JP2016156621A - Method for measuring gap between tire and rim - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for measuring the gap between a tire and a rim with high accuracy.SOLUTION: The method for measuring the gap between a tire and a rim includes a gap molding step and a gap measuring step. The gap molding step inserts a molding material into the gap between the tire and the rim of a rimmed tire assembly and forms a molding body. The molding body molds the gap between the rim and the tire. The gap measuring step measures the shape of the molding body, thereby measuring the shape of the gap between the tire and the rim.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for measuring a gap between a rim-assembled tire and a rim.

  Tires that are inferior in uniformity cannot fully exhibit their original performance such as handling stability, ride comfort, and fuel consumption. Inferiority to this uniformity can be one of the causes of vehicle vibration and noise. This uniformity is important in improving tire performance. This uniformity is evaluated as a tire assembly in which a tire is embedded in a rim. In the tire assembly, the bead portion of the tire and the rim are in contact with each other. In the tire assembly in which the bead portion and the rim are not properly in contact with each other, the original uniformity cannot be evaluated.

  Japanese Patent Application Laid-Open No. 2006-47248 discloses a method for improving the accuracy of uniformity measurement by improving the contact between the tire and the rim. Japanese Unexamined Patent Application Publication No. 2012-42472 discloses a method for evaluating the contact state between a bead portion of a tire and a rim. These methods contribute to proper contact between the tire and the rim. These methods contribute to improvement in measurement accuracy of tire uniformity.

JP 2006-47248 A JP 2012-42472 A

  However, these methods cannot grasp the gap between the tire bead and the rim. It is difficult to accurately grasp the contact state between the tire and the rim.

  An object of the present invention is to provide a clearance measurement method capable of grasping a clearance between a tire and a rim with high accuracy.

  The method for measuring a clearance between a tire and a rim according to the present invention includes a clearance formation step and a clearance measurement step. In this gap drawing process, a drawing material is inserted between the tire and the rim of the rim-assembled tire assembly to form a drawing body. This elephant body is shaped like a gap between the rim and the tire. In this gap measurement process, the shape of the gap between the tire and the rim is measured by measuring the shape of the figure.

  Preferably, the gap measuring method includes a break-in process prior to the gap drawing process. In this break-in process, the air is extracted after the tire assembly assembled with the rim is filled with air. In the gap drawing process, a drawing material is inserted between the tire and the rim in the tire assembly from which the air has been removed. After the elephant material is inserted, the tire is filled with air to model the shape of the gap between the tire and the rim.

  Preferably, the gap measuring method includes a uniformity measuring step prior to the gap drawing step. In this uniformity measurement step, the circumferential position of the tire assembly and the magnitude of the force at that position are measured. A circumferential position where the magnitude of this force is maximum or minimum is determined. In the gap drawing step, the shape of the gap between the tire and the rim is drawn at a circumferential position where the magnitude of the force measured in the uniformity measurement step is maximized or minimized.

  Preferably, in the gap drawing step, the shape of the gap between the tire and the rim is drawn at a plurality of circumferential positions.

  Preferably, the plurality of circumferential positions are equally spaced in the circumferential direction.

  Preferably, in the gap measuring step, the circumferential position where the thickness of the figure is maximized and the maximum value of the thickness are measured.

  In the gap measuring method according to the present invention, the shape of the gap is formed. By observing this figure, the state of the gap can be visually observed. By this method, the shape and size of the gap between the tire and the rim can be grasped with high accuracy.

FIG. 1 is a flowchart illustrating a gap measuring method according to an embodiment of the present invention. FIG. 2 is an explanatory view showing a tire assembly measured by the gap measuring method of FIG. FIG. 3 is an explanatory diagram of the gap measuring method of FIG. FIG. 4 is a graph showing the radial force variation of the tire of FIG. FIG. 5 is another explanatory diagram of the gap measuring method of FIG. FIG. 6 is an explanatory view showing a figure obtained by the gap measuring method of FIG.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 is a flowchart of a gap measuring method according to the present invention. This flowchart shows an example of this measurement method. This measurement method includes a break-in process, a uniformity measurement process, a gap formation process, and a gap measurement process.

  This gap measuring method will be described by taking the tire assembly 2 of FIG. 2 as an example. This tire assembly 2 is obtained by incorporating a tire 4 into a rim 6. The tire 4 is a pneumatic tire. In FIG. 2, the vertical direction is the radial direction of the tire 2, the horizontal direction is the axial direction of the tire 2, and the direction perpendicular to the paper surface is the circumferential direction of the tire 2.

  The tire 4 includes a tread portion 8, a pair of sidewall portions 10, and a pair of bead portions 12. The tread portion 8 is located on the outer side in the radial direction. The tread portion 8 has a shape protruding outward in the radial direction. The outer surface in the radial direction of the tread portion 8 forms a tread surface 14 that contacts the road surface.

  Each sidewall portion 10 extends substantially inward in the radial direction from the axial end of the tread portion 8. The radially outer end of the sidewall portion 8 is joined to the tread portion 8. The radially inner end of the sidewall portion 10 is joined to the bead portion 12. The sidewall portion 10 absorbs an impact from the road surface by bending.

  Each bead portion 12 is positioned substantially inside the sidewall portion 10 in the radial direction. The bead portion 12 includes a bottom surface 16 facing inward in the radial direction and an outer surface 18 facing outward in the axial direction. The outer surface 18 is a surface extending continuously outward from the bottom surface 16 in the radial direction. When the tire 4 is incorporated into the rim 6, the bottom surface 16 and the outer surface 18 come into contact with the rim 6.

  Although not shown, one of the pair of axial side surfaces of the tire 4 is the DOT side (the side on which the date of manufacture is marked), and the other side is the N-DOT side (the date of manufacture, etc.). This is the side of the side that is not marked.

  The rim 6 is a regular rim of the tire 4. The rim 6 is a “standard rim” in the JATMA standard. The rim 6 includes a well 20, a bead seat 22 and a flange 24. The well 20, the bead sheet 22, and the flange 24 are rounded in the circumferential direction and formed into a cylindrical shape. In the cross section of FIG. 2, the well 20 is recessed inward in the radial direction at substantially the center in the axial direction. A bead sheet 22 extends axially outward from the well 20. A flange 24 extends radially outward from the outside in the axial direction of the bead sheet 22. A radially outer end of the flange 24 is bent and extends outward in the axial direction.

  The bead sheet 22 includes a sheet surface 26. The sheet surface 26 is formed by the outer peripheral surface of the bead sheet 22. The flange 24 includes a contact surface 28. The contact surface 28 extends radially outward from the seat surface 26 of the bead sheet 22. One contact surface 28 in the axial direction and the other contact surface 28 face each other. When the tire 2 is incorporated into the rim 6, the bottom surface 16 of the bead portion 12 contacts the seat surface 26, and the outer surface 18 contacts the contact surface 28.

  In this measurement method, the rim 6 may be a rim defined by the standard. Here, the “standard rim” in the JATMA standard is exemplified as the regular rim. The rim 6 may be “Design Rim” in the TRA standard or “Measuring Rim” in the ETRTO standard.

  A method for measuring a gap between the tire 4 and the rim 6 according to the present invention will be described. Here, the gap measuring method of FIG. 1 will be described using the tire assembly 2 of FIG. 2 as an example.

  In the break-in process of FIG. 1, the tire 4 and the rim 6 are prepared. A lubricant is applied to the bead portion 12 shown in FIG. This lubricant is applied to the bottom surface 16 of the bead portion 12 on both the DOT side and the N-DOT side. A lubricant is applied from the toe to the heel of the bead portion 12. A lubricant may also be applied to the outer surface 18 of the bead portion 12. The tire 4 is incorporated in the rim 6 of FIG.

  The tire assembly 2 (tire 4) is filled with air. For example, the tire 4 is filled with air of normal internal pressure. As shown in FIG. 3C, the bottom surface 16 of the bead portion 12 contacts the seat surface 26 of the rim 6. The outer surface 18 of the bead portion 12 contacts the contact surface 28 of the rim 6. In this way, the tire assembly 2 of FIG. 2 is obtained. The bottom surface 16 of the tire 4 is in contact with the seat surface 26 of the rim 6, and the outer surface 18 is in contact with the contact surface 28. The tire 4 is properly assembled in the rim 6. This air pressure is not necessarily a normal internal pressure. If the tire 4 is properly assembled in the rim 6, this air pressure may be higher or lower than the normal internal pressure.

  In the uniformity measurement step, the uniformity of the tire assembly 2 filled with air is measured. The force variation is measured using a force variation tester in accordance with the uniformity test conditions of JASO C607: 2000. For example, RFV (radial force variation) is measured. In this RFV measurement, the tire assembly 2 is attached to the rotating shaft. A radial load is applied to the tire assembly 2. The radial force that appears on the rotation shaft when the tire assembly 2 is rotated while the height of the rotation shaft is constant is measured. This radial force variation is measured.

  FIG. 4 shows a graph of RFV measurement results of the tire assembly 2. The horizontal axis θ of this graph represents the circumferential rotation angle of the tire assembly 2. This angle θ represents the position in the circumferential direction. The 0 ° position of the angle θ is an arbitrary position in the circumferential direction. This arbitrary position is previously marked. The vertical axis F indicates the magnitude of the radial force appearing on the rotation axis. The magnitude of this force varies depending on the rotation of the tire assembly 4 from an angle of 0 ° to 360 °.

  Fa (N) in FIG. 4 represents the maximum value of the force in the radial direction. θa (°) represents an angle at the maximum value Fa (N). Fb (N) represents the minimum value of the force in the radial direction. θb (°) represents an angle at the minimum value Fb (N). Marks are attached in the circumferential direction of the tire assembly 2. One mark is attached at a position of an angle θa (°) in the circumferential direction. Further, another mark is attached at a position of an angle θb (°) in the circumferential direction. This mark is attached to both side surfaces of the DOT side and the N-DOT side. As this mark, a common mark on both side surfaces may be attached to one side surface or the tread surface 14. The tire assembly 2 is sent to the gap drawing process.

  In the gap drawing process, the drawing material 32 is prepared. As this elephant material 32, the brand name Exa Fine (made by GC Corporation) which is a vinyl silicone impression material is illustrated. This impression material is obtained by mixing a base paste and a catalyst paste. After the impression material is mixed, the impression material starts to harden after a predetermined time, and finally, a cured body as the figure 34 is obtained.

  In this gap drawing process, air is extracted from the tire assembly 2. After the air is removed, the base paste and the catalyst paste are mixed to prepare the elephant 32. A gap is formed on the side surface of the tire 4 on the DOT side. As shown in FIG. 5A, at the position of one mark, that is, at the position of the angle θa (°) in the circumferential direction, the tire lever 30 is interposed between the bead portion 12 of the tire 4 and the flange 24 of the rim 6. Is inserted. The gap between the outer surface 18 and the contact surface 28 is pushed wide. The elephant material 32 is inserted into the widened gap. Similarly, for example, the figurine 32 is inserted into the gap between the bead portion 12 and the flange 24 at another mark position, that is, at a position of an angle θb (°) in the circumferential direction.

  After the figure 32 is inserted in all the circumferential positions to be measured, the tire assembly 2 is filled with air. The tire 4 is filled with air of normal internal pressure. Filled with air, the bead portion 12 comes into contact with the flange 24 as shown in FIG. In FIG. 5 (b), the gap between the outer surface 18 and the contact surface 28 is filled with the figure material 32. In the state shown in FIG. 5B, the substrate is left at room temperature for a predetermined time, for example, 0.5 hours. The predetermined time that is allowed to stand may be a time sufficient for the figurine 32 to harden into the figurine 34 at room temperature.

  After the predetermined time has elapsed, the air is extracted from the tire assembly 2. As shown in FIG. 5C, the contact between the tire 4 and the rim 6 is released. The figure 34 is taken out between the tire 4 and the rim 6.

  On the side surface of the tire 4 on the N-DOT side, a gap formation process is performed in the same manner as the side surface on the DOT side. Also on the side surface on the N-DOT side, the figure 34 is taken out from between the bead portion 12 of the tire 4 and the flange 24 of the rim 6 at the position of one mark. The figure 34 is taken out between the bead portion 12 and the flange 24 at the position of another mark.

  FIGS. 6A and 6B show the elephant body 34 thus taken out. FIG. 6A shows the figure 34 viewed in the axial direction. FIG. 6B shows a cross section perpendicular to the circumferential direction of the figure 34. The cross section of FIG. 6B is a cross section at a circumferential position where the thickness of the figure 34 is maximum. A double-headed arrow T in FIG. 6B represents this maximum thickness.

  In the gap measuring step, the shape of the extracted figure 34 is measured. The maximum thickness T in FIG. 6B is measured. This maximum thickness T is measured as the distance between the bead contact surface 36 formed by the bead portion 12 and the rim contact surface 38 formed by the rim 6. This maximum thickness T is measured as a thickness in a direction perpendicular to the bead contact surface 36. This maximum thickness T is preferably measured with a precision thickness meter. This maximum thickness T is preferably measured with an accuracy of 0.01 mm. The maximum thickness T may be measured with higher accuracy than the 0.01 mm unit.

  In the gap drawing process of this gap measurement method, the figure body 34 is shaped like a gap in the gap drawing process. In the gap measuring step, the shape of the figure 34 is measured. It is difficult to directly measure the gap between the tire 4 and the rim 6. By using this figure 34, the shape of the gap can be visually confirmed. By measuring the shape of the elephant body 34, the gap between the tire 4 and the rim 6 is measured with high accuracy.

  The method of FIG. 1 includes a break-in process prior to the gap drawing process. When the tire 4 is incorporated in the rim 6, the positional relationship between the bead portion 12 and the rim 6 varies. By providing the break-in process, this variation is reduced. By providing this break-in process, the shape of the gap can be accurately modeled. In this gap measurement method, a break-in process is not essential, but this gap measurement method preferably includes a break-in process.

  The method of FIG. 1 includes a uniformity measurement step prior to the gap drawing step. The gap is likely to be maximized at the circumferential position of the maximum value Fa (N) and the circumferential position of the minimum value Fb (N) in FIG. By measuring the gap at the circumferential position of the angle θa (°) and the angle θb (°), the size of the gap can be measured with high accuracy. By providing the uniformity measurement step, the gap measurement point can be appropriately selected. In this gap drawing process, the gap is drawn at the circumferential position of the angle θa (°) and the angle θb (°), but the gap is drawn at the circumferential position of the angle θa (°) or the angle θb (°). An elephant may be made. In this gap measurement method, the uniformity measurement step is not essential, but the gap measurement method preferably includes a uniformity measurement step.

  In this gap drawing step, the shape of the gap between the tire 4 and the rim 6 may be drawn at a plurality of circumferential positions. By imaging at a plurality of circumferential positions, the state of the gap in the entire circumferential direction can be grasped. The plurality of circumferential positions may be equally spaced in the circumferential direction. By imaging at equal intervals, the state of the gap in the entire circumferential direction can be grasped with higher accuracy. For example, the image may be drawn at three circumferential positions, four circumferential positions, or five or more circumferential positions. The plurality of circumferential positions may be formed by combining the circumferential position of the angle θa (°) and / or the circumferential position of the angle θb (°). Further, either or either of the circumferential position of the angle θa (°) and the circumferential position of the angle θb (°) may be one of a plurality of circumferential positions that are equally spaced.

  In the gap measuring step, the circumferential position where the thickness of the figure 34 is maximum is specified. The thickness at this circumferential position is measured. Thereby, the magnitude | size and circumferential direction position of the clearance gap between the tire 4 and the rim | limb 6 can be grasped | ascertained easily.

  The figure 32 used in this measurement method is a viscous substance that fills the gap between the tire 4 and the rim 6. It is preferable that the engraved material 32 is fluid in the initial state, has good wettability, does not easily generate bubbles, and cures with time to finally become a solid. The elephant 32 is deformed into the shape of the inserted space, and then cured to become an elephant 34. The shape of the elephant body 34 is the shape of the space in which the elephant material 32 is inserted.

  The figurine material 32 whose curing starts slowly is easy to model the shape of the gap with high accuracy. From this point of view, the time from when the elephant 32 can be inserted into the gap until the elephant starts to harden is preferably 2 minutes or more, and more preferably 2 minutes 30 seconds or more. . On the other hand, the figurine 32 that takes a long time to complete curing can be shaped like a gap in a short time. This figure material 32 is excellent in workability. From this point of view, the time from when the figure member 32 can be inserted into the gap until the figure member 32 becomes the figure body 34 is preferably within 15 minutes, and more preferably within 10 minutes. Yes, particularly preferably within 5 minutes.

  In this method, the impression material used as the elephant 32 is mixed with different materials. After the different materials are mixed, they begin to cure in a predetermined time. Furthermore, the elephant body 34 is obtained as time elapses. As shown in this example, an impression material in which two or more different materials are mixed together so that the figure material 32 can be inserted into the gap is easy to start curing and to complete curing. I can grasp. Such an impression material is particularly suitable for the figure material 32.

  In the measurement method of FIG. 1, the gap drawing process was performed separately for the DOT side and the N-DOT side. In this way, by being shaped for each side surface of the tire assembly 2, it is easy to be inserted into the gap between the bead portion 12 and the flange 24 before the engraved material 32 is cured. By dividing the gap drawing process into the DOT side and the N-DOT side, the drawing of the gap is facilitated. In this method, the gap drawing process may be performed on both sides together without separating the DOT side and the N-DOT side.

  In this uniformity measurement process, RFV was explained as an example. With this RFV, radial force variations are measured. This uniformity measurement process is not limited to RFV. In the uniformity measurement step, the uniformity in the circumferential direction of the tire assembly 2 may be measured. For example, it may be a lateral force variation (LFV) in which axial force variation is measured. It may be a tractive force variation (TFV) in which a variation in force in the circumferential direction is measured.

  In this manner, the contact between the tire 4 and the rim 6 can be easily improved by grasping the shape of the gap between the tire 4 and the rim 6 with high accuracy. For example, the shape of the bead portion 12 of the tire 4 is changed from the shape of the elephant body 34. By changing the shape of the bead part 12, the tire 4 and the rim 6 can be easily brought into contact with no gap.

  The method described above can be widely applied to tires used by incorporating rims. This method can be applied not only to pneumatic tires but also to solid tires (solid tires).

2 ... Tire assembly 4 ... Tire 6 ... Rim 8 ... Tread part 10 ... Side wall part 12 ... Bead part 14 ... Tread surface 16 ... Bottom surface 18 ... Outer surface 20 ... Well 22 ... Bead sheet 24 ... Flange 26 ... Sheet surface 28 ... Abutting surface 30 ... Tyre lever 32 ... Hidden material 34. ..Elephant body 36 ... Bead contact surface 38 ... Rim contact surface

Claims (6)

It has a gap drawing process and a gap measurement process,
In this gap drawing process, the figure body is formed by inserting the figure material between the tire and the rim of the rim-assembled tire assembly, and this figure body is the gap between the rim and the tire. Shaped in shape,
In this gap measuring step, a gap measuring method between the tire and the rim is measured by measuring the shape of the figure and measuring the shape of the gap between the tire and the rim. Prior to the gap drawing process, it has a break-in process,
In this break-in process, after the rim-assembled tire assembly is filled with air, the air is removed.
In the gap drawing process, in the tire assembly from which the air has been removed, the drawing material is inserted between the tire and the rim, and after the drawing material is inserted, the tire is filled with air and the tire The gap measuring method according to claim 1, wherein the gap is shaped like a gap with a rim. Prior to the gap drawing process, it has a uniformity measurement process,
In this uniformity measurement step, the circumferential position of the tire assembly and the magnitude of the force at that position are measured, and the circumferential position where the magnitude of this force is maximum or minimum is determined,
3. The gap forming step represents the shape of the gap between the tire and the rim at a circumferential position where the magnitude of the force measured in the uniformity measurement step is maximized or minimized. The gap measuring method described in 1.   The gap measuring method according to claim 1, wherein, in the gap drawing step, the shape of the gap between the tire and the rim is drawn at a plurality of circumferential positions.   The gap measuring method according to claim 4, wherein the plurality of circumferential positions are equally spaced in the circumferential direction.   The gap measuring method according to claim 1, wherein in the gap measuring step, a circumferential position where the thickness of the figure is maximum and a maximum value of the thickness are measured.

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