JP5012661B2 - Driving tool - Google Patents

Description

  The present invention relates to a drive tool, and more specifically, a gear is directly formed at the tip of an output shaft of a motor, and a bit installed at the tip of the tool is rotated by rotating an intermediate shaft through a gear meshing with the gear. The present invention relates to a drive tool that rotates and applies an impact force.

  A hammer drill that is generally used today is configured to rotate a bit installed at the tip of a tool and to apply a blow to the bit that is driven to rotate. It has a structure that realizes the ability (see, for example, Patent Document 1).

  As shown in FIG. 4, in the general hammer drill 40, the rotational force on the output shaft 41 of the motor is transmitted to the intermediate shaft 43 through the first gear 42 to rotate the intermediate shaft 43, and further the intermediate shaft 43. The cylinder 46 to which the bit 45 is fixed is rotated through the second gear 44 meshed with the first gear 44.

  The intermediate shaft 43 has a boss 48 that is loosely fitted to the intermediate shaft 43, a connecting arm 49 that is rotatably attached along a groove formed on the outer periphery of the boss 48 in a state where the axis is inclined, A clutch 50 for rotating the boss 48 according to the rotation of the intermediate shaft 43 by engaging the intermediate shaft 43 and the boss 48 is provided. When the intermediate shaft 43 is rotated with the clutch 50 connected, the boss 48 rotates corresponding to the rotation of the intermediate shaft 43, and the connecting arm 49 provided on the outer periphery of the boss 48 is connected according to the rotation of the boss 48. The tilt direction of the arm 49 is changed, and the tip part moves forward and backward along the extending direction of the cylinder 46 in accordance with the tilt change. A mechanism for converting the rotational motion into the forward / backward motion based on the movement of the connecting arm 49, the boss 48, etc. is called a reciprocating mechanism.

In this way, the rotational movement of the intermediate shaft 43 is converted into the forward / backward movement via the connecting arm 49, and the impact force is applied to the bit 45 by driving the piston cylinder 52 in response to the forward / backward movement. It is possible.
JP 2004-167638 A

  Since such a hammer drill 40 has a structure in which an impact force is applied to the bit 45, vibration due to the impact force or when the concrete or the like is actually crushed is transmitted to the tool via the bit 45. Due to vibration / impact, the components inside the tool are impacted. As a result, the ball bearing 53 that rotatably supports the output shaft 41 is damaged, and the tooth surface of the first gear 42 that meshes with the output shaft 41 is worn. There was a problem that it might occur.

  It is necessary to pivotally support the output shaft 41 of the motor so that the output shaft 41 of the motor does not move (vibrate) against such an impact force. However, in a hammer drill using a reciprocating mechanism, Since there is almost no space in the internal structure, there is a problem that it is not easy to install a member for suppressing the vibration of the output shaft 41.

  In particular, as shown in Patent Document 1, a gear 54 that meshes directly with the first gear 42 is provided directly at the tip of the output shaft 41 (the gear 54 is cut directly at the tip of the output shaft 41), and the bit is fed from the motor. In the hammer drill 40 designed to shorten the dimension up to the 45 attachment position as much as possible, the installation of the vibration suppressing member on the output shaft 41 tends to be more difficult.

  On the other hand, there is a problem that the low-viscosity grease filled in the installation location of the cylinder 46 and the installation location of the intermediate shaft 43 may enter the motor installation location.

  In order to prevent such grease from entering, it is preferable to install an oil seal in the vicinity of the tip position of the output shaft 41. However, as described above, there is a problem that installation is difficult because there is not enough installation space. It was. Such a problem is more conspicuous in the hammer drill 40 having the output shaft 41 in which the gear 54 is directly cut as described above.

  The present invention has been made in view of the above problems, and in a driving tool in which a gear is formed by direct cutting with respect to the output shaft of the motor, the output shaft is properly supported so that the output shaft of the motor does not move easily. Another object of the present invention is to provide a driving tool that can prevent grease from entering at the tip position of the output shaft of the motor.

  In order to solve the above problems, a driving tool according to the present invention includes a ball bearing that rotatably supports an output shaft of a motor, a gear that meshes with a gear that is directly formed with respect to a tip of the output shaft, An intermediate shaft that meshes with a gear and is rotationally driven as the output shaft rotates, a rotational drive means that rotationally drives a bit installed at the tip of the tool as the intermediate shaft rotates, and rotation of the intermediate shaft And an impact applying means for applying an impact force to the bit. The sleeve is fixed to the output shaft, and the sleeve is brought into contact with the front surface of the ball bearing.

  As described above, the drive tool according to the present invention has a structure in which the sleeve is fixed to the output shaft and the sleeve is brought into contact with the front surface portion of the ball bearing. For this reason, even when the output shaft is subjected to vibration or the like by an impact force such as an impact applying means, the sleeve is brought into contact with the front surface portion of the ball bearing, so that the output shaft is moved by vibration. Can be prevented. Accordingly, it is possible to reduce damage to the ball bearing, gear tooth wear, and the like due to movement of the output shaft.

  The drive tool may be an oil seal installed on the sleeve.

  As described above, by installing the oil seal on the sleeve, it is possible to install the oil seal between the meshing position of the gear and the output shaft and the ball bearing. For this reason, it becomes possible to effectively prevent the grease from entering the motor side from the meshing position with the gear.

  Furthermore, by fixing the sleeve to the output shaft, even if the drive tool has a gear directly formed at the tip of the output shaft, the oil seal is attached to the output shaft in a state where the output shaft and the gear are integrally formed. It becomes easy to install, and the length of the output shaft can be maintained at the same length as that of a conventional drive tool.

  According to the driving tool of the present invention, since the sleeve is fixed to the output shaft and the sleeve is brought into contact with the front portion of the ball bearing, the output shaft is subjected to vibrations generated by the impact applying means or the like. Even in this case, it is possible to prevent the sleeve from coming into contact with the ball bearing and moving the output shaft due to vibration. For this reason, it becomes possible to reduce the damage of the ball bearing due to the movement of the output shaft, the tooth surface wear of the gear, and the like.

  Hereinafter, a driving tool according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a side sectional view showing a hammer drill as an example of a driving tool according to the present embodiment.

  In the hammer drill 1, a motor 3 is accommodated in the rear interior (right side in FIG. 1) of the main body housing 2. An output shaft 4 of the motor 3 is rotatably supported via a ball bearing 7 with respect to an inner housing 6 assembled in the main body housing 2. A gear 4 a that meshes with a first gear (gear) 13 described below is directly formed (directly cut) with respect to the output shaft 4 at the distal end portion of the output shaft 4. A detailed configuration near the installation position of the ball bearing 7 with respect to the output shaft 4 will be described later.

  An intermediate shaft 11 supported by ball bearings 8 and 9 is provided on the front side of the inner housing 6, and the intermediate shaft 11 is installed so as to be parallel to the output shaft 4. . A first gear 13 is meshed with the rear end portion of the intermediate shaft 11, and a gear 4 a of the output shaft 4 is meshed with the first gear 13. Therefore, when the output shaft 4 of the motor 3 rotates, the rotation of the output shaft 4 is transmitted to the intermediate shaft 11 via the first gear 13 so that the intermediate shaft 11 rotates.

  Further, on the front side of the inner housing 6 in the main body housing 2, the ball bearing 14 provided in the main body housing 2 via the bush 15 and the slide bearing 16 provided in the inner housing 6 advance and retract in the main body housing 2. A cylinder 18 is provided which is rotatably supported in a state where movement is permitted. A bit 20 can be inserted into the front portion of the cylinder 18.

  A second gear 21 provided in front of the intermediate shaft 11 is meshed with the cylinder 18. Therefore, when the intermediate shaft 11 rotates, the rotation of the intermediate shaft 11 is transmitted to the cylinder 18 via the second gear 21, and the bit 20 can be driven to rotate as the cylinder 18 rotates. For this reason, the 2nd gear 21 and the cylinder 18 have a role as a rotational drive means based on this invention.

  On the other hand, a boss 22 is loosely fitted to the intermediate shaft 11 so as to be rotatable with respect to the intermediate shaft 11, and is loosely fitted to the outer periphery of the boss 22 via a steel ball 28 with the axis line inclined. The connecting arm 25 is attached. In addition, a clutch 26 is provided on the front side of the boss 22 so as to be spline-coupled to the intermediate shaft 11 so as to rotate integrally and to slide in the axial direction. The clutch 26 includes a plurality of clutch claws, and can be engaged with the intermediate shaft 11 and the boss 22 by the engagement of the clutch claws.

  When the clutch 26 is engaged with the boss 22 and the intermediate shaft 11 using the clutch pawl, the rotation of the intermediate shaft 11 is transmitted to the boss 22 through the clutch 26, and the connecting arm is provided with the axis inclined. The 25 arm tips 25 a can be moved forward and backward with respect to the extending direction of the cylinder 18 as the boss 22 rotates.

  On the other hand, when the clutch 26 releases the clutch pawl and releases the engagement with the boss 22 and the intermediate shaft 11, the rotation of the intermediate shaft 11 is not transmitted to the boss 22, and is caused by the arm tip 25 a of the connecting arm 25. The advance / retreat can be stopped.

  The arm tip 25 a of the connecting arm 25 is pivotally attached to the rear end of a piston cylinder 18 a provided in the cylinder 18. A striking element 27 is slidably accommodated in the piston cylinder 18 a via an air chamber 30. Further, a collision with the striking element 27 is located in front of the striking element 27 and inside the front end of the cylinder 18. Accordingly, an intermediate element 29 for applying an impact force to the bit 20 is accommodated.

  When the arm tip 25a of the connecting arm 25 starts to advance and retreat, the piston cylinder 18a starts to be driven as the arm tip 25a advances and retracts, and the sliding movement of the striker 27 is started. When the striker 27 is slid to the front side of the cylinder 18 due to a change in the pressure state of the air chamber 30 as the piston cylinder 18 a is driven, the striker 27 collides with the intermediate member 29 and forwards due to the collision with the striker 27. The meson 29 repelled hits the cylinder 18 by the impact.

  When the striking force of the meson 29 is applied to the cylinder 18, the striking force is transmitted to the bit 20 and it becomes possible to improve the drilling performance in the drilling operation. For this reason, the boss 22, the connecting arm 25, the clutch 26, the piston cylinder 18 a, the striker 27, and the intermediate element 29 have a role as impact applying means according to the present invention.

  FIG. 2A is a developed perspective view showing an assembled state of the motor 3 with respect to the inner housing 6, and FIG. 2B shows a developed side view thereof. FIG. 3 is a side sectional view showing a state in which the motor 3, the inner housing 6, the intermediate shaft 11, the clutch 26, the boss 22, the connecting arm 25, and the piston cylinder 18a are assembled. Yes.

  As described above, the gear 4 a is directly formed (directly cut) at the tip of the output shaft 4 of the motor 3. A cooling fan 33 for cooling the motor 3 is fixed at a position in the vicinity of the rotor 3 a of the output shaft 4. Further, a ball bearing 7 is provided at a front position of the cooling fan 33 via a plate 34, and a sleeve 36 is press-fitted and fixed to the output shaft 4 at the front position.

  Note that the front end portion 33 a of the cooling fan 33 is in contact with the rear end portion of the ball bearing 7 through the opening 34 a of the plate 34. Further, as shown in FIG. 3, the sleeve 36 is provided so as to cover only a part of the gear groove at the rear end portion of the gear 4a. Further, an oil seal 37 is fitted on the outer peripheral portion of the sleeve 36.

  In this way, the output shaft 4 is inserted into the output shaft opening 6 a of the inner housing 6 with the cooling fan 33, the plate 34, the ball bearing 7, the sleeve 36, and the oil seal 37 attached to the output shaft 4. The plate 34 is fixed to the edge portion of the output shaft opening 6a by screws 38 in a state where the sleeve 36, the oil seal 37, and the ball bearing 7 are provided in the output shaft opening 6a. . By fixing the plate 34 to the inner housing 6 in this way, the gear 4a at the tip of the output shaft 4 is engaged with the first gear 13 located on the lower front side of the inner housing 6 as shown in FIG. In addition, an oil seal 37 is installed via a sleeve 36 between the gear 4a portion of the output shaft 4 and the ball bearing 7 that rotatably supports the output shaft 4, so that the meshing position of the first gear 13 is achieved. Thus, it is possible to prevent the grease that is about to enter the motor 3 through the oil seal 37.

  Further, since the ball bearing 7 is installed in the inner housing 6 in a state where the rear surface portion is regulated by the plate 34 fixed by the screw 38, the state in which the ball bearing 7 is positioned in the inner housing 6 is maintained. The output shaft 4 does not move backward in the extending direction. In such a state, since the sleeve 36 is press-fitted and fixed to the front side of the ball bearing 7, even if the output shaft 4 tries to move to the rear side, the rear end (rear surface portion) of the sleeve 36 has the ball bearing 7. The output shaft 4 is prevented from moving backward by being brought into contact with the front surface portion. On the other hand, since the front end portion 33a of the cooling fan 33 is in contact with the rear end portion of the ball bearing 7, the advancement of the output shaft 4 is restricted even if the output shaft 4 tries to advance.

  Thus, in the hammer drill 1 according to the present embodiment, the output shaft 4 is installed in the inner housing 6 so that the ball bearing 7 is sandwiched between the sleeve 36 fixed to the output shaft 4 and the cooling fan 33. The rearward movement of the shaft 4 can be restricted by the contact of the sleeve 36 with the ball bearing 7, and the forward movement of the output shaft 4 can be restricted by the contact of the cooling fan 33 with the ball bearing 7. can do.

  For this reason, even if the vibration accompanying the sliding movement of the striker 27 and the intermediate element 29 or the vibration input via the bit 20 is transmitted to the output shaft 4, the output shaft 4 moves forward or rearward. Thus, it is possible to prevent moving back and forth easily. Accordingly, it is possible to suppress the damage of the ball bearing 7 accompanying the movement of the output shaft 4 and the wear of the tooth surface of the first gear 13.

  Further, the sleeve 36 is fitted so as to cover only a part of the gear groove at the rear end of the gear 4a, so that the length of the output shaft 4 is kept short as in the prior art while the length of the output shaft 4 is maintained. The oil seal 37 can be installed between the meshing position of the gear 4 a and the first gear 13 and the installation position of the ball bearing 7 on the output shaft 4. For this reason, it becomes possible to shorten the dimension from the motor 3 to the attachment position of the bit 20 similarly to the conventional hammer drill.

  Further, since the oil seal 37 can be installed between the meshing position with the first gear 13 and the installation position of the ball bearing 7 of the output shaft 4, the motor 3 is moved from the meshing position with the first gear 13. It is possible to effectively prevent the grease from entering the side.

  As described above, the hammer drill 1 according to the present embodiment has a structure in which the sleeve 36 is press-fitted and fixed to the front side of the ball bearing 7 that supports the output shaft 4 so as to contact the ball bearing 7. Even when the output shaft 4 receives vibration of impact force generated by the striking element 27 and the intermediate element 29 or when vibration during the drilling operation is transmitted through the bit 20 in the drilling operation, the sleeve 36 is moved to the ball bearing 7. It is possible to regulate the movement of the output shaft 4 by making it abut on. For this reason, it becomes possible to reduce the damage of the ball bearing 7 due to the movement of the output shaft 4 and the tooth surface wear of the first gear 13.

  Further, even if the hammer drill 1 has the gear 4a directly formed at the tip of the output shaft 4 by press-fitting and fixing the sleeve 36 to the output shaft 4, the length of the output shaft 4 is the same as the conventional one. It is possible to install the oil seal 37 in a state where the pressure is suppressed to the minimum.

  Further, since the oil seal 37 can be installed by providing the sleeve 36 between the meshing position of the output shaft 4 with the first gear 13 and the installation position of the ball bearing 7, the first gear 13 is Thus, it is possible to effectively prevent the grease from entering the motor 3 side.

  As mentioned above, although the drive tool which concerns on this invention was demonstrated in detail using drawing, the drive tool which concerns on this invention is not limited only to the hammer drill 1 shown in embodiment mentioned above. For example, the configuration according to the present invention can be adopted as long as the driving tool has a gear that meshes directly with the first gear at the tip of the output shaft of the motor (directly cut). By adopting the configuration according to the invention for the drive tool, it is possible to obtain the same effect as that shown in the embodiment.

It is side sectional drawing which shows the hammer drill which concerns on this Embodiment. It is the figure which showed the assembly | attachment state of the motor with respect to an inner housing, Comprising: (a) shows the expansion | deployment perspective view, (b) has shown the expansion | deployment side view. It is a side sectional view showing a state where a motor, an inner housing, an intermediate shaft, a clutch, a boss, a connecting arm, and a piston cylinder are assembled. It is side sectional drawing which shows schematic structure in the conventional hammer drill.

Explanation of symbols

1, 40 ... Hammer drill (drive tool)
2 ... body housing 3 ... motor 3a ... rotor 4, 41 ... (motor) output shaft 4a, 54 ... gear 6 ... inner housing 6a ... output shaft openings 7, 8, 9, 14, 53 ... ball bearing 11, 43 ... intermediate shafts 13, 42 ... first gear (gear)
DESCRIPTION OF SYMBOLS 15 ... Bush 16 ... Slide bearing 18, 46 ... Cylinder 18a, 52 ... Piston cylinder 20, 45 ... Bit 21, 44 ... 2nd gear 22, 48 ... Boss 25, 49 ... Connection arm 25a ... Arm tip 26, 50 ... Clutch 27 ... striker 28 ... steel ball 29 ... meson 30 ... air chamber 33 ... cooling fan 33a ... (end of cooling fan) front end 34 ... plate 34a ... (plate) opening 36 ... sleeve 37 ... oil seal 38 ... screw

Claims (1)

A ball bearing that rotatably supports the output shaft of the motor;
A gear meshing with a gear formed directly with respect to the tip of the output shaft;
An intermediate shaft that meshes with the gear and is driven to rotate as the output shaft rotates;
Rotation driving means for rotating the bit installed at the tip of the tool as the intermediate shaft rotates,
Impact adding means for applying an impact force to the bit as the intermediate shaft rotates,
A sleeve is fixed to the output shaft so as to cover a part of the gear formed at the tip of the output shaft , and the sleeve is brought into contact with the front portion of the ball bearing,
An oil seal is fitted on an outer peripheral portion of the sleeve so that the sleeve and the oil seal are interposed between the meshing position of the gear and the gear and the installation position of the ball bearing. tool.

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