JP6278816B2 - Handheld electric grinder - Google Patents

Description

  The present invention relates to a hand-held electric grinder, and more particularly to a hand-held electric grinder including a gear case that houses a driving force transmission unit for transmitting a rotational driving force of a driving source to a tip tool.

  Generally, a hand-held electric grinder is a motor that serves as a drive source, a housing in which a grip portion is formed and that houses the motor, a metal gear case connected to the front side of the housing, and a downward projecting from the gear case. A spindle and a rotary tool attached to the lower end of the spindle are provided. The gear case accommodates a drive transmission unit including a gear or the like for transmitting rotation of the rotation shaft of the motor to the spindle. Further, as the rotary tool, a grindstone, a cutter, or the like is used, and processing operations such as grinding and cutting can be performed on metal, concrete, and the like by rotation of the rotary tool (for example, see Patent Documents 1 and 2 below). . When such a hand-held electric grinder is operated for a long time, the gear case becomes hot due to the heat generated by the meshing of the gears in the drive transmission unit or the heat from the rotating tool heated by the machining operation, When the user touched it, it was uncomfortable. As a countermeasure, it is conceivable to cover a metal gear case with a resin gear case cover.

  In Patent Document 3 below, a gear case cover (cover) that covers the gear case is configured to be detachably mounted using an air window (ventilation opening) formed in the housing. An invention relating to an electric tool that achieves ease and stability of the mounted state is described.

JP 2011-83848 A JP 2002-66897 A Japanese Patent No. 4396447

  However, it is not easy to adopt the specific configuration described in Patent Document 3 described above in the hand-held electric grinder due to the difference in the structure of the electric tool, and therefore, a new gear suitable for the hand-held electric grinder. It was necessary to devise a case cover mounting form.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a hand-held electric grinder that realizes easy attachment / detachment of the gear case cover and stability of the attached state. .

  A hand-held electric grinder according to the present invention includes a motor having a rotating shaft, a housing in which a grip portion is formed and housing the motor, and a metal gear screwed to the front side of the housing by a plurality of screws from the front. A case, a spindle having an axis that projects downward from the gear case and intersects the axis of the rotary shaft, a drive transmission unit that is housed in the gear case and transmits the rotation of the rotary shaft to the spindle, and a lower end of the spindle A rotating tool attached to a portion, and a gear case cover made of resin that covers the gear case from above can be attached to the gear case, and a locked portion is formed on the gear case. The gear case cover is formed with a locking portion for locking to the locked portion and a hole or groove through which the screw is inserted. The gear case cover is configured to be attached to the gear case by using both locking of the locking portion to the locked portion and screwing with the screw. To do.

The hand-held electric grinder according to the present invention includes a motor having a rotation shaft, a housing in which a grip portion is formed and housing the motor, a metal gear case connected to the front side of the housing, and the gear case A spindle having an axis that protrudes downward from the axis and intersects the axis of the rotation axis, a drive transmission unit that is housed in the gear case and transmits the rotation of the rotation axis to the spindle, and a rotary tool that is attached to the lower end of the spindle The gear case can be mounted with a resin gear case cover that covers the gear case from above, and the gear case has a plurality of locked portions, and the gear The case cover has a plurality of locking portions that are respectively locked to the plurality of locked portions, and the gear case cover is attached to the gear case. Chakuji, the plurality of at least one portion of the engaging portion is shifted from the unlocked state by the elastically deformed locking state is configured to lock, the engaged portion is spaced in a side view 3 It is formed in the place, The line which connects three places forms the triangle, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the handheld electric grinder which implement | achieved the ease of attachment or detachment of a gear case cover, and stability of the mounting state can be provided.

It is the figure which looked at the handheld electric grinder which concerns on 1st embodiment of this invention from upper direction. It is the figure which looked at the handheld electric grinder which concerns on 1st embodiment of this invention from the right side. It is the figure which looked at the handheld electric grinder which concerns on 1st embodiment of this invention from the front. It is a figure which shows the principal part of the AA cross section in FIG. It is a figure which shows the principal part of the BB cross section in FIG. It is a figure which shows the principal part of CC cross section in FIG. It is a figure which shows the DD cross section in FIG. It is the principal part of the figure which looked at the handheld electric grinder which concerns on 1st embodiment of this invention from the right side, and has shown the case where a gear case cover is used without mounting | wearing. It is a principal part of the figure which looked at the handheld electric grinder which concerns on 2nd embodiment of this invention from upper direction. It is the principal part of the figure which looked at the handheld electric grinder which concerns on 2nd embodiment of this invention from the right side. It is the figure which looked at the handheld electric grinder which concerns on 2nd embodiment of this invention from the front. It is a figure which shows the principal part of the EE cross section in FIG. It is a figure which shows the principal part of the FF cross section in FIG. It is the principal part of the figure which looked at the handheld electric grinder which concerns on 2nd embodiment of this invention from the right side, and has shown the case where a gear case cover is used without mounting | wearing.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  First, the basic structure of the hand-held electric grinder according to the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a view of a hand-held electric grinder according to a first embodiment of the present invention as viewed from above. FIG. 2 is a right hand view of the hand-held electric grinder according to the first embodiment of the present invention. FIG. 3 is a front view of the hand-held electric grinder according to the first embodiment of the present invention. FIG. 4 is a view showing a main part of the AA cross section in FIG. FIG. 5 is a view showing the main part of the BB cross section in FIG. Further, in the present specification, as shown in the drawing, “front, rear, left, right, upper, lower” are defined and described.

  As shown in FIGS. 1 to 5, a hand-held electric grinder 10 according to a first embodiment of the present invention includes a housing 11 formed in a substantially cylindrical shape so that an operator can hold it, and a housing 11 is provided with a gear case 13 arranged on the front side of 11 and a disk-shaped grindstone 21 as a rotary tool arranged below the gear case 13.

  The housing 11 includes a motor case 12 serving as a casing that houses a main portion of the motor 31 serving as a driving source, and a power cord and a switch that are disposed behind the motor case 12 and supply power to the motor 31. A tail cover 14 serving as a cover member in which a power supply device such as the above is housed is formed as a main constituent member. The gear case 13 is connected to the front side of the motor case 12 by four screws 17a, 17b, 17c, and 17d that are screwed in from the front with an inner case 16 interposed therebetween. A driving force transmission unit 20 including a plurality of bevel gears for transmitting the rotational driving force to the grindstone 21 is housed.

  The motor case 12 is formed in a cylindrical shape from a metal such as resin or aluminum alloy, and the outer periphery thereof is formed as a grip portion 12a that is gripped by the user. The grip portion 12a is formed in a substantially cylindrical shape so that the user can easily grip it, and the surface thereof is provided with an uneven shape for preventing slipping.

  The gear case 13 is formed of a metal member such as an aluminum alloy. The rear of the gear case 13 is open, and an inner case 16 is installed on the opening side. The gear case 13 has a lid member 13a screwed to the lower portion thereof, and a safety cover 22 that covers about half of the grindstone 21 from above and behind is installed at the lower portion of the lid member 13a. The safety cover 22 is equipped for the purpose of preventing scattering of chips generated by processing the grindstone 21 to the user side.

  Housed in the motor case 12 is a main part of a motor 31 that is a drive source for driving the grindstone 21. The motor 31 includes a motor shaft 32 that is a rotating shaft, and a front end portion of the motor shaft 32 protrudes into the gear case 13. The drive transmission unit 20 includes a small bevel gear 23 fixed to the front end portion of the motor shaft 32, a spindle 27 disposed orthogonal to the motor shaft 32, and bearings 25 and 26 that rotatably support the spindle 27. And a large bevel gear 24 fixed to the spindle 27 and meshing with the small bevel gear 23. By this drive transmission unit 20, the rotational drive of the motor shaft 32 is decelerated and transmitted to the spindle 27. In the present embodiment, the spindle 27 is arranged orthogonal to the motor shaft 32. However, it is possible to adopt a crossing angle other than orthogonal by appropriately changing the specifications of the bevel gear.

  A lower end portion of the spindle 27 protrudes downward from the lid member 13a, and a grindstone 21 as a rotary tool is attached thereto by a rotary tool fixing portion. The rotary tool fixing portion 28 includes a holder 28a that is inserted in the lower end portion of the spindle 27 so as not to be relatively rotatable, and a nut 28b that is screwed into a male screw formed on the lower end portion of the spindle 27 below the holder 28a. Then, the grindstone 21 is sandwiched between the holder 28a and the nut 28b by screwing the nut 28b, whereby the grindstone 21 is attached to the spindle 27. When the grindstone 21 is attached, the spindle lock mechanism 29 shown in FIG. 5 or the like is operated to prevent the spindle 27 from being rotated by tightening the nut 28b. The spindle lock mechanism 29 is conventionally known and will not be described in detail.

  A cooling fan 19 that generates cooling air for cooling the motor 31 is fixed to the motor shaft 32 behind the inner case 16. The cooling fan 19 is rotated by the operation of the motor 31, so that outside air is taken in from an opening formed in the rear portion of the housing 11, cools the motor 31, and then the plurality of wind windows 18 formed on the front surface of the gear case 13. It is discharged from the outside.

  The basic structure of the handheld electric grinder 10 according to the first embodiment of the present invention has been described above. Next, in addition to the reference diagrams of FIGS. 6 to 8, characteristic portions of the hand-held electric grinder 10 according to the first embodiment of the present invention will be described.

  Here, FIG. 6 is a view showing the main part of the CC cross section in FIG. FIG. 7 is a view showing a DD cross section in FIG. FIG. 8 is a main part of a view of the hand-held electric grinder according to the first embodiment of the present invention as viewed from the right side, and shows a case where the gear case cover is not used.

  The hand-held electric grinder 10 according to the first embodiment of the present invention is provided with a resin gear case cover 41 that covers the gear case 13 from above. The hand-held electric grinder 10 of this embodiment can be used even when the gear case cover 41 shown in FIG. 8 is not attached. The gear case cover 41 is attached to the gear case 13, and the shape thereof is formed as a shape along the outline of the gear case 13. The gear case cover 41 has an opening 44 communicating with the wind window 18 at a location adjacent to the front side of the wind window 18 of the gear case 13.

  The gear case cover 41 covers the gear case 13 and is screwed by inserting screws 17a and 17b from the front into screw insertion holes 42a and 42b with countersinks formed on the upper left and right sides of the gear case cover 41. In addition, as well shown in FIG. 7, the latched portions 13 b and 13 b formed on the left and right sides of the gear case 13 are substantially L-shaped in cross-section formed on the left and right sides of the lower portion of the gear case cover 41. The locking portions 43 and 43 are locked to be attached to the gear case 13. As shown in FIG. 8, the screws 17 a and 17 b to which the gear case cover 41 is screwed are used when the handheld electric grinder 10 is used without the gear case cover 41 being attached. Among the four screws 17a, 17b, 17c, and 17d that are used to connect to the two, two screws are located on the upper side. Further, the locked portions 13 b and 13 b are lower edges of the hanging wall that forms the side surface of the gear case 13. In the present embodiment, the screw insertion holes 42a and 42b are employed for screwing the screws 17a and 17b. However, they may be formed as screw insertion grooves.

  Thus, in this embodiment, the gear case cover 41 is attached to the gear case 13 by screwing with the screws 17a and 17b and locking the locking portions 43 and 43 to the locked portions 13b and 13b. Since it is executed in combination, it can be easily mounted and a stable mounting state can be maintained.

  Further, since the gear case cover 41 is screwed using two screws 17a and 17b which are part of the four screws 17a, 17b, 17c and 17d, when the gear case cover 41 is attached and detached, The remaining two screws 17c and 17d maintain a state in which the gear case 13 is screwed to the housing 11. Therefore, the state described below does not occur when the gear case cover 41 is attached or detached. In other words, when a configuration is adopted in which the gear case cover 41 is screwed using all four screws (screws 17a, 17b, 17c, 17d), all four screws are removed when the gear case cover 41 is attached or detached. A state in which the screws (screws 17a, 17b, 17c, 17d) are removed occurs. This state is an unstable state in which the drive transmission unit 20 except the gear case 13 and the small bevel gear 23 which is a member supported by the gear case 13 can be detached from the housing 11. In the present embodiment, the occurrence of such an unstable state can be avoided, so that the possibility of a malfunction in the attaching / detaching operation of the gear case cover 41 can be eliminated.

  Moreover, since the gear case cover 41 is formed as a shape along the outer shape of the gear case 13, it is possible to suppress an increase in the size of the device. Furthermore, in the cutting work by the grindstone 21, it is possible to suppress the maximum cutting depth from being reduced due to the mounting of the gear case cover 41.

  The handheld electric grinder according to the first embodiment of the present invention has been described above. Next, with reference to FIGS. 9-14, the handheld electric grinder which concerns on 2nd embodiment of this invention is demonstrated. Since the basic structure of the hand-held electric grinder according to the second embodiment of the present invention is the same structure as the hand-held electric grinder according to the first embodiment, the following description will focus on the characteristic part. Do. Moreover, the same code | symbol is attached | subjected about the same member as the handheld electric grinder which concerns on 1st embodiment, and detailed description is abbreviate | omitted.

  Here, FIG. 9 is a main part of a view of the hand-held electric grinder according to the second embodiment of the present invention as viewed from above. FIG. 10 is a main part of a view of the hand-held electric grinder according to the second embodiment of the present invention as viewed from the right side. FIG. 11 is a front view of a hand-held electric grinder according to the second embodiment of the present invention. FIG. 12 is a view showing the main part of the EE cross section in FIG. FIG. 13 is a view showing the main part of the FF cross section in FIG. FIG. 14 is a main part of a view of the hand-held electric grinder according to the second embodiment of the present invention as viewed from the right side, and shows a case where the gear case cover is not used. Further, in the present specification, as shown in the drawing, “front, rear, left, right, upper, lower” are defined and described.

  A hand-held electric grinder 100 according to the second embodiment of the present invention includes a gear case 113 formed of a metal member such as an aluminum alloy. The gear case 113 has a lid member 113a screwed to the lower portion thereof. The gear case 113 is provided with a resin gear case cover 141 that covers the gear case 113 from above. The handheld electric grinder of this embodiment can be used even when the gear case cover 141 shown in FIG. 14 is not attached. The shape of the gear case cover 141 is formed along the outer shape of the gear case 113, and an opening 144 communicating with the wind window 118 is formed at a location adjacent to the front side of the wind window 118 of the gear case 113. . The gear case cover 141 covers and hides two screws 17a, 17b located on the upper side among the four screws 17a, 17b, 17c, 17d for connecting the gear case 113 to the motor case 12.

  The mounting of the gear case cover 141 to the gear case 113 is performed by locking the plurality of locking portions formed on the gear case cover 141 to the plurality of locked portions formed on the gear case 113, respectively. . The details will be described below.

  Upper convex shapes 113b and 113b are formed on the upper left and right sides of the rear end portion of the gear case 113, and lower convex shapes 113c and 113c are formed on the lower left and right sides. The gear case cover 141 is formed with upper locking portions 143b and 143b and lower locking portions 143c and 143c that are locked to the upper convex shapes 113b and 113b and the lower convex shapes 113c and 113c, respectively. As shown in FIG. 13, the upper locking portions 143b and 143b and the lower locking portions 143c and 143c are formed in a substantially L shape in cross section. As shown in FIG. 12, a front side locking portion 143 d that locks to the collar portion at the front end of the lid member 113 a is formed in a substantially L shape in cross section at the lower front end of the gear case cover 141. The upper locking portions 143b and 143b, the lower locking portions 143c and 143c, and the front locking portion 143d are the upper protruding shapes 113b and 113b, the lower protruding shapes 113c and 113c, and the front ends of the lid member 113a, which are the locked portions. The gear case cover 141 is attached to the gear case 113 by being respectively engaged with the collar portion. Moreover, these to-be-latched parts are formed in three places spaced apart in a side view, and the line connecting these three places forms a triangle.

  Next, an operation for attaching the gear case cover 141 to the gear case 113 will be described. The operation of attaching the gear case cover 141 to the gear case 113 is performed by first bringing the gear case cover 141 close to the gear case 113 from above and locking the upper locking portions 143b and 143b to the upper convex shapes 113b and 113b. At this time, the front portion of the gear case cover 141 is spaced upward from the gear case 113. That is, it is in a state of rotating about 30 degrees counterclockwise around the upper convex shapes 113b and 113b with respect to the mounting state shown in FIG. Next, the gear case cover 143 is rotated clockwise about the locked upper convex shapes 113b and 113b. By this rotation, the front side locking portion 143d is locked to the flange at the front end of the lid member 113a, and at the same time, the lower side locking portions 143c and 143c are respectively avoiding the lower convex shapes 113c and 113c by elastic deformation. After passing, it is locked to the lower convex shapes 113c and 113c by elastic restoring force. The elastic deformation of the lower locking portions 143c and 143c is performed by a mode in which an operator operates the lower locking portions 143c and 143c to elastically deform the lower locking portions as the gear case cover 143 rotates. There is a form in which 143c and 143c are pressed and elastically deformed by sliding contact with a guide surface formed adjacent to the lower convex shapes 113c and 113c. In the present embodiment, the former case is illustrated.

  Thus, in the handheld electric grinder 100 according to the second embodiment of the present invention, the upper locking portions 143b and 143b, the lower locking portions 143c and 143c, and the front locking portion 143d are the locked portions. The upper convex shapes 113b and 113b, the lower convex shapes 113c and 113c, and the front edge of the lid member 113a are respectively locked, and the lower locking portions 143c and 143c are locked by elastic restoring force. Therefore, it can be easily mounted and a stable mounting state can be maintained.

  Moreover, in the hand-held electric grinder 100 according to the second embodiment of the present invention, the locked portions are formed at three locations separated in a side view, and a line connecting these three locations forms a triangle. As a result, a more stable wearing state can be realized.

  As mentioned above, although preferred embodiment of this invention was described, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the embodiment.

  For example, in the second embodiment of the present invention described above, the upper locking portions 143b and 143b, the lower locking portions 143c and 143c, and the front locking portion are used to mount the gear case cover 141 to the gear case 113. 143d is configured to be locked to the locked portions. For example, when a suitable mounting state can be obtained by locking the upper locking portions 143b and 143b and the lower locking portions 143c and 143c, A configuration in which the locking portion 143d is not locked to the locked portion (the front edge of the lid member 113a), that is, a configuration in which the front locking portion 143d is not formed may be employed.

  Further, for example, the above-described second embodiment can be improved to further stabilize the mounting state of the gear case cover 141. That is, in the second embodiment described above, the lower locking portions 143c and 143c pass while avoiding the lower convex shapes 113c and 113c by elastic deformation, respectively, and then the lower convex shapes 113c by elastic restoring force. , 113c so that when the gear case cover 141 is removed, the lower locking portions 143c, 143c are elastically deformed to release the locked state to the lower convex shapes 113c, 113c. Is required. In view of this, the elastic deformation of the lower locking portions 143c and 143c is configured to be regulated by the upper surface of the safety cover 22 being in contact with each other. It is possible to prevent the locked state from being released. With this configuration, it is possible to effectively prevent the gear case cover 141 from falling off. When this configuration is adopted, when the gear case cover 141 is attached to the gear case 113, it is necessary to remove the safety cover 22 in advance.

  10 hand-held electric grinder, 11 housing, 12 motor case, 12a gripping part, 13 gear case, 13a lid member, 13b locked part, 14 tail cover, 16 inner case, 16a inner case side circumferential uneven part, 17 front Bearing, 17a-17d screw, 18 air window, 19 cooling fan, 20 drive transmission, 21 grinding wheel, 22 safety cover, 23 small bevel gear, 24 large bevel gear, 25 bearing, 26 bearing, 27 spindle, 28 rotating tool fixing Part, 28a holder, 28b fixing nut, 29 spindle lock mechanism, 31 motor, 32 motor shaft, 41 gear case cover, 42a screw insertion hole, 42b screw insertion hole, 43 locking part, 44 opening, 100 handheld electric grinder, 113 Gear case, 113a Lid member 113b upper convex 113c lower convex 118 air windows, 141 the gear case cover, 143b upper engaging portion, 143c lower locking portion, 143d front engaging portion, 144 opening

Claims (2)

A motor having a rotating shaft; a housing in which a grip portion is formed; and a housing that houses the motor; a metal gear case that is screwed to the front side of the housing by a plurality of screws from the front; A spindle having an axis that intersects the axis of the rotary shaft; a drive transmission unit that is housed in the gear case and transmits the rotation of the rotary shaft to the spindle; and a rotary tool attached to the lower end of the spindle. In hand-held electric grinder,
The gear case can be fitted with a resin gear case cover that covers the gear case from above,
A locked portion is formed in the gear case,
The gear case cover is formed with a locking portion that is locked to the locked portion and a hole or groove through which the screw is inserted,
The gear case cover is configured to be attached to the gear case by using both locking of the locking portion to the locked portion and screwing with the screw. Hand-held electric grinder. A motor having a rotating shaft; a housing in which a grip portion is formed and housing the motor; a metal gear case connected to the front side of the housing; and a downward projecting from the gear case that intersects the axis of the rotating shaft In a hand-held electric grinder comprising: a spindle having an axis; a drive transmission unit that is housed in the gear case and transmits rotation of the rotary shaft to the spindle; and a rotary tool attached to a lower end of the spindle.
The gear case can be fitted with a resin gear case cover that covers the gear case from above,
A plurality of locked portions are formed in the gear case,
The gear case cover is formed with a plurality of locking portions that are respectively locked to the plurality of locked portions,
At the time of mounting the gear case cover to the gear case, it is configured to shift and lock at least one of the plurality of locking portions from the non-locking state to the locking state by elastic deformation ,
The said to-be-latched part is formed in three places spaced apart by the side view, The line which connects three places forms the triangle, The handheld electric grinder characterized by the above-mentioned.

Images