JP2005201712A - Detection device of rotation angle and torque - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a torque, while detecting a rotation angle, and especially to heighten detection accuracy of the torque, in a detection device of the rotation angle and the torque applied to a shaft or a steering shaft. <P>SOLUTION: This device has a constitution wherein the first detection gear 11a is engaged with the first main gear 10a and the second detection gear 11b is engaged with the second main gear 10b respectively, and a torsion bar 12 is provided between the first detection gear 11a and the second detection gear 11b, and the third detection gear 11c is also provided. Consequently, when detecting a torque, a processing error of the gear or an error caused by installation does not enter, to thereby heighten the detection accuracy of the sensor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rotation angle and a torque detection device for detecting a rotation angle of a shaft or a steering shaft and a torque applied thereto.

  Conventionally, this type of detection apparatus has a configuration as shown in FIG. In FIG. 8, a torsion bar 120 for measuring torque is formed at an intermediate portion of the shaft 110. The shaft 110 is provided with a gear 102. A gear 103 and a gear 104 are engaged with the gear 102. A sleeve 122 extends from the attachment portion 121 in the direction of the gear 102, and a gear 123 is provided at an end thereof. The gear 123 has the same number of teeth n as the gear 102. Further, a gear 124 is engaged with the gear 123, and the gear 124 has the same number of teeth m as the gear 103. In the vicinity of the gear 103, the gear 124, and the gear 104, although not shown, a magnet and a corresponding magnetic sensor are provided.

  When torque acts on the torsion bar 120, the gear 102 and the gear 123 rotate relative to each other, thereby causing a difference in the rotation angle of the gear 124 having the same number of teeth with respect to the rotation angle of the gear 103. By calculating the angle change from the difference between the rotation angles of the gear 103 and the gear 124, the acting torque can be detected.

  This angle change amount is set to about 3 degrees each for left rotation and right rotation so that the driver does not feel uncomfortable in the relationship between the steering wheel and the tire when steering the steering wheel.

  Further, the gear 103 and the gear 104 have slightly different numbers of teeth, whereby the absolute position of the rotation angle can be determined over multiple rotations of the shaft 110.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
International Publication No. 00/08434 Pamphlet

  However, in the conventional configuration described above, torque is generated in the torsion bar 120 provided on a part of the main shaft 110 and the torsion angle is detected. However, since the torsion angle is small, it is greatly affected by machining errors in the gear transmission portion. As a result, the detection accuracy deteriorates.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a rotation angle and torque detection device with high detection accuracy.

  In order to achieve the above object, the present invention has the following configuration.

  According to the first aspect of the present invention, the steering shaft is divided into a first steering shaft and a second steering shaft, and a limiter portion is provided between the first steering shaft and the second steering shaft. The first main gear and the second main gear with m teeth are arranged on the first steering shaft and the second steering shaft, respectively, and the number of teeth n engaged with the first main gear is arranged. A first detection gear, a second detection gear with n teeth engaged with the second main gear, and a third detection gear with p teeth engaged with the first detection gear. And a torsion bar is disposed between the first detection gear and the second detection gear, and faces the first detection gear, the second detection gear, and the third detection gear, respectively. A first rotation angle detection unit, a second rotation angle detection unit, and a third rotation angle detection unit, and the first rotation angle detection unit and the second rotation angle detection unit, By configuring the torque to be detected by the first rotation angle detection unit and the third rotation angle detection unit, respectively, an effect of being able to accurately detect the torque together with the rotation angle is obtained. It is done.

  According to a second aspect of the present invention, the steering shaft is divided into a first steering shaft and a second steering shaft, and a limiter portion is provided between the first steering shaft and the second steering shaft. The first main gear and the second main gear with m teeth are arranged on the first steering shaft and the second steering shaft, respectively, and the number of teeth n engaged with the first main gear is arranged. A first detection gear, a second detection gear having n teeth engaged with the second main gear, and a third detection gear having p teeth engaged with the first main gear. And a torsion bar is disposed between the first detection gear and the second detection gear, and is opposed to the first detection gear, the second detection gear, and the third detection gear, respectively. A first rotation angle detection unit, a second rotation angle detection unit, and a third rotation angle detection unit, and the first rotation angle detection unit and the second rotation angle detection unit Since the rotation angle is detected by the first rotation angle detection unit and the third rotation angle detection unit, the torque can be accurately detected together with the rotation angle. It is done.

  According to a third aspect of the present invention, the fourth detection gear having the number of teeth q is disposed so as to engage with the third detection gear, and the fourth rotation is opposed to the fourth detection gear. An angle detection unit is provided, and the first rotation angle detection unit and the second rotation angle detection unit detect torque, and the third rotation angle detection unit and the fourth rotation angle detection unit detect rotation angles, respectively. With such a configuration, it is possible to obtain an operational effect that the torque can be accurately detected together with the rotation angle.

  According to a fourth aspect of the present invention, the fourth detection gear having the number of teeth q is arranged so as to engage with the first main gear, and the fourth rotation is opposed to the fourth detection gear. An angle detection unit is provided, and the first rotation angle detection unit and the second rotation angle detection unit detect torque, and the third rotation angle detection unit and the fourth rotation angle detection unit detect rotation angles, respectively. With such a configuration, it is possible to obtain an operational effect that the torque can be accurately detected together with the rotation angle.

  The invention according to claim 5 of the present invention is such that the number of teeth m of the first main gear and the second main gear is larger than the number of teeth n of the first detection gear and the second detection gear. Since the rotation angle of the detection gear can be increased, an effect of further improving the torque detection accuracy can be obtained.

  In the invention according to claim 6 of the present invention, the ratio of the number of teeth m of the main gear to the number of teeth n of the detection gear is set to 2 to 5: 1. The effect is that the measurement accuracy is increased by a factor of two.

  According to the seventh aspect of the present invention, the number n of teeth of the first detection gear is slightly larger or slightly smaller than the number p of teeth of the third detection gear. The direction of the magnet gradually changes as the handle is rotated, and a phase difference due to the rotation is generated. By reading this with a magnetic detection element, the absolute rotation angle over multiple rotations of the handle can be detected. The effect is obtained.

  In the invention according to claim 8 of the present invention, the number of teeth p of the third detection gear is slightly larger or slightly smaller than the number of teeth q of the fourth detection gear. The direction of the magnet gradually changes as the handle is rotated, and a phase difference due to the rotation is generated. By reading this with a magnetic detection element, the absolute rotation angle over multiple rotations of the handle can be detected. The effect is obtained.

  The rotation angle and torque detection device of the present invention has an effect that torque detection error due to mechanical error is small and torque can be detected with high accuracy together with the rotation angle.

  FIG. 1 is a perspective view showing a part of a steering system of a vehicle. As shown in FIG. 1, a rotation angle and torque detection device 8 is arranged on a steering shaft 1 as a steering shaft of a vehicle connected to a handle 2, and a pinion 3 provided at the tip of the steering shaft 1 and a connecting rod 5 are provided. The rack 4 is connected. Tires 6 are provided on the left and right sides of the connecting rod 5 and the axle 7.

  The steering force generated when the driver steers the steering wheel 2 is detected by a rotation angle and torque detection device 8 attached to the steering shaft 1 and further transmitted from the pinion 3 to the tire 6 via the rack 4. The

  2A and 2B are a top view and a front view showing details of the rotation angle and torque detection device 8 of the present invention. In FIG. 2B, the steering shaft is divided into two in the longitudinal direction, and is divided into a steering wheel side first steering shaft 9a and a tire side second steering shaft 9b.

  A first main gear 10a is coaxially provided on the first steering shaft 9a, and a second main gear 10b is coaxially provided on the second steering shaft 9b. A first detection gear 11a is engaged with the first main gear 10a, and a second detection gear 11b is engaged with the second main gear 10b. The first detection gear 11a and the second detection gear 11b are arranged at both ends of the torsion bar 12, respectively. The shaft of the torsion bar 12 is arranged in parallel with the steering shaft. The number of teeth of the first main gear 10a and the second main gear 10b is set to m, and the number of teeth of the first detection gear 11a and the second detection gear 11b is set to n. The ratio of the number of teeth m to the number of teeth n is set to 2 to 5: 1.

  A first magnet 13a and a second magnet 13b are provided at the rotation center of the first detection gear 11a and the rotation center of the second detection gear 11b. A first magnetic detection element 15a is provided on the circuit board 14a at a position facing the first magnet 13a, and a second magnetic detection element 15b is arranged at a position facing the second magnet 13b. It is provided on the substrate 14b. The first magnet 13a and the first magnetism detection element 15a constitute a first rotation angle detection unit, and the second magnet 13b and the second magnetism detection element 15b constitute a second rotation angle detection unit. Yes.

  The first steering shaft 9a and the second steering shaft 9b are held so as to rotate smoothly by bearings 16a and 16b, respectively. The first detection gear 11a, the second detection gear 11b, and the torsion bar 12 are held by the bearings 17a and 17b so as to rotate smoothly. And each bearing 16a, 16b, 17a, 17b is each hold | maintained at the housing | casing (not shown). A limiter portion 18 is provided at the coupling portion between the first steering shaft 9a and the second steering shaft 9b.

  A third detection gear 11c is engaged with the first detection gear 11a. The number of teeth p of the third detection gear 11c is slightly larger than the number of teeth n of the first detection gear 11a. A third magnet 13c is provided at the rotation center of the third detection gear 11c. A third magnetic detection element 15c is provided on the rotating substrate 14a so as to face the third magnet 13c. The third magnet 13c and the third magnetic detection element 15c constitute a third rotation angle detection unit.

  FIG. 3 is a cross-sectional view of the limiter portion 18 in FIG. Reference numeral 19 denotes a groove provided at the end of the first steering shaft 9a of the limiter unit 18. Reference numeral 20 denotes a convex portion provided at an end portion of the second steering shaft 9b of the limiter portion 18. The width of the convex portion 20 is set narrower than the width of the groove portion 19 and is coupled with a gap t.

  FIG. 4 is a cross-sectional view showing the state of the lines of magnetic force from the magnets of the first rotation angle detector, and goes out of the first magnet 13a and passes through the first magnetic detection element 15a via the first detection gear 11a. The path | route of the magnetic force line 21 is shown. The same applies to the magnetic field lines of the second magnet 13b and the third magnet 13c.

  Next, the operation of the rotation angle and torque detection device 8 will be described.

  In FIG. 2 (b), when the handle 2 is turned, the first steering shaft 9a rotates, and the rotation is transmitted from the first main gear 10a to the first detection gear 11a, and further through the torsion bar 12, the second It is transmitted to the detection gear 11b and further transmitted to the second main gear 10b to rotate the second steering shaft 9b.

  During this time, the magnetic lines of force 21 emitted from the first magnet 13a rotate while changing the direction in the first magnetic detection element 15a. The first magnetic detection element 15 a detects the direction of the magnetic force lines 21. Similarly, the second magnetic detection element 15b detects the direction of the magnetic force line 21 of the second magnet 13b, and the third magnetic detection element 15c detects the direction of the magnetic force line 21 of the third magnet 13c. When a load torque is generated on the second steering shaft 9b, the torsion bar 12 is twisted according to the load torque. As a result, the outputs of the first magnetic detection element 15a and the second magnetic detection element 15b A relative difference is generated, and the magnitude of the load torque applied to the torsion bar 12 can be calculated by a calculation circuit (not shown) on the circuit board 14a based on the magnitude of the difference.

  When a load torque exceeding a predetermined magnitude is applied, the gap t between the limiter portions 18 becomes 0, and the first steering shaft 9a and the second steering shaft 9b are directly connected in terms of torque and exceed a predetermined magnitude. All the load torque is directly transmitted from the first steering shaft 9a to the second steering shaft 9b. This prevents the torsion bar 12 from being damaged due to excessive torque. The gap t is set so as to correspond to a twist angle of about 3 degrees in both the clockwise and counterclockwise directions between the first steering shaft 9a and the second steering shaft 9b so that the steering feel does not feel strange. It is.

  Further, by setting the ratio of the number of teeth of the main gears 10a, 10b and the detection gears 11a, 11b to about 2 to 5: 1, the twist angle of the steering shaft is expanded 2-5 times in the detection gears 11a, 11b. Therefore, the measurement accuracy with the magnetic detection elements 15a and 15b is increased accordingly.

  The rotation angle and the signal detected by the torque detection device 8 are boosted by a steering assist mechanism (not shown) and applied to the second steering shaft 9b. It will be possible to operate.

  Next, the effectiveness of the rotation angle and torque detection device 8 of the present invention will be described.

  The advantage of the rotation angle and torque detection device 8 of the present invention is that there is less torque detection error due to mechanical error compared to the conventional system in which a torsion bar is provided coaxially with the steering shaft. The torque detection accuracy is excellent.

  The load torque needs to be detected within a small twisting range of 3 degrees on the left and right of the steering shaft. However, in the conventional example, errors caused by gear machining errors and mounting errors in the process of gear transmission to the detection gear are not required. There is an influence of about 10%, and the error is doubled and added to the steering shaft. Therefore, it is difficult to handle the steering wheel at a subtle angle due to the uncomfortable feeling when turning the steering wheel. In the rotation angle and torque detection device 8, the torsion generated in the torsion bar 12 can be directly detected by the first magnetic detection element 15a and the second magnetic detection element 15b. It is uniquely determined, and the torque value and the signal value correspond exactly to each other so that the influence of the error due to transmission of the gear does not enter. In this way, it is possible to detect load torque with high accuracy.

  Further, the third detection gear 11c engaged with the first detection gear 11a has a number of teeth p that is slightly larger than the number of teeth n of the first detection gear 11a. The direction of the magnet is changed little by little as it is rotated, and a phase difference due to the rotation is generated. By reading this with the first magnetic detection element 15a and the third magnetic detection element 15c, the rotation of the handle 2 is performed. The absolute rotation angle can be detected.

  Further, as shown in FIG. 5, the first detection gear 11a having the number of teeth n and the third detection gear 11d having the number of teeth p are both engaged with the first main gear 10a. Even if the first magnetic detection element 15a and the third magnetic detection element 15d are provided at positions corresponding to the detection gear 11a and the third detection gear 11d and the rotation angle is detected between them, the same effect can be obtained. It is what

  Further, as shown in FIG. 6, the rotation angle is detected by detecting the third detection gear 11e having the number of teeth p, the fourth detection gear 11f having the number of teeth q engaged therewith, and the third magnetic gears corresponding thereto. The detection element 15e and the fourth magnetic detection element 15f may be provided exclusively for execution.

  Further, as shown in FIG. 7, the rotation angle is detected by a third detection gear 11g and a fourth detection gear 11h that are respectively engaged with the main gear 10a, and a third magnetic detection element 15g corresponding to each of them. The fourth magnetic detection element 15h may be provided exclusively for execution.

  In the rotation angle and torque detection device according to the present invention, the first detection gear is engaged with the first main gear, and the second detection gear is engaged with the second main gear. By providing a torsion bar between the gear and the second detection gear, and further providing a third detection gear or a fourth detection gear, torque detection is caused by gear machining errors or attachment. This is useful for in-vehicle electric power steering devices and attitude control because the detection accuracy of the sensor can be increased and the rotation angle of the steering wheel can be detected at the same time. .

The perspective view of the steering system of the vehicle which attached the rotation angle and torque detection apparatus of this invention (A) Top view of the same rotation angle and torque detection device, (b) Front view of the same rotation angle and torque detection device Sectional view of the limiter part of the rotation angle and torque detector Sectional drawing which shows the mode of the magnetic force line from the magnet of the same rotation angle and rotation angle detection part of a torque detector The block diagram which shows other embodiment of the rotation angle and torque detection apparatus The block diagram which shows another embodiment of the rotation angle and torque detection apparatus Configuration diagram showing another embodiment of the rotation angle and torque detection device Configuration diagram of conventional rotation angle and torque detection device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering shaft 2 Handle 3 Pinion 4 Rack 5 Connecting rod 6 Tire 7 Axle 8 Rotation angle and torque detection device 9a First steering shaft 9b Second steering shaft 10a First main gear 10b Second main gear 11a First Detection gear 11b second detection gear 11c, 11d, 11e, 11g third detection gear 11f, 11h fourth detection gear 12 torsion bar 13a first magnet 13b second magnet 13c third magnet 14a, 14b Circuit board 15a First magnetic detection element 15b Second magnetic detection element 15c, 15d, 15e, 15g Third magnetic detection element 15f, 15h Fourth magnetic detection element 16a, 16b, 17a, 17b Bearing 18 Limiter unit 19 Groove part 20 Convex part 21 Line of magnetic force

Claims (8)

The steering shaft is divided into a first steering shaft and a second steering shaft, and a limiter portion is disposed between the first steering shaft and the second steering shaft, and the first steering shaft and the second steering shaft are arranged. The first main gear and the second main gear with m teeth are respectively arranged on the steering shaft of the first detection gear with the number n of teeth engaged with the first main gear, and the second A second detection gear having n teeth engaged with the main gear and a third detection gear having p teeth engaged with the first detection gear are arranged, and the first detection gear and the first detection gear are arranged. A torsion bar is disposed between the first detection gear, the second detection gear, and the third detection gear, respectively, and the first rotation angle detection unit and the second detection gear are respectively opposed to the first detection gear, the second detection gear, and the third detection gear. A rotation angle detection unit and a third rotation angle detection unit are provided, and torque is detected by the first rotation angle detection unit and the second rotation angle detection unit. A rotational angle and torque detecting device configured to detect respective rotation angles at said third rotational angle detector. The steering shaft is divided into a first steering shaft and a second steering shaft, and a limiter portion is disposed between the first steering shaft and the second steering shaft, and the first steering shaft and the second steering shaft are arranged. The first main gear and the second main gear with m teeth are respectively arranged on the steering shaft of the first detection gear with the number n of teeth engaged with the first main gear, and the second A second detection gear having n teeth engaged with the main gear and a third detection gear having p teeth engaged with the first main gear are arranged, and the first detection gear and the first detection gear are arranged. A torsion bar is disposed between the first detection gear, the second detection gear, and the third detection gear, respectively, and the first rotation angle detection unit and the second detection gear are respectively opposed to the first detection gear, the second detection gear, and the third detection gear. A rotation angle detection unit and a third rotation angle detection unit are provided, and torque is generated by the first rotation angle detection unit and the second rotation angle detection unit. The third rotational angle and torque detecting device configured to detect respectively a rotational angle and the rotation angle detecting unit. The steering shaft is divided into a first steering shaft and a second steering shaft, and a limiter portion is disposed between the first steering shaft and the second steering shaft, and the first steering shaft and the second steering shaft are arranged. The first main gear and the second main gear with m teeth are respectively arranged on the steering shaft of the first detection gear with the number n of teeth engaged with the first main gear, and the second A second detection gear with n teeth engaged with the main gear, a third detection gear with teeth p engaged with the first main gear, and the number of teeth engaged with the third detection gear a fourth detection gear of q, a torsion bar is arranged between the first detection gear and the second detection gear, and the first detection gear, the second detection gear, and the A first rotation angle detection unit, a second rotation angle detection unit, a third rotation angle detection unit, and a fourth rotation angle detection are respectively opposed to the third detection gear and the fourth detection gear. A rotation angle between the first rotation angle detection unit and the second rotation angle detection unit, and a rotation angle between the third rotation angle detection unit and the fourth rotation angle detection unit, respectively. A rotation angle and torque detection device configured to detect. The steering shaft is divided into a first steering shaft and a second steering shaft, and a limiter portion is disposed between the first steering shaft and the second steering shaft, and the first steering shaft and the second steering shaft are arranged. The first main gear and the second main gear with m teeth are respectively arranged on the steering shaft of the first detection gear with the number n of teeth engaged with the first main gear, and the second A second detection gear with n teeth engaged with the main gear, a third detection gear with p teeth engaged with the first main gear, and the number of teeth engaged with the first main gear a fourth detection gear of q, a torsion bar is arranged between the first detection gear and the second detection gear, and the first detection gear, the second detection gear, and the A first rotation angle detection unit, a second rotation angle detection unit, a third rotation angle detection unit, and a fourth rotation angle detection that face the third detection gear and the fourth detection gear, respectively. The first rotation angle detection unit and the second rotation angle detection unit detect torque, and the third rotation angle detection unit and the fourth rotation angle detection unit detect rotation angles, respectively. A rotation angle and torque detection device configured to perform. The rotation angle according to any one of claims 1 to 4, wherein the number of teeth m of the first main gear and the second main gear is larger than the number of teeth n of the first detection gear and the second detection gear. And torque detection device. The rotation angle and torque detection device according to claim 5, wherein the ratio of the number of teeth m to the number of teeth n is 2 to 5: 1. The rotation angle and torque detection device according to claim 1 or 2, wherein the number n of teeth of the first detection gear is slightly larger or slightly smaller than the number p of teeth of the third detection gear. The rotation angle and torque detection device according to claim 3 or 4, wherein the number of teeth p of the third detection gear is slightly larger or slightly smaller than the number of teeth q of the fourth detection gear.

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