LM40UU 40x60x80 Linear Ball Bearing – Linear Bushing for 40 mm Shaft

LM40UU 40x60x80 Linear Ball Bearing – Linear Bushing for 40 mm Shaft

LM40UU, also written as LM 40 UU, is a cylindrical linear ball bearing / linear bushing designed for linear movement along a round shaft with a nominal diameter of 40 mm. Its standard dimensions are 40x60x80 mm: inside diameter d = 40 mm, outside diameter D = 60 mm and overall length L = 80 mm.

Exact product identification:

LM40UU – LM 40 UU – 40x60x80 mm – linear ball bearing – linear bushing – ball bushing – 40 mm shaft – JIS dimensional series

LM40UU – Technical Characteristics

LM40UU belongs to the family of recirculating-ball linear bearings used to guide components moving along a round linear shaft.

The rolling elements are balls circulating through internal raceway and return paths. During operation, balls in the loaded zone roll between the shaft and the bearing's load-carrying elements before recirculating through the return channels.

This allows the bearing to provide linear guidance using rolling contact.

The principal dimensions of standard LM40UU are:

d = 40 mm

D = 60 mm

L = 80 mm.

The bearing is therefore designed nominally for a:

Ø40 mm linear shaft.

LM40UU Dimensions

The most important dimensional search and identification format is:

LM40UU 40x60x80 mm.

These dimensions should be checked when selecting a replacement because another 40 mm linear bearing series may use a different outside diameter or overall length.

How Does an LM40UU Linear Bearing Work?

LM40UU supports linear movement along a cylindrical guide shaft.

Inside the bearing, balls circulate through recirculation paths. Balls in the loaded zone transfer forces between the shaft and the bearing assembly, while balls leaving the loaded section return through internal channels.

The balls then re-enter the loaded zone, allowing repeated linear travel.

LM40UU is therefore primarily a:

linear-motion bearing

rather than a conventional bearing designed primarily for rotary shaft motion.

What Does LM40UU Mean?

The designation provides key information about the bearing family and size.

LM – linear ball bearing / linear bushing series associated with the JIS dimensional standard.

40 – nominal diameter of the corresponding linear shaft: 40 mm.

UU – sealed version.

The same product type may be described in English technical searches as:

linear bearing

linear ball bearing

linear bushing

ball bushing

linear ball bushing

or:

recirculating ball linear bearing.

LM40UU and the JIS Dimensional Series

The LM series follows a dimensional system commonly associated with the Japanese/JIS linear-bearing standard.

For LM40UU, the key outside diameter is:

D = 60 mm.

This is important when comparing LM40UU with bearings from the LME dimensional series.

A particularly important distinction is:

LM40UU = 40x60x80 mm

while:

LME40UU = 40x62x80 mm.

Both are nominally designed for a 40 mm shaft, but the outside diameters are different.

Therefore:

LM40UU and LME40UU should not be treated as dimensionally identical bearings.

A housing designed for a 60 mm outside diameter is fundamentally different from one designed for a 62 mm outside diameter.

LM40UU for a 40 mm Linear Shaft

The nominal bore of LM40UU is:

40 mm.

It is therefore intended for use with a suitable:

40 mm precision linear shaft.

The shaft forms part of the complete linear-motion system. Shaft diameter tolerance, dimensional accuracy, surface condition and hardness requirements should be selected according to the bearing manufacturer's technical recommendations.

A generic steel bar with a nominal 40 mm diameter should not automatically be considered equivalent to a precision linear shaft.

LM40UU Construction

A typical LM40UU linear ball bearing consists of:

cylindrical outer sleeve

recirculating rolling elements – balls

ball-retaining and recirculation structure

internal return paths

and:

sealing elements.

The cylindrical, non-flanged design allows the bearing to be installed in a suitable housing.

The exact materials, number of ball circuits, internal construction details and load ratings may differ between manufacturers.

For this reason, manufacturer-specific technical parameters should not be transferred automatically from one LM40UU brand to another.

Sealed UU Version

The suffix:

UU

identifies the sealed version of the linear bearing.

Sealing elements help protect the internal ball-circulation system from external contamination and help retain lubricant within the working area.

However, a sealed linear bearing is not automatically suitable for every contaminated, wet or abrasive environment.

Environmental suitability depends on the exact bearing design, sealing system, shaft condition, lubrication and operating conditions.

Are All LM40UU Bearings Identical?

No.

LM40UU is a standardized-style designation used by multiple linear-bearing manufacturers.

Products can therefore be found under designations such as:

THK LM40UU

SAMICK LM40UU

FBJ LM40UU

and various neutral or alternative-brand LM40UU bearings.

Their principal installation dimensions may be the same:

40x60x80 mm,

but manufacturer-specific parameters can differ.

These may include:

dynamic load rating

static load rating

number of ball circuits

bearing mass

retainer material

seal design

manufacturing accuracy

and:

recommended shaft and housing tolerances.

For this reason, a generic LM40UU description should not assign load ratings taken from one specific manufacturer.

LM40UU vs LME40UU

This is one of the most important distinctions when selecting a 40 mm linear bearing.

LM40UU: 40x60x80 mm

LME40UU: 40x62x80 mm

The bore and length can be the same, but the outside diameter differs by:

2 mm.

Therefore, an LME40UU with a 62 mm outside diameter should not be installed as a direct dimensional replacement in a housing designed for an LM40UU with a 60 mm outside diameter without verifying and modifying the housing arrangement.

Always check the complete dimensional designation rather than searching only for:

40 mm linear bearing.

LM40UU vs Rotary Ball Bearing

LM40UU is not a conventional deep-groove or radial ball bearing intended primarily for rotary motion.

Its principal function is:

linear guidance along a round shaft.

The 40 mm dimension therefore identifies the nominal diameter of the linear guide shaft.

This distinguishes LM40UU from conventional rotary bearings that may also have a 40 mm bore but are designed for fundamentally different motion and mounting conditions.

Selection and Interchangeability

When selecting an LM40UU or equivalent linear bearing, compare:

nominal shaft diameter – 40 mm

inside diameter d – 40 mm

outside diameter D – 60 mm

overall length L – 80 mm

linear-bearing series

sealed construction

housing requirements

load capacity

accuracy requirements

shaft specifications

and:

manufacturer-specific technical data.

Matching only the 40 mm bore is insufficient.

A replacement should match the complete installation geometry and satisfy the required operating conditions.

Applications of LM40UU

LM40UU linear ball bearings are used in mechanisms requiring controlled linear movement along round guide shafts.

Typical application areas include:

industrial automation

production machinery

linear positioning systems

sliding tables

assembly equipment

CNC-related mechanisms

robotics

handling systems

special-purpose machinery

and:

linear guide assemblies.

Suitability for a particular machine depends on load, speed, travel length, required accuracy, environmental conditions, lubrication, shaft specification and housing design.

How Is LM40UU Searched Online?

Users enter the LM40UU designation in many different formats. Important search variations include:

• LM40UU
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The exact dimensional identity of standard LM40UU is:

40x60x80 mm.

When searching for an equivalent, particular attention should be paid to the difference between LM40UU and LME40UU.

Technical Specification

FAQ

What are the dimensions of LM40UU?

Standard LM40UU measures 40x60x80 mm, with d = 40 mm, D = 60 mm and L = 80 mm.

What shaft diameter is LM40UU designed for?

LM40UU is nominally designed for a 40 mm linear shaft.

Is LM40UU a linear bearing?

Yes. LM40UU is a linear ball bearing, also called a linear bushing, ball bushing or linear ball bushing.

What does UU mean in LM40UU?

UU identifies the sealed version of the linear bearing.

Is LM40UU the same as LME40UU?

No. Standard LM40UU measures 40x60x80 mm, while LME40UU measures 40x62x80 mm. The 2 mm difference in outside diameter is critical when fitting the bearing into a housing.

Are LM40UU bearings from different manufacturers interchangeable?

They may share the same principal installation dimensions, but complete interchangeability should be checked against manufacturer documentation. Load ratings, accuracy, seals, retainer construction and other technical parameters may differ.

Is LM40UU designed for rotary motion?

Its primary function is linear movement along a round guide shaft, not conventional rotary shaft support.

What are alternative names for LM40UU?

Common names include 40 mm linear bearing, 40 mm linear ball bearing, linear bushing 40 mm, ball bushing 40 mm, LM40UU linear bushing and 40x60x80 linear bearing.

AI Overview

LM40UU (LM 40 UU) is a sealed linear ball bearing / linear bushing measuring 40x60x80 mm, designed for a nominal 40 mm linear shaft. It has d = 40 mm, D = 60 mm and L = 80 mm. The LM series follows the JIS dimensional standard, while UU identifies the sealed version.