JP6552937B2 - Tire stiffness measuring device and stiffness measuring method - Google Patents

Description

  The present invention relates to a stiffness measuring device and a stiffness measuring method for measuring the stiffness of a tire.

  In recent years, in order to develop a pneumatic tire with improved performance such as ride comfort, steering stability, and fuel economy, there is a growing demand to accurately measure the rigidity of the pneumatic tire, particularly the rigidity of the side portion. .

  In the following Patent Document 1, a tire support shaft that is slidable and rotatable along a slide rail is placed on a horizontal slide rail laid on a frame, and a torsional rigidity is provided on the tire support shaft. Connected to a rotary drive with detection means for measuring the lateral stiffness, and a drive with detection means for measuring the lateral stiffness, and clamping the outer peripheral surface of the tire attached to the tire support shaft to one side of the frame An apparatus for measuring the stiffness of a tire is described, characterized in that a clamping means is provided, and a driving device provided with detection means for measuring the longitudinal stiffness of the tire is connected to the clamping means. With this rigidity measurement device, it is possible to measure the torsional stiffness (also called in-plane torsional stiffness), lateral stiffness and longitudinal stiffness around the tire rotation axis, but the stiffness around an axis orthogonal to the tire rotation axis (out-plane torsion) (Also called stiffness) can not be measured.

  In the following Patent Document 2, a cantilever type tire support shaft disposed in a horizontal direction and an outer peripheral surface of a tire mounted on a wheel rim and supported by the tire support shaft via a rim hub surface are sandwiched. A tire stiffness measuring device is described that includes a clamp device, and relatively displaces the center of the wheel and the outer peripheral surface of the tire held by the clamp device to deform the tire and measure the stiffness of the tire. In this rigidity measuring device, a deformation means relatively rotating the clamp device and the wheel about an axis orthogonal to the rotation axis of the wheel to deform the tire clamped by the clamp device about the axis orthogonal to the rotation axis of the wheel; Since it has a sensor that detects the amount of deformation about an axis orthogonal to the rotational axis direction of the tire, it is possible to measure the out-of-plane torsional rigidity.

  However, in the stiffness measuring device of Patent Document 2, only the outer peripheral surface (tread surface) of the measurement tire is clamped by four arc plate segments, and the shoulder portion of the measurement tire is not sufficiently restricted. When measuring the lateral rigidity of the side portion, the influence of the rigidity of the tread portion is involved, and it is difficult to accurately measure the lateral rigidity of the side portion.

Unexamined-Japanese-Patent No. 1-156635 Unexamined-Japanese-Patent No. 6-129953

  Therefore, an object of the present invention is to provide a tire stiffness measuring device and a stiffness measuring method capable of accurately measuring the stiffness of the side portion.

The above object can be achieved by the present invention as described below.
That is, the tire stiffness measuring device of the present invention is
A tire support shaft to which a tire is attached at the tip;
A plurality of center clamps arranged at equal intervals in the tire circumferential direction and constraining the tread surface of the tire attached to the tire support shaft in the tire radial direction;
A shoulder clamp which is disposed on both sides of the center clamp in the tire width direction and which restrains a shoulder portion of the tire attached to the tire support shaft in the tire width direction;
And a rigidity measurement means for measuring the rigidity of the tire by deforming the tire by relatively displacing the tread surface restrained with the tire support shaft and the shoulder portion.

  According to the tire rigidity measuring device according to this configuration, in addition to the center clamp that restrains the tread surface of the tire in the tire radial direction, the tread portion is provided because it has a shoulder clamp that restrains the shoulder portion of the tire in the tire width direction. The stiffness of the tire can be measured under conditions close to a completely restrained state. Thereby, the rigidity of the side part can be accurately measured without being substantially affected by the rigidity of the tread part.

  In the tire rigidity measuring device according to the present invention, the shoulder portion pressing surface of the shoulder clamp for pressing the shoulder portion of the tire has a height of 10 to 30 mm from the outer surface at the center in the tire width direction of the center clamp. preferable.

  According to this configuration, the shoulder clamp can be appropriately restrained by the shoulder clamp, and the shoulder clamp does not hit the side section and does not adversely affect the rigidity measurement of the side section.

Further, the tire stiffness measurement method of the present invention includes:
Attaching the tire to the tip of the tire support shaft;
With respect to the tire attached to the tire support shaft, the tread surface is restrained in the tire radial direction by a plurality of center clamps arranged at equal intervals in the tire circumferential direction, and disposed on both sides of the center clamp in the tire width direction A step of restraining the shoulder portion in the tire width direction with the shoulder clamp made,
And C. the tire support shaft and the constrained tread surface and the shoulder portion are relatively displaced to deform the tire and measure the rigidity of the tire.

  According to the method of measuring the rigidity of a tire according to this configuration, in addition to restraining the tread surface of the tire in the radial direction of the tire by the center clamp, the tread portion is completely restrained in order to restrain the shoulder portion of the tire by the shoulder clamp. The stiffness of the tire can be measured under conditions close to the state of being restrained. Thereby, the rigidity of the side part can be accurately measured without being substantially affected by the rigidity of the tread part.

In the tire rigidity measuring method of the present invention, the center clamp is moved from the outer peripheral side to the tread surface, and moved inward in the tire radial direction until the reaction force from the tread surface becomes a first predetermined value. To restrain the tread surface,
After restraining the tread surface, the shoulder clamp is made to approach the shoulder portion from the outside in the tire width direction, and is moved inward in the tire width direction until the reaction force from the shoulder portion becomes a second predetermined value. It is preferable to restrain the shoulder portion.

  According to this configuration, the tread surface of the tire can be reliably restrained in the tire radial direction by the center clamp, and the shoulder portion of the tire can be reliably restrained in the tire width direction by the shoulder clamp.

Side view of tire stiffness measuring device Front view of tire stiffness measuring device A partial enlarged view of the stiffness measuring device of FIG. 1 Diagram schematically showing the process of restraining the tire

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a tire stiffness measuring device (note that a part of the tire stiffness measuring device is cut for illustration). FIG. 2 is a front view of the tire stiffness measuring device shown in FIG. FIG. 3 is an enlarged view showing a part of FIG. 1 in an enlarged manner.

  As shown in FIG. 1, the tire stiffness measurement apparatus includes a tire support portion 1 and a tire restraint portion 2.

  The tire support portion 1 is provided with a tire support shaft 11 to which a tire T is attached at the tip. The tire T is attached to the tire support shaft 11 via a wheel 11a. A tire force load cell 12 (a part of stiffness measuring means) is attached to the tip of the tire support shaft 11. Specifically, the tire force load cell 12 is a six-component force meter, and forces in the directions of three axes (X, Y, Z) and torques about the three axes (X, Y, Z) Can be measured. In the present embodiment, the tire axial direction is taken as a Y-axis, the lateral direction orthogonal to the Y-axis as a Z-axis, and the longitudinal direction orthogonal to the Y-axis as an X-axis.

  An in-plane torsion motor 13 is attached to an intermediate portion of the tire support shaft 11. The in-plane torsion motor 13 is a motor for rotating the tire T by rotating the tire support shaft 11. The base end portion of the tire support shaft 11 is fixed to the bearing portion 14.

  The bearing portion 14 can move in the Y-axis direction by driving the lateral displacement motor 15. Thereby, the tire support shaft 11 fixed to the bearing portion 14 can be moved in the Y-axis direction. The lateral displacement motor 15 is attached to the top of the frame 16. The frame 16 can be moved in the Z-axis direction by driving an out-of-plane torsion motor 17.

  The tire restraint portion 2 is provided with clamping means for restraining the tire T attached to the tire support shaft 11 from the outside.

  The clamp means includes a center clamp 21 that restrains the tread surface of the tire T in the tire radial direction, and a shoulder clamp 22 that restrains the shoulder portion of the tire T in the tire width direction.

  A plurality of center clamps 21 are arranged at equal intervals in the tire circumferential direction. In the present embodiment, twelve center clamps 21 are arranged, but the present invention is not limited to this. The center clamp 21 has an arc plate shape having a curvature corresponding to the curvature of the outer peripheral surface of the tire T.

  The center clamp 21 can be moved inward and outward in the tire radial direction by driving a center clamp driving motor 23. That is, when the center clamp driving motor 23 is rotationally driven, each center clamp 21 moves inward or outward in the tire radial direction, and restrains or releases the tread surface of the tire T attached to the tire support shaft 11.

  The center clamp 21 is attached to the tip of the rod 24, and the rod 24 moves by driving the center clamp driving motor 23. A part of the rod 24 and the center clamp driving motor 23 are accommodated in an annular case 25. An eccentric displacement motor 26 is provided below the annular case 25, and the annular case 25 can move in the Z-axis direction. By moving the annular case 25 in the Z-axis direction, the tread surface and the shoulder portion of the restrained tire T can be moved in the Z-axis direction.

  A load cell 27 for center clamp is provided on the back of the center clamp 21, and the load in the tire radial direction applied to the center clamp 21 can be measured.

  The shoulder clamps 22 are disposed on both sides of each center clamp 21 in the tire width direction. The shoulder clamp 22 has an arc plate shape having substantially the same curvature as the center clamp 21. The shoulder clamp 22 can be moved in the tire width direction along the surface of the center clamp 21 by driving the shoulder clamp drive motor 28.

  A shoulder clamp load cell 29 is provided outside the shoulder clamp 22 in the tire width direction, and the load in the tire width direction applied to the shoulder clamp 22 can be measured.

  A shoulder portion pressing surface 22 a that presses the shoulder portion of the tire T is formed at the tire width direction inner end of the shoulder clamp 22. The shoulder portion pressing surface 22 a is inclined with respect to the outer surface of the center clamp 21, and the inclination angle θ with respect to the outer surface of the center clamp 21 is preferably 40 to 50 °. If the inclination angle θ of the shoulder portion pressing surface 22a is smaller than 40 °, the shoulder portion cannot be properly restrained, and if it is larger than 50 °, the side portion will not be able to be accurately measured by hitting the side portion.

  Moreover, it is preferable that the height h from the outer surface of the center of the tire width direction of the center clamp 21 is 10 to 30 mm. The height h of the shoulder pressing surface 22a is the height from the outer surface of the center clamp 21 to the upper end of the shoulder pressing surface 22a, and the lower end of the shoulder pressing surface 22a is separated from the center clamp 21. Good. If the height h of the shoulder portion pressing surface 22a is lower than 10 mm, the shoulder portion cannot be restrained properly, and if it is higher than 30 mm, the side portion will hit the side portion and the rigidity of the side portion cannot be measured accurately.

  The rigidity of the tire is measured by relatively displacing the tire support shaft 11 and the restrained tread surface and shoulder portion to deform the tire. Specifically, the tire support shaft 11 or the clamping means (center clamp 21 and shoulder clamp 22) are moved by the eccentric displacement motor 26, the lateral displacement motor 15, the in-plane torsion motor 13, and the out-of-plane torsion motor 17. The stiffness of the tire is determined from the displacement of the tire T when moved and the force or torque measured by the tire force load cell 12.

  Next, a stiffness measurement method using the tire stiffness measurement device of the present embodiment will be described. First, the tire T is attached to the wheel 11 a at the tip of the tire support shaft 11. Next, the tire restraining portion 2 is moved to the position shown in FIGS. At this time, the distance between the shoulder clamps 22 on both sides is wider than the width of the tire T, as shown in FIG. 4 (a).

  Next, the clamping means including the center clamp 21 and the shoulder clamp 22 is brought closer to the tire T from the outer peripheral side. When the clamping means is approached from the outer peripheral side to the tread surface of the tire T, only the center clamp 21 first contacts the tread surface of the tire T as shown in FIG. 4 (b). After contacting the tread surface, the center clamp 21 is moved inward in the tire radial direction until the reaction force from the tread surface, that is, the load measured by the center clamp load cell 27 reaches a first predetermined value. Thereby, the tread surface of the tire T can be reliably restrained in the tire radial direction by the center clamp 21.

  After restraining the tread surface, as shown in FIG. 4C, the distance between the shoulder clamps 22 on both sides is narrowed to make the shoulder clamps 22 approach the shoulder portion from the outside in the tire width direction. Contact the shoulder portion of the tire T. After contacting the shoulder portion, the shoulder clamp 22 is moved inward in the tire width direction until the reaction force from the shoulder portion, that is, the load measured by the shoulder clamp load cell 29 becomes the second predetermined value. Thereby, the shoulder part of the tire T can be reliably restrained in the tire width direction by the shoulder clamp 22.

  Next, the tire is deformed by relatively displacing the tire support shaft 11 and the restrained tread surface and shoulder portion, and the tire stiffness is measured. For example, the tread surface and the shoulder portion of the tire T are moved in the Z-axis direction by driving the eccentric displacement motor 26. The eccentric rigidity in the tire radial direction can be obtained from the amount of displacement of the tire T in the Z-axis direction at this time and the force in the Z-axis direction applied to the tire T measured by the tire force load cell 12.

  Further, the tire support shaft 11 is moved in the Y-axis direction by driving the lateral displacement motor 15. The lateral rigidity in the tire width direction can be obtained from the amount of displacement of the tire T in the Y-axis direction at this time and the force in the Y-axis direction applied to the tire T measured by the tire force load cell 12.

  Further, the tire support shaft 11 is rotated by driving the in-plane torsion motor 13. The in-plane torsional rigidity in the tire rotation direction can be obtained from the torsion angle of the tire T around the Y axis and the torque around the Y axis acting on the tire T measured by the tire force load cell 12.

  Further, the frame 16 is moved in the Z-axis direction by driving the out-of-plane torsion motor 17. Thus, the tire support shaft 11 can be rotated about the X axis. The out-of-plane torsional rigidity around the axis orthogonal to the tire rotation axis is obtained from the twist angle around the X axis of the tire T and the torque around the X axis acting on the tire T measured by the tire force load cell 12. be able to.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. The rigidity (in-plane torsional stiffness, out-of-plane torsional stiffness, eccentric stiffness, lateral stiffness) was measured using a tire having a tire size of 215 / 45R17 87W. In addition, a state in which the tread portion and the shoulder portion are at rest by simulation is obtained as an ideal restraint state is used as a reference example, and the index when the rigidity in the reference example is 100 is shown. Only the rigidity of the side part can be measured accurately. The measurement results of the stiffness are shown in Table 1.

Example An example was obtained by measuring the stiffness of a tire using the stiffness measurement apparatus and the stiffness measurement method of the present invention.

Comparative Example A comparative example was obtained by measuring the rigidity of a tire which had no shoulder clamp and was restrained only by the center clamp.

  As shown in Table 1, the rigidity of the side portion could be accurately measured by restraining the shoulder portion with the shoulder clamp.

DESCRIPTION OF SYMBOLS 1 Tire support part 2 Tire restraint part 11 Tire support shaft 21 Center clamp 22 Shoulder clamp T Tire

Claims (3)

A tire support shaft to which a tire is attached at the tip;
A plurality of center clamps arranged at equal intervals in the tire circumferential direction and constraining the tread surface of the tire attached to the tire support shaft in the tire radial direction;
The shoulder portions of the tire in which the tread surface is restrained by the center clamp are arranged in the tire width direction by being disposed on both sides in the tire width direction of the center clamp and moving in the tire width direction along the outer surface of the center clamp. A shoulder clamp to restrain to,
And a stiffness measuring means for measuring the stiffness of the tire by deforming the tire by relatively displacing the tread surface restrained with the tire support shaft and the shoulder portion.   2. The tire according to claim 1, wherein the shoulder portion pressing surface of the shoulder clamp that presses the shoulder portion of the tire has a height from the outer surface of the center clamp in the tire width direction center of 10 to 30 mm. Stiffness measuring device. Attaching the tire to the tip of the tire support shaft;
With respect to the tire attached to the tire support shaft, the tread surface is restrained in the tire radial direction by a plurality of center clamps arranged at equal intervals in the tire circumferential direction, and disposed on both sides of the center clamp in the tire width direction A step of restraining the shoulder portion in the tire width direction with the shoulder clamp made,
Measuring the rigidity of the tire by deforming the tire by relatively displacing the tread surface restrained with the tire support shaft and the shoulder portion ;
The tread surface is restrained by moving the center clamp closer to the tread surface from the outer peripheral side and moving the tire clamp inward until the reaction force from the tread surface becomes a first predetermined value,
After restraining the tread surface, the shoulder clamp is made to approach the shoulder portion from the outside in the tire width direction, and is moved inward in the tire width direction until the reaction force from the shoulder portion becomes a second predetermined value. A method for measuring the rigidity of a tire, characterized in that the shoulder portion is restrained .

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