JP2930683B2 - Torque detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a torque detecting device for a rotating shaft driven in rotation, and more particularly, to an on-vehicle device for determining the torque of a rotating shaft such as an automatic transmission of an automobile from the amount of twist of the shaft. A torque detecting device.

[Conventional technology]

In recent years, the need for torque detection in automobiles has been increasing. In particular, in an automatic transmission using a torque converter, a significant improvement in its characteristics is expected by detecting the torque of the output shaft. In a four-wheel drive vehicle, it is very important to detect the torque distribution between the front and rear wheels.

As a device for detecting the torque of such a rotating shaft,
2. Description of the Related Art A device that measures a torsion angle of a rotating shaft caused by a torque load and calculates a torque from the torsion angle by calculation is widely known. Generally, two rotary encoders are arranged on a rotating shaft to be measured at a predetermined distance in the axial direction, and a twist angle is obtained from a phase difference between output signals from both encoders. Calculating torque. As a rotary encoder, an encoder using optical means or an encoder using magnetic means is generally used. For example, Japanese Patent Application Laid-Open No. 62-239031 or Japanese Utility Model Application Laid-Open No. 150644/1987 discloses examples using a rotary encoder using a magnetic sensor.

[Problems to be solved by the invention]

However, the torque detection device using the rotary encoder described above has a problem that it is difficult to reduce the size of the device and a problem that accurate torque detection cannot be performed. The first factor that hinders high-precision detection is
This is an unavoidable mounting error when performing the work of mounting the rotary encoder on the rotating shaft. When such an attachment error exists, a phase difference is generated between the two rotary encoders even when there is no load. The second factor is a change with time of the rotating shaft itself. That is, torsional strain remains on the rotating shaft with time, and this is 2
This is an error with respect to the phase difference between the two rotary encoders.

To solve such a problem, Japanese Patent Application No. 1-254561
In the specification, a novel torque detecting device is disclosed. In this device, two magnetic recording media are provided at a predetermined distance from a rotation axis. Then, when there is no load, periodic signals having the same phase are written to the two magnetic recording media.
At the time of detecting the torque applied with the load, the periodic signal is read out, the phase difference is detected, the twist angle is obtained, and the torque is calculated from the twist angle. With such a configuration, the periodic signal can be rewritten at any time, so that accurate measurement can be performed without an error at the time of attachment or an error based on a change with time.

However, this device still has a problem to be solved. That is a method of mounting a magnetic head for recording and reproducing signals on a magnetic recording medium. In order to correctly record a signal on the magnetic recording medium, it is necessary to arrange the magnetic head and the magnetic recording medium so as to be in complete contact or extremely close to each other. However, when the magnetic recording medium is brought into complete contact, the magnetic recording medium rotates, so that abrasion or breakage occurs due to friction between the two. Therefore, in a general magnetic recording apparatus, the magnetic head is arranged at a position very close to the magnetic recording medium, and the magnetic head is supported by a resilient member having a gimbal structure so as to be finely movable. However, since the vibration of the vehicle body is transmitted to the rotating shaft of the automobile as it is, when the magnetic head is supported by an elastic member such as a gimbal structure, the magnetic head itself vibrates under the influence of the vibration of the vehicle body. For this reason, at the time of recording and reproduction, this vibration component is mixed as noise, and the detected torque value includes an error.

Therefore, an object of the present invention is to provide a torque detection device that is suitable for downsizing and that can detect an accurate torque that is not affected by vehicle body vibration.

[Means for solving the problem]

According to the present invention, in a torque detecting device, a first magnetic recording medium formed in a circumferential direction of a rotating shaft is provided at a predetermined interval in a circumferential direction of the rotating shaft with respect to the first magnetic recording medium. A second magnetic recording medium to be formed; a recording head integrally containing a pair of write sections for recording a predetermined position signal on both magnetic recording media; and a fine movement of the recording head in the immediate vicinity of the magnetic recording medium An elastic member supported on the first magnetic recording medium; a first reproducing head provided at a predetermined interval with respect to the first magnetic recording medium for reproducing a position signal recorded on the first magnetic recording medium; A second reproducing head provided at a predetermined interval with respect to the second magnetic recording medium in order to reproduce a position signal recorded on the magnetic recording medium, and providing a predetermined position signal to the recording head. To the first and second recording media Control means for performing two processes: a preparation process for recording; and a detection process for calculating a torque acting on the rotating shaft based on the phase difference between the position signals reproduced by the first and second reproduction heads; Is provided.

(Operation)

In the torque detecting device of the present invention, two magnetic recording layers are prepared at a predetermined interval on the rotation axis. A predetermined position signal is simultaneously recorded on the two magnetic recording layers by the recording head when the rotation axis is in a no-load state. Since the recording head is supported by the elastic member so as to be finely movable in the immediate vicinity of the magnetic recording layer, there is no abrasion or damage due to contact between the two. In addition, despite the fact that separate recording is performed on the two magnetic recording layers, this recording is performed simultaneously by an integrated recording head, so that position signals having the same phase are recorded on both magnetic recording layers. At the time of torque detection, a position signal is reproduced from the two magnetic recording layers by the reproducing head. The reproducing head is fixed to the housing at a predetermined distance from the magnetic recording layer. Therefore, even during signal reproduction, abrasion or breakage due to contact between the head and the magnetic recording layer does not occur. Further, since no elastic member is used for fixing the reproducing head, the influence of vehicle body vibration is extremely reduced. If the phase difference between the two position signals reproduced in this way is detected, the torsion angle of the rotation axis between the two magnetic recording layers can be accurately determined from the phase difference, and the rotation angle is added to the rotation axis based on the torsion angle. The torque can be determined accurately.

〔Example〕

Hereinafter, the present invention will be described based on the illustrated embodiments. FIG. 1 is a configuration diagram of a sensor unit of a torque detection device according to one embodiment of the present invention. This device has a function of detecting a torque applied to the rotating shaft 10. In this embodiment, the rotating shaft 10
Reference numeral denotes an output shaft of an automatic transmission for a vehicle. The left end of the figure is connected to a drive source, and the right end of the figure is connected to a load. On the outer peripheral surface of the rotating shaft 10, magnetic recording layers 11 and 12 are separated by a predetermined distance L.
Just formed. These magnetic recording layers can be formed by applying a magnetic paint in which a magnetic powder such as ferrite is dispersed in a resin binder such as an epoxy resin to a predetermined portion of the surface of the rotating shaft 10. A magnetic induction type recording head 20 is disposed immediately opposite the surfaces of the magnetic recording layers 11 and 12. On the surface opposite to the recording head 20, two magnetic induction type reproducing heads 30 and 40 are arranged at a predetermined interval. The recording head 20 is attached to a housing 60 (indicated by hatching in the figure) via an elastic member 50 and has a degree of freedom to move slightly in the vertical direction in the figure. , Despite being placed in the immediate vicinity of
No wear or damage occurs between the magnetic recording layers 11 and 12. The read heads 30 and 40 are fixed to the housing 60, but have a sufficient distance (50 to 200 μm in this embodiment) so as not to contact the magnetic recording layers 11 and 12. No wear or damage occurs between the magnetic recording layers 11 and 12.

A predetermined electric signal is given to the recording head 20 via the input terminal I, and a magnetic pattern is recorded on the magnetic recording layers 11 and 12 based on the electric signal. Also the playback head
30 and 40 read the magnetic patterns recorded on the magnetic recording layers 11 and 12, respectively, and output corresponding electric signals from the output terminals O1 and O2, respectively. Input terminal I and output terminal O
A control device to be described later is connected to 1, O2.

2 and 3 are diagrams showing the recording head 20 and its supporting structure shown in FIG. 1 more specifically.
FIG. 3 is a bottom view of the vicinity of the recording head 20, and FIG. 3 is a cross-sectional view taken along a cutting line 3-3. Recording head of this embodiment
2, two writing units 21 and 22 are provided in the unit 20, as shown in FIG. The writing units 21 and 22
Each has a function of writing to the magnetic recording layers 11 and 12. The electric signal applied to the input terminal I is simultaneously applied to both the write units 21 and 22, and the same magnetic pattern is recorded on the magnetic recording layers 11 and 12. In this embodiment, two gimbal plates 51 and 52 (hatched with dots in FIG. 2) are used as the elastic member 50, and the recording head 20 is attached to the housing 60. As described above, when both sides of the recording head 20 are attached to the housing 60 with the gimbal plates 51 and 52,
The recording head 20 has a degree of freedom to move minutely in the left-right direction in FIG. 3, but hardly moves in the twisting direction in the plane in FIG. Such a structure allows the magnetic recording layer 11 to be used even when the vehicle body is vibrating in a recording operation described later.
And 12 can be written with in-phase magnetic patterns.

Now, the operation of torque detection by this device will be described. This detection operation includes two steps: a preparation step of writing a predetermined magnetic pattern on the magnetic recording layers 11 and 12, and a detection step of reading the magnetic patterns from the magnetic recording layers 11 and 12 at the same time. The preparation stage is performed as follows in a state where the rotating shaft 10 is being released from the load and rotating. First, a predetermined periodic signal is supplied to the input terminal I from a control device (not shown). The recording head 20 records a magnetic pattern on the magnetic recording layers 11 and 12 based on the periodic signal.
Since the magnetic recording layers 11 and 12 are both rotating together with the rotation axis 10, magnetic patterns having the same phase are recorded on both. As described above, since the recording head 20 is integrally supported so as to perform a minute movement with a degree of freedom in the vertical direction in FIG. The phase of the magnetic pattern is not shifted. The magnetic pattern thus recorded has information indicating a recording position on the magnetic recording layer. Hereinafter, in the present specification, the information recorded as the magnetic pattern will be referred to as a position signal.

As described above, if the in-phase position signals are written in the magnetic recording layers 11 and 12, the subsequent detection step can be performed. This detection step is performed as follows with a load applied to the rotating shaft 10. First, the reproducing heads 30 and 40 simultaneously read the position signals from the magnetic recording layers 11 and 12, respectively, and output these to the output terminals O1 and O2, respectively. A control circuit (not shown) detects the phase difference between the two position signals output in this manner, and determines the torque applied to the rotating shaft 10 based on the phase difference. If no load is applied to the rotating shaft 10, no torque is generated. Therefore, the position signal S30 reproduced by the reproducing head 30 and the position signal S40 reproduced by the reproducing head 40 become synchronized signals as shown in FIG. 4, and the phase difference is 0. However, when a load is applied to the rotating shaft 10, torque is generated, and the rotating shaft 10 is twisted. This amount of twist is proportional to the phase difference between the position signals S30 and S40. Therefore, the principle of the torque detection of this device is to detect the phase difference, obtain the amount of twist based on the phase difference, and obtain the applied torque. More specifically, the control device calculates the torque value as follows. First, the phase difference Δt between the position signals S30 and S40
Is detected in units of time. The relationship between the phase difference Δt obtained in units of time and the torsion angle θ of the rotating shaft is given by θ = 2πΔt N (1). Here, N is the number of rotations of the rotating shaft per unit time. This rotation speed N can be obtained as follows. That is, if the number of rotations of the rotating shaft when the position signal is written in the preparation stage is N0, the frequency of the written position signal is f0, and the frequency of the position signal read in the detection stage is f, N = (f / f0) / N0 (2) The rotation speed N per unit time in the detection stage is obtained by the following expression. Thus, if the torsion angle θ is obtained from the expressions (1) and (2), the torque T is calculated by the expression: T = 2πθGd ⁴ / 64L (3) Therefore, if the equation (1) is substituted into the equation (3), the torque T can be obtained by the following equation: T = π ² Gd ⁴ · Δt · N / 16L (4) Here, G is the transverse elastic coefficient of the rotating shaft, d is the diameter of the rotating shaft, and L is the magnetic recording layers 11 and 12.
Is the distance between

A first feature of the torque detecting device according to the above-described embodiment is that the recording head for writing the position signal to the two magnetic recording layers has an integral structure supported by an elastic member. The second feature is that the reproducing head for reading the position signal from the two magnetic recording layers is fixed to the housing at a predetermined distance from the magnetic recording layers. On the point.
Therefore, even if a vehicle body signal is generated, no wear or breakage occurs between each head and the magnetic recording layer, and no influence of the vehicle body vibration appears on the position signal during recording or reproduction. For reference, FIG. 5 shows a structure in which two magnetic heads for both recording and reproduction are provided, and both are supported by elastic members. Magnetic recording layers 11 and 12 are formed on a rotating shaft 10 as in the embodiment of the present application. On the one hand, a first recording / reproducing head 70 is attached to the housing 60 by means of an elastic member 75 for recording / reproducing a position signal on / from the magnetic recording layer 11, and on the other hand, recording / reproducing a position signal on the magnetic recording layer 12. For this purpose, the second recording / reproducing head 80 is
Attached to the housing 60. In such a structure, since the elastic member is used, no wear or breakage occurs between the head and the magnetic recording layer, but the vibration component of the vehicle body greatly affects the position signal. FIG. 6 shows a position signal when a predetermined position signal is recorded in a state where no load is applied to the rotating shaft 10 using the apparatus shown in FIG. 5 and is reproduced in a state where no load is applied. It is a graph. The signal S70 is a position signal reproduced by the first recording / reproducing head 70, and the signal S80 is a position signal reproduced by the second recording / reproducing head. As shown in the figure, not only the signal strength becomes unstable, but also a phase difference that should not occur between the two occurs. In such a structure, when the position signal is first recorded, the two heads 70 and 80 affected by the body vibration vibrate separately, so that the position signal itself recorded on the magnetic recording layers 11 and 12 has already been recorded. It has a phase difference. Further, when reproducing this, since the reproduction operation is separately performed under the influence of the vehicle body vibration, a reproduced signal greatly influenced by the vehicle body vibration is obtained as a result. According to the embodiment of the present invention described above,
Recording and reproduction can be performed while suppressing the influence of such vehicle body vibration as much as possible, and accurate torque detection can be performed.

As described above, the present invention has been described based on one embodiment illustrated in the drawings. However, the present invention is not limited to this embodiment, and can be implemented in various modes. For example, in the above-described embodiment, a recording head having two writing portions (two-track magnetic head) is used, but the magnetic recording layers 11 and 12 are used.
When the distance L from the head is relatively short, recording is simultaneously performed on the two magnetic recording layers with a single writing portion using a recording head (a one-track magnetic head) having a single wide writing portion. You may do so.

〔The invention's effect〕

As described above, according to the torque detection device of the present invention, the integrated recording head for writing the position signal to the two magnetic recording layers is supported by the elastic member in the vicinity of the magnetic recording layer to read the position signal. The reproducing head is provided separately from the magnetic recording layer at a predetermined distance, so that even if a vehicle signal is generated, there is no abrasion or breakage between each head and the magnetic recording layer, and the vehicle vibration Accurate torque detection that does not receive an error due to the influence of the above becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a torque detecting device according to an embodiment of the present invention, FIG. 2 is a bottom view around the recording head 20 of the device shown in FIG. 1, and FIG. Sectional view cut by 3,
FIG. 4 is a graph showing a reproduced signal at the time of no-load rotation in the apparatus shown in FIG. 1, FIG. 5 is a configuration diagram of an apparatus having a structure in comparison with the embodiment shown in FIG. 1, and FIG. 4 is a graph showing a reproduction signal at the time of no-load rotation in the apparatus shown in the figure. 10 ... rotary axis, 11,12 ... magnetic recording layer, 20 ... recording head, 21,22 ... writing unit, 30 ... first reproducing head, 4
0 ... second reproducing head, 50 ... elastic member, 51,52 ... gimbal plate, 60 ... housing, 70 ... first recording / reproducing head, 75 ... elastic member, 80 ... second Recording / reproducing head, 85: elastic member, I: input terminal, O1, O2: output terminal.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01L 3/10

Claims (1)

(57) [Claims] A first magnetic recording medium formed in a circumferential direction of a rotating shaft; and a first magnetic recording medium formed in the circumferential direction of the rotating shaft at a predetermined interval in an axial direction with respect to the first magnetic recording medium. A second magnetic recording medium to be recorded; a recording head integrally containing first and second write units for recording a predetermined position signal on the first and second magnetic recording media; An elastic member for supporting the first and second magnetic recording media so as to be finely movable in close proximity to the first and second magnetic recording media; and for reproducing the position signal recorded on the first magnetic recording medium, A first reproducing head provided at a predetermined interval from the second magnetic recording medium, and a first reproducing head provided at a predetermined interval to the second magnetic recording medium to reproduce a position signal recorded on the second magnetic recording medium. Second read head, and the recording head A preparatory process for giving a predetermined position signal and recording the same on the first and second recording media; and applying a predetermined position signal to the rotation axis based on a phase difference between the position signals reproduced by the first and second reproduction heads. And a control means for performing two kinds of processing, namely, a detection processing for calculating an acting torque.