JP2010014474A - Detection method for detecting state of occurrence of contact fatigue damage on fixed type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To use the comparing data of the signals, which are respectively outputted from a preliminarily damaged component and a damage-free component, as an index showing the occurrence of contact fatigue damage because a certain time is required in order to detect the change point produced with respect to a component at the moment when the contact fatigue damage occurs in the component having a contact region related to the power transmission or the like of an automobile, that is, a signal showing a change. <P>SOLUTION: Hydrogen is charged to a partly component 1 (inner ring, outer ring, ball or the like) constituting the fixed type uniform velocity universal joint to perform a rolling contact fatigue test under a condition similar to the use condition of an actual component and the signal issued from the component 1 is succeedingly detected. By this method, the change point produced with respect to the component 1 at the moment when the contact fatigue damage occurs, that is, the signal showing the change can be efficiently detected with high precision in a short time as compared with the case where hydrogen is not charged to the component. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a detection method for detecting a state in which contact fatigue damage occurs in a fixed type constant velocity universal joint over time, and more particularly, to a power transmission and the like in a fixed type constant velocity universal joint. The present invention relates to a detection method for detecting a signal representing a change in a physical quantity that occurs with the occurrence of contact fatigue damage in a part having a contact portion with high accuracy.

  When a part having a contact portion related to power transmission of an automobile, for example, a part such as a fixed type constant velocity universal joint is continuously used, it is repeatedly contacted by traveling or turning of the automobile. For this reason, contact fatigue damage may occur in some of the constituent parts, which may cause malfunction. In recent years, in particular, there has been an increasing demand for lower fuel consumption in automobiles. To meet this demand, fixed type constant velocity universal joints have been reduced in size and weight. Because the torque transmitted by the fixed type constant velocity universal joint is relatively increased due to the reduction in size and weight, the load applied to the fixed type constant velocity universal joint increases, and the fixed type constant velocity universal joint has more severe conditions. It has come to be used in. As a result, the frequency of contact fatigue damage is increasing. Therefore, it is important to improve resistance in order to suppress contact fatigue damage.

  In order to improve the resistance for suppressing contact fatigue damage, for example, a design change or a material change is performed. In order to verify the effectiveness of the results of design changes and material changes in detail, the prototype of a fixed type constant velocity universal joint that has undergone design changes and material changes is continuously used under actual usage conditions. However, it is necessary to detect with high accuracy a signal representing a change that occurs in a part at the moment when the contact fatigue damage occurs, that is, a change in physical quantity. The signal data representing the change at the moment when damage occurs, thus detected, contains a lot of useful information related to, for example, how damage occurs and the life of parts. For this reason, the data of this signal can be used as an index indicating that the contact fatigue damage has occurred in the subsequent contact fatigue damage test.

Conventionally, various methods for diagnosing contact fatigue damage have been proposed. For example, in Japanese Patent Application Laid-Open No. 2007-285874 (Patent Document 1), a sound or vibration when the outer ring raceway surface of a double-row tapered roller bearing has been subjected to defects under actual use conditions is disclosed. A method of detecting the presence or absence of a defect by detecting a signal and comparing it with a signal when a double-row tapered roller bearing having no defect is used under actual use conditions is disclosed.
JP 2007-285874 A

  The conventional diagnostic method described above does not detect a signal representing a change at the moment when damage occurs. Therefore, usefulness such as the amount of information included in the detected signal is inferior to a signal representing a change at the moment when damage occurs. In other words, conventional detection methods that compare vibration signals between parts that have been previously defective and parts that do not have defects are insufficient, and it is possible to detect signals that represent changes at the moment when the parts are damaged. It is considered important. However, when used under actual usage conditions, it takes a long time to cause contact fatigue damage. For this reason, it takes a long time to detect a signal representing a change at the moment when contact fatigue damage occurs.

  The present invention has been made in view of the above-described problems. Its purpose is to use contact-type constant velocity universal joints that have contact parts related to power transmission, etc. under conditions close to actual usage conditions, and to cause contact fatigue damage in a short time. It is an object of the present invention to provide a detection method for detecting a signal representing a change, which occurs at the moment when the error occurs, with high accuracy.

  The detection method in the present invention is a detection method for detecting a change over time that occurs when contact fatigue damage occurs in a bench test of a fixed type constant velocity universal joint. The detection method includes a step of charging a fixed type constant velocity universal joint with hydrogen and a step of detecting a signal output in a process in which the fixed type constant velocity universal joint charged with hydrogen generates contact fatigue damage. Prepare.

  Specifically, a fixed type constant velocity universal joint, which is a part having a contact part related to power transmission of an automobile, is prepared as a test part. Of the fixed type constant velocity universal joint as the test part, hydrogen is contained (charged with hydrogen) in a part where contact fatigue damage is to occur. In this way, since the material of the component deteriorates due to the influence of hydrogen, contact fatigue damage can be generated in a short time in the bench test. In addition, the fixed type constant velocity universal joint is continuously used under actual use conditions. During continuous use, it detects and records changes over time in signals such as sound and temperature output from the fixed type constant velocity universal joint. Then, since a signal indicating a change in the component, that is, a change in physical quantity, is output at the moment when the fixed type constant velocity universal joint generates contact fatigue damage, the signal indicating this change can be detected with high accuracy.

  In the detection method of the present invention, electrolysis can be performed in a method of charging hydrogen to a fixed type constant velocity universal joint. For example, there is a method of performing electrolysis in a solution obtained by adding thiourea as a catalyst poison to a dilute sulfuric acid aqueous solution. Alternatively, for example, electrolysis may be performed in a solution obtained by adding ammonium thiocyanate as a catalyst poison to a sodium chloride aqueous solution. Electrolysis may be performed in a solution obtained by adding sodium sulfide nonahydrate as a catalyst poison to an aqueous sodium hydroxide solution. By performing electrolysis, hydrogen can be charged to the fixed type constant velocity universal joint.

  In the detection method of the present invention, in the step of charging hydrogen to the fixed type constant velocity universal joint, hydrogen is charged to the fixed type constant velocity universal joint by immersing in, for example, an aqueous solution of ammonium thiocyanate instead of electrolysis. You may use the method of. By using this method, hydrogen can be charged to the fixed type constant velocity universal joint more easily and cheaply than the method of performing electrolysis.

  According to the present invention, it is possible to cause contact fatigue damage to some parts of a fixed type constant velocity universal joint in a short time, and to increase a signal indicating a change generated at the moment when the contact fatigue damage occurs. It can be detected with accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and the description thereof will not be repeated unless particularly necessary.

  FIG. 1 is a flowchart showing the steps of the detection method according to the embodiment of the present invention. The present invention makes contact with a part of a fixed type constant velocity universal joint by receiving repeated contact when the fixed type constant velocity universal joint, which is a part having a contact part related to power transmission of an automobile, is continuously used. The present invention provides a method for detecting a signal representing a change (change in the occurrence state of contact fatigue damage with time) generated at the moment when fatigue damage occurs with high accuracy. The outline of the process will be described below. First, as shown in FIG. 1, a step of charging hydrogen (S10) is performed. Specifically, in a fixed type constant velocity universal joint prepared as a test part, for example, an inner ring, an outer ring, or a ball that is about to cause contact fatigue damage in a short time is subjected to, for example, electrolysis. This is a step of precharging hydrogen.

  And the process (S20) to continue using is implemented. Specifically, this is a step of continuously applying a load to the test component charged with hydrogen under substantially the same conditions as those used for the above-described fixed type constant velocity universal joint. By performing the signal detecting step (S21) while performing this continuous use, during the continuous use, the inner ring that is a part of the fixed type constant velocity universal joint, in particular, charged with hydrogen, A step of detecting and recording a change with time of a signal such as sound or temperature output from the outer ring or the ball is performed. Then, because the material of the inner ring, outer ring, or ball has deteriorated due to the effect of hydrogen charged to the inner ring, outer ring, or ball, contact fatigue damage can be caused in the test part in a shorter time than usual. . In addition, by charging hydrogen, contact fatigue damage can be caused in a shorter time than usual, but the manner of damage is not different from the normal case. Therefore, by charging hydrogen, it is possible to accurately reproduce a signal representing a change that is output at the moment when the fixed type constant velocity universal joint generates contact fatigue damage in a shorter time than usual.

  In addition, a process (S20) and a process (S21) may be started simultaneously, and a process (S21) may be started after a fixed time passes after starting a process (S20). Alternatively, depending on the detection method, the step (S20) and the step (S21) may be repeated a plurality of times. Further, by performing the step (S21) while performing the step (S20), it is possible to detect with high accuracy a signal representing a change that is output at the moment when a component charged with hydrogen causes contact fatigue damage. Hereinafter, each process described above will be described in more detail.

  FIG. 2 is a schematic view showing a state where the fixed type constant velocity universal joint is installed under the same conditions as those used. As shown in FIG. 2, a fixed type constant velocity universal joint 100 that is a part having a contact portion related to power transmission of an automobile is installed on the tire side of the automobile (the left side in the figure, that is, the outside of the vehicle body). Via a hub, suspension and wheels (not shown). The sliding type constant velocity universal joint 200 is connected to an engine or a differential gear (not shown) via a shaft 37. The fixed type constant velocity universal joint 100 is connected to the sliding type constant velocity universal joint 200 via a shaft 35.

  FIG. 3 is a schematic cross-sectional view showing a configuration of a fixed type constant velocity universal joint. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. Here, line segment III-III in FIG. 4 indicates that the schematic cross-sectional view along the line segment is FIG. 3. FIG. 5 is a schematic cross-sectional view showing a state where the fixed type constant velocity universal joint of FIG. 3 forms an angle. As shown in FIG. 3, the fixed type constant velocity universal joint 100 includes a torque transmission ball 33 disposed between an inner ring 31 fixed to a shaft 35 and an outer ring 32 integrally formed with the shaft 36. It rolls on the surface of the inner ring groove 31 </ b> A formed on the outer peripheral surface of the inner ring 31 and the outer ring groove 32 </ b> A formed on the inner peripheral surface of the outer ring 32. As shown in FIG. 4 which is a cross-sectional view of FIG. 3, the ball 33 is held by the cage 34 so as not to drop off. When this fixed type constant velocity universal joint 100, for example, a wheel (not shown) connected to the shaft 36 integral with the outer ring 32 rides on a convex raised portion on the road when the vehicle is traveling, as shown in FIG. The ball 33 rolls on the rolling surface of the ball 33, which is the surface of the inner ring groove 31 </ b> A and the outer ring groove 32 </ b> A, so that the shaft 36 forms an angle θ with respect to the shaft 35. Thus, the angle θ changes each time the wheel travels on various uneven surfaces on the road, and the ball 33 reciprocates while rolling on the rolling surface that is the surface of the inner ring groove 31A and the outer ring groove 32A. As a result, the inner ring 31, the outer ring 32, and the surface of the ball 33 are eventually damaged by contact fatigue. This is the contact fatigue damage described above. Since the present invention relates to a method for capturing, for example, a signal change at the moment when the contact fatigue damage occurs, it is preferable to detect the moment when the contact fatigue damage occurs with respect to the inner ring 31, the outer ring 32, or the ball 33. Therefore, in the step (S10), in order to cause contact fatigue damage to the inner ring 31, the outer ring 32, or the ball 33 in a short time, hydrogen is charged in advance, for example, by electrolysis.

  First, a step of charging hydrogen (S10) is performed. This is a step of charging the inner ring 31, the outer ring 32, or the ball 33 with hydrogen, for example, by performing electrolysis. FIG. 6 is a schematic diagram showing a state in which hydrogen is charged to a component by electrolysis. As shown in FIG. 6, a vessel such as a beaker for scientific experiments is filled with a solution, and an anode and a cathode are prepared inside the solution. For example, an inner ring 31, an outer ring 32, or a ball 33 is connected as a part 1 to be charged with, for example, a platinum electrode at the anode and charged with hydrogen at the cathode. As described above, if the wheel travels on various uneven surfaces on the road, the ball 33 reciprocates while rolling on the rolling surface, so that contact fatigue damage is caused on the surfaces of the inner ring 31, the outer ring 32, and the ball 33. Therefore, it is preferable to charge the inner ring 31, the outer ring 32, or the ball 33 with hydrogen. Here, all of the inner ring 31, the outer ring 32, and the ball 33 may be charged with hydrogen, or only some of these parts may be charged with hydrogen.

  As the solution 5 filling the container of FIG. 6, for example, a solution obtained by adding thiourea to dilute sulfuric acid aqueous solution is used. In this case, the concentration of dilute sulfuric acid is preferably adjusted to a concentration of about 0.05 mol / L, more specifically 0.04 mol / L or more and 0.06 mol / L or less. When an acidic aqueous solution is used in this way, the efficiency of charging the component 1 with hydrogen is improved. Thiourea is a catalyst poison and is used to increase the efficiency of hydrogen charging. In order to maximize the efficiency of hydrogen charging, the concentration of thiourea added is preferably 1.2 g / L or more and 1.4 g / L or less. The catalyst poison is a substance having a catalytic action that lowers the activation energy in the process in which atomic hydrogen is adsorbed on the surface of the steel forming the part 1 and enters the steel during hydrogen charging. It is. The reason why the lower limit of the thiourea concentration range is set to 1.2 g / L is that the efficiency is lowered if the concentration is lower than that. The reason why the upper limit of the thiourea concentration range is set to 1.4 g / L is that the efficiency does not increase even if the concentration is increased beyond that.

  By the way, when hydrogen is charged in an acidic aqueous solution as described above, the surface of the part 1 is covered with a thin corrosion product. Therefore, after hydrogen is charged, the surface of the part 1 is re-wrapped to improve surface roughness. It is preferable to do.

  Instead of using the acidic aqueous solution described above for performing electrolysis, for example, a sodium chloride aqueous solution may be used. In this case, it is preferable to adjust the concentration of sodium chloride to a concentration of about 3% by mass, more specifically 2% by mass to 4% by mass. When using a sodium chloride aqueous solution, for example, ammonium thiocyanate can be used as a catalyst poison used to increase the efficiency of hydrogen charging. In order to maximize the efficiency of hydrogen charging, the concentration at which ammonium thiocyanate is added is preferably 2.5 g / L or more and 3 g / L or less. The reason why the lower limit of the ammonium thiocyanate concentration range is set to 2.5 g / L is that if the concentration is lower than that, the efficiency decreases. Moreover, the reason why the upper limit of the ammonium thiocyanate concentration range is 3 g / L is that the efficiency does not increase even if the concentration is increased. Further, the concentration range of ammonium thiocyanate is more preferably 2.8 g / L or more and 3.0 g / L or less. In this way, it is possible to obtain an effect that more stable hydrogen charging can be performed.

  When hydrogen is charged in an aqueous sodium chloride solution, the surface of the part 1 may be covered with a thin corrosion product. Therefore, after hydrogen is charged, the surface of the part 1 is re-wrapped to improve surface roughness. Is more preferable.

  Further, an alkaline aqueous solution, for example, a sodium hydroxide aqueous solution can be used for the electrolysis. In this case, it is preferable to adjust the concentration of sodium hydroxide to about 1 mol / L, more specifically to a concentration of 0.8 mol / L to 1.2 mol / L. In the case of using an aqueous sodium hydroxide solution, for example, sodium sulfide nonahydrate can be used as the catalyst poison used to increase the efficiency of hydrogen charging. In order to maximize the efficiency of hydrogen charging, the concentration of sodium sulfide nonahydrate added is preferably 0.8 g / L or more and 1 g / L or less. The reason why the lower limit of the concentration range of sodium sulfide nonahydrate is set to 0.8 g / L is that if the concentration is lower than that, the efficiency decreases. The reason why the upper limit of the concentration range of sodium sulfide nonahydrate is set to 1 g / L is that the efficiency is not improved even if the concentration is increased. When electrolysis is performed using an alkaline aqueous sodium hydroxide solution, no corrosion product is generated on the surface of the part 1 after charging with hydrogen.

  Furthermore, as a method of charging the parts 1 such as the inner ring 31, the outer ring 32, and the balls 33 with hydrogen, there is a method that does not use electrolysis. FIG. 7 is a schematic view showing a state where parts are charged with hydrogen by being immersed in an aqueous solution. As shown in FIG. 7, there is also a method in which the component 1 is simply immersed in an aqueous solution 6, for example. Specifically, an aqueous solution of ammonium thiocyanate is used as the aqueous solution 6. The component 1 is charged with hydrogen by immersing the component 1 in this ammonium thiocyanate aqueous solution. At that time, the concentration of ammonium thiocyanate in the ammonium thiocyanate aqueous solution is preferably 5% by mass or more and 20% by mass or less. In this way, hydrogen can be charged by simply immersing in an aqueous solution without using electrolysis. By using this method, the component 1 can be charged with hydrogen more easily and cheaply than the method of performing electrolysis. The reason why the lower limit of the ammonium thiocyanate concentration is set to 5% by mass is that if it is less than that, the amount of hydrogen necessary for causing contact fatigue damage in a short time is not charged. The upper limit of the ammonium thiocyanate concentration is 20% by mass because the concentration of charged hydrogen is saturated at 20% by mass.

  By charging the component 1 with hydrogen, the material deteriorates due to the influence of the hydrogen contained in the component 1, so that contact fatigue damage is caused to the component 1 in a shorter time than the normal case where hydrogen is not charged. Can wake up. Since the material of the component 1 is deteriorated due to the charged hydrogen, contact fatigue damage can be caused in a shorter time than usual. In addition, by charging hydrogen, contact fatigue damage can be caused in a shorter time than usual, but the manner of damage is not different from the normal case. Therefore, by charging hydrogen, it is possible to accurately reproduce a signal representing a change that occurs at the moment when contact fatigue damage occurs in a shorter time than usual.

  As described above, when the step of charging hydrogen (S10) is completed, the step of continuous use (S20) is performed. FIG. 8 is a schematic view showing a state in which the prepared fixed type constant velocity universal joint is actually assembled. As shown in FIG. 8, each part is prepared, and a fixed amount of grease is charged into the fixed type constant velocity universal joint 100 and the sliding type constant velocity universal joint 200 in which the part 1 is charged with hydrogen, and a boot 110 is attached. Both are connected by a shaft 35. The boot 110 is a cover that protects the fixed type constant velocity universal joint 100 and the sliding type constant velocity universal joint 200, and not only the scattering of grease but also the entry of dust, dust, or the like that hinders safe operation. It was installed to suppress it. The end of the shaft 36 integral with the outer ring 32 of the fixed type constant velocity universal joint 100 is connected to a suspension, hub, and wheels (not shown). Further, it is connected to an engine or a differential gear (not shown) via a shaft 37 integral with the outer ring of the sliding type constant velocity universal joint 200.

  Then, as shown in FIG. 6 described above, by giving a constant torque to the shaft 36, the shaft 35, and the shaft 37 in a state where a constant operating angle θ is taken between the shaft 36 and the shaft 35, It is actually mounted as a car part and operated under the same conditions as when the car is running. At this time, since θ takes a substantially constant value, the ball 33 does not reciprocate while rolling on the rolling surface which is the surface of the inner ring groove 31A and the outer ring groove 32A, but the ball 33 is the same on the rolling surface. Contact fatigue damage occurs by continuing contact with this point. The operating angle θ is preferably 1 to 15 degrees, and more preferably 5 to 10 degrees. The angle within the above-described range is a range of values of the operating angle θ that can be taken during normal driving of the automobile. By continuing the above state, the component 1 is continuously brought into contact with other components.

  While performing the continuous use step (S20) as described above, the signal detection step (S21) is performed. Specifically, the process of detecting and recording the change over time of the signal output from the hydrogen-charged component 1 of the fixed type constant velocity universal joint 100 during continuous use and contact. It is.

  For example, temperature, sound, and transmission error can be used as a signal for detecting a change with time. Here, the temperature signal is a signal obtained by monitoring the surface temperature of the outer ring 32 that can be measured. The sound signal is a sound wave signal emitted by the component 1 that is continuously touching while rotating. Furthermore, in a normal state, the constant velocity of rotation between the sliding-type constant velocity universal joint 200 on the input side and the fixed-type constant velocity universal joint 100 on the output side is maintained. When contact fatigue damage occurs in the component 1, a deviation from constant velocity occurs. The transmission error is a parameter indicating the deviation.

  FIG. 9 is a schematic diagram showing a situation in which a temperature signal of a part charged with hydrogen is detected. In order to continuously detect the temperature signal of the surface of the outer ring 32 of the fixed type constant velocity universal joint 100, for example, a radiation thermometer 7 is installed in the vicinity of the outer ring 32 as shown in FIG. Then, while continuously contacting the component 1 in the step of continuous use (S20), the radiation thermometer 7 continuously detects and records the temperature signal on the surface of the outer ring 32. At this time, it is preferable to apply a black paint to the surface of the outer ring 32 to detect the surface temperature in order to increase the emissivity because of using a radiation thermometer. When contact fatigue damage occurs on the surface of the part 1, the surface temperature of the outer ring 32 changes, so from the change point or change temperature, the moment when contact fatigue damage occurs, and further contact fatigue damage occurs. Signals before and after the time can be detected with high accuracy. In addition, hydrogen is charged (contained) in the component 1 by the hydrogen charging step (S10), and due to the deterioration of the material of the component, the component 1 is completed in a shorter time than the normal case where hydrogen is not charged. Contact fatigue damage can occur. Therefore, it is possible to easily detect and record the change over time of the output signal such as the above-mentioned temperature for the entire time from the start of the test to the occurrence of contact fatigue damage.

  FIG. 10 is a schematic diagram showing a situation where a sound signal generated by a component charged with hydrogen is detected. For example, in order to detect a change over time of a sound signal generated by the inner ring 31 of the fixed type constant velocity universal joint 100, as shown in FIG. 10, an ultrasonic microphone 8 as a sound collector is installed. Then, while continuously contacting the inner ring 31 in the step of continuous use (S20), the ultrasonic microphone 8 detects and records a change in sound signal generated by the inner ring 31 over time. At this time, for example, a recording monitor (storage device) (not shown) is preferably connected to the ultrasonic microphone 8. When contact fatigue damage occurs on the surface of the inner ring 31, a change occurs in the sound generated by the surface. Therefore, the signal at the moment when the contact fatigue damage occurs, such as the change point and the frequency and amplitude of the changed sound wave, is obtained. It can be detected with high accuracy. In this case, the inner ring 31 is charged (contained) with hydrogen, and contact fatigue damage can be caused to the inner ring 31 in a shorter time than usual due to the deterioration of the material of the parts. Note that a microphone having a lower upper limit frequency that can be measured than the ultrasonic microphone 8 may be used as long as the sound frequency detected when contact fatigue damage occurs can be detected depending on the material and configuration of the inner ring 31.

  FIG. 11 is a schematic diagram illustrating a situation in which a transmission error of a signal generated by a component charged with hydrogen is detected. For example, when contact fatigue damage occurs in the ball 33 of the fixed type constant velocity universal joint 100, if it is desired to analyze how the constant velocity property is disturbed, the apparatus shown in FIG. 11 can be used. preferable. As shown in FIG. 11, the same ring-type rotary encoder 120 is fitted to the shaft 37 of the sliding type constant velocity universal joint 200 (input side) and the shaft 36 of the fixed type constant velocity universal joint 100 (output side). Let Then, the output difference of the encoder between the input side and the output side is calculated by the arithmetic unit 130 and the transmission error is measured. Then, the FFT 140 shown in FIG. Each component calculated by Fourier transform, such as the next component, can be extracted.

  By using the detection method described above, if a rolling contact fatigue test is performed on the component 1 of the fixed type constant velocity universal joint 100 containing hydrogen by being charged with hydrogen, the hydrogen is not normally charged. Contact fatigue damage can be caused in a shorter time than when a rolling contact fatigue test is performed using these parts. For this reason, while performing the rolling contact fatigue test, it is possible to continuously detect signals such as sound, temperature and transmission error, so that the change point that occurs to the component at the moment when contact fatigue damage occurs, that is, A signal representing a change can be detected continuously and accurately including before and after the moment when contact fatigue damage occurs. This will be specifically described in Example 1 below.

  A rolling contact fatigue test for actually generating contact fatigue damage on the components of the fixed type constant velocity universal joint was performed according to the procedure of the flowchart shown in FIG. 1 described above. First, a fixed type constant velocity universal joint 100 used as an actual automobile part as shown in FIG. 3 was prepared. Here, the radius of the minimum smooth part of the shaft 35 is 19 mm. The inner ring 31 is made of JIS-SCr420 and carburized and hardened. The outer ring 32 is made of JIS-S53C and induction-hardened on the shaft 36 integrated with the outer ring groove 32A. The ball 33 is made of JIS-SUJ2 and hardened. Was used.

And as a process (S10), the inner ring | wheel 31 of the fixed type constant velocity universal joint 100 was installed in the cathode of the equipment which performs the electrolysis shown in FIG. Solution 5 is electrolyzed at a current density of 1 mA / cm ² for 20 hours using a 0.05 mol / L sulfuric acid aqueous solution with 1.4 g / L of thiourea added as a catalyst poison. Thus, hydrogen was contained in the inner ring 31. Here, only the inner ring 31 contains hydrogen, and the related outer ring 32 and balls 33 did not contain hydrogen. Under high load conditions that give a torque of 540 Nm, which will be described later, contact fatigue damage occurs in the inner ring 31. Based on the reason that it is easy. Immediately thereafter, the inner ring 31 was subjected to a lapping process to reduce the surface roughness, and a process of removing thin corrosion products covering the surface of the inner ring 31 by immersing in an acidic aqueous solution for a long time was performed.

  Thereafter, a rolling contact fatigue test shown in FIG. 9 was immediately performed as a step (S20). Specifically, first, as shown in FIGS. 3 and 4, the inner ring 31 charged with hydrogen and the ball 33 are incorporated into the outer ring 32. Then, a predetermined amount of grease is sealed in the outer diameter portion of the outer ring 32 in order to improve lubricity in which the balls 33 roll on the rolling surfaces which are the surfaces of the inner ring groove 31A and the outer ring groove 32A shown in FIG. After applying the black paint, the boot 110 and the shaft 35 were assembled to the fixed type constant velocity universal joint 100 as shown in FIG. Further, as shown in FIG. 8, the shaft 36 integral with the outer ring 32 of the fixed type constant velocity universal joint 100 is connected to one flange of a durability tester (not shown), and the fixed type constant velocity universal joint of the shaft 35 is connected. The end portion not connected to 100 is connected to a sliding type constant velocity universal joint 200, and a predetermined amount of grease is sealed in the sliding type constant velocity universal joint 200 to assemble the boot 110, and the sliding type constant velocity universal joint 200 is assembled. A shaft 37 integral with the outer ring of the universal joint 200 was connected to the other flange of the durability tester (not shown). Then, for example, a radiation thermometer 7 is installed in the vicinity of the outer ring 32 of the fixed type constant velocity universal joint 100 shown in FIG. 8 as shown in FIG.

  In this state, a constant torque of 540 Nm is applied to rotate at 270 rpm while maintaining an operating angle (see FIG. 5) between the shaft 36 and the shaft 35 integral with the outer ring 32 of the fixed type constant velocity universal joint 100 at 6 degrees. The operation for carrying out the rolling contact fatigue test was performed. In the state where this operation was performed, a step of detecting a signal as a step (S21) was performed. Specifically, in Example 1, a rolling contact fatigue test was performed by measuring the surface temperature of the outer ring 32 coated with the black paint described above every 2 minutes. Specifically, the radiation thermometer 7 shown in FIG. 9 detected and recorded the temperature signal of the surface of the outer ring 32 every 2 minutes. Here, although the inner ring 31 is charged with hydrogen, the surface temperature of the outer ring 32 is measured because the inner ring 31 and the ball 33 are covered with the outer ring 32 and the boot 110 and the temperature of the inner ring 31 is measured. This is because it cannot be measured.

  FIG. 12 is a graph showing the results of measuring the temporal change in the temperature of the outer ring surface. In FIG. 12, the horizontal axis indicates the time elapsed after starting the rolling contact fatigue test (the time since the start of operation such as rotation), and the vertical axis indicates the test from the surface temperature of the outer ring 32. The temperature obtained by subtracting the room temperature is shown. The room temperature at which the test was performed was about 25 ° C.

  As shown in FIG. 12, a remarkable increase in the temperature of the surface of the outer ring 32 was observed around 6 hours after the start of the rolling contact fatigue test. That is, at this time, it is considered that contact fatigue damage has occurred. Although not shown, when a normal inner ring that has not been deteriorated by charging with hydrogen is used, it will endure at least several hundred hours and, depending on conditions, thousands of hours. Thus, by charging the inner ring 31 with hydrogen, contact fatigue damage could be generated in the parts of the fixed type constant velocity universal joint 100 in a very short time. In addition, the way of the damage described above was not different from the case where a normal inner ring was used.

  In the second embodiment, as shown in FIG. 11, the shaft 37 integrated with the outer ring of the sliding type constant velocity universal joint 200 (input side) and the outer ring 32 of the fixed type constant velocity universal joint 100 (output side) are integrated. The same ring-type rotary encoder 120 is connected to the shaft 36, the output difference between the encoders on the input side and the output side is calculated by the calculator 130, and the transmission error is measured. Then, the FFT 140 shown in FIG. The rolling contact fatigue test was performed using the method of extracting the fifth component from the second component of the transmission error on the input side and the output side by the above. Here, a 9000-pulse rotary encoder 120 is attached, and the input side and the output side are multiplied by 16 to obtain 144000 pulses. For this reason, the resolution is 9 ″ per pulse.

The prepared fixed type constant velocity universal joint 100 was made of the same material and size as those in Example 1 described above. And as a process (S10), the ball | bowl 33 of the fixed type constant velocity universal joint 100 was installed in the cathode of the equipment which performs the electrolysis shown in FIG. Solution 5 is electrolyzed at a current density of 1 mA / cm ² for 20 hours using a 0.05 mol / L sulfuric acid aqueous solution with 1.4 g / L of thiourea added as a catalyst poison. Thus, hydrogen was contained in the ball 33. Here, in Example 1 described above, hydrogen was contained only in the inner ring 31, whereas in Example 2, hydrogen was contained in the ball 33 because the ball 33 was contact fatigue damaged under low load conditions. Based on the reason that is easy to occur. However, as will be described later, the test was performed not under a low load condition but under a high load condition giving a torque of 540 Nm as in Example 1. The reason is to cause contact fatigue damage to the balls 33 as early as possible. Immediately thereafter, a lapping process was performed on the surface of the ball 33 to reduce the surface roughness, and a treatment for removing a thin corrosion product covering the surface of the ball 33 by immersing in an acidic aqueous solution for a long time was performed. .

  Immediately thereafter, a rolling contact fatigue test shown in FIG. 11 as a step (S20) was performed. Specifically, first, as shown in FIGS. 3 and 4, the ball 33 charged with hydrogen and the inner ring 31 are incorporated into the outer ring 32. Then, after the ball 33 encloses a predetermined amount of grease in order to improve the lubricity of rolling on the rolling surface which is the surface of the inner ring groove 31A and the outer ring groove 32A shown in FIG. 3, as shown in FIG. A boot 110 and a shaft 35 are assembled to the fixed type constant velocity universal joint 100. Further, as shown in FIG. 8, the shaft 36 integral with the outer ring 32 of the fixed type constant velocity universal joint 100 is connected to one flange of a durability tester (not shown), and the fixed type constant velocity universal joint of the shaft 35 is connected. The end on the side not connected to 100 was connected to the sliding type constant velocity universal joint 200. A predetermined amount of grease is sealed in the sliding type constant velocity universal joint 200 and the boot 110 is assembled. The shaft 37 integrated with the outer ring of the sliding type constant velocity universal joint 200 is connected to the other end of the durability tester (not shown). Connected to the flange. 11, the shaft 36 integral with the outer ring 32 of the fixed type constant velocity universal joint 100 and the shaft 37 integral with the outer ring of the sliding type constant velocity universal joint 200 are the same as shown in FIG. The ring-type rotary encoder 120 was connected, the arithmetic unit 130 was connected to the main body of the rotary encoder 120, and the FFT 140 was further connected.

  In this state, an operation for performing a rolling contact fatigue test of the fixed type constant velocity universal joint 100 was performed. The rolling contact fatigue test in Example 2 mainly includes an operation stage as a process (S20) and a measurement stage as a process (S21). In the operation stage mainly as the step (S20), the operating angle (see FIG. 5) formed by the shaft 36 and the shaft 35 integral with the outer ring 32 of the fixed type constant velocity universal joint 100 is maintained at 6 degrees, and 540 Nm. An operation for applying a constant torque and rotating at 270 rpm and performing a rolling contact fatigue test was performed for 1 hour. In the measurement stage mainly as the step (S21), the operating angle is increased to 15 degrees, the torque of the fixed type constant velocity universal joint 100 is decreased to 30 Nm, and the rotational speed is decreased to 70 rpm. Based on the output difference between the sliding type constant velocity universal joint 200 side) and the output side (fixed type constant velocity universal joint 100 side), the transmission error was measured over 2 minutes.

  The above-described period of 1 hour for the operation stage and 2 minutes for the measurement stage was repeated a plurality of times, and the change over time in the sum of the transmission error from the rotation secondary component to the fifth component was measured at each measurement step. FIG. 13 is a graph showing the results of measuring the change in transmission error over time. In FIG. 13, the horizontal axis indicates the time elapsed after starting the rolling contact fatigue test (the time since the start of operation such as rotation), and the vertical axis indicates the rotation secondary component of the transmission error detected by the FFT 140. To the fifth order component. From FIG. 13, the value of the sum of the transmission error from the rotation secondary component to the fifth component increases 19 hours after starting the rolling contact fatigue test, and contact fatigue damage occurs at this point. I understand that. As described above, when a normal inner ring that has not been deteriorated by charging with hydrogen is used, it can endure at least several hundred hours and, depending on conditions, thousands of hours. From this, it was possible to cause contact fatigue damage to the parts of the fixed type constant velocity universal joint 100 in a very short time by charging the balls 33 with hydrogen. In addition, the way of the damage described above was not different from the case where a normal inner ring was used.

  From the above, for example, the inner ring 31, the outer ring 32, and the inner ring 31, which cause contact fatigue damage because they reciprocate while rolling on the rolling surfaces that are the surfaces of the inner ring groove 31 A and the outer ring groove 32 A shown in FIG. 3 and FIG. It can be seen that the balls 33 can cause contact fatigue damage to the test parts in a shorter time than usual, that is, with high efficiency due to the influence of hydrogen being charged. The short time here is, for example, 6 hours or 19 hours as described above, which is an extremely short time compared to the case of normal parts not charged with hydrogen (several hundred to several thousand hours). In such a short time, it is easy to continuously detect and record the above-described temperature, sound, and transmission error signals throughout the test time. Therefore, changes in the signal until contact fatigue damage occurs, changes in the signal at the time of occurrence of the damage, and the like can be recorded in detail. In addition, by charging hydrogen and degrading the material of the test part, contact fatigue damage can be caused in a shorter time than usual, but the manner of damage is not different from the normal case. Therefore, by charging hydrogen, it is possible to accurately reproduce a signal representing a change that occurs at the moment when contact fatigue damage occurs in a shorter time than usual. Therefore, by using the detection method according to the present invention, it is possible to construct a highly reliable method for detecting contact fatigue damage.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  In the present invention, when a fixed type constant velocity universal joint is continuously used, a change point that occurs with respect to a part of a part where contact fatigue damage occurs due to repeated contact, that is, a signal indicating the change with high accuracy, and It is particularly excellent as a technique for detecting in a short time with high efficiency.

It is a flowchart which shows the procedure of the process of the detection method in embodiment of this invention. It is the schematic which shows the state installed on the same conditions as the conditions on which a fixed type constant velocity universal joint is used. It is a schematic sectional drawing which shows the structure of a fixed type constant velocity universal joint. It is a schematic sectional drawing in alignment with line segment IV-IV of FIG. FIG. 4 is a schematic cross-sectional view showing a state where the fixed type constant velocity universal joint of FIG. 3 forms an angle. It is the schematic which shows the state which charges hydrogen to components by electrolysis. It is the schematic which shows the state which charges hydrogen to components by immersing in aqueous solution. It is the schematic which shows the state which assembled | assembled the prepared fixed-type constant velocity universal joint actually. It is the schematic which shows the condition which detects the signal of the temperature of the components charged with hydrogen. It is the schematic which shows the condition which detects the signal of the sound which the components charged with hydrogen generate. It is the schematic which shows the condition which detects the transmission error of the signal which the components charged with hydrogen generate. It is a graph which shows the result of having measured the time-dependent change of the temperature of the surface of an outer ring. It is a graph which shows the result of having measured the time-dependent change of transmission error.

Explanation of symbols

  1 part, 5 solution, 6 aqueous solution, 7 radiation thermometer, 8 ultrasonic microphone, 31 inner ring, 31A inner ring groove, 32 outer ring, 32A outer ring groove, 33 balls, 34 cage, 35 axes, 36 axes, 37 axes, 100 fixed Type constant velocity universal joint, 110 boot, 120 rotary encoder, 130 calculator, 140 FFT, 200 Sliding type constant velocity universal joint.

Claims (9)

It is a detection method that detects the change over time that occurs when contact fatigue damage occurs in a bench test of a fixed type constant velocity universal joint.
Charging the fixed type constant velocity universal joint with hydrogen;
The fixed type constant velocity universal joint charged with hydrogen comprises a step of detecting a signal output in the process of causing contact fatigue damage. In the process of charging hydrogen to the fixed type constant velocity universal joint,
The detection method according to claim 1, wherein hydrogen is charged to the fixed type constant velocity universal joint by performing electrolysis in a solution obtained by adding thiourea as a catalyst poison to a dilute sulfuric acid aqueous solution.   The detection method according to claim 2, wherein the concentration of the thiourea in the solution is 1.2 g / L or more and 1.4 g / L or less. In the process of charging hydrogen to the fixed type constant velocity universal joint,
The detection method according to claim 1, wherein hydrogen is charged to the fixed type constant velocity universal joint by performing electrolysis in a solution obtained by adding ammonium thiocyanate as a catalyst poison to an aqueous sodium chloride solution.   The detection method according to claim 4, wherein a concentration of the ammonium thiocyanate in the solution is 2.5 g / L or more and 3 g / L or less. In the process of charging hydrogen to the fixed type constant velocity universal joint,
The hydrogen is charged to the fixed type constant velocity universal joint by performing electrolysis in a solution obtained by adding sodium sulfide nonahydrate as a catalyst poison to an aqueous sodium hydroxide solution. Detection method.   The detection method according to claim 6, wherein the concentration of the sodium sulfide nonahydrate in the solution is 0.8 g / L or more and 1 g / L or less. In the process of charging hydrogen to the fixed type constant velocity universal joint,
The detection method according to claim 1, wherein the fixed type constant velocity universal joint is charged with hydrogen by being immersed in an aqueous solution of ammonium thiocyanate.   The detection method according to claim 8, wherein a concentration of the ammonium thiocyanate in the solution is 5% by mass or more and 20% by mass or less.

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