CN105136322A - Temperature measuring method of tooth root of gear - Google Patents

Abstract

The present invention discloses a temperature measuring method of a tooth root of a gear. The temperature measuring method of the tooth root of the gear comprises two steps: preembedding a thermocouple and calculating a transient temperature of a tooth surface. According to the invention, the temperature of the tooth root is detected, and the transient temperature of the meshing tooth surface is indirectly calculated so as to provide a very valuable reference for the gear design. In the traditional gear temperature detection design, the average temperature of the gear is only considered, and the transient temperature of the meshing tooth surface is neglected, wherein the transient temperature of the meshing tooth surface is a direct factor resulting in gluing burning of the gear, and moreover, particularly about a high speed heavy load gear, the transient temperature of the meshing tooth surface is particularly important. According to the invention, the problem of how to obtain the transient temperature of the meshing tooth surface of the gear is solved.

Description

A kind of Gear Root thermometry

Technical field

The present invention relates to gear testing technical field, particularly relate to a kind of Gear Root thermometry.

Background technology

The measuring method of existing gear temperature comprises infrared thermography method, the oil temperature indirect method of measurement etc., but all has certain limitation.Infrared thermography method is subject to the impact of lubricating oil, can form mist of oil after lubricating oil is heated in gear case, and the lubricating oil simultaneously splashed can be splashed on temperature probe, interference measurement results; In addition, due to the special construction of gear, infrared temperature sensor can only be arranged on gear housing outside, need open detection window on casing, cannot measure the temperature of mesh tooth face.The oil temperature indirect method of measurement probably can only reflect the medial temperature of gear, does not possess real-time, more can not reflect the transient temperature of mesh tooth face simultaneously.The transient temperature of mesh tooth face is the actual reflection of gears meshing temperature, could accurately judge whether the working temperature of gear meets the requirements, and mesh tooth face temperature is too high, can cause On Gear Scoring burn etc. to the analysis of mesh tooth face temperature.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of Gear Root thermometry.

In order to solve the problems of the technologies described above, the technical solution used in the present invention is: a kind of Gear Root thermometry, comprises the following steps:

(1) pre-buried thermopair

Punch at the tooth root dual-side of tested gear, thermopair is inserted in the hole, with silicone rubber seal, extension line is transferred to data acquisition system (DAS) by collector ring;

Tooth root temperature adopts the method for pre-buried thermopair to measure, and after pre-buried K type thermopair, with silicone rubber seal, extension line is transferred to data acquisition system (DAS) by collector ring; Thermopair size is little, and dynamic responding speed is high, only after the punching of tooth root dual-side, need be inserted in the hole by thermopair, with silicone rubber seal;

(2) acquisition and processing of temperature signal

Because the thermopair being embedded in tooth root rotates with gear, gather the signal of thermopair, must be real-time transmitted in host computer by signal, the present invention adopts high speed collector ring to be real-time transmitted in host computer data acquisition system (DAS) by the electric signal of pre-buried for tooth root thermopair.System software carries out automatic calibration at zero point before detection, and eliminate zero temperature impact, in addition, software systems take the method for autocorrelation filter, carry out filtering to temperature signal, eliminate interference.

(3) flank of tooth transient temperature calculates

In the frictional heating that the flowing ignoring bearing and oil causes, the thermal source of system is all the friction hot merit between mesh tooth face; According to Hertz contact theory, the thermal power Q of contact region central spot can be represented:

Q＝μ _mP _max|V ₁-V ₂|

Assuming that it is impartial that heat of friction is distributed between driving wheel and follower, then the theory of and flank of tooth transmission theoretical according to H.Blok, the maximum instantaneous temperature rise that can obtain contact region is:

$T_f=1.65\frac{{\mathrm{\μ}}_m{P}_{\max }|V_1-V_2|\sqrt{b}}{\sqrt{c_1{\mathrm{\λ}}_1{\mathrm{\γ}}_1{V}_1}+\sqrt{c_2{\mathrm{\λ}}_2{\mathrm{\γ}}_2{V}_2}}$

Instant contact temperature T is body temperature T _minstantaneous temperature T _fsum, then:

T＝T _M+T _f

T _M＝T _o+0.1W _t

$P_{max}=\frac{3F}{2\mathrm{\π}ab}$

T _f: maximum instantaneous temperature rise, T: instant contact temperature, T _m: gear temperature, T _o: lubricating oil temperature, W _t: the circumferential load in the unit facewidth, u _m: the coefficient of sliding friction, P _max: the maximum unit stress of contact center, V ₁, V ₂: gear in the sliding speed at meshing point place, a, b: the major axis of meshing point place Contact Ellipse and minor axis radius, c ₁, c ₂: the specific heat of gear material, λ ₁, λ ₂: the coefficient of heat conductivity of gear material, γ ₁, γ ₂: the density of gear material, F: tooth face meshing point normal load;

According to above-mentioned various, and the lubricating oil temperature recorded and gear temperature, the transient temperature of the last position of engagement of the flank of tooth can be calculated, thus obtain the temperature field of the flank of tooth.

As preferably, described thermopair is K type thermopair.

The invention has the beneficial effects as follows:

The present invention is by detecting tooth root temperature, and the transient temperature of indirect calculation mesh tooth face is the very valuable reference that design of gears provides.In traditional gear temperature detects, owing to only considering the medial temperature of gear, and have ignored the transient temperature of mesh tooth face, and the transient temperature of mesh tooth face is only the direct factor causing gear to produce gummed burn; Especially to heavily loaded high gear, the transient temperature of flank engagement is particularly important, the invention solves the transient temperature difficult problem how obtaining the gears meshing flank of tooth.

Embodiment

(1) pre-buried thermopair

Punch at the tooth root dual-side of tested gear, K type thermopair is inserted in the hole, with silicone rubber seal, extension line is transferred to data acquisition system (DAS) by collector ring;

Tooth root temperature adopts the method for pre-buried thermopair to measure, and thermopair size is little, and dynamic responding speed is high, and simple to operate;

(2) flank of tooth transient temperature calculates

Gear, in engagement process, produces heat of friction due to the phase mutual friction between the flank of tooth.Heat of friction makes the surface temperature of contact Tooth rise.Due to the rotation of gear, be separated rapidly by the surface of contact of instantaneous heating, under fixed rotating speed and load-up condition, will reach thermal equilibrium state in instantaneous heating and temperature rise process, now the temperature of gear is body temperature.The body temperature of gear is substantially constant, but the surface of contact of the gear teeth instantaneously still can produce a large amount of heat at surface of contact in engagement, and this temperature is called instantaneous temperature.The instant contact temperature of gear teeth face is exactly the superposition of body temperature and instantaneous temperature.

High speed scroll also with two Gear Contact Surfaces slided, because of the heat produced that rubs, can cause wheel temperature to raise; And too high gear teeth temperature will cause the lubricating oil film between mesh tooth face to break, metal directly contacts and spot welding occurs, and under the effect of sliding speed, solder joint is torn and forms gummed destruction.

The principal element affecting gear instant contact temperature has following several:

1) impact of gear geometry parameter

The change of the gear teeth facewidth and modulus will cause the change of wheel teeth size, volume and load-bearing capacity thus causes the change of gear teeth body temperature.When the facewidth increases, the heat of friction current density of surface of contact is not easy the lubricating oil cooling diffusion by Gear Contact Surface and gear teeth end face; And facewidth increasing causes gear volume to increase, and also makes the heat transfer of heat of friction current density in denticle more difficult, therefore flank of tooth body temperature raises.Under identical load and speed conditions, the flank of tooth normal load of the gear that the gear that modulus is large is little compared with modulus is low; Flank of tooth relative sliding velocity is high; Convection transfer rate is large; And volume increases.The size of heat of friction current density and the height of gear temperature and face temperature will depend on the combined influence of above-mentioned factor.

2) impact of gear tooth friction heat flow density

The size of tooth bearing heat of friction current density depends on that partition factor between principal and subordinate wheel tooth of the contact of the field of conjugate action, friction factor, relative sliding velocity and heat of friction current density and friction energy are converted to the coefficient of heat energy.Wherein the size of face pressure and distribution will directly affect size and the distribution of surface of contact heat of friction current density, and produce conclusive impact to gear teeth body temperature and instant contact temperature.The friction factor of surface of contact and relative sliding velocity are also the principal elements affecting heat of friction current density.

3) impact of gear convection transfer rate

High Speed Gearing generally adopts flank of tooth oil jet lubrication.Under high rotational speeds, gear face adopts the method for single-phase liquid flow analysis convection transfer rate to need to revise, the laminar flow namely needing to determine to be produced at gear face by air and lubricating oil mixed flow, transition bed flowing and turbulent.And tooth bearing is only at instantaneous acquisition Oil injection cooling of engagement, have the feature of intermittence transient state forced convertion cooling, Water demand heat of friction current density estimates convection transfer rate by the process of centrifugal impelling cooling diffusion.The convection transfer rate of gear face and surface of contact changes along with the position of flank engagement, the speed of rotation and operating conditions.

In the frictional heating that the flowing ignoring bearing and oil causes, the thermal source of system is all the friction hot merit between mesh tooth face; According to Hertz contact theory, the thermal power Q of contact region central spot can be represented:

Q＝μ _mP _max|V ₁-V ₂|

Assuming that it is impartial that heat of friction is distributed between driving wheel and follower, then the theory of and flank of tooth transmission theoretical according to H.Blok, the maximum instantaneous temperature rise that can obtain contact region is:

$T_f=1.65\frac{{\mathrm{\μ}}_m{P}_{\max }|V_1-V_2|\sqrt{b}}{\sqrt{c_1{\mathrm{\λ}}_1{\mathrm{\γ}}_1{V}_1}+\sqrt{c_2{\mathrm{\λ}}_2{\mathrm{\γ}}_2{V}_2}}$

Instant contact temperature T is body temperature T _minstantaneous temperature T _fsum, then:

T＝T _M+T _f

T _M＝T _o+0.1W _t

$P_{max}=\frac{3F}{2\mathrm{\π}ab}$

T _f: maximum instantaneous temperature rise, T: instant contact temperature, T _m: gear temperature, T _o: lubricating oil temperature, W _t: the circumferential load in the unit facewidth, u _m: the coefficient of sliding friction, P _max: the maximum unit stress of contact center, V ₁, V ₂: gear in the sliding speed at meshing point place, a, b: the major axis of meshing point place Contact Ellipse and minor axis radius, c ₁, c ₂: the specific heat of gear material, λ ₁, λ ₂: the coefficient of heat conductivity of gear material, γ ₁, γ ₂: the density of gear material, F: tooth face meshing point normal load;

According to above-mentioned various, and the lubricating oil temperature recorded and gear temperature, the transient temperature of the last position of engagement of the flank of tooth can be calculated, thus obtain the temperature field of the flank of tooth.

The present embodiment is by detecting tooth root temperature, and the transient temperature of indirect calculation mesh tooth face is the very valuable reference that design of gears provides.

In traditional gear temperature detects, owing to only considering the medial temperature of gear, and have ignored the transient temperature of mesh tooth face, and the transient temperature of mesh tooth face is only the direct factor causing gear to produce gummed burn; Especially to heavily loaded high gear, the transient temperature of flank engagement is particularly important, the invention solves the transient temperature difficult problem how obtaining the gears meshing flank of tooth.

Above-described embodiment of the present invention, does not form limiting the scope of the present invention.Any amendment done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within claims of the present invention.

Claims (2)

1. a Gear Root thermometry, comprises the following steps:

(1) pre-buried thermopair

Punch at the tooth root dual-side of tested gear, thermopair is inserted in the hole, with silicone rubber seal, extension line is transferred to data acquisition system (DAS) by collector ring;

(2) flank of tooth transient temperature calculates

In the frictional heating that the flowing ignoring bearing and oil causes, the thermal source of system is all the friction hot merit between mesh tooth face; The thermal power Q of contact region central spot can be expressed from the next:

Q＝μ _mP _max|V ₁-V ₂|

Assuming that it is impartial that heat of friction is distributed between driving wheel and follower, the maximum instantaneous temperature rise that can obtain contact region is:

$T_f=1.65\frac{{\mathrm{\μ}}_m{P}_{\max }|V_1-V_2|\sqrt{b}}{\sqrt{c_1{\mathrm{\λ}}_1{\mathrm{\γ}}_1{V}_1}+\sqrt{c_2{\mathrm{\λ}}_2{\mathrm{\γ}}_2{V}_2}}$

Instant contact temperature T is body temperature T _mwith instantaneous temperature T _fsum, then:

T＝T _M+T _f

T _M＝T _o+0.1W _t

$P_{max}=\frac{3F}{2\mathrm{\π}ab}$

T _f: maximum instantaneous temperature rise, T: instant contact temperature, T _m: gear temperature, T _o: lubricating oil temperature, W _t: the circumferential load in the unit facewidth, u _m: the coefficient of sliding friction, P _max: the maximum unit stress of contact center, V ₁, V ₂: gear in the sliding speed at meshing point place, a, b: the major axis of meshing point place Contact Ellipse and minor axis radius, c ₁, c ₂: the specific heat of gear material, λ ₁, λ ₂: the coefficient of heat conductivity of gear material, γ ₁, γ ₂: the density of gear material, F: tooth face meshing point normal load;

According to above-mentioned various, and the lubricating oil temperature recorded and gear temperature, the transient temperature of the last position of engagement of the flank of tooth can be calculated, thus obtain the temperature field of the flank of tooth.

2. Gear Root thermometry according to claim 1, is characterized in that, described thermopair is K type thermopair.