Linear Bushing
| Product name | Linear Bushings with Pillow Blocks - Single Bushing, Wide Block |
| Part number | LHBBF30 |
| Features | Spec-designed to save the time of manufacturing a housing and installing a linear bushing, and to be tightly secured to a workpiece through four mounting holes. |
* Orange colored cells in the table below indicate the part numbers used in this example.
Selection criteria
Housing Unit type meets design requirements.
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Available sizes
■Linear Bushings with Pillow Blocks - Single Bushing, Wide Block
| Linear Bushing Used | Holder |
| Material | Surface Treatment |
| Single | Aluminum Alloy | Clear Anodize |
■Sizes and Dimensions.
I.D. (mm) | Overall Length (mm) | Mounting screw Dia. |
| 5 | 18 | M3 |
| 6 | 25 | M4 |
| 8 | 30 |
| 10 | 35 | M5 |
| 12 | 36 |
| 13 | 39 |
| 16 | 44 |
| 20 | 50 |
| 25 | 67 | M6 |
| 30 | 72 | M8 |
| 35 | 80 |
| 40 | 90 | M10 |
| 50 | 110 |
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Selection Steps
■Linear Bushings with Pillow Blocks Selection Steps.
- Determine Application Conditions
- (loads, motion pattern, life)
↓
- Temporarily select linear bushing specifications
- (select the shaft diameter, length, and etc. based on the conditions of use.)
↓
- Basic safety check
-
- ● Basic static load rating.
- ● Basic dynamic load rating.
- ● Allowable static moment.
- ● Life.
↓
- Considerations based on the required performance
- ● Life variations due to various changes (temperature, hardness, etc.)
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Accuracy Info
■Accuracy of Linear Bushings with Pillow Blocks
(mm)
| I.D. | I.D. Tolerance | Tolerance of Height from Table Top |
| 5 | 0 -0.009 | ±0.02 |
| 6 |
| 8 |
| 10 |
| 12 |
| 13 |
| 16 |
| 20 | 0 -0.010 |
| 25 |
| 30 |
| 35 | 0 -0.012 |
| 40 |
| 50 |
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Performance info.
■Speeds
Load Information for Linear Bushings with Pillow Blocks.
| I.D. | Basic Load Rating |
| (mm) | Basic Dynamic Load Rating(N) | Basic Staic Load Rating(N) |
| 5 | 167 | 206 |
| 6 | 206 | 265 |
| 8 | 265 | 380 |
| 10 | 372 | 549 |
| 12 | 412 | 598 |
| 13 | 510 | 784 |
| 16 | 775 | 1180 |
| 20 | 882 | 1370 |
| 25 | 980 | 1570 |
| 30 | 1570 | 2740 |
| 35 | 1670 | 3140 |
| 40 | 2160 | 4020 |
| 50 | 3820 | 7940 |
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Technical calculations
■Life of Flanged Linear Bushings.
When the linear system is in motion with applied load, the rolling surfaces and races are subject to repeated stress, This stress can cause scale-like flaking due to material fatigue. The total run distance until the flaking appears in the "Life" of the linear system.
Rated life can be calculated with the basic dynamic load rating and the actual load applied to the linear bushings, as shown below.
- L: Rated Life (km).
- fH: Hardness Factor (See Fig.1).
- fT: Temperature Factor (See Fig. 2).
- fC: Contact Factor (See Table-3).
- fW: Load Factor (See Table-4).
- C: Basic Dynamic Load Rating (N).
- P: Applied Load (N).
● Hardness Factor (fH).
For linear applications, the shafts and ball bearings must have sufficient hardness. If they do not, the load rating decreases and the life will be reduced.
Raceway Surface Hardness.
●Temperature Factor (fT).
When the temperature of the linear system exceeds 100 degrees C, the hardness will decrease and as a result, the allowable load and life will reduced.
Linear System Temperature.
● Contact Factor (fC).
In general, it is common to use two or more bushings on one shaft. In these cases, the load on each bushing will vary depending on the machining precision and will not have equally distributed loads. As a result, the allowable load per bushing will vary depending on the number of bushings used on the rail.
Table-3. Contact factor
| Number of Bearings Installed on One Shaft | Contact Factor Fc |
| 1 | 1 |
| 2 | 0.81 |
| 3 | 0.72 |
| 4 | 0.66 |
| 5 | 0.61 |
Load Factor (fW)
To calculate the load applied to the linear bushings, in addition to the object weight, the inertia force attributed to the motion velocity, moment loads and the variations of each over time must be obtained. However, for reciprocating motion applications, it is difficultto obtain accurate calculations due to the effects of the vibrations and shocks. Therefore, use Table 2 to simplify the life calculations.
| Conditions of Use | fw |
No external shocks / vibrations, low speed 15 m/min or less | 1.0~1.5 |
No significant shocks / vibrations, medium speed 60 m/min or less | 1.5~2.0 |
With external shocks / vibrations, high speed exceeding 60 m/min | 2.0~3.5 |
Life can be obtained by calculating the travel distance per unit of time. When the stroke length and the number of strokes are constant, it can be calculated using the formula below.
- Lh: Life (hr.).
- L: Rated Life (km).
- Ls: Stroke Length (m).
- n1: Cycles per Minute (cpm).
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