Work machine

Abstract

The present invention improves workability of a work machine. A work machine 10 comprises: a motor unit 11 which includes an electric motor; a battery pack 13 which supplies electric power to the electric motor; an attachment unit 16 to which the battery pack 13 is attached; a drive unit 20 which is connected to the motor unit 11; a cover 15 which covers the drive unit 20; an output shaft 30 which is supported by the drive unit 20; a tip-end tool 52 which is attached to a tip end of the output shaft 30; and a housing 14 which houses the motor unit 11. In the work machine 10, the drive unit 20 and the cover 15 are coupled to each other via a U-shaped elastic member 22, and the motor unit 11 and the housing 14 are connected to each other without an elastic body therebetween.

Description

Work equipment

[0001] The present invention relates to a work machine.

[0002] One example of a work machine is known, which includes an electric motor unit, a drive unit connected to the motor unit, a housing that accommodates the motor unit, and a tool tip that operates using the driving force of the motor unit.

[0003] As an example of such a work machine, Patent Document 1 discloses a work machine that performs machining by oscillating (reciprocating) a tool tip attached to an output shaft of a drive unit from side to side.

[0004] Japanese Patent Application Laid-Open No. 2015-127075

[0005] In the work machine described in Patent Document 1, the operator holds part of the housing to perform machining, but vibrations are transmitted from the drive unit to the housing, increasing the vibrations of the housing, which in turn increases the vibrations transmitted to the operator, leading to a decrease in workability.

[0006] Therefore, it has been desired to reduce the vibration transmitted to the operator during machining and improve the workability of the work machine.

[0007] An object of the present invention is to provide a work machine with improved workability.

[0008] The work machine of the present invention has a motor unit, a drive unit connected to the motor unit, an output shaft supported by the drive unit, and a housing that accommodates the motor unit, and the drive unit and the housing are connected via an elastic body, and the motor unit and the housing are connected without the elastic body, or the drive unit and the housing are connected without the elastic body, and the motor unit and the housing are connected via the elastic body.

[0009] According to the present invention, the workability of a work machine can be improved.

[0010] 1. A side cross-sectional view showing the structure of a working machine according to a first embodiment of the present invention. 2. A cross-sectional view showing the arrangement of elastic bodies in the working machine of FIG. 1. 3. A perspective view showing the structure of an elastic body assembled to the working machine of FIG. 1. 4. A partial perspective view showing the structure of a drive unit into which the elastic body of FIG. 3 is fitted. 5. A partial perspective view showing a state in which the elastic body is fitted in the drive unit of FIG. 4. 6. A cross-sectional perspective view showing the structure of FIG. 5, cut in the horizontal direction. 7. A cross-sectional view showing the structure of a working machine according to a first modified embodiment of the present invention. 8. A cross-sectional view showing the arrangement of elastic bodies in the working machine of FIG. 7. 9. A cross-sectional view taken along the line A-A in FIG. 10. 11. A cross-sectional perspective view showing the rear extension portion of FIG. 10, cut in the vertical direction. 12. A cross-sectional perspective view showing the rear extension portion of FIG. 11, cut in the horizontal direction. 13. A cross-sectional perspective view showing the arrangement of elastic bodies in a working machine according to a second modified embodiment of the present invention. 14. A perspective view showing the structure of a rear extension portion of the working machine of FIG. 13. 15. A cross-sectional perspective view showing the rear extension portion of FIG. 14, cut in the vertical direction. 16. A cross-sectional perspective view showing the rear extension portion of FIG. 14, cut in the horizontal direction. Fig. 17 is a cross-sectional view showing the arrangement of elastic bodies in a work machine according to a third modified example of an embodiment of the present invention. Fig. 18 is a perspective view showing the structure of a rear extension portion of the work machine of Fig. 17. Fig. 19 is a cross-sectional perspective view showing the rear extension portion of Fig. 18 cut in the vertical direction. Fig. 19 is a cross-sectional perspective view showing the rear extension portion of Fig. 18 cut in the horizontal direction.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings used to explain each embodiment, the same elements are designated by the same reference numerals. In the present embodiment, an electric working machine in which a tool tip is driven by an electric motor will be described as an example of the working machine.

[0012] The work machine 10 shown in Figure 1, also known as a multi-tool, has a device body 12 that houses a motor unit 11 (electric motor 11a and motor case 11b) and a battery pack 13 that supplies power to the electric motor 11a. The battery pack 13 is detachable from the device body 12. The work machine 10 is a cordless type, meaning that the device body 12 does not have a power cord for connecting to a commercial power outlet. In addition, in the cross-sectional view, the positional relationships of components are clearly indicated by hatching.

[0013] The device main body 12 includes a housing (outer housing) 14 through which the first axis A1 passes (extending in the direction of the first axis A1) and a cover (housing, outer housing) 15 disposed at one end (front end) of the housing 14 in a direction along the first axis A1. The housing 14 and the cover 15 are integral (a single, continuous member), and the cover 15 covers a drive unit (head unit) 20 connected to the motor unit 11. In other words, the housing portion located forward of the motor unit 11 is the cover 15. The motor unit 11 and the drive unit 20 are integrally connected by fastening elements such as screws. The housing 14 is cylindrical and includes an attachment portion 16. The attachment portion 16 is located on the opposite side of the end to which the cover 15 is attached in the direction along the first axis A1. The battery pack 13 is attached to and detached from the attachment portion 16. The housing 14 is provided with a grip portion 14a having a diameter smaller than that of the portion accommodating the electric motor 11a. An operator can grasp the grip portion 14a to perform work. The housing 14 and cover 15 are integral (a single, continuous member) but can be separated in the left-right direction. The housing 14 and cover 15 are made of resin. Although not shown, elastic portions (elastomers) are integrally molded on the outer surfaces of the housing 14 and cover 15 (mainly around the grip portion 14a) to improve grip strength. The technique of integrally molding elastic portions (elastomers) into a resin housing is well known. The electric motor 11a, which serves as the power source, is housed in a motor case 11b and is installed within the housing 14. The electric motor 11a has a motor shaft 17. A main switch 18 is installed within the housing 14, and a slide switch 19, operated by the operator, is installed on the outer wall of the housing 14 (in front of the grip portion 14a). The slide switch 19 is movable along the housing 14 and can turn the main switch 18 on and off by moving it. Furthermore, a controller 21 is installed within the housing 14. The controller 21 is a known microcomputer equipped with a drive circuit, a calculation unit, a storage unit, an input port, an output port, and the like.

[0014] A synthetic resin holder 29 is provided inside the housing 14 (cover 15). The front end of the holder 29 is connected to a rear end portion 11d of a drive unit case, which will be described later, and the motor shaft 17 is rotatably supported by the holder 29 via a bearing 11c.

[0015] The cover 15 also houses a drive unit 20. The drive unit 20 has a drive unit case 20a, which supports (houses) an output shaft 30. The drive unit case 20a is made of metal. The output shaft 30 is cylindrical, and is supported by the drive unit case 20a so as not to move in the direction along the second axis B1.

[0016] A power transmission mechanism 35 is also provided within the drive unit case 20a. The power transmission mechanism 35 converts the rotational force of the motor shaft 17 into a force that causes the output shaft 30 to reciprocate within a predetermined angular range. The power transmission mechanism 35 includes a spindle 36 that rotates integrally with the motor shaft 17. The spindle 36 is provided concentrically with the motor shaft 17. The center line of the spindle 36 is coaxial with the first axis A1 of the motor shaft 17, and an eccentric shaft 39 is provided on the spindle 36. The center line of the eccentric shaft 39 is positioned eccentrically from the first axis A1. An inner ring of a ball bearing 40 is attached to the outer peripheral surface of the eccentric shaft 39.

[0017] A swing arm 41 is provided to connect the outer ring of the ball bearing 40 and the output shaft 30. The swing arm 41 is fixed to the output shaft 30. The swing arm 41 is formed in a U-shape with a pair of arm portions extending parallel to the motor shaft 17. The pair of arm portions are arranged at a distance equal to the outer diameter of the outer ring of the ball bearing 40. The pair of arm portions are in contact with the outer ring of the ball bearing 40. In other words, the outer ring of the ball bearing 40 is sandwiched between the pair of arm portions.

[0018] The drive unit 20 also has a first shaft 42 that is provided inside the drive unit case 20a and is movable in a direction along the second axis B1. The drive unit 20 also has a second shaft 46 that is disposed inside the output shaft 30. One end of the second shaft 46 in the direction along the second axis B1 is fixed to the first shaft 42. Therefore, the first shaft 42 and the second shaft 46 are movable together in the direction along the second axis B1. In other words, the first shaft 42 and the second shaft 46 are movable in the longitudinal direction.

[0019] A tool fixing member 55 is provided at the tip of the second shaft 46, and the tool bit 52 is attached to the output shaft 30 by clamping the tool bit 52 between the tool fixing member 55 and the output shaft 30. The attachment and detachment structure of the tool bit 52 in this embodiment is similar to that described in the prior art documents, and therefore a detailed description thereof will be omitted.

[0020] When the worker operates the slide switch 19 to turn on the main switch 18 while the battery pack 13 is attached to the mounting portion 16 of the work machine 10, power from the battery pack 13 is supplied to the electric motor 11a via the controller 21, causing the motor shaft 17 of the electric motor 11a to rotate. On the other hand, when the slide switch 19 is operated to turn off the main switch 18, power from the battery pack 13 is no longer supplied to the electric motor 11a, causing the motor shaft 17 of the electric motor 11a to stop rotating.

[0021] In the work machine 10, when power is supplied to the electric motor 11a and the motor shaft 17 rotates in one direction, the motor shaft 17 and spindle 36 rotate together. As the spindle 36 rotates, the eccentric shaft 39 and the ball bearing 40 revolve around the first axis A1. As the ball bearing 40 revolves around the first axis A1, the swing arm 41 reciprocates (swings) within a predetermined angle range, with the output shaft 30 as the fulcrum. As a result, the output shaft 30 alternately rotates forward and backward within a predetermined angle range around the second axis B1. In this way, the rotational force of the electric motor 11a is converted into rotational force (vibration force) of the output shaft 30.

[0022] When the output shaft 30 rotates forward and backward within a predetermined angle range, the tool bit 52 also rotates within a predetermined angle range around the second axis B1. When the tool bit 52 is pressed against an object, the object can be processed, for example, cut or polished.

[0023] Next, vibration countermeasures for the work machine 10 of this embodiment will be described. In the work machine 10, the motor unit 11 and the drive unit 20 are integrally connected by a fixing element 50 such as a screw. That is, the motor unit 11 and the drive unit 20, which are configured as separate components, are integrated and supported by the outer housing (housing 14, cover 15) as an inner unit (drive unit). Therefore, in the work machine 10, the motor unit 11 and the drive unit 20 vibrate together during operation. Therefore, it is necessary to consider reducing vibration transmitted to the operator. With the configuration of this embodiment, lateral vibration occurs due to the reciprocating motion of the output shaft 30 and the swing arm 41 in the lateral direction. Furthermore, because the swing arm 41 vibrates in the lateral direction about the second axis B1, forward-backward motion also occurs (especially at the rear end), and this motion also generates forward-backward vibration. Vibration in the up-down direction is smaller than that in the lateral and longitudinal directions. When considering vibration, it is conceivable to place an elastic body (damper) between the vibration source and the operator's hand (grip 14a). However, because the vibration source can move relative to the grip 14a (housing 14), it is important to consider how to restrict this relative movement while damping the vibration. Furthermore, the amplitude of the vibration source may vary depending on the location. In the work machine 10 of this embodiment, as shown in FIG. 2 , the drive unit 20 and the cover 15 are connected via an elastic body. In other words, the drive unit 20 (drive unit case 20a) is supported on the cover 15 (outer housing) via an elastic body. Furthermore, no elastic body is interposed between the motor unit 11 and the housing 14. That is, there is a space between the motor unit 11 and the housing 14 (i.e., the motor unit 11 and the housing 14 are separated). More specifically, the outer surface of the motor unit 11 (motor case 11b) is not in contact with the housing 14. In this embodiment, a U-shaped elastic member 22 will be described as an example of the elastic body. That is, the drive unit 20 and the cover 15 are connected via the U-shaped elastic member 22. Note that the U-shaped elastic member 22 is hatched in areas other than the cross section to make the positional relationship easier to understand.As shown in FIG. 4 , the drive unit 20 (drive unit case 20a) is formed in a generally cylindrical shape, and a U-shaped elastic member 22 is provided along the outer periphery of the cylindrical drive unit 20. In other words, as shown in FIGS. 5 and 6 , the U-shaped elastic member 22 is disposed so as to surround the outer periphery of the cylindrical drive unit 20. Meanwhile, the motor unit 11 (electric motor 11a) is connected to the housing 14 without an elastic body (it is separated from the outer housing). Note that the term "elastic body (damper)" as used herein refers to a material that deforms when subjected to an external force and returns to its original shape when the external force is removed. Examples of such materials include rubber, urethane, sponge, and spring.

[0024] Here, the U-shaped elastic member 22 assembled to the work machine 10 will be described. The U-shaped elastic member 22 is an elastic body made of rubber or the like, and includes a first elastic body 23 and a second elastic body 24 arranged at different positions in a direction intersecting the left-right direction, as shown in FIG. 3 . Specifically, the U-shaped elastic member 22 includes the first elastic body 23 and the second elastic body 24 arranged at different positions in a direction intersecting the left-right direction (front-rear or up-down direction). The first elastic body 23 is a curved portion of the U-shaped elastic member 22, and the second elastic body 24 is a substantially straight portion of the U-shaped elastic member 22. The first elastic body 23 and the second elastic body 24 are arranged at different positions at least in the front-rear direction. That is, in this embodiment, the vibration damping mechanism connected to the drive unit 20 includes the first elastic body 23 and the second elastic body 24 arranged at different positions in a direction intersecting the left-right direction.

[0025] In addition, the U-shaped elastic member 22 includes a left-side elastic body 28 arranged on the left side of the drive unit 20 and a right-side elastic body 27 arranged on the right side of the drive unit 20, and in the U-shaped elastic member 22, the left-side elastic body 28 and the right-side elastic body 27 are integrated.

[0026] Furthermore, either the first elastic body 23 or the second elastic body 24 includes a protrusion (first elastic body) 25 connected to either the cover 15 or the drive unit 20 and having a first elastic modulus, and a base (second elastic body) 26 connected to the other of the cover 15 or the drive unit 20 and having a second elastic modulus greater than the first elastic modulus. Specifically, the U-shaped elastic member 22 includes U-shaped bases 26 arranged in parallel, one above the other, and protrusions 25 protruding outward from multiple locations on the periphery of each U-shaped base 26. Each of the multiple protrusions 25 has a small elastic modulus due to its small area. In other words, if the elastic modulus of the protrusions 25 is the first elastic modulus and the elastic modulus of the base 26 is the second elastic modulus, the first elastic modulus is smaller than the second elastic modulus, meaning that the protrusions 25 are softer than the bases 26. In other words, the bases 26 are harder than the protrusions 25.

[0027] The U-shaped elastic member 22 has a connecting portion 26a that connects two base portions 26 arranged in parallel above and below, and has openings, namely a first opening 22a, a second opening 22b, and a third opening 22c, in the area surrounded by the base portions 26 and the connecting portion 26a. The first opening 22a and the second opening 22b are provided to generally correspond to the area of ​​the first elastic body 23, and the third opening 22c is provided to generally correspond to the area of ​​the second elastic body 24. Furthermore, between the two parallel-arranged base portions 26, internal protrusions 25a are provided that protrude from the connecting portion 26a toward the inside of the first opening 22a, the second opening 22b, and the third opening 22c, respectively.

[0028] As shown in FIGS. 5 and 6 , the U-shaped elastic member 22 formed as described above is disposed so as to surround the outer periphery of the cylindrical drive unit 20. Therefore, in the work machine 10, the U-shaped elastic member 22 includes portions disposed on the left, right, and front sides of the drive unit 20. As shown in FIG. 4 , protruding flanges 20c are provided in parallel on the outer periphery of the cylindrical drive unit 20. Furthermore, protruding projections 20b are provided between the two rows of flanges 20c arranged vertically on the outer periphery of the drive unit 20. As shown in FIG. 5 , the U-shaped elastic member 22 is fitted between the two rows of flanges 20c arranged vertically. At this time, the projections 20b of the drive unit 20 are fitted into the second openings 22b of the U-shaped elastic member 22.

[0029] Furthermore, the first elastic body 23, which is the curved portion of the U-shaped elastic member 22, is located between the drive unit 20 and the cover 15 in the front-to-rear direction. Furthermore, the right elastic body 27 of the U-shaped elastic member 22 is located on the right side of the drive unit 20 in the left-to-right direction, between the drive unit 20 and the cover 15. Meanwhile, the left elastic body 28 of the U-shaped elastic member 22 is located on the left side of the drive unit 20 in the left-to-right direction, between the drive unit 20 and the cover 15. As shown in Figure 6, the front rib 15a of the cover 15 is fitted into the first opening 22a of the U-shaped elastic member 22, and the side rib 15b of the cover 15 is fitted into the third opening 22c of the U-shaped elastic member 22.

[0030] Furthermore, in the first opening 22a, the front rib 15a of the cover 15 engages with the internal protrusions 25a on both sides within the first opening 22a. Similarly, in the third opening 22c, the side ribs 15b of the cover 15 engage with the internal protrusions 25a on both sides within the third opening 22c. Furthermore, in the second opening 22b, the protrusions 20b on both the left and right sides of the drive unit 20 engage with the internal protrusions 25a on both sides within the second opening 22b.

[0031] Furthermore, the base 26 fitted between the protruding upper and lower flanges 20c of the drive unit 20 is interposed between the cover 15 and the drive unit 20 in the vertical direction because the front rib 15a of the cover 15 is fitted between the two upper and lower bases 26. In other words, the base 26 of the U-shaped elastic member 22 engages (abuts) with the cover 15 and the drive unit 20 in the vertical direction.

[0032] Furthermore, the protrusions 25 provided at multiple locations on the outer periphery of the base 26 are located between the cover 15 and the drive unit 20 in the front-to-rear or left-to-right direction. Specifically, the multiple protrusions 25 provided on the outer periphery of the base 26 engage with the cover 15 and the drive unit 20 via the base 26 in the front-to-rear direction, and also engage with the cover 15 and the drive unit 20 via the base 26 in the left-to-right direction.

[0033] With the above-described structure, the U-shaped elastic member 22 in the work machine 10 reduces the propagation of vibrations generated by the drive unit 20 to the cover 15 in the up-down, front-back, and left-right directions. In other words, the vibration transmitted to the operator during machining can be reduced, improving workability with the work machine 10. Furthermore, in this embodiment, the U-shaped elastic member 22 is provided only on the drive unit 20 side, and no elastic body is provided on the motor unit 11 side. This reduces the number of elastic body parts assembled to the work machine 10, thereby reducing the cost of the work machine 10 while reducing vibration. Furthermore, according to this embodiment, the motor unit 11 is not included in the vibration transmission path. This limits the vibration transmission path to the front end portion of the housing 14, allowing for a longer distance from the vibration source to the grip portion 14a located at the rear. The fact that the housing 14 is made of resin (and further includes an elastic portion for improving gripping performance) also reduces the vibration transmitted to the grip portion 14a. Even when the periphery of the motor portion 11 is held, the vibration is reduced, although not as much as when the grip portion 14a is held.

[0034] In the work machine 10, vibrations in the up-down direction are smaller than those in the front-to-rear and left-to-right directions. Therefore, by fitting the hard base 26 of the U-shaped elastic member 22 between the upper and lower flanges 20c of the drive unit 20, it is possible to easily control the up-down movement of the work machine 10 during processing. In other words, because the drive unit 20 is engaged with the hard (large elastic modulus) base 26 in the up-down direction, it is easy to control the up-down movement of the work machine 10. In other words, by supporting the drive unit 20 with a soft (small elastic modulus) elastic body in the direction of greater vibration (left-to-right or front-to-rear direction) and with a hard (large elastic modulus) elastic body in the direction of less vibration (up-to-down direction), it is possible to achieve both ease of control and low vibration. Furthermore, when the tool bit 52 is pressed, the drive unit 20 and motor unit 11 tend to rotate (around the left-right axis) around the intersection of the first axis A1 and the second axis B1 (the support point of the drive unit 20). However, because the drive unit 20 is engaged with the hard base 26 (which has a large elastic modulus), this movement can be suppressed, improving workability (controllability). This rotation is primarily vertical. In particular, because the elastic body includes the first elastic body 23 and the second elastic body 24, which are positioned at different positions in a direction intersecting the left-right direction, this rotation can be effectively restricted.

[0035] Furthermore, the cover 15 engages with the soft internal protrusions 25a of the U-shaped elastic member 22 in the front-to-rear direction via the front ribs 15a and side ribs 15b, so vibrations in the front-to-rear direction can be effectively reduced.

[0036] Furthermore, the first elastic body 23 of the U-shaped elastic member 22 is positioned between the drive unit 20 and the cover 15 in the front-to-rear direction and engages with the drive unit 20 and the cover 15. In other words, since the first elastic body 23 of the U-shaped elastic member 22 is disposed on the front side of the drive unit 20, it is more effective in reducing vibrations in the front-to-rear direction of the work machine 10.

[0037] In the U-shaped elastic member 22, the right elastic body 27 and the left elastic body 28 are integrally formed via the first elastic body 23. Therefore, when assembling the U-shaped elastic member 22 to the drive unit 20, it is sufficient to simply fit the U-shaped elastic member 22 onto the outer periphery of the drive unit 20, thereby improving the ease of assembly of the work machine 10. Furthermore, because vibration reduction in the front-rear and left-right directions can be achieved by using only the U-shaped elastic member 22, which is a single member, it is possible to reduce vibration while minimizing the number of parts.

[0038] Next, a working machine 10 according to a first modified example of the present embodiment will be described.

[0039] The work machine 10 of the first modified example shown in Figures 7 to 10 has a structure in which an elastic body is provided on the rear side of the motor unit 11 as a vibration reduction measure. No elastic body is provided on the front side of the drive unit 20. That is, the drive unit 20 and the cover 15 are connected without an elastic body, and the motor unit 11 and the housing 14 are connected via an elastic body. Specifically, an elastic body 32a is interposed between the motor unit 11 (motor case 11b) and the housing 14, while the drive unit 20 and the cover 15 are connected directly or via a separate member (e.g., the same resin material as the housing 14) with greater rigidity than the elastic body 32a. Therefore, the first modified example also achieves a reduction in the number of elastic body parts, as in the above embodiment. A recess 20d is formed on the side of the drive unit 20. A protrusion 14d formed on the housing 14 engages (fits) with this recess 20d, thereby non-elastically connecting the drive unit 20 and the housing 14. In this embodiment, the recess 20d is separate from the drive unit 20 and is fixed to the drive unit 20 by adhesive. The recess 20d is made of resin, the same material as the housing 14. The protrusion 14d is formed on the inner wall of the housing 14 and is an integral structure that cannot be separated from the housing 14. A gap, particularly in the front-to-rear direction, is formed between the recess 20d and the protrusion 14d, allowing the inner unit to move relative to the housing 14 in the front-to-rear direction. Furthermore, this gap allows the inner unit (a drive unit consisting of the drive unit 20 and the motor unit 11) to swing slightly relative to the housing 14, with the recess 20d as a fulcrum. This allows the rear end of the inner unit to swing up and down or left and right (at the same time, the front end moves in the opposite direction) with the recess 20d as a fulcrum. The recess 20d may be formed integrally with the drive unit 20.

[0040] In the work machine 10 of the first modified example, the motor case 11b has a rearward extending portion 31 extending rearward from the rear end of the motor unit 11, and an elastic body 32a is interposed between the rearward extending portion 31 and the housing 14. As shown in FIGS. 11 and 12 , an annular elastic body 32a is fitted within the rearward extending portion 31 of the motor unit 11. Furthermore, a shaft 33 is fitted into a hole in the annular elastic body 32a. A central portion of the shaft 33 is a large-diameter portion 33b, and left and right sides of the large-diameter portion 33b are small-diameter portions 33a with smaller diameters than the large-diameter portion 33b. Both ends of the shaft 33 engage with the inner wall of the housing 14 and are supported by the housing 14. In other words, the motor unit 11 is supported by the housing 14 via the annular elastic body 32a and the shaft 33.

[0041] In the work machine 10 of the first modification, the rearward extending portion 31 is provided at the rear of the motor case 11b. This allows a portion of the drive unit 20, etc., away from the vibration center (i.e., a portion rearward of the electric motor 11a) to be supported via the elastic body 32a. This reduces vibration in the up-down, left-right, and front-back directions. More specifically, when the inner portion vibrates during operation, the elastic body 32a elastically deforms to cancel out the vibration of the inner portion when the rear portion of the inner portion moves up-down or left-right relative to the housing 14 around the recess 20d as a fulcrum, or when the inner portion moves in the front-back direction relative to the housing 14. Furthermore, because the large-diameter portion 33b of the shaft 33 is engaged with the elastic body 32a, vibration in the left-right direction in particular can be more effectively reduced. Furthermore, by providing the rearward extending portion 31 at the rear of the motor case 11b and supporting the motor unit 11 on this rearward extending portion 31 via the elastic body 32a, the support structure around the motor can be made compact, and soft elastic bodies can be used to ensure space.

[0042] The annular elastic body 32a and the case of the electric motor 11a have a half-body structure that can be separated into left and right halves. Therefore, when assembling the left and right cases, the shaft 33 is fitted into the hole of the elastic body 32a in one of the half-body structures of the case, which is previously assembled to the rearward extending portion 31, and then the other half-body structure of the elastic body 32a is assembled to the rearward extending portion 31. In this way, the elastic body 32a and the shaft 33 can be attached and the case can be assembled.

[0043] The second modified working machine 10 shown in FIGS. 13 and 14 also has a structure in which an elastic body is provided on the rear side of the electric motor 11a as a vibration reduction measure. The engagement structure between the recessed portion 20d and the protruding portion 14d is the same as that of the first modified working machine 10 (FIG. 9). In the second modified working machine 10, the motor unit 11 also has a rearward extending portion 31 extending rearward from the rear end of the motor case 11b, and an elastic body 32a is interposed between the rearward extending portion 31 and the housing 14. As shown in FIGS. 15 and 16, a semicircular elastic body 32b is fitted into the rearward extending portion 31 of the motor unit 11. The semicircular elastic body 32b is held by an engaging member 34, which engages with the inner wall of the housing 14 and is supported by the housing 14. In other words, the motor unit 11 is supported by the housing 14 via the semicircular elastic body 32b and the engaging member 34. It should be noted that the elastic body 32b may be formed in a single circle rather than a semicircle.

[0044] In the work machine 10 of the second modification, the rear extension 31 is provided behind the motor unit 11, so that the drive unit 20 and other parts at a location away from the vibration center (the location behind the motor unit 11) can be supported via the elastic body 32b. This reduces vibrations in the up-down, left-right, and front-rear directions.

[0045] 17 and 18 , a work machine 10 according to a third modification also has a structure in which an elastic body is provided on the rear side of the motor unit 11 as a vibration-reducing measure. The engagement structure between the recess 20d and the housing 14 is the same as that of the first modification ( FIG. 9 ). In the work machine 10 according to the third modification, the motor unit 11 also has a rearward extending portion 31 extending rearward from the rear end of the motor unit 11, and an elastic body 32c is interposed between the rearward extending portion 31 and the housing 14. As shown in FIGS. 19 and 20 , a circular elastic body 32c is fitted into the rearward extending portion 31 of the motor unit 11. The circular elastic body 32c has a recess 32d, and a protruding support portion 38 protruding from the inner wall of the housing 14 engages with the recess 32d of the elastic body 32c, thereby supporting the motor unit 11 with the housing 14. In other words, the motor unit 11 is supported by the housing 14 via the circular elastic body 32c and the protruding support portion 38.

[0046] In the work machine 10 of the third modification, the rearward extending portion 31 is provided behind the motor unit 11, so that a portion of the drive unit 20 and the like that is distant from the vibration center (a portion behind the motor unit 11) can be supported via the elastic body 32c. This reduces vibration in the up-down, left-right, and front-rear directions. Furthermore, the protruding support portion 38 that engages with the elastic body 32c is provided integrally with the inner wall of the housing 14, so the number of intervening parts can be reduced.

[0047] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present invention. For example, in the above-described embodiment, the U-shaped elastic member 22 is described as an elastic body in which the first elastic body 23 and the second elastic body 24 are integrated. However, the first elastic body 23 and the second elastic body 24 may be separate bodies. Furthermore, the protrusion portion (first elastic portion) 25 and the base portion (second elastic portion) 26 may also be separate bodies. For example, the protrusion portion 25 and the base portion 26 may be made of different rubbers and provided so as to overlap each other.

[0048] Furthermore, the U-shaped elastic member 22 may be attached to the rear end of the case of the electric motor 11a instead of being attached to the drive unit 20.

[0049] 10...Work machine, 11...Motor unit, 11a...Electric motor, 12...Device body, 13...Battery pack, 14...Housing (outer housing), 15...Cover (housing, outer housing), 15a...Front rib, 15b...Side rib, 16...Mounting portion, 17...Motor shaft, 18...Main switch, 19...Slide switch, 20...Drive unit (head unit), 20a...Drive unit case, 20b...Protrusion, 20c...Flange, 21...Controller, 22...U-shaped elastic member (elastic body), 23...First elastic body, 24...Second elastic body, 25...Protrusion (first elastic portion), 25a...internal protrusion portion, 26...base portion (second elastic portion), 27...right side elastic body, 28...left side elastic body, 29...holder, 30...output shaft, 31...rear extension portion, 32a, 32b, 32c...elastic bodies, 32d...recess, 33...shaft, 33a...small diameter portion, 33b...large diameter portion, 34...engaging member, 35...power transmission mechanism, 36...spindle, 38...protrusion support portion, 39...eccentric shaft, 40...ball bearing, 41...swing arm, 42...first shaft, 46...second shaft, 52...tool bit, 55...tool fixing member, A1...first axis, B1...second axis

Claims

1. a drive unit including a motor section and a drive section disposed in front of the motor section and fixed to the motor section; an output shaft supported by the drive unit and extending in a vertical direction; a housing that accommodates the motor unit; having The drive unit is a work machine, wherein the drive portion and the housing are connected via an elastic body, and the drive unit is supported by the housing in a state in which the motor portion and the housing are not connected.

2. a drive unit including a motor section and a drive section disposed in front of the motor section and fixed to the motor section; An output shaft supported by the drive unit; a housing that accommodates the motor unit; having The drive unit is supported by the housing with the drive portion and the housing inelastically connected and the motor portion and the housing connected via an elastic body.

3. The work machine according to claim 1 , wherein the elastic body includes a first elastic body and a second elastic body that are arranged at different positions in a direction intersecting with the left-right direction.

4. The work machine according to claim 3 , wherein the first elastic body and the second elastic body are disposed at different positions in the front-rear direction.

5. Either the first elastic body or the second elastic body is a first elastic portion having a first elastic modulus connected to either the housing or the drive portion; The work machine according to claim 3 or 4, further comprising: a second elastic portion having a second elastic modulus greater than the first elastic modulus, the second elastic portion being connected to the other of the housing or the drive portion.

6. The work machine according to claim 5 , wherein the second elastic portion is interposed between the housing and the drive portion in the vertical direction.

7. The work machine according to claim 5 , wherein the first elastic portion is located between the housing and the drive portion in the front-rear direction or the left-right direction.

8. The work machine according to claim 1 , wherein the elastic body is located between the drive unit and the housing in the front-rear direction.

9. 2. The work machine according to claim 1, wherein the elastic body includes a left elastic body arranged on the left side of the drive unit and a right elastic body arranged on the right side of the drive unit, the left elastic body and the right elastic body being integrated together.

10. The elastic body is a U-shaped elastic member, The work machine according to claim 1 , wherein the U-shaped elastic member includes portions disposed respectively on the left side, the right side, and the front side of the drive unit.

11. the drive unit and the housing are connected directly or via a member having a greater rigidity than the elastic body, The work machine according to claim 2 , wherein the elastic body is interposed between the motor unit and the housing.

12. the motor portion has a rear extension portion extending rearward from a rear end of the motor portion, The work machine according to claim 10 , wherein the elastic body is interposed between the rear extension and the housing.

13. A drive unit including a motor section and a drive section disposed in front of the motor section and fixed to the motor section; an output shaft supported by the drive unit and extending in a vertical direction; a housing that accommodates the motor unit; An elastic body provided forward of the drive unit; having The drive unit and the housing are connected in the front-rear direction via the elastic body.

14. A work machine as described in Claim 13, wherein the elastic body is U-shaped, and the drive unit and the housing are connected in the left-right direction via the elastic body.