JPH0639862Y2 - Nutrunner tightening management device - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to a nut runner that manages whether a tightening bolt and a nut mounted on a member to be tightened using a nut runner are in a predetermined tightened state. Regarding tightening management device.

(Prior art) Attach the tightening bolt and nut to the tightened member,
There is known a device that automates the tightening work and constantly manages the tightening in a predetermined state.

The nut runner with the tightening force control device automatically tightens the nut 4 on the bolt on the member to be tightened, and at the same time manages the quality of the tightened state. That is, this type of nut runner applies tightening torque to the nut side, detects the actual tightening torque and tightening angle value at the time of tightening, and, for example, as shown in FIG. 5, tightening torque composed of tightening torque and tightening angle. The inclination α of the locus is obtained, and it is determined from the inclination α of the tightening locus whether or not the bolt and nut are tightened properly without any inconvenience such as seizure or defective meshing.

The tightening process of the bolts and nuts is performed according to each condition of the elastic range tightening process or the plastic range tightening process, and the allowable width of the inclination θ of the tightening locus that determines the appropriateness of each tightening is also set. Becomes

(Problems to be solved by the invention) By the way, this type of nutrunner tightening management device can calculate a torque rate that is a tightening torque ΔT per a predetermined tightening angle Δθ at each point. The torque rate information itself has variations, and as a result, the permissible range is widened, which makes it difficult to accurately perform tightening management such as directly determining whether tightening is appropriate.

An object of the present invention is to provide a nut runner tightening management device capable of accurately determining whether or not nut tightening is appropriate.

(Means for Solving the Problem) In order to achieve the above-mentioned object, a tightening management device for a nut runner according to the present invention is a nut runner that applies a tightening force to a tightening bolt and a nut screwed to the bolt, A torque sensor for outputting torque information according to the tightening force, a tightening angle sensor for outputting tightening angle information according to the tightening force, and a torque rate calculating means for calculating a torque rate which is a tightening torque per the predetermined tightening angle. And a comparison value calculating means for calculating a comparison value of both torque rates at the set snag point and the setting control point obtained by the torque rate calculating means, and when the comparison value of the torque rate is out of the setting range, It is characterized by having a judgment control means for judging a tightening failure.

(Operation) When tightening the nut by the nut runner, the torque rate calculation means sequentially calculates the torque rate at a predetermined time point, and the comparison value calculation means calculates the comparison value of both torque rates at the set snag point and the set control point. When the comparison value of the torque rate deviates from the set range by the judgment control means, the tightening failure is judged.

(Embodiment) The nut runner tightening management device shown in FIG. 1 includes a nut runner 10 and a tightening control panel 11 for controlling the nut runner 10.

The nut runner 10 is capable of automatically tightening a nut 14 screwed into a bolt 13 inserted in a member 12 to be tightened with a predetermined tightening torque at a predetermined tightening angle, and a socket 15 fitted to the nut 14. The motor 17 whose rotation is controlled by the controller 16 of the tightening control panel 11 and this motor
Gear train 19 that transmits rotational force from drive shaft 18 of 17 to socket 15
It consists of and.

In particular, a rotation angle sensor 20 that detects a tightening angle is attached to the socket 15 side, and a strain gauge 21 that outputs tightening torque information is attached to the drive shaft 18 side. The outputs of both sensors are input to the controller 16.

The controller 16 is composed of a micro-computer, and a central processing unit (hereinafter referred to as CPU) 161 as its main part.
Equipped with. The CPU is configured so that the detection signal from the strain gauge 21 is input via the input interface 162 and the A / D converter 163, and the detection signal from the rotation angle sensor 20 is input via the input interface 164. . CPU
Exchanges data with a ROM 165 that stores program data and fixed value data and a rewritable RAM 166 that can be updated via a bus line.

Further, the motor drive signal from the CPU 161 is output to the motor 17 via the driver 167, and the display signal is output by the driver 168.
Is output to each indicator light via. The CPU 161 drives the motor drive signal to perform feedback control processing to maintain the specified rotation speed.
Output to 167. Therefore, here, the tightening angle θ
And the elapsed time have a proportional relationship.

Here, the function of the controller 16 is shown in a functional block diagram in FIG.

First, according to the tightening torque information T and the tightening angle information θ that are input, the torque rate calculating means 24 calculates a torque rate ΔT / Δθ that is a tightening torque ΔT per a predetermined tightening angle Δθ.

Here, for each preset sampling time Δt,
Find the tightening torque. In particular, a predetermined tightening angle Δθ1 is calculated from each tightening angle at time t1 (see FIG. 3) when the preset snag torque Ts is reached (see FIG. 3) and at time t2 after sampling time Δt from that time, and sampling is performed from time t1 and thereafter. The increment ΔT1 of each tightening torque at time t2 after the time Δt is calculated, and the ratio | ΔT1 / Δθ1 | of these is calculated as the torque rate at the snag point sp.

Similarly, the specified tightening angle θA from the snag point sp
When the control point cp is reached after only t4,
And a predetermined tightening angle Δθ2 is calculated from each tightening angle at time t3 before the sampling time Δt,
t3 and the increment ΔT2 of each tightening torque at time t4 after the sampling time Δt from it are calculated, and the ratio | ΔT2 / Δθ2 |
Is calculated as the torque rate.

Next, based on both torque rates at the set snag point sp and the set control point cp obtained by the torque rate calculation means 24, the comparison value calculation means 25 calculates a difference which is a comparison value of both torque rates.

That is, the comparison value calculating means 25 has | Δθ1 / Δθ1 | − |
ΔT2 / Δθ2 | = 2 | = α is calculated as a comparison value.

The tightening determination means 26 determines whether or not the comparison value α is within the preset proper tightening range β, and outputs tightening failure information.

Here, the tightening according to the tightening in the elastic region is assured, that is, it is determined whether or not the tightening locus, which is the torque-angle gradient during the final tightening, exhibits a predetermined straightness. Therefore, the proper tightening range β for determining the straightness is set in advance.

In the case of continuous tightening in the plastic region, in the plastic region tightening region, instead of setting the tightening aptitude region β, the allowable width of the torque rate at each point is set in advance. It is desirable to manage the torque rate at each time point.

Further, the point tightening determination means 27 calculates whether or not each torque rate at both the designated points of the set snag point sp and the set control point cp is within the allowable range set for each point, and if it is outside the allowable range. Outputs a tightening failure signal.

The operation of such a nut liner tightening management device will be described with reference to the flowcharts of FIGS. 4 (a) and 4 (b).

The controller is activated by the input of the main switch on the control panel.

Here, first, the bolt inserted in the tightened member 12
Socket 14 of nut runner 10 to nut 14 that is screwed to 13
Is fitted and a tightening set is made.

Thereafter, the tightening command switch TS on the control panel is turned on to issue a tightening command, and the nut 14 is fastened to the bolt 13 at high speed. At that time, as shown in FIG. 3, the relative tightening angle θ of the nut 14 with respect to the bolt 13
The tightening torque increases with an increase in (hereinafter simply referred to as an angle θ). And this tightening torque is the seating torque
When it exceeds TO (step a2), it reaches step a3, where the time (t0-ts) from the start of high-speed tightening to the seating torque TO is within the specified time tα from the start of high-speed tightening. It is determined whether or not there was. If the time is within the specified time tα, the process proceeds to step a5, and if not, the process proceeds to step a4, and the first pilot lamp L1 displays that the seating torque time is NG.

In step a5, the output of the driver 167 is cut off to stop the nut runner 10. Then, after this point of time, wait for the set tightening stop time tβ to elapse, and if it elapses, step
Go to a7. Here, in order to start the final tightening at low speed, a predetermined output signal is given to the driver 167, whereby the motor side, that is, the socket side is driven at the set rotation speed.

Then, it is determined whether or not the tightening torque exceeds the snag torque Ts. The elapsed time from the start of the final tightening until reaching the snag torque ΔTs at time t1 is the specified time tb.
It is determined whether or not it is within the range, and if it is within the range, otherwise, the snag torque time NG is displayed on the first indicator lamp L1.

In step a10, after the time t1 when the snag torque Ts is reached, the tightening torque value is sequentially measured at every predetermined sample time Δt = t2-t1.

After this, waiting for the predetermined tightening angle ΔθA to elapse from time t1, that is, waiting for the control point cp to be reached, and when the time has elapsed, proceed to step a13, where
Cancel the tightening torque value measurement.

Thereafter, in step a14, it is determined whether or not the time from the time point t1 to the control point cp at the time point t4 is within the specified time tc, and in the aptitude, the step a16 is inadequate, that is, it takes an excessively long time. If the tightening torque value is low, the second indicator light L2 does not have enough torque.
NG is displayed.

At step a16, the time points t1, t2, t3, t4 are determined, and the torque values at these time points are respectively obtained and loaded. afterwards,
Calculate each torque rate | ΔT1 / Δθ1 |, | ΔT2 / Δθ2 | at the snag point and control point.

In step a18, it is determined whether or not the torque Tc at the control point cp has exceeded the specified value Tcα. If it exceeds, then in step a20, a torque shortage NG indication is displayed on the second indicator light L2.

At step a20, whether or not the torque rate at the snag point sp is within the allowable range, that is, | ΔT _1H / Δθ ₁ | ≦ | ΔT ₁ / Δθ ₁ | ≦ | ΔT ₁ L / Δθ
₁ | is determined, and within the allowable range, in step a22, otherwise, it is considered as elastic tightening abnormality, and the torque rate NG display at the snag point sp is displayed on the third indicator light L3.

At step a22, whether the torque rate at the control point cp is within the allowable range, that is, | ΔT _2H / Δθ ₂ | ≦ | ΔT ₂ / Δθ ₂ | ≦ | ΔT ₂ L / Δθ
₂ | is judged, and if it is within the allowable range, it is judged to be step a24, otherwise, it is considered as elastic tightening abnormality such as baking, and the third indicator light is judged.
Torque rate NG at control point cp due to L3
Is displayed.

At step a24, the difference as the comparison value of each torque rate at the control point cp and the snag point sp is
It is judged whether or not it is within the allowable value α, that is, | ΔT ₂ / Δθ ₂ |-| ΔT ₂ / Δθ ₂ | ≦ α, and if it is within the allowable value α, the tightening OK display is given by the fourth indicator light L4. If the control is completed and otherwise, it is regarded as improper elastic tightening, for example, elastic tightening abnormality such as baking, and the torque rate change amount NG is displayed by the third indicator light L3.

In this way, at the same time when the bolts and nuts are automatically tightened, an abnormality in the tightening state, for example, a tightening abnormality such as defective engagement or seizure during elastic tightening can be reliably detected.

In the above-mentioned process, the tightening specification at the control point cp, that is, whether or not the torque Tc at the control point cp exceeds the specified value Tcα is determined, and if it is below, a torque shortage NG display is used. However, instead of this, the angle method may be adopted. in this case,
An angle method may be adopted in which it is determined whether or not the tightening angle ΔθA from the snag point sp to the control point cp exceeds a specified value θcα, and if the tightening angle ΔθA falls below the specified value θcα, an NG indication of insufficient tightening angle is displayed.

Further, although the above-described tightening process is performed with an allowable value suitable for tightening in the elastic region, in the case of tightening in the plastic region subsequent to tightening in the elastic region, first, a predetermined value within the plastic region is set.
The amount of change in the torque rate at the measurement point is obtained, and it is determined whether or not the amount of change is within the set value for tightening in the plastic region. In this case as well, the same operational effects as those of the above-described embodiment can be obtained.

Further, in the above-described embodiment, the difference between the respective torque rates is adopted as the comparison value of the two different torque rates, but in some cases, the ratio of the respective torque rates is calculated, and whether or not the torque rate ratio is within the set value is determined. You may comprise so that a tightening abnormality may be discovered by this.

(Effect of the Invention) As described above, the nut liner tightening management device of the present invention calculates the change value of both torque rates at the snag point and the control point, and compares this value with the set value to change the value more than the predetermined value. When the amounts match, the tightened state of the bolt and nut can be judged as defective and can be found.

[Brief description of drawings]

FIG. 1 is a schematic overall configuration diagram of a nut runner tightening management device as one embodiment of the present invention, FIG. 2 is a block diagram of the same device, FIG. 3 is a tightening torque-angle characteristic diagram of the same device, and FIG. 4 (a) and 4 (b) are a flowchart for tightening failure detection control performed by the same apparatus, and FIG. 5 is a tightening torque-angle characteristic diagram obtained by the conventional apparatus. 10 …… Nut runner, 13 …… Bolt, 14 …… Nut,
16 ... Controller, 20 ... Rotation angle sensor, 21 ... Strain gauge, 24 ... Torque rate calculating means, 25 ... Comparative value calculating means, 26 ... Tightening judging means, 27 ... Point tightening judging means.

Claims (1)

[Scope of utility model registration request] 1. A nut runner which applies a tightening force to a tightening bolt and a nut screwed to the bolt, a torque sensor which outputs torque information corresponding to the tightening force, and a tightening angle information corresponding to the tightening force. A tightening angle sensor for outputting, a torque rate calculating means for calculating a torque rate which is a tightening torque per the predetermined tightening angle, and a set snag point and a set control point of both torque rates obtained by the torque rate calculating means. A tightening management device for a nut runner, comprising: a comparison value calculating means for calculating a comparison value; and a judgment control means for judging a tightening failure when the comparison value of the torque rate is out of a set range.