JP2005066804A - Power tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power tool capable of easily performing assembling and disassembling. <P>SOLUTION: An inner case 2, in which a planet gear device 5 is accommodated for reducing the rotation of a motor, is coupled to a front side of a rear housing 1b in which a motor 4 is accommodated, and a front housing 1a, in which an operating part 17 operating by an output of the planet gear device is accommodated, is coupled to the front side of the inner case. In a power tool with this constitution, through male and female screws 18a and 18b using an axial center of the motor and the planet gear device as the axial center of a helix, the inner case is coupled to the rear housing. Without disassembling the planet gear device and the operating part, maintenance and inspection of components such as electrical components 4d included in the rear housing side can be facilitated. In addition, when the power tool is assembled, the assembling operation is easily and quickly performed, by integrally assembling the front housing and the inner case in advance, and then uniting it with the rear housing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electric power tool such as an impact driver.

  In the conventional impact driver, an inner case is fixed to a rear housing housing a motor or the like with a plurality of set screws, and a planetary gear device that is a motor speed reducer is incorporated in the fixed inner case, and the planetary gear device is further incorporated. On the other hand, a hammer or the like is assembled, and finally the front housing housing the bit holder or the like is put on and the front housing is fixed to the inner case (for example, see Patent Document 1).

  Further, the front housing of the conventional impact driver is connected to the inner case by male and female screws, and as a means for preventing the loosening, a large number of concave and convex portions are formed on the outer peripheral surface of the front housing, and the rear housing has a concave and convex portion. A rack that meshes with is attached. After the front housing is screwed into the inner case, the rack on the rear housing is meshed with the concave and convex portions on the front housing, thereby preventing the front housing from rotating relative to the inner case and preventing the male and female screws from loosening. (For example, refer to Patent Document 1).

JP 2003-145439 A

  A motor, various electrical components, and the like are accommodated in the rear housing of the impact driver. When maintaining and inspecting such motors and various electrical components, remove the front housing from the inner case, remove the hammer, planetary gear unit, etc. from the inner case, and finally remove the inner case from the front housing. I have to. Only after the inner case is removed, the front housing can be disassembled, and various electrical components inside it can be inspected and repaired. In general, electrical components such as switches are frequently repaired. However, it is extremely troublesome and inefficient to perform inspection, disassembly, and assembly of a planetary gear device every time such electrical components are inspected and repaired.

  In addition, there is a problem that uneven portions, racks, and the like, which are anti-rotation means, protrude from the outer surface of the housing as protrusions.

  Therefore, an object of this invention is to provide the electric tool which eliminates the said malfunction.

  In order to solve the above problems, the invention according to claim 1 is directed to an inner housing in which a planetary gear device (5) for reducing the rotation of the motor (4) is housed on the front side of the rear housing (1b) housing the motor (4). In the electric tool in which the case (2) is connected, and the front housing (1a) containing the working part (17) operated by the output of the planetary gear device (5) is connected to the front side of the inner case (2). An electric tool in which an inner case (2) is connected to a rear housing (1b) via male and female screws (18a, 18b) having the axes of a motor (4) and a planetary gear unit (5) as a spiral axis. adopt.

  According to a second aspect of the present invention, in the electric tool according to the first aspect, the nut (18) having the female screw (18a) is rotated on the back surface of the rib (24) provided in the rear housing (1b). When the male screw (18b) attached to the inner case (2) is screwed into the female screw (18a), the nut (18) and the inner case (2) are attached via the stopper means (20). And adopting an electric tool sandwiching the rib (24).

  The invention according to claim 3 is the electric tool according to claim 1 or 2, wherein the inner surface of the rear housing (1b) and the outer surface of the inner case (2) inserted into the rear housing (1b) A power tool provided with a means (22) for preventing loosening of the male and female screws (18a, 18b) is used.

  According to a fourth aspect of the present invention, there is provided the electric tool according to any one of the first to third aspects, wherein the inner case is inserted into the inner surface of the front housing (1a) and the front housing (1a). 2) female and male screws (27a, 27b) for connecting the front housing (1a) and the inner case (2) are formed between the outer surface of the female housing (1a) and the inner surface (2). 30) is employed.

  According to the invention which concerns on Claim 1, the inner case (2) which accommodated the planetary gear apparatus (5) which decelerates rotation of a motor (4) in the front side of the rear housing (1b) which accommodated the motor (4). In the electric tool in which the front housing (1a) that houses the working unit (17) that is operated by the output of the planetary gear device (5) is connected to the front side of the inner case (2), the motor (4) and The inner case (2) is an electric tool in which the inner case (2) is connected to the rear housing (1b) via male and female screws (18a, 18b) having the axis of the planetary gear unit (5) as a spiral axis. By twisting the rear housing (1b) in a state where (2) and the front housing (1a) are integrated, the housing (1) can be divided into two at the locations of the male and female screws (18a, 18b). Accordingly, maintenance, inspection, and the like of the electrical component (4d) and the like included in the rear housing (1b) can be easily performed without disassembling the planetary gear unit (5), the working unit (17), and the like. Also, when assembling the electric tool, the front housing (1a) and the inner case (2) may be assembled and integrated first, and then combined with the rear housing (1b). Is simplified and speeded up. Further, the inner case (2) and the front housing (1a) include a planetary gear unit (5) and a working unit (17) using a lubricating oil such as grease, and the rear housing (1b) is an electrical component that dislikes dirt ( 4d), but the front housing (1a) and the inner case (2) side can be assembled separately on the rear housing (1b) side. Is prevented.

  According to the invention according to claim 2, in the electric tool according to claim 1, the nut (18) having the female screw (18a) on the back surface of the rib (24) provided in the rear housing (1b) rotates. When the male screw (18b) attached to the inner case (2) is screwed into the female screw (18a), the nut (18) and the inner case (2) are attached via the stopper means (20). Since the rib (24) is clamped, the backlash in the thrust direction of the inner case (2) in the housing (1) is eliminated. Further, the nut (18) is loosened by twisting the inner case (2) and the front housing (1a) integrally with the rear housing (1b), and the rear housing (1b) is separated from the inner case (2) and the like. be able to.

  According to a third aspect of the present invention, in the electric tool according to the first or second aspect, the inner surface of the rear housing (1b) and the outer surface of the inner case (2) inserted into the rear housing (1b) Since the locking means (22) for the female and male screws (18a, 18b) is provided between the rear housing (1b) and the inner case (2), the tightened state of the female and male screws (18a, 18b) is maintained. ) Can be prevented. Moreover, since the locking means (22) is housed inside the rear housing (1b), the formation of protrusions on the surface of the rear housing (1b) is prevented.

  According to the invention which concerns on Claim 4, in the electric tool in any one of Claim 1 thru | or 3, the inner case inserted in the inner surface of the front housing (1a) and the front housing (1a) ( 2) female and male screws (27a, 27b) for connecting the front housing (1a) and the inner case (2) are formed between the outer surface of the female housing (1a) and the inner surface (2). Since 30) is provided, it is possible to prevent backlash between the front housing (1a) and the inner case (2) due to loosening of the male and female screws (27a, 27b). Further, since the rotation preventing means (30) is housed inside the front housing (1a), the formation of protrusions on the surface of the front housing (1a) is prevented.

  The best mode for carrying out the invention will be described below with reference to the drawings.

  As shown in FIGS. 1 and 2, an impact driver that is an electric power tool includes a housing 1 that is divided into front and rear portions.

  Although the front housing 1a is molded from the beginning as a cylindrical integral, the rear housing 1b is molded in two. As shown in FIGS. 4 and 5, the rear housing 1b is assembled by aligning the two split pieces from the left and right sides and fixing them with a set screw or the like. The housing 1 of the impact driver is integrated by connecting the front housing 1a and the rear housing 1b via an inner case 2 housed between them.

  In the housing 1, a motor 4, a planetary gear device 5 that decelerates the rotation of the motor output shaft 4a, and a working unit 17 that receives power from the carrier output shaft 5a of the planetary gear device 5 and performs operations such as screw tightening. Are arranged in series from the rear to the front.

  The motor 4 is housed in the rear housing 1b, and the front and rear portions of the motor output shaft 4a integral with the armature 4b are supported by the housing 1 via bearings 6 and 7, respectively. Further, the stator 4c and the like of the motor 4 are fixed to the inner wall surface of the rear housing 1b. When the motor 4 is started, the motor output shaft 4 a rotates while being supported by the bearings 6 and 7. As shown in FIGS. 1 and 2, various electrical components such as a switch 4d for turning on / off the motor 4 are also housed in the rear housing 1b. A handle 1c is provided integrally with the rear housing 1b. A trigger 16 for turning on / off the switch 4c is provided at the base of the handle 1c.

  The planetary gear device 5 is housed in the inner case 2 and is held by the housing 1 via the inner case 2. The planetary gear device 5 uses a pinion 3 formed at the front portion of the motor output shaft 4a as a sun gear, and supports a plurality of planetary gears 5b meshing with the pinion 3 around the pinion 3 and the planetary gear 5b in a rotatable manner. Carrier 5c, and an internal gear 5d that meshes with the planetary gear 5b. The internal gear 5 d is fixed to the inner peripheral surface of the inner case 2, and the carrier 5 c is rotatably supported in the inner case 2 via a bearing 8. The rotation of the motor output shaft 4a is decelerated by the planetary gear device 5 and output from the carrier 5c.

  The carrier 5c is integrally provided with a carrier output shaft 5a protruding forward from the inner case 2 into the front housing 1a. The carrier output shaft 5a constitutes a camshaft of an impact driver, and a spiral groove 9 whose both ends are closed is formed at the tip of the carrier output shaft 5a. The carrier output shaft 5 a is covered with a cylindrical hammer 10, and a longitudinal groove 11 having a closed rear end is formed on the inner surface of the hammer 10. The hammer 10 is connected to the carrier output shaft 5 a by a steel ball 12 inserted so as to straddle between the spiral groove 9 and the longitudinal groove 11. The hammer 10 is always urged forward by a compression coil spring 13 provided around the carrier output shaft 5a, and stops at a position where the ball 12 contacts the front end of the spiral groove 9 and the rear end of the vertical groove 11. When the carrier output shaft 5 a rotates integrally with the carrier 5 c, the hammer 10 twists on the carrier output shaft 5 a against the urging force of the compression coil spring 13 by the engagement of the spiral groove 9, the longitudinal groove 11 and the ball 12. Then, the hammer 10 moves forward while being twisted in the opposite direction on the carrier output shaft 5a due to the elasticity of the compression coil spring 13, and the hammer 10 performs reciprocating angular motion while repeating this forward and backward movement.

  A cavity is formed on the axis of the carrier 5c and the carrier output shaft 5a, and the pinion 3 of the motor output shaft 4a meshes with the planetary gear 5b in the cavity. Further, the motor output shaft 4a protrudes forward from the planetary gear 5b, and this protruding portion is supported on the inner wall surface of the cavity of the carrier output shaft 5a via the bearing 6. The front end portion of the motor output shaft 4 a is directly supported by the bearing 6, but is supported by the housing 1 via the carrier 5 c, the carrier output shaft 5 a, the bearing 8, and the inner case 2.

  The front housing 1a accommodates a working portion 17 that is operated by the output of the planetary gear device 5. That is, the carrier output shaft 5a, the hammer 10, the bit holder 14 and the like are accommodated. The bit holder 14 is disposed in front of the carrier output shaft 5a and the hammer 10 and is rotatably supported by the front housing 1a. The tip of the bit holder 14 protrudes outside the front housing 1a, and a bit (not shown) is detachably attached to the protruding portion. Two arms 14a protrude in the radial direction from the rear end of the bit holder 14, and two claw pieces 10a protruding from the hammer 10 abut against each arm 14a in the circumferential direction. As described above, when the hammer 10 reciprocates while moving forward and backward, the claw piece 10a of the hammer 10 repeatedly strikes the arm 14a of the bit holder 14 in the circumferential direction, and the bit holder 14 is intermittent in one direction. Rotate to. As a result, the bit fixed to the bit holder 14 is screwed or the like.

  As described above, the inner case 2 that houses the planetary gear device 5 that decelerates the rotation of the motor 4 is connected to the front side of the rear housing 1 b that houses the motor 4, and the planetary gear device 5 is connected to the front side of the inner case 2. The front housing 1a that houses the working unit 17 that is activated by the output is connected. As shown in FIGS. 2 and 5, the inner case 2 is connected to the rear housing 1b with the shafts of the motor 4 and the planetary gear unit 5. They are connected via male and female screws 18a and 18b, which are the axes of the spirals.

  As a result, when the inner case 2 and the front housing 1a are integrated with each other and the rear housing 1b is twisted in the loosening direction of the female and male screws 18a and 18b, the housing 1 is divided into two parts at the positions of the female and male screws 18a and 18b. The rear housing 1b can be removed without disassembling the planetary gear unit 5, the working unit 17, and the like. The removed rear housing 1b is disassembled into two split pieces by loosening a set screw 19 as shown in FIG. 4, and an electrical component such as the switch 4d can be taken out.

  Moreover, the electric tool can be easily assembled by assembling and integrating the front housing 1a and the inner case 2 with the rear housing 1b. The inner case 2 and the front housing 1a include a planetary gear unit 5 and a working unit 17 that use lubricating oil such as grease, and the rear housing 1b includes electrical components that do not like dirt, but the front housing 1a and the inner case 2 By performing the assembly on the side separately from the assembly on the rear housing 1b side, the electrical components such as the switch 4d are prevented from being damaged.

  As shown in FIGS. 2 and 5, the female screw 18 a of the female male screw 18 a and 18 b is specifically formed on the nut 18. This nut 18 is attached to the back surface of the rib 24 provided in the rear housing 1b via a detent means. The rotation preventing means includes a protrusion 20 protruding from the peripheral surface of the nut 18 and a hole 21 into which the protrusion 20 formed on the inner surface of the rear housing 1b enters. The male and female screws 18b of the female and male screws 18a and 18b are formed on the outer peripheral surface of the rim-shaped cylindrical portion 2a that projects rearward from the back surface of the inner case 2 so as to surround the motor output shaft 4a.

  When the inner case 2 and the front housing 1a are integrally rotated with respect to the rear housing 1b in one direction around the axial center, the male screw 18b of the inner case 2 is screwed into the female screw 18a of the nut 18, thereby the inner case. The front part from 2 is connected to the rear housing 1b. At the same time as the connection, the rib 24 is sandwiched between the nut 18 and the inner case 2 so that the backlash in the thrust direction of the inner case 2 in the housing 1 is eliminated. Further, when the inner case 2 and the front housing 1a are integrated and twisted in the opposite direction around the axis with respect to the rear housing 1b, the male and female screws 18a and 18b are loosened, and the rear housing 1b is separated from the inner case 2 and the like.

  As shown in FIGS. 2 and 4, between the inner surface of the rear housing 1b and the outer surface of the inner case 2 inserted into the rear housing 1b, male and female screws 18a for coupling the inner case 2 and the rear housing 1b, An anti-loosening means 18b is provided.

  The loosening prevention means includes a large number of uneven portions 2b formed on the outer peripheral surface of the inner case 2 at a constant pitch, an engaging piece 22 having an uneven portion 22a fitted into the uneven portion 2b, and the engaging piece 22 as an inner portion. And a pressing screw 23 to be pushed into the case 2 side. The locking piece 22 is fitted in a guide groove 25 formed on the inner surface of the rear housing 1b so as to extend in the radial direction of the inner case 2, and the pressing screw 23 is formed on the wall of the rear housing 1b toward the back surface of the locking piece 22. Screwed into the female screw of the drilled screw hole 26.

  When the pressing screw 23 is screwed in a state where the male screw 18b of the inner case 2 is screwed with the female screw 18a of the nut 18, the concave / convex portion 22a of the locking piece 22 is fitted into the concave / convex portion 2b of the inner case 2, and the rear portion The relative rotation between the housing 1b and the inner case 2 is prevented. Thereby, loosening of the male and female screws 18a and 18b is prevented, and rattling in the axial direction between the rear housing 1b and the inner case 2 is prevented. After the locking operation, the head of the pressing screw 23 is buried in the screw hole 26 below the surface of the rear housing 1b.

  As shown in FIG. 2, the front housing 1 a is connected to the inner case 2 via male and female screws 27 a and 27 b having the axis of the planetary gear device 5 as a spiral axis. That is, male and female screws 27a and 27b for connecting the front housing 1a and the inner case 2 are formed between the inner surface of the front housing 1a and the outer surface of the inner case 2 inserted into the front housing 1a. When the front housing 1a is twisted with respect to the inner case 2 in the tightening direction of the male and female screws 27a and 27b, the front housing 1a is coupled to the inner case 2 at the positions of the female and male screws 27a and 27b. Etc. are enclosed in the cavity of both.

  As shown in FIGS. 2 and 3, the male and female screws 27 a and 27 b are provided with locking means between the inner surface of the front housing 1 a and the outer surface of the inner case 2 so as to be adjacent to the male and female screws 27 a and 27 b. Provided.

  The loosening prevention means includes a plurality of first uneven portions 28 formed on the outer peripheral surface of the inner case 2 at a constant pitch, and a pitch different from the pitch of the first uneven portions 28 on the inner peripheral surface of the front housing 1a. Alternatively, it is formed by a local match between a large number of second concavo-convex portions 29 formed so as to be shifted in the front-rear direction from the first concavo-convex portion 28, and the first and second concavo-convex portions 28, 29. And a key 30 inserted into the communication groove. The first and second concavo-convex portions 28 and 29 are formed so as to extend parallel to the axis of the front housing 1 a and the inner case 2. The key 30 is formed in an elongated plate shape, and a small hole 30a for locking a tool or the like when the key 30 is pulled out from the communication groove is formed at one end thereof.

  When the male screw 27b of the inner case 2 is screwed into the female screw 27a of the front housing 1a, the first and second concavo-convex parts 28 and 29 are locally matched to form one or more grooves in the front-rear direction. Communicate. Therefore, when the key 30 is inserted into the communication groove, relative rotation between the front housing 1a and the inner case 2 is prevented. Thereby, the looseness of the male and female screws 27a and 27b is prevented, and rattling between the front housing 1a and the inner case 2 is prevented. After the loosening prevention operation, the rear portion where the small hole 30a of the key 30 is formed protrudes from the communication groove, but this protruding portion is buried in the gap between the inner case 2 and the rear housing 1b covering the inner case 2.

  Next, the operation of the impact driver configured as described above will be described.

  The impact driver is assembled in the following procedure.

  The planetary gear device 5 and the like are incorporated in the inner case 2 and the bit holder 14 and the like are incorporated in the front housing 1a, and the male and female screws 27a and 27b are screwed together as shown in FIG. Connect 1a.

  When the male and female screws 27a and 27b are screwed together, as shown in FIG. 3, the first and second concave and convex portions 28 and 29, which are locking means, are locally matched to form several communication grooves. . Therefore, when the key 30 is inserted into each communication groove, the relative rotation between the front housing 1a and the inner case 2 is prevented, and the loosening of the male and female screws 27a and 27b is prevented.

  Further, electric parts such as the motor 4 and the switch 4d are incorporated in the split piece of the rear housing 1b, and the split pieces are fixed with a set screw 19 or the like. As shown in FIG. 5, the nut 18 is assembled in the split piece, and the projection 20 is inserted into the hole 21 in the rear housing 1b.

  An inner case 2 integrated with the front housing 1a is inserted into a cavity in front of the motor 4 in the rear housing 1b, and the inner case 2 and the front housing 1a are integrated with each other around the axis with respect to the rear housing 1b. Turn in one direction. Thereby, the male screw 18b of the inner case 2 is screwed into the female screw 18a of the nut 18, and the front part from the inner case 2 is connected to the rear housing 1b. By the screwing of the nut 18 and the inner case 2, the rib 24 of the rear housing 1 b is sandwiched between the nut 18 and the inner case 2, and the thrust of the inner case 2 in the housing 1, that is, the play in the axial direction is prevented.

  When the connection between the inner case 2 and the rear housing 1b of the front housing 1a is completed, as shown in FIG. 2, the rear portion of the key 30 protruding rearward from the communication groove covers the inner case 2 and the inner case 2. It is buried in the gap with 1b.

  When the screwing between the nut 18 and the inner case 2 is completed, the pressing screw 23 is screwed to fit the uneven portion 22a of the locking piece 22 into the uneven portion 2b of the inner case 2 as shown in FIG. Thereby, the relative rotation of the rear housing 1b and the inner case 2 is prevented, and the loosening of the male and female screws 18a and 18b is prevented. After the locking operation, the head of the pressing screw 23 is buried in the screw hole 26 below the surface of the rear housing 1b.

  When the trigger 16 of the impact driver assembled as described above is operated and the switch 4d is turned on, the motor output shaft 4a rotates while being supported by the bearings 6 and 7 when the motor 4 is started. The rotation of the motor output shaft 4a is decelerated by the planetary gear device 5 and output from the carrier output shaft 5a. When the carrier output shaft 5a rotates, the hammer 10 performs reciprocating angular motion while repeating forward and backward movements.

  When the hammer 10 performs reciprocating angular movement while repeating forward and backward movement, the claw piece 10a of the hammer 10 repeatedly strikes the arm 14a of the bit holder 14 in the circumferential direction, and the bit holder 14 rotates intermittently in one direction. As a result, a bit (not shown) fixed to the bit holder 14 is screwed.

  When maintenance, inspection, repair or the like of the switch 4d and the like is performed after repeated use of the impact driver, the housing 1 is opened by the following procedure.

  After releasing the locking means, the inner case 2 and the front housing 1a are integrally twisted in the opposite direction around the axis with respect to the rear housing 1b. As a result, the male and female screws 18a and 18b are loosened and separated into the front and rear two parts of the rear housing 1b, the inner case 2 and the front housing 1a.

  Since the inner case 2 and the front housing 1a are integrally removed from the rear housing 1b, the planetary gear device 5 and the working unit 17 remain assembled in the inner case 2 and the front housing 1a without being disassembled. Placed.

  Open the split piece of the rear housing 1b, take out the electrical parts such as the switch 4d, and perform inspection, repair, etc.

  Thereafter, the impact driver is reassembled by the above assembling procedure and is subjected to screw tightening work or the like.

It is a fragmentary sectional view which removes and shows a part of housing of the impact driver which concerns on this invention. In FIG. 1, it is an enlarged view of the principal part. FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. In FIG. 2, it is a VV arrow directional cross-sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Housing 1a ... Front housing 1b ... Rear housing 2 ... Inner case 4 ... Motor 4d ... Switch 5 ... Planetary gear unit 17 ... Working part 18 ... Nut 18a, 18b ... Female and male screw 20 ... Protrusion 22 ... Locking piece 24 ... Ribs 27a, 27b ... male and female screws 30 ... key

Claims (4)

  A front housing in which an inner case that houses a planetary gear device that decelerates rotation of the motor is connected to the front side of the rear housing that houses the motor, and a working portion that is operated by the output of the planetary gear device is housed in the front side of the inner case. An electric tool characterized in that the inner case is connected to the rear housing via a male and female screw having a helical shaft as the shaft center of the motor and the planetary gear device.   The electric tool according to claim 1, wherein a nut having the female screw is attached to a back surface of a rib provided in the rear housing via a detent means, and the male screw provided in the inner case is attached to the female screw. An electric tool characterized in that the rib is sandwiched between a nut and an inner case by screwing.   The electric tool according to claim 1 or 2, characterized in that a locking means for the male and female screws is provided between the inner surface of the rear housing and the outer surface of the inner case inserted into the rear housing. Electric tool to do.   4. The electric power tool according to claim 1, wherein the front housing and the inner case are connected between the inner surface of the front housing and the outer surface of the inner case inserted into the front housing. A power tool characterized in that a male and female screw is formed and means for preventing the female and male screw from being loosened is provided.

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