Work equipment

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

Technical Field

[0004] , ,

[0008] , , , , , , , ,

[0006] , , , ,

[0005] , , , , , , , ,

[0007] ,

[0001] The present invention relates to a working machine. <0​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The work machine of the present invention comprises a drive unit having a motor section and a drive section positioned in front of the motor section and fixed to the motor section, an output shaft supported by the drive section and extending in the vertical direction, and housing the motor section. It has a gripping part that can be grasped by the worker. The drive unit has a housing and the drive unit is supported by the housing in a state where the drive unit and the housing are connected via an elastic body, and the motor unit and the housing are not connected. 。 [Effects of the Invention]

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

[0010] [Figure 1] This is a side cross-sectional view showing the structure of the work machine according to Embodiment 1 of the present invention. [Figure 2] Figure 1 is a cross-sectional view showing the arrangement structure of elastic bodies in the work machine. [Figure 3] Figure 1 is a perspective view showing the structure of the elastic body to be assembled to the work machine. [Figure 4] Figure 3 is a partial perspective view showing the structure of the drive unit into which the elastic body is fitted. [Figure 5] Figure 4 is a partial perspective view showing the state in which the elastic body is fitted into the drive unit. [Figure 6] Figure 5 is a cross-sectional perspective view showing the structure cut horizontally. [Figure 7] This is a cross-sectional view showing the structure of a work machine according to a first modified embodiment of the present invention. [Figure 8] Figure 7 is a cross-sectional view showing the arrangement structure of elastic bodies in the work machine. [Figure 9] This is a cross-sectional view of AA in Figure 8. [Figure 10] Figure 9 is a perspective view showing the structure of the rearward-extending portion of the work machine. [Figure 11] Figure 10 is a cross-sectional perspective view showing the rearward-extending portion cut vertically. [Figure 12]It is a cross-sectional perspective view showing the rear extending portion of FIG. 11 cut in the horizontal direction. [Figure 13] It is a cross-sectional view showing the arrangement structure of the elastic body in the working machine of the second modification of the embodiment of the present invention. [Figure 14] It is a perspective view showing the structure of the rear extending portion of the working machine of FIG. 13. [Figure 15] It is a cross-sectional perspective view showing the rear extending portion of FIG. 14 cut in the vertical direction. [Figure 16] It is a cross-sectional perspective view showing the rear extending portion of FIG. 14 cut in the horizontal direction. [Figure 17] It is a cross-sectional view showing the arrangement structure of the elastic body in the working machine of the third modification of the embodiment of the present invention. [Figure 18] It is a perspective view showing the structure of the rear extending portion of the working machine of FIG. 17. [Figure 19] It is a cross-sectional perspective view showing the rear extending portion of FIG. 18 cut in the vertical direction. [Figure 20] It is a cross-sectional perspective view showing the rear extending portion of FIG. 18 cut in the horizontal direction.

Embodiments for Carrying Out the Invention

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

[0012] The working machine 10 shown in FIG. 1, also called a multi-tool, etc., has a device body 12 that houses a motor unit 11 (an electric motor 11a and a motor case 11b), and a battery pack 13 that supplies power to the electric motor 11a. The battery pack 13 can be attached to and detached from the device body 12. The working machine 10 is a cordless type in which a power cord for connecting to a commercial power outlet is not provided on the device body 12. Also, in the cross-sectional view, the positional relationship is clearly shown by applying hatching to the members.

[0013] The device 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 positioned 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 an integral part (a single continuous component), and the cover 15 covers the drive unit (head unit) 20 connected to the motor unit 11. That is, the housing portion located in front of the motor unit 11 is the cover 15. The motor unit 11 and the drive unit 20 are integrally connected by fixing elements such as screws. The housing 14 is cylindrical and has a mounting portion 16. The mounting portion 16 is provided on the opposite side from the end to which the cover 15 is attached in a direction along the first axis A1. The battery pack 13 is attached to and detached from the mounting portion 16. The housing 14 is provided with a gripping portion 14a with a smaller diameter than the portion that houses the electric motor 11a. The operator can perform the work by gripping the gripping portion 14a. The housing 14 and cover 15 are an integrated (single continuous component) but are configured to be separable in the left-right direction. The housing 14 and cover 15 are made of resin. Although not shown in the illustration, an elastic portion (elastomer) is integrally molded onto the outer surface of the housing 14 and cover 15 (mainly around the gripping portion 14a) to improve grip strength. The technique of integrally molding an elastic portion (elastomer) into a resin housing is a well-known technique. The electric motor 11a, which is the power source, is housed in a motor case 11b and installed inside the housing 14. The electric motor 11a has a motor shaft 17. A main switch 18 is installed inside 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 gripping portion 14a). The slide switch 19 is movable along the housing 14, and moving it can turn the main switch 18 on and off. Furthermore, a controller 21 is installed inside the housing 14. The controller 21 is a known microcomputer equipped with a drive circuit, an arithmetic unit, a memory unit, input ports, output ports, and the like.

[0014] Furthermore, a holder 29 made of synthetic resin is provided inside the housing 14 (cover 15). The front end of the holder 29 is connected to the rear end 11d of the 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] Furthermore, the drive unit 20 is housed inside the cover 15. The drive unit 20 has a drive unit case 20a, and the output shaft 30 is supported (housed) in the drive unit case 20a. 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] Furthermore, a power transmission mechanism 35 is provided within the drive unit case 20a. The power transmission mechanism 35 is a mechanism that converts the rotational force of the motor shaft 17 into a force that causes the output shaft 30 to reciprocate within a predetermined angle range. The power transmission mechanism 35 is equipped with a spindle 36 that rotates integrally with the motor shaft 17. This 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. The inner ring of a ball bearing 40 is attached to the outer circumferential surface of the eccentric shaft 39.

[0017] A swing arm 41 is provided to connect the outer ring of the ball bearing 40 to 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 sections extending parallel to the motor shaft 17. The pair of arm sections are spaced at an interval equal to the outer diameter of the outer ring of the ball bearing 40. The pair of arm sections 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 sections.

[0018] Furthermore, the drive unit 20 has a first shaft 42 that is movable in a direction along the second axis B1 and is provided within the drive unit case 20a. In addition, the drive unit 20 has a second shaft 46 that is located within 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 can move 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] Furthermore, a tool fixing member 55 is provided at the tip of the second shaft 46, and the tip tool 52 is attached to the output shaft 30 by clamping the tip tool 52 between the tool fixing member 55 and the output shaft 30. Since the attachment and detachment structure of the tip tool 52 in this embodiment is the same as that described in the prior art documents, a more detailed explanation will be omitted.

[0020] Then, in the work machine 10, with the battery pack 13 attached to the mounting section 16, when the operator operates the slide switch 19 and the main switch 18 is turned on, power from the battery pack 13 is supplied to the electric motor 11a via the controller 21, and the motor shaft 17 of the electric motor 11a rotates. Conversely, when the slide switch 19 is operated and the main switch 18 is turned off, power from the battery pack 13 is no longer supplied to the electric motor 11a, and the motor shaft 17 of the electric motor 11a stops.

[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 the spindle 36 rotate together. When the spindle 36 rotates, the eccentric shaft 39 and the ball bearing 40 revolve around the first axis A1. When the ball bearing 40 revolves around the first axis A1, the swing arm 41 reciprocates (oscillates) within a predetermined angle range with the output shaft 30 as the pivot point. As a result, the output shaft 30 alternately rotates in the forward direction and in the reverse direction within a predetermined angle range with the second axis B1 as the center. In this way, the rotational force of the electric motor 11a is converted into the rotational force (vibration force) of the output shaft 30.

[0022] When the output shaft 30 rotates in both forward and reverse directions within a predetermined angle range, the tip tool 52 also rotates within a predetermined angle range around the second axis B1. Then, when the tip tool 52 is pressed against an object, the object can be processed, for example, by cutting or grinding.

[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 fixing elements 50 such as screws. That is, the motor unit 11 and the drive unit 20, which are each composed of separate components, are integrated and supported as an inner unit (drive unit) in the outer housing (housing 14, cover 15). Therefore, in the work machine 10, the motor unit 11 and the drive unit 20 vibrate together during operation. Accordingly, it is necessary to consider reducing the vibration transmitted to the operator. Regarding vibration, in the configuration of this embodiment, vibration in the left-right direction occurs due to the reciprocating motion of the output shaft 30 and the swing arm 41 in the left-right direction. In addition, since the swing arm 41 vibrates in the left-right direction around the second axis B1, motion in the front-rear direction also occurs (especially at the rear end), and vibration in the front-rear direction also occurs due to this motion. In the up-down direction, the vibration is smaller compared to the left-right and front-rear directions. When considering vibration, it is conceivable to place an elastic body (damper) between the vibration source and the worker's hand (gripping part 14a). However, since the vibration source can move relative to the gripping part 14a (housing 14), it is important to consider how to restrict this relative movement while damping vibration. Also, the amplitude of the vibration source may differ depending on the location. In the work machine 10 of this embodiment, as shown in Figure 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 by the cover 15 (outer housing) via an elastic body. Furthermore, the motor unit 11 and the housing 14 are configured so that there is no elastic body between them. That is, there is 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 in a non-contact state with the housing 14. In this embodiment, as an example of an elastic body, the case in which the elastic body is a U-shaped elastic member 22 will be described. In other words, the drive unit 20 and the cover 15 are connected via a U-shaped elastic member 22. Furthermore, to make the positional relationship of the U-shaped elastic member 22 easier to understand, hatching has been applied not only to the cross-sectional area but also to other parts of the image.The drive unit 20 (drive unit case 20a) is formed in a substantially cylindrical shape, as shown in Figure 4, and a U-shaped elastic member 22 is provided along the outer circumference of the cylindrical drive unit 20. In other words, the U-shaped elastic member 22 is arranged to surround the outer circumference of the cylindrical drive unit 20, as shown in Figures 5 and 6. On the other hand, the motor unit 11 (electric motor 11a) is connected to the housing 14 without an elastic body (it is separated from the outer housing). In this application, an elastic body (damper) 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 include rubber, urethane, sponge, and springs.

[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 as shown in Figure 3, includes a first elastic body 23 and a second elastic body 24 arranged at different positions in a direction intersecting the left-right direction. Specifically, the U-shaped elastic member 22 comprises a first elastic body 23 and a second elastic body 24 arranged at different positions in a direction intersecting the left-right direction (front-back direction or up-down direction). The first elastic body 23 is the curved portion of the U-shaped elastic member 22, and the second elastic body 24 is the substantially straight portion of the U-shaped elastic member 22. At least in the front-back direction, the first elastic body 23 and the second elastic body 24 are arranged at different positions. That is, this embodiment has a first elastic body 23 and a second elastic body 24 arranged at different positions in a direction intersecting the left-right direction as a vibration damping mechanism connected to the drive unit 20.

[0025] Furthermore, the U-shaped elastic member 22 includes a left-side elastic body 28 positioned on the left side of the drive unit 20 and a right-side elastic body 27 positioned 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 is connected to either the cover 15 or the drive unit 20 and includes a projection (first elastic part) 25 with a first elastic modulus, and a base (second elastic part) 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, in the U-shaped elastic member 22, U-shaped base parts 26 are provided in parallel, one above the other, and projections 25 that protrude outward are provided at multiple locations on the outer circumference of each U-shaped base part 26. Each of the multiple projections 25 has a small area and therefore a small elastic modulus. In other words, if the elastic modulus of the projection 25 is the first elastic modulus and the elastic modulus of the base part 26 is the second elastic modulus, then the first elastic modulus < the second elastic modulus, meaning the projection 25 is softer than the base part 26. To put it another way, the base part 26 is harder than the projection 25.

[0027] Furthermore, the U-shaped elastic member 22 has a connecting portion 26a that connects two base portions 26 arranged in parallel vertically, and has openings, a first opening 22a, a second opening 22b, and a third opening 22c, in the portion enclosed by the base portions 26 and the connecting portion 26a. The first opening 22a and the second opening 22b are provided to substantially correspond to the region of the first elastic body 23, and the third opening 22c is provided to substantially correspond to the region of the second elastic body 24. In addition, between the two base portions 26 arranged in parallel, there are internal projections 25a 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] The U-shaped elastic member 22, formed in the above shape, is arranged to surround the outer circumference of the cylindrical drive unit 20, as shown in Figures 5 and 6. Therefore, in the work machine 10, the U-shaped elastic member 22 includes portions that are positioned on the left, right, and front sides of the drive unit 20. As shown in Figure 4, protruding flange portions 20c are provided in parallel vertically on the outer circumference of the cylindrical drive unit 20. Furthermore, between the flange portions 20c arranged in two vertical rows on the outer circumference of the drive unit 20, projections 20b that protrude in the left-right direction are provided. The U-shaped elastic member 22 is then fitted between the flange portions 20c arranged in two vertical rows, as shown in Figure 5. At this time, the projections 20b of the drive unit 20 are fitted into the second opening 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-rear direction. In addition, the right elastic body 27 of the U-shaped elastic member 22 is located to the right of the drive unit 20 in the left-right direction, between the drive unit 20 and the cover 15. On the other hand, the left elastic body 28 of the U-shaped elastic member 22 is located to the left of the drive unit 20 in the left-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 projections 25a on both sides within the first opening 22a. Similarly, in the third opening 22c, the side rib 15b of the cover 15 engages with the internal projections 25a on both sides within the third opening 22c. Furthermore, in the second opening 22b, the projections 20b on both the left and right sides of the drive unit 20 engage with the internal projections 25a on both sides within the second opening 22b.

[0031] Furthermore, the base portion 26 fitted between the protruding upper and lower flange portions 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 base portions 26. In other words, the base portion 26 of the U-shaped elastic member 22 engages (contacts) with the cover 15 and the drive unit 20 in the vertical direction.

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

[0033] With the above structure, the U-shaped elastic member 22 is provided in the work machine 10, which reduces the transmission of vibrations generated in the drive unit 20 to the cover 15 in the vertical, horizontal, and lateral directions. In other words, vibrations transmitted to the operator during processing can be reduced, improving the workability of 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 interposed on the motor unit 11 side. Therefore, the number of elastic body parts assembled to the work machine 10 can be reduced, and the cost of the work machine 10 can be reduced while reducing vibrations of the work machine 10. In addition, according to this embodiment, the motor unit 11 is not included in the vibration transmission path. In this way, the vibration transmission path is limited to the front end portion of the housing 14, and the distance over which vibrations are transmitted from the source of vibration to the gripping portion 14a located at the rear can be increased. Combined with the fact that the housing 14 is made of resin (and further elastic parts are provided to improve grip), vibrations transmitted to the gripping portion 14a can be reduced even further. Furthermore, even when the motor section 11 is held, vibration will be reduced, though not to the same extent as with the gripping section 14a.

[0034] Furthermore, in the work machine 10, vertical vibrations are smaller than horizontal and longitudinal vibrations. Therefore, by fitting the rigid 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 vertical movement of the work machine 10 during processing. In other words, in the vertical direction, the drive unit 20 is engaged with the rigid (high elastic modulus) base 26, making it easier to control the vertical movement of the work machine 10. That is, by supporting the drive unit 20 with a soft (low elastic modulus) elastic body in the direction of large vibration (lateral or longitudinal direction) and with a rigid (high elastic modulus) elastic body in the direction of small vibration (vertical direction), it is possible to achieve both ease of control and low vibration. Furthermore, when the tip tool 52 is pushed in, the drive unit 20 and motor unit 11 attempt to rotate around the intersection of the first axis A1 and the second axis B1 (the support point of the drive unit 20) (with the left-right direction as the axis). However, because the drive unit 20 is engaged with the rigid (high elastic modulus) base 26, this movement can be suppressed, thereby improving workability (control performance). This rotation is mainly vertical. In particular, since the elastic body includes a first elastic body 23 and a second elastic body 24 positioned at different locations in a direction intersecting the left-right direction, this rotation can be effectively restricted.

[0035] Furthermore, since the cover 15 engages with the soft internal projection 25a of the U-shaped elastic member 22 in the front-rear direction through the front rib 15a and the side rib 15b, vibrations in the front-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-rear direction and engages with both the drive unit 20 and the cover 15. In other words, because the first elastic body 23 of the U-shaped elastic member 22 is positioned on the front side of the drive unit 20, it is more effective in reducing vibrations in the front-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 integrated via the first elastic body 23. Therefore, when assembling the U-shaped elastic member 22 to the drive unit 20, it is only necessary to fit the U-shaped elastic member 22 onto the outer circumference of the drive unit 20, thereby improving the ease of assembly of the work machine 10. Furthermore, since vibration reduction in the front-rear and left-right directions can be achieved with a single component, the U-shaped elastic member 22, vibration reduction can be achieved while keeping the number of parts down.

[0038] Next, a working machine 10, a first modified example of this embodiment, will be described.

[0039] The first modified work machine 10 shown in Figures 7 to 10 has a structure in which an elastic body is provided on the rear motor section 11 side as a measure to reduce vibration. No elastic body is provided on the front drive section 20 side. That is, the drive section 20 and the cover 15 are connected without an elastic body, and the motor section 11 and the housing 14 are connected via an elastic body. Specifically, an elastic body 32a is interposed between the motor section 11 (motor case 11b) and the housing 14, while the drive section 20 and the cover 15 are connected either directly or via a separate member with greater rigidity than the elastic body 32a (for example, a resin material similar to that of the housing 14). Therefore, in the first modified example as well, the number of elastic body parts can be reduced in the same way as in the above embodiment. A recess 20d is formed on the side surface of the drive section 20, and the drive section 20 and the housing 14 are connected non-elastically by the engagement (fitting) of a protrusion 14d formed on the housing 14 into this recess 20d. In this embodiment, the recess 20d is separate from the drive unit 20 and is fixed to the drive unit 20 by adhesive means. 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 has an integral structure that prevents it from being separated from the housing 14. A gap is formed between the recess 20d and the protrusion 14d, particularly in the front-rear direction, and this gap allows the inner part to move relative to the housing 14 in the front-rear direction. Furthermore, this gap allows the inner part (the drive unit consisting of the drive unit 20 and the motor unit 11) to swing slightly relative to the housing 14, using the position of the recess 20d as a pivot point. As a result, the inner part can swing its rear end up and down or left and right using the recess 20d as a pivot point (while simultaneously moving its front end in the opposite direction). The recess 20d may be formed integrally with the drive unit 20.

[0040] In the first modified working machine 10, the motor case 11b has a rearward extension portion 31 that extends rearward from the rear end of the motor unit 11, and an elastic body 32a is interposed between the rearward extension portion 31 and the housing 14. As shown in Figures 11 and 12, an annular elastic body 32a is fitted into the rearward extension portion 31 of the motor unit 11. Furthermore, a shaft 33 is fitted into the hole of the annular elastic body 32a. The central part of the shaft 33 is a large-diameter portion 33b with a larger diameter, and the left and right sides of the large-diameter portion 33b are small-diameter portions 33a with a smaller diameter 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 first modified work machine 10, a rearward extension 31 is provided behind the motor case 11b, allowing a part of the drive unit 20 and other components away from the vibration center (the rear part of the electric motor 11a) to be supported via the elastic body 32a. This reduces vibrations in the vertical, horizontal, and longitudinal directions. More specifically, when the inner part vibrates during operation, when the rear of the inner part moves vertically and horizontally relative to the housing 14 with the recess 20d as a pivot point, or when the inner part moves in the longitudinal direction relative to the housing 14, the elastic body 32a elastically deforms, thereby canceling out the vibrations of the inner part. Furthermore, since the large-diameter portion 33b of the shaft 33 is engaged with the elastic body 32a, vibrations can be reduced more effectively, especially in the horizontal direction. In addition, by providing a rearward extension 31 behind the motor case 11b, and supporting the motor unit 11 via the elastic body 32a in this rearward extension 31, the support structure around the motor can be made more compact, and a softer elastic body can be used to save space.

[0042] Furthermore, the case of the annular elastic body 32a and the electric motor 11a has a half-body structure that can be divided into left and right halves. Therefore, when assembling the left and right cases, the shaft 33 is inserted into the hole in the elastic body 32a of the case in which one half-body elastic body 32a has been pre-assembled to the rearward extension 31, and then the other case, in which the other half-body elastic body 32a has been pre-assembled to the rearward extension 31, is assembled. This allows the case to be assembled with the elastic body 32a and shaft 33 attached.

[0043] Furthermore, the second modified work machine 10 shown in Figures 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 measure to reduce vibration. The engagement structure of the recess 20d and the protrusion 14d is the same as in the first modified work machine (Figure 9). In the second modified work machine 10 as well, the motor unit 11 has a rearward extension 31 that extends rearward from the rear end of the motor case 11b, and an elastic body 32a is interposed between the rearward extension 31 and the housing 14. As shown in Figures 15 and 16, a semicircular elastic body 32b is fitted into the rearward extension 31 of the motor unit 11. The semicircular elastic body 32b is held by an engagement member 34, and this engagement member 34 engages with the inner wall of the housing 14 and is supported by the housing 14. That is, the motor unit 11 is supported by the housing 14 via the semicircular elastic body 32b and the engagement member 34. Furthermore, this can also be achieved by making the elastic body 32b a single circle instead of a semicircle.

[0044] In the second modified work machine 10, the rearward extension portion 31 is provided behind the motor unit 11, allowing the drive unit 20 and other parts located away from the vibration center (the rear side of the motor unit 11) to be supported via the elastic body 32b. This makes it possible to reduce vibrations in the vertical, horizontal, and longitudinal directions.

[0045] Furthermore, the third modified work machine 10 shown in Figures 17 and 18 also has a structure in which an elastic body is provided on the rear side of the motor section 11 as a measure to reduce vibration. The engagement structure between the recess 20d and the housing 14 is the same as in the first modified example (Figure 9). In the third modified work machine 10 as well, the motor section 11 has a rearward extension 31 that extends rearward from the rear end of the motor section 11, and an elastic body 32c is interposed between the rearward extension 31 and the housing 14. As shown in Figures 19 and 20, a circular elastic body 32c is fitted into the rearward extension 31 of the motor section 11. The circular elastic body 32c has a recess 32d, and a projection support portion 38 protruding from the inner wall of the housing 14 engages with this recess 32d of the elastic body 32c and is supported by the housing 14. That is, the motor section 11 is supported by the housing 14 via the circular elastic body 32c and the projection support portion 38.

[0046] In the third modified work machine 10, the rearward extension portion 31 is provided behind the motor unit 11, allowing the drive unit 20 and other parts located away from the vibration center (the rear side of the motor unit 11) to be supported via the elastic body 32c. This reduces vibrations in the vertical, horizontal, and longitudinal directions. Furthermore, since the projection support portion 38 that engages with the elastic body 32c is integrally provided with the inner wall of the housing 14, the number of intervening parts can be reduced.

[0047] The present invention is not limited to the embodiments described above, and can be modified in various ways without departing from its essence. For example, in the above embodiment, a U-shaped elastic member 22 in which a first elastic body 23 and a second elastic body 24 are integrated as an elastic body was described, but the first elastic body 23 and the second elastic body 24 may be separate. Furthermore, the projection (first elastic part) 25 and the base (second elastic part) 26 may also be separate. For example, the projection 25 and the base 26 may be made of different rubber and provided so that they overlap.

[0048] Alternatively, 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. [Explanation of symbols]

[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 part, 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 25a...Internal projection, 26...Base (second elastic part), 27...Right elastic body, 28...Left elastic body, 29...Holder, 30...Output shaft, 31...Rearward extension, 32a, 32b, 32c...Elastic body, 32d...Recess, 33...Shaft, 33a...Small diameter part, 33b...Large diameter part, 34...Engaging member, 35...Power transmission mechanism, 36...Spindle, 38...Projection support part, 39...Eccentric shaft, 40...Ball bearing, 41...Swing arm, 42...First shaft, 46...Second shaft, 52...Tip tool, 55...Tool fixing member, A1...First axis, B1...Second axis

Claims

1. A drive unit comprising a motor section and a drive section positioned in front of the motor section and fixed to the motor section, An output shaft supported by the aforementioned drive unit and extending in the vertical direction, A housing that houses the motor unit and has a gripping portion that can be grasped by an operator, It has, The drive unit is a work machine in which the drive unit and the housing are connected via an elastic body, and the motor unit and the housing are not connected, and the drive unit is supported by the housing.

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

3. The work machine according to claim 2, wherein the first elastic body and the second elastic body are arranged at different positions in the front-rear direction.

4. Either the first elastic body or the second elastic body is A first elastic part of the first elastic modulus connected to either the housing or the drive unit, The work machine according to claim 2 or 3, further comprising: a second elastic part having a second elastic modulus greater than the first elastic modulus, which is connected to the other of either the housing or the drive unit.

5. The work machine according to claim 4, wherein the second elastic portion is interposed between the housing and the drive unit in the vertical direction.

6. The work machine according to claim 4, wherein the first elastic portion is located between the housing and the drive unit in the front-rear or left-right direction.

7. 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.

8. The work machine according to claim 1, wherein the elastic body includes a left-side elastic body disposed on the left side of the drive unit and a right-side elastic body disposed on the right side of the drive unit, and the left-side elastic body and the right-side elastic body are integrated together.

9. 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 on the left, right, and front sides of the drive unit, respectively.

10. The motor section has a rearward-extending portion that extends rearward from the rear end of the motor section. The work machine according to claim 9, wherein the elastic body is interposed between the rearward-extending portion and the housing.

11. The work machine according to claim 1, wherein the drive unit and the housing are connected in the front-rear direction via the elastic body.

12. The work machine according to claim 11, 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.

Images