JP6415112B2 - Cutter rotating plate for brush cutter - Google Patents

Description

  The present invention relates to a rotating plate of a cutter that is rotationally driven in a brush cutter, and has a circular outer peripheral portion, and a plurality of blade portions are fixed to the outer peripheral portion.

  Conventionally, what is described in patent document 1 is known as a cutter used for a brush cutter. This cutter has a disk-shaped base metal and a plurality of blade parts respectively fixed to a plurality of positions along the peripheral edge of the base metal. Specifically, a plurality of notches arranged intermittently in the circumferential direction are formed in the peripheral portion of the base metal, and a portion of the base metal that sandwiches each notch from both sides in the circumferential direction is a portion on the rear side in the rotational direction. The blade portions are fixed to each other. The base metal is made of tool steel, while each blade portion is made of cemented carbide and is brazed to various parts of the base metal.

JP 2012-125181 A

In the cutter for the brush cutter, the rotary plate must be heated to a high temperature (for example, 700 ° C.) when the blades are brazed to the base metal constituting the rotary plate as the main body. In addition, with this heating, the rotating plate may be annealed and its strength may be reduced. Specifically, when the base material of the base metal, which is a rotating plate, is made of, for example, SK5, the base material is given high hardness (for example, Rockwell hardness HR _C = 60) by appropriate heat treatment (quenching). However, the base material is softened by being heated to 700 ° C. when the blade portion is brazed. And the larger the heated area, the more the base material loses its original high strength.

  In view of such circumstances, the present invention is a rotary plate of a cutter for a brush cutter, and maintains high strength even when heated when a plurality of blade portions are fixed to the rotary plate by brazing. Provide what is possible.

  The inventor of the present invention has increased the heat dissipating area by providing a through hole in the rotating plate, thereby conceiving to suppress the occurrence of temperature rise that affects the strength over a wide range due to heating during brazing. . However, since the formation of the through hole reduces not only the rotating plate but also the rigidity during use, the through hole cannot be formed without limitation.

The present invention has been made from such a viewpoint. That is, the present invention provides a rotating plate constituting a cutter for a brush cutter that is rotationally driven in a brush cutter, and has an outer peripheral edge along a circle centering on the rotation center axis thereof. In the outer peripheral edge portion, a plurality of positions intermittently arranged in the circumferential direction are formed with notches having a shape opened outward in the radial direction, and the rear side in the rotational direction of the portion sandwiching each notch from both sides in the circumferential direction A blade fixing portion where the blade portion is fixed to each other by brazing is set, and a plurality of heat radiation through holes are formed at positions between the blade fixing portions adjacent to each other in the circumferential direction. In addition, each of the heat radiating through holes has at least a part of the heat radiating through holes overlapping in the radial direction with respect to the blade portion fixing portions on both sides thereof, and is connected to the outer peripheral surface of the outer peripheral edge portion. Without this more Inside position in the radial direction has an independent shape from the outer peripheral surface, the rotary plate is to have a site than the heat dissipation through holes circumferentially continuous outside of the radial .

  Each heat radiating through hole having such a shape is fixed to each blade part fixing portion by brazing while avoiding a significant decrease in rigidity of the entire rotating plate due to the formation of the heat radiating through hole. In this case, it is possible to prevent a significant temperature increase from occurring over a wide range of the rotating plate, thereby suppressing a decrease in strength of the rotating plate.

  Specifically, the blade fixing portion is heated to a high temperature in order to braze the blade portion thereto, and the heat is generated between the blade fixing portion and the blade fixing portion adjacent thereto. The heat dissipation is efficiently released from the heat dissipation through hole (more precisely, from the edge of the rotating plate surrounding the heat dissipation through hole into the heat dissipation through hole). In addition, the heat radiating through hole has a shape that is interposed between the blade fixing portions adjacent to each other and at least a part of the heat radiating through hole overlaps with the blade fixing portion in the radial direction. It is possible to effectively suppress the transfer of the heat in the circumferential direction when the blade fixing portion is heated, and to limit the portion heated to a high temperature to a very local area. Therefore, it is possible to prevent the strength of the entire rotating plate from significantly lowering even if the heated blade portion fixing portion is locally somewhat softened.

  On the other hand, the heat radiating through hole is located between the blade fixing portions adjacent to each other, that is, at a position away from these blade fixing portions in the circumferential direction, and the radius of the heat radiating through hole is Since the portion of the rotating plate on the outer side in the direction is continuous in the circumferential direction, the heat radiating through hole has little influence on the rigidity of the outer peripheral portion of the rotating plate, particularly the rigidity in the vicinity of each blade portion fixing portion. Therefore, it is possible to ensure a good brushing function regardless of the existence of the heat radiating through hole.

  It is preferable that at least a part (preferably all) of the heat radiating through holes have a shape having a radial dimension larger than a circumferential dimension thereof. The heat-dissipating through hole having the shape has a relatively small circumferential dimension, and ensures a large distance in the circumferential direction between the heat dissipating through-hole and the blade fixing portions on both sides in the circumferential direction. It is possible to earn a large heat radiation area with a relatively large radial dimension.

  Specifically, as the heat radiating through hole, for example, a long hole extending in a direction in which the radial direction component is larger than the circumferential direction component is suitable.

  On the other hand, it is desirable that the notch corresponding to each blade portion fixing portion has a shape extending to a position on the inner side in the radial direction further than the blade portion fixing portion. The cutout having such a shape makes it possible to gain a heat radiation area that is extremely effective for heat radiation in the immediate vicinity of the fixed portion of the blade portion.

  Furthermore, it is preferable that the said notch has a shape which spreads in the circumferential direction inside the radial direction of the said opening rather than the width | variety of the opening of the said notch located on the outer peripheral surface of the said rotating plate. Thus, by reducing the width of the opening on the radially outer side of the notch, it is possible to prevent pebbles and the like from entering the notch and scattering by the rotation of the rotating plate, while on the inner side of the notch in the radial direction. It is possible to earn a large heat dissipation area by spreading the notch in the circumferential direction in the region.

  Regarding the relationship between each notch and each heat radiating through hole, the heat radiating through hole is located on the inner side in the radial direction with respect to the first hole portion overlapping with each notch in the radial direction and with each notch. And it is preferable to have the shape containing the 2nd hole part connected with the said 1st hole part. The second hole portion is located on the inner side in the radial direction from the notch, thereby avoiding a decrease in rigidity of the rotating plate in the circumferential direction, and further increasing the heat radiation area in addition to the heat radiation area of the first hole portion. Make it possible to increase.

In this case, the first hole portion has a shape extending along a radial direction of the rotating plate, the second hole portion, so as to be positioned on the front side in the rotational direction as it goes radially inward of the rotating plate It is desirable to include a portion having a shape extending in the direction of inclination. The first hole extends along the radial direction of the rotating plate, thereby ensuring a large size of the rotating plate between the first hole and the notches on both sides in the circumferential direction to ensure rigidity. Make it possible. Furthermore, the second hole portion, by including a portion having a shape extending in a direction inclined so as to be positioned in front of the radial direction of the rotating direction increases toward the inner side of the rotating plate, load blade portion undergoes during mowing It is possible to effectively disperse the stress generated by.

  The present invention also provides a cutter for a brush cutter that is rotationally driven in the brush cutter. The cutter for a brush cutter includes the rotating plate and a plurality of blade portions fixed to the blade portion fixing portions of the rotating plate by brazing.

  The present invention also provides a method for manufacturing the cutter for the brush cutter. This method includes a step of forming the rotating plate and a step of heating the blade portion fixing portion of the rotating plate one by one and fixing the blade portion to the heated blade portion fixing portion by brazing.

  As described above, according to the present invention, it is a rotary plate of a cutter for a brush cutter, and ensures rigidity for holding the shape when a plurality of blade portions are fixed to the rotary plate by brazing. What can be done is provided. Furthermore, there are provided a cutter for a brush cutter having excellent rigidity by using the rotary plate, and a method capable of manufacturing the cutter for a brush cutter while suppressing thermal deformation of the rotary plate.

It is a perspective view which shows the example of the brush cutter in which the cutter for brush cutters concerning embodiment of this invention is used. It is a top view of the cutter for the brush cutter. It is a top view which shows the outer peripheral part of the rotating plate of the cutter for said brush cutters. It is a top view which shows the state in which the blade part was fixed to the outer peripheral part of the rotary plate of the cutter for said brush cutter.

  Preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of a brush cutter in which a cutter 10 for a brush cutter according to an embodiment of the present invention is used. The brush cutter includes the brush cutter 10 and a brush cutter body 12 that rotationally drives the brush cutter 10.

  The brush cutter main body 12 includes a main body shaft 14 extending in one direction, a prime mover 16 provided at the upper end of the main body shaft 14, and a gear case 18 provided at the lower end of the main body shaft 14. The main body shaft 14 incorporates a mechanism for transmitting the power generated by the prime mover 16 to the gear case 18, and the gear case 18 has an output shaft that is rotationally driven by the power.

  The cutter 10 for the brush cutter is detachably connected to the output shaft of the gear case 18 and exhibits a brush cutting function by being rotationally driven integrally with the output shaft in the connected state. Specifically, the cutter 10 for a brush cutter includes a rotating plate 20 shown in FIGS. 2 to 4 and a plurality of blade portions 30 shown in FIGS. 2 and 4. While being fixed to the rotating plate 20, the rotating plate 20 is connected to the output shaft.

  The rotating plate 20 has a disk shape, and a central portion thereof is coupled to the output shaft. Specifically, the rotating plate 20 according to this embodiment has a circular inner portion 20A and an outer peripheral portion 20B positioned on the radially outer side, and the output shaft is provided at the center of the inner portion 20A. A central hole 21 through which can be inserted is formed. The rotary plate 20 according to this embodiment is formed of special steel suitable for a tool, for example, SK5, but the material is not particularly limited.

  The outer peripheral portion 20B has an annular shape surrounding the inner portion 20A. The outer peripheral portion 20 </ b> B has an outer peripheral surface 23 that is concentric with the center of the central hole 21. Notches 24 are respectively formed at a plurality of positions aligned in the circumferential direction in the outer peripheral portion 20B. Each notch 24 has a shape opened outward in the radial direction.

  As shown in FIGS. 3 and 4, a blade is disposed on the rear side in the rotational direction (the direction of arrow A shown in FIGS. 3 and 4) of the outer peripheral portion 20 </ b> B sandwiching the notches 24 from both sides in the circumferential direction. A part fixing part 25 is set, and each blade part 30 is fixed to the blade part fixing part 25.

  Each of the blade portions 30 is made of, for example, a cemented carbide and has a rectangular parallelepiped body portion 32 and a blade edge 34. As shown in FIG. 3, a notch 26 having a shape corresponding to the main body portion 32 of the blade portion 30 is formed in the blade portion fixing portion 25, and the main body portion 32 is fitted in the notch 26. The boundary portion between the outer surface of the main body portion 32 and the inner surface of the blade portion fixing portion 25 that defines the notch 26 is brazed with a brazing material (for example, silver brazing), whereby the main body portion 32 is fixed to the blade. It is fixed to the part fixing part 25. In this fixed state, the blade portion 30 is fixed to the outer peripheral portion 20B in a posture inclined with respect to the radial direction so that the blade edge 34 faces the front side in the rotation direction.

  Further, as a feature of the rotary plate 20 of the cutter 10 for a brush cutter, a plurality of heat radiating through holes 27 are formed. Each heat radiating through hole 27 is formed at a position between the blade adhering portions 25 adjacent to each other in the circumferential direction. Each heat radiating through hole 27 has a shape in which at least a part of the heat radiating through hole 27 overlaps in the radial direction with respect to the blade portion fixing portion 25 on both sides thereof, and the shape 28 is continuous in the circumferential direction. . That is, the heat radiating through hole 27 is not connected to the outer peripheral surface 23 of the outer peripheral portion 20 </ b> B and is independent from the outer peripheral surface 23 at a position inside thereof.

  Each of the heat radiating through holes 27 having such a shape prevents the blade portion 30 from being attached to each blade portion fixing portion 25 while avoiding a significant decrease in the rigidity of the entire rotating plate 20 due to the formation of the heat radiating through holes 27. When fixing by attaching, it is possible to prevent a significant temperature rise over a wide range of the rotating plate 20, thereby suppressing a reduction in strength of the rotating plate 20.

  Specifically, the cutter 10 for the brush cutter forms the rotating plate 20 by, for example, heat treatment such as press working and subsequent quenching, and heats the blade portion fixing portion 25 of the rotating plate 20 one by one. The blade portion 30 is brazed to the heated blade portion fixing portion 25 (specifically, the main body portion 32 of the blade portion 30 is fitted in the notch 26 formed in the blade portion fixing portion 25) And a brazing process is performed by providing a molten brazing material to a boundary portion between the blade portion fixing portion 25 and the main body portion 32). Therefore, the heat applied to the blade fixing portion 25 is spread between the blade fixing portion 25 and the blade fixing portion 25 adjacent thereto before spreading over a wide range of the rotary plate 20. 27 (more accurate From the edge 29 of the rotary plate 20 surrounding the heat radiating through holes 27 to the heat dissipation through-hole 27) escapes efficiently. Moreover, the heat radiating through hole 28 has a shape that is interposed between the blade fixing portions 25 adjacent to each other and at least a part of the heat radiating through hole 25 overlaps the blade fixing portion 25 in the radial direction. Therefore, when the one blade portion fixing portion 25 is heated, the heat is effectively suppressed from being transmitted in the circumferential direction, and thereby the portion of the rotating plate 20 that is at a high temperature is extremely locally suppressed. Is possible. Therefore, even if the heated blade portion fixing part 25 is locally somewhat softened, it is possible to prevent the strength of the entire rotating plate 20 from significantly lowering.

  On the other hand, the heat radiating through hole 27 is located between the blade fixing portions 25 adjacent to each other, that is, at a position away from the blade fixing portions 25 in the circumferential direction, and the heat radiating through holes 27 are disposed. Since the portion 28 of the rotating plate 20 radially outside the hole 27 has a shape that is continuous in the circumferential direction, the heat radiating through hole 27 has rigidity in the outer peripheral portion of the rotating plate 20, particularly in the vicinity of each blade portion fixing portion 25. The effect on the rigidity is small. Therefore, it is possible to ensure a good brushing function regardless of the existence of the heat dissipation through hole 27.

  Further, in this embodiment, the shape of each notch 24 and each heat radiating through hole 27 is set so as to give the rotating plate 20 higher heat radiation performance.

  Specifically, the notch 24 given to each blade portion fixing portion 25 has a more effective heat dissipation area for heat dissipation in the immediate vicinity of the blade portion fixing portion 25, so that the radius is further increased than the blade portion fixing portion 25. It has a shape that extends to a position inside the direction. Further, the notch 24 has an outer portion 24a connected to the outer peripheral surface 23 of the outer peripheral portion 20B and a back side portion 24b located on the inner side in the radial direction, and each has a different shape. That is, the circumferential dimension of the outer portion 24a is substantially the same as the width of the opening of the notch 24 on the outer circumferential surface 23 (more precisely, the width W of the opening formed immediately next to the blade edge 34). On the other hand, the back side portion 24b has a shape that expands in the circumferential direction inside the opening in the radial direction with respect to the width W (in the present embodiment, a substantially circular shape having a diameter larger than the width W). There is no. Thus, by reducing the width W of the opening on the radially outer side of the notch 24 (for example, about 2 mm), it is possible to prevent pebbles and the like from entering the notch 24 and scattering due to the rotation of the rotating plate 20. On the other hand, it is possible to earn a large heat radiation area by spreading the back side portion 24b of the notch 24 in the circumferential direction in a region radially inward of the opening.

  On the other hand, the heat radiating through hole 27 has a shape in which the dimension in the radial direction is larger than the dimension in the circumferential direction of the heat radiating through hole 27. Specifically, it is a long hole whose radial component is larger in the direction than the circumferential component. The heat radiating through hole 27 having such a shape increases the circumferential distance between the heat radiating through hole 27 and the blade fixing portions 25 on both sides in the circumferential direction due to the relatively small circumferential dimension. It is possible to earn a large heat radiation area by a relatively large radial dimension while maintaining and maintaining high rigidity.

  More specifically, the heat radiating through hole 27 has a first hole portion 27a that overlaps with each notch 24 in the radial direction and a radially inner side with respect to each notch 24 as a preferable shape that cooperates with the notch 24. And a second hole part 27b connected to the first hole part 27a. In addition to the heat radiation area of the first hole 27a, the second hole 27b is located on the inner side in the radial direction than the notch 24, thereby avoiding a decrease in rigidity of the rotating plate 20 in the circumferential direction. It is possible to further increase the heat dissipation area.

  Further, the first hole portion 27a according to this embodiment has a shape extending along the radial direction of the rotating plate 20, whereas the second hole portion 27b is formed in the radial direction of the rotating plate 20. On the other hand, it has a shape extending in a direction inclined to the front side in the rotation direction. The first hole portion 27a extends along the radial direction of the rotating plate 20, thereby ensuring a large dimension of the rotating plate 20 between the first hole portion 27a and the notches 24 on both sides in the circumferential direction. It is possible to ensure rigidity. Further, the second hole portion 27b has a shape extending in a direction inclined to the front side in the rotational direction with respect to the radial direction of the rotating plate 20, thereby effectively applying stress caused by the load that the blade portion 30 receives during mowing. Can be dispersed.

  The present invention is not limited to the embodiment described above. In particular, various modifications can be made to the shapes of the heat radiating through holes 27 and the notches 24.

  For example, the heat dissipation through hole 27 may be circular. However, in this case, if the diameter of the heat radiating through hole 27 is reduced, it is difficult to obtain a high heat dissipation performance. Conversely, if the diameter is increased, the rigidity of the entire rotating plate 20 is lowered, so that setting of the diameter is difficult. In this way, the shape in which the dimension in the diameter direction is larger than the dimension in the circumferential direction, especially the shape of the long hole extending in the direction in which the radial component is large, makes it easy to achieve both high heat dissipation performance and sufficient rigidity of the entire rotating plate 20. To.

  Further, even when the heat radiating through hole 27 is a long hole, the shape is not limited to the shape bent between the first hole portion 27a and the second hole portion 27b as described above. The thing and the shape where the whole curved with a uniform curvature may be sufficient. In any case, the second hole 27b positioned radially inward of the notch 24 has a shape inclined to the front side in the rotation direction, so that stress concentration can be effectively reduced.

  The inner side 24b of each notch 24 is not necessarily circular. By increasing the circumferential dimension of the back side portion 24b, the heat radiation area can be effectively obtained. However, the fact that the back side portion 24b is circular has an advantage that stress concentration can be effectively reduced.

DESCRIPTION OF SYMBOLS 10 Crusher cutter 20 Rotating plate 20A Inner part 20B Outer part 23 Outer part 24 Outer part 24 Notch 24a Outer part of the notch 24b Outer side part of the notch 25 Blade part fixing part 27 Radiating through hole 27a First hole part 27b Second hole Part 28 The part of the rotating plate outside in the radial direction from the heat radiating through hole 29 Edge of the heat radiating through hole 30 Blade part 34 Cutting edge

Claims (9)

A rotary plate that constitutes a cutter for a brush cutter that is rotationally driven in a brush cutter, and has an outer peripheral edge along a circle centered on the rotation center axis, and intermittently circumferentially at the outer peripheral edge. Notches having a shape opened radially outward are formed at a plurality of positions arranged side by side, and the blades are brazed to the portions on the rear side in the rotational direction among the portions sandwiching each notch from both sides in the circumferential direction. A blade fixing portion to be fixed is set, and a plurality of heat radiating through holes are formed at positions between blade fixing portions adjacent to each other in the circumferential direction, and each heat radiating through hole is formed. Is that at least a part of the through-hole for heat dissipation overlaps in the radial direction with respect to the blade portion fixing part on both sides thereof, and does not lead to the outer peripheral surface of the outer peripheral edge portion , and the inner side in the radial direction than this The outer peripheral surface at the position Has et independent shape, the rotating plate, than the heat radiating through holes to have a site for continuous outward in the circumferential direction of the radial direction, the rotating plate of the cutter for mowing machine.   The rotary plate of the cutter for a brush cutter according to claim 1, wherein at least a part of the heat radiating through hole of the heat radiating through hole has a shape having a radial dimension larger than a circumferential dimension thereof. Cutter rotating plate for brush cutter.   The rotary plate of the cutter for a brush cutter according to claim 2, wherein at least a part of the heat radiating through hole of the heat radiating through hole is a long hole extending in a direction in which a radial component is larger than a circumferential component. Rotating plate of cutter for brush cutter.   It is a rotary plate of the cutter for brush cutters in any one of Claims 1-3, Comprising: The notch corresponding to each said blade part adhering site | part is further to the position inside the radial direction rather than the said blade part adhering site | part. A rotary plate for a cutter for a brush cutter having an extending shape.   The rotary plate of the cutter for a brush cutter according to claim 4, wherein the notch is arranged in a circumferential direction on a radially inner side of the opening than a width of an opening of the notch located on an outer peripheral surface of the rotary plate. A rotating plate of a cutter for a brush cutter having a widening shape.   It is a rotary plate of the cutter for brush cutters in any one of Claims 1-5, Comprising: The said through-hole for heat radiation is more than the 1st hole part which overlaps with each said notch about a radial direction, and each said notch. A rotary plate of a cutter for a brush cutter, having a shape including a second hole portion located inside in a radial direction and connected to the first hole portion. The rotary plate of the cutter for a brush cutter according to claim 6, wherein the first hole has a shape extending along a radial direction of the rotary plate, and the second hole has a radius of the rotary plate. includes a portion having a shape extending in a direction inclined so as to be positioned on the front side as in the rotational direction toward the inside direction, the rotating plate of the cutter for mowing machine.   A cutter for a brush cutter that is rotationally driven in a brush cutter, wherein the cutter is fixed to the rotating plate according to any one of claims 1 to 7 and each blade portion fixing portion of the rotating plate by brazing. A cutter for a brush cutter comprising a plurality of blade portions.   A method for manufacturing a cutter for a brush cutter that is rotationally driven in a brush cutter, the step of forming the rotary plate according to any one of claims 1 to 7, and a blade portion fixing portion of the rotary plate And a step of fixing the blade portion to the heated blade portion fixing portion by brazing one by one.

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