*Reliability Technology Based on Meta-Action for CNC Machine Tool DOI: http://dx.doi.org/10.5772/intechopen.85163*

**Figure 3.** *Worm rotating MU.*

output, middleware, support, and fastener. The specific definition of each basic

In order to describe the concept of MU, a conceptual MU model is established,

The structural model describes the MU from the aspect of mechanical structure. In general, two types of MUs units are moving units and rotating units. **Figure 3** is

action unit

action unit

worm

gaskets, etc.

In worm and worm gear drive, the motor is the input of the element action unit, which provides the power input for the element

In worm-worm gear transmission, the worm is the output of the element action unit in which it is located, and motion and power are transmitted to the input of the next element's

In worm and worm gear transmission, the coupling transmits the motion and the power output by the motor to the output of the unit -

Such as screws, pins and end covers, spring washers, sealing rings, sealing sleeves, sealing

Such as bearing, piston cylinder, sleeve,

machine tool base and box

**Definition Example**

In MU, the parts that receive or provide a power source or adjacent to the motion or power input of the previous MU

The last part of a MU that outputs motion or power is the main part of the MU and it completes the specified meta-action

between a "power input" and a "power output" and plays a major role in transmitting motion and power, and has no relative motion

sealed, or is used to connect two or more parts

A part in a MU that provides assembly references or supporting functions for other

with the input and output parts

Fastener In a MU, a part that is fixed, loosen-proof, and

Middleware A part (part combination) that occurs

without relative motion

parts

*The definitions of MU basic elements.*

element is shown in **Table 1**.

*3.2.3 The basic model of MU*

which is shown in **Figure 2**.

**Composed element**

Power input parts

Power output parts

Supporting parts

**Table 1.**

**Figure 2.**

**52**

*The conceptual MU model.*

1. The conceptual model of MU

*Reliability and Maintenance - An Overview of Cases*

2. The structural model of a MU

**Figure 4.** *Pallet moving MU.*

the structural model of typical rotating units. **Figure 4** is the structural model of typical moving units.
