JP2002071487A - Joint coefficient measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint coefficient measuring instrument for measuring a joint coefficient indicating a tightening degree of a screw to tighten objects to be tightened, with higher measuring accuracy in particular. SOLUTION: This instrument has a torque sensor to detect the tightening torque value in tightening a screw and an anglar speed sensor to detect rotation anglar speed in screwing work, capable of calculating the joint coefficient against the tightening screw from the screw rotation angle to be obtained by integrating the tightening torque value acting after complete screwing up together with rotation angle speed corresponding to the relative tightening torque, as well as the capability in obtaining the anticipated completion time of screw-tightening works.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint coefficient measuring instrument which can be used to measure a joint coefficient and indicates a screwing hardness (tightening hardness) of a screw fastened to an object to be fastened. The present invention relates to a joint coefficient measuring device capable of measuring a coefficient with high accuracy.

[0002]

2. Description of the Related Art A joint coefficient is a term indicating the degree of tightening of a screw at the time of screw fastening work, and the joint coefficient can be obtained by a screw fastening torque value with respect to a screw rotation angle at the time of screw fastening.

That is, the joint coefficient e is obtained by the following equation.

E = 1 / T ₀ × (dT / dn) T = T ₀ where n is the number of rotations of the screw T ₀ : the tightening torque of the screw For example, a bolt having a nominal screw size of M8 and a tightening torque T: 13. An example of the actual measurement of the joint coefficient when the joint is to be fastened at 4 N · m will be described with reference to FIG. 4. The following index is provided.

Then, the measuring bolt is tightened to 80% of the tightening torque value T, that is, 0.8T (10.7 N ·
m) and the indicated value of the protractor is set to “0” at this fastening position. Next, tightening is performed until T: (13.4 N · m), and the rotation angle Δθ of the measuring bolt at that time is read.

Then, the angle Δθ is substituted into the formula e = 72 / Δθ of the joint actual measurement method, and e = 72 / 7.2 = 10 (when Δθ (practical value) = 7.2 degrees) is obtained.

The value of the joint e thus obtained is e
If <5, it is determined as a soft joint, and e 、 1
When it is 0, it is judged as a normal joint, and e> 20.
If it is, it is determined to be a hard joint.

[0008]

As described above, the conventional joint coefficient measuring means is a simple method using a protractor, and is shown, for example, in FIG. 2 showing the relationship between the fastening torque T and the rotation angle of the measuring bolt. Thus, the change value of the rotation angle of the measurement bolt from the 0.8T value to the T value of the fastening torque of the measurement bolt is represented by a straight line a, and the rotation angle with respect to the change value of the fastening torque is based on the straight line a. However, there is a problem that it is not possible to detect a highly accurate joint coefficient since the change value of the joint is estimated.

Further, as described above, the protractor and the joint coefficient detecting means using the index indicating the protractor rely on the visual observation of the screw-fastening operator, so that an error in reading the indicated value easily occurs. For this reason, accurate calculation of the joint coefficient cannot be obtained.

The present invention has been made in view of such a conventional problem. A sensor capable of electrically detecting a joint coefficient, a fastening torque of a measuring bolt (fastening screw), and a rotational angular velocity of the measuring bolt. By integrating the angular velocity of the measuring bolt with respect to the fastening torque value obtained by the sensor to calculate the rotation angle, a joint coefficient measuring device capable of electrically determining and displaying a highly accurate joint coefficient value is provided. The provision is the first purpose.

According to the present invention, there is provided a joint coefficient measuring device capable of calculating and displaying a fastening operation time for each fastening screw required to fasten the fastening screw based on the joint coefficient value. Aim.

[0012]

In order to achieve the first object, according to the first aspect of the present invention, a torque sensor for detecting a fastening torque value at the time of screw fastening and a screw rotation angular velocity at the time of screw fastening are detected. Having an angular velocity sensor that performs, after a fastening torque value acting after the fastening screw is seated, and calculating a joint coefficient for the fastening screw from a screw rotation angle obtained by integrating a rotation angular velocity corresponding to the fastening torque value, And a joint coefficient measuring device for displaying.

According to a second aspect of the present invention, there is provided a torque sensor for detecting a fastening torque value when a screw is fastened, and an angular velocity sensor for sensing a screw rotation angular speed when the screw is fastened. A joint coefficient for the fastening screw is calculated from a fastening torque value acting after the fastening screw is seated and a screw rotation angle obtained by integrating a rotation angular velocity corresponding to the fastening torque value. It is characterized by being a joint coefficient measuring device for obtaining the fastening operation time.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings. In the present embodiment, a joint coefficient measuring device is configured by a combination of a preset type torque wrench, an angular velocity sensor, and a controller. A schematic configuration of the joint coefficient measuring device will be described below with reference to FIG.

Reference numeral 1 denotes a preset torque wrench provided with a torque setting mechanism 2 (hereinafter simply referred to as a wrench). The wrench 1 includes an angular velocity sensor 3 such as a gyroscope. It is assembled. A torque setting device 3 is provided. The handle 4 of the wrench 1
A head portion 5 is pivotally supported at the front end portion of the device, and a ratchet shaft 6 is used for the head portion 5. A socket 8 to be engaged with a screw 7 to be fastened is connected to the tip of the ratchet shaft 6. 9 is a controller having a control circuit 10 shown in FIG.
Fixedly held.

The control circuit 10 includes a strain gauge 11, an amplifier 12, an AD converter 13 and an arithmetic processing circuit 14 for measuring the fastening torque of the screw, an angular velocity sensor 15 for measuring the fastening angle of the screw, and an amplifier 16 , An AD converter 17, an arithmetic processing circuit 14, a memory 18 for storing the tightening torque value Tn and the tightening angle value θn obtained by the arithmetic processing circuit 14, and a tightening torque value Tn obtained by the arithmetic processing circuit 14. And a display circuit 19 and a display unit 20 for displaying the joint coefficient calculated from the tightening angle value θn.

The procedure for measuring the joint coefficient using the wrench 1 will be described with reference to the flowchart shown in FIG.

First, after the snag torque is set by using the torque setting mechanism 2 of the wrench 1 and the wrench 1 is prepared, tightening of a screw (not shown) is started using the wrench 1.

The tightening torque of the screw is converted into a torque value via a strain gauge and an AD converter in the control circuit 10. The converted torque value is compared with a set torque value (snag torque value). When the converted torque value (current torque value) exceeds the snag torque value, angle measurement starts, and the angular velocity in the control circuit 10 is changed. Drift correction of the angular velocity value input from the sensor and the AD converter is performed, and the result is integrated to calculate the screw fastening angle.
The thus obtained torque value for an arbitrary angle θn is represented by R
Record and save in AM (random access memory).

It is detected whether or not the rotation angle of the screw by the wrench has reached a set angle. When the rotation angle reaches the set angle, a tightening completion signal is output and an alarm is displayed by a buzzer or an indicator lamp. Things.

The characteristic coefficient of the joint coefficient is calculated from the change in the rotation angle θn of the screw with respect to the tightening torque value Tn during the tightening operation, and the joint coefficient is calculated by standardizing the characteristic slope. In this way, according to the joint coefficient measuring means that electrically and automatically calculates the joint coefficient using the control circuit 10, compared to a conventional actual measurement example of the joint coefficient as shown in FIG. A highly accurate joint coefficient can be obtained.

Based on the joint coefficient thus obtained, a screw tightening operator having a predetermined screw tightening operation speed determines a screw tightening operation time to be performed until the screw tightening operator reaches a predetermined screw tightening angle (fastening torque) value. However, in the present embodiment, since the accuracy of the joint coefficient to be obtained can be increased, the screw tightening operation time of a predetermined screw tightening operator is accurately obtained based on the joint coefficient with high accuracy. be able to.

In the above embodiment, a conventional preset torque wrench is applied to the mechanism as the joint coefficient measuring device, but the present invention is not limited to this mechanism.

[0024]

As described above, according to the joint coefficient measuring device of the first aspect of the present invention, the measurement accuracy of the joint coefficient can be improved. According to the second aspect of the present invention, it is possible to accurately calculate a required time until completion of fastening of a predetermined screw by a predetermined screw tightening operator, and to effectively manage screw tightening work based on the required time. Can do it.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a joint coefficient measuring device according to the present invention.

FIG. 2 is a block diagram of a control circuit provided in the joint coefficient measuring device according to the present invention.

FIG. 3 is a flowchart for measuring a joint coefficient by a joint coefficient measuring device according to the present invention;

FIG. 4 is a characteristic diagram of a measurement example of a conventional joint coefficient.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wrench 2 Torque setting mechanism 3 Angular velocity sensor 4 Handle part 5 Head part 6 Ratchet shaft 7 Fastened screw 8 Socket 9 Controller 10 Control circuit 11 Strain gauge 12 Amplifier 13 AD converter 14 Arithmetic processing circuit 15 Angular velocity sensor 16 Amplifier 17 AD converter 18 memory 19 display circuit 20 display unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsunehiko Teshima 2-2-12 Omorikita, Ota-ku, Tokyo Inside Tonichi Works Co., Ltd. (72) Inventor Yasuhiro Yamamoto 2-2-1 Omorikita, Ota-ku, Tokyo No. Inside the Tohnichi Seisakusho Co., Ltd. (72) Inventor Nobuyoshi Kobayashi 2-2-1 Omorikita, Ota-ku, Tokyo F-term inside the Tonichi Seisakusho (reference) 2F051 AA00 AB06 AC09 BA03

Claims (2)

[Claims] 1. A torque sensor for detecting a fastening torque value at the time of screw fastening, an angular velocity sensor for detecting a screw rotational angular speed at the time of screw fastening, and a fastening torque value acting after a fastening screw is seated; A joint coefficient measuring device which calculates and displays a joint coefficient for a fastening screw from a screw rotation angle obtained by integrating a rotation angular velocity corresponding to a value. 2. A torque sensor for detecting a fastening torque value at the time of screw fastening, an angular velocity sensor for detecting a screw rotational angular speed at the time of screw fastening, a fastening torque value acting after the fastening screw is seated, and the fastening torque A joint coefficient measuring device comprising: calculating a joint coefficient for a fastening screw from a screw rotation angle obtained by integrating a rotation angular velocity corresponding to a value; and calculating an estimated screw fastening work time from the joint coefficient.