JPH01140035A - Torque detector - Google Patents

Abstract

PURPOSE:To attain high reliability by providing a cylindrical coil core being movable in the axial direction, a linear core extending over the opposite ends of the cylindrical coil core, and separate windings being connected electromagnetically to the two cores respectively and slidable, so that a power or the like can be transmitted. CONSTITUTION:A cylindrical coil core 23 connected to a linear core 24 at the opposite ends is disposed on the end part side of a moving body 21 made slidable on a threaded shaft 20 of an input shaft 2, and one end of the core 24 is fixed to a supporting body 31. Moreover, a winding 25 on the power supply side is provided on the core 24, while a winding 26 on the load side connected to a light-emitting element 5 is provided on the core 23, and an alternating current is supplied to the winding 25 to make the light-emitting element 5 emit a light through the winding 26. When the shaft 2 is rotated, a light-reflecting surface 7 is displaced, together with the light-emitting element, in relation to a light-reflecting surface 8, the respective reflected lights of the surfaces are projected to positions different in the circumferential direction of first and second photosensing elements 11 and 12. Incident lights on the photosensing elements 11 and 12 are subjected to photoelectric conversion respectively and then to phase comparison, and thereby the torque of the input shaft 2 in relation to an output shaft 3 is detected. Since no contact part is interposed, accordingly, high reliability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a torque detection device, and is particularly suitable for application to an electric power steering device of an automobile.

The present invention provides a torque detecting device with a high level of performance.

[Conventional technology]

2. Description of the Related Art Electric power steering devices are being developed that assist the power to operate the steering wheels of automobiles. This has a structure that detects the torque applied to the steering wheels and rotates an electric motor provided in the steering mechanism according to the detected torque.

Torque sensors for detecting the torque applied to the steering wheel are known to use, for example, potentiometers or strain gauges, and the output signal of such a torque sensor is determined by the input signal to which the steering wheel is attached. It has a structure in which it is guided out via a slip ring provided on the shaft.

[Problem that the invention seeks to solve]

As mentioned above, the torque signal of the conventional torque sensor is derived through the slip ring, so frequent steering operations of the steering wheel gradually deteriorate the contact condition between the slip ring and the brush, which causes damage over a long period of time. There is a problem in that an accurate torque signal cannot be obtained and reliability is reduced.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a torque detection device that can derive the output signal of a torque sensor without intervening a contact part and has high reliability over a long period of time.

[Means for solving problems]

A torque detection device according to the present invention is a torque detection device for detecting torsion between an input shaft and an output shaft connected via a torsion bar, and the torque detection device surrounds the input shaft or the output shaft. A cylindrical coil core disposed to move in the axial direction as the shaft rotates, a linear core connected across both ends of the cylindrical coil core, and the cylindrical coil core and It is characterized by comprising windings that are electromagnetically coupled to each of the linear iron cores and are slidably wound individually.

[Effect]

When an electrical input is applied to one or the other of the windings of the cylindrical coil core and the linear core, which are wound while being electromagnetically coupled to each other, an electrical output is obtained from the other or one of the windings.

When the input shaft is rotated, the cylindrical coil core moves in the axial direction of the input and output shafts, and each winding moves along the cylindrical coil core and the linear core.

Thereby, current or signals can be transmitted to the rotating side without intervening a contact part.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 1 is a perspective view of a steering shaft portion to which a torque detection device according to the present invention is applied. An input shaft 2 serving as a steering shaft to which a steering wheel l is attached is connected via a torsion bar 4 to an output shaft 3 to which a pinion (not shown) of a steering mechanism is attached. On the outer peripheral surface of the input shaft 2 on the side facing the output shaft 3,
A light emitting part holder 6 is fixedly attached to the light emitting part 5 so that the light emitting part 5 can be positioned at a position separated from the outer peripheral surface by an appropriate length.

A light reflecting surface 7 that is flat and parallel to the axial direction is provided on the axis of the input shaft 2 where the light emitting section 5 is located and at a position separated from the light emitting section 5 by an appropriate length in the axial direction. Further, on the outer peripheral surface of the output shaft 3, a light reflecting surface 8 similar to the light reflecting surface 7 is provided at a position separated from the light emitting section 5 by a distance equal to the distance between the light emitting section 5 and the light reflecting surface 7. and light reflecting surfaces 7 and 8
This means that when no torque is acting on the input shaft 2, the light emitting section 5 is located on a straight line parallel to the input shaft 2. On the upper side of the inner peripheral surface of the cylindrical steering column 9 through which the input shaft 2 and the output shaft 3 are inserted, one end of a large number of optical fibers 10 is installed at positions on the inner peripheral surface equidistant from the upper edge of the steering column 9. First light receiving portions 11 are arranged side by side in the circumferential direction. Further, on the lower side of the inner circumferential surface of the steering column 9, one end of a large number of optical fibers 10 are placed in parallel in the circumferential direction at positions on the inner circumferential surface equidistant from the lower edge of the steering column 9. A second light receiving section 12 is provided. The base points for arranging one ends of these optical fibers 10 in parallel are set at the same position in the circumferential direction. The other ends of the optical fibers 10 and 10 forming the first and second light receiving sections 11 and 12 are sequentially connected to the linear image sensors 13 and 14 from the base point side of the optical fibers 10 arranged in parallel. The first pixel faces the first pixel. The light received by the second light receiving section 11.12 is made to enter the linear image sensor 13.14.

FIG. 2 is a cross-sectional view of the inside of the steering column through which the output shaft is inserted, and when no torque is acting on the input shaft 2, the light reflection surface 7 of the input shaft 2 and the light reflection of the output shaft 3 are shown. The surfaces 8 are the same plane, and the light emitted from the light emitting section 5 is reflected by both the light reflecting surfaces 7 and 8, and the reflected light is reflected in the circumferential direction of the first and second light receiving sections 11 and 12, as shown by broken lines. incident at the same position.

On the other hand, when torque is applied to the input shaft 2, the positions of the light reflecting surface 8 of the output shaft 3 and the light reflecting surface 7 of the input shaft 2 are displaced in the circumferential direction corresponding to the torsion of the torsion bar 4. , 1st
And the reflected light comes to be incident on different positions in the circumferential direction of the second light receiving sections 11 and 12.

FIGS. 3 and 4 are a cross-sectional view and a plan view showing a power feeding structure for feeding power to the light emitting section 5. FIG. steering column 9
A part of the inner input shaft 2 is a screw shaft 20 with a spiral groove 20a formed on the outer peripheral surface over a required length. This screw shaft 20 is provided with a rectangular parallelepiped-shaped moving body 21 that is inserted through the screw shaft 20 and can be moved in the axial direction. Arm portions 21c and 21c are protruded from both sides of the moving body 21, and a guide shaft 30.30 parallel to the screw shaft 20 is slidably inserted into these arm portions 21C921c. 21 is prevented from rotating. Furthermore, the screw shaft 20 is inserted into the screw hole 21a of the movable body 21 through which the screw shaft 20 is inserted.
A ball groove 21b of a required length is formed opposite to the spiral groove 20a, and a large number of balls 22 are disposed between the spiral groove 20a and the ball groove 21b. Therefore, screw shaft 2
0 is rotated, the movable body 21 moves smoothly in the axial direction of the screw shaft 20.

At one end of the movable body 21, a cylindrical coiled iron core 23, which is formed by winding a magnetic material made of silicon steel material with a required number of turns, has a diameter sufficiently larger than the diameter of the screw shaft 20, and is loosely attached to the screw shaft 20. It is fitted. This cylindrical coiled core 2
3 are connected to respective ends of a linear iron core 24 whose both ends are bent in the same direction in an L-shape, and the cylindrical coiled iron core 23 and the linear iron core 24 form a closed magnet. A road is formed. The cylindrical coiled iron core 23 is attached to the screw shaft 2
0 and spaced apart from the screw shaft 20, one end of the linear iron core 24 is fixedly attached to a support 31 fixed to one end of the movable body 21, and its supporting state is The mechanical strength of the linear core 24 is high for stability. A power source side winding 25 having a required number of turns connected to a power source (not shown) is slidably wound around the linear core 24 . Further, a load-side winding 26 connected to the light emitting section 5 with a required number of turns is slidably wound around the core portion of the cylindrical coiled core 23. When a steering operation is not performed, the power supply side winding 25 and the load side winding 26 are located approximately in the middle of the linear iron core 24 and the cylindrical coiled iron core 23 in their respective length directions. There is.

The lead wire 11 of the power supply side winding 25 is supported on the inner circumferential surface of the steering column 9 by appropriate means with a sufficient length. The lead wire 1z of the load side winding 26 is made of a slightly hard wire material, and the load side winding 26 is supported at a predetermined position radially away from the screw shaft 20, and the lead wire 1z is
A load side winding 26 is disposed so as to be supported in the middle of the lead wire support 27 on the outer surface of a lead wire support 27 which is externally fitted and fixed to the screw shaft 20 . Therefore, when the screw shaft 20 is rotated, the coiled iron core 23 and the straight iron core 24 integrated with the moving body 21 are rotated.
moves in the axial direction of the screw shaft 20, and the linear iron core 24 moves within the power supply side winding 25. On the other hand, due to the rotation of the screw shaft 20, the load-side winding 26 attached to the lead wire support 27 moves in the circumferential direction along the core portion of the cylindrical coiled iron core 26. Then, the power supply side winding 25 is connected to the power supply (
By connecting the AC), the linear iron core 24 and the cylindrical coiled iron core 23 are excited, and a voltage (alternating current) is induced in the load side winding 26 which is electromagnetically coupled to the cylindrical coiled iron core 23, and the connection is made to this. A current flows through the light emitting section 5, and the light emitting section 5 emits light.

Next, the torque detection operation of the torque detection device configured as described above will be explained with reference to FIGS. 1 to 3.

When a power source (alternating current), not shown, is connected to the power supply side winding vA25, the cylindrical coil iron core 23 and the linear iron core 24 are excited, a voltage (alternating current) is induced in the load side winding 26, and a current is applied to the light emitting part 5. The light emitting section 5 enters the light emitting state. As shown in FIG. 2, when no torque is acting on the input shaft 2, the light projected from the light emitting section 5 is reflected by the light reflecting surfaces 7.8 provided on the input and output shafts 2.3, respectively. 1st. Second light receiving section 1
1.12 and enters the pixels of the linear image sensor 13.14 corresponding to the respective positions.

When the input shaft 2 is rotated clockwise by the steering operation as shown by the solid line arrow in FIG. The respective reflected lights displaced in the clockwise direction relative to the light reflecting surface 8 and reflected by the light reflecting surfaces 7 and 8 are reflected by the first . Projections are made at different positions in the circumferential direction of the second light receiving section 11°12.

Further, the amount of displacement corresponds to the torque.

Therefore, in this way, the first. Second light receiving section 11°12
The amount of torsion of the input shaft 2 with respect to the output shaft 3, that is, the amount of twist of the input shaft 2 with respect to the output shaft 3, is determined by photoelectrically converting the incident light with the linear image sensor 13, 14, and comparing the phase of the photoelectrically converted signal with a phase comparator circuit (not shown). It is possible to detect the torque acting on the

Furthermore, when the input shaft 2 rotates in this way, the cylindrical coil core 23 moves along with the moving body 21 in the axial direction of the input shaft 2, so that the linear core 24 moves inside the power supply side winding 25. Moves smoothly and also has a cylindrical coil core 2
The iron core portion of No. 3 moves smoothly within the load side winding 26. Even if the human power shaft 2 is rotated, the power supply side and load side windings 2
5 and 26, a linear core 24, and a cylindrical coil core 23.
No change occurs in the electromagnetic coupling state with the Therefore, from the power supply side winding 25 on the fixed side to the load side winding 26 on the rotating side.
In contrast, it is possible to stably supply power without intervening contact parts.

In this embodiment, the power supply side winding 25 is connected to the load side winding 2.
6 has been described, for example, a torque signal detected by a torque sensor provided on the rotation side can be inputted to the load side winding 26, and the torque signal can be obtained by the power supply side winding 25. In that case, if the torque signal is weak, by increasing the number of turns of the power supply side winding 25, the induced voltage in the power supply side winding 25 can be increased and the torque signal can be accurately obtained.

Therefore, the problem of not being able to stably obtain a torque signal due to contact failure caused by a contact portion such as a slip ring, for example, is resolved.

〔Effect of the invention〕

As described in detail above, according to the present invention, power or signals can be transmitted between the rotating side and the stationary side without intervening a contact part. Therefore, torque can be detected stably even after long-term use, and a highly reliable torque detection device can be provided.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the steering wheel portion to which the torque detection device according to the present invention is applied, Fig. 2 is a sectional view of the inside of the steering column through which the person and the output shaft are inserted, and Figs. 3 and 4 are the light emitting section. FIG. 3 is a cross-sectional view and a top view showing a power supply connection structure for supplying current to the device. 2... Input shaft 3... Output shaft 4... Torsion bar 5... Light emitting part 7.8... Light reflecting surface 9...
Steering column 11... first light receiving section 12.
...Second light receiving section 21...Moving body 23...Cylindrical coil core 24...Straight core 25...Power supply side winding 26...Load side winding 27...Lead wire Support patent Applicant Koyo Seiko Co., Ltd. Agent Patent attorney Noboru Kono % 1 concave 42 figs. 3 mouth 514 concave

Claims (1)

[Claims] 1. In a torque detection device that detects torsion between an input shaft and an output shaft connected via a torsion bar, the torque detection device surrounds the input shaft or the output shaft, and includes an input shaft and an output shaft. a cylindrical coil core disposed to move in the axial direction as the cylindrical coil core rotates; a linear core connected across both ends of the cylindrical coil core; 1. A torque detection device comprising windings that are electromagnetically coupled to each of a shaped iron core and slidably wound individually.