JP2018141710A - Tire testing equipment - Google Patents

Abstract

A test apparatus for simply and accurately evaluating the riding comfort of a tire with a lug.
A test apparatus 2 includes a traveling plate 6 on which a tire 4 travels, a mounting portion 20 on which the tire 4 is rotatably mounted and slidable in a vertical direction, and a desired longitudinal load applied to the tire 4. A load loader 26 for loading and a sensor 28 capable of detecting the vertical displacement or acceleration of the tire 4 are provided. Preferably, the device 2 further includes a load cell 12 for measuring a lateral force applied from the tire 4 to the traveling plate 6.
[Selection] Figure 2

Description

  The present invention relates to a tire testing apparatus. In detail, it is related with the test apparatus of the tire with a lug.

  Work vehicles such as agricultural vehicles and light civil engineering construction vehicles are equipped with lug tires in consideration of workability in wetlands and soft ground. The tread of a tire with lugs is provided with a number of lugs protruding outward in the radial direction. The rug sinks into the mud. Lugs can contribute to tire traction.

  Rug tires are required to improve ride comfort. Until now, in the evaluation of the ride comfort of a tire with lugs, a vehicle equipped with this tire was actually run. For example, when a vehicle is running, the vibration of the vehicle is measured by an acceleration sensor attached to the vehicle. Examination about vibration evaluation of tires with lugs is disclosed in Japanese Patent Application Laid-Open No. 2008-120167.

JP 2008-120167 A

  When the lug is grounded in the tire mounted on the left side of the vehicle, the vibration of the vehicle differs depending on whether the lug is grounded or the groove between the lugs is grounded in the tire mounted on the right side. In other words, the relationship between the timing at which the lugs of the tires mounted on the left and right sides of the vehicle come into contact with the timing at which the lugs of the tires mounted on the other side of the vehicle come into contact greatly affects the vibration of the vehicle. If a test that eliminates the influence of this timing can be performed, the ride comfort of the lug-equipped tire can be more accurately evaluated. Moreover, it takes time and effort to mount the tire on the vehicle and run the vehicle. There is also a strong demand to reduce these.

  An object of the present invention is to provide a test apparatus that simply and accurately evaluates the riding comfort of a tire with lugs.

  The present invention relates to a test apparatus for a tire with a lug including a main body and a lug protruding outward from the main body. The test apparatus includes a traveling plate on which the tire travels, a mounting portion on which the tire is rotatably mounted and slidable in a vertical direction, a load loader for applying a desired longitudinal load to the tire, and the above A sensor capable of detecting displacement or acceleration in the vertical direction of the tire is provided.

  Preferably, the apparatus further includes a load cell that measures a lateral force applied to the travel plate from the tire.

  Preferably, the apparatus further includes a pedestal and a linear guide. The tire travels on the traveling plate as the traveling plate slides on the base guided by the linear guide.

  Preferably, the load loader is a weight.

  Preferably, the apparatus further includes a shaft and a pair of bearings removably attached to both ends of the shaft. The bearing allows the shaft to rotate about its axis. The bearing is detachably attached to the attachment portion. By attaching the tire to the shaft, the tire is rotatably attached to the attachment portion via the shaft and the bearing.

  Preferably, the apparatus further includes an air conditioner capable of adjusting the environmental temperature during the test.

  In the test apparatus according to the present invention, the lug-equipped tire is attached to the attachment portion and is allowed to travel on the traveling plate. The displacement or acceleration of the tire at this time is measured. With this device, tires can be tested one by one, so this test result is not affected by the timing of other tire lugs touching. With this device, the ride comfort of the tire can be accurately evaluated. In tests using this device, it is not necessary to actually drive the vehicle. With this device, the evaluation of the riding comfort of the tire can be performed easily.

FIG. 1 is a front view showing a test apparatus according to an embodiment of the present invention. FIG. 2 is a side view of the test apparatus of FIG. FIG. 3 is a development view showing an example of a lug tire to be tested by the apparatus of FIG. 1. 4 (a), (b) and (c) are examples of results of testing with the apparatus of FIG.

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

  FIG. 1 is a front view showing a lug-equipped tire testing apparatus 2 according to the present invention. In FIG. 1, the position where the tire to be tested is set is indicated by a two-dot chain line. FIG. 2 is a side view of the test apparatus 2. FIG. 2 also shows the tire 4 to be tested. In FIG. 1, the direction indicated by the arrow X is the left direction, and the opposite direction is the right direction. In FIG. 2, the arrow Y indicates the front, and the opposite direction is the rear. 1 and 2, the direction indicated by the arrow Z is upward, and the opposite direction is downward.

  The test apparatus 2 includes a travel plate 6, a guide plate 8, a first linear guide 10, a load cell 12, a pedestal 14, a second linear guide 16, a frame 18, a mounting portion 20, a pair of bearings 22, a shaft 24, and a load loader. 26 and sensor 28.

  The travel plate 6 has a plate shape extending in the front-rear direction. The planar shape of the traveling plate 6 is a rectangle. The travel plate 6 has a travel surface 30 on which the tire 4 travels. The running surface 30 is a flat surface having no curvature. The travel plate 6 is typically made of a hard metal such as steel. The traveling plate 6 may be made of resin. The travel plate 6 may be wooden.

  The guide plate 8 has a plate shape extending in the front-rear direction. The guide plate 8 is located below the traveling plate 6. The guide plate 8 is typically made of a hard metal such as steel. The guide plate 8 may be made of resin. The guide plate 8 may be wooden.

  The first linear guide 10 is located between the travel plate 6 and the guide plate 8. The rail 32 of the first linear guide 10 extends in the left-right direction. By being guided by the first linear guide 10, the traveling plate 6 can slide in the left-right direction with respect to the guide plate 8. That is, the travel plate 6 is attached to the guide plate 8 via the first linear guide 10 so as to be slidable in the left-right direction.

  The load cell 12 is connected to the traveling plate 6 and the guide plate 8. As described above, the travel plate 6 is slidable with respect to the guide plate 8. However, since the load cell 12 is actually connected to the travel plate 6 and the guide plate 8, the travel plate 6 is connected to the guide plate 8. Will not slide against. The travel plate 6 is substantially fixed to the guide plate 8 by the load cell 12. As will be described later, since the tire 4 has lugs, a lateral force (lateral force) can be generated in the tire 4 when the tire 4 travels. The load cell 12 measures the lateral force applied from the tire 4 to the travel plate 6. The load cell 12 measures the lateral force generated in the tire 4 during traveling through the traveling plate 6.

  The base 14 is located below the guide plate 8. The pedestal 14 is fixed to the floor or the ground.

  The second linear guide 16 is located between the guide plate 8 and the pedestal 14. The rail 34 of the second linear guide 16 extends in the front-rear direction. By being guided by the second linear guide 16, the guide plate 8 can slide in the front-rear direction with respect to the base 14. By the second linear guide 16, the guide plate 8, the travel plate 6, the load cell 12, and the first linear guide 10 can be integrally slid on the base 14 in the front-rear direction.

  The frame 18 includes a pair of support columns 36 and an upper plate 38. Each column 36 is fixed to the base 14. The support column 36 extends upward from the base 14. The upper plate 38 is fixed to the upper end of the column 36. Although not shown, the center of the upper plate 38 is open when viewed from above. As will be described later, the loader 26 is passed through this opening.

  The attachment portion 20 includes a pair of arms 40 extending in the vertical direction and a ceiling portion 42 extending in the left-right direction when viewed from the front. Each arm 40 is attached to the column 36 of the frame 18 so as to be slidable in the vertical direction. That is, the attachment portion 20 can slide up and down with respect to the frame 18. The ceiling 42 is bridged between the arms 40 on both sides at the upper end of the arm 40.

  Each bearing 22 is fixed to the lower end of the arm 40. The bearing 22 is detachably attached to the arm 40. A hole is provided in the center of the bearing 22. A shaft 24 is passed through the holes of both bearings 22. Thereby, the bearing 22 is attached to both ends of the shaft 24. The bearing 22 allows the shaft 24 to rotate about its axis. The bearing 22 and the shaft 24 are detachable.

  A tire 4 to be evaluated is attached to the shaft 24. The shaft 24 is passed through a hole of a wheel on which the tire 4 is mounted. As described above, since the shaft 24 can be rotated around its axis by the bearing 22, the tire 4 can be rotated around this axis. As described above, the bearing 22 is attached to the attachment portion 20. That is, the tire 4 is rotatably attached to the attachment portion 20 via the shaft 24 and the bearing 22.

  The load loader 26 is located on the ceiling portion 42 of the attachment portion 20. In this embodiment, the load loader 26 is a weight 44. A weight 44 is placed on the ceiling 42. The weight 44 protrudes above the upper plate 38 through an opening provided in the upper plate 38 of the frame 18.

  The sensor 28 is attached to the load loader 26. The sensor 28 is a displacement sensor 28 that can measure the vertical displacement of the load loader 26 or an acceleration sensor 28 that can measure the vertical acceleration of the load loader 26. Both the displacement sensor 28 and the acceleration sensor 28 may be attached.

  As described above, in the device 2, the tire 4 is attached to the attachment portion 20 via the shaft 24 and the bearing 22. The load loader 26 is placed on the attachment portion 20, and the sensor 28 is attached to the load loader 26. That is, the tire 4, the shaft 24, the bearing 22, the attachment portion 20, the load loader 26, and the sensor 28 can slide up and down with respect to the frame 18.

  In the embodiment of FIGS. 1 and 2, the sensor 28 is attached to the load loader 26. The sensor 28 may be attached to the attachment portion 20. The sensor 28 is only required to be integrated with the tire 4 so as to slide up and down.

  FIG. 3 shows an example of a lug-equipped tire 4 that is evaluated by the device 2 of FIG. This figure is a developed view showing a part of the tread 50 of the tire 4 with lugs. In FIG. 3, the left-right direction is the axial direction of the tire 4. The vertical direction is the circumferential direction of the tire 4. In FIG. 3, the equator plane of the tire 4 is represented by the symbol CL. This lug-equipped tire 4 is attached to an agricultural vehicle. Examples of agricultural vehicles include tractors, rice transplanters, and transport vehicles. The tire 4 may be mounted on a light civil engineering construction vehicle such as a trencher.

  The tread 50 of the tire 4 forms a tread surface 52 that comes into contact with the ground. The tread 50 is made of a crosslinked rubber. The tread 50 includes a main body 54 and a lug 56. The lug 56 protrudes radially outward from the main body 54. A plurality of lugs 56 are provided. As shown in FIG. 3, these lugs 56 are alternately arranged on the left and right along the circumferential direction. A portion of the tread 50 between the lug 56 and the lug 56 is referred to as a lug bottom 58. The rug 56 sinks into the mud and scratches the mud. The lug 56 can contribute to the traction of the tire 4. The shape, interval, height, and the like of the lugs 56 are appropriately determined in consideration of the specifications of the tire 4 and the like.

  In the following, a method for evaluating the tire 4 shown in FIG. 3 using the apparatus 2 shown in FIGS. 1 and 2 will be described. This evaluation method includes a step in which the tire 4 is set in the device 2 and a step in which the performance of the tire 4 is measured.

  In the process of setting the tire 4 on the device 2, one bearing 22 is fixed to one end of the shaft 24. A tire 4 attached to the wheel is attached to the shaft 24. A bearing 22 is fixed to the other end of the shaft 24. These bearings 22 are attached to the arm 40 of the attachment portion 20. Thus, the tire 4 is attached to the attachment portion 20. The tire 4 is placed on the traveling plate 6. The tire 4 comes into contact with the traveling surface 30 of the traveling plate 6. A load is applied to the tire 4 by the load loader 26. In this embodiment, a weight 44 is placed on the ceiling portion 42 of the mounting portion 20. The tire 4 is pressed against the traveling plate 6. By adjusting the weight of the weight 44, a desired longitudinal load is applied to the tire 4.

  In the step of measuring the performance of the tire 4, the guide plate 8 is slid in the front-rear direction on the pedestal 14 at a desired speed. The traveling plate 6 slides along with the guide plate 8 in the front-rear direction. Thus, the tire 4 travels on the travel plate 6. The tire 4 travels on the travel plate 6 with a desired load. Since the lug 56 exists, the tire 4 vibrates in the vertical direction as the vehicle travels. The displacement in the vertical direction at this time is measured by the displacement sensor 28. The acceleration in the vertical direction is measured by the acceleration sensor 28. Lateral force generated in the tire 4 as it travels is measured by the load cell 12 via the travel plate 6. The riding comfort of the tire 4 is evaluated by these displacement, acceleration, and lateral force.

  Below, the effect of this invention is demonstrated.

  In the test apparatus 2 according to the present invention, the lug-equipped tire 4 is attached to the attachment portion 20 and travels on the traveling plate 6. The displacement and acceleration of the tire 4 at this time are measured. In this apparatus 2, since the tires 4 can be tested one by one, the test result is not affected by the timing at which the lugs 56 of the other tires 4 come into contact with the ground. With this device 2, the riding comfort of the tire 4 can be evaluated with high accuracy.

  In the evaluation using this device 2, it is not necessary to actually drive the vehicle. There is no need to mount the tire 4 on the vehicle, and there is no need to drive the vehicle. With this device 2, the riding comfort of the tire 4 can be easily evaluated. Furthermore, since only one tire 4 is required for evaluation, the evaluation cost is also reduced.

  In order to evaluate the riding comfort of the lug-equipped tire 4, it is conceivable to use a conventional drum-type running test machine. In this testing machine, the tire 4 runs on the outer surface or inner surface of the drum. The running surface of the drum has a curvature. The contact length of the tire 4 is different when traveling on the traveling surface of the drum and when traveling on the ground surface close to a flat surface. The number of lugs 56 that are in contact with the ground and the range of the lugs 56 differ between when traveling on the traveling surface of the drum and when traveling on a flat surface. This affects the vibration of the tire 4. In a drum-type running test machine, the ride comfort of the lug-equipped tire 4 may not be accurately evaluated.

  In the test apparatus 2 according to the present invention, the traveling surface 30 is a flat surface. The contact length when the lug-equipped tire 4 travels on the traveling surface 30 of the device 2 is close to the contact length when traveling on the actual ground. With this device 2, the ride comfort of the lug-equipped tire 4 can be accurately evaluated.

  In order to evaluate the riding comfort of the lug-equipped tire 4, it is conceivable to use a conventional flat belt type traveling tester. The running surface of this running test machine is a plane. However, the flat belt type running tester is expensive. Furthermore, if a tire having a lug protruding outward is run like a tire with a lug, the belt may be damaged.

  In the test apparatus 2 according to the present invention, the tire 4 travels on the travel plate 6. The travel plate 6 is made of metal such as steel, resin, or wood. These slide with a linear guide. These are all inexpensive. This device 2 can be constructed at low cost. Furthermore, the traveling plate 6 made of these materials is not easily broken. The travel plate 6 is prevented from being damaged even when the lug-equipped tire 4 travels on the travel plate 6.

  In the conventional running test machine, the tire 4 is pressed against the running surface in order to apply a desired load to the tire. The distance between the rotation axis of the tire and the running surface is fixed in this state. The tire is caused to travel on the traveling surface while the distance between the rotation axis of the tire and the traveling surface is kept constant. In actual travel, the tire 4 with a lug includes a large number of lugs 56, and thus the tire 4 is greatly displaced in the vertical direction. Further, the vertical displacement also changes due to the change in the rigidity of the lug 56. In a conventional running test machine, it may happen that vibrations in actual running cannot be accurately reproduced.

  As shown in FIGS. 1 and 2, in this embodiment, a weight 44 is used as the load loader 26. Thus, it is preferable to load the tire 4 with a desired load by placing the weight 44 thereon. By using the weight 44 as the load loader 26, the shaft of the tire 4 can be displaced up and down while a desired load is applied. In the test apparatus 2, a vibration similar to that in actual traveling can be reproduced after a desired load is applied to the tire 4. With this device 2, the ride comfort of the lug-equipped tire 4 can be evaluated with high accuracy.

  In FIG. 2, what is indicated by a double arrow L is the length of the traveling plate 6. The length L is preferably 1 m or more. By setting the length L to 1 m or more, the tire 4 can travel a sufficient distance for evaluation of ride comfort in this device 2. With this device 2, the ride comfort of the lug-equipped tire 4 can be evaluated with high accuracy. The length L is preferably 3 m or less. By setting the length L to 3 m or less, the size of the device 2 can be suppressed. This device 2 takes up no space. This device 2 is easy to install.

  The test apparatus 2 preferably further includes an air conditioner that can adjust the environmental temperature. As the temperature fluctuates, the vibration may change. By providing an air conditioner, ride comfort can be evaluated under a certain temperature. With this device 2, the ride comfort of the lug-equipped tire 4 can be evaluated with high accuracy.

  In order to evaluate the lateral force generated in the tire 4 during traveling, it is preferable to use a load cell 12 as shown in FIGS. For example, a method of making the traveling plate 6 slidable in the left-right direction and measuring the vibration in the left-right direction with an accelerometer or a displacement meter is also conceivable. In this method, the traveling plate 6 may flow in the left-right direction. By measuring the lateral force applied to the traveling plate 6 by the load cell 12, the traveling plate 6 is prevented from flowing in the left-right direction. In this method, the lateral force generated in the tire 4 can be accurately measured via the travel plate 6. With this device 2, the ride comfort of the lug-equipped tire 4 can be evaluated with high accuracy.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

  With the evaluation apparatus provided with the configuration shown in FIGS. 1 and 3, the lug-equipped tire was evaluated. The tire size is 13.8-28-AT50. An acceleration sensor and a displacement sensor are attached to the weight of this device. A vertical load of 5 kN was applied to the tire by this weight. By sliding the running plate, the tire was run on the running plate at a speed of 1 km / h. FIG. 4A shows the displacement in the vertical direction measured by the displacement sensor. FIG. 4B shows the vertical acceleration measured by the acceleration sensor. FIG. 4C shows the lateral force measured by the load cell.

  As shown in FIGS. 4A to 4C, in this device, the vertical displacement and acceleration of the tire and the tire are loaded without being affected by the timing at which the lugs of other tires come into contact with the ground. Lateral force is measured. From this evaluation result, the superiority of the present invention is clear.

  The evaluation apparatus according to the present invention can be used for evaluation of tires with lugs for various agricultural vehicles and light civil engineering construction vehicles.

DESCRIPTION OF SYMBOLS 2 ... Test apparatus 4 ... Tire 6 ... Traveling plate 8 ... Guide plate 10 ... 1st linear guide 12 ... Load cell 14 ... Base 16 ... 2nd linear guide 18 ... Frame 20 ... Mounting part 22 ... Bearing 24 ... Shaft 26 ... Load loader 28 ... Sensor 30 ... Running surface 32, 34 ... Rail 36 ... Post 38 ... Upper plate 40 ... Arm 42 ... Ceiling 44 ... Weight 50 ... Tread 52 ... Tread surface 54 ... Main body 56 ... Lug 58 ... Rug bottom

Claims (6)

The tread is a test apparatus for a tire with a lug comprising a main body and a lug protruding outward from the main body,
A traveling plate on which the tire travels, a mounting portion on which the tire is rotatably mounted and slidable in a vertical direction, a load loader for applying a desired longitudinal load to the tire, and a vertical direction of the tire Lug tire testing device including a sensor capable of detecting displacement or acceleration.   The test apparatus for a tire with lugs according to claim 1, further comprising a load cell for measuring a lateral force applied from the tire to the travel plate.   3. The lug-equipped tire according to claim 1, further comprising a pedestal and a linear guide, wherein the tire travels on the traveling plate when the traveling plate slides on the pedestal guided by the linear guide. Test equipment.   The test apparatus for a tire with lugs according to any one of claims 1 to 3, wherein the load loader is a weight. A shaft and a pair of bearings detachably attached to both ends of the shaft;
The shaft is rotatable about the axis by the bearing,
The bearing is detachably attached to the attachment part,
The test apparatus for a tire with a lug according to any one of claims 1 to 4, wherein the tire is rotatably attached to the attachment portion via the shaft and the bearing by attaching the tire to the shaft.   The test apparatus for a tire with lugs according to any one of claims 1 to 5, further comprising an air conditioner capable of adjusting an environmental temperature during the test.

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