JP2008187760A - Motor and impact rotary tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a moment of inertia of a motor with a very simple configuration, while realizing miniaturization and lightweight of the motor. <P>SOLUTION: The motor is provided with a rotor 15, having a rotary shaft 11 and a magnetic circuit member 14, fixed on the rotary shaft 11; a stator 19 having a magnetic circuit; and a cooling fan 30 fixed on the rotary shaft 11. By having the magnetic circuit member 14 of the rotor 15 fixed on the rotary shaft 11 with an iron core 12 having a gap 12a communicating in the rotary shaft direction 11, and a non-magnetic body 70 having high density fixed in the gap 12a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor that realizes miniaturization of a motor and securing a sufficient moment of inertia of a rotor, and an impact rotary tool equipped with the motor.

  The downsizing and weight reduction of motors are being promoted along with higher performance of magnets and method innovation. For example, an impact used for tightening bolts, nuts, screws, etc. by rotating a bit attached to the tip with an impact torque obtained by giving impact (impact) in the rotation direction by a hammer rotated by a motor Also in a rotary tool, in order to improve a user's usability, it is requested | required to mount the motor reduced in size as mentioned above and reduced in weight.

  However, when trying to reduce the size and weight of the motor, it is required to reduce the weight of the rotor core that occupies a large weight in the motor. If the weight of the iron core is reduced, the weight of the rotor is reduced, so that the moment of inertia of the rotor is reduced. Therefore, if a motor that has reduced the moment of inertia in favor of miniaturization and weight reduction is mounted on the impact rotary tool as described above, a large impact torque cannot be obtained, which reduces the performance as a tool. There was a problem such as.

In view of this, a technique has been devised to increase the moment of inertia by inserting a non-magnetic weight into the rotor (rotor) of the motor (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 57-192755

  However, the technique disclosed in Patent Document 1 has a problem that the volume of the rotor is increased and the motor is increased in size.

  Therefore, the present invention has been devised to solve the above-described problems, and increases the moment of inertia of the motor with a very simple configuration while realizing a reduction in size and weight of the motor. It is an object of the present invention to provide a motor capable of performing the above and an impact rotary tool equipped with the motor.

  The motor of the present invention includes a rotor having a rotating shaft and a magnetic circuit member fixed to the rotating shaft, a stator having a magnetic circuit, and a cooling fan fixed to the rotating shaft. The magnetic circuit member is fixed to the rotating shaft by an iron core having a gap communicating in the direction of the rotating shaft, and a non-magnetic material having a high density is fixed in the gap, thereby solving the above-described problem.

  In the motor of the present invention, the non-magnetic material is formed into a shape that can be inserted into the gap, and is fixed by being inserted into the gap.

  Moreover, the motor of the present invention solves the above-mentioned problems by filling the gap in the state of being melted in a viscous state and fixing by solidifying in the gap.

  The impact rotating tool of the present invention has a main rotating member and a driven rotating member, and when the load torque applied to the driven rotating member is small, the main rotating member and the driven rotating member. When the moving member is integrally rotated and the load torque is increased, the main driving side rotating member and the driven side rotating member are once separated and then integrated again by the return means. Impact of applying driving torque impactively by inertial force accompanying rotation of the main rotation side rotation member from the main rotation side rotation member to the driven side rotation member when being integrated again by the return means The above-described problem is solved by mounting the motor according to any one of claims 1 to 3, wherein the main drive side rotation member is rotated in a rotary tool.

  According to the present invention, by utilizing the air gap of the iron core of the magnetic circuit member of the rotor of the motor and fixing the nonmagnetic material with a high density in the air gap, the volume of the rotor is not increased at all. In addition, the moment of inertia can be easily increased with a slight increase in mass, that is, while the motor is reduced in size and weight.

  In addition, according to the present invention, it is possible to form a stator with an improved moment of inertia in a very short working time because only a nonmagnetic material formed into an insertable shape is inserted.

  Further, according to the present invention, it takes time to solidify the non-magnetic material melted in a viscous state, but since the space is filled with the non-magnetic material without gaps, the moment of inertia can be further improved. .

  Furthermore, according to the present invention, a motor with an increased moment of inertia can be mounted on an impact rotary tool with a very simple configuration while realizing a reduction in size and weight. Therefore, the impact rotary tool itself is also reduced in size and weight, so that the user's feeling of use can be enhanced and sufficient impact torque can be applied, and high performance as a tool can be exhibited.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, an impact rotary tool 1 shown as an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a transparent view showing the main components of the impact rotary tool 1.

  As shown in FIG. 1, the impact rotary tool 1 includes a tool main body 2 on which main components are mounted, and a battery unit 3 on which a rechargeable battery for supplying power to the tool main body 2 is mounted. The tool body 2 includes a motor body 10, a cooling fan 30 that cools the motor body 10, a speed reducer 40, an impact block 50 that is an impact torque generation mechanism, and a bit 60. The impact rotary tool 1 pulls the trigger switch 4 so that power is supplied from the battery unit 3 to the motor body 10 to rotate the motor body 10. Then, after the rotational force of the motor main body 10 is decelerated to an appropriate speed by the speed reducer 40 via the rotating shaft 11, it is converted into an impact torque by the impact block 50 and transmitted to the bit 60, and the screw tightening torque. Become.

  Here, the impact block 50 which is an impact torque generating mechanism will be described. The impact torque generating mechanism basically has a main drive side rotating member and a driven side rotary member, and when the load torque applied to the driven side rotary member is small, the main drive side rotary member and the driven side rotating member are provided. When the driving member is integrally rotated and the load torque increases, the main driving side rotating member and the driven side rotating member are once separated and then integrated again by the returning means. This is a mechanism that, when reintegrated, applies a driving torque shockingly from the main driving side rotating member to the driven side rotating member by the inertial force accompanying the rotation of the main driving side rotating member.

  The impact block 50 of the impact rotary tool 1 shown in FIG. 1 has a configuration in which the hammer 51 is used as the main driving side rotation member, the anvil 52 is used as the driven side rotation member, and the spring is used as the return means.

  As shown in FIG. 2 (a), the hammer 51 is a substantially cylindrical member having a striking portion 51a protruding on the surface on the output shaft 55 side, and is driven through a cam mechanism containing a steel ball (not shown). The shaft 54 is rotatably fitted on the shaft 54. The hammer 51 is restricted from moving relative to the drive shaft 54 in the axial direction and moving around the axis by the cam mechanism. As shown in FIG. 2A, the hammer 51 is urged toward the output shaft 55 by a spring 53.

  As shown in FIG. 2 (a), the anvil 52 is a member that includes a ring-shaped base portion 52a connected to the output shaft 55, and a hit portion 52b that protrudes outward from the base portion 52a. In the axial direction, the hit portion 52 b is disposed at a position overlapping the hit portion 51 a of the hammer 51. Thereby, when the hammer 51 rotates, the hitting part 51a of the hammer 51 hits the hit part 52b of the anvil 52 to generate an impact torque.

  As shown in FIG. 2B, when the load (torque) on the output shaft 55 side where the bolts and nuts are mounted is small, the rotational force of the drive shaft 54 is applied to the hammer 51 via a cam mechanism (not shown). Further, it is transmitted to the output shaft 55 through the engagement between the striking portion 51 a of the hammer 51 and the hit portion 52 b of the anvil 52.

  As shown in FIG. 2C, when the load applied to the output shaft 55 is increased, the hammer 51 rotates relative to the drive shaft 54. At this time, the hammer 51 is moved by the cam mechanism (not shown). It moves (retreats) toward the motor body 10 against the urging force, and the engagement between the striking portion 51a of the hammer 51 and the hit portion 52b of the anvil 52 is released. When the hitting part 51a gets over the hit part 52b, the hammer 51 is moved to the output shaft 55 side by the guidance of a cam mechanism (not shown) by the urging force of the spring 53.

  Thereafter, as shown in FIG. 2 (d), the hammer 51 is re-engaged with the hit portion 52b of the anvil 52 by the rotation of the hammer 51, and the hit portion 52b is impacted in the rotational direction. give. The impact block 50, which is an impact torque generation mechanism, transmits the impact torque to the bit 60 by repeating the above operation.

  Thus, although the type using the hammer 51 and the anvil 52 is employ | adopted as the impact block 50, this invention is not limited to this, For example, a magnetic force and a frictional force are utilized as an impact torque generation mechanism. Various types of impact torque generation mechanisms such as a type and a type using a screw mechanism can be used.

  Subsequently, a motor including the motor body 10 and the cooling fan 30 will be described with reference to FIGS. 3 and 4. FIG. 3 is a perspective view showing an entire image of the motor composed of the motor body 10 and the cooling fan 30, and FIG. 4 is a longitudinal sectional view cut so as to pass through the center of the rotating shaft 11 shown in FIG. is there.

  As shown in FIGS. 3 and 4, the motor body 10 is a so-called brushless motor, and includes a rotor 15 and a stator 19.

  The rotor 15 includes a rotating shaft 11, and a magnetic circuit member 14 including an iron core 12 fixed to the rotating shaft 11 by adhesion or press fitting, and a permanent magnet 13 that is inserted into the iron core 12 and generates a magnetic field. Yes. The rotor 15 is rotatably held around the rotation shaft 11 by ball bearings 20A and 20B which are bearings of the rotation shaft 11. A hall element (not shown) for detecting the position of the rotor 15 is provided in the vicinity of the rotor 15.

  The stator 19 includes an iron core 16 and a plurality of coils 18 wound around the iron core 16 via a coil frame 17. A magnetic circuit is formed on the stator 19 by the iron core 16 and the coil 18.

  Such a motor body 10 controls the energization to the coil 18 of the stator 19 based on a position detection signal from a hall element (not shown) by a control circuit (not shown), thereby adjusting the rotation angle of the rotor 15. The rotor 15 is rotated so as to generate a corresponding continuous torque.

  As described above, the motor body 10 is a brushless motor, but the present invention is not limited to such a motor type.

  Next, the cooling fan 30 will be described. As shown in FIG. 4, the cooling fan 30 is fixed to the rotating shaft 11 of the rotor 15 by bonding or press-fitting, and is rotatably held around the rotating shaft 11 together with the rotor 15. By rotating together with this, the magnetic circuit member 14 and the stator 19 of the rotor 15 are cooled.

As shown in FIGS. 3 and 4, the cooling fan 30 has a main surface 31 s directed in the rotation direction of the rotary shaft 11, and radially from the inner peripheral portion 31 </ b> B fixed to the rotary shaft 11 around the rotary shaft 11. It has a plurality of extending wings 31A. As shown in FIGS. 3 and 4, the wing 31 </ b> A extends so as to be larger than the outer shape of the magnetic circuit member 14 of the rotor 15. The cooling fan 30 can be formed of a resin (eg, polyamide (nylon), about 1.1 g / cm ³ ) or the like.

  When the cooling fan 30 having a plurality of blades 31A having such a shape rotates, air flows as shown by an arrow A in FIG. Specifically, when the cooling fan 30 rotates, the air flow draws air so as to pass through the magnetic circuit member 14 along the rotating shaft 11 and finally discharges toward the outer peripheral direction of the cooling fan 30. cause. By causing such an air flow, the air that has cooled the magnetic circuit member 14 and the stator 19 of the rotor 15 can be easily discharged out of the casing of the impact rotary tool 1.

  Next, the magnetic circuit member 14 of the rotor 15 will be described. The motor body 10 is a so-called IPM (Interior Permanent Magnet) motor. As shown in FIG. 6A, the permanent magnet 13 is embedded in the iron core 12 of the magnetic circuit member 14 constituting the rotor 15. It is a motor. As shown in FIGS. 6A and 6B, the iron core 12 of the magnetic circuit member 14 of such an IPM motor is provided with a magnetic resistance in a part of the magnetic circuit to improve the torque performance of the motor. The air gap 12a is intentionally communicated in the direction of the rotation axis 11.

  In the example shown in FIG. 6A, the gaps 12 a exist at both ends where the four permanent magnets 13 are embedded in the vicinity of the outer periphery of the iron core 12 of the rotor 15, and there are a total of eight spaces. The number of gaps 12a is not limited to this, and a plurality of gaps 12a are provided in the iron core 12 of the rotor 15 according to the number and design of the permanent magnets 13 to be embedded.

  In general, the moment of inertia is expressed by the square of mass × radius. Therefore, by utilizing the gap 12a of the iron core 12 of the magnetic circuit member 14 of the rotor 15 of the motor main body 10 and inserting and fixing a non-magnetic material having a high density in the gap 12a, the volume of the rotor 15 is reduced. It is possible to easily increase the moment of inertia without any increase and with a slight increase in mass, that is, while the motor body 10 is reduced in size and weight.

  The nonmagnetic material to be fixed in the gap 12a of the iron core 12 may be any nonmagnetic material such as a nonmagnetic metal or resin. Further, there are the following two methods for putting a non-magnetic material into the gap 12a.

  First, as shown in FIG. 7B, the first method is to form a nonmagnetic material 70 formed in a shape that can be inserted into the gap 12a, for example, a rod shape, into the gap 12a as shown in FIG. Insert into and fix by adhesion or press fit.

  In this method, since only the non-magnetic material 70 formed in an insertable shape is inserted, the rotor 15 having an improved moment of inertia can be formed in a very short working time.

  Subsequently, as shown in FIG. 8B, the second method is to fill the gap 12a with the filling device 71 in a state where the non-magnetic material is melted in a viscous state and solidify the nonmagnetic material as shown in FIG. As shown in a), the nonmagnetic material 70 is fixed in the gap 12a.

  This method requires time to solidify the nonmagnetic material 70 melted in a viscous state, but the moment of inertia can be further improved because the gap 12a is filled with the nonmagnetic material 70 without a gap.

  In the above-described example, the nonmagnetic material 70 is fixed to all the gaps 12a of the iron core 12. However, the present invention is not limited to this, and there are a plurality of gaps 12a in the iron core 12. In this case, the gap 12a for fixing the nonmagnetic material 70 can be arbitrarily selected according to the required moment of inertia.

  As described above, the impact rotary tool 1 shown as the embodiment of the present invention can be mounted with a motor having an increased moment of inertia with a very simple configuration while realizing a reduction in size and weight. Accordingly, the impact rotary tool 1 itself is also reduced in size and weight to enhance the user's feeling of use and to give a sufficient impact torque, so that high performance as a tool can be exhibited.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made depending on the design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it is possible to change.

It is a figure for demonstrating the impact rotary tool shown as embodiment of this invention. It is a figure for demonstrating an impact torque generation mechanism. It is a perspective view for demonstrating a motor main body and a cooling fan. It is a longitudinal cross-sectional view for demonstrating a motor main body and a cooling fan. It is the figure which showed the flow of the air by rotation of a cooling fan. It is a figure for demonstrating the space | gap which the iron core of a magnetic circuit member has. It is a figure for demonstrating the 1st method of fixing a nonmagnetic material to a space | gap. It is a figure for demonstrating the 2nd method of fixing a nonmagnetic material to a space | gap.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Impact rotary tool 10 Motor main body 11 Rotating shaft 12 Iron core 12a Air gap 13 Permanent magnet 14 Magnetic circuit member 15 Rotor 16 Iron core 17 Coil frame 18 Coil 19 Stator 30 Cooling fan 70 Nonmagnetic material

Claims (4)

A rotor having a rotating shaft and a magnetic circuit member fixed to the rotating shaft;
A stator having a magnetic circuit;
A cooling fan fixed to the rotating shaft,
The magnetic circuit member of the rotor is fixed to the rotating shaft by an iron core having a gap communicating with the rotating shaft direction,
A motor characterized in that a non-magnetic material having a high density is fixed in the gap. The motor according to claim 1, wherein the non-magnetic body is formed in a shape that can be inserted into the gap, and is inserted into and fixed to the gap. 2. The motor according to claim 1, wherein the nonmagnetic material is filled in the gap in a melted state and solidified in the gap to be fixed. A main drive side rotation member and a driven side rotation member;
In a state where the load torque applied to the driven side rotating member is small, the main driving side rotating member and the driven side rotating member rotate integrally, and when the load torque increases, the main driving side rotating member and the After the driven side turning member is once separated, it is configured to be integrated again by the return means,
When reintegrated by the return means, the driving torque is applied impactively by the inertial force accompanying the rotation of the main driving side rotating member from the main driving side rotating member to the driven side rotating member. For impact rotary tools,
The impact rotary tool which mounts the motor of any one of Claim 1 thru | or 3 which rotates the said main drive side rotation member.

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