JP6855096B1 - Electric tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric tool capable of suppressing the generation of sound during work, stabilizing the rotation of a drive shaft, and dissipating heat generated during operation. A transmission mechanism is provided for transmitting the axial rotational force of a spindle 4 that is axially rotated by driving a motor 3 to a tip tool bit 300. A heat dissipation space 60 is formed between the motor 3 and the transmission mechanism, and at least a part of the surface of the spindle 4 is exposed in the heat dissipation space 60. A regulating member 8 is mounted on the exposed surface of the spindle 4 to dissipate the heat of the spindle 4 to the heat dissipation space without hindering the axial rotation of the spindle 4 and to regulate the displacement of the transmission mechanism in the motor direction. There is. [Selection diagram] Fig. 1

Description

The present invention relates to a drill driver type power tool used for interior work or exterior work of a building.

As a drill driver type power tool, for example, the rotary impact tool described in Patent Document 1 is known. This rotary impact tool has a striking mechanism that makes it easier to loosen by giving a rotary impact with a hammer to a screw that is almost integrated with the screw hole due to rust etc. and is difficult to loosen, and a striking stop mechanism that prevents the movement of the hammer. Be prepared. When the striking mechanism is activated, the rotary impact tool can be used as an impact driver, while when the striking stop mechanism is activated, the rotary impact tool can be used as an electric drill without a striking sound.

Further, the power tool described in Patent Document 2 physically has one of a mode of operating as an impact driver, a mode of operating as a vibration drill, a mode of operating as a drill without vibration, and a clutch mode of using a clutch mechanism. It is configured so that it can be selected using the operation mechanism.

Japanese Unexamined Patent Publication No. 6-182674 Japanese Unexamined Patent Publication No. 2013-35090

In the interior work or exterior work of a building, like an impact driver, the sound generated when metals collide with each other when a hammer hits a hit part, that is, the loudness of the hitting sound and the frequency of its occurrence have a significant effect on the construction period. To exert. This is because the hours and days of the week when the use of such power tools is permitted are limited. For the rotary impact tool disclosed in Patent Document 1 and the power tool disclosed in Patent Document 2, an operation mode other than the impact driver can be selected, but due to an erroneous mode selection by an operator (operator) or the like. It may generate a striking sound.

Further, in order to enable each tool described in Patent Documents 1 and 2 to be used as a plurality of tools by one unit, parts for all the tools are arranged in a limited storage space of the housing. Therefore, the inside of the housing is dense. In electric tools that use a motor as a drive source, the amount of heat generated by the electric tool has increased due to the recent increase in the output of the motor, and a cooling fan may be provided. There is a problem that the cooling air does not hit the existing parts sufficiently and it cannot be cooled effectively.

An object of the present invention is to provide an electric tool capable of efficiently dissipating heat generated during operation without causing collision between metals. Other objects of the present invention will become clear from the examples of embodiments described later.

An electric tool according to an embodiment of the present invention is an electric tool including a motor, a spindle that rotates the shaft by driving the motor, and a transmission mechanism that transmits the axial rotational force of the spindle to the tip tool bit. Therefore, a heat dissipation space is formed between the motor and the transmission mechanism, and at least a part of the surface of the spindle is exposed in the heat dissipation space, and the exposed surface of the spindle is covered with the above. It is characterized by being equipped with a regulating member that dissipates the heat generated in the spindle to the heat dissipation space without hindering the shaft rotation of the spindle and regulates the displacement of the transmission mechanism in the motor direction during operation. To do.

According to the power tool of the present invention, it is possible to provide a power tool capable of efficiently dissipating heat generated during operation.

The structural explanatory view of the power tool which concerns on 1st Embodiment of this invention. The structural explanatory view of the brushless motor used in this embodiment. Structural explanatory view which shows the engagement state of anvil and a hammer member. The external perspective view which shows the structural example of the regulation member. (A) and (b) are cross-sectional views showing other structural examples of the regulating member. FIG. 5 is a cross-sectional view showing another shape example of the regulating member. FIG. 5 is a cross-sectional view showing another shape example of the regulating member. The schematic diagram which shows the state which the fan is attached and fixed to the motor shaft. The structural explanatory view of the power tool which concerns on 2nd Embodiment of this invention. (A) and (b) are state explanatory views of the spirit level in the second embodiment. (A) and (b) are state explanatory diagrams of spirit levels having other configurations.

[First Embodiment]
FIG. 1 is a structural explanatory view of a power tool according to the first embodiment of the present invention. For convenience, the XYZ orthogonal three-dimensional axes are set in the figure. The Z-axis represents the height direction, the X-axis represents the front-rear direction, and the Y-axis represents the width direction. The electric tool 1 is used as a tightening tool for screws or the like, and includes a housing 2 as an exterior material. Inside the housing 2, a motor 3, a spindle 4, and a shaft rotational force transmission mechanism 5 are provided. Contains various electrical materials.

The housing 2 is made of hard resin having a size that can be operated by an operator with one hand, and has a pair of covers 20 and a grip portion 21. A plurality of partitions are formed inside each of the pair of covers 20, and by fixing them with screws facing each other, parts such as the motor 3 are accommodated in the parts space defined by each partition. It has become so. A plurality of ventilation holes 201 are formed at the rear end (−X direction) of the housing 2 that is on the operator side during work, and an exhaust hole 202 is formed at the front end (+ X direction) of the housing 2. This is to prevent the air discharged from the exhaust hole 202 from directly hitting the operator.

The grip portion 21 is formed in a size and shape that can be gripped by an operator, and a battery pack 7 is detachably attached to the lower end portion thereof. Inside the grip portion 21, a control board 100 that performs a power control function, an electronic clutch control function, a motor control function, and the like, which will be described later, is fixed. The electric power (amplitude value: zero value when the battery pack 7 is in the detached state) V1 supplied from the battery pack 7 to the motor 3 and the rotational torque detection signal S10 described later from the motor 3 are input to the control board 100. .. Further, the drive power (amplitude value) V2 and the command signal S11 described later are output from the control board 100 to the motor 3.

The motor 3 is a component that serves as a rotational drive source for the power tool 1. In this embodiment, an example in which a brushless motor having a calorific value generally smaller than that of a DC motor is used will be described. That is, as shown in FIG. 2, the motor 3 used in the present embodiment is a brushless motor including a rotor (rotor) 31 and a stator (stator) 32. The rotor 31 includes a magnet and rotates integrally with the motor shaft 33. A rotational torque sensor 34 is provided on the motor shaft 33. The rotational torque sensor 34 is a sensor that detects the rotational torque generated when the motor shaft 33 is driven, and outputs the above signal S10 representing the detection result to the control board 100.

The stator 32 is fixed to a predetermined internal partition portion of the housing 2, and the rotor 31 is rotatably arranged inside the stator 32. A motor bearing portion 35 is provided in front of the rotor 31. The motor bearing portion 35 supports the front portion of the motor shaft 33. The motor shaft 33 projects further forward from the motor bearing portion 35 by a predetermined length.

The spindle 4 is a shaft rotating body that rotates around the shaft by driving the motor 3. As described above, since the motor shaft 33 projects forward from the motor bearing portion 35, the spindle 4 is connected to the end portion of the motor shaft 33, so that the spindle 4 rotates in conjunction with the operation of the motor 3.
The spindle 4 has a metal columnar portion 41 and an engaging protrusion 42 formed at an end opposite to the motor shaft 33. The engaging projection 42 is integrally formed with the columnar portion 41, extends symmetrically around the columnar portion 41, and the outer peripheral portion is formed in an arc shape. The engaging projection 42 is connected to the engaging mechanism of the transmission mechanism 5. The connection mode between the motor shaft 33 and the spindle 4 and the connection mode between the engagement protrusion 42 of the spindle 4 and the engagement mechanism of the transmission mechanism 5 are well known in electric tools having this type of spindle 4, respectively. Therefore, the specific description thereof will be omitted. The outer diameter of the columnar portion 41 of the spindle 4 is larger than that of the motor shaft 33 and smaller than that of the portion where the connecting mechanism at both ends is present.

In the power tool 1 of the present embodiment, the heat dissipation space 60 is formed inside the housing 2 between the motor 3 and the transmission mechanism 5. The heat dissipation space 60 is located between the motor 3 facing the side view (viewpoint from the Y axis) and the transmission mechanism 5 (hammer member 51 in this example) having the surface of the columnar portion 41 of the spindle 4 as the bottom surface. It is a three-dimensional space formed concavely from a two-dimensional viewpoint. Since the spindle 4 is made of metal, the heat generated by the motor 3 or the like is dissipated from the exposed portion of the motor shaft 33 and the surface of the columnar portion 41 of the spindle 4 to the heat dissipation space 60. Then, the air flowing in from the ventilation hole 201 of the housing 2 circulates in the heat dissipation space 60 and is immediately dissipated from the exhaust hole 202 to the outside. Therefore, not only the spindle 4 but also the inside of the housing 2 generates heat, or the temperature rise of the portion where heat is transferred through other parts is suppressed. Further, since the columnar portion 41 of the spindle 4 is exposed, it is possible to easily observe whether or not the spindle 4 is deformed and whether or not the drive system for shaft rotation is operating normally.

The shaft rotational force transmission mechanism 5 includes a hammer member 51 elastically connected to the engaging protrusion 42 of the spindle 4 via a spring 55, and an anvil 53 which is an example of a bit holding mechanism for holding the tip tool bit 300. Consists of including. The anvil 53 is a known tool component having a chuck hole 52 for holding the tip tool bit 300 so as to be detachable, so that the rotation axis thereof coincides with the rotation axis of the motor shaft 33 and the rotation axis of the hammer member 51. Is placed in. The reason why the spindle 4 and the hammer member 51 are elastically connected via the spring 55 is to absorb the stress generated when the screw or the like is tightened by the tip tool bit 300 so as not to damage the screw or the like.

At the end of the anvil 53 opposite to the chuck hole 52, a first engaging portion 531 extending symmetrically with respect to the rotation axis of the anvil 53 and a second engaging portion 532 are formed. There is. Further, at the end of the hammer member 51 on the anvil 53 side, a first recessed portion 511 accommodating the first engaging portion 531 and a second recessed portion 512 accommodating the second engaging portion 532 are formed. There is.

For the hammer member 51, for example, a portion of the hammer body having a higher specific gravity than other members among the striking mechanisms of commercially available impact tools can be extracted and used. The hammer member 51 is made of substantially columnar steel, and its diameter is more than twice that of the columnar portion 41 of the spindle 4. Further, the tip tool bit 300, which will be described later, is attached at a position as close as possible to the base end portion thereof so as to be rotatable around the central axis (rotation axis).
Although the power tool 1 of the present embodiment is not an impact tool, the inertial force at the time of shaft rotation can be increased by using a hammer member for an impact tool having a relatively high specific gravity. That is, for example, when the rotation center axis of the tip tool bit 300 tries to deviate from the rotation center axis of the motor 3 or the spindle 4, a force (torque) that tries to rotate around the rotation center axis is generated by an inertial force, and during driving. The shaft rotation speed can be kept stable (the so-called coma keeps rotating stably).

In the power tool 1 of the present embodiment, the regulation member 8 is mounted on the surface of the columnar portion 41 of the exposed spindle 4 in the heat dissipation space 60 described above. During operation, the stress of the tip tool bit 300 causes displacement of the transmission mechanism 5, particularly the hammer member 51, in the direction of the motor 3. The regulating member 8 is a member (so-called spacer) for regulating this displacement to a certain amount or less without hindering the rotation of the spindle 4, but in the present embodiment, the heat generated in the pillar portion 42 of the spindle 4 is applied. It also has the role of dissipating to the heat dissipation space 60. The regulating member 8 is composed of a heat conductive material, for example, a pair of steel gutters manufactured by a mold facing each other. However, if the thermal conductivity is not impaired, it may be formed of a hard resin material. When the regulating member 8 is made of steel, the mechanical strength of the spindle 4 can be reinforced to suppress fluctuation (swing) of the rotation axis.

The length of the regulating member 8 in the X direction is slightly smaller than the length of the columnar portion 41 of the spindle 4 exposed in the heat dissipation space 60. This is to positively allow a slight displacement of the transmission mechanism 5 (hammer member 51). That is, the length of the regulating member 8 in the X direction is the distance (length) between the hammer member 51 and the motor bearing 33 when the spring 55 is urged to allow displacement by the spring 55. Further, the total width of the regulating member 8 when deployed on a flat surface is substantially the same as the outer diameter of the columnar portion 41 of the spindle 4.

The regulating member 8 is mounted so as to be replaceable. Therefore, as shown in FIG. 4, for example, a pair of gutters 81 having the same shape and size are put on the outer circumference of the columnar portion 41 of the spindle 4, and then each gutter 81 is fixed with a fastener. The pair of ends 811 and 813 of one gutter 81 are molded into a shape that engages with the pair of ends 812 and 814 of the other opposite gutter 81.

As shown in FIGS. 5 (a) and 5 (b), the regulating member 8 also aggregates a plurality of spacer parts 81a to 81j that are in contact with the surface of the columnar portion 41 of the spindle 4, and attaches them to each other. Or it may be fixed by wrapping a fastener, for example, a metal tape 85 or the like after positioning.

Alternatively, the regulating member 8 may be composed of the linear or rod-shaped conductor 86 illustrated in FIG. 6, and the conductor 86 may be wound around the surface of the spindle 4 and fixed with bolts and nuts. Further, as shown in FIG. 7, the regulating member 8 may be composed of heat radiation fins 87 having an arcuate base portion, and the heat radiation fins 87 may be put on or attached to the surface of the spindle 4. In the regulation member 8 of the shape example of FIGS. 6 and 7, the contact area between the heat transmitted through the surface of the columnar portion 41 of the spindle 4 and the heat dissipation space 60 is significantly increased as compared with the case without them. The heat dissipation effect can be further enhanced.

Next, the control board 100 provided inside the grip portion of the housing 2 will be described with reference to FIGS. 1 and 8. The control board 100 is provided with a power control circuit 101, a motor control circuit 102, an electronic clutch control circuit 103, and the like on an insulating board. The power control circuit 101 monitors the power V1 output from the battery pack 7, and outputs an alarm signal or the like when the power V1 drops below a predetermined value. Further, the electric power V1 supplied from the battery pack 7 is partially depressurized and supplied to the active elements of the motor control circuit 102 and the electronic clutch control circuit 103.

The motor control circuit 102 supplies electric power V2 of a predetermined set level to the motor 3 by a power-on operation of an operation panel (not shown) provided at a predetermined portion of the housing 2, and power-off operation or an electronic clutch control circuit 103 described later. The supply of electric power V2 to the motor 3 is stopped by the command signal S11 of.

The electronic clutch control circuit 103 acquires the electric power when the motor control circuit 102 drives the motor 3 and the rotational torque detected by the rotational torque sensor 34 when the electric power is supplied. Then, it is determined whether or not these acquired rotational torques have reached the torque set values set in advance on the operation panel or the like, and when they have reached, the power supply to the motor 3 is stopped to the motor control circuit 102. Command signal S11 is output. As a result, the motor 3 stops rotating, so that the transmission of the rotational driving force from the transmission mechanism 5 to the tip tool bit 300 is stopped.
That is, the mechanical clutch function of idling the motor when the rotational torque reaches the torque set value and preventing the rotational driving force from being transmitted to the tip tool bit 300 is realized by electrical control. Therefore, it is possible to realize a clutch function without collision between metal parts.

The torque set value can be arbitrarily set by the operator and changed as appropriate. Since the setting and change of the set value is realized not by switching the mechanical mechanism but by electrical control, it can be easily realized.

[Second Embodiment]
A second embodiment of the present invention will be described. FIG. 9 is a structural explanatory view of the power tool 1 ′ according to the second embodiment. The power tool 1'is fixed by covering the outer surface of the housing 2 of the power tool 1 of the first embodiment with the sub-housing 9. Other components are the same as those of the power tool 1 of the first embodiment. Therefore, the elements described in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The sub-housing 9 is made of hard resin and is provided with a guide mechanism on a side surface portion. The guide mechanism includes a linear guide wire 91 and a spirit level 92 that coincide with the rotation center axis in a side view. The guide wire 91 is used to guide the operator (operator) in the positioning when the tip tool bit 300 is attached and the direction in which a force is applied during the work (direction of the rotation center axis).

The spirit level 92 is a device for confirming the angle of the center axis of rotation with respect to the horizontal, and is a glass container filled with a liquid. As shown in FIG. 10A, when the power tool 1'is tilted downward to the right, the water surface 921 is tilted to the right, and when the power tool 1'is tilted downward to the left, FIG. As shown in b), the water surface 921 also falls to the left. Therefore, the angle of the power tool 1'with respect to the current horizontal plane can be known.

Alternatively, instead of the spirit level 92, a spirit level 93 containing a liquid with bubbles remaining may be used. In this level 93, when the power tool 1'is tilted downward to the right, the bubble 931 moves to the upper left and the power tool 1'is tilted downward to the left, as shown in FIG. 11 (a). In this case, the bubble moves to the upper right as shown in FIG. 11 (b). Therefore, the angle of the power tool 1'with respect to the current horizontal plane can be known at the position of the bubble 931.

Such spirit levels 92 and 93 are used, for example, when screwing or loosening a screw horizontally with respect to a building.
Since the spirit levels 92 and 93 are not indispensable, the guide mechanism can be configured only by the guide wire 91. In this case, not only one guide wire 91 but also a plurality of guide wires 91 having different angles may be provided.
Further, a ventilation hole or an exhaust hole may be formed in the sub-housing 9.

[Modification example]
Although one embodiment of the present invention has been described above, the present invention can be carried out in various aspects. For example, in the present embodiment, an example in which the hammer member 51 and the engagement mechanism 42 of the spindle 4 are elastically connected by a spring 55 has been described, but the regulation member 8 is used to electrically connect the hammer member 51 with the first engagement portion 531 of the anvil 53. A known clutch mechanism may be used in which the operation of the portion 532 is restricted to the extent that the portion 532 does not separate from the first recessed portion 511 and the second recessed portion 512 of the hammer member 51.

Further, in the present embodiment, an example in which the rotational torque sensor 34 is provided on the motor shaft 33 has been described, but it may be provided near the surface of the spindle 4, the regulating member 8, or the base end of the anvil 53.

Further, the fan may be mounted and fixed in the vicinity of the heat radiating space 60 in the housing 2 or in a portion of the housing 2 facing the heat radiating space 60. As a result, the motor 3 and the like can be cooled more efficiently in combination with the air circulation action from the ventilation hole 201 at the rear end to the exhaust hole 202 at the front end inside the housing 2.

Although the description has been made on the premise that the tip tool bit 300 is a screwdriver in the present embodiment, the tip tool bit 300 may be a drill.

Claims (6)

An electric tool including a motor, a spindle that rotates the shaft by driving the motor, and a transmission mechanism that transmits the shaft rotation force of the spindle to the tip tool bit.
A space for heat dissipation is formed between the motor and the transmission mechanism.
At least a part of the surface of the spindle is exposed in the heat dissipation space.
Regulations that dissipate heat generated in the spindle to the heat dissipation space and regulate displacement of the transmission mechanism in the motor direction during operation without hindering the axial rotation of the spindle on the exposed surface of the spindle. It is characterized in that the member is mounted,
Electric tool. The heat dissipation space is a three-dimensional space having a bottom surface of the exposed spindle and formed concavely from a two-dimensional viewpoint between the motors facing each other in a side view and the transmission mechanism. To
The power tool according to claim 1. The transmission mechanism includes a hammer member, a bit holding mechanism for holding the tip tool bit, and an elastic connecting member for elastically connecting the hammer member and the bit holding mechanism, and the spindle and the hammer. The rotation center axes of the member and the bit holding mechanism coincide with each other on a straight line.
The power tool according to claim 1 or 2. It further includes a housing that houses the motor, the spindle, and the transmission mechanism, and a sub-housing that is fixed to the outer surface of the housing.
The sub-housing is provided with a guide mechanism including a linear guide line that coincides with the rotation center axis in a side view.
The power tool according to claim 3. It is equipped with a detecting means for detecting the rotational torque of the motor or the tip tool bit.
The transmission mechanism is characterized in that said detecting means to stop the pre-Symbol transmission when it is detected that exceeds a predetermined torque,
The power tool according to any one of claims 1 to 4. A housing for accommodating the motor, the spindle, the transmission mechanism, and the bit holding mechanism is provided therein, and a ventilation hole is formed in a rear end portion of the housing that is on the operator side during operation, and the rear portion is described. An exhaust hole is formed at the front end portion opposite to the end portion, and a fan is provided at a portion facing the heat dissipation space, and the air circulated by the fan is exhausted to the outside from the exhaust hole.
The power tool according to claim 3 or 4.

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