Lead Screw Nut

The Lead Screw Nut Models DCM and DC are manufactured to meet the standards for 30° trapezoidal threads. The nut is made of a special alloy and die-cast with a precision male thread as its core. As a result, these bearings achieve greater stability in accuracy and higher accuracy and wear resistance than machined lead screw nuts.
For the screw shafts to be used with this product, rolled shafts are available as the standard.
In addition, cut screw shafts are also available according to the application. Contact THK for details.

Types

Highlight feature tags

  • Wear resistance
  • Flanged type
  • Cylindrical type
Model DCM
  • Flanged type
  • Wear resistance
Model DC
  • Cylindrical type
  • Wear resistance

Features

Structure and Features

The lead Screw Nut models DCM and DC are manufactured to meet the standards for the 30° trapezoidal threads. They use a special alloyHigh Strength Zinc Alloy(see) for the nuts and have a precision male thread, formed through die casting, as the core. As a result, these bearings achieve less unevenness in accuracy and higher accuracy and wear resistance than the machined lead screw nuts.For the screw shafts to be used with this product, the rolled shafts are available as the standard. In addition, cut screw shafts are also available according to the application. Contact THK for details.

Features of the Special Rolled Shafts

The dedicated rolled shafts with the standardized lengths are available for the Lead Screw Nut.

Increased Wear Resistance

The shaft teeth are formed by cold gear rolling, and the surface of the tooth surface is hardened to over 250 HV and are mirror-finished. As a result, the shafts are highly wear resistant and achieve significantly smooth motion when used in combination with lead screw nuts.

Improved Mechanical Properties

Inside the teeth of the rolled shaft, a fi ber fl ow occurs along the contour of the tooth surface of the shaft, making the structure around the teeth roots dense. As a result, the fatigue strength is increased.

Additional Machining of the Shaft End Support

Since each shaft is rolled, additional machining of the support bearing of the shaft end can easily be performed by lathing or milling.

High Strength Zinc Alloy

The high strength zinc alloy used in the lead screw nuts is a material that is highly resistant to seizure and the wear and has a high load carrying capacity. Information on mechanical properties,physical properties, and wear resistance is presented below.

*The figures shown are target values—these figures are not guaranteed.

Mechanical Properties

Table1

Item

Description

Tensile strength 275 to 314 N/mm2
Tensile yield strength (0.2%) 216 to 245 N/mm2
Compressive strength 539 to 686 N/mm2
Compressive yield strength (0.2%) 294 to 343 N/mm2
Fatigue strength 132 N/mm2×107(Schenk bending test)
Charpy impact 0.098 to 0.49 N・m/mm2
Elongation 1 to 5 %
Hardness 120 to 145 HV

Physical Properties

Table2

Item

Description

Specifi c gravity 6.8
Specifi c heat 460 J/(kg・K)
Melting point 390 ℃
Thermal expansion coeffi cient 24×10-6

Wear Resistance

Table3 [Test conditions: Amsler wear-tester]

Item

Description

Test piece rotational speed 185 min-1
Load 392 N
Lubricant Dynamo oil