Linear tables with closed shaft guidance system
Features
Linear tables LTE are linear units for positioning, handling and machining tasks. They are suitable for moderate loads and short stroke lengths.
Basic design
The basic design of linear tables LTE has no drive and comprises:
- a carriage unit made from aluminium alloy with four linear ball bearings KB and one lubrication nipple on each side of the carriage unit
- two hardened and ground shafts made from high alloy steel
- two shaft support blocks
- design A: movable carriage unit
- design B: stationary carriage unit.
Linear tables LTE are supplied already assembled.
The linear ball bearings have an initial greasing, are sealed and can be relubricated.
With trapezoidal screw drive
Linear tables LTE with trapezoidal screw drive comprise the basic design plus the following additional components:
- a rolled trapezoidal screw spindle with a cylindrical bronze nut
- on the drive side: a locating bearing in a shaft support block; depending on the table size, the locating bearing comprises one double row angular contact ball bearing or two single row angular contact ball bearings
- on the opposite side: a non-locating bearing in a shaft support block; the non-locating bearing comprises one single row ball bearing.
The spindle support bearings are sealed and lubricated for life. The spindle nut has an initial greasing, is sealed and can be relubricated via a lubrication nipple in the carriage unit.
With ball screw drive
Linear tables LTE with ball screw drive comprise the basic design plus the following additional components:
- a rolled ball screw spindle with a cylindrical single nut M. In the case of some pitch values, preloaded double nuts MM are also possible.
- on the drive side: a locating bearing in a shaft support block; the locating bearing comprises a preloaded double row angular contact ball bearing ZKLN and a lubrication nipple.
- on the opposite side: a non-locating bearing in a shaft support block; the non-locating bearing comprises a needle roller bearing NA and a lubrication nipple.
The spindle support bearings and spindle nuts have an initial greasing, are sealed and can be relubricated. The spindle nuts can be relubricated via a lubrication nipple in the carriage unit.
With bellows
Linear tables LTE can be equipped with two sets of bellows, with the following exceptions: LTE8 and LTE12. The bellows are attached by means of Velcro tape, with the exception of LTE20: In this case, the bellows are mounted using screws.
For the same stroke length, the total length of a linear table with bellows is greater than the total length of a linear table without bellows.
Screw drive
The spindle thread has a pitch value of between 3 mm and 50 mm, see table.
As standard, single nuts with an axial clearance dependent on the pitch are used. In the case of some pitch values, the ball screw drive can be supplied with preloaded double nuts.
Screw drive variants
Screw drive variants | Trapezoidal screw drive | Ball | Suffix | ||
|---|---|---|---|---|---|
Pitch | 3 | mm | ● | ‒ | 3 |
4 | mm | ● | ● | 4 | |
5 | mm | ● | ● | 5 | |
6 | mm | ● | ‒ | 6 | |
8 | mm | ● | ‒ | 8 | |
10 | mm | ● | ● | 10 | |
20 | mm | ‒ | ● | 20 | |
40 | mm | ‒ | ● | 40 | |
50 | mm | ‒ | ● | 50 | |
Single nut (cylindrical) | ● | ● | M | ||
Double nut (cylindrical) | ‒ | ● | MM | ||
Without drive (no spindle), | ‒ | ‒ | OA | ||
Drive elements
For linear tables, Schaeffler also supplies couplings, coupling housings, planetary gearboxes and servo motors, ➤ Figure. The range is supplemented by servo controllers for effective drive and control of the motors.
Linear table
with closed shaft guidance system
Proven drive combinations
For vertical and horizontal applications, the necessary drive components can be combined as a function of the mass to be moved, the acceleration and the travel velocity of the carriages.
ATTENTION
For vertical mounting, motors with a holding brake must be used.
If different loading and kinematic criteria apply, calculation should be based on the least favourable operating conditions. This applies to calculation of the drive motor and design of the gearbox, coupling and servo controller.
Special designs
Special designs are available by agreement. Examples of these are linear tables LTE with
- guidance shafts and spindles with anti-corrosion protection and a Permaglide guidance system
- bellows resistant to welding beads
- a rolled ball screw spindle to accuracy class 25 μm/300 mm
- a trapezoidal screw drive with a left hand thread
- inductive limit switches
- special machining.
Design and safety guidelines
Load carrying capacity and
load safety factor
The load carrying capacities and load safety factors to be observed differ as a function of the mounting position.
Preload and rigidity
A preloaded linear guidance system increases the rigidity of a machine system. However, preload also influences the displacement resistance and operating life of the linear guidance system.
Linear tables LTE with linear ball bearings cannot, due to their construction, be regarded as preloaded. Individually, each linear ball bearing has operating clearance on the guidance shaft. The operating clearance of the individual linear ball bearings is substantially eliminated and is no longer relevant in practical terms. This is due to the compact, rigid carriage unit and the positional tolerances of the locating bore for the linear ball bearings relative to each other.
Main load direction of linear tables with linear ball bearings
The effective load rating of a linear ball bearing is dependent on the position of the load direction in relation to the position of the ball rows.
In the case of linear tables LTE, the linear ball bearings are not fitted in a specific alignment, so the basic load rating data C and C0 give the minimum values. The corresponds to a ball row in the linear ball bearing in an apex position relative to the load direction.
Load carrying capacity, dependent on the position of the ball rows
Deflection
The deflection of linear tables is essentially dependent on the support spacing, the rigidity of the shaft, the adjacent construction and the bearing arrangement. As the rigidity of these components increases, the deflection of the actuators is reduced.
The deflection restricts the effective length of a linear table with a movable carriage unit, design A, or the load carrying capacity.
Diagrams
The diagram values are determined for a bearing arrangement or clamping which is in theory infinitely rigid and are subdivided into locating/non-locating and locating/locating bearing arrangements, starting ➤ Figure. The influence of spindles in driven linear tables LTE has not been taken into consideration here.
The deflection of the support rail is valid under the following conditions:
- central position of the carriage unit
- vertical load
- horizontal mounting position of the linear table.
Due to shaft deflection, the rolling element rows adopt an apex position relative to the outside diameter of the machined linear ball bearing, but this should not be regarded as critical in the load ranges displayed in each case.
The running quality and operating life of the linear ball bearings are not substantially influenced by the guidance system concept “two shafts each with two linear ball bearings” of the linear tables LTE.
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Deflection about the z axis
Length calculation
of linear tables
The length calculation of linear tables is based on the required effective stroke length NH. The effective stroke length NH must be increased by the addition of safety spacing values on both sides of the travel distance. It is only if bellows are present that the effective length BL must be added.
The total length Ltot of the linear table is determined from the effective stroke length NH, the safety spacings S, the carriage unit length L and the lengths of the end plates L3, L4 and L5.
Parameters for length calculation
| GH | mm | Total stroke length |
| NH | mm | Effective stroke length |
| S | mm | Safety spacing, see table |
| L | mm | Length of carriage plate |
| L3 | mm | Length of end plates in LTE..-A-OA, LTE..-B-OA |
| L4 | mm | Length of end plate in LTE..-TR, LTE..-TGT, LTE..-KGT |
| L5 | mm | Length of end plate in LTE..-TR, LTE..-TGT, LTE..-KGT |
| Ltot | mm | Total length of linear table |
| FBL | Effective length factor according to linear table type | |
| BL | mm | Effective length of bellows |
| BB | mm | Length of bellows fastener. |
Total stroke length GH
The total stroke length GH is determined from the required effective stroke length NH and the safety spacings S, which must correspond to at least the spindle pitch P.
Maximum lengths of linear tables
The maximum length of linear tables LTE is determined taking account of the deflection, see table.
Maximum lengths
Designation | Ltot | Designation | Ltot | Designation | Ltot |
|---|---|---|---|---|---|
mm | mm | mm | |||
LTE08 | 1 000 | ‒ | ‒ |
| ‒ |
LTE12 | 1 200 | ‒ | ‒ |
| ‒ |
LTE16 | 1 400 | LTE16..-TR | 1 400 | LTE16..-KGT | 1 400 |
LTE20 | 1 800 | LTE20..-TGT | 1 800 | LTE20..-KGT | 1 800 |
LTE25 | 2 000 | LTE25..-TR | 2 000 | LTE25..-KGT | 2 000 |
LTE30 | 2 200 | LTE30..-TR | 2 200 | LTE30..-KGT | 2 200 |
LTE40 | 2 500 | LTE40..-TR | 2 500 | LTE40..-KGT | 2 500 |
LTE50 | 2 500 | LTE50..-TR | 2 500 | LTE50..-KGT | 2 500 |
Total length Ltot
The following ➤ equtions are designed for one linear table. The parameters and their position can be found in ➤ Figure and ➤ Figure as well as in the table.
Length parameters for linear tables LTE..-A and LTE..-B
Linear table without bellows, without drive
LTE..-A, LTE..-B
Linear table with bellows, without drive LTE..-A, LTE..-B
Length parameters for linear tables LTE..-TR, LTE..-TGT and LTE..-KGT
Linear table without bellows
LTE..-TR, LTE..-TGT, LTE..-KGT
Linear table with bellows
LTE..-TR, LTE..-TGT, LTE..-KGT
Length parameters
Valid for design A and design B
Designation | L | L3 | L4 | L5 | S | FBL | BB |
|---|---|---|---|---|---|---|---|
mm | mm | mm | mm | mm | |||
LTE08-65 | 65 | 12 | ‒ | ‒ | Dependent on application | ‒ | ‒ |
LTE12-85 | 85 | 14 | |||||
LTE16-100 | 100 | 18 | 1,5 | 20 | |||
LTE20-130..-OA | 130 | 20 | 1,33 | 20 | |||
LTE25-160 | 160 | 25 | 1,34 | 21 | |||
LTE30-180 | 180 | 25 | 1,27 | 21 | |||
LTE40-230 | 230 | 30 | 1,28 | 22 | |||
LTE50-280 | 280 | 30 | 1,24 | 22 | |||
LTE16-100..-TR12×3 | 100 | ‒ | 24 | 18 | 3 | 1,5 | 20 |
LTE20-130..-TGT16×4 | 130 | 29 | 20 | 4 | 1,33 | 20 | |
LTE25-160..-TR16×4 | 160 | 33 | 25 | 4 | 1,34 | 21 | |
LTE30-180..-TR20×4 | 180 | 38 | 25 | 4 | 1,27 | 21 | |
LTE30-180..-TR20×8 | 180 | 38 | 25 | 8 | 1,27 | 21 | |
LTE40-230..-TR24×5 | 230 | 39 | 30 | 5 | 1,28 | 22 | |
LTE40-230..-TR24×10 | 230 | 39 | 30 | 10 | 1,28 | 22 | |
LTE50-280..-TR32×6 | 280 | 42 | 30 | 6 | 1,24 | 22 | |
LTE16-100..-1204 | 100 | 24 | 18 | 4 | 1,5 | 20 | |
LTE16-100..-1205 | 100 | 24 | 18 | 5 | 1,5 | 20 | |
LTE20-130..-KGT/5 | 130 | 29 | 20 | 5 | 1,33 | 20 | |
LTE20-130..-KGT/10 | 130 | 29 | 20 | 10 | 1,33 | 20 | |
LTE25-160..-1605 | 160 | 33 | 25 | 5 | 1,34 | 21 | |
LTE25-160..-1610 | 160 | 33 | 25 | 10 | 1,34 | 21 | |
LTE30-180..-2005 | 180 | 38 | 25 | 5 | 1,27 | 21 | |
LTE30-180..-2010 | 180 | 38 | 25 | 10 | 1,27 | 21 | |
LTE30-180..-2020 | 180 | 38 | 25 | 20 | 1,27 | 21 | |
LTE30-180..-2050 | 180 | 38 | 25 | 50 | 1,27 | 21 | |
LTE40-230..-2505 | 230 | 39 | 30 | 5 | 1,28 | 22 | |
LTE40-230..-3210 | 230 | 42 | 30 | 10 | 1,28 | 22 | |
LTE40-230..-3220 | 230 | 42 | 30 | 20 | 1,28 | 22 | |
LTE40-230..-3240 | 230 | 42 | 30 | 40 | 1,28 | 22 | |
LTE50-280..-2505 | 280 | 39 | 30 | 5 | 1,24 | 22 | |
LTE50-280..-3210 | 280 | 42 | 30 | 10 | 1,24 | 22 | |
LTE50-280..-3220 | 280 | 42 | 30 | 20 | 1,24 | 22 | |
LTE50-280..-3240 | 280 | 42 | 30 | 40 | 1,24 | 22 |
Effective length of bellows
The effective length of bellows is the length occupied by the bellows in the fully compressed state. Calculation is based on the total stroke length GH, ➤ Figure, ➤ equation and table.
Effective length calculation
| BL | mm | Effective length of bellows |
| GH | mm | Total stroke length |
| FBL | – | Effective length factor according to linear table type, see table |
| BB | mm | Length of bellows fastener. |
Mass calculation
The total mass of a linear table is calculated from the mass of the table without a carriage unit and the carriage unit.
Values for mass calculation, linear table without screw drive
Designation | Mass | |
|---|---|---|
Carriage unit | Actuator | |
mLAW | mBOL | |
≈kg | ≈kg | |
LTE08..-A, LTE08..-B | 0,24 | Ltot · 0,000 8 + 0,35 |
LTE12..-A, LTE12..-B | 0,63 | Ltot · 0,001 8 + 0,86 |
LTE16..-A, LTE16..-B | 0,9 | Ltot · 0,003 1 + 1,3 |
LTE20..-A-OA, LTE20..-B-OA | 1,8 | Ltot · 0,004 9 + 2,5 |
LTE25..-A, LTE25..-B | 3,5 | Ltot · 0,007 7 + 4,9 |
LTE30..-A, LTE30..-B | 5,1 | Ltot · 0,011 0 + 6,8 |
LTE40..-A, LTE40..-B | 10,3 | Ltot · 0,019 6 + 13,4 |
LTE50..-A, LTE50..-B | 16,4 | Ltot · 0,030 6 + 20,6 |
Values for mass calculation, linear table with screw drive
Designation | Mass | |
|---|---|---|
Carriage unit** | Actuator | |
mLAW | mBOL | |
≈kg | ≈kg | |
LTE16..-A, LTE16..-B | 0,86 | Ltot · 0,003 9 + 0,4 |
LTE20..-A, LTE20..-B | 1,82 | Ltot · 0,006 2 + 0,8 |
LTE25..-A, LTE25..-B | 3,49 | Ltot · 0,009 0 + 1,4 |
LTE30..-A, LTE30..-B | 5,04 | Ltot · 0,013 1 + 1,9 |
LTE40..-A-25, LTE40..-B-25 | 4,3 | Ltot · 0,022 9 + 2,8 |
LTE40..-A-32, LTE40..-B-32 | 10,6 | Ltot · 0,025 3 + 3,4 |
LTE50..-A-25, LTE50..-B-25 | 4,3 | Ltot · 0,033 9 + 2,8 |
LTE50..-A-32, LTE50..-B-32 | 16,5 | Ltot · 0,036 3 + 4,7 |
**Including single or preloaded double nut.
Lubrication
The guidance systems and the trapezoidal or ball screw drive in linear tables are initially greased with a high quality lithium complex soap grease KP2P-30 according to DIN 51825 and must be relubricated during operation.
Structure of suitable greases
The following greases are suitable for the linear ball bearings and the linear recirculating ball bearing and guideway assemblies as well as the screw drives:
- lithium soap or lithium complex soap grease with base oil having a mineral oil base
- special anti-wear additives for loads C/P ＜ 8, indicated by “P” in the DIN designation
- base oil viscosity ISO VG 68 to ISO VG 100 in the case of linear recirculating ball bearing and guideway assemblies
- consistency in accordance with NLGI grade 2 in the case of linear ball bearings.
If different greases are used, their miscibility and compatibility must be checked first.
Relubrication intervals
The relubrication intervals are essentially dependent on the following factors:
- the travel velocity of the carriage unit
- the load
- the operating temperature
- the stroke length
- the environmental conditions and environmental influences
- the mounting position.
The cleaner the environment, the lower the lubricant consumption.
Calculation of the relubrication interval
The relubrication interval and relubrication quantity can only be precisely determined under actual operating conditions since it is not possible to calculate all the influencing factors. If the relubrication quantity cannot be determined under operating conditions, the guide values in the table should be used. The locating and non-locating bearing in the trapezoidal screw drive are lubricated for life.
Relubrication quantities per lubrication nipple
Designation | Linear ball bearing | d0 | P | Trapezoidal screw drive | Ball screw drive | ||||
|---|---|---|---|---|---|---|---|---|---|
Threaded nut | Locating bearing | Non-locating bearing | Threaded nut | Locating bearing | Non-locating bearing | ||||
≈ g | mm | mm | ≈ g | ≈ g | |||||
LTE08 | 0,2 | ‒ | ‒ | ‒ | ‒ | ‒ | ‒ | ‒ | ‒ |
LTE12 | 0,5 | ||||||||
LTE16 | 0,8 | 12 | 3 | 2 | Lubricated for life | ‒ | Lubricated for life** | ||
4 | ‒ | 0,2 | |||||||
LTE20 | 1 | 16 | 4 | 3,5 | ‒ | ||||
5 | ‒ | 0,5 | |||||||
10 | ‒ | 1,3 | |||||||
LTE25 | 2,5 | 16 | 4 | 3,5 | ‒ | ||||
5 | ‒ | 0,5 | |||||||
10 | ‒ | 1,3 | |||||||
LTE30 | 3,1 | 20 | 4 | 6 | ‒ | ||||
5 | ‒ | 0,6 | |||||||
10 | ‒ | 3,1 | |||||||
20 | ‒ | 3 | |||||||
50 | ‒ | 8,6 | |||||||
LTE40 | 5,8 | 24 | 5 | 10 | ‒ | ||||
25 | 5 | ‒ | 0,8 | ||||||
32 | 10 | ‒ | 3,1 | ||||||
20 | ‒ | 6,8 | |||||||
40 | ‒ | 9,5 | |||||||
LTE50 | 13 | 25 | 5 | ‒ | 0,8 | ||||
LTE50 | 13 | 32 | 6 | 15 | ‒ | ||||
10 | ‒ | 3,1 | |||||||
20 | ‒ | 6,8 | |||||||
40 | ‒ | 9,5 | |||||||
**If relubrication is required due to the application, please consult us.
In the case of linear tables LTE with linear ball bearings, experience shows that the initial greasing is sufficient if the following apply: normal environmental conditions, load ratio C/P ＞ 10, room temperature and v ≦ 0,6 vmax. If it is not possible to achieve these conditions, relubrication must be carried out.
For the trapezoidal and ball screw drive, a relubrication interval of 200 h to 300 h is sufficient under normal operating conditions. Relubrication must be carried out, irrespective of the result of this calculation, no more than 1 year after the last lubrication.
ATTENTION
Fretting corrosion is caused by lubricant starvation and is visible as a reddish discolouration of the rolling element raceways. Lubricant starvation can lead to permanent damage to the system and therefore to its failure. It must be ensured that the lubrication intervals are reduced accordingly in order to prevent fretting corrosion.
When calculating the relubrication interval, the grease operating life must also be checked. This is restricted to a maximum of 3 Cages due to the ageing resistance of the grease. It is the user’s responsibility to consult the lubricant manufacturer.
Relubrication procedure
Relubrication should be carried out whilst the carriage unit is moving and warm from operation over a minimum stroke length corresponding to one carriage unit length.
During lubrication, it must be ensured that the grease gun, lubrication nipple, environment of the lubrication nipple and the grease are clean.
Relubrication should be carried out wherever possible with several partial quantities at various times instead of the complete quantity at the time of the relubrication interval. Relubrication quantities, see table.
ATTENTION
The lubrication method involves loss of lubricant. The used lubricant must be collected and disposed of by methods that help to protect the environment.
The use of lubricants is governed by national regulations for environmental protection and occupational safety as well as information from the lubricant manufacturers. These regulations must be observed in all cases.
Lubrication nipples
Linear tables LTE (excluding size LTE20) are relubricated via drive fit lubrication nipples NIP A, while linear tables LTE20 are relubricated via funnel type lubrication nipples NIP to DIN 3405, ➤ Figure.
Drive fit lubrication nipple and funnel type lubrication nipple
Lubrication nipples for LTE and LTS excluding LTE20
Drive fit lubrication nipple | D | d | L | h |
|---|---|---|---|---|
mm | mm | mm | mm | |
NIP A1 | 6 | 4 | 6 | 1,5 |
NIP A2 | 8 | 6 | 9 | 2 |
NIP A3 | 10 | 9 | 12 | 3 |
Funnel type lubrication nipple for LTE20
Funnel type lubrication nipple | S h13 | d | L | h j6 |
|---|---|---|---|---|
mm | mm | mm | mm | |
NIP DIN 3405-A M6 | 7 | M6 | 9,5 | 3 |
Relubrication points
The linear ball bearings are greased in pairs in each case via a lateral lubrication nipple in the carriage unit. Each spindle nut is supplied with lubricant via a separate lubrication nipple. The spindle bearing arrangement of the ball screw drive in the shaft support blocks is supplied in each case from above via a lubrication nipple, ➤ Figure. Exception: In the case of the actuator LTE20, the spindle bearings fitted are sealed and lubricated for life.
Lubrication points on linear table
Position of relubrication points, linear tables LTE
Position of relubrication points
Designation | Mounting dimensions | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Type NIP | Without drive | With screw drive | |||||||||
2×for | 1×for spindle nut | 2×for linear ball bearings | Locating bearing | Non-locating bearing | |||||||
h56 | l56 | h56 | l56 | h57 | l57 | b77 | l77 | b78 | l78 | ||
mm | mm | mm | mm | mm | mm | mm | mm | mm | mm | ||
LTE08 | A1 | 5 | 32,5 | ‒ | |||||||
LTE12 | 6 | 42,5 | |||||||||
LTE16 | 6 | 50 | 18 | 30 | 6 | 50 | 9,5 | 10,5 | 9 | 9 | |
LTE20 | DIN** | 8 | 65 | 4,5 | 22 | 8 | 65 | 0 | 0 | 0 | 0 |
LTE25 | A2 | 8 | 80 | 5 | 53,15 | 8 | 80 | 10 | 16 | 0 | 12,5 |
LTE30 | A2 | 9 | 90 | 5 | 56,4 | 9 | 90 | 14 | 14,5 | 0 | 12,5 |
LTE40 | A2 | 9 | 115 | 5 | 56,4 | 9 | 115 | 13 | 17 | 0 | 15 |
LTE50 | A3 | 11 | 140 | 6 | 56,4 | 11 | 140 | 0 | 17 | 0 | 15 |
**Lubrication nipple DIN 3405-A M6.
**In the case of a spindle 2020 and 2050, l56 = 52 mm.
**In the case of a spindle 3210 and 3220, l56 = 86 mm. In the case of a spindle 3240, l56 = 69 mm.
**In the case of a spindle size 25, b77 = 0 mm.
**In the case of a spindle size 25, l77 = 15,5 mm.
Environments with special requirements
In vacuum applications, lubricants with low vapourisation rates are required in order to maintain the vacuum atmosphere.
In the foodstuffs sector and in clean rooms, special requirements are also placed on lubricants in relation to emissions and compatibility.
For such environmental conditions, please consult the grease manufacturer.
T-slots
The shaft support blocks of size LTE20 are designed for thin hexagon nuts in accordance with DIN EN ISO 4035, ➤ Figure.
T-slot size in shaft support block
Filling openings
The thin hexagon nuts are pushed into the T-slot on the end faces of the shaft support blocks.
Connectors for switching tags
Switching tags can be screw mounted to the linear table in order to activate switches in the adjacent construction. The position and size are dependent on the size, ➤ Figure and table.
Connectors for switching tags on actuator LTE20-A-OA
Mounting dimensions for switching tags on actuator LTE20-A-OA
Series | Mounting dimensions | ||||
|---|---|---|---|---|---|
Actuator | ⌀ P9 | Depth | |||
JL58 | l58 | h58 | D58 | t58 | |
mm | mm | mm | mm | mm | |
LTE20-A-OA | 15 | 25 | 13 | 3,5 | 12 |
Maximum permissible spindle speed
Screw drives must not be allowed to run in the critical speed range.
The critical speed is essentially dependent on the following factors:
- spindle length
- spindle diameter
- spindle bearing arrangement
- mounting method.
The carriage unit velocity v is determined from the spindle speed n and the spindle pitch P. The limit values for velocities must be observed.
For calculation of the carriage unit velocity, the following applies:
| v | m/s | Carriage unit velocity |
| n | min–1 | Spindle speed |
| P | mm | Spindle pitch. |
Diagram
The diagram shows the relationship for individual series and sizes between the critical speed and the spindle length, ➤ Figure. The diagram takes account of the effective length BL of the bellows cover.
Maximum permissible spindle speed
Influences of the adjacent construction
The running accuracy is essentially dependent on the straightness and accuracy of the fit and mounting surfaces.
The higher the requirements for accuracy and smooth running of the guidance system, the more attention must be paid to the geometrical and positional accuracy of the mounting surfaces.
Mounting position and mounting arrangement
Linear tables are suitable for numerous mounting positions and mounting arrangements.
The guidance system can be fitted with a movable or stationary linear table, ➤ Figure. The linear tables can be used in the common horizontal mounting position and also in a vertical mounting position, ➤ Figure.
Mounting of linear tables with a carriage unit to one side or suspended overhead is possible, ➤ Figure. In such cases, please consult the Schaeffler engineering service.
ATTENTION
The ball screw drives fitted in these linear tables are not self-locking. The carriage unit and load must be secured against autonomous travel or dropping if the linear tables are used in a vertical or tilted mounting position. This can be achieved, for example, by means of a brake or counterweight. The drop guard must function in manual operation as well as in motor operation, especially if the motor has no current.
Safety guidelines (especially in relation to personal protection) must be observed.
Movable or stationary carriage unit
Mounting positions
Mounting positions
Kinematic operating limits
Maximum velocities are determined as a function of the critical spindle speed, see tables. The limiting speed of the bearings can also restrict the spindle speed and thus the velocity.
Kinematic operating limits with trapezoidal screw drive
Series and size | Spindle | Maximum acceleration a | Maximum v | Maximum spindle speed n | |
|---|---|---|---|---|---|
d0 | P | ||||
mm | mm | m/s2 | m/s | min–1 | |
LTE16 | 12 | 3 | 2,5 | 0,075 | 1 500 |
LTE20 | 16 | 4 | 2,5 | 0,1 | 1 500 |
LTE25 | 16 | 4 | 2,5 | 0,1 | 1 500 |
LTE30 | 20 | 4 | 2,5 | 0,1 | 1 500 |
8 | |||||
LTE40 | 24 | 5 | 2,5 | 0,125 | 1 500 |
10 | |||||
LTE50 | 32 | 6 | 2,5 | 0,125 | 1 500 |
Kinematic operating limits with ball screw drive
Series and size | Spindle | Spindle nut design | Maximum acceleration a | Maximum velocity v | Maximum spindle speed n | |||
|---|---|---|---|---|---|---|---|---|
d0 | P | |||||||
mm | mm | m/s2 | m/s2 | m/s | min–1 | |||
LTE16 | 12 | 4 | M | ‒ | 20 | ‒ | 0,25 | 4 500 |
LTE20 | 16 | 5 | M | MM | 20 | 10 | 0,25 | 3 000 |
10 | M | ‒ | ‒ | 0,75 | 4 500 | |||
LTE25 | 16 | 5 | M | MM | 20 | 10 | 0,25 | 3 000 |
10 | M | MM | 10 | 0,75 | 4 500 | |||
LTE30 | 20 | 5 | M | MM | 20 | 10 | 0,29 | 3 500** |
10 | M | MM | 10 | 0,75 | 3 000 | |||
20 | M | ‒ | ‒ | 1,16 | 3 500 | |||
50 | M | ‒ | ‒ | 0,29 | 3 500** | |||
LTE40 | 25 | 5 | M | MM | 20 | 10 | 0,25 | 3 000 |
32 | 10 | M | MM | 20 | 10 | 0,5 | 3 000 | |
20 | M | MM | 10 | 1 | ||||
40 | M | ‒ | ‒ | 2 | ||||
LTE50 | 25 | 5 | M | MM | 20 | 10 | 0,25 | 3 000 |
32 | 10 | M | MM | 20 | 10 | 0,5 | 3 000 | |
20 | M | MM | 10 | 1 | ||||
40 | M | ‒ | ‒ | 2 | ||||
**Restricted by the limiting speed of the bearing with grease lubrication.
Mounting
In most applications, a linear table is mounted in two steps:
- location of the support rail or base plate on the adjacent construction
- mounting of the components to be moved on the carriage unit.
The support rail or base plate is screw mounted to the stationary adjacent construction using conventional fixing screws and washers. Location of the components that are to be moved with the carriage unit can be carried out using conventional fixing screws.
Interchange of linear table components
For the fitting and assembly of linear table components, a fitting and maintenance manual is available. Please consult the Schaeffler engineering service.
Maintenance
Failure to carry out maintenance, incorrect maintenance, assembly errors and lubrication errors as well as inadequate protection against contamination can lead to premature failure of linear tables.
Maintenance work is restricted in general to relubrication, cleaning and regular visual inspection for damage.
Maintenance intervals, especially the intervals between relubrication, are influenced by the following factors:
- the travel velocity
- the load
- the temperature
- the stroke length
- the environmental conditions and influences.
ATTENTION
Guidance parts relevant to function must be greased and supplied with lubricant via appropriate lubrication points.
Cleaning
If heavy contamination is present, linear tables must be cleaned in order to ensure reliable function. Suitable cleaning tools include paintbrushes, soft brushes and soft cloths.
ATTENTION
Abrasives, petroleum ether and oils must not be used.
Accuracy
Length tolerances
The length tolerances for linear tables can be taken from ➤ Figure and the table.
Length tolerances
Length tolerances for all linear tables
Total length Ltot of linear tables LTE | Tolerance | |||
|---|---|---|---|---|
mm | mm | |||
Ltot ＜ | 400 | ±0,5 | ||
400 | ≦ | Ltot ＜ | 1 000 | ±0,8 |
1 000 | ≦ | Ltot ＜ | 2 000 | ±1,2 |
2 000 | ≦ | Ltot ＜ | 4 000 | ±2 |
4 000 | ≦ | Ltot ＜ | 6 000 | ±3 |
Accuracy of the screw drive
Linear tables with trapezoidal screw drive are only available with a single nut with clearance, see table. The pitch accuracy is dependent on the size, see table.
Linear tables with ball screw drive are only available with a single nut with clearance, see table. Where higher accuracy requirements are present, preloaded (clearance-free) double nuts are possible for many pitch values, see table.
ATTENTION
In the case of standard linear tables with ball screw drive, the nut unit (double nut) can only be preloaded clearance-free if the spindle pitch P is less than the nominal diameter d0 of the spindle.
Trapezoidal screw drive
Designation | Spindle | Spindle nut | |||||
|---|---|---|---|---|---|---|---|
Nominal diameter | Pitch | Single nut | |||||
d0 | P | Accuracy | Suffix | Axial clearance | |||
|
| μm each 300 mm |
| ||||
LTE16 | 12 | 3 | 300 | M | 0,4 | to | 0,5 |
LTE20 | 16 | 4 | 50 | ||||
LTE25 | 16 | 4 | 50 | ||||
LTE30 | 20 | 4 | 50 | ||||
8 | 200 | ||||||
LTE40 | 24 | 5 | 50 | ||||
10 | 200 | ||||||
LTE50 | 32 | 6 | 50 | ||||
Ball screw drive
Designation | Spindle | Spindle nut | |||||
|---|---|---|---|---|---|---|---|
Nominal diameter | Pitch | Single nut | Double nut | ||||
d0 | P | Accuracy | Suffix | Axial clearance | Suffix | Axial clearance | |
|
| μm each 300 mm |
|
| |||
LTE16 | 12 | 4 | 50 | M | 0,05 | ‒ | ‒ |
LTE20 | 16 | 5 | 50 | M | 0,05 | MM | Preloaded |
10 | M | 0,05 | ‒ | ‒ | |||
LTE25 | 16 | 5 | 50 | M | 0,05 | MM | Preloaded |
10 | M | 0,05 | MM | Preloaded | |||
LTE30 | 20 | 5 | 50 | M | 0,05 | MM | Preloaded |
10 | M | 0,05 | MM | Preloaded | |||
20 | M | 0,05 | ‒ | ‒ | |||
50 | |||||||
LTE40 | 25 | 5 | 50 | M | 0,05 | MM | Preloaded |
32 | 10 | M | 0,05 | MM | Preloaded | ||
20 | M | 0,05 | MM | Preloaded | |||
40 | M | 0,05 | ‒ | ‒ | |||
LTE50 | 25 | 5 | 50 | M | 0,05 | MM | Preloaded |
32 | 10 | M | 0,05 | MM | Preloaded | ||
20 | M | 0,05 | MM | Preloaded | |||
40 | M | 0,05 | ‒ | ‒ | |||