JPS6141711B2 - - Google Patents

Description

[Detailed Description of the Invention] Screws, bolts, and nuts, which are one of the disassembly connecting elements of equipment, are generally fastened using a screwdriver,
This has been done using tools such as monkey bars, spanners, and wrenches. In addition, a fastening method using compressed air is also used industrially to improve productivity.

However, the above-mentioned conventional fastening methods cause non-uniform fastening conditions in the axial direction and rotational direction of the screw mainly due to the effect of solid friction acting between the screw and bolt head and the washer. This is a problem that urgently needs to be resolved.

In order to solve such problems, the present invention actively utilizes torsional vibration during fastening. Since this is caused by solid friction between the parts, high-precision fastening is achieved by applying rotation to the fastening tool using an electric motor and applying torsional vibration, while equivalently reducing the acting solid friction. be.

In order to achieve the above object, the screw fastening method of the present invention applies superimposed direct current and alternating current to a constant speed direct current servo motor to generate a superimposed motion of unidirectional rotational motion and torsional vibration on the motor shaft. The superimposed motion is transmitted through a resonant elastic rod connected and fixed to the motor shaft.
The screw fastening device of the present invention is characterized in that the screw fastening tool of the present invention is transmitted to a screw fastening tool that is integrated with or fixedly connected to the elastic rod, and is engaged with the screw fastening tool to fasten the screw member. A constant-speed DC servo motor is configured to generate a superimposed motion of unidirectional rotational motion and torsional vibration on the motor shaft by applying a superimposed amount of current and alternating current; It consists of a resonant elastic rod, and a screw fastening tool that is integrated with or connected to and fixed to the resonant elastic rod.

Next, specific embodiments of the present invention will be described with reference to the drawings. In FIG. 1, 1 is a constant-speed DC servo motor that applies direct current and alternating current in a superimposed manner to generate a superimposed motion of, for example, clockwise unidirectional rotational motion and torsional vibration on the motor shaft 2; 3 is a constant-speed DC servo motor; An elastic rod for torsional resonance, 4 a driver, 5 a cross-recessed bolt (screw), 6 a washer, and 7 a nut portion. In addition, in Figures 2 and 3, 8, 10
9 represents a hexagonal socket wrench attached to the elastic rod 3 for torsional resonance, 9 represents a hexagonal bolt, and 11 represents a hexagonal socket bolt.

Referring to FIG. 1, the principle of operation of the present invention will be described. Fastening a bolt (screw) 5 by applying a superimposed motion of unidirectional rotational motion and torsional vibration to a screw fastening tool, for example, a driver 4, is performed at a constant speed. This is achieved by applying a superimposed direct current and alternating current to the direct current servo motor 1 to generate a superimposed motion of unidirectional rotational motion and torsional vibration on the motor shaft 2.

The fastening torque one-hour curve when only direct current is applied to the constant speed DC servo motor 1 is as shown in curve A in Fig. 4, and screw fastening using a normal electric screw fastening device follows this fastening torque curve. It is also accomplished with a fastening torque that depends on A.

However, as in the present invention, the constant speed DC servo
As shown in Fig. 5, the fastening torque one-hour curve when direct current and alternating current are applied to the motor 1 in a superimposed manner is as shown in curve B, where the vibration curve is superimposed on the curve A, and as a result, the motor shaft 2, a superimposed motion of unidirectional rotational motion and torsional vibration is generated. When screw fastening is performed by transmitting the superimposed motion of unidirectional rotational motion and torsional vibration generated in the motor shaft 2 to a fastening tool, the bolt (screw) 5 to be fastened has a high tightening torque just before the end of fastening. However, the fastening tool (driver 4) and the rotating rotor of the electric motor 1 are connected by a suitable elastic rod 3, and the resulting torsional resonance system (for example,
The natural torsional frequency coincides with the commercial power frequency). Therefore, since the electric motor is accompanied by torsional vibration while rotating, the solid friction acting between the bolt (screw) 5, washer 6, and nut portion 7 is equivalently reduced, and high-precision fastening is required. This eliminates the drawback of using screws or bolts with diameters larger than necessary due to non-uniformity of tightening force in the axial direction, and it becomes possible to design with appropriate tolerances. The operating principle in FIGS. 2 and 3 is also the same as that in FIG. 1.

As described above, the present invention is a new and useful invention that can solve some of the problems associated with screw fastening.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are explanatory diagrams showing an embodiment of the screw fastening device of the present invention, and Figure 4 is an explanatory diagram showing an example of the screw fastening device of the present invention. Fastening Torque-Time Curve Diagram FIG. 5 is a fastening torque-time curve diagram when screw fastening is performed by superimposing direct current and alternating current to a constant speed DC servo motor. 1 is a constant speed DC servo motor, 2 is the motor shaft,
3 is an elastic rod for torsional resonance, 4 is a driver, 5 is a cross-recessed bolt, 6 is a washer, 7 is a nut part, 8 is a hexagonal wrench, 9 is a hexagonal bolt, 10 is a hexagonal socket wrench, 11 is a hexagonal socket bolt.

Claims (1)

[Scope of Claims] 1. Direct current and alternating current are superimposedly applied to a constant speed DC servo motor to generate a superimposed motion of unidirectional rotational motion and torsional vibration on the motor shaft, and the superimposed motion is applied to the motor shaft. A screw fastening method characterized by transmitting a signal through a connected and fixed resonance elastic rod to a screw fastening tool that is integrated with or connected and fixed to the elastic rod, and fastening a screw member that engages with the screw fastening tool. . 2. A constant-speed DC servo motor that applies DC and AC in a superimposed manner to generate a superimposed motion of unidirectional rotational motion and torsional vibration on the motor shaft, and is connected to the motor shaft of the constant-speed DC servo motor. A screw fastening device comprising a fixed elastic rod for resonance and a screw fastening tool fixed integrally with or connected to the elastic rod for resonance.