WO2011018953A1 - Eyelet fitted to a rotary head of a corded lawnmower - Google Patents

Eyelet fitted to a rotary head of a corded lawnmower Download PDF

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Publication number
WO2011018953A1
WO2011018953A1 PCT/JP2010/063000 JP2010063000W WO2011018953A1 WO 2011018953 A1 WO2011018953 A1 WO 2011018953A1 JP 2010063000 W JP2010063000 W JP 2010063000W WO 2011018953 A1 WO2011018953 A1 WO 2011018953A1
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WO
WIPO (PCT)
Prior art keywords
eyelet
cord
rotary head
inner frame
outer frame
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PCT/JP2010/063000
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French (fr)
Japanese (ja)
Inventor
寛一 立花
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Tachibana Kanichi
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Application filed by Tachibana Kanichi filed Critical Tachibana Kanichi
Publication of WO2011018953A1 publication Critical patent/WO2011018953A1/en

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    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01D—HARVESTING; MOWING
    • A01D34/00—Mowers; Mowing apparatus of harvesters
    • A01D34/01—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus
    • A01D34/412—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters
    • A01D34/416—Flexible line cutters
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01D—HARVESTING; MOWING
    • A01D34/00—Mowers; Mowing apparatus of harvesters
    • A01D34/01—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus
    • A01D34/412—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters
    • A01D34/63—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters having cutters rotating about a vertical axis
    • A01D34/81—Casings; Housings

Definitions

  • the present invention is used in a cord type mower that rotates a tough cord such as nylon at high speed and cuts grass using the cord as a blade body, and an exit portion for feeding out a cord wound around a bobbin in a rotary head to the outside It is related with the eyelet (eyelet) which comprises.
  • the cord-type mower has a rotating head that rotates at a high speed at the tip of a shaft rod that serves as a handle, and a cord serving as a blade is wound around a bobbin and stored inside the rotating head.
  • the cord wound around the bobbin is drawn out and used for the required length in consideration of the range of mowing.
  • the fed cord portion rotates according to the rotation of the rotary head, and the grass is cut by hitting the cord violently against the grass.
  • the cord-type mower is less prone to accidents due to breakage of the metal blade, detachment of the blade, or scattering of stones hit by the rotation of the blade. It has the feature that it is excellent in safety.
  • cords such as nylon are inferior in hardness and strength as compared with metal blades, it is necessary to always check for wear and use new cords. For this reason, for example, a long cord is prepared and the grass is cut using a portion of the cord as a cutting blade, and when the cord portion in use is worn, an unused portion of the cord can be pulled out and used as a new cutting blade Is used.
  • the cord as the blade body is wound around the bobbin in the rotary head described above, and the eyelet constituting the exit portion for feeding the cord out from the rotary head to the outside has a cord while the rotary head is rotating. Irregular force due to the reaction received when mowing the grass continues to be applied. Further, the cord and the eyelet always rub against each other while the rotary head rotates, and the eyelet is damaged by scratching.
  • this eyelet is easily damaged, so it is necessary to replace the eyelet every time it is damaged.
  • the rotary head attached to the tip of the handle of the cord type mower is an inexpensive product sold for several thousand yen, when this eyelet is damaged, it is discarded without replacing the eyelet. The fact is that it has been replaced with a new rotating head. If the life of the eyelet can be extended, the replacement frequency of the rotating head itself becomes low, and it is possible to reduce the waste of discarding the rotating head itself that has no functional damage except that the eyelet is broken.
  • the inventor of this application tried to integrally form the eyelet with a ceramic material, in particular alumina ceramics, instead of aluminum die casting.
  • the strength was lower than that of a conventional aluminum die-cast eyelet. That is, it has been found that the eyelet integrally composed of alumina ceramic has a lower durability than a conventional aluminum die-cast eyelet.
  • the inventor of the present invention has intensively researched and found that the eyelet is formed as an integral structure of different materials for the outer frame and the inner frame, and a through hole for passing the cord is provided in the inner frame, and the surface of the through hole is made smooth.
  • the idea was that we could provide eyelets with increased durability.
  • an eyelet that can reduce the risk of breakage can be provided by using a material having a higher shear strength than the conventional aluminum die casting for the outer frame of the eyelet.
  • An object of the present invention is to provide an eyelet that is less damaged than a product and has excellent durability.
  • the eyelet attached to the rotary head of the cord type mower has the following characteristics.
  • the eyelet according to the present invention comprises an outer frame having an outer peripheral shape for mounting on a rotary head, and an inner frame disposed inside the outer frame and having a through-hole through which a cord is passed.
  • the outer frame and the inner frame are formed of different materials, and both are integrally coupled. Further, the surface of the through hole is smoothed.
  • the outer frame is formed of a material having a shear strength equal to or higher than that of aluminum die casting, and the inner frame has a Vickers hardness higher than that of aluminum die casting, and the surface smoothing treatment is performed. It is good to form with the material which is possible.
  • the outer frame is formed from a thermoplastic resin and the inner frame is formed from a ceramic material.
  • the inner frame is formed of a ceramic material and a surface coating layer for smoothing the surface of the through hole is formed.
  • the outer frame is an acrylonitrile-butadiene-styrene copolymerized synthetic resin (hereinafter sometimes abbreviated as ABS resin). It is good to form with.
  • ABS resin acrylonitrile-butadiene-styrene copolymerized synthetic resin
  • the outer frame is formed of ABS resin
  • the inner frame is formed of a ceramic material
  • the surface coating layer for smoothing the surface of the through hole is formed. It is good to form.
  • the ceramic material constituting the inner frame of the eyelet of the preferred embodiment of the present invention described above is alumina ceramic, and the surface coating layer for smoothing the surface of the through hole is formed of PbO, SiO 2 and Al 2 O. It is preferable to use a fired layer of glaze containing 3 and containing SiO 2 and Al 2 O 3 in a weight ratio of 10: 1.
  • the outer frame and the inner frame are formed of different materials, a material having a shear strength equal to or higher than that of the aluminum die casting can be selected as the outer frame, and aluminum can be used as the inner frame.
  • a material having a Vickers hardness higher than that of die casting and capable of surface smoothing can be selected, and an eyelet having excellent durability and mass productivity can be realized as compared with a conventional eyelet.
  • the outer frame is formed of a thermoplastic resin
  • a ceramic material having a Vickers hardness higher than that of aluminum die casting can be selected for the inner frame, and the surface of the through hole provided in the inner frame can be smoothed. Therefore, by providing the surface coating layer, it is possible to reduce the friction between the through hole and the cord passing through the through hole.
  • the outer frame is formed of ABS resin and the inner frame is formed of a ceramic material
  • the ABS resin has a shear strength equal to or higher than that of aluminum die casting, so this eyelet is integrated with only aluminum die casting.
  • the breaking strength is increased as compared to the case of formation. Therefore, by forming the outer frame with ABS resin, it is possible to realize an eyelet that is more durable than an eyelet formed by aluminum die casting.
  • the outer frame is made of ABS resin
  • the ABS resin is lighter than the aluminum die casting, so that the weight of the eyelet is also reduced.
  • the amount of deviation of the center of gravity of the rotating head from the center of rotation is smaller than that of a rotating head equipped with a heavy eyelet. Vibration noise can be suppressed low.
  • Ceramic material is also a material with higher Vickers hardness than aluminum die casting, and in particular, alumina ceramics (Alumina Ceramics (Al 2 O 3 )), which is a kind of fine ceramics (Advanced ceramics), as the ceramic material constituting the inner frame
  • alumina ceramics Al 2 O 3
  • Advanced ceramics Advanced ceramics
  • the outer frame and the inner frame are made of different materials as in the gist of the present invention. I understand that there is.
  • FIG. 2 is a diagram for explaining a state in which a rotary head is mounted on the cord-type mower shown in FIG. It is a figure which shows the schematic shape of the eyelet of the conventional aluminum die-casting. It is a figure which shows the schematic shape of the eyelet of embodiment of this invention. It is a figure which shows the schematic shape of the eyelet of the Example of this invention.
  • FIGS. 1 to 4 are only schematically shown to such an extent that the present invention can be understood, and the present invention is not limited to the illustrated examples.
  • the same constituent elements are denoted by the same reference numerals, and redundant description of these functions may be omitted.
  • FIG. 1 is a diagram showing a schematic configuration of a cord type mower to which an eyelet according to an embodiment of the present invention is applied.
  • the cord type mower is configured by attaching a rotary head to a rotary head mounting chuck 18 provided with a shaft rod tip 16 at the tip of a shaft 14 serving as a handle.
  • FIG. 1 shows the shape of only the main body of a cord type mower without a rotating head. When the mowing operation is performed, the rotary head is attached to the rotary head mounting chuck 18.
  • a small engine 10 is attached to the other end opposite to the tip 16 side of the shaft rod 14 of the cord type mower, and the rotational force of the small engine 10 is transmitted through the shaft rod 14 to transmit power.
  • a mechanism (not shown) is transmitted to the rotary head, and the rotary head rotates.
  • a scattering prevention cover 20 is attached to the distal end portion 16 of the shaft rod 14 in order to prevent the grass that has been cut off or the broken pieces of the cord that have been worn away and scattered to a wide area around the peripheral portion.
  • FIG. 2 is a diagram for explaining how the rotary head 34 is attached to the cord type mower.
  • the rotary head 34 is attached to the rotary head mounting chuck 18 so as to rotate about the rotary head drive shaft 36.
  • a description of the power transmission mechanism and how the rotational force of the small engine 10 is transmitted to the rotary head by this power transmission mechanism is omitted.
  • a bobbin (not shown) for winding and storing the cord 32 is built in the rotary head 34, and the cord 32 can be drawn out from the bobbin only for the required length and used. It is configured.
  • An eyelet 30 is fitted to feed the cord 32 from the rotating head 34. In FIG. 2, the eyelet 30 is particularly hatched, but this does not mean that the cross section is shown.
  • the operator of the cord type mower holds the handle 12 and moves the tip 16 of the shaft rod so that the place where the grass to be mowed comes within the range where the cord 32 that rotates as the rotary head rotates rotates and scans. Let the mowing work.
  • FIG. 3 (A) to FIG. 3 (C) are diagrams showing a schematic shape of a conventional aluminum die-casting eyelet.
  • 3A is a front view
  • FIG. 3B is a side view
  • FIG. 3C is a rear view.
  • the conventional eyelet 30 is U-shaped as a whole, and is configured as an integral structure of aluminum die casting.
  • the outer portion 40 of the conventional eyelet 30 is processed into a shape that can be fixed by being fitted to the rotary head, but this shape belongs to the design matter of the rotary head and is classified by manufacturer or product.
  • the shape is different. Therefore, in FIG. 3 (A) to FIG. 3 (C), details of this shape are omitted and shown by a straight line. That is, the outer contour shape of the eyelet 30 is shown as a substantially rectangular shape.
  • the cord is fed out from the through hole 44 through a cord that functions as a cutting blade in the through hole 44 provided in the inner portion 42 of the eyelet 30.
  • the cut portion 46 of the eyelet 30 is provided for the purpose of firmly fixing to the rotary head.
  • FIGS. 4A to 4C are diagrams showing a schematic shape of an eyelet according to an embodiment of the present invention.
  • 4A is a front view
  • FIG. 4B is a side view
  • FIG. 4C is a rear view.
  • the overall shape of the eyelet 50 is a substantially U-shape as in the case of the conventional eyelet 30.
  • the eyelet 50 includes an outer frame 60 having an outer peripheral shape to be attached to the rotary head, and an inner frame 62 in which a through hole 64 that is disposed inside the outer frame 60 and passes a cord 32 (see FIG. 2) is formed. And has.
  • the outer frame 60 and the inner frame 62 are formed of different materials and are combined together, that is, directly or indirectly coupled.
  • the method of integrally combining the outer frame 60 and the inner frame 62 is realized by bonding and fixing (indirectly coupling) using an adhesive.
  • the outer frame 60 and the inner frame 62 can be firmly combined (directly coupled) without using an adhesive to combine them together.
  • the surface 64a of the inner frame 62 is smoothed.
  • This smoothing process is achieved by applying at least a portion of the material constituting the inner frame 62 that hits the surface of the through-hole 64 and performing mirror polishing, for example.
  • a surface coating layer is formed on the surface of the through hole 64.
  • the inner frame 62 is formed of a ceramic material such as alumina ceramic
  • a smoothing process is performed in which a glaze layer is formed by applying a glaze to the surface 64a and performing a sintering process. Is done.
  • the cut portion 66 of the eyelet 50 is provided for the purpose of firmly fixing to the rotary head.
  • FIGS. 5 (A) and (B) are diagrams showing a schematic shape of the eyelet 90 of the embodiment of the present invention.
  • FIG. 5 (A) is a front view
  • FIG. 5 (B) is a view showing a vertical sectional structure at a position indicated by QQ ′ in FIG. 5 (A).
  • the outer frame 100 is formed of an ABS resin that is a thermoplastic resin
  • the inner frame 102 is formed of alumina ceramics with a surface coating.
  • the surface 104a of the inner frame 102 is devised to reduce friction with the cord by applying a surface coating.
  • This surface coating treatment is realized by forming a surface coating layer 102b as a fired layer by applying glaze and firing.
  • the surface 104a of the inner frame 102 to which such a surface coating is applied has an effect of reducing friction with the cord by smoothing the fine irregularities on the plane.
  • the above-mentioned glaze contains PbO, SiO 2 and Al 2 O 3 and can be obtained by blending SiO 2 and Al 2 O 3 in a weight ratio of 10: 1.
  • the melting point of this glaze is determined by the content of PbO contained in this glaze. For example, when the firing temperature during the surface coating treatment, that is, the melting point of the glaze is 1000 ° C., the content (weight) of PbO with respect to the total weight of PbO, SiO 2 and Al 2 O 3 may be 64%. . Therefore, in this case, PbO, SiO 2 and Al 2 O 3 may be blended so that the weight ratio is 64: 32.7: 3.3.
  • the content ratio of PbO to the total weight of PbO, SiO 2 and Al 2 O 3 is determined according to how many times the firing temperature of the glaze is set, and all of PbO, SiO 2 and Al 2 O 3 are determined.
  • the remaining weight obtained by subtracting the weight of PbO from the weight may be distributed and prepared so as to be 10 to 1 with respect to SiO 2 and Al 2 O 3 .
  • the Vickers hardness given by the following formula (1) of aluminum die casting is 50 MPa (megapascal), whereas the Vickers hardness of alumina ceramics is 1700 MPa, which is 34 times higher.
  • (Vickers hardness) 0.102 ⁇ (F / S) (1)
  • F is a value obtained by measuring the magnitude of the force of the test load in units of N (Newton)
  • S is a load obtained from the shape of the dent left on the sample surface after removing the load. The value obtained by measuring the contact area with the sample surface in mm 2 units is shown.
  • the surface coating as described above is applied to reduce the frictional force between the surface 104a of the inner frame 102 and the cord 32, and the inner frame 102
  • the Vickers hardness of the alumina ceramics constituting is as high as 34 times the Vickers hardness of the conventional aluminum die casting.
  • the ABS resin constituting the outer frame 100 has a shear strength of 70 MPa, whereas the aluminum die cast has a shear strength of 60 MPa.
  • the eyelet 90 of the example With respect to the eyelet 90 of the example, a breaking experiment was performed in which the pressure value at the moment when the eyelet 90 broke was measured by applying pressure from both sides with the cut portion 106 as the center. As a result of the fracture experiment, the eyelet 90 of the example was 80 kg / cm 2 .
  • the damage caused during the operation of the mower which is the main cause of eyelet breakage, is due to the wear of the through-hole 104 due to friction with the above-mentioned cord and the hardness of the material reflected in the Vickers hardness Yes.
  • the eyelet of the embodiment formed by using alumina ceramics which is excellent in hardness evaluated by Vickers hardness as an inner frame, can reduce the frictional force between the inner surface of the through-hole 104 and the cord. 90 has much better damage resistance than conventional aluminum die-cast eyelets.
  • the eyelet 90 of the embodiment is excellent in durability.
  • the outer frame is made of ABS resin, thereby further increasing the breaking strength.
  • the weight of the eyelet made of aluminum die cast which is substantially the same size as the eyelet 90 of the example, was 5.5 g
  • the weight of the eyelet made of alumina ceramic was 5.7 g
  • the outer frame was made of aluminum die cast
  • the inner frame was made of alumina ceramics.
  • the weight of the eyelet was 5.6 kg.
  • the weight of the eyelet 90 of the example in which the outer frame 100 was made of ABS resin and the inner frame was made of alumina ceramics was 3.3 g.
  • Rotating heads with light eyelets are less displaced from the center of rotation of the center of gravity of rotating heads than rotating heads with heavy eyelets.
  • the magnitude of the centripetal force acting on the rotation center of the rotary head increases in proportion to the square of the distance from the rotation center of the rotary head to the position of the center of gravity. Further, the magnitude of the centripetal force acting on the rotation center of the rotary head is proportional to the sum of the weight of the eyelet and the weight of the rotary head. Accordingly, the smaller the weight of the eyelet, the smaller the centripetal force acting on the rotary head.
  • Vibration noise due to rotation of the rotating head decreases as the centripetal force acting on the rotation center of the rotating head decreases, so it is possible to reduce vibration noise due to rotation of the rotating head by reducing the weight of the eyelet. It becomes.
  • the rotary head equipped with the eyelet 90 of the embodiment can reduce the vibration noise accompanying the rotation of the rotary head.

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  • Life Sciences & Earth Sciences (AREA)
  • Environmental Sciences (AREA)
  • Harvester Elements (AREA)

Abstract

Disclosed is a damage-resistant and highly durable eyelet that forms a port through which a cord wrapped around a bobbin in a rotary head of a corded lawnmower is paid out. The disclosed eyelet is provided with: an outer rim (60) having an outside shape for attaching to the rotary head; and an inner rim (62) disposed inside the outer rim. A through-hole (64), through which the cord is run, is formed in the inner rim. The outer rim is formed from a thermoplastic resin, the inner rim is formed from a ceramic material, and the two are bonded together as a single unit. The surface (64a) of the through-hole is treated with a surface-smoothing treatment.

Description

コード式草刈機の回転ヘッドに取り付けられるアイレットEyelet attached to the rotary head of a corded mower
　この発明は、ナイロン等の強靭なコードを高速で回転させこのコードを刃体として草を刈るコード式草刈機に使用され、回転ヘッド内のボビンに巻かれたコードを外部に繰り出すための出口部分を構成するアイレット(eyelet)に関する。 The present invention is used in a cord type mower that rotates a tough cord such as nylon at high speed and cuts grass using the cord as a blade body, and an exit portion for feeding out a cord wound around a bobbin in a rotary head to the outside It is related with the eyelet (eyelet) which comprises.
　コード式草刈機は、柄の役割を果たす軸棒の先端に高速で回転する回転ヘッドを具えており、この回転ヘッドの内部には刃体となるコードがボビンに巻かれて収納されている。このボビンに巻かれたコードは、草刈を実施する範囲等を勘案して必要とされる長さ分だけ繰り出されて使用される。草刈作業が行われる際には、この繰り出されたコード部分が回転ヘッドの回転に従って回転し、コードが草に激しく打ち当たる事によって草が刈られる仕組みとなっている。 The cord-type mower has a rotating head that rotates at a high speed at the tip of a shaft rod that serves as a handle, and a cord serving as a blade is wound around a bobbin and stored inside the rotating head. The cord wound around the bobbin is drawn out and used for the required length in consideration of the range of mowing. When the mowing operation is performed, the fed cord portion rotates according to the rotation of the rotary head, and the grass is cut by hitting the cord violently against the grass.
　コード式草刈機は、従来の金属刃が取り付けられた方式の草刈機と異なり金属刃の割れや刃の外れ、刃の回転で当った石等の飛散による事故等が発生しにくく、作業時の安全性に優れているという特長を備えている。その一方で、ナイロン等のコードは金属刃と比べればその硬度並びに強度が劣るため、その磨耗等を見極めて、常に新しいコードを使用する必要がある。このため、例えば、長いコードを用意して、コードの一部分を刈刃として草を刈ることとし、この使用中のコード部分が磨耗したらコードの未使用の部分を引き出して新しい刈刃として使用できる構成が使われている。そして、回転ヘッド内にコードを巻きつけて収納するボビンを設け、このボビンからコードを必要とされる長さ分だけを繰り出して利用できるようにする等、様々な工夫が凝らされてきた（例えば、特許文献1～4を参照）。 Unlike conventional lawn mowers with a metal blade, the cord-type mower is less prone to accidents due to breakage of the metal blade, detachment of the blade, or scattering of stones hit by the rotation of the blade. It has the feature that it is excellent in safety. On the other hand, since cords such as nylon are inferior in hardness and strength as compared with metal blades, it is necessary to always check for wear and use new cords. For this reason, for example, a long cord is prepared and the grass is cut using a portion of the cord as a cutting blade, and when the cord portion in use is worn, an unused portion of the cord can be pulled out and used as a new cutting blade Is used. Various ideas have been devised, such as providing a bobbin for wrapping and storing the cord in the rotary head, and allowing the cord to be fed out from the bobbin only for the required length (for example, used). And see Patent Documents 1 to 4).
特開平７－３１２４９号公報Japanese Patent Laid-Open No. 7-31249 特開平９－２３８５３７号公報JP-A-9-238537 特開２００４－２４０１１号公報Japanese Patent Laid-Open No. 2004-24011 特開２００６－１４６８６号公報JP 2006-14686 A
　従来のアイレットは、量産性等に優れるアルミニウムダイカスト(die casting)によって全体が一体的に構成されているものが多い。 Many conventional eyelets are integrally formed of aluminum die casting that is excellent in mass productivity.
　刃体としてのコードは、上述の回転ヘッド内のボビンに巻かれており、このコードを回転ヘッドから外部へ繰り出すための出口部分を構成するアイレットには、回転ヘッドが回転している間コードが草を刈り取る際に受ける反作用等に起因する不規則な力が加わり続ける。また、コードとアイレットとは回転ヘッドが回転している間常に擦れ合い、アイレットには擦過による損傷が与えられる。 The cord as the blade body is wound around the bobbin in the rotary head described above, and the eyelet constituting the exit portion for feeding the cord out from the rotary head to the outside has a cord while the rotary head is rotating. Irregular force due to the reaction received when mowing the grass continues to be applied. Further, the cord and the eyelet always rub against each other while the rotary head rotates, and the eyelet is damaged by scratching.
　このため、このアイレットは破損しやすいので、破損する度にアイレットを交換する必要がある。しかしながら、コード式草刈機の柄の先端に取り付けられる回転ヘッドは数千円程度で販売される廉価な商品であるので、このアイレットが破損された場合には、アイレットを交換することなく廃棄され、新しい回転ヘッドに交換されているのが実情である。アイレットの寿命を延ばすことができれば、回転ヘッドそのものの交換頻度は低くなり、アイレットが破損している以外は何ら機能上の損傷のない回転ヘッドそのものを廃棄するという無駄を減らすことが可能である。 For this reason, this eyelet is easily damaged, so it is necessary to replace the eyelet every time it is damaged. However, since the rotary head attached to the tip of the handle of the cord type mower is an inexpensive product sold for several thousand yen, when this eyelet is damaged, it is discarded without replacing the eyelet. The fact is that it has been replaced with a new rotating head. If the life of the eyelet can be extended, the replacement frequency of the rotating head itself becomes low, and it is possible to reduce the waste of discarding the rotating head itself that has no functional damage except that the eyelet is broken.
　そこで、この出願に係る発明者は、アイレットをアルミニウムダイカストの代わりにセラミックス材料、特にアルミナセラミックスで一体的に構成することを試みたが、アイレットをアルミナセラミックスのみの単一材料で形成すると、その破断強度が従来のアルミニウムダイカスト製のアイレットよりも低いものとなった。すなわち、アルミナセラミックスで一体的に構成されたアイレットは、従来のアルミニウムダイカスト製のアイレットよりも耐久性が劣化することが分かった。 Therefore, the inventor of this application tried to integrally form the eyelet with a ceramic material, in particular alumina ceramics, instead of aluminum die casting. The strength was lower than that of a conventional aluminum die-cast eyelet. That is, it has been found that the eyelet integrally composed of alumina ceramic has a lower durability than a conventional aluminum die-cast eyelet.
　この発明の発明者は、鋭意研究したところ、アイレットを外枠と内枠の異なる材料の一体構造として形成し、内枠にコードを通す貫通孔を設けて、その貫通孔の表面を平滑面にしておけば、耐久性を高めたアイレットを提供できるということに想到した。更に、アイレットの外枠に、従来のアルミニウムダイカストと比較して、剪断強度の高い材料を使用すれば、破断の恐れを低減できるアイレットを提供できるということに想到した。 The inventor of the present invention has intensively researched and found that the eyelet is formed as an integral structure of different materials for the outer frame and the inner frame, and a through hole for passing the cord is provided in the inner frame, and the surface of the through hole is made smooth. The idea was that we could provide eyelets with increased durability. Furthermore, it has been conceived that an eyelet that can reduce the risk of breakage can be provided by using a material having a higher shear strength than the conventional aluminum die casting for the outer frame of the eyelet.
　この発明はこのような事情に着目してなされたものであり、コード式草刈機において、回転ヘッド内のボビンに巻かれたコードを外部へ繰り出すための出口部分を構成するアイレットであって、従来品よりも破損されにくく耐久性に優れるアイレットを提供することを目的とする。 The present invention has been made paying attention to such circumstances, in a cord type mower, an eyelet constituting an exit portion for feeding out a cord wound around a bobbin in a rotary head, An object of the present invention is to provide an eyelet that is less damaged than a product and has excellent durability.
　この発明の要旨によれば、コード式草刈機の回転ヘッドに取り付けられるアイレットは、以下の特徴を具えている。 According to the gist of the present invention, the eyelet attached to the rotary head of the cord type mower has the following characteristics.
　この発明のアイレットは、回転ヘッドに取り付けるための外周形状を有する外枠と、この外枠の内側に配置されてコードを通す貫通孔が形成された内枠とを具えている。そして、外枠及び内枠は相異なる材料で形成され、かつ両者が一体に結合されて構成される。更に、この貫通孔の表面は平滑化処理が施されている。 The eyelet according to the present invention comprises an outer frame having an outer peripheral shape for mounting on a rotary head, and an inner frame disposed inside the outer frame and having a through-hole through which a cord is passed. The outer frame and the inner frame are formed of different materials, and both are integrally coupled. Further, the surface of the through hole is smoothed.
　この発明の好適な実施形態のアイレットによれば、外枠を剪断強度がアルミニウムダイカストと同等かそれよりも高い材料で形成し、内枠をアルミニウムダイカストよりもビッカース硬度が高く表面の平滑化処理が可能である材料で形成するのが良い。 According to the eyelet of a preferred embodiment of the present invention, the outer frame is formed of a material having a shear strength equal to or higher than that of aluminum die casting, and the inner frame has a Vickers hardness higher than that of aluminum die casting, and the surface smoothing treatment is performed. It is good to form with the material which is possible.
　また、この発明の更に他の好適な実施形態のアイレットによれば、外枠を熱可塑性樹脂(Thermoplastic resin)で形成し、内枠をセラミックス材料で形成するのが良い。 According to the eyelet of still another preferred embodiment of the present invention, it is preferable that the outer frame is formed from a thermoplastic resin and the inner frame is formed from a ceramic material.
　また、この発明の更に他の好適な実施形態のアイレットによれば、内枠をセラミックス材料で形成し、かつ貫通孔の表面に対する平滑化処理のための表面コーティング層を形成するのが良い。 According to the eyelet of still another preferred embodiment of the present invention, it is preferable that the inner frame is formed of a ceramic material and a surface coating layer for smoothing the surface of the through hole is formed.
　また、この発明の他の好適な実施形態のアイレットによれば、外枠をアクリルニトリル・ブタジエン・スチレン(Acrylonitrile-Butadiene-Styrene)共重合合成樹脂（以後、ABS樹脂と略記することもある。）で形成するのが良い。 Further, according to the eyelet of another preferred embodiment of the present invention, the outer frame is an acrylonitrile-butadiene-styrene copolymerized synthetic resin (hereinafter sometimes abbreviated as ABS resin). It is good to form with.
　この発明の更に他の好適な実施形態のアイレットによれば、外枠をABS樹脂で形成し、内枠をセラミックス材料で形成し、かつ貫通孔の表面に対する平滑化処理のための表面コーティング層を形成するのが良い。 According to the eyelet of still another preferred embodiment of the present invention, the outer frame is formed of ABS resin, the inner frame is formed of a ceramic material, and the surface coating layer for smoothing the surface of the through hole is formed. It is good to form.
　更に、上述したこの発明の好適な実施形態のアイレットの内枠を構成するセラミックス材料をアルミナセラミックスとし、貫通孔の表面に対する平滑化処理のための表面コーティング層を、PbO、SiO2及びAl2O3を含みSiO2とAl2O3とが10対1の重量比で調合された釉薬の焼成層とするのが良い。 Further, the ceramic material constituting the inner frame of the eyelet of the preferred embodiment of the present invention described above is alumina ceramic, and the surface coating layer for smoothing the surface of the through hole is formed of PbO, SiO 2 and Al 2 O. It is preferable to use a fired layer of glaze containing 3 and containing SiO 2 and Al 2 O 3 in a weight ratio of 10: 1.
　この発明によれば、外枠と内枠とが相異なる材料で形成されるので、外枠として剪断強度がアルミニウムダイカストと同等かそれよりも高い材料を選定することができると共に、内枠としてアルミニウムダイカストよりもビッカース硬度が高く表面の平滑化処理が可能な材料を選択することができ、従来のアイレットと比較して、耐久性に優れかつ量産性に優れるアイレットを実現することが可能となる。 According to the present invention, since the outer frame and the inner frame are formed of different materials, a material having a shear strength equal to or higher than that of the aluminum die casting can be selected as the outer frame, and aluminum can be used as the inner frame. A material having a Vickers hardness higher than that of die casting and capable of surface smoothing can be selected, and an eyelet having excellent durability and mass productivity can be realized as compared with a conventional eyelet.
　例えば、外枠を熱可塑性樹脂で形成する場合には、内枠をビッカース硬度がアルミニウムダイカストより高いセラミックス材料を選択することができ、この内枠に設けられる貫通孔の表面に対して平滑化のために表面コーティング層を設けることによって、貫通孔とこの貫通孔を通るコードとの摩擦を小さくすることが可能である。 For example, when the outer frame is formed of a thermoplastic resin, a ceramic material having a Vickers hardness higher than that of aluminum die casting can be selected for the inner frame, and the surface of the through hole provided in the inner frame can be smoothed. Therefore, by providing the surface coating layer, it is possible to reduce the friction between the through hole and the cord passing through the through hole.
　また、外枠をABS樹脂で形成し、かつ内枠をセラミックス材料で形成する場合には、ABS樹脂がアルミニウムダイカストよりも剪断強度が等しいか高いので、このアイレットは、アルミニウムダイカストのみで一体的に形成した場合と比較して、破断強度が増すことを実験によって確かめている。従って、外枠をABS樹脂で形成することによって、アルミニウムダイカストで形成したアイレットよりも一層耐久性に優れたアイレットを実現することが可能である。 In addition, when the outer frame is formed of ABS resin and the inner frame is formed of a ceramic material, the ABS resin has a shear strength equal to or higher than that of aluminum die casting, so this eyelet is integrated with only aluminum die casting. Experiments have confirmed that the breaking strength is increased as compared to the case of formation. Therefore, by forming the outer frame with ABS resin, it is possible to realize an eyelet that is more durable than an eyelet formed by aluminum die casting.
　また、外枠をABS樹脂で形成すれば、ABS樹脂がアルミニウムダイカストよりも軽いので、構成されるアイレットの重量も軽くなる。重量の軽いアイレットが装着された回転ヘッドを構成すると、回転ヘッドの重心位置の回転中心からのずれ量が重量の重いアイレットが装着された回転ヘッドに比べて小さくなるので、回転ヘッドの回転に伴う振動騒音を低く抑えることが可能となる。 Also, if the outer frame is made of ABS resin, the ABS resin is lighter than the aluminum die casting, so that the weight of the eyelet is also reduced. When a rotating head equipped with a light eyelet is configured, the amount of deviation of the center of gravity of the rotating head from the center of rotation is smaller than that of a rotating head equipped with a heavy eyelet. Vibration noise can be suppressed low.
　セラミックス材料は、またアルミニウムダイカストよりもビッカース硬度の高い材料であり、特に、内枠を構成するセラミックス材料として、ファインセラミックス(Advanced ceramics)の一種であるアルミナセラミックス(Alumina Ceramics (Al2O3))を採用することによって、従来品よりも遥かに耐損傷性に優れるアイレットを実現することが可能である。 Ceramic material is also a material with higher Vickers hardness than aluminum die casting, and in particular, alumina ceramics (Alumina Ceramics (Al 2 O 3 )), which is a kind of fine ceramics (Advanced ceramics), as the ceramic material constituting the inner frame By adopting, it is possible to realize an eyelet that is far superior in damage resistance than conventional products.
　従って、上述したように従来品よりも遥かに耐損傷性に優れるアイレットを実現するためには、この発明の要旨のように、外枠と内枠とが相異なる材料で形成するのが好適であることが分かる。 Therefore, as described above, in order to realize an eyelet that is far superior in damage resistance than the conventional product, it is preferable that the outer frame and the inner frame are made of different materials as in the gist of the present invention. I understand that there is.
この発明の実施形態のアイレットが適用されるコード式草刈機の概略的構成を示す図である。It is a figure which shows schematic structure of the cord type mower to which the eyelet of embodiment of this invention is applied. 図1に示したコード式草刈機に回転ヘッドが装着されている様子の説明に供する図である。FIG. 2 is a diagram for explaining a state in which a rotary head is mounted on the cord-type mower shown in FIG. 従来のアルミニウムダイカストのアイレットの概略的形状を示す図である。It is a figure which shows the schematic shape of the eyelet of the conventional aluminum die-casting. この発明の実施形態のアイレットの概略的形状を示す図である。It is a figure which shows the schematic shape of the eyelet of embodiment of this invention. この発明の実施例のアイレットの概略的形状を示す図である。It is a figure which shows the schematic shape of the eyelet of the Example of this invention.
　以下、図1～図4を参照してコード式草刈機の回転ヘッドに取り付けられるこの発明の実施形態のアイレットについて説明する。図1～図4は、この発明が理解できる程度に概略的に示してあるに過ぎず、この発明を図示例に限定するものではない。また、各図において同じ構成要素については同一の番号を付して示し、これらの機能等に関してその重複する説明を省略することもある。 Hereinafter, an eyelet according to an embodiment of the present invention attached to a rotary head of a cord type mower will be described with reference to FIGS. 1 to 4 are only schematically shown to such an extent that the present invention can be understood, and the present invention is not limited to the illustrated examples. In each figure, the same constituent elements are denoted by the same reference numerals, and redundant description of these functions may be omitted.
　まず、図1及び図2を参照して、この発明のアイレットが使用されるコード式草刈機の概略的構成及びその機能について説明する。図1は、この発明の実施形態のアイレットが適用されるコード式草刈機の概略的構成を示す図である。 First, referring to FIG. 1 and FIG. 2, a schematic configuration and function of a cord type mower using the eyelet of the present invention will be described. FIG. 1 is a diagram showing a schematic configuration of a cord type mower to which an eyelet according to an embodiment of the present invention is applied.
　コード式草刈機は、柄の役割を果たす軸棒14の先端の軸棒先端部16が具える回転ヘッド取り付けチャック18に回転ヘッドが装着されて構成される。図1においては、回転ヘッドが装着されていないコード式草刈機の本体部分のみの形状を示している。草刈作業が行われる際にはこの回転ヘッド取り付けチャック18に回転ヘッドが装着される。 The cord type mower is configured by attaching a rotary head to a rotary head mounting chuck 18 provided with a shaft rod tip 16 at the tip of a shaft 14 serving as a handle. FIG. 1 shows the shape of only the main body of a cord type mower without a rotating head. When the mowing operation is performed, the rotary head is attached to the rotary head mounting chuck 18.
　一方、コード式草刈機の軸棒14の先端部16の側と反対側の他端には小型エンジン10が取り付けられており、この小型エンジン10の回転力を軸棒14の内部を通る動力伝達機構（図示を省略してある。）により回転ヘッドに伝達し、回転ヘッドが回転する構成とされている。 On the other hand, a small engine 10 is attached to the other end opposite to the tip 16 side of the shaft rod 14 of the cord type mower, and the rotational force of the small engine 10 is transmitted through the shaft rod 14 to transmit power. A mechanism (not shown) is transmitted to the rotary head, and the rotary head rotates.
　また、軸棒14の先端部16には、刈り取られた草あるいは磨耗して千切れ飛ぶコードの破片等が周辺部の広い範囲に飛び散ることを防ぐために飛散防止カバー20が取り付けられている。 Further, a scattering prevention cover 20 is attached to the distal end portion 16 of the shaft rod 14 in order to prevent the grass that has been cut off or the broken pieces of the cord that have been worn away and scattered to a wide area around the peripheral portion.
　次に、図2を参照して、回転ヘッドが装着されている状態について説明する。図2は、コード式草刈機に回転ヘッド34が装着されている様子の説明に供する図である。回転ヘッド34は、回転ヘッド取り付けチャック18に、回転ヘッド駆動軸36を中心として回転するように装着される。ここでは、この発明の特長部分を構成する構成要素ではないので、動力伝達機構及びこの動力伝達機構によってどのように小型エンジン10の回転力が回転ヘッドに伝達されるかについての説明は省略する。 Next, with reference to FIG. 2, the state where the rotary head is mounted will be described. FIG. 2 is a diagram for explaining how the rotary head 34 is attached to the cord type mower. The rotary head 34 is attached to the rotary head mounting chuck 18 so as to rotate about the rotary head drive shaft 36. Here, since it is not a component that constitutes a feature of the present invention, a description of the power transmission mechanism and how the rotational force of the small engine 10 is transmitted to the rotary head by this power transmission mechanism is omitted.
　回転ヘッド34内には、コード32を巻きつけて収納するボビン（図示を省略してある。）が内蔵されており、このボビンからコード32を必要とされる長さ分だけを繰り出して利用できる構成とされている。この回転ヘッド34からコード32を繰り出すためアイレット30が嵌め込まれている。図2では、特にアイレット30にハッチングを付して示してあるが、これは断面を示す意味ではない。 A bobbin (not shown) for winding and storing the cord 32 is built in the rotary head 34, and the cord 32 can be drawn out from the bobbin only for the required length and used. It is configured. An eyelet 30 is fitted to feed the cord 32 from the rotating head 34. In FIG. 2, the eyelet 30 is particularly hatched, but this does not mean that the cross section is shown.
　コード式草刈機の操作者は、ハンドル12をつかんで、回転ヘッドの回転に伴って回転するコード32が回転走査する範囲内に、刈り取る草のある場所が来るように軸棒先端部16を移動させて草刈作業を行う。 The operator of the cord type mower holds the handle 12 and moves the tip 16 of the shaft rod so that the place where the grass to be mowed comes within the range where the cord 32 that rotates as the rotary head rotates rotates and scans. Let the mowing work.
　この発明の実施形態のアイレットの構成の説明に先立ち、アイレットの基本的構成の理解に資するために、図3(A)～図3(C)を参照して従来のアルミニウムダイカストのアイレットの形状について説明する。図3(A)～図3(C)は、従来のアルミニウムダイカストのアイレットの概略的形状を示す図である。図3(A)は正面図、図3(B)は側面図、及び図3(C)は背面図である。 Prior to the description of the configuration of the eyelet according to the embodiment of the present invention, in order to contribute to an understanding of the basic configuration of the eyelet, the shape of the conventional aluminum die-casting eyelet will be described with reference to FIGS. explain. FIG. 3 (A) to FIG. 3 (C) are diagrams showing a schematic shape of a conventional aluminum die-casting eyelet. 3A is a front view, FIG. 3B is a side view, and FIG. 3C is a rear view.
　従来のアイレット30は、図3(A)～図3(C)に示すように、全体形状がコの字形状であって、アルミニウムダイカストの一体構造体として構成されている。従来のアイレット30の外側部分40は、回転ヘッドに嵌めこんで固定することが可能である形状に加工されているが、この形状は回転ヘッドの設計的事項に属し、製造メーカあるいは製品ごとにその形状は異なっている。そのため図3(A)～図3(C)においては、この形状の詳細は省略して直線で示してある。すなわち、アイレット30の外側の輪郭形状は略長方形として示してある。 As shown in FIGS. 3 (A) to 3 (C), the conventional eyelet 30 is U-shaped as a whole, and is configured as an integral structure of aluminum die casting. The outer portion 40 of the conventional eyelet 30 is processed into a shape that can be fixed by being fitted to the rotary head, but this shape belongs to the design matter of the rotary head and is classified by manufacturer or product. The shape is different. Therefore, in FIG. 3 (A) to FIG. 3 (C), details of this shape are omitted and shown by a straight line. That is, the outer contour shape of the eyelet 30 is shown as a substantially rectangular shape.
　アイレット30の内側部分42に設けられた貫通孔44に刈刃として機能するコードを通して、この貫通孔44からコードが繰り出される。また、アイレット30の切り込み部分46は、回転ヘッドに強固に固定するための便宜のために設けられている。 The cord is fed out from the through hole 44 through a cord that functions as a cutting blade in the through hole 44 provided in the inner portion 42 of the eyelet 30. In addition, the cut portion 46 of the eyelet 30 is provided for the purpose of firmly fixing to the rotary head.
　図4(A)～図4(C)を参照して、この発明の実施形態のアイレットの形状及びその構成材料について説明する。図4(A)～図4(C)は、この発明の実施形態のアイレットの概略的形状を示す図である。図4(A)は正面図、図4(B)は側面図、及び図4(C)は背面図である。 With reference to FIGS. 4A to 4C, the shape of the eyelet and the constituent materials thereof according to the embodiment of the present invention will be described. 4 (A) to 4 (C) are diagrams showing a schematic shape of an eyelet according to an embodiment of the present invention. 4A is a front view, FIG. 4B is a side view, and FIG. 4C is a rear view.
　この発明の実施形態のアイレット50は、図4(A)～図4(C)に示すように、全体形状は従来のアイレット30と同様に概略コの字状の形状となっている。このアイレット50は、回転ヘッドに取り付けるための外周形状を有する外枠60と、この外枠60の内側に配置されてコード32（図2を参照）を通す貫通孔64が形成された内枠62とを具えている。そして、外枠60及び内枠62は相異なる材料で形成されかつ両者が一体に組み合わせられ、すなわち直接又は間接的に結合されて構成されている。 As shown in FIGS. 4 (A) to 4 (C), the overall shape of the eyelet 50 according to the embodiment of the present invention is a substantially U-shape as in the case of the conventional eyelet 30. The eyelet 50 includes an outer frame 60 having an outer peripheral shape to be attached to the rotary head, and an inner frame 62 in which a through hole 64 that is disposed inside the outer frame 60 and passes a cord 32 (see FIG. 2) is formed. And has. The outer frame 60 and the inner frame 62 are formed of different materials and are combined together, that is, directly or indirectly coupled.
　外枠60と内枠62とを一体に組み合わせる方法は、接着剤を用いて接着固定（間接的に結合）することで実現される。あるいは、接着剤を用いずに、外枠60と内枠62とを強固に嵌合（直接的に結合）することによっても両者を一体に組み合わせることが可能である。 The method of integrally combining the outer frame 60 and the inner frame 62 is realized by bonding and fixing (indirectly coupling) using an adhesive. Alternatively, the outer frame 60 and the inner frame 62 can be firmly combined (directly coupled) without using an adhesive to combine them together.
　更に、内枠62の表面64aは平滑化処理が施されている。この平滑化処理は、内枠62を構成する材料の少なくとも貫通孔64の表面に当たる部分に施され、例えば、鏡面研磨することによって達成される。しかしながら、鏡面研磨を施すことは、生産性の点から困難であるので、貫通孔64の表面に表面コーティング層を形成する。例えば、後述するように、アルミナセラミックス等のセラミックス材料で内枠62を形成する場合は、この表面64aに釉薬を塗布して焼結処理をすることによって釉薬の焼成層を形成するという平滑化処理が行われる。 Furthermore, the surface 64a of the inner frame 62 is smoothed. This smoothing process is achieved by applying at least a portion of the material constituting the inner frame 62 that hits the surface of the through-hole 64 and performing mirror polishing, for example. However, since it is difficult to perform mirror polishing from the viewpoint of productivity, a surface coating layer is formed on the surface of the through hole 64. For example, as will be described later, when the inner frame 62 is formed of a ceramic material such as alumina ceramic, a smoothing process is performed in which a glaze layer is formed by applying a glaze to the surface 64a and performing a sintering process. Is done.
　また、従来例のアイレット30と同様に、アイレット50の切り込み部分66は、回転ヘッドに強固に固定するための便宜のために設けられている。 Further, similarly to the eyelet 30 of the conventional example, the cut portion 66 of the eyelet 50 is provided for the purpose of firmly fixing to the rotary head.
　＜実施例＞
　図5(A)及び(B)を参照して、この発明の実施例のアイレットの形状及びその構成材料について説明する。図5(A)及び(B)は、この発明の実施例のアイレット90の概略的形状を示す図である。図5(A)は正面図、図5(B)は図5(A)のQQ'で示す位置における垂直断面構造を示す図である。 <Example>
With reference to FIGS. 5 (A) and (B), the shape of the eyelet and its constituent materials according to the embodiment of the present invention will be described. 5 (A) and 5 (B) are diagrams showing a schematic shape of the eyelet 90 of the embodiment of the present invention. FIG. 5 (A) is a front view, and FIG. 5 (B) is a view showing a vertical sectional structure at a position indicated by QQ ′ in FIG. 5 (A).
　実施例のアイレット90は、外枠100を熱可塑性樹脂であるABS樹脂で形成し、かつ内枠102を表面コーティングが施されたアルミナセラミックスで形成されている。内枠102の表面104aは、表面コーティングを施すことによって、コードとの摩擦を小さくする工夫が施されている。 In the eyelet 90 of the example, the outer frame 100 is formed of an ABS resin that is a thermoplastic resin, and the inner frame 102 is formed of alumina ceramics with a surface coating. The surface 104a of the inner frame 102 is devised to reduce friction with the cord by applying a surface coating.
　この表面コーティング処理は、釉薬を塗布して焼成することによって焼成層としての表面コーティング層102bを形成することによって実現される。 This surface coating treatment is realized by forming a surface coating layer 102b as a fired layer by applying glaze and firing.
　このような表面コーティングが施された内枠102の表面104aは、平面の微小な凹凸が平滑化されることによって、コードとの摩擦が小さくなる効果を有する。 The surface 104a of the inner frame 102 to which such a surface coating is applied has an effect of reducing friction with the cord by smoothing the fine irregularities on the plane.
　上述の釉薬は、PbO、SiO2及びAl2O3を含み、SiO2とAl2O3とを10対1の重量比で調合することで得られる。この釉薬の融点は、この釉薬に含まれるPbOの含有量で決まる。例えば、表面コーティング処理の際の焼成温度、すなわち釉薬の融点を1000℃とする場合は、PbO、SiO2及びAl2O3の全重量に対するPbOの含有量(重量)を64%とすればよい。従って、この場合は、PbO、SiO2及びAl2O3を重量比で、64：32.7：3.3となるように調合すればよい。すなわち、釉薬の焼成温度を何度に設定するかに対応させてPbO、SiO2及びAl2O3の全重量に対するPbOの含有量比を決定し、PbO、SiO2及びAl2O3の全重量からPbOの重量を引き去った残りの重量をSiO2とAl2O3とに対して10対1となるように分配して調合すればよい。 The above-mentioned glaze contains PbO, SiO 2 and Al 2 O 3 and can be obtained by blending SiO 2 and Al 2 O 3 in a weight ratio of 10: 1. The melting point of this glaze is determined by the content of PbO contained in this glaze. For example, when the firing temperature during the surface coating treatment, that is, the melting point of the glaze is 1000 ° C., the content (weight) of PbO with respect to the total weight of PbO, SiO 2 and Al 2 O 3 may be 64%. . Therefore, in this case, PbO, SiO 2 and Al 2 O 3 may be blended so that the weight ratio is 64: 32.7: 3.3. That is, the content ratio of PbO to the total weight of PbO, SiO 2 and Al 2 O 3 is determined according to how many times the firing temperature of the glaze is set, and all of PbO, SiO 2 and Al 2 O 3 are determined. The remaining weight obtained by subtracting the weight of PbO from the weight may be distributed and prepared so as to be 10 to 1 with respect to SiO 2 and Al 2 O 3 .
　アルミニウムダイカストの、次式(1)で与えられるビッカース硬度が50 MPa(メガパスカル)であるのに対して、アルミナセラミックスのビッカース硬度は1700 MPaとその硬度は34倍である。
（ビッカース硬度）＝0.102×(F/S)　　　　　　(1)
　ここで、Fは試験荷重の力の大きさをN(ニュートン)単位で測定して得られた値であり、Sは荷重を除いた後に試料表面に残された凹みの形状から求められる荷重と試料表面との接触面積をmm2単位で測定して得られた値を示す。 The Vickers hardness given by the following formula (1) of aluminum die casting is 50 MPa (megapascal), whereas the Vickers hardness of alumina ceramics is 1700 MPa, which is 34 times higher.
(Vickers hardness) = 0.102 × (F / S) (1)
Here, F is a value obtained by measuring the magnitude of the force of the test load in units of N (Newton), and S is a load obtained from the shape of the dent left on the sample surface after removing the load. The value obtained by measuring the contact area with the sample surface in mm 2 units is shown.
　従って、実施例のアイレット90によれば、上述のような表面コーティングが施されることによって、内枠102の表面104aとコード32との摩擦力の低減が図られている上に、内枠102を構成するアルミナセラミックスのビッカース硬度は、従来のアルミニウムダイカストのビッカース硬度の34倍という高い値を有している。 Therefore, according to the eyelet 90 of the embodiment, the surface coating as described above is applied to reduce the frictional force between the surface 104a of the inner frame 102 and the cord 32, and the inner frame 102 The Vickers hardness of the alumina ceramics constituting is as high as 34 times the Vickers hardness of the conventional aluminum die casting.
　一方、外枠100を構成するABS樹脂の剪断強度の大きさは、70 MPaであるのに対して、アルミニウムダイカストの剪断強度の大きさはこれより小さく60 MPaである。 On the other hand, the ABS resin constituting the outer frame 100 has a shear strength of 70 MPa, whereas the aluminum die cast has a shear strength of 60 MPa.
　実施例のアイレット90に対して、切り込み部分106を中心に据えて両側から圧力をかけてアイレット90が破断する瞬間の圧力値を測定する破断実験を行った。この破断実験の結果、実施例のアイレット90では80 kg/cm2であった。 With respect to the eyelet 90 of the example, a breaking experiment was performed in which the pressure value at the moment when the eyelet 90 broke was measured by applying pressure from both sides with the cut portion 106 as the center. As a result of the fracture experiment, the eyelet 90 of the example was 80 kg / cm 2 .
　一般にアイレットの破損の主な原因となる、草刈機の動作中に受ける損傷は、上述のコードとの摩擦による貫通孔104部分の磨耗、及びビッカース硬度に反映される材料の硬さに起因している。これに対して草刈機の動作中にアイレットの両側から大きな圧力が加わる機会はあまりない。従って、貫通孔104の内側の面とコードとの摩擦力の低減が図られ、かつビッカース硬度で評価される硬さに格段に優れるアルミナセラミックスを内枠として利用されて形成された実施例のアイレット90は、従来のアルミニウムダイカスト製のアイレットに比べて格段に優れた耐損傷性を有している。 In general, the damage caused during the operation of the mower, which is the main cause of eyelet breakage, is due to the wear of the through-hole 104 due to friction with the above-mentioned cord and the hardness of the material reflected in the Vickers hardness Yes. On the other hand, there is not much opportunity to apply large pressure from both sides of the eyelet during operation of the mower. Accordingly, the eyelet of the embodiment formed by using alumina ceramics, which is excellent in hardness evaluated by Vickers hardness as an inner frame, can reduce the frictional force between the inner surface of the through-hole 104 and the cord. 90 has much better damage resistance than conventional aluminum die-cast eyelets.
　上述したように、コード式草刈機の動作中にアイレットの両側から大きな圧力が加わることはあまりないが、コード32（図2を参照）が草刈中に何らかの突起物等に挟まれる等の突発的な事故があって、アイレットの両側から大きな圧力が加わることが稀には有り得る。このような事態をも含めて勘案すれば、実施例のアイレット90は耐久性に優れているといえる。 As mentioned above, there is not much pressure applied from both sides of the eyelet during the operation of the cord type mower, but the cord 32 (see Fig. 2) is suddenly caught by some kind of projection during mowing. In rare cases, it is possible that a large accident will cause a large pressure from both sides of the eyelet. Considering such a situation, it can be said that the eyelet 90 of the embodiment is excellent in durability.
　すなわち、実施例のアイレット90によれば、内枠がアルミナセラミック製であることから耐損傷性に優れることに加えて、外枠をABS樹脂製としたことによって、破断強度が更に高められている。 That is, according to the eyelet 90 of the example, in addition to being excellent in damage resistance because the inner frame is made of alumina ceramic, the outer frame is made of ABS resin, thereby further increasing the breaking strength. .
　また、実施例のアイレット90と寸法のほぼ等しい、アルミニウムダイカスト製のアイレットの重量は5.5 g、アルミナセラミックス製のアイレットの重量は5.7 g、外枠がアルミニウムダイカストで内枠がアルミナセラミックスで構成されたアイレットの重量は5.6 gであった。それに対して、外枠100をABS樹脂とし内枠をアルミナセラミックスで形成した実施例のアイレット90の重量は3.3 gであった。 In addition, the weight of the eyelet made of aluminum die cast, which is substantially the same size as the eyelet 90 of the example, was 5.5 g, the weight of the eyelet made of alumina ceramic was 5.7 g, the outer frame was made of aluminum die cast, and the inner frame was made of alumina ceramics. The weight of the eyelet was 5.6 kg. On the other hand, the weight of the eyelet 90 of the example in which the outer frame 100 was made of ABS resin and the inner frame was made of alumina ceramics was 3.3 g.
　重量の軽いアイレットが装着された回転ヘッドは、重量の重いアイレットが装着された回転ヘッドに比べて、回転ヘッドの重心位置の回転中心からのずれ量が小さくなる。回転ヘッドの回転中心から重心位置までの距離の2乗に比例して回転ヘッドの回転中心に働く向心力の大きさが大きくなる。また、回転ヘッドの回転中心に働く向心力の大きさは、アイレットの重量と回転ヘッドの重量の和に比例する。従って、アイレットの重量が軽いほど回転ヘッドに働く向心力の大きさは小さくなる。 Rotating heads with light eyelets are less displaced from the center of rotation of the center of gravity of rotating heads than rotating heads with heavy eyelets. The magnitude of the centripetal force acting on the rotation center of the rotary head increases in proportion to the square of the distance from the rotation center of the rotary head to the position of the center of gravity. Further, the magnitude of the centripetal force acting on the rotation center of the rotary head is proportional to the sum of the weight of the eyelet and the weight of the rotary head. Accordingly, the smaller the weight of the eyelet, the smaller the centripetal force acting on the rotary head.
　回転ヘッドの回転に伴う振動騒音は、回転ヘッドの回転中心に働く向心力の大きさが小さいほど低くなるので、アイレットの重量を軽くすることによる回転ヘッドの回転に伴う振動騒音を低く抑えることが可能となる。 Vibration noise due to rotation of the rotating head decreases as the centripetal force acting on the rotation center of the rotating head decreases, so it is possible to reduce vibration noise due to rotation of the rotating head by reducing the weight of the eyelet. It becomes.
　すなわち、実施例のアイレット90を装着した回転ヘッドは、回転ヘッドの回転に伴う振動騒音を小さくすることが可能である。 That is, the rotary head equipped with the eyelet 90 of the embodiment can reduce the vibration noise accompanying the rotation of the rotary head.
10：小型エンジン
12：ハンドル
14：軸棒
16：軸棒先端部
18：回転ヘッド取り付けチャック
20：飛散防止カバー
30：アイレット
32：コード
34：回転ヘッド
36：回転ヘッド駆動軸
40：外側部分
42：内側部分
44、64、104：貫通孔
46、66、106：切り込み部分
50：この発明の実施形態のアイレット
90：実施例のアイレット
60、100：外枠
62、102：内枠
102b：表面コーティング層 10: Small engine
12: Handle
14: Shaft bar
16: Shaft bar tip
18: Rotary head mounting chuck
20: Splash prevention cover
30: Eyelet
32: Code
34: Rotating head
36: Rotary head drive shaft
40: Outer part
42: Inside part
44, 64, 104: Through hole
46, 66, 106: notch
50: Eyelet according to an embodiment of the present invention
90: Example eyelet
60, 100: Outer frame
62, 102: Inner frame
102b: Surface coating layer

Claims (5)

  1. 　コード式草刈機が具える回転ヘッド内に収納されたコードを外部へ繰り出すための出口部分を構成するアイレットであって、
    　前記回転ヘッドに取り付けるための外周形状を有する外枠と、該外枠の内側に配置されて前記コードを通す貫通孔が形成された内枠とを具え、
    　前記外枠及び前記内枠は、相異なる材料で形成されており、かつ前記外枠及び前記内枠は一体に結合されて構成されており、
    　前記外枠は剪断強度がアルミニウムダイカストと同等かそれよりも高い材料が選択され、前記内枠がアルミニウムダイカストよりもビッカース硬度が高く表面の平滑化処理が可能である材料が選択されている、
    ことを特徴とするアイレット。     An eyelet that constitutes an exit portion for feeding out a cord housed in a rotary head provided with a cord type mower,
    An outer frame having an outer peripheral shape to be attached to the rotary head, and an inner frame that is disposed inside the outer frame and has a through-hole through which the cord passes.
    The outer frame and the inner frame are formed of different materials, and the outer frame and the inner frame are integrally combined,
    For the outer frame, a material having a shear strength equal to or higher than that of aluminum die casting is selected, and for the inner frame, a material having a Vickers hardness higher than that of aluminum die casting and capable of smoothing the surface is selected.
    An eyelet characterized by that.
  2. 　前記外枠は熱可塑性樹脂で形成されており、前記内枠はセラミックス材料で形成されていることを特徴とする請求項1に記載のアイレット。 2. The eyelet according to claim 1, wherein the outer frame is formed of a thermoplastic resin, and the inner frame is formed of a ceramic material.
  3. 　前記熱可塑性樹脂は、アクリルニトリル・ブタジエン・スチレン共重合合成樹脂であることを特徴とする請求項1に記載のアイレット。 2. The eyelet according to claim 1, wherein the thermoplastic resin is an acrylonitrile / butadiene / styrene copolymer synthetic resin.
  4. 　前記内枠は、前記貫通孔の表面に平滑化処理のための表面コーティング層が設けられていることを特徴とする請求項1に記載のアイレット。 2. The eyelet according to claim 1, wherein the inner frame is provided with a surface coating layer for smoothing treatment on a surface of the through hole.
  5. 　前記セラミックス材料は、アルミナセラミックスであって、前記表面コーティング層が、PbO、SiO2及びAl2O3を含み前記SiO2と前記Al2O3とが10対1の重量比で調合された釉薬の焼成層であることを特徴とする請求項4に記載のアイレット。 The ceramic material is an alumina ceramic, and the surface coating layer includes PbO, SiO 2 and Al 2 O 3 , and the glaze in which the SiO 2 and the Al 2 O 3 are mixed at a weight ratio of 10: 1. 5. The eyelet according to claim 4, wherein the eyelet is a fired layer.
PCT/JP2010/063000 2009-08-12 2010-08-02 Eyelet fitted to a rotary head of a corded lawnmower WO2011018953A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014143981A (en) * 2013-01-30 2014-08-14 Diatop Kk Bush cutting head of cord type bush cutter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60100369U (en) * 1983-12-13 1985-07-09 大同特殊鋼株式会社 Guide for linear materials
JPH05184915A (en) * 1992-01-07 1993-07-27 Ebara Corp Discharge reaction apparatus
JPH0646640A (en) * 1992-05-22 1994-02-22 Andreas Stihl:Fa Cutting head for cutter with thread-like cutting body
JPH09227253A (en) * 1996-02-21 1997-09-02 Kyoto Pref Gov Production of glaze for ceramics

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60100369U (en) * 1983-12-13 1985-07-09 大同特殊鋼株式会社 Guide for linear materials
JPH05184915A (en) * 1992-01-07 1993-07-27 Ebara Corp Discharge reaction apparatus
JPH0646640A (en) * 1992-05-22 1994-02-22 Andreas Stihl:Fa Cutting head for cutter with thread-like cutting body
JPH09227253A (en) * 1996-02-21 1997-09-02 Kyoto Pref Gov Production of glaze for ceramics

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014143981A (en) * 2013-01-30 2014-08-14 Diatop Kk Bush cutting head of cord type bush cutter

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