Tire Test Drum

Abstract

To provide a tire testing drum from which a pseudo road surface is hardly peeled off.SOLUTION: A tire testing drum 20 of an embodiment has a cylindrical drum body 21 and a pseudo road surface 22 that is provided on an outer peripheral surface of the drum body 21, and has jigs 23 that hold down portions 28 on both sides in a drum axial direction of the pseudo road surface 22 from the outsides in a drum radial direction and inserts 27 that are sandwiched between the pseudo road surface 22 and the jigs 23.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a tire testing drum. [Background technology]

[0002] For example, as disclosed in Patent Document 1, a tire test drum is known in which a simulated road surface made of aggregate and binder is provided on the outer peripheral surface of a cylindrical drum body. The simulated road surface has a certain width in the axial direction of the drum and completes one revolution in the circumferential direction of the drum.

[0003] A tire is brought into contact with the simulated road surface of such a tire test drum, and the tire is rotated by rotating the tire test drum, and various tests are performed, such as measuring noise generated by the tire. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-218470 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the tire testing drum rotates, the simulated road surface may peel off from the outer circumferential surface of the drum body due to the centrifugal force generated by the rotation of the tire testing drum. The simulated road surface peels off from the axial end of the drum where the adhesive strength between the simulated road surface and the outer circumferential surface of the drum body is weak.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tire test drum on which the simulated road surface is less likely to peel off. [Means for solving the problem]

[0007] The tire test drum of the embodiment has a cylindrical drum body and a simulated road surface provided on the outer peripheral surface of the drum body, and includes a jig that presses both sides of the simulated road surface in the drum axial direction from the outside in the drum radial direction, and an insert that is sandwiched between the simulated road surface and the jig. The portion of the simulated road surface that is pressed by the jig is thinner than the other portions. It is characterized by: Effect of the Invention

[0008] According to the tire test drum of the embodiment, the simulated road surface can be firmly pressed down on both sides of the drum in the axial direction by the jig and the insert, so that the simulated road surface is less likely to peel off from the drum body. [Brief description of the drawings]

[0009] [Figure 1] FIG. [Diagram 2] FIG. 2 is a perspective view of a tire test drum. [Diagram 3] A view of the simulated road surface from the radially outer side of the drum. [Figure 4] Cross-sectional view of the simulated road surface and jig (cross-sectional view of the simulated road surface viewed from the tangential direction of the drum circumference). [Diagram 5] Cross-sectional view of a simulated road surface with thin edges (cross-sectional view of the simulated road surface viewed from the tangential direction of the drum circumference). (a) is an example where the outer diameter of the center part of the simulated road surface is the same as the outer diameter of the jig. (b) is an example where the outer diameter of the center part of the simulated road surface is larger than the outer diameter of the jig. [Figure 6] Cross-sectional view of a simulated road surface with sloped edges (cross-sectional view of the simulated road surface viewed from the tangential direction of the drum circumference). (a) is an example where the outer diameter of the central part of the simulated road surface is smaller than the outer diameter of the jig. (b) is an example where the outer diameter of the central part of the simulated road surface is the same as the outer diameter of the jig. (c) is an example where the outer diameter of the central part of the simulated road surface is larger than the outer diameter of the jig. [Figure 7] Cross-sectional view of a simulated road surface with curved edges (cross-sectional view of the simulated road surface viewed from the tangential direction of the drum circumference). (a) is an example where the outer diameter of the central part of the simulated road surface is smaller than the outer diameter of the jig. (b) is an example where the outer diameter of the central part of the simulated road surface is the same as the outer diameter of the jig. (c) is an example where the outer diameter of the central part of the simulated road surface is larger than the outer diameter of the jig. [Figure 8] A cross-sectional view of a tire test drum near a simulated road surface, in which a metal plate is provided between the drum body and the simulated road surface (a cross-sectional view of the simulated road surface viewed from the tangential direction around the drum circumference). [Figure 9] FIG. 2 is a view of a tire test drum in which a metal plate is provided between the drum body and a simulated road surface, as viewed from the drum axial direction. [Figure 10] FIG. 2 is a view of a tire test drum on which a plurality of jigs are arranged in the circumferential direction of the drum, as viewed from the radially outer side of the drum. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The embodiments will be described with reference to the drawings. Note that the embodiments described below are merely examples, and any appropriate modifications that do not depart from the gist of the present invention are included in the scope of the present invention.

[0011] First, a tire testing device 10 will be described. The tire testing device 10 shown in Fig. 1 includes a cylindrical tire testing drum 20 that is rotatable in the drum circumferential direction, a shaft 11 that serves as the rotation axis of the tire testing drum 20, a drive unit 12 that houses a motor that rotates the shaft 11, a support shaft 13 that supports a tire T, and a support unit 14 that moves the support shaft 13 up and down to bring the tire T into contact with the tire testing drum 20 with a predetermined load. Although not shown, devices necessary for testing, such as a microphone for measuring noise, are arranged around the tire testing drum 20.

[0012] During testing, the tire T attached to the support shaft 13 is pressed against the tire testing drum 20. In this state, when the driving device unit 12 is driven to rotate the shaft 11 and the tire testing drum 20, the tire T also rotates. While the tire T is rotating, tests such as noise measurement are performed.

[0013] Next, the tire test drum 20 will be described in detail. As shown in Fig. 2 to Fig. 4, the tire test drum 20 has a cylindrical drum body 21 and a simulated road surface 22 provided on the outer peripheral surface of the drum body 21. The simulated road surface 22 has a constant width in the drum axial direction and completes one revolution in the drum circumferential direction. Furthermore, the tire test drum 20 has a jig 23 that presses both sides of the simulated road surface 22 in the drum axial direction from the outside in the drum radial direction.

[0014] The simulated road surface 22 is a mixture of aggregate and binder formed to a predetermined thickness. The aggregate may be crushed stone, sand, etc., and the binder may be epoxy resin, asphalt, cement, mortar, concrete, etc.

[0015] The preferred parameters of the simulated road surface 22 are as follows. First, the amount of unevenness in the drum circumferential direction (i.e., the difference between the maximum height and the minimum height in the drum circumferential direction) is preferably 2 mm or less. Also, the amount of unevenness in the drum axial direction (i.e., the difference between the maximum height and the minimum height in the drum axial direction) is preferably 3 mm or less. Also, the MPD (Mean Profile Depth) is preferably 0.5±0.2 mm. Also, the maximum aggregate particle size is preferably 6.3 to 10.0 mm. Also, the target grading curve of the aggregate preferably complies with JIS D8301.

[0016] The simulated road surface 22 may be formed by molding only the binder to a predetermined thickness. Regardless of the presence or absence of aggregate, the simulated road surface 22 is adhered to the outer circumferential surface of the drum body 21 by the adhesive force of the binder.

[0017] The pseudo road surface 22 has a constant thickness in the drum radial direction, and is higher in the drum radial direction than the outer circumferential surface of the drum body 21, as shown in Fig. 4. The thickness of the pseudo road surface 22 may be in the range of 30 mm or more as specified by JIS D8301, or may be in the range of 3 mm or more and 30 mm or less.

[0018] Jigs 23 are provided on both sides of the simulated road surface 22 in the drum axial direction. The jig 23 is an annular member of a size that fits into the drum body 21. The jig 23 is made of a metal such as steel, aluminum, or an alloy containing these metals, and has a strength that does not cause deformation or breakage due to the centrifugal force of the rotation of the drum body 21. As shown in FIG. 4, the jig 23 is formed with a fitting portion 25 that fits into the outer circumferential surface of the drum body 21, and a pressing portion 26 that presses the simulated road surface 22 from the outside in the drum radial direction. The pressing portion 26 is located closer to the center of the simulated road surface 22 in the drum axial direction than the fitting portion 25. The inner diameter of the fitting portion 25 is the same as the outer diameter of the drum body 21.

[0019] A plurality of screw holes (not shown) are formed in the fitting portion 25 of the jig 23. In addition, screw holes (not shown) are also formed in the drum body 21 at locations that correspond to the screw holes of the fitting portion 25. The jig 23 is fixed to the drum body 21 by passing screws 40 shown in FIG. 3 through these screw holes.

[0020] With the jig 23 fixed to the drum body 21, the fitting portion 25 of the jig 23 fits into the outer circumferential surface of the drum body 21. An end 25a of the fitting portion 25 on the side of the pseudo road surface 22 is in contact with an end in the drum axial direction of the pseudo road surface 22. The pressing portion 26 covers edge portions 28 on both sides in the drum axial direction of the pseudo road surface 22 from the outside in the drum radial direction.

[0021] The width of the edge portions 28 of the simulated road surface 22 pressed down by the pressing portions 26 is equal on both sides in the drum axial direction of the simulated road surface 22. It is preferable that the ratio of the total width L2 of the edge portions 28 pressed down by the pressing portions 26 (i.e., the total width of the edge portions 28 on both sides in the drum axial direction) to the overall width L1 of the simulated road surface 22 (see FIG. 4) is 10 to 20%. Table 1 shows examples of dimensions of the overall width L1 of the simulated road surface 22 and the total width L2 of the edge portions 28 of the simulated road surface 22 to achieve such a ratio.

[0022] [Table 1]

[0023] The cross-sectional shape of the simulated road surface 22 (the cross-sectional shape of the simulated road surface 22 seen from the tangential direction of the drum circumference) is a rectangle that is long in the drum axial direction. The simulated road surface 22 has the same thickness at the edge portion 28 that is covered and held down by the holding portion 26 of the jig 23 and at the center portion 29 that is not covered by the holding portion 26 of the jig 23.

[0024] The inner diameter of the pressing portion 26 of the jig 23 and the outer diameter of the simulated road surface 22 are manufactured to be the same or close to each other. If the inner diameter of the pressing portion 26 and the outer diameter of the simulated road surface 22 are the same, no gap will be formed between the pressing portion 26 and the simulated road surface 22 when the pressing portion 26 is placed directly on the simulated road surface 22. In reality, however, the thickness of the simulated road surface 22 varies depending on the location, which causes some locations to have no gap between the pressing portion 26 and the simulated road surface 22 and other locations to have a gap, and the size of the gap also varies depending on the location.

[0025] As an insert to fill such a gap, a rubber sheet 27 is sandwiched between the simulated road surface 22 and the pressing part 26 of the jig 23. The thickness of the rubber sheet 27 is preferably 1 mm or less. In addition, the width of the rubber sheet 27 (the length in the drum axial direction) is equal to or less than the width of the pressing part 26 of the jig 23.

[0026] The simulated road surface 22 has projections and recesses, and as described above, the size of the gap between the simulated road surface 22 and the pressing portion 26 varies depending on the location, but the gap is filled by the deformation of the rubber sheet 27. Furthermore, due to the elasticity of the rubber sheet 27, the contact pressure acting on the rubber sheet 27 is dispersed over a wide area of ​​the rubber sheet 27.

[0027] The rubber sheet 27 is provided around the drum circumferential direction while maintaining a constant width in the drum axial direction. Here, one rubber sheet 27 may have a length equivalent to one circumference of the edge portion 28 of the simulated road surface 22 on the drum main body 21, and the one rubber sheet 27 may be wrapped around the drum circumferential direction for one circumference. In this case, it is preferable that there is no gap between both ends of the rubber sheet 27 (i.e., they are in contact), but there may be a gap.

[0028] In addition, a plurality of relatively short rubber sheets 27 may be continuously arranged in the drum circumferential direction. When a plurality of rubber sheets 27 are arranged in the drum circumferential direction, it is preferable that there is no gap between the rubber sheets 27, but gaps may be present.

[0029] Next, an example of a manufacturing method of the tire test drum 20 will be described. First, the aggregate and binder that are the materials for the simulated road surface 22 are stirred and mixed to form a mixture. Next, the mixture is applied to a predetermined location on the outer circumferential surface of the drum body 21. During application, the mixture is applied to the outer circumferential surface of the drum body 21 using a frame or the like as appropriate so that the mixture does not run off or go beyond a predetermined range. After application, the surface of the mixture layer is pressed and smoothed with a roller to complete the application. Thereafter, when the mixture layer dries, the simulated road surface 22 is completed.

[0030] After the simulated road surface 22 is completed, a rubber sheet 27 is placed on the outer peripheral surface of an edge portion 28 of the simulated road surface 22. Furthermore, a jig 23 is placed on both sides of the simulated road surface 22 in the drum axial direction. As a result, the rubber sheet 27 is sandwiched between the edge portion 28 of the simulated road surface 22 and the pressing portion 26 of the jig 23. Next, the jig 23 is fixed to the drum body 21 with a screw 40. This completes the tire test drum 20.

[0031] Next, the effects of this embodiment will be described. In this embodiment, the pressing portion 26 of the jig 23 presses the edge portion 28 of the simulated road surface 22 from the outer side in the drum radial direction, so that the simulated road surface 22 can be prevented from peeling off from the end portion.

[0032] Furthermore, because the rubber sheet 27 is sandwiched between the edge portion 28 of the simulated road surface 22 and the pressing portion 26 of the jig 23, the slight gap between the simulated road surface 22 and the pressing portion 26 is filled, and the pressing portion 26 can firmly press the edge portion 28 of the simulated road surface 22. Even if the simulated road surface 22 is uneven, the contact pressure with the convex portions of the simulated road surface 22 is dispersed by the rubber sheet 27, so the jig 23 can firmly press the edge portion 28 of the simulated road surface 22 via the entire rubber sheet 27.

[0033] Furthermore, since the rubber sheet 27 is provided around the drum in the circumferential direction, the edge portion 28 of the simulated road surface 22 can be firmly pressed by the entire pressing portion 26 of the jig 23.

[0034] Furthermore, if the ratio of the total width L2 of the edge portions 28 to the overall width L1 of the pseudo road surface 22 is 10 to 20%, the jig 23 can firmly hold the pseudo road surface 22 and a sufficient area of ​​the pseudo road surface 22 that can be used for testing the tire T can be secured.

[0035] Next, a modification of the embodiment will be described.

[0036] <Change Example 1> The insert between the pressing portion 26 of the jig 23 and the edge portion 28 of the simulated road surface 22 is not limited to the rubber sheet 27, but may be any deformable member that can deform to fit the size of the gap between the jig 23 and the simulated road surface 22 and the unevenness of the simulated road surface 22. Examples of deformable members other than the rubber sheet 27 include members made of clay or flexible synthetic resin. It is preferable that the insert is elastically deformable. The preferable Young's modulus of the insert is 1 MPa to 100 MPa.

[0037] <Change Example 2> 5, in the simulated road surface 122, edge portions 128 that are pressed by the jig 23 may be thinner than a central portion 129 that is not covered by the jig 23. The edge portions 128 have a constant thickness as a whole, and the central portion 129 also has a constant thickness as a whole. In these modified examples, the same jig 23 as in the above embodiment is used.

[0038] In the modified example of Fig. 5(a), the outer circumferential surface of the central portion 129 of the pseudo road surface 122 is flush with the outer circumferential surface of the jig 23. In the modified example of Fig. 5(b), the outer diameter of the central portion 129 of the pseudo road surface 122 is larger than the outer diameter of the jig 23.

[0039] In the simulated road surface 122 of this modified example, the thickness H1 (see FIG. 5(b)) of the edge portion 128 in the drum radial direction is 50 to 100% of the thickness H2 of the central portion 129 in the drum radial direction. By making H1 50% or more of H2, it is possible to prevent the edge portion 128 from being damaged when centrifugal force is generated. Incidentally, in the simulated road surface 22 of the above embodiment shown in FIG. 4, the thickness of the edge portion 28 is 100% of the thickness of the central portion 29.

[0040] In the manufacturing method of the tire test drum of this modified example, first, a temporary simulated road surface is applied to the outer peripheral surface of the drum body 21 so that the entire surface is the same thickness as the central portion 129. Next, the edge portion of the temporary simulated road surface is scraped to form an edge portion 128 that is thinner than the central portion 129. Next, a rubber sheet 27 is placed on the outer peripheral surface of the edge portion 128, and a jig 23 is placed on the rubber sheet 27 and fixed in place.

[0041] According to these modified examples, it is possible to thicken the central portion 129 with which the tire T comes into contact while reducing the outer diameter of the jig 23. Therefore, it is possible to realize testing of the tire T on a thick simulated road surface 122 while preventing the jig 23 from coming into contact with surrounding equipment, etc.

[0042] These variations are useful when equipment is closely spaced around the tire test drum 20 or when testing on a thick simulated road surface 122 is required.

[0043] <Change Example 3> In the modified example shown in Fig. 6, an edge portion 228 of the simulated road surface 222 has a slope inclined with respect to the drum radial direction. Therefore, the cross-sectional shape of the simulated road surface 222 (the cross-sectional shape of the simulated road surface 222 viewed from the tangential direction of the drum circumferential direction) is a trapezoid. Furthermore, a pressing portion 226 of a jig 223 that presses such an edge portion 228 has a slope that is inclined at the same angle as the slope of the edge portion 228 of the simulated road surface 222. Furthermore, a rubber sheet 227 is sandwiched between the slope of the edge portion 228 of the simulated road surface 222 and the slope of the pressing portion 226 of the jig 223.

[0044] Figure 6(a) shows an example in which the outer diameter of the central portion 229 of the pseudo road surface 222 is smaller than the outer diameter of the jig 223, Figure 6(b) shows an example in which the outer diameter of the central portion 229 of the pseudo road surface 222 is the same as the outer diameter of the jig 223, and Figure 6(c) shows an example in which the outer diameter of the central portion 229 of the pseudo road surface 222 is larger than the outer diameter of the jig 223.

[0045] According to these modified examples, the thickness of the edge portion 228 of the simulated road surface 222 gradually decreases toward the end, so stress concentration is less likely to occur and the simulated road surface 222 is less likely to be damaged compared to when the thickness of the simulated road surface 222 changes suddenly depending on the location (for example, when the thickness changes discontinuously at the boundary between the center portion 229 and the edge portion 228). Also, the edge portion 228 of the simulated road surface 222 can be held down by the jig 223, which has a relatively simple shape with a slope on the inner diameter side.

[0046] <Change Example 4> 7, an edge portion 328 of the pseudo road surface 322 has a curved surface that is convex outward in the drum radial direction and convex outward in the drum axial direction. A pressing portion 326 of a jig 323 that presses such edge portion 328 has a curved surface that matches the curved surface of the edge portion 328 of the pseudo road surface 322. A rubber sheet 327 is sandwiched between the curved surface of the edge portion 328 of the pseudo road surface 322 and the curved surface of the pressing portion 326 of the jig 323.

[0047] Figure 7(a) shows an example in which the outer diameter of the central portion 329 of the pseudo road surface 322 is smaller than the outer diameter of the jig 323, Figure 7(b) shows an example in which the outer diameter of the central portion 329 of the pseudo road surface 322 is the same as the outer diameter of the jig 323, and Figure 7(c) shows an example in which the outer diameter of the central portion 329 of the pseudo road surface 322 is larger than the outer diameter of the jig 323.

[0048] According to these modified examples, the thickness of edge portion 328 of pseudo road surface 322 gradually decreases toward the end, so stress concentration is less likely to occur and pseudo road surface 322 is less likely to be damaged compared to a case where the thickness of pseudo road surface 322 changes suddenly depending on the location (for example, a case where the thickness changes discontinuously at the boundary between center portion 329 and edge portion 328). Also, edge portion 328 of pseudo road surface 322 can be held down with jig 323, which has a relatively simple shape with a curved surface on the inner diameter side.

[0049] <Change Example 5> As shown in FIG. 8, a metal part 400 may be provided as a lower layer on the outer circumferential surface of the drum body 21, and the pseudo road surface 22, the rubber sheet 27 and the jig 423 may be provided on the outer circumferential surface of the metal part 400.

[0050] As shown in Fig. 9, the metal part 400 is formed by arranging a plurality of (eight in Fig. 9) metal plates 401 in the drum circumferential direction with no gaps. Each metal plate 401 is curved with a curvature that matches the outer peripheral surface of the drum body 21, and is in close contact with the outer peripheral surface of the drum body 21. The metal plates 401 are fixed to the drum body 21 with fasteners such as screws. In addition, the jig 423 is fixed to the metal plates 401 with fasteners such as screws.

[0051] 9, the jig 423 is divided in the drum circumferential direction at the same positions as the metal plate 401. However, as in the above embodiment, an annular jig that goes around the drum circumferential direction may be provided.

[0052] As an example of a method for manufacturing a tire test drum having a metal portion 400, first, the pseudo road surface 22 is applied on a metal plate 401. Next, the metal plate 401 with the pseudo road surface 22 is arranged and fixed to the drum body 21. Next, jigs 423 are fixed to both sides of the pseudo road surface 22 in the drum axial direction.

[0053] According to this modification, the simulated road surface can be easily changed according to the purpose of the test by replacing the metal part 400. In addition, by using such a metal part 400, the outer circumferential surface of the drum body 21 can be prevented from being damaged.

[0054] A layer of a material other than metal, such as a synthetic resin, may be provided as an underlayer between the drum body 21 and the pseudo road surface 22. In this case, plates in place of the metal plate 401 are provided on the outer circumferential surface of the drum body 21 in the drum circumferential direction.

[0055] <Change Example 6> As shown in Fig. 10, multiple jigs 523 may be arranged side by side in the circumferential direction of the drum. In Fig. 10, multiple jigs 523 are arranged at regular intervals in the circumferential direction of the drum, but multiple jigs 523 may be arranged without intervals in the circumferential direction of the drum. [Explanation of symbols]

[0056] T... tire, 10... tire testing device, 11... shaft, 12... drive unit, 13... support shaft, 14... support unit, 20... tire testing drum, 21... drum body, 22... simulated road surface, 23... jig, 25... fitting portion, 25a... end portion, 26... holding portion, 27... rubber sheet, 28... edge portion, 29... center portion, 40... screw, 122... simulated road surface, 128... edge portion, 129... center portion, 222... simulated road surface, 223... jig, 226... holding portion, 227... rubber sheet, 228... edge portion, 229... center portion, 322... simulated road surface, 323... jig, 326... holding portion, 327... rubber sheet, 328... edge portion, 329... center portion, 400... metal portion, 401... metal plate, 423... jig, 523... jig

Claims

1. A tire test drum having a cylindrical drum body and a simulated road surface provided on an outer peripheral surface of the drum body, A jig for pressing both sides of the pseudo road surface in the axial direction of the drum from the outer side in the radial direction of the drum; and an insert sandwiched between the simulated road surface and the jig; A tire test drum, characterized in that a portion of the simulated road surface that is pressed by the jig is thinner than other portions.

2. 10. The tire test drum of claim 1, wherein the insert is a rubber member.

3. 3. The tire testing drum according to claim 1, wherein the insert is provided around the drum body in the circumferential direction of the drum.

Images