JP4144657B2 - Rotation detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotation detection device. This rotation detection device is used, for example, to detect the rotation speed of a vehicle wheel, and is used as information input means in an automobile ABS (anti-lock brake system).
[0002]
[Prior art]
In general, the ABS of an automobile needs information such as the rotation speed of a wheel. For example, in order to detect the rotation speed of a wheel, a rotation detection device is incorporated in a hub unit for an axle, for example.
[0003]
The rotation detection device is attached to the rotation side of the axle and a plurality of windows are provided at equal intervals around the pulsar ring, and is attached to the non-rotation side of the axle so as to face the pulsar ring and passes through the window of the pulsar ring. A single electromagnetic sensor that outputs a corresponding magnetic force change as an electrical signal (analog signal of a sine curve), and a control unit that includes a microcomputer that calculates the rotational speed of the wheel based on the electrical signal output from the electromagnetic sensor; Consists of.
[0004]
In the above-described control unit, the process of recognizing the cycle of one wheel rotation and the process of recognizing the frequency change of the electrical signal for each recognized wheel rotation and obtaining the rotation speed of the wheel are performed in parallel. In the process of recognizing the period of one rotation of the wheel, the electric signal output from the electromagnetic sensor is taken, this electric signal is A / D converted, the number of pulses is counted, and this count value is compared with a required reference value. Like to do.
[0005]
[Problems to be solved by the invention]
In the above-described conventional technique, two different processes are simultaneously performed in the control unit, and therefore, wastefulness such as the need to use an expensive unit having a large processing capacity as the control unit occurs.
[0006]
Therefore, an object of the present invention is to enable the rotation detection device to detect the rotation speed of a rotating body without using an expensive control unit having a large processing capacity.
[0007]
[Means for Solving the Problems]
A rotation detection device according to claim 1 of the present invention is a pulsar ring fixed to a rotator and provided with a plurality of windows at equal circumferential intervals excluding a required circumferential angle region, and a state in which the pulsar ring is disposed so as not to contact the pulsar ring An electromagnetic sensor that is fixed to the non-rotating member and outputs a change in magnetic force according to a relative position with respect to the pulsar ring as an electric signal, a period detecting unit that detects a period of one rotation of the rotating body based on the output of the electromagnetic sensor, In the rotation detection device including a control unit for recognizing the rotation speed of the rotating body based on the output from the detection unit and the output of the electromagnetic sensor, the electromagnetic sensor has a predetermined interval on the inner peripheral side with respect to the pulsar ring. The annular yoke made of a magnetic material, an annular permanent magnet, and a detection coil wound around the annular yoke. Facing the plurality of windows of the pulser ring in the interval, is formed a plurality of convex teeth have the shape error in manufacturing, the required angle region of the pulser ring, a larger opening than the opening of a window provided in the other region A window is provided, and the period detection unit is configured to detect an output signal from the detection coil of the electromagnetic sensor using envelope detection means for detecting an envelope, a rectangular pulse based on an output of the envelope detection means and a required reference value Pulse signal generating means for generating a signal.
[0009]
In the rotation detection device described above, the period of one rotation of the rotating body is detected by using an electric signal output from the electromagnetic sensor by a period detection unit provided at a preceding stage of the control unit. And as a control part, only the process which calculates | requires the rotational speed of a rotary body based on the pulse signal given from a period detection part and the electrical signal given from an electromagnetic sensor is performed.
[0010]
In short, since the control unit is configured to perform a single process without performing two processes simultaneously in parallel as in the prior art, the burden on the control unit can be reduced.
[0011]
In particular, in the present invention, the waveform amplitude of the electric signal output from the electromagnetic sensor is changed by enlarging the window only for the required angle region without providing the window at equal intervals around the pulsar ring. A rectangular pulse signal is generated by the period detector using the change in amplitude. In this case, in order to change the waveform amplitude, there is no need to provide an extra protrusion or a separate extra part in the pulsar ring.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Details of the present invention will be described below based on the embodiment shown in FIGS.
[0013]
1 to 4 according to an embodiment of the present invention, FIG. 1 is a block diagram showing a configuration of a rotation detection device, FIG. 2 is an exploded perspective view showing a part of an electromagnetic sensor and a pulsar ring, and FIG. FIG. 4 is a conceptual diagram showing an induced voltage waveform corresponding to the magnetic force intensity at each convex tooth of the annular yoke of the electromagnetic sensor.
[0014]
In the figure, A indicates the entire rotation detection device, 1 is a pulsar ring, 2 is an electromagnetic sensor called a multi-pole type, 3 is a period detector for detecting the period of one rotation of a rotating body (not shown), and 4 is a micro A control unit comprising a computer.
[0015]
The pulsar ring 1 is attached to a rotating body (not shown) and is made of a ring made of a magnetic material. As shown in FIG. 2, the pulsar ring 1 here is provided with rectangular small windows 11A at equal circumferential intervals except for the required angle region, and a single large window 11B is provided in the required angle region. Is provided. The circumferential length of the large window 11B is such that a plurality of (in this example, two) small windows 11A are cut off from each other so that a plurality of small windows 11A are connected in communication. Is set to
[0016]
The electromagnetic sensor 2 is disposed opposite to the inner peripheral side of the pulsar ring 1 with a predetermined interval, and includes an annular yoke 21 made of a magnetic material, an annular permanent magnet 22, and a detection coil 23. The change in the magnetic strength of the permanent magnet 22 corresponding to the change in the relative position of the pulsar ring 1 with respect to 21 is output as an electric signal. As shown in FIG. 2, the annular yoke 21 has a two-piece structure in which an annular plate 25 is joined to the other axial end of the annular body 24 having an annular plate portion 24 a radially outward at one axial end. A plurality of convex teeth 26 are formed on the outer peripheries of the annular plate portion 24a and the annular plate 25 at equal intervals around the circumference. A permanent magnet 22 is joined to the end face of the annular plate 25 of the annular yoke 21, and a detection coil 23 is wound around the outer periphery of the annular body 24 of the annular yoke 21.
[0017]
The period detection unit 3 includes an envelope detection circuit 31 that detects an electric signal output from the electromagnetic sensor 2, an output of the envelope detection circuit 31, and an output of the reference voltage generation circuit 33. And a comparator 32 that inputs the data to the control unit 4.
[0018]
The control unit 4 recognizes the frequency change of the electric signal supplied from the electromagnetic sensor 2 during the period from the rising or falling edge of the pulse signal supplied from the comparator 32 to the next rising or falling edge, and rotates the rotating body (not shown). Process to find the speed.
[0019]
Next, the operation of the above rotation detection device A will be described.
[0020]
When the pulsar ring 1 rotates in synchronization with the rotation of a rotating body (not shown), the large and small windows 11A and 11B of the pulsar ring 1 are respectively connected to the pair of convex teeth 26 and 26 of the annular yoke 21 of the electromagnetic sensor 2 in the non-rotating state. The opposing position of each will change one by one.
[0021]
That is, with the rotation of the pulsar ring 1, the large and small windows 11A and 11B of the pulsar ring 1 are alternately opposed to the pair of convex teeth 26 and 26 opposed in the axial direction of the annular yoke 21 of the electromagnetic sensor 2. The partition portion between the large and small windows 11A and 11B is in a state of facing each other. In each of these states, the magnetic strength of the magnetic field formed between the permanent magnet 22, the annular yoke 21 and the pulsar ring 1 changes strongly and weakly. A sinusoidal analog electric signal as shown in a) is output.
[0022]
Since each convex tooth 26 of the annular yoke 21 has a manufacturing shape error, this shape error also causes the above-described change in the waveform amplitude. By the way, the electrical signals corresponding to the magnetic strengths of the plurality of convex teeth 26 are virtually as shown in FIGS. 4A to 4N, for example. It is output from the detection coil 23 as shown in a).
[0023]
Then, the electrical signal sequentially output from the electromagnetic sensor 2 is converted into an envelope waveform signal as shown in FIG. 3B by the envelope detection circuit 31 of the period detector 3, and the comparator 32 displays the signal shown in FIG. The rectangular pulse signal as shown in c) is input to the control unit 4.
[0024]
The control unit 4 is given not only the pulse signal generated by the period detection unit 3 but also an electric signal output from the electromagnetic sensor 2. Here, the control unit 4 recognizes the frequency change of the electric signal supplied from the electromagnetic sensor 2 for the period from the rising or falling edge of the pulse signal supplied from the period detection unit 3 to the next rising or falling edge, A process for obtaining the rotational speed of a rotating body (not shown) is performed. Since this rotational speed recognition processing is the same as the conventional method, its detailed description is omitted.
[0025]
As described above, since the control unit 4 does not perform two processes simultaneously in parallel as in the prior art, but only performs a single process, the processing capacity is smaller than in the prior art. An inexpensive one can be used. As a result, the equipment cost of the rotation detection device A can be reduced, which contributes to price reduction.
[0026]
In particular, in the above embodiment, when generating a rectangular pulse signal for detecting the period of one rotation of the rotator, the large window 11B is provided in the required angle range of the pulsar ring 1 and is output from the electromagnetic sensor 2. Since the waveform amplitude of the electric signal is changed and there is no need to provide extra projections or separate extra parts on the pulsar ring 1, there is no waste.
[0027]
By the way, the rotation detection device A described above is used as, for example, rotation information input means in an ABS (anti-lock brake system) of an automobile, and specifically, as shown in FIG. On the other hand, it is mounted on the shaft end and used to detect the rotational speed of a wheel (not shown).
[0028]
In the figure, B shows the whole axle hub unit, 6 is a double row angular contact ball bearing, 7 is a rotating shaft that also serves as one inner ring of the bearing 6, and 8 is attached to the shaft end of the rotating shaft 7. It is a nut that prevents the double-row angular contact ball bearing 6 from coming off. The rotating shaft 7 corresponds to the rotating body described in the claims.
[0029]
The double-row angular ball bearing 6 includes an inner ring 61 having a single raceway groove and a single outer ring 62 having two rows of raceway grooves, and a plurality of rows arranged in two rows. It consists of a ball 63 and two crown-shaped cages 64 and 65. The outer ring 62 is non-rotatably fixed to an axle case (not shown) or the like via a radially outward flange 66 integrally formed on the outer periphery thereof. A wheel (not shown) is attached to the rotary shaft 7 via a radially outward flange 71 formed integrally with the shaft end.
[0030]
The pulsar ring 1 of the rotation detecting device A is press-fitted to the shoulder on the outer peripheral surface of one inner ring 61. Further, a bottomed cylindrical lid 9 is attached to the inner peripheral surface shoulder of the outer ring 62, and the electromagnetic sensor 2 of the rotation detection device A is attached to the inner wall surface of the lid 9 via the mold resin 10. It has been. In this state, the outer periphery of the annular yoke 21 of the electromagnetic sensor 2 is arranged to face the inner periphery of the pulsar ring 1 via a required gap.
[0031]
In addition, this invention is not limited only to embodiment mentioned above, Various application and deformation | transformation can be considered.
[0032]
(1) Although the large window 11B is provided in the required angle region of the pulsar ring 1 in the above embodiment, for example, the large window 11B may not be provided in the required angle region and the window may be omitted.
[0033]
(2) Although the multi-pole type electromagnetic sensor 2 is used in the above-described embodiment, an example using a pole-type electromagnetic sensor will be described below as an embodiment of a reference example. Although this monopole type electromagnetic sensor is not shown , the monopole type electromagnetic sensor does not have an annular shape as in the above-described embodiment, but has a size corresponding to one of the convex teeth 26 of the annular yoke 21 and is pulsar ring. It is arranged at one place on the circumference of one. In this case, for example, an electric signal having a waveform as shown in FIG. 6A is output from the electromagnetic sensor, and an envelope waveform as shown in FIG. 6B is output by the envelope detection circuit 31 of the period detector 3. And a rectangular pulse signal as shown in FIG. In this embodiment, the same operation and effect as in the above embodiment can be obtained.
[0034]
(3) In the above embodiment, an example using one set of pulsar ring 1 and electromagnetic sensor 2 is given. For example, as shown in Japanese Patent Application No. 8-193226 proposed by the present applicant, the radial direction The present invention can also be applied to a configuration in which two sets of pulsar rings 1 and electromagnetic sensors 2 are disposed inside and outside. In this case, a large window 11B as in the above embodiment may be provided for each pulsar ring 1, 1, or a windowless area may be provided as in (1) above.
[0035]
【The invention's effect】
In the rotation detection device according to the first and second aspects of the present invention, since the control unit does not perform two processes in parallel as in the prior art, only a single process is performed. This makes it possible to reduce the burden on the control unit and to use an inexpensive control unit with a relatively small processing capability. As a result, the equipment cost of the rotation detection device can be reduced, which contributes to a reduction in price.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a portable rotation detection device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing a part of an electromagnetic sensor and pulsar ring in FIG. FIG. 4 is a conceptual diagram showing an induced voltage waveform corresponding to the magnetic force intensity at each convex tooth of the annular yoke of the electromagnetic sensor shown in FIG. 2. FIG. 5 is a diagram showing the rotation detecting device of FIG. Fig. 6 is a longitudinal sectional view showing a hub unit for an automobile axle. Fig. 6 is a rotation detection device according to an embodiment of a reference example of the present invention.
A rotation detector
1 Pulsaring
Small window of 11A pulsar ring
11B Pulsaring large window
2 Electromagnetic sensor
21 annular yoke
22 Permanent magnet
23 Detection coil
26 Convex teeth of annular yoke
3 Period detector
31 Envelope detection circuit of period detector
32 Reference voltage generation circuit of period detector
33 Comparator of period detector
4 Control unit

Claims (1)

A pulsar ring fixed to the rotating body and provided with a plurality of windows at equal intervals around the circumference except for the circumferential required angle region;
An electromagnetic sensor that is fixed to the non-rotating member in a state of being opposed to the pulsar ring in a non-contact manner and outputs a magnetic force change as an electric signal according to a relative position with the pulsar ring
A period detector for detecting the period of one rotation of the rotating body based on the output of the electromagnetic sensor;
In the rotation detection device including the control unit that recognizes the rotation speed of the rotating body based on the output from the cycle detection unit and the output of the electromagnetic sensor,
The electromagnetic sensor is disposed to be opposed to the pulsar ring on the inner peripheral side with a required interval, and includes an annular yoke made of a magnetic material, an annular permanent magnet, and a detection coil wound around the annular yoke. The outer periphery of the annular yoke is opposed to the plurality of pulsar ring windows at equal circumferential intervals, and a plurality of convex teeth having a manufacturing shape error are formed.
In the required angle region of the pulsar ring, a window having an opening larger than the opening of the window provided in the other region is provided,
The period detector includes an envelope detector for detecting an output signal from a detection coil of the electromagnetic sensor, and a pulse for generating a rectangular pulse signal based on an output of the envelope detector and a required reference value A rotation detection device comprising: signal generation means;

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