JP2007292587A - Friction testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction testing machine capable of measuring easily rolling friction and sliding friction by the compact testing machine of a suppressed cost, and capable of obtaining a treading behavior of a tire close to actual one. <P>SOLUTION: This friction testing machine of the present invention has a support means 1 for supporting rotatably a disk-like rubber sample S, a loading means 2 for loading a prescribed load onto the rubber sample S supported by the support means 1, and a moving means 3 provided to reciprocation-move rectilinearly a friction test face 32 contacting with the rubber sample S loaded with the load by the loading means 2. The friction testing machine is provided further a locking means 4 allowing the rotation of the rubber sample S when the friction test face 32 is moved along one direction, and for detering the rubber sample S from being rotated when moved along the other direction, and a measuring means 5 for measuring a moving-directional force on the friction test face 32 acting on the rubber sample S contacting with the friction test face 32, when the friction test face 32 is moved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rubber friction tester, and more particularly to a friction tester suitable for measuring both rolling friction and sliding friction.

  2. Description of the Related Art Conventionally, as a rubber friction tester, for example, a friction tester that can measure a friction coefficient using a rotating drum is known (see, for example, Patent Document 1). This friction tester enables both the rotating drum and the rubber sample to be rotated by the drive motor, thereby allowing the friction coefficient to be measured at an arbitrary slip ratio by continuously changing the slip ratio from 0 to 100%. ing.

However, when the rubber sample is rotated and driven by the drive motor as described above, the apparatus becomes large and expensive, so in the new blended rubber, only both rolling friction and sliding friction are used in the laboratory test. It is difficult to introduce if you want to investigate. Further, since the rubber sample is brought into contact with the outer peripheral surface of the drum having the curvature, the ground contact behavior is different from the case of the tire that contacts the flat road surface.
JP 2000-329687 A

  An object of the present invention is to provide a friction tester that can easily measure rolling friction and sliding friction with a small-sized and low-cost tester and can be close to the actual ground contact behavior of a tire.

  The friction tester of the present invention that achieves the above object includes a support means for rotatably supporting a disk-shaped rubber sample, a load means for applying a load to the rubber sample supported by the support means, and the load means. A moving means in which a friction test surface that contacts a loaded rubber sample is linearly reciprocally movable, and the rubber sample is allowed to rotate when the friction test surface of the moving means moves in one direction. A locking means for preventing the rotation of the rubber sample when moving in the direction, and a measuring means for measuring a force in the moving direction of the friction test surface acting on the rubber sample contacting the friction test surface when the friction test surface is moved. It is characterized by comprising.

  According to the present invention described above, the disk-shaped rubber sample is rotatably supported by the support means, and the test is performed without applying a rotational drive to the rubber sample, which causes an increase in size and cost. The drive motor for the rubber sample can be omitted, and the friction tester can be downsized to reduce the cost. On the other hand, the lock means allows the rubber sample to rotate when the friction test surface moves in one direction, and prevents the rotation when the rubber sample moves in the other direction. Sliding friction can be measured. Therefore, it is possible to easily measure rolling friction and sliding friction with a small and low-cost testing machine.

  In addition, since the friction test surface in contact with the rubber sample can be linearly moved back and forth, the state in which the rubber sample is in contact with the friction test surface can be made to be the same state as the state in which the tire is in contact with the road surface. . Therefore, the behavior of the rubber sample in the friction test can be brought close to the actual ground contact behavior of the tire.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view showing an embodiment of the friction testing machine of the present invention with the locking means omitted, FIG. 2 is a side view of the supporting means, and FIG. 3 is an enlarged view of the locking means. In the figure, 1 is a support means for rotatably supporting a disk-shaped rubber sample S, 2 is a load means for applying a load to the rubber sample S supported by the support means 1, and 3 is a rubber sample S loaded with a load. A moving means 4 is provided so that the friction test surface 32 can be reciprocated linearly. 4 allows the rubber sample S to rotate when the friction test surface 32 moves in one direction, and the rubber sample S moves when the friction test surface 32 moves in the other direction. Locking means 5 for preventing the rotation of the friction test surface 32 is a measuring means for measuring the force (force in the moving direction of the friction test surface 32) acting on the rubber sample S that contacts the friction test surface 32 when the friction test surface 32 moves. A gate-shaped support member 7 is erected on the base 6, and the support means 1 is attached to the front side of the support member 7 via the measurement means 5.

  The support means 1 has a rotating shaft 9 that is horizontally provided on a block-like support 8 so as to be rotatable. The rotating shaft 9 extends forward from the center of the support 8, and a sample mounting portion 10 to which the rubber sample S can be detachably mounted is provided at the tip. The disc-shaped rubber sample S is formed with a through hole S1 for attachment to the rotating shaft 9 at the center. The disc-shaped rubber sample S has a through-hole S1 for attachment to the rotating shaft 9 at the center, and a disc-shaped mounting plate 11 fixed to the tip of the rotating shaft 9 and the tip of the rotating shaft 9 The sample mounting portion 10 can be detachably mounted by a holding bolt 13 that is detachably screwed into the female screw portion formed in the above.

  The measuring means 5 includes a pair of parallel left and right leaf springs 15 that support the support 8 of the support means 1, and a strain gauge 16 that is attached to both the leaf springs 15 and detects the distortion of the leaf springs 15. . The gate-shaped support member 7 is composed of left and right leg portions 7a and a horizontally disposed portion 7b horizontally disposed between the upper portions of the leg portions 7a, and the horizontally disposed portion 7b is rotatably attached to both leg portions 7a. The rotating body is configured. The left and right leaf springs 15 are fixed to both ends of a lateral portion 7b whose rear end portion rotates. The front ends of a pair of leaf springs 15 that are laterally provided forward from the horizontal portion 7 b are fixed to both ends of the support 8. Thereby, the support body 8 (rotating shaft 9) can swing up and down around the horizontal portion 7b by the rotation of the horizontal portion 7b.

  A fixed shaft 17 projects from the center of the horizontal portion 7b toward the rear. The fixed shaft 17 is disposed so as to be positioned on the same straight line as the rotating shaft 9, and the rotating shaft 9 and the fixed shaft 17 are both in a substantially horizontal state with the rubber sample S mounted in the middle thereof. A counterweight 18 is provided for balancing so that The load means 2 is connected to the rear end portion of the fixed shaft 17.

  The load means 2 has a linearly extending body 19 made of a wire or the like having one end connected to the fixed shaft 17 and a weight 20 connected to the other end of the linearly extending body 19. A linearly extending body 19 extending upward from the fixed shaft 17 is disposed so as to extend downward via left and right pulleys 22 provided on both sides of a column 21 erected on the base 6, and at the lower end thereof. A weight 20 is attached. The rear end portion of the fixed shaft 17 is pulled up by the weight 20, whereby the sample mounting portion 10 of the rotating shaft 9 is pushed down, and a constant load can be applied to the rubber sample S mounted on the sample mounting portion 10. Yes.

  The moving means 3 is installed on the base 6 below the supporting means 1. In this moving means 3, a pair of front and rear guide rods 23 extending left and right are disposed on the base 6, and a rotatable ball screw 24 extending left and right is disposed between the guide rods 23. The ball screw 24 is engaged with a movable body 25 that is movable to the left and right while being guided by the guide rod 23. The moving body 25 is disposed below the sample mounting portion 10 of the rotating shaft 9 so as to be reciprocally movable in the horizontal direction along the ball screw 24, and left and right leg portions 26 that are screwed into the ball screw 24. It is composed of a rectangular parallelepiped moving body main body 27 fixed on the leg portion 26.

  A drive motor 28 for moving the moving body 25 is disposed on the base 6 on one end side of the ball screw 24, and a pulley 29 fixed to the rotating shaft 28 a of the drive motor 28 and one end portion of the ball screw 24 are fixed. A drive belt 31 is wound around the provided pulley 30. As the drive motor 28 rotates in one direction, the ball screw 24 rotates in one direction, whereby the moving body 25 moves in one direction at a constant speed. Further, when the drive motor 28 rotates in the reverse direction, the ball screw 24 rotates in the reverse direction, whereby the moving body 25 moves in the reverse direction (the other direction) at a constant speed.

  On the upper surface 27a of the movable body 27, a friction plate 33 having a friction test surface 32 (in the figure, a test surface on which a sphere x is arranged) used for a friction test is detachably provided by a double-sided tape or the like. .

  Sensors 34 </ b> A and 34 </ b> B that detect the reciprocating movement of the moving body 25 provided with the friction test surface 32 are provided at two positions on the left and right sides of the front guide rod 23. When the detection piece 35 for detecting by the sensors 34A and 34B protrudes from the moving body 27 and the detection piece 35 comes to the side of the sensors 34A and 34B, the sensors 34A and 34B detect it and send a detection signal. The data is output to a control device (not shown).

  When the detection piece 35 of the moving body 25 moving in the right direction in FIG. 1 is detected by the right sensor 34B and a detection signal is input from the sensor 34B to the control device, the rotation direction of the drive motor 28 is reversed. The movement direction of 25 is reversed to the left, and the movement direction of the friction test surface 32 can be reversed. Further, when the detection piece 35 of the moving body 25 moving in the left direction in FIG. 1 is detected by the left sensor 34A and a detection signal is input from the sensor 34A to the control device, that is, when the moving body 25 reciprocates, the driving is performed. The rotation of the motor 28 is stopped, and the movement of the moving body 25 is stopped.

  As shown in FIGS. 2 and 3, the locking means 4 is a ratchet gear 36 fixed to the rear end portion of the rotating shaft 9 of the support means 1 and is rotatably disposed on the front surface of the support body 8. A clutch (claw) 37 is engaged. When the clutch 37 is engaged with the ratchet gear 36, the rotation shaft 9 of the support means 1 is allowed to rotate in one direction indicated by the arrow in FIG. 3, but is prevented from rotating in the opposite direction. It has become.

  An image sensor 38 that can read an image of the rubber sample S under test supported by the support unit 1 is installed on the left side and the front side of the sample mounting unit 10, and the rubber sample S is read using the image read into the image sensor 38. The deformation behavior of can be observed. As the image sensor 38, a video camera, an X-ray image sensor, or the like can be used. In particular, the X-ray image sensor can be preferably used because it can obtain an image of an internal state that is not visible from the outside, in which the protrusion bites into the rubber sample S when it is moved on the protrusion.

  In order to perform a friction test using the above-described friction tester, first, the rubber sample S is mounted on the sample mounting portion 10 provided at the tip of the rotating shaft 9, and the rubber sample S is loaded on the friction test surface 32 by the load means 2. Press with a constant load. In this state, the friction tester is operated.

  The driving motor 28 is driven, and the moving body 25 moves in one direction (right direction in FIG. 1) at a constant speed by the rotation of the ball screw 24. Thereby, the rubber sample S pressed against the friction test surface 32 is pressed from one end (right end) side to the other end (left end) side of the friction test surface 32 while rolling. At that time, the strain of the leaf spring 15 that supports the supporting means 1 to which the rubber sample S is attached is detected by the strain gauge 16. A strain signal detected by the strain gauge 16 is input to a control device (not shown), and a frictional force (rolling friction) is calculated in accordance with the input program.

  When the right sensor 34B detects the detection piece 35, a detection signal is input from the sensor 34B to the control device. The control device switches the rotation direction of the drive motor 28 to the reverse direction and reverses the movement direction of the moving body 25. Accordingly, the moving body 25 moves at a constant speed in the reverse direction (left direction in FIG. 1).

  The rubber sample S pressed against the friction test surface 32 is pressed while sliding from the other end side to the one end side of the friction test surface 32 without rotating because the rotation of the rotating shaft 9 is prevented by the locking means 4. . The strain of the leaf spring 15 is detected by the strain gauge 16, and the detected strain signal is input to the control device, where the frictional force (sliding friction) is similarly calculated.

  When the detection piece 35 of the moving body 25 moving in the left direction is detected by the left sensor 34A, the control device that has received the detection signal from the sensor 34A stops the rotation of the drive motor 28, and the test ends. From the start of operation of the friction tester to the end of the test, the image sensor 38 operates, and the behavior of the rubber sample S being deformed is captured as an image.

  In the present invention described above, since the rubber sample S is merely rotatably supported on the support means 1 and the rubber sample S is not rotationally driven by a motor or the like, it causes an increase in size and cost. By omitting the drive motor for the rubber sample S, the friction tester can be miniaturized and the cost can be reduced. On the other hand, the rotation of the rubber sample S is allowed when the friction test surface 32 is moved in one direction by the lock means 4, Since rotation is prevented when moving in the reverse direction, rolling friction can be measured when the rubber sample S rotates, and sliding friction can be measured when the rubber sample S is prevented from rotating. Therefore, it is possible to easily measure rolling friction and sliding friction with a small and low-cost testing machine.

  Further, since the friction test surface 32 of the moving means 3 in contact with the rubber sample S can be linearly reciprocated, the state in which the rubber sample S is in contact with the friction test surface 32 is in a state where the tire is grounded on a flat road surface. Can be in a similar state. Therefore, the behavior of the rubber sample S during the friction test can be brought close to the actual ground contact behavior of the tire. Furthermore, since the position of the rubber sample S does not change, the deformation behavior of the rubber sample S can be easily captured and observed by the image sensor 38.

  In the present invention, the measuring means 5 may be configured using a load cell instead of the above-described configuration. The load means 2 connects the weight 20 to the linear extension 19 and applies a constant load to the rubber sample S. However, the load means 2 connects the weight 20 to the linear extension 19 in a detachable manner. You may enable it to load a different load by exchanging 20. Further, the moving means 3 moves the moving body 25 at a constant speed, but it may move at a variable speed. Further, the lock unit 4 may be configured to allow the rotation of the rubber sample and the rotation prevention of the rubber sample by engaging and disengaging the clutch 37 to the rotating shaft 9 side instead of the above-described configuration. Further, the friction tester described above may be configured to perform a rolling friction test after performing a sliding friction test, and the present invention is not limited to the configuration of the friction tester of the above-described embodiment. Needless to say.

It is a schematic perspective view which shows one Embodiment of the friction tester of this invention, omitting a locking means. It is a side view of a support means. It is an enlarged front view of a locking means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support means 2 Load means 3 Moving means 4 Locking means 5 Measuring means 7 Support member 7b Lateral part (rotating body)
DESCRIPTION OF SYMBOLS 8 Support body 9 Rotating shaft 10 Sample mounting part 14 Gear 15 Leaf spring 16 Strain gauge 17 Fixed shaft 19 Linear extension body 20 Weight 25 Moving body 27 Moving body main body 27a Upper surface 34A, 34B Sensor 37 Clutch 38 Image sensor S Rubber sample

Claims (9)

  A support means for rotatably supporting a disk-shaped rubber sample, a load means for applying a load to the rubber sample supported by the support means, and a friction test surface on which the rubber sample loaded by the load means contacts. A linearly reciprocating moving means, and allowing the rubber sample to rotate when the friction test surface of the moving means moves in one direction, and preventing the rubber sample from rotating when moving in the other direction. A friction testing machine comprising: locking means; and measuring means for measuring a force in a moving direction of the friction test surface acting on a rubber sample that is in contact with the friction test surface when the friction test surface is moved.   The friction tester according to claim 1, further comprising a sensor that detects reciprocal movement of the friction test surface of the moving unit, and configured to be able to reverse the movement direction of the friction test surface by a detection signal of the sensor.   The friction tester according to claim 1, further comprising an image sensor capable of reading an image of a rubber sample supported by the support means.   4. The friction tester according to claim 1, wherein the support means includes a rotating shaft that is provided so as to be rotatable and has a sample mounting portion at a distal end portion on which the rubber sample can be detachably mounted.   The said moving means has a moving body which provided the said friction test surface on the upper surface, and this moving body was arrange | positioned under the said support means so that a reciprocating movement is possible at a constant speed in a horizontal direction. The friction tester according to the above.   The friction testing machine according to any one of claims 1 to 5, wherein the load means includes a weight for applying a constant load to the rubber sample supported by the support means.   The lock means includes a clutch and a ratchet gear that allow rotation of the rubber sample when the friction test surface of the moving means moves in one direction and prevent rotation of the rubber sample when moved in the other direction. The friction tester according to any one of 1 to 6.   The friction tester according to any one of claims 1 to 7, wherein the measuring means includes a pair of parallel leaf springs that support the supporting means, and a strain gauge that detects strain of the leaf springs.   The support means has a rotation shaft that is rotatably disposed on a support body, the rotation shaft is provided with a sample mounting portion to which the rubber sample can be detachably mounted at a tip portion, and the measurement means is mounted on a base. A pair of parallel left and right leaf springs installed laterally from a standing support member, and a strain gauge for detecting the strain of the leaf spring, the support member having a pivoting body horizontally arranged, The front end of the leaf spring is fixed to the support body of the support means, and the rear end portion is fixed to the rotating body, and the rotating shaft is configured to swing up and down around the rotating body by the rotation of the rotating body. A fixed shaft projecting rearward from the rotating body, a counterweight is provided in the middle of the fixed shaft, and the load means is connected to the rear end, and the load means is connected to the fixed shaft at one end. Are connected, and are linearly extended so as to extend downward after extending upward, and A weight connected to the other end of the linearly extending body, and the moving means has a moving body provided with the friction test surface on an upper surface, the moving body being a sample mounting portion of a rotating shaft of the supporting means The lock means is disposed in a horizontal direction so as to be reciprocally movable at a constant speed, the ratchet gear fixed to the rotating shaft of the support means, and the support means of the support means are rotatably disposed, The friction tester according to claim 1, 2 or 3, further comprising a clutch that engages with the ratchet gear.

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