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Nut Cooling Ball Screws Change of screw shaft temperature

■ Cooling effects Increase in temperature, Test conditions: No cooling

By optimizing the cooling structure inside the nut, the Specimen; Shaft dia. 50 mm,
increase in temperature in the screw shaft is comparable Lead 25 mm
to shaft cooling. Moreover, the screw shaft and ball nut
can be cooled at the same time for even more precise Coolant; Oil
temperature control. Coolant flow rate; 3 L/min
The nut in contact with the table is cooled, so that heat
conduction from the ball screw to the table is blocked. Shaft and nut Nut cooling Shaft cooling
cooling

Time, hour

Nut cooling No cooling

Test table appearance Temperature distribution with nut cooling Temperature distribution without cooling

■ Internal design in consideration of preload torque change

The nut cooling ball screw has double contact-point preload in the tensile direction. This prevents an increase in preload
torque when the nut is cooled, enabling an effective cooling of the ball screw.

■ Improved handling

Ball screw cooling is achieved by attaching piping to the outer periphery of the nut flange. No sliding seals or rotary
joints are required. Dimensions for mounting area are identical to the HMD series ball screws for high speed machine
tools, so the nut cooling can be implemented without changing machine designs. Please contact NSK for application to
other types of ball screws.

Nut cooling for HMD Series Applicable dimensions for HMD Series Unit: mm

4-through hole Rc1/8 45 22.5 45 Rc1/8 Model No. Shaft dia. Lead D1 D2 H L1 Nut dimensions W X Y Z
(for coolant) (for coolant) 22.5 (for coolant) d l L2 L3 L4 L5

EM4016-4E 16 166 140.5 7.5 18

6-øX drill thru EM4020-6E 40 20 86 128 96 156 130.5 7.5 18 18 106 11 17.5 11
øY c’bore, Z depth EM4025-6E 25 188 162.5 7.5 18

D1 g6 PCD W EM4030-6E 30 219 193.5 7.5 18
d
D2 EM4516-4E 16 166 140.5 7.5 18

EM4520-6E 45 20 92 134 102 156 130.5 7.5 18 18 112 11 17.5 11

EM4525-6E 25 188 162.5 7.5 18

EM5016-4E 16 166 140.5 7.5 18

L3 22.5 EM5020-6E 50 20 98 140 107 156 130.5 7.5 18 18 118 11 17.5 11
L2 L4 L3 45 EM5025-6E 25 188 162.5 7.5 18
L1 45 Rc1/8
(oil hole) EM5030-6E 30 219 193.5 7.5 18
Option symbols ‘NC’ are included in the assembly part number.
Example: W4012-123ZMNCX-C5Z20 H EM6316-4E 63 16 122 180 138 176 139 9 28 28 150 18 26 17.5

■ Operating suggestions

If heat impact from the bearing is too great, separate cooling for bearing and surrounding areas is recommended.
For details, please contact NSK.

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