JP2002071531A - Tire damping coefficient measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire damping coefficient measuring device capable of measuring the damping of a large-scaled tire such as a tire for a construction vehicle. SOLUTION: A movable carriage 26 is pulled to a horizontal direction by a hydraulic cylinder 32 in a state that an OR tire 20 is pressed against the movable carriage 26 with a prescribed charge. At that time, the OR tire 20 pressed against the movable carriage 26 is elastically deformed. When the connection of the movable carriage 26 to the hydraulic cylinder 32 is separated by a separating device 38, the horizontal damped vibration of the movable carriage 26 is carried out with the elastic force of the OR tire 20. The acceleration of the damped vibration movable carriage 26 is measured by an acceleration sensor 54, and the damping coefficient of the OR tire 20 is calculated from the fluctuation difference of the measured results.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire damping coefficient measuring device for measuring a damping coefficient (attenuation coefficient) of a construction vehicle tire (OR tire).

[0002]

2. Description of the Related Art A construction vehicle called a wheel loader is used for loading and unloading ore in a mine, transporting and laying aggregate, and loading and unloading earth and sand. Vehicles called container stackers are used for loading and unloading containers on land and in ships.

[0003] Each of the above-mentioned vehicles has large load fluctuations when loading and unloading cargo, and accompanying such fluctuations (particularly during loading).
Since the vehicle vibrates largely in the front-back and lateral directions, the running stability of the vehicle deteriorates. In addition, there is a problem that the accuracy of loading / unloading points is also deteriorated.

Here, in order to solve the above problem, tires for construction vehicles having good vibration damping properties have been developed. However, due to the large size of the tires, longitudinal and lateral vibration damping properties have been developed. There was no suitable device to measure

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-described circumstances, and has as its object to provide a tire damping coefficient measuring apparatus capable of measuring the damping property of a large tire such as a tire for a construction vehicle. Make it an issue.

[0006]

According to a first aspect of the present invention, there is provided a tire damping coefficient measuring device, comprising: a movable member movable in one direction; and a traction member for pulling the movable member pressed against a fixed tire in one direction. A detaching member that disconnects the connection between the moving member and the traction member, and attached to the moving member,
An acceleration measuring device configured to measure an acceleration of the moving member that has been disconnected from the towing member and that has attenuated and vibrated in one direction.

Next, the operation and effect of the tire damping coefficient measuring device according to the first aspect will be described.

[0008] A load is applied to the fixed tire, and the tire is pressed against the moving member with a predetermined pressing force.

Here, a traction member is connected to the moving member, and the moving member is pulled in one direction by the traction member under a pressing force from the tire. At this time, the vicinity of the contact portion of the tire with the moving member is elastically deformed.

When the connection between the moving member and the traction member is disconnected by the separating member while the moving member is being pulled by the traction member, the tire is pressed against the moving member and the tire is elastically deformed. The member moves in a direction opposite to the direction pulled by the traction member. That is, the moving member performs damped vibration.

At this time, the acceleration of the moving member that is dampingly vibrating is measured by an acceleration measuring device. Then, a damping coefficient (attenuation coefficient) of the tire is calculated from the measured fluctuation value of the acceleration.

According to the tire damping coefficient measuring device of the present invention, even in the case of a large tire such as a construction vehicle tire, the tire damping property can be measured.

In particular, when measuring the damping property of a tire having a large mass such as a large tire, the influence of the inertial force of the moving member which attenuates and vibrates can be minimized by pulling the moving member having a relatively small mass. Thus, the tire damping coefficient can be measured more accurately.

The horizontal direction is most preferable as one direction in which the moving member moves, but the moving direction of the moving member is preferably set in a range that does not affect the measurement of the tire damping property with respect to a plane passing through the axis of the tire. Therefore, it may be inclined to some extent (within 1 °).

According to a second aspect of the present invention, there is provided a tire damping coefficient measuring device, wherein a measuring member for measuring a tensile force of the traction member is provided.

Next, the operation and effect of the tire damping coefficient measuring device according to the second aspect will be described.

The tensile force of the traction member can be measured by the measuring member. For this reason, the moving member can be pulled with an appropriate tensile force corresponding to the type of the tire to be measured. As a result, the damping coefficient of the tire can be accurately measured.

In the tire damping coefficient measuring device according to the third aspect, a friction increasing means for increasing friction with the tire is provided on a contact surface of the moving member against which the tire is pressed.

Next, the operation and effect of the tire damping coefficient measuring device according to the third aspect will be described.

The contact surface of the moving member against which the tire is pressed is provided with friction increasing means for increasing the friction with the tire. Therefore, in a state where the tire is pressed against the contact surface of the moving member, the moving member is moved by the traction member. When you pull
It is possible to prevent the tire from sliding on the contact surface of the moving member as much as possible. For this reason, the damping property of the tire can be accurately measured.

In this case, as the friction increasing means, it is preferable to form a projection on the contact surface of the moving member in a direction substantially perpendicular to the moving direction of the moving member.

According to a fourth aspect of the present invention, the traction member is a hydraulic cylinder.

Next, the operation and effect of the tire damping coefficient measuring device according to the fourth aspect will be described.

By using a hydraulic cylinder as the traction member, a conventionally available device can be applied as it is. Further, a large tensile force required to pull the moving member against which the large tire is pressed can be easily obtained.

According to a fifth aspect of the present invention, in the tire damping coefficient measuring apparatus, the measuring member is a load cell.

Next, the operation and effect of the tire damping coefficient measuring device according to the fifth aspect will be described.

By using a load cell as a measuring member, a commercially available device can be applied as it is.

According to a sixth aspect of the present invention, there is provided a tire damping coefficient measuring device, further comprising a load applying device for fixing the tire and pressing the tire against the moving member.

Next, the operation and effect of the tire damping coefficient measuring device according to claim 6 will be described.

The provision of the load load device for pressing the tire against the moving member allows the tire to be pressed against the moving member with a load corresponding to the type of the tire to be measured. For this reason, the damping property of the tire can be accurately measured.

According to a seventh aspect of the present invention, there is provided a tire damping coefficient measuring device, comprising: a supporting member; a load-loading device which is provided so as to be movable in one direction, and which fixes the tire and presses the tire against the supporting member with a predetermined load. A traction member that pulls the load device in one direction in a state where the tire is pressed against the support member, a separating member that disconnects the connection between the load device and the traction member, and a traction member attached to the load device or the tire. An acceleration measuring device that measures the acceleration of the tire that has been disconnected in one direction and has attenuated and vibrated,
Is characterized by including.

Next, the operation and effect of the tire damping coefficient measuring device according to claim 7 will be described.

According to the first aspect of the present invention, the moving member against which the tire is pressed is pulled by the traction member,
Although the moving member was damped and vibrated to measure the tire damping property, as in the present invention, a load loading device for fixing the tire pressed against the support member was provided so as to be movable in one direction, By pulling the load device by the traction member and damping and vibrating the load load device and thus the tire,
Tire damping may be measured.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tire damping coefficient measuring device according to one embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the tire damping coefficient measuring apparatus 10 includes a pair of side wall frames 14 (only one side wall frame 14A is shown in FIG. 1) fixed to a floor surface 12. Wheels (not shown) are attached to the other side wall frame (not shown), and
You can move up.

A recess 16 extending in the vertical direction (the direction of arrow A in FIG. 1) is formed on the side surface of each side wall frame 14, and a bogie that moves in the recess 16 in the vertical direction. (Not shown) are provided.

Each truck has a shaft 18 (one shaft 18 in FIG. 1) so as to be perpendicular to the side surface.
(Only A is shown) is provided so as to protrude, so that the distal ends of the shafts 18 can be connected to each other.

Here, the OR tire 20 on the shaft 18
Is mounted by fitting the rim-assembled OR tire 20 into one shaft 18A as it is, and then connecting the tip of the other shaft to the tip of one shaft 18A.

As described above, the OR tire 2 is attached to the shaft 18.
Since the mounting of the OR tire 20 can be reduced and speeded up since the mounting of the OR tire 20 can be performed and fixed in a state where the 0 is mounted on the rim.

Further, a control device (not shown) as a load application device attached to the side wall frame 14 is electrically connected to the truck, and the control device can control the vertical movement of the truck. Has become.

Although not shown, the control device may be a conventionally known device. For example, the control device may be constituted by a hydraulic cylinder mounted on a trolley for moving the trolley vertically and a pump for adjusting the hydraulic pressure inside the hydraulic cylinder. Good.

On the other hand, as shown in FIGS. 1 and 2, the tire damping coefficient measuring device 10 has a base 22 disposed between the side wall frames 14. Rails 24 are formed on the base 22 in parallel with a certain interval.

A moving table 26 is mounted on the rail 24. The moving table 26 includes a moving table main body 28.

Here, the movable base body 28 has a planar upper surface plate 28A and a lower surface plate 28B, and four slide portions 30 are provided at the bottom of the lower surface plate 28B.

The slide portion 20 is formed in a U-shaped cross section so as to cover the rail 24, and is in contact with the rail 24 via a hard sphere (not shown) rotatably provided on the inner surface. When the hard sphere rotates on the rail 24, the moving table 26 can move smoothly on the rail 24. As the combination of the rail 24 and the slide portion 30, it is preferable to use an LM guide which is conventionally commercially available.

On the other hand, the OR tire 20 is pressed against the upper surface plate 28A of the movable base body 28 with a predetermined pressing force as described later.

Here, as shown in FIG.
The surface of the upper plate 28A of FIG. 8 is knurled, and a projection 29 as a friction increasing means is machined in a direction substantially perpendicular to the moving direction of the moving table 26. This top plate 2
When the OR tire 20 is pressed on 8A, the protrusion 29 on the upper surface plate 28A cuts into the surface of the OR tire 20 to increase the friction with the OR tire 20.
As a result, it is possible to prevent the OR tire 20 from slipping on the upper surface plate 28A when the movable table 26 is pulled by the hydraulic cylinder 32 described later.

Even if the projection 29 is not formed on the upper plate 28A, it is possible to increase the friction with the OR tire 20 by forming a mesh pattern or unevenness on the upper plate 28A by a known means. it can.

A load cell 34 is mounted on the side of the movable base body 28. This load cell 34
Conventionally available product (Lu-20TE, manufactured by Kyowa Dengyo)
Is used.

Here, the load cell 34 is made of an outer box 34A.
And a columnar member 34B housed in the outer box 34A. A strain gauge (not shown) is adhered around the cylindrical member 34B, and a load button (not shown) is attached to an end of the cylindrical member 34B.

According to the load cell 34, when a tensile load acts on the load button, a strain proportional to the stress is generated, and the electric resistance of the strain gauge changes according to the strain, so that the flowing current changes. This can be converted into a digital electric signal, and the tensile load applied to the load button can be measured. In addition, when a compressive load acts on the load button, the compressive load can be measured similarly.

An attachment member 36 having a ring portion 36A is attached to the load button of the load cell 34. The ring portion 36A has a claw portion 40 of a separation device 38 described later.
Is hooked.

Here, the configuration of the separating device 38 will be described.

As shown in FIG. 3A, the separating device 38
Is a claw portion 4 to be hooked on the ring portion 36A of the mounting member 36.
0 is provided. The claw portion 40 is rotatably provided at one end of the cutting device main body 42. A ring 42A is formed at the other end of the cutting device main body 42.

A separating lever 44 is rotatably mounted by a shaft 46 at substantially the center of the separating device main body 42 so as to sandwich the separating device main body 42 from both sides.

A shaft 48 is provided at one end of the separation lever 44 so as to pass therethrough.
When the operator pulls 8 in the direction of arrow B in FIG. 3, the separation lever 44 rotates around the shaft 46.

Further, another shaft 50 is provided through the other end of the separation lever 44, and when the separation lever 44 is returned in the direction opposite to the arrow B direction in FIG. It comes into contact (lock) with the tip of the claw 40 and the claw 4
0 cannot be rotated with respect to the cutting device main body 42.

As shown in FIGS. 1 and 2, a piston 32A constituting the hydraulic cylinder 32 is attached to a ring 42A of the cutting device main body 42. The reciprocating linear movement of the piston 32A by the hydraulic pressure inside the cylinder body 32B allows the movable table 26 to move on the rail 24 in the horizontal direction (the direction of arrow C in FIG. 1). The cylinder body 32B is mounted and fixed on a base 52 provided on the base 22.

An acceleration sensor 54 is mounted on the lower surface plate 28B of the movable base body 28.

The acceleration sensor 54 may be a conventionally known sensor (not shown), such as a spring having a damping function, a mass system (acceleration transducer (AS-2GA), called a seismic system, manufactured by Kyowa Dengyo Co., Ltd.). used. This makes it possible to measure the acceleration of the movable base 26 that undergoes damped vibration.

Next, the tire damping coefficient measuring device 10
A method of measuring a tire damping coefficient using the method will be described.

First, an acceleration measuring method for measuring the acceleration of the movable base 26 will be described.

As shown in FIGS. 1 and 2, an OR rim assembled to a shaft 18 provided on a carriage of the side wall frame 14 is provided.
The tire 20 is mounted. Installation of OR tire 20
As described above, the OR tire 2 is attached to one shaft 18A.
After fitting the rim fitted with 0, the other shaft is connected.

Next, the base 22 is arranged on a plane between the side wall frames 14. At this time, it is preferable to arrange the moving table 26 so as to be parallel to the moving direction of the moving table 26 (direction of arrow C in the figure) and a plane passing through the axis of the OR tire 20.

Here, as shown in FIG.
When measuring the damping coefficient in the front-rear direction of 0 (tire circumferential direction), the base 22 is arranged so that the movable base 26 can move along the circumferential direction of the OR tire 20. Further, the OR tire 20 is disposed so as to contact the upper surface plate 28A of the movable base body 28.

Next, the bogie is moved downward so that a predetermined load acts on the OR tire 20 under the control of the control device. When the carriage moves downward, the OR tire 20 attached to the shaft 14 is pressed against the upper surface plate 28A of the carriage base 28 with a predetermined pressing force. This allows
A load corresponding to the type (size) of the tire can be applied to the OR tire 20, and a state in which a load similar to a real vehicle is applied to the OR tire 20 can be created.

Next, with the OR tire 20 pressed against the upper surface plate 28A of the carriage base 28, the hydraulic cylinder 32
Is linearly moved in the horizontal direction (the direction of arrow C in FIG. 1). Thereby, the movable base 26 moves on the rail 24 in the direction of arrow C.

The tensile force for pulling the movable table 26 can be measured by the load cell 34, and the linear movement of the piston 32A is hydraulically controlled so as to have a predetermined tensile force. At this time, the OR tire 20 pressed against the upper plate 28A is elastically deformed.

Next, with the movable table 26 being pulled by the hydraulic cylinder 32, the operator pulls the release lever 44 in the direction of arrow B in FIG. 3 to release the lock of the claw portion 40.

As shown in FIG. 3B, when the lock of the claw portion 40 is released, the claw portion 40 rotates with respect to the cutting device main body 42 by the pulling force from the movable table 26.

At this time, the claw portion 40 of the cutting device 42 is disengaged from the ring 36A of the mounting member 36, and the movable base 26 moves on the rail 24 in the horizontal direction (the direction indicated by the arrow C in FIG. 1) by the elastic force of the OR tire 20. Move in the opposite direction).

Here, the acceleration of the carriage 26 is measured by the acceleration sensor 54 attached to the carriage main body 28. Note that the acceleration of the moving table 26 at the moment when the moving table 26 is separated by the separating device 38 is zero.

Next, the carriage 2 which has been separated by the separating device 38 and has moved on the rail 24 in the direction opposite to the direction of arrow C.
6 stops on the rail 24 soon, and further moves on the rail 24 in the direction of arrow C by the elastic force of the OR tire 20.

Here, similarly, the acceleration of the movable platform 26 is measured by the acceleration sensor 54. The acceleration at the moment when the moving table 26 stops on the rail 24 is zero.

In this way, the moving table 26 is
The damping vibration occurs above, and the acceleration of the moving table 26 at that time is measured by the acceleration sensor 54.

As described above, the operation of measuring the acceleration of the movable base 26 is continued until the movable base 26 stops moving on the rail 24.

Thereafter, the result of measurement by the acceleration sensor 54 is output by an output device (not shown). After output,
The variation value of the acceleration is measured, and a damping coefficient in the front-rear direction (tire circumferential direction) of the OR tire 20 is calculated by a method described later.

In the present embodiment, the case where the damping coefficient of the OR tire 20 in the front-rear direction (tire circumferential direction) is measured, but the damping coefficient of the OR tire 20 in the lateral direction (tire axial direction) is measured. You can also.

In this case, as shown in FIG. 6, the base 22 is arranged so that the movable base 26 can move in a direction perpendicular to the circumferential direction of the OR tire 20.

Then, similarly, the movable base 26 is pulled by the hydraulic cylinder 32 and separated by the separating device 38, so that the movable base 26 is substantially perpendicular to the circumferential direction of the OR tire 20 (arrow C in FIG. 6). (Direction) on the rail 24 and undergoes damped vibration.

Then, similarly, the acceleration of the movable platform 26 is measured by the acceleration sensor 54, and the OR
A lateral damping coefficient of the tire 20 is calculated.

Here, in order to measure the lateral damping of the tire, the tire sizes 26.5R25, 23.5R2
FIG. 4 shows measurement results obtained when the OR tires 20 of No. 5, 23.5-25 were arranged as shown in FIG. 6 and an acceleration measurement test was performed.

FIG. 4 is a graph showing the relationship between acceleration and time, with the vertical axis representing acceleration (m / S ² ) and the horizontal axis representing time (S). As shown in FIG. 4, various OR tires drew substantially the same curve.

Here, the acceleration is determined as follows:
4, the value of the acceleration sensor 54 when moving in the direction opposite to the arrow C direction in FIG.
The value of the acceleration sensor 54 when moving upward in the direction of arrow C, which is the opposite direction, is shown on the graph as a negative value.

Next, a method of calculating a tire damping coefficient will be described.

Using a graph (see FIG. 4) showing the relationship between the acceleration measured by the method for measuring the acceleration of the OR tire and time (see FIG. 4), G1 to G6 are read from this graph, and as shown in FIG. Y) = (G2, G1), (G3,
G4),..., (G5, G6): General formula (G _N ,
G _N−1 ) and (N ≧ 2) are plotted on an XY coordinate system.

Here, G1 shown in FIG. 4 will be described below.

First, from the moment when the moving table 26 is separated by the separating device 38, the moving table 26 moves on the rail 24 as shown in FIG.
Considering the first cycle from moving in the direction opposite to the direction of the middle arrow C and stopping on the rail 24, the rail 24 starts moving from the moment when the movable table 26 moves on the rail 24 in the direction of arrow C.
The above-mentioned stop is considered as the second cycle. Similarly, the time from the moment when the moving table 26 moves on the rail 24 in the direction opposite to the direction of arrow C to the time when it stops on the rail 24 is 3 seconds.
In the cycle, the moving table 26 moves on the rail 24 with the arrow C
The period from the moment of movement in the direction to the stop on the rail 24 is considered as the fourth cycle. In this way, in the odd-numbered cycle, the carriage 26 moves in the direction opposite to the direction of arrow C,
In the even-numbered cycle, the moving table 26 moves in the direction of arrow C.

Here, G1 means the difference (fluctuation difference) between the minimum acceleration in the second cycle and the maximum acceleration in the third cycle.

G2 means the difference (fluctuation difference) between the minimum acceleration in the fourth cycle and the maximum acceleration in the fifth cycle.

Similarly, G6 means the difference (fluctuation difference) between the minimum acceleration in the 12th cycle and the maximum acceleration in the 13th cycle.

It is assumed that the movable table 26 stops on the rail 24 without damping vibration at the 13th cycle.

As described above, (G _N , G _N−1 ), (2 ≦ N
≦ 6) is plotted on the XY coordinate system, a straight line 1 connecting the plotted points is drawn, and the slope of the straight line 1 is obtained, whereby a lateral damping coefficient (attenuation coefficient) of the OR tire 20 is obtained.

As described above, according to the tire damping coefficient measuring device 10 of the present invention, it is possible to measure the damping coefficient in the lateral direction (tire axial direction) of the OR tire 20.

In the configuration shown in FIG. 1, the damping coefficient in the front-rear direction (tire circumferential direction) of the OR tire 20 can be measured in the same manner.

In the present embodiment, the moving table 26 against which the OR tire 20 is pressed is pulled by the hydraulic cylinder 32 to attenuate the vibration of the moving table 26. However, the present invention is not limited to this.

For example, although not shown, the moving table is fixed on a rail, and a shaft and a truck for fixing the rim-assembled OR tire and pressing it against the moving table are provided so as to be movable in the horizontal direction. After the sensor is mounted, the shaft may be pulled horizontally by a hydraulic cylinder, cut off, and the shaft and the OR tire may be damped. Also in this configuration, after measuring the acceleration of the OR tire, the damping coefficient of the OR tire can be calculated by the same method as described above.

[0098]

According to the tire damping coefficient measuring apparatus of the present invention, it is possible to measure the damping property of a large tire such as a tire for a construction vehicle.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a state in which a tire is pressed against a tire damping coefficient measuring device according to an embodiment of the present invention in order to measure a damping coefficient in a front-rear direction of the tire.

FIG. 2A is a plan view of a tire damping coefficient measuring device according to an embodiment of the present invention, and FIG. 2B is a side view thereof.

FIG. 3 is an operation diagram of a separating device included in the tire damping coefficient measuring device according to one embodiment of the present invention.

FIG. 4 is a graph showing the relationship between the acceleration of the moving base and time measured by the tire damping coefficient measuring device of the present invention.

FIG. 5 is a graph showing a variation in tire acceleration in an XY coordinate system.

FIG. 6 is a configuration diagram illustrating a state in which a tire is pressed against a tire damping coefficient measurement device according to an embodiment of the present invention in order to measure a lateral damping coefficient of the tire.

FIG. 7 is a partial side view of a movable base included in the tire damping coefficient measuring device according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 tire damping coefficient measuring device 20 OR tire (tire) 26 moving table (moving member, supporting member) 29 protrusion (friction increasing means) 32 hydraulic cylinder (traction member) 34 load cell (measuring member) 38 separating device (separating) 54) Acceleration sensor (acceleration measuring device)

Claims (7)

[Claims] 1. A moving member movable in one direction, a traction member for pulling the moving member pressed with a fixed tire in one direction, and a separating member for disconnecting a connection between the moving member and the traction member. And an acceleration measuring device attached to the moving member, the acceleration measuring device measuring the acceleration of the moving member which has been disconnected in connection with the traction member and has attenuated and vibrated in one direction. Damping coefficient measuring device. 2. The tire damping coefficient measuring device according to claim 1, further comprising a measuring member for measuring a tensile force of the traction member. 3. The tire damping according to claim 1, wherein a friction increasing means for increasing friction with the tire is provided on a contact surface of the moving member against which the tire is pressed. Coefficient measuring device. 4. The tire damping coefficient measuring device according to claim 1, wherein the traction member is a hydraulic cylinder. 5. The tire damping coefficient measuring device according to claim 2, wherein the measuring member is a load cell. 6. The tire damping coefficient measuring device according to claim 1, further comprising a load device that fixes the tire and presses the tire against the moving member. 7. A load member which is provided so as to be movable in one direction with a support member, fixes a tire and presses the tire against the support member with a predetermined load, and the tire is pressed against the support member. A traction member that pulls the load load device in one direction in a state, a disconnecting member that disconnects the connection between the load load device and the traction member, and a connection between the load load device or the tire and the traction member. A tire damping coefficient measuring device, comprising: an acceleration measuring device for measuring the acceleration of the tire, which has been separated and damped in one direction.