JP2005308559A - Pulsar ring for magnetic rotary encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulsar ring for a magnetic rotary encoder manufacturable at low cost, having high accuracy of a polarization pitch, and capable of confirming easily the position of a polarized part. <P>SOLUTION: A pulsar body 142 comprising a material formed by mixing magnetic powder with a rubbery elastic material or a synthetic resin material and magnetized uniformly on the whole periphery by a unidirectional magnetic field is provided integrally with a ring holder 141 mounted on a rotator. The pulsar body 142 has many ribs 142a to be detected arranged at prescribed phase intervals. Since a magnetic pattern corresponds to the phase intervals of the ribs 142a to be detected, the magnetic pattern can be easily confirmed visually. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pulsar ring which is a detected body of a magnetic rotary encoder.

In an automobile anti-lock brake system (ABS), rotation detection of front and rear wheels is performed. And since such a rotation detection location is also a location that needs to be sealed, conventionally, as disclosed in, for example, Patent Document 1 below, the rotation side sealing of a sealing device that seals the shaft circumference of the rotating body is known. It is known that a pulsar ring, which is a detected element of a magnetic rotary encoder, is integrally provided on the element so that the rotary encoder and the sealing device can be installed in a small space.
JP 2002-48247 A

  FIG. 10 is a cross-sectional view showing an example of such a conventional sealing device having a pulsar ring, cut along a plane passing through the axis, and FIG. 11 is a cross-sectional perspective view showing the pulsar ring in the sealing device of FIG. is there. That is, the sealing device 100 shown in FIG. 10 includes a side lip 102 and a radial lip 103 that are fixed to a non-rotating outer ring 111 of a bearing, for example, in a wheel suspension device of an automobile via a metal ring 101, and an inner ring that is a rotating side. 112 and a pulsar ring 104 attached to 112. The pulsar ring 104 includes a slinger 104a that is slidably sealingly contacted with the side lip 102 and the radial lip 103, and a pulsar main body 104b that is integrally bonded to the outer surface thereof. In addition, a magnetic sensor 105 is disposed outside the pulsar ring 104 so as to face and face the pulsar main body 104b.

  The pulsar body 104b is formed in a flat disk shape with a rubber-like elastic material mixed with magnetic powder. As shown in FIG. 11, the N pole and the S pole are alternately magnetized in the circumferential direction. Yes. The pulsar ring 104 and the magnetic sensor 105 constitute a magnetic rotary encoder. When the pulsar ring 104 rotates together with the inner ring 112 shown in FIG. Through the N pole and S pole of the pulsar main body 104b alternately, the corresponding pulse signal P is output.

  Here, since the accuracy of the magnetization pitch of the N pole and S pole in the pulsar main body 104b affects the detection accuracy of the rotation angle, the accuracy of the magnetization pitch is as high as possible in order to improve the reliability of the rotary encoder. Need to be. For this reason, conventionally, the multi-pole magnetization of the pulsar body 104b has been performed by using a magnetizing equipment having a highly accurate multi-pole magnetizing head or a magnetizing equipment having a circumferentially-arranged magnetizing head. The equipment cost was high. In addition, confirmation of magnetization accuracy is impossible with a simple method such as visual observation, and it is necessary to use a magnetic property measuring instrument.

  Further, in the case of a magnetic rotary encoder mounted on the crankshaft for detecting the crank angle of the engine, for example, the top dead center of the piston at one place in the circumferential direction of the pulsar body 104b for the purpose of controlling the ignition timing of the engine. (TDC) or the like for detecting a specific position is provided with a position detection unit consisting of a non-magnetized part or a magnetized part with a different magnetization length in the radial direction. It was difficult. In addition, since such a position detection unit cannot be confirmed by visual observation, when incorporating it into the crankshaft, the crank angle that is the top dead center of the piston and the phase of the position detection unit are matched. In each case, it is necessary to check using a magnetic measuring instrument or the like, and problems such as complicated work have been pointed out.

  The present invention has been made in view of the above points, and its technical problem is that it can be manufactured at a low cost, has a high accuracy of the magnetization pitch, and confirms the position of the magnetized portion. An object is to provide an easy pulser ring for a magnetic rotary encoder.

  The technical problem described above can be effectively solved by the present invention. That is, the pulsar ring for a magnetic rotary encoder according to the first aspect of the present invention is a magnetized pulsar made of a material obtained by mixing a rubber-like elastic material or a synthetic resin material with magnetic powder in an annular holder mounted on a rotating body. The main body is integrally joined, and the pulsar main body has a large number of detection ribs arranged at a predetermined phase interval.

  A pulsar ring for a magnetic rotary encoder according to a second aspect of the present invention is the structure of the first aspect, wherein each of the detected ribs is partially continuous with each other in the circumferential direction.

  A pulsar ring for a magnetic rotary encoder according to a third aspect of the present invention is the pulsar ring according to the first aspect, wherein the pulsar main body is uniformly magnetized by a magnetic field in one direction.

  A pulsar ring for a magnetic rotary encoder according to a fourth aspect of the present invention is the structure according to any one of the first to third aspects, wherein the pulsar ring is located between the detected ribs and is filled with a nonmagnetic member, They are joined together.

  A pulsar ring for a magnetic rotary encoder according to a fifth aspect of the present invention is the magnetic rotary encoder according to the fourth aspect, wherein the nonmagnetic member is made of a material having a color different from that of the pulsar main body or a transparent material.

  According to the pulsar ring for a magnetic rotary encoder according to the first aspect of the present invention, the magnetic pattern corresponds to the pattern of the pulsar body, that is, the magnetization pitch corresponds to the phase interval of the detected rib. And the magnetic pattern can be easily confirmed by visual observation. Therefore, not only an assembling operation can be facilitated but also an assembling mistake can be prevented. In addition, by having a pattern in which the phase interval or radial length of the rib to be detected is different in one place in the circumferential direction, for example, it is possible to detect a specific position such as a top dead center of the piston, The pattern etc. which form can also be formed easily. Moreover, since the pulsar main body has a circumferentially divided shape, it is less susceptible to stress due to thermal expansion and contraction, and durability can be improved.

  According to the pulsar ring for a magnetic rotary encoder according to the second aspect of the present invention, since the detected ribs are continuous with each other in the circumferential direction on the inner peripheral side or the outer peripheral side, they are easily formed by injection molding or the like. Can do.

  According to the pulsar ring for a magnetic rotary encoder according to the third aspect of the present invention, the magnetic pattern corresponding to the pattern of the rib to be detected is written only by magnetizing the pulsar main body uniformly by the magnetic field in one direction. Therefore, there is no need for multipolar magnetization, and it can be manufactured at low cost.

  According to the pulsar ring for a magnetic rotary encoder according to the fourth aspect of the present invention, each detected rib is supported by the nonmagnetic member filled and joined on both sides thereof, so that the magnetization pitch due to the deformation of the detected rib , And hence a decrease in detection accuracy can be prevented.

  According to the pulsar ring for a magnetic rotary encoder according to the invention of claim 5, the nonmagnetic member of claim 4 is made of a material having a color different from that of the pulsar body or a transparent material. The pattern can be clearly identified visually, and therefore, as in the case of claim 1, not only the assembling work can be facilitated, but also an assembling mistake can be prevented.

  Hereinafter, preferred embodiments of a pulsar ring for a magnetic rotary encoder according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a half sectional view showing a mounting state in which a sealing device 1 including a pulsar ring 14 for a magnetic rotary encoder according to the present invention is cut along a plane passing through an axis, and FIG. 3 is a cross-sectional perspective view showing the pulsar ring 14 according to the embodiment, FIG. 3 is a cross-sectional view showing the pulsar ring 14 of FIG. 2 cut in a direction perpendicular to the extending direction of the detection rib 142a, and FIG. 4 is a pulsar of FIG. FIG. 6 is a diagram showing a magnetic pattern of a pulsar body 142 in a ring 14

  First, in FIG. 1, reference numeral 1 is a sealing device, reference numeral 2 is a rotating shaft, and reference numeral 3 is a non-rotating seal housing existing on the outer periphery of the rotating shaft 2. The rotating shaft 2 corresponds to the rotating body described in claim 1.

  The sealing device 1 includes a mounting ring 11 that is press-fitted into the seal housing 3, a side lip 12 and a radial lip 13 that are provided integrally with the mounting ring 11, and a pulser that is mounted on the outer peripheral surface of the rotary shaft 2. And a ring 14. A magnetic sensor 4 made of a magnetoresistive element is disposed on the atmosphere side of the sealing device 1 and is fixed to the seal housing 3 side.

  The mounting ring 11 is manufactured by punching and pressing a metal plate such as a steel plate. The side lip 12 and the radial lip 13 are formed of a rubber-like elastic material, and the base portion thereof is vulcanized to the mounting ring 11. It is glued. The pulsar ring 14 includes a slinger 141 and a pulsar main body 142 provided integrally with the slinger 141.

  The slinger 141 in the pulsar ring 14 corresponds to the annular holder described in claim 1, and is manufactured by punching and pressing a metal plate such as a steel plate, and a seal flange 141 a that expands into a disk shape. The sleeve portion 141b extends from the inner periphery to the machine inner side and is tightly fitted to the outer peripheral surface of the rotary shaft 2. The tip of the side lip 12 is slidably in contact with the inner surface of the seal flange 141a, and the tip of the radial lip 13 is slidably in contact with the outer peripheral surface of the sleeve 141b.

  The pulsar body 142 in the pulsar ring 14 is made of a material in which a magnetic powder such as ferrite is mixed with a rubber-like elastic material or a synthetic resin material. The outer surface of the seal flange 141a in the slinger 141 is formed by a closed molding method such as injection molding. In addition, they are integrally vulcanized and bonded simultaneously with molding. As shown in FIGS. 2 and 4, the pulsar main body 142 has a large number of detection ribs 142 a extending in the radial direction of the seal flange 141 a and formed at equal phase intervals, and inner peripheral ends thereof are continuous with each other. Thus, the annular portion 142b extending in the circumferential direction is formed, and between the detected ribs 142a and 142a adjacent in the circumferential direction is a notch portion 142c in which the seal flange 141a is exposed.

  The pulsar body 142 is uniformly magnetized all around by a unidirectional magnetic field. Therefore, as shown in FIG. 3, the detected ribs 142a are magnetized with the same polarity, that is, have magnetic fields in the same direction. The detection surface of the magnetic sensor 4 shown in FIG. 1 is close to the pulsar main body 142 in the pulsar ring 14 in the axial direction, and the pulsar ring 14 and the magnetic sensor 4 constitute a magnetic rotary encoder. ing.

  In the above configuration, the sealing device 1 shown in FIG. 1 has the entire circumference of the side lip 12 and the radial lip 13 attached to the inner circumference of the non-rotating seal housing 3 via the attachment ring 11 together with the rotary shaft 2. When the pulsar ring 14 of the rotating pulsar ring 14 is closely slid with the seal flange 141a and the sleeve portion 141b of the slinger 141, the sealing function is achieved.

  Further, since the pulsar ring 14 rotates integrally with the rotating shaft 2, the detected rib 142 a of the pulsar main body 142 sequentially passes in the circumferential direction in front of the detection surface of the magnetic sensor 4. Since the strength of the magnetic field of each detected rib 142a is distributed as shown by the broken line in FIG. 3, the magnetic sensor 4 generates a pulse signal P having a waveform corresponding to the change of the magnetic flux crossing this. . Therefore, the frequency of the pulse signal P output from the magnetic sensor 4 is proportional to the number of rotations of the rotary shaft 2, and the rotational speed and the rotation angle of the rotary shaft 2 are detected from this pulse train and used for various controls. be able to.

  In the pulsar ring 14 according to this embodiment, since the pulsar body 142 is magnetized uniformly by a magnetic field in one direction, the magnetic pattern corresponds to the shape pattern of the pulsar body 142. That is, as shown in FIG. 3, the magnetization pitch corresponds to the phase interval α of the detected rib 142 a, and as a result, depends on the machining accuracy of the mold for molding the pulsar body 142. For this reason, a magnetic pattern can be written with a simple unidirectional magnetic field magnetizer without using a high-precision multi-pole magnetic device or the like for alternately magnetizing different magnetic poles. Accuracy can be improved. In addition, since the magnetic pattern corresponds to the shape pattern of the pulsar main body 142 (detected rib 142a), this can be easily confirmed by visual observation, such as the alignment in the circumferential direction when incorporated into the rotating shaft 2, etc. This can be done easily, and mounting errors can be prevented.

  Further, as shown in FIG. 4, the pulsar main body 142 has a shape in which the detected rib 142a is elongated in the radial direction. Therefore, when the pulsar main body 142 is filled with uncured rubber material or synthetic resin material, Thus, the orientation of the magnetic powder in the material is easily obtained. For this reason, it is easy to perform uniform magnetization on the entire circumference, and as a result, a high-performance pulsar ring 14 with high magnetization accuracy can be obtained. Further, since the detected rib 142a has a circumferentially divided shape, the detected rib 142a is less susceptible to stress due to thermal expansion and contraction during use, and can improve toughness against hardening cracks and the like.

  Further, the side lip 12 and the radial lip 13 generate heat by being slid closely with the slinger 141. However, as in this embodiment, the seal flange 141a of the slinger 141 is exposed at the notch 142c of the pulsar main body 142. Therefore, heat is efficiently radiated through the seal flange 141a.

  Next, FIG. 5 is a cross-sectional perspective view showing the pulsar ring 14 according to the second embodiment of the present invention, and FIG. 6 shows the pulsar ring 14 of FIG. 5 cut in a direction perpendicular to the extending direction of the detection rib 142a. It is sectional drawing. The second embodiment is different from the first embodiment described above in that a nonmagnetic member 143 is filled between the detected ribs 142a and 142a. The nonmagnetic member 143 is made of, for example, a hard rubber-like elastic material or a synthetic resin material, and is formed so as to form a flat surface continuous with the pulsar main body 142. It is integrally joined to both sides in close contact.

  According to this configuration, the detection ribs 142a, 142a,... Formed in an elongated shape are supported by the nonmagnetic member 143 made of a hard rubber-like elastic material or synthetic resin material from both sides in the circumferential direction, and the strength is compensated. Is done. For this reason, the change of the magnetization pitch by deformation | transformation of to-be-detected rib 142a, 142a, ... can be prevented, and also the fall of a detection accuracy can be prevented.

  In this case, since the pulsar body 142 is a colored material mixed with magnetic powder, the nonmagnetic member 143 is preferably made of a rubber-like elastic material or a synthetic resin material that is transparent or has a different color from the pulsar body 142. . In this way, the shape pattern of the pulsar body 142 that is the magnetized portion can be clearly identified by visual observation. For this reason, the alignment of the circumferential direction at the time of incorporating in the rotating shaft 2 can be performed easily.

  Next, FIG. 7, FIG. 8 and FIG. 9 are explanatory views showing pulsar rings 14 having different patterns of the pulsar main body 142, respectively. Of these, the pulsar ring 14 shown in FIGS. 7 and 8 is a circular rotary encoder mounted on a crankshaft for detecting the crank angle of the engine, for example, for controlling the ignition timing of the engine. For example, a position detection unit 142d for detecting a specific position such as a top dead center (TDC) of the piston is provided at one place in the circumferential direction.

  Specifically, the position detection unit 142d in FIG. 7 is provided with a portion having a phase interval of 2α at one place in the circumferential direction with respect to the phase interval α of the equally spaced portion of the detected rib 142a in the pulsar body 142. The position detection unit 142c in FIG. 8 is provided with a detected rib 142a ′ for detecting a specific position whose radial direction length is increased toward the outer diameter side at one place in the circumferential direction, and the other detected ribs 142a are short and equally long. That's what it is. Further, in the example shown in FIG. 8, the rotational speed and rotation angle detection magnetic sensor 4A opposite to the rotation locus of the detected rib 142a and the detected rib 142a ′ on the outer peripheral side of the rotation locus of the detected rib 142a. And a magnetic sensor 4B for detecting a specific position such as TDC facing the rotation trajectory of the outer diameter portion.

  According to the present invention, such a position detector 142d can also be provided with high positional accuracy due to the processing accuracy of the mold for molding the pulsar body 142. Further, the position of the position detector 142d can be easily confirmed visually by the difference in pattern from other parts. For this reason, when the pulsar ring 14 is incorporated into the rotary shaft 2, the top dead center of the piston is obtained. As a result, the crank angle and the position detection unit 142d can be easily aligned with each other by visual observation, so that not only an assembling operation can be facilitated but also an assembling mistake can be prevented.

  In addition to the forms shown in FIGS. 7 and 8, other means such as changing the width and number of the ribs 142a to be detected at one place in the circumferential direction can be adopted as the position detection unit 142d.

  Further, the pulsar ring 14 shown in FIG. 9 has a pulsar body 142 that forms a multitrack formed along a plurality of concentric circumferences. Specifically, the pulsar main body 142 has an inner peripheral track T1 that is unevenly provided on the inner peripheral side of the seal flange 141a of the slinger 141, and an outer peripheral track T2 that is provided unevenly on the outer peripheral side of the seal flange 141a. On the outside of the pulsar ring 14, a magnetic sensor 4C facing the inner track T1 and a magnetic sensor 4D facing the outer track T2 are arranged.

  The inner peripheral track T1 is composed of a large number of detected ribs 142e extending in the radial direction and the inner peripheral ends are continuous with each other via an annular portion 142b. The outer peripheral track T2 is a large number of detected ribs 142f extending in the radial direction. Consists of. The detected rib 142e of the inner track T1 and the detected rib 142f of the outer track T2 are formed with the same phase interval α and different phases by an angle β smaller than α, and the detected rib 142e of the inner track T1 is detected. The outer peripheral end portion of the rib 142e and the inner peripheral end portion of the detected rib 142f of the outer peripheral track T2 are partially connected to each other.

  That is, according to the pulsar ring 14 shown in FIG. 9, the phase difference β is generated in the output waveforms from the magnetic sensor 4C and the magnetic sensor 4D due to the phase difference β between the detected ribs 142e and 142f. The rotation direction can also be detected.

  Since the outer peripheral end of the detected rib 142e and the inner peripheral end of the detected rib 142f are connected to each other, in the manufacture of the pulsar ring 14, the molding material is filled from the annular portion 142b side during molding. Thus, since the molding material is shaped from the inner peripheral side to all the detection ribs 142e and 142f, such a magnetic pattern can be formed easily and with high accuracy.

  In the pulsar ring 14 shown in FIG. 9, the detected ribs 142e of the inner track T1 and the detected ribs 142f of the outer track T2 are the same number (the same phase interval α), but different phase intervals (different numbers). ), It is possible to set different resolutions. 7, 8, and 9, as in FIGS. 5 and 6, a transparent rubber or a hard rubber-like elastic material or synthetic resin material having a different color is used between the detected ribs. A structure in which the magnetic member 143 is filled and integrally joined can be obtained.

  Further, the present invention can be similarly applied to a pulsar ring that is not integrated with the sealing device 1 as shown in FIG. 1, that is, a pulsar ring in which the holder does not constitute the rotary side sealing element of the sealing device. The present invention can also be applied to a case where a pulsar ring (detected rib) is formed on the outer peripheral surface of a cylindrical holder.

1 is a half sectional view of a mounting state in which a sealing device including a pulsar ring for a magnetic rotary encoder according to the present invention is cut along a plane passing through an axis. It is a section perspective view showing the 1st form of the pulsar ring for magnetic rotary encoders concerning the present invention. It is sectional drawing which cut | disconnects and shows the pulsar ring of FIG. 2 in the direction orthogonal to the extension direction of a to-be-detected rib. It is explanatory drawing which shows the magnetic pattern of the pulsar main body in the pulsar ring of FIG. It is a cross-sectional perspective view which shows the 2nd form of the pulsar ring for magnetic rotary encoders which concerns on this invention. It is sectional drawing which cut | disconnects and shows the pulsar ring of FIG. 5 in the direction orthogonal to the extension direction of a to-be-detected rib. It is explanatory drawing which shows the example from which the pattern of the pulsar main body in a pulsar ring differs. It is explanatory drawing which shows the other example from which the pattern of the pulsar main body in a pulsar ring differs. It is explanatory drawing which shows the other example from which the pattern of the pulsar main body in a pulsar ring differs. It is sectional drawing which cuts and shows an example of the sealing device which has a pulsar ring of a conventional structure by the plane which passes along an axial center. It is a cross-sectional perspective view which shows the pulsar ring in the sealing device of FIG.

Explanation of symbols

1 Sealing device 14 Pulsar ring 141 Slinger (annular holder)
141a Seal flange 141b Sleeve part 142 Pulsar body 142a, 142a ', 142e, 142f Detected rib 142b Inner peripheral part 142c Notch part 142d Position detection part 143 Nonmagnetic member 2 Rotating shaft (rotating body)
3 Seal housing 4, 4A-4D Magnetic sensor

Claims (5)

  A magnetized pulsar body (142) made of a material obtained by mixing a magnetic powder with a rubber-like elastic material or a synthetic resin material is integrally joined to an annular holder (141) attached to the rotating body (2). A pulsar ring for a magnetic rotary encoder, wherein the pulsar body (142) has a large number of detected ribs (142a, 142a ′, 142e, 142f) arranged at a predetermined phase interval (α).   2. The pulsar ring for a magnetic rotary encoder according to claim 1, wherein the detected ribs (142a, 142a ', 142e, 142f) are partially continuous with each other in the circumferential direction.   The pulsar ring for a magnetic rotary encoder according to claim 1, wherein the pulsar body (142) is uniformly magnetized all around by a magnetic field in one direction.   The non-magnetic member (143) is filled between the detected ribs (142a, 142a ', 142e, 142f) and integrally joined to the holder (141). The pulser ring for magnetic rotary encoders in any one of -3.   The pulsar ring for a magnetic rotary encoder according to claim 4, wherein the nonmagnetic member (143) is made of a material having a color different from that of the pulsar body (142) or a transparent material.

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