JPS6244605B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a torsion detection device used in a load torque detection device or the like.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torsion detection device used in a load torque detection device and the like.

Prior Art The present applicant has previously filed various applications for torsion detection devices used in load torque detection devices and the like. This type of torsion detection device connects a driving shaft connected to a motor or the like and a driven shaft to which a tool or the like is attached to the tip with a torsion shaft element such as a torsion bar. It was designed to detect the relative angular displacement of the driven shaft. Specifically, a rotating disk having a large number of slits formed on the same circumferential surface centered around the driven shaft is attached to the driven shaft, and a shielding plate having a slit shielding portion is attached to the driving shaft. The number of slits that can be detected by the photocoupler placed opposite to the rotating disk increases or decreases in accordance with the relative angular displacement each time the rotating disk rotates once. , the number of rotational passages at that time, that is, the number of slits that were not shielded, was determined as the amount of twist.

However, when the rotation speed of the driving shaft is low, the photocoupler reliably detects the rotational passage of each slit,
It is possible to output the output signal SG1 at a predetermined level Vs to the next stage, such as a comparator or counter that removes noise and determines whether or not the slit has passed, to ensure its operation, but as the rotation speed increases, Since the time for the slit to pass through the photocoupler becomes shorter, the amount of light received by the photodetector of the photocoupler decreases, and the photocoupler outputs an output signal SG1 with a short waveform and below the predetermined level Vs. Therefore, detection errors are more likely to occur.

In particular, at the start of detection of passage through the slit for each rotation of the rotating disk, that is, after the passage of the slit in the previous rotation is detected, after a predetermined period of time has elapsed, the slit that will pass first in the next rotation or several slits from that slit will be detected. During the detection of passage, since the rise characteristics of the photodetector of the photocoupler are poor, the output signal from the photocoupler remains completely off even when the first slit or the next few slits pass at high speed. SG1
becomes below a predetermined level Vs as shown in FIG. Therefore, several slits cannot be reliably detected at the start of slit passage detection, resulting in detection errors.

An object of the present invention is to solve the above-mentioned problems and provide a torsion amount detection device that can accurately and reliably detect the amount of torsion of a driven shaft relative to a driving shaft over a wide range from low to high rotational speeds. It is on offer.

Embodiment Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings.

In FIG. 2, a driving shaft 1 has a shaft portion 2 and a cylindrical portion 3 connected and fixed to each other with a fixing bolt 4, and is rotatably supported by a case 5. The pulley 6 is connected and fixed to the shaft portion 2 of the drive shaft 1 by a fixing bolt 7, and transmits rotational drive of a motor or the like to the drive shaft 1 via a belt (not shown).

The cylindrical driven shaft 8 is rotatably supported by the case 5 at its base end, is disposed on the same axis as the driving shaft 1, and is inserted into the driving shaft 1 by a sliding ring 9 at its distal end. is supported for relative rotation. The driven shaft 10 has a tool such as a drill attached to its tip (not shown), and its base end is inserted into the driven shaft 8, and is connected to the driven shaft 8 by a spline 11a and a spline key 11b. They are connected so that they can rotate integrally and move relative to each other in the axial direction.

Transmission spring 12 as rotational motion transmission means
is concentrically wound around the driven shaft 8 with a slight gap, one end of which is connected and fixed to the base end of the cylindrical part 3, and the other end is connected and fixed to the flange part 8a of the driven shaft 8. The rotating force of the driving shaft 1 is transmitted to the driven shaft 8. Note that when a very large load torque is applied to the driven shaft 10 and the driving shaft 1 is displaced 360° in the rotational direction (one rotation) with respect to the driven shaft 8, the transmission spring 12 is twisted and the driven shaft 8
It is designed to wrap around the outer circumferential surface of.

The rotating disk 13 is attached to the tip of the cylindrical portion 3 of the driving shaft 1 with a screw 14, and rotates together with the driving shaft 1. As shown in FIG. 3, the rotating disk 13 has 87 slits 15 that are movable at an angle of approximately 180° in the counter-rotational direction from a predetermined reference position P on the disk 13. The transparent area of the first slit (hereinafter referred to as the leading slit) 15a located at the reference position P of each slit 15 is adjacent to another slit that is transparently provided on the same circumference centering on the axis of the shaft 1. The next slit 15 is formed to be larger than the opening area of slit 15 and is spaced 1.5 degrees from the leading slit 15a, and up to 70 slits are formed with the same opening area and at equal angular intervals of 1.5 degrees,
The subsequent slits 15 are attached to their rotational direction side edges 1.
5f is formed so that the interval between them becomes exponentially wider in the counter-rotation direction, and the transparent area thereof gradually becomes larger.

Further, the rotating disk 13 has the leading slit 15.
Fourteen fan-shaped through holes 16 are continuously formed on the same circumference around the axis of the driving shaft 1 from a position displaced by an angle of approximately 131° in the counter-rotation direction of the disc 13 with respect to a. has been done.

The shielding plate 17 is fixed to the flange portion 8a of the driven shaft 8 with screws 18 so as to face the rotating disk 13, and rotates together with the driven shaft 8. In this embodiment, when the shielding plate 17 faces the rotating disk 13 as shown in FIG.
a slit shielding section 19 that shields the slit 15;
and a through-hole shielding part 20 that shields the through-hole 16;
A reference hole 21 facing the transparent position of the through hole 16
is formed. Moreover, the shielding plate 17 with respect to the rotating disk 13 is arranged so that when the driving shaft 1 is in a stopped state,
The relative position (in this example,
The 31st and subsequent slits 15 are slit shielding parts 19
It is arranged so that it is a position that is shielded by

The angular displacement detection photocoupler 22 and the reset photocoupler 23 are disposed inside the case 5 via a support member 24, and the angular displacement detection photocoupler 22
detects passage of the rotating disk 13 through the slit 15, and the reset photocoupler 23 detects the passage of the rotating disk 13 through the slit 15.
The passage of the reference hole 21 is detected. Note that even if the reference hole 21 passes through the reset photocoupler 23 with respect to the through hole 16 as shown by the dashed line in FIG. It is becoming possible to detect it.

Now, when the driving shaft 1 is rotated by a motor or the like and the driven shaft 10 is rotated with no load,
Due to the elastic force of the transmission spring 12, the shielding plate 17 is slightly angularly displaced in the counter-rotational direction with respect to the rotating disk 13, and one end edge 19a of the shielding portion 19 and the leading slit 15a of the rotating disk 13 are further separated ( In this example, after 8 slits), the balance is maintained,
It is rotated at the same rotational speed as the disk 13 without causing any relative angular displacement. Therefore, in this state, the angular displacement detection photocoupler 22 is
Each time it rotates, it detects the passage of 38 (=30+8) slits 15, and outputs 38 output signals (hereinafter referred to as pulse signals) SG1 equal to the number of slits 15 passed.

Next, when a load torque is applied to the driven shaft 10, the shielding plate 17 is angularly displaced relative to the rotating disk 13 in the counter-rotational direction in proportion to the magnitude of the torque, so that The slit 15 is newly exposed from the slit shielding portion 19 of the shielding plate 17 by the amount of displacement [α]. Therefore, the angular displacement detection photocoupler 22 detects the passage of the slits 15 of the number (=38+α) which is the sum of the increased amount [α] every time the rotating disk 13 makes one rotation, and calculates the number of passages of the slits 15. (=38+α) pulse signals SG1 are output.

On the other hand, in the reset photocoupler 23, since the reference hole 21 is also displaced with the displacement of the shielding plate 17,
The angular displacement detection photocoupler 22 detects passage of the reference hole 21 before the passage of the slit 15 starts and outputs a reset pulse signal SG2. Therefore, the resetting photocoupler 23 closes the slit 15 for each rotation of the angular displacement detection photocoupler 22.
A reset pulse signal is always output before the passage of the signal is detected.

Next, a device for detecting abnormal load torque by measuring the load torque of the driven shaft 10 based on the pulse signal SG1 output from the angular displacement detection photocoupler 22 will be described with reference to FIG.

The counter circuit 25 is an addition counter and receives a pulse signal from the angular displacement detection photocoupler 22.
Each time SG1 is input, the number is added and counted, and the counted contents are output to the next stage comparator 26, and when the reset pulse signal SG2 from the reset photocoupler 23 is input,
The counting contents are cleared. Therefore, the counter circuit 25 generates a pulse signal every time the shielding plate 17, that is, the driven shaft 10 rotates once.
Counts SG1 and sends the counted contents to comparator 26
Output to. That is, the total number of pulse signals SG1 counted by the counter circuit 25 for each rotation of the driven shaft 10 means the load torque value [Tx] for each rotation of the driven shaft 10, and the load torque value [Tx ] will be input to the comparator 26.

The abnormal value setter 27 sets the maximum allowable load torque value [Tmax] of the load torque applied to the driven shaft 10, and the comparator 26 converts the maximum allowable load torque value [Tmax] to the counter circuit 25. The comparator 26 encodes the code so that it can be compared and determined with the load torque value [Tx] input from the comparator 26.
Output to.

The comparator 26 compares and determines the load torque value [Tx] output from the counter circuit 25 and the abnormal value setter 27 with the maximum allowable load torque value [Tmax], and determines whether the load torque value [Tx]
When the value matches the maximum allowable load torque value [Tmax], an abnormality signal is output to the abnormality display device 28. The abnormality display device 28 is composed of an indicator lamp or the like, and lights up in response to the abnormality signal to notify that an abnormal load torque is being applied to the driven shaft 10.

Therefore, the load torque of the driven shaft 10 can be accurately detected by the total number of pulse signals SG1 of the angular displacement detection photocoupler 22 output every time the driven shaft 10 rotates once.

In this case, the angular displacement detection photocoupler 22 detects passage of the last slit 15 not shielded by the slit shielding part 19 of the shielding plate 17, and finishes the angular displacement detection at that time.
After a predetermined period of time has elapsed (the rotary disk 13 has rotated a predetermined amount), the leading slit 15a having a large transparent area is detected first, and the next angular displacement detection is started. The amount of light received by the light-receiving element of the photocoupler 22 becomes extremely large as it passes through the leading slit 15a, and the photocoupler 22 with poor rise characteristics
Even if the pulse signal SG1 is at a level higher than the predetermined level Vs necessary for causing the counter circuit 25 to perform a counting operation, as shown by the broken line in FIG. The subsequent passage through each slit 15 can be reliably detected. Therefore, even if the rotating disk 13, ie, the driving shaft 1, rotates at a very high speed, the counter circuit 25 can reliably perform a counting operation and accurately count the total number of pulse signals SG1.

Moreover, the slits 15 of the rotating disk 13 are formed after forming the slits 15 from the slit 15 next to the first slit 15a to the 71st slit at regular intervals.
The slits 15 from the 87th slit to the 87th slit are formed so that the distance between their rotational direction side edges 15f gradually becomes wider exponentially toward the counterrotation direction, so that the slit 15 has a large width that can tolerate some error in the load torque. Accuracy can be freely selected when detecting a load torque and detecting a small load torque that requires a small error in the load torque. Moreover, since the 71st to 87th slits 15 are formed so that the through-hole area becomes larger in sequence, even when the rotational speed is extremely high, these slits 15 with large through-through areas can be used to connect the photocoupler 2.
2, it is reliably detected.

In this embodiment, the abnormality signal from the comparator 26 is output to the abnormality display device 28, but this abnormality signal is used to stop a driving means such as a motor driving the driving shaft 1, for example. It may also be a control signal. Further, the abnormal value setting device 27
The minimum allowable load torque value can be set instead of the maximum allowable load torque value set in , and the comparator 26 is set to the minimum allowable load torque value as the load torque value [Tx] decreases from a constant state. If the abnormality signal is output when the load is reached, it becomes possible to detect that the driven shaft 10 has become lightly loaded.

Furthermore, the count contents from the counter circuit 25 are outputted to the arithmetic control circuit 30, and based on the count contents, an increase in the amount of load torque applied to the driven shaft 10 from the no-load state is calculated. The display device 31 may display fluctuations in the load torque for each rotation or for every predetermined number of rotations.

Alternatively, the shielding plate 17 may be attached to the driving shaft 1 and the rotating disk 13 may be attached to the driven shaft 8.
In addition, in this embodiment, the rotating disk 13 has a slit 1.
5 and a reference hole 21 in the shielding plate 17.
However, both plates 13 and 17 may be made transparent and black stickers may be pasted at locations corresponding to the slit 15, the reference hole 21, etc., and the stickers may be detected.

Furthermore, in the embodiment, the pulse signal SG1
The relative angular displacement of the driving shaft 1 and the driven shaft 8 based on the total number of , that is, the amount of torsion is taken as the load torque value [Tx], but this may be displayed as it is on the display device as the amount of torsion.

Further, instead of the transmission spring, a rotation transmission mechanism using a torsion bar or magnetic force may be used.

Effects As detailed above, according to the present invention, it is possible to accurately and reliably detect the amount of twist and the variation in the amount of twist from time to time in a wide range of conditions from low rotation speeds to high rotation speeds. This has the effect that it can be used in torque detection devices and the like.

[Brief explanation of the drawing]

Fig. 1 is an output waveform diagram of the output signal output from the angular displacement detection device, and Fig. 2 is a partial longitudinal cross-section showing how the rotating disk and shield plate are attached to the driving shaft and driven shaft, embodying the present invention. Figure 3 is a front view of the rotating disk, Figure 4 is a front view of the shielding plate, and Figure 5 is a front view of the rotating disk.
The figure is a side view showing the arrangement of photocouplers with respect to the rotating disk and the shielding plate, and FIG. 6 is an electric block circuit diagram. Driving shaft...1, driven shaft...8, driven shaft...10, transmission spring...12, rotating disk...13, slit...15, 15a, shielding plate...17, slit shielding part...19, photocoupler for angular displacement detection... 22, Reset photocoupler...23, Counter circuit...25, Comparator...26, Abnormal value setting device...27, Abnormality display device...28, Reference position as one point...P.

Claims (1)

[Claims] 1. A driving shaft 1 that is rotationally driven in one direction, a driven shaft 8 disposed on the same axis as the driving shaft 1, and a rotation of the driving shaft 1 between the shafts 1 and 8. It is arranged so as to transmit the motion to the driven shaft 8 side, and the relative angle between the driving shaft 1 and the driven shaft 8 is less than 360° depending on the magnitude of the load on the driven shaft 8 side. Rotary motion transmission means 1 for causing displacement
2, attached to either the driving shaft 1 or the driven shaft 8, and extending over a range larger than the angular displacement at the maximum load applied to the transmission means 12 on the same circumference centered on the axis; a rotating disk 13 on which a large number of detected portions 15 for angular displacement detection are formed at predetermined intervals from a predetermined point P in the counter-rotational direction of both axes; When the driving shaft 1 rotates, the detected part 15 for detecting angular displacement is disposed opposite to the
a detecting body 22 that sequentially detects from the one point P; and a detecting body 22 that is attached to the other of the driving shaft 1 and the driven shaft 8, and detects the detected part 15 for detecting the angular displacement of the rotating disk 13 by the detecting body 22. A shielding portion 19 is formed in a range less than 360° around the axis in order to shield the detected portion 15 so as to disable the detection portion 15 for angular displacement detection. One end edge 1 of the shielding part 19 facing the side formed at a predetermined distance from the point P
9a is relatively approached and separated from the one point P according to the angular displacement of the driving shaft 1 and the driven shaft 8,
The detection object 22 is connected to the shielding part 1 from the one point P.
a shielding plate 17 for shielding and opening the angular displacement detection detection portion 15 such that the number of the angular displacement detection detection portion 15 that can be detected increases or decreases up to the one end edge 19a of the angular displacement detection detection portion 15; When the detection body 22 detects the angular displacement detection portion 15 between the one point P and the one end edge 19a of the shielding plate 17, it is counted based on the generation of the detection signal, It is equipped with control devices 21, 23, and 25 that calculate the angular displacement between the driving shaft 1 and the driven shaft 8 based on the counting results, and is configured to detect the amount of twist between the driving shaft 1 and the driven shaft 8. In the torsion detection device, the area of at least one detected portion 15a on the one P side of the detected portions 15 for detecting angular displacement is formed to be larger than the area of other adjacent detected portions 15. A torsion detection device characterized by the following. 2 Detected part 1 for detecting angular displacement of the rotating disk 13
Reference numeral 5 denotes a transparent slit, and the detection body 22
The torsion detection device according to claim 1, wherein is a light receiving element.