JPH09288046A - Wheel-durability testing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wheel-durability testing apparatus by which the generation of an initial crack in the peripheral edge part of a bolt hole can be detected by a method wherein one end part of a movement arm is connected to the hub mounting part of a wheel by using a coupling belt and a strain gage is bonded to the peripheral edge part of the belt hole. SOLUTION: A strain gage 40 is bonded to the peripheral edge part of a belt hole 12 at a wheel 10, and a movement arm 25 is connected to the hub mounting part 11 at the wheel 10 by using a coupling bolt 30 and a but 31. The wheel 10 is centered with reference to the rotation center A of a rotary table 21 by using a guide ring 24, it is held to the table 21 by a pressure jig 23, and also the rotation center of the arm 25 is centered with reference to the rotation center A. A control part 46 starts a drive means 47 so as to turn the wheel 10. A load F at right angles to an axial direction is applied to the upper end part of the arm 25, and a local stress is generated in the peripheral edge part of the bolt hole 12. As a result, when a crack is generated, the gage 40 in the peripheral edge part of bolt hole 12 is disconnected, the control part 46 operates a switch 48 by a disconnection signal, and the means 47 is stopped automatically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel endurance test apparatus used for endurance tests of automobile wheels.

[0002]

2. Description of the Related Art An automobile wheel is subjected to a durability test in order to determine whether or not it meets a required strength standard. FIG. 5 shows a conventional wheel durability test apparatus. In FIG. 5, a wheel 2 is held on a rotary table 1 by a holding jig 3. The wheel 2 is centered by a guide ring 4 attached to the rotary table 1. The lower end of the moment arm 5 is connected to the hub mounting portion of the wheel 2 by a connecting bolt 6. The connecting bolt 6 is inserted into a bolt hole 7 formed in the hub mounting portion of the wheel 2. During the durability test, a load F is applied to the upper end of the moment arm 5 in the direction perpendicular to the axial direction. A sensor 8 for detecting tilting of the moment arm 5 is arranged near the upper end of the moment arm 5. The sensor 8 is electrically connected to a driving unit such as a motor (not shown) that drives the rotary table 1 to rotate. The sensor 8 is fixed to the moment arm 5 at a constant distance depending on the type of wheel and the load applied.

During the durability test using the above apparatus, the wheel 2 is rotated around the axis by the rotary table 1. While the wheel 2 is rotating, the load F is applied to the moment arm 5 in the direction perpendicular to the axial direction.
A local stress is generated at the connecting portion with the moment arm 5 and a crack is generated from the peripheral portion of the bolt hole 7. When a crack in the peripheral portion of the bolt hole 7 progresses and the hub mounting portion of the wheel 2 is damaged, the moment arm 5 falls in the load applying direction. Since the tilt of the moment arm 5 is detected by the sensor 8, the rotation of the turntable 1 can be stopped based on the detection signal of the sensor 8.

[0004]

However, the durability test apparatus of FIG. 5 has the following problems. The durability strength of the wheel 2 is evaluated by the rotation speed at the time when a crack is generated in the hub mounting portion.
In the case of the wheel 2, since the crack of the hub mounting portion of the wheel 2 is greatly developed and the hub mounting portion cannot be collapsed unless the hub mounting portion is damaged, the sensor 8 cannot detect the initial crack. Therefore, it is necessary to stop the device once during the durability test and confirm whether or not an initial crack has occurred. Since the occurrence of the initial crack and the stop time of the rotary table are different, the wheel travel distance (table rotation speed) when the initial crack occurs is ambiguous. Since the device does not stop at the time of the initial crack, the durability test time increases. Therefore, the load of the durability test apparatus becomes large, and a large number of durability test apparatuses are required to perform the durability test of various wheels. An object of the present invention is to provide a wheel durability test device capable of detecting the occurrence of an initial crack from the peripheral portion of a bolt hole in a wheel durability test.

[0005]

The wheel durability test apparatus according to the present invention for achieving this object is as follows.
is there. A rotary table that holds the wheel, a drive means that drives the rotary table to rotate, and a hub mounting portion of the wheel that is held on the rotary table, one end of which is connected through a connecting bolt, and the other end of which is axial. A wheel durability test apparatus comprising: a moment arm that receives a load in a direction perpendicular thereto, and a strain gauge adhered to a peripheral portion of a bolt hole into which the connecting bolt of the hub mounting portion is inserted.

In the wheel durability test apparatus according to the present invention,
While the wheel is rotating, a load is applied to the other end of the moment arm in a direction perpendicular to the axial direction. A crack develops from the periphery of the hole. Since the strain gauge is adhered to the peripheral portion of the bolt hole, if a crack occurs in the peripheral portion of the bolt hole, the resistance wire of the strain gauge is broken or its resistance value changes significantly. Therefore, it becomes possible to detect the occurrence of the initial crack by the detection signal from the strain gauge.

[0007]

1 to 4 show an embodiment of a wheel durability test apparatus according to the present invention. FIG.
Shows a wheel durability test apparatus 20. The wheel durability test apparatus 20 has a rotary table 21.
The wheel 10 is held on the rotary table 21 by a holding jig 23. The wheel 10 is the turntable 2
A guide ring 24 provided on the centering unit 1 centers the center of rotation A of the rotary table 21. The lower end of the moment arm 25 is connected to the hub mounting portion 11 of the wheel 10 by a connecting bolt 30 and a nut 31. The moment arm 25 extends upwards,
The lower end portion is formed on the flange 26 that bulges outward in the radial direction. As shown in FIG. 2, the connection bolt 30 has a lower portion fixed to the flange portion 26, and an upper portion formed on the wheel 1.
It is inserted into the bolt hole 12 formed in the hub mounting portion 11 of No. 0. A nut 31 is screwed into the threaded portion of the connecting bolt 30 protruding from the bolt hole 12. The load F in the direction perpendicular to the axial direction is applied to the upper end of the moment arm 25 by the pressing means 32 during the durability test.

A quenching plate 35 is attached to the flange 26 of the moment arm 25. The quenching plate 35 is arranged at a position facing the bolt hole 12 of the wheel 10. The quenching plate 35 is formed with a recess 36 that is recessed downward in order to prevent interference with a strain gauge 40 described later. A strain gauge 40 having a thickness of 1 mm or less is adhered to the peripheral portion of the bolt hole 12 of the wheel 10. Strain gauge 40
Has a resistance wire whose electric resistance changes due to strain. As shown in FIG. 4, the strain gauge 40 has a donut shape in a plan view, and has a hole 41 for inserting the connecting bolt 30 in the center thereof. Strain gauge 4
A lead wire connected to the resistance wire is provided on the outer peripheral portion of 0. As shown in FIG. 2, the strain gauge 40 is
It is arranged so as to enter the recess 36 of the quenching plate 35. This prevents damage to the strain gauge 40 due to interference with the flange 26 when the wheel 10 and the moment arm 25 are connected.

A slip ring 45 is attached to the rotary shaft 21a of the rotary table 21. The strain gauge 40 is electrically connected to the control unit 46 via the slip ring 45. The slip ring 45 is composed of a conductive ring fixed to the rotating shaft 21a and a conductive brush that contacts the conductive ring. The drive means 47 is
For example, the rotary table 21 is composed of a motor.
Is connected to the rotary shaft 21a. Turntable 21
Is driven to rotate about the axis by the drive means 47. The drive means 47 is started or stopped by the switch 48. The crack generation detection signal from the strain gauge 40 is input to the switch 48 via the slip ring 45 and the control unit 46, and the switch 48 stops the driving means 47. The wheel durability test apparatus 20 has a display (not shown) that displays the cumulative number of rotations of the rotary table 21 from start to stop.

Next, the operation of the wheel durability test apparatus will be described. First, the strain gauge 40 is bonded to the peripheral edge of the bolt hole 12 of the wheel 10 with an adhesive or the like. Next, the hub mounting portion 11 of the wheel 10
In addition, the moment arm 25 is connected by a connecting bolt 30 and a nut 31. The wheel 10 to which the moment arm 25 is connected is centered with respect to the rotation center A of the rotary table 21 by the guide ring 24, and then held on the rotary table 21 via the holding jig 23. As a result, the rotation center of the moment arm 25 is also centered on the rotation center A of the turntable 21. When the mounting of the wheel 10 on the rotary table 21 is completed, the drive unit 47 is activated by the control unit 46, and the wheel 10 is driven.
Rotates about its axis.

While the wheel 10 is rotating, a load F is applied to the upper end of the moment arm 25 in the direction perpendicular to the axial direction.
A local stress is generated at the connecting portion with and a crack is generated from the peripheral portion of the bolt hole 12. At the periphery of the bolt hole 12,
Since the strain gauge 40 is bonded, the bolt hole 1
If a crack occurs at the peripheral edge of 2, strain gauge 4
The resistance wire of 0 is broken. Since the strain gauge 40 is electrically connected to the control unit 46 via the slip ring 45 provided on the rotary table 21 side, the control unit 4 is based on the detection signal (disconnection signal) from the strain gauge 40.
6 operates, and the drive means 47 is automatically stopped by the operation of the switch 48 according to a command from the control unit 46. Therefore, the rotation of the rotary table 21 can be automatically stopped at the same time when the initial crack is generated in the peripheral portion of the bolt hole 12.
Since the rotating table 21 and the wheel 10 have the same number of rotations, by reading the cumulative number of rotations at the time when the rotating table 21 stops, the number of rotations of the wheel 10 caused by the initial crack in the peripheral portion of the bolt hole 12 is read. It is possible to specify whether it occurred when you did.

In this embodiment, the drive means 47 is automatically stopped based on the disconnection signal of the strain gauge 40. However, the drive means 47 is automatically stopped based on the change in the resistance value of the strain gauge 40 due to the occurrence of cracks. It may be configured to. Further, by measuring the resistance value of the strain gauge 40 during the durability test, it is possible to analyze the behavior up to the occurrence of cracks. Furthermore, strain gauge 40
By changing the resistance value, etc., it is possible to analyze cracks and breaks in parts other than the periphery of the bolt holes. When the crack generation signal from the strain gauge 40 is detected and the cumulative number of rotations of the rotary table 21 at that time is stored, it is not necessary to automatically stop the rotary table 21.

[0013]

According to the wheel durability test apparatus of the present invention, the following effects can be obtained. A strain gauge is adhered to the periphery of the bolt hole of the wheel, so if a crack occurs at the periphery of the bolt hole during the durability test, the occurrence of an initial crack should be detected by the detection signal from the strain gauge. Is possible. Therefore, based on the detection signal from the strain gauge, it is possible to stop the rotation of the rotary table at the same time when the initial crack is generated in the peripheral portion of the bolt hole. It is possible to easily determine the cumulative number of revolutions (driving distance) of the wheel when the initial crack of the wheel occurs. By measuring the change in the resistance value of the strain gauge, the behavior up to crack initiation can be analyzed. Since the rotation of the rotary table is stopped at the same time when the initial crack is generated, the durability test time can be shortened as compared with the conventional device. Therefore, even when the durability test of various wheels is performed, the number of required durability test devices can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a wheel durability test apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the device of FIG.

3 is a plan view of the device of FIG. 1. FIG.

FIG. 4 is a plan view of a strain gauge in the apparatus shown in FIG.

FIG. 5 is a front view of a conventional wheel durability test apparatus.

[Explanation of symbols]

 10 Wheel 21 Rotary Table 25 Moment Arm 30 Connecting Bolt 35 Quenching Plate 40 Strain Gauge 45 Slip Ring 45 Driving Means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yutaka Ito 9-5, Yonbancho, Chiyoda-ku, Tokyo Topy Industries Co., Ltd.

Claims (1)

[Claims] 1. A rotary table for holding a wheel, a driving means for rotationally driving the rotary table, one end of which is connected to a hub mounting portion of the wheel held on the rotary table via a connecting bolt, and the other end of which is connected to the hub mounting portion. A wheel durability test apparatus comprising: a moment arm whose portion receives a load in a direction perpendicular to an axial direction; and a strain gauge bonded to a peripheral portion of a bolt hole into which the connecting bolt of the hub mounting portion is inserted.