JP5739271B2 - Impact tool - Google Patents

Description

  The present invention relates to an impact tool such as an impact driver equipped with a brushless motor.

A hitting tool such as an impact driver holds a hammer case that houses a striking mechanism in front of a housing that houses a motor, and projects an anvil forward from the hammer case. The motor uses a brushless motor that eliminates the need for brush replacement, and rotation transmission from the motor to the striking mechanism is, for example, rotation that projects forward through the sensor board as shown in Patent Documents 1 and 2. The rotating shaft of the child is pivotally supported via a ball bearing on a disc-shaped cap that closes the rear surface of the hammer case, and the pinion of the rotating shaft protruding into the hammer case is engaged with the planetary gear held by the spindle. Is going on.
In addition, a fan is fixed to the rear end of the rotating shaft, and after the fan rotates as the motor is driven, outside air is sucked from the intake port provided near the front end of the motor on the side surface of the housing and passed through the motor. The motor can be cooled by exhausting air from an exhaust port provided outside the fan at the rear part of the housing.

JP2011-45201A JP 2010-280033 A

  In such a striking tool, there is a risk that rainwater or the like may enter through the air inlet and the air outlet opening in the housing, and if this reaches the inside of the motor, it may cause failure or deterioration.

  Therefore, an object of the present invention is to provide a striking tool that can prevent the motor from being broken or deteriorated even if rainwater or the like enters from an air inlet or the like by improving the waterproofness of the motor.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a motor housing chamber formed in a rear portion of a housing, a rotor provided with a permanent magnet, and a stator winding having a stator winding on the inner peripheral side. A brushless motor consisting of a child is accommodated, and a fan that sucks outside air into the housing by rotation and ventilates the motor housing chamber is arranged behind the brushless motor, while an impact mechanism is provided in front of the brushless motor. An impact tool in which a cylindrical hammer case from which the rotor's rotating shaft protrudes is arranged, and a partition wall that divides the rotor and the stator winding is provided around the entire circumference of the stator. The front end of the partition wall is closed against the closing plate through which the rotating shaft passes by closing the opening on the front side of the stator, while the rear end of the partition wall is closed with the rear partition wall. In the through hole of the rotating shaft, -A cap that is formed on the cap that closes the opening on the rear side of the case and is fitted with a receiving tube that supports the rotating shaft, and the outside air sucked into the housing by the rotation of the fan It is characterized in that only the gap is allowed to pass.
According to a second aspect of the present invention, in the configuration of the first aspect, the receiving tube is provided with an overlap portion that is formed in a diameter larger than a fitting portion with the through hole and contacts the front surface of the closing plate. It is a feature.
According to a third aspect of the present invention, there is provided a brushless motor comprising a stator having a stator winding, a rotor rotatable with respect to the stator and having a permanent magnet, and the brushless motor accommodated therein And a housing having an intake port and an exhaust port, wherein a partition wall for partitioning the stator and the rotor is provided, and the rear end of the partition wall is a rear partition wall. The outside air that has been closed and sucked from the intake port is allowed to pass through the inside of the stator so as not to enter the rotor side.

ADVANTAGE OF THE INVENTION According to this invention, the waterproofness of a motor can be improved and even if rainwater etc. permeate from the inlet port etc. which were provided in the housing, the failure and deterioration of a motor can be prevented suitably.
According to the second aspect of the present invention, in addition to the effect of the first aspect, the sealing performance between the closing plate and the receiving tube is enhanced, and the intrusion of rainwater and the like from here can be more reliably prevented.

It is a longitudinal cross-sectional view of an impact driver. (A) is an AA line sectional view, (B) is a BB line sectional view. It is the C section enlarged view of FIG. It is a side view of an impact driver. It is a longitudinal cross-sectional view of the example of a change of an impact driver. It is a longitudinal cross-sectional view of an impact driver in a state where a fan housing portion is removed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of an impact driver which is an example of an impact tool. The impact driver 1 accommodates a motor 5 in the rear (the right side in FIG. 1 is the front) and extends a handle 3 below. A housing 2 and a hammer case 4 which is assembled in front of the housing 2 and accommodates the striking mechanism 6 are provided. As shown in FIG. 2, the housing 2 is formed by assembling a pair of left and right halved housings 2a and 2b and screwing them together. The hammer case 4 is a bell-shaped cylinder whose rear portion is sandwiched between the half housings 2a and 2b and whose front portion is tapered forward, and the front portion includes a synthetic resin cover 7 and a rubber-made cylinder. A bumper 8 is attached. A battery pack (not shown) serving as a power source is attached to the lower end of the handle 3, while a switch 9 for projecting the trigger 10 forward is housed on the base side of the handle 3.

  The motor 5 includes a rotor 11 provided with a rotating shaft 12 and a permanent magnet 13 and six teeth 15, 15.. This is a brushless motor that is formed of a cylindrical stator 14 that is wound and through which the rotor 11 passes. The stator 14 of the motor 5 is shown in FIG. 2 by ribs 18, 18... Projecting in the circumferential direction on the inner surfaces of the half housings 2 a and 2 b in the motor housing chamber 17 formed at the rear of the housing 2. As shown to (A), it is supported in the state which formed the clearance gap between the inner surfaces of the housing 2. As shown in FIG. A sensor board 19 as a closing plate provided with a magnetic sensor for detecting the position of the magnetic pole of the rotor 11 is attached to the front end of the stator 14 to close the front end of the stator 14. A through hole 20 through which the rotary shaft 12 passes is formed at the center of the shaft.

  Further, in the stator 14, as shown in FIG. 2 (B), the protruding ends of adjacent teeth 15, 15 are connected to each other, and fixed to the axial center side of the stator windings 16, 16,. A partition wall 21 that partitions between the child winding 16 and the permanent magnet 13 of the rotor 11 is formed over the entire circumference. The front end of the partition wall 21 contacts the rear surface of the sensor substrate 19 over the entire circumference, and the rear end is sealed by a rear partition wall 22 through which the rotary shaft 12 passes. As a result, the rotor 11 is surrounded by the partition wall 21 and the rear partition wall 22 in the motor housing chamber 17. On the other hand, on the stator 14 side, a plurality of notches 23, 23... Are formed at predetermined intervals in the circumferential direction at the front end of the stator 14, and formed between the teeth 15, 15 inside the stator 14. .. Are communicated with the outside of the stator 14.

  Reference numeral 25 denotes a disc-like cap attached to the rear opening of the hammer case 4. In the center, two receiving cylinders 26, 27 having a diameter gradually decreasing toward the rear are formed. 4 and the motor 5 are held by a front wall 28 that partitions the motor 5. A flange 29 projecting in the radial direction is provided between the receiving tubes 26 and 27, and the flange 29 engages with a groove 30 formed in the front wall 28, so that the hammer case 4 is moved in the front-rear direction. Positioning with. The rotating shaft 12 of the motor 5 passes through the receiving cylinders 26 and 27, is supported by the receiving cylinder 27 via the ball bearings 31, and a pinion 32 fitted in the front end is provided in the hammer case 4. It protrudes inside 33.

  Further, as shown in FIG. 3, the rear end of the receiving tube 27 extends until it reaches the inside of the through hole 20 of the sensor substrate 19, and the outer peripheral surface penetrates through the through hole 20 on the outside thereof. A flange portion 34 that is in contact with the inner peripheral surface of the hole 20 is provided. The flange portion 34 is formed to have a thickness that protrudes to the front side of the sensor substrate 19, and an overlap portion 35 that is in contact with the front surface of the sensor substrate 19 is provided on the outer periphery of the front side. An O-ring 36 that is in contact with the front surface of the sensor substrate 19 is held on the rear surface of the overlap portion 35 to seal between the sensor substrate 19 and the overlap portion 35.

A fan accommodating portion 37 is provided behind the motor accommodating chamber 17 in the housing 2. The rotating shaft 12 protruding into the fan housing portion 37 is pivotally supported by a ball bearing 38 provided at the rear portion of the fan housing portion 37, and a fan 39 is fixed to the front side of the ball bearing 38.
Further, as shown in FIG. 4, a plurality of air inlets 40, 40... Are formed on the side surface of the housing 2 so as to contact the outside from the sensor substrate 19 to the stator 5, while the fan housing portion 37. , A plurality of exhaust ports 41, 41... Are formed at positions corresponding to the outside of the fan 39.

On the other hand, in the hammer case 4, the spindle 33 has two planetary gears 44, 44 supported at the rear end thereof by a ball bearing 42 held by the receiving cylinder 26 and held by a carrier portion 43 provided in front thereof. It is meshed with the pinion 32 of the rotating shaft 12. 45 is an internal gear.
The striking mechanism 6 includes a hammer 50 mounted on the front end of the spindle 33, and a coil spring 52 having a front end inserted in a ring groove 51 formed on the rear surface of the hammer 50. It is connected with the spindle 33 via balls 53 and 53 fitted between them. This connection is formed in the inner peripheral surface of the hammer 50 so as to be recessed from the front end toward the rear and the rear end is tapered, and in the outer peripheral surface of the spindle 33, the front end is recessed forward. This is done by fitting the balls 53, 53 across the V-shaped cam groove 55. The hammer 50 is urged by a coil spring 52 to a forward position where the ball 53 is positioned at the rear end of the mountain-shaped cam groove 54 and the front end of the V-shaped cam groove 55.

Reference numeral 56 denotes an anvil. The anvil 56 is pivotally supported by a bearing 57 held at the front end of the hammer case 4, and has a small diameter portion 59 projecting from the front end of the spindle 33 in a bearing hole 58 formed in the rear axis. Is fitted. In addition, a pair of arms 60, 60, which are engaged with a claw (not shown) projecting from the front surface of the hammer 50 in the rotational direction, extend radially at the rear end of the anvil 56 in the hammer case 4.
Further, a bit insertion hole 61 (not shown) is formed at the front end of the anvil 56 protruding from the hammer case 4, and a ball 63 and a sleeve 64 for retaining the bit inserted into the insertion hole 61 are attached. A provided chuck mechanism 62 is provided.

  In the impact driver 1 configured as described above, when the motor 10 is driven by pushing the trigger 10, the rotation of the rotary shaft 12 is transmitted to the spindle 33 via the planetary gears 44, 44 to rotate the spindle 33. . Since the spindle 33 rotates the hammer 50 via the balls 53 and 53 and rotates the anvil 56 with which the hammer 50 is engaged, the spindle 33 can be tightened with a bit attached to the tip of the anvil 56. When the tightening of the screw is advanced and the torque of the anvil 56 is increased, the ball 50 is rolled along the cam grooves 55 and 55 so that the hammer 50 rotates relative to the spindle 33 while rotating the coil spring 52. Retreat against the bias. When the claws of the hammer 50 are disengaged from the arms 60, 60 of the anvil 56, the hammer 50 is rotated by the balls 53, 53 rolling toward the tips of the cam grooves 55, 55 by the bias of the coil spring 52. While moving forward. Therefore, the claw is again engaged with the arms 60 and 60 to generate a rotational impact force (impact). Retightening is performed by the hammer 50 repeating this engagement / disengagement with the anvil 56.

On the other hand, when the fan 39 is rotated together with the rotating shaft 12 by driving the motor 5, outside air is sucked from the air inlet 40 of the housing 2 and enters the gap between the housing 2 and the stator 14. This outside air enters the inside of the stator 14 from the notch 23 of the stator 14, passes through the slots 24, 24... As it is, flows backward, reaches the fan accommodating portion 37, and is discharged from the exhaust port 41 to the outside. The The stator winding 16 is cooled by this air flow.
Here, even if rainwater or the like enters from the intake port 40 or the exhaust port 41, the rotor 11 is covered by the partition wall 21 and the rear partition wall 22 on the motor 5 side, so that rainwater or the like moves to the rotor 11 side. There is no infiltration. Further, even if rainwater or the like wraps around the front side of the sensor substrate 19, since the space between the sensor substrate 19 and the flange portion 34 of the receiving tube 27 is also sealed, the rainwater or the like is on the rotor 11 side or the receiving tube 27. There is no intrusion.

Thus, according to the impact driver 1 of the said form, the partition wall 21 which partitions off between the rotor 14 and the stator coil | winding 16 is provided in the inner periphery of the stator 14 of the motor 5 over the perimeter. The front end of the partition wall 21 is closed against the sensor substrate 19 through which the rotary shaft 12 passes by closing the front opening of the stator 14, while the rear end of the partition wall 21 is closed with the rear partition wall 22, A rotation of the fan 39 is caused by fitting a receiving cylinder 27 formed on a cap 25 that closes the opening on the rear side of the hammer case 4 into the through hole 20 of the rotating shaft 12 in the sensor substrate 19 to support the rotating shaft 12. By allowing the outside air sucked into the housing 2 from the intake port 40 to pass only between the stator windings 16 on the outside of the partition wall 21, the waterproof property of the motor 5 is improved, and the intake port 40 and the like are Because of the motor 5 even if rainwater enters. The deterioration and can be suitably prevented.
In particular, here, since the flange portion 34 of the receiving tube 27 is provided with an overlap portion 35 that is formed to have a diameter larger than the fitting portion with the through hole 20 and abuts against the front surface of the sensor substrate 19, the sensor substrate 19. And the receiving tube 27 are improved in sealing performance, and it is possible to more reliably prevent intrusion of rainwater and the like from here.

In the above embodiment, the sensor substrate is used as the closing plate. However, depending on the position and shape of the sensor substrate, a separate closing plate is provided to close the front side of the stator without using the sensor substrate. Also good.
In addition, in the above embodiment, the flange of the receiving tube is made thicker than the closing plate in the above embodiment, but the overlap portion may be omitted or the inner portion of the closing plate may be omitted. It can be changed as appropriate, for example, by providing a stepped portion around the periphery and joining it with the receiving tube. Further, depending on the size or the like of the through hole, the flange portion may be omitted and the rear end of the receiving cylinder may be directly fitted into the through hole.

  On the other hand, in the above embodiment, the fan 39 is provided on the rotary shaft 12 protruding from the fan housing portion 37, but the fan housing portion 37 is formed separately from the housing 2 as in the impact driver 1A shown in FIG. The rear of the housing 2 is closed with the rear plate 46, while the front of the fan housing portion 37 is closed with the front plate 65, so that the fan housing portion 37 can be screwed to the housing 2 from behind. Accordingly, here, the rear end of the rotary shaft 12 is kept in the motor housing chamber 17, the bearing receiving portion 47 is formed inside the rear partition wall 22, and the rotary shaft 12 is held by the ball bearing 48 held by the bearing receiving portion 47. The rear end is pivotally supported.

  In the fan housing portion 37, a bearing receiving portion 66 is formed on the rear surface of the front plate 65, and the ball bearing 67 is held by the bearing receiving portion 66, and the ball bearing 67 and the rear ball bearing 38 serve as a fan. The front and rear ends of the fan shaft 68 to which 39 is fixed are pivotally supported. In the rear plate 46 and the front plate 65, a plurality of through holes 69, 69,... Located behind the slot 24 of the motor 5 are formed, and the slot 24 and the fan accommodating portion 37 are communicated to allow passage of outside air. It is possible.

In this way, if the fan accommodating portion 37 is removed, the overall length in the front-rear direction becomes shorter and compact as shown in FIG. 6, so when not working continuously for a long time or when working in a narrow place. May be used by arbitrarily removing the fan housing portion 37. In this case, the through hole 69 of the rear plate 46 serves as an exhaust port.
However, providing the fan 39 on the fan shaft 68 separate from the rotary shaft 12 requires a drive source for rotating the fan shaft 68. This is because, for example, a fan motor is newly provided in the fan accommodating portion 37 to transmit the rotation to the fan shaft 68 via a gear or the like, and the fan accommodating portion 37 is electrically connected to the rear plate 46 and the front plate 65. Terminals (contact type, plug-in type, etc.) that are connected to each other may be provided to obtain power from the battery pack. If the distance between the fan and the rotor is short, a permanent magnet or a magnetic material corresponding to the permanent magnet of the rotor is provided on the front surface of the fan, and the fan is rotated synchronously by the attractive force of the permanent magnet of the rotor. It is also possible.

  1, 1A-Impact driver, 2-Housing, 3-Handle, 4-Hammer case, 5-Motor, 6-Blow mechanism, 11-Rotor, 12-Rotary shaft, 13- Permanent magnet, 14 .. Stator, 15 .. Teeth, 16 .. Stator winding, 17 .. Motor housing chamber, 19 .. Sensor board, 20 .. Through hole, 21 .. Partition wall, 22. Rear partition wall, 23, notch, 24, slot, 25, cap, 26, 27, receiving cylinder, 31, 38, 42, 48, 67, ball bearing, 33, spindle, 34, ... Flange part, 35 .. Overlap part, 37 .. Fan housing part, 39 .. Fan, 40 .. Inlet port, 41 .. Exhaust port, 46 .. Rear plate, 47, 66. ..Hammer, 52 ... Coil spring, 53 ... Lumpur, 56 ... anvil, 60 ... arm, 68 ... fan shaft, 69 ... through hole.

Claims (3)

A motor housing chamber formed in the rear part of the housing accommodates a brushless motor including a rotor provided with a permanent magnet and a stator having a stator winding on the inner peripheral side, and behind the brushless motor. In addition, a fan that sucks outside air into the housing by rotation and vents the motor housing chamber is disposed, while a striking mechanism is provided in front of the brushless motor, and a rotating shaft of the rotor projects. An impact tool with a hammer case,
A partition wall for partitioning between the rotor and the stator winding is provided over the entire circumference on the inner periphery of the stator, and the front end of the partition wall is closed off the opening on the front side of the stator. The rear end of the partition wall is closed with a rear partition wall,
In a through hole of the rotary shaft in the closing plate, a cap that is formed on a cap that closes an opening on the rear side of the hammer case and fits a receiving cylinder that supports the rotary shaft,
An impact tool characterized in that the outside air sucked into the housing by the rotation of the fan is allowed to pass only between the stator windings outside the partition wall.   The impact tool according to claim 1, wherein the receiving cylinder is provided with an overlap portion that is formed to have a larger diameter than a fitting portion with the through hole and abuts against a front surface of the closing plate. A brushless motor comprising: a stator having a stator winding; and a rotor rotatable relative to the stator and having a permanent magnet;
A housing that houses the brushless motor and has an intake port and an exhaust port,
Providing a partition wall for partitioning between the stator and the rotor and closing the rear end of the partition wall with a rear partition wall ;
An electric tool characterized in that the outside air sucked from the air intake port does not enter the rotor side through the inside of the stator.

Images