JP2006255837A - Power tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power tool capable of enhancing operability in a narrow space while securing sufficient slip-proof effects and vibration-proof effects. <P>SOLUTION: A hammer drill (the power tool) 1 is composed as follows. An electric motor is housed in a housing 3 including a handle part 3a. The hammer drill is provided with a tip tool, which is driven by the electric motor, at the tip part, and a cover 3 between the tip tool and the housing 3. The cover 4 is joined to the housing 3 at least at three parts with screws. An elastic body 6 is provided on the outer peripheral face of the cover 3. A notch 6a is formed on the elastic body 6 by arranging the elastic body 6 to both sides in the circumferential direction of an extension part 4b across the extension part 4b extended forwardly from a screw seat 4a on the outer peripheral face of the cover 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric power tool in which an elastic body is provided on an outer peripheral surface of a cover screwed to a housing.

  A hammer drill as an example of such a power tool is shown in FIGS. Here, FIG. 7 is a side view of a conventional hammer drill, FIG. 8 is a front view of the hammer drill, and FIG. 9 is a perspective view showing a usage state of the hammer drill.

  As shown in FIG. 8, the conventional hammer drill 101 includes a casing 102 formed by connecting a cover 104 with a screw 105 to a front end portion of a housing 103 including a handle portion 103a, and an electric motor (not shown) is provided in the casing 102. In addition, a power transmission mechanism or the like is incorporated (see Patent Document 1).

  Here, as shown in FIG. 9, screw seats 104a are integrally protruded at four places on the upper, lower, left, and right sides of the connecting portion of the cover 104 to the housing 103, and the cover 104 is located forward (to the screw seat 104a ( Four places are connected to the housing 103 by screws 105 passed from the front side of FIG.

By the way, since this kind of hammer drill 101 performs a stable operation, as shown in FIG. 9, the cover 104 closer to the tip tool 130 is gripped in addition to the handle portion 103a during the operation. The elastic body 107 is provided with an anti-slip function and an anti-vibration function. Here, polycarbonate, nylon, aluminum, or the like is used as the material of the housing 103 or the cover 104, and the material of the elastic body 107 is resin or rubber that is softer than the material of the housing 103 or the cover 104 and has a higher frictional resistance. It is used.

JP-A-10-291173

  However, in the conventional hammer drill 101 shown in FIGS. 7 to 9, the elastic body 107 is provided only in the handle portion 103 a of the housing 103. Anti-vibration was insufficient.

  Therefore, it is proposed to provide the cover 104 with an elastic body. However, if this elastic body is provided on the outer peripheral surface of the cover 104 with substantially the same width, the following problems occur.

  That is, considering the operability in a narrow place of the hammer drill 101, it is desirable that the outer diameter of the cover 104 is as small as possible. However, since the screw seat 104a determines the maximum outer diameter of the cover 104, the cover of the screw seat 104a. It is necessary to suppress the protrusion height from 104 outer peripheral surface as much as possible.

  However, as described above, when the cover 104 is provided with an elastic body having substantially the same width over the entire circumference, the relationship of securing the thread allowance of the screw 105 to the screw seat 104a when the cover 104 is coupled to the housing 103 is ensured. In addition, it is necessary to set the protrusion height of the screw seat 104a higher by the thickness of the elastic body. As a result, the protrusion height of the screw seat 104a from the reference surface of the cover 104 is higher than that in the case where no elastic body is provided. As a result, there is a problem that the operability in a narrow place becomes worse.

  On the other hand, electric tools that partially provide elastic bodies on the sides and bottom of the cover while avoiding the necessary parts for screw installation have also been proposed, but because the range of elastic bodies in the cover is narrow, anti-slip of hands There was a problem that the anti-vibration effect was insufficient.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric tool capable of enhancing the operability in a narrow space while ensuring a sufficient anti-slip effect and an anti-vibration effect. There is.

In order to achieve the above object, according to the first aspect of the present invention, an electric motor is incorporated in a housing including a handle portion, a tip tool driven by the electric motor is provided at the tip portion, and the tip tool and the housing In the electric tool comprising a cover in between and screwing the cover to the housing in at least three places, and providing an elastic body on the outer peripheral surface thereof,
An electric tool characterized in that the elastic body is arranged on both sides in the circumferential direction with an extension extending forward from a screw seat on the outer peripheral surface of the cover.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the cover is formed into two layers together with the elastic body, and the two are integrally formed.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the elastic body is integrally formed by providing a part of the elastic body continuous over the entire circumference of the cover. It is characterized by.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, characterized in that the elastic body is provided on the upper and lower and left and right surfaces of the cover.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the cover is formed in a tapered shape toward the tip.

  According to the first aspect of the present invention, since the elastic body is disposed on both sides in the circumferential direction across the extension (the groove-shaped portion through which the screw passes when the cover is joined) extending forward from the screw seat on the outer peripheral surface of the cover, There is no elastic body in the extension part of the cover, so the protrusion height of the screw seat of the cover can be kept low, the outer diameter of the cover is kept small, and the operability of the power tool in a narrow place is improved. Can do. Further, since there is no elastic body in the extended portion of the cover, the elastic body is not damaged by the screw when the cover is coupled to the housing.

  According to invention of Claim 2, an elastic body can be easily formed integrally with a cover by 2 layer shaping | molding.

  According to the invention described in claim 3, since the elastic body is integrally formed, the elastic body is configured as one part, and the number of parts and the number of processing steps are reduced.

  According to the invention of claim 4, since the elastic body is provided on the upper and lower and left and right surfaces of the cover, the range of the elastic body occupying the outer peripheral surface of the cover is widened, and the anti-slip and vibration-proofing effect by the elastic body is sufficiently ensured. can do.

  According to the invention described in claim 5, since the cover is formed in a tapered shape toward the tip, the extended portion of the outer peripheral surface of the cover ends in the middle of the cover in the front-rear direction, and on both sides in the circumferential direction across the extended portion. A part that is continuous or substantially continuous over the entire circumference of the cover can be formed in a part of the arranged elastic body, which makes it easier to grip the cover and enhances the anti-slip and vibration-proofing effect by the elastic body.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 is a side view of a hammer drill according to the present invention, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, FIG. 3 is a front view of the hammer drill, FIG. 4 is a perspective view showing a usage state of the hammer drill, and FIG. It is a vertical side view which shows the internal structure of the hammer drill.

  The hammer drill 1 according to the present embodiment is configured by incorporating the electric motor 8 and the power transmission mechanism shown in FIG. 5 in the casing 2, but the casing 2 includes a handle portion 3a as shown in FIG. Similarly, a substantially cylindrical cover 4 made of resin is coupled to the front portion of the resin housing 3 with screws 5.

  Here, as shown in FIG. 1, the outer shape of the cover 4 is tapered toward the tip, and as shown in FIGS. The screw seat 4a is integrally formed. As shown in FIGS. 1 and 4, the cover 4 has a groove-shaped extension 4 b (only part of which is shown in FIGS. 1 and 4) extending forward from each screw seat 4 a. Has been. Here, since the outer shape of the cover 4 is tapered toward the tip as described above, each extension portion 4a is also tapered toward the tip and ends in the middle of the cover 4 in the front-rear direction. . The extension 4b is a concave groove for allowing the screw 5 to pass through the screw seats 4a from the front when the cover 4 is screwed to the housing 3. By providing this, the screw 5 and the cover 4 The amount of outward protrusion of the screw seat 4a can be minimized as much as possible.

  By the way, since the hammer drill 1 performs a stable operation, as shown in FIG. 4, the operator holds the cover 4 closer to the tip tool 30 described later with one hand (left hand) and the other hand (right hand). ) To grip the handle portion 3a. In this case, the material of the cover 4 and the housing 3 (polycarbonate, nylon, aluminum, etc.) is used on the outer surface of the cover 4 and the handle 3a of the housing 3 for the purpose of preventing hand slipping and vibration isolation. Also, elastic bodies 6 and 7 (indicated by hatching in the figure) made of a soft resin or rubber having a high frictional resistance are provided. The elastic bodies 6 and 7 are provided integrally with the cover 4 and the housing 3 by two-layer molding, or are formed separately from the cover 4 and the housing 3 and are attached to the outer peripheral surfaces of the cover 4 and the housing 3. The

  Thus, in the present embodiment, as shown in FIGS. 1 to 4, the elastic body 6 provided on the outer peripheral surface of the cover 4 avoids the extension portion 4 b formed on the outer peripheral surface of the cover 4. The V-shaped cutouts 6a are formed in a total of four locations. Here, as described above, since the extension 4a of the cover 4 ends in the middle of the front-rear direction, the notch 6a of the elastic body 6 can also end in the middle of the front-rear direction. A portion continuous over the entire outer periphery of the cover 4 can be formed in the portion (front end portion), and the elastic body 6 can be integrated and configured as one part. It can be placed on the top and bottom and left and right surfaces.

  Next, the internal structure and operation of the hammer drill 1 will be described with reference to FIG.

  The housing 3 incorporates an electric motor 8 as a drive source, and a power cable 9 for supplying power to the electric motor 8 extends from the lower end of the handle portion 3a. In addition, a switch mechanism 10 is built in the handle portion 3a, and a trigger 11 that is operated by an operator is mechanically connected to the switch mechanism 10. The switch mechanism 10 is connected to an external power source (not shown) via the power cable 9, and when the trigger 11 is operated by an operator, the switch mechanism 10 and the external power source are connected and disconnected. Power supply to the electric motor 8 is turned on / off.

  On the other hand, an output shaft (motor shaft) 12 extends horizontally forward from the electric motor 8 built in the horizontal portion (motor housing portion) of the housing 3, and a pinion gear 13 is formed at the tip of the output shaft 12. ing.

  A metal support member 14 that partitions the cover 4 and the housing 3 is provided in the cover 4, and a deceleration chamber 15 is defined by the support member 14 and the cover 4. The cover 4 including the deceleration chamber 15 is filled with grease that is a lubricant for reducing friction of the sliding portion, and this grease is supplied to each sliding portion. In addition, as grease, what has a soap base and oil components, such as silicone oil, as a main component is used.

  Further, an intermediate shaft 16 parallel to the output shaft 12 of the electric motor 8 is provided in the cover 4, and the intermediate shaft 16 has both front and rear ends via bearings 17 and 18 and the cover 4 and a support member. 14 are rotatably supported. A first gear 19 is fixed to the rear end of the intermediate shaft 16, and the first gear 19 meshes with the pinion gear 13 provided on the output shaft 12 of the electric motor 8. Further, a motion conversion unit 20 for converting a rotational motion into a reciprocating motion is externally provided in front of the first gear 19 of the intermediate shaft 16, and is urged rearward by a spring 21 on the intermediate shaft 16. The clutch 22 is spline-fitted.

  Here, the motion converting portion 20 is provided with an arm portion 20a that reciprocates in the front-rear direction by the rotation of the intermediate shaft 16, and the arm portion 20a is slidably fitted in a cylinder 23 described later. The piston 24 is connected to the inserted piston 24 via a piston pin 25. Further, the clutch 22 is moved on the intermediate shaft 16 by the turning operation of the rotary change lever 26 rotatably provided at the lower portion of the cover 4 and is engaged with and disengaged from the motion converting unit 20. The operation mode is switched between hammer drill mode and drill mode.

  By the way, the cylinder 23 is provided in parallel with the intermediate shaft 16 above the intermediate shaft 16 in the cover 4, and the cylinder 16 is rotatably supported by the support member 14. The second gear 27 fixed to the outer periphery of the portion meshes with the gear portion 28 formed at the front end portion of the intermediate shaft 16.

  A tool holding portion 29 is provided at the tip of the cylinder 23, and a tip tool 30 shown in FIG. 4 is detachably attached to the tool holding portion 29. The reason why the support member 14 is made of metal is that the support member 14 supports the pinion gear 13, the intermediate shaft 16 and the cylinder 23, and therefore requires higher mechanical strength than the cover 4 and the housing 3. is there.

  On the other hand, a striking element 31 is fitted in the piston 24 so as to be slidable in the front-rear direction, and an air chamber 32 is defined between the piston 24 in the cylinder 23 and the striking element 31. Further, an intermediate element 33 is slidably inserted in the front and rear direction of the impact element 31 in the cylinder 23, and the impact element 31 is located on the rear end side of the intermediate element 33. The front end tool 30 shown in FIG.

  Next, the operation of the hammer drill 1 configured as described above will be described.

  As shown in FIG. 4, the hammer drill 1 is used for work with the operator holding the cover 4 and the handle 3 a of the housing 3. The operator operates the trigger 11 to activate the electric motor 8. When driven, the output shaft 12 of the electric motor 8 is rotationally driven, the rotation is decelerated through the pinion gear 13 and the first gear 19 and transmitted to the intermediate shaft 16, and the intermediate shaft 16 is rotationally driven at a predetermined speed. The Since the rotation of the intermediate shaft 16 is decelerated via the gear portion 28 and the second gear 27 and transmitted to the cylinder 23, the tool holding portion 29 provided in the cylinder 23 and the tip attached thereto The tool 30 (see FIG. 4) is driven to rotate.

  Here, if the hammer drill mode is selected as the operation mode by rotating the change lever 26, the clutch 22 urged rearward by the spring 21 is engaged with the motion converter 20 as shown in FIG. The rotation of the intermediate shaft 16 is converted into a reciprocating motion in the cylinder 23 of the piston 24 by the motion conversion unit 20. When the piston 24 reciprocates in the front-rear direction in this manner, the air in the air chamber 32 in the cylinder 23 repeatedly compresses and expands, whereby a striking force is intermittently applied to the striking element 31. The striking force is transmitted to the tip tool 30 via the. Accordingly, in the hammer drill mode, a rotational force and a striking force are simultaneously applied to the tip tool 30.

  On the other hand, when the drill mode is selected as the operation mode by the turning operation of the change lever 26, the clutch 22 moves forward on the intermediate shaft 16 against the biasing force of the spring 21, and the motion conversion unit 20 Therefore, the rotation of the intermediate shaft 16 is not transmitted to the motion conversion unit 20, and the piston 24 remains stationary and does not reciprocate. Therefore, in this drill mode, the rotation of the intermediate shaft 16 is transmitted only to the cylinder 23 via the gear portion 28 and the second gear 27, so that only the rotational force is applied to the rotary tool 30.

  As described above, in the hammer drill 1 according to the present embodiment, since the notch 6a is formed in the elastic body 6 provided on the outer peripheral surface of the cover 4, the notch 6a is used to move forward from the screw seat 4a on the outer peripheral surface of the cover 4. The elastic body 6 does not exist in the extended portion 4b (the portion through which the screw 5 is passed when the cover 4 is coupled) extending to. For this reason, the protrusion height of the screw seat 4a of the cover 4 can be kept low, and the protrusion height of the screw seat 4a from the outer peripheral surface of the cover 4 can be kept low as shown in FIG. The operability in a narrow place of the hammer drill 4 can be enhanced by reducing the outer diameter dimension. And since the elastic body 6 does not exist in the extension part 4 b of the cover 4, the elastic body 6 is not damaged by the screw 5 when the cover 4 is coupled to the housing 3.

  In this embodiment, since the elastic body 6 is provided on the upper and lower and left and right surfaces of the outer periphery of the cover 4, the range of the elastic body 6 occupying the cover 4 is widened. Can be secured sufficiently.

  Further, since the cover 4 is tapered toward the tip, the extended portion 4b of the outer peripheral surface of the cover 4 ends in the middle of the cover 4 in the front-rear direction, and is disposed on both sides in the circumferential direction across the extended portion 4b. A part continuous over the entire circumference of the cover 4 can be formed in a part of the elastic body 6, making it easier to grip the cover 4 and improving the anti-slip and vibration-proofing effect of the elastic body 6. Moreover, since the elastic body 6 can be integrally formed as a single component as in the present embodiment, the number of components and the number of processing steps can be reduced.

  If the cover 4 is formed into two layers together with the elastic body 6, the elastic body 6 in which the notch 6 a is formed can be easily provided integrally with the cover 4.

  In this embodiment, the elastic body 6 is integrally formed by providing a part (front end portion) of the elastic body 6 that is continuous over the entire circumference of the cover 4, but as shown in FIG. The elastic body 6 is composed of, for example, four divided pieces 6A, which are provided on the upper and lower and left and right surfaces of the outer periphery of the cover 4, and a notch 6a is formed between the divided pieces 6A adjacent in the circumferential direction. However, the range of the elastic body 6 occupying the cover 4 is widened, and the anti-slip and vibration-proofing effect by the elastic body 6 can be sufficiently secured.

  The present invention can be applied to any power tool in which an elastic body is provided on the outer peripheral surface of a cover screwed to a housing in addition to a hammer drill.

It is a side view of the hammer drill concerning the present invention. It is the sectional view on the AA line of FIG. 1 is a front view of a hammer drill according to the present invention. It is a perspective view which shows the use condition of the hammer drill which concerns on this invention. It is a fracture | rupture side view which shows the internal structure of the hammer drill which concerns on this invention. It is a side view of the hammer drill which shows another form of this invention. It is a side view of the conventional hammer drill. It is a front view of the conventional hammer drill. It is a perspective view which shows the use condition of the conventional hammer drill.

Explanation of symbols

1 Hammer drill (electric tool)
DESCRIPTION OF SYMBOLS 2 Casing 3 Housing 3a Handle part 4 Cover 4a Screw seat 4b Extension part 5 Screw 6,7 Elastic body 6A Split piece 6a Notch 8 Electric motor 30 Tip tool

Claims (5)

An electric motor is built in a housing including a handle portion, a tip tool driven by the electric motor is provided at the tip portion, a cover is provided between the tip tool and the housing, and the cover is provided at least in three places. In the electric tool which is provided with an elastic body on its outer peripheral surface,
An electric tool characterized in that the elastic body is arranged on both sides in the circumferential direction with an extension extending forward from a screw seat on the outer peripheral surface of the cover.   The electric tool according to claim 1, wherein the cover is formed in two layers together with the elastic body, and the two are integrally formed.   The electric tool according to claim 1 or 2, wherein the elastic body is integrally formed by providing a part of the elastic body that is continuous over the entire circumference of the cover.   The electric tool according to any one of claims 1 to 3, wherein the elastic body is provided on upper and lower and left and right surfaces of the cover.   The power tool according to claim 1, wherein the cover is formed in a tapered shape toward the tip.

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