THK LM Guides

THK's creative ideas and unique technology made the company worldwide pioneers in the development of the Linear Motion (LM) Guide mechanism. Today, the LM Guide is an indispensable component of mechanical and electronic systems in a wide variety of industries whether it is Machining centres and grinding machines used by the Machine tool industry or an X-Ray machine and MRI used in the Medical field. The THK LM Guide is used everywhere from huge skyscrapers for earthquake protection to positioning in optical instruments; used in creating Megastructures and Nano ICs.

Caged Ball Technology
High levels of noise, short service life and the inability of usage at high rotating speeds led to the development of the ball cage in ball bearings. These ball bearings with cage were able to demonstrate long service life despite the number of balls being fewer than packed ball types, and evolved significantly so that they were able to be used in a wide range of applications.
THK has developed a similar technology for the LM Guide called the Caged Ball Technology and Caged Roller Technology where the balls don’t touch each other but are separated by the cage structure which keeps the balls aligned.

Features of Caged Ball Technology

Quiet Operation - Interference noise between balls is eliminated by the ball cage resulting in quiet operation.
Orderly Ball Movement - Balls are held by the cage in the form of a belt. They are aligned uniformly and move in a circulating manner. There is no skewing of the balls, while sudden variations in friction are also eliminated.
Excellent High-Speed Performance - The use of ball cages eliminates generation of heat caused by friction between balls resulting in excellent high-speed performance.
Grease Holding Structure - Grease pockets are provided consecutively over the entire ball circulating path to constantly lubricate the balls enabling long-term, maintenance-free operation and Long Service Life.

Types of Guides
THK has developed a variety of LM Guides to satisfy the various applications and scenarios under which they are used. But they can be broadly classified into Caged Ball and Caged Roller type, Full Ball type and Cross Roller Type LM Guides.

Caged Ball and Caged Roller Guide
SHS (HSR)	Global Standard Size (almost the same as THK’s HSR type)· Can be used in all orientations Low CG,High Rigidity Similar to Full Ball type HSR	SSR (SR)	Radial type Optimal for Horizontal use · Stainless steel type available as Standard Similar to Full Ball type SR
SNS (NRS)	Ultra Heavy load LM Guide Radial type (horizontal usage) Similar to Full Ball type NRS	SNR (NR)	Ultra Heavy load LM Guide 4 way equal load type Similar to Full Ball type NR
SHW (HRW)	Wide Rail Low CG Large Rolling Moment Rigidity Similar to Full Ball type HRW	SRS (RSR)	Miniature Type Model Lightweight and Compact· Similar to Full Ball type RSR
SCR (CSR)	Orthogonal LM system model Single block connecting X Y rails eliminates need of saddle Similar to Full Ball type CSR	SRG	Caged Roller Guide with Ultra High Rigidity Global standard dimensions Dimensions similar to HSR type
SRN	Caged Roller guide Low CG (low sectional height) Ultra-high Rigidity	SRW	Caged Roller Guide Wide Rail with high Mc moment Ultra-high Rigidity
Full Ball Guide
Apart from the Full Ball type guides mentioned above along with their Caged Ball equivalents, following are the other unique models created by THK
RSR RSRW RSH RSHZ	Miniature Type Model Ultra compact RSH - With Ball Retainer Z - Some parts made of resin	HR	Separate type 4 way equal load model with parallel installation of 2 rails Low sectional height
GSR	Separate type Radial Model Optimal for locations where it is difficult to secure mounting accuracy	GSRR	Integrated Rack Model Easy to design systems with pinion shaft bearings and tables that are not rigid
HCR	Circular Motion Rail model Allows circular motion of 5m or longer (unlike swivel bearings)	HMG	Straight-curved guide model Same type of LM blocks move on straight and curved rails
NSR-TBC	Self Aligning Type· Permits rough installation	JR	Structural Member Rail Model Can be mounted even under rough conditions
MX	Miniature Orthogonal system Single block connecting X Y rails eliminates need of saddle· Makes the XY system ultra compact	M1 M2	M1 – LM Guide with maximum service temperature of 150° C· M2 – LM Guide made with high corrosion resistive material (stainless steel resin materials)
Cross Roller Guide
VR	Orthogonally aligned precision rollers combined with a dedicated rail having a raceway cut into a V shaped groove, make the Cross Roller Guide Achieves a large effective contact length of the rollers and a short roller pitch interval It is a highly rigid type	VB	Finite LM system having precision steel balls arranged in short pitches in ball cage combined with V rail model High Corrosion Resistance Long Life (6 times more than conventional type) Safe design against vibrations and impact during ordinary straight motion

An industry wise glimpse at the array of applications where THK’s LM Guide is used.

Machine Tools (SHS,SSR,SNR,SNS,SRG,HSR,NR,VR) Horizontal machining centres Surface grinding machines Milling machines NC lathes XYZ axes of heavy cutting m/c tools CNC hobbing machines Travelling units of robots Precision Bridge Carrier	Medical (HMG,HCR,HSR,SHS,SRS) Resin welding equipment X-ray equipment Automatic haematological analysis equipment Medical X-ray CT scanners Bathing facilities with electric wheelchair support Surgery support robots
Industrial Robots (HR,GSR,HSR,SR,SHS,SSR) 5-joint closed-link robots Arc welding robots Scalar robots Double-arm robots	General Industrial Machinery (SSR,JR,SNR,SRN,SR,SNS,NRS) Electric injection moulding machines Punching presses Resin welding equipment Horizontal compression baling machines
Precision Instruments (SCR,CSR,HMG,SHS,HSR) Large 3-dimensional measuring devices Small measuring microscopes Grain inspectors	Semiconductor and LCD manufacturing (RSR,SRS,MX,RSH,HRW,SHW,HSR) Glass edge polishing units Glass substrate conveyor equipment LCD panel prober table units Dicing saws
ElectronicDevices (RSR,SRS,MX,RSH,HR) Various portable TV camera systems Automatic teller machines (ATMs) Compact photo development apparatus	Transportsystems (VR,VB,SR,SSR,HSR,SHS) Single-seater helicopters Platform doors Seat sliding mechanisms
Construction (SCR,CSR,MX,JR,NR,SNR,SNS) Building Vibration control structures Quake-absorbing structures for houses Shield machines	Other Manufacturing Industries (HR,GSR,HSR,SHS,SR,SSR) Dyeing machines Stone cutters, woodworking Foam processing machines for casting