JP7747677B2 - Rolling device and rolling method - Google Patents

Description

The present invention relates to a rolling device and a rolling method for compacting asphalt mixtures.

The tire rollers that compact the asphalt mixture laid on the roadbed generally have three front wheels arranged in the left-right direction and four rear wheels arranged in the left-right direction, as described in JP 2022-76577 A (Patent Document 1).

Japanese Patent Application Laid-Open No. 2022-76577

Sloped surfaces such as those found on automobile test courses are often curved slopes (curved surfaces) that gradually increase in gradient from the bottom to the top. When compacting asphalt mixture paved on a curved surface using a conventional tire roller, the undersides of the front and rear wheels do not line up with the curved surface, which can reduce the accuracy of compacting the asphalt mixture. For this reason, tilting the front and rear wheels of the tire roller to match the curved surface is one option, but this makes it difficult to further improve the accuracy of compacting asphalt mixture paved on curved surfaces, particularly because the rolling load acting on each of the three front wheels is not necessarily uniform.

The present invention aims to provide a rolling device and rolling method that can equalize the rolling load acting on multiple front and rear wheels, thereby improving the compaction accuracy of asphalt mixtures laid on curved surfaces.

The rolling compaction device has a vehicle body, three front wheels arranged laterally at the front of the vehicle body, four rear wheels arranged laterally at the rear of the vehicle body, a front wheel support device that supports the three front wheels relative to the vehicle body, and a rear wheel support device that supports the four rear wheels relative to the vehicle body. The front wheel support device has a first link member whose middle portion is fixed to the vehicle body so as to be swingable about a first swing shaft extending in the fore-and-aft direction, and in which a front wheel is supported at a first distance on one side of the left and right from the first swing shaft, and a second link member whose middle portion is fixed to a second distance (half the first distance) on the other side of the first swing shaft so as to be swingable about a second swing shaft extending in the fore-and-aft direction, and in which a front wheel is supported at a second distance on both sides of the second swing shaft in the left and right direction. The rear wheel support device also has a third link member whose middle section is fixed to the vehicle body, and two fourth link members whose middle sections are fixed to positions spaced a third distance on both sides in the left-right direction from the fixed point of the third link member to the vehicle body so that they can swing around a third swing axis extending in the fore-and-aft direction, and on which rear wheels are supported at positions spaced a fourth distance on both sides in the left-right direction from the third swing axis.

In addition, in a rolling compaction method, such a rolling compaction device is used, and the vehicle body functions as a weight to swing the first and second link members of the front wheel support device and the fourth link member of the rear wheel support device, respectively, and the asphalt mixture paved on the curved slope is compacted while the front and rear wheels are displaced to follow the curved slope.

This invention makes it possible to equalize the rolling load acting on the multiple front and rear wheels of a rolling device, thereby improving the compaction accuracy of asphalt mixtures laid on curved surfaces.

FIG. 2 is a side view showing an example of a pneumatic tire roller. FIG. 2 is a front view showing an example of a pneumatic tire roller. FIG. 2 is a rear view showing an example of a pneumatic tire roller. FIG. 2 is a plan view showing an example of a front wheel support device. FIG. 2 is a front view showing an example of a front wheel support device. FIG. 2 is an explanatory diagram of a link mechanism formed by the front wheel support device. 10A and 10B are explanatory diagrams illustrating the action of the front wheel support device. FIG. 2 is a plan view showing an example of a rear wheel support device. FIG. 2 is a rear view showing an example of a rear wheel support device. FIG. 2 is an explanatory diagram of a link mechanism formed by the rear wheel support device. 5A and 5B are explanatory diagrams illustrating the operation of the rear wheel support device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1 to 3 show an example of a tire roller 100 for compacting an asphalt mixture, which can be given as an example of a rolling device that can be used in this embodiment.

The tire roller 100 comprises a vehicle body 200 equipped with a drive unit such as a diesel engine or electric motor and capable of functioning as a weight; three front wheels 300 arranged at equal intervals in the left-right direction at the front of the vehicle body 200; four rear wheels 400 arranged at equal intervals in the left-right direction at the rear of the vehicle body 200; a front wheel support device 500 that supports the three front wheels 300 steerably relative to the vehicle body 200; and a rear wheel support device 600 that supports the four rear wheels 400 drivably relative to the vehicle body 200. Here, the front wheels 300 and rear wheels 400 can be, for example, pneumatic rubber tires to suppress noise generated during compaction work.

The drive unit mounted on the vehicle body 200 drives a hydraulic pump to generate hydraulic pressure, which serves as a working fluid, and supplies hydraulic pressure to a hydraulic actuator (not shown) for steering the front wheels 300 and a hydraulic motor (not shown) for rotating the rear wheels 400. A driver's seat 220 for operating the pneumatic tire roller 100 is attached to a predetermined location on top of the vehicle body 200. The driver's seat 220 includes a seat 220A for the operator, a steering wheel 220B for steering, a control panel 220C equipped with pedals, levers, switches, and instruments, and a canopy 220D. In the pneumatic tire roller 100 shown in Figures 1 to 3, the driver's seat 220 is attached only to the right side of the vehicle body 200, but driver's seats 220 may also be attached to both the left and right sides of the vehicle body 200.

As shown in Figures 4 and 5, the front wheel support device 500 has a first link member 520 whose middle portion is fixed to the vehicle body 200 so as to be swingable about a first swing axis SS1 extending in the fore-and-aft direction, and a second link member 540 whose middle portion is fixed so as to be swingable about a second swing axis SS2 extending in the fore-and-aft direction. The first link member 520 supports the front wheel 300 at a position separated by a first distance L1 in one direction from the first swing axis SS1. The second link member 540 has a middle portion swingably fixed at a position separated by a second distance L2, which is half of the first distance L1, in the other direction from the first swing axis SS1 of the first link member 520. Additionally, the second link member 540 supports the front wheels 300 at positions spaced a second distance L2 on both left and right sides of the second swing shaft SS2. Here, it is desirable that the first swing shaft SS1 be located in the center of the vehicle body 200 in the left-right direction.

Specifically, the first link member 520 has a roughly U-shaped frame in plan view, which is integrated by welding or other means. The vertical member 522 extends in the fore-and-aft direction beyond the diameter of the front wheel 300 on one side of the vehicle body 200 (the right side in the illustrated example), and two horizontal members 524 are arranged to extend perpendicularly and parallel from both ends of the vertical member 522 toward the other side of the vehicle body 200 (the left side in the illustrated example). The middle portions of the two horizontal members 524 are fixed via a first swing shaft SS1 to the tip of the steering arm 240 of the vehicle body 200 so as to be swingable within a predetermined angular range.

The second link member 540 has a roughly rectangular frame in plan view, which is integrated by welding or other means. The two vertical members 542 extend in the fore-and-aft direction beyond the diameter of the front wheel 300, located on the other side of the vehicle body 200 and outside the front wheel 300, which is located in the left-right center of the vehicle body 200. The two horizontal members 544 extend perpendicularly and parallel in the left-right direction to connect the ends of the two vertical members 542. The middle portions of the two horizontal members 544 are fixed to the two horizontal members 524 of the first link member 520 via the second swing shaft SS2 so as to be swingable within a predetermined angular range.

In the first link member 520, two horizontal members 524 are located between the first swing axis SS1 and the vertical member 522, and are spaced a first distance L1 from the first swing axis SS1 in either the left-right direction. The front wheel 300, located on one side of the vehicle body 200, is supported at these positions so that it can swing within a predetermined angular range around the swing axis SS (fourth swing axis) extending in the fore-and-aft direction. In other words, the front wheel 300 is rotatably attached to a frame member 526 that is rectangular in plan view around a rotation axis RS that extends in the left-right direction, and the front and rear portions of the frame member 526 are attached to the two horizontal members 524 of the first link member 520 via the swing axis SS. Therefore, the front wheel 300 located on one side of the vehicle body 200 can further swing around the swing axis SS extending in the fore-and-aft direction relative to the first link member 520.

In the second link member 540, two front wheels 300, one on the other side and one in the center of the vehicle body 200, are supported at two positions spaced a second distance L2 on both sides of the second swing axis SS2 of the two cross members 544. Of these two front wheels 300, the front wheel 300 located on the other side of the vehicle body 200 is rotatably mounted around a rotation axis RS extending in the left-right direction relative to a frame member 546 that is rectangular in plan view, similar to the front wheel 300 located on one side of the vehicle body 200. Furthermore, portions located in front and behind the frame member 546 are attached to the two cross members 544 of the second link member 540 via a swing axis SS (fourth swing axis). Therefore, the front wheel 300 located on the other side of the vehicle body 200 can further swing around the swing axis SS extending in the fore-and-aft direction relative to the second link member 540.

Here, since the three front wheels 300 are arranged at equal intervals, the first distance L1 of the first link member 520 is the spacing between the front wheels 300, and the second distance L2 of the first link member 520 and the second link member 540 is 1/2 of the spacing between the front wheels 300.

As shown in FIG. 6, the front wheel support device 500 can also be described as a link mechanism having a first link member 520 that can swing about a first swing axis SS1 that extends in the fore-and-aft direction relative to the center of the left-and-right direction of the vehicle body 200, and a second link member 540 that can swing about a second swing axis SS2 that extends in the fore-and-aft direction relative to the first link member 520. In this case, the front wheel 300 is supported at two positions on the first link member 520: one a first distance L1 to the right of the first swing axis SS1; and the other a second distance L2 on both left-and-right sides of the second swing axis SS2 on the second link member 540.

When a load W acts on the front wheel support device 500 from the vehicle body 200, because the ratio of the first distance L1 to the second distance L2 in the first link member 520 is 2:1, a load of 1/3W acts on the front wheel 300 located on the right, and a load of 2/3W acts on the second swing shaft SS2 of the second link member 540 due to moment balance. The load 2/3W acting on the second swing shaft SS2 of the second link member 540 supports the two front wheels 300 at positions equidistant from the second swing shaft SS2, the second distance L2, so due to moment balance, a load of 1/3W acts on each of the two front wheels 300. For this reason, a uniform rolling load of 1/3W acts on all three front wheels 300, preventing a large load from acting on any particular front wheel 300. Furthermore, by equalizing the rolling load acting on each front wheel 300, the compaction accuracy of asphalt mixtures laid on curved surfaces can be improved.

Of the three front wheels 300 supported by the front wheel support device 500, the two front wheels 300 positioned at the outermost positions in the left-right direction are able to swing about a swing axis SS extending in the fore-and-aft direction via frame members 526 and 546. Therefore, as shown in Figure 7, when compacting an asphalt mixture laid on a curved surface CS, the two front wheels 300 further swing due to the vertical force they receive from the curved surface CS, and attempt to become perpendicular to the curved surface CS. Therefore, the undersides of the three front wheels 300 conform to the shape of the curved surface CS, further improving the compaction accuracy of the asphalt mixture laid there.

As shown in Figures 8 and 9, the rear wheel support device 600 has a third link member 620 whose middle portion is fixed to the vehicle body 200, and two fourth link members 640 whose middle portions are fixed so as to be swingable around a third swing axis SS3 extending in the fore-and-aft direction. The two fourth link members 640 are each swingably fixed at their middle portions at positions spaced a third distance L3 on both left-right sides from a fixed point FP of the third link member 620 to the vehicle body 200. Furthermore, each fourth link member 640 supports the rear wheel 400 at a position spaced a fourth distance L4 on both left-right sides from the third swing axis SS3. Here, it is desirable that the fixed point FP of the third link member 620 to the vehicle body 200 be located in the center of the vehicle body 200 in the left-right direction.

Specifically, the third link member 620 has a rectangular frame in plan view, which is integrated by welding or the like, with two vertical members 622 extending parallel to each other in the fore-and-aft direction beyond the diameter of the two rear wheels 400 located outside the two outermost rear wheels 400 in the left-right direction, and two horizontal members 624 extending parallel to each other in the left-right direction and connecting the ends of the two vertical members 622. The intermediate portions, preferably the central portions, of the two horizontal members 624 are fixed integrally to a bracket BK1 that hangs down from a predetermined position on the rear of the vehicle body 200.

Each fourth link member 640 has a roughly U-shaped frame in plan view, which is made up of a vertical member 642 that extends in the fore-and-aft direction beyond the diameter of the rear wheel 400, located outside the outermost of the two rear wheels 400 positioned on the right or left side of the vehicle body 200, and two horizontal members 644 that extend perpendicularly and parallel from both ends of the vertical member 642 to opposite sides, integrated by welding or other means. The middle portion of each horizontal member 644 is fixed via a third swing shaft SS3 to brackets BK2 that hang down from predetermined positions on the two horizontal members 644 of the third link member 620 so as to be swingable within a predetermined angular range.

The intermediate portions of the two cross members 644 of the fourth link member 640 are each fixed via a third swing axis SS3 so as to be swingable at two positions spaced a third distance L3 on both left-right sides from the fixed point FP of the third link member 620 relative to the vehicle body 200. Furthermore, in each fourth link member 640, two rear wheels 400 located on the right or left side of the vehicle body 200 are supported at two positions spaced a fourth distance L4 on both left-right sides from the third swing axis SS3 so as to be swingable within a predetermined angular range around a swing axis SS (fifth swing axis) extending fore-aft and rearward. That is, these rear wheels 400 are rotatably attached to a frame member 646 that is rectangular in plan view, around a rotation axis RS that extends in the left-right direction, and the front and rear portions of the frame member 646 are respectively attached to the two cross members 644 of the fourth link member 640 via swing axes SS. Therefore, the four rear wheels 400 can further swing around the swing axes SS that extend in the front-to-rear direction relative to the fourth link member 640.

Here, since the four rear wheels 400 are arranged at equal intervals, the third distance L3 of the third link member 620 is the spacing between the rear wheels 400, and the fourth distance L4 of the fourth link member 640 is half the spacing between the rear wheels 400.

As shown in Figure 10, the rear wheel support device 600 can also be described as a link mechanism having a third link member 620 fixed integrally to the center of the vehicle body 200 in the left-right direction, and two fourth link members 640 that can swing around a third swing axis SS3 that extends in the fore-and-aft direction relative to the third link member 620. In this case, the two fourth link members 640 each support the rear wheel 400 at two positions separated by a fourth distance L4 in the left-right direction from the third swing axis SS3, which is the swing point relative to the third link member 620.

When a load W is applied from the vehicle body 200 to the rear wheel support device 600, the third link member 620 supports two fourth link members 640 at two positions equidistant from the fixed point FP of the third link member 620 relative to the vehicle body 200, so a load of 1/2W acts on each of the two fourth link members 640. Furthermore, when a load of 1/2W acts on the fourth link member 640, the fourth link member 640 supports the rear wheels 400 at two positions equidistant from the third swing axis SS3, so a load of 1/4W acts on each rear wheel 400 due to moment balance. For this reason, an equal rolling load of 1/4W acts on each of the four rear wheels 400, preventing a large load from acting on any particular rear wheel 400. Furthermore, by equalizing the rolling load acting on each rear wheel 400, the compaction accuracy of the asphalt mixture laid on a curved surface can be improved.

Furthermore, the four rear wheels 400 supported by the rear wheel support device 600 are able to swing around a swing axis SS extending in the fore-and-aft direction via the frame member 646. Therefore, as shown in Figure 11, when compacting the asphalt mixture paved on the curved surface CS, the four rear wheels 400 further swing due to the vertical force received from the curved surface CS, and attempt to become perpendicular to the curved surface CS. As a result, the undersides of the four rear wheels 400 conform to the shape of the curved surface CS, further improving the compaction accuracy of the asphalt mixture paved there.

Next, we will explain a rolling method for compacting an asphalt mixture paved on a curved surface CS using such a tire roller 100. Because the tire roller 100 traveling over the curved surface CS may slide downward due to gravity, to ensure safety, it is supported by a wire rope extending from a support cart placed above the curved surface CS, as in conventional technology. In this way, the wire rope supports the force along the curved surface CS, allowing the tire roller 100 to apply an even load only in the direction perpendicular to the curved surface CS.

The tire roller 100 then travels over an asphalt mixture paved on a curved surface CS, such as an automobile test course, in response to operator operation. The vehicle body 200 functions as a weight, swinging the first link member 520 and second link member 540 of the front wheel support device 500 and the fourth link member 640 of the rear wheel support device 600. As a result, as shown in Figures 7 and 11, the front wheels 300 and rear wheels 400 are displaced to conform to the curved surface CS, and their undersides assume a posture conforming to the curved surface CS. When the tire roller 100 travels in this state, because the undersides of the front wheels 300 and rear wheels 400 are oriented to conform to the curved surface CS, the undersides of, for example, a particular front wheel 300 or rear wheel 400 do not deviate from the cross-sectional shape of the curved surface CS, improving the compaction accuracy of the asphalt mixture.

The tire roller 100 described above is merely one embodiment for implementing the present invention, and the present invention should not be construed as being limited to this tire roller 100. Therefore, it will be readily understood that rolling devices such as tire rollers that can be easily imagined from the above embodiment are included in the present invention.

A person skilled in the art will readily understand that new embodiments can be created by omitting parts of the technical ideas of the various embodiments described above, combining parts as appropriate, or replacing parts with well-known technology.

100 Tire roller (rolling device)
200 Vehicle body 300 Front wheel 400 Rear wheel 500 Front wheel support device 520 First link member 526 Frame member 540 Second link member 546 Frame member 600 Rear wheel support device 620 Third link member 640 Fourth link member 646 Frame member CS Curved surface (curved slope)
FP Fixed point L1 First distance L2 Second distance L3 Third distance L4 Fourth distance SS Swing axis (fourth swing axis, fifth swing axis)
SS1 First swing axis SS2 Second swing axis SS3 Third swing axis

Claims (7)

The car body and
three front wheels arranged in the left-right direction at the front of the vehicle body;
four rear wheels arranged in the left-right direction at the rear of the vehicle body;
a front wheel support device that supports the three front wheels with respect to the vehicle body;
a rear wheel support device that supports the four rear wheels with respect to the vehicle body;
A rolling device having
The front wheel support device comprises: a first link member, the first link member having a middle portion fixed to the vehicle body so as to be swingable about a first swing shaft extending in the longitudinal direction, and the front wheel being supported at a position spaced a first distance from the first swing shaft on one side in the left-right direction; and a second link member, the first link member having a middle portion fixed to a position spaced a second distance, which is half the first distance, from the first swing shaft on the other side in the left-right direction so as to be swingable about a second swing shaft extending in the longitudinal direction, and the front wheels being supported at positions spaced the second distance on both sides in the left-right direction from the second swing shaft,
The rear wheel support device includes a third link member having an intermediate portion fixed to the vehicle body, and two fourth link members having intermediate portions fixed to positions spaced a third distance on both sides in the left-right direction from a fixed point of the third link member to the vehicle body so as to be swingable about a third swing shaft extending in the front-rear direction, and supporting the rear wheels respectively at positions spaced a fourth distance on both sides in the left-right direction from the third swing shaft.
Rolling compaction equipment. The fixing point of the third link member to the first swing shaft and the vehicle body is located at the center of the vehicle body in the left-right direction.
The rolling device according to claim 1. The three front wheels are arranged at equal intervals,
the first distance of the first link member is equal to the spacing between the front wheels, and the second distance of the first link member and the second link member is equal to half of the spacing between the front wheels;
The rolling device according to claim 1. The four rear wheels are arranged at equal intervals,
the third distance of the third link member is an arrangement interval of the rear wheels,
the fourth distance of the fourth link member is half the spacing between the rear wheels;
The rolling device according to claim 1. two front wheels disposed outermost in the left-right direction among the three front wheels are supported by the first link member and the second link member, respectively, so as to be swingable about a fourth swing shaft extending in the front-rear direction;
The rolling device according to claim 1. the four rear wheels are supported by the fourth link member so as to be swingable about fifth swing shafts extending in the front-rear direction;
The rolling device according to claim 1. A rolling method using the rolling device described in any one of claims 1 to 6, using the vehicle body as a weight to swing the first link member and the second link member of the front wheel support device and the fourth link member of the rear wheel support device, respectively, and displacing the front wheels and the rear wheels to follow the curved slope, while compacting the asphalt mixture paved on the curved slope.