Rotor, brush cutter, and method for manufacturing rotor

Abstract

Provided are a rotor in which a metal fitting and a main body part are firmly coupled, and a brush cutter provided with the rotor. The rotor (1) comprises a metal fitting (2) and a resin main body partn (3) molded integrally with the metal fitting (2). The metal fitting (2) includes an insertion hole (20) and an annular part (22) positioned so as to surround the insertion hole (20). The annular part (22) has a first surface (221) and a second surface (222) which face opposite sides to each other in an axial direction (D1). A plurality of protrusions (26) are formed on the first surface (221) at intervals in the circumferential direction (D2) of the annular part (22). Each of the plurality of protrusions (26) is embedded in the main body part (3).

Description

Rotating body, lawn mower, and method for manufacturing a rotating body

[0001] The present disclosure relates to a rotating body, a lawn mower, and a method for manufacturing a rotating body.

[0002] A rotating body attached to a lawn mower body is conventionally known (see Patent Document 1). The rotating body is attached to a drive rod of the lawn mower body and is rotationally driven integrally with the drive rod. The rotating body includes a metal fitting and a resin main body portion coupled to the metal fitting. A user can mow grass, for example, using a rotary blade sandwiched between the metal fitting of the rotating body and the lawn mower body.

[0003] Japanese Patent Application Laid-Open No. 2007-252213

[0004] The problem to be solved by the present disclosure is to provide a rotating body in which a metal fitting and a main body portion are firmly coupled and a lawn mower including the same.

[0005] A rotating body according to one aspect of the present disclosure includes a metal fitting fixed to a drive rod of a lawn mower body and a resin main body portion integrally formed with the metal fitting. The metal fitting includes an insertion hole formed therethrough for inserting the drive rod and an annular portion positioned so as to surround the insertion hole. The annular portion has a first surface and a second surface facing opposite sides in the axial direction of the insertion hole. A plurality of protrusions are formed on the first surface at intervals in the circumferential direction of the annular portion, and each of the plurality of protrusions is embedded in the main body portion.

[0006] A lawn mower according to one aspect of the present disclosure includes the rotating body and the lawn mower body.

[0007] A method for manufacturing a rotating body according to one form of the present disclosure is a method for manufacturing the rotating body, and the main body portion coupled to the metal fitting is formed by insert molding.

[0008] A method for manufacturing a rotating body according to another form of the present disclosure is a method for manufacturing the rotating body, and the plurality of protrusions are formed by punching a punch on the second surface, and at that time, a flange is formed by crushing a tip portion of at least one of the protrusions.

[0009] A further embodiment of the present disclosure is a method for manufacturing a rotating body, comprising the steps of forming the plurality of protrusions by striking a punch against the second surface, thereby crushing the tip of at least one of the protrusions, and forming a flange into a flared shape by striking the crushed tip of the at least one protrusion with a punch.

[0010] Figure 1 is a perspective view of a brush cutter equipped with a rotating body of the first embodiment. Figure 2 is a cross-sectional view of the main part of the brush cutter, including the rotating body. Figure 3 is a perspective view of the rotating body. Figure 4 is a plan view of the rotating body. Figure 5 is a plan view of the fittings provided on the rotating body. Figure 6 is a cross-sectional view taken along line A-A in Figure 5. Figure 7 is a cross-sectional view taken along line B-B in Figure 5. Figure 8 is a cross-sectional view of the main part illustrating the first step. Figure 9 is a cross-sectional view of the main part illustrating the second step. Figure 10 is a plan view of the rotating body of the second embodiment. Figure 11 is a cross-sectional view of the rotating body of the second embodiment. Figure 12 is a plan view of the rotating body of the third embodiment.

[0011] 1. One Embodiment: A rotating body, a brush cutter, and a method for manufacturing a rotating body according to an embodiment of the present disclosure will be described based on the attached drawings.

[0012] However, the embodiments described below are only one of many embodiments of this disclosure, and various modifications are possible depending on the design, etc., as long as the objectives of this disclosure are achieved. Also, the figures showing the embodiments below are schematic diagrams and do not necessarily reflect actual dimensions.

[0013] (Brush cutter) As shown in Figures 1 and 2, the brush cutter 9 of the first embodiment comprises a brush cutter body 90 and a rotating body 1 fixed to the tip portion of the brush cutter body 90.

[0014] (Brush cutter body) The brush cutter body 90 comprises a main shaft 94, a drive rod 95 extending from the tip of the main shaft 94, and a support 96 coupled to the outer surface of the drive rod 95 so as to rotate integrally with the drive rod 95. The rotating blade 8 is detachably attached to the drive rod 95 using a rotating body 1.

[0015] The brush cutter body 90 further comprises a handle 97 attached to the middle of the main shaft 94 and an engine 98 attached to the rear end of the main shaft 94. It is also preferable that the brush cutter body 90 be equipped with an electric motor instead of the engine 98.

[0016] In the brush cutter 9 of the first embodiment, the output of the engine 98 is transmitted to the drive rod 95 via the main shaft 94. The rotating body 1 is fixed to the drive rod 95. When the drive rod 95 is rotated, the rotating body 1 is rotated together with the drive rod 95. At this time, the rotating blade 8 is rotated together with the rotating body 1.

[0017] (Rotating body) The rotating body 1 comprises a metal fitting 2 and a resin body 3 molded integrally with the metal fitting 2. The metal fitting 2 and the body 3 are joined by insert molding.

[0018] (Metal fittings) Metal fittings 2 are components through which the drive rod 95 of the brush cutter 9 is inserted and fixed to the drive rod 95 using a tightening means. The tightening means is, for example, a nut 92 that is coupled to the outer circumferential surface of the tip of the drive rod 95.

[0019] The fitting 2 is configured to detachably clamp the rotating blade 8 between itself and the receiving device 96 provided on the brush cutter body 90, and to rotate the rotating blade 8 together with the drive rod 95.

[0020] The fitting 2 includes a through hole 20 formed through the center of the fitting 2 for inserting the drive rod 95, an annular portion 22 positioned to surround the through hole 20 around its entire circumference, and a second annular portion 23 positioned between the annular portion 22 and the through hole 20. The second annular portion 23 is positioned to surround the through hole 20 around its entire circumference.

[0021] (Annular portion) The annular portion 22 of the fitting 2 has a first surface 221 and a second surface 222 that face opposite each other in the axial direction D1 of the insertion hole 20 (see Figure 6, etc.). Hereinafter, the side that the first surface 221 faces in the axial direction D1 will be referred to as the "first side", and the side that the second surface 222 faces in the axial direction D1 will be referred to as the "second side".

[0022] The first surface 221 has an annular shape surrounding the insertion hole 20. The second surface 222 also has an annular shape surrounding the insertion hole 20.

[0023] Multiple through holes 24 are formed in the annular portion 22 of the metal fitting 2 at intervals in the circumferential direction D2 (see Figure 5, etc.). The circumferential direction D2 is the circumferential direction of the metal fitting 2 as a whole, which forms an annular shape, and is also the circumferential direction of the annular portion 22 and the second annular portion 23.

[0024] The multiple through holes 24 are eight through holes 24 formed at equal intervals in the circumferential direction D2. Each through hole 24 is a stepped through hole 24. In each through hole 24, the opening area on the second surface 222 is larger than the opening area on the first surface 221. Each through hole 24 penetrates the annular portion 22 in the axial direction D1. Each through hole 24 includes a small diameter portion 241, which is the first side portion, and a large diameter portion 242, which is the second side portion. The small diameter portion 241 and the large diameter portion 242 are located in a straight line in the axial direction D1. The large diameter portion 242 is formed such that the diameter increases towards the second side portion (i.e., the portion closer to the second surface 222).

[0025] In the first embodiment of the rotating body 1, the resin 30 (see Figure 2) that constitutes a part of the main body 3 is filled into each through hole 24, thereby firmly bonding the metal fitting 2 to the main body 3, and preventing the main body 3 and the metal fitting 2 from separating when a large external force is applied to the rotating body 1.

[0026] As shown in Figure 2, the first surface 221 of the annular portion 22 is covered by the main body portion 3. As shown in Figure 4, the second surface 222 of the annular portion 22 is exposed and not covered by the main body portion 3.

[0027] (Multiple protrusions) Multiple protrusions 26 are formed on the first surface 221 of the annular portion 22 at intervals in the circumferential direction D2 of the annular portion 22. The multiple protrusions 26 are eight protrusions 26 formed at equal intervals in the circumferential direction D2.

[0028] In the rotating body 1 of the first embodiment, each of the multiple protrusions 26 that protrude from the first surface 221 of the annular portion 22 is embedded in the resin body portion 3, thereby further firmly fixing the metal fitting 2 and the body portion 3.

[0029] The following describes the common structure of the multiple protrusions 26.

[0030] The outer circumferential surface of the projection 26 includes an uneven portion 262. The uneven portion 262 is composed of a flange 264 provided on the projection 26. The flange 264 has a shape that widens radially outward from the projection 26. The flange 264 is provided around the entire circumference of the projection 26.

[0031] In the rotating body 1 of the first embodiment, the flange 264 of the projection 26 has a flared shape, which widens towards the tip. In other words, the flared shape is a trumpet shape.

[0032] In the first embodiment of the rotating body 1, the entire projection 26 has a flared shape, which widens towards the tip. The flared projection 26 is formed to be thinner towards the tip.

[0033] A cavity 260 is provided at the center of the projection 26. The cavity 260 is open at the tip of the projection 26. The cavity 260 is open to the first side in the axial direction D1. The cavity 260 is formed to be larger in diameter closer to the tip of the projection 26.

[0034] As shown in Figure 7, in a cross-section perpendicular to the first surface 221 of the metal fitting 2, the outer surface of the projection 26 is curved such that the angle with the central axis of the projection 26 increases towards the tip.

[0035] (Multiple recesses) Multiple recesses 28 are formed on the second surface 222 of the annular portion 22, spaced apart in the circumferential direction D2 of the annular portion 22. Each of the multiple recesses 28 is located on the back side of each of the multiple protrusions 26 on the annular portion 22. In other words, each of the multiple recesses 28 is located on the back side of each of the multiple protrusions 26 on the annular portion 22 in a one-to-one correspondence.

[0036] It is preferable that one of the multiple recesses 28 and one of the multiple protrusions 26 corresponding to one of the recesses 28 are arranged so that their central axes coincide. The multiple recesses 28 are eight recesses 28 formed at equal intervals in the circumferential direction D2.

[0037] The following describes the common structure of the multiple recesses 28.

[0038] The recess 28 is a recess with a circular cross-section. The cross-section here is perpendicular to the axial direction D1. The central axis of the recess 28 coincides with the central axis of the projection 26 located on the back side of the recess 28 in the annular portion 22. The diameter of the recess 28 is smaller than the outer diameter of the projection 26 located on the back side of the recess 28 in the annular portion 22.

[0039] As shown in Figure 5, etc., the second surface 222 of the annular portion 22 has a plurality of recesses 28 and a plurality of through holes 24 arranged alternately in the circumferential direction D2 surrounding the insertion hole 20.

[0040] In other words, on the second surface 222 of the annular portion 22, multiple recesses 28 and multiple through holes 24 on the second surface 222 are alternately arranged in the circumferential direction D2. Each of the recesses 28 is circular in shape. Each of the through holes 24 on the second surface 222 is circular in shape. The opening area of ​​each of the recesses 28 is smaller than the opening area of ​​any of the through holes 24. The opening diameter of each of the recesses 28 is smaller than the opening diameter of any of the through holes 24.

[0041] Of the multiple through holes 24, one corresponding recess 28 is located between two through holes 24 that are adjacent to each other in the circumferential direction D2. The two through holes 24 that are adjacent to each other in the circumferential direction D2, and the one recess 28 located between these two through holes 24, are positioned at equal intervals in the circumferential direction D2.

[0042] Of the multiple recesses 28, one of the multiple through holes 24 is located between two recesses 28 that are adjacent to each other in the circumferential direction D2. The two recesses 28 that are adjacent to each other in the circumferential direction D2, and the one through hole 24 located between these two recesses 28, are positioned at equal intervals in the circumferential direction D2.

[0043] (Raised portion) On the second surface 222 of the annular portion 22, a raised portion 29 is formed that is more raised than the rest of the second surface 222, surrounding the insertion hole 20. The raised portion 29 is configured to contact the rotating blade 8 around its entire circumference. The rotating blade 8 is held between the raised portion 29 of the metal fitting 2 and the receiving device 96 of the brush cutter body 90.

[0044] The raised portion 29 is divided in the circumferential direction D2 by a plurality of through holes 24. In other words, the raised portion 29 is composed of a plurality of arc-shaped raised portions 291 that are positioned at intervals from each other in the circumferential direction D2.

[0045] The plurality of arc-shaped raised portions 291 and the plurality of through holes 24 are alternately positioned in the circumferential direction D2. Each of the plurality of arc-shaped raised portions 291 is positioned between two through holes 24 that are adjacent to each other in the circumferential direction D2 among the plurality of through holes 24.

[0046] The plurality of recesses 28 are provided so as to open in the raised portion 29. Each of the plurality of recesses 28 is provided so as to open at the intermediate portion in the circumferential direction D2 of the corresponding arc-shaped raised portion 291 among the plurality of arc-shaped raised portions 291. The plurality of recesses 28 and the plurality of arc-shaped raised portions 291 correspond to each other one-to-one.

[0047] (Second annular portion) The second annular portion 23 is located on the first side in the axial direction D1 with respect to the annular portion 22. In other words, the second annular portion 23 is located on the side where the main body portion 3 is positioned with respect to the fitting 2 in the axial direction D1.

[0048] The through hole at the center of the second annular portion 23 is the insertion hole 20 that penetrates in the axial direction D1.

[0049] (Inclined wall portion) Further, the fitting 2 includes an inclined wall portion 21. The inclined wall portion 21 is an annular portion located between the annular portion 22 and the second annular portion 23. The inclined wall portion 21 is inclined over the entire circumference so as to connect the annular portion 22 and the second annular portion 23. The inclination of the inner peripheral surface of the inclined wall portion 21 is uniform throughout.

[0050] The inner peripheral surface of the inclined wall portion 21 has a circular cross-sectional shape. The cross-section here is a cross-section orthogonal to the axial direction D1. Among the inclined wall portion 21, the portion on the first side in the axial direction D1 has a smaller cross-sectional shape.

[0051] (Main body portion) As shown in FIGS. 2 and 3, the main body portion 3 includes a recess 32 in which the tip portion of the drive rod 95 is accommodated, and a grounding portion 35 formed so as to surround the recess 32.

[0052] The recess 32 of the main body 3 accommodates the portion of the drive rod 95 that protrudes from the insertion hole 20 of the fitting 2, and the nut 92 that is screwed onto this portion. The second annular portion 23 of the fitting 2 is exposed on the bottom surface of the recess 32.

[0053] The contact portion 35 is configured to slide against the ground E. The outer circumferential surface of the contact portion 35 is a contact surface 352 that is inclined such that the radially outer portion is located on the second side of the axial direction D1.

[0054] (Method for manufacturing a rotating body) The method for manufacturing the rotating body 1 of the first embodiment will be described below.

[0055] The method for manufacturing the rotating body 1 of the first embodiment comprises a first molding step of molding the metal fitting 2, and a second molding step of molding the main body portion 3 connected to the metal fitting 2 by insert molding.

[0056] (First molding process) The first molding process includes a main process for molding the main part of the metal fitting 2, and an additional process for molding a plurality of protrusions 26 and a plurality of recesses 28 of the metal fitting 2.

[0057] In the main process, a work-in-progress 2A of the metal fitting 2 is formed by press working on a flat sheet metal. Press working here is, in other words, deep drawing. The flat sheet metal that forms the base of the metal fitting 2 is, for example, a flat, annular sheet metal.

[0058] In the work-in-progress 2A of the metal fitting 2 formed in the main process, the multiple protrusions 26 and multiple recesses 28 have not been formed. In other words, in the first process, the portion of the metal fitting 2 excluding the multiple protrusions 26 and multiple recesses 28 is formed. In the work-in-progress 2A of the metal fitting 2, the through hole 20, the slanted wall portion 21, the annular portion 22, the second annular portion 23, the through hole 24, and the raised portion 29 have already been formed.

[0059] In the additional steps, the annular portion 22 formed on the work-in-progress 2A of the metal fitting 2 is subjected to press working to further form a plurality of protrusions 26, each having a flange 264, and a plurality of recesses 28. The plurality of protrusions 26, each having a flange 264, are formed by the first and second steps described below.

[0060] In the first step, which is included in the additional process, as shown in Figure 8, a punch 51 is struck against the second surface 222 of the annular portion 22 and pressed to form a projection 26 that protrudes from the first surface 221. The punch 51 is struck against the raised portion 29 of the second surface 222.

[0061] In the first step, it is preferable that the die 56 supporting the first surface 221 of the annular portion 22 is provided with a recess 563. The punch 51 pushes a part of the annular portion 22 outwards in the first direction D1, forming a projection 26 on the first surface 221 of the annular portion 22 and a recess 58 on the second surface 222 of the annular portion 22. At this time, the tip of the projection 26 hits the bottom surface of the recess 563 and is crushed, forming a flange 264 on the tip of the projection 26 (see Figure 9). At this stage, the flange 264 is not flared.

[0062] In the second step, which is an additional step, as shown in Figure 9, the flange 264 is formed into a flared shape by further pressing the flattened tip of the projection 26 with the punch 52. In other words, the flared flange 264 of the projection 26 of the metal fitting 2 on the rotating body 1 of the first embodiment is formed by going through the above first and second steps. It is preferable that the punch 52 is a different punch with a smaller diameter than the punch 51 used in the first step.

[0063] In Figure 9, the punch 52 is positioned below the work-in-progress 2A of the metal fitting 2, but it is also preferable to perform the second step with this positional relationship inverted. That is, after performing the first step, it is also preferable to invert the work-in-progress 2A of the metal fitting 2 and place it on the die 57, and then strike the work-in-progress 2A of the metal fitting 2 with the punch 52 from above.

[0064] In the second step, it is preferable that the die 57 supporting the second surface 222 of the annular portion 22 is provided with a protrusion 573 that fits into the recess 28. As the projection 26 is further crushed between the protrusion 573 of the die 57 and the punch 52 that strikes it, a cavity 260 is formed in the central part of the projection 26, and the flange 264 of the projection 26 is formed into a flared shape.

[0065] (Second molding process) The second molding process is carried out after the first molding process.

[0066] In the second molding process, a resin body portion 3, which is firmly bonded to the metal fitting 2, is molded by insert molding. At this time, in addition to the resin 30 that constitutes a part of the body portion 3 being filled into each of the multiple stepped through holes 24, multiple protrusions 26, each having a flared flange 264, are embedded in the resin body portion 3, so that the metal fitting 2 and the body portion 3 are very firmly bonded.

[0067] (Effects) According to the rotating body 1 of the first embodiment described above, the metal fitting 2 and the main body 3 are joined much more firmly than in the conventional technology. For example, in a test conducted at the Mie Prefectural Industrial Research Institute in Japan using an Amsler-type universal testing machine, the results showed that the metal fitting 2 and the main body 3 of the rotating body 1 of the first embodiment are joined much more firmly than in the conventional rotating body. The details are as follows.

[0068] In the first embodiment, a load in the axial direction D1 was applied to the fitting 2 of the rotating body 1, and the load at which the rotating body 1 broke was measured. The rotating body 1 was boiled for one hour, and the test was conducted three days later. A total of 16 tests were performed, and it was confirmed that the rotating body 1 broke at an average load of 5733 N. In all cases, before the fitting 2 detached from the main body 3, the main body 3 broke, and the rotating body 1 broke as a result of the breakdown of the main body 3. In other words, in the rotating body 1 of the first embodiment, the connection between the fitting 2 and the main body 3 was maintained until the main body 3 itself broke.

[0069] In tests against conventional rotating bodies, a conventional rotating body was used in which only the multiple protrusions 26 of the fitting 2 were removed from the rotating body 1 of the first embodiment. In this case, tests conducted under the same conditions confirmed that the rotating body 1 broke under an average load of 2646 N. In both cases, the rotating body 1 broke because the fitting 2 detached from the main body 3 before the main body 3 broke.

[0070] From the above, it was confirmed that in the rotating body 1 of the first embodiment, the fitting 2 and the main body 3 are very firmly connected compared to the conventional technology, as the fitting 2 is provided with multiple protrusions 26.

[0071] 2. The second embodiment of the rotating body 1 will be described based on Figures 10 and 11. In the following description, components similar to those in the first embodiment will be denoted by the same reference numerals and detailed explanations will be omitted, while components that differ from the first embodiment will be described.

[0072] The rotating body 1 of the second embodiment comprises a fitting 2 having the same configuration as in the first embodiment, and a main body 3 made of synthetic resin that is coupled to the fitting 2. The main body 3 comprises an upper body 31 that is coupled to the fitting 2, a grounding portion 35 located below the upper body, and a flange portion 38 located between the upper body 31 and the grounding portion 35.

[0073] In the second embodiment of the rotating body 1, the resin 30 that constitutes a part of the upper body 31 of the main body 3 is filled into each through hole 24 of the metal fitting 2. In addition, each projection 26 of the metal fitting 2 is embedded in the upper body 31. The ground contact portion 35 is an annular ground contact portion with a through hole in the center that constitutes a part of the recess 32.

[0074] The flange portion 38 has a larger diameter than the upper body 31 and the ground contact portion 35. The flange portion 38 has a smaller diameter than the rotating blade 8.

[0075] Furthermore, the main body 3 is equipped with a locking structure for which the linear cutter 6 is locked. Multiple outlets 36 are provided on the outer circumferential surface of the upper body 31 from which the linear cutter 6, locked in the locking structure, is pulled out. The linear cutter 6 pulled out from the outlets 36 is located above the flange portion 38.

[0076] In the second embodiment of the rotating body 1, it is possible to mow grass using a rotating blade 8 clamped between the fitting 2 and the receiving part 96 of the brush cutter body 90, and a linear cutter 6 attached to the main body 3. It is also possible to mow grass using only the linear cutter 6 without clamping the rotating blade 8 between the fitting 2 and the receiving part 96 of the brush cutter body 90. It is also possible to mow grass using only the rotating blade 8 clamped between the fitting 2 and the receiving part 96 of the brush cutter body 90.

[0077] In the second embodiment of the rotating body 1, the upper body 31, flange portion 38, and ground portion 35 are molded separately, but it is also preferable that the upper body 31 be molded integrally with the flange portion 38. It is also preferable that the ground portion 35 be molded integrally with the flange portion 38. Furthermore, it is also preferable that the upper body 31, flange portion 38, and ground portion 35 be molded integrally.

[0078] 3. The rotating body 1 of the third embodiment will be described based on Figure 12 of the third embodiment. In the following description, components similar to those of the first embodiment will be denoted by the same reference numerals and detailed explanations will be omitted, while components that differ from the first embodiment will be described in detail.

[0079] The rotating body 1 of the third embodiment comprises a metal fitting 2 having the same configuration as in the first embodiment, a main body 3 made of synthetic resin that is coupled to the metal fitting 2, and a bobbin 4 that is detachably attached to the main body 3 and rotates integrally with the main body 3.

[0080] The main body 3 has a cylindrical portion 33 to which the metal fitting 2 is attached, a flange-shaped grounding portion 35 extending radially outward from the lower part of the cylindrical portion 33, and a plurality of pull-out holes 37 formed through the grounding portion 35.

[0081] The bobbin 4 has an inner circumferential surface that detachably contacts the outer circumferential surface of the cylindrical portion 33, and an outer circumferential surface around which the flexible linear cutter 7 is wound. Both ends of the linear cutter 7 wound around the outer circumferential surface of the bobbin 4 are pulled out radially outward through two of the multiple pull-out holes 37.

[0082] The bobbin 4 further includes a plurality of elastic pieces 43 that elastically press against the outer circumferential surface of the cylindrical portion 33, and a plurality of grooves 45 that allow these elastic pieces 43 to bend radially outward.

[0083] In the third embodiment of the rotating body 1, it is possible to cut grass using a rotating blade 8 clamped between the fitting 2 and the receiving part 96 of the brush cutter body 90, and a linear cutter 7 attached to the main body 3 via a bobbin 4. It is also possible to cut grass using only the linear cutter 7 without clamping the rotating blade 8 between the fitting 2 and the receiving part 96 of the brush cutter body 90. It is also possible to cut grass using only the rotating blade 8 clamped between the fitting 2 and the receiving part 96 of the brush cutter body 90.

[0084] 4. Modifications The embodiments described above are all just a few of the various embodiments of this disclosure. The embodiments described above can be modified in various ways, as long as they achieve the objectives of this disclosure.

[0085] The following describes modifications of the above embodiment. In the description of the modifications, components similar to those described in the above embodiment are denoted by the same reference numerals and their detailed descriptions are omitted. The various modifications listed below can be combined and applied as appropriate.

[0086] In the above embodiment, the number of through holes 24 is eight, but the number of through holes 24 is not limited to this and can be two or more. In the above embodiment, the multiple through holes 24 are located at equal intervals in the circumferential direction D2, but they may not be located at equal intervals.

[0087] In the above embodiment, the number of protrusions 26 is eight, but the number of protrusions 26 is not limited to this and can be two or more. In the above embodiment, the multiple protrusions 26 are positioned at equal intervals in the circumferential direction D2, but they may not be positioned at equal intervals.

[0088] In the above embodiment, there are eight recesses 28, but the number of recesses 28 is not limited to this and can be two or more. In the above embodiment, the multiple recesses 28 are positioned at equal intervals in the circumferential direction D2, but they may not be positioned at equal intervals.

[0089] In the above embodiment, all of the multiple protrusions 26 have flanges 264, but this is not essential; it is sufficient if at least one of the multiple protrusions 26 has a flange 264.

[0090] In the above embodiment, all flanges 264 of the multiple protrusions 26 are flared, but this is not essential; it is sufficient if the flange 264 of at least one of the multiple protrusions 26 is flared. For example, the flange 264 of at least one of the multiple protrusions 26 may have the shape shown in Figure 9. Even in this case, it has been confirmed in tests that the fitting 2 and the main body 3 are more firmly connected compared to the prior art.

[0091] In the above embodiment, the uneven portion 262 of the projection 26 is made up of a flange 264, but the uneven portion 262 on the outer surface of the projection 26 may be made up in a form that does not include a flange 264.

[0092] In the above embodiment, a flange 264 is provided at the tip of the projection 26, but the flange 264 may also be provided at a portion other than the tip of the projection 26.

[0093] In the above embodiment, a plurality of recesses 28 and a plurality of through holes 24 are alternately arranged in the circumferential direction D2 on the second surface 222 of the metal fitting 2, but the arrangement is not limited to this. Also, although a raised portion 29 is provided on the second surface 222 of the metal fitting 2, such a raised portion 29 may not be provided on the second surface 222.

[0094] In the above embodiment, it is assumed that the rotating body 1 is mainly used in contact with the ground E, but the invention is not limited to this, and it may also be assumed that the rotating body 1 is used while suspended above the ground E.

[0095] In the above embodiment, the multiple protrusions 26 of the metal fitting 2 are formed by striking them with punches 51 and 52. However, other methods can be used as long as multiple protrusions 26 can be formed on the metal fitting 2.

[0096] 5. Summary As described based on the above embodiments and modifications, the rotating body (1) of the first embodiment comprises a fitting (2) fixed to a drive rod (95) of the brush cutter body (90), and a resin body portion (3) molded integrally with the fitting (2). The fitting (2) includes a through hole (20) formed through it for inserting the drive rod (95), and an annular portion (22) positioned to surround the through hole (20). The annular portion (22) has a first surface (221) and a second surface (222) facing opposite directions in the axial direction (D1) of the through hole (20). The first surface (221) has a plurality of protrusions (26) formed at intervals in the circumferential direction (D2) of the annular portion (22), and each of the plurality of protrusions (26) is embedded in the body portion (3).

[0097] In this embodiment, the multiple protrusions (26) of the metal fitting (2) are embedded in the resin body (3), so a rotating body (1) is provided in which the metal fitting (2) and the body (3) are firmly connected.

[0098] In the second embodiment of the rotating body (1), in the first embodiment, the outer circumferential surface of at least one of the plurality of protrusions (26) includes an uneven portion (262).

[0099] In this embodiment, the projection (26) including the uneven portion (262) on its outer surface is embedded in the resin body (3), so that the metal fitting (2) and the body (3) are more firmly connected.

[0100] In the third embodiment of the rotating body (1), in the first embodiment, at least one of the plurality of projections (26) has a flange (264).

[0101] In this embodiment, the projection (26) having the flange (264) is embedded in the resin body (3), so that the fitting (2) and the body (3) are more firmly connected.

[0102] In the rotating body (1) of the fourth embodiment, the flange (264) has a flared shape, which widens towards the tip, as in the third embodiment.

[0103] In this embodiment, the projection (26) having a flared flange (264) is embedded in the resin body (3), so that the fitting (2) and the body (3) are more firmly connected.

[0104] In the fifth embodiment of the rotating body (1), in any one of the first to fourth embodiments, a plurality of recesses (28) are formed on the second surface (222) of the metal fitting (2) at intervals in the circumferential direction (D2). The plurality of recesses (28) are each located on the back side of the plurality of protrusions (26) in the annular portion (22).

[0105] According to this embodiment, the overall weight of the metal fitting (2) is reduced by providing multiple recesses (28) on the back side of each of the multiple protrusions (26).

[0106] In the sixth embodiment of the rotating body (1), in any one of the first to fifth embodiments, the annular portion (22) of the metal fitting (2) has a plurality of through holes (24) filled with resin (30) which constitutes part of the main body portion (3), and these holes are formed at intervals in the circumferential direction (D2).

[0107] In this embodiment, since resin (30) is filled into each of the multiple through holes (24) of the metal fitting (2), the metal fitting (2) and the main body (3) are more firmly bonded together.

[0108] In the rotating body (1) of the seventh embodiment, as in the fifth embodiment, the annular portion (22) of the fitting (2) has a plurality of through holes (24) filled with resin (30) which constitutes part of the main body (3), and these holes are formed at intervals in the circumferential direction (D2). On the second surface (222) of the fitting (2), a plurality of recesses (28) and a plurality of through holes (24) are alternately arranged in the circumferential direction (D2).

[0109] In this embodiment, the metal fitting (2) and the main body (3) are joined in a balanced manner in the circumferential direction (D2).

[0110] In the rotating body (1) of the eighth embodiment, as in the fifth embodiment, the second surface (222) has a raised portion (29) that is higher than the rest of the second surface (222) and surrounds the insertion hole (20). Multiple recesses (28) are open in the raised portion (29).

[0111] According to this embodiment, the rotating blade (8) can be applied to the raised portion (29) and stably held between the raised portion (29) and the brush cutter body (90).

[0112] In the rotating body (1) of the ninth embodiment, in any one of the first to eighth embodiments, the fitting (2) is configured to detachably clamp the rotating blade (8) between itself and the brush cutter body (90), and to rotate the rotating blade (8) together with the drive rod (95).

[0113] According to this embodiment, the rotating blade (8) is rotated integrally with the drive rod (95), allowing for stable grass cutting.

[0114] In the rotating body (1) of the tenth embodiment, in any one of the first to ninth embodiments, the main body (3) includes a recess (32) in which the tip of the drive rod (95) is housed, and a ground contact portion (35) formed to surround the recess (32).

[0115] According to this embodiment, the rotating blade (8) is rotated integrally with the drive rod (95), and the contact portion (35) of the rotating body (1) is brought into sliding contact with the ground (E), allowing for stable grass cutting work.

[0116] In the 11th embodiment of the rotating body (1), in any one of the first to tenth embodiments, the metal fitting (2) and the main body (3) are joined by insert molding.

[0117] According to this embodiment, the metal fitting (2) and the main body (3) are more firmly connected.

[0118] The brush cutter (9) of the twelfth embodiment comprises a rotating body (1) from any one of the first to eleventh embodiments and a brush cutter body (90).

[0119] According to this embodiment, a brush cutter (9) is provided, which includes a rotating body (1) to which a metal fitting (2) and a main body (3) are firmly connected.

[0120] A method for manufacturing a rotating body (1) according to the 13th embodiment is a method for manufacturing a rotating body (1) according to any one of the first to tenth embodiments, wherein the main body (3) connected to the metal fitting (2) is formed by insert molding.

[0121] According to this embodiment, a rotating body (1) is provided in which the metal fitting (2) and the main body (3) are more firmly connected.

[0122] A method for manufacturing a rotating body (1) according to the 14th embodiment is a method for manufacturing a rotating body (1) according to the 3rd or 4th embodiment, wherein a plurality of protrusions (26) are formed by striking a punch (51) against a second surface (222), and in the process, a flange (264) is formed by crushing the tip of at least one of the protrusions (26).

[0123] According to this embodiment, a rotating body (1) in which the metal fitting (2) and the main body (3) are firmly connected can be manufactured efficiently.

[0124] A method for manufacturing a rotating body (1) according to the 15th embodiment is a method for manufacturing a rotating body (1) according to the 4th embodiment, comprising the steps of forming a plurality of protrusions (26) by striking a punch (51) against a second surface (222), thereby crushing the tip of at least one protrusion (26), and forming a flange (264) into a flared shape by striking a punch (52) against the crushed tip of at least one protrusion (26).

[0125] According to this embodiment, a rotating body (1) in which the metal fitting (2) and the main body (3) are firmly connected can be manufactured efficiently.

Claims

1. A rotating body comprising: a fitting fixed to a drive rod having a brush cutter body; and a resin body molded integrally with the fitting, wherein the fitting includes a through hole formed for inserting the drive rod, and an annular portion positioned to surround the through hole, the annular portion having a first surface and a second surface facing opposite directions in the axial direction of the through hole, the first surface having a plurality of protrusions formed at intervals in the circumferential direction of the annular portion, and each of the plurality of protrusions being embedded in the body, 2. The rotating body according to claim 1, wherein the outer circumferential surface of at least one of the plurality of protrusions includes an uneven portion.

3. The rotating body according to claim 1, wherein at least one of the plurality of protrusions has a flange.

4. The rotating body according to claim 3, wherein the flange has a flared shape that widens towards the tip.

5. The rotating body according to any one of claims 1 to 4, wherein the second surface of the metal fitting has a plurality of recesses formed at intervals in the circumferential direction, and the plurality of recesses are respectively located on the back side of the plurality of protrusions in the annular portion.

6. The rotating body according to any one of claims 1 to 5, wherein the annular portion of the metal fitting has a plurality of through holes filled with resin that constitutes a part of the main body, which are formed at intervals in the circumferential direction.

7. The rotating body according to claim 5, wherein the annular portion of the metal fitting has a plurality of through holes filled with resin that constitutes a part of the main body, which are formed at intervals in the circumferential direction, and the plurality of recesses and the plurality of through holes are alternately arranged in the circumferential direction on the second surface of the metal fitting.

8. The rotating body according to claim 5, wherein the second surface has a raised portion that is higher than the rest of the second surface, surrounding the insertion hole, and the plurality of recesses open in the raised portion.

9. The rotating body according to any one of claims 1 to 8, wherein the fitting is configured to detachably clamp the rotating blade between itself and the brush cutter body, and to rotate the rotating blade integrally with the drive rod.

10. The rotating body according to any one of claims 1 to 9, wherein the main body portion includes a recess for housing the tip of the drive rod and a ground contact portion formed to surround the recess.

11. The rotating body according to any one of claims 1 to 10, wherein the metal fitting and the main body are joined by insert molding.

12. A brush cutter comprising a rotating body according to any one of claims 1 to 11, and the brush cutter body.

13. A method for manufacturing a rotating body according to any one of claims 1 to 10, wherein the main body portion coupled to the fitting is formed by insert molding.

14. A method for manufacturing a rotating body according to claim 3 or 4, comprising forming the plurality of protrusions by punching the second surface, and thereby forming the flange by crushing the tip of at least one of the protrusions.

15. A method for manufacturing a rotating body according to claim 4, comprising the steps of: forming the plurality of protrusions by striking a punch against the second surface, thereby crushing the tip of at least one of the protrusions; and forming the flange into a flared shape by striking the crushed tip of at least one of the protrusions with a punch.

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