JPH04276557A - Magnetic rotation sensor - Google Patents

Abstract

PURPOSE:To achieve the cost reduction of a magnetic rotation sensor and to improve output accuracy and durability. CONSTITUTION:A rotary member 10 is provided. Two facing multipole magnetized surfaces 11 and 12 are attached to the inner surfaces of both end parts of a rotary member in the axial direction at the outside of the direction of the diameter. Each magnetized surface is divided into equal regions in the radial direction of the diameter. The neighboring regions are magnetized in the different polarities. A magnetism detecting sensor 40 is arranged between the multipole magnetized surfaces 11 and 12. The magnetism detecting sensor 40 is coated with a resin mold 60. An attaching member 13 for attachment to a vehicle body and the like is attached.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational speed detection device for detecting the rotational speed of a rotating body.

0002

2. Description of the Related Art Conventional magnetic rotation sensors include those shown in FIGS. 8, 9, and 10, for example. (Japanese Unexamined Patent Publication No. 64-6763) FIG. 8 is a partial perspective view of a conventional magnetic rotation sensor, and FIGS. 9 and 10 are sectional views for explaining the operation.

In FIG. 8, 1 is a rotating member, 80 is a magnetic field generating member, and 3 is a magnetic sensor. Reference numeral 8 denotes a rotating shaft, and the rotating shaft 8 is concentric with the rotating member 1 and extends through the rotating member 1. At both axial end portions of the outer circumferential surface of the rotating member 1, there are two protrusions 4 and 5 for detecting rotational speed that protrude radially outward in the radial direction along the outer circumferential edge.
Lines are formed. The rotating member 1 and the projecting pieces 4 and 5 are made of magnetic material. The magnetic field generating member 80 is formed into a substantially U-shape, and includes a first arm portion 81 and a second arm portion 82.
Each free end is provided with convex portions 83 and 84 that protrude in directions facing each other. One of the protrusions 83 is magnetized to the north pole, and the other protrusion 84 is magnetized to the south pole. The magnetic field generating member 80 is disposed radially outward of the rotating member 1, and the two protrusions 4 and 5 of the rotating member 1 are sandwiched between the first arm 81 and the second arm 82, and the magnetic sensor 3
is placed between the projecting pieces 4 and 5. Both arms 8
The convex portions 83 and 84 of Nos. 1 and 82 and the respective protrusions 4 and 5 are disposed at a predetermined distance apart from each other in a non-contact state. The magnetic sensor 3 is attached to the magnetic field generating member 80 and placed in the center between both convex portions 83 and 84, and faces the protrusions 4 and 5 of the rotating member 1 in a non-contact state. The magnetic sensor 3 is, for example, a coil, and outputs a pulse signal in response to changes in the density of magnetic flux passing through the magnetic sensor 3.

Next, the operation will be explained. As shown in FIG. 9, when the concave portions between the protruding pieces 4 and the concave portions between the protruding pieces 5 face the convex portions 83 and 84, the N of the convex portion 83 is
Magnetic flux flows from the pole face as shown by arrows 51 and 52,
Most of the magnetic flux is directed to the magnetic sensor 3 as shown by the arrow 51 in the figure.
The magnetic sensor 3 enters the S pole surface of the protrusion 84 through
A voltage is applied in a direction that cancels out the increased magnetic flux indicated by the arrow 51, and this is output.

On the other hand, as shown in FIG. 10, when the projections 4 and 5 are opposed to the projections 83 and 84,
Magnetic flux flows from the N-pole surface as shown by arrows 53 and 54 in the figure, but most of the magnetic flux flows inside protrusions 4 and 5 as indicated by arrow 5.
4, the magnetic flux passes through and enters the S pole face of the convex portion 84, so that almost no magnetic flux passes through the magnetic sensor 3, and therefore the magnetic sensor 3 outputs almost no voltage.

[0006] As described above, as the rotating member 1 rotates, the magnetic flux density passing through the magnetic sensor 3 changes, and the period of the pulse output from the magnetic sensor 3 changes in proportion to the change in magnetic flux density. , the rotational speed of the rotating member 1 can be sensed by determining this period.

[0007]

[Problems to be Solved by the Invention] However, in such a conventional magnetic rotation sensor, the opposing detection portions of the rotating member have a two-row gear-like configuration.
Machining of rotating members is complicated and costs are high. Furthermore, if the magnetic sensor is used in the wheel of a car, the magnetic sensor is exposed, so if mud or the like gets clogged between the protrusions of the rotating member, the magnetic sensor may be destroyed. Ta. In addition, since the structure was such that high output could not be obtained unless the magnetic field generating member and rotating member were arranged vertically, there was a problem that the output would decrease unless the magnetic field generating member was installed vertically and with high precision. There was a point.

The object of the present invention is to reduce the cost and improve the output accuracy and durability of a magnetic rotation sensor.

[0009]

[Means for Solving the Problems] The present invention includes a cylindrical rotating shaft, a rotating member through which the rotating shaft concentrically extends, a fixed member that rotatably supports the rotating shaft, and a rotating member that rotatably supports the rotating shaft. A ring-shaped first ring-shaped first magnet which is divided into regions radially from the center of the member, adjacent regions are magnetized to have opposite polarities, is provided on the rotating member, and rotates integrally with the rotating member. a multipolar magnetized member;
a ring-shaped second multi-pole magnet, which is provided on the rotating member so as to face the first multi-pole magnetized member so that the opposing region has an opposite polarity, and rotates integrally with the rotating member; The magnetic member is covered with resin and fixed to the fixed member between the magnetic member and the first and second multi-pole magnetized members, and the first and second
A magnetic detection sensor detects the magnetic field generated by the multi-polar magnetized member.

0010

[Operation] With the above configuration, the direction of the magnetic flux between the first and second multipolar magnetized members changes as the rotating member to which the multipolar magnetized member is attached changes, so the magnetic flux changes. is detected by a magnetic detection sensor. Since the output of the magnetic detection sensor also changes in proportion to the change in magnetic flux, the rotational speed of the rotating member is calculated by measuring the period of the output.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings.

FIG. 1 is a diagram showing a first embodiment of the present invention.

First, the configuration will be explained. Reference numeral 9 denotes a cylindrical rotating shaft, and the rotating shaft 9 extends through a rotating member 10 that is concentric with the rotating shaft 9. Reference numeral 13 denotes a mounting member to which the rotating shaft 9 is rotatably mounted. In this embodiment, illustrations of the mounting portions of the rotating shaft 9 and the mounting member 13 are omitted. Two ring-shaped multipolar magnetized surfaces 11 and 12 are attached to opposing radially outer surfaces of both axial end portions of the rotating member 10. It is divided into regions by lines, and adjacent regions are magnetized to have opposite polarities. Furthermore, the two opposing multi-pole magnetized surfaces are also magnetized so that they have opposite polarities. Between the two multipolar magnetized surfaces 11 and 12, there are two opposing multipolar magnetized surfaces 11 and 1.
A magnetic detection sensor 40 is arranged to detect the magnetic flux density of the magnetic field generated by the magnet. In addition, the magnetic detection sensor 40
is covered with a resin mold 60, and is further attached and fixed to the vehicle body or a member assembled to the vehicle body via the attachment member 13. Therefore, the resin mold 60 and the magnetic detection sensor 40 do not move regardless of the rotation of the rotating member 10. FIG. 2 is a sectional view of the first embodiment. Reference numeral 9 denotes a cylindrical rotating shaft, which extends through a rotating member 10 that is concentric with the rotating shaft 9. The multipolar magnetized surfaces 11 and 12 are provided at both ends of the rotating member 10 in the axial direction, and the two multipolar magnetized surfaces 11 and 12 face each other in parallel. A magnetic detection sensor 40 is arranged between the multipolar magnetized surfaces 11 and 12, and the magnetic detection sensor 40 is covered with a resin mold. Here, the attachment member 13 attached to the magnetic detection sensor 40 molded with resin is omitted from illustration.

Next, the operation will be explained. FIG. 3 is an explanatory diagram of the action. However, the resin mold 60 and the mounting member 13 are omitted in the drawings. The magnetic detection sensor 40 disposed between the multipolar magnetized surface 11 and the multipolar magnetized surface 12 detects the magnetic flux flowing from the N pole of the multipolar magnetized surface 11 to the S pole of the multipolar magnetized surface 12. From the N pole of the polar magnetized surface 12 to the multi-pole magnetized surface 12
The magnetic flux directed toward the S pole of the multipolar magnetized surface 11 and the magnetic flux directed from the N pole of the multipolar magnetized surface 11 toward the S pole of the multipolar magnetized surface 11 are detected. The output detected at this time is assumed to be a positive output. When the rotating member 10 rotates by one pitch with respect to the magnetic detection sensor 40, the polarities magnetized on the multipolar magnetized surfaces 11 and 12 are reversed, so that the direction of the detected magnetic flux is also reversed. The output detected at this time is temporarily assumed to be a negative output. Rotating member 10
As the rotating member 10 rotates, positive outputs and negative outputs are output alternately, and the period of the positive and negative outputs detected by the magnetic detection sensor 40 changes in proportion to the change in rotation of the rotating member 10. By measuring the period of the positive and negative outputs, the rotational speed of the rotating member 10 can be determined.

In this embodiment, since the shape of the rotating member 10 can be made simple, the rotating member 10 can be easily processed, leading to cost reduction. Also,
Since the magnetic detection sensor 40 is molded with resin, the magnetic detection sensor 40 will not be destroyed by mud or the like.

Next, a second embodiment will be explained with reference to FIGS. 4 and 5. To explain the structure, 9 is a cylindrical rotating shaft, and is provided through a rotating member 20 that is concentric with the rotating shaft 9. Reference numeral 14 denotes a mounting member to which the rotating shaft 9 is rotatably mounted. In this embodiment, illustrations of the attachment portions of the rotating shaft 9 and the attachment member 14 are omitted. Multi-pole magnetized surfaces 21 and 22 are provided so as to protrude perpendicularly to one side surface of the rotating member 20, and are located on the outer peripheral edge of the rotating member 20 and its radial center side. It is provided in two locations, one at a position shifted from the other. Further, the multipolar magnetized surfaces 21 and 22 are adapted to move together with the rotating member 20. Multipolar magnetized surfaces 21 and 22 are rotary member 20
It is divided into equal regions radially in the axial direction, and adjacent regions are magnetized to have opposite polarities. Further, the multipolar magnetized surfaces 21 and 22 have their magnetized surfaces facing each other, and the opposing regions are respectively magnetized to have opposite polarities. A magnetic detection sensor 40 is arranged between the multipolar magnetized surfaces 21 and 22 to detect the magnetic flux density of the magnetic field generated by the multipolar magnetized surfaces 21 and 22.
This magnetic detection sensor 40 is covered with a resin mold 61, and is further attached and fixed to a mounting member 14 for mounting on a vehicle body or the like. Therefore, the resin mold 61 and the magnetic detection sensor 40 do not move regardless of the rotation of the rotating member 20. However, in FIG. 5, illustration of the mounting member 14 is omitted.

The operation is the same as that of the first embodiment, so a description thereof will be omitted. Further, as an effect of the second embodiment, the rotating member 2
When it is difficult to arrange the magnetic detection sensor 40 from the zero radial direction, there is an effect that it can be arranged from the axial direction. Further, since the rotating member 20 has a simple shape, the rotating member 20 can be easily processed, resulting in cost reduction. Furthermore, since the magnetic detection sensor 40 is molded with resin, it will not be destroyed by mud or the like.

Next, a third embodiment will be explained using FIG. 6. 30 is a rotating member formed to have a stepped portion as shown. 9 is a rotating shaft, and the rotating member 3
The rotary member 30 is provided concentrically with the rotary member 30 . Reference numeral 13 denotes a mounting member to which the rotating shaft 9 is rotatably mounted. In this embodiment, illustration of the rotating shaft 9 and the mounting member 13 is omitted. One of the two stepped parts of the rotating member 30 has a ring-shaped multipolar magnetized surface 31 and the rotating ring 16, and the other stepped part has a ring-shaped multipolar magnetized surface 32 and the rotating ring 1.
6 is press-fitted. In addition, multipolar magnetized surfaces 31 and 32
are mounted on the inner side with respect to the axial direction of the rotating member 30 so as to face each other. Further, the two multi-polar magnetized surfaces 31 and 32 are divided into equal regions radially in the radial direction of the rotating member 30, and adjacent regions are magnetized to have opposite polarities, and are further divided into opposing regions. The regions of the multipolar magnetized surfaces 31 and 32 also have opposite polarity. Between the two multipolar magnetized surfaces 31 and 32, there is a multipolar magnetized surface 31 and 32.
A magnetic detection sensor 40 is arranged to detect the magnetic flux density of the magnetic field generated by the magnetic field. In addition, the magnetic detection sensor 40
is covered with a resin mold 62, and furthermore, a mounting member 13 is attached and fixed in order to attach it to a vehicle body, but is not shown here. therefore,
The resin mold 62 and the magnetic detection sensor 40 are connected to the rotating member 30
The effect of not moving regardless of rotation is the same as in the first and second embodiments, so a description thereof will be omitted. Further, as an effect of this embodiment, the interval between the two multi-pole magnetized surfaces 31 and 32 can be easily changed by processing the rotating member 30, and the interval between the two multi-pole magnetized surfaces 31 and 32 can be changed easily. This changes the magnitude of the magnetic flux density detected by the magnetic detection sensor 40, so the output sensitivity can be easily varied. Moreover, since the magnetic detection sensor 40 is molded with resin, even if mud or the like gets stuck between the multipolar magnetized surfaces 31 and 32, the magnetic detection sensor 40 will not be destroyed.

Next, a fourth embodiment will be explained using FIG. 7. In the first, second and third embodiments, the magnetic detection sensor 4
0 was arranged in the radial direction of the rotating member 10 between the two multipolar magnetized surfaces 11 and 12, but in this embodiment, the rotating member 1
The magnetic detection sensor 40 is arranged on the outer periphery from the radial outer circumferential surface of 0, not in the center between the multipolar magnetized surfaces, but shifted from the center. Other configurations are the first
Since this is the same as the embodiment, the explanation will be omitted.

[0020] The operation is also the same as in other embodiments, so a description thereof will be omitted. Further, as an effect of this embodiment, the magnetic flux generated by the rotation of the multipolar magnetized surfaces 11 and 12, which are magnetized so that the polarities of adjacent regions are alternately opposite polarities and the opposing surfaces are opposite polarities. Since the change in direction is detected by the magnetic detection sensor 40, when it is difficult to arrange the magnetic detection sensor 40 in the center of the two multipolar magnetized surfaces 11 and 12, it is possible to arrange it offset from the center. . Further, since the magnetic detection sensor 40 is covered with resin, even if mud or the like gets stuck between the multipolar magnetized surfaces 11 and 12, the magnetic detection sensor 40 will not be destroyed.

[0021]

[Effect] In the present invention, the magnetic field generated by the first and second multipolar magnetized members is detected by the magnetic detection sensor disposed between the first and second multipolar magnetized members. , since the rotational speed is calculated, the rotating member is cylindrical,
Since the multi-pole magnetized member can be made into a simple ring shape without unevenness, processing of the rotating member and the multi-pole magnetized member is easy and costs are reduced. Furthermore, since the magnetic detection sensor is covered with resin, even if the detection portion becomes clogged with mud, the magnetic sensor will not be destroyed. Furthermore, in order to detect changes in the direction of magnetic flux between the first and second multi-pole magnetized members and calculate the rotational speed of the rotating member, the magnetic detection sensor does not have to be arranged with high precision to achieve the desired result. Output can be detected.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a sectional view of the first embodiment.

FIG. 3 is an explanatory diagram of the operation of the first embodiment.

FIG. 4 is a diagram showing a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of the second embodiment.

FIG. 6 is a diagram showing a third embodiment of the present invention.

FIG. 7 is a diagram showing a fourth embodiment of the present invention.

FIG. 8 is a partial perspective view of a conventional magnetic rotation sensor.

FIG. 9 is a cross-sectional view illustrating the operation of a conventional magnetic rotation sensor.

FIG. 10 is a sectional view illustrating the operation of a conventional magnetic rotation sensor.

[Explanation of symbols]

1, 10, 20, 30 Rotating member 11, 12, 21, 22, 31, 32 Multipolar magnetized surface 4
0 Magnetic detection sensor 60, 61, 62, 63 Resin mold 13, 14
Mounting parts

Claims (1)

[Claims] 1. A cylindrical rotating shaft, a rotating member through which the rotating shaft concentrically extends, a fixed member rotatably supporting the rotating shaft, and a region extending radially from the center of the rotating member. a ring-shaped first multipolar magnetized member that is separated and magnetized so that adjacent regions have opposite polarities, is provided on the rotating member, and rotates integrally with the rotating member; a ring-shaped second multipolar magnetized member that is provided on the rotating member so that the opposing region has opposite polarity, and rotates integrally with the rotating member; and a magnetic field generated by the first and second multi-pole magnetized members, which is covered with resin and fixed to the fixed member between the first and second multi-pole magnetized members. A magnetic rotation sensor having a magnetic detection sensor for detecting