JP2005249492A - Pulse generation device, and relative motion detector and bearing device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulse generation device which achieves high-power and is durable. <P>SOLUTION: A pulse generation device comprises a pulser 9 and a detection part 10 both of which face each other. A pulse generation part 12 is formed on a second plane 9b of the pulser 9. The pulse generation part 12 comprises convex parts 12a and concave parts 12b each of which is placed alternatively to form a corrugation part in cycles. At least the pulse generation part 12 of the pulser 9 is made from rubber or resins including a conductive material. When the pulser 9 and the detection part 10 perform relative movement, air gap between the pulse generation part 12 and the detection part 10 varies periodically, and the detection part 10 (electrostatic capacitance type sensor) outputs analog pulse signals A. A signal processing part 8 converts the analog pulse signals A to digital signals B with a binarization process, and outputs the digital signals to an ECU 18 (electronic control unit) as rotational speed detection signals. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pulse generator, a relative motion detector including the pulse generator, and a bearing device.

2. Description of the Related Art Conventionally, a multipolar magnetization type pulsar ring in which N poles and S poles are alternately arranged has been used as a rotational speed detection device for automobiles (see, for example, Patent Document 1).
Moreover, as a pulsar ring, there is a cylindrical plate made of a magnetic material in which a plurality of rectangular punched holes are formed in a uniform circumference (see, for example, Patent Document 2).
Furthermore, a bearing unit is provided that includes an outer ring member to which a pulsar ring is attached and an inner ring member to which a detection unit for detecting rotational speed is attached (see, for example, Patent Document 3).
JP 2001-249141 A JP 2000-2712 A Japanese Utility Model Publication No. 5-94722

However, since the above pulsar ring is made of metal or ferrite rubber composite, etc., it is difficult to process, and it is easy to chip due to collision with other members. Sex is reduced.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a highly reliable pulse generator, a relative motion detector including the same, and a bearing device that can achieve high output. .

In order to achieve the above object, the present invention comprises a pulse generator and a detection unit disposed opposite to the pulser, wherein the pulser generates a pulse according to the relative movement of the pulser and the detection unit. A pulse generation unit formed of a material including the pulse generation unit is provided, and the pulse generation unit includes a undulation portion that repeats periodically.
The inventor of the present application has come up with the present invention by paying attention to the conductivity of the conductive material. That is, assuming that ferrite is used as a magnetizing material (using a ferrite rubber composite), the content of the magnetizing material needs to be 80 to 98% by mass in order to obtain a sufficient pulse signal. On the other hand, in the case of a conductive material, a change in the distance between the undulating part relative to the detecting part can be easily detected based on, for example, a change in magnetic flux, and a sufficiently high pulse output can be achieved even with a relatively low addition amount. Can be obtained. Since the output is high, the distance between the pulser and the detection unit can be further increased, and the degree of layout freedom can be increased. Further, in the case of a conventional metal pulsar ring, it is difficult to process or magnetize with high precision. For example, the width per one pole in the circumferential direction of the ring is at least about 2 mm. The increase in number is also difficult. Further, when the pole width is reduced, the machining accumulated error increases. Further, there is a problem that breakage such as chipping is likely to occur. On the other hand, in the present invention, for example, a small amount of conductive material may be added to a material such as rubber or resin, and the moldability of these rubber or resin is hardly deteriorated. Small products can be manufactured easily and are inexpensive. In other words, it is possible to process rubber materials and the like almost to the limit of molding, and it is possible to form grooves with a width of several tens of μm, and the number of pulse signals of the pulsar can be greatly increased. Greatly improved. Furthermore, since the moldability hardly deteriorates, a rubber material or the like can be formed thin. In addition, since it is difficult to cause breakage such as chipping, the reliability is high. Further, the conventional ferrite rubber composite tends to wear the kneading equipment due to the hardness of the ferrite when kneaded. Further, in the conventional metal ring, when the magnetization width is reduced in order to increase the number of poles, the wear of the magnetization head becomes severe or the error in the magnetization width becomes large. On the other hand, in the case of rubber or resin to which a conductive material is added, there is no such problem.

  An example of the conductive material is a conductive filler. Specifically, carbon black and graphite can be exemplified. Also, fine particles of metals such as copper, copper alloy, silver and nickel, fine particles of low melting point alloys such as solder, fine particles of metal oxides such as zinc oxide, tin oxide and indium oxide, polypyrrole, polythiophene and polyaniline Examples thereof include fine particles of conductive polymer, fine particles of polymer coated with metal, fine particles of copper and silver coated with noble metal, metal fibers, and carbon fibers.

  In the present invention, the base material of the pulse generator may include rubber or resin. In this case, a conductive material is added to the base material, and the pulse generating portion can be formed by a mold, which makes manufacturing very easy. The minimum value of the width of one pole is determined by the minimum value of mold forming and the moldability of a rubber material or the like, and is about several tens of μm. Moreover, if it is rubber | gum and resin, it will not cause damage, such as a chip | tip, but can improve reliability.

In addition, the present invention includes the above-described pulse generator, and a signal processor that processes a signal from the detector of the pulse generator to obtain information related to the relative motion of the pulser and the detector. A motion detection device is provided. In this case, a sensor device such as a high-output displacement sensor, speed sensor, or acceleration sensor using a conductive material can be realized.
Further, the present invention is a bearing device including an inner ring, an outer ring, and the pulse generator described above, wherein the pulse generator of the pulse generator includes an annular pulser, and the pulser is fixed to either the inner ring or the outer ring. In addition, a bearing device is provided in which a detection unit is fixed to the other. In the present invention, a high pulse output can be obtained by incorporating the pulse generator into the bearing.

  In the present invention, an annular oil seal for sealing between the inner ring and the outer ring is provided, and the oil seal includes a seal member including a rubber seal lip, and a pulse generator is formed on the seal member. There is a case. In this case, the pulse generator and the oil seal can be used together, and the structure can be simplified.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of a bearing device to which a pulse generator according to a position embodiment of the present invention is applied. Referring to FIG. 1, the bearing device 1 includes a bearing 2 and a relative motion detection device 3. The bearing 2 includes, for example, an outer ring 4 as a fixed ring, an inner ring 5 as a rotating ring, and a plurality of rolling elements 6 disposed between the outer ring 4 and the inner ring 5. Although not shown, for example, the outer ring 4 is attached to a housing as a vehicle body side member of an automobile, and the inner ring 5 is attached to a rotating wheel as a wheel side member.

The relative motion detection device 3 includes a pulse generator 7 and a signal processing unit 8. The pulse generator 7 includes a pulsar 9 fixed to the inner ring 5 and a detection unit 10 disposed so as to oppose the pulsar 9 and the bearing 2 in the axial direction P. A pulse is generated according to (relative rotational motion).
The signal processing unit 8 processes a signal from the detection unit 10 of the pulse generator 7 to obtain information related to the rotational speed, for example, as information related to the relative motion between the pulser 9 and the detection unit 10. In this case, the relative motion detection device 3 functions as a speed sensor device.

The pulsar 9 is fixed to a support member 11 having an L-shaped cross section that is fitted and fixed to the outer periphery of the end portion of the inner ring 5. The pulsar 9 is formed of a circular annular plate, and the first surface 9 a is fixed along the support member 11. In addition, a pulse generation unit 12 is provided on the second surface 9 b of the pulsar body 9.
On the other hand, a support member 13 for supporting the detection unit 10 and the signal processing unit 8 is fixed to the outer periphery of the end portion of the outer ring 4. The support member 13 is composed of a short cylindrical outer peripheral wall 14 and an inner peripheral wall 15 and a flange 16 that connects these opposing ends, and has an annular shape as a whole, and the hollow section has a substantially U-shaped cross section. Eggplant. The detection unit 10 and the signal processing unit 8 are molded with a resin 17 in the hollow portion. The free end portion of the outer peripheral wall 14 extends longer than the inner peripheral wall 15 and is fixed to the outer periphery of the outer ring 4.

Referring to FIG. 3 which is a cross-sectional view taken along line III-III in FIG. 2 and FIG. 2, the annular pulse generators 12 are alternately arranged along the circumferential direction C as undulating portions that repeat periodically. Convex portion 12a and concave portion 12b.
At least the pulse generator 12 of the pulsar 9 is formed of a material including a conductive material. That is, as shown in FIG. 3, the entire pulsar 9 may be formed of a material containing a conductive material, or only the pulse generator 12 is formed of a material containing a conductive material as shown in FIG. 90 may be fixed to one surface. The pulse generator 12 or the pulsar 9 is obtained by adding a conductive material to rubber or resin as a base material. For example, the pulsar 9 is formed of a material including at least a part of the pulse generator 12 including a conductive polymer material.

  An example of the conductive material is a conductive filler. Specifically, carbon black and graphite can be exemplified. Also, fine particles of metals such as copper, copper alloy, silver and nickel, fine particles of low melting point alloys such as solder, fine particles of metal oxides such as zinc oxide, tin oxide and indium oxide, polypyrrole, polythiophene and polyaniline Examples thereof include fine particles of conductive polymer, fine particles of polymer coated with metal, fine particles of copper and silver coated with noble metal, metal fibers, and carbon fibers.

As the detection unit 10, various magnetoelectric conversion elements such as an eddy current sensor and a capacitance sensor can be used.
When the inner ring 5 and the pulsar 9 rotate with the rotation of the wheel, the air gap between the pulse generator 12 and the detector 10 in which the convex portions 12a and the concave portions 12b are alternately formed changes periodically. Along with this, since the magnetic flux, capacitance, etc. passing through the detection unit 10 periodically change, the magnetoelectric conversion element of the detection unit 10 outputs an analog electric signal corresponding to the change in pulses.

The signal processing unit 8 binarizes the analog pulse signal A obtained from the detection unit 10 and converts it into a digital signal B, which is output to a vehicle ECU (electronic control unit) 18 as a rotational speed detection signal. To do.
As described above, according to the present embodiment, a change in the distance between the convex portion 12a and the concave portion 12b relative to the detection unit 10 can be easily detected based on, for example, a magnetic flux change, and the pulser Even when the amount of the conductive material 9 is relatively low, a sufficiently high pulse output can be obtained.

  Also, in the case of conventional pulsar rings made of metal or ferrite rubber composites, it is difficult to process or magnetize accurately, and it is easy to cause breakage such as chipping and is not reliable. However, in this embodiment, a relatively small amount of a conductive material is added to the base rubber or resin, and the entire pulse generator 12 or pulsar 9 can be formed by a mold. Is very easy and inexpensive.

Further, with respect to the convex portion 12a and the concave portion 12b, it is possible to process rubber material or the like almost to the molding limit, and it is possible to form a groove with a width of several tens of μm, which can greatly increase the number of pulse signals of the pulser. The accuracy of detecting relative motion, etc., is greatly improved.
Further, a relatively small amount of conductive material may be added to a material such as rubber or resin, and the moldability of these rubber or resin is hardly deteriorated, so that the rubber or resin can be formed thin. Moreover, if it is rubber | gum and resin, it is hard to raise | generate breakage, such as a chip | tip, and can improve reliability.

Further, the rotation speed as the relative motion between the pulser 9 and the detection unit 10 can be easily detected by the convex portion 12 a and the concave portion 12 b of the pulse generation unit 12. Since the outputs as the pulse generator 7 and the relative motion detector 3 are high, the distance between the pulser 9 and the detector 10 can be increased, and the degree of freedom in layout can be increased.
In the above embodiment, the speed sensor device is realized as the relative motion detection device 3 to which the pulse generator 7 is applied. However, the present invention is not limited to this, and the displacement and acceleration are detected using the digital signal B described above. Also good. Also in this case, a high-output displacement sensor or acceleration sensor using the conductive material can be realized.

  Moreover, in the said embodiment, although the pulsar 9 and the detection part 10 were made to oppose the axial direction of the bearing 2, as shown in FIG. 5, the pulsar 900 fixed to the inner ring | wheel 5 with the supporting member 11A in the bearing apparatus 1A. Further, the detection unit 10 fixed to the outer ring 4 by the support member 13A may be opposed to the radial direction R of the bearing 2A. In this case, as shown in FIG. 6, the pulse generator 12 is formed on the outer peripheral surface of the annular pulsar 900.

In each of the above embodiments, the pulsar 9 or 900 is attached to the inner ring 5 and the detection unit 10 is attached to the outer ring 4. However, the pulsar 9 or 900 is attached to the outer ring 4 and the detection unit 10 is attached to the outer ring 5. Also good.
Further, the pulse generator 7 and the relative motion detector 3 can be incorporated not only in a rotary bearing but also in a linear bearing that moves linearly. In this case, the pulsar 9 is not annular but linear.

Further, the pulse generator 7 is not limited to the bearing device, and can be used as a device that outputs a pulse based on a motion between a pair of members that perform a rotational motion or a linear motion. Similarly, the relative motion detection device 3 can be used. Can be used not only as a bearing device but also as a sensor device that obtains information related to the motion between a pair of members that perform a rotational motion or a linear motion.
Further, as shown in FIG. 7, in an annular oil seal 20 applied to a bearing device, a pulse is applied to a rubber seal member 23 having seal lips 21 and 22 for sealing between the inner ring 5 and the inner ring 4. The generation unit 12 may be formed to configure the pulsar 9 and the detection unit 10 may be fixed to the slinger 24. In this case, the pulse generator and the oil seal can be used together, and the structure can be simplified. The seal member 23 is reinforced by a cored bar 25. The pulse generator 12 is preferably formed directly on the rubber seal member 23, but the pulse generator 12 provided separately may be attached to the seal member 23.

Further, as shown in FIG. 8, an annular recess 26 is formed on the outer surface extending in the radial direction of the slinger 24 to accommodate the pulsar 9, and the detection unit 10 is disposed so as to face the pulsar 9 in the axial direction. May be. In this case, a conventional sealing member can be used as it is.
The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims.

Examples 1 and 2
Example 1 was prepared as a pulse generator comprising a pulser having a pulse generation unit formed of rubber containing graphite as a conductive material and a detection unit using a capacitance displacement sensor. In Example 1, the addition ratio of graphite is 27% by mass.
In addition, Example 2 was created as a pulse generation device including a pulser having a pulse generation unit formed of rubber containing carbon black as a conductive material and a detection unit using a capacitive displacement sensor. In Example 2, the addition ratio of carbon black is 16% by mass.

  For Examples 1 and 2, the distance between the pulsar and the detection unit (air gap) was set variously, and the pulsar and the detection unit were relatively moved to determine the change in the output voltage. The result shown in FIG. 9 was obtained. It was. This proved that a very high output can be obtained by adding only a small amount of conductive material, ie, 27% by mass of graphite in Example 1 and 16% by mass of carbon black in Example 2. .

It is a schematic sectional drawing of the principal part of the bearing apparatus to which the relative motion detection apparatus containing the pulse generator of one embodiment of this invention was applied. It is a top view of a pulsar. It is sectional drawing which follows the III-III line of FIG. It is sectional drawing of the pulsar of another embodiment of this invention. It is a schematic sectional drawing of the principal part of the bearing apparatus with which the relative motion detection apparatus containing the pulse generator of further another embodiment of this invention was applied. It is sectional drawing of the pulsar of embodiment of FIG. In another embodiment of this invention, it is a schematic sectional drawing of the oil seal which serves as a pulse generator. It is a schematic sectional drawing of the principal part of another implementation of this invention. It is a graph which shows the relationship between distance and output voltage in Example 1, 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A bearing apparatus 2,2A bearing 3 Relative motion detection apparatus 4 Outer ring 5 Inner ring 6 Rolling body 7 Pulse generator 8 Signal processing part 9,90,900 Pulsar 9a 1st surface 9b 2nd surface 10 Detection part 11, 11A Support member 12 Pulse generation part 12a Convex part (undulation part)
12b Concave part (undulation part)
13, 13A Support member 18 ECU
20 Oil seal 23 Seal member 24 Slinger A Analog pulse signal B Digital signal (Rotation speed detection signal)
C Circumferential direction R Radial direction

Claims (5)

In a pulse generator that includes a pulser and a detection unit disposed opposite to the pulser, and generates a pulse according to the relative movement of the pulser and the detection unit,
The pulse generator includes a pulse generation unit formed of a material including a conductive material, and the pulse generation unit includes a undulation portion that repeats periodically.   2. The pulse generator according to claim 1, wherein the base material of the pulse generation unit includes rubber or resin.   A relative comprising: the pulse generator according to claim 1; and a signal processing unit that processes a signal from a detection unit of the pulse generation device to obtain information related to a relative motion between the pulser and the detection unit. Motion detection device.   A bearing device comprising an inner ring, an outer ring, and the pulse generator according to claim 1, wherein the pulse generator of the pulse generator includes an annular pulser, and the pulser is fixed to either the inner ring or the outer ring. And a detection device is fixed to the other.   5. An annular oil seal for sealing between the inner ring and the outer ring according to claim 4, wherein the oil seal includes a seal member including a rubber seal lip, and a pulse generator is formed on the seal member. A bearing device characterized by that.

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