Strain amount detecting device, tire

Abstract

The present application aims to provide a strain amount detection device capable of highly accurately detecting deformation of a tire in a plurality of directions by one strain measurement element. The strain amount detection device of the present application includes a base member of a circular plate shape for holding a strain measurement element, which serves as a strain body by transmitting a strain of a tire to the strain measurement element (see FIG. 4).

Description

Technical Field

[0001] This invention relates to a strain detection device for detecting strain in tires. Background Technology

[0002] A tire strain measuring element is known as a sensor for acquiring the state of the tires mounted on a vehicle. The tire strain measuring element is, for example, mounted on the inner surface of the tire and converts the strain of the component that occurs alongside the tire strain into an electrical signal and outputs it.

[0003] Patent Document 1 describes a component mounted on the inner circumferential surface of a tire to obtain the tire's state. The document addresses the problem of "providing a functional component that, when mounted onto a tire, sufficiently ensures the thickness of the adhesive and improves the adhesive strength," and describes a technology comprising: "a functional component that houses an electronic component capable of acquiring information within the tire and is mounted on the inner circumferential surface of the tire, the functional component being configured to include: a housing portion for the electronic component; a housing having a bottom surface opposite to the inner circumferential surface of the tire; and a cylindrical portion extending from the periphery of the bottom surface toward the inner circumferential surface." (See abstract).

[0004] The following patent document 2, titled "Provides a strain measurement structure and strain measurement method that facilitates accurate measurement of the strain of reinforcing fibers in fiber-reinforced synthetic rubber," describes a method where "the belt layer cord 20 is a reinforcing fiber extending in a certain direction inside a synthetic rubber composed of tread rubber 12A and top rubber 22. Holes 24 are formed in the synthetic rubber to expose a portion of the belt layer cord 20 to the outside of the synthetic rubber. A strain gauge mounting base 26 is mounted at the bottom of the hole 24 on the portion where the belt layer cord 20 is exposed. The Young's modulus of the strain gauge mounting base 26 is more than 10 times that of the synthetic rubber and less than 1 / 10 of the Young's modulus of the belt layer cord 20. A strain gauge 28 is mounted on the portion of the strain gauge mounting base 26 located on the opposite side of the belt layer cord 20. Holes 24 are embedded with embedding material 32. The strain of the belt layer cord is measured by the strain gauge 28." (See abstract). Existing technical documents Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-055402 Patent Document 2: Japanese Patent Application Publication No. 2011-242279 Summary of the Invention The technical problem that the invention aims to solve

[0006] When a vehicle turns, the direction of tire deformation changes with the turning state and direction. When the detection axis of the strain gauge and the tire's deformation direction are not aligned, strain measurement accuracy decreases. Therefore, strain gauges need to be placed in each direction of tire deformation detection. If multiple directions of deformation need to be detected using a single strain gauge, to improve detection accuracy, the tire's deformation direction and amount need to be accurately transmitted to the components of the strain gauge.

[0007] In Patent Document 1, a strain sensor 68 is mounted on the bottom surface of a housing 2, and the housing 2 and the inner surface of the tire 10 are bonded together using adhesive B, so that the strain sensor 68 and the inner surface of the tire 10 are in direct contact. According to 0049 of that document, it is preferable to make the strain sensor 68 in direct contact with the inner surface of the tire in this manner for strain measurement. However, according to paragraphs 0049-0051 of that document, since the strain of the tire 10 is greater than the measurable range of the strain sensor 68, it is difficult to perform a proper measurement in this situation. Therefore, in this document, adhesive B adjusts the measurement range by mitigating its strain.

[0008] In the structure described in Patent Document 1, the strain of the tire 10 is transmitted to the strain sensor 68 via the adhesive B. The adhesive B does not necessarily deform in the same direction as the deformation of the tire 10, but may deform irregularly. This is because the planar shape of the adhesive B is not necessarily isotropic within the bonding surface, and may be an irregular shape. Therefore, in this document, it can be assumed that the detection accuracy for deformation in directions other than the axial direction may be reduced.

[0009] In Patent Document 2, a hole 24 is provided on the tire surface, and a strain gauge 28 is mounted in the hole 24 via a base 26. Since the purpose of this document is to measure the strain of the tire's reinforcing fibers, the strain of the reinforcing fibers must be transmitted to the strain gauge 28. Therefore, in this document, the Young's modulus of the base 26 is made less than 1 / 10 of the Young's modulus of the belt layer cord 20 (reinforcing fiber), and the base 26 is only used as a relay member to transmit the strain of the reinforcing fibers to the strain gauge 28 as is. That is, in this document, there is no component equivalent to the strain body of the strain gauge 28. Since the base 26 is a flexible component, it may not deform isotropically in response to the deformation of the reinforcing fibers, but rather irregularly. Therefore, it can be considered to have the same problem as Patent Document 1.

[0010] The present invention was made in view of the above-mentioned problems, and its object is to provide a strain detection device that can detect the deformation of a tire in multiple directions with high precision by means of a strain measuring element. Technical means for solving technical problems

[0011] The strain detection device of the present invention includes a base member for maintaining the circular plate shape of the strain measuring element, the base member serving as a strain variable by transferring the strain of a tire to the strain measuring element. Invention Effects

[0012] According to the strain detection device of the present invention, the deformation of a tire in multiple directions can be detected with high precision using a single strain measuring element. Attached Figure Description

[0013] Figure 1 This is a diagram illustrating the tire slip angle. Figure 2 It is a graph illustrating the relationship between the tire slip angle and tire strain. Figure 3 This is a side view showing the structure of the strain detection device 1 according to Embodiment 1. Figure 4 This is a top view of the base component 13. Figure 5 This is a cross-sectional view showing the interior of tire 2. Figure 6 This is a top view of the base component 13 of the strain detection device 1 in Embodiment 2. Figure 7 This is a top view showing a modified example of the base member 13 in Embodiment 2. Figure 8 This is a top view of the base component 13 of the strain detection device 1 in Embodiment 3. Detailed Implementation

[0014] <Regarding tire strain> The following section first describes an example of a cause of tire deformation and the usefulness of detecting such a condition. Next, an example of the structure of the strain detection device according to an embodiment of the present invention will be described.

[0015] Figure 1 This is a diagram illustrating the tire slip angle. The tires on a vehicle are typically oriented in the same direction as the vehicle's travel. Figure 1 In the middle, all tires are usually oriented towards Figure 1 The vertical direction. However, if the tires slip, the vehicle's direction of travel and the tires' orientation will deviate, sometimes resulting in... Figure 1 The slip angle shown.

[0016] Figure 2 It is a graph illustrating the relationship between the tire slip angle and tire strain. Figure 2 The left side is a side view of the tire. Figure 2The right side is a top view of the tire showing deformation. The direction of the force acting on the tire to deform varies depending on the tire's slip angle. For example, when the slip angle is 4°, the force causes the tire to... Figure 2 The force that causes deformation in the approximate lower right direction plays a role.

[0017] Therefore, there is a corresponding relationship between the direction and amount of tire strain deformation and the slip angle. Thus, by understanding the direction and amount of tire deformation, such as during vehicle cornering, compared to normal driving conditions, it is possible to detect signs of slippage or tire spinning. This allows for driver alertness or more advanced vehicle control, thereby improving vehicle safety.

[0018] <Implementation Method 1> Figure 3 This is a side view showing the structure of the strain detection device 1 according to Embodiment 1 of the present invention. The strain detection device 1 is mounted on the inner surface of the tire 2 and detects the strain of the tire 2. The strain detection device 1 includes a strain measuring element 11, a wafer bonding member 12, and a base member 13. One surface of the base member 13 is fixed to the inner surface of the tire 2 by an adhesive 15. The strain measuring element 11 is mounted on the other surface of the base member 13 via the wafer bonding member 12.

[0019] The strain measuring element 11 is, for example, a strain gauge. In the strain gauge, the strain measuring element 11 itself deforms due to the deformation of the strained material, and an electrical signal corresponding to the strain is output through the change in resistance accompanying the strain. The wafer adhesive 12 is an adhesive used to fix the strain measuring element 11 to the surface of the base member 13. The strain measuring element 11 and the wafer adhesive 12 are sealed to the surface of the base member 13 by a sealing material 14 (e.g., resin).

[0020] If the tire 2 deforms, the base member 13 itself also deforms along with the deformation, and the strain is transferred to the strain measuring element 11 via the adhesive 15. That is, the base member 13 serves as the strain of the strain measuring element 11. The base member 13 is made of a material that can be fixed to the inner surface of the tire 2 at least via the adhesive 15 and can transfer the strain of the tire 2 to the strain measuring element 11 via the adhesive 15.

[0021] Figure 4 This is a top view of the base component 13. The x-axis and y-axis are the detection axes of the strain measuring element 11 for detecting strain. That is, the strain measuring element 11 can measure the strain in the x-axis direction and the strain in the y-axis direction.

[0022] The base member 13 is configured relative to the action on Figure 4The forces in at least two directions on the xy plane deform equally. Preferably, the base member 13 has a circular plate shape. If the base member 13 has a circular plate shape, it can... Figure 4 Forces in any direction on the xy plane can be accurately decomposed into x-components and y-components. For example, Figure 4 εc can be expressed as εc=(εx) 2 +εy 2 ) 1 / 2 Therefore, the direction and strain of strain in any direction on the xy plane can be measured as a vector using a strain measuring element 11.

[0023] To accurately measure strain in any direction in the xy-plane using a strain measuring element 11, the center of the strain measuring element 11 in the xy-plane (the origin of the two measuring axes) is preferably aligned with the center of the base member 13 in the xy-plane. This allows for uniform detection of strain in any direction in the xy-plane. However, slight deviations in the center position are not entirely unacceptable; for example, depending on the installation configuration, the centers may deviate slightly. In such cases, the strain measured by the strain measuring element 11 can be calculated and corrected based on this deviation.

[0024] Figure 5 This is a cross-sectional view showing the interior of tire 2. The view is shown from either the front or rear of the vehicle. The strain detection device 1 is preferably positioned near the center of the tire in the width direction (orthogonal to the vehicle's longitudinal direction), and preferably the center of the tire in the width direction coincides with the center of the strain detection device 1 in the width direction. This means that the strain detection device 1 is positioned at the center of the tire's contact patch. Therefore, since the deformation direction of the tire and the strain direction of the base member 13 are aligned, the accuracy of tire strain detection can be improved.

[0025] <Implementation Method 1: Summary> In the strain detection device 1 of this embodiment 1, the strain measuring element 11 is disposed on a circular plate-shaped base member 13, and the base member 13 serves as the strain volume of the strain measuring element 11. Thus, the base member 13 can uniformly transmit strain in any direction within the circular plate surface (xy plane) to the strain measuring element 11. Therefore, strain in any direction within the xy plane can be detected by a single strain measuring element 11.

[0026] <Implementation Method 2> Figure 6This is a top view of the base member 13 included in the strain detection device 1 according to Embodiment 2 of the present invention. In this embodiment, the base member 13 has a cutout 131 in its circumferential portion. The cutout 131 is, for example, an annular sector (a sector formed by an outer large-diameter arc and an inner small-diameter arc). The number of cutouts 131 is arbitrary.

[0027] like Figure 6 As shown, since the base member 13 has a cutout 131, the portion with the cutout 131 (from the center of the base member 13 toward the cutout 131, for example...) Figure 6 The strain detection accuracy in the 45° direction is lower than that in the part without notch 131 (from the center of the base member 13 toward the position where no notch 131 is formed, for example...). Figure 6 The strain detection accuracy is improved in the 90° direction (within the model). This is because the amount of strain transmitted by the component is relatively small. Therefore, the strain detection accuracy in a specific direction can be highlighted. Figure 6 In this process, the detection accuracy in the 90°, 180°, 270°, and 360° directions increases. For example, in the case of high-precision detection of strain in a specific direction when a vehicle is turning, Figure 6 The structure shown is useful.

[0028] Figure 7 This is a top view showing a modified example of the base member 13 in Embodiment 2. Figure 6 In the middle, the notch 131 is configured to increase the detection accuracy in the xy-axis direction, while Figure 7 In this configuration, the notch 131 is set to reduce the detection accuracy in the xy-axis direction. Figure 7 In the process, the detection accuracy increases in the 45°, 135°, 225°, and 315° directions.

[0029] <Implementation Method 3> Figure 8 This is a top view of the base component 13 of the strain detection device 1 according to Embodiment 3 of the present invention. In this embodiment, the base member 13 has a protrusion that projects radially outward from a portion of its circumference. The thickness, number, and direction of the protrusion are arbitrary. Figure 8 The image shows examples of slightly thicker protrusions pointing in the 90°, 180°, 270°, and 360° directions, respectively.

[0030] The strain detection accuracy in the direction without the protrusion is lower than that in the direction with the protrusion. The reason is the same as when the detection accuracy is reduced due to the cut 131. Therefore, similar to Embodiment 2, the strain detection accuracy in a specific direction can be improved.

[0031] <Regarding variations of the present invention> Furthermore, the present invention is not limited to the embodiments described above, and includes various modifications. For example, the above-described embodiments are detailed for ease of understanding and illustration of the present invention, and the present invention is not necessarily limited to including all the structures described. Additionally, a portion of the structure of one embodiment may be replaced with a structure of another embodiment; conversely, a structure of another embodiment may be added to the structure of one embodiment. Furthermore, a portion of the structure in each embodiment may be added to, deleted from, or replaced with other structures.

[0032] While the above embodiments illustrate an example of detecting tire strain by mounting the strain detection device 1 on the tire, the present invention is also applicable to detecting strain in objects other than tires. That is, the present invention is useful in methods that uniformly detect deformation in any direction on the xy plane by making the base member 13 have a circular plate shape. Label Explanation

[0033] 1: Strain detection device 11: Strain Measurement Element 12: Chip bonding components 13: Base components 14: Sealing materials 15: Adhesive 2: Tires.

Claims

1. A strain detection device for detecting the strain of a tire, characterized in that it comprises: A strain measuring element used to detect the strain of a strained body; as well as A base component for holding the strain measuring element. The base component has a circular plate shape. The base component serves as the strain gauge by transferring the strain of the inner wall surface of the tire to the strain measuring element. By having a notch on the circumferential portion of the circular plate shape, the strain measuring element is configured such that the strain detection accuracy in a second direction from the center of the strain measuring element toward the direction where the notch is not formed is higher than the strain detection accuracy in a first direction from the center of the strain measuring element toward the notch.

2. A strain detection device for detecting the strain of a tire, characterized in that it comprises: A strain measuring element used to detect the strain of a strained body; as well as A base component for holding the strain measuring element. The base component has a circular plate shape. The base component serves as the strain gauge by transferring the strain of the inner wall surface of the tire to the strain measuring element. The strain measuring element has a radially projecting protrusion in a portion of the circumferential portion of the circular plate shape, and the strain measuring element is configured such that the strain detection accuracy in a second direction from the center of the strain measuring element toward the direction in which the protrusion is not formed is lower than the strain detection accuracy in a first direction from the center of the strain measuring element toward the protrusion.

3. The strain detection device as described in claim 1 or 2, characterized in that, The strain measuring element is positioned at the center of one face of the circular plate shape of the base member.

4. The strain detection device as described in claim 1 or 2, characterized in that, The strain measuring element is configured to detect the strain of the strain body along a first direction and to detect the strain of the strain body along a second direction different from the first direction.

5. The strain detection device as described in claim 1 or 2, characterized in that, The strain measuring element is fixed to one surface of the circular plate shape by an adhesive.

6. A tire, characterized in that, Having the strain detection device as described in claim 1 or 2, One surface of the circular plate forming the base member is connected to the inner wall surface of the tire by an elastic adhesive, thereby the base member transmits the strain of the tire to the strain measuring element.

7. The tire as described in claim 6, characterized in that, The base member is disposed at or near the center of the tire in the width direction.

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