Linear Bushing LMK Type (Flange Type, Square Shape)

Brand :

THK

Caution

Product Description

A linear bushing with a low center height that enables a compact design.
[Features]
· Achieves linear motion with minimal frictional resistance, providing high accuracy and smooth movement.
· This type has four flat locations on the flange of the round flange LMF type.
· Compared to the round flange type, it has a lower center height, enabling a more compact design.

Drawing

Specifications Table

Part number Standard type	Ball List	Main dimensions
		Inscribed circle diameter		Outer diameter		Length		Flange diameter		K	H	PCD	Mounting hole d₁ x d₂ x h
		dr	Tolerance	D	Tolerance	L	Tolerance	D₁	Tolerance	K	H	PCD	Mounting hole d₁ x d₂ x h
LMK 6	4	6	0 -0.009	12	0 -0.011	19	0 -0.2	28	0 -0.2	22	5	20	3.4 x 6.5 x 3.3
LMK 8S	4	8		15		17		32		25	5	24	3.4 x 6.5 x 3.3
LMK 8	4	8		15		24		32		25	5	24	3.4 x 6.5 x 3.3
LMK 10	4	10		19	0 -0.013	29		39		30	6	29	4.5 x 8 x 4.4
LMK 12	4	12		21		30		42		32	6	32	4.5 x 8 x 4.4
LMK 13	4	13		23		32		43		34	6	33	4.5 x 8 x 4.4
LMK 16	5	16		28		37		48		37	6	38	4.5 x 8 x 4.4
LMK 20	5	20	0 -0.010	32	0 -0.016	42		54		42	8	43	5.5 x 9.2 x 5.4
LMK 25	6	25		40		59	0 -0.3	62		50	8	51	5.5 x 9.2 x 5.4
LMK 30	6	30		45		64		74		58	10	60	6.6 x 11 x 6.5
LMK 35	6	35	0 -0.012	52	0 -0.019	70		82		64	10	67	6.6 x 11 x 6.5
LMK 40	6	40		60		80		96	0 -0.3	75	13	78	9 x 14 x 8.6
LMK 50	6	50		80		100		116		92	13	98	9 x 14 x 8.6
LMK 60	6	60	0 -0.015	90	0 -0.022	110		134		106	18	112	11 x 17.5 x 10.8

Part number Standard type	Flange Perpendicularity μm	Eccentricity (Maximum) μm	Radial Clearance Tolerance μm	Standard rated load		Weight g
				C N	C₀ N
				C N	C₀ N
LMK 6	12	12	-5	206	265	17
LMK 8S	12	12	-5	176	225	25
LMK 8	12	12	-5	265	402	26
LMK 10	12	12	-5	373	549	45
LMK 12	12	12	-5	412	598	50
LMK 13	12	12	-7	510	775	67
LMK 16	12	12	-7	775	1,180	105
LMK 20	15	15	-9	863	1,370	130
LMK 25	15	15	-9	980	1,570	270
LMK 30	15	15	-9	1,570	2,750	344
LMK 35	20	20	-13	1,670	3,140	487
LMK 40	20	20	-13	2,160	4,020	790
LMK 50	20	20	-13	3,820	7,940	1,705
LMK 60	25	25	-13	4,710	10,000	2,278

Note: Since a resin retainer is incorporated, avoid use at temperatures exceeding 80°C.

Linear bushing LMK type (flange type, square shape) model number examples

Note: If an oil hole is required, you can specify it by adding the symbol OH at the end of the part number.

Product Feature Details

Structure of Linear Bushing LM: UU Type

Linear bushings are used in combination with cylindrical LM shafts and are products that perform linear motion.
Since the load balls and LM shaft are in point contact, linear motion is achieved with minimal frictional resistance, resulting in smooth movement.
The outer housing is made of high carbon chrome bearing steel, and after heat treatment, the inner diameter and outer diameter are ground and finished.
Linear bushings are used in office equipment, medical devices, packaging machines, and other applications where there is a light load and no vibration or impact.
However, they cannot be used in applications where a load is applied in the rotating direction.

Compatibility
The linear bushing and LM shaft are compatible, allowing you to freely combine and use them as needed.

Low Noise
The standard type is equipped with a resin-molded retainer to keep the balls captive, enabling low-noise and smooth operation.

Wide Variety
A wide range of types is available, including standard type, clearance adjustment type, open type, long type, pilot flange type, and flange type LM case units, allowing you to select the most suitable model for your application.

Cautions and Prohibitions

Handling

(1) Disassembling each part may allow foreign matter to enter or reduce the assembly accuracy of each part, so do not disassemble.
(2) Do not drop or hit the linear bushing. It may cause injury or damage. In addition, please note that when shock was applied, the product may lose its function even though there is no visible damage to the external appearance.
(3) When handling the product, wear protective gloves, safety shoes, and the like as necessary to ensure safety.

Precautions for use

(1) Be careful to prevent cutting chip, coolant, or other contaminant from entering. Otherwise, it may cause damage.
(2) If the product is used in environments where cutting chip, coolant, corrosive solvents, water, etc. may enter the interior, avoid entry into the product by using bellows, cover, or similar protection.
(3) Avoid using the product at temperatures exceeding 80°C. If the temperature exceeds this level, resin and rubber parts may be deformed or damaged.
(4) If cutting chip or other contaminant adheres to the product, please clean it and then reapply lubricant.
(5) In cases of small stroke, it is difficult for an oil film to form on the contact surfaces between the rolling surface and the rolling element, which may cause fretting. Therefore, please use grease with excellent fretting resistance. Additionally, it is recommended to periodically move the stroke by approximately the length of the outer cylinder to help form an oil film on the rolling surface and rolling element.
(6) Do not forcibly drive positioning components (such as pins or keys) into the product. This may cause indentations on the rolling surfaces and result in loss of function.
(7) If the shaft is inserted at an angle, there is a possibility of contaminant ingress, damage to internal components, and the rolling element falling out.
(8) Using the product with the rolling element removed may cause early breakage.
(9) If the rolling element falls out, do not use the product as is; please contact THK.
(10) If the rigidity and accuracy of the mounting components are insufficient, the load on the bearing will be locally concentrated, and the bearing performance will be significantly reduced. Therefore, please thoroughly consider the rigidity and accuracy of the housing and base, as well as the strength of the fixing bolts.

Lubrication

(1) Wipe off the anti-rust oil thoroughly and apply lubricant before use.
(2) Avoid mixing different lubricants. Even if the thickener is the same type of grease, differences in additives and other components may have adverse effects on each other.
(3) When used in special environments such as locations subject to constant vibration, clean rooms, vacuum, or extreme low or high temperatures, please use grease suitable for the specifications and environment.
(4) When lubricating the product, apply lubricant directly to the rolling surface and perform several break-in strokes to ensure grease enters the interior.
(5) The consistency of the grease changes depending on the temperature. Please note that changes in consistency will also affect the sliding resistance of the linear bushing.
(6) After greasing, the mixing resistance of the grease may increase the sliding resistance of the linear bushing. Be sure to perform a break-in operation and allow the grease to fully spread before operating the machine.
(7) Immediately after greasing, excess grease may scatter around the area, so please wipe it off as needed before use.
(8) The properties of grease deteriorate and its lubrication performance declines over time, so it is necessary to inspect and replenish the grease according to usage frequency.
(9) Lubrication intervals vary depending on usage conditions and operating environment. Please determine the final lubrication interval and amount based on actual machine operation.

Storage

Please store the linear bushing indoors, in THK's packaging and shipping configuration, avoiding high temperatures, low temperatures, and high humidity.

Disposal

Please dispose of the product appropriately as industrial waste.