WO2006115162A1

WO2006115162A1 - Bearing having rotary sensor

Info

Publication number: WO2006115162A1
Application number: PCT/JP2006/308294
Authority: WO
Inventors: Hiroyoshi Ito
Original assignee: Ntn Corporation
Priority date: 2005-04-21
Filing date: 2006-04-20
Publication date: 2006-11-02

Abstract

In a bearing having rotary sensor used in a motor, it is possible to prevent erroneous operation of the sensor caused by the affect of magnetic field leak. Rare earths are used as a magnetic material of a magnetic encoder (13) as a member of the bearing having rotary sensor. A fluorine-based rubber is used as their binder so as to generate stronger magnetic force than the conventional ferrite-based material, thereby excluding the affect of the magnetic field leak and improving the shock resistance.

Description

Specification

Bearing with rotation sensor

Technical field

TECHNICAL FIELD [0001] The present invention relates to a bearing with a rotation sensor incorporated in a motor and used for detecting the rotational speed and direction of the motor.

Background art

[0002] Conventionally known bearings with rotation sensors include an inner ring, an outer ring, and a plurality of rolling elements interposed between the inner ring and the outer ring, and either the inner ring or the outer ring is a rotating side race ring. On the other hand, the other side is defined as the fixed side ring, and a magnetic encoder provided with alternating magnetic poles of different polarities at a constant pitch in the circumferential direction is fixed to the core metal mounted on the rotation side ring and mounted on the fixed side ring. In this configuration, a magnetic sensor facing the magnetic encoder is mounted on a metal core (see Patent Document 1).

FIG. 11 shows a state where the conventional bearing 41 with the rotation sensor is incorporated in the motor 42. In this figure, 43 is a motor spindle, 44 is a motor rotor, 45 is a motor stator, 46 is a motor housing, and 47 is a magnetic loop of a leakage magnetic field. An annular member 54 is attached to the outer ring 51 of the bearing 41, and a magnetic sensor 53 is mounted on the inner peripheral surface thereof. Further, a core bar 55 facing the annular member 54 is attached to the inner ring 48, and a magnetic encoder 52 facing the magnetic sensor 53 is attached to the core bar 55. In addition, a sealing portion 56 extending radially toward the inner ring 48 is provided at a portion where the annular member 54 is attached to the outer ring 51.

As shown in the figure, the magnetic flux generated from the motor stator 45 flows from the motor housing 46 into the outer ring 51. The flow is broadly divided into: outer ring 51 → ball 49 → inner ring 48 → motor spindle 43 → motor rotor 44 → flow to stator 45 a and outer ring 51 → magnetic sensor 53 → magnetic encoder 52 → inner ring 48 → motor spindle 43 → There is a magnetic flux b flowing from the motor rotor 44 to the motor stator 45.

Of these, the magnetic flux flow b becomes a leakage magnetic flux and passes through the magnetic sensor 53, causing a malfunction of the magnetic sensor 53. [0006] The effect of leakage flux will be described with reference to Figs. 12 (a) to 12 (c). Figure 12 (a) shows the magnetic waveform A and the output signal B extracted with the value S as the reference, under the influence of the leakage magnetic field. The duty ratio (TpZTn X 100) for output signal B is 50%. On the other hand, Fig. 12 (b) shows the case where the leakage magnetic field is applied in the + direction of the magnetic pole, and the magnetic waveform Α, which is affected by the leakage magnetic field, shows a state where the waveform is offset by + C in the + direction. Show. In this case, the duty ratio of the output signal B ′ is much larger than 50%. The value of the duty ratio is relatively large, which means that the influence of the leakage magnetic field is even greater.

[0007] The magnitude of the offset amount C indicates the magnitude of the leakage magnetic field. When the offset amount C is further increased than in the illustrated case, the value of the duty ratio is further increased. In the worst case, the output signal is high. — There is no repetition of Low, and the rotation speed cannot be detected. Fig. 12 (c) shows the case where the leakage magnetic field is added to the-side (when the offset is -C).

[0008] As a magnetic material of the conventional magnetic encoder 52, inexpensive powder ferrite is usually used, and HNBR, which is a heat-resistant rubber, is used as a binder.

[0009] Further, as means for eliminating the influence of leakage magnetic flux of a motor or the like and improving detection accuracy by the magnetic sensor, a plurality of magnetic sensors are arranged in the circumferential direction, and differential output means for each output signal Conventionally, it has been known to eliminate the influence of the leakage magnetic field by processing the signal as an encoder signal for one phase (see Patent Document 2).

On the other hand, in order to prevent the influence of leakage magnetic flux on the magnetic sensor 53 by using the seal portion 56 of FIG. 11 as a magnetic bypass, a magnetic bypass separate from the annular member 54 as shown in FIG. Conventionally known is a bearing with a rotation sensor in which a ring 57 is fitted and integrated (Patent Document 3).

In this bearing 41, an annular member 54 is fitted and fixed to an outer ring 51, and a magnetic sensor 53 is attached to a sensor case 58 provided on an inner diameter surface of the annular member 54, and the magnetic sensor 53 is attached to an inner ring 48. A magnetic encoder 52 mounted via a cored bar 55 is disposed to face the cored bar 55. One end portion of the side plate member 59 joined and integrated with the tip end portion of the annular member 54 is brought close to the inner diameter surface of the core metal 55 via a predetermined circuit gap gl. In addition, an inverted L-shaped outer peripheral edge of the magnetic bypass ring 57 is press-fitted integrally with the inner end portion of the annular member 54, and the inner peripheral edge is brought close to the core metal 55 via a predetermined bypass gap g2. (Patent Reference 1).

[0012] The leakage flux Φ flowing into the outer ring 51 is divided into Φ 1 and Φ 2, and Φ 1 is derived from the main magnetic circuit, that is, the annular member 54, the side plate member 59, the circuit gap gl, the cored bar 55, and the inner ring 48. (However, there is also a circuit that leads to circuit gap gl → magnetic encoder 52 → encoder gap g3 → magnetic bypass ring 57 → inner ring 48). Φ 2 passes through a no-pass magnetic circuit, that is, a circuit composed of the magnetic binos ring 61 and the bypass gap g2.

[0013] The main magnetic circuit and the bypass magnetic circuit described above have a function of surrounding the magnetic sensor 53 to shield an external magnetic field to prevent malfunction and to improve the accuracy of the magnetic sensor.

Patent Document 1: Japanese Patent Laid-Open No. 2003-302254

Patent Document 2: JP-A-2004-117318

Patent Document 3: Japanese Patent Laid-Open No. 2002-174258

Disclosure of the invention

Problems to be solved by the invention

[0014] However, there is a limit to increasing the magnetic force when using a ferrite material that has been used generally as a magnetic encoder material, and it is effective to avoid the influence of a large leakage magnetic field. Can not. The use of the differential output means has a problem that the number of magnetic sensors increases and the electric circuit becomes complicated, resulting in high cost.

[0015] Therefore, the present invention enhances the magnetic force by selecting the magnetic material of the magnetic encoder that does not depend on an electric circuit, thereby eliminating the influence of a leakage magnetic field generated by a force such as a motor and improving the detection accuracy by the magnetic sensor. Is the first issue.

In addition, as shown in FIG. 13, the annular member 54 in the conventional bearing with a rotation sensor is formed with an L-shaped fixing portion 60 fitted to one end face and the inner face of the outer ring 51 to form a magnetic The bypass ring 57 is formed with an inverted L-shaped outer peripheral edge 61 that is press-fitted into the inner diameter surface of the fixed portion 60. The annular portion 54 and the magnetic bypass ring 57 are independently pressed and then subjected to a process of fitting and integrating with each other, and then assembled to the bearing. Therefore, before assembling to the bearing, a processing step for forming each member by press working and a processing step for fitting and integrating each member are required. [0017] Further, when the annular member 54 and the magnetic bino ring 57, which are integrally fitted, are assembled to the outer ring 51, the magnetic bypass ring 57 is further subjected to compressive stress due to press-fitting, so that the axial position is shifted. There is. Further, since the fitting width between the annular member 54 and the magnetic bypass ring 57 cannot be designed to be large, there is a problem that the magnetic bypass ring 57 tends to be inclined during the press-fitting. Furthermore, the process of fitting and integrating the magnetic bypass ring 57 with the annular member 54 takes time, and there is a problem that increases costs.

[0018] Further, since the magnetic bypass ring 57 is provided in the vicinity of the magnetic sensor 53, the magnetic flux Φ3 leaked from the magnetic bypass ring 57 may pass through the magnetic sensor 53 and the magnetic encoder 52. It causes a decrease.

Therefore, the present invention solves various problems related to the annular member 54 and the magnetic bypass ring 57, reduces the cost by improving productivity, and the magnetic shielding effect by the magnetic bypass ring 57. The second problem is to improve the detection accuracy of the magnetic sensor 53 by increasing the value.

Means for solving the problem

In order to solve the first problem, the present invention includes an inner ring and an outer ring 2 and a plurality of balls 6 interposed between the inner ring 1 and the outer ring 2 as shown in FIG. One of the inner ring 1 and the outer ring 2 is defined as a rotation-side raceway, and the other is defined as a fixed-side raceway. In the illustrated case, the inner ring 1 is defined as the rotating raceway. A magnetic encoder 13 in which magnetic poles of different polarities are alternately formed at a constant pitch in the circumferential direction is attached to a metal core 8 attached to the inner ring 1, and the magnetic encoder 13 is attached to an annular member 9 attached to a stationary raceway. In the bearing with the rotation sensor mounted with the magnetic sensors 28 and 29 opposite to each other, the magnetic material of the magnetic encoder 13 is a rare earth magnetic material, and a fluorine rubber is used as the binder. .

[0021] A samarium-based material can be used as the rare earth-based magnetic material. In addition, a material obtained by kneading the rare earth magnetic material into a rubber material can be used.

In order to solve the second problem, the present invention comprises an inner ring outer ring 2 and a plurality of balls 6 interposed between the inner ring 1 and the outer ring 2 as shown in FIG. One of the inner ring 1 and the outer ring 2 is defined as a rotation-side raceway, and the other is defined as a fixed-side raceway. In the case of illustration The inner ring 1 is defined as the rotating raceway. A magnetic encoder 13 in which magnetic poles of different polarities are alternately formed at a constant pitch in the circumferential direction is attached to the core 8 attached to the inner ring 1, and the annular member 32 attached to the outer ring 1 which is a stationary raceway is attached to the annular member 32. Magnetic sensors 28 and 29 facing the magnetic encoder 13 are mounted, and one end of the side plate member 23 integrated with the tip of the annular member 32 is connected to the inner diameter surface of the core 8 via a predetermined circuit gap gl. The outer peripheral edge of the magnetic bypass part 35 is integrated with the inner end of the annular member 32, and the inner peripheral edge is made to approach the cored bar 8 through a predetermined bypass gap g2. Thus, in the bearing with a rotation sensor formed by forming a magnetic circuit including the annular member 32, the side plate member 23, the circuit gap gl and the cored bar 8, and a no-pass magnetic circuit including the magnetic bypass portion 35 and the bypass gap g2. ,in front The annular member 32 and the magnetic bypass portion 35 are configured by a single part.

[0023] As a more specific configuration of the annular member 32, the annular member 32 includes a mounting portion 34 and a magnetic bypass portion 35, and the mounting portion 34 matches the shape of the fitting portion of the outer ring 2. L The magnetic bypass part 35 bends in a V shape from the inner end of the fixed part 33 to the inner surface of the inner ring 1 at a constant angle α (see FIG. 2) toward the outside of the bearing. And a radial direction portion 37 formed by bending an end portion of the inclination portion 36 in the radial direction, and the inner peripheral edge of the radial direction portion 37 is binned with the cored bar 8. A configuration for forming the gap g2 can be adopted.

[0024] A V-shaped bent portion 38 is formed by the fixed portion 33 and the inclined portion 36 bent at an angle a. Since the leakage flux Φ2 passes through the inclined portion 36 forming the V-shaped bent portion 38, the path of the leakage flux Φ2 is more magnetic than the conventional magnetic binos ring 57 (see Fig. 13). , 29 and further away. For this reason, even if a leakage magnetic field is generated in the bypass portion 35, the influence on the magnetic sensors 28 and 29 is small. The invention's effect

[0025] As described above, the bearing with a rotation sensor according to the present invention uses a rare earth magnetic material such as samarium as the magnetic material of the magnetic encoder, so that a stronger magnetic force than that of a conventional ferrite material can be obtained. . This makes it difficult for the sensor to be affected by the leakage magnetic field generated by the motor's force when it is incorporated into a motor, etc., and prevents malfunction of the sensor. It is.

[0026] Further, by using fluorine rubber (FKM) as the binder of the magnetic material, the magnetic rubber constituting the magnetic encoder is not broken even when a large impact force is applied, and has high reliability. . This expands the scope of application to power tools that repeatedly start and stop suddenly.

[0027] In addition, according to the bearing with a rotation sensor according to the present invention, the annular member 54 and the magnetic bypass ring 57 that are configured by separate conventional parts are configured by the annular member 32 that is a single component. Therefore, the following effects can be obtained.

(1) Since the conventional annular member 54 and the magnetic bypass ring 57 are constituted by the annular member 32 which is a single part, material is not wasted and material costs are reduced.

(2) Since the annular member 32 is manufactured by press molding, the dimensional accuracy such as the coaxiality of the mounting portion 34 and the bypass portion 35 and the positional accuracy in the axial direction is improved.

(3) It is not necessary to manage the fitting force between the annular member 54 and the magnetic bypass ring 57, which was necessary in the past.

(4) By using magnetic stainless steel as the material of the annular member 32, the magnetic field entering from the outside can be efficiently shielded, and the corrosion resistance is improved.

(5) The position of the magnetic bin portion 35 is not displaced when it is press-fitted into the bearing, and the position becomes accurate.

(6) Since the V-shaped bent portion 38 is formed by the fixed portion 33 and the inclined portion 36, the leakage flux Φ 2 passes through a portion further away from the magnetic sensors 28 and 29. For this reason, the detection accuracy of the magnetic sensors 28 and 29 is improved.

Brief Description of Drawings

[0028] FIG. 1 is a sectional view of Example 1.

[Fig. 2] (a) Cross-sectional view taken along line XI—XI in FIG. 1, (b) Partial cross-sectional view taken along line Y1-Y1 in FIG. 1, (c) Enlarged view of the magnetic pole portion in FIG.

[Figure 3] Explanatory diagram of the relationship between the fixed position of the sensor element and the output waveform

[Fig.4] Sensor output same as above, explanatory diagram of multiplication by phase A and phase B

[Fig.5] Sensor output when affected by accumulated pitch error in doubled state due to phase A and phase B Explanatory drawing

[Fig.6] (a) to (c) Magnetic waveform diagram and output signal waveform diagram

[Fig. 7] Sectional view of Example 2

[Figure 8] Enlarged sectional view of the annular member

[Fig. 9] (a) Same vertical front view, (b) Same vertical front view

[Fig.10] Partial enlarged sectional view of the above

[Fig. 11] Partial cross-sectional view of the conventional example

[Fig. 12] (a) to (c) Conventional magnetic waveform diagram and output signal waveform diagram

[Fig.13] Partially enlarged sectional view of another conventional example

Explanation of symbols

1 Inner ring

2 Outer ring

3 Track groove

4 Track groove

5 Cage

6 balls

7 Seal material

8 cored bar

9 Ring member

10 Rotation sensor

11 Fixed part

12 Mounting part

13 Magnetic encoder

15 magnetic pole

16 Fixed part

17 Mounting part

18 Seal part

19 Sensor holder 21 Electric circuit board

22 ID

23 Side plate member

24 Cylindrical part

25 collar

26 Labyrinth clearance

28 A phase magnetic sensor

29 B-phase magnetic sensor

31 Output Cape Nore

32 Ring member

33 Fixed part

34 Mounting part

35 Magnetic bypass section

36 Slope

37 Radial section

38 V-shaped bend

39 Force squeeze

40 Mold resin

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

Example 1

The rotation sensor bearing of Example 1 shown in FIGS. 1 and 2 is an inner ring rotating type in which the inner ring 1 is defined as a rotating side race ring and the outer ring 2 is defined as a fixed side race ring. A plurality of balls 6 held by a cage 5 are interposed between the raceway grooves 3 and 4 facing each other. On one side surface of the inner ring 1 and the outer ring 2, a seal member 7 attached to the stationary outer ring 2 is brought into contact with the inner ring 1 on the rotating side. A rotation sensor 10 is provided at the end opposite to the side where the seal member 7 is provided.

The rotation side of the rotation sensor 10 includes an annular core 8 that is press-fitted and fixed to the outer diameter surface of the inner ring 1. The magnetic encoder 13 is attached to the magnetic encoder 13. The metal core 8 is provided with a mounting portion 12 having an L-shaped cross section that is bent in the diameter increasing direction at the outer end of the annular fixing portion 11, and the magnetic encoder 13 is mounted on the outer diameter surface of the mounting portion 12.

[0033] As shown in Fig. 2, the magnetic encoder 13 is configured by alternately magnetizing magnetic poles 15 having different polarities with a constant width over the entire circumference at a constant pitch in the circumferential direction. The magnetic flux density of the magnetic encoder 13 tends to decrease and the pitch accuracy tends to decrease as the width of the magnetic pole 15 decreases. Experience shows that the magnetizing width is 0.5 mm or more in the circumferential direction of the magnetic encoder 13 Good things are divided.

As shown in FIG. 1, the annular member 9 constituting the fixed side of the rotation sensor 10 is provided with a mounting portion 17 having an L-shaped cross section at the outer end of the annular fixing portion 16. The portion 17 protrudes longer in the axial direction than the mounting portion 12 on the inner ring 1 side. Further, a seal portion 18 projecting in the radial direction toward the fixed portion 11 on the inner ring 1 side is formed on the entire inner circumference of the fixed portion 16.

In the annular member 9, a sensor holder 19 made of annular grease is mounted on the inner surface of the mounting portion 17 having an L-shaped cross section, and an electric circuit board 21 or the like is inserted into a part of the sensor holder 19. It is fixed integrally by molding or the like. The inner diameter surface of the sensor holder 19 is formed in two steps, the inner diameter being large and the outer diameter being small. The large-diameter inner diameter surface 22 faces the magnetic encoder 13 with a required gap.

The cylindrical portion 24 of the side plate member 23 is inserted into the inner diameter side of the mounting portion 12 of the core metal 8. The side plate member 23 is an annular member having a cross-sectional shape and shape, and includes a cylindrical portion 24 and a flange portion 25 formed outward at the outer end thereof. The outer peripheral edge of the collar portion 25 is fixed to the inner peripheral edge of the outer end portion of the mounting portion 17 of the annular member 9.

The collar portion 25 covers the outer end surface of the sensor holder 19 including the electric circuit board 21.

The cylindrical portion 24 covers the inner peripheral surface of the sensor holder 19 including the electric circuit board 21 and forms a part of the labyrinth gap 26 between the cylindrical portion 24 and the inner peripheral surface of the mounting portion 12 of the core metal 8. The labyrinth clearance 26 is formed between the cylindrical portion 24 and the mounting portion 12, between the outer end surface of the mounting portion 12 and the sensor holder 19, between the magnetic encoder 13 and the sensor holder 19, and between the inner end surface of the mounting portion 12 and the seal. Formed between part 18 and part 18. [0038] An electric circuit board 21 is embedded in a portion of the sensor holder 19 on the small-diameter side over a required range in the circumferential direction. An A-phase magnetic sensor 28 and a B-phase magnetic sensor 29 are also provided on the inner surface of the electric circuit board 21 so as to protrude inwardly at regular intervals in the circumferential direction and also have Hall IC iso-forces (see Fig. 1). Each of the magnetic sensors 28 and 29 is exposed to the large-diameter inner surface 22 of the sensor holder 19 and faces the magnetic pole 15 of the magnetic encoder 13 (see FIGS. 2B and 2C). The interval between the magnetic sensors 28 and 29 is set to an odd multiple of the 0.25 pitch of the magnetization pitch as a reference pitch. Figures 2 (a) and 2 (b) show examples in which the interval is set to 9 times the reference pitch (= 2.25 pitch). Up to about 15 times the standard pitch is possible. In Fig. 2 (a), 31 indicates an output cable.

[0039] As described above, when the interval between the A phase magnetic sensor 28 and the B phase magnetic sensor 29 is set to an odd multiple of the reference pitch, the electrical phase difference between the A phase output signal and the B phase output signal becomes 90 degrees. .

[0040] On the other hand, in the magnetic encoder 13, as the magnetization pitch is increased from the magnetic pole 15 at an arbitrary fixed position, an accumulated pitch error occurs, so the interval between the opposing magnetic sensors 28, 29 (number of pitches) ) Increases, and the phase difference error of the output signal increases. Therefore, in order to create a phase difference of 90 degrees with high accuracy, it is necessary to set the interval between the magnetic sensors 28 and 29 as small as possible. However, magnetic sensors 28 and 29 interfere with each other if they are made smaller than a certain level, so there is a limit to reducing the distance between them.

[0041] Therefore, when the width of the magnetic pole is 0.5 mm or more, the minimum interval is the minimum interval necessary to avoid interference of the magnetic sensors 28 and 29 (1.75 pitch = 0.25 pitch x 7 times) )is required. In addition, the maximum interval can be set to the maximum interval (2.25 pitch = 0.25 pitch x 9 times) that can ignore the influence of the accumulated error of the magnetization pitch.

It should be noted that the interval is the same even if the rotation direction of the magnetic encoder 13 is reversed and the arrangement of the magnetic sensors 28 and 29 is reversed.

FIG. 3 shows the position of the A-phase magnetic sensor 28 relative to the B-phase magnetic sensor 29 when the magnetic encoder 13 rotates clockwise (see arrow A) as shown in FIG. 2 (a). It shows the relationship of the output waveform when the magnetic encoder 13 is separated by an odd multiple of 0.25 pitch in the rotational direction. In FIG. 3, N and S indicate the magnetic poles 15 of the magnetic encoder 13. Each magnetic sensor 28, 29 turns OFF when approaching the N pole, and turns ON when approaching the S pole. Magnetic sensor 28, The output waveform is High when 29 is OFF and Low when it is ON. Figure 4 shows the A phase output waveform multiplied by the B phase output waveform. As shown in the figure, the pitch of the output waveform after multiplication is twice that of the output waveform before multiplication.

FIG. 5 shows an example in which the magnetic encoder 13 is multiplied while the accumulated pitch error is large. It can be seen that if the pitch error of the output waveform of each phase is large, the pitch accuracy after multiplication will deteriorate.

[0045] Although the above embodiment has been described for the inner ring rotating type bearing, it can be similarly applied to the outer ring rotating type bearing.

It is desirable to use a rare earth (neodymium, samarium) material as the magnetic material of the magnetic encoder 13. These rare earth-based magnetic materials are stronger than conventional ferrite-based materials and can provide magnetic force, so they are less susceptible to the leakage magnetic field generated by motors, etc. Can be avoided.

[0047] When the above rare earth magnetic material is used, it is desirable to use fluorine rubber (FKM) as the binder. The magnetic material is kneaded into fluorine rubber and exhibits the properties of magnetic rubber. Compared to conventional HNBR, the tensile strength is approximately double, so even if a large impact force is applied, the magnetic rubber will not be destroyed, so it can be used for power tools.

[0048] Figs. 6 (a) to 6 (c) show that the detection accuracy of the magnetic sensors 28 and 29 is improved when a strong magnetic field is obtained using a rare earth magnetic material as described above. Based on this explanation. The magnetic waveform A in FIG. 6 (a) shows that the magnetic encoder 13 is affected by the leakage magnetic field when the magnetic force is relatively stronger than the magnetic waveform A in FIG. 12 (a). Indicates no state. The magnetic waveform A in Fig. 6 (b) shows the state where the leakage magnetic field is added in the + direction of the magnetic pole and the magnetic waveform A is offset by C in the + direction. In Fig. 6 (a), the value of the duty ratio of the output signal is 50%, whereas in Fig. 6 (b), the value is slightly larger than 50%. It can be seen that the amount of change in the duty ratio is smaller than in b). This is because the angle α of the magnetic waveform A is reduced by increasing the magnetic force. Also, by increasing the magnetic force at the same time, even if an offset is applied, the margin until the peak of the magnetic waveform なくなる no longer crosses the threshold value increases. [0049] Fig. 6 (c) shows a case where a leakage magnetic field is applied to the-side (when the offset amount is -C).

Example 2

Next, a bearing with a rotation sensor according to a second embodiment will be described with reference to FIGS.

The bearing with a rotation sensor of Example 2 is also an inner ring rotating type in which the inner ring 1 is defined as a rotating raceway and the outer ring 2 is defined as a stationary raceway, and between the raceway grooves 3 and 4 facing the inner ring 1 and the outer ring 2, respectively. A plurality of balls 6 held by the cage 5 are interposed. On one side surface of the inner ring 1 and the outer ring 2, a seal member 7 attached to the stationary outer ring 2 is brought into contact with the inner ring 1 on the rotating side. A rotation sensor 10 is provided on the end surface opposite to the side where the seal member 7 is mounted.

[0051] The rotation side of the rotation sensor 10 includes an annular core 8 that is press-fitted and fixed to the outer diameter surface of one end of the inner ring 1, and a magnetic encoder 13 that is fixed to the outer diameter surface of the core 8. The metal core 8 is provided with a mounting portion 12 having an L-shaped cross section bent in the diameter-expanding direction at the outer end of the annular fixing portion 11, and the magnetic encoder 13 is mounted on the outer diameter surface of the mounting portion 12.

An annular member 32 serving as a fixed side of the rotation sensor 10 is press-fitted and fixed to the inner diameter surface of the outer ring 2. The annular member 32 is provided with a mounting portion 34 having an L-shaped cross section at the outer end of an annular fixing portion 33 for fitting to the inner diameter surface of the end portion of the outer ring 2, and the mounting portion 34 is It protrudes longer in the axial direction than the mounting part 12 of the core 8 on the inner ring 1 side.

Further, a magnetic bypass part 35 is provided on the inner end of the fixed part 33. The magnetic bypass portion 35 has an inclined portion 36 which is bent in a V shape with an inner end force of the fixed portion 33 having a certain angle α (see FIG. 8) and is inclined toward the outside of the bearing, and an end portion of the inclined portion 36 is It has a radial portion 37 that is bent in the direction of the inner ring 1 and formed in the radial direction. The fixed portion 33 and the inclined portion 36 form a V-shaped bent portion 38. As described above, the annular member 32 is a single part including the fixing portion 33, the mounting portion 34, and the bypass portion 35, and is processed by press molding.

Note that a bypass gap g2 is provided between the inner end of the radial portion 37 and the fixing portion 11 of the cored bar 8.

[0055] A sensor holder 19 made of annular grease or the like is attached to the inner surface of the mounting portion 34 of the annular member 32, and an electric circuit board embedded in a mold grease 40 in a part of the sensor holder 19 Plate 21 isotropic force S It is fixed together by insert molding. A-phase and B-phase magnetic sensors 28 and 29 mounted on the electric circuit board 21 are embedded in the sensor holder 19, and a part thereof is exposed on the inner peripheral surface of the sensor holder 19, and is attached to the magnetic encoder 13. Oppose each other with the required gap.

[0056] An L-shaped annular side plate member 23 is coupled to the outer periphery of the mounting portion 34 of the annular member 32. For this connection, force squeeze portions 39 are provided at several places on the entire circumference, so that reliable contact at the abutting portion between the mounting portion 34 and the side plate member 32 and a required coupling force can be obtained. The side plate member 32 covers the outer end surface and the inner diameter surface of the sensor holder 19, and further faces the fixed portion 11 inner diameter surface of the core metal 8 via a predetermined circuit gap g 1. An axial encoder gear g3 is provided between the magnetic encoder 13 and the magnetic bypass part 35.

[0057] The annular member 32, the side plate member 23, and the cored bar 8 are formed of magnetic stainless steel sheet metal (thin plate), and are each processed by press molding. A magnetic circuit is formed by these members, the circuit gap g1, the bypass gap g2, and the encoder gap g3.

Now, as shown in FIG. 10, when the leakage flux Φ enters the outer ring 2, the leakage flux Φ is divided into leakage fluxes Φ 1 and Φ 2, and the inner ring 1 passes through the following two magnetic circuits. To.

That is, the magnetic circuit through which the leakage flux Φ 1 passes is the circuit from the outer ring 2 → the mounting part 34 → the side plate member 23 → the core metal 8 → the inner ring 1 and the side plate member 23 → the circuit gap gl → the magnetic shield. It is a circuit that goes from 1 to 13 → Encoder gap ₈ 3 → Radial part 37 → Bypass gap g2 → Fixed part 11 → Inner ring 1.

Further, the magnetic circuit through which the leakage flux Φ 2 passes is a circuit extending from the outer ring 2 → the bypass part 35 (the inclined part 36 → the radial direction part 37) → the bypass gap g 2 → the fixed part 11 → the inner ring 4.

[0061] The leakage flux Φ that has entered the outer ring 2 passes through the bearing through the magnetic circuit as described above, thereby exerting a shielding effect on the magnetic sensors 28 and 29, and the detection accuracy of the magnetic sensors 28 and 29 is high. Maintained. In particular, due to the presence of the V-shaped bent portion 38, the path of the leakage magnetic flux Φ 2 passes through a portion further away from the magnetic sensors 28 and 29, so that the shielding effect is enhanced.

Claims

The scope of the claims

[1] An inner ring, an outer ring, and a plurality of rolling elements interposed between the inner ring and the outer ring, wherein one of the inner ring and the outer ring is defined as a rotating side race ring, and the other is defined as a fixed side race ring. A magnetic encoder in which magnetic poles of different polarities are alternately formed at a constant pitch in the circumferential direction is mounted on a metal core attached to the raceway, and an annular member attached to the stationary raceway is opposed to the magnetic encoder. A bearing with a rotation sensor equipped with a magnetic sensor, wherein the magnetic material of the magnetic encoder is a rare earth magnetic material, and fluorine rubber is used as a binder.

2. The bearing with a rotation sensor according to claim 1, wherein the rare earth-based magnetic material is a samarium-based material.

[3] The bearing with a rotation sensor according to [1] or [2], wherein the rare earth magnetic material is kneaded into a fluorine rubber material.

[4] An inner ring, an outer ring, and a plurality of rolling elements interposed between the inner ring and the outer ring, wherein one of the inner ring and the outer ring is defined as a rotating side race ring, and the other is defined as a fixed side race ring. A magnetic encoder in which magnetic poles of different polarities are alternately formed at a constant pitch in the circumferential direction is mounted on a metal core attached to the raceway, and an annular member attached to the stationary raceway is opposed to the magnetic encoder. A magnetic sensor is attached, and one end portion of the side plate member integrated with the tip end portion of the annular member is opposed to the inner diameter surface of the core metal through a predetermined circuit gap, and the inner end portion of the annular member is magnetized. A magnetic circuit including the annular member, the side plate member, the circuit gap, and the cored bar by making the outer peripheral edge of the bypass part integral and bringing the inner peripheral edge closer to the cored bar through a predetermined bypass gap; The magnetic bike In rotation sensor equipped bearing by forming a bypass magnetic circuit also scan unit and the bypass gap force, the rotation sensor with bearings and the annular member and the magnetic bypass portion is characterized in that it is constituted by a single part.

5. The bearing with a rotation sensor according to claim 4, wherein the annular member is made of magnetic stainless steel.

[6] The annular member includes an annular part and a bypass part, and the annular part has a fixing part fitted to the stationary-side raceway, and the bypass part is constant from an inner end of the fixing part of the annular part. And an inclined portion bent in a V shape toward the outside of the bearing, and a radial portion formed by bending the end of the inclined portion in the radial direction, and the inner peripheral edge of the radial portion is the aforementioned The bearing with a rotation sensor according to claim 4 or 5, wherein the bypass gap is formed with a cored bar.