JPS6310777B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a testing machine for measuring the durability strength or sliding friction force of a joint portion by repeatedly applying loads from multiple axes to a ball joint, for example.

Figure 1 shows the schematic configuration of a conventional ball joint durability testing machine.

1 is a linear actuator connected to the body part 3 side of the test piece ball joint 2, and 4 is a swing actuator connected to the ball part 5 in a direction perpendicular to this.

The linear actuator 1 applies a sinusoidal excitation force to the ball part 5 from the horizontal axis direction, and the load is detected by the load cell 7.
Further, the swing actuator 4 reciprocates (swings) the connecting shaft 8 connected to the ball portion 5 through a coupling 9 and a torque detector 10 with a sinusoidal excitation force over a constant rotation angle range. The durability test of the ball joint 2 is conducted with a predetermined rotational friction force generated in the joint portion between the ball portion 5 and the body portion 3 in this manner.

In this case, the frictional force is detected by the torque detector 10 as torsional resistance of the connecting shaft 8. For example, when the generated frictional force does not reach a set value, this is adjusted by increasing the load on the linear actuator 1. .

However, in this test machine, it was not possible to apply complex two-dimensional frictional motion to the rotating part of the ball joint 2 (rotational motion centered on the connecting shaft 8 perpendicular to the body part 3) was not possible. In some cases, the durability test was conducted under conditions far removed from the conditions under which ball joint 2 is actually used.

Further, in measuring the frictional force, the torque detector 10 is easily influenced by the moment of inertia of the connecting shaft 8, etc., so the accuracy error is large.

The present invention was proposed to solve such problems.

Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 2 to FIG.
2 is rotatably supported around its both end shaft portions 23A and 23B.

One shaft portion 23A is keyed to a drive shaft 24A of a first swing actuator (rotary hydraulic actuator) 24 attached to the support bracket 21, and is reciprocated by the actuator 24 within a predetermined angular range.

Shaft portion 2 perpendicular to the rotational axis of the first yoke 22
A second yoke 25 with rotation axes at 6A and 26B
is arranged inside the first yoke 22, and its shaft portions 26A and 26B are rotatably supported by the first yoke 22.

A swing actuator (rotary hydraulic actuator) fixed to the first yoke 22
27 drive shafts 27A are keyed to one shaft portion 26A, and the actuator 27 causes the second yoke 25 to reciprocate within a predetermined angular range.

A mounting jig 32 for holding the ball portion 31 of the ball joint 30 under test is provided on the second yoke 25 so as to pass through the rotational axis of the first yoke 22 . In this case, the ball part 3
The center of the yokes 22 and 25 are set so that their centers are perpendicular to the rotation axes of the yokes 22 and 25.

The ball joint 3
A linear actuator (hydraulic cylinder) 34 for vibrating the body portion 33 of the yokes 22 and 25 is arranged on an axis perpendicular to the rotational axes of both the yokes 22 and 25, as shown in FIG.

The operation of this linear actuator 34 is basically the same as that of the conventional example, but the drive rod 35 that holds the body part 33 is equipped with a load cell 36 that detects the load in the axial direction, and a load cell 36 that detects the load in the direction perpendicular to the axis. A two-component force meter 37 for detection is provided.

The load cell 36 and the two-component force meter 37 are screwed together in series as shown in FIG. 4, allowing fine adjustment of the initial position.

The system is constructed as described above, and its operation will be explained next.

Control hydraulic pressure is supplied to the swing actuators 24, 27 and the linear actuator 34 via an electro-hydraulic servo valve, and the actuators 24, 27 and the linear actuator 34 reciprocate and rotate with a sine wave of a predetermined frequency.

Therefore, the first yoke 22 reciprocates around the axis X, and along with this, the second yoke 2
5 performs reciprocating rotation about the axis Y in addition to movement about the axis X.

As a result, the ball portion 31 of the ball joint 30 attached to the second yoke 25 generates a two-dimensional rotational movement in which it reciprocates around the X-axis and also reciprocates around the Y-axis.

On the other hand, when the linear actuator 34 to which the body part 33 is attached is vibrated in the Z-axis direction perpendicular to the X and Y axes, the ball part 31 and the body part 33
A rotational frictional force is generated between the The acting force of the linear actuator 34 may be applied reciprocatingly in the direction of the axis Z, or may be gradually increased or decreased only in one direction as a static load.

In this way, the durability test is performed while imparting two-dimensional rotational motion to the joint portion of the ball joint 30. The frictional force generated in the rotating portion at this time is determined by the two-component force meter 37 and the load cell 36. It is determined by detecting the load and measuring the moment applied to the body portion 33.

However, to be precise, the linear actuator 34
It is necessary to correct the moment generated due to the eccentricity of the drive rod 35 and the moment error due to the difference in operating point.

If the detected friction force deviates from the set value, adjust the load on the linear actuator 34 to match the set value, and in this state, the swing actuator 2
The oscillation operations of 4 and 27 are continued for a predetermined period of time.

Note that the moment is calculated using a normal method, so a detailed description thereof will not be provided.

As described above, according to the present invention, rotational frictional force can be imparted to the ball joint from the secondary direction, and durability tests can be conducted using load characteristics that more closely approximate actual usage conditions. can be used to improve test accuracy.

In addition, when measuring the rotational friction force generated in the ball joint, a two-component force meter and load cell are installed on the linear actuator side, so it is almost unaffected by the moment of inertia of the mounting jig, improving measurement accuracy. There is also the effect of

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional device, FIG. 2 is a front view showing an embodiment of the present invention, FIG. 3 is a side view, and FIG.
The figure is a perspective view of essential parts. 20...Support stand, 21...Bracket, 22...
...first yoke, 24...swing actuator,
25... Second yoke, 27... Rocking actuator, 30... Ball joint, 31... Ball section, 33... Body section, 34... Linear actuator, 36... Load cell, 37... Bicomponent force meter.

Claims (1)

[Claims] 1. A first yoke is rotatably supported on a support base, a first swing actuator is provided for reciprocating the yoke, and a rotational axis of the first yoke is provided inside the first yoke. A second yoke with orthogonal rotation centers is rotatably mounted, and a second swing actuator for reciprocating the second yoke is provided on the first yoke. A linear actuator that passes through the intersection and reciprocates in a direction orthogonal to both axes is installed, and a load cell that detects the load in the axial direction is installed in the middle of the drive rod that holds the linear actuator specimen. 1. A durability testing machine comprising: a two-component force meter for detecting a load in a direction perpendicular to the first yoke; and a mounting jig for holding a specimen on the second yoke.