Complete solutions for linear motion - linear units, linear modules and linear actuators

Mechanical components for linear motion can be found in various industrial applications. They are an important component of many machines or systems and fulfill a wide variety of tasks in these. The requirements for the components used are as varied as the application in which the linear movement occurs and into which the solution is to be integrated.

Is there a complete solution for linear motion?

Do loads need to be moved in a straight path? Does the application require high precision positioning or controlled lifting movements? And what repeatability is required? Each of these requirements may require linear motion, and different components may be considered for linear motion depending on which center of gravity is placed. In order to realize linear movements and to meet the respective requirements, several coordinated components must be combined to form a complete solution integrated into the system.

Learn more about linear motion components in this blog.

But is there a complete solution for linear motion?

There is no simple answer to this question.

A complete solution for the linear motion required in a machine or system is strictly defined by the interaction of all parts involved in the machine or system. These include linear motors, linear actuators, screw drives, linear guides, and various other components that permit linear motion.

If one considers each of these components in isolation, they only represent a partial solution that has a range of characteristics such as precision, travel speed, torsional stiffness, etc. For example, although a ball screw is delivered with a lead screw and ball nut, it additionally requires precise supports such as bearing blocks and a driver to perform its task.

Although it is unusual to find a complete solution for all linear motion, linear units, linear modules or actuators are available for certain applications, some of which we will review now.

KU series: Linear units with 2 external profile rail guides and ball screw

KU series single-axis linear units are mechanically fully-operational units with a combined profile rail guides and ball screws. KU Series linear units are ideal for positioning heavy loads. Models are available with rolled and precision ground ball screws, as well as sealed models.

The KU Series uses rolled screw drives of accuracy class C10 (JIS B 1192) or precision screw drives of accuracy class C5 (JIS B 1192). Ball screw diameter and pitch are selectable. KU Series single-axis units are equipped with a motor installation interface for easy mounting of suitable motors.

Single-axis units: standard

• Rolled drive: KUA with servo motor / KUB with stepper motor
• Ground drive: KUH with servo motor / KUT with stepper motor

Single axis units: sealed

• Rolled drive: KUAC with servo motor / KUBC with stepper motor
• Ground drive: KUHC with servo motor / KUTC with stepper motor

For more information on motor interface dimensions such as NEMA23 or NEMA34, possible couplings, accuracy, static load capacity, and matching motors, see this PDF for standard units and this PDF for sealed single-axis units.

See the PDF Single-axis Linear Unit Options for information on matching sensor sets. For KUA and KUB rolled ball screws, it is also possible to adjust the shaft end of the fixed bearing side. For more information, see this PDF.

Furthermore, KU Series linear units are also used as manually operated units (KUL, KULF and KULDP) for lift tables.

LX Series: Linear module with integrated internal rolling guides and ball screw

LX Series single-axis linear units offer high rigidity, high accuracy and compact design. These ball screw linear units with profile rail guide are compatible with a variety of motors for low noise and high-accuracy operation with repeatability of ±5μm (precision grade ±3μm).

MISUMI LX units are available in 5 sizes with a maximum stroke of 151.9 mm to 497.9 mm, depending on the type. Some LX linear units can also be equipped with 2 guide carriages.

LX units can be ordered with an MX lubrication unit that provides long-term maintenance-free operation. However, this option is only available for models with a guide carriage. To mount a servo motor or stepper motor to the motor mount, different motor adapter plates and couplings (PDF compatibility table) are required depending on the series and the selected motor. These can be easily aligned and mounted with the help of a suitable motor adapter centering tool.

All LX units are available in standard and sealed versions. The LX30 and LX45 also have the option to select a motor mount for a parallel axis drive (folded version).

RS series: Linear modules with internal linear guides and actuator or belt drive

The RS Series is a linear unit already equipped with a matching drive. These linear units, also called single-axis robots, are available with ball screw, belt drive or compact rod design. For additional servo motor specifications, see the PDF RS Servo Motor Specifications and the PDF RS Stepper Motor Specifications for use with a stepper motor

RS Series with Ball Screw Drive and Carriage:

The RS1, RS2 and RS3 models are particularly small and economical with a load capacity of up to 12kg (horizontal) and up to 4kg (vertical). Up to 80kg (horizontal) and up to 20kg (vertical) load capacity can be moved by the RSH1, RSH2, RSH3, RSH4 and RSH5 models, and RSF4 models have a wider design.

Example for models RS1, RS2, and RS3 with cross-sectional sketch: (1) carriage, (2) ball screw drive, (3) high-quality stainless steel plate, (4) guide rail, (5) example with stepper motor (position sensor: rotary encoder), (6) double limit switch, 4-point circular arc raceway guide.

Example for models RSH1, RSH2, RSH3, RSH4, and RSH5 with cross-sectional sketch: (1) carriage, (2) ball screw drive, (3) and (4) guide rails, (5) example with AC servo motor (position sensor: rotary encoder), (6) double limit switch, 4-point circular arc raceway guide.

Example for model RSF4 with cross-sectional sketch: (1) carriage, (2) ball screw drive, (3) and (4) guide rails, (5) example with AC servo motor (position sensor: rotary encoder), (6) double limit switch, 4-point circular arc raceway guide.

RS Series with ball screw drive and piston rod:

The RSD1, RSD2, and RSD3 models are equipped with a piston/rod instead of a carriage. They are available in load capacities up to 60kg (horizontal) and 30kg (vertical). The RSDG1, RSDG2, and RSDG3 models are also equipped with a support guide.

Example for model RSDG1 with cross-sectional sketch: (1) coated contact scraper – prevents foreign particles from entering the housing, (2) lubrication system, (3) example with stepper motor (position sensor: rotary encoder), (4) guide with 4-point circular arc raceway.

RS Series with belt drive and carriage:

The RSB1 and RSB2 models are also equipped with a carriage. However, the carriage position is controlled by a belt drive, which allows high-speed position changes. They have a medium load capacity with a load capacity of up to 20kg (horizontal).

Example for models RSB1 and RSB2 with cross-sectional sketch: (1) carriage, (2) belt, (3) and (4) guide rails, (5) example with AC servo motor (position sensor: rotary encoder), (6) double limit switch, 4-point circular arc raceway guide.

All models are supplied as a complete set with control interface, controller, cable, and software (where applicable). Additional handheld control interfaces are also available as an option.

The RS-Series allows for easy multi-axis machining by daisy-chaining multiple controllers. The parameters of the control units from several PCs can be processed on one PC by simply switching between the station addresses in the RS Manager screen. A connection can be established with up to 16 control units.

Find more information on linear motion in our blogs about profile rail guides and linear guide systems.

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