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Selection and design of OILES bearings

Describes the basic design items useful for designing better OILES bearings.

Selection and Design

Design and required performance features

1. Determination of rough layout

Determine I.D., O.D., length of the bearing, material of the mating shaft and lubrication method.

2. Confirmation of application environment and design specifications

  • Normal environment: room temp, atmospheric air
  • Special environment: high/low temp., underwater, chemical liquid

3. Study of application condition

  • Study allowable P,V, PV value, operating motion, frequency, availability of oiling, environmental conditions, temperature, foreign particles, corrosion resistance and chemical resistance.
  • Study dynamic load, static load, impact load, static stress and impact strength.
  • Attention should be paid to special environment.

4. Study of configuration design, detail design and standard products

  • Confirm and verify material, strength, rigidity, accuracy of housing and the mating shaft.
  • Confirm and verify bearing accuracy, clearance, oil grooves and oil holes.
  • Study restrictions on bearing material manufacturing.
    Study possibility of standard products.

5. Selection of primary material

Study whether each design factor falls within each allowable limit. Then decide the material.

6. Confirmation of existing data and characteristics of the bearing

Confirm initial characteristics based on the test data and verify estimated service life and durability of the bearing.

Determination of recommended Oiles bearings

P / V / PV value

P

Contact pressure P which is obtained by dividing maximum load (w) by projected loading area. (φdxL)

V

Relative velocity between the bearing and the mating shaft.

PV value

Product of the contact pressure P and the velocity V. This is the most important value in selecting bearing.

These values are not independent allowable values but are interrelated design values.
When designing, values should fall under the range as shown in this graph.

Allowable max. PV value < allowable max. contact pressure : P max. × allowable max. velocity : V max.

Environmental temperature and PV value

Service temperature range listed on the Product page indicates heat resistance derived from the material and the structure of the bearings. Depending on the environmental temperature, it is necessary to design the bearing based on the below conditions.

When a bearing is used in high temperature:

When a bearing is used in low temperature:

Compared to the metallic bearing, plastic bearing (especially thermoplastic resin material) has the lower melting point and therefore, is prone to heat effect. As heat expansion coefficient is big, attention should be paid in fitting design such as stress relaxation, decrease in clearance due to temperature change and others.

Selection of mating materials

Bearing performance is influenced by the material, hardness, surface roughness and surface treatment of the mating shaft. In order to select appropriate mating material, please refer to the chart below. If used in a corrosive environment such as in the seawater, or in the chemical liquid, double or triple chrome plating should be done.

Bearing Contact pressure
N/mm2{kgf/cm2}
Material Hardness Surface roughness Ra(Ry)
Metallic Bearings ~24.5{250} Carbon steel for machine structure alloy steel
(S45C、SNC415、SCM435)
In corrosive environment, corrosion resistant steel.
(SUS304、SUS403、SUS420)
HB150 or over Less than
1.6a(6,3s)
24.5{250} ~49.0{500} Surface hardening treatment such as induction hardening and carburizing should be implemented for the materials described above. HB250 or over
49.0{500} ~98.0{1000} In addition to surface hardening treatment as above, additional surface treatment such as nitriding treatment and hard chrome plating should be implemented. HRC50 or over
Plastic and Multi-layer Bearings ~49.0{500} Carbon steel for machine structure alloy steel
(S45C、SNC415、SCM435)
In corrosive environment, corrosion resistant steel.
(SUS304、SUS403、SUS420)
HB120 or over Less than
0.8a(3.2s)
49.0{500} ~
98.0{1000}
Surface treatment such as induction hardening, quenching by carburizing and hard chrome plating should be implemented for the materials described above. HRC45 or over

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