Analysis of the Linear Motion Guide series of THK

THK is recognized as a pioneer in the first practical application of linear motion guides. They offer a wide range of linear motion carriage products, including caged ball type, caged roller type, full complement roller type, and full complement ball type, to meet the needs of high-precision, high-rigidity, energy-saving, and high-speed machinery.

Tips: The series descriptions in this blog have been compiled based on the official product catalogs and authoritative online sources. Some models are not included due to little information. Thank you for your understanding.

Cage Ball Linear Motion Guide Series (SHS, SSR, SHW, SRS, SCR, EPF, SVR/SVS)

Key Design Features :
Uses balls as rolling elements and is equipped with a ball cage. The cage eliminates friction between the balls, resulting in low noise, good running sound, long-term maintenance-free operation, and excellent high-speed responsiveness.

Main Recommended Applications :
General-purpose applications requiring smooth, quiet, high-speed and low-maintenance linear motion. Specific applications vary by sub-series.

SHS Series (Global Standard Size, Cage Ball Type)

Design :
Global standard size, four-way equal load (45° contact angle), self-aligning capability (DF combination), heavy load capacity, high precision, and long-term maintenance-free design. Optional narrow version and threaded hole (SHS-V/VM, SHS-R/RM). Stainless steel option available. Sizes: 15–65.

Applications :
Widely used due to its global standard dimensions and four-way equal load characteristics. Suitable for various machinery requiring high precision and smooth motion, including machine tools and industrial automation. SHS-R/RM inherits the height dimension of HSR-R. Used for large automatic glass doors where conventional rollers failed.

The SHS series has global standard dimensions, a 45° contact angle to achieve equal load distribution in four directions, self-aligning capability, high precision, smooth motion, and long-term maintenance-free performance. One application case is for large automatic glass doors, solving the situation where conventional resin rollers cannot be used due to door weight increase and wind pressure problems.

SSR Series (Radial Type, Ball Type with Cage)

Design :
Compact design, low cross-section height, ball contact structure at 90° in the radial direction. Self-aligning capability (DF combination), high precision, long-term maintenance-free. Stainless steel option available. Size: 15–35.

Application :
Best suited for horizontal guide units due to its radial load design and low profile. Provides excellent plane running accuracy.

The SSR series adopts a radial contact structure, low cross-section height, and compact design, which is particularly suitable for horizontal rail applications and can provide excellent planar running accuracy.

SHW Series (Wide Rail Type, Cage Ball Type)

Design :
The LM guide rail structure is wide and the center of gravity is low, so this four-way equal load LM guide rail can achieve high torsional rigidity. Self-aligning capability (DF combination), high precision, long-term maintenance-free. Suitable for monorail use. Low dust generation. Size: 12–50.

Application :
Best suitable for occasions requiring space saving and large Mc torque rigidity, suitable for monorail applications.

The SHW series adopts a wide LM guide rail and low center of gravity design, which is very suitable for occasions requiring space saving and large Mc torque rigidity, and is also suitable for monorail use.

SRS Series (Miniature, Cage Ball Type)

Design :
Miniature, four-way equal load, high precision, long-term maintenance-free. Standard stainless steel material (LM guide rail, LM block, and ball). SRS-S is the short block version. Size: 7–15.

Application :
Suitable for compact and precision applications where space is limited and maintenance needs to be minimized, such as medical equipment, semiconductor equipment, or small robots (inferred from the characteristics of miniature and stainless steel).

The SRS series is a miniature design with stainless steel as standard, featuring four-way equal load and high precision, suitable for compact precision equipment.

SCR Series (Cross LM Guide, Cage Ball Type)

Design :
Orthogonal LM system, X-Y motion without saddle. Monoblock type based on the internal structure of SHS, using two LM guides in combination. Four-way equal load, high rigidity (higher than two conventional blocks bolted back-to-back), long-term maintenance-free, high precision. Size: 15–65.

Application :
Best suited for building X-Y tables that require high rigidity and simplified structure (no saddle required, which can reduce the overall system size).

The SCR series is an orthogonal LM system that achieves X-Y motion without a saddle by combining two LM guides, simplifying the structure and improving rigidity.

EPF Series (Limited Stroke, Ball Type with Cage)

Design :
Miniature, limited stroke model. Low friction, four-way equal load, high precision, long-term maintenance-free. Standard stainless steel construction. Size: 7–15.

Application :
Suitable for applications that require precise linear motion within a limited stroke, such as precision positioning stages, small robot end effectors, medical or optical equipment (inferred from the characteristics).

The EPF series is a miniature guide designed for limited stroke, offering low friction and high precision, constructed from stainless steel.

Caged Roller Linear Motion Guide Series (SRG, SRN, SRW)

Key Design Features :
Rollers as rolling elements with roller cages. Ultra-high rigidity, low friction, smooth motion and long-term maintenance-free operation.

Main Recommended Applications :
Heavy-duty applications requiring extremely high rigidity and smooth operation, such as machine tools.

SRG Series (Ultra-High Rigidity, Caged Roller Type)

Design :
Ultra-heavy-duty roller linear motion guides with twice the rigidity of full-complement ball-type linear motion guides. Global standard dimensions (similar to HSR). Equal load in four directions (45° contact angle). Total roller length greater than 1.5 times the diameter. Smooth motion with roller cages to prevent deflection. Long-term maintenance-free. Sizes: 15–100.

Applications :
Heavy-duty machine tools, industrial robots, semiconductor manufacturing, large automation systems and other applications requiring the highest rigidity and load capacity.

The SRG series achieves ultra-high rigidity and ultra-heavy load capacity by adopting high-rigidity rollers and roller cages, and its dimensions are almost the same as the HSR global standard model.

SRN Series (Ultra-High Rigidity, Low Profile, Roller Type with Cage)

Design :
Lower overall height than SRG, suitable for compact design. Ultra-high rigidity (roller length greater than 1.5 times the diameter). Equal load in four directions (45° contact angle). Smooth movement by preventing deflection. Long-term maintenance-free. Sizes: 35, 45, 55, 65.

Application :
Machine tools that require high rigidity in a compact space.

The SRN series has a lower profile than SRG while maintaining ultra-high rigidity, suitable for compact design, especially in machine tool applications.

SRW Series (Ultra-High Rigidity, Wide Type, Roller Type with Cage)

Design :
Based on SRG, but with wider LM guide rail and two rows of LM guide mounting holes for high mounting strength and stability. Structurally well resistant to moments in the Mc direction. Ultra-high rigidity (roller length greater than 1.5 times diameter). Smooth motion by preventing deflection. Long-term maintenance-free. Sizes: 70, 85, 100, 130, 150.

Application :
Applications requiring very high rigidity, heavy support, resistance to moment loads, and stable, smooth motion, such as large machine tools or industrial equipment.

The SRW series is based on SRG, but with wider LM guide and two rows of mounting holes for significantly improved mounting strength and stability, especially against moment loads in the rolling direction.

LM Guide (Full Roller Type) Series (HRX)

Key Design Features :
Full complement of rollers (no cage) for higher rigidity. Equal load in four directions (45° contact angle). Ultra-high rigidity, high precision, heavy/very heavy load. Sizes: 25–65.

Main Recommended Applications :
Demands requiring maximum rigidity and load capacity, where the benefits of the cage (noise reduction, speed) are secondary considerations. The HRX-LR variant has a smaller width for compact designs.

Technical Advantages :
The HRX series uses a full-roller design without a cage, achieving higher rigidity than roller-type linear motion guides with cages, and is suitable for occasions with extremely heavy loads and high precision requirements.

LM Guide (Full Complement Type) Series (HSR, HDR, SR, etc.)

Key Design Features :
Full complement of balls (no cage). Available in sizes ranging from miniature to large-scale for machine tools and linear or curved motion applications.

Main Recommended Applications :
Broad application range, including general-purpose machine tools. Specific suitability depends on the individual series within this category.

HSR Series (Global Standard Size, Full Complement Type)

Design :
Global standard dimensions, four-direction equal load distribution (45° contact angle), self-aligning capability (DF combination), high rigidity, high durability. Stainless steel option available. A stopper retains the ball (not applicable to small sizes). Sizes: 8–150.

Applications :
Suitable for a wide variety of directions and applications due to its four-direction equal load characteristics and self-aligning capability. Commonly used in industrial machinery, automation equipment, and precision systems.

As a global standard model, the HSR series uses a 45° contact angle to achieve balanced loading across four directions and incorporates THK’s unique arc groove design (DF combination) to provide self-aligning functionality, enabling it to absorb installation errors and support high-precision, smooth motion.

LM Guide with Cage Ball Model SPR/SPS

Key Design Features :
Caged ball type. Achieves ultra-low fluctuation comparable to hydrostatic guides. Provides ultra-high rigidity that exceeds roller-type guides by minimizing ball deformation.

Main Recommended Applications :
Applications requiring extremely high rigidity, precision, and ultra-smooth motion, where performance may be comparable to hydrostatic guides.

The SPR/SPS series achieves ultra-low fluctuation comparable to hydrostatic guides and ultra-high rigidity surpassing roller-type linear motion guides by minimizing ball deformation.

Conclusion

As a pioneer of linear motion guides, THK’s “Global Standard Model HSR” demonstrates its strong influence on market standards. The company’s extensive product lineup incorporates cage technology , highlighting a strategic emphasis on advantages such as low noise, high speed, and long-term maintenance-free operation.

THK offers comprehensive solutions from miniature linear motion guides to ultra-heavy load/ultra-high rigidity applications , including specialized designs such as crossed linear motion guides and wide rail linear motion guides , meeting a broad spectrum of industrial requirements.

The SPR/SPS series represents THK’s efforts to combine the benefits of traditional guide technologies—static stability (as seen in hydrostatic systems) with high rolling element rigidity —achieving ultra-smooth motion and ultra-high rigidity that surpasses conventional roller-type linear motion guides.