JP5973103B1 - Wheel alignment inspection method - Google Patents

Abstract

An object of the present invention is to appropriately inspect the cause of a defect in wheel alignment. The cutting angle of the inner front wheel is measured in a state where the steering wheel is turned to the right so that the outer front wheel has a cutting angle θ1. Next, the turning angle of the inner front wheel is measured with the handle turned to the left so that the outer front wheel has a turning angle θ1. Next, the cutting angles of the outer front wheel and the inner front wheel are measured in a state where the steering wheel is turned to the right so that the outer front wheel has a cutting angle θ2 (> θ1). Next, the cutting angle of the inner front wheel is measured with the handle turned to the left so that the outer front wheel has a cutting angle θ2. The cause of the wheel alignment failure is determined based on the measurement results of these cutting angles. [Selection] Figure 2

Description

  The present invention relates to a wheel alignment inspection method.

  Adjustment of wheel alignment in a vehicle having four wheels such as an automobile is important in order to ensure stability during traveling and to suppress uneven wear of tires. In Patent Document 1, the steering wheel is positioned in a horizontal position and attached to the steering shaft while adjusting the direction of the front wheel based on the assumed direction of the rear wheel, and then the toe of the front wheel and the rear wheel is adjusted.

JP2012-122900A

  The present inventor has found that even when the wheel alignment is adjusted as in Patent Document 1, stability during traveling may not be ensured or uneven wear of the tire may not be effectively suppressed. The reason why the wheel alignment cannot be adjusted appropriately in this way is that the cause of the defect in the wheel alignment cannot be properly grasped, and the cause of the defect cannot be properly eliminated.

  An object of the present invention is to provide a wheel alignment inspection method capable of appropriately inspecting the cause of a defect in wheel alignment.

  The inventor has sought the reason why the cause of the problem in wheel alignment cannot be properly grasped. As a method for inspecting the wheel alignment, for example, a method of measuring the cutting angle of the front wheel at the time of full lock and comparing it with a set reference value in the vehicle can be considered. When the turning angle is deviated from the set reference value to some extent, a defect occurs in the wheel alignment, and the cutting angle is deviated. On the other hand, only by measuring the cutting angle at the time of full lock, even though it is understood that there is some cause that causes a shift in the cutting angle, it is not known what the cause is.

  Therefore, as a result of intensive studies on the cause of deviation in the cutting angle, the present inventor has found the following facts. It was found that the cause of the deviation of the turning angle was suspected of various factors such as the rack misalignment in the steering mechanism, the position misalignment of the side members and suspension members, and the knuckle arm bending. However, these causes cannot be distinguished only by measuring the cutting angle at the time of full lock.

  On the other hand, the present inventor has reached the following knowledge that distinguishes between the above-described factors caused by bending of the knuckle arm and the case caused by rack misalignment or the like. If there is a problem with wheel alignment due to rack misalignment, etc., the angle at full lock will deviate from the normal angle, while the angle at non-full lock will be affected. Is unlikely to occur. On the other hand, if there is a problem with wheel alignment due to the bending of the knuckle arm, it is easy to cause a deviation from the normal angle at both the full lock and non-full lock angles. is there.

Based on the above findings, the present inventor first reached the following reference technique. Based on the above knowledge, the inventor of the wheel alignment inspection method in the reference technology has reached the following invention. In the wheel alignment inspection method in the reference technology, the angle of the left front wheel measured in the state where the right front wheel is rotated in the first direction which is one of the left side and the right side so that the angle of cut is the first angle. Is the first turning angle, and the turning angle of the right front wheel measured in a state where the left front wheel is rotated in the second direction opposite to the first direction so that the turning angle is the first angle is the second turning angle. The cutting angle of the left front wheel measured in the state of rotating in the first direction so that the front wheel is fully locked is the third cutting angle, the cutting angle of the right front wheel is the fourth cutting angle, and the front wheel is When the cutting angle of the right front wheel measured in the second direction so as to be fully locked is the fifth cutting angle and the cutting angle of the left front wheel is the sixth cutting angle, the first cutting angle And the difference between the second cut angle and the first threshold, and the third cut angle and the fourth cut angle Based on both the difference (δ1), the difference (δ1−δ2) between the difference (δ2) between the fifth angle and the sixth angle, and the comparison with the second threshold value whose absolute value is larger than the first threshold value. To evaluate the cause of the wheel alignment failure.

  According to the reference technique, for example, the deviation state of the cutting angle at the time of full lock can be evaluated based on the third to sixth cutting angles measured at the time of full locking. Thereby, it can be test | inspected whether there exists a malfunction in wheel alignment. On the other hand, it may not be possible to distinguish whether the cause of the wheel alignment failure is due to the rack misalignment or the knuckle arm bend only based on the third to sixth cutting angles. For this reason, based on the 1st cut angle and the 2nd cut angle, the shift situation of the cut angle in the cut angle of the 1st angle smaller than full lock is further evaluated. For example, the deviation of the cutting angle at the time of full lock is somewhat large, but if the deviation of the cutting angle at the first angle is not so large, it can be evaluated that the cause is a rack position deviation or the like. Further, it can be evaluated that the knuckle arm is bent when the deviation of any of the cut angles is large to some extent even at the full lock and at the cut angle of the first angle. In this way, by considering both the deviation angle of the cutting angle at the time of full lock and the deviation angle of the cutting angle at the first angle, the knuckle arm is bent due to rack misalignment or the like. It is easy to distinguish the cause.

  And the wheel alignment inspection method in the present invention based on the above-mentioned reference technique is a state in which the left front wheel is rotated in the first direction which is one of the left side and the right side so that the turning angle becomes the first angle. Measured in a state where the cutting angle of the right front wheel to be measured is a first cutting angle and the right front wheel is rotated in a second direction opposite to the first direction so that the cutting angle becomes the first angle. The cutting angle of the right front wheel measured in a state where the cutting angle of the left front wheel is the second cutting angle and the left front wheel is rotated in the first direction so that the cutting angle is a second angle larger than the first angle. Is the third cutting angle, and the cutting angle of the left front wheel measured in a state where the right front wheel is rotated in the second direction so that the cutting angle is the second angle is the fourth cutting angle, A difference between the first cut angle and the second cut angle and a first threshold value; and Based on both the comparison of the 3 slices angle and the fourth slice angle and the difference between the absolute value than the first threshold value is larger second threshold value to evaluate the cause of trouble in the wheel alignment occurs.

  In the above reference technique, the shift angle deviation state at the time of full lock is evaluated, but in the present invention, the change in the shift angle deviation between the first angle and a second angle different from the first angle is evaluated. Check the wheel alignment. Based on the above knowledge that when the knuckle arm is bent, the larger the cutting angle, the larger the deviation of the cutting angle, and by evaluating the change of the deviation when changing the cutting angle, full lock As in the case based on the turning angle of time, it is possible to grasp whether or not the knuckle arm is bent.

  Further, in the present invention, the deviation from the reference angle at the cut angle of either the left front wheel or the right front wheel measured with the front wheel rotated in either the first direction or the second direction is derived. And a step of determining a defective state of the knuckle arm as the cause, wherein a deviation from the rotation direction of the front wheel and the reference angle in the derivation step is a deviation with respect to any of the left front wheel and the right front wheel. And determining whether the left or right knuckle arm is bent in the inner or outer direction based at least on whether the deviation from the reference angle is positive or negative. preferable. According to this, the defective state of the knuckle arm can be grasped in detail.

It is a schematic block diagram of the motor vehicle used as the test object of the wheel alignment test method according to one embodiment of the present invention. It is a flowchart which shows the flow of the test | inspection method of this wheel alignment. FIG. 3A is a schematic configuration diagram of the steering mechanism of the automobile in FIG. 1, FIG. 3A shows a case where the steering wheel is turned to the left, and FIG. 3B shows a case where the steering wheel is turned to the right. FIG. 4A is a schematic configuration diagram of the steering mechanism of the automobile in FIG. 1, FIG. 4A is a case where an inner curve is generated in the left knuckle arm, and FIG. 4B is an outer curve in the left knuckle arm. Show the case. It is a schematic block diagram of the steering mechanism of the motor vehicle of FIG. 1, Comprising: The case where the position shift has arisen in the rack is shown.

  A wheel alignment inspection method (hereinafter referred to as the present inspection method) according to a reference embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of an automobile 1 that is an object of this inspection method. The automobile 1 has front wheels 2L (left front wheels) and 2R (right front wheels), rear wheels 3L and 3R, and a steering mechanism 10. The steering mechanism 10 includes a handle 20, a rack 11, tie rods 12L and 12R, and knuckle arms 13L and 13R. When the driver operates the handle 20, the rotation of the handle 20 is transmitted to the rack 11 via a pinion gear (not shown), and the rack 11 moves in the left-right direction. The movement of the rack 11 is transmitted to the knuckle arms 13L and 13R through the tie rods 12L and 12R, and the knuckle arms 13L and 13R rotate. As a result, the front wheels 2L and 2R rotate (see FIGS. 3A and 3B). The vehicle 1 is provided with various configurations for the driver to drive the vehicle 1, such as an engine, a transmission mechanism that transmits the driving force of the engine to the rear wheels 3 </ b> L and 3 </ b> R, and an operation unit other than the handle 20.

  Hereinafter, the term “full lock” refers to a state in which the handle 20 is cut to the left or right as much as possible, or is in a cut state. The outer front wheel or the inner front wheel means a front wheel that is disposed on the outer side or the inner side in the turning motion of the automobile 1 that occurs when the steering wheel 20 is turned to the left or right while the automobile 1 is running, among the front wheels 2L and 2R. Shall. The cutting angle of the front wheel means the rotation angle of the front wheel based on the straight traveling state shown in FIG. For example, the cutting angle of the front wheel indicates an angle indicated by α or β in FIG. 3 (a) or FIG. 3 (b). In FIG. 3 (a), α indicates the turning angle of the outer front wheel (front wheel 2R) when the front wheel is turned to the left. [Beta] in FIG. 3 (a) indicates the turning angle of the inner front wheel (front wheel 2L) when the front wheel is turned to the left. In FIG. 3 (b), α indicates the cutting angle of the outer front wheel (front wheel 2L) when the front wheel is cut to the right. Β in FIG. 3 (b) indicates the turning angle of the inner front wheel (front wheel 2R) when the front wheel is cut to the right. In the following, αn represents the turning angle of the inner front wheel, and βn represents the turning angle of the outer front wheel.

  In this inspection method, first, as shown in S1 of FIG. The pre-adjustment includes a step of installing the automobile 1 in the alignment tester device and a step of adjusting the toe of the rear wheels 3L and 3R so that the thrust line of the automobile 1 coincides with the geometric center line. Further, in this inspection method, it is assumed that the front wheels 2L and 2R take the straight traveling state shown in FIG. 1 when the handle 20 is in the center. For this reason, when the front wheels 2L and 2R do not take a straight traveling state when the handle 20 is at the center before the main inspection, the front wheels 2L and 2R take a straight traveling state when the handle 20 is at the center in the pre-adjustment. Thus, the lengths of the tie rods 12L and 12R may be adjusted.

  The alignment tester device (hereinafter referred to as “tester”) used in the present embodiment has the respective cutting angles of the front wheels 2L and 2R when the handle 20 is fully locked and the cutting angle of the outer front wheel is 20 °. Can be measured. The state where the cutting angle of the outer front wheel is 20 ° refers to a state where the cutting angle of the outer front wheel is 20 ° (the first angle in the reference technique). Note that the alignment tester device may be capable of measuring the respective turning angles of the front wheels 2L and 2R when the handle 20 is in a state where the turning angle of the inner front wheel is 20 °. In this case, the cutting angle of the front wheel 2L or 2R when the handle 20 is in the state of 20 ° of the outer front wheel in the following is replaced with the cutting angle of when the handle 20 is in the state of 20 ° of the inner front wheel. May be.

  Next, each of the outer front wheel (front wheel 2R) and the inner front wheel (front wheel 2L) in a state where the handle 20 is turned to the left (first direction in the reference technology) so that the turning angle of the outer front wheel is 20 °. The angle is measured by a tester (S2). Then, a difference β1-α0 between the inner front wheel turning angle β1 (first cutting angle in the reference technique) and the outer front wheel turning angle α0 (= 20 °) is calculated (S3). Next, each of the outer front wheel (front wheel 2L) and the inner front wheel (front wheel 2R) in a state where the handle 20 is turned to the right (second direction in the reference technology) so that the turning angle of the outer front wheel is 20 °. The angle is measured by a tester (S4). Then, a difference β2−α0 between the inner front wheel turning angle β2 (second cutting angle in the reference technology) and the outer front wheel turning angle α0 (= 20 °) is calculated (S5).

  Next, each angle of the outer front wheel (front wheel 2R) and the inner front wheel (front wheel 2L) in a state where the handle 20 is turned to the left so as to be fully locked is measured by a tester (S6). Then, a difference β3-α1 (= δ1) between the inner front wheel turning angle β3 (third cutting angle in the reference technique) and the outer front wheel cutting angle α1 (fourth cutting angle in the reference technique) is calculated (S7). ). Next, the angle of each of the outer front wheel (front wheel 2L) and the inner front wheel (front wheel 2R) in a state where the handle 20 is turned to the right so as to be fully locked is measured by a tester (S8). Then, a difference β4-α2 (= δ2) between the inner front wheel cutting angle β4 (fifth cutting angle in the reference technique) and the outer front wheel cutting angle α2 (sixth cutting angle in the reference technique) is calculated (S9). ).

  Next, based on the values measured and calculated in S1 to S9, it is determined whether or not there is a defect in the wheel alignment, and if there is a problem, the cause is determined (S10).

  The determination method of S10 will be described in detail. For this determination, the absolute value of the left / right difference Δ1 of the inside / outside difference relating to the turning angle measured with the turning angle of the outer front wheel being 20 ° and the left / right difference Δ2 of the inside / outside difference relating to the turning angle measured in the full lock state are calculated. Use absolute values. The inside / outside difference means the difference between the measured value at the inner front wheel and the measured value at the outer front wheel. The left / right difference means a difference between a value when the handle 20 is turned to the left and a value when the handle 20 is turned to the right. That is, the absolute value | Δ1 | = | β1−β2 | of the difference between the calculation result of S3 and the calculation result of S5, and the absolute value | Δ2 | = | α1− of the difference between the calculation result of S7 and the calculation result of S9. α2-β3 + β4 | is used. When | Δ2 | is less than 1 ° (second threshold in the reference technique), the wheel alignment is determined to be a normal range, and when | Δ2 | is 1 ° or more, the wheel alignment is not within a normal range (wheel It is determined that the alignment is defective. And when it determines with the range where wheel alignment is not normal, the cause is further determined as follows.

  First, it is determined whether or not | Δ1 | is 30 ′ (first threshold value in the reference technique) or more. If | Δ1 | is less than 30 ′, it is determined that the cause of the wheel alignment failure is other than the knuckle arms 13L and 13R. For example, the cause is considered to be in any position other than the knuckle arms 13L and 13R, such as the position shift of the rack 11, the position shift of the side member, and the suspension member. On the other hand, when | Δ1 | is 30 ′ or more, that is, when | Δ1 | ≧ 30 ′ and | Δ2 | ≧ 1 °, it is determined that there is a high probability that the knuckle arm 13L or 13R is bent.

  Therefore, if | Δ1 | ≧ 30 ′ and | Δ2 | ≧ 1 °, then based on at least one of α1, α2, β3, and β4 acquired in S6 and S8, the knuckle arm 13L and The defective state of 13R is determined as shown in Table 1. In addition, when the front wheel turning angle is shifted due to a defect in the knuckle arm 13L or 13R, uneven wear tends to occur in the tire. Therefore, uneven wear of the tire is determined as shown in Table 1 according to the values of α1, α2, β3, and β4.

  Li and Lo in the first row of Table 1 are the reference value of the turning angle of the inner front wheel (front wheel 2L) and the outer front wheel (front wheel 2R) of the vehicle when the handle 20 is turned to the left so as to be fully locked. This is the reference value for the angle of cut. Ri and Ro are reference values for the turning angle of the inner front wheel (front wheel 2R) of the vehicle and the reference value of the turning angle of the outer front wheel (front wheel 2L) when the steering wheel 20 is turned to the right so as to be fully locked. is there. Such a reference value is provided by the manufacturer of the automobile 1 as a set value at the time of manufacture, for example.

  The first column of Table 1 shows the conditions related to the state of deviation of the turning angle during full lock. For example, the condition “β4-Ri ≧ 2 °” is that “the deviation from the reference value in the turning angle of the inner front wheel (front wheel 2R) when the handle 20 is turned to the right until the front wheel is fully locked is correct. , Specifically, it is 2 ° or more ”. Further, the condition “α1-Lo ≦ −2 °” is that “the deviation from the reference value in the turning angle of the outer front wheel (front wheel 2R) when the handle 20 is turned to the left until the front wheel is fully locked”. This corresponds to the condition of “negative, specifically −2 ° or less”. As described above, the conditions in the first column of Table 1 are whether the rotation direction of the front wheel when measuring the deviation of the turning angle is right or left, and whether the measured deviation is a deviation relating to which of the front wheels 2L and 2R. It is related to whether the deviation is positive or negative and whether the magnitude of the deviation is a certain level or more.

  The second column of Table 1 indicates whether the knuckle arm 13L (left) or 13R (right) is defective (bent). The third row shows whether the inward or outward bending occurs in the defective knuckle arm. FIG. 4A is an example of a case where the knuckle arm 13L is bent inward. The rear part of the knuckle arm 13L is bent inward (rightward in the figure). FIG. 4B is an example of a case where the outward bending is generated in the knuckle arm 13L. The rear part of the knuckle arm 13L is bent outward (leftward in the figure). As shown in these figures, when the knuckle arm 13L is bent, the length of the tie rod 12L is adjusted so that the front wheels 2L and 2R are correctly directed straight when the handle 20 is in the center. The As a result, the length of at least one of the tie rods 12L and 12R in FIG. 4 does not match the length in FIG. The same applies to the case where the knuckle arm 13R is bent. In this case, the relationship between the inside and outside and the left and right is reversed from the case of the knuckle arm 13L. The fourth and fifth rows in Table 1 indicate which of the left and right tires is likely to have uneven wear on the inner side and the outer side. Table 2 shows the contents of each variable.

  An example of the determination based on Table 1 is as follows. When the difference β4-Ri obtained by subtracting the reference angle from the cut angle of the inner front wheel (front wheel 2R) measured when the front wheel is rotated to the right to the full lock is negative and −2 ° or less There is a high probability that the knuckle arm 13R on the right side is bent outward. In this case, knitting wear tends to occur outside the right tire. Also, when the difference α2−Ro obtained by subtracting the reference angle from the cut angle of the left (outer) front wheel measured when the front wheel is rotated to the right to the full lock is 2 ° or more There is a high probability that the knuckle arm 13L on the left side is bent outward. In this case, knitting wear tends to occur outside the right tire.

  The reason why the cause of the wheel alignment defect can be determined as described above will be described. This determination is based on the knowledge on the right: If there is a problem with the wheel alignment due to the misalignment of the rack 11 or the like, the turning angle at the time of full lock is likely to be shifted, while that at the time of not being full lock Deviations in the cutting angle are unlikely to occur. On the other hand, when the wheel alignment has a defect due to the bending of the knuckle arm 13L or 13R, the cutting angle is likely to be generated at both the full lock and the full lock.

  For example, it is assumed that the rack 11 is displaced in the left-right direction due to the displacement of the installation position of the rack 11 with respect to the vehicle body. In this case, as described above, the lengths of the tie rods 12L and 12R are adjusted such that when the handle 20 is at the center, the front wheels are correctly oriented in the straight traveling direction. FIG. 5 shows, as an example, when the rack 11 is shifted to the right, by adjusting the lengths of the tie rods 12L and 12R, the knuckle arms 2L and 2R, the left front wheel 2L, and the right front wheel 2R are directed straightly. Indicates the state. When the handle 20 is turned to the left or right from this state, the knuckle arms 13L and 13R rotate through the tie rods 12L and 12R according to the movement of the rack 11. When there is no abnormality in the knuckle arms 12L and 12R, the knuckle arms 12L and 12R rotate almost normally as the rack 11 moves. For this reason, for example, when the front wheel is at any turning angle until it is close to full lock, the front wheel turning angle is unlikely to deviate from the normal angle. However, if the handle 20 is rotated until the front wheels are fully locked, the initial position of the rack 11 is shifted, so that the position of the rack 11 when fully locked is also shifted from the normal position. . Therefore, when the front wheel is near full lock, the turning angle tends to deviate from the normal angle.

  On the other hand, when the knuckle arm 13L or 13R is bent as shown in FIG. 4, the amount of rotation of the knuckle arm 13L or 13R with respect to the movement of the rack 11 by a predetermined amount (the amount of change in the rotation angle) Deviation from the rotation amount when the knuckle arm is normal occurs. The deviation of the rotation amount occurs from the beginning of turning the handle 20, and becomes larger as the front wheel approaches the full lock state. Therefore, when the knuckle arm 13L or 13R is bent, the deviation from the normal knuckle arm at the turning angle of the front wheel 2L or 2R starts until the front wheel becomes fully locked after the handle 20 starts to be cut. The cut angle in the middle of, for example, a 20 ° cut angle is also somewhat large. The deviation increases as the front wheel turning angle increases.

  Further, when the knuckle arm 13L or 13R is bent, as described above, the deviation of the turning angle is large even when the front wheel is at a turning angle before reaching the full lock. Therefore, when the front wheel 2L or 2R is deviated from the normal turning angle, the load applied to the tire of the front wheel when the automobile 1 travels on a curve is likely to deviate inward or outward as compared with the normal case. For this reason, the tire tends to cause uneven wear (so-called internal decrease) on the inside or uneven wear (so-called external decrease) on the outside.

  According to the reference form described above, it is possible to evaluate the deviation state of the turning angle when the turning angle of the outer front wheel is 20 ° by calculating | Δ1 |, and to evaluate the deviation state of the turning angle at the time of full lock by calculating | Δ2 |. it can. For example, the deviation state of the turning angle at the time of full lock is evaluated by whether or not | Δ2 | ≧ 1 ° is satisfied. Thereby, it is possible to evaluate whether or not the wheel alignment is defective. On the other hand, there is a possibility that it is impossible to distinguish whether the cause of the wheel alignment failure is due to the displacement of the rack 11 or the bending of the knuckle arm 13L or 13R only by the evaluation based on | Δ2 |. Therefore, not only whether or not | Δ2 | ≧ 1 ° is satisfied, but also whether the angle of deviation of the outer front wheel is 20 ° or not is further evaluated depending on whether or not | Δ1 | ≧ 30 ′ is satisfied. Thereby, the high probability that the knuckle arm 13L or 13R is bent is evaluated. That is, by evaluating both Δ1 and Δ2, it is possible to distinguish whether the cause is a rack misalignment or the like or a knuckle arm bend.

  Furthermore, based on the conditions in Table 1, that is, the rotational direction of the front wheels, the measured deviation is related to which of the front wheels 2L and 2R, and whether the deviation is positive or negative, the knuckle arm 13L And 13R to evaluate what kind of bending occurs. Therefore, the defective state of the knuckle arm 13L or 13R can be determined in detail.

  Hereinafter, modifications of the above-described reference embodiment will be described. In the above-described reference mode, the deviation state of the turning angle in the state where the turning angle of the outer front wheel is 20 ° and the state at the time of full lock depend on whether or not | Δ1 | ≧ 30 ′ is satisfied and whether or not | Δ2 | ≧ 1 ° is satisfied. Evaluates the deviation of the cutting angle. However, the evaluation of the state of deviation of the turning angle may be performed based on other conditions. For example, a numerical value other than 30 ′ or 1 ° may be used. Moreover, you may evaluate by (alpha) 1, (alpha) 2, (beta) 1- (beta) 4 satisfy | filling predetermined conditions, without using (DELTA) 1 and (DELTA) 2. As an example, the deviation state of the cutting angle may be evaluated as a deviation from the reference value by comparing α1 and β2 with the reference values relating to each. In short, any method that can evaluate how much deviation occurs in the turning angle of the outer front wheel when the turning angle is 20 ° and how much deviation occurs in the turning angle during full lock, Such a method may be adopted.

  Moreover, in the above-mentioned reference form, the cutting angle of the inner front wheel in the state where the cutting angle of the outer front wheel is 20 ° is measured as α1 and α2. However, the cutting angle of the outer front wheel in a state where the cutting angle of the inner front wheel is 20 ° may be measured. Further, the cut angle may not be 20 ° but may be other angles smaller than the angle at the time of full lock.

  In the above-described reference embodiment, the cause of the wheel alignment failure is based on the front wheel cut angle measured in the state of the outer front wheel cut angle of 20 ° and the front wheel cut angle measured in the full lock state. Is judged. However, the cutting angle of each front wheel measured in the state of the cutting angle of each front wheel and the cutting angle θ2 of the outer front wheel (θ2> θ1) measured with the cutting angle θ1 of the outer front wheel (θ1 <angle at full lock). The cause of the wheel alignment defect may be determined based on the angle.

  Therefore, in the embodiment according to the present invention based on the above reference form, the turning angle of the right front wheel measured in a state where the left front wheel is rotated rightward (first direction) up to the turning angle θ1 (first angle). A difference Δa between the (first cutting angle) and the cutting angle (second cutting angle) of the left front wheel measured in a state where the right front wheel is rotated leftward (second direction) up to the cutting angle θ1 is calculated. Also, the right front wheel turning angle (third cutting angle) measured with the left front wheel rotated rightward to the turning angle θ2 (second angle), and the right front wheel rotated leftward to the cutting angle θ2. A difference Δb from the left front wheel turning angle (fourth turning angle) measured in the above state is calculated. θ2 is larger than θ1. When the absolute value of Δa is larger than the first threshold and the absolute value of Δb is larger than the second threshold larger than the first threshold, it is determined that there is a high probability that the knuckle arm 13L or 13R is bent. To do. Thus, it may be determined that the knuckle arm 13L or 13R is bent by evaluating the change in the deviation of the cutting angle when the cutting angle changes. Further, in the same manner as in the above reference embodiment based on Table 1, based on how the front wheel turning angle is deviated from the reference angle, what kind of bending occurs in the knuckle arms 13L and 13R. It is also possible to grasp in more detail.

  Also in this embodiment, the evaluation may be performed by directly determining whether or not the measured value of the cutting angle satisfies a predetermined condition without using Δa and Δb. As an example, by comparing the cutting angle of the left front wheel measured with the right front wheel rotated to the left to the cutting angle θ1 with the reference value, it is possible to determine how much the cutting angle is deviated from the reference value. You may evaluate as. In short, any method can be used to evaluate how much deviation occurs in the turning angle of the outer front wheel at the turning angle θ1 and how much deviation occurs in the turning angle of the outer front wheel at the turning angle θ2. Any method may be adopted.

2L, 2R Front wheel 3L, 3R Rear wheel 10 Steering mechanism 11 Rack 12L, 12R Tie rod 13L, 13R Knuckle arm

Claims (2)

The cutting angle of the right front wheel measured in a state where the left front wheel is rotated in the first direction which is one of the left side and the right side so that the cutting angle becomes the first angle is defined as the first cutting angle.
The left front wheel cut angle measured in a state in which the right front wheel is rotated in a second direction opposite to the first direction so that the cut angle is the first angle is defined as a second cut angle,
The angle of the right front wheel measured in a state where the angle of the left front wheel is rotated in the first direction so that the angle of turn is a second angle larger than the first angle is defined as a third angle of cut.
When the cutting angle of the left front wheel measured in a state where the cutting angle of the right front wheel is rotated in the second direction so that the cutting angle becomes the second angle is set as the fourth cutting angle,
The difference between the first cut angle and the second cut angle and a first threshold value, and the difference between the third cut angle and the fourth cut angle and a second absolute value greater than the first threshold value. A wheel alignment inspection method characterized by evaluating a cause of a defect in wheel alignment based on both comparison with a threshold value. A derivation step of deriving a deviation from a reference angle in either the left front wheel or the right front wheel measured in a state where the front wheel is rotated in either the first direction or the second direction;
A step of determining a defective state of the knuckle arm as the cause,
In the derivation step,
Direction of rotation of the front wheels,
Whether the deviation from the reference angle is a deviation of the left front wheel or the right front wheel, and
And determining whether the left or right knuckle arm is bent in either the inner or the outer direction based on at least whether the deviation from the reference angle is positive or negative. Item 2. The wheel alignment inspection method according to Item 1.

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