JP2016067297A - Portable work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vibration transmitted to a worker, in a portable work machine in which a thin shaft is used.SOLUTION: A crank shaft of an engine is connected via a centrifugal clutch to a drive shaft arranged on a same shaft inside of a thin shaft 11. Accordingly, the drive shaft is driven and rotated about a shaft center thereof, and rotational motion thereof is transmitted to a gear case 12 and appropriately decelerated to be transmitted to a rotary shaft to which a reaping blade is fixed. Around a center of the shaft 11 in a longitudinal direction, there is provided a handle 14 capable of being gripped by a worker. In a reaping machine 1, a connection part in which the shaft 11 and the drive shaft can be separated from each other is provided at two points of a cross section A-A and a cross section B-B in FIG. 1. The connection part is constituted by combining a first unit and a second unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a portable working machine having a working member that is driven by rotating a driving shaft in an elongated shaft at one end of the shaft.

  In a brush cutter that is a type of portable work machine, a cutting blade (working member) is provided on the front end (one end) side of an elongated shaft (operating rod), and the cutting blade rotates to perform cutting work such as plants. Done. As a power source of such a brush cutter, a small engine or motor is used. A brush cutter in which an engine is used as a power source can obtain a high output as compared with the case where a motor is used and has a long continuous use time. Therefore, the brush cutter is particularly preferably used outdoors.

  In this case, since the power unit including the engine is heavy, the power unit is provided on the rear end (other end) side of the shaft opposite to the cutting blade. A brush cutter having such a configuration is described in Patent Document 1, for example. FIG. 8 is a side view showing the configuration of such a brush cutter 500. Here, a gear case 502 is provided on the front end side of an elongated shaft (operation rod) 501, and a cutting blade (working member) 503 is attached to a rotation shaft (not shown) provided in the gear case 502. The rotation shaft is driven by a drive shaft (not shown) provided coaxially in the shaft 501. On the other hand, the drive shaft is driven by the engine in the power unit 504. Further, a handle 505 is provided in the vicinity of the center of the shaft 501 in the front-rear direction so that the operator can easily carry the brush cutter 500 in such a form. The handle 505 is equipped with a cutting blade 503 or a throttle lever (not shown) for controlling the engine speed. For this reason, the operator can operate the throttle lever while grasping the handle 505 to bring the cutting blade 503 into contact with the plant or the like to be cut. At this time, in order to perform the mowing work smoothly, the length of the shaft 501 is set to about 1.5 m, for example.

JP 2013-146204 A

  When such a long shaft 501 is used, the drive shaft inside thereof is also lengthened accordingly, and when there is eccentricity (runout) during manufacture of the drive shaft, vibration during operation is large. Become. In addition, particularly when the engine is used as a power source during operation, vibration generated by the engine during operation increases, and this vibration is transmitted through the drive shaft. For this reason, in the above configuration, vibrations are transmitted to the worker violently through the handle 505 and the like during the work. If the drive shaft is made of an elastic body, such vibration is reduced, but in this case, it is difficult to ensure the durability of the drive shaft.

  That is, in a portable work machine using an elongated shaft, it has been desired to reduce vibration transmitted to the worker.

  The present invention has been made in view of such problems, and an object thereof is to provide an invention that solves the above problems.

In order to solve the above problems, the present invention has the following configurations.
A portable work machine according to the present invention is a portable work machine including a drive shaft that extends from one end to the other end and rotates around an axis along a longitudinal direction to transmit power from the other end to the one end. In the drive shaft, the first unit provided on one side of the one end and the other end in the length direction, and the other end of the one end and the other end in the length direction. A connecting portion is provided that is separable from the provided second unit, and an elastic body is provided in the connecting portion, and the power is transmitted through the elastic body. It is characterized by.
The portable work machine according to the present invention is characterized in that a plurality of the first connecting portions are provided in the longitudinal direction on the drive shaft.
In the portable work machine of the present invention, in the drive shaft, the first unit in the plurality of connecting portions and the second unit in the plurality of connecting portions are respectively provided on the same side in the longitudinal direction of the drive shaft. It is characterized by that.
In the portable work machine according to the present invention, a region between the two connecting portions in the longitudinal direction of the drive shaft is separable from other regions in the longitudinal direction of the drive shaft.
The portable work machine according to the present invention is characterized in that a plurality of types having different lengths are provided as a region between the two connecting portions in the longitudinal direction of the drive shaft.
In the portable work machine according to the present invention, the first unit includes four dampers each having a central axis parallel to the drive shaft and formed of an elastic body. Each of the central axes is rectangular when viewed from the axis. The second unit has a rectangular section that is inserted from the axial direction into the center of the structure in which the four dampers viewed from the axial direction are arranged. And the four dampers are in contact with the damper fitting portions so that power is transmitted between the first unit and the second unit. .
The portable work machine according to the present invention is characterized in that the drive shaft is coaxially provided inside a cylindrical shaft, and the shaft can be divided at a position corresponding to the connecting portion.
In the portable work machine of the present invention, a handle to be held by an operator is fixed to the shaft.
The portable work machine according to the present invention includes a power source having a built-in power source and provided on the other end side of the handle in the shaft, and driven by the power source via the drive shaft from the handle in the shaft. And a working member provided on the one end side.
The portable work machine according to the present invention is characterized in that the two connecting portions are provided on the one end side with respect to the connecting portion of the handle and the shaft in the longitudinal direction of the shaft.
The portable work machine according to the present invention is characterized in that the connecting portions are provided on both sides of a connecting portion between the handle and the shaft in the longitudinal direction of the shaft.
The portable working machine of the present invention is a brush cutter in which the working member is a cutting blade.

  Since this invention is comprised as mentioned above, in the portable working machine using the elongate shaft, the vibration transmitted to an operator can be reduced.

It is a side view which shows the structure of the brush cutter used as embodiment of this invention. It is an assembly drawing of the connection part used in the brush cutter which becomes embodiment of this invention. It is sectional drawing which shows the structure of the 1st unit of the connection part in the brush cutter which becomes embodiment of this invention. It is sectional drawing which shows a structure at the time of the connection part in the brush cutter used as embodiment of this invention being connected. It is sectional drawing which shows the structure containing the shaft of the connection part in the brush cutter which becomes embodiment of this invention. It is sectional drawing which shows the structure (with a knob for connection) containing the shaft of the connection part in the brush cutter which becomes embodiment of this invention. It is a side view which shows the structure at the time of using a long shaft component in the brush cutter used as embodiment of this invention. It is a side view which shows the whole structure of an example of the conventional brush cutter.

  A configuration of a brush cutter (portable work machine) according to an embodiment of the present invention will be described. FIG. 1 is a side view showing the configuration of the brush cutter 1. In FIG. 1, the left side is the front of the worker during work, and the right side is the rear. Also in this brush cutter 1, a gear case 12 to which a cutting blade (working member) is attached is provided on the front end (one end) side of a shaft (operating rod) 11 that is elongated in the front-rear direction, and the power case is provided on the rear end (other end) side. A power unit 13 having a built-in engine is provided. The cutting blade is detachable from the gear case 12, and FIG. 1 shows a state where the cutting blade is not attached. The crankshaft of the engine is connected to a drive shaft (not shown in FIG. 1) provided coaxially inside the elongated shaft 11 via a centrifugal clutch. As a result, the drive shaft is rotationally driven around its axis, and this rotational motion is transmitted to the gear case 12, moderately decelerated, and transmitted to the rotational shaft to which the cutting blade is fixed. A cooling fan is also fixed to the crankshaft, and cooling air is always generated when the crankshaft rotates, thereby cooling the engine, the muffler, and the like. A handle 14 that can be gripped by an operator is provided near the center of the shaft 11 in the front-rear direction. The above points are the same as the brush cutter 500 described above.

  However, in this brush cutter 1, the connection part which made the shaft 11 and the drive shaft separable is provided in two places of the cross section AA and the cross section BB in FIG. The connecting portion is configured by combining the first unit and the second unit. FIG. 2 is an assembly diagram illustrating the configuration of the first unit 20 and the second unit 30 that constitute the connecting portion. In the drive shaft, the first unit 20 is fixed to the power unit 13 side, and the second unit 30 is fixed to the gear case 12 side. The first unit 20 and the second unit 30 can be divided. FIG. 2A shows an assembled view of each of the first unit 20 and the second unit 30, and FIG. 2B shows a state where the first unit 20 and the second unit 30 are assembled. Has been.

  The first unit 20 is fixed to a power unit side drive shaft 15A that is a portion of the drive shaft on the power unit 13 side. For this reason, as shown in FIG. 2A, the first unit base 21 made of a cylindrical metal is fixed to the end of the power unit side drive shaft 15A. A substantially cylindrical damper cover 23 is fixed to the inner surface of the first unit base 21 in a state in which the damper 22 is accommodated inside the first unit base 21. The unit is fixed to the unit base 21 and the power unit side drive shaft 15A.

  The damper portion 22 is fixed to the main surface of one of the rubber damper fixing portions 22A made of a metal having a disc shape that fits inside the first unit base 21 and one of them (the gear case side drive shaft 15B side). It is composed of four cylindrical rubber dampers 22B. The rubber damper 22B is composed of an elastic body (hard rubber or the like), the center axis thereof is parallel to the axis of the drive shaft, and the center axis of each rubber damper 22B forms a square apex when viewed from the axial direction. Arranged.

  The damper cover 23 is configured to be fixed to the first unit base 21 in a state in which a configuration (damper portion 22) in which four rubber dampers 22B are arranged therein is accommodated therein. For this reason, on the power unit side drive shaft 15 </ b> A side, a fitting portion 23 </ b> A having a cylindrical outer surface that fits on the inner surface of the first unit base 21 is provided. In addition, a damper connection hole 23B having a substantially rectangular shape is provided to accommodate a configuration in which four rubber dampers 22B are arranged from the surface on the gear case side drive shaft 15B side to the surface on the power unit side drive shaft 15A side of the damper cover 23. It has been. Since the damper cover 23 is used to fix the damper portion 22 to the first unit base portion 21, the damper cover 23 is made of a resin material, metal, or the like that does not elastically deform and has a fixed shape. The damper cover 23 and the damper portion 22 are fixed to the first unit base portion 22 by press-fitting the fitting portion 23 </ b> A into the inner surface of the first unit base portion 21. As shown in FIG. 2B, the assembled part is covered with a damper cover 23 after the assembly.

  On the other hand, the second unit 30 is fixed to a gear case side drive shaft 15B which is a portion of the metal drive shaft on the gear case 12 side. Here, a metal (inelastic body) damper fitting portion 31 extending coaxially with the drive shaft and having a rectangular cross section is the second unit 30. The damper fitting portion 31 is sized so that it can be inserted into the center of the configuration in which the four rubber dampers 22B in the damper portion 22 are arranged.

  FIG. 3A is a cross-sectional view along the central axis of the first unit 20, and FIG. 3B is a cross-sectional view in the CC direction thereof. As shown in FIG. 3B, the four rubber dampers 22B are respectively inscribed in the inner surfaces of the damper connection holes 23B on the four vertex sides of the substantially rectangular shape of the damper connection holes 23B. Therefore, the four rubber dampers 22B (damper part 22), the damper cover 23, and the first unit base part 21 rotate together with the power part side drive shaft 15A.

  FIG. 4A is a cross-sectional view along the central axis of the structure when the first unit 20 and the second unit 30 are combined, and corresponds to FIG. FIG. 4B is a cross-sectional view in the DD direction in this state, and corresponds to FIG. 3B and is a cross-sectional structure in the shaft 11 in the AA cross section and the BB cross section in FIG. Corresponding to As shown in FIG. 3B, when viewed from the axial direction of the drive shaft, the rectangular damper fitting portion 31 is inserted into the center where the four rubber dampers 22B are arranged. At this time, the damper fitting portion 31 is inserted into the damper connecting hole 23B in such a form that the apex comes between the two adjacent rubber dampers 22B, and each rubber damper 22B is elastically deformed and compressed in a compressed state. The joint part 31 can be supported stably. That is, in this state, the first unit 20 and the second unit 30 are coupled. Further, by separating the first unit 20 and the second unit 30 along the axial direction, they can be easily separated.

  When the first unit 20 and the second unit 30 are combined, power is transmitted from the first unit 20 (power unit side drive shaft 15A) side to the second unit 30 (gear case side drive shaft 15B). . The power transmission at this time is performed by contacting the four rubber dampers 22B made of an elastic body and the damper fitting portion 31 made of an inelastic body. At this time, since the four rubber dampers 22B are elastically deformed, this can absorb vibration. For this reason, the vibration transmitted to the worker is reduced.

  The first unit 20 and the second unit 30 are components provided on the drive shaft. As described above, the drive shaft is actually provided inside the shaft 11, so that the shaft 11 can be divided in accordance with the drive shaft. It is said. FIG. 5 is a diagram illustrating the configuration of the connecting portion including the shaft 11 and corresponds to FIG. 4. FIG.5 (b) is sectional drawing of the EE direction in Fig.5 (a).

  5A, the shaft 11 is divided into a shaft 11A on the side where the first unit 20 is provided and a shaft 11B on the side where the second unit 30 is provided. The shaft 11A and the shaft 11B are divided. Are equal in both inner diameter and outer shape. Here, the first unit base 21 in the first unit 20 is not in contact with the cylindrical shafts 11A and 11B, and the power unit side drive shaft 15A and the gear case side drive shaft 15B are actually the shaft 11A. , 11B are supported by a plurality of bushes (metal bearings) (not shown). A shaft connecting portion 11X having an inner diameter larger than that of the shaft 11A (11B) is provided from the location where the first unit base 21 exists to the second unit 30 side. The inner diameter of the shaft connecting portion 11X is the shaft. It is made substantially equal to the outer diameter of 11B (11A).

  For this reason, the 1st unit 20 and the 2nd unit 30 can be connected as mentioned above, and the shaft connection part 11X by the side of the 1st unit 20 can be fitted to the shaft 11B by the side of the 2nd unit. That is, as shown in FIG. 5, the shaft 11A, the first unit 20, and the component combined with the power unit side drive shaft 15A, and the component combined with the shaft 11B, the second unit 30, and the gear case side drive shaft 15B are as shown in FIG. Can be easily connected.

  In the structure of FIG. 1, a coupling knob 40 is further provided to firmly fix the shafts 11A and 11B in the structure of FIG. 5 and prevent the shafts 11A and 11B from rotating during operation. ing. FIG. 6 is a sectional view showing this structure and corresponds to FIG. In this structure, in a portion where the shaft connecting portion 11X and the shaft 11B are fitted, a fixing through hole 11Y that penetrates the shaft connecting portion 11X and the shaft 11B is formed when they are fitted. The inner surface of the fixing through hole 11Y is threaded. A fixing screw 41 is attached to the lower side of the connecting knob 40 in FIG. 6, and the fixing screw 41 is attached to the fixing through hole 11Y in a state where the shaft connecting portion 11X and the shaft 11B are fitted. be able to.

  Therefore, when connecting the first unit 20 and the shaft 11A to the second unit 30 and the shaft 11B, the operator turns the connecting knob 40 and attaches the fixing screw 41 to the fixing through hole 11Y. Thus, it is possible to firmly fix the space between them. Even at this time, as described above, the transmission of power is not changed between the rubber damper 22B and the damper fitting portion 31, so that the vibration transmitted to the operator is reduced. Further, the first unit 20 and the shaft 11A and the second unit 30 and the shaft 11B are easily separated after the connecting knob 40 is turned in the reverse direction and the fixing screw 41 is removed from the fixing through hole 11Y. Can do.

  Moreover, in the structure of FIG. 1, the connection part of said structure is provided in two places of AA and BB. At this time, the direction of the connecting portion in each of AA and BB in FIG. 1 is the same as the orientation shown in FIG. 6, and in either case, the first unit 20 is on the right side (power unit 13 side). The second unit 30 is connected from the left side (gear case 12 side). For this reason, in the brush cutter 1, the drive shaft 15 and the shaft 11 between AA and BB in FIG. 1 can be removed as an integrated component (shaft component 111). The shaft component 111 is provided with a first unit 20 on the left side and a second unit 30 on the right side. A plurality of types of shaft parts 111 having different lengths can be set, and the total length of the shaft 11 can be set by selecting them and using them in the brush cutter 1. FIG. 7 shows a configuration in which the entire length of the shaft 11 is made longer than in the case of FIG. 1 by using a long shaft component 111.

  Thus, in the case of using a plurality of shaft parts 111 that can be divided by the connecting portion (the first unit 20, the second unit 30), as in this example, each shaft part 111 has the first unit 20 on one side, If the second unit 30 is unified on the other side and the shaft connecting portion 11X is provided on the one side, a plurality of shaft components 111 can be connected. Thereby, the freedom degree of the length setting of the shaft 11 further increases. At this time, the vibration is reduced at each connecting portion, so that the effect of reducing the vibration is particularly great. In particular, when the entire length of the drive shaft 15 is long, the effect of the shake of the drive shaft 15 becomes large and vibration is likely to occur, so this effect is remarkable. Further, if the first unit 20 and the second unit 30 in any of the shaft components 111 are damaged, only this shaft component 111 needs to be replaced. Alternatively, the brush cutter 1 can be transported in a disassembled and shortened state.

  Further, when the long drive shaft 15 (shaft 11) is configured by a combination of the short shaft components 111 as described above, the drive shaft 15 used in the single shaft component 111 is shortened, and thus the eccentricity at the time of manufacture is achieved. The absolute value of can be reduced. From this point of view, vibration can be reduced.

  Further, if the rubber damper 22B at the connecting portion is damaged, power is not transmitted to the gear case 12 side, and the cutting blade is stopped, so that the safety of the workplace is also ensured. Further, for example, during an overload operation in which rotation of the cutting blade is hindered due to a heavy load on the cutting blade, a large load is applied to the centrifugal clutch, the cylinder, and the like, which may cause damage or galling. In this case, the clutch housing, crankshaft, cylinder, and piston need to be repaired or replaced. In such a case, if the structure and strength of the rubber damper 22B are set so that the rubber damper 22B is damaged before the centrifugal clutch or the like, the centrifugal clutch or the like can be prevented from being damaged. In this case, since the replacement work of the shaft part 111 is easier than the replacement work of the centrifugal clutch or the like, it is possible to easily cope with the case where the rubber damper 22B is damaged. Further, the rubber damper 22B is less expensive than a centrifugal clutch or the like, and replacement of only the rubber damper 22B can be performed at a low cost.

  1 and 7, the two connecting portions are both provided in front of the handle 14 (in front of the connecting portion between the handle 14 and the shaft 11). However, it is also possible to provide a connecting portion in front of and behind the connecting portion of the handle 14 and the shaft 11, respectively. In this case, the handle 14 can be exchanged. For example, there are two types of handles used in a brush cutter: a bike handle as shown in FIGS. 1 and 7 and an annular loop handle. These handles can be selected according to the preference of the worker, or these handles having an appropriate size can be selected and used according to the physique of the worker. That is, the handle can be easily replaced.

  In the above example, the first unit 20 and the second unit 30 having the structure shown in FIG. 2 and the like are used. However, the structure is such that power is transmitted by the contact between the second unit and a member made of an elastic body fixed to the first unit, and the first unit and the second unit can be easily connected and separated. Obviously, it can be used similarly. For example, since the rotation direction of the drive shaft is generally determined during operation, the damper cover 23 can be screwed to the first unit base 21 in such a direction that the screw does not loosen during this rotation. Further, the rubber damper can be fixed to the power unit side drive shaft side in any manner.

  In the above example, the first unit 20 (rubber damper 22B) is fixed to the power unit side drive shaft 15A side, and the damper fitting portion 31 (second unit 30) that contacts the rubber damper 22B is on the gear case side drive shaft 15B side. Fixed to. However, it is obvious that the same effect can be obtained by fixing the first unit to the gear case side drive shaft and fixing the second unit to the power unit side drive shaft.

  Furthermore, although the above example is a brush cutter, it is clear that the same configuration is effective if it is a portable work machine in which the work member using the elongated shaft and the drive shaft is provided on one end side. is there. Examples of such portable work machines include a pole hedge trimmer and a pole saw. Furthermore, since it becomes easy to replace the entire part including the gear case and the like ahead of the connecting part by using the connecting part, for example, the front part of the brush cutter 1 is replaced with the power unit 13 and the drive shaft. 15 can be replaced with a part for a hedge trimmer and a part for a pole saw, which are driven in the same manner. In this case, the brush cutter 1 can be used as a hedge trimmer or a pole saw. In these cases, the optimum length of the shaft 11 varies, but at this time, the length can be optimized as described above. At this time, the working member is not limited to one that performs a rotational motion, and the same applies to, for example, a reciprocating motion member.

1,500 Brush cutter (portable work machine)
11, 11A, 11B, 501 Shaft (operating rod)
11X Shaft connecting portion 11Y Fixing through hole 12, 502 Gear case 13, 504 Power portion 14, 505 Handle 15 Drive shaft 15A Power portion side drive shaft (drive shaft)
15B Gear case side drive shaft (drive shaft)
20 First unit 21 First unit base portion 22 Damper portion 22A Rubber damper fixing portion 22B Rubber damper 23 Damper cover 23A Fitting portion 23B Damper connecting hole 30 Second unit 31 Damper fitting portion 40 Connecting knob 41 Fixing screw 111 Shaft component 503 Cutting blade (working member)

Claims (12)

A portable work machine comprising a drive shaft that extends from one end to the other end and rotates around an axis along the longitudinal direction to transmit power from the other end to the one end,
In the drive shaft, a first unit provided on one side of the one end and the other end in the length direction, and a first unit provided on the other side of the one end and the other end in the length direction. The second unit is provided with a connecting portion that can be separated and connected, and the connecting portion is provided with an elastic body, and the power is transmitted through the elastic body. A portable work machine.   The portable work machine according to claim 1, wherein a plurality of the connecting portions are provided in the longitudinal direction on the drive shaft.   The said drive shaft WHEREIN: The said 1st unit in the said some connection part and the said 2nd unit in the said some connection part were each provided in the same side in the longitudinal direction of the said drive shaft, The said drive unit is characterized by the above-mentioned. The portable work machine according to 2.   The portable work machine according to claim 3, wherein a region between the two connecting portions in the longitudinal direction of the drive shaft is separable from other regions in the longitudinal direction of the drive shaft.   5. The portable work machine according to claim 4, wherein a plurality of types having different lengths are provided as regions between the two connecting portions in the longitudinal direction of the drive shaft. The first unit has a configuration in which four dampers, each having a central axis parallel to the drive shaft and made of an elastic body, are fixed so that each central axis has a rectangular shape when viewed from the axis. Comprising
The second unit includes a damper fitting portion having a rectangular cross section inserted from the axial direction at the center of a structure in which the four dampers viewed from the axial direction are arranged;
The motive power is transmitted between the first unit and the second unit when the four dampers and the damper fitting portion are in contact with each other. The portable work machine of Claim 1.   The drive shaft is coaxially provided inside a cylindrical shaft, and the shaft can be divided at a position corresponding to the connecting portion. The portable work machine as described in the item.   The portable work machine according to claim 7, wherein a handle to be gripped by an operator is fixed to the shaft. A power unit having a built-in power source and fixed to the shaft on the other end side than the handle;
A working member driven by the power source via the drive shaft and attached to the shaft on the one end side with respect to the handle;
The portable working machine according to claim 8, comprising:   The portable work machine according to claim 9, wherein the two connecting portions are provided on the one end side of a connecting portion between the handle and the shaft in a longitudinal direction of the shaft.   The portable work machine according to claim 9, wherein the connecting portions are provided on both sides of a connection portion between the handle and the shaft in a longitudinal direction of the shaft.   The portable working machine according to any one of claims 8 to 11, wherein the working member is a brush cutter having a cutting blade.

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