JPH04216432A - Lifetime judging method of frp driving shaft - Google Patents

Abstract

PURPOSE:To prevent a trouble of an FRP driving shaft by measuring the torque and the torsion angle transmitted by the driving shaft, obtaining the relationship therebetween at real time thereby to monitor the change of the rigidity of the driving shaft, and judging that the driving shaft should be changed when the rigidity starts to be decreased. CONSTITUTION:A torque measuring device 9 is mounted to a metallic driving shaft 2 at the side of an engine 1, and a torsion angle measuring device is provided to a flange 6 at the side of an output shaft 8 of an FRP driving shaft 5. When a variable torque is applied to the driving shaft 5, as the repeating number of times is increased, the torsion angle is also increased, resulting in the break of the shaft. Therefore, the relationship between the torque detected by the torque measuring device 9 and the torsion angle detected by the torsion angle detecting device 10 is monitored during driving of the engine, so that the change of the rigidity of the shaft is detected. Accordingly, the degree of the damage of the shaft is evaluated. When the rigidity of the shaft starts to be decreased, the shaft is exchanged. In this manner, the shaft is prevented from being caught in trouble.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining the life of an FRP drive shaft.

0002

2. Description of the Related Art In the case of conventional metal drive shafts, even minute defects can be detected because non-destructive testing techniques such as ultrasonic flaw detection have been established. However, since the FRP drive shaft significantly attenuates ultrasonic waves, such defects cannot be detected. Furthermore, even when using X-rays, the resolution is not very good, so it is not possible to predict destruction in advance.

0003

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lifespan determination method that can detect the degree of damage to an FRP drive shaft and prevent troubles with the drive shaft.

0004

[Means for solving the problem] By measuring the torque and torsion angle transmitted by the FRP shaft and finding the relationship between the two in real time, changes in the rigidity of the FRP drive shaft can be monitored and the rigidity can be detected. Once it started, I knew it was time to replace it.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 1 is an engine. Reference numeral 2 denotes a metal drive shaft on the engine side, which has a flange 3 at its end. Reference numeral 5 denotes an FRP drive shaft, which is connected by a flange 4 to a flange 3 on the engine side metal drive shaft 2 side. Reference numeral 6 denotes a flange on the other end side of the drive shaft, which is connected to a flange 7 on the output shaft 8 side.

Reference numeral 9 denotes a torque measuring device attached to the metal drive shaft 2 on the engine side, and 10 denotes a torsion angle measuring device attached to the flange 6 attached to the output shaft 8 side of the FRP drive shaft 5.

[0007] When a variable torque is applied to an FRP drive shaft, the rigidity of the shaft decreases at any load level when the number of loads exceeds 1/5 to 1/2 of the lifespan leading to failure. To start, even if the same load is applied,
It is clear from the results of the torsion fatigue test that the torsion angle begins to increase gradually (see Figure 2).

[0008] Therefore, when the engine is running, the torque measuring device 9
By constantly monitoring the relationship between the torque and the torsion angle of the FRP drive shaft measured by the torsion angle measuring device 10 and checking whether the rigidity has decreased, it is possible to determine whether or not the FRP drive shaft is damaged. I can confirm it.

FIG. 2 shows the relationship between the torsion angle and the number of repetitions (life) during a torsional fatigue test of an FRP shaft. In FIG. 2, the horizontal axis shows the number of repetitions (logN), the vertical axis shows the twist angle, and shows an example of experimental results using a scale model of an FRP drive shaft. The experimental conditions were a maximum load torque of 250 kg.
f·m, the minimum load torque is 0 kgf·m, and the load frequency as a fluctuating torque is 1 Hz.

As is clear from the figure, as the number of repetitions increases, the twist angle also gradually increases, and failure occurs at the maximum twist angle of 31.54°.

[0011] In this way, the load torque and torsion angle of the FRP drive shaft during driving force transmission are measured, changes in shaft rigidity are detected to evaluate the degree of damage, and if the rigidity begins to decrease, the shaft is By replacing it, it is possible to prevent trouble from occurring.

0012

[Effect] By utilizing the characteristics of the FRP drive shaft being subjected to fluctuating loads until it breaks down and evaluating the degree of damage, it is now possible to prevent problems with the drive shaft.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a rigidity detection system of a lifespan determination method according to the present invention.

FIG. 2 is a graph showing the relationship between the number of repetitions and torsion angle of an FRP shaft.

[Explanation of symbols]

1 Engine 2 Metal drive shaft 3 Flange 4 Flange 5 FRP drive shaft 6 Flange 7 Flange 8 Output shaft 9 Torque measuring device E Torsion angle measuring device

Claims (1)

[Claims] [Claim 1] Changes in the rigidity of the FRP drive shaft were monitored by measuring the torque and torsion angle transmitted by the FRP shaft and determining the relationship between the two in real time, and it was determined that the rigidity of the shaft began to decrease. If so, a method for determining the lifespan of an FRP drive shaft, characterized by determining that it is time to replace it.