1. Home
  2. Product Information
  3. Linear Actuator
  4. Model KR The Integrated Linear Actuator

Model KR
The Integrated Linear Actuator

Because of its inner block with an integrated structure consisting of a highly rigid outer rail with a U-shaped cross section, LM Guide units on both side faces, and a ball screw unit in the center, the Model KR LM Guide Actuator enables a highly rigid and highly accurate linear actuator in a minimal space.
In addition, since the housings A and B also serve as support units and the inner block functions as a table, this model allows significant reduction of design and assembly time, thus contributing to overall cost savings.

Model KR
KR Linear Actuator

This General KR catalog presents the complete lineup of KR linear actuator sizes.

Quck-Ship KR Linear Actuator

THK America's Quick Ship program enables rapid delivery of commonly-sized KR linear actuators, with shipping timeframes of 2 days to 2 weeks depending on current stock levels.

Semi-Custom KR/SKR Linear Actuator

The Semi-Custom Series features model number designations for customization such as surface treatment, positioning pins, etc., that are commonly required in specific markets and applications.

KR-R/L Right-Left Handed Screw

This unit converts shaft rotation into linear opening/closing motion using right-hand and left-hand threads on a single shaft. It is used in gripping and centering devices, leveraging the KR series' compact design and high rigidity.

Customized KR

THK flexibly accommodate customizing requests to your meet needs such as
・Non-standard lengths
・High-Thrust Type
・Custom motor mounting brackets, etc.
Please contact with THK via Chat, local contact, distributors.

Tools

Designer

Model KR

2D/3D CAD

Model KR Download 2D&3D-CAD

Life Calculator

Model KR

Features

Structure and Features

Because of its integral-structure inner block consisting of a highly rigid outer rail with a U-shaped cross section, LM Guide units on both side faces and a Ball Screw unit in the center, LM Guide Actuator model KR achieves a highly rigid and highly accurate Linear actuator in a minimal space. In addition, since the housings A and B also serve as support units and the inner block as a table, this model allows significant reduction of man-hours required for design and assembly, thus contributing to total cost cutting.

4-way Equal Load

Each row of balls is arranged at a contact angle of 45° so that the rated load on the inner block is uniform under loads applied to the inner block in the four directions (radial, reverse radial and lateral directions). As a result, model KR can be used in any mounting orientation.

High Rigidity

Use of an outer rail with a U-shaped cross section increases the rigidity against a moment and torsion.

Table1 Cross-sectional Characteristics of the Outer Rail

Model No.

IX[mm4]

IY[mm4]

Mass[kg/m]

KR15

9.08 × 102

1.42 × 104

1.04

KR20

6.1 × 103

6.2 × 104

2.6

KR26

1.7 × 104

1.5 × 105

3.9

KR30H

2.7 × 104

2.8 × 105

5.0

KR33

6.2 × 104

3.8 × 105

6.6

KR45H

8.4 × 104

8.9 × 105

9.0

KR46

2.4 × 105

1.5 × 106

12.6

KR55

2.2 × 105

2.3 × 106

15.0

KR65

4.6 × 105

5.9 × 106

23.1

lX =geometrical moment of inertia around X axis
lY =geometrical moment of inertia around Y axis

High Accuracy

Since the linear guide section consists of 4rows of circular-arc grooves that enable balls to smoothly move even under a preload, a highly rigid guide with no clearance is achieved. Additionally, variation in frictional resistance caused by load fluctuation is minimized, allowing the system to follow highly accurate feed.

Space Saving

Use of a inner block integrating LM Guide units on both ends and a Ball Screw unit in the center makes model KR a highly rigid and highly accurate linear actuator in a minimal space.

Seal

Model KR is equipped with end seals and side seals for dust prevention as standard.

Table2 shows the rolling resistance and seal resistance per inner block (guide section).

Table2 Maximum Resistance Value
Unit: N

Model No.

Rolling resistance value

Seal resistance value

Total

KR15

0.2

0.7

0.9

KR20

0.5

0.7

1.2

KR26

0.6

0.8

1.4

KR30H

1.5

2.0

3.5

KR33

1.5

1.9

3.4

KR45H

2.5

2.6

5.1

KR46

2.5

2.5

5

KR55

5.0

3.8

8.8

KR65

6.0

4.1

10.1

Note) The rolling resistance represents the value when a lubricant is not used.