## 4.4 Ball Joints

The transmitting elements in ball joints are balls which run independently along guide tracks. It is assumed that the compressive force P is evenly distributed among all m-active balls. This number of balls m depends on whether the joint is divided according to the Rzeppa principle (concentrically) or the Weiss principle (radially), see Fig. 4.26.

1. Rzeppa type m = z,

2. Weiss type m= z/2

Fig. 4.26: Number of active balls m in joints with z balls.

The dividing planes between the input and output members are then either con-centric with (Fig. 4.26a) or radial to the longitudinal axis of the joint (Fig. 4.26b). In the Rzeppa arrangement, all the balls act for each direction of rotation whereas with the Weiss arrangement only half the balls act. In the universal torque equation for joints (4.16), for the Rzeppa arrangement m = z, and for the Weiss arrangement m = z/2.

In addition to the way in which the planes run relative to the longitudinal axis of the joint, the shape of the tracks in this direction is also critical; this is the "effective geometry" in Sects. 2.3.1 and 2.3.2.

Where there are curved tracks the joint can only articulate, there can be no plunging. Straight and helical tracks allow articulation and plunge of the joint. Ball joints can therefore be further categorised as fixed joints and plunging joints.

### 4.4.1 Static and Dynamic Torque Capacity

As...

##### Products & Services
Ceramic Balls
Ceramic balls are spherical, rolling elements that provide higher stiffness, lower thermal expansion, lighter weight, increased corrosion resistance, and higher electrical resistance than steel balls. They are made from a variety of ceramic materials.
Swivel Joints
Swivel joints are used in fluid and pneumatic systems that require torsional rotation between flow lines.
Radial ball bearings are friction reduction, rotation devices that carry loads radially around its axis. A subtype of ball bearings, they operate through the use of lubricated steel balls placed between two circular guides. They are frequently called deep-groove bearings.
Ball Joints
Ball joints are flexible joints consisting of a ball with a protruding stud that has been captured inside an outer housing. They allow simultaneous limited motion in all directions, including rotation as well as angular.
Universal Joints
Universal joints are flexible mechanical connections used to transmit rotary motion from one shaft to another shaft that is not in line with the first, or when alignment varies during service.

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