JP4331283B2 - Torque fixed screwdriver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a driver using a torque limiter that can set a tightening torque or a loosening torque of a screw tool with high accuracy, and particularly for assembling small precision parts and joining and assembling weak parts such as plastic products. The present invention relates to a torque-fixed type screwdriver that can be easily and safely tightened or removed with a low torque and is suitable for use.
[0002]
[Prior art]
2. Description of the Related Art Various types of small torque limiters that can be used for transmitting or blocking torque of small power via a rotating shaft have been proposed for information devices and the like.
[0003]
As this type of torque limiter, for example, one configured as shown in FIG. 8 is known. That is, in FIG. 8, reference numeral 10 indicates a cylindrical outer case, and a coil spring 13 is accommodated in the inside 12 of the outer case 10, and a hook 14 provided at one end of the coil spring 13 is attached to the outer case 10. The hook 17 provided at the other end of the coil spring 13 is engaged with the recess 19 of the lid 18 fitted and fixed in the opening end of the outer case 10. The rotary shaft 20 is inserted into the coil spring 13 and the rotary shaft 20 is rotatably supported by the bearing portion 21 of the outer case 10 and the lid body 18.
[0004]
The coil spring 13 has a small-diameter portion 13a and a large-diameter portion 13b, and the inner diameter of the small-diameter portion 13a is equal to or slightly larger than the outer diameter of the rotating shaft 20 in a natural state. Then, in this dimension state, the coil spring 13 is assembled in the outer case 10 and the rotary shaft 20 is inserted into the small diameter portion 13a, and then the lid body 18 is fitted to engage the hooks 14 and 17 and the recesses 16 and 19, respectively. In this state, the lid 18 is rotated and the coil spring 13 is twisted in the winding direction, thereby reducing the diameter of the small-diameter portion 13a so that the rotary shaft 20 is tightly fitted. It is configured to give tight binding power.
[0005]
Therefore, when the torque limiter configured in this way rotates the rotating shaft 20 in the direction opposite to the winding direction of the coil spring 13, the rotational force is transmitted to the outer case 10 via the coil spring 13, and the torque limiter rotates at this time. The minimum value of torque that causes slippage between the shaft 20 and the small diameter portion 13a is the torque value. The torque value can be adjusted by rotating the lid 18 and changing the amount of twist of the coil spring 13.
[0006]
Conventionally, tightened objects such as bolts, nuts, and screws are tightened with a predetermined tightening torque by an electric screwdriver or a manual screwdriver, and how much torque is loosened once a screw is tightened. A torque driver is generally known as a means for measuring the torque and always tightening with a uniform torque. This torque driver uses a spiral spring and displays the amount of mechanical deformation as a torque value on a scale plate, or applies torsion of a torsion bar.
[0007]
Therefore, in the case of a conventional electric screwdriver or manual screwdriver, when a strong counter load is applied to the driver bit when tightening a screw or the like, this is set to a predetermined torque value by a clutch mechanism that operates with a preset tightening torque. It has been proposed to detect the reached state and operate the clutch mechanism to temporarily disconnect the coupling between the output shaft of the electric motor or the manual drive shaft and the driven shaft (driver bit). It has been implemented.
[0008]
On the other hand, apart from the above-mentioned clutch mechanism such as an electric screwdriver or manual screwdriver, a driver bit is used as a means for directly detecting with a screwdriver how much torque has been tightened against the mounting object. Torque detectors are also known that are configured to detect a strong counteracting load acting, for example, by means of a strain gauge mounted on one side of the torsion bar.
[0009]
Therefore, according to the torque detector, during the screwing operation, the stress distortion continuously transmitted to the torsion bar can be directly read and monitored, so that the fluctuation of the torque value from the start of the tightening of the screw to the completion of the tightening Can be measured to find the optimum tightening torque.
[0010]
[Problems to be solved by the invention]
However, in a conventional torque driver, torque meter, torque detector, or the like having the above-described configuration, a torque value at the time of tightening a general screw tool, or a continuous fluctuation from the start to the completion of screw tool tightening. It is possible to properly measure or monitor the torque value to be used when the strain gauge is used, but it is particularly vulnerable to the assembly of small precision parts and plastic products when tightening a large amount of screws. As in the case of connecting and assembling various parts, it is difficult to safely and accurately perform the screw tightening and removal operation so that the torque value is constant and all torque is low.
[0011]
Conventionally, as described above, an electric driver or a manual driver having a clutch mechanism is known, but this clutch mechanism has a mechanical configuration and is coupled to a drive shaft during clutch operation. In particular, when assembling various electronic parts such as hard disks and precision machine parts, etc., the parts may be damaged. There is a drawback that has an adverse effect, and thus, there is an increasing demand for drivers that enable shockless torque setting.
[0012]
The present inventors have conducted intensive studies and results of repeated trial, instead of the conventional mechanical clutch mechanism, as a means to shut off the power to perform the tightening operation of the screw member, the coil spring is known in the prior By adopting the configuration of a friction type torque limiter (see FIG. 8) using frictional contact resistance and incorporating this torque limiter in the gripping part casing of the driver, a torque fixed type driver capable of satisfying the above requirements is obtained. I was able to find out.
[0013]
That is, in this case, the drive shaft is rotatably housed inside the outer case, the coil spring is tightly fitted on the outer periphery of the drive shaft, and the hooks provided at both ends of the coil spring are respectively attached to the case or this. A torque limiter that is engaged with a member fixed to the outer casing, and the outer case is enclosed and fixed by the gripping casing of the driver or the gripping casing of the driver, and is attached to the tip of the drive shaft of the torque limiter. By adopting a configuration in which a driver bit is provided, a torque fixed type driver can be easily created.
[0014]
Further, instead of the friction type torque limiter using the coil spring, it is also possible to employ a magnetic type torque limiter using a permanent magnet. In this case, the torque limiter is configured as a non-contact type. It has been found that a torque-fixed type driver capable of setting a more shockless torque can be obtained.
[0015]
Therefore, the torque fixed type driver constructed in this way has a constant torque value with a low torque, particularly when assembling small precision parts or connecting and assembling fragile parts such as plastic products. As described above, operations such as the tightening or removing operation of the small screw or the confirmation tightening of the pre-tightened screw tool can be achieved safely and with high accuracy.
[0016]
Accordingly, an object of the present invention is to achieve a smooth and high-precision tightening of a screw tool at a constant torque value at all times, and to make a simple and compact configuration, and to have an adverse effect due to a shock or the like on a mounting object of the screw tool. the can be reliably prevented, yet to provide a torque fixed type driver applying a torque limiter which can be manufactured at a low cost.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, a torque fixed type driver according to claim 1 of the present invention has a cylindrical permanent magnet fixedly disposed on the inner peripheral surface of an outer case, and a drive shaft is rotated at the center of the permanent magnet. A cylindrical magnetic member is supported and fixed at the outer peripheral portion of the drive shaft so as to face the inner peripheral surface of the permanent magnet in a non-contact manner, and the rear end portion of the outer case is covered with a lid. Equipped with a torque limiter that is closed and fixed with
The drive shaft of the torque limiter is surrounded and held by a sleeve, and this sleeve is supported by the outer case via a one-way clutch, and a driver bit is detachably attached to the tip of the sleeve ,
The torque limiter is rotatably held by a grip casing, and the output shaft of the electric motor is coaxial with the drive shaft at the rear end of the torque limiter with respect to a lid for closing and fixing the outer case. Detachably coupled ,
The outer periphery of the electric motor is surrounded by an outer casing, and the outer casing is detachably coupled to the gripping casing that holds the torque limiter .
Further, the rear end portion of the electric motor is fixed in the outer casing via a flat plate extending coaxially therewith, and a torque gauge is measured by attaching a strain gauge to one side of the plate. It is an electric motor drive type torque fixed type driver configured to be obtained .
[0022]
According to a second aspect of the present invention, there is provided an electric motor drive type torque fixed type driver, wherein a reduction gear is coupled to the output shaft of the electric motor, and the output shaft of the reduction gear is closed with an outer case of the torque limiter. The lid is detachably coupled so as to be coaxial with the drive shaft.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a torque fixed type driver to which the torque limiter according to the present invention is applied will be described in detail with reference to the accompanying drawings.
[0024]
Configuration example 1
FIG. 1 shows a configuration example of a torque fixed driver . That is, in FIG. 1, reference numeral 30 indicates a cylindrical gripping part casing in which a torque limiter is accommodated. However, in this configuration example , the grip casing 30 is configured as an outer case of a torque limiter, and an opening 30a is provided at one end of the outer case 30 and a lid 32 is detachably attached to the other end. Consisting of A coil spring 36 is housed in the inside 34 of the outer case 30, and a hook 38 a provided at one end of the coil spring 36 is engaged with a fitting recess 32 a formed in the lid 32, and A hook 38 b provided on the other end of the coil spring 36 is engaged with a fitting recess 32 b formed on an end wall portion on the opening 30 a side of the outer case 30. Further, the rotary shaft 40 is inserted and arranged inside the coil spring 36, and the rotary shaft 40 is attached to the outer case 30. The bearing portion 42 of the lid body 32 is rotatably supported.
[0025]
The coil spring 36 has a small-diameter portion 36a and a large-diameter portion 36b, and the inner diameter of the small-diameter portion 36a is equal to or slightly larger than the outer diameter of the rotating shaft 40 in a natural state. In this state, the coil spring 36 is assembled into the outer case 30 and the rotary shaft 40 is inserted into the small-diameter portion 36a. Then, the lid 32 is attached to the outer case 30, and the hooks 38a and 38b are fitted to the fitting recesses, respectively. 32a and 32b are engaged, and the lid 32 is rotated in this state and the coil spring 36 is twisted in the winding direction to reduce the diameter of the small-diameter portion 36a so that the rotary shaft 40 is tightly fitted. It is comprised so that a tight binding force may be given to radial direction.
[0026]
Therefore, in the torque limiter configured as described above, when the outer case 30 is rotated in the same direction as the winding direction of the coil spring 36, the rotational force is transmitted to the rotating shaft 40 via the coil spring 36, and at this time, the rotating shaft The minimum value of the torque that causes slippage between 40 and the small diameter portion 36a of the coil spring 36 can be set as the constant torque value. In setting the constant torque value, the lid body 32 is rotated to change the torsion amount of the coil spring 36, so that it can be adjusted and set as appropriate.
[0027]
In this configuration example , the fixed torque driver can be realized by directly connecting a driver bit 44 as a drive shaft to the rotary shaft 40 of the torque limiter having the above configuration. That is, when screw tightening is performed using the torque fixed type screwdriver having the above-described configuration, if the tightening torque reaches a preset constant torque value, the sliding between the rotary shaft 40 and the small diameter portion 36a of the coil spring 36 will occur. As a result, the gripping part casing 30 idles with respect to the rotary shaft 40, whereby a constant torque tightening can be achieved.
[0028]
In the configuration example shown in FIG. 1, a drive shaft 46 is coupled to the rotary shaft 40 of the torque limiter, and a sleeve 48 is fixed to the drive shaft 46 so that a ball is attached to the tip of the sleeve 48. A chuck mechanism 50 including 49a, a collar 49b, and a spring 49c is provided, and the driver bit 44 is detachably coupled via the chuck mechanism 50. Also with this configuration, it is possible to achieve the constant torque tightening of the screw with the driver bit 44 exactly as described above.
[0029]
Further, in this configuration example , as shown in FIG. 1, a part of the sleeve 48 is formed to project outward in the radial direction, and the drive shaft 46, that is, the driver bit 44 can be rotated by an external operation. 47 is provided. That is, the manual adjustment unit 47 can be used effectively when performing additional tightening after the constant torque tightening of the screw.
[0030]
Configuration example 2
FIG. 2 shows another configuration example of the torque fixed type driver . That is, in FIG. 2, for convenience of explanation, the same reference numerals are given to the same components as those in the configuration example 1 shown in FIG. 1, and detailed description thereof is omitted. In this configuration example , the drive shaft 46 is coupled to the rotary shaft 40 of the torque limiter, the sleeve 48 is surrounded and fixed to the drive shaft 46, and the chuck mechanism 50 is provided at the tip of the sleeve 48. In the same configuration as the configuration example 1 , the gripping portion casing 30 is extended so as to surround the outer periphery of the coupling portion of the sleeve 48 with the drive shaft 46, and the outer periphery of the sleeve 48 is interposed via the one-way clutch 52. The gripping portion casing 30 holds the structure.
[0031]
In this case, as the one-way clutch 52, for example, as shown in FIG. 3, a ring member 54 in which a plurality of rollers 53 with a small frictional contact resistance are fitted and arranged on the inner peripheral surface at a predetermined interval in the circumferential direction. Thus, a wedge piece 56 may be inserted into the fitting groove 55 of the roller 53 so as to allow the roller 53 to roll only in one direction. Therefore, in this case, by inserting and fixing to the sleeve 48 so as to be in pressure contact with the surface of the roller 53, the gripping portion casing 30 can rotate (screw) to the side where the wedge piece 56 is inserted. Rotation in the direction of removal) is locked, and the manual turning force is directly transmitted to the driver bit 44, so that the screw removal operation can be easily achieved. In the rotation operation in the opposite direction, the rotation of the sleeve 48 is free via the torque limiter, and a smooth constant torque tightening operation can be achieved.
[0032]
Therefore, according to the torque fixed type driver of the present configuration example , torque is transmitted directly from the gripping casing 30 to the driver bit 44 via the sleeve 48 without affecting the torque limiter particularly when removing the screw. Appropriate and smooth work can be achieved.
[0033]
In this configuration example , as in the configuration example 1 , a manual adjustment unit for performing additional tightening after the constant torque tightening of the screw can be appropriately provided.
[0034]
Configuration example 3
FIG. 4 shows still another configuration example of the torque fixed type driver. That is, in the present configuration example , as shown in FIG. 4, a plurality of torque limiters 60A and 60B are arranged in tandem in the axial direction, and the drive shaft 46A of one torque limiter 60A is connected to the outer case of the other torque limiter 60B. The plurality of torque limiters 60 </ b> A and 60 </ b> B are combined and connected to 30 </ b> B, and are configured to be accommodated in the gripping part casing 62. Of course, the drive shaft 46B protruding from the other torque limiter 60B can adopt a coupling configuration with the driver bit 44 as in the first or second configuration example (see FIGS. 1 and 2). 2).
[0035]
When a plurality of torque limiters 60A and 60B are used, a configuration in which the torque limiters having the above-described configuration are arranged in tandem on the same drive shaft may be employed.
[0036]
Configuration example 4
FIG. 5 shows another configuration example of the torque fixed type driver . That is, in this configuration example , as shown in FIG. 5, for example, a torque limiter drive shaft 46 and a rear end portion closed by a lid 32 of the outer case 30 of the torque fixed driver having the configuration shown in FIG. A shaft coupling recess 64 is provided so as to be coaxial, and an output shaft 68 of the electric motor 66 is detachably coupled to the shaft coupling recess 64 so that the torque fixed driver can be driven to rotate by the electric motor 66. Is.
[0037]
In this case, a first outer casing 70 that surrounds and supports the electric motor 66, and a second outer casing 72 that surrounds the torque-fixed driver and is rotatably supported via a bearing 71 at the position of the sleeve 48. Is a detachable coupling configuration by the screw portion 73. As a result, a plurality of types of torque-fixed type drivers for which a predetermined torque setting has been performed in advance can be connected to the electric motor 66 so as to be detachable and replaceable.
[0038]
In the configuration example shown in FIG. 5, to couple the appropriate reduction gear 67 to the electric motor 66, the output shaft 68 of the speed reducer 67, definitive to the rear end of the outer casing 30 of the torque fixed type driver It consists of the structure couple | bonded with the axial coupling recessed part 64 provided in the cover body 32. FIG. In FIG. 5, reference numeral 74 indicates a power connection cord derived from the electric motor 66.
[0039]
Configuration example 5
FIG. 6 shows still another configuration example of the torque fixed driver . That is, the present embodiment shows a modification of the configuration example 4 shown in FIG. 5, and as shown in FIG. 6, for the electric motor 66 surrounded and supported by the first outer casing 70, the electric motor The first outer casing 70 is rotatably surrounded with respect to the outer peripheral portion of 66, and the rear end portion of the electric motor 66 extends through a flat plate (torsion bar) 76 extending coaxially therewith. The first outer casing 70 is fixed, and a strain gauge 78 is attached to one side surface of the plate 76 so that the torque value can be measured.
[0040]
According to the torque fixed type driver of this configuration example configured as described above, the accuracy of the torque limiter applying the frictional resistance of the coil spring and the slip function is relatively accurate, but the function is not used for a long period of use. If it is necessary to monitor the torque continuously, or join the ISO (International Organization for Standardization) or confirm safety standards based on the PL Law (Product Liability Law), When it is necessary to keep a continuous record of torque, the torque fixed type driver of this configuration example is extremely effective.
[0041]
Example 1
Figure 7 shows an exemplary embodiment of a torque fixed type driver according to the present invention. That is, in this embodiment, as shown in FIG. 7, a magnetic non-contact type torque limiter 80 is applied instead of the friction type contact type torque limiter described above.
[0042]
However, in the non-contact type torque limiter 80, a cylindrical permanent magnet 83 is fixedly disposed on the inner peripheral surface of the outer case 82, and a drive shaft 84 is rotatably inserted in the center of the cylindrical permanent magnet 83. At the outer peripheral portion of the drive shaft 84, a cylindrical magnetic member 85 is fixed to the drive shaft 84 through a support member 86 as appropriate, facing the inner peripheral surface of the permanent magnet 83 and not in contact therewith. Consists of arranged configurations.
[0043]
The torque limiter 80 configured as described above surrounds and supports the outer peripheral portion of the outer case 82 with a gripping portion casing 88, and the drive shaft 84 of the torque limiter 80 protrudes to the outside at one end of the gripping portion casing 88. The opening 88a is provided, and the lid 89 is detachably attached to the other end.
[0044]
In the present embodiment, with respect to the drive shaft 84 which projects from the opening 88a of the grip portion casing 88, similarly to the configuration example 1 shown in FIG. 1, the sleeve 48 surrounds fixed, the distal end of the sleeve 48 A chuck mechanism 50 composed of a ball, a collar, and a spring is provided, and the driver bit 44 is detachably coupled via the chuck mechanism 50. Further, the outer peripheral portion of the sleeve 48 is configured to be held by the gripping portion casing 88 via the one-way clutch 52, similarly to the configuration example 2 shown in FIG.
[0045]
Therefore, the torque fixed type driver of the present embodiment configured as described above can achieve the constant torque tightening as in the configuration example 1 and the configuration example 2 described above. In particular, according to the torque fixed type driver of the present embodiment, the torque value can be easily set by adjusting the magnetic characteristics of the permanent magnet 83 constituting the torque limiter 80, and the torque can be easily set for a long time. Even when used, there is almost no torque fluctuation, and since it is a non-contact type configuration, it is possible to obtain an excellent advantage such that an adverse effect due to a shock or the like can be almost completely prevented.
[0046]
Also, in the torque fixed type driver according to the present embodiment, the same operation as each configuration example is achieved by adding the same configuration as the configuration example 3 to the configuration example 5 shown in FIGS. 4 to 6 described above. An effect can be obtained.
[0047]
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the spirit of the present invention.
[0048]
【The invention's effect】
As is clear from the above-described embodiments, the torque fixed type driver according to the present invention has a cylindrical permanent magnet fixedly disposed on the inner peripheral surface of the outer case, and a drive shaft can be rotated at the center of the permanent magnet. A torque limiter that is inserted and disposed, and that supports and fixes a cylindrical magnetic member that faces the inner peripheral surface of the permanent magnet and is not in contact with the inner peripheral surface of the permanent magnet at the outer peripheral portion of the drive shaft; Or by fixing the outer case with a gripper casing and closing and fixing the rear end of the outer case with a lid, and providing a screwdriver bit at the tip of the drive shaft . Tightening can be achieved smoothly and accurately with a constant torque value at all times, and a simple and compact structure can be used to prevent adverse effects such as shocks on the tightening object of the screw tool. It can indeed prevent, moreover can be manufactured at a low cost.
[0049]
In particular, according to the torque fixed type driver according to the present invention, it is possible to obtain a constant torque value at a low torque, as in the case of assembling small precision parts or coupling and assembling of fragile parts such as plastic products. In addition, operations such as a small screw tightening or removal operation or a confirmation tightening of a pre-tightened screw tool can be achieved safely and with high accuracy. Furthermore, since a fixed torque, since there is no danger of the operator or the like will change the torque value, obtained like a convenient and and safe on product quality control, many outstanding advantages It is done.
[Brief description of the drawings]
FIG. 1 is a cross-sectional side view of an essential part showing a configuration example of a torque fixed driver .
FIG. 2 is a cross-sectional side view of an essential part showing another configuration example of a torque fixed driver .
3 is a cross-sectional view of the torque fixed type driver shown in FIG. 2 taken along line III-III.
FIG. 4 is a schematic cross-sectional explanatory view of a main part showing still another configuration example of the torque fixed driver .
FIG. 5 is a schematic cross-sectional explanatory view of a main part showing another configuration example of the torque fixed driver .
FIG. 6 is a schematic cross-sectional explanatory view of a main part showing still another configuration example of the torque fixed driver .
FIG. 7 is a schematic cross-sectional explanatory view of an essential part showing a typical embodiment of a torque fixed driver according to the present invention.
FIG. 8 is a schematic sectional side view showing a configuration of a conventional torque limiter.
[Explanation of symbols]
30 Grip part casing (outer case)
30a opening 30b fitting recess 30A, 30B outer case 32 lid 32a fitting recess 34 inner 36 coil spring 36a small diameter portion 36b large diameter portion 38a, 38b hook 40 rotating shaft 42 bearing portion 44 driver bit 46 drive shaft 46A, 46B Drive shaft 47 Manual adjustment portion 48 Sleeve 49a Ball 49b Collar 49c Spring 50 Chuck mechanism 52 One-way clutch 53 Roller 54 Ring member 55 Fitting groove 56 Wedge piece 60A, 60B Torque limiter 62 Holding portion casing 64 Shaft coupling recess 66 Electric motor 67 Deceleration Machine 68 Output shaft 70 First outer casing 71 Bearing 72 Second outer casing 73 Screw portion 74 Power connection cord 76 Plate body (torsion bar)
78 Strain gauge 80 Non-contact torque limiter 82 Outer case 83 Permanent magnet 84 Drive shaft 85 Rotating member 86 Support member 88 Grip portion casing 88a Opening portion 89 Lid

Claims (2)

A cylindrical permanent magnet is fixedly disposed on the inner peripheral surface of the outer case, and a drive shaft is rotatably inserted in the central portion of the permanent magnet. At the outer peripheral portion of the drive shaft, an inner peripheral surface of the permanent magnet is disposed. A cylindrical magnetic member is supported and fixed in a non-contact manner, and a torque limiter formed by closing and fixing the rear end portion of the outer case with a lid,
The drive shaft of the torque limiter is surrounded and held by a sleeve, and this sleeve is supported by the outer case via a one-way clutch, and a driver bit is detachably attached to the tip of the sleeve,
The torque limiter is rotatably held by a grip casing, and the output shaft of the electric motor is coaxial with the drive shaft at the rear end of the torque limiter with respect to a lid for closing and fixing the outer case. Detachably coupled,
The outer periphery of the electric motor is surrounded by an outer casing, and the outer casing is detachably coupled to the gripping casing that holds the torque limiter.
Further, the rear end portion of the electric motor is fixed in the outer casing via a flat plate extending coaxially therewith, and a torque gauge is measured by attaching a strain gauge to one side of the plate. An electric motor driven torque fixed type driver characterized by being configured to obtain. A reduction gear is coupled to the output shaft of the electric motor, and the output shaft of the reduction gear is detachably coupled to the lid that closes the outer case of the torque limiter so as to be coaxial with the drive shaft. The electric motor drive type torque fixed type driver according to claim 1 .

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