JP7338535B2 - work machine - Google Patents

Description

The present invention relates to working machines.

In the hammer drill described in Patent Document 1 below, a drive shaft of a motor that drives the hammer drill is supported by a pair of upper and lower bearings. The lower bearing is supported by the motor housing (outer housing). On the other hand, the upper bearing is accommodated and supported in the lower end portion of the gear housing (inner housing) (hereinafter referred to as the "bearing accommodating portion"), and the bearing accommodating portion is formed in a cylindrical shape. A bearing cover that covers the opening of the bearing accommodating portion is provided on the lower side of the gear housing. Further, the gear housing is arranged inside the motor housing, and the bearing accommodating portion is supported from the radially outer side by the support portion of the outer housing. Thereby, the upper bearing is supported by the motor housing via the gear housing. That is, the motor housing supports a pair of upper and lower bearings.

JP 2018-69397 A

Here, in the hammer drill of Patent Document 1, the support structure of the motor housing with respect to the gear housing is not described in detail, but the support structure is configured as follows. That is, the fixed arm portion for fixing the bearing cover is formed integrally with the bearing housing portion of the gear housing, and the fixed arm portion extends radially outward of the bearing housing portion. Therefore, in order to support the bearing accommodating portion from the radially outer side by the motor housing, it is necessary to form a notch portion in the support portion of the motor housing to avoid interference with the fixed arm portion. That is, the portion of the support portion of the motor housing that supports the bearing accommodating portion is formed in a non-circular shape. For this reason, there is a possibility that the assembly accuracy and support strength for the gear housing will be reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a work machine capable of improving assembly accuracy and support strength with respect to an inner housing.

According to one or more embodiments of the present invention, a drive source having a drive shaft, a mechanism portion operated by the driving force of the drive shaft, bearings rotatably supporting the drive shaft, and the mechanism portion are accommodated. and a second housing portion having a bearing support hole for supporting the bearing; A bearing cover that covers the driving source, the inner housing, and an outer housing that accommodates the bearing cover, wherein the bearing cover has a cylindrical supported portion that is coaxially arranged with the bearing. In the working machine, the outer housing is formed with a supporting portion that supports the supported portion from the radially outer side.

In one or more embodiments of the present invention, a portion to be fixed is formed on the outer peripheral portion of the second housing portion, and a fixing portion for fixing the portion to be fixed by a fixing member is formed on the bearing cover. and the positions of the supported portion, the fixed portion, and the fixed portion are shifted in the axial direction of the drive shaft.

In one or more embodiments of the present invention, the bearing cover has a cover body that covers the bearing support hole from one side in the axial direction of the drive shaft, and the supported portion extends from the cover body. The working machine extends to one side in the axial direction of the drive shaft.

In one or more embodiments of the present invention, a housing-side fitting portion arranged coaxially with the bearing is formed on an outer peripheral portion of the second housing portion at one axial end of the drive shaft. and the cover main body is provided with a cover-side fitting portion into which the housing-side fitting portion is fitted.

One or more embodiments of the present invention is a work machine in which the fixed portion and the fixed portion are provided at two locations radially outward of the bearing support hole.

One or more embodiments of the present invention is a work machine in which the fixing member is arranged on one side in the axial direction of the drive shaft with respect to the mechanism section.

In one or more embodiments of the present invention, the mechanism section includes a driven shaft extending in a direction intersecting the axial direction of the drive shaft, and the drive shaft has a bevel gear fitted with the driven shaft. It is a work machine that has

In one or more embodiments of the present invention, the bearing cover covers the bearing support hole from one side in the axial direction of the drive shaft, and the bevel gear moves toward the other side in the axial direction of the drive shaft. The working machine is composed of a plurality of gear teeth inclined radially inward.

In one or more embodiments of the present invention, the mechanism transmits rotational motion of the driven shaft to the tip tool, converts the rotational motion of the driven shaft into reciprocating motion, and applies an impact force to the tip tool. It is a working machine that gives

According to one or more embodiments of the present invention, assembly accuracy and support strength for the inner housing can be improved.

It is the side view seen from the left side which shows the hammer drill concerning this Embodiment. FIG. 2 is a longitudinal sectional view showing the inside of the hammer drill shown in FIG. 1; FIG. 3 is an exploded perspective view showing a state in which an upper motor bearing and a bearing cover are removed from the inner housing of the hammer drill shown in FIG. 2; FIG. 3 is a cross-sectional view (a cross-sectional view taken along line 4-4 in FIG. 2) seen from below showing a state in which the bearing cover of the hammer drill shown in FIG. 2 is supported by the support pieces of the body housing; FIG. 5 is a cross-sectional view (cross-sectional view taken along line 5-5 in FIG. 4) seen from the rear side showing a fixed state between the inner housing and the bearing cover shown in FIG. 4; (A) is a plan view seen from above the bearing cover shown in FIG. 5, and (B) is a side view seen from the rear side of the bearing cover in (A). 6 is a cross-sectional view corresponding to FIG. 5 showing an example in which the bearing cover is fitted to the second housing portion of the inner housing from the radially inner side; FIG. 5 is a cross-sectional view corresponding to FIG. 4, showing a modification of the support piece of the main body housing shown in FIG. 4; FIG.

A hammer drill 10 as a "working machine" according to the present embodiment will be described below with reference to the drawings. The hammer drill 10 is configured as a tool for drilling or the like on a workpiece. An arrow UP, an arrow FR, and an arrow LH appropriately shown in the drawings indicate the upper side, the front side, and the left side of the hammer drill 10 . In the following description, when the up-down, front-rear, and left-right directions are used, the up-down direction, front-rear direction, and left-right direction of the hammer drill 10 are indicated unless otherwise specified.

As shown in FIGS. 1 and 2, the hammer drill 10 includes an outer housing 12, an inner housing 30 housed in the outer housing 12, a motor 40 as a "driving source", and a driving force of the motor 40. It includes a driving mechanism portion 50 as a “mechanical portion” that drives, a battery pack 70 , and a control portion 80 that drives and controls the motor 40 . Further, the hammer drill 10 has an operation lever 68, and by operating the operation lever 68, the transmission path to the tip tool T in the drive mechanism section 50 is switched, and the hammer drill 10 moves to the tip tool T. It is configured to switch to a drill mode in which a rotational force is applied or a hammer drill mode in which the tip tool T is applied with a rotational force and a striking force. Furthermore, the hammer drill 10 has a support structure S applied to an upper motor bearing 45 that rotatably supports the drive shaft 41 of the motor 40 . Each configuration of the hammer drill 10 will be described below.

(Regarding the outer housing 12)
The outer housing 12 is hollow and constitutes the shell of the hammer drill 10 . The outer housing 12 has a body housing 13 forming a front portion of the outer housing 12 and a handle housing 16 forming a rear portion of the outer housing 12 . The handle housing 16 is formed in a substantially U-shape opened to the front when viewed from the left side, and the body housing 13 is formed in a substantially inverted L-shape when viewed from the side. Upper and lower ends of the handle housing 16 are connected to the body housing 13 by a connecting portion 17 made of an elastic material such as elastomer. A connecting plate 18 is provided inside the connecting portion 17, and the connecting plate 18 prevents the main body housing 13 and the handle housing 16 from being separated from each other by a predetermined distance or more in the front-rear direction.

A rear end portion of the handle housing 16 is configured as a grip portion 16A that is gripped by an operator, and the grip portion 16A extends vertically. Further, the connecting portion 17 described above extends rearward so as to cover the outer peripheral surface of the grip portion 16A. As a result, the connecting portion 17 is elastically deformed, so that the grip portion 16A (handle housing 16) can move relative to the outer housing 12 (main body housing 13) in the front-rear direction.

A trigger 20 is provided at the upper end of the grip portion 16A. A switch button 21 for switching the direction of rotation of a motor 40, which will be described later, is provided above the trigger 20. As shown in FIG. Furthermore, a switch mechanism 22 is provided behind the trigger 20 . The switch mechanism 22 has a switch (not shown) operated by the trigger 20 and the switching button 21 . The switch is electrically connected to a control section 80 to be described later, and is configured to output an output signal to the control section 80 according to the operating state of the trigger 20 and the switching state of the switching button 21 .

The body housing 13 includes a first body housing portion 14 and a second body housing portion 15 . The first body housing portion 14 is configured as a housing portion for accommodating a drive mechanism portion 50, which will be described later, and is formed in a substantially cylindrical shape with the front-rear direction as the axial direction. The second body housing portion 15 is configured as a housing portion for accommodating a motor 40 to be described later, extends vertically, and is connected to the rear end portion of the first body housing portion 14 . The second body housing portion 15 is divided into two in the left-right direction, and the second body housing portion 15 is formed by assembling the divided housings. A shift switch 23 is provided in the rear portion of the second body housing portion 15 in the middle portion in the vertical direction. The shift switch 23 is configured as a switch that switches the number of rotations of the motor 40 (described later) in multiple steps when operated, and is electrically connected to the control section 80 (described later).

Also, the lower end of the second body housing portion 15 protrudes downward from the handle housing 16 . That is, the lower rear corner of the outer housing 12 is notched in a concave shape that is open rearward and downward, and this portion is configured as a battery mounting portion 16B for mounting a battery pack 70, which will be described later. there is Furthermore, a connector 24 connected to the battery pack 70 is provided at the lower end of the handle housing 16 (below the grip portion 16A).

(Regarding the inner housing 30)
As also shown in FIG. 3, the inner housing 30 includes a first inner housing portion 31 as a "first housing portion" and a second inner housing portion 32 as a "second housing portion." there is The first inner housing portion 31 is formed in a substantially bottomed elliptical cylindrical shape that is open to the front side. The first inner housing portion 31 is arranged inside the first main body housing portion 14, closes the opening on the rear end side of the first main body housing portion 14, and separates the first main body housing portion 14 and the second main body housing portion 14 from each other. 15 and attached to the first body housing portion 14 . Thus, the first body housing portion 14 and the inner housing 30 constitute a driving mechanism housing portion 34 that houses a driving mechanism portion 50, which will be described later.

A cylinder support member 36 for supporting a cylinder 57, which will be described later, is fixed to the upper portion of the first inner housing portion 31. As shown in FIG. The cylinder support member 36 is formed in a substantially cylindrical shape whose axial direction is the front-rear direction.

The second inner housing portion 32 constitutes a lower end portion of the inner housing 30 and is configured as a housing portion for accommodating and supporting an upper motor bearing 45 to be described later. The configuration of the second inner housing portion 32 will be described later.

(Regarding the motor 40)
As shown in FIG. 2 , the motor 40 is configured as a three-phase brushless motor and housed within the second body housing portion 15 of the outer housing 12 . The motor 40 includes a drive shaft 41 whose axial direction is the vertical direction, a substantially cylindrical rotor 42 fixed to the drive shaft 41, and a substantially cylindrical stator 43 arranged radially outside the rotor 42. is composed of

A lower end (one end in the axial direction) of the drive shaft 41 is rotatably supported by a lower motor bearing 44 . is fixed to The fixed wall 15A is formed in a substantially rectangular plate shape whose plate thickness direction is the vertical direction, and is formed in a substantially U-shape opened upward when viewed from the left-right direction. Thereby, the lower motor bearing 44 is supported by the second body housing portion 15 . The upper end side (the other side in the axial direction) of the drive shaft 41 is inserted through the second inner housing portion 32 of the inner housing 30 . The upper end portion of the drive shaft 41 is rotatably supported by an upper motor bearing 45 as a "bearing", and the upper motor bearing 45 is supported and fixed to the second inner housing portion 32 of the inner housing 30. there is A support structure S for the upper motor bearing 45 will be described later.

The upper end portion of the drive shaft 41 is arranged inside the drive mechanism accommodating portion 34, and the upper end portion of the drive shaft 41 is formed with a motor-side bevel gear 41A as a "bevel gear." The motor-side bevel gear 41A is composed of a plurality of gear teeth, and the gear teeth are inclined radially inward toward the upper end side of the drive shaft 41 .

The stator 43 has a stator holder 43A, and stator coils 43B corresponding to the U-phase, V-phase, and W-phase of the motor 40 are wound around the stator holder 43A. The motor 40 is electrically connected to a control section 80 which will be described later. A fan 46 is provided on the upper end side of the drive shaft 41 at a position below the upper motor bearing 45 , and the fan 46 is fixed to the drive shaft 41 so as to be integrally rotatable. The fan 46 is configured as a so-called centrifugal fan, and configured to cause the air on the center side of the fan 46 to flow outward in the radial direction.

(Regarding the drive mechanism section 50)
The drive mechanism portion 50 includes an intermediate shaft 51 as a “driven shaft”, a cylinder 57, a piston 64, a striker 65, and a middle element 66, and is arranged inside the drive mechanism housing portion 34. It is

<Regarding the intermediate shaft 51>
The intermediate shaft 51 is formed in a substantially columnar shape whose axial direction is the front-rear direction, and is arranged in the lower portion of the drive mechanism accommodating portion 34 . A front end portion of the intermediate shaft 51 is rotatably supported by an intermediate bearing 52 fixed to the first main body housing portion 14 , and a rear end portion of the intermediate shaft 51 is held by an intermediate bearing 53 fixed to the inner housing 30 . rotatably supported. A shaft-side bevel gear 54 is fixed to the rear end portion of the intermediate shaft 51 , and the shaft-side bevel gear 54 meshes with the motor-side bevel gear 41 A of the motor 40 . As a result, the intermediate shaft 51 rotates around its own axis when the motor 40 is driven to rotate the drive shaft 41 .

An intermediate gear portion 51A is formed on the outer peripheral portion of the intermediate shaft 51 on the front end side. A substantially cylindrical clutch 55 is externally fitted on the intermediate shaft 51 on the rear side of the intermediate gear portion 51A. The clutch 55 is spline-fitted to the intermediate gear portion 51A. That is, the clutch 55 is coupled to the intermediate gear portion 51A so as to be relatively movable in the axial direction of the intermediate gear portion 51A and to rotate integrally with the intermediate gear portion 51A. A meshing portion 55A is formed at the rear end portion of the clutch 55 . A clutch groove 55B is formed in the outer peripheral portion of the front end portion of the clutch 55, and the clutch groove 55B extends in the circumferential direction of the clutch 55 and opens radially outward.

A motion converting member 56 is rotatably fitted around the intermediate shaft 51 behind the clutch 55 . The motion conversion member 56 is configured as a member that converts the rotational motion of the intermediate shaft 51 to reciprocate the later-described piston 64 in the front-rear direction. A meshing portion 56A is formed at the front end portion of the motion conversion member 56 . Then, the clutch 55 moves rearward, and the meshing portion 55A meshes with the meshing portion 56A, so that the clutch 55 and the motion converting member 56 are connected, and the motion converting member 56 is integrated with the intermediate shaft 51. It is configured to rotate to Further, the motion conversion member 56 has an arm portion 56B extending upward.

<Regarding the cylinder 57>
The cylinder 57 is formed in a substantially cylindrical shape whose axial direction is the front-rear direction, and is housed in the drive mechanism housing section 34 above the intermediate shaft 51 . A rear end portion of the cylinder 57 is rotatably supported by a cylinder bearing 58 , and the cylinder bearing 58 is fixed to the inner peripheral portion of the cylinder support member 36 . On the other hand, the front end portion of the cylinder 57 is rotatably supported by a cylinder bearing 59 , and the cylinder bearing 59 is fixed to the first body housing portion 14 via a support ring 60 . Also, the cylinder 57 is formed in a substantially stepped cylindrical shape, and the inner diameter of the front end portion of the cylinder 57 is set smaller than the inner diameter of the other portions. A tool holding portion 62 is attached to the front end portion of the cylinder 57, and the tool holding portion 62 detachably fixes the rear end portion of the tip tool T extending in the front-rear direction.

A flange 57</b>A projecting radially outward is formed at an axially intermediate portion of the cylinder 57 . A ring-shaped cylinder gear 63 is provided at the front portion of the flange 57A. An urging spring 67 configured as a compression coil spring is provided on the front side of the cylinder gear 63 . ing. Further, the cylinder gear 63 meshes with the intermediate gear portion 51A of the intermediate shaft 51 . As a result, the driving force of the motor 40 rotates the intermediate shaft 51 , thereby rotating the cylinder 57 and the tip tool T around the axis of the cylinder 57 .

<Regarding the piston 64>
The piston 64 is formed in a substantially bottomed cylindrical shape that is open forward, and is inserted into the rear portion of the cylinder 57 so as to be relatively movable in the front-rear direction. A piston connection portion 64A is formed on the bottom wall of the piston 64 and extends rearward. The piston connection portion 64A is provided with an upper end portion of an arm portion 56B of the motion conversion member 56 with the left-right direction as an axial direction. rotatably connected. Thus, when the motion conversion member 56 rotates integrally with the intermediate shaft 51, the piston 64 is reciprocated in the front-rear direction by the arm portion 56B.

<About the striker 65>
The striker 65 is formed in a substantially columnar shape whose axial direction is the front-rear direction, and is inserted inside the piston 64 so as to be relatively movable in the front-rear direction. A space between the bottom wall of the piston 64 and the striker 65 in the piston 64 is configured as an air chamber 64B. A recess 65A that opens forward is formed in the front surface of the striker 65 substantially at the center.

<Regarding Meson 66>
The intermediate element 66 is formed in a substantially columnar shape whose axial direction is the front-rear direction, and is inserted into the front end portion of the cylinder 57 so as to be relatively movable in the front-rear direction. Also, the rear end portion of the intermediate member 66 is arranged adjacent to the front side of the striking member 65 so as to be able to abut against the inside of the concave portion 65A of the striking member 65 . As a result, the piston 64 moves forward and the pressure in the air chamber 64B rises, so that the striker 65 and the intermediate member 66 move forward, and a striking force is applied to the tip tool T in the front-rear direction. It is configured to

(Regarding the operation lever 68)
As shown in FIG. 1, the operating lever 68 is rotatably provided on the left wall of the first body housing portion 14 of the hammer drill 10 and is exposed outside the first body housing portion 14 so as to be rotatable. ing. Specifically, the operating lever 68 is positioned at a hammer drill mode setting position indicated by a solid line in FIG. 1 and at a drill setting position rotated approximately 90 degrees from the hammer drill mode setting position (position indicated by a two-dot chain line in FIG. 1). and is configured to be rotatable between.

The operation lever 68 is configured as a member for switching the transmission path to the tip tool T of the drive mechanism section 50 . Further, in the hammer drill 10, the workpiece is machined in a state in which the tip tool T is pressed against the workpiece and a load is applied to the workpiece (hereinafter, this state is referred to as a loaded state). ing. Specifically, in the load state at the drill mode set position of the operation lever 68, the non-connected state between the clutch 55 and the motion conversion member 56 in the drive mechanism section 50 is maintained. As a result, the hammer drill 10 is put into the drill mode, and only the rotational force is applied to the tip tool T by the drive mechanism section 50 .

On the other hand, in the load state where the operating lever 68 is set to the hammer drill mode, the meshing portion 55A of the clutch 55 and the meshing portion 56A of the motion conversion member 56 in the drive mechanism portion 50 are meshed, and the clutch 55 and the motion conversion member 56 are engaged. is configured to be connected. As a result, the hammer drill 10 enters the hammer drill mode, and the tip tool T is provided with the rotational force and the impact force by the driving mechanism 50 .

(Battery pack 70)
Battery pack 70 is formed in a substantially rectangular parallelepiped shape. The battery pack 70 is attached to the battery attachment portion 16B of the outer housing 12 from the rear side. The battery pack 70 has a connector (not shown), and when the battery pack 70 is attached to the battery attachment portion 16B, the connector is connected to the connector 24 and power is supplied from the battery pack 70 to the control portion 80. It is configured to In addition, the battery pack 70 has a pair of lock members 70A, and the lock members 70A are provided on the left and right sides of the battery pack 70 . When the battery pack 70 is attached to the battery mounting portion 16B, the lock member 70A is engaged with the handle housing 16, and the rearward movement of the battery pack 70 is restricted.

A stopper member 25 made of an elastic material such as rubber is provided at the lower end portion (battery mounting portion 16B) of the second main body housing portion 15 described above. is located adjacent to the Thereby, the stopper member 25 functions as an abutting portion when the battery pack 70 is attached to the battery attachment portion 16B.

(Regarding the control unit 80)
The control section 80 is arranged at the lower end of the second main body housing section 15 . The control unit 80 is electrically connected to the switches of the switch mechanism 22 , the switching button 21 , the shift switch 23 , and the battery pack 70 . When the trigger 20 is pulled, the motor 40 is driven by the control section 80 , and the driving force of the motor 40 is transmitted to the tip tool T by the drive mechanism section 50 . Further, when the motor 40 is driven by the control unit 80, the rotation direction of the motor 40 is set according to the switching state of the switching button 21, and the motor 40 rotates at a rotation speed corresponding to the operation position of the shift switch 23. It has become.

(Regarding the support structure S for the upper motor bearing 45)
As shown in FIGS. 2 to 5, the support structure S includes the second inner housing portion 32 of the inner housing 30, the bearing cover 33, and the "support portion" formed in the second main body housing portion 15 of the outer housing 12. , and a pair of left and right support pieces 15B. Each configuration of the support structure S will be described below.

<Regarding the second inner housing portion 32>
The second inner housing portion 32 is formed in a substantially stepped cylindrical shape whose axial direction is the vertical direction, and extends downward from the first inner housing portion 31 of the inner housing 30 . Specifically, the diameter of the lower portion of the second inner housing portion 32 is set larger than the diameter of the upper portion of the second inner housing portion 32 . An insertion portion 32</b>A that penetrates vertically is formed inside the second inner housing portion 32 , and the insertion portion 32</b>A communicates with the inside of the first inner housing portion 31 . A drive shaft 41 of the motor 40 is inserted through the insertion portion 32A.

A bearing accommodating portion 32B as a “bearing support hole” for accommodating the upper motor bearing 45 is formed in the lower opening of the second inner housing portion 32 . The bearing housing portion 32B is formed in a concave shape that opens downward, is formed in a circular shape with a larger diameter than the insertion portion 32A when viewed from below, and is arranged coaxially with the drive shaft 41 . The upper motor bearing 45 is fitted into the bearing accommodating portion 32B from below and fixedly supported by the second inner housing portion 32 .

A washer housing portion 32C is formed inside the second inner housing portion 32 above the bearing housing portion 32B. The washer housing portion 32C is formed in a concave shape that opens downward, and is formed in a circular shape having a larger diameter than the insertion portion 32A and a smaller diameter than the bearing housing portion 32B when viewed from below. A washer 47 (not shown in FIG. 2) is accommodated in the washer accommodation portion 32C.

A housing-side fitting portion 32</b>D is formed on the outer peripheral portion of the lower end portion of the second inner housing portion 32 . When viewed from below, the housing-side fitting portion 32D is formed in a circular shape that is one step lower in the radial direction than the outer periphery of the lower portion of the second inner housing portion 32, and is formed concentrically with the bearing accommodating portion 32B. It is A pair of left and right housing-side fixing arms 32E as "fixed portions" are formed on the outer peripheral portion of the lower portion of the second inner housing portion 32 above the housing-side fitting portion 32D. The housing-side fixed arm 32E extends laterally outward from the second inner housing portion 32 . A fixing hole 32F is vertically formed through the tip of the housing-side fixing arm 32E.

<Regarding the bearing cover 33>
As also shown in FIG. 6, the bearing cover 33 has a cover main body 33A, and the cover main body 33A is formed in a substantially ring-shaped plate having a plate thickness direction in the vertical direction. A cover-side fitting portion 33B is formed on the upper surface of the cover main body 33A. The cover-side fitting portion 33</b>B is formed in a concave shape that opens upward, is formed in a circular shape when viewed from above, and is arranged coaxially with the drive shaft 41 . The housing-side fitting portion 32D of the second inner housing portion 32 is fitted into the cover-side fitting portion 33B from above, and the second inner housing portion 32 is fitted to the bearing cover 33. As shown in FIG. That is, the bearing cover 33 is fitted to the second inner housing portion 32 from the radial outside. As a result, the cover body 33A covers the outer peripheral portion of the opening of the bearing accommodating portion 32B in the second inner housing portion 32 from below, and is arranged adjacent to the lower side of the outer peripheral portion of the upper motor bearing 45 . That is, the bearing cover 33 is configured to restrict the downward movement of the upper motor bearing 45 . When the bearing cover 33 and the inner housing 30 are fitted together, the drive shaft 41 of the motor 40 passes through the cover main body 33A.

A cover-side fixing arm 33C as a pair of left and right "fixing portions" is formed on the outer peripheral portion of the cover main body 33A. The cover-side fixed arm 33C extends laterally outward from the cover main body 33A, and the lower surface of the cover-side fixed arm 33C and the lower surface of the cover main body 33A are flush with each other. A fixed tubular portion 33D is integrally formed at the tip of the cover-side fixed arm 33C. The fixed tubular portion 33</b>D is formed in a substantially cylindrical shape whose axial direction is the vertical direction, and is arranged coaxially with the fixed hole 32</b>F of the inner housing 30 . A female thread is formed on the inner peripheral surface of the fixed tubular portion 33D. Further, the fixed tubular portion 33D projects upward from the cover main body 33A and the cover-side fixed arm 33C, and the upper end surface of the fixed tubular portion 33D is arranged adjacent to the lower side of the tip portion of the housing-side fixed arm 32E. It is A fixing bolt 37 as a "fixing member" is inserted into the fixing hole 32F from above and screwed into the inner peripheral portion of the fixing cylindrical portion 33D, thereby fixing the inner housing 30 (second inner housing portion 32) to the bearing. It is fixed to the cover 33 . In addition, the fixing bolt 37 is arranged close to the lower side of the first inner housing portion 31 of the inner housing 30 .

A supported tubular portion 33E as a "supported portion" is formed on the lower surface of the cover main body 33A. The supported tubular portion 33E is formed in a cylindrical shape having an axial direction in the vertical direction, extends downward from the cover main body 33A, and is arranged coaxially with the cover-side fitting portion 33B. That is, the supported tubular portion 33E is arranged below the cover main body 33A and the cover-side fixed arm 33C. In addition, a support groove 33F is formed in the outer peripheral portion of the supported tubular portion 33E, and the support groove 33F is open radially outward of the supported tubular portion 33E and extends in the circumferential direction of the supported tubular portion 33E. It is formed all around. The bottom surface of the support groove 33F is configured as a supported surface 33G, and the supported surface 33G is arranged coaxially with the cover-side fitting portion 33B. That is, the supported surface 33G (supported tubular portion 33E) is arranged coaxially with the bearing accommodating portion 32B (upper motor bearing 45). Further, the supported surface 33G (supported cylindrical portion 33E) is configured as a portion supported by a support piece 15B described later. That is, the portion of the bearing cover 33 supported by the support piece 15B is formed in a circular shape.

<Regarding the support piece 15B>
As shown in FIGS. 2 to 5, the support piece 15B is formed integrally with the second body housing portion 15 of the outer housing 12 and arranged inside the second body housing portion 15. As shown in FIGS. The support piece 15B is formed in a plate shape having a plate thickness direction in the vertical direction, and extends inward in the left-right direction (center side) from left and right side walls of the second main body housing portion 15 (see FIG. 4). . Further, the support piece 15B is arranged radially outside the supported tubular portion 33E (support groove 33F) of the bearing cover 33 . Thereby, the support piece 15B is arranged below the cover main body 33A of the bearing cover 33 and the cover-side fixed arm 33C.

A circular arc-shaped support portion 15B1 is formed at the tip of the support piece 15B. The arcuate support portion 15B1 is formed in a substantially semicircular shape that opens toward the center in the left-right direction in a plan view. Also, the plate thickness dimension of the support piece 15B is set slightly smaller than the width dimension (vertical dimension) of the support groove 33F of the bearing cover 33 . The edge of the arcuate support portion 15B1 is inserted into the support groove 33F of the bearing cover 33. As shown in FIG. As a result, the position of the bearing cover 33 relative to the outer housing 12 (second main body housing portion 15) in the vertical direction is determined by the support pieces 15B. Further, the supported surface 33G of the support groove 33F is arranged adjacent to the radially inner side of the arcuate support portion 15B1, and the supported cylindrical portion 33E (bearing cover 33) is supported from the radially outer side by the arcuate support portion 15B1. It is Thereby, the position of the bearing cover 33 with respect to the outer housing 12 (second main body housing portion 15) in the front-rear direction and the left-right direction is determined by the support pieces 15B.

In addition, as described above, the second main body housing portion 15 is divided into two in the left-right direction. Therefore, the supported tubular portion 33E of the bearing cover 33 is sandwiched from the outside in the left-right direction by the pair of support pieces 15B and supported. A pair of front and rear abutment portions 15B2 are formed at the tip portion of the support piece 15B on both sides in the front-rear direction with respect to the arc-shaped support portion 15B1. The abutting portion 15B2 is configured as a surface perpendicular to the left-right direction. When the supported tubular portion 33E is sandwiched between the pair of support pieces 15B, the abutting portions 15B2 of the pair of support pieces 15B are in contact with each other. That is, the supported tubular portion 33E is supported from the radially outer side by the arcuate support portion 15B1 over the entire circumference.

(Effect)
In the hammer drill 10 configured as described above, when the trigger 20 is pulled, the motor 40 is driven under the control of the control section 80, and the driving force of the motor 40 is transmitted to the tip tool T by the drive mechanism section 50. . Specifically, in the drill mode of the hammer drill 10, a rotational force is imparted to the tip tool T, and in the hammer drill mode, a rotational force and an impact force are imparted to the tip tool T.

A lower end portion of a drive shaft 41 of the motor 40 is rotatably supported by a lower motor bearing 44 , and the lower motor bearing 44 is supported by the second body housing portion 15 . On the other hand, the upper end portion of the drive shaft 41 of the motor 40 is rotatably supported by an upper motor bearing 45, which is located inside the bearing housing portion 32B of the second inner housing portion 32 of the inner housing 30. and is supported by the bearing housing portion 32B. Further, the bearing cover 33 fixes the second inner housing portion 32 in a state in which the outer peripheral portion of the opening of the bearing accommodating portion 32B is closed from below, and the downward movement of the upper motor bearing 45 is prevented by the bearing. Limited by cover 33 .

Here, the bearing cover 33 is formed with a cylindrical supported tubular portion 33</b>E, and the supported tubular portion 33</b>E is arranged coaxially with the upper motor bearing 45 . A pair of support pieces 15B are formed in the outer housing 12 (the second main body housing portion 15), and the support pieces 15B support the supported tubular portion 33E from the radially outer side. That is, since the portion of the bearing cover 33 supported by the support piece 15B (supported cylindrical portion 33E) is formed in a circular shape, the entire portion of the support piece 15B supporting the supported cylindrical portion 33E is formed in an arc shape. can be formed. Specifically, the arc-shaped support portions 15B1 formed in an arc shape are formed on the pair of support pieces 15B, respectively, and the supported cylindrical portion 33E is arranged adjacent to and radially inside the arc-shaped support portions 15B1. there is More specifically, the supported cylindrical portion 33E is supported from the radially outer side over the entire circumferential direction by the arcuate support portion 15B1. In general, the dimensional accuracy of the circular (arcuate) portion is higher than the dimensional accuracy of the non-circular portion. Therefore, it is possible to improve the assembly positional accuracy of the bearing cover 33 with respect to the outer housing 12 (second main body housing portion 15), and the assembly positional accuracy of the second inner housing portion 32 fixed to the bearing cover 33 is also improved. can be higher. Moreover, as described above, the supported tubular portion 33E is supported from the radially outer side by the arc-shaped support portion 15B1 over the entire circumferential direction. For this reason, for example, compared to the case where a notch portion or the like is formed in the arcuate support portion 15B1, in the circumferential direction of the supported tubular portion 33E, the area where the arcuate support portion 15B1 supports the supported tubular portion 33E is larger. The sum of the angles can be increased. As a result, the supporting strength of the supporting piece 15B with respect to the supported cylindrical portion 33E can be increased, and the supporting strength with respect to the second inner housing portion 32 can be increased. As described above, the positional accuracy and support strength for the inner housing 30 can be improved.

Also, the upper motor bearing 45 is supported by the second main body housing portion 15 (main body housing 13 ) via the second inner housing portion 32 and the bearing cover 33 . Furthermore, as described above, the lower motor bearing 44 is supported by the second body housing portion 15 (body housing 13). That is, the upper motor bearing 45 and the lower motor bearing 44 are supported by the second body housing portion 15 . Therefore, the coaxiality of the upper motor bearing 45 and the lower motor bearing 44 that rotatably support the drive shaft 41 of the motor 40 can be increased.

A pair of left and right housing side fixed arms 32E are formed on the outer peripheral portion of the second inner housing portion 32, and a pair of left and right cover side fixed arms 33C are formed on the cover main body 33A of the bearing cover 33. there is Then, the fixing bolt 37 is inserted into the fixing hole 32F of the housing-side fixing arm 32E and screwed into the fixing cylindrical portion 33D of the cover-side fixing arm 33C, thereby fixing the housing-side fixing arm 32E to the cover-side fixing arm 33C. It is Thereby, the second inner housing portion 32 can be fixed to the bearing cover 33 in a well-balanced manner in the circumferential direction of the second inner housing portion 32 .

Furthermore, in the vertical direction, the positions of the supported cylindrical portion 33E of the bearing cover 33 and the housing-side fixed arm 32E and the cover-side fixed arm 33C are displaced. Therefore, it is possible to avoid interference between the support piece 15B that supports the supported cylindrical portion 33E from the radially outer side, the housing-side fixed arm 32E, and the cover-side fixed arm 33C. That is, it is not necessary to form a notch in the support piece 15B for avoiding interference with the housing-side fixed arm 32E and the cover-side fixed arm 33C. Thereby, the arcuate support portion 15B1 of the support piece 15B can be formed in an arcuate shape. Therefore, the support strength for the bearing cover 33 can be increased, and the support strength for the upper motor bearing 45 can be increased.

The bearing cover 33 has a cover main body 33A, and the cover main body 33A covers the outer peripheral portion of the opening of the bearing accommodating portion 32B in the second inner housing portion 32 from below. A supported tubular portion 33E of the bearing cover 33 extends downward from the cover main body 33A. As a result, the support piece 15B that supports the supported tubular portion 33E from the radially outer side can be arranged adjacent to the lower side of the cover main body 33A. Therefore, an increase in size in the vertical direction can be suppressed.

Further, the drive shaft 41 of the motor 40 has a motor-side bevel gear 41A, and the motor-side bevel gear 41A is inclined inward in the radial direction of the drive shaft 41 toward the upper side (the other side in the axial direction of the drive shaft 41). Consists of multiple gear teeth. Further, the drive shaft 41 meshes with the shaft-side bevel gear 54 of the intermediate shaft 51 of the drive mechanism portion 50 . As a result, when the motor 40 is driven, a downward thrust load (one axial side of the drive shaft 41) acts from the shaft-side bevel gear 54 of the intermediate shaft 51 to the motor-side bevel gear 41A. That is, a downward thrust load acts on the upper motor bearing 45 . Therefore, the bearing cover 33 can receive the thrust load and restrict the downward movement of the drive shaft 41 . Therefore, the state of engagement between the motor-side bevel gear 41A and the shaft-side bevel gear 54 can be favorably maintained.

A housing-side fitting portion 32</b>D is formed on the outer peripheral portion of the lower end portion of the second inner housing portion 32 . The housing-side fitting portion 32D is formed in a circular shape when viewed from below, and is formed concentrically with the bearing accommodating portion 32B. Further, the cover body 33A of the bearing cover 33 is formed with a cover-side fitting portion 33B. The cover-side fitting portion 33B is formed in a concave shape that opens upward, is formed in a circular shape when viewed from above, and is arranged coaxially with the supported cylindrical portion 33E of the bearing cover 33 . The housing-side fitting portion 32D is fitted into the cover-side fitting portion 33B from above. As a result, the coaxiality of the supported cylindrical portion 33E, the bearing accommodating portion 32B of the second inner housing portion 32, and the upper motor bearing 45 can be increased. Therefore, the positional accuracy of the upper motor bearing 45 with respect to the outer housing 12 can be effectively improved.

Also, the housing-side fitting portion 32D is fitted into the cover-side fitting portion 33B. That is, the bearing cover 33 is fitted to the second inner housing portion 32 from the radially outer side. As a result, it is possible to suppress an increase in size of the support structure S in the vertical direction. That is, as shown in FIG. 7, if the bearing cover 33 were to be fitted radially inwardly of the second inner housing portion 32, a ring-shaped rib inserted into the bearing accommodating portion 32B would be formed. is formed on the bearing cover 33 . In this case, the lower end portion of the second inner housing portion 32 extends downward as compared with the present embodiment. Therefore, the size of the support structure S in the vertical direction is increased. In contrast, in the present embodiment, as described above, the bearing cover 33 is fitted to the second inner housing portion 32 from the radial outside. Therefore, compared to the structure shown in FIG. 7, the vertical dimension of the bearing accommodating portion 32B can be reduced. Therefore, it is possible to suppress an increase in size of the support structure S in the vertical direction.

A support groove 33F that opens radially outward is formed in the supported tubular portion 33E of the bearing cover 33, and the edge of the arc-shaped support portion 15B1 of the support piece 15B of the second main body housing portion 15 is It is inserted into the support groove 33F. Thereby, the bearing cover 33 can be engaged with the second main body housing portion 15 in the vertical direction. Therefore, the assembly position accuracy of the bearing cover 33 and the second inner housing portion 32 (inner housing 30) with respect to the second main body housing portion 15 in the vertical direction can be improved.

A fixing bolt 37 is arranged close to the lower side of the first inner housing portion 31 of the inner housing 30 . That is, the fixing bolt 37 is arranged close to the lower side of the drive mechanism portion 50 housed in the first inner housing portion 31 . As a result, it is possible to suppress an increase in size of the hammer drill 10 in the vertical direction.

(Modified example of support piece 15B)
Next, a modified example of the support piece 15B will be described with reference to FIG. As shown in this figure, in the support piece 15B of the modified example, in a state in which the supported cylindrical portion 33E of the bearing cover 33 is sandwiched between the pair of support pieces 15B, the abutment portion 15B2 of the pair of support pieces 15B is in contact with the support piece 15B. The position of the butted portion 15B2 is set so that a predetermined gap G is formed therebetween. That is, the supported cylindrical portion 33E (bearing cover 33) is supported from the radially outer side by the arcuate support portion 15B1 except for a portion. Specifically, in the circumferential direction of the supported tubular portion 33E, the total angle of the region where the arc-shaped support portion 15B1 supports the supported tubular portion 33E is 270 degrees or more (340 degrees as an example in this modified example). is set to In other words, the arc-shaped support portion 15B1 is configured to support 3/4 or more of the entire circumference of the supported tubular portion 33E. Accordingly, the "supporting portion that supports the supported portion from the radially outer side" in the present invention includes the case where the supporting piece 15B supports the supported cylindrical portion 33E from the radially outer side, except for a portion of the supported cylindrical portion 33E. .

Also in the modified example of the support piece 15B, the entire arcuate support portion 15B1 is formed in an arc shape. Therefore, it is possible to improve the assembly positional accuracy of the bearing cover 33 with respect to the outer housing 12 (second main body housing portion 15), and the assembly positional accuracy of the second inner housing portion 32 fixed to the bearing cover 33 is also improved. can be higher. Also, in the modified example of the support piece 15B, as in the present embodiment, for example, compared with the case where the circular support portion 15B1 is formed with a notch portion, etc., in the circumferential direction of the supported cylindrical portion 33E, The total angle of the region where the arcuate support portion 15B1 supports the supported cylindrical portion 33E can be increased. Therefore, the supporting strength of the supporting piece 15B with respect to the supported tubular portion 33E can be increased, and the supporting strength with respect to the second inner housing portion 32 can be increased. As described above, it is possible to improve the positional accuracy and support strength with respect to the inner housing 30 even in the modified example of the support piece 15B.

10 hammer drill (work machine)
12 outer housing 15B support piece (support portion)
30 inner housing 31 first inner housing portion (first housing portion)
32 second inner housing part (second housing part)
32B bearing housing (bearing support hole)
32D housing side fitting portion 32E housing side fixed arm (fixed portion)
33 Bearing cover 33A Cover main body 33B Cover-side fitting portion 33C Cover-side fixed arm (fixed portion)
33E supported cylindrical portion (supported portion)
37 fixing bolt (fixing member)
40 motor (driving source)
41 drive shaft 41A motor side bevel gear (bevel gear)
50 Drive Mechanism (Mechanism)
51 intermediate shaft (driven shaft)
T tip tool

Claims (9)

a drive source having a drive shaft;
a mechanical portion operated by the driving force of the drive shaft;
a bearing that rotatably supports the drive shaft;
an inner housing including a first housing portion that houses the mechanism portion and a second housing portion that has a bearing support hole that supports the bearing;
a bearing cover to which the second housing part is fixed and which covers the opening of the bearing support hole;
an outer housing that accommodates the drive source, the inner housing, and the bearing cover;
with
A cylindrical supported portion arranged coaxially with the bearing is formed in the bearing cover,
The working machine, wherein the outer housing is provided with a supporting portion that supports the supported portion from the outside in a radial direction. A portion to be fixed is formed on an outer peripheral portion of the second housing portion,
The bearing cover is formed with a fixing portion for fixing the fixed portion by a fixing member,
The working machine according to claim 1, wherein positions of the supported portion, the fixed portion, and the fixed portion are shifted in the axial direction of the drive shaft. The bearing cover has a cover body that covers the bearing support hole from one axial direction side of the drive shaft,
3. The working machine according to claim 2, wherein the supported portion extends from the cover body to one side in the axial direction of the drive shaft. A housing-side fitting portion disposed coaxially with the bearing is formed on an outer peripheral portion of the second housing portion at one end in the axial direction of the drive shaft,
4. The working machine according to claim 3, wherein the cover main body is formed with a cover-side fitting portion into which the housing-side fitting portion is fitted. The working machine according to any one of claims 2 to 4, wherein the fixed portion and the fixed portion are provided at two radially outer sides of the bearing support hole. The working machine according to any one of claims 2 to 5, wherein the fixing member is arranged on one side in the axial direction of the drive shaft with respect to the mechanism portion. the mechanical portion includes a driven shaft extending in a direction intersecting the axial direction of the drive shaft;
The work machine according to any one of claims 1 to 6, wherein the drive shaft has a bevel gear fitted with the driven shaft. The bearing cover covers the bearing support hole from one side in the axial direction of the drive shaft,
8. The working machine according to claim 7, wherein the bevel gear comprises a plurality of gear teeth inclined radially inward toward the other axial side of the drive shaft. 9. The mechanism part according to claim 7 or 8, wherein the mechanical part transmits the rotary motion of the driven shaft to the tip tool, converts the rotary motion of the driven shaft into reciprocating motion, and imparts an impact force to the tip tool. working machine.

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