JP4149642B2 - Tightening tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tightening tool provided with an intermittent torque generating mechanism that is rotationally driven by an electric motor and generates an impact force.
[0002]
[Prior art]
As a conventional tightening tool having an intermittent torque generating mechanism, there is an oil pulse mechanism using oil pressure. This mechanism is used as a low noise type because there is no collision between metals. Further, as a tightening tool using an oil pulse mechanism driven by an electric motor, there is one disclosed in Japanese Patent Application Laid-Open No. 59-129675.
[0003]
[Problems to be solved by the invention]
With a tightening tool that uses an oil pulse mechanism, impact force is generated only in the rotation direction, so if you tighten the cross hole screw using a cross screw driver bit, the axial direction of the screw will change due to the inclination of the screw cross hole when impact torque is generated. There was a problem that the force to pull the bit out occurred, and the fitting length of the cross hole of the bit and the screw became short and it was easy to come off. Therefore, the operator was working while pressing the tool body strongly in the bit direction.
[0004]
An object of the present invention is to provide a tightening tool that is easy to use by solving the above-mentioned problems and making it difficult for a bit to be removed from a cross hole of a screw during screw tightening.
[0005]
[Means for Solving the Problems]
The object is to provide a driving unit, an intermittent torque generating mechanism in which the rotational power of the driving unit is transmitted via the speed reduction mechanism unit, and a tightening unit connected to the intermittent torque generating mechanism and a bit for tightening a fastener. The tool has a pressing means for pressing the intermittent torque generating mechanism or the bit against the non-driving part side by a reaction force generated when the fastener is tightened, and further, the pressing means is provided in the power transmission path from the speed reduction mechanism part to the bit. Is achieved.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the tightening tool which becomes a present Example is demonstrated with reference to FIGS. In FIG. 1, an electric motor 1, a speed reduction mechanism unit 3, an oil pulse mechanism 4 that is an intermittent torque generation mechanism, and an output shaft 5 are arranged in the housing 2 from the rear, and screws or the like that are fasteners are attached to the output shaft 5. A cross screw driver bit 6 for tightening is arranged to be connectable. The oil pulse mechanism 4 is of a type that utilizes oil compression. When the impact torque is generated, the motor 1 supplied with power from a rechargeable battery (not shown) is driven, and the power of the motor 1 is transmitted to the speed reduction mechanism unit 3 via the pinion 31 connected to the tip of the motor 1. Then, the oil pulse mechanism unit 4 is driven.
[0007]
FIG. 2 shows a fitting portion 9 having an engaging slope at the time of impact torque generation, that is, a pressing means for pressing the intermittent torque generation mechanism against the counter-drive portion side, and the reaction force A is applied to the deceleration mechanism portion 3 when the impact torque is generated. 2 (a) and (c) in FIG. 2 and a force Acos θ (component force of A) in a direction perpendicular to the inclined surface and a force to slide along the inclined surface by the inclination angle θ of the fitting portion 9 Asinθ (component force of A) is generated, and further a frictional force μAcosθ that prevents the force to slide is generated. At this time, a force C is generated in the axial direction (C = A (sinθ−μcosθ) cosθ) from the relationship between the reaction force A and the force Asinθ (a component force of A) that tries to slide along the slope. This force C is a force that presses the entire oil pulse mechanism 4 in the direction of the bit 6 as shown in FIG. 2C when the recess 7 on the speed reduction mechanism side cannot be moved backward, and the inclination angle θ , The force that the bit 6 tries to slip out in the axial direction at the fitting portion 61 between the bit and the screw cross hole can be offset. At this time, since the configuration of FIG. 2 is connected in a hexagonal shape, a clearance D is necessary for the convex portion 8 on the bit side so that the inclined portion 91 receives the impact torque. FIG. 2 (d) shows the fitting portion 9 that generates this series of phenomena.
[0008]
FIG. 3 shows the structure of the concavity and convexity of the fitting portion 9 in FIG. 2 in the case where the speed reduction mechanism portion side is opposite to the convex portion 71 and the bit side is opposite to the concave portion 81. Since it is configured not to move, a force pressing in the direction of the bit 6 is generated as in FIG. Further, not only the structure of the unevenness is reversed, but the same effect as in FIG. 2 can be obtained even if the shape of the fitting portion 9 is three claws as shown in FIG.
[0009]
Further, since the impact torque is intermittently generated, the vibration in the axial direction generated in the fitting portion 9 is springed behind the concave portion 7 or the convex portion 71 on the speed reduction mechanism portion side as shown in FIGS. By arranging an elastic body such as 11 or spherical rubber 12, the vibration in the axial direction on the speed reduction mechanism portion 3 side, that is, the main body side can be reduced.
[0010]
Further, if the fitting portion 9 is provided between the cross screw driver bit 6 connected to the output shaft 5 and the speed reduction mechanism portion 3, it generates a force for pushing the bit 6 in the axial direction by the force C regardless of the position. 7, even in the example in which the fitting portion 9 in FIG. 7 is provided on the output shaft 5 and the example in which the fitting portion 9 in FIG. 8 is provided in the bit 6 connected to the output shaft 5. The force at which the bit 6 tries to slip out in the axial direction at the fitting portion 61 can be offset.
[0011]
【The invention's effect】
According to the present invention, the intermittent torque generating mechanism or the pressing means that presses the bit against the non-driving portion side by the reaction force generated when the fastener is tightened is further provided in the power transmission path from the speed reduction mechanism portion to the bit. When the impact torque is generated, the reaction force when the impact torque is generated is converted into an axial force by the inclination angle of the recess or projection on the deceleration mechanism side, and the recess or projection on the bit side is pushed out in the bit direction. Force is generated inside the body, and the force that pushes the bit against the screw cross hole in the opposite direction to the force that the cross screw hole bit tries to pull out in the axial direction due to the inclination of the screw cross hole is offset. However, the fitting length of the cross hole of the bit and screw remains unchanged and this eliminates the need for the operator to work while pressing the tool body strongly in the bit direction. It is possible to provide a tool with screw tightening.
[0012]
In addition, the elastic body such as a spring or spherical rubber is used to hold the concave or convex part on the speed reduction mechanism side with a pin on the main body by restricting the movement only in the axial direction, and always urging it in the bit direction by turning the cross screw. By disposing the fitting portion on the rear side of the speed reduction mechanism portion, vibration generated by the fitting portion when an impact torque is generated can be suppressed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing a screw tightening tool according to the present invention.
FIG. 2 shows a power transmission part of a screw tightening tool according to the present invention, (a) to (b) are enlarged views of a fitting part when an impact torque is generated, and (c) is a fitting after the impact torque is generated. (D) is a perspective view of a fitting part.
FIG. 3 is an enlarged view of a main part showing a fitting part of the screw tightening tool according to the present invention.
FIG. 4 is an enlarged view of a main part showing a fitting part according to the present invention.
FIG. 5 is an enlarged view showing an example in which an elastic body is disposed behind the fitting portion according to the present invention.
FIG. 6 is an enlarged view showing another example in which an elastic body is disposed behind the fitting portion according to the present invention.
FIG. 7 is an enlarged view showing an example in which a fitting portion according to the present invention is provided on an output shaft.
FIG. 8 is an enlarged view showing an example in which a fitting portion according to the present invention is provided in a bit connected to an output shaft.
[Explanation of symbols]
1 is an electric motor, 2 is a housing, 3 is a speed reduction mechanism, 4 is an oil pulse mechanism, 5 is an output shaft, 6 is a cross screw driver bit, 7 is a recess on the speed reduction mechanism side, and 8 is a convex on the bit side. , 9 is a fitting part, 10 is a pin, 11 is a spring, 12 is a spherical rubber, 31 is a pinion, 61 is a fitting part of a bit and a screw cross hole, 71 is a convex part on the speed reduction mechanism part side, and 81 is a bit side The concave portion 91 is an inclined portion.

Claims (1)

A motor,
A speed reduction mechanism to which the power of the motor is transmitted;
The intermittent torque generation mechanism that transmits power from the speed reduction mechanism and generates impact torque in the rotation direction;
A bit to which the impact torque from the intermittent torque generating mechanism is transmitted;
A fitting portion provided separately from the intermittent torque generating mechanism portion in the torque transmission path between the speed reduction mechanism portion and the bit;
In a tightening tool with
The fitting portion is provided with a first inclined surface provided on the speed reduction mechanism portion side in the torque transmission path, and a second inclined surface provided on the bit side in the torque transmission path and engaged with the first inclined surface. A clamping tool characterized in that when the impact torque is applied between the first slope and the second slope , the second slope is pressed in the axial direction. .

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