JP2002066945A - Drift correcting method of angular velocity sensor in torque wrench employing screw tightening angle method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically and rapidly correct the time drift and the temperature drift in an angular velocity sensor. SOLUTION: After the power is applied to the angular velocity sensor fitted to a screw tightening wrench, the condition of fluctuation of the angular velocity forming the reference angular velocity of the angular velocity sensor is detected corresponding to the elapse of time and the change of temperature while maintaining the screw tightening wrench in a stationary condition, the time drift and the temperature drift in the stationary condition of the wrench are recorded, and the angular velocity corresponding to each time and each temperature when performing the angular tightening by the screw tightening wrench is automatically corrected based on the time drift and the temperature drift.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting a time drift and a temperature drift of an angular velocity sensor provided in a screw fastening wrench used in a screw fastening operation employing an angle method. The present invention relates to a method for correcting drift of an angular velocity sensor, which can automatically and quickly perform correction, thereby improving the accuracy of angle tightening.

[0002]

2. Description of the Related Art For example, several to several tens of fastening screws (including bolts and nuts) are attached to, for example, an engine cylinder head, a wheel base, and the like (hereinafter, these are referred to as objects to be fastened).
On the other hand, at the time of screw tightening work in which the screw is tightened by adopting the angle tightening method, a torque wrench equipped with an angular velocity sensor is required to detect the screw tightening angle. The torque wrench provided is used.

Thus, the characteristics of a general angular velocity sensor used in a torque wrench include a time drift in which the angular velocity value fluctuates when a predetermined time elapses after power is applied to the angular velocity sensor, and a characteristic of the screw. It has a temperature drift in which the angular velocity value (output) fluctuates due to a temperature change or the like in the environment where the fastening wrench is used.

Therefore, in order to increase the accuracy of screw tightening with a torque wrench equipped with an angular velocity sensor having these drift characteristics, a measured value of a fastening angle obtained at the time of angular tightening using the angular velocity sensor is required. It is necessary to make correction based on the time drift characteristic inherent in the angular velocity sensor and the temperature drift characteristic accompanying a temperature change in the use environment.

[0005]

Accordingly, in the prior art for correcting the time drift and the temperature drift in the angular velocity sensor provided in the screw fastening wrench, the angular velocity sensor is maintained in a stationary state before the measurement, for example, by a variable resistor. Manual correction means for manually correcting drift using a device or the like.

[0006] Therefore, in the manual correction of the drift, it takes time and trouble to complete the correction, and it is difficult to perform high-precision correction. Therefore, the correction between the correction value and the measured value is difficult. An error occurs, and it is difficult to detect the fastening angle with high accuracy due to the error.

The present invention automatically detects and corrects drift of an angular velocity sensor used in a torque wrench in order to perform highly accurate drift correction that does not compensate for the drawbacks caused by the conventional manual drift correction. It is an object of the present invention to make it possible to speed up correction and to perform highly accurate angle detection.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, after a power supply is applied to an angular velocity sensor provided in a screw fastening torque wrench adopting the angle method, the power is applied to the screw. While holding the fastening wrench in a stationary state, an angular velocity value fluctuation state serving as a reference of the angular velocity value of the angular velocity sensor is detected in response to the passage of time, and a time drift value of the wrench stationary state is recorded, and the screw This is a drift correction method for an angular velocity sensor in a torque wrench that employs a screw fastening angle method that automatically corrects an angle value corresponding to each time from power-on at the time of angle tightening by a fastening wrench based on the time drift value. It is characterized by:

According to a second aspect of the present invention, the screw tightening torque wrench provided with the angular velocity sensor is maintained in a stationary state, and a reference angular velocity value by the angular velocity sensor in a stationary state at a certain time and a predetermined time after Angular velocity values are recorded, and when the angular velocity drift amount, which is the difference between the angular velocity values, is within a specified range, it is regarded as a temperature drift, and the temperature drift is automatically corrected by replacing the angular velocity value with a recorded angular velocity value after a fixed time. The invention is characterized in that it is a drift correction method for an angular velocity sensor in a torque wrench employing a screw fastening angle method.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

In FIG. 5, reference numeral 1 denotes an example of a preset type torque wrench (hereinafter simply referred to as a wrench) which can be used for measuring a fastening torque of a fastening screw. Wrench 1 has angular velocity sensor 2
And a controller 3 for recording a time drift and a temperature drift based on the output from the angle sensor.
Reference numeral 4 denotes a handle of the wrench 1.
The head part 5 is pivotally supported, and a ratchet shaft 6 is expended on the head part 5. A socket 8 to be engaged with a screw 7 to be fastened is connected to the tip of the ratchet shaft 6. Since the present invention does not feature the wrench structure, detailed description of the wrench structure will be omitted.

When the fastening angle value of the screw 7 to be fastened is measured using the wrench 1 having the above structure, the time drift and the temperature drift of the angular velocity sensor provided in the wrench vary for each angular velocity sensor. Therefore, unless this variation is corrected, a highly accurate fastening torque value cannot be measured. Therefore, drift correction of the angular velocity sensor used in the wrench is required. Hereinafter, this drift correction method will be described.

First, when manufacturing a wrench having an angle sensor, the time drift characteristics of the angular velocity sensor 2 provided in the wrench 1 are recorded. As shown in the flowchart of FIG. 1, the procedure for recording the time drift characteristic is as follows. The angular velocity sensor 2 is powered on and activated, and the angular velocity value is sampled at regular time intervals from the activation, and each sample number (N) is sampled. The angular velocity value (ωn) with respect to
As a result, the time drift data (variation curve of the angular velocity with respect to time) indicated by the line A in FIG. 3 is stored in the controller 3.

Therefore, when measuring the fastening torque value of the fastening screw using the wrench 1, first, power is turned on to the angular velocity sensor 2 of the torque wrench, and the time drift data already stored in the controller 3 is stored. Is read, and based on the time drift data, the measured angular velocity value associated with the elapsed time after the power is applied following the measurement of the fastening torque by the wrench is corrected by the correction curve (B).

As described above, the angular velocity change with time after turning on the power of the angular velocity sensor provided in the wrench used for measuring the fastening torque at the time of stopping (when no angular velocity is given), that is, time drift data Is stored by the controller provided in the wrench, and when the wrench is used to measure the fastening torque value of the fastening screw by using the angle method, the wrench is used to store the fastening torque value. The above-mentioned time drift data is read out, and the measurement angle value is automatically (electrically) corrected in accordance with the elapse of the measurement time by the wrench.

Next, the temperature drift correction of the angular velocity sensor will be described.

In this temperature drift correction, as shown in the flowchart of FIG. 2, first, a wrench provided with an angular velocity sensor is placed in a stationary state, an angular velocity value (ω1) at a certain time is detected and recorded, and a constant value is obtained. Drift data is obtained by detecting and recording the angular velocity value after time,
This drift data is stored and stored in the controller 3.

Next, in order to determine whether the drift data, which is a change in the angular velocity, is due to temperature or actual angular tightening, the angular velocity change (Δ
ω) is detected. Thus, it is determined whether the angular velocity change is equal to or less than a specified angular velocity change. If the angular velocity change is not more than the specified angular velocity, it is determined that the change is due to a temperature change.

Then, the measured value is automatically (electrically) corrected by replacing the reference angular velocity value with the angular velocity value (ω1) after a predetermined time.

As described above, by correcting the time drift and the temperature drift of the angular velocity sensor provided in the wrench, the angle tightening accuracy of the screw tightening operation using the angle method can be improved.

[0021]

As described above, according to the drift correction method according to the first aspect of the present invention, the time drift correction of the angular velocity sensor provided in the torque wrench is automatically (electrically) performed. Can be. Further, claim 2 of the present invention
According to the drift correction method described in (1), drift correction of the angular velocity of the angular velocity sensor provided in the torque reticule can be automatically performed. Therefore, according to the present invention, angle tightening of a screw by a wrench using an angular velocity sensor can be easily and quickly performed at a set angle with high accuracy.

[Brief description of the drawings]

FIG. 1 is a flowchart of time drift correction according to the present invention.

FIG. 2 is a flowchart of temperature drift correction according to the present invention.

FIG. 3 is a schematic diagram of a torque wrench provided with an angular velocity sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Torque wrench 2 Angular velocity sensor 3 Controller 4 Handle part 5 Head part 6 Ratchet shaft 7 Fastened screw 8 Socket

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuhiro Yamamoto 2-2-1, Omorikita, Ota-ku, Tokyo Inside Tonichi Works Co., Ltd. (72) Inventor Nobuyoshi Kobayashi 2-2-1, Omorikita, Ota-ku, Tokyo No. F Co., Ltd. F-term (Reference) 3C038 AA01 AA03 AA04 BC01 CA06 CA07 CA10 CB02 EA01 EA02 EA04 EA06

Claims (2)

[Claims] After applying power to an angular velocity sensor provided in a screw fastening torque wrench employing an angle method, an angular velocity which is a reference of an angular velocity value of the angular velocity sensor while holding the screw fastening wrench in a stationary state. The value fluctuation state is detected in response to the passage of time, the time drift value in the wrench stationary state is recorded, and the angle value corresponding to each time from power-on when the screw is tightened by the screw fastening wrench is calculated as the time A drift correction method for an angular velocity sensor in a torque wrench employing a screw fastening angle method, wherein the correction is automatically performed based on the drift value. 2. A screw tightening torque wrench provided with an angular velocity sensor is maintained in a stationary state, and a reference angular velocity value by the angular velocity sensor in a stationary state at a certain time and an angular velocity value after a predetermined time are recorded. If the amount of angular velocity drift, which is the difference between the angular velocity values, is within the specified range, it is regarded as the temperature drift, and the temperature drift is automatically corrected by replacing it with the angular velocity value recorded after a certain period of time. A method for correcting a drift of an angular velocity sensor in a torque wrench employing an angle method.