Precision Target Wheel zax / zfx

ti_zax-zfx_e-1
General
  • 40 years of experience in the manufacture of precision target wheels
  • Precision target wheels for attachment to shafts with a shaft diameter from 8 mm to over 500 mm
  • Generation of a reference signal by reference mark (tooth or flag)
  • Ferromagnetic target wheels make possible contactless magnetic scanning by a sensor with magnetoresistive sensor elements and therefore the generation of the required output signals for rotational speed and position acquisition
  • Possible to manufacture target wheels for rotational speed and position acquisition using eddy currents
  • Complete manufacture with bores, threads and slots
Features
  • Number of teeth: 25 to 1024
  • Modules: 0.3; 0.5; 1.0; 1.25; 1.50; 1.75; 2.0; 2.25
  • Standard material: 16MnCr5, stainless steel optional
  • Individual inside diameter optionally with feather keyway to prevent movement in relation to the shaft
Advantages
  • Number mounting variants (shrinking, clamping, bolting in place mounting)
  • Possible to prevent movement in relation to the shaft using feather keyway
  • Multifunctional design makes it possible to use the target wheel as a bearing cover or shaft nut
  • High design flexibility due to custom manufacture
  • Highest precision due to usage of the latest hobbing machines or turning-milling centres
Field of application
  • Machine tool engineering
  • Railway rolling stock
  • Torque motors

Description

Measuring systems

For the measurement of rotary movements, rotational speed and position sensors form a unit together with target wheels. Especially on spindles for machine tools, the sinusoidal output signals are highly interpolated. To obtain optimal output signals, target wheels must be manufactured with high precision for this application. Only in this way can the output signals from the sensors be generated in the necessary quality.
High precision standard target wheels made of ferromagnetic steel with module 0.3, 0.5 and 1 are available ex-works on short delivery times.



Usage with MiniCoder GEL 2442, 2443, 2444 and 2432

MiniCoders scan target wheels with module 0.3; 0.5 or 1. Square-wave signals with 5 V DC, 10...30 V DC or 1 Vpp signals (sin/ cos-shaped track signals) are generated as output signals.
The target wheels are optionally equipped with a reference flag, a reference groove or a reference tooth. Depending on the version or position of the reference mark, a different MiniCoder variant is used to ensure a defined position for the reference signal in relation to the track signals.



Maximum rotational speed

Size, inside diameter and design of the target wheel define the strength and the maximum permitted rotational speed. In your enquiries please state the maximum rotational speed at which the related target wheel is to be used. We will then assess the feasibility.
In certain cases we undertake calculations using the FEM(1).


Module and outside diameter

Depending on the application and sensor used, target wheels with different modules are used.
The module is a tooth parameter for tooth wheels and describes the relationship between the number of teeth and the pitch circle diameter of the tooth wheel.
For the majority of applications the amount of space available is limited, here the outside diameter is crucial.
The following applies:


da = Outside diameter
m = Module
z = Number of teeth


Given the same number of teeth, the smaller the module the smaller outside diameter.


Typical rotational speed range for target wheels as a function of the inside diameter and reference mark

Number of teethz Modulem Inside diameter di [mm] Outside diameter da [mm] Reference mark, referencesignal Maximum rotational speed(a)nmax [1/min]
64 0.5 23 33 Z 90,000
64 0.3 10 19.8 Z 140,000
128 0.3 20 39 N 30,000
128 0.3 17 39 M 42,000
256 0.3 12 77.8 Z 50,000
256 0.3 50 77.8 Z 40,000
512 0.3 20 154.2 Z 18,000
512 0.3 125 154.2 Z 25,000

(a) Bores, thread, feather keyways not taken into account

Description

Reference marks

Reference marks can be designed as a tooth, groove or flag. The flag must be made of ferromagnetic material and must not protrude beyond the tip circle of the target wheel.
The selection of the reference mark is defined by the size and rotational speed of the target wheel used, as both parameters have an effect on the forces acting on the reference mark. In case of new designs we recommend the usage of a target wheel with reference mark variant "Z".


ti_zax-zfx_e-3_03


ZAN / ZFN
= Reference mark - flag


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ZFM
= Reference mark - groove


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ZAZ / ZFZ
= Reference mark - tooth

Identifier

Depending on the reference mark, target wheels have the following item numbers as identifiers:


Standard target wheels

ZANxxxx    Reference mark as flag (reference flag is between
		   two teeth)
ZAZxxxx     Reference mark as tooth (reference tooth is
		   aligned with a tooth)

Custom target wheels

ZANxxxx    Reference mark as flag (reference flag is between
		   two teeth)
ZAMxxxx    Reference mark as groove (reference groove is
		   between two teeth)
ZAZxxxx     Reference mark as tooth (reference tooth is
		   aligned with a tooth)

The target wheels are marked with item number and serial number.

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Standard target wheels

Available ex-works on short delivery times

Type Code ti_zax-zfx_e-4_03



Dimensional drawing standard target wheels with reference mark tooth - ZAZ

ti_zax-zfx_e-4_06



Design of standard target wheels ZAZ


Number of teethz Modulem [mm] Outside ø da [mm] Inside ø di min [mm] Inside ø di max. [mm] Shoulder ø dr [mm]
100 0.5 51.0 12 H7 30 H7 48
125 0.5 63.5 12 H7 40 H7 60.5
128 0.5 65.0 12 H7 40 H7 62
200 0.5 101 12 H7 70 H7 98
256 0.5 129 12 H7 90 H7 126
250 0.3 75.6 12 H7 45 H7 72.6
256 0.3 77.4 12 H7 50 H7 74.4
360 0.3 108.6 12 H7 70 H7 105


Standard target wheels

Available ex-works on short delivery times


Dimensional drawing standard target wheels with reference mark flag - ZAN

ti_zax-zfx_e-5_03



Design of standard target wheels ZAN


Number of teethz Modulem [mm] Outside ø da [mm] Inside ø standard [mm] Inside ø di max. [mm] Shoulder ø dr [mm]
100 0.5 51.0 12 H7 30 H7 47
125 0.5 63.5 12 H7 40 H7 60
128 0.5 65.0 12 H7 40 H7 61
200 0.5 101.0 12 H7 70 H7 97
250 0.3 75.6 12 H7 45 H7 72
250 0.5 126.0 25 H7 85 H7 122
256 0.3 77.4 12 H7 50 H7 74
256 0.5 129.0 25 H7 90 H7 125
360 0.3 108.6 25 H7 70 H7 105
500 0.3 150.6 25 H7 110 H7 147
512 0.3 154.2 25 H7 110 H7 151


Custom target wheels



Upon customer request Lenord + Bauer will manufacture your target wheels to your specific requirements. Please send us a design drawing of your target wheel (if possible as a dxf file) toinfo@lenord.de.


Assembly

Shrinking

With this method the target wheel is not manufactured to exactly fit the shaft, instead the inside diameter is made slightly smaller. The target wheel cannot be fitted to the shaft at normal temperatures. By heating the target wheel the material expands and can be pushed onto the shaft. As the target wheel cools it shrinks and is pressed firmly onto the shaft.

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Bolting to shaft shoulder

The target wheel is pushed onto the shaft and fastened to the shaft shoulder using screws.

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Clamping via shaft nut

The target wheel is pushed onto the shaft and pressed against this component using a shaft nut. Upon request the target wheel can also be equipped with an integrated shaft nut, for this purpose a corresponding thread is cut on the inside diameter.

ti_zax-zfx_e-7_03  Prevention of movement in relation to the shaft

For special applications feather keyways on the inside diameter of the target wheel provide protection against twisting.