JP2006321425A - Agricultural wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agricultural wheel 14 enhancing durability without increasing the production cost. <P>SOLUTION: The agricultural wheel 14 is provided with a hub 16; spokes 18 radially extending from the hub 16; a reinforcement patch 22 having an outer surface joined to an end of the spoke 18; a rim 20 joined to an inner surface of the reinforcement patch 22; and an elastic wheel body 24 bonded to the rim 20. An inner surface of the reinforcement patch 22 is constituted such that it is surface-contacted with an outer surface of the rim 20. The elastic wheel body 24 comprises a vulcanized rubber. In the wheel 14, the reinforcement patches 22 are arranged at all positions where the spoke 18 and the rim 20 can be connected. Therefore, in the wheel 14, metal fatigue at the position where the rim 20 and the spoke 18 can be connected is suppressed. Such a wheel 14 has good durability. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to agricultural wheels.

  Agricultural machines such as management machines and rice transplanters use agricultural wheels in which rubber is baked on a metal rim. This wheel comprises a number of radially extending lugs. The wheel rim and the spoke are connected by welding.

  FIG. 4 is a partially cutaway side view showing a part of a conventional agricultural wheel 2. In FIG. 4, the spoke 4, the rim 6, the elastic ring body 8, and the plate 10 are shown. The spoke 4 and the rim 6 are directly connected by welding. A stress is concentrated on the connecting portion 12 formed by connecting the spoke 4 and the rim 6 during traveling. In the wheel 2, the plate 10 is applied to the connecting portion 12. The plate 10 reinforces the connecting portion 12. Since the connecting portion 12 is reinforced by the plate 10, the wheel 2 can be prevented from being damaged by stress concentration.

  In the rear-mounted passenger car planter, if the planter is lifted during turning, the load on the front wheel increases, so the front wheel may be immersed in mud. If the front wheels are immersed in the mud, the rice transplanter will be unable to run.

Japanese Patent No. 3183593 discloses a paddy wheel in which immersion into mud is suppressed. This wheel is configured such that an elastic ring body covered with a rim bulges outward in the axial direction.
Japanese Patent No. 3183593

  In agricultural wheels, stress concentrates on the connecting portion during traveling. When stress is concentrated on this connecting portion, the connecting portion causes metal fatigue, and damage such as the rim being torn to the spoke side occurs. Such a wheel is inferior in durability. In order to improve the durability of the wheel, it is necessary to prevent damage at the connecting portion.

  As shown in FIG. 4, in the agricultural wheel 2 in which the connecting portion 12 is reinforced by applying the plate 10 to the connecting portion 12, damage to the connecting portion 12 can be prevented. The presence of the plate 10 is considered in the mold for producing the wheel 2. In a mold in which the presence of the plate 10 is not considered, such a wheel cannot be produced because the plate 10 contacts the mold. Therefore, the mold used for production must be prepared according to the presence or absence of the plate 10. In this case, since the versatility of the mold is lowered, the production cost of the wheel 2 is increased.

  When the number of spokes provided on the wheel is increased, the stress applied to the connecting portion is relieved, so that damage at the connecting portion can be prevented. In order for such wheels to be produced, a mold that takes into account the number of spokes must be prepared. Even in this case, since the versatility of the mold is lowered, the production cost of the wheels is increased.

  In a wheel having a rim formed of a metal pipe with an increased plate thickness, the strength of the rim increases, so that the connecting portion can be prevented from being damaged without increasing the number of spokes. In this case, conventional molds can be used for the production of the wheels. On the other hand, since the mass of this wheel increases, the operability of the agricultural machine to which this wheel is attached is deteriorated. As material costs also increase, production costs increase.

  An object of the present invention is to provide agricultural wheels with improved durability without increasing production costs.

  An agricultural wheel according to the present invention includes a hub, spokes extending radially from the hub, a reinforcing patch joined to the end of the spoke and the outer surface thereof, a rim joined to the inner surface of the reinforcing patch, and the rim. And an elastic ring body to be baked. The inner surface of the reinforcing patch is configured to be in surface contact with the outer surface of the rim. This elastic ring body is made of a crosslinked rubber.

  Preferably, in the agricultural wheel, the reinforcing patch is disposed at all locations where the spoke and the rim can be connected.

  Preferably, in the agricultural wheel, the cross-sectional shape of the reinforcing patch is configured such that the inner surface of the reinforcing patch wraps the entire outer surface of the rim.

  In this agricultural wheel, the spoke and the rim are connected via a reinforcing patch. Accordingly, the thickness of the portion where the spoke can be joined is increased as compared with the conventional wheel in which the spoke is directly joined to the rim. And since the inner surface of this reinforcing patch is in surface contact with the outer surface of the rim, the stress applied to the rim during traveling is reduced compared to conventional wheels. For this reason, the metal fatigue in the location where a spoke and a rim can be connected can be suppressed. Even if such a wheel is used for a long period of time, it will not break as if the rim was torn to the spoke side. This wheel is excellent in durability. In addition to this, the wheel can be produced with an existing mold, so that the production cost does not increase.

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

  FIG. 1 is a partially cutaway side view showing an agricultural wheel 14 according to an embodiment of the present invention. In FIG. 1, the direction perpendicular to the paper surface is the axial direction of the wheel 14. An arrow line A represents the rotation direction of the wheel 14 during forward movement. FIG. 2 is an enlarged cross-sectional view along the line II-II of the wheel 14 of FIG. In FIG. 2, the vertical direction is the radial direction of the wheel 14, and the horizontal direction is the axial direction of the wheel 14. The wheel 14 includes a hub 16, a spoke 18, a rim 20, a reinforcing patch 22, and an elastic ring body 24. An iron wheel 26 is formed from the hub 16, the spoke 18, the rim 20, and the reinforcing patch 22.

  The hub 16 is disposed at the center of the wheel 14. An axle is fitted to the hub 16.

  The spokes 18 extend radially outward from the hub 16. The wheel 14 includes three spokes 18. Four or more spokes 18 may be used for the wheel 14. From the viewpoint of reducing the weight of the wheel 14, the spoke 18 is made of a metal pipe. Examples of the material of the spoke 18 include steel and stainless steel. Stainless steel is preferred from the viewpoint of corrosion resistance. The spoke 18 and the hub 16 are connected by welding. The spoke 18 and the hub 16 may be connected by a method such as riveting or bolting.

  The rim 20 is processed into an annular shape. From the viewpoint of reducing the weight of the wheel 14, the rim 20 is made of a metal pipe. The rim 20 is connected to the end 28 of the spoke 18 via a reinforcing patch 22. Examples of the material of the rim 20 include steel and stainless steel. Stainless steel is preferred from the viewpoint of corrosion resistance. In this specification, a portion where the rim 20 and the spoke 18 can be connected is the connecting portion 30.

  The reinforcing patch 22 is disposed on all the connecting portions 30 of the wheel 14. The outer surface 32 of the reinforcing patch 22 is joined to the end 28 of the spoke 18. The reinforcing patch 22 and the spoke 18 are welded at the end 28 of the spoke 18. The inner surface 34 of the reinforcing patch 22 is joined to the outer surface 36 of the rim 20. The reinforcing patch 22 and the rim 20 are welded at the end 38 of the reinforcing patch 22. Therefore, in this agricultural wheel 14, welds 40 and 42 are formed at the end 28 of the spoke 18 and the end 38 of the reinforcing patch 22. The cross-sectional shape of the reinforcing patch 22 is a substantially semicircular arc shape.

  Examples of the material of the reinforcing patch 22 include steel and stainless steel. Stainless steel is preferred from the viewpoint of corrosion resistance.

  The elastic ring body 24 is disposed outside the wheel 14 in the radial direction. The elastic ring body 24 is made of a crosslinked rubber. The elastic ring body 24 is baked on the rim 20. The elastic ring body 24 includes a lug 44 that protrudes outward in the radial direction. The lug 44 includes a straight guide 46, a propulsion unit 48, and an inclined surface 50. The straight guide 46 is disposed on the equator of the wheel 14. The propulsion unit 48 extends outward in the axial direction from the straight guide 46. The propulsion units 48 are alternately arranged on the left and right sides in the rotational direction on both sides of the linear guide unit 46. The inclined surface 50 is located between the two propulsion parts 48 arranged in the rotation direction. The inclined surface 50 is a side surface of the rectilinear guide 46. A propulsion unit 48 is disposed on the opposite side of the inclined surface 50 in the axial direction.

  The straight guide 46 includes a protrusion 52. The protrusions 52 are arranged in the rotation direction. Since the straight guiding part 46 is provided with the protrusion 52, the wheel 14 is excellent in traction performance.

  The propulsion unit 48 includes a kick surface 54 on the rotation direction side and a back surface 56 on the opposite side of the rotation direction. The agricultural machine is propelled by the kick surface 54 shearing the mud.

  The agricultural wheel 14 has a function of supporting the load of the agricultural machine. And this wheel 14 has the function to transmit the driving force and the braking force to the road surface, and to maintain the directionality of the agricultural machine, while reducing the impact during traveling. In order for the wheel 14 to maintain these functions, the form as the wheel 14 must be maintained.

  As described above, in the agricultural wheel 14, the reinforcing patch 22 having a substantially semicircular cross section is disposed between the spoke 18 and the rim 20. Therefore, the thickness of the portion to which the spoke 18 can be connected is thicker than that of the conventional wheel in which the spoke 18 is directly connected to the rim 20. For this reason, compared with the conventional wheel, the strength at the connecting portion 30 is increased. The reinforcing patch 22 is in surface contact with the rim 20. For this reason, compared with the conventional wheel, the stress applied to the rim 20 during traveling is reduced. As a result, in this wheel 14, metal fatigue in the connecting portion 30 can be suppressed. Even if such a wheel 14 is used for a long period of time, the rim 20 will not be damaged as it is torn to the spoke 18 side. In the wheel 14, the connecting portion 30 is efficiently reinforced by the reinforcing patch 22. Therefore, this wheel 14 can maintain the form as the wheel 14 without being damaged over a long period of time. This wheel 14 is excellent in durability. In addition to this, the steel wheel 26 of the wheel 14 can be put into an existing mold in which the elastic ring body 24 is formed in the same manner as a conventional steel wheel in which the connecting portion 30 is not reinforced. Since an existing mold can be used for the production of the wheel 14, the production cost of the wheel 14 does not increase.

  The manufacturing method of this agricultural wheel 14 is as follows. First, the hub 16, the spoke 18, the rim 20, and the reinforcing patch 22 are integrated by welding, and the iron wheel 26 is manufactured. Next, in order to remove oil, dirt, etc. adhering to the iron wheel 26, the iron wheel 26 is shot blasted. Then, after an adhesive is applied to the rim 20 or the like covered with the elastic ring body 24, a baking process is performed. On the other hand, the rubber composition in which the elastic ring body 24 is formed is manufactured by a kneader such as a Banbury mixer. This rubber composition is processed into a preform with the shape of the wheel 14 taken into account. Thereafter, the iron wheel 26 coated with the adhesive and the preform are put into a vulcanizer, and pressurized and heated. By this pressurization and heating, the rubber composition of the preformed body flows. By heating, the rubber composition of the preform is subjected to a crosslinking reaction. The rubber composition of the preform is completely crosslinked, and the elastic ring body 24 is molded. Simultaneously with the crosslinking reaction, the rubber composition, the adhesive, and the iron wheel 26 as the adherend cause an adhesion reaction. The elastic ring body 24 is baked on the iron wheel 26 by this adhesion reaction. In this way, the wheel 14 shown in FIG. 1 is obtained.

  Examples of the material of the crosslinked rubber constituting the elastic ring body 24 include natural rubber, styrene-butadiene rubber, butadiene rubber, and isoprene rubber. From the viewpoint of versatility, natural rubber is preferable.

  In the wheel 14 used as the front wheel of the agricultural machine, the hardness of the crosslinked rubber is preferably 53 or more and 75 or less. By setting the hardness to 75 or less, generation of vibration is suppressed. In this respect, the hardness is more preferably equal to or less than 70, and particularly preferably equal to or less than 65.

  In the wheel 14 used as the rear wheel of the agricultural machine, the hardness of the crosslinked rubber is preferably 60 or more and 85 or less. In particular, in a light weight class agricultural machine, the hardness is more preferably 60 or more and 65 or less from the viewpoint that generation of vibration is suppressed. In the weight class agricultural machine, the hardness is more preferably 75 or more and 85 or less from the viewpoint that the propulsive force of the machine body is improved.

  In the present invention, the hardness is measured by a type A durometer. A test specimen for measurement is cut out from the wheel 14. Three sheet-like test pieces having a thickness of 1.0 mm are stacked and measured.

  Examples of the adhesive used for baking the elastic ring body 24 and the iron wheel 26 include a chlorinated rubber adhesive, a phenol resin adhesive, and an isocyanate adhesive. From the viewpoint of versatility, a chlorinated rubber adhesive and a phenol resin adhesive are preferable.

  FIG. 3 is an enlarged cross-sectional view showing a part of an agricultural wheel 58 according to another embodiment. In FIG. 3, a spoke 60, a rim 62, a reinforcing patch 64, and an elastic ring body 66 are shown. In the wheel 58, the cross-sectional shape of the reinforcing patch 64 is a pipe shape in which the inner surface 68 of the reinforcing patch 64 wraps the entire outer surface 70 of the rim 62. The outer surface 72 of the reinforcing patch 64 is joined to the end 74 of the spoke 60. The reinforcing patch 64 and the spoke 60 are welded at the end 74 of the spoke 60. The inner surface 68 of the reinforcing patch 64 is joined to the outer surface 70 of the rim 62. Although not shown, the reinforcing patch 64 and the rim 62 are welded at the end of the reinforcing patch 64. The wheel 58 includes such a reinforcing patch 64 in all the connecting portions 76 of the wheel 58.

  The thickness of the portion of the wheel 58 to which the spoke 60 can be connected is thicker than the conventional wheel in which the spoke 60 is directly connected to the rim 62. For this reason, compared with the conventional wheel, the strength at the connecting portion 76 is increased. Since the reinforcing patch 64 is in surface contact with the rim 62, the stress applied to the rim 62 during traveling is reduced as compared with a conventional wheel. As a result, metal fatigue at the connecting portion 76 of the wheel 58 can be suppressed. Even if such a wheel 58 is used for a long period of time, the rim 62 will not be damaged as if it was torn to the spoke 60 side. Therefore, this wheel 58 can maintain the form as the wheel 58 without being damaged over a long period of time. This wheel 58 is excellent in durability. In addition to this, the steel wheel of the agricultural wheel 58 can be put into an existing mold in which the elastic ring body 66 is formed in the same manner as a conventional steel wheel in which the connecting portion 76 is not reinforced. Since an existing mold can be used for the production of the wheel 58, the production cost of the wheel 58 does not increase.

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

[Example 1]
Agricultural wheels of Example 1 having the basic configuration shown in FIGS. 1 and 2 and having the specifications shown in Table 1 below were obtained. In this agricultural wheel, all connecting portions to which the rim and the spoke can be connected are reinforced with the reinforcing patch. The size of the wheel is 650 (outer diameter) × 80 (width). For the rim and spoke, a metal pipe made of stainless steel having an outer diameter of 34 mm and a wall thickness of 3.2 mm was used. The thickness of the reinforcing patch is 3.2 mm. The material of the reinforcing patch is also stainless steel.

[Comparative Examples 1 and 2]
A wheel was obtained in the same manner as in Example 1 except that the method of reinforcing the connecting portion was changed. Comparative Example 1 is a conventional wheel in which the connecting portion is not reinforced. Comparative Example 2 is a wheel in which the connecting portion is reinforced with a plate as shown in FIG.

[Durability evaluation]
The prototype wheel was mounted on a drum durability tester. A load of 5880 N was applied to the contact surface between the wheel and the drum, and the drum was rotated at a speed of 10 km / h. And the time until the prototype wheel was damaged was measured. The relative evaluation which made the break time of the conventional wheel shown by the comparative example 1 100 was implemented. It shows that it is excellent in durability, so that this figure is large. The results are shown in Table 1. The slip angle in this testing machine is +/− 5 °.

  As shown in Table 1, it was confirmed that the agricultural wheels of the examples had improved durability. From this evaluation result, the superiority of the present invention is clear.

  The agricultural wheel according to the present invention can be mounted on various agricultural machines.

FIG. 1 is a partially cutaway side view showing an agricultural wheel according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view along the line II-II of the wheel of FIG. FIG. 3 is an enlarged cross-sectional view showing a part of an agricultural wheel according to another embodiment. FIG. 4 is a partially cutaway side view showing a part of a conventional agricultural wheel.

Explanation of symbols

2, 14, 58 ... Wheels 4, 18, 60 ... Spokes 6, 20, 62 ... Rims 8, 24, 66 ... Elastic rings 10 ... Plates 12, 30, 76 ... -Connection part 16 ... Hub 22, 64 ... Reinforcement patch 26 ... Iron wheel 28, 38, 74 ... End 32, 36, 70, 72 ... Outer surface 34, 68 ... Inner surface 40 42 ... Welding part 44 ... Lug 46 ... Linear guiding part 48 ... Propulsion part 50 ... Inclined surface 52 ... Protrusion 54 ... Kick surface 56 ... Back

Claims (3)

A hub, spokes extending radially from the hub, a reinforcing patch joined to the end of the spoke and the outer surface thereof, a rim joined to the inner surface of the reinforcing patch, and an elastic ring body baked on the rim. And
The inner surface of this reinforcing patch is configured to be in surface contact with the outer surface of the rim,
Agricultural wheels in which this elastic ring is made of crosslinked rubber.   The agricultural wheel according to claim 1, wherein the reinforcing patch is disposed at all locations where the spoke and the rim can be connected. The agricultural wheel according to claim 1 or 2, wherein the cross-sectional shape of the reinforcing patch is configured such that the inner surface of the reinforcing patch wraps the entire outer surface of the rim.

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