JP2001150361A - Power driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power driver capable of adjusting the torque while constantly keeping the clearance between magnets forming a magnetic clutch, improving the durability and reliability with the reduction of the load applied to a bearing, and further improving the assemblability with a simple structure. SOLUTION: In this power driver comprising a reduction gear mechanism 3 and a clutch mechanism 4 for cutting the driving force when the predetermined torque is obtained, the clutch mechanism 4 is composed of a magnetic clutch 5 and a magnetic element 6 for adjusting the torque, inserted into a clearance between both magnets 5a, 5b forming the magnetic clutch 5 in such manner that it can be taken in and out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric screwdriver having a speed reduction mechanism and a torque-adjustable clutch mechanism for cutting off a driving force when a set torque is reached, between a driving motor and an output shaft. It is.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 9-254046, there has been known an electric screwdriver having a clutch which cuts off a driving force when a set torque is reached, in which the clutch is formed by a magnetic clutch. .
Although the detailed description of the electric screwdriver is omitted, FIG.
As shown in the figure, a speed reduction mechanism (not shown, see Japanese Patent Application Laid-Open No. 9-254046) is provided between the driving motor 1 and the output shaft.
And a clutch mechanism 4 (magnet clutch 5) that cuts off the driving force when the set torque is reached.

In the electric screwdriver, a motor 1 as a power source and a gear case 11 are connected by a mount 12, and a transmission in a gear case 11 which is an output shaft of the motor 1 and serves as a driving shaft 13 is provided. The pin serving as the input shaft 1a of the section is press-fitted and fixed to the magnet clutch 5.
A gap having a width L is provided between the two magnets 5a and 5b constituting the magnet clutch 5, and is arranged so as to be in non-contact. The one magnet 5a rotates integrally with the driving shaft 13 of the motor 1, and the other magnet 5b rotates integrally with the rotating shaft 17 as the output shaft 16. In this case, the rotating shaft 17 as the output side shaft 16 is pivotally supported by a bearing 19,
The gear case 11 is connected and held via the bearing 19 and the bearing holder 36.

Further, in the electric driver, a clutch mechanism 4 formed by a magnet clutch 5 can adjust the torque. That is, the adjustment handle 35 is provided on the gear case 11 only for relative rotation freely, and the adjustment handle 35
35 and the bearing holder 36 are screwed together with screws. In this case, by rotating the adjustment handle 35, the bearing holder
36 is moved in the axial direction, and the magnet 5 of the magnet clutch 5 is moved.
The gap width dimension L between a and 5b is changed and adjusted to perform torque adjustment.

[0005]

However, in the above-mentioned prior art, a variable axial force is generated in the bearing 19 when the magnet clutch 5 is operated or not operated. There is a problem that the life of the support portion is likely to be shortened. Further, in order to move one magnet 5b of the magnet clutch 5, a clutch power transmission mechanism (a coupling mechanism slidable by rotation restraint) on the moving side is required, which complicates the assembly and the structure of the mechanism. Therefore, there is a problem that it is difficult to manufacture, and the number of parts increases, which leads to an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made in order to solve all the problems in the prior art described above, and its object is to adjust the torque while keeping the gap between the two magnets constituting the magnet clutch constant. Accordingly, it is an object of the present invention to provide an electric screwdriver whose load on a bearing is reduced, durability and reliability are improved, the structure is simple, and the assemblability is improved.

[0007]

According to a first aspect of the present invention, there is provided an electric screwdriver comprising: a speed reduction mechanism between a driving motor and an output shaft; and a clutch mechanism for cutting off a driving force when a set torque is reached. An electric screwdriver comprising: a clutch mechanism formed by a magnetic clutch; and a magnetic material for torque adjustment that is freely inserted into and removed from a gap between the two magnets constituting the magnetic clutch.

Therefore, in this case, since a magnetic material for torque adjustment is provided which is freely inserted into and removed from the gap between the two magnets of the clutch mechanism formed by the magnet clutch, the magnetic material is inserted into the gap. By changing and adjusting the amount, the torque of the clutch mechanism can be adjusted. That is, when a magnetic material is inserted into the gap between the two magnets constituting the magnet clutch, the facing area of the two magnets decreases according to the inserted amount, and the magnetic path is cut off by that much. As a result, the transmission torque of the clutch mechanism decreases. The torque is adjusted in this way, but at this time, the gap between the two magnets constituting the magnet clutch is always kept constant, the load on the bearing does not increase, and the durability and reliability are improved. The structure is simple, and the assemblability is improved.

According to a second aspect of the present invention, there is provided the electric screwdriver according to the first aspect, wherein the magnetic body is formed in a plate shape thinner than a gap width between the two magnets.

Therefore, in this case, particularly, since the magnetic body is formed in a plate shape thinner than the gap width between the two magnets, the magnetic body is thinned and the gap width between the two magnets is also reduced. Thus, the clutch mechanism formed by the magnetic clutch can be stored compactly. In addition, when the magnetic body has a thin plate shape, a light weight and a large area can be secured, so that the operability and accuracy of torque adjustment are improved.

According to a third aspect of the present invention, there is provided the electric screwdriver according to the first or second aspect, wherein the magnetic members are arranged to face each other so as to be inserted from both sides of the gap. I do.

Therefore, in this case, in particular, since the magnetic members are disposed so as to face each other so as to be inserted from both sides of the gap, it is necessary to insert both the opposite magnetic members equally into the gap from both sides thereof. Thus, the torque can be adjusted in a well-balanced manner about the axis, the rotation is smooth even if the clutch mechanism operates, and the generation of vibration and noise can be prevented.

According to a fourth aspect of the present invention, there is provided the electric screwdriver according to the third aspect, wherein an elastic means for urging the two magnetic members outward is provided between the opposing magnetic members. An operating body that presses the opposing magnetic body from outside against the elastic urging force and inserts the magnetic body into the gap is externally fitted.

Therefore, in this case, in particular, the torque can be easily adjusted by operating the operating body which presses the opposing magnetic bodies and inserts the magnetic body into the gap from the outside. Is returned by being urged outward by the elastic means, so that the adjusting operation is performed smoothly.

The electric screwdriver according to a fifth aspect of the present invention is the electric screwdriver according to the second aspect, wherein the magnetic material has a substantially donut plate shape having an opening having a size substantially matching the outer shape of the magnet in the middle. And the inner peripheral edge portion of the opening of the magnetic body is slidably inserted into the gap.

Therefore, in this case, particularly, the magnetic body is formed in a substantially donut shape having an opening having a size substantially matching the outer shape of the magnet in the middle thereof, and the inner peripheral edge portion of the opening is formed in the gap. The torque adjustment is performed by being slidably inserted. Since the whole magnetic body is integrally slide-shaped in a substantially donut shape, the operation mechanism can be simplified.

According to a sixth aspect of the present invention, there is provided the electric screwdriver according to the fifth aspect, wherein the substantially screw-shaped magnetic member is pivotally supported, and the magnetic member is rotated to form an inner portion of the opening. An operation piece for inserting the peripheral portion into the gap is provided so as to protrude from the magnetic body.

Therefore, in this case, in particular, by rotating the magnetic body with an operating piece protruding from the substantially donut-shaped magnetic body, the inner peripheral edge portion of the opening of the magnetic body is inserted into the gap. In this case, the torque adjustment is performed. At this time, the substantially donut-shaped magnetic body is integrally rotated and operated as a whole, so that the operating mechanism is simplified, and the magnetic body is formed as a single component. And the number of parts can be reduced.

According to a seventh aspect of the present invention, in the electric screwdriver according to the fifth aspect, a substantially donut plate-shaped magnetic material is divided and formed in the form of a diaphragm mechanism of a camera, and an opening in the middle thereof is formed. It is characterized in that it can be scaled.

Therefore, in this case, in particular, the substantially donut-shaped magnetic material is divided and formed in the form of a diaphragm mechanism of a camera, and the opening in the middle thereof is enlarged and reduced. The peripheral part is evenly inserted into the gap from the entire circumference,
The torque is adjusted in a well-balanced manner over the entire circumference, the rotation is smooth even if the clutch mechanism operates, and the generation of vibration and noise can be prevented.

According to an eighth aspect of the present invention, there is provided the electric screwdriver according to the seventh aspect, further comprising an operating annular body for expanding and contracting the opening by interlocking the divided magnetic plate pieces of the magnetic material. It is characterized by being fitted outside.

Therefore, in this case, in particular, the torque adjustment can be easily performed in a well-balanced manner by operating the operating annular member for expanding and contracting the opening by interlocking the divided magnetic plate pieces of the magnetic material from the outside. be able to.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS.
4 shows an embodiment corresponding to FIG. 4, wherein the electric driver includes a reduction mechanism 3 between a driving motor 1 and an output shaft 2, a clutch mechanism 4 that cuts off a driving force when a set torque is reached, A magnetic mechanism 6 for torque adjustment, wherein the clutch mechanism 4 is formed by a magnet clutch 5 and is inserted into and removed from the gap between the two magnets 5a and 5b constituting the magnet clutch 5. Is provided.

In the electric screwdriver of this embodiment, the magnetic body 6 is formed in a plate shape thinner than the width L of the gap between the magnets 5a and 5b, and is inserted from both sides of the gap. The magnetic bodies 6 are arranged to face each other. In this case, an elastic means 7 for urging the two to the outside is provided between the opposing magnetic bodies 6, and the opposing magnetic bodies 6 are pressed from the outside against the elastic urging force of the elastic means 7. The operation body 8 for performing the insertion operation in the gap may be fitted outside.

Hereinafter, the operation principle of the electric screwdriver according to the embodiment will be described in detail with reference to FIGS. A motor 1 as a power source and a gear case 11 are connected by a mount 12, and a pin serving as an input shaft 1 a of a transmission unit in the gear case 11, which is an output shaft of the motor 1 and serves as a driving side shaft 13, ,
The magnet clutch 5 is press-fitted and fixed. In this case, the magnet clutch 5 is called a magnet coupling clutch, and includes a magnet mounting plate 5c fitted and fixed to the input shaft 1a, a driving side clutch plate 14 and an output side clutch as shown in FIG. Magnets 5a and 5b magnetized so as to have different polarities alternately in the plane direction of the disk constituting 15
And a magnet mounting plate 5d.

The magnet mounting plate 5c and the magnet 5a, and the magnet 5b and the magnet mounting plate 5d are bonded to each other in a non-separable manner. A gap having a width L is provided between the two magnets 5a and 5b constituting the magnet clutch 5, and they are arranged so as to be in non-contact with each other. Magnet mounting plate 5d and rotating shaft 17 as output shaft 16
And the sun gear 18 are press-fitted and fixed so as to rotate integrally, and are held by bearings 19.

A speed reduction mechanism 3 is provided between the rotation shaft 17 and the output shaft 2. The speed reduction mechanism 3 includes a sun gear 18, a planet gear 20, a ring gear 21, a pin 22, a carrier 23,
Sun gear 24, planet gear 25, ring gear 26, pin 2
7. A two-stage well-known planetary gear mechanism comprising a carrier 28. Therefore, the rotation from the rotating shaft 17 is greatly reduced and taken out to the output shaft 2. A known chuck (not shown) is attached to the output shaft 2, and a known screw fastener (not shown) is attached to the chuck to form an electric screwdriver.

When a low-load torque is applied to the output shaft 2 during work such as screw tightening, the torque transmitted from the motor 1 is transmitted to the magnet 5a via the magnet mounting plate 5c, and the two magnets 5a and 5b are rotated.
The rotational force is transmitted to the magnet mounting plate 5d by the attraction force between the a and 5b, and the rotational force reduced by the reduction mechanism 3 including the planetary gear mechanism is transmitted to the output shaft 2. During such screw tightening work, for example, if the head of the screw is seated on the tightening surface and a high load torque is applied to the output shaft 2, a high torque is generated by the attraction force of both magnets 5a and 5b. The transmission cannot be performed, and only the magnet mounting plate 5c and the magnet 5a on the input side start to idle and a large load is prevented from being applied to the motor 1. In FIG. 1, 29 is a bearing, and 30 is a watertight material.

In the electric screwdriver of the embodiment, the magnets 5a, 5b
The magnetic body 6 is freely inserted into and removed from the gap therebetween, whereby the torque of the clutch mechanism 4 is adjusted. The magnetic body 6 is made of a magnetic steel plate, and is formed to be thinner than the gap width L between the magnets 5a and 5b constituting the magnet clutch 5. As shown in FIGS. 3 and 4, the magnetic members 6 are disposed opposite each other in pairs, and elastic means 7 composed of a compression spring is disposed between the two magnetic members 6 at symmetrical positions on both sides of the axis. ing. An operating body 8 that presses the magnetic body 6 from the outside is externally fitted. In this case, the two magnetic bodies 6 urged outward by the elastic means 7 are a ring-shaped operating body 8 and an outer casing 31. And are positioned and held.

When the operation plate 8 is rotated, the state shown in FIG. 3 changes to the state shown in FIG. In this case, the two magnetic bodies 6 move toward the axis against the elastic biasing force of the elastic means 7, and the distance H between them becomes short, and the two magnetic bodies 6 become the two magnets constituting the magnet clutch 5. The magnets 5a and 5b are inserted into the gap between the magnets 5a and 5b, so that the mutually facing areas of the magnets 5a and 5b are reduced. When the magnetic body 6 is inserted into the gap between the two magnets 5a and 5b,
The magnetic path is cut off and the transmission torque is reduced, so that the torque of the clutch mechanism 4 is adjusted.

Therefore, in the electric screwdriver of this embodiment, the magnetic body 6 for torque adjustment is provided which is freely inserted into and removed from the gap between the magnets 5a and 5b of the clutch mechanism 4 formed by the magnet clutch 5. Because
The torque of the clutch mechanism 4 can be easily adjusted by changing and adjusting the insertion amount of the magnetic body 6 into the gap.

That is, when the magnetic body 6 is inserted into the gap between the magnets 5a and 5b constituting the magnet clutch 5, the facing area of the magnets 5a and 5b decreases according to the inserted amount. Then, the magnetic path is interrupted by that much, and the transmission torque of the clutch mechanism 4 decreases. The torque adjustment is performed in this manner. At this time, the gap dimension L between the two magnets 5a and 5b constituting the magnet clutch 5 is adjusted.
Is always constant, the load applied to the bearing 19 does not increase unlike the related art, the durability and reliability are improved, the structure is simple, and the assembling property is improved.

In the electric screwdriver of this embodiment, the magnetic body 6 is formed in a plate shape smaller than the gap width L between the magnets 5a and 5b. By reducing the gap width between the two magnets, the clutch mechanism 4 formed by the magnet clutch 5 is compactly accommodated. Moreover, since the magnetic body 6 is in the form of a thin plate, it is possible to secure a light weight and a large adjustment area, and the operability and accuracy of torque adjustment are improved.

Further, in the electric screwdriver of the present embodiment, since the magnetic members 6 are arranged to face each other so as to be inserted from both sides of the gap, the two magnetic members 6 facing each other are placed on both sides of the gap. , The torque can be adjusted in a well-balanced manner about the axis, and the rotation is smooth even if the clutch mechanism 4 is actuated, thereby preventing the generation of vibration and noise. Moreover, in this case, the torque can be easily adjusted by operating the operating body 8 that presses the opposing magnetic bodies 6 and inserts them into the gap from outside.
At this time, the two magnetic bodies 6 are urged outward by the elastic means 7 to return, so that the adjustment operation can be performed smoothly.

FIG. 5 shows another embodiment corresponding to the first, second, fifth and sixth aspects of the present invention. In the electric screwdriver of this embodiment, the size of the electric screwdriver substantially matches the outer shape of the magnet in the middle. The magnetic body 6 is formed in a substantially donut plate shape having an opening 9 having an opening 9, and the inner peripheral portion of the opening 9 of the magnetic body 6 is slidable into the gap between the magnets 5 a and 5 b constituting the magnet clutch 5. It is made to be inserted in. In addition, an operating piece for pivotally supporting the substantially donut-shaped plate-shaped magnetic body 6 and rotating the magnetic body 6 to insert the inner peripheral edge portion of the opening 9 into the gap.
62 protrudes from the magnetic body 6. In this case, the magnetic body is pivotally supported by the outer casing 31 at the shaft portion P, and
An operation piece 62 protrudes outside from a slit 32 formed in 31.

Therefore, in the electric screwdriver of this embodiment, the magnetic body 6 is formed in a substantially donut plate shape having an opening 9 having a size substantially matching the outer shape of the magnet 5a (5b) in the middle thereof. The torque adjustment is performed by slidably inserting the inner peripheral edge portion of the opening 9 into the gap, and the magnetic body 6 is generally in the form of a donut plate, and is integrally slid. The operation mechanism can be simplified. Moreover, the substantially donut-shaped magnetic body 6
When the magnetic member 6 is rotated by the operation piece 62 protruding from the magnetic member 6, the inner peripheral edge portion of the opening 9 of the magnetic member 6 is inserted into the gap to perform torque adjustment. Since the substantially donut-shaped magnetic body 6 is integrally rotated, the operation mechanism is simplified, and the magnetic body 6 becomes a single part, thereby reducing the number of parts. . Except for the above, the configuration is the same as that of the above-described embodiment shown in FIGS. 1 to 4, and the operation and effect other than those according to claims 3 and 4 are exerted as in the above-described embodiment.

FIGS. 6 and 7 show the first, second, fifth, and fifth aspects of the present invention.
Another embodiment corresponding to FIGS. 7 and 8 is shown. In the electric screwdriver of this embodiment, a substantially donut plate-shaped magnetic body 6 is divided and formed in the form of a diaphragm mechanism of a camera, and an opening 9 in the middle thereof is formed. Is to be scaled. In addition, the operating annular body 10 for expanding and contracting the opening 9 by interlocking the divided magnetic plate pieces 61 of the magnetic body 6 is fitted around the outside.

In this case, the plurality of magnetic plate pieces 61 are pivotally attached to the casing 33 in a cloud shape, and are connected to the ring-shaped operating annular body 10 by joint pieces 34, respectively. The operating annular body 10 and the joint piece 34 are pivotally connected to each other, and the pivot point A between the casing 33 and the magnetic plate piece 61, the magnetic plate piece 61 and the joint piece
A crank mechanism is constituted by a pivot point B with the pivot 34 and a pivot point C with the operating ring 10 and the joint piece 34. For this reason, by rotating the operating annular body 10, the tip of each magnetic plate piece 61 serving as a crank mechanism is rotated toward the axis, and the tip of each magnetic plate piece 61 is rotated by the magnetic clutch 5.
Are inserted into the gap between the two magnets 5a and 5b.

Therefore, in the electric screwdriver of this embodiment, the substantially donut-shaped magnetic body 6 is divided and formed in the form of a diaphragm mechanism of a camera, and the opening 9 in the middle thereof is enlarged and reduced. Therefore, the inner peripheral edge portion of the opening 9 (the end portion of each magnetic plate piece 61) is evenly inserted into the gap from the entire circumference, the torque is adjusted in a well-balanced manner over the entire circumference, and even if the clutch mechanism 4 operates. The rotation is smooth and the generation of vibration and noise is prevented. In addition, the torque adjustment can be easily performed in a well-balanced manner by rotating the operating annular body 10 for expanding and contracting the opening 9 by linking the divided magnetic plate pieces 61 of the magnetic body 6 from outside. it can. Except for the above, the configuration is the same as that of the above-described embodiment shown in FIG. 5, and the operation and effect other than those according to claim 6 are exerted as in the above-described embodiment.

[0040]

As described above, in the electric screwdriver according to the first aspect of the present invention, the torque of the clutch mechanism can be adjusted by inserting the magnetic body into the gap between the two magnets constituting the magnet clutch. At that time, since the gap size between the two magnets remains constant, the load on the bearing does not increase, the durability and reliability are improved, the structure is simple and the assembly is improved. You.

Further, in the electric screwdriver according to the second aspect of the present invention, the clutch mechanism formed by the magnet clutch can be housed in a compact manner. The area can be secured, and the operability and accuracy of torque adjustment are improved.

In the electric screwdriver according to the third aspect of the present invention, in particular, the torque can be adjusted in a well-balanced manner about the axis by inserting the opposing magnetic bodies into the gap evenly from both sides thereof. And the occurrence of vibration and noise can be prevented.

In the electric screwdriver according to the fourth aspect of the present invention, the torque can be easily and smoothly adjusted by operating, from the outside, an operating body which presses the opposing magnetic body and inserts it into the gap. It can be carried out.

In the electric screwdriver according to the fifth aspect of the present invention, in particular, the inner peripheral edge portion of the opening of the magnetic material formed substantially in the shape of a donut plate is slidably inserted into the gap to adjust the torque. The operation mechanism of the slide can be simplified.

In the electric screwdriver according to a sixth aspect of the present invention, in particular, the whole of the magnetic body is integrally rotated by an operation piece projecting from the substantially doughnut-shaped magnetic body. The operation mechanism is simplified, the magnetic body can be made into a single part, and the number of parts can be reduced.

Further, in the electric screwdriver according to the present invention, the opening of the substantially donut-shaped magnetic material is enlarged and reduced like a diaphragm of a camera, and the inner peripheral edge portion of the opening is evenly distributed. It is inserted into the gap from the entire circumference, the torque is adjusted in a well-balanced manner over the entire circumference, and generation of vibration and noise can be prevented.

In the electric screwdriver according to the present invention, in particular, the operating annular body for expanding and contracting the opening by operating the divided magnetic plate pieces of the magnetic material is operated from the outside. Thus, torque adjustment can be easily performed in a well-balanced manner.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electric screwdriver according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a magnet clutch in the electric screwdriver.

FIG. 3 is a sectional view showing a main part of the electric screwdriver.

FIG. 4 is a cross-sectional view showing a main part of the electric screwdriver in a different state.

FIG. 5 is a sectional view showing a main part of an electric screwdriver according to another embodiment.

FIG. 6 is a sectional view showing a main part of an electric screwdriver according to still another embodiment.

FIG. 7 is a cross-sectional view of a main part of the electric screwdriver in a different state.

FIG. 8 is a cross-sectional view showing a main part of a conventional electric screwdriver.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Output shaft 3 Reduction mechanism 4 Clutch mechanism 5 Magnet clutch 5a Magnet 5b Magnet 6 Magnetic body 7 Elastic means 8 Operating body 9 Opening 10 Operating annular body 61 Magnetic plate piece 62 Operating piece

Claims (8)

[Claims] 1. An electric driver comprising a reduction mechanism and a clutch mechanism for cutting off a driving force when a set torque is reached between a driving motor and an output shaft, wherein the clutch mechanism is formed by a magnetic clutch. And an electric screwdriver provided with a torque adjusting magnetic body which is inserted into and removed from the gap between the two magnets constituting the magnet clutch. 2. The electric screwdriver according to claim 1, wherein the magnetic body is formed in a plate shape smaller than a gap width between the two magnets. 3. The electric screwdriver according to claim 1, wherein the magnetic members are arranged so as to face each other so as to be inserted from both sides of the gap. 4. An elastic means for urging the two to the outside is provided between the opposing magnetic bodies, and the opposing magnetic bodies are pressed from the outside against the elastic urging force of the elastic means to form a gap. The electric screwdriver according to claim 3, wherein an operation body for performing an insertion operation is fitted outside. 5. A magnetic material is formed in a substantially donut plate shape having an opening having a size substantially matching the outer shape of the magnet in the middle, and an inner peripheral edge portion of the opening of the magnetic material is slidable into a gap. 3. The electric screwdriver according to claim 2, wherein the electric screwdriver is inserted into the electric screwdriver. 6. An operation piece for pivotally supporting a substantially donut-shaped magnetic body, rotating the magnetic body, and inserting an inner peripheral edge portion of an opening into a gap, and protruding from the magnetic body. The electric screwdriver according to claim 5, wherein 7. The electric screwdriver according to claim 5, wherein a substantially doughnut-shaped magnetic material is formed in the form of a diaphragm mechanism of a camera so as to expand and contract an opening in the middle thereof. 8. The electric screwdriver according to claim 7, wherein an operating annular body for expanding and contracting the opening by interlocking each of the divided magnetic plate pieces of the magnetic body is fitted.