JPH07333200A - Electrolytic corrosion evaluation test device for bearing - Google Patents

Abstract

PURPOSE:To evaluate the anti-corrosion property of a rolling bearing and lubricating agent, etc., while measuring and recording the electric characteristics by providing a rolling bearing, a housing, a drive motor, a support bearing, a base plate, an insulation plated, and an applying power supply. CONSTITUTION:A lubricating film is formed on each of lubricating surfaces among the outer ring 1a, the roller 1b, and the inner ring 1c of a cylindrical roller bearing 1 and the outer ring 2a, the roller 2b, the inner ring 2c of a ball bearing 2. The destructive voltage of the lubricating film or the anti-corrosion property of the bearing is measured and evaluated by applying a voltage between an electric contact point 7 provided on each housing 3 and the electric contact point 9 of a slip ring 8 installed at the end surface of a rotary shaft 4. In addition, when a voltage is applied between the bearing 1 and the bearing 2, the destructive voltage of the lubricating film between both bearings or concerned anti-corrosion property can be evaluated. In addition, by installing a heating heater and a temperature sensor in the vicinity of a bearing to be tested such as bearing 1 or bearing 2, the destructive voltage of the lubricating film under a high temperature condition or damaged status of the bearing due to electrical corrosion, temperature rise, etc., can be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test apparatus for evaluating electrolytic corrosion generated on lubricated surfaces of rolling bearings such as electric motors and axles, journal bearings and gears, and electrolytic corrosion resistance due to the lubricant.

[0002]

2. Description of the Related Art Lubricating oil load capacity test method (JIS K 2519) is available for evaluating the friction and wear characteristics of lubricants. This test method is the Soda four-ball friction test method in which a rotating ball is pressed against the center of three fixed steel balls, and the Chimken test method using the outer ring and block of a tapered roller bearing. Besides this, V
There are Falex friction tests using blocks / pins, friction testers using balls or rings, and reciprocating friction testers using balls or blocks. These test methods evaluate the maximum load or maximum pressure supported by the lubricant without causing seizure or other damage to the sliding friction contact surface under constant friction conditions, or the maximum load and friction / wear phenomenon that does not cause scoring. Is what
It is not a test device for evaluating the electrolytic corrosion of bearings and the electrolytic corrosion resistance of lubricants. The state of seizure or damage on the frictional contact surface and the friction / wear characteristics depend on the frictional / wear characteristics, load bearing performance, etc. of the lubricating film (oil film or film) formed between the friction surfaces. As a method of measuring the formation state of the lubricating film, there are a method of measuring the distance between the friction surfaces based on the transmittance of light or X-rays and an electric method of the capacitance method or the electric resistance method. In the capacitance method, an AC voltage is applied between the sliding friction surfaces, and the thickness of the lubricating film is measured from the capacitance. In the electric resistance method, a DC voltage is applied between the sliding friction surfaces, and the thickness of the lubricating film and the true contact area are measured from the electric resistance between the two surfaces. Under lubrication conditions in which the lubricating film breaks and the sliding surfaces come into direct contact with each other, the changes in both capacitance and electrical resistance are large, making measurement very difficult. A technique of applying a minute DC voltage to judge whether the insulating state is due to the lubricating film or the energized state by breaking and measuring the lubricating film from the voltage-current characteristics [Lubrication, Vol. 24, No. 6]
(1979) p331-336, "Lubrication" Vol. 25, No. 6 (1980) p395-399, "Lubrication" Vol. 30, No. 12 (1985) p883-886]. All of these technologies apply a small voltage of AC or DC between the two sliding friction surfaces to determine the thickness and formation state of the lubricating film from the electrostatic capacitance or electric resistance between the two surfaces or the change in the energized state. This is a measurement, not a test evaluation of abnormal wear or damage caused by electric current flowing through the lubricated surfaces of rotating bearings and gears.

[0003]

In recent years, a rolling bearing, a gear, etc. of a motor having a large output, which uses a lubricant such as lubricating grease or lubricating oil, has a voltage between the outside or a surface of the motor itself, which causes rolling or slippage. As a result, a phenomenon frequently called electro-corrosion that causes electric discharge on the lubrication surface due to a current flowing through or destroying a lubricant film formed by the lubricant to cause crater-like damage, abnormal wear, and blackening of the lubricant.
The electrolytic corrosion is affected by the magnitude of the current, frequency, voltage, etc. flowing through the lubricating film, and the greater the electrical characteristics, the greater the damage, and in some cases, burnout.
It is known that the damage condition of electrolytic corrosion varies greatly depending on the composition of the lubricant and the type of additive. Although there is a strong demand for measures to prevent or suppress electrolytic corrosion of rolling bearings and gears, the current situation is that there is no test device that can accurately evaluate these effects.

An object of the present invention is to insulate the surroundings with an insulator so that a voltage can be applied only between the inner and outer rings of a rolling bearing in order to evaluate the occurrence of electrolytic corrosion in rolling bearings and the influence of lubricants, and An object of the present invention is to provide a test device for evaluating the electrolytic corrosion resistance performance of rolling bearings and lubricants while measuring and recording the characteristics.

[0005]

In order to solve the above problems, the present invention provides a housing for fixing a rolling bearing, a drive motor for rotating the bearing, and a support for applying a load to a rolling bearing for test. This is an electrolytic corrosion evaluation test device composed of a test part main body in which an insulator is interposed between a bearing and a base plate fixing these, and an applied power source for applying a voltage to the rolling bearing. The test section body has a structure in which the housing and the end surface of the rotating shaft are in electrical contact with each other via a slip ring attached. The electric power supply circuit applied to the rolling bearing is designed to measure and record these electrical characteristics.

For the voltage and current measurement, the breakdown voltage (withstand voltage) of the lubricating film, the change in voltage, the current value during discharge, the frequency, etc. can be continuously measured by a digital multimeter. These measurement data can be processed and recorded by a computer to grasp the wear and damage conditions of the rolling bearing lubricated surface due to electrolytic corrosion.

When the voltage applied to the lubrication surface of the rolling bearing is direct current, the state of wear and damage differs depending on the polarity, so a polarity can be reversed by providing a changeover switch in the circuit. In addition, a vibrometer, AE
By installing an (acoustic emission) device, it becomes possible to predict the usage limit of the rolling bearing by analyzing the wear and damage of the lubricated surface of the rolling bearing due to electrolytic corrosion. When a heater and a temperature measuring sensor are attached to the rolling bearing, it becomes possible to measure the breakdown voltage of the lubricating film under high temperature conditions, the state of damage to the bearing due to electrolytic corrosion, the temperature rise, and the like.

[0008]

Since the insulator is interposed between the housing, the load support bearing and the drive motor and the base plate fixing them, the voltage can be applied only to the rotary shaft side and the housing side or the housing sides. It is possible to understand the allowable value of electric characteristics and countermeasures for suppression, as well as the state of wear and damage caused by electrolytic corrosion on the lubricated surface of the rolling bearing. In addition, the AC / DC voltage converter, variable frequency converter, capacitance measuring instrument, etc. can be applied to the lubrication surface of the rolling bearing to apply the electrical characteristics corresponding to the actual machine conditions. Can be implemented

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows an apparatus for testing electrolytic corrosion resistance of a bearing in which a cylindrical roller bearing and a deep groove ball bearing are incorporated. The cylindrical roller bearing 1 and the deep groove ball bearing 2 are fixed to the housing 3. The cylindrical roller bearing 1 and the deep groove ball bearing 2 are filled with lubricating grease, and the inner ring 1c of the cylindrical roller bearing 1 and the inner ring 2c of the deep groove ball bearing 2 are fitted to the rotary shaft 4, and the rotary shaft 4 is a cup. The rotating shaft 4 is rotated by the drive motor 6 connected to the ring 5, and the roller 1b of the cylindrical roller bearing 1 and the roller 2b of the deep groove ball bearing 2 are rotated. The outer ring 1a and the inner ring 1b of the cylindrical roller bearing 1
c, the outer ring 2a and the inner ring 2c of the deep groove ball bearing 2
A lubricating film is formed on the lubricated surfaces of and. The breakdown voltage of the lubricating film or the electrolytic corrosion resistance of the bearing is measured and evaluated by applying a voltage between the electric contact 7 mounted on the housing 3 and the electric contact 9 of the slip ring 8 mounted on the end face of the rotating shaft 4. To do. When a voltage is applied between the cylindrical roller bearing 1 and the deep groove ball bearing 2, the breakdown voltage of the lubricating film between both bearings or the electrolytic corrosion resistance can be evaluated. The current flowing through the lubricating film or the current at the time of discharge flows like the current circuit 13 shown by the broken line.

The housing 3, the load support bearing 10, the coupling 5 and the drive motor 6 are fixed to the base plate 14 via an insulator 12 for electrical insulation. The load applied to the cylindrical roller bearing 1 and the deep groove ball bearing 2 is performed via a load support bearing 10 by a load device 11 including hydraulic pressure or a spring. Also, by installing a heater and temperature sensor in the vicinity of the test bearings such as cylindrical roller bearings and deep groove ball bearings, the breakdown voltage of the lubricating film under high temperature conditions, the damage state of the bearings due to electrolytic corrosion, the temperature rise, etc. can be measured. You can do it.

FIG. 2 is a configuration diagram of an AC or DC applied power supply circuit applied to the cylindrical roller bearing 1 or the deep groove ball bearing 2 and measurement and recording.

AC input voltage 100V is variable AC / DC voltage converter 15 (AC voltage 15a, DC voltage 15b)
From the variable resistor 21, the current measuring device 16a to the electric contact 7 or the electric contact 9 and the variable AC / DC voltage converter 15 through the frequency converter 20 and the electric contact 7 or the electric contact 9 An alternating current or direct current voltage and a combined voltage of alternating current and direct current are applied to the electrical contact 7 of the cylindrical roller bearing 1 or the deep groove ball bearing 2 and the electrical contact 9 of the rotary shaft 4. The capacitance measuring device 19 measures the capacitance of the lubricating film formed on the cylindrical roller bearing 1 or the deep groove ball bearing 2. Further, the breakdown voltage of the lubricating film is measured by the digital multimeter voltmeter 16c. The breakdown voltage of the lubricating film and the current or discharge current and frequency flowing through the lubricating film are monitored by the measurement monitor 18 and recorded by the computer 17. The variable resistor 21 is used when controlling the maximum value of the current flowing between the bearing lubrication surfaces and adjusting the damage of the bearing due to electrolytic corrosion.

(Embodiment 2) FIG. 3 shows a bearing sample in the case where a thrust type roller bearing is used by improving the friction test portion of the Soda four-ball friction test device used for evaluating the friction and wear characteristics of the lubricant. 3 is a view showing an assembled cross section and a rotating part of a container part. The rotary wheel 22a of the thrust roller bearing 22 has a rotary shaft 23.
Fixed to. The roller 22b and the fixed ring 22c of the thrust roller bearing 22 are attached to a sample container 25 containing an insulating material 24 therein. The sample container 25 is pressed against the rotary shaft 23 by hydraulic pressure or a spring to apply a load to the thrust roller bearing 22. The thrust roller bearing 22 is filled with lubricating grease or lubricating oil. The slip ring 2 is attached to the rotary shaft 23.
The electrical contacts 27 of 6 are attached, and the rotating shaft 23 is rotated by the belt 28. A lubricating film is formed on the lubricated surface of the thrust roller bearing 22.

The voltage applied to the thrust roller bearing 22 is
The breakdown voltage of the lubricating film connected to the electrical contact 27 of the slip ring 26 fixed to the rotary shaft 23 and the electrical contact 24 attached to the sample container 25 shown in FIG. You can evaluate the condition.

By installing the heater 29 and a temperature sensor in the vicinity of the test bearing in the bearing sample container, it is possible to measure the breakdown voltage of the lubricating film under high temperature conditions, the damage state of the bearing due to electrolytic corrosion, the temperature rise, etc. .

In Examples 1 and 2, radial and thrust type rolling bearings were illustrated, but in the present invention, a voltage is applied between rolling and sliding friction surfaces or lubricating surfaces other than rolling bearings to form between two surfaces. Insulation materials and lubrication to prevent galvanic corrosion of rolling bearings, such as breakdown voltage of lubricating film and occurrence of electrolytic corrosion (generation of electric discharge marks and wear on friction surface or lubricating surface due to current flowing through lubricating film) It is possible to evaluate agents and the like.

(Embodiment 3) The results of measuring the damage state of the lubrication surface of the rolling bearing and the breakdown voltage of the lubricating film due to electrolytic corrosion by the electrolytic corrosion test apparatus for the bearing shown in Example 1 under the following conditions are shown in Table 1.
Shown in.

[0019]

[Table 1]

Test conditions (1) Test bearing: NU314 type cylindrical roller bearing, 6310 type deep groove ball bearing (2) Rotation speed: 5000 rpm (3) Load load: 250 kgf / bearing (4) Bearing outer ring temperature: 100 ° C (5 ) Frequency: 100 Hz (6) Lubrication grease: Lithium soap-mineral oil Under these test conditions, the application of electrolytic corrosion resistance test was carried out at an AC voltage of 4 V for 50 hours.

[0021]

According to the present invention, AC or DC voltage of various waveforms or a voltage is simultaneously applied to a completely insulated rolling or sliding friction surface or lubricating surface, and the surface is worn or damaged by electrolytic corrosion. The situation can be evaluated relatively quickly, and the selection and evaluation of bearings coated with an insulating material to prevent or suppress electrolytic corrosion and rolling bearings made of ceramics can be performed relatively quickly.
It can also be applied to prevent or suppress electrolytic corrosion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a device for testing electrolytic corrosion of a radial type rolling bearing and a breakdown voltage of a lubricating film and a test bearing and a load support bearing portion.

FIG. 2 is a block diagram of a power supply circuit applied to a rolling bearing.

FIG. 3 is a cross-sectional view of an apparatus for testing electrolytic corrosion of a thrust type rolling bearing and breakdown voltage of a lubricating film.

[Explanation of symbols]

1 ... Cylindrical roller bearing, 1a, 2a ... Outer ring, 1b, 2b ... Roller, 1c, 2c ... Inner ring, 2 ... Ball bearing, 3 ... Housing,
4 ... Rotary shaft, 5 ... Coupling, 6 ... Drive motor, 7,
9 ... Electric contact, 8 ... Slip ring, 10 ... Load support bearing, 11 ... Load device, 12 ... Insulator, 13 ... Current circuit, 14 ... Base plate.

Claims (3)

[Claims] 1. A friction surface or a lubrication surface in which an electrically insulated rolling or sliding lubricant intervenes, and an AC or DC voltage having various waveforms between the friction surface or the lubrication surface by a frequency converter, and A bearing electrolytic corrosion evaluation test apparatus, which measures and evaluates a breakdown voltage of a lubricating film and a discharge current or a surface damage or wear state caused by a discharge current while simultaneously applying the voltage. 2. An apparatus for evaluating electrolytic corrosion of a bearing according to claim 1, wherein the electrically insulated rolling or sliding frictional surface or lubricating surface is a rolling bearing. 3. A variable AC / DC voltage converter, a variable frequency converter, a capacitance measuring device, a voltmeter according to claim 1, wherein the power source applied to the electrically insulated friction surface or lubrication surface is Electrolytic corrosion evaluation test equipment for bearings consisting of an electric current measuring instrument, measurement monitor and recording device.