JP2005007418A - Welding torch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding torch capable of simplifying welding equipment and enhancing the production efficiency of a wheel. <P>SOLUTION: The wheel 18 is formed by welding a joining part 26 of a press-fit part with a wheel disk 16 inserted in a wheel rim 14 by a welding torch 10 fitted to a head part 34b supported by an arm 34a of a robot 34. The head part 34b is rotatable with respect to the arm 34a (in the direction of an arrow A). The welding torch 10 has a holding means 102 to take out the joining-completed wheel 18 from a loading part 40. The holding means 102 extends in the direction across the axis B of rotation of the head part 34b of the robot 34, for example, the orthogonal direction (the direction of an arrow C). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a welding torch for joining a wheel rim formed from a plate-shaped material and a wheel disk.
[0002]
[Prior art]
Conventionally, as a tire wheel of an automobile or the like (hereinafter simply referred to as a wheel), a rim formed in a cylindrical shape from a plate-shaped material and a disk formed in a disk shape are combined and welded. Joined two-piece wheels are widely used.
[0003]
An example of this type of two-piece wheel is the wheel 1 shown in FIG. The wheel 1 includes a rim 2 formed by roll-forming a steel or a light alloy wrought material, and a disc 3 formed by press-molding the same type of wrought material as the rim 2, and is integrally assembled by arc welding. At the time of joining by arc welding, the wheel 1 is inclined at a predetermined angle (in this case, 30 ° with respect to the horizontal direction), and the aim of the welding torch 5 is moved to the disk 3 side by about the diameter of the welding wire 6. (W dimension in FIG. 11) Further, by adjusting the welding current, voltage, and moving speed of the welding torch 5 according to the plate thickness of the rim 2 and the disk 3, the weld penetration 7 is reduced to about the plate thickness of the rim 2. It is made to form in 10 to 30% (for example, refer patent document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-58103 (paragraph [0009], FIGS. 2 and 3)
[0005]
[Problems to be solved by the invention]
By the way, the wheel 1 integrally assembled by arc welding needs to be taken out of, for example, a rotary table of a welding machine and transported to a subsequent process such as an inspection process.
[0006]
The present invention has been made in connection with the above-described take-out and conveyance, and includes a gripping means for taking out the wheel, simplifying the apparatus, and improving the production efficiency of the wheel. The purpose is to provide.
[0007]
[Means for Solving the Problems]
A welding torch according to the present invention is a welding torch attached to a welding robot that joins a wheel rim formed from a plate-shaped material and a wheel disk to form a wheel, and the welding torch includes the welding robot. The welding torch is provided with gripping means for taking out the wheel, and the gripping means intersects the rotation axis of the head part of the welding robot. It is characterized by extending in the direction.
[0008]
According to the welding torch according to the present invention, since the welding torch is provided with the gripping means for taking out the wheel, the welding robot to which the welding torch is attached can be shared. As a result, it is possible to simplify the welding robot and to save space in the welding system in which the welding robot is installed.
[0009]
In addition, since the gripping means extends in a direction intersecting the rotation axis of the head portion of the welding robot, mutual interference between the welding torch joining operation and the gripping means take-out operation is prevented. Can do. As a result, since the interruption of the welding system due to such mutual interference is avoided, the production efficiency of the wheel can be improved.
[0010]
In this case, the gripping means includes a clamp portion that grips the wheel via a bolt hole or a hub hole of the wheel. As a result, there is no need to rely on manual work when removing the wheel, and there is no need to provide other auxiliary members or tools, etc., making it possible to further simplify the welding robot and to produce the wheel. Efficiency can be further improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of a welding torch according to the present invention will be given and described in detail below with reference to the accompanying drawings.
[0012]
FIG. 1 is a schematic perspective explanatory view of a welding system 12 to which a welding torch 10 according to the present embodiment is applied. FIG. 2 is a diagram in which a wheel rim 14 and a wheel disk 16 are joined by welding using the welding torch 10. FIG. 5 is a longitudinal sectional view of the wheel 18 formed integrally.
[0013]
First, the wheel 18 will be described with reference to FIG. The wheel 18 is made of a plate-shaped material, for example, a light alloy material such as an aluminum alloy, a steel material, or the like, and is formed into a cylindrical shape by forming the material by a press method or a forging method, A wheel disk 16 formed in a disk shape.
[0014]
The wheel rim 14 is formed in a flange portion 14a in which peripheral portions on both sides thereof are erected, a bead seat portion 14b in which a bead portion of a tire (not shown) is fitted inside the flange portion 14a, and a bead seat portion 14b. The hump portion 14c and the well portion 14d recessed toward the central axis P of the wheel 18 are provided. An air valve hole 14e in which an air valve (not shown) is mounted is provided on the side of the well portion 14d on the wheel disk 16 side.
[0015]
On the other hand, the wheel disc 16 has a hub hole 20 for fixing to a hub (not shown), and a plurality of bolt holes 22 arranged at equal intervals along the circumferential direction of the wheel disc 16 outside the hub hole 20. Have. A hub bolt (not shown) for fastening the wheel disc 16 to the hub is inserted into the bolt hole 22 by cooperation with a nut (not shown). A peripheral edge portion 22a is formed around the bolt hole 22 so as to protrude toward the fastening surface side of the hub.
[0016]
Further, the wheel disc 16 has a plurality of decorative holes 24 arranged at equal intervals along the circumferential direction of the wheel disc 16 inside the peripheral edge portion 16a. The decorative hole 24 has a decorative property from the viewpoint of design, and also has a function of releasing frictional heat generated from a brake drum (not shown) or a brake disk adjacent to the hub.
[0017]
As easily understood from FIG. 2, the peripheral edge portion 16a of the wheel disk 16 is inserted into the inner side surface of the well portion 14d of the wheel rim 14 by, for example, press-fitting, and is joined by welding (MIG welding or the like). To form the wheel 18.
[0018]
Next, the welding system 12 to which the welding torch 10 is applied will be described.
[0019]
As shown in FIG. 1, the welding system 12 is positioned and placed after a press-fit product 30 in which a wheel disk 16 is inserted into a wheel rim 14 is supplied via, for example, a supply conveyor (not shown). In addition, it is formed by placing / tilting means 32 for inclining the press-fitted product 30, an articulated robot (welding robot) 34 to which the welding torch 10 is attached, and welding using the welding torch 10. The wheel 18 has a conveyer 36 made of a belt conveyer or the like for conveying the wheel 18 to a subsequent process such as an inspection process.
[0020]
As shown in FIGS. 3 and 4, the placing / tilting means 32 includes a placing portion 40 that supports the press-fitted product 30 (wheel 18) via a support block 38, and a base portion on which the placing portion 40 is mounted. 41.
[0021]
As shown in FIGS. 5 to 7, when the press-fit product 30 is placed on the support block 38, the placement part 40 is guided through the hub hole 20 of the wheel disk 16, and the press-fit product 30 has a diameter. An insertion block 42 for positioning in the direction and a positioning pin 44 for positioning the press-fit product 30 in the circumferential direction on the support block 38 through the bolt holes 22 of the wheel disk 16 are provided.
[0022]
A plurality of support blocks 38 are arranged in the circumferential direction corresponding to each of the bolt holes 22. In addition, escape holes 38a are formed in the two support blocks 38 disposed to face each other in the radial direction so as to correspond to clamp portions 104 of the gripping means 102 described later. Further, in the vicinity of the support block 38, a detection shaft 45 having a contact portion 45a for determining whether or not the press-fit product 30 has contacted the support block 38, and a contact portion 45a of the detection shaft 45, On the opposite side, a shaft detector (not shown) for detecting a position-adjustable detected member is provided.
[0023]
The insertion block 42 is formed in a tapered shape that is reduced in diameter upward. The insertion block 42 is formed with a slit 42a penetrating in the radial direction. The slit 42a has a pair of clamps 46 and 48 for fixing or releasing the press-fit product 30 by opening and closing each other. It is arranged. The tips of the clamps 46 and 48 are formed in a substantially claw shape.
[0024]
The clamps 46 and 48 are formed with bent long hole-shaped guided holes 46a and 48a, respectively, and the guide shaft 50 fixed to the lower side of the support block 38 in the guided holes 46a and 48a. Is inserted. The clamps 46 and 48 are rotatably connected to one end 53 a of a rod 53 of a cylinder 52 formed of an air cylinder or the like via a connecting pin 54, and are advanced and retracted by urging the cylinder 52. That is, the clamps 46 and 48 are moved back and forth and opened and closed by the forward / backward action of the cylinder 52 and the guide action of the guide shaft 50 with respect to the guided holes 46a and 48a.
[0025]
The other end 53b of the rod 53 of the cylinder 52 is provided with a detected member 53c whose position can be adjusted. A pair of rod detectors 56 a and 56 b including a proximity sensor that adjusts the stroke of the forward and backward movement of the cylinder 52 by detecting the detected member 53 c is provided in the vicinity of the other end 53 b of the rod 53. In other words, by adjusting the positional relationship of the rod detectors 56a and 56b with respect to the rod 53 of the cylinder 52, it is possible to cope with the type change due to the plate thickness of the wheel disc 16 of the press-fit product 30 or the like. By comprising in this way, it becomes possible to perform the said kind change efficiently.
[0026]
A work detector (not shown) made up of a transmission type sensor for detecting the presence or absence of the press-fit product 30 is provided in the vicinity of the mounting portion 40.
[0027]
As shown in FIGS. 3 and 4, the base 41 includes a housing 70 and a rotary table 72 that is rotatably supported by the housing 70. A motor (not shown) such as a servo motor is provided inside the housing 70, and the rotary table 72 is rotated by the rotation bias of the motor. The mounting unit 40 is mounted on the rotary table 72. Accordingly, the press-fit product 30 mounted on the mounting unit 40 is rotated by the rotation bias of the motor. In addition, in the vicinity of the turntable 72 on the housing 70, positioning means (not shown) having a knock pin or the like is provided in order to position the turntable 72 in the rotation direction.
[0028]
Further, the mounting / tilting means 32 includes an inclined portion 80 that tilts the mounting portion 40 together with the base portion 41 by turning. The inclined portion 80 includes a support shaft 84 that rotatably supports the base portion 41 via a bracket 82, and a cylinder 86 that includes a hydraulic cylinder that rotates the base portion 41 together with the bracket 82 with the support shaft 84 serving as an axis. Is provided. The bracket 82 is rotatably connected to one end 88 a of the rod 88 of the cylinder 86 via a connecting member 90.
[0029]
Further, the support shaft 84 is fixed to the main frame 92 of the inclined portion 80. Accordingly, the press-fit product 30 placed on the placement unit 40 is swung upward, that is, inclined upward, by the advance operation (in the direction of the arrow X1) of the rod 88 that is advanced and retracted by the urging of the cylinder 86. Will be. In this case, the inclination angle θ with respect to the horizontal direction is preferably 30 ° to 60 °, and is preferably about 45 ° (see FIG. 4).
[0030]
The inclined portion 80 includes a spring for positioning the bracket 82 at a predetermined inclined position as well as absorbing an impact caused by the contact portion 82a of the bracket 82 contacting when the bracket 82 rotates. When the upper stopper 94a and the inclined bracket 82 return to the normal position (horizontal position), the impact due to the contact portion 82b of the bracket 82 coming into contact is absorbed and the bracket 82 is positioned at a predetermined horizontal position. And a lower stopper 94b including a spring or the like. These stoppers 94 a and 94 b are fixed to the main frame 92. In addition, the cylinder 86 is rotatably supported by a support member 96 in order to follow the arcuate locus of the bracket 82 that rotates as the rod 88 advances and retreats.
[0031]
As shown in FIGS. 8 to 10, the welding torch 10 has a bracket 100, and is attached to the head portion 34 b supported by the final stage arm 34 a of the robot 34 via the bracket 100. The head portion 34b is rotatable with respect to the arm 34a (in the direction of arrow A in FIG. 8). Therefore, the welding torch 10 is rotatably supported by the head portion 34b. The bracket 100 is provided with a gripping means 102 for taking out the wheel 18 that has been joined by the welding torch 10 from the mounting portion 40 described above. The gripping means 102 extends in a direction intersecting with the rotation axis B of the head portion 34b of the robot 34, for example, a direction orthogonal to the direction (arrow C direction in FIG. 8).
[0032]
The gripping means 102 includes a plurality of (for example, two) clamp portions 104 that grip the wheel 18 by being inserted into the bolt holes 22 of the wheel 18. The clamp unit 104 is attached to one end of a cylinder 108 formed of an air cylinder or the like that is connected to the pedestal unit 106. A slit 104a is formed in the clamp portion 104, and a pair of claw-like members that grip or release the bolt hole 22 from the inside by expanding or contracting the interval by the forward / backward movement of the cylinder 108. 105a and 105b are provided.
[0033]
The pedestal portion 106 is provided with an adjustment portion 110 for adjusting the gripping force of the claw-like members 105a and 105b of the clamp portion 104 against the bolt hole 22 of the wheel 18. The adjusting unit 110 includes a position-adjustable detected member 110a provided on the other end side of the rod 108a of the cylinder 108, and a pair of rod detectors 110b including a proximity sensor that detects the detected member 110a. .
[0034]
Here, the gripping force with respect to the bolt hole 22 is adjusted by the stroke of the forward and backward movement of the rod 108a by the urging of the cylinder 108. That is, the clamp portion 104 is provided with a mechanism (not shown) that can adjust the amount of expansion and contraction of the claw-like members 105a and 105b as the rod 108a moves forward and backward. When the position of the detected member 110a on the side, particularly the position of the forward movement of the rod 108a (in the direction of arrow C1 in FIG. 10) is adjusted, the stop position in the forward movement of the rod 108a is determined. Thereby, the stroke of the rod 108a is adjusted, and the gripping force with respect to the bolt hole 22 is adjusted. Thus, by providing the adjustment part 110, it becomes possible to respond also to the kind change by the plate | board thickness etc. of the wheel disc 16. FIG.
[0035]
In addition, the pedestal portion 106 is provided with a detection portion 112 for detecting that the clamp portion 104 has come into contact with the wheel 18. The detection unit 112 includes a detection shaft 112b having a contact portion 112a at one end, a position-adjustable detection member 112c provided at the other end of the detection shaft 112b, a proximity sensor that detects the detection member 112c, and the like. The detector 114 which consists of these. Thus, by providing the detection unit 112, it is possible to reliably detect that the clamp unit 104 is in contact with the wheel 18 and inserted into the bolt hole 22.
[0036]
The welding system 12 includes a control unit (not shown) that controls the welding system 12 in an integrated manner.
[0037]
Next, the operation of the welding system 12 and the joining work for the press-fit product 30 will be described.
[0038]
When the press-fitted product 30 is placed on the support block 38 of the placing portion 40 by the guiding action by the fitting insertion block 42 and the positioning action by the fitting insertion block 42 and the positioning pin 44, the workpiece detector and shaft A detection signal is output from the detector to the control unit. In response to these detection signals, an operation command is output from the control unit to each component of the welding system 12, and the operation of the welding system 12 is started.
[0039]
First, the clamps 46 and 48 are opened by the retraction operation of the rod 53 by the urging force of the cylinder 52 (in the direction of arrow Z1 in FIG. 7) and the guide action of the guide shaft 50 with respect to the guided holes 46a and 48a. The press-fit product 30 placed on the portion 40 is fixed to the support block 38.
[0040]
Next, the bracket 82 is pivoted by the forward movement of the rod 88 by the urging of the cylinder 86 (in the direction of arrow X1 in FIGS. 3 and 4). With this turning operation, the press-fit product 30 placed on the placement unit 40 turns upward, and the bracket 82 comes into contact with the upper stopper 94a, whereby the press-fit product 30 is held at the inclination angle θ. . In this case, the inclination angle θ is preferably set to 45 °.
[0041]
Next, the welding torch 10 is moved toward the press-fit product 30 held at the inclination angle θ by the operation of the robot 34. In addition, the front-end | tip part of the welding torch 10 is moved toward from the substantially perpendicular direction toward the junction part 26 of the wheel rim 14 and the wheel disc 16 (arrow Z1 direction in FIG. 9).
[0042]
Therefore, after the rotation prevention of the rotary table 72 by the positioning means is released, the press-fit product 30 held at the inclination angle θ is rotated by the rotation bias of the motor provided in the base 41. Along with the operation, it is rotated together with the mounting portion 40 (see FIGS. 3 and 4). At the same time, a welding rod or a welding wire (not shown) is supplied to the joining portion 26, and an operation command according to welding conditions set in the control unit, for example, a welding current supplied to the welding torch 10 and the motor Based on a command such as a rotational speed, welding to the joint portion 26 is performed. Thereby, the wheel 18 is obtained from the press-fit product 30 (see FIG. 9).
[0043]
When the welding to the joint portion 26 is completed, the rotation urging of the motor is stopped, and the rotation of the wheel 18 together with the mounting portion 40 is stopped. At the same time, the positioning means is operated to position the rotary table 72 at a predetermined position in the rotational direction. Next, by the operation of the robot 34, the welding torch 10 is moved away from the joining portion 26 in the direction opposite to the above (in the direction of arrow Z2 in FIG. 9). Thereafter, the gripping means 102 is moved toward the wheel disk 16 of the wheel 18 and the clamp portion 104 of the gripping means 102 is inserted into the bolt hole 22 of the wheel disk 16 (in the direction of arrow C1 in FIG. 10).
[0044]
Here, the detection unit 112 detects whether or not the clamp unit 104 is in contact with the wheel 18 and inserted into the bolt hole 22. That is, when the contact portion 112a of the detection shaft 112b of the detection unit 112 contacts the wheel disk 16 and the detector 114 detects the detected member 112c, the approaching movement of the gripping means 102 is stopped. Therefore, the claw-like members 105a and 105b of the clamp portion 104 are expanded in diameter by the advance operation of the rod 108a by the urging force of the cylinder 108 (in the direction of arrow C1 in FIG. 10), and the wheel 18 is gripped by the bolt holes 22.
[0045]
Next, the cylinder 52 is urged in the opposite direction (in the direction of arrow Z2 in FIG. 7), the clamps 46 and 48 are closed, and the fixing of the wheel 18 placed on the placement portion 40 is released. The In this state, the operation of the robot 34 causes the gripping means 102 to move away in the opposite direction (in the direction of arrow C2 in FIG. 10). Then, the wheel 18 is taken out from the placement unit 40 and transferred toward the transport conveyor 36. At the same time, the cylinder 108 is urged in the opposite direction, and the claw-like members 105a and 105b of the clamp portion 104 are reduced in diameter by the retraction of the rod 108a (in the direction of arrow C2 in FIG. 10). Is released. And the wheel 18 transferred on the conveyance conveyor 36 is conveyed by post processes, such as an inspection process, for example (refer FIG. 1).
[0046]
Next, the cylinder 86 is urged in the opposite direction (in the direction of arrow X2 in FIGS. 3 and 4), the bracket 82 comes into contact with the lower stopper 94b, and the mounting portion 40 is usually moved together with the bracket 82. Return to position. Then, the welding system 12 waits until the next press-fit product 30 is supplied. Thereby, one cycle of the joining operation | work with respect to the press-fit article 30 by the welding system 12 is completed.
[0047]
As described above, according to the welding torch 10 according to the present embodiment, since the welding torch 10 is provided with the gripping means 102 for taking out the wheel 18 that has been joined, the welding torch 10 is attached. The robot 34 can be shared. As a result, the robot 34 can be simplified, and the space of the welding system 12 in which the robot 34 is installed can be saved.
[0048]
In addition, since the gripping means 102 extends in a direction intersecting with the rotation axis B of the head portion 34b of the robot 34, particularly in a direction orthogonal thereto, the welding work of the welding torch 10 and the picking up work of the gripping means 102 are performed. Mutual interference or the like caused by the can be prevented. As a result, since the interruption of the welding system 12 due to such mutual interference is avoided, the production efficiency of the wheel 18 can be improved.
[0049]
Further, since the gripping means 102 includes the clamp portion 104 that grips the wheel 18 through the bolt hole 22 of the wheel 18, when removing the wheel 18, it does not rely on manual work and other auxiliary There is no need to provide members, tools, etc., the robot 34 can be further simplified, and the production efficiency of the wheel 18 can be further improved.
[0050]
The press-fit product 30 placed on the support block 38 of the placement unit 40 is fixed by clamps 46 and 48 provided on the placement unit 40 via the hub hole 20 of the wheel disc 16, while being welded torch. The wheel 18 for which the joining work by 10 has been completed is gripped by the clamp portion 104 provided in the gripping means 102 via the bolt hole 22 of the wheel disc 16 and taken out from the mounting portion 40. Thus, since the means for fixing the wheel 18 (press-fit product 30) and the means for taking out the wheel 18 are shared, the wheel 18 is efficiently received by the gripping means 102 from the mounting portion 40. It becomes possible to pass. As a result, the production efficiency of the wheel 18 can be further improved.
[0051]
In the present embodiment, when the press-fitted product 30 is fixed to the support block 38 of the mounting portion 40, the hub hole 20 of the wheel disk 16 is used, while the wheel 18 is removed from the mounting portion 40. Exemplifies the case where the bolt hole 22 of the wheel disk 16 is used, but is not limited to this. For example, when the press-fit product 30 is fixed to the support block 38 of the mounting portion 40, the bolt hole 22, the welding system 12 may be configured to utilize the hub hole 20 when the wheel 18 is removed from the mounting portion 40.
[0052]
【The invention's effect】
According to the present invention, the following effects can be obtained.
[0053]
That is, since the gripping means for taking out the wheel is provided in the welding torch, the welding robot to which the welding torch is attached can be shared. As a result, it is possible to simplify the welding robot and to save space in the welding system in which the welding robot is installed.
[0054]
In addition, since the gripping means extends in a direction intersecting the rotation axis of the head portion of the welding robot, mutual interference between the welding torch joining operation and the gripping means take-out operation is prevented. Can do. As a result, since the interruption of the welding system due to such mutual interference is avoided, the production efficiency of the wheel can be improved.
[0055]
Further, since the gripping means includes a plurality of clamp portions for gripping the wheel via the bolt hole or hub hole of the wheel, when taking out the wheel, there is no need to rely on manual work, and other There is no need to provide an auxiliary member, a tool, etc., the welding robot can be further simplified, and the production efficiency of the wheel can be further improved.
[Brief description of the drawings]
FIG. 1 is a schematic perspective explanatory view of a welding system to which a welding torch according to the present embodiment is applied.
FIG. 2 is an explanatory view of a longitudinal section of a wheel formed by welding using the welding torch.
FIG. 3 is a perspective explanatory view of mounting / tilting means in the welding system shown in FIG. 1;
4 is a partial cross-sectional explanatory view of the mounting / tilting means shown in FIG. 3;
5 is an enlarged cross-sectional explanatory view of a mounting portion in the mounting / tilting means shown in FIG. 4;
6 is an enlarged perspective explanatory view of the mounting portion shown in FIG. 5. FIG.
7 is an enlarged cross-sectional explanatory view of a main part of the mounting portion shown in FIG.
FIG. 8 is an enlarged perspective explanatory view of a gripping means provided in the welding torch shown in FIG.
9 is an explanatory side view of the welding torch and gripping means shown in FIG. 8. FIG.
10 is another side explanatory view of the welding torch and gripping means shown in FIG. 8. FIG.
11 is an explanatory cross-sectional view of a main part showing a method for joining wheels according to Patent Document 1. FIG.
[Explanation of symbols]
10 ... welding torch 12 ... welding system
14 ... Wheel rim 16 ... Wheel disc
18 ... wheel 20 ... hub hole
22 ... Bolt hole 30 ... Press fit
32 ... Mounting / tilting means 34 ... Robot
38 ... Support block 40 ... Placement part
42 ... Insertion block 42a ... Slit
44 ... Locating pin 46, 48 ... Clamp
52, 86, 108 ... cylinder 80 ... inclined part
82, 100 ... bracket 102 ... gripping means
104: Clamping part 105a, 105b ... Claw-shaped member
106 ... pedestal part 110 ... adjustment part
112 ... Detection unit

Claims (2)

A welding torch attached to a welding robot that joins a wheel rim formed from a plate-shaped material and a wheel disc to form a wheel,
The welding torch is rotatably supported by a head portion of the welding robot, and the welding torch is provided with a gripping means for taking out the wheel.
The welding torch characterized in that the gripping means extends in a direction intersecting with a rotation axis of the head portion of the welding robot. The welding torch according to claim 1,
The welding torch characterized in that the gripping means includes a clamp portion that grips the wheel via a bolt hole or a hub hole of the wheel.

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