Market Information MAI 67

Combination Thrust and Radial Bearings with Integrated Measuring SystemSeries YRTM/MEKO

Features

The measuring system integrated in series YRT combination thrust and radial bearings allows the non-contact, magnetoresistive recording of angles within the range of a few angular seconds.It consists of:■ an INA combination thrust and radial bearing,

series YRTM with a dimensional scale– the dimensional scale consists of several metallic layers.

The layers are electo-plated onto the YRT-bearing shaft washer.

■ the MEKO electronic measuring system, consisting of two measuring heads and an electronic evaluation device– the measuring heads have magnetoresistive sensors

and are diametrically integrated into the mounting structure

– the electronic evaluation device uses vector addition to calculate the value of the effective angle from the two sensor signals and then converts this value to a 1 Vpp value

Advantages of the INA Angle Measuring SystemThe measuring system offers the following advantages:■ Non-contact operation and thus wear-free■ Measurements not dependent on tilting or position■ Self-adjusting electronics■ Self-centering■ Not affected by vibration■ Not affected by lubricants■ Easy to install; measuring heads are easy to adjust

– no alignment of bearings or separate measuring system necessary

■ Compatible with conventional angle measuring systems available on the market

■ Requires no additional components (housing and shaft design)– the dimensional scale and measuring heads are

integrated in the bearing and the mounting structure– the design space saved can be used for the machine

work area■ Supply leads pose no problems

– leads can be placed inside the mounting structure, through the bearing bore

■ Requires fewer components■ Compact, integral design with fewer components is

cost effective and allows overall design space savings

Please refer to INA brochure GKL for relevant technical data on YRT combination thrust and radial bearings.

Thrust/Radial Bearings w/ Measuring System+

_

˚C

■ for bearings with bore diameters of 180 mm, 200 mm, 260 mm, 325 mm and 395 mm

■ suitable for temperatures from 0 °C to +70 °C

■System Measuring Principle

■ ➀ magnetic scale■ ➁ magnetic flux lines■ ➂ measuring head with magnetoresistive sensor■ ➃ electronic evaluation device■ ➄ analog signals at output

MEKO .../...

107

372

+1V

–1V

3

1 2

4

5

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2

Combination Thrust and Radial Bearings with Integrated Measuring SystemProduct Description

Dimensional ScaleMagnets with high-precision encoders are positioned 250 �m apart on the magnetizable electro-plated coating and serve as angle references (Figure 1). A sharply defined magnetic field is measured between the poles of the magnets.

Reference MarksThe magnetoresistive dimensional scale allows incremental angle measurement. However, since an absolute reference is needed to determine the positions, another track is furnished in addition to the incremental track. This track has reference marks. These reference marks must be passed to produce an absolute reference. The INA angle measuring system has distance-coded reference marks every 15° so the system can easily move to the reference (Figure 1). The absolute reference is present as soon as two adjacent reference marks are passed.

Measuring Heads with Magnetoresistive SensorsBoth measuring heads are optimized in terms of design space (Figure 2). They are secured in a slot in the mounting structure by a mounting screw.The magnetoresistive (MR) effect allows the small magnetic fields to be detected. Unlike magnetic heads, the MR sensors perform static measurements on magnetic fields, i.e. electrical signals are derived without motion.The resistive coating of the MR sensors is designed so that the resistance changes when a magnetic field is applied perpendicular to the current flow. The magneto-sensitive coatings are specially arranged to ensure that:■ external influences – e.g. temperature fluctuations –

are almost completely compensated■ two optimum electrical signals are always available at

the same timeTwo sinusoidal signals with a phase shift of 90° and a cycle length of 500 �m are generated when the magnetic scale moves past the MR sensor. This coupling is used to measure the angle.

Figure 1 · Dimensional scale

Figure 2 · Measuring head with magnetoresistive sensor

S-

15˚

�25

0m

N+

107

374

MEKO .../...

107

375

3

Electronic Evaluation DeviceThe electronic evaluation device (Figure 3) operates with the aid of a digital signal processor (DSP):■ the MR sensor input signals are digitized by an analog-to-

digital converter■ the high-performance processor (DSP) automatically adjusts

the sensor signals and uses vector addition to calculate the effective angle value from the sensor signals– factors such as the analog-signal offset are corrected

■ a digital-to-analog converter generates synthetic analog signals as a 1 Vpp value

The electronic evaluation system can be placed anywhere on or inside the mounting structure. It is connected to the control system by a conventional 12-pin extension cable.

Output SignalsIncremental signals A and B are phase-offset by 90° and have an output level of approx. 1 Vpp. The reference mark signals, applied at 15° intervals, have an effective value of around 0.5 V.Leads of up to 100 m in length can be used to transmit the voltage signals from the electronic evaluation device to the downstream electronic system.The supply voltage is 5 V �10%.

Signal Transmission CablesThe measuring system components have polyurethane (PUR) cables that are resistant to oils, hydrolysis and microbes in accordance with VDO 0672.The bending radii R will vary depending on the cable diameter (Table 1).

Plug ConnectionsINA plug connections are robust and designed for use in an industrial environment. When plugged in, they comply with protection class IP 65 (EN 60 529). The large sheathed areas in the plugs reliably shield the cable connection between the measuring system and the downstream electronic system.

Figure 3 · Electronic evaluation device

Table 1 · Bending Radii R

Cable Cable Diameter Bending Radius for Single Bending

Bending Radius for Alternate Bending

Ømm

Rmm

Rmm

Measuring head 5.5 �20 � 80

Lead 8 �40 �100

107

376

4

Combination Thrust and Radial Bearings with Integrated Measuring System

Product Description

Measuring AccuracyThe more accurate the angle measurement, the more accurately a shaft can be positioned. The accuracy of angle measurement is mainly determined by the following:■ Quality of ruled grid distribution ➀ ■ Scanning quality ➁ ■ Quality of the electronics for signal processing ➂ ■ Pitch eccentricity with respect to the bearing arrangement ➃ ■ Radial runout deviation of the bearing arrangement ➄ ■ Elasticity of the measuring system shaft and its coupling to

the shaft to be measured ➅ ■ Elasticity of the stator shaft or shaft coupling ➆Only ➀ to ➂ are relevant for the INA YRTM measuring system.The eccentricity in ➃ is completely eliminated by the diametric arrangement of the MR sensors. ➄ to ➆ above play only a minor role in the measuring system.

Accuracy deviationsThe measuring system can detect two types of deviations:

■ Positional deviations during a rotation– these deviations are the absolute measurement errors in

one system rotation. They apply at an ambient temperature of +20 °C and a rotation speed of 5 rpm.Deviations:YRTM 180 ��5�YRTM 200, YRTM 260, YRTM 325, YRTM 395 ��3�

■ Positional deviation during a signal cycle– this deviation is less than 1%.

This is equivalent to a positioning deviation of ��3�

Because the system’s dimensional scale is linked to the rolling bearing directly – without any compensating elements – bearing displacements and eccentricities can affect the measuring results. However, this effect does not occur here because of the diametric sensor arrangement. The electronic evaluation device always uses vector addition to obtain the effective measurement value from both signals.

Measurement recordAn accuracy record is included with each INA measuring system (Figure 4). Accuracy is measured and recorded on the coded washer of the YRT bearing when the coding is applied. The measurement record indicates the coding pitch error.

Figure 4 · Sample measurement record for an INA angle measuring system

MEKO 260 S.Nr. 32432984INA Wälzlager Schaeffler oHGD 91074 Herzogenaurach-

Tel. (09132) 82 0-

Bearing:Line count:Max. angular deviation:Number of measuring points:

YRTM2160

1.8"±2160

Manufacturer's inspection certificateInspector:Accuracy grade:

Normal:3.0"+-

RON786

Measurement travel in ˚

Varia

tion

in "

10

8

6

4

2

0

10

8

6

4

2

-

-

-

-

-450 90 135 180 225 270 315 360

260

FW/16.04.99

107

379

5

Possible Sources of Electrical Interference during Signal TransmissionInterference voltages are mainly generated and transmitted by capacitive or inductive interference. Interference can occur through lines as well as from equipment inputs and outputs. Sources of interference include:■ Strong magnetic fields from transformers and electric

motors■ Relays, contactors and solenoid valves■ High-frequency equipment, pulse equipment and magnetic

stray fields from switched-mode power supply units■ Supply mains and leads to the equipment mentioned above

Safety InformationNever use YRTM bearings to locate dial gages etc.Magnetic fields will damage or erase the dimensional scale. This will result in incorrect system measurements that are displayed as an error message in the control.The measuring system should be designed so that operation is not affected by electrical or mechanical sources of interference.INA cables or suitable, commercially available cables should be used as signal lines.

Sample Order and Order Code DesignationA unit always consists of:■ Series YRTM combination thrust and radial bearing with

dimensional scale■ MEKO electronic measuring system The electronic

measuring system includes two measuring heads and an electronic evaluation device.

ExampleOne unit comprising:■ a series YRTM combination thrust and radial bearing for

a bore diameter of 260 mm■ a MEKO electronic evaluation system 260Order code designation: 1 pc. YRTM 260

1 pc. MEKO 260

Angle Measuring Device – Technical DataTechnical data for the angle measuring device are provided in Table 2.

Table 2 · Technical Data

Data

Voltage supply 5 V �10%/max. 200 mA (zero load)

Scale magnetically hard electro-plated coating with periodic North-South pitch

Incremental signalsLine count/accuracy (at +20 °C)

Reference marks Limit frequency (–3 dB)

�1 VppYRTM 180 3 072/�5�YRTM 200 3 408/�3�YRTM 260 4 320/�3�YRTM 325 5184/�3�YRTM 395 6 096/�3�distance-coded every 15°�180 kHz

Data interface –

Recommended measurement step 0.0001°

Operating temperature from –0 °C to +70 °C

Protection class (EN 60 529) IP65

WeightMeasuring headsElectronic evaluation device

130 g each520 g

Electrical connectionsMeasuring heads

Downstream electronic system(not included)

with: 2 m PUR cable Ø 5.5 mm with plug Ø12 mmwith: 12-pin flanged plug, Ø28 mm

Permissible length of cable to downstream electronic system

max. 100 m

6

Combination Thrust and Radial Bearings with Integrated Measuring System

Installation

The complete angle measuring system is very easy to install, because the arrangement of the dimensional scale is compact, and the measuring heads are small and designed for optimum design space.

Checking the Mounting Structure

Always ensure that:■ the slots for the measuring heads are made within

the specified dimensions (Table, Page 11)■ the recess DA min (Figure 5, Table 3) is integrated in

the mounting structure for bearing installation and reliable measuring system operation

■ distance F (Figure 6, Table 3) is observed after measuring head installation. When installed, the measuring heads must be centered with respect to the shaft-washer height

Installing Combination Thrust and Radial BearingsDuring installation, the high-precision shaft journal centers the coded shaft washer over the entire bearing height. If holes in the shaft washer are offset with respect to the bearing inner ring, loosen the retention screws and manually rotate the shaft washer to the correct position.

Metal tools or magnetized tools must not be used.The installation instructions for series YRT combination thrust and radial bearings given in the INA publication TPI 103 should also be followed.

Figure 5 · Recess diameter DA min

Figure 6 · Distance F

Table 3 · Recess diameter DA min and Distance F

Combination Thrust and Radial BearingsDesignation

Recess Diameter Distance

DA minmm

Fmm�0.1

YRTM 180 245.5 10

YRTM 200 272 10

YRTM 260 345 11.8

YRTM 325 416 12.5

YRTM 395 486.5 13.8

D A min

107

396

F

107

397

7

Installing Measuring HeadsThe installation position for the measuring heads is identified with an arrow (see top figure on page 1). The heads should always be installed with the arrow tip pointing to the mounting face of the bearing outer ring.Set measuring heads between 0.02 mm and 0.1 mm from the shaft washer outside diameter (Figure 7) using the adjusting foils ➀ provided.

The diametric arrangement of the measuring heads must not vary by more than 180° �1°.Use only demagnetized tools to make adjustments.Secure the measuring-head mounting screws ➁ using Loctite.

The measuring heads have been factory-adjusted to the electronic evaluation device. Further adjustment is not necessary during mounting. Care has also been taken to ensure that the permissible positional deviation is not exceeded during a signal cycle.A seal ➂ can be integrated in the mounting structure (Figure 7).

Setting and Diagnostics ProgramAn optional evaluation program can be used to facilitate the adjustment of the measuring heads. This program can be used both for mounting and the functional diagnosis of the installed measuring system.

Connecting Signal-Transmission Cables and PlugsA 2-meter cable with plug is attached to each measuring head. The cables can be routed through the mounting structure through a 13-mm-diameter hole.

Measuring heads, plugs and cables should be protected from mechanical damage.The measuring system should be grounded with a short cable to prevent interference.

Input-signal plugs for the electronic evaluation system are equipped with 7 or 8 pins and are color-coded. Connect the 7-pin and 8-pin plugs to the appropriate jacks on the MEKO box.

Figure 7 · Measuring head installation

Figure 8 · Dimension A – distance between sensor and shaft washer

1

1

0,02 mm to 0,1 mm

2

3

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A

D

YRTM

M

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8

Combination Thrust and Radial Bearingsdouble direction

Series YRTM

YRTM

J

J

D

D

Hd

ad

d D

d

CH

H

1

M

M3

1

1

1

2

107

369

1) Including retention screws or threaded extraction holes.2) Tightening torque for screws to DIN 912, quality class 10.9.3) MRL at nconst = 5 rpm.

When designing the drive, a starting torque between 2 and 2.5 times MRL must be taken into consideration.4) Rigidity values take rolling element set, bearing ring deformation and the screw connection into account.5) The read head cannot be mounted between the fixing holes or the mounting screw heads.

This leaves two unused holes for the mounting screws in the bearing outer ring.6) Note: H is 1 mm higher than standard series YRT bearings.

Dimension Table · Dimensions in mm

Bearing borediam-eter

Designation Weight Dimensions Locating holes Retention screws

d D H H1 HM C DM D1 J J1 Inner ring Outer ring Number

�kg

d1 d2 a Number d3 Number

180 YRTM 1805) 7.7 180 280 446) 30 10 15 244.5 244 194 260 7 11 6.2 46 7 45 2

200 YRTM 2005) 9.7 200 300 45 30 10 15 271.2 274 215 285 7 11 6.2 46 7 45 2

260 YRTM 260 18.3 260 385 55 36.5 13.5 18 343.8 345 280 365 9.3 15 8.2 34 9.3 33 2

325 YRTM 325 25 325 450 60 40 15 20 412.6 415 342 430 9.3 15 8.2 34 9.3 33 2

395 YRTM 395 33 395 525 65 42.5 17.5 20 485.5 486 415 505 9.3 15 8.2 46 9.3 45 2

9

Hole pattern

Retention screws

t

G

107

121

Mounting structure requirements

Threaded extraction holes

Pitch t1) Screw tightening torque

Load ratings Fatigue limiting load

Limiting speed

Bearing frictional torque3)

Axial rigidity4)

Radial rigidity4)

Tilting rigidity4)

Bearing borediam-eterG Number Number�t axial radial axial radial

MA2))

Nm

dyn.CkN

stat.C0kN

dyn.CkN

stat.C0kN

Pu

kN

Pu

kN

nG

rpm

MRL

Nm

caL

kN/�m

crL

kN/�m

ckLkNm/mrad

M8 3 48� 7.5° 14 92 580 83 209 56 23.3 190 12 2.2 3 17 180

M8 3 48� 7.5° 14 98 650 89 236 61 25.5 170 14 3 3.5 23 200

M12 3 36�10° 34 109 810 102 310 71 31 130 20 5.5 4.5 45 260

M12 3 36�10° 34 186 1 710 134 415 131 38.5 110 40 8.5 5 80 325

M12 3 48� 7.5° 34 202 2 010 133 435 146 43.5 90 55 12.5 6 130 395

107

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//// 2 A

3

2 C

3

B

C

0,80,8

0,80,8

0,80,8d h5h5

JS7JS7

0,80,8

2 B

A

107

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10

MEKO Electronic Measuring DeviceElectronic Components

Plug configuration of 12-pin flanged plug

1

2

3

4 5

6

7

89

10

11

12

107

383

The sensor cables are connected internally with the supply cables.The housing is shielded.

Plug Configuration of 12-pin Flanged Plug

5 6 8 1 3 4 12 10 2 11 9 7 /

A B R 5 V (UP) 0 V (UN) 5 V (sensor)

0 V(sensor)

not assigned

/ not assigned

+ – + – + – – – – – – – –

– – – – – – IEC 747 EN 50 178 – – – – –

�53

Ø12

R20Bending radius

Protection class IP65

Ø10.5

Ø5

612

Ø5.5

Ø13

B

16

5.75

22

15.9 -0.1

Design type B

MEKO 200

MEKO 260/395

MEKO 180/325

20

25

22.5

4032

17.5

R8

Measuring head with magnetoresistive sensor

107

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11

Mounting structure with cable opening without cable opening

80

25 25

45 4514.5M5 10 mm deepØ13

Ø14 Ø14

Ø16

R8 R8

+1.0 70 +1.0

+1.0 M5 10 mm deep

Center line+0.1 Ø16 +0.1

±0.1 ±0.1 14.5±0.1±0.5

16.2 min. 13

12

+0.1

+0.5

0.02 to 0.1mmgap

a

A

–0.4

b

Design type AYRTM 180 144.7YRTM 200 155.6

YRTM 395 267.7YRTM 325 228.8YRTM 260 196.9

107

384

a

b

�57

�49 125

74

59

Not included

Protection class IP65

14

80

2230

92

12 9 3

24

3150.3

125113

22.3

9

52

14

40

Ground terminal M4

5715

24

23

Ø8 Ø4.822

Hole for 2� mounting screwDIN 912-M4�20

ø8

Electronic evaluation system

107

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Sac

h-N

r. 00

5-29

8-89

0/M

AI 6

7 U

S-D

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INA Wälzlager Schaeffler oHG91072 Herzogenaurach (Germany)Telephone (+49) 9132 82-0Fax (+49) 9132 82-49 50www.ina.com