WO2008111691A1

WO2008111691A1 - Device for detecting defects of chassis components in a vehicle

Info

Publication number: WO2008111691A1
Application number: PCT/KR2007/001186
Authority: WO
Inventors: Jin Yong Kim; Ji Hun Park; Han Soo Yun
Original assignee: Il Jin Global Co., Ltd.
Priority date: 2007-03-09
Filing date: 2007-03-09
Publication date: 2008-09-18

Abstract

The present invention relates to a device for detecting defects of chassis components in a vehicle. The objective of the present invention is to provide a device for detecting defects of chassis components. The device detects them with an algorithm using acceleration signals detected at an outer ring of a hub bearing or a knuckle while driving the vehicle The present invention provides a specific means, comprising: a data input portion for receiving 3 axis vibrating acceleration signals (71 ) and wheel speed signals (72) of each wheel at an outer ring of a hub bearing or a knuckle; a signal conditioner (73) including a low pass filter and an amplifier for receiving the signals; a data arithmetic unit (74) having an algorithm for detecting defects of each chassis component using the signals; and a defect display unit (77) for displaying the defects signals from the detecting defects portion with light and graphic.

Description

DEVICE FOR DETECTING DEFECTS OF CHASSIS COMPONENTS IN A

VEHICLE

TECHNICAL FIELD

The present invention generally relates to a device for detecting defects of chassis components in a vehicle. More particularly, the present invention relates to a device for detecting defects of chassis components (e.g., hub bearing, ball joint, toe alignment, wheel balance, etc.) in a vehicle and providing signals representing such defects to a driver, wherein the signals are oscillation phenomena generated in the defective chassis components and measured in real time by acceleration sensors mounted to a hub bearing or a knuckle.

BACKGROUND ART

Generally, the chassis components of a vehicle are constructed by wheels, brake disks, brake pads, hub bearing units, a driving shaft, steering knuckles, springs, a shock absorber, linkages, joints and a frame.

Fig. 1 is a perspective view showing conventional chassis components of a vehicle.

As shown in Fig. 1, the conventional chassis components comprise the following: a hub bearing unit (2) supporting loads generated while a vehicle is moving (i.e., rotation, upper-lower load and forward-backward load of the vehicle) and loads generated while the vehicle is turning (e.g., horizontal and vertical loads in Z axis), wherein a tire (1) is coupled to a periphery of the hub bearing unit (2); a knuckle (3) supporting the hub bearing unit (2); a lower control arm (5) and an upper control arm (6), which connects between the knuckle (3) and a body of the vehicle with ball joints (4); and a shock absorber (8) having a coil spring (7) positioned at a periphery thereof for absorbing shocks to the body.

The hub bearing, ball joint and tires are primary components that construct a chassis system of the vehicle. Performances of the vehicle (e.g., driving comfort, control, etc.) are influenced by such a system. Fig. 2 is a schematic view showing a construction of a conventional hub bearing unit of the vehicle. As shown in Fig. 2, the conventional hub bearing unit includes a hub (1 1), an outer ring flange (12) mounted at one side of the hub, and a wheel speed sensor (13) for detecting a speed of the wheel.

Further, Fig. 3 is a schematic view showing a structure of the wheel speed sensor of the conventional vehicle. As shown in Fig. 3, the wheel sensor (21) for said vehicle has circuit components (24) on a substrate (23). Further, a wheel speed sensor (22) and an acceleration sensor (25) are mounted on one side thereof.

The vehicle cannot drive when the hub bearing (2) exceeds a fatigue limit while driving, thereby causing a minute burning of a track (15). While the vehicle drives, a gap (22) of a ball (21) of a ball joint (4) increases gradually. If the gap becomes larger than a critical size, then noise and vibration occur. In the worst case scenario, disjoint, which can lead to dangerous situations such as a vehicle body collapse, can occur.

As shown in Fig. 5, if toe alignments of tires are misaligned, then this will cause the vehicle to incline and the tires to wear out unevenly. In a high speed driving, if a rotating balance (wheel balance) of tires is not matched, then the handling of the vehicle becomes difficult, as shown in Fig. 6. Such defects in the tires cause vibration noises and early abrasion of suspension parts.

There is disclosed a prior application (Korean Patent Application No. 10-1988- 0006663) entitled "APPARATUS FOR DETECTING A FAILURE IN BEARINGS," which is directed to detecting bearing defects.

The above application relates to a method of diagnosing bearing failure by a critical value of acoustic signals when the signals exceed the critical condition. However, the method of said application is disadvantageous since it cannot be easily applied to conditions subject to various noises produced when driving the vehicle.

Further, U.S. Patent No. 6,695,483, which is entitled "SENSOR AND ROLLING BEARING APPARATUS WITH SENSOR," is directed to detecting a bearing.

The invention disclosed in said patent relates to self-diagnosis using an acceleration sensor and an embedded thermometer. However, it discloses only a general idea without providing any specific algorithm for detecting bearing defects.

There has been no suggestion in the art in relation to detecting the defects of chassis components (except hub bearing).

DISCLOSURE TECHNICAL PROBLEM

Accordingly, the present invention is directed to improving the driver safety by diagnosing whether or not the chassis components are defective.

The objective of the present invention is to provide a device for detecting the defects of chassis components. Such a device conducts a diagnosis with an algorithm for assessing the defects of chassis components by using acceleration signals detected at an outer ring of a hub bearing or a knuckle while the vehicle is moving. If the chassis components are detected to have defects, then a display unit will notify such defects to the driver.

TECHNICAL SOLUTION

To achieve the above objective, the present invention provides a concrete means comprising the following: a data input portion for receiving 3 axis acceleration signals of vibration (71) and wheel speed signals (72) of each wheel at an outer ring of a hub bearing or a knuckle; a signal conditioner (73) including a low pass filter, amplifier and the like in order to receive the signals after removing a noise; a data arithmetic unit (74) having an algorithm for diagnosing defects of each chassis component by using the signals; and a defect display unit (77) for displaying the defects signal transmitted from the defects diagnosing portion (e.g., lighting system, navigation display, etc.).

ADVANTAGEOUS EFFECTS

In accordance with the present invention, the device for detecting defects of chassis components in a vehicle can easily diagnose said defects by using acceleration signals and speed signals detected at the outer ring of the hub bearing while driving.

Whether the chassis components have a defect is determined by such a diagnosis. The diagnosis is notified to the driver by a diagnostic algorithm. Thus, the present invention provides a useful effect in which the driver can easily and conveniently understand whether or not the vehicle has defects.

DESCRIPTION OF DRAWINGS Fig. 1 is a schematic view showing a construction of a prior art suspension in a vehicle.

Fig. 2 is a schematic view showing a construction of a prior art hub bearing in a vehicle.

Fig. 3 is a schematic view showing a construction of a prior art wheel speed sensor in a vehicle.

Fig. 4 is a schematic view showing a construction of a prior art ball joint in a vehicle.

Fig. 5 is a view showing an abrasion of tires having defects in a toe alignment. Fig. 6 is a view showing an oscillation of tires having defects in a wheel balance. Fig. 7 is a block diagram of a device for detecting defects of chassis components according to the present invention.

Fig. 8 is a flow chart of an algorithm relating to detecting defects in a device for detecting defects of chassis components according to the present invention.

Fig. 9 shows a comparison between a normal signal and a defective signal in a hub bearing according to the present invention (in time axis).

Fig. 10 shows a comparison between a normal signal and a defective signal in a hub bearing according to the present invention (in frequency axis).

Fig. 1 1 shows a comparison between a normal signal and a defective signal in a ball joint according to the present invention (in time axis). Fig. 12 shows a comparison between a normal signal and a defective signal in a ball joint according to the present invention (in frequency axis).

Fig. 13 shows a comparison between a normal signal and a defective signal in a toe alignment according to the present invention (in time axis).

Fig. 14 shows a comparison between a normal signal and a defective signal in a toe alignment according to the present invention (in frequency axis).

Fig. 15 shows a comparison between a normal signal and a defective signal in a wheel balance according to the present invention (in time axis).

Fig. 16 shows a comparison between a normal signal and a defective signal of a wheel balance according to the present invention (in frequency axis).

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Fig. 7 is a block diagram of a device for detecting defects of chassis components according to the present invention. Fig. 8 shows an algorithm relating to detecting defects in a device for detecting defects of chassis components according to the present invention. The following describes the algorithm for such detection.

1024 data of 3 axis acceleration signals and wheel speed signals are collected at each wheel over a period of one second (81 1). The RMS (Root-Mean-Square) value of all collected acceleration signals is calculated. It is then estimated whether it is less than IG or not (812). If it is more than IG, then the data will be collected again.

Otherwise, the next step is performed. This step is for estimating whether the road surface is rough such as an unpaved road. The next step is for sorting them out by the driving speed of the vehicle. If the vehicle is faster than 80km/h, then a hub bearing detecting step (813) is performed. If the vehicle is in a deceleration mode, then a ball joint detecting step (814) is performed. If the vehicle is faster than 100km/h, then a step for detecting a toe alignment and a wheel balance (815) is performed. In the other speed range, a data collecting step is performed again. Signals in the steps for detecting the hub bearing, ball joint and toe alignment are filtered by a band pass filter having a bandwidth in 100 to 400Hz (816, 817 and 818). Signals in the step for detecting the wheel balance are filtered by a band pass filter bandwidth within 1 1 to 17Hz (819). The RMS of each filtered signal is calculated in each detecting step and a wheel having the maximum value is also calculated (820 to 827). If the maximum value calculated in the steps for detecting the hub bearing, ball joint and toe alignment is at least 3 times larger than all of the 3 axis acceleration values in all 3 ways, which are diagnostic criteria, then a hub bearing detecting step (828) is performed. Otherwise, the ball joint detecting step and the toe alignment detecting step are performed. If the acceleration signals are increased at least 2 times larger than the criterion values in the ball joint detecting step, then the longitudinal direction (in X axis) signals are transmitted to the next step (829). Otherwise, the step for collecting data is performed again. If the acceleration signals are increased at least 1.2 times larger than the criterion values in the toe alignment detecting step, then the lateral direction (in Y axis) signals are transmitted to the next step (830). Otherwise the step for collecting data is performed again. If the calculated longitudinal direction (in X axis) signals of the maximum wheel are at least 2 times larger than the criterion values in the wheel balance detecting step, then the next step is performed (831). Otherwise, the step for collecting data is performed again. If the signals passing by the criterion values are at least 2 times larger than left and right wheels in the vertical direction (in Z axis) acceleration (832) and at least 2 times larger than front and rear wheels (836), wherein such processes were repeatedly performed 30 times (840) in the hub bearing detecting step, then the hub bearing is assessed to have defects and a defect lamp is then turned on (844). Otherwise, the step for collecting data is performed once again. If the signals passing by the criterion values are at least 1.5 times larger than left and right wheels in the vertical direction (Z axis) acceleration (833) and at least 1.5 times larger than front and rear wheels (837), wherein these processes were repeatedly performed 30 times (841) in the step for detecting the ball joint, then the ball joint is determined to have defects and the defect lamp is then turned on (845). Otherwise, the step for collecting data is performed again. If the signals passing by the criterion values are at least 1.2 times larger than left and right wheels in the lateral direction (in Y axis) acceleration (834) and at least 1.2 times larger than front and rear wheels (838), wherein such processes are repeatedly performed 30 times (842) in the step for detecting the toe alignment, then the toe alignment is determined to be defective and the defect lamp is then turned on (846). Otherwise, the step for collecting data is performed once again. If the signals passing by the criterion values are at least 2 times larger than left and right wheels in the longitudinal direction (in X axis) acceleration (835) and at least 2 times larger than front and rear wheels (839), wherein such processes were repeatedly performed 30 times (843) in the step for detecting the wheel balance, then the toe alignment is determined to be defective and the defect lamp is then turned on (847). Otherwise, the step for collecting data is performed again. Here, the criterion value is determined by an initial steady state (under 1000km driving). The algorithm, the process of comparing the signals to one of the left, right, front and rear wheels over 30 times is for excluding driving conditions such as the vehicle driving on the road in which the left surface is different from the right surface or as the vehicle drives on the road with some abnormal protrusions. Figs. 9 and 10 show comparisons between normal signals (91 , 101) and defective signals (92, 102) in the hub bearing according to the present invention in time axis versus frequency axis, which are detected while the vehicle is moving. The signal is 3 times larger in the high frequency region.

Figs. 1 1 and 12 show comparisons between normal signals (1 1 1 , 121) and defective signals (1 12, 122) in the ball joint according to the present invention in time axis versus frequency axis, which are detected while the vehicle is moving. The signal is 2 times larger in the high frequency region.

Figs. 13 and 14 show comparisons between normal signals (131 , 141 ) and defective signals (132, 142) in the toe alignment according to the present invention in time axis versus frequency axis, which are detected while the vehicle is moving. The signal is 1.5 times larger in the high frequency region.

Figs. 15 and 16 show comparisons between normal signals (151, 161) and defective signals (152, 162) in the wheel balance according to the present invention in time axis versus frequency axis, which are detected while the vehicle is moving. The signal is 2 times larger in the low frequency region.

Claims

1. A device for detecting defects of chassis components in a vehicle, comprising: a data input portion (811) for receiving 3 axis acceleration signals and a wheel speed detected at an outer ring of a hub bearing or a knuckle in each wheel; a signal conditioner for assessing a wheel having a maximum value by calculating a RMS (Root-Mean-Square) of signals (820), the signals having been filtered at 100 to 400 Hz by a band pass filter (816) while the driving speed determined by the inputted signals at the data input portion is faster than 80km/h (813); a defect detecting portion for detecting whether the hub bearing has a defect when all the values of a vertical direction (in Z axis) are at least 3 times larger than a criterion value (828) and are at least 2 times larger than left-right values (832) and a front-rear value (836) while the signal conditioner continuously calculates over 30 times (840); and a defect lamp (844) for displaying a defect signal of the hub bearing transmitted from the defect detecting portion with a light signal.

2. A device for detecting defects of chassis components in a vehicle, comprising: a data input portion (811) for receiving 3 axis acceleration signals and a wheel speed detected at an outer ring of a hub bearing or a knuckle in each wheel; a signal conditioner for assessing a wheel having a maximum value (825) by calculating a RMS (Root-Mean-Square) of signals (821), the signals having been filtered at 100 to 400 Hz by a band pass filter (817) while a driving speed determined by the inputted signals at the data input portion is in a deceleration mode (814); a defect detecting portion for detecting whether the ball joint has a defect when all the values of a longitudinal direction (in X axis) are at least 2 times larger than a criterion value (829) and are at least 1.5 times larger than left-right values (833) and a front-rear value (837) while the signal conditioner continuously calculates over 30 times (841); and a defect lamp (845) for displaying the defect signal of the ball joint transmitted from the defect detecting portion with a light signal.

3. A device for detecting defects of chassis components in a vehicle, comprising: a data input portion (81 1) for receiving 3 axis acceleration signals and a wheel speed detected at an outer ring of a hub bearing or a knuckle in each wheel; a signal conditioner for assessing a wheel having a maximum value (826) by calculating a RMS (Root-Mean-Square) of signals (822), the signals having been filtered at 100 to 400 Hz by a band pass filter (818), while a driving speed determined by the inputted signals at the data input portion is faster than 100km/h (815); a defect detecting portion for detecting whether a toe alignment has a defect when all the values of a lateral direction (in Y axis) are at least 1.2 times larger than a criterion value (830) and are at least 1.2 times larger than left-right values (834) and a front-rear value (838) while the signal conditioner continuously calculates over 30 times (842); and a defect lamp (846) for displaying the defect signal of the toe alignment transmitted from the defect detecting portion with a light signal.

4. A device for detecting defects of chassis components in a vehicle, comprising: a data input portion (81 1) for receiving 3 axis acceleration signals and wheel speed signals detected at an outer ring of a hub bearing or a knuckle in each wheel; a signal conditioner for assessing a wheel having a maximum value (827) by calculating a RMS (Root-Mean-Square) of signals (823), the signals having been filtered at 11 to 17 Hz by a band pass filter (819) while a driving speed determined by the inputted signals at the data input portion is faster than lOOkm/h (815); a defect detecting portion for detecting whether the wheel balance has a defect when all the values of a longitudinal direction (in X axis) is at least 2 times larger than a criterion value (831) and are at least 2 times larger than left-right values (835) and a front-rear value (839) while the signal conditioner continuously calculates over 30 times (843); and a defect lamp (847) for displaying the defect signal of the wheel balance transmitted from the defect detecting portion with a lighting signal.

5. The device of any one of Claims 1 to 4, wherein the data input portion (811) collects 3 axis acceleration signals and wheel speed data at the outer ring of the hub bearing or the knuckle of each wheel every one second, and wherein a number of data of the 3 axis acceleration signals and wheel speed data is 1024 for one second.

6. The device of any one of Claims 1 to 4, wherein the devices are constructed integrally for detecting the defects of the hub bearing, the ball joint, the toe alignment and the wheel balance at a time.