JP4807556B2 - tire - Google Patents

Description

  The present invention relates to a tire suitable for traveling on rough terrain with rubble or road surfaces with steps.

Patent Document 1 discloses a low-pressure pneumatic tire for running on rough terrain. This tire is formed by protruding a large number of tread portions on the outer periphery. In a wheel equipped with this tire, the tire deforms in accordance with the shape of the rough terrain, so that the grip force is increased and the running performance is improved. In addition, the tread portion is caught by rubble and can be overcome.
JP-A-1-148606

  However, the wheel equipped with the tire of Patent Document 1 could not get over a high step. That is, since the tread portion that reaches the step first hits the side surface of the step, the wheel does not approach the step any more, and the next tread portion does not get caught on the upper end of the high step.

  If the circumferential interval between the tread portions is increased, the tread portion that has reached first moves downward and leaves the step, so that the wheel approaches the step and the next tread portion is hooked on the upper end of the step. Therefore, as the circumferential interval between the tread portions is increased, the wheel can get over a higher level difference.

  However, when the interval between the tread portions is increased, the traveling becomes unstable and the vibration during traveling increases when the wheel travels on a flat road surface. Furthermore, it is impossible to increase the distance between the tread portions so that a step larger than the tire radius can be overcome, because the instability of the wheel running exceeds the allowable limit.

  The present invention has been made to solve the above problems, and in a rubber tire having an annular base portion and a plurality of tread portions having the same height and projecting from the outer periphery of the base portion, The tread portion includes at least two types of tread portions, a first tread portion and a second tread portion, and a second tread portion is disposed between the first tread portions separated in the circumferential direction, and the first tread portion has bending rigidity. The second tread portion has a low bending rigidity and is easily bent in the tire circumferential direction.

  When the wheel equipped with the tire configured as described above hits the step, the second tread portion is elastically deformed so that it bends, so the wheel can be brought close to the step, and even if the step is equal to or greater than the radius of the tire, One tread portion can be hooked on the upper end of the step. As a result, the wheel can get over high steps. In addition, when the wheel travels on a flat road surface, the second tread portion disposed between the first tread portions bears a load in the same manner as the first tread portion, so that the wheel travels stably and vibrations occur. Can be suppressed.

Preferably, the circumferential thickness of the second tread portion is thinner than that of the first tread portion.
Preferably, the second tread portion can be bent in the tire circumferential direction until the second tread portion has a height of 1/3 to 2/3 as compared with a height in a non-bent state.

  Preferably, each of the first and second tread portions has a trapezoidal shape in a vertical cross section along a plane orthogonal to the central axis of the tire, and a bottom side of the second tread portion is thinner than a bottom side of the first tread portion. This trapezoidal cross-sectional shape provides a taper when the tread portion is formed.

  Preferably, the second tread portion extends in the tire width direction, and a planar shape thereof is bent. According to this, the load bearing capacity of the second tread portion can be increased.

  Preferably, a plurality of the second tread portions are arranged between the first tread portions. According to this, traveling stability can further be improved. Moreover, it can drive | work without slipping by gripping debris etc. with a some 2nd tread part.

  Preferably, all the first tread portions are arranged at equal intervals in the circumferential direction. According to this, the running performance of the wheel can be further stabilized.

Preferably, the outer periphery of the base portion has two annular regions adjacent to each other in the width direction, and in the two annular regions, the first and second tread portions are arranged out of phase in the same pattern. Between the first tread portion and the first tread portion of the other annular region, second tread portions are respectively disposed in both annular regions.
According to this, the distance between the second tread portion of one annular region and the first tread portion of the other annular region can be narrowed without hindering the bending of the second tread portion, and the running stability can be reduced. Can be further enhanced.

  Preferably, a plurality of second tread portions are respectively arranged in the annular regions so as to be shifted in the circumferential direction between the first tread portion of the one annular region and the first tread portion of the other annular region. . According to this, traveling stability can further be improved.

  Preferably, the second tread portion of the other annular region is arranged next to the first tread portion in the width direction of the one annular region. According to this, traveling stability can further be improved.

Preferably, the base portion has a solid band shape. According to this, the tire becomes a solid tire, and the rolling resistance can be reduced as compared with the low pressure tire.
Preferably, the tire is attached to a wheel driven by an electric motor.

  A wheel equipped with the tire of the present invention can get over a high step without impairing running stability.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a wheel 1 used for a suspension part of a lightweight small robot for light work (for example, a total weight of 50 kg or less). The upper body of the robot has a different configuration depending on the role of the robot. For example, in the case of a rescue robot used in the event of a disaster such as an earthquake, it is equipped with a camera, a detection sensor, and a lighting fixture, and is equipped with a lightweight object gripping mechanism as necessary. Such a rescue robot travels over rubble and searches for injured persons.

  The wheel 1 includes a wheel body 10 made of resin or light metal and a tire 20 made of rubber (may be natural rubber or synthetic rubber such as SBR or urethane). The outer periphery of the wheel body 10 forms a cylindrical surface, and a tire 20 is mounted on the outer periphery.

  The tire 20 is made of a solid tire, and includes a base portion 21 having a solid belt shape, and first and second tread portions 25 and 26 integrally formed on the outer periphery of the base portion 21. Have. The tire 20 is mounted on the wheel body 10 by bonding the base portion 21 to the outer periphery of the wheel body 10 (bonding using an adhesive or vulcanization bonding).

  The first tread portion 25 is thick, the second tread portion 26 is thin, and both tread portions 25 and 26 have the same height.

  The outer periphery of the base portion 21 has two annular regions adjacent to each other in the width direction, and the tread portions 25 and 26 are provided in these annular regions with the same pattern shifted in phase.

  More specifically, a plurality of, for example, three first tread portions 25 are formed at equal intervals in the annular region on the right side in FIG. 1, and a plurality of, for example, five second treads are provided between these first tread portions 25. The portions 26 are provided at equal intervals.

  The same number of first and second tread portions 25 and 26 are also provided in the same pattern in the left annular region. However, the arrangement pattern of the tread portions 25 and 26 in the left and right regions is shifted by 60 °, and the first tread portion 25 in the other annular region is arranged in the center between the first tread portions 25 in one annular region. ing.

  Between the first tread portion 25 of one annular region and the first tread portion 25 of the other annular region, a plurality of, for example, two second tread portions 26 are arranged for each annular region, for a total of four second tread portions. 26 is arranged. The second tread portion 26 of one annular region and the second tread portion 26 of the other annular region are shifted in the circumferential direction by a half of the circumferential interval of the second tread portion 26 of each annular region.

  Next to the first tread portion 25 in the width direction of one annular region, the second tread portion 26 of the other annular region is disposed.

  The arrangement pattern of the first and second tread portions 25 and 26 can also be expressed as follows. The base portion 21 has first and second regions alternately along the circumferential direction. In the first region, the first tread portion 25 and the second tread portion 26 are arranged adjacent to each other in the width direction (left-right direction). In the second region, four second tread portions 26 are alternately arranged on the left and right sides while shifting their positions in the circumferential direction.

  The first tread portion 25 extends in the width direction of the wheel 1 and has a vertical cross-sectional shape (a vertical cross-sectional shape along a plane orthogonal to the central axis of the wheel 1) having a trapezoidal shape. Since the first tread portion 25 has a large bottom dimension, the bending rigidity is sufficiently high, and the first tread portion 25 does not bend even when a force in the circumferential direction of the wheel 1 is applied.

  The second tread portion 26 also extends in the width direction of the crawler belt 20 and has a trapezoidal longitudinal cross-sectional shape. Since the thickness of the second tread part 26 is much smaller than the height, the bending rigidity is much smaller than that of the first tread part 25, and the second tread part 26 is easily bent when a circumferential force is applied to the tread part 26.

The height of the second tread portion 26 is preferably not less than 2 times and not more than 7 times, more preferably not less than 3 times and not more than 5 times the thickness (average thickness or thickness of the central portion in the height direction). It is as follows. The planar shape of the tread portion 26 is a “<” shape that is folded at the center as shown in FIG. 1. This increases the strength against the load in the height direction, that is, the robot's own weight.
The height of the tread portions 25 and 26 is preferably 10 to 30% with respect to the tire outer diameter.
The occupation ratio of the first and second tread portions 25 and 26 with respect to the peripheral surface of the base portion 21 is 60% or less, preferably 50%, and the second tread portion 26 is adjacent to the tread portions 25 and 26 in the circumferential direction. On the other hand, it is separated by at least the bottom thickness, and the bending performance described later is guaranteed.

An example of the dimension of each component in this embodiment will be described. The radius of the wheel body 10 is 50 mm to 75 mm, the thickness of the base portion 21 is about 3 mm, the bottom thickness of the cross-sectional shape of the first tread portion 25 is 15 mm, the top thickness is 4 mm, and the height is 20 mm. The cross-sectional shape of the second tread portion 26 has a bottom thickness of 5 mm, a top thickness of 3 mm, and a height of 20 mm.
The radius R (see FIG. 2) of the tire 20 is preferably 150 mm or less, and more preferably about 70 to 100 mm.
Since the base portion 21 is solid and thinner than the tread portions 25 and 26, the weight can be reduced.

  The robot includes, for example, four wheels 1 configured as described above. The load that each wheel 1 bears on flat ground is preferably 10 kg or less. When all the wheels 1 are driven to rotate by driving an electric motor (actuator) (not shown) (when the front wheel 1 is driven to rotate in the case of front wheel driving), the robot travels. As shown in FIG. 2, the wheel 1 can get over a step S higher than the radius R of the wheel 1 (the height of the step is indicated by a symbol H).

  More specifically, when the wheel 1 of the robot hits the step S, the tip of the second tread portion 26 hits the step S. The second tread portion 26 rotates in the direction of rotation along with the rotation of the wheel 1 in the arrow direction. It begins to bend under the force of the opposite direction, and further bends as the robot advances. In this state, since the top end portion of the first tread portion 25 is caught on the upper end of the step S, the robot can get over the high step S. The second tread portion 26 can be bent in the tire circumferential direction until the height becomes 1/3 to 2/3 of the height in the unfolded state. In this embodiment, it can be bent to about half the height.

As described above, the function of overcoming the high step S can be obtained in the same manner even when the second tread portion 26 is not provided and the first tread portion 25 is spaced by 60 ° in the circumferential direction. However, in such a case, since the interval between the first tread portions 25 is large, the traveling of the wheel 1 becomes unstable and the vibration becomes large especially when traveling on a flat road surface.
In the present embodiment, a plurality of second tread portions 26 having the same height as the first tread portion 25 are arranged between the first tread portions 25 and can bear the load of the robot. it can.

  The second tread portion 26 is easy to bend but has sufficient strength against the load in the height direction, that is, the weight of the robot, and can ensure smooth running without being greatly deformed. In addition, since the tread portion 26 has a shape in which the planar shape is bent, it is possible to further increase the load capacity with respect to the vertical load.

  In the present embodiment, a plurality (four) of the second tread portions 26 are disposed between the first tread portions 25, the second tread portions 26 are alternately disposed on the left and right sides, and the first tread portion 25. Since the second tread portion 26 is disposed adjacent to the width direction of the wheel 1, the traveling of the wheel 1 can be further stabilized.

  Further, as shown in FIG. 2, when viewed from the side, the first tread portion 25 and the second tread portion 26 adjacent thereto are arranged close to each other, and this arrangement also contributes to the running stability of the wheel 1. is doing.

  As described above, if the second tread portion 26 is too close to the first tread portion 25, it is considered that the bending near the bottom of the second tread portion 26 may be hindered. This is because the base portion 21 connected to the bottom portion of the second tread portion 26 is restrained by the first tread portion 25. However, in the present embodiment, since the first tread portion 25 and the second tread portion 26 are arranged in different annular regions, the first tread portion 25 becomes the second tread when the second tread portion 26 is bent. The second tread portion 26 is bent well without restraining the base portion 21 in the vicinity of the portion 26.

Moreover, in this embodiment, since the several 2nd tread part 26 is arrange | positioned between the 1st tread parts 25, it adjoins with respect to the comparatively low debris S 'which has a flat surface like FIG. 3, for example. The second tread portion 26 to be elastically deformed can be gripped with a large contact area, and the idling of the wheel 1 can be avoided. This function works particularly effectively when the debris S ′ is wet or sand is attached.
On the other hand, the first tread portion 25 has a grip function higher than that of the second tread portion 26 for an obstacle such as a pipe having a curved cross section.

FIG. 4 shows a second embodiment of the present invention. In this embodiment, components corresponding to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The outer periphery of the base portion 21 of the present embodiment is not divided into two in the width direction, and the tread portions 25 and 26 extend to the full width of the base portion 21. The first tread portions 25 are arranged at regular intervals (for example, 90 °) in the circumferential direction, and a plurality of, for example, three second tread portions 26 are arranged at intervals between the first tread portions 25. .
In the second embodiment, the running stability is inferior to that in the first embodiment, but other functions such as overcoming a high step are the same as those in the first embodiment.

  The mounting method of the tire 20 in the first and second embodiments will be illustrated. In the first mounting method, a tire material having a length corresponding to the entire circumference of the wheel body 10 is formed by injection molding or the like. This tire material integrally has an elongated strip-like base portion 21 and first and second tread portions 25 and 26 extending linearly. Next, the base portion 21 is bonded so as to be wound around the outer periphery of the wheel body 10. At this time, both ends of the base portion 21 are matched.

  In the second mounting method, the tire 20 is vulcanized and bonded over the entire circumference of the wheel body 10.

  The third mounting method forms a plurality of tire materials. These tire materials integrally include a base portion 21 having a length obtained by equally dividing the entire circumferential length of the wheel body 10 and first and second tread portions 25 and 26. And it adhere | attaches on the outer periphery of the wheel main body 10 so that the base part 21 of a tire raw material may be spliced together. In the third mounting method, the plurality of tire materials may be vulcanized and bonded to the outer periphery of the wheel body 10 in order.

  In the fourth mounting method, a tire material having the base portion 11 and the tread portions 25 and 26 is fixed to a plurality of arc-shaped attachments that match the outer periphery of the wheel body 10 by bonding or vulcanization bonding, and this attachment is fixed. The wheel body 10 is mounted with bolts and nuts. According to the fourth mounting method, the tire 20 can be replaced when worn.

The present invention is not limited to the above embodiment, and various aspects can be adopted. The planar shape of the second tread portion 26 may be bent at a plurality of locations to have a waveform. The second tread portion 26 may be formed to have a uniform thickness instead of a trapezoidal cross section.
In the first and second regions that are divided and arranged alternately in the circumferential direction, a plurality of, for example, two tread portions may be arranged in the first region at short intervals.
You may arrange | position another tread part with the said 2nd tread part between 1st tread parts. The other tread portion is thinner than the first tread portion and thicker than the second tread portion.

  The present invention can also be applied to a normal pneumatic tire. In this case, the base portion has an internal space and has an inverted U-shaped cross section.

  The wheel of the present invention may be used for lightweight robots for hospital cleaning, security, etc. in addition to the lifesaving robot. Even in this case, it is effective when traveling on a road surface with steps. Moreover, you may use for lightweight construction machines and lightweight vehicles other than a robot.

It is a perspective view of a wheel provided with a tire which makes a 1st embodiment of the present invention. It is a side view which shows the state when the wheel gets over a high level | step difference. It is a principal part enlarged view which shows the grip state by the 2nd tread part when the wheel is drive | working the low rubble. It is a perspective view of the wheel provided with the tire which makes a 2nd embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel 10 Wheel main body 20 Tire 21 Base part 25 1st tread part 26 2nd tread part

Claims (12)

In a rubber tire having an annular base portion and a large number of tread portions having the same height and projecting from the outer periphery of the base portion,
The multiple tread portions include at least two types of tread portions, a first tread portion and a second tread portion, and the second tread portion is disposed between the first tread portions separated in the circumferential direction,
The first tread portion has high bending rigidity and does not bend even when subjected to a tire circumferential force, and the second tread portion has a lower bending rigidity than the first tread portion and can be bent when subjected to the tire circumferential force. a tire characterized by some.   The tire according to claim 1, wherein a circumferential thickness of the second tread portion is thinner than that of the first tread portion.   The said 2nd tread part can be bend | folded in a tire circumferential direction until it becomes the height of 1/3-2/3 compared with the height in a non-bending state, The Claim 2 characterized by the above-mentioned. tire.   The first and second tread parts have a trapezoidal vertical cross-sectional shape along a plane perpendicular to the central axis of the tire, and the bottom of the second tread part is thinner than the bottom of the first tread part. The tire according to claim 2 or 3.   The tire according to any one of claims 2 to 4, wherein the second tread portion extends in the tire width direction and a planar shape thereof is bent.   The tire according to any one of claims 1 to 5, wherein a plurality of the second tread parts are arranged between the first tread parts.   All the 1st tread parts are arrange | positioned at equal intervals in the circumferential direction, The tire in any one of Claims 1-6 characterized by the above-mentioned.   The outer periphery of the base portion has two annular regions adjacent to each other in the width direction. In the two annular regions, the first and second tread portions are arranged in the same pattern and shifted in phase. The tire according to any one of claims 1 to 7, wherein a second tread portion is disposed in each annular region between the tread portion and the first tread portion of the other annular region.   Between the first tread portion of the one annular region and the first tread portion of the other annular region, a plurality of second tread portions are respectively disposed in the annular regions so as to be shifted in the circumferential direction. The tire according to claim 8.   10. The tire according to claim 8, wherein the second tread portion of the other annular region is arranged adjacent to the width direction of the first tread portion in the one annular region.   The tire according to any one of claims 1 to 10, wherein the base portion has a solid belt shape.   The tire according to claim 1, which is attached to a wheel driven by an electric motor.

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