JPH0740262A - Measuring mehtod for screw fastening - Google Patents

Abstract

PURPOSE:To carry out the fastening of a bolt by only monitoring a torque value and an angle value by performing fastening of a screw by using a motor and using the torque increase ratio to the fastening angle for the judgement of the result of the plastic region fastening in screw fastening. CONSTITUTION:When bolting for an engine of a vehicle is performed and its quality control is performed, an angle value and a torque value from the time when the torque value of a motor reaches a certain torque to the time when the torque value reaches the specified torque of the motor or the specified angle of fastening are stored after fastening of the screw is started by means of an automatic fastening machine using the motor. And the torque increase values DELTAT1, DELTAT2, DELTAT3 for showing the torque increase ratio in changing of the preset fixed angle value DELTAA are computed. And the judgement of the result of the plastic region fastening (fastening to the region beyond the elastic range of a bolt material) in fastening can be performed by detecting the fact that the final torque increase value DELTAT3 at the point C just before the screw fastening is stopped is decreased than the torque increase value DELTAT1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring screw tightening, and more particularly, for determining a result of plastic region tightening in screw tightening.
The present invention relates to a new improvement for using a torque increase rate with respect to a tightening angle.

[0002]

2. Description of the Related Art As a conventional method for measuring screw tightening of this type, generally, after tightening a bolt at a constant torque or a constant angle, the bolt is once removed to measure its longitudinal dimension. By measuring and confirming that the length of this bolt is longer than before tightening, it is confirmed that it is tightened in the plastic region (tightening to the region beyond the elastic region of the bolt material). It was

[0003]

Since the conventional screw tightening measuring method is configured as described above, the following problems exist. That is, with the method in which the bolts that have been tightened once are removed and the dimensions of the screws are compared to make a determination, it is not possible to make a determination when the bolts are actually tightened, and it is not possible to go beyond the prediction determination range.

The present invention has been made to solve the above problems, and in particular, the measurement of the screw tightening in which the torque increase rate with respect to the tightening angle is used to determine the result of the plastic region tightening in the screw tightening. The purpose is to provide a method.

[0005]

A screw tightening measuring method according to the present invention performs screw tightening of a screw by using a motor, and judges a result of a plastic region tightening in this screw tightening with respect to a tightening angle of this screw tightening. This is a method using the torque increase rate.

More specifically, after starting the screw tightening, the angle value and the torque value from the time when the torque value of the motor reaches a constant torque value to the specified torque of the motor or the specified angle of the screw tightening. Is stored, a torque increase value at the time of changing the preset constant angle value is calculated, and the condition for the determination is that the final torque increase value before stopping the screw tightening is smaller than the torque increase value. Is the method.

[0007]

In the method for measuring screw tightening according to the present invention, the angle from the time when the torque value of the motor reaches a constant torque value to the specified torque of the motor or the specified angle of the screw tightening after starting the screw tightening. Value and torque value are stored, the torque increase value at the time of a change of the preset constant angle value is calculated, and the final torque increase value immediately before stopping the screw tightening is smaller than the torque increase value. It is possible to judge the result of the plastic region tightening in screw tightening.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a screw tightening measuring method according to the present invention will be described in detail below with reference to the drawings. First, as shown in FIG. 1, for example, when bolt tightening for an engine in an automobile and quality control thereof are performed, after screw tightening of a screw is started by an automatic screw tightener using a motor (not shown), The torque value and the torque value from the time when the torque value reaches a constant torque value to the specified torque of the motor or the specified angle of the screw tightening are stored, and when the preset constant angle value ΔA changes. The torque increase values ΔT ₁ , ΔT ₂ , and ΔT ₃ indicating the torque increase rate are calculated, and the final torque increase value ΔT ₃ immediately before the stop of the screw tightening ΔT ₃ is decreased from the torque increase value ΔT _1. It is possible to determine the result of tightening in the plastic region (tightening up to a region beyond the elastic region of the bolt material) in screw tightening by detecting that the bolt is tightened.

That is, in FIG. 1, ΔT ₁ / ΔA, ΔT ₂ / ΔA, ΔT ₃ / ΔA at points A, B and C
The value of ΔT ₁ / ΔA, ΔT ₂ / ΔA> ΔT ₃ / ΔA
By confirming that the above condition is satisfied, it is possible to achieve the plastic region tightening of the screw tightening.

[0010]

Since the screw tightening measuring method according to the present invention is configured as described above, the following effects can be obtained. That is, by calculating the torque increase value at the time of a certain change in the screw tightening angle value and detecting that the final torque increase value immediately before the screw tightening is stopped is smaller than the previous torque increase value, A plastic zone tightening can be achieved. Therefore, it is not necessary to remove the bolt after tightening the screw, the tightening of each bolt can be monitored only by monitoring the torque value and the angle value, and the quality can be stabilized.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing a method for measuring screw tightening according to the present invention.

[Explanation of symbols]

△ A Angle value △ T ₁ , △ T ₂ Torque increase value △ T ₃ Final torque increase value

Claims (2)

[Claims] 1. A screw tightening measurement, characterized in that a screw is tightened with a motor, and a torque increase rate with respect to a tightening angle of the screw tightening is used to judge a result of a plastic region tightening in the screw tightening. Method. 2. After the screw tightening is started, the angle value and the torque value from the time when the torque value of the motor reaches a constant torque value to the specified torque of the motor or the specified angle of the screw tightening are stored. , The constant angle value set in advance
Calculate the torque increase value (△ T ₁ , △ T ₂ ) when (△ A) changes, and the final torque increase value (△ T ₃ ) immediately before stopping the screw tightening is the torque increase value (△ T ₁ , The screw tightening measuring method according to claim 1, wherein the condition for the determination is that it is smaller than ΔT ₂ ).