JP3136167B2 - Agricultural wheel and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural wheel used for a rice transplanter, a management machine, a cultivator, a tractor, and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art This kind of agricultural wheel is disclosed in
No. 27130, a rubber-baked wheel, a hollow wheel as disclosed in Japanese Patent Application Laid-Open No. 2-241706, and a pneumatic tire as disclosed in Japanese Patent Publication No. 1-24084. There are wheels. The rubber-baked wheel has a ring-shaped rim covered with an elastic body such as rubber by baking and vulcanization, and a lug and a blade are integrally formed on the elastic body, and the inside of the elastic body is solid.

[0003] The hollow wheel is formed by splitting an elastic body integrally formed with a lug, a blade, and an internal cavity, and covering the annular elastic rim with the annular rim and joining each other to form a zero air pressure inside. (Atmospheric pressure). A pneumatic tire wheel is formed by forming an annular hollow elastic body having lugs and vanes, fitting this hollow elastic body to an annular rim, and applying an air pressure higher than the atmospheric pressure to the inside thereof.

[0004]

Since the rubber-baked wheel is solid inside, it is easy to manufacture, and the internal pressure control is unnecessary and the cost is low. However, the vibration is large and the rim is formed by a circular pipe. Then, since the contact area becomes small, the settlement becomes large, and if the rim is made wide, the cost becomes high. Hollow wheels have the advantages of being less hollow, requiring less internal pressure control, and having less vibration than rubber-baked wheels, because the elastic body width can be made wider by being hollow inside. However, the halved elastic body is to be bonded by face-to-face pressing after forming the lugs and blades in advance, and there is a joint at the center of the tread part, and if foreign matter enters the joint, it may peel off from it. Difficult to complete bonding. Further, since the hollow portion is sealed with zero internal pressure, the outer shape of the elastic body may be deformed due to a change in air temperature, particularly, a temperature drop, and the thickness of the sidewall portion needs to be increased. Further, when the hollow wheel is stored while being mounted on the machine, a flat spot-like deformation may occur in the ground contact portion, and vibration may be generated when the machine is next moved.

[0005] Pneumatic tire wheels have the least vibration compared to the former two wheels, can reduce the amount of sinking by widening the tire width, and can reduce the weight by reducing the thickness of the sidewall portion.
There is a problem that puncturing may occur, and the internal pressure naturally decreases during long-term storage, so that internal pressure management is required, and the production cost is relatively high. As described above, the three conventional techniques have various advantages but have many disadvantages, and it is difficult to combine all the advantages of low cost, small vibration, small settlement, small breakage, and easy manufacturing. Met.

[0006] By the way, in a wheel whose blades protrude greatly to the side from the wheel body, it is necessary to reduce the rigidity of the wheel body and increase the rigidity of the blades to increase the traction force while effectively absorbing vibration. It is known that slip can be reduced. The present invention provides an agricultural wheel that has all of the above advantages by enclosing a foam in an elastic body made of an elastic material such as rubber that covers a rim, and by forming lugs and blades with higher hardness than the body. And a method for producing the same.

[0007]

A specific means for solving the problems in the agricultural wheel of the present invention is to form a ring by covering an annular rim with an elastic material such as rubber, and to form a ring around the outer periphery of the ring. The lug and the vane are integrally formed at intervals in the direction, and the ring body includes a foam body over the entire circumference in an elastic body radially outside the rim, and this foam body is provided with an adhesive rubber layer on the rim. Contact through
Together they are combined and is to the lugs and blade formed by the hard rubber or the like elastic material than Watai (claim 1).
Further, in claim 1, the foam in the elastic body has an inner periphery.
The inner foam is composed of a side foam and an outer foam.
The hardness of the body is higher than the hardness of the outer peripheral foam.
(Claim 2). Further, in claim 1 or 2
Contact stomach, your tire maximum width portion of the elastic body in the wheel body
When the width of the tire is W and the width of the foam is Y,
= 0.6W to 0.9W.
3).

A specific means for solving the problem in the method for manufacturing an agricultural wheel of the present invention is to provide a foaming agent having a lower hardness than the rubber material and a low-temperature foaming in a deep portion of a rubber material having a circumferential groove opened inward. Is inserted, and an annular rim having an adhesive rubber layer on the outer periphery is inserted into the circumferential groove at a radial inside of the foamed rubber material, and the rubber material, the foamed rubber material and the rim are inserted into the upper and lower molds. The lugs and blades are equivalent to the outer diameter of the rubber material in the lower mold and have a hardness higher than that of the rubber material.
Place a slag consisting beam such as an elastic member, tightened while heating the upper and lower molds to a temperature above the foaming temperature of the foaming agent, in flowing slag, this by foaming foam rubber material
Foam rubber material to the annular rim via the adhesive rubber layer
At the same time, the rubber material and the slag are pressed against the upper and lower molds to be formed (claim 4) .

[0009] Further , according to claim 4, the foamed rubber material
Is a layer of the inner peripheral side foam rubber material and the outer peripheral side foam rubber material.
The hardness of the peripheral foam rubber material is higher than the hardness of the peripheral foam.
Hardness (claim 5).

[0010]

The foam body 9 contained in the elastic body 8 forming the ring body 6 is more easily elastically deformed than the elastic body 8, and when the elastic body 8 is deformed by external pressure, the foam body 9 has elasticity such that the external pressure is supported by air pressure. I support it. Since the inside of the elastic body 8 is filled with the foam body 9, deformation due to long-term storage and deformation due to temperature change are prevented, and the elastic body 8 can be formed to have a wide width, so that the contact area is large and the settlement is small.

The lug 12 and the blade 13 are formed by the elastic body 8 of the wheel body 6.
The lugs 12 and the blades 13 which are higher in hardness and have a high rigidity while retaining the vibration absorbing effect of the elastic body 8 generate a large traction force, and also exhibit braking performance. A foam rubber material 18 mixed with a foaming agent and a rim 5 are inserted into a circumferential groove 17 of a rubber material 16 forming the elastic body 8, and these are arranged in a lower mold 14, and a slag When the slag 22 is arranged and heated and formed in the upper and lower molds 14, the slag 22 heated most quickly flows from the mold 14, and the lugs 12 and the blades 13
Is formed, and at the same time, the molding of the elastic body 8 and the molding of the foam 9 are simultaneously performed.
Press 4 to form.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4, the agricultural wheel 1 has a central boss 2 and
A plurality of (three) spokes 3 provided radially from the boss 2 and a reinforcing plate 4 connecting the boss 2 and the spokes 3
And a ring 6 provided at the outer end of the spoke 3. The ring 6 is composed of a rim 5 welded to the outer end of the spoke 3, an elastic body 8 covering the rim 5, and the like. ing.

The rim 5 is formed of a pipe having a circular cross section together with the spokes 3 and has an annular shape concentric with the boss 2. An adhesive rubber layer 7 is provided on the entire outer periphery of the rim 5. Wheel 6
The elastic body 8 is fixed to the rim 5 to form an outer shape of a ring body, and includes a foam body 9 over the entire inner periphery thereof. The elastic body 8 has a JIS hardness of 50 to 70 degrees (J
(A-type hardness tester of IS). A lug 12 and a blade 13 protrude from a tread portion 11 of the elastic body 8. The lugs 12 and the blades 13 have a higher hardness than the elastic body 8, for example, a JIS hardness of 75 to 85 degrees (JIS A).
An elastic material such as rubber of a type hardness meter) is used.

The lugs protrude from the center of the tread portion 11 at equal intervals in the circumferential direction, and are provided with single-blade large blades 13L alternately from left to right from every three lugs 12; One wing-shaped small blade 13S protruding from the lug 12 alternately left and right is provided. These lug 12 and blade 1
3 is formed integrally with the elastic body 8, and there is no joint on the surface of the ring body 6 unlike a conventional hollow wheel. Elastic body 8
Has a substantially triangular shape, and covers the rim 5 and extends to the inner circumference, and has a range of approximately one-half to three-quarters around the circular cross section of the rim 5. Are bonded via an adhesive rubber layer 7. Sidewall portion 19 of elastic body 8
Is substantially equal to a conventional pneumatic tire wheel and is set to be thinner than a hollow wheel.

The foam 9 is obtained by kneading natural rubber or styrene-butadiene rubber or the like with a compounding compound such as carbon, a filler and sulfur, and further kneading a foaming agent, and using a rubber material containing a foaming agent. This is foamed by heating at the time of vulcanization, for example, a JIS hardness of 20 to 55 degrees, preferably a hardness of 25 to 45 degrees (by a JIS C-type hardness meter)
Is a relatively low-hardness sponge-like rubber body, and the volume change rate from the foaming agent-containing rubber material to the foam 9 is 150 to 400%. It can be adjusted by changing heating conditions and the like.

The foam 9 is enclosed in the elastic body 8 on the radial outside of the rim 5 and is joined to the rim 5 via the adhesive rubber layer 7, and has a deformable rectangular cross section wide in the left-right direction.
In order to secure a bonding area with the rim 5, the rim bonding surface on the inner peripheral side has an arc-shaped cross section. The manufacturing method of the agricultural wheel will be described based on FIG. 14D and 14U are a pair of upper and lower dies, each having annular cavities 15D and 15U divided into two in the wheel axis direction. Reference numeral 16 denotes an annular rubber material constituting the elastic body 8, which is formed in a U-shaped cross section having a circumferential groove 17 opened radially inward, and is disposed in the lower cavity 15D of the lower mold 14D.

Further, a lower cavity 15D of the lower mold 14D is provided.
The step portion 23 serving as the mating surface of the upper mold 14D is provided on the outer side of
The slag 22 is arranged at the bottom. This slag 22 is a lug 1
2 and the amount of rubber corresponding to the blade 13 is formed in a square rod shape,
It is rolled into a ring and placed in the lower mold 14D. A foam rubber material 18 constituting the foam 9 is inserted into the peripheral groove 17 of the rubber material 16, and a rim 5 covered with the adhesive rubber layer 7 is inserted radially inside the foam rubber material 18. .

The rim 5 is aligned with the lower mold 14D, and when the upper and lower molds 14D and 14U are tightened, pins (not shown) in the upper and lower cavities 15D and 15U move in the wheel axis direction. The position is set, the foamed rubber material 18 is adhered to the rim 5, and the rubber material 16 is fitted to the rim 5 and the foamed rubber material 18, so that the rubber material 16 is radially and axially moved with respect to the rim 5. Is set approximately. From the state of FIG.
When tightening while heating to 75 ° C, the slag 22
Is softened by receiving heat from the upper and lower molds 14, and starts to flow into the cavity 15 by the press pressure, and the rubber material 16 is heated while being deformed by the press pressure and the heat while overlapping with this, and the foamed rubber is heated. When the material 18 reaches, for example, 110 to 130 ° C. due to conduction heat from the rubber material 16, foaming starts.

When the foamed rubber material 18 starts foaming, the fluid slag 22 and the rubber material 16 receive expansion pressure due to foaming from the inside in addition to deformation from the outside by the mold 14, and the fluidized slag 22 moves up and down. Cavity 15D,
The rubber material 16 flows into and fills the 15U lug-corresponding portion and the large / small blade corresponding portion, and the rubber material 16 restricts the flow area in the upper and lower cavities 15 to fill the elastic-corresponding portion and also flows toward the inner peripheral side of the rim 5. . At this time, even if the fluidized slag 22 and the rubber material 16 are slightly mixed, there is no problem.

For example, when the volume ratio of the foamed rubber material 18 is set to 1 with respect to the volume ratio 2 of the foamed body 9, and when the foamed rubber material 18 is expanded to 200%, the volume change rate becomes 200.
% Until the pressure at the time of expansion becomes zero.
Is pressed against the mold 14. On the other hand, the foamed rubber material 18
Is expanded to about 201% or more and about 400%, the volume change rate is about 200%. However, even if the foam 9 has a predetermined shape, it has elasticity (when the elastic body 8 is cut,
The foam 9 protrudes. ), The rubber material 16 is pressed against the mold 14 with a high pressure when inflated, and when it is made into a product, the same elastic performance as when high-pressure air is sealed in the elastic body 8 is given.

FIG. 6 shows a first modification of the agricultural wheel 1 according to the present invention. The foam 9 is formed into an elliptical cross section and has two inner and outer layers in the radial direction of the wheel. Are formed on approximately two-thirds or half of the circular cross-section. The foam 9 has an outer peripheral side foam 9A having a JIS hardness of 20 to
A foamed rubber material of 35 degrees (based on JIS C type hardness meter) is used, and the inner peripheral side foam 9B has a JIS hardness of 40 to 55, for example.
A foamed rubber material of a degree (based on a JIS C-type hardness meter) is used. The manufacture of the wheel 1 can be performed in the same manner as in the above-described embodiment, except that the foamed rubber material 18 is formed in two layers.

By making the inner peripheral side foam 9B relatively hard, not only the adhesion to the rim 5 can be improved, but also the traction by the blades 13 can be ensured. By making the foam 9A a material having a relatively low hardness or high expansion, a vibration absorbing effect can be ensured. Therefore, the running performance can be improved as a whole, and the vibration transmitted to the rim 5 can be further reduced. . In addition, the layer division of the said foam 9 can also form three or more layers inside and outside two or more layers with different hardness. The thickness (gauge) of the elastic body 8 is the thinnest at the tire maximum width portion, and when the tire width is W and the foam 9 width is Y, Y is preferably in the range of 0.6 to 0.9 W, and 0.7 to 0.7 W. 0.8W is optimal. The foam 9
If the width Y is larger than 0.9 W, the thickness of the elastic body 8 becomes too thin and may be deformed by the pressure of the foam 9, and if the width Y of the foam 9 becomes smaller than 0.6 W, The thickness of the elastic body 8 is too large, the bending becomes small, and the vibration absorption is deteriorated.

FIGS. 7 and 8 show a second modification of the present invention, in which a wheel 6 of a wheel 1 has two blades 1 protruding on both axial sides.
3A are formed at regular intervals in the circumferential direction.
Three block-shaped lugs 12A are provided at regular intervals therebetween. The two blades 13A have a shorter radial dimension than the one blade 13 of the embodiment, and have a length halfway through the sidewall portion. The foam 9 in the elastic body 8 has an outer peripheral foam 9A and an inner peripheral foam 9B as in the first modified example. Wheel 6
Is rounded, so that the ratio of the width to the thickness of the internal foam 9 is set to be small. A diversion ridge 21 is formed at the center of the tread portion 11 of the wheel body 6.

Incidentally, the multilayer structure and the ratio of the foam 9 to the tire width of the first modified example, the lug and blade shape of the second modified example, and the like can be applied to the above-described embodiment. Further, the present invention is not limited to the above-described embodiment and modified examples, and can be variously modified. For example, the lug 1 of the elastic body 8
2. Shapes of large and small blades 13L, 13S, both blades 13A, etc.
The number and the like may be changed. The cross-sectional shape of the rubber material 16 is the same as that of the circumferential groove 1 for inserting the foam rubber material 18 and the rim 5.
If it has 7, the outer shape can be set variously, and the foamed rubber material 18 should expand in a substantially uniform manner over the entire area, and may have a cross-sectional shape similar to the shape of the completed foam 9.

Further, the ring body 6 is formed by welding a metal plate forming the blades 13 to the rim 5 and disposing an elastic body 8 and a foam body 9 between the respective blade plates, or by pivoting the outer periphery of the disk on the rim 5. It may be bent in the direction to form a flange.

[0026]

According to the agricultural wheel of the present invention described in detail above,
When the elastic body is deformed by an external pressure, the foam is encapsulated in the elastic body outside the rim over the entire circumference, and the lugs and the blades are formed of an elastic material such as rubber having a higher hardness than the ring body. Can elastically support the elastic body from the inside like air pressure, has the same vibration reduction effect as the air pressure of conventional pneumatic tire wheels, can reduce the settlement by widening, can reduce puncture and internal pressure naturally There is no need for internal pressure control, and a foam is required as compared to a hollow wheel, but the side wall portion of the elastic body can be made sufficiently thin, and the weight of the foam is small, so that an increase in weight can be prevented. In addition,
It is possible to exert a significant traction performance and braking performance, its
The foam is bonded to the rim via an adhesive rubber layer
Therefore, the foam is strengthened by the adhesive rubber layer,
Of the foam and the rim are reliably maintained
As a result, the outer shape of the ring body can be secured with high accuracy for a long period of time.

According to the production method of the present invention, a foaming agent-mixed foamed rubber material and a rim are inserted into the circumferential groove of the rubber material.
This is placed in a mold, and lugs and slag equivalent to blades are arranged on the outside of these diameters. Since the slag is pre-heated and the rubber material is pressed against the mold from the inside by the expansion of the foamed rubber material, the molding accuracy of the outer shape of the lug, the blade and the elastic body is improved.

[Brief description of the drawings]

1 is a cross-sectional view showing the agricultural wheel of the present invention and corresponding to a cross section taken along line AA of FIG. 3;

FIG. 2 is a sectional view corresponding to a section taken along line BB of FIG. 3;

FIG. 3 is a plan view of an agricultural wheel.

FIG. 4 is an overall front view of the agricultural wheel.

FIG. 5 is an explanatory cross-sectional view for explaining the agricultural wheel manufacturing method of the present invention.

FIG. 6 is a sectional view showing a first modified example of the agricultural wheel of the present invention.

7 shows a second modified example of the agricultural wheel of the present invention, and shows C in FIG.
It is sectional drawing corresponding to the -C line cross section.

FIG. 8 is an overall front view of an agricultural wheel according to a second modified example.

[Explanation of symbols]

 Reference Signs List 1 agricultural wheel 5 rim 6 wheel body 8 elastic body 9 foam 12 lug 13 blade 14 mold 16 rubber material 17 circumferential groove 18 foam rubber material

Claims (5)

(57) [Claims] [Claim 1] The annular rim to form a wheel unit is coated with an elastic material such as rubber, are integrally formed with lugs and blade at a circumferential interval on the outer periphery of the wheel body, said wheel body all around the elastic body radially outward than the rim enclosing the foam, this
With foam bonded to the rim via an adhesive rubber layer
The agricultural wheel , wherein the lug and the blade are formed of an elastic material such as rubber having a higher hardness than the wheel body. 2. The foam in the elastic body includes an inner peripheral foam.
It is composed of a layer with the outer peripheral side foam, and the hardness of the inner peripheral side foam is
That the hardness of the outer peripheral foam is high
The agricultural wheel according to claim 1, characterized in that: 3. The maximum tire width of an elastic body in the wheel body.
Assuming that the tire width is W and the foam width is Y,
And Y = 0.6W to 0.9W.
The agricultural wheel according to claim 1 or 2, wherein 4. A rubber material having a circumferential groove opened radially inward.
In the back of the circumferential groove, it is foamed with lower hardness and lower temperature than rubber material
Insert a foamed rubber material mixed with a foaming agent.
An annular rim with an adhesive rubber layer on the outer circumference in the circumferential groove
Insert the rubber material, foam rubber material and rim
Insert it into the mold, and lug it to the outside of the rubber material in the lower mold.
Elastic material such as rubber, which is equivalent to blades and has a higher hardness than rubber material
A slag consisting of
Tighten while heating to a temperature higher than the foaming temperature,
The foamed rubber material is foamed while flowing
Joining the material to the annular rim via the adhesive rubber layer
And press the rubber material and slag against the upper and lower molds to form
A method for manufacturing an agricultural wheel. 5. The foamed rubber material according to claim 1, wherein said foamed rubber material is formed of an inner peripheral side foamed rubber material.
It is a layer of peripheral foam rubber material, and the hardness of the inner peripheral foam rubber material is
That the hardness of the outer peripheral foam is high
The method for producing an agricultural wheel according to claim 4, wherein: