JPH03205526A - Detecting device for rotational torque - Google Patents

Abstract

PURPOSE:To house a device in the limited space without making it to large size by converting to an electrical signal and taking out the displacement to the axial direction which is converted by a displacement direction converter in accordance with the displacement in the rotational direction between a driving shaft and driven shaft. CONSTITUTION:In the torque detecting device, when a rotational force is exerted to the driving shaft 1 in the direction of the arrow A, the length of a cylindrical member 9 is shorten by contraction of a slit 17 and the length of a cylindrical member 15 is lengthened by expansion of a slit 18. A bobbin 16 is displaced in accordance with the above and the inductance of a resonance circuit R becomes large, which is detected by a detecting circuit S as a decrease in the frequency and also converted to a voltage signal by a V/f converter 26. The frequency becomes large in accordance with the increase of a rotational angle of driving shaft 1 in the direction of the arrow A. This detecting device for rotational torque is mounted with the cylindrical parts 9, 15 having the outside diameters almost equal to those of the driving shaft 1 and driven shaft 2, and further the bobbin 16 having the diameter almost equal to those of the members 9, 15 is interposed between both members. Consequently, the entire device is not remarkably protruded from the outside diameters of both shafts 1, 2 and can be housed in the limited space.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a rotational torque detection device.

[Conventional technology] There are the following rotary torque sensors used in power steering devices of industrial vehicles.

That is, as shown in FIG. 9, the drive shaft 41 and the driven shaft 42
are connected by an elastic body 43, and the elastic body 43 is sandwiched between the drive shaft 41 and the driven shaft 42 due to the torque applied to the drive shaft 41, causing a shift in the rotational direction. Then, the metal core 44 fixed to the driven shaft 42 side is displaced relative to the detection coil 46 drawn from the solenoid coil 45 wound on the drive shaft 41, and the solenoid coil 45 and capacitor 47 This changes the inductance of the constructed resonant circuit. An input coil 48 and an output coil 49 wound around a magnetic core are arranged opposite to the solenoid coil 45, and the change in inductance is used as the oscillation frequency of an oscillation circuit constituted by the input coil 48, output coil 49, and resonant circuit. It is extracted and converted into a voltage signal.

[Problems to be Solved by the Invention] However, as shown in FIG. It was established in

For this reason, the sensor as a whole becomes large, making it unsuitable for use around a steering shaft where mounting space is limited.

This invention was made to solve the above-mentioned problems, and its purpose is to provide a rotational torque detection device that can be stored even in a limited space without increasing the size of the entire sensor. There is a particular thing.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a device that is interposed between a driving shaft and a driven shaft and detects the rotational torque applied to both shafts. Displacement direction converting means for elastically displacing in the axial direction in accordance with the displacement, and converting and extracting means for converting the axial displacement converted by the displacement direction converting means into an electric signal and extracting it. This is the summary.

[Operation] Displacement in the rotational direction between the drive shaft and the driven wheel is converted into a displacement in the axial direction by the displacement direction conversion means, and the displacement in the axial direction converted by the displacement direction conversion means is electrically converted by the conversion and extraction means. It is converted into a signal and extracted.

[Example] Hereinafter, a first example of the present invention will be described in detail with reference to FIGS. 1 to 5.

In FIG. 1, a drive shaft 1 and a driven shaft 2 are arranged opposite to each other on the left and right, and a drive-side mounting hole 3 and a driven-side mounting hole 4 are formed in the opposing end surfaces of the drive shaft 1 and the driven shaft 2 in the axial direction, respectively. It is perforated. Each end of the torsion bar 5 is inserted into the mounting holes 3 and 4, and a stopper pin 6 is press-fitted in the diameter direction of each shaft 1 and 2 so as to intersect with the mounting holes 3 and 4. , 7 hold the seation bar 5 against both shafts 1 and 2 so as not to be detachable.

As shown in FIG. 2, a cylindrical member 9 made of an elastic material such as rubber is attached to a flange portion 8 formed on the outer peripheral surface of the drive shaft 1 by a fitting ring IO. And drive shaft 1
A copper ring l2 is fixed on the circumferential surface of the protrusion 1l that extends in the entire circumferential direction from the inner end side of the flange part 8, and is driven toward the driven shaft 2 side than the extension range of the cylindrical member 9. The inner end of the shaft l protrudes.

On the other hand, the flange portion 13 formed at the inner end of the driven shaft 2 also has 3
Step fitting ring 1 4 a + 1 4 b , 1
A cylindrical member 15 made of an elastic material is attached via the cylindrical member 4c, and within the cylindrical member 15, the inner end of the drive shaft l faces the inner surface of the flange portion l3 of the driven shaft 2 with a gap in between. The cylindrical member 15 is connected to the cylindrical member 9 on the drive shaft 1 side by a bobbin 16.

In the cylindrical member 9 on the driving shaft l side, a large number of oblique slits l7 are arranged along the entire circumferential direction so that the height becomes lower toward the driven shaft 2 side, and the driven shaft member 9 is line-symmetrical with this. The same number of slits 18 are formed in the cylindrical member l5 on the shaft 2 side and are inclined at the same angle in opposite directions. Then, when a rotational force is applied to the drive shaft l in the direction of arrow A, the cylindrical member 9 is moved through the slit 1.
The length of the cylindrical member 15 becomes shorter due to the contraction of the cylindrical member 7, and the length of the cylindrical member 15 becomes longer due to the expansion of the slit 18. Conversely, when a rotational force acts on the drive shaft l in the direction of arrow B, the cylindrical member 9 closes in the slit l.
The cylindrical member I5 becomes longer due to the expansion of the slit 7, and becomes shorter due to the contraction of the slit 18.

As shown in FIG. 1, the hobbin 16 has a winding groove 19 extending in the entire circumferential direction, and a solenoid coil 20 wound around the winding groove l9 has a capacitor 21.
are connected in series. The copper ring l2 is always in a position close to the solenoid coil 20,
A resonant circuit R is constituted by a solenoid coil 20 in sliding contact with the inner surface of the bobbin 16 and a capacitor 21 connected to the solenoid coil 20 on the bobbin 16 in FIG. Then, due to the expansion and contraction of the cylindrical members 9 and l5 described above, the position of the bobbin changes, and the solenoid coil 2
When 0 is displaced, the inductance of the resonant circuit R is increased or decreased.

At a position facing the solenoid coil 20, an output coil 22 and an input coil 23 of a detection circuit S, which will be described later, are placed with a gap in between.As shown in FIG. Excite. And solenoid coil 20 and copper ring l2
The inductance of the resonant circuit R changes according to the relative displacement between the resonant circuit R and the resonant circuit R.

This is detected by the input coil 23 on the detection circuit S side, and a voltage with a frequency corresponding to the changing inductance is extracted as a pulse frequency via the amplifier 24 and the positive feedback circuit 25, and the frequency is transferred to the f/V converter 26. is converted into a voltage, and the drive source is controlled based on the voltage value.

Now, in the torque detection device configured as described above, when a rotational force acts on the drive shaft l in the direction of arrow A, the length of the cylindrical member 9 decreases due to contraction of the slit 17, as shown in FIG. The cylindrical member 15 becomes longer due to the expansion of the slit 18. Along with this, the bobbin 16 is displaced, the solenoid coil 20 approaches the copper ring l2, and the resonant circuit R
inductance increases. This is detected by the detection circuit S as a decrease in frequency, and converted into a voltage signal by the V/f converter 26.

In addition, as shown in FIG. 5, the above-mentioned frequency is
increases as the rotation angle in the direction of arrow A increases.

In this rotational torque detection device, cylindrical members 9 and 15 having approximately the same outer diameter as the driving shaft 1 and driven shaft 2 are mounted, and a bobbin 16 having approximately the same diameter as the cylindrical members 9 and 15 is attached to both the driving shaft 1 and the driven shaft 2. 15, so that the entire device does not protrude noticeably from the outer diameter of both shafts 1 and 2. Therefore, the device can be downsized and can be accommodated within a limited space.

Next, a second embodiment of the invention will be described with reference to FIGS. 6-8.

In these embodiments, a cover 10 made of an inelastic material is provided to cover the cylindrical member 9 as shown in FIG. The solenoid coil 20 is inserted into the member 9, and the copper ring l2 and the solenoid coil 20 are displaced relative to each other by deformation of the cylindrical member 9.

FIG. 7 also shows that the displacement direction converting means is the cylindrical member 9,
15, a resin ring 27 is used. Each resin ring 27 is connected to a pair of diagonal body arms 30 in front and rear of an outer shaft mounting part 28 and an inner bobbin mounting part 29.
It is integrally molded from flexible resin so as to be connected by. Then, the bobbin mounting portion 29 of both resin rings 27
are connected by bobbin l6, and both resin rings 27
A driving shaft 1 and a driven shaft 2 having the same structure as in the first embodiment are fitted into a bobbin 16.

Even in this structure, one resin ring 27 is contracted by the bending of the arm 29 due to the rotational torque applied to the drive shaft 1, while the other resin ring 27 is contracted by the bending of the arm 29 in the opposite direction. The axial position of l6 changes. As a result, the solenoid coil 20 and the copper ring l
Based on the deviation in the relative position with respect to the detection circuit S, a change in the inductance of the resonant circuit R, that is, a change in the frequency from the detection circuit S is converted into a voltage and taken out.

Furthermore, FIG. 8 shows another example of this embodiment. That is, each resin ring 27 has an outer shaft mounting part 28 and an inner bobbin mounting part 29 formed separately, and these mounting parts 28 .
29 are connected at the front and back by metal leaf springs 31, and the shaft mounting portion 28 of both resin rings 27 and the inner bobbin mounting portion 2 are connected.
A drive shaft 1 and a driven shaft 2 are fitted into a bobbin 9 and a bobbin 16.

Even with this structure, the effect is not inferior in any way compared to the above two structures.

[Effects of the Invention] As described in detail above, the present invention exhibits an excellent effect in that the sensor as a whole can be stored in a limited space without increasing its size.

[Brief explanation of drawings]

Figures 1 to 5 show a first embodiment of the present invention, in which Figure 1 is a side view showing a rotating torque detection device together with a drive shaft and a driven shaft, and Figure 2 shows its main parts. Partially cutaway side view, Figure 3 is a partially cutaway side view showing the state in which the bobbin is displaced due to rotational torque being applied to the drive shaft, Figure 4 is a circuit diagram showing the electrical configuration, and Figure 5 is the rotation angle. A diagram showing the relationship between the difference and the frequency, FIG. 6 is a side view showing the second embodiment, FIGS. 7 and 8 are side views each showing another example of the second embodiment, and FIG. 9 is a side view showing the second embodiment. FIG. 10, which is a circuit diagram showing a conventional example, is a perspective view also showing a conventional example.

Claims (1)

[Claims] 1. In a device that is interposed between a driving shaft and a driven shaft and detects rotational torque applied to both shafts, a displacement direction conversion device that elastically displaces in the axial direction in response to displacement in the rotational direction between the two shafts. A rotational torque detection device comprising: means for converting the displacement in the axial direction converted by the displacement direction converting means into an electric signal and extracting the electric signal.