JPH08184603A - Magnetic sensor-containing bearing unit - Google Patents

Abstract

PURPOSE: To sense a complicated magnetizing pattern with high accuracy and to easily handle it in a bearing unit in which the rotation of a rotational shaft supported to a bearing can be detected by a magnetic sensor. CONSTITUTION: A magnet wheel 5 is engaged with the inner ring 2 of a bearing, a magnet 8 is mounted on the flange 6 of the wheel 5, and a wide magnetizing surface 9 is formed. A sensor unit 10 is assembled inside the extended part 3a of an outer ring 3, and a magnetic sensor 12 opposed to the surface in an axial direction is provided on the end face of the unit 10. Sensor positioning means 16 for regulating the air gap amount X between the surface 9 and the sensor 12 is provided on the end of the ring 3, and the sensing accuracy of a magnetizing pattern is raised by regulating the suitable air gap amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing unit for detecting a rotation angle and a rotation speed of a rotary shaft by a magnetic sensor.

[0002]

2. Description of the Related Art A bearing unit provided with a magnetic sensor is used in parallel with a bearing or a part of the bearing is inserted in the bearing to detect a rotation angle and a rotation speed of a rotary shaft.

FIG. 16 shows a conventional bearing unit of this type, in which a magnetic sensor 46 is attached to the end of the rolling bearing 41 by utilizing the seal grooves 44 and 45 of the inner ring 42 and the outer ring 43.

The magnetic sensor 46 is fixed by penetrating a support ring 47 attached to the outer ring 43, and
An annular magnet 49 having a magnetized surface 48 is attached to the second seal groove 44 so as to face the magnetic sensor 46. A seal member 50 is attached between the support ring 47 and the magnet 49.

In this structure, the rotating shaft B is provided inside the inner ring 42.
When the magnet 49 rotates together with the rotation axis B,
A change in magnetism is detected by the magnetic sensor 46, and a signal corresponding to the rotation is output through the code 51.

[0006]

However, the conventional bearing unit in which the magnetic sensor and the magnet are incorporated in the bearing as described above has the following problems in practical use.

The seal groove 44 of the bearing is used for mounting the magnet 49.
However, since the mounting space is limited, it is impossible to use a large magnet with a small bearing. For this reason, there is a limit to the size of the magnetized surface 48, it is difficult to magnetize a plurality of complicated patterns, and it is difficult to expect the accuracy of rotation speed detection to be improved.

Since the magnetic sensor 46 and the magnet 49 are directly fixed to the seal grooves 44, 45 of the bearing, the air gap amount X between the sensing portion of the magnetic sensor and the magnet surface is
Although it is uniquely determined by the dimensional accuracy of each component, if the air gap amount X varies,
It is not possible to accurately sense the magnetism of the magnet 49 that is finely magnetized in multiple poles. For this reason, it is necessary to increase the magnetizing width of the magnet 49 in order to increase the sensing accuracy of the sensor. However, as described above, the magnet 49 has a limited mounting space. I can't. Also,
If the accuracy of the parts is increased, the variation in the air gap amount can be reduced, but such an improvement in the accuracy of the parts has a drawback that the cost of the product is increased.

In the structure in which the magnetic sensor 46 and the magnet 49 are attached to the bearing using the seal grooves 44 and 45, a part of the sensor has a shape protruding from the end surface of the bearing, and the sensor is damaged during transportation or mounting of the bearing unit. Or the amount of air gap may change due to deformation. Further, in this structure, it is necessary to consider the surrounding structure for mounting the bearing unit so as not to make strong contact with the protruding portion of the sensor.

In the structure in which the rotating shaft B is directly fitted to the inner ring 42 of the bearing, it is necessary to fit the inner ring 42 and the outer ring 43 to the rotating shaft and the housing in a tight fit.
In that state, it is necessary to accurately align the pull-out position of the sensor cord 51 with the direction of signal output, so that a difficult work is required for assembling the bearing unit.

An object of the present invention is to solve the above-mentioned problems with the bearing unit.

[0012]

SUMMARY OF THE INVENTION In order to solve the above problems, according to the present invention, a magnet ring having a flange serving as a magnetized surface is fitted inside the inner ring of the bearing, and the outer ring of the bearing is A magnetic sensor that extends in the axial direction beyond the flange of the magnet ring and inside the extension of the outer ring that faces the magnetized surface of the magnet ring in the axial direction, and a circuit that outputs the signal of the magnetic sensor to the outside. The sensor unit having the section is incorporated.

In the above structure, the magnetized surface is provided on the flange of the magnet ring which is separate from the inner ring, and the magnetic sensor is axially opposed to the flange, so that the space of the magnetized surface can be arbitrarily large. This makes it possible to form a plurality of magnetization patterns on the magnet.

Further, since the shaft sensor and the circuit portion are housed inside the extension portion of the outer ring, it is possible to prevent the sensor from protruding from the bearing.

Further, in the above structure, the extension portion of the outer ring may be provided with a positioning means capable of arbitrarily adjusting the axial arrangement position of the magnetic sensor with respect to the magnet ring.

According to this structure, the air gap amount between the magnetic sensor and the magnet can be optimally set, and the magnetic sensor can accurately detect the change in magnetism.

Further, a spline for connecting the rotating shaft may be formed on the inner diameter of the flanged member, and a long hole for screwing long in the circumferential direction may be provided on the outer ring of the bearing.

According to this structure, the magnet ring and the rotary shaft are connected via the spline, and the outer ring is rotated in the circumferential direction within the range of the length of the long hole, so that the signal output positions are adjusted so as to match each other. Since it can be adjusted, the mounting position error between the inner and outer rings can be eliminated.

Further, the outer diameter surface of the outer ring of the bearing may be formed as a spherical surface that fits into the inner spherical surface of the pillow type bearing box, and the flanged member may be provided with a fixing means for fixing to the rotating shaft. it can.

According to this structure, the outer ring freely swings due to the fitting of the spherical surfaces, and the mounting error of the bearing unit can be absorbed.

Although the bearings are assembled in a single row in each of the above constructions, the air gap amount between the magnetized surface and the magnetic sensor may vary due to the axial clearance of the bearings.
Of course, even with such a configuration, there is no problem in sensing when the magnetization pitch is large, but when it is small, a sufficient sensor output cannot be obtained and a normal signal may not be output.

Therefore, when many fine magnetizations are to be performed in order to obtain many signals in one rotation, the magnet diameter is increased in order to increase the magnetization pitch, or the bearings are double-rowed and preloaded. Therefore, it is necessary to eliminate the axial clearance of the bearing.

However, when the magnet diameter is increased, the diameter of the entire sensor unit is increased, and when the same bearing is arranged in a double row, the dimension in the axial direction becomes large.

In order to solve these problems, the present invention has an improved structure of the above-mentioned invention, which is a bearing unit with a built-in magnetic sensor for detecting the rotation angle or the rotation speed of a rotating shaft supported by a bearing by a magnetic sensor. In, the bearing fixing member is fitted inside the inner ring of the bearing, and the magnet ring is fitted to the inner end surface of the bearing fixing member while allowing relative movement in the axial direction and preventing relative movement in the circumferential direction. An elastic body having elasticity that separates the magnet ring and the bearing fixing member from each other in the axial direction is interposed, and the outer ring of the bearing is extended in the axial direction beyond the magnet ring to provide an extension portion, Inside the extension portion, a sensor unit having a magnetic sensor that axially faces the magnetized surface of each magnet ring and a circuit portion that outputs the signal of the magnetic sensor to the outside is incorporated, and the magnet surface of the sensor unit is included. Opposite A shaft portion is formed at the center of the curved surface, an internal bearing fitted to the shaft portion is interposed between the magnet ring and the sensor unit, and the elastic body faces the bearing and the internal bearing in opposite axial directions. The configuration with the preload added was adopted.

According to the above construction, the shaft fixing member and the magnet ring are pressed by the elastic body in the axially separating directions, and preload is applied to the bearings of both bearings to eliminate the axial skimmer. As a result, there is no fluctuation in the air gap amount between the magnetized surface of the magnet ring and the magnetic sensor.

Further, since the air gap amount is determined by the width dimension of the internal bearing, the air gap amount adjusting means becomes unnecessary.

Further, since the load applied to the internal bearing is only the axial load by the elastic body, the internal bearing may be a small diameter bearing having a small load capacity, and therefore, the increase in the width of the entire unit can be suppressed. You can

A standard bearing is used as the bearing, an independent housing is provided in place of the extension of the bearing outer ring, the outer ring of the standard bearing is fitted inside the housing, and the sensor unit is attached to the housing. It is also possible to adopt a configuration in which the inside is fitted with a tight fit.

According to the above construction, the bearing is a standard type, the metal disc and its mounting screw can be omitted, and the cost can be reduced.

[0030]

1 to 3 show a first embodiment of the present invention. The bearing unit of this embodiment includes a rolling bearing 1 in which balls 4 are incorporated between an inner ring 2 and an outer ring 3, and a magnet ring 5 is fitted to the inner diameter portion of the inner ring 2 of the bearing 1. .

This magnet ring 5 is formed of a cylindrical portion 6 fitted to the inner ring of the inner ring 2 and a flange 7 having a diameter dimension close to the inner diameter surface of the outer ring 3, and a magnetic field is applied to the outer surface of the flange 7. A generating magnet 8 is attached. As shown in FIG. 3, a magnetized surface 9 is formed on the end surface of the magnet 8 by alternately magnetizing N poles and S poles in different patterns on the inner diameter side and the outer diameter side.

The outer ring 3 of the bearing 1 is extended in the axial direction beyond the flange 7 of the magnet ring 5, and a disc-shaped sensor whose outside is integrally covered with a resin mold 11 inside the extension 3a. The unit 10 is incorporated.

This sensor unit 10 has a magnetic sensor 12 having an MR element, a Hall element, etc. on its inner end surface.
And an electronic circuit 13 that amplifies the sensing signal of the magnetic sensor 12 and converts it into a rectangular wave or the like. When the sensor unit 10 is incorporated inside the outer ring 3, the surface of the magnetic sensor 12 is a magnet. It is arranged to face the magnetized surface 9 of the wheel 5 in parallel with the axial direction.

A connector 15 is provided on the outer end surface of the sensor unit 10 to electrically connect it to the electronic circuit 13 via the conductor 14. The connector 15 is used to output signals and supply power. It has become. In addition,
Instead of the connector 15, a cord may be directly connected to the sensor unit 10 so that the sensor unit 10 can be connected to an external terminal.

On the other hand, on the end surface of the extension portion 3a of the outer ring 3, the sensor positioning means 16 for adjusting the axial arrangement position of the magnetic sensor 12 with respect to the magnetized surface 9 of the magnet ring 5.
Is provided.

The sensor positioning means 16 includes a metal disc 17 fixed to the outer end surface of the sensor unit 10 by adhesion or the like, a screw 18 for fixing the metal disc 17 to the extension 3a of the outer ring 3, and a metal circle. It is composed of a plate 17 and a spacer 19 sandwiched between the outer ring 3, and by changing the number and thickness of the spacers 19, the mounting position of the sensor unit 10 with respect to the outer ring 3 is changed in the axial direction, and the magnet 8 and the magnetic The air gap amount X between the sensors 12 can be changed.

This embodiment has the structure as described above, and when the rotary shaft B is inserted into the inner diameter of the magnet ring 5 and the magnet ring 5 rotates together with the rotary shaft B, the magnetism generated from the magnetized surface 9 rotates. Then, the magnetic sensor 12 senses the change in the magnetism. The output signal from the magnetic sensor 12 is the electronic circuit 1
The signal is amplified and waveform-processed in 3, and is directly input to the control device or the like which performs signal processing from the connector 15 in a state of being processed in any form.

When the rotational speed is detected as described above, in order to detect the magnetism of the magnet 8 magnetized in multiple poles with high accuracy by the magnetic sensor 12, the air gap amount X between them is set to an optimum value. Must be set to.

Such adjustment of the air gap amount is first performed when the sensor unit 10 is assembled in the outer ring 3 of the bearing.
The distance from the end surface of the outer ring 3 to the magnetized surface 9 of the magnet 8 is measured, and the measured value is combined with the distance between the metal disk 17 of the sensor unit 10 and the surface of the magnetic sensor 12 to obtain the optimum air gap amount. A spacer 19 having a thickness dimension for obtaining X is selected, and the spacer 19 is sandwiched between the end surface of the outer ring 3 and the metal disc 17. Next, by fixing the metal disk 17 to the outer ring 3 with the screw 18, the magnetic sensor 12 of the sensor unit 10 is positioned and fixed to the magnet 8 via the optimum air gap amount X, and stable sensing is performed. Can be done.

Although the metal disk 17 is formed separately from the sensor unit 10 in the above example, it may be formed integrally with the material of the sensor unit 10.

FIG. 4 shows a second embodiment. In this example, the sensor positioning means 1 for adjusting the air gap amount X is used.
6 is another structure applied to the outer ring 3 and the extension 3
Threads 21 and 22 are formed on the inner diameter surface of a and the outer diameter surface of the sensor unit 10, respectively, so that the sensor unit 10 can be housed in the outer ring 3 by screwing.

In the above structure, the thread 2
With the adhesive applied to Nos. 1 and 22, the sensor unit 10 is screwed into the inner side of the outer ring until the magnetic sensor 12 and the magnet 8 come into contact with each other, and then the sensor unit 10 is moved by an amount corresponding to an appropriate air gap amount X. After turning in the backward direction, the sensor unit 10 is fixed with an adhesive.

5 and 6 show a third embodiment. In this example, three or more spiral grooves 23 are formed on the outer diameter surface of the sensor unit 10 and the inner diameter surface of the extension portion 3a of the outer ring 3 is formed. ,
A semicircular groove 24 is formed over the entire circumference, and the spiral groove 2 is formed.
A steel ball 25 is fitted between 3 and the semicircular groove 24.

In the above structure, when the sensor unit 10 is rotated, the steel ball 25 rolls, and the lead of the spiral groove 23 causes the sensor unit 10 and the outer ring 3 to relatively move in the axial direction. The method for adjusting the air gap amount X is the sensor unit 1
0 is applied to the outer diameter surface and the inner diameter surface of the outer ring 3, and the sensor unit 10 is rotated in the extracting direction so that an appropriate air gap amount X can be obtained from the state where the magnetic sensor 12 and the magnet 8 are in contact with each other. , In that state, fix it with an adhesive.

On the other hand, in the fourth embodiment shown in FIG. 7, the outer peripheral portion of the metal disk 17 fixed to the sensor unit 10 is provided with the collar portion 26 fitted outside the extension portion 3a of the outer ring 3,
A V-shaped caulking groove 27 is formed on the outer diameter surface of the extension portion 3a.

In this structure, as in the first embodiment described above, the optimum air gap is determined from the distance from the outer ring 3 end surface to the magnet 8 surface and the distance from the metal disk 17 to the magnetic sensor 12 surface. A spacer 19 capable of forming the amount is selected, and the spacer 19 is sandwiched between the metal disc 17 and the end face of the outer ring 3, and the flange portion 26 of the metal disc 17 is caulked to fix the outer ring 3 and the sensor unit 10. To do so.

Further, in the above structure, when the spacer is not used, the magnetic sensor 12 and the magnet 8 are brought into contact with each other and then separated from each other to obtain an appropriate air gap amount, and thereafter, the brim portion of the metal disk 17 is provided. Make 26 crimp.

8 and 9 show a fifth embodiment.

The basic structure of this embodiment is the same as that of the first embodiment described above, but a spline 31 is formed on the inner diameter surface of the magnet ring 5 and is connected to the rotary shaft B via the spline 31. There is a difference in what I did.

Further, a flange 32 is provided at the end portion of the outer ring 3, and elongated holes 33 for screwing are formed in a plurality of places of the flange 32 so as to be long in the circumferential direction.

In the above structure, the magnet ring 5 and the rotary shaft B can be connected via the spline 31, and it is not necessary to join them in a tight fit, so that the bearing unit and the rotary shaft can be easily connected.

When the outer ring 3 is fixed to the housing or the like with screws, the mounting hole is the elongated hole 33.
The outer ring can be rotated and fixed in the circumferential direction within a required range, and therefore, the connector 15 of the sensor unit 10 can be fixed.
Fine adjustment can be performed so that the position and the position of the signal input by the external device are accurately matched.

FIGS. 10 and 11 show a sixth embodiment, which has a structure in which the bearing unit A is incorporated in the pillow type bearing housing C.

The outer diameter surface of the outer ring 3 of the bearing 1 is formed by a spherical surface 35 which fits into the inner spherical surface 34 of the pillow type bearing box C, and the outer ring 3 freely swings inside the bearing box C. It is possible to absorb a mounting error between the outer ring 3 and the magnet ring 5.

Further, the cylindrical portion 6 of the magnet ring 5 is axially extended from the end face of the inner ring 2, and the cylindrical portion 6 is extended to the extended portion 6a.
Is formed in a radial direction, and the rotary shaft B is fixed by utilizing the screw hole 36, so that the bearing unit and the rotary shaft can be easily attached.

FIG. 12 shows a seventh embodiment, in which a magnet wheel for mounting the magnet 9 is formed integrally with the rotary shaft B.

By having such an integral structure, there is an advantage that the assembling becomes easier and the number of parts can be reduced.

FIGS. 13 and 14 show an eighth embodiment, in which the magnet ring 5 in the first embodiment is separated into two members, a bearing fixing member 5a and a magnet ring 5b. The bearing fixing member 5a is fitted inside the inner ring 2 of the rolling bearing 1 and has a collar 37 formed in an annular shape on the inner end surface thereof. The collar 37 contacts the inner end surface of the inner ring 2. Also,
The stepped portion 3 having an enlarged diameter at the inner end of the shaft hole 38 of the bearing fixing member 5a.
9 are formed, and radial slits 40 are formed at two centrally symmetric locations on the inner surface of the collar 37, extending from the peripheral surface of the collar 37 to the step 39 (see FIG. 14).

On the surface of the magnet ring 5b facing the bearing fixing member 5a, a protruding fitting portion 41 which fits into the step portion 39 is formed, and the protruding fitting portion 41 is provided at two centrally symmetrical positions. A radial protrusion 42 that fits into the slit 40 is formed.
As a result, the bearing fixing member 5a and the magnet ring 5b are fitted in a state where relative movement in the axial direction is allowed and relative movement in the circumferential direction is blocked.

An annular elastic body 43 is interposed between the step portion 39 of the bearing fixing member 5a and the protruding fitting portion 41 of the magnet ring 5b. This elastic body 43 is a wave washer,
The bearing fixing member 5a and the magnet ring 5b are made of rubber or the like.
It has elasticity to separate and in the axial direction.

A recess 44 is provided in the center of the other surface (inner surface) of the magnet ring 5b, and the magnetized surface 9 is provided around the recess 44.
Are formed, and the magnetic sensors 12 and 1 of the sensor unit 10 are formed.
2 and 2 with a constant air gap amount X.

A shaft portion 45 is provided at the center of the surface of the sensor unit 10 on the magnet ring 5b side, and an inner ring 47 of an internal bearing 46, which is a rolling bearing, is fitted to the shaft portion 45. The inner end surface of the inner ring 47 abuts on a step portion 48 formed around the shaft portion 45.

The outer ring 49 of the inner bearing 46 is fitted in the recess 44, and the outer end face of the outer ring 49 is recessed.
It contacts the stepped portion 50 formed on the bottom of No. 4.

The outer ring 3 of the bearing 1 has an extension portion 3a, and the sensor unit 10 is fitted to the extension portion 3a, and a lid made of a metal disc 17 is attached to the extension portion 3a. It is covered and fixed to the extension portion 3a by a screw 18. The circuit unit of the magnetic sensor 12 is built in the sensor unit 10, and a signal is taken out to the outside through the connector 15.

The eighth embodiment is as described above,
Due to the elasticity of the elastic body 43, the bearing fixing member 5a and the magnet ring 5 are
A preload is applied to b in the direction of separating from the axial direction.

Due to the preload, the bearing fixing member 5a is pressed outward by the flange 37 against the inner ring 2 of the bearing 1, and the reaction force is applied to the sensor unit 10 through the outer ring 3, its extension 3a and the metal disk 17. It is supported and the axial gap is absorbed.

Further, the magnet ring 5b presses the outer ring 49 of the inner bearing 46 inward by the step portion 50, and the reaction force is supported by the step portion 48 of the sensor unit 10 through the inner ring 45, and the axial gap is absorbed. To be done.

The air gap amount X between the magnetized surface 9 and the magnetic sensor 12 is determined by the width of the internal bearing 46 interposed between the magnet ring 5b and the sensor unit 10, and the accuracy of the air gap is determined. It is not affected by the axial clearance of each bearing 1, 46, but only by the mounting accuracy of the internal bearing 46. Therefore, there is no change in the air gap amount as in the above-described embodiments, and the spacer 19 (see FIG. 1) for adjusting the air gap amount is not necessary.

Further, since the internal bearing 46 receives only the axial load of the elastic body 43, it may be a small diameter bearing having a small load capacity. Therefore, the increase in the width of the entire unit can be suppressed.

The ninth embodiment shown in FIG. 15 is a bearing 1 '.
As a standard ball bearing having an outer ring 3 having the same width as that of the inner ring 2, the outer ring 3 is fitted inside the housing 51, and the sensor unit 10 is fitted tightly inside the housing 51. is there. Other configurations and operations are similar to those of the above-described eighth embodiment.

In this ninth embodiment, standard bearings can be used, and screws 18 (see FIG. 1) and metal disk 17 can be omitted.

[0072]

According to the invention of claim 1, the magnetized surface is formed on the magnet ring attached to the inner ring of the bearing, and the magnetic sensor is axially opposed to the magnetized surface. Therefore, the area of the magnetized surface can be arbitrarily increased. Since it can be set and a complicated magnetization pattern can be introduced, rotation can be detected with high accuracy.

Further, since the magnetic sensor and the electronic circuit are housed and protected inside the outer ring of the bearing, handling and transportation are facilitated and stable operation can be maintained.

According to the second aspect of the present invention, the air gap amount between the magnetic sensor and the magnetized surface can be optimally set.
Even a complicated magnetization pattern can be accurately sensed by the magnetic sensor, and many output signals can be output during one rotation.

According to the third and fourth aspects of the present invention, since the bearing unit and the rotary shaft or the housing can be easily connected, the assembling work can be simplified.

According to the fifth aspect of the present invention, the air gap amount between the magnetized surface and the magnetic sensor is not affected by the axial clearance of the bearing, so that it can be maintained with high accuracy, and the internal bearing can be maintained. Since a small diameter bearing is sufficient, it has little influence on the width dimension of the entire unit.

The invention according to claim 6 can further reduce the cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment.

FIG. 2 is an enlarged sectional view showing the sensor positioning means of the above.

FIG. 3 is an exploded perspective view of the above.

FIG. 4 is a vertical sectional view showing a second embodiment.

FIG. 5 is a vertical sectional view showing a third embodiment.

FIG. 6 is a partial vertical cross-sectional view showing the main part of the above.

FIG. 7 is a vertical sectional view showing a fourth embodiment.

FIG. 8 is a vertical sectional view showing a fifth embodiment.

FIG. 9 is a view showing a long hole for screwing the same as above.

FIG. 10 is a vertical sectional view showing a sixth embodiment.

FIG. 11 is a perspective view of the above.

FIG. 12 is a vertical sectional view showing a seventh embodiment.

FIG. 13 is a vertical sectional view showing an eighth embodiment.

FIG. 14 is a sectional view taken along line XIV-XIV of FIG.

FIG. 15 is a vertical sectional view showing a ninth embodiment.

FIG. 16 is a sectional view showing a conventional example.

[Explanation of symbols]

 1 Bearing 1'Standard Bearing 2 Inner Ring 3 Outer Ring 3a Extension 5 Magnet Ring 5a Bearing Fixing Member 5b Magnet Wire 6 Cylindrical 7 Flange 8 Magnet 9 Magnetization Surface 10 Sensor Unit 12 Magnetic Sensor 13 Electronic Circuit 15 Connector 16 Sensor Positioning Means 17 Metal disk 19 Spacer 21, 22 Screw thread 23 Helical groove 27 Caulking groove 31 Spline 33 Long hole 34 Internal spherical surface 35 Spherical surface 36 Screw hole 37 Flange 38 Shaft hole 39 Step portion 40 Slit 41 Projection fitting portion 42 Projection portion 43 Elastic body 44 recessed part 45 shaft part 46 inner bearing 47 inner ring 48 step part 49 outer ring 50 step part 51 housing A bearing unit B rotating shaft C pillow type bearing box X air gap amount

Claims (6)

[Claims] 1. In a bearing unit with a built-in magnetic sensor for detecting a rotation angle or a rotation speed of a rotating shaft supported by a bearing by a magnetic sensor, a magnet ring having a flange serving as a magnetized surface is fitted inside an inner ring of the bearing. , The outer ring of the bearing is extended axially beyond the flange of the magnet ring, inside the extension of the outer ring, a magnetic sensor axially opposed to the magnetized surface of the magnet ring, and the magnetic sensor A bearing unit with a built-in magnetic sensor, comprising a sensor unit having a circuit section for outputting a signal to the outside. 2. The bearing unit with a built-in magnetic sensor according to claim 1, wherein the extension portion of the outer ring is provided with positioning means capable of arbitrarily adjusting the axial arrangement position of the magnetic sensor with respect to the magnet ring. 3. A spline for connecting a rotary shaft is formed on the inner diameter of the magnet ring, and a long hole for screwing is provided in the outer ring of the bearing in the circumferential direction. 2. A bearing unit with a built-in magnetic sensor according to 2. 4. An outer diameter surface of an outer ring of the bearing is formed as a spherical surface that fits into an inner spherical surface of a pillow type bearing box, and a flanged member is provided with a fixing means for fixing to a rotary shaft. The bearing unit with a built-in magnetic sensor according to claim 1. 5. In a bearing unit with a built-in magnetic sensor for detecting a rotation angle or a rotation speed of a rotating shaft supported by a bearing by a magnetic sensor, a bearing fixing member is fitted inside an inner ring of the bearing, and the bearing fixing member is fitted. The magnet ring is allowed to move relative to the inner end surface in the axial direction and is fitted so as to prevent the relative movement in the circumferential direction, and an elastic force for axially separating the magnet wheel and the bearing fixing member is provided. The outer ring of the bearing is extended in the axial direction beyond the magnet ring to provide an extension with an elastic body having a magnetic field that axially faces the magnetized surface of each magnet ring inside the extension. A sensor unit having a sensor and a circuit unit for outputting the signal of the magnetic sensor to the outside is incorporated, and a shaft portion is formed at the center of the surface facing the magnet surface of the sensor unit, and the inside fitted to the shaft portion. Set the bearing to the magnet ring and sensor unit. And a bearing unit with a built-in magnetic sensor, wherein the elastic body applies a preload to the bearing and the internal bearing in opposite axial directions. 6. A standard bearing is used as the bearing, an independent housing is provided in place of the extension of the bearing outer ring, the outer ring of the standard bearing is fitted inside the housing, and the sensor unit is attached to the housing. The bearing unit with a built-in magnetic sensor according to claim 5, wherein the bearing unit is fitted to the inner side of the bearing with a tight fit.