Apparatus and method for simulating tire behavior in plunger testing

Abstract

Provide an apparatus and method for simulating the behavior of a tire in a plunger test. **Solution**: An apparatus for simulating the behavior of a tire in a plunger test, comprising a grounding plate suitable for being firmly fixed to a tire support hub of a plunger testing machine, a support plate movably connected to the grounding plate by damping means, and only displacement along a preferred movement axis being permitted by the damping means, a pneumatic or hydraulic actuator connected to the support plate and suitable for being filled with a compressed fluid during operation and comprising an actuator piston, an actuating means connected to the grounding plate and suitable for causing the discharge of the compressed fluid in a pneumatic or hydraulic cylinder during operation, and a switching means connected to the support plate and suitable for engaging with the actuating means when the support plate is displaced, wherein the support plate is suitable for moving along the preferred movement axis when displacement is applied to the actuator rod.

Description

【Technical Field】 【0001】 The present invention relates to an apparatus and a method for simulating the physical behavior during a test as an alternative to a tire in a tire strength test. 【Background Art】 【0002】 A tire strength test or "plunger test" is one of several mandatory test requirements that a tire must meet according to the regulations of a particular country in order to obtain the necessary government certification to release the tire to the market. 【0003】 The Federal Motor Vehicle Safety Standard (FMVSS) 139 in the United States is an example of such a regulation. 【0004】 In a tire strength test or "plunger test", the force applied through a plunger rod at the center of the tread width of the tire and the amount of displacement due to the deformation of the tire are measured by a tire strength tester or a plunger tester until the tire bursts and breaks by the plunger rod. 【0005】 The energy at the breaking point required to break the tire is calculated by the formula "Energy = Force × Displacement ÷ 2" defined by the regulations. 【0006】 The tire passes or fails the tire strength test or "plunger test" according to the energy required to break the tire. 【0007】 As is immediately apparent, the tire strength test or "plunger test" is a destructive test, and at the end of the test, the tire must be destroyed by bursting and discarded, so it cannot be used anymore or used a second time. 【0008】 This becomes a drawback when it is necessary to associate different test apparatuses (and their test results) with each other or when it is necessary to monitor the stability of the performance of the same apparatus. 【0009】 Therefore, in this type of testing, there is a growing need to find alternative methods that can repeatedly and comprehendably reproduce the same tire behavior over time using different equipment, rather than using actual tires. 【0010】 Patent Document 1 discloses a tire tread strength and bead deviation testing apparatus, and more specifically, discloses a technology that allows tire tread strength testing and bead tread testing to be performed simultaneously on a single testing machine while automatically measuring the load and displacement of the test subject. [Prior art documents] [Patent Documents] 【0011】 [Patent Document 1] KR20120092965A [Overview of the project] [Problems that the invention aims to solve] 【0012】 The present invention provides a device for simulating the behavior of a tire in a plunger test, which is free from the aforementioned drawbacks of the prior art and, in particular, can be easily and inexpensively implemented. 【0013】 The present invention further provides a method for simulating the behavior of a tire in a plunger test that is free from the aforementioned drawbacks of the prior art and, in particular, can be easily and inexpensively implemented. [Means for solving the problem] 【0014】 According to the present invention, an apparatus for simulating the behavior of a tire in a plunger test and a method for simulating the behavior of a tire in a plunger test are provided, as described in the appended claims. 【0015】 This device includes a grounding plate suitable for being firmly fixed to a plunger testing machine, a support plate movably connected to the grounding plate by damping means, a pneumatic or hydraulic actuator connected to the support plate and equipped with an actuator piston, operating means suitable for causing the discharge of the pneumatic or hydraulic cylinder, and switching means suitable for engaging with the operating means when the support plate is displaced. 【0016】 This device may further include guide means connected to the grounding plate for guiding the support plate when the support plate is displaced. 【0017】 This device may further include a displacement meter suitable for measuring the relative displacement between the grounding plate and the support plate. 【0018】 The grounding plate is suitable for being firmly fixed to the tire support hub of the plunger testing machine. 【0019】 The grounding plate is preferably fixed to the tire support hub of the plunger testing machine via fixing means. 【0020】 The damping means for connecting the support plate to the grounding plate allows only displacement along the preferred movement axis. 【0021】 The support plate is suitable for moving along the preferred movement axis when displacement is applied to the actuator piston. 【0022】 The grounding plate and the support plate preferably have the same shape, dimensions, and surface area. 【0023】 The pneumatic or hydraulic actuator connected to the support plate is suitable for being filled with compressed fluid during operation. 【0024】 The pneumatic or hydraulic actuator is a pneumatic cylinder. 【0025】 The operating means may be connected to the grounding plate. The operating means may be firmly connected to the grounding plate. 【0026】 The actuating means is suitable for causing the discharge of the compressed fluid in the pneumatic or hydraulic cylinder when it operates. 【0027】 The actuating means may be a mechanical actuating means (e.g., a lever) or an optical actuating means (e.g., a photocell). 【0028】 The switching means may be connected to the support plate. 【0029】 This device may further include a positioning rod. The positioning rod can be connected to the grounding plate. The actuating means can be connected to the grounding plate via the positioning rod. The positioning rod is suitable for positioning the actuating means at different positions along the preferred movement axis. 【0030】 The damping means includes at least a spring. 【0031】 The damping means is preferably symmetrically arranged on the surfaces of the grounding plate and the support plate. 【0032】 The grounding plate and the support plate are preferably rectangular. 【0033】 The damping means is preferably dispersedly arranged at two locations on the distal sides of the surfaces of the grounding plate and the support plate. 【0034】 The present invention will be described with reference to the accompanying drawings showing some non-limiting exemplary embodiments. 【Brief Description of the Drawings】 【0035】 [Figure 1] It is a perspective view of a device for simulating the behavior of a tire in a plunger test. [Figure 2] It is a front view of the device of FIG. 1. [Figure 3] It is a front view of the device in a state where the actuator piston is pulled out and in contact with the plunger of the plunger tester. [Figure 4] This is a perspective view of the device in a state where the actuator piston is in the extended position, the plunger is in the displacement position during testing, and the switching mechanism is engaged with the actuating mechanism. [Figure 5] Figure 4 is a side view of the apparatus. [Figure 6] This figure shows the details of how the switching mechanism engages with the operating mechanism. [Figure 7] This diagram illustrates the force / displacement graphs for two actual tires and a device, respectively. [Modes for carrying out the invention] 【0036】 In Figure 1, reference numeral 1 denotes the overall apparatus for simulating the behavior of a tire in a plunger test (also called a plunger test simulator tool). 【0037】 Apparatus 1 includes a ground plate 2 that is firmly fixed to the tire support hub 50 of the plunger testing machine 100 (schematic diagram only) via fixing means 13. The fixing means 13 is preferably an elongated rod that passes under the tire support hub 50 and is preferably fixed to the ground plate 2 via screws, thereby fixing the tire support hub 50 between the ground plate 2 and the elongated rod. 【0038】 To ensure measurement accuracy, it is important to firmly fix the contact plate 2 of the device 1 to the tire support hub 50 of the plunger testing machine 100 and to suppress any movement of the contact plate 2. 【0039】 The device 1 further includes a support plate 3 that is movably connected to the ground plate 2 by a damping means 4. 【0040】 The damping means 4 extends from the upper surface of the ground plate 2 to the lower surface of the support plate 3. 【0041】 The upper surface of the contact plate 2 and the lower surface of the support plate 3 are parallel to each other. 【0042】 The support plate 3 is supported by the damping means 4. 【0043】 The damping means 4 preferably includes at least a spring. 【0044】 The damping means 4 preferably comprises a plurality of springs. 【0045】 In addition to supporting the support plate 3, the damping means 4 has the function of reproducing the vertical rigidity of an actual tire. 【0046】 To reproduce real tires of different sizes, or more generally, tires of different categories (passenger car tires, commercial van tires, truck tires, etc.), and different air pressure conditions, specific calibration of the damping means 4 is required. 【0047】 As shown in Figure 7, the displacement of the plunger 10 due to the force applied to the tire is plotted during the plunger test. The average slope of the resulting graph represents the vertical stiffness of the tire and its spring constant k. 【0048】 In Figure 7, the solid line represents the results of a plunger test using a device to simulate tire behavior in a plunger test, the dashed line represents the results for an actual tire of size 265 / 30R21 with a spring constant of approximately 10.5 kg / mm, and the dotted line represents the results for an actual tire of size 265 / 30R21 with a spring constant of approximately 7.5 kg / mm. The air pressure of both tires was set to 2.0 bar. The spring constant of damping means 4 is approximately 8.9 kg / mm. 【0049】 Calibration of damping means 4 means that the sum of the spring constants of damping means 4 represents the range of spring constants for a specific tire type. 【0050】 The table below shows the expected range of spring constants for different categories of tires. 【0051】 [Table 1] 【0052】 The damping means 4 should be calibrated and selected so as to be able to represent the vertical stiffness of the tire category, i.e., the spring constant. 【0053】 If the specific tire size and specifications are known, it is possible to accurately reproduce the spring constant of that tire. 【0054】 In a preferred embodiment, the damping means 4 consists of 12 single springs. The spring constant k of the damping means 4 T Assuming the total is 8.9 kg / mm, in the embodiments shown in Figures 1 to 5, since the springs of the damping means 4 are in a parallel configuration, the spring constant k of each spring is S It is 0.74 kg / mm³. 【0055】 The damping means 4 is arranged symmetrically on the upper surface of the ground plate 2 and the lower surface of the support plate 3 in order to uniformly distribute the load on the support plate and the load applied during the plunger test. 【0056】 By arranging the damping means 4 symmetrically, it becomes possible to maintain parallelism between the upper surface of the ground plate 2 and the lower surface of the support plate 3 while the support plate 2 is being displaced. 【0057】 Preferably, the grounding plate 2 and the support plate 3 are rectangular and have the same dimensions. That is, the upper surface of the grounding plate 2 and the lower surface of the support plate 3 have the same surface area. 【0058】 Preferably, the damping means 4 are distributed at two locations on the distal side of the upper surface of the grounding plate and the lower surface of the support plate. 【0059】 The damping means 4 connecting the support plate 3 to the ground plate 2 preferably allows displacement only along a preferred movement axis. The preferred movement axis is perpendicular to both the upper surface of the ground plate 2 and the lower surface of the support plate 3. 【0060】 To ensure that the displacement of the support plate 3 occurs only along the preferred axis of movement, the device 1 preferably includes a guide means 9. 【0061】 The guide means 9 extends in the direction of the preferred movement axis and is fixedly connected to the ground plate 2. 【0062】 The guide means 9 is preferably a rod or shaft with a circular cross-section. 【0063】 Preferably, the device 1 includes the same number of guide means 9 as damping means 4. 【0064】 Preferably, the guide means 9 and the damping means 4 are coaxial, that is, each element of the guide means 9 is coaxial with a single element of the damping means 4. 【0065】 Preferably, the guide means 9 are positioned axially inward of the damping means 4, in other words, each element of the damping means 4 surrounds an element of the guide means 9. 【0066】 The support plate 3 has at least one through hole, the dimensions of which are such that the guide means 9 can pass through, but the damping means 4 cannot. 【0067】 The guide means 9 includes a limiting element 14 located at its distal end from the ground plate 2. The limiting element 14 is located at the end of the guide means 9 that passes through a through hole in the support plate 3. The limiting element 14 is positioned on the side of the support plate 3 opposite to the damping means 4. 【0068】 The limiting element 14 has, firstly, the function of fixing the support plate 3 to the guide means 9, more precisely, the function of fixing the support plate 3 so that it does not move beyond the guide means 9, and secondly, the function of adjusting the initial compression of the damping means 4. 【0069】 The initial compression of the damping means 4 refers to the compression of the spring when no force is applied to the device 1 via the plunger 10. 【0070】 The limiting element 14 preferably comprises a ring and a bolt. 【0071】 The limiting element 14 is preferably connected to the guide means 9 via a screw. 【0072】 The device 1 further includes a pneumatic or hydraulic actuator 5 that is firmly connected to the support plate 3. 【0073】 The pneumatic or hydraulic actuator 5 includes an actuator piston 6. 【0074】 The pneumatic or hydraulic actuator 5 is preferably a pneumatic or hydraulic cylinder. 【0075】 The pneumatic or hydraulic actuator 5 is suitable for being filled with compressed fluid during operation. When the pneumatic or hydraulic actuator 5 is filled with compressed fluid, it moves the actuator piston 6 to the extended position, as shown in Figure 3. 【0076】 Conversely, when compressed fluid is discharged from the pneumatic or hydraulic actuator 5, the actuator piston 6 retracts to the retracted position as shown in Figure 1 or 2. 【0077】 The movement axis T of the actuator piston 6 is parallel to the preferred movement axis. 【0078】 The device 1 further comprises an actuation means 7 suitable for causing discharge of a pneumatic cylinder or a hydraulic cylinder 5. 【0079】 When the actuation means 7 is engaged or actuated, it prompts the pneumatic or hydraulic actuator 5 to discharge the compressed fluid, thereby simulating tire failure. 【0080】 The actuation means 7 is preferably a mechanical actuation means 7 (e.g., a lever) or an optical actuation means 7 (e.g., a photocell). 【0081】 The operating means 7 is preferably connected to the grounding plate 2. 【0082】 The device 1 may further include a positioning rod 11. The positioning rod is preferably connected to the grounding plate 2. 【0083】 The operating means 7 is preferably connected to the ground plate via the positioning rod 11. 【0084】 The positioning rod 11 is suitable for positioning the actuation means 7 at different positions or heights along the preferred movement axis T. 【0085】 The device 1 further comprises a switching means 8 suitable for engaging with the operating means 7. 【0086】 The switching means 8 is preferably connected to the support plate 3. 【0087】 The switching means 8 is suitable for engaging with the operating means 7 when the support plate 3 is in a predetermined displacement. 【0088】 The switching means 8 is configured to engage with the actuation means 7 to simulate tire failure. 【0089】 The switching means 8 is configured to engage with the operating means 7 when the support plate 3 is displaced by a predetermined amount along its displacement 3. 【0090】 The predetermined displacement of the support plate 3 corresponds to the displacement required to enable the switching means 8 to engage with the operating means 7. 【0091】 By positioning the actuation means 7 at different locations or heights, the switching means 8 can engage with the actuation means 7, and as a result, the device 1 can select a predetermined amount of displacement of the support plate 3 that simulates tire failure. 【0092】 The apparatus 1 may further include a displacement meter 16 for measuring the amount of displacement between the ground plate 2 and the support plate 3 during the plunger test. 【0093】 The device 1 may further include a load cell 17 (not shown) located between the actuator piston 6 and the plunger 10 at the outer end of the actuator piston 6. 【0094】 The load cell 17 is suitable for measuring the force applied to the device 1 that simulates the behavior of a tire during a plunger test. 【0095】 A method for calculating the energy required to destroy a tire during a plunger test can be obtained by measuring the applied force using the load cell 17 and the displacement between the contact plate 2 and the support plate 3. 【0096】 The measurement of force and displacement by the load cell 17 and displacement meter 16 provides comparative data in addition to, or instead of, the measurement data from the plunger testing machine itself. The additional comparative data set can also be used to verify the proper functioning of the plunger testing machine. 【0097】 During operation, the device 1 is mounted on the tire support hub 50 of the plunger testing machine 100, and the pneumatic or hydraulic actuator 5 is filled with compressed fluid, which moves the actuator piston 6 to the extended position. Before starting the plunger test, the plunger 10 of the plunger testing machine 100 is pressed against the actuator piston 6, as shown in Figure 3. 【0098】 During the plunger test procedure, force is applied to the plunger 10 of the test machine, resulting in displacement of the actuator piston 6 and the pneumatic or hydraulic actuator 5, as shown in Figures 4 and 5. 【0099】 Since the pneumatic or hydraulic actuator 5 is firmly connected to the support plate 3, the support plate 3 is pushed downward, that is, towards the ground plate 2 along the preferred axis of movement. 【0100】 This compresses the damping means 4. 【0101】 A switching mechanism 8 located on the support plate 3 engages with the operating mechanism 7 at a predetermined height (see Figures 5 and 6), which causes compressed fluid to be discharged from the pneumatic or hydraulic actuator 5, simulating tire failure. 【0102】 The present invention also provides a method for simulating the behavior of a tire during a plunger test. 【0103】 This method includes using device 1 instead of an actual tire during the plunger test. 【0104】 The method includes the steps of: attaching the device 1 to the tire support hub 50 of the plunger testing machine 100; filling the pneumatic or hydraulic actuator 5 with compressed fluid, thereby moving the actuator piston 6 to the extended position; pushing the plunger 10 of the plunger testing machine 10 against the actuator piston 6; applying force to the plunger 10 to start the plunger test; and displacing the support plate 3 with the force applied to the actuator piston 6 until the switching means 8 engages with the actuation means 7, thereby causing compressed fluid to be discharged from the pneumatic or hydraulic actuator 5 and simulating tire damage. 【0105】 This method may further include the steps of: placing a load cell 17 between the actuator piston 6 and the plunger 10; measuring the applied force and the displacement between the contact plate 2 and the support plate 3 during the test; and calculating the energy at the point in time when a simulation of tire failure occurs. [Explanation of symbols] 【0106】 1 device 2 Ground plate 3 Support plate 4. Damping means 5. Pneumatic or hydraulic actuators 6 Actuator Piston 7. Operating means 8 Switching means 9. Guiding means 10 plungers 11 Positioning rod 13 Fixing means 14 Limiting Factors 15 Tire support hub 16 Displacement gauge 17 Load Cells 100 Plunger Testing Machine T Preferred movement axis

Claims

[Claim 1] A device for simulating the behavior of a tire in a plunger test, A grounding plate suitable for firmly fixing to the tire support hub of a plunger testing machine, A support plate movably connected to the ground plate by a damping means, wherein the damping means is permitted to be displaced only along a suitable movement axis perpendicular to both the upper surface of the ground plate and the lower surface of the support plate, A pneumatic or hydraulic actuator, connected to the aforementioned support plate, suitable for being filled with compressed fluid during operation, and equipped with an actuator piston, An actuation means connected to the ground plate and suitable for causing the discharge of the compressed fluid in the pneumatic or hydraulic actuator when in operation, The system includes a switching means connected to the support plate and suitable for engaging with the operating means when the support plate is displaced to a predetermined extent, The support plate is suitable for moving along the preferred moving axis when force is applied to the actuator piston. [Claim 2] The apparatus according to claim 1, further comprising a positioning rod connected to the grounding plate, wherein the actuation means is connected to the grounding plate via the positioning rod, and the positioning rod is suitable for positioning the actuation means at different positions along the preferred movement axis. [Claim 3] The apparatus according to claim 1, wherein the damping means comprises at least a spring. [Claim 4] The apparatus according to claim 1, wherein the damping means is symmetrically arranged on the surfaces of the ground plate and the support plate. [Claim 5] The apparatus according to claim 4, wherein the damping means are dispersed at two locations on the distal side of the surface of the ground plate and the support plate. [Claim 6] The apparatus according to claim 1, wherein the pneumatic or hydraulic actuator is a pneumatic cylinder. [Claim 7] The apparatus according to claim 1, further comprising a displacement meter for measuring the amount of displacement of the support plate relative to the ground plate. [Claim 8] The apparatus according to claim 1, further comprising a load cell connected to the actuator piston for measuring the force applied to the actuator piston. [Claim 9] The apparatus according to claim 1, wherein the damping means has a spring constant in any one range of 5 to 12 kg / mm, 13 to 22 kg / mm, or 30 to 50 kg / mm. [Claim 10] A method for performing a plunger test with a plunger testing machine using the apparatus described in any one of claims 1 to 9, The steps include fixing the device to the support hub of the plunger testing machine, The steps include filling the aforementioned pneumatic or hydraulic actuator with fluid, thereby raising the actuator rod toward the plunger of the plunger testing machine, The steps include: starting the plunger test by applying force to the actuator piston via the plunger and displacing the support plate along the preferred movement axis; A method comprising the step of ending the test when the switching means engages with the operating means due to the displacement of the support plate. [Claim 11] The steps include measuring the amount of displacement of the support plate via a displacement sensor, The steps include measuring the force applied to the plunger via a load cell, The method according to claim 10, further comprising the step of calculating the energy at the point in time when a simulation of tire failure occurs. [Claim 12] The method according to claim 11, further comprising the step of selecting the damping means from one of the group of damping means having a spring constant in the range of 5 to 12 kg / mm, 13 to 22 kg / mm, or 30 to 50 kg / mm.

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