LM Stroke, Bushing (Straight / With Seal) ST-UU Type, ST-UUB Type
Caution
- Some of the items are scheduled to be discontinued as of end of March in 2023. The manufacturer keep the items produced but they are not available with Misumi.
There are not the replacement items and the plan to resumption of sale. Please check the quotation and order screen for details.
Product Description
Hardened shaft, recommended for use with outer diameter tolerance (k5, m5, n5 or p5).
[Features]
· [Extremely low friction coefficient] Enables rotation with extremely low friction coefficient (=0.0006 to 0.0012) due to point contacts between the balls and ball rolling surface, and the separation of the balls within the ball cage.
· [Compact-design] Since the cross-sectional profile is simply the combination of the thin-walled outer cylinder and the balls, the outer diameter of this bearing is small and it is suitable for lightweight and space-saving compact designs.
· [High accuracy and low price] The sliding parts can be manufactured at low cost and a high level of accuracy is obtained.
Drawing
ST: UU type
(for light load)
ST: UUB type
(for medium load)
Specifications Table
| Part number | Maximum Stroke | Main dimensions | Basic dynamic load rating C kN | Basic static rated load C0 kN | Weight g | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Inscribed circle diameter | Outer diameter | Length | L1 | L2 | t | d0 | r | ||||||||
| dr | Tolerance | D | Tolerance | L | Tolerance | ||||||||||
| ST 8UU | 14 | 8 | +0.022 +0.013 | 15 | 0 -0.008 | 24 | 0 -0.2 | 15.3 | 1.5 | 0.5 | 1.5 | 0.5 | 0.98 | 0.27 | 17 |
| ST 10UU | 16 | 10 | 19 | 0 -0.009 | 30 | 18.5 | 1.5 | 0.5 | 1.5 | 0.5 | 2.35 | 0.62 | 31 | ||
| ST 12UU | 17 | 12 | +0.027 +0.016 | 23 | 32 | 20.1 | 1.5 | 0.5 | 1.5 | 0.5 | 4.02 | 1.08 | 49 | ||
| ST 16UU | 24 | 16 | 28 | 37 | 24.1 | 1.5 | 0.5 | 1.5 | 0.5 | 4.02 | 1.27 | 80 | |||
| ST 20UU ST 20UUB | 32 12 | 20 | +0.033 +0.020 | 32 | 0 -0.011 | 45 | 30.8 | 2 | 0.5 | 2 | 0.5 | 4.12 8.33 | 1.57 3.24 | 112 125 | |
| ST 25UU ST 25UUB | 32 12 | 25 | 37 | 45 | 0 -0.3 | 30.8 | 2 | 0.5 | 2 | 1 | 4.12 8.14 | 1.76 3.63 | 132 145 | ||
| ST 30UU ST 30UUB | 65 27 | 30 | 45 | 65 | 50.1 | 2.5 | 0.5 | 2.5 | 1 | 9.31 18.7 | 4.12 8.14 | 245 280 | |||
| ST 35UU ST 35UUB | 75 37 | 35 | +0.041 +0.025 | 52 | 0 -0.013 | 70 | 55.1 | 2.5 | 0.7 | 2.5 | 1.5 | 9.41 18.7 | 4.51 9.02 | 375 420 | |
| ST 40UU ST 40UUB | 91 49 | 40 | 60 | 80 | 64.9 | 2.5 | 0.7 | 2.5 | 1.5 | 12.5 25 | 6.18 12.4 | 580 640 | |||
| ST 45UU ST 45UUB | 91 49 | 45 | 65 | 80 | 64.9 | 2.5 | 0.7 | 2.5 | 1.5 | 12.6 25.2 | 6.76 13.5 | 635 705 | |||
| ST 50UU ST 50UUB | 120 70 | 50 | +0.041 +0.025 | 72 | 0 -0.013 | 100 | 0 -0.3 | 83.4 | 3 | 1 | 3 | 1.5 | 16.3 32.5 | 8.82 17.7 | 920 1,030 |
| ST 55UU ST 55UUB | 120 70 | 55 | +0.049 +0.030 | 80 | 100 | 83.4 | 3 | 1 | 3 | 2 | 16.6 33 | 9.71 19.3 | 1,280 1,400 | ||
| ST 60UU ST 60UUB | 120 70 | 60 | 85 | 0 -0.015 | 100 | 83.4 | 3 | 1 | 3 | 2 | 16.8 33.6 | 10.5 21 | 1,370 1,490 | ||
| ST 70UU ST 70UUB | 120 70 | 70 | 95 | 100 | 0 -0.4 | 83.4 | 3 | 1 | 3 | 2 | 16.9 33.8 | 11.7 23.3 | 1,540 1,680 | ||
| ST 80UU ST 80UUB | 114 58 | 80 | 110 | 100 | 83 | 3 | 1.5 | 3 | 2 | 21.3 42.5 | 15.3 30.6 | 2,240 2,450 | |||
| ST 90UU ST 90UUB | 114 58 | 90 | +0.058 +0.036 | 120 | 100 | 83 | 3 | 1.5 | 3 | 2 | 21.7 43.3 | 16.9 33.7 | 2,470 2,700 | ||
| ST 100UU ST 100UUB | 114 58 | 100 | 130 | 0 -0.018 | 100 | 83 | 3 | 1.5 | 3 | 2 | 22 43.9 | 18.3 36.8 | 2,700 2,940 | ||
Product Feature Details
Structure of LM Stroke ST Type
As shown in Figure 1, the ST type incorporates a ball cage and balls inside a precisely ground cylindrical outer housing. The balls are arranged in a staggered pattern to distribute the load evenly. The ball cage uses a lightweight and high-rigidity machined cage made of light alloy, allowing it to reliably follow high-speed motion. In addition, thrust rings and retaining rings are assembled on both sides of the inner diameter of the outer housing to prevent the ball cage from overrunning.
With this structure, rotary motion, reciprocating motion, and complex motion can be achieved with a low coefficient of friction. The stroke length can be obtained up to twice the range in which the ball cage can move within the outer housing.
Extremely Low Coefficient of Friction
Because the ball and the ball rolling surface are in point contact, which results in minimal rolling loss, and each ball is separated and held by the ball cage, rolling motion is possible with an extremely low coefficient of friction (μ = 0.0006 to 0.0012).
Compact design
Because the cross-sectional shape consists only of a thin outer housing and balls, the bearing's outer diameter can be kept small, resulting in a lightweight, space-saving compact design.
Types and Features
ST Type for Light Load
For light load applications where a large stroke length can be obtained.
Shaft diameter ⌀6 to ⌀100
Also available with seals. ST-UU type
ST-B type for medium load
This is a medium load type with the same dimension as the ST type, a shorter stroke length, and double the rated load.
Shaft diameter ⌀8 to ⌀100
Also available with seals. ST-UUB Type
Cautions and Prohibitions
Handling
(1) Do not disassemble each part. It may cause loss of function.
(2) Do not drop or hit the LM stroke. 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) If a contaminant enters the LM stroke ST type, it may cause abnormal wear or shorten the lifespan. If the ingress of contaminants is anticipated, it is important to select an effective sealing or dust-proof device that matches the operating environment conditions. For the LM stroke ST type, model numbers are available with a special synthetic rubber seal (ST: UU type) that offers excellent abrasion resistance as a dust-proof seal, or a felt seal (ST: DD type) that provides high dust-proof performance with low seal resistance.
(2) If cutting chips or other contaminants adhere to the product, clean it and then reapply lubricant.
(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 the product is used in environments where cutting chips, coolant, corrosive solvents, water, or similar substances may enter the interior, please prevent ingress into the product by using bellows, covers, or similar protective measures.
(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. In addition, it is recommended to periodically perform a stroke movement approximately equal to the length of the ball cage to form an oil film on the rolling surfaces and rolling elements.
(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 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.
Rubber seal
(Standard)
Felt seal
(Specified)
Lubrication
(1) Wipe off the anti-rust oil thoroughly and fill with 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 LM stroke.
(6) After greasing, the mixing resistance of the grease may increase the sliding resistance of the LM stroke. Be sure to perform a break-in operation to 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.
(10) For lubrication of the LM stroke ST type, both oil lubrication and grease lubrication can be used. Please select the most appropriate type for the given application based on the DN value. For grease lubrication, lithium-soap-based grease No. 2 is recommended.
Storage
Please store the LM stroke 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.