JPS5845529A - Measuring device for torque of rotating shaft - Google Patents

Abstract

PURPOSE:To make a device simple and small in size by converting torque to a displacement, measuring said displacement and calculating the torque. CONSTITUTION:When torque is transmitted between a driving shaft 1 and a driven shaft 4, torsion is generated between both shafts, and the circumferential displacement of a bracket 9 with respect to a cam 8, hence a rod 10, attains the rate proportional to the torsion. The rod 10 of which the preceding end is held in press contact with the cam 8 at all times, hence, an annular plate 12 mounted to the same is displaced axially by the cam 8. Thus the torque of the rotating shaft is determined by measuring the axial displacement of the plate 12.

Description

[Detailed description of the invention] The present invention relates to a torque detection device for a rotating shaft.

As a conventional device for detecting the torque of a rotating shaft, there is one that detects strain due to shaft torsion using an electric resistance wire strain gauge, and calculates torque from the detected strain. However, in this type of device, the output of the strain gauge must be extracted off-axis via a slip ring. However, since the slip ring uses mercury, it has drawbacks in terms of safety and is expensive. In addition, the strain gauge itself has a drawback of poor durability and environmental resistance.

In addition to the strain gauge-based detection devices mentioned above, there are detection devices based on the inductance change method and detection devices based on the magnetostriction method, but they all use special materials and have complex structures. It's expensive.

Furthermore, since the device is large, it is difficult to mount it on the rotating shaft of a general rotating machine.

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide a torque detection device for a rotating shaft that has excellent durability and environmental resistance, can be constructed in a small size, and can be provided at low cost.

In the present invention, the above object is achieved by converting torque into displacement and measuring this displacement to calculate torque.

The invention will now be described in detail with reference to the drawings. Figure 1 A%
B is a diagram showing the principle of the present invention. In these diagrams, a shallow cylindrical cup 3 having fan-shaped recesses 2, 2 located at both diameter ends on the inner peripheral surface is concentrically attached to the shaft end of the drive shaft 1. A radial protrusion 5.5 is fixed to the shaft end of the driven shaft 4 facing the drive shaft IK, which engages with the inner periphery of the cup 3, is located at both diametrical ends of the curved surface, and projects into the fan-shaped recess 22. A disk 6 having a diameter is fixed concentrically. In the fan-shaped recesses 2, 2, there are protrusions 5, respectively.
, 5 are arranged with coil springs 7 on both sides.

In the above configuration, when the drive shaft 1 is rotated, the rear side wall of the fan-shaped recess 2 in the rotation direction of the drive shaft compresses the spring 7 between the side wall and the protrusion 5, and a torque is generated via the protrusion 5 and the disk 6. is transmitted to the driven shaft 4, causing it to rotate. Here, when the number of springs involved in torque transmission is nl, their spring constant is 1, the center radius of the spring is 1, the transmitted torque is To, the force acting on one spring is F, and F=TO/ Cn, R8) ・・・・・・・・・・・・
...---(1), and the amount of spring deformation δ at that time is
0 is δo=TO/(n, R3, K)... River... Nao2). The deformation of this spring is disk 6 and cup 3.
The twist angle θ is θ; δo/Rs = To/(n #R82-K)-
-・curve (g), and the circumferential relative displacement δ at a certain radius position is δ=R−θ=(R−To)/(n*R52−K
)...This becomes song (4).

Therefore, by measuring the circumferential relative displacement δ, the acting torque To can be calculated from equation (4).

However, in reality, it is difficult to directly measure the circumferential relative displacement δ. Therefore, in the present invention, the circumferential relative displacement is converted into an axial relative displacement, and the torque To is determined from this. ing.

FIG. 2, in which the same parts as in FIG. 1 are given the same reference numerals, shows an embodiment of the present invention. In this figure, it goes without saying that the cup 3 and the disk 6 are provided with a torque transmission mechanism having the same structure as that shown in FIGS. 1A and 1B. Therefore, in the present invention, a spiral with a helical angle α is located at a position where the fan-shaped recess 2 is not present on the end face of the cup 3 on the driven shaft 4 side, for example, at both ends of the diameter perpendicular to the diameter passing through the center of the four parts 2. The cams 8 forming a part are mounted concentrically. On the other hand, brackets 9 are provided on the circumferential surface of the portion of the circumferential surface of the disc 6 outside the cup 3, located at both ends of the diameter perpendicular to the diameter passing through the protrusion 5. A rod 10 is engaged so as to be slidable in parallel directions. A rolling ball 11 is provided at the end of the rod 10 on the cup 3 side, and an annular plate 12 concentrically surrounding the driven shaft 4 is attached to the other end. Further, a spring force is applied to the rod 10 by a spring 13 in a direction to press the rolling ball 11 against the cam 8.

In the above configuration, when no torque is applied, the protrusion 5 of the disc 6 is located at the circumferential center of the sector-shaped recess 2 due to the balance between the springs 7 on both sides, and therefore the rod 10 is also located at the circumferential center of the cam 80. .

Now drive shaft 1. It is assumed that torque 〉 is transmitted between the driven shafts 4 and that a twist of θ occurs between the two shafts. If the center radius of the cam 8 is R, the circumferential relative displacement δ' of the placket 9 and therefore the rod 10 with respect to the cam 8 is δ'=R'θ ・・・・・・・・・・・・・・・・・・・
(5) The rod 10 whose tip is always in pressure contact with the cam 8, and therefore the annular plate 12 attached to the rod, is moved in the axial direction by the cam 8. is displaced. The amount of displacement δ7 is determined by formula (4) as follows: δ'z = δ'tanα = (R' ・To)/(n@Rs2*K) tan
α......(6).

Therefore, by measuring the axial displacement of the annular plate 12, the torque To can be determined according to equation (6).

In this embodiment and the explanation of the principle described above, the springs 7 are arranged on both sides of the protrusion 5 in consideration of the fact that the shaft rotates in both forward and reverse directions. Further, the positional relationship with the rod 1 (l cam 8) is determined based on the same considerations.If the shaft rotates only in one direction, the spring 7 It is only necessary to arrange the rod 10 between the rod 10 and the rear side wall, and the rod 10 does not need to be located at the center of the cam 8 in the circumferential direction.

3A and 3B, in which the same parts as in FIGS. 1 and 2 are denoted by the same reference numerals, show another embodiment of the present invention. In this embodiment, radial pins 14 are installed on the outer circumferential surface of the cup at both diametrical ends thereof, and on the outer circumferential surface of the portion of the disc 6 outside the cup 3, pins 14 are installed at both diametrical ends. A bracket 15 having a support surface 15a forming a part of an extension of the outer peripheral surface of the cup 3 is attached at a position facing the pin 14 when the inter-shaft torque is not transmitted. The support surface 15aK of this bracket 15 is
A radial bin 16 is installed at a position opposite to 4.

An L-shaped bell crank 17 is rotatably attached to the pin 16 at its bent portion, with a notch 17a at the tip of the monopod engaging the pin 14. Further, the tip of the other leg of the bell crank 17 is pivotally attached to the circumferential surface of the annular plate 12 by a pin 18.

Assume that a twist of θ occurs between both axes in the same manner as in the above embodiment. Here, if the rotation radius of the center of the bell crank 17 is R", then the circumferential relative displacement δ" between the pin 16 (pivot point) and the engagement point with respect to the pin 14 is.

δ"=R"・θ ・・・・・・・・・・・・・・・・・・
...... (7), and let the length of the bell crank from the pin 16 (pivot point) to the engagement point be tl, and the distance between the pins 16 and 18 be t2. For example, due to the rotation of the bell crank 17 caused by the above-mentioned relative displacement in the circumferential direction, an axial displacement is applied to the annular plate 12. The axial displacement δ turtle is δ1=δ"×t2/l□ = (R"・t2・To)/(n-R82・K-tl)・
...(8). Therefore, similar to the above embodiment,
The axial displacement of the annular plate 12 is measured and the torque T is determined according to equation (8).

can be calculated.

Parts that are the same as those in Figures 1 to 3 are designated by the same reference numerals.
, B, C, and D show other embodiments of the present invention. In this embodiment, a shallow cylindrical cup 23 is fixed concentrically to the shaft end of the drive shaft 1, and a disk 26 with a diameter considerably smaller than the inner diameter of the cup 23 is mounted to the shaft end of the driven shaft 4. are fixed concentrically.

Thus, the inner periphery of the cup 23 and the outer periphery of the disk 26 are connected by two leaf springs 20 arranged on one diameter, and a leaf spring 20 on the circumferential surface of the disk 26 is located at the intermediate position of the leaf spring 20 on one diameter. , cup 2
Two brackets 21 are attached that extend to the vicinity of the inner periphery. A notch 21a is provided in the cup 23 side surface near the tip of the bracket 21 to make the tip portion thin. Further, a cam 28 similar to the cam 8 shown in FIG. 2 is provided on the inner end surface of the cup 23 at a position facing the tip end of the bracket 21 when torque is not transmitted. The tip of the bracket 21 has a second
A rod 10 similar to the rod 10 shown is provided. An annular plate 12 is attached to the rod 10.

In this embodiment, the torque of the drive shaft 1 is controlled by the leaf spring 20.
At this time, the leaf spring 20 is bent, causing a torsion of θ between the two shafts. Due to the twisting of the shaft, an axial displacement is applied to the annular plate 12 in the same manner as described above, and by measuring this displacement, the torque To can be calculated.

The axial displacement of the annular plate 12 in each of the above embodiments can be measured as shown in FIG. 5A1B. That is, what is shown in FIG. 5A is a measurement rod 3o having a wheel 30a at one end, and a measuring rod 3o having a wheel 30a at one end.
The measurement rod 30 is provided with a spring force in pressure contact with the annular plate 12 in addition to the spring 31. In this way, since the measuring rod 3o slides as the annular plate 12 is displaced in the axial direction, this movement can be immediately displayed as torque on the dial gauge in an analog manner. Further, by converting the movement of the measuring port and the rad 30 into a non-staining signal such as a differential transformer, the torque can be determined analogously or digitally by signal processing. FIG. 5B shows another measurement method, in which a self-inductance variable non-contact displacement meter 32 is provided opposite the annular plate 12. When this is done, torque can be determined in a non-contact manner.

As is clear from the above, according to the present invention, it is possible to configure a rotating shaft torque measuring device without increasing the size. Furthermore, since the device of the present invention does not use a strain gauge, it has excellent durability and environmental resistance, and since it does not use any special materials, it is not expensive. Sixth, the device of the present invention can be used from a rotational speed of O. moreover,
By appropriately selecting the rigidity and number of elastic members such as coil springs and plate springs that relate the drive shaft and driven shaft, the detection allowable torque can be arbitrarily set. Furthermore, since there is no need to extract electrical signals from the rotating shaft, there is no need to use a slip ring, which poses problems in terms of safety, stability, cost, etc. Incidentally, since the axial displacement measured to determine the torque has a considerable magnitude, it also has the advantage of being relatively unaffected by disturbances. Further, since the axial displacement can be easily converted into an electric signal using a differential transformer, a non-contact displacement meter, etc., the shift torque can be calculated by signal processing.

Note that the present invention is not limited to the above embodiments. For example, the driven shaft may be driven from the illustrated driven shaft side, and the number of rods, bell cranks, etc. that convert circumferential displacement into axial displacement is not limited to the two illustrated.

[Brief explanation of drawings]

Figure 1A%B//i Figure 2A is a front view of the first embodiment of the present invention, Figure 2B is a main part thereof. 3A is a front view of the second embodiment of the present invention, FIG. 3B is a longitudinal sectional view of the main part thereof, and FIG. Figure, Figure B
5A is a cross-sectional view of the same, FIG. 5C is a partially cutaway front view, and FIG. Figure B is a similar view of the second modification. l... Drive shaft, 3.23... Cup, 4...
・Driven shaft, 5...Protrusion, 6.26...
Disc plate, 7... Coil spring, 8. 28...
・Cam, 10...rod, 12...annular plate,
21... Leaf spring. Application agent Patent attorney Kikuchi Fifth Department 1 (A) #12 (A) (B) Figure (B) No. 3111 θ (Q) (Z)) #5
figure

Claims (1)

[Claims] (1) The driven shaft and the driving shaft are connected by an elastic member having elasticity in the circumferential direction of each shaft, and a conversion means is provided to convert the torsion between the shafts during torque transmission into axial displacement, and this conversion A torque measuring device for a rotating shaft, characterized in that the means includes an annular plate that concentrically surrounds the driven shaft or the driving shaft.