The Constitution of a Linear Guideway

Figure 1: A Happybuy linear guideway.

The linear guideway, also called the linear guide, is used for high-precision or high-speed linear reciprocating motion. It can bear a certain torque and can achieve high-precision linear motion under high load. For steel balls, there are both balls as load-bearing elements and rollers as load-bearing elements inside the bearing.
The linear guideway is mainly composed of a guide rail, a slider, balls, an end cap, a dust cover, and planes and datum planes. This article will give a brief introduction on these components.

1. The Guide Rail

A rail is an elongated element, usually fixed on a datum plane. A series of screw mounting holes are installed on the rail for mounting screws. Different guide rail lengths can be selected according to the required motion stroke, with a maximum length of 4m.
The manufacturer can cut the length of the guide rail according to the user's requirements. Due to the use of special materials, professional processing equipment and technology for manufacturing, the guide rail has excellent performance and excellent precision.

2. The Slider

The slider is a rectangular section on which two or four screws are mounted to fit the threaded holes. It also has a precision machined mounting surface for mounting loads (i.e., various actuators). According to the use conditions such as load shape, size, eccentricity, etc., one, two or three sliders can be selected to be used with the guide rail.
Note: the linear guide mechanism is a precision part. The manufacturer inspects and adjusts the slider when it leaves the factory. It cannot be removed during transport, storage and installation. If it is really necessary to remove the slider, the manufacturer needs to seek support to take special measures, or the accuracy of the mechanism will be sabotaged or even the parts will be damaged.

Figure 2: The components of a linear guideway.

3. The Ball

Inside the slider, there is a series of steel balls, one set on one side, and two sets in total. The balls contact the slider and the guide, respectively. The movement of the slider relative to the guide rail depends on the continuous rolling of the balls. Loads (pressure and possible torque) are first transferred to the slider, then through the balls to the rail, and finally to the base mounting surface. Balls play an important role in the transmission and bearing of the mechanism.

4. The End Cap

The end cap is a fixed ball so that the other balls can form a ring.

5. The Dust Cover

The dust cover is a protection part. The linear guideway is a precision part and does not allow the pollution of dust. And the role of the dust cover is dust proof to ensure the precision of the whole mechanism.

6. The Mounting Plane and the Mounting Datum Plane

Figure 3: A sectional view of a linear guideway.

The linear guide mechanism has four important planes in use: two mounting planes and two mounting datum planes. The two mounting planes refer to the upper plane of the slider and the lower plane of the guide rail, which are used to install the load (such as a workbench) and fix the guide rail, respectively. The two mounting datum planes are used to determine the direction and guide of the load.
During the assembly process, in order to facilitate the identification of the assembly datum, the manufacturer has marked a special symbol on the assembly datum. All four planes are precisely ground during the manufacturing process, and the correct installation of the machine allows the loads to move in a straight line with stability and precision.

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