JP6223848B2 - Impact tool - Google Patents

Description

  The present invention relates to an impact tool such as a hammer drill or an electric hammer.

  For example, in a hammer drill, a crank housing that houses a crank mechanism that converts the rotation of a motor into a reciprocating motion of a piston or the like is fixed above a motor housing that houses a motor by screws that are screwed from above. There is known one in which a handle is screwed from the rear to the rear of the housing (see Non-Patent Document 1).

Makita General Catalog 2013-10, Hammer Drill HR5211C, [Search January 24, 2014], Internet <http://www.makita.co.jp/product/ecatalog/sougou/index.html#44>

  In such a hammer drill, the screw for fixing the motor housing and the crank housing is hidden by a plurality of housings and covers such as handles, so that when repairing the motor, the worker must Each of the fixing screws is loosened to remove the housing and the like, and then the screw for fixing the motor housing and the crank housing is loosened to separate the motor housing.

  Therefore, the present invention has an object of providing a striking tool that can easily remove a screw that connects a motor housing and an upper housing such as a crank housing and improve workability related to repair or the like. is there.

In order to achieve the above object, according to a first aspect of the present invention, a housing includes a motor housing that houses a motor, and an upper housing that houses a forward-facing output portion at the top of the motor housing. An impact tool in which a housing and an upper housing are connected by a plurality of screws respectively arranged at the front and rear of the motor housing, and the screw located on the front side of the motor housing among the screws is from the lower side to the rear side of the motor housing Screws located on the rear side of the motor housing are screwed onto the rear side of the motor housing and the upper housing, and the handle housing covering the screw located on the rear side of the motor housing is fixed with screws. The screw is exposed .
The “screw” in the present invention includes a “bolt”.
In order to achieve the above object, according to a second aspect of the present invention, the housing includes a motor housing that houses a motor, and an upper housing that houses a forward-facing output portion at the top of the motor housing. An impact tool in which a housing and an upper housing are connected by a plurality of screws respectively arranged at the front and rear of the motor housing, and the screw located on the front side of the motor housing among the screws is from the lower side to the rear side of the motor housing The screws located at the top are respectively screwed together from above, and the front cover for covering the screws located on the front side of the motor housing is assembled to the front portion of the motor housing .
According to a third aspect of the present invention, in the configuration of the second aspect , the front cover is fixed by a belt-like member that is wound around the front cover from the front and attached to the housing.
According to a fourth aspect of the present invention, in the configuration of the second or third aspect , an engaging portion that engages with each other at an assembly position of the front cover is provided between the upper housing and the front cover. Is.

According to the first and second aspects of the present invention, the motor housing and the upper housing are connected without removing the fixing screws such as a plurality of housings by screwing the front screws of the motor housing from below. The front and rear screws can be easily removed, and the workability related to repair and the like can be improved.
In particular, according to the first aspect of the invention, in addition to the above effects , the handle housing normally protects the rear screw, while the handle housing can be easily removed by removing the handle housing. .
In particular, according to the second aspect of the present invention, in addition to the above-described effect , the front cover is normally protected by the front cover, while the screw can be easily removed by removing the front cover.
According to the third aspect of the invention, in addition to the effect of the second aspect , the front cover can be easily fixed using the belt-like member.
According to the invention described in claim 4 , in addition to the effect of claim 2 or 3 , it is possible to prevent the front cover from falling off when the front covers are assembled by engagement between the engaging portions, and the workability related to the assembly of the front cover is improved. improves.

It is a general view of a hammer drill. It is a longitudinal cross-sectional view of a hammer drill. It is a perspective view in the state where a motor housing was separated (a handle housing is omitted). It is a side view of the state which separated the motor housing (a handle housing is omitted) It is a perspective view in the state where a handle housing was separated. It is a side view in the state where a handle housing was separated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall view of a hammer drill as an example of an impact tool, FIG. 2 is a longitudinal sectional view, and the hammer drill 1 has an output shaft 4 at the rear of the housing 2 (the left side of FIGS. 1 and 2 is the front). An upward motor 3 is arranged, a crank mechanism 5 and a rotation transmission mechanism 6 are provided above the motor 3, and an output portion 7 having a tool holder 8 to which a bit (not shown) can be attached is provided at the front end to rotate the output shaft 4. Accordingly, the hitting or hitting + rotation is transmitted to the bit via the crank mechanism 5 and the rotation transmission mechanism 6. A handle 9 having a switch 10 and a switch lever 11 is provided behind the housing 2. Reference numeral 12 denotes a power cord.

  The housing 2 here is connected to the motor housing 20 that houses the motor 3, the upper end of the motor housing 20, and supports the output shaft 4, the crank shaft 13 of the crank mechanism 5, and the intermediate shaft 14 of the rotation transmission mechanism 6. A gear housing 21 connected to the upper side of the gear housing 21, a crank housing 22 serving as an upper housing for accommodating the crank mechanism 5, the rotation transmission mechanism 6, and the rear portion of the output unit 7, and a front side of the crank housing 22. The front housing 23 accommodates the front portion of the output portion 7 and the handle housing 24 connected to the motor housing 20 and the crank housing 22 to form the handle 9 at the rear end. A gear housing cover 25 as a front cover that covers the front portion of the gear housing 21 is provided at the upper end of the motor housing 20, and a housing cover 26 and a crank cap cover 27 are provided outside the crank housing 22 and the front housing 23. It has been.

The output shaft 4 of the motor 3 protrudes into the crank housing 22 through the gear housing 21 and meshes with an upper gear 15 provided on the crankshaft 13. An eccentric shaft 16 provided on the crankshaft 13 is connected to a piston 18 accommodated in a cylinder 17 held by a crank housing 22 so as to be able to move back and forth via a connecting rod 19, and the rotation of the crankshaft 13 is controlled by a piston. Conversion to 18 reciprocations is possible. A striking element 31 is accommodated in the cylinder 17 in front of the piston 18 via an air chamber 30, and an intermediate element 32 is accommodated in the tool holder 8 in front of the striking element 31. A chuck 33 for inserting and attaching a bit is provided at the front end of the tool holder 8 in front of the intermediate element 32.
On the other hand, the lower gear 34 provided on the crankshaft 13 meshes with an intermediate gear 35 provided with a torque limiter provided on the intermediate shaft 14 in front thereof, and the first bevel gear 36 provided on the upper end of the intermediate shaft 14 is The rear end of the tool holder 8 meshes with a second bevel gear 37 that is rotatably mounted.

  In front of the second bevel gear 37, the tool holder 8 is provided with a ring-shaped clutch 38 that is splined with the tool holder 8, and a lock ring 39 that is integral with the tool holder 8 is provided in front of the clutch 38. The clutch 38 is slidable between a retracted position that engages with the second bevel gear 37 and an advanced position that engages with the lock ring 39. That is, if the clutch 38 is in the retracted position, the rotation of the second bevel gear 37 can be transmitted to the tool holder 8 via the clutch 38, and if the clutch 38 is in the advanced position, the rotation of the second bevel gear 37 is rotated in the tool holder 8. However, the rotation of the tool holder 8 is locked via the lock ring 39. Since the tool holder 8 is free to rotate when the clutch 38 is positioned between the second bevel gear 37 and the lock ring 39, an arbitrary rotation angle can be selected. The front and rear and intermediate positions of the clutch 38 can be selected by rotating the change lever 40 provided on the upper surface of the crank cap cover 27.

  Therefore, when the switch lever 11 is pushed in and the switch 10 is turned on, the motor 3 is driven to rotate the output shaft 4 and rotate the crankshaft 13 via the upper gear 15, so that the eccentric shaft 16 moves eccentrically. Then, the piston 18 reciprocates through the connecting rod 19. Then, the striker 31 moves back and forth in conjunction with the action of the air spring, strikes the intermediate piece 32 and transmits the strike to the bit at the front end of the tool holder 8. At the same time, the intermediate shaft 14 is rotated via the lower gear 34 and the intermediate gear 35 of the crankshaft 13 and the second bevel gear 37 is rotated. At this time, if the clutch 38 is switched to the retracted position, the rotation of the second bevel gear 37 is transmitted to the tool holder 8 via the clutch 38, and the bit performs a rotating operation in addition to the impact (hammer drill mode). On the contrary, if the clutch 38 is switched to the forward position, the rotation of the second bevel gear 37 is not transmitted to the tool holder 8, so that the hammer mode in which only the impact is transmitted to the bit. A controller 41 for adjusting the energization amount of the motor 3 is disposed behind the motor 3. By operating an adjustment dial 42 provided on the controller 41 and exposed on the side surface of the motor housing 20, the number of rotations and the number of hits can be adjusted. Adjustment is possible.

  A ring-shaped concave groove 43 is provided around the inner periphery of the clutch 38, and a plurality of through holes 44, 44,... Communicating with the concave groove 43 are formed in the clutch 38 in the radial direction. . On the other hand, the tool holder 8 is formed with communication holes 45, 45... Communicating with the concave grooves 43 at the front and rear positions of the clutch 38. Therefore, the air in the tool holder 8 whose temperature has risen due to the striking operation or the like can escape from the communication hole 45 to the outside of the output portion 7 through the concave groove 43 and the through hole 44 of the clutch 38 in either operation mode.

  As shown in FIGS. 3 and 4, the motor housing 20 and the crank housing 22 are connected to each other by fixing the motor housing 20 to the upper crank housing 22 with a plurality of bolts via the gear housing 21. However, here, at the rear part of the motor housing 20, a pair of left and right bolts 46, 46 are screwed into the motor housing 20 from above the crank housing 22 through both ends of the rear part of the crank housing 22 and both ends of the rear part of the gear housing 21. In the front part of the motor housing 20, a pair of left and right bolts 47, 47 are similarly screwed into the crank housing 22 from the lower side of the gear housing 21 through the both ends of the front part of the motor housing 20 and both ends of the middle part of the gear housing 21. It is like that. Positioning bosses 48, 48... That fit into recesses (not shown) provided on the lower surface of the crank housing 22 are provided in the through portions of the bolts 46, 47 on the upper surface of the gear housing 21.

Further, the gear housing 21 has a front portion that pivotally supports the intermediate shaft 14 protruding forward from the motor housing 20, and both ends of the front portion also penetrate the gear housing 21 from the lower side of the gear housing 21 to form a crank housing. The crank housing 22 is connected by a pair of left and right bolts 49, 49 that are screwed into the 22.
The front portion of the gear housing 21 is covered with a gear housing cover 25 as a front cover assembled to the upper front end of the motor housing 20. As shown in FIG. 5, the gear housing cover 25 has a dish shape with the upper surface and the rear surface open, and a protrusion 50 protruding from the center of the inner surface of the front end has an engagement piece protruding from the center of the front end of the crank housing 22. A groove 51 that can be engaged with 52 is formed, and insertion portions 53 and 53 are formed in the rear portions of both ends so as to enter inside the left and right upper ends of the motor housing 20 in the assembled state.

  Therefore, when the gear housing cover 25 is slid rearward so that the insertion portions 53 and 53 are inserted inside the left and right upper ends of the motor housing 20 from the front of the motor housing 20 with the groove 51 aligned with the engagement piece 52, As shown in FIG. 2, the gear housing cover 25 is continuous with the motor housing 20 with the engaging piece 52 engaged with the groove 51 and the insertion portions 53, 53 engaged with the upper left and right ends of the motor housing 20. As a result, the front portion of the gear housing 21 is covered. In this state, the front bolts 47 and 47 for assembling the motor housing 20 and the bolts 49 and 49 for assembling the gear housing 21 are covered with the gear housing cover 25.

  On the other hand, the handle housing 24 has a cover portion 28 covering the rear portions of the motor housing 20 and the crank housing 22 at the front portion, and has a handle 9 formed at the rear portion. As shown in FIGS. Are assembled to the rear portions of the motor housing 20 and the crank housing 22, and the bosses 54, 54,... Formed forward in the cover portion 28 are respectively formed on the bosses 55, 55,. The handle housing 24 is connected to the motor housing 20 and the crank housing 22 by fitting and screwing eight screws 56, 56... From the rear at the positions of the bosses 54, 55. In this connected state, the upper side of the cover portion 28 continues to the housing cover 26 and the crank cap cover 27, and the lower side of the cover portion 28 continues to the motor housing 20. The rear portion of the gear housing 21 is also covered with the cover portion 28 so that the bolts 46 and 46 are hidden.

  Further, the outer periphery of the upper end of the gear housing cover 25, the left and right side surfaces at the upper end of the motor housing 20, and the outer periphery of the cover portion 28 of the handle housing 24 are continuously formed in the assembled state of the gear housing cover 25 and the handle housing 24. Recessed portions 57, 57,... Are respectively formed, and a belt-like cover 29 as a belt-like member is provided over the entire circumference of these concave portions 57. That is, the belt-like cover 29 is wound around the front of the gear housing cover 25 at the position of the concave portion 57, and the small bosses 58, 58 projecting from the inner surface of the rear end of the belt-like cover 29 are formed in the concave portion 57 of the cover portion 28. The belt-shaped cover 29 is fitted into the boss 54 provided at the position of FIG. 1, and two of the screws 56 for assembling the handle housing 24 are screwed together with the belt-shaped cover 29, so that the belt-shaped cover 29 is connected to the gear housing cover 25 and the motor as shown in FIG. The housing 20 and the handle housing 24 are assembled so as to go around the cover portion 28, and in this state, the gear housing cover 25 is prevented from coming off forward.

  In the hammer drill 1 configured as described above, when the motor 3 is repaired, for example, when the handle housing 24 is removed by loosening the eight screws 56 to which the handle housing 24 is assembled, the fixing of the belt-shaped cover 29 is released. Therefore, the gear housing cover 25 that has been prevented from being detached from the belt-shaped cover 29 together with the belt-shaped cover 29 can be removed. Then, as shown in FIGS. 5 and 6, the rear bolts 46, 46 to which the motor housing 20 is assembled and the front bolts 47, 47 are exposed. If these bolts 46, 47 are loosened, the motor housing 20 Can be removed from the crank housing 22 and the gear housing 21, and the motor 3 can be repaired. In the assembly after the repair, the motor housing 20 and the crank housing 22 are connected by the bolts 46 and 47 in the reverse procedure, and then the belt housing 29 is wound by assembling the gear housing cover 25 and the handle housing 24. Then, the screw 56 may be tightened.

Thus, according to the hammer drill 1 of the said form, the volt | bolts 47 and 47 located in the front side of the motor housing 20 among the volt | bolts which connect the motor housing 20 and the crank housing 22 are the rear side of the motor housing 20 from the downward direction. Since the bolts 46 and 46 positioned at the top are screwed from above, the front and rear bolts 46 and 47 can be easily removed simply by removing the screws 56 for fixing the handle housing 24. It is possible to improve workability according to the above.
In particular, here, the handle housing 24 covering the rear bolts 46 and 46 is fixed to the rear of the motor housing 20 and the crank housing 22 by screws, and the bolts 46 and 46 are exposed when the handle housing 24 is removed. Therefore, while the bolts 46 and 46 are protected in the normal state, the bolts 46 and 46 can be easily removed by removing the handle housing 24.

Further, the gear housing cover 25 that covers the front bolts 47, 47 is assembled to the front portion of the motor housing 20, so that the bolts 47, 47 are protected in a normal state, while the bolts 47, 47 are removed by removing the gear housing cover 25. 47 can be easily removed.
Further, the gear housing cover 25 is fixed by a belt-like cover 29 that is wound around the gear housing cover 25 from the front and attached to the handle housing 24, so that the gear housing cover 25 can be easily fixed using the belt-like cover 29. Yes.
In addition, an engagement portion (groove 51, engagement piece 52) that engages with each other at the assembly position of the gear housing cover 25 is provided between the crank housing 22 and the gear housing cover 25. Since the gear housing cover 25 can be prevented from falling off when the gear housing cover 25 is assembled, the workability associated with the assembly of the gear housing cover 25 is improved.

The number of bolts for connecting the motor housing is not limited to two at the front and rear, but may be three or more, or the number may be changed at the front and rear. The number of screws for fixing the handle housing can also be changed.
Also, the front cover is not limited to the form of the gear housing cover, and the groove and the engagement piece may be provided opposite to each other. It may be adopted. Furthermore, the gear housing cover may be formed integrally with the motor housing. In this case, the bolt on the front side of the motor housing may be exposed.
The belt-shaped member can be changed by attaching it to the motor housing or the housing cover instead of the handle housing. This has the advantage of simplifying the removal procedure. Of course, if the gear housing cover is integrally formed with the motor housing or the gear housing cover can be fixed independently, the belt-like member can be omitted.

  Further, the other structure of the hammer drill is not limited to the above-mentioned form, and the crank housing and the front housing are integrally formed, a plurality of intermediate shafts are provided, the intermediate element is omitted, the housing cover is omitted, and the like are appropriately designed. It can be changed. It may be rechargeable using a battery as a power source. Of course, the present invention is not limited to hammer drills, but can be applied to electric hammers.

  1 .... hammer drill 2 .... housing 3 .... motor 4 .... output shaft 5 .... crank mechanism 6 .... rotation transmission mechanism 7 .... output part 8 .... tool holder 9 ... handle ··· Crankshaft, 14 ·· Intermediate shaft, 17 ·· Cylinder, 18 ·· Piston, 20 ·· Motor housing, 21 ·· Gear housing, 22 ·· Crank housing, 23 ·· Front housing, 24 ·· Handle housing, 25 ·· Gear housing cover, 26 · · Housing cover, 28 · · Cover portion, 29 · · Strike cover, 31 · · Stroke, 38 · · Clutch, 46, 47, 49 · · Bolt, 51 · -Groove, 52-Engagement piece, 54, 55-Boss, 56-Screw, 57-Recess.

Claims (4)

The housing includes a motor housing that houses a motor, and an upper housing that houses a forward-facing output portion at an upper portion of the motor housing, and the motor housing and the upper housing are respectively arranged on the front and rear sides of the motor housing. An impact tool connected by a plurality of screws,
Among the screws, the screw located on the front side of the motor housing is screwed from below, and the screw located on the rear side of the motor housing is screwed from above ,
A handle housing that covers the screw located on the rear side of the motor housing is screwed behind the motor housing and the upper housing, and the screw located on the rear side is exposed by removing the handle housing. A striking tool characterized by The housing includes a motor housing that houses a motor, and an upper housing that houses a forward-facing output portion at an upper portion of the motor housing, and the motor housing and the upper housing are respectively arranged on the front and rear sides of the motor housing. An impact tool connected by a plurality of screws,
Among the screws, the screw located on the front side of the motor housing is screwed from below, and the screw located on the rear side of the motor housing is screwed from above,
A striking tool, wherein a front cover that covers the screw located on the front side of the motor housing is assembled to a front portion of the motor housing . The impact tool according to claim 2 , wherein the front cover is fixed by a belt-like member that is wound around the front cover from the front and attached to the housing. The impact tool according to claim 2 , wherein an engaging portion that engages with each other at an assembly position of the front cover is provided between the upper housing and the front cover.

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