THE MEASUREMENT OF SURFACE TEMPERATURES · PDF file · 2016-11-08THE MEASUREMENT OF SURFACE TEMPERATURES ON GEAR TEETH DURING HIGH SURFACE PRESSURE WITH DISSIMILAR HARDENED GEARS

THE MEASUREMENT OF SURFACE TEMPERATURES ON GEAR TEETH

DURING HIGH SURFACE PRESSURE WITH DISSIMILAR HARDENED GEARS

*Takuya Goto (Kindai University)

*Yasuyoshi Tozaki (Kindai University)

*Naoya Matsushita (Kindai University)

*Yuji Sumitani (Kindai University)

Novenber 4, 2016

Outline1. Background

2. Targets

3. Calibrated test of thermoelectromotive force

4. Measuring test of surface temperatures on gear teeth

5. Comparison of theoretical formula and experimental values

6. Conclusion

1. Background

Power transmission systems using gears require both large capacity and miniaturization. As a result, the gears used in power transmission need to be strong enough to withstand high loads and high engine speeds.

Gear operation with high loads and at high engine speeds produces a large amount of heat in gear meshing areas, which leads to scoring and other frictional damage to surfaces on gear teeth.

A close relationship exists between this and surface temperatures on gear teeth.

The precise measurement of surface temperatures on gear teeth is important.

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1. Background

Freezing point

Meshing point

Electric potential difference

Different metals

Dynamic thermocouple

2/17

Previous studies have shown that it is possible to measure surface temperatures on gear teeth with the dynamic thermocouple and the combined lacked gear.

The dynamic thermocouple is to measure surface temperatures on gear teeth using the gears as a thermocouple.

1. Background

Insulating plate

Gear B

Gear A

Insulating bolt

Insulating nut

Combined lacked gear

The combined lacked gear enables us to measure surface temperatures of each tooth in double contact area.

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The combined lack gear consists of two gears and insulating plate alternately lacking teeth as shown in Fig. 9, wherein a gear with a boss is the side A gear, and a gear without a boss is the side B gear.

1. Background

On the study using dynamic thermocouple and combined lacked gear by Yokoyama, Ishikawa, and Hayashi in 1971

The experiments were operated on maximum condition of contact pressure 980MPa in a pitch point.

They used that the drive gear was carburized steel and the driven gear was hard Nickel electro-deposited steel.

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2. Objective

(1) The experiment is operated on maximum (1) condition of contact pressure 1.5GPa in a (1) pitch point.

(2) We use the gears of two simple ferrous (2) (2) metals which are plasma carbonized SUS316 (2) and induction hardened S55C.

In the measurement of surface temperatures on gear teeth

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2. Targets




6. Conclusion

3. Calibrated test of 3. Thermoelectromotive force

The purpose of this study is to use dissimilar metals to measure surface temperatures on gear teeth with a dynamic thermocouple. In order to measure actual surface temperatures on gear teeth, a thermoelectromotive force – temperature conversion formula needed to be constructed according to the gear materials.

We preform thermoelectromotive force calibration tests, and then constructed a thermoelectromotive force –temperature conversion formula for a combination of plasma carburized SUS316 and induction hardened S55C.

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Plasma carburized SUS316 Induction hardened S55C

S60Cwire

Heater

Water

Ice bathOil

Thermometer

Slip ring

SUS316wire

TesterTest overview

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Test results

0.00.10.20.30.40.50.60.70.80.91.0

270 280 290 300 310 320 330 340 350 360 370

The

rmoe

lect

rom

otiv

e fo

rce

Vm

V

Temperature T K

Thermoelectromotive force

The graph is verified that the relationship of thermoelectromotive force and temperature in plasma carburized SUS316 and induction hardened S55C is linearly proportional.

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A thermoelectromotive force – temperature conversion formula (1) was derived for combinations of plasma carburized SUS316 and induction hardened S55C, assuming the thermoelectromotive force to be V [mV] and the connection temperature to be T [K].

0.00.10.20.30.40.50.60.70.80.91.0

270 280 290 300 310 320 330 340 350 360 370

The

rmoe

lect

rom

otiv

e fo

rce

Vm

V

Temperature T K

Thermoelectromotive force

𝑇 = 101𝑉 + 𝐶 𝐾 ・・・ (1)

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2. Targets




6. Conclusion

Plasma carburized SUS316 combined lacked gear

Induction hardened S55C gear

4. Measuring test of 4. surface temperatures on gear teeth 3.

Test gears

Plasmacarburized

SUS316 gear(Drive gear)

InductionhardenedS55C gear

(Driven gear)Module

Pressure angle (deg)Number of teeth 20 (10×2) 20

Top diameter (mm)Pitch diameter (mm)

5

110100

20

Dimension of test gears

We use plasma carburized SUS316 gear as drive gear and induction hardened S55C gear as driven gear. The

plasma carburized SUS316 gear is combined lack gear.

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The test conditions consisted of a total of 16patterns with input rotating speeds of 6, 20, 40 and 60 rpm, and torques of 5, 10, 15 and 20 N·m.

Test condition

11/174. Measuring test of 4. surface temperatures on gear teeth 3.

Test device is driven by a geared motor and provides torque to gears with a powder brake. Using a plasma carburized SUS316 combined lacked gear for the drive gear, an induction hardened S55C gear for the driven gear, it fully insulates the side A gear and side B gear of the plasma carburized SUS316 combined lacked gear, uses the slip ring attached to the shaft end to remove thermoelectromotive force from the rotor, and measures it with a data recorder.

Test device

Slip Ring

Slip Ring

Motor

Brake

Induction hardenedS55C gear

Plasma carburized SUS316 gear

Ice bathData

RecorderRevolution indicator

Ceramic ball bearing

Torque meter

SUS316 gear A

SUS316 gear BPlastic coupling

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The purpose of this study is testing at high surface pressure that is approximately 1.5 GPa. This could not be achieved with torques of 20 N・m.

We crowned a plasma carburized SUS316 combined lacked gear to achieve target surface pressure. maximum contact pressure was determined by Hertzianelastic contact theory. A crowning curvature of 42.5 mm or less was obtained in order to achieve target surface pressure that is 1.5 GPa.When we measured the crowning curvature of the plasma carburized SUS316 combined lacked gear after crowning, it was 46.4 mm, and the maximum contact pressure was 1.46 GPa.

Crowning

0.00.51.01.52.02.53.03.54.0

0 20 40 60 80 100Cont

act

pre

ssure

GPa

Crowning curvature mm

20N・m

0.42GPa

Straight

20N・m

1.46GPa

Crowning

42.5mm

10mm

46.4mm

High pressureLow pressure

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Test results

250270290310330350

2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0

Tem

per

atu

re K

Time sec

250270290310330350

2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0

Tem

per

atu

re K

Time sec

double contact area

1 cycle

Root

Pitch point

Top

1 cycle

Gear B

Gear A

The elevated surface temperatures on gear teeth clearly appears at the tooth tip, pitch point and root. It is believed that surface temperatures on gear teeth during high surface pressure was successful. Only part of double contact area was seen, and the cause needs to be further investigated.

Rotating speed 60rpm, Torque20N・m

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2. Targets




6. Conclusion


Formula of Blok

bcc

vvPn

)(83.0

2221111

21

max

＋

𝜇 = 0.01 2.5𝑙𝑜𝑔𝐷 + 3.5μ ： Friction coefficient of gear meshingμ： pointD : lubrication state

𝐷 = 𝑅𝑧1 + 𝑅𝑧2 ℎ𝑚𝑖𝑛

D : Lubrication stateRz∶ The maximum height roughness[μm]hmin∶ Minimum oil film thickness[mm]

θ ： Elevated temperature[K]

Pn : Unit normal load[N/m]ν : Periphral speed of gearν : meshing point[m/s]λ : Thermal conductivity[W/(mK)]γ :Density[kg/m3]c : Specific heat[J/(KgK)]b : Half contact width[m]

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Theoretical values Experimental values

When we compared the experimental and theoretical values, the elevated surface temperatures on gear teeth values were largely the same. Consequently, it is felt that the experimental values obtained from the surface temperatures on gear teeth measuring test were accurate.

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2. Targets




6. Conclusion

6. Conclusion

(1) During high surface pressure which is (1) 1.46 GPa.

(2) By using the gears of two simple ferrous (2) metals which are plasma carbonized (2) (2) SUS316 and induction hardened S55C.

We could measure surface temperatures on gear teeth successfully

Comparison of the experimental and theoretical values of flash temperature were largely the same.

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This work was supported by Grant-in-Aid for Scientific Research (C) 15K05774

THE MEASUREMENT OF SURFACE TEMPERATURES · PDF file · 2016-11-08THE MEASUREMENT OF SURFACE TEMPERATURES ON GEAR TEETH DURING HIGH SURFACE PRESSURE WITH DISSIMILAR HARDENED GEARS

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