After placing the outer ring on the ball bearing disc, the stopper extends into the outer ring sealing groove. The bearing outer ring is integrated with the ball bearing disc when compressed and opened, and its radial and axial degrees of freedom are respectively limited, solving the problems of slip and jumping that may occur in the outer ring during assembly.

Through production inspection, the ball loading device has been well applied in steel ball assembly production, greatly improving the efficiency of ball loading. The original manual assembly team produced 3000 pieces, which increased to over 6000 pieces, and the product quality after assembly is stable and reliable.

2024 July 3rd Week KYOCM Product Recommendation:

Slewing Bearing ：

Rotary bearings consist of an inner ring and an outer ring, one of which usually contains a gear. Together with the connecting holes in the two rings, they enable optimized power transmission through simple and fast connections between adjacent machine parts. Bearing raceways are designed with rolling elements, cages or gaskets to accommodate loads acting individually or in combination in any direction.

Features and advantages:

High carrying capacity

High stiffness for rigid bearing applications

Low friction

Long service life

Surface protection and corrosion resistance

Integrate other features including:

Driving mechanism

Control device

Lubrication system

Monitoring system

Sealed cassette tape

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