JP2000055928A - Rolling bearing unit with encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of rotary speed detection by increasing the change of magnetic characteristics in the circumference direction of a part that opposes a magnetic detection element at one portion of the circular ring part for composing an encoder. SOLUTION: Inside edges 29a and 29a in the circumference direction of through holes 9a and 9a being provided at a circular ring part 8 of an encoder 6a are set in nearly parallel to the diameter direction of the circular ring part 8, thus making equal width dimensions W28a of post parts 28a and 28a being provided between the through holes 9a and 9a over the nearly total length of the post parts 28a and 28a. Furthermore, the width dimensions W28a of the post parts 28a and 28a can be sufficiently reduced. Then, the width dimensions W28a of the post parts 28a and 28a is regulated so that the width dimensions are set to 0.8-1.1 times the thickness T8 of a magnetic metal plate for constituting the circular ring part 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A rolling bearing unit with an encoder according to the present invention rotatably supports, for example, wheels of an automobile with respect to a suspension system, or has a housing in which a rotating shaft constituting an automatic transmission for an automobile is mounted. For example, a rotating part constituting various mechanical devices is rotatably supported with respect to a fixed part, and is used for detecting a rotation speed of the rotating part.

[0002]

2. Description of the Related Art For example, in the case of an automobile, it is necessary to detect the rotation speed of wheels to appropriately control an antilock brake system (ABS) and a traction control system (TCS). On the other hand, in the case of an automatic transmission for a vehicle, it is necessary to detect the rotation speed of the rotating shaft in order to determine the timing of switching. For this reason, rotating parts such as wheels and rotating shafts constituting such various mechanical devices are
Rolling bearing units with a rotation speed detection device for rotatably supporting a fixed portion such as a suspension device or a housing that does not rotate even during use and detecting the rotation speed of this rotating portion have been widely used in the past. I have.

FIG. 1 shows a first example of an embodiment of the present invention, which will be described later, with respect to an example of the structure of a rolling bearing unit with a rotation speed detecting device conventionally used for such a purpose. The conventional structure of the encoder 6 incorporated in the rolling bearing unit with the rotation speed detecting device will be described with reference to FIG. An outer raceway 2 which is a stationary side raceway is formed on the inner peripheral surface of the outer race 1 which is a stationary wheel. On the outer peripheral surface of the inner ring 3 which is a rotating wheel, an inner ring track 4 which is a rotating side track is formed. Between the outer raceway 2 and the inner raceway 4, a plurality of balls 5, each of which is a rolling element, are provided so as to roll freely.
The inner ring 3 is rotatably supported on the inner diameter side of the inner ring 3.

[0004] An encoder 6 is externally fitted and fixed to the outer peripheral surface of the end of the inner ring 3. The encoder 6 is made of a magnetic metal plate such as a mild steel plate and has an L-shaped cross section and is formed in an annular shape. The encoder 6 includes a fixed cylindrical portion 7 and one end edge (the left end edge in FIG. And a ring portion 8 bent outward in the diametric direction. The annular portion 8 has slit-shaped through holes 9, 9, each of which is a thinned portion, and is long in the diameter direction.
Are formed at equal intervals in the circumferential direction to form a large number of pillar portions 28, 28, each of which is a solid portion, between the circumferentially adjacent through holes 9, 9. I have. Then, the magnetic characteristics of the ring portion 8 are changed alternately at regular intervals in the circumferential direction. The through holes 9 are formed by punching the annular portion 8 by pressing.

On the other hand, the base end (the right end in FIG. 1) of the sensor housing 10 is externally fitted and fixed to the outer peripheral surface of the end of the outer race 1. The sensor housing 10 includes a cover 11 made of a metal plate and a holding ring 12 made of a synthetic resin held inside the cover 11. Cover 11 of these
Is formed in the shape of a ring with a crank-shaped cross section.
A fitting tube portion 14 is formed on the outer peripheral edge of the butting plate portion 13 formed near the outer diameter, and a holding portion 15 is formed on the inner peripheral edge. The fitting tube portion 14 is fitted around a small-diameter step portion 16 formed on the outer peripheral surface of the end of the outer ring 1 by interference fit, and the abutment plate portion 13 is attached to the outer ring 1.
The cover 11 is fixedly connected to the outer race 1 in a state where it abuts against the end surface of the outer ring 1.

The holding section 15 has an L-shaped cross section and is formed in an annular shape as a whole. A part of the holding portion 15 in the circumferential direction is swelled in the axial direction to form a storage portion 17. In the holding section 15 including the storage section 17,
A holding ring 12 made of synthetic resin is held and fixed. And
The sensor 18 is embedded and supported in a portion of the holding ring 12 located in the storage section 17. This sensor 1
As 8, a magnetic detecting element 19, which is preferably a Hall element or a magnetoresistive element, a permanent magnet (not shown) for flowing a magnetic flux passing through the magnetic detecting element 19, and an output signal of the magnetic detecting element 19 are processed. And an active type processing circuit not shown. This processing circuit is an IC or an LSI, and includes a waveform shaping circuit for adjusting the waveform of the magnetic detection element 19, an amplifier circuit for amplifying the output of the waveform shaping circuit, and determining whether a failure has occurred. And a self-diagnosis circuit.

In a state where the sensor housing 10 supporting the sensor 18 as described above is fixedly connected to the end of the outer ring 1, the detecting portion of the sensor 18 is a circular portion which is a detected portion of the encoder 6. 8 through a minute gap extending in the thrust direction. Specifically, as shown in FIG. 5, the magnetic detecting element 19 is disposed at a position facing the center of each of the through holes 9 and 9 and the pillars 28 and 28 in the diametrical direction of the ring 8. are doing. Further, the harness 20 for extracting the detection signal of the sensor 18 is connected to the holding portion 15 from the circumferential end surface of the lead-out portion 21 provided at a position separated from the storage portion 17 at a part of the holding portion 15. It is derived almost parallel to one side.

When the above-described rolling bearing unit with a rotation speed detecting device is used, the outer ring 1 is internally fitted and fixed to a fixed portion such as the housing 22. In the illustrated example, the abutment plate 13 provided on the outer peripheral edge of the cover 20 is connected to the locking flange 23 formed on the inner peripheral surface of the housing 22 and one end surface of the outer ring 1 (the left end surface in FIG. 1). ).
A locking groove 24 formed on the inner peripheral surface of the housing 22
In addition, a ring-shaped retaining ring 25 called a C-ring is locked to hold down the other end surface (the right end surface in FIG. 1) of the outer ring 1. With this configuration, the outer race 1 is supported and fixed at a predetermined position in the housing 22. Further, the inner ring 3 is externally fitted and fixed to an intermediate portion of the rotating shaft 26. In this state, one end surface of the inner ring 3 is abutted against a step 27 formed on the outer peripheral surface of the rotating shaft 26.

When the inner ring 3 rotates in this state, the detecting portion of the sensor 18, for example, the magnetic detecting element 1 is formed.
9, the through holes 9, 9 provided in the circular ring portion 8 of the encoder 6 and the column portions 28, 28 existing between the circumferentially adjacent through holes 9, 9 alternately pass through. I do. As a result,
The density of the magnetic flux flowing in the magnetic detecting element 19 changes,
The output of the sensor 18 changes. Thus, the sensor 18
Is proportional to the rotational speed of the inner ring 3. Therefore, this output signal is transmitted to the harness 20.
By sending the signal to a controller (not shown) via the controller, the rotation speed of the rotating part can be known.

Incidentally, in order to improve the accuracy of the rotation speed detection by the rolling bearing unit with such a rotation speed detecting device, the amount of change in the magnetic characteristics of the circular ring portion 8 constituting the encoder 6 in the circumferential direction is required. It is effective to increase the output of the magnetic detection element 19 by increasing
In order to increase the output of the magnetic detection element 19,
In order to increase the amount of change in the magnetic characteristics of the circular ring portion 8 in the circumferential direction, the portion of the circular ring portion 8 facing the magnetic detection element 19 should have the circumferential shape of the through holes 9, 9. It is preferable to increase the width in the direction, and to reduce the width in the circumferential direction of each of the pillars 28 formed between the through holes 9.

[0011]

However, in the case of the encoder 6 incorporated in the conventional structure as described above, the magnetic characteristics in the circumferential direction of a portion of the circular ring portion 8 where the magnetic detecting element 19 faces. It is difficult to make the amount of change large enough. The reason is as follows. That is, in the case of the above-described conventional structure, as shown in FIG. 5, the shape of each of the through holes 9 formed in the annular portion 8 is rectangular, that is, the shape of the through holes 9 in the circumferential direction of the annular portion 8 is different. Both inner edges 29 of each through hole 9, 9,
29 are parallel to each other. In other words, the width dimension of each of the through holes 9 is uniform from the inner diameter side to the outer diameter side of the annular portion 8 (except for the R portion formed at the corner portion). For this reason, the respective column portions 28 in the circumferential direction of the circular ring portion 8,
The width dimension of 28 decreases as it goes inward in the diameter direction of the ring portion 8. For this reason, in order to sufficiently reduce the width of each of the pillars 28, 28 at the portion facing the magnetic sensing element 19, the width of each of the through holes 9, 9 in the circumferential direction should be sufficiently large. , The above-mentioned pillars 28, 2
The width dimension of the portion near the inner diameter of 8 is too small. As a result, the width dimension of each of the through holes 9 in the circumferential direction cannot be made sufficiently large, and the width dimension of each of the pillar portions 28, 28 at the portion where the magnetic detection element 19 faces is made sufficiently small. Can not. In addition, as the width of each of the pillars 28, 28 is sufficiently reduced in the portion where the magnetic detection element 19 is opposed, the width of each of the pillars 28, 28 near the inner diameter is too small. When forming the through holes 9 in the circular ring portion 8 by stamping with a press, the inconvenience that the portions of the column portions 28 near the inner diameter are twisted or cut off. Occurs. For this reason, it is not possible to sufficiently increase the change in the magnetic properties in the circumferential direction of the part of the circular ring portion 8 facing the magnetic detection element 19.

Further, as described above, the inconvenience that the change in the magnetic characteristics in the circumferential direction of the portion of the circular ring portion 8 facing the magnetic detection element 19 cannot be made sufficiently large constitutes an encoder. A large number of notches are formed at the peripheral edge of the circular ring portion at the same interval in the circumferential direction. That is, in this case, the width dimension of the tongue pieces, which are formed between the notches adjacent in the circumferential direction, each of which is a solid portion, increases toward the outside in the diametrical direction, and the inner end in the diametrical direction. When the width dimension of the portion is set to a size that can prevent twisting during press working, the width dimension of the tongue piece in the longitudinal direction, which is the portion where the magnetic sensing element 19 faces, is sufficiently small. Can not. In view of the above-described circumstances, the rolling bearing unit with the encoder of the present invention is designed to increase a change in magnetic characteristics in a circumferential direction of a portion of the annular portion of the encoder facing the magnetic detection element. It was invented.

[0013]

A rolling bearing unit with an encoder according to the present invention has a stationary-side track on a stationary-side peripheral surface and does not rotate during use, similarly to the above-described conventional rolling bearing unit with an encoder. A wheel, a rotating-side track on a rotating-side circumferential surface opposed to the stationary-side circumferential surface, and a rotatable wheel that rotates during use, and a rotatably provided between the stationary-side track and the rotating-side track. A plurality of rolling elements, and an encoder supported on the rotating wheel concentrically with the rotating wheel. The encoder has an annular portion made of a magnetic metal plate, and a plurality of thinned portions are formed on the annular portion at regular intervals in the circumferential direction, and each thinned portion adjacent in the circumferential direction is formed. By forming a solid portion between the portions, the magnetic characteristics of the annular portion are changed alternately at regular intervals in the circumferential direction. In particular, in the rolling bearing unit with the encoder according to the present invention, both inner edges of each of the thinned portions in the circumferential direction of the annular portion are formed substantially parallel to the diametric direction of the annular portion. Accordingly, the width of each of the solid portions in the circumferential direction of the annular portion is made equal in the diametrical direction of the annular portion, and the width of each of the solid portions is set to be the same as that of the magnetic material forming the annular portion. 0.8-thickness of metal plate thickness
It is regulated to 1.1 times.

[0014]

According to the rolling bearing unit with the encoder and the sensor of the present invention having the structure described above, the rotating part such as the rotating shaft can be replaced with the part which does not rotate even when the housing or the like is used. On the other hand, the rotation bearing unit is rotatably supported, and the operation of detecting the rotation speed of the rotating portion is the same as that of the above-described conventional rolling bearing unit with a rotation speed detection device. In particular, in the case of the rolling bearing unit with the encoder of the present invention, the width dimension of each enriched portion formed on the circular ring portion of the encoder in the circumferential direction is made substantially equal over the entire length of each enriched portion, and this width is also made equal. The dimensions are small enough. For this reason, the magnetic field in the circumferential direction of a portion of the circular portion facing the detecting portion of the sensor (the central portion of each of the enriched portion and the thinned portion with respect to the diameter direction of the circular portion). Changes in characteristics can be made sufficiently large.

[0015]

1 and 2 show a first embodiment of the present invention. The feature of this example is that the shape of the through-holes 9a, 9a formed in the annular portion 8 of the encoder 6a, each of which is a thinned portion, is devised so that the annular portion 8 can be formed.
Is to increase the change of the magnetic characteristics in the circumferential direction. Since the structure and operation of the other parts are as described above (as described with reference to FIG. 1 of the present example), duplicate description will be omitted or simplified, and the following description will focus on the characteristic parts of the present invention. I do.

In the case of this embodiment, both inner edges 29a, 29a of the respective through holes 9a, 9a in the circumferential direction of the annular portion 8 are provided.
Are formed substantially parallel to the diametrical direction of the circular ring portion 8 (corresponding to the central portion of each column portion 28a, 28a). That is, in the case of this example, the shape of each of the through holes 9a, 9a is not a rectangle but a trapezoid or a sector. Accordingly, in the case of the present example, the pillars 28a, 28a formed between the circumferentially adjacent through holes 9a, 9a, which are solid portions, are The width W _28a in the circumferential direction is made equal over substantially the entire length of each of the pillars 28a, 28a except for a portion corresponding to the R portion of the corner. In the case of this example, each of these pillars 28
The width W _28a of the a
In order to increase the change of the magnetic characteristics in the circumferential direction of the column portions 28a, the width dimension W _{28a of} each of the column portions _28a {FIG. 2 (B)}.
The thickness T ₈ of the magnetic metal plate forming the circular ring portion ₈
{0.8 to 1.1 times of FIG. 2A} W _28a = (0.8
1.1) T ₈ ｝.

The reason why the width W _28a is restricted to the above range is as follows. That is, this width dimension W _28a
Is smaller than the above range (W _28a <0.8T ₈ ), when forming the through holes 9a, 9a in the annular portion 8 by punching with a press, the column portions 28 are formed.
This is because a and 28a may be twisted or broken. Furthermore, during the punching process, an excessive surface pressure is prevented from being applied to the dies supporting the circular ring portion 8, and the dies are prevented from being damaged. Conversely, the width dimension W _28a is larger than the above-mentioned range (W
_{When 28a} > 1.1T ₈ ), the width W _28a cannot be made sufficiently small while securing the thickness T ₈ in order to secure the rigidity of the circular ring portion _8, and thus the magnetic force is reduced. The change in characteristics cannot be increased.

In the case of the present embodiment constructed as described above, each column 28a, 28a formed on the circular ring 8 of the encoder 6a.
The width W _28a of the annular portion 8 in the circumferential direction is made substantially equal over the entire length, and the width W _28a is made sufficiently small. For this reason, a portion of the annular portion 8 where the magnetic detecting element 19 faces (the through holes 9a, 9a and the column portions 28 in the diameter direction of the annular portion 8).
a, the central part of 28a) can be sufficiently increased in the amount of change in magnetic properties in the circumferential direction. As a result, the output of the magnetic detection element 19 is increased, and the accuracy of rotation speed detection by the rotation speed detection device including the sensor 18 supported on the outer wheel 1 as a stationary wheel can be improved. The above sensor 1
8 does not necessarily need to be supported on a stationary wheel such as the outer ring 1. For example, when the present invention is applied to a rolling bearing unit for supporting wheels of an automobile, the sensor can be supported by a member other than the components of the rolling bearing unit, such as a knuckle forming a suspension device.

FIGS. 3 and 4 show a second embodiment of the present invention. In the case of this example, a large number of notches 30, 30 each of which is a thinned portion, are formed at equal intervals in the circumferential direction on the outer peripheral edge of the circular ring portion 8 constituting the encoder 6b. Notch 3 adjacent in the circumferential direction
A large number of tongue pieces 31, 31 each of which is a solid part, are formed between 0 and 30. The magnetic characteristics of the ring portion 8 are changed alternately and at equal intervals in the circumferential direction. In the case of the present example, both inner edges 29b, 2 of the respective notches 30, 30 in the circumferential direction of the annular portion 8 are provided.
9b are formed substantially parallel to the diameter direction of the ring portion 8. That is, in the case of the present example, the width dimension W ₃₁ of each of the tongue pieces 31, 31 in the circumferential direction of the circular ring portion 8 {FIG.
(B) is substantially equal over the entire length of each of the tongue pieces 31, except for the portion corresponding to the R portion of the corner.
Also in the case of this example, the width dimension W of each of these tongue pieces 31, 31 is also set.
₃₁ and smaller in order to increase the change of magnetic properties over the circumferential direction of the circular ring portion 8, the width W ₃₁ of the tongues 31, 31, magnetic metal constituting the circular ring portion 8 0.8-1.1 times the thickness of the plate T ₈ {FIG _{4 (a)} {W 31} = (0.
_{8 to} 1.1) T ₈規 制 is regulated.

Also in the case of the present embodiment constructed as described above, the width dimension W ₃₁ of each of the tongue pieces 31, ₃₁ in the circumferential direction of the circular ring portion 8 is set to substantially the entire length of each of the tongue pieces 31, 31. Can be made sufficiently small. For this reason, a portion of the circular ring portion 8 where the magnetic detecting element 19 which is the detection unit of the sensor 18 faces (the notches 3 in the diameter direction of the circular ring portion 8).
0, 30 and the central portion of each tongue piece 31, 31), the change of the magnetic properties in the circumferential direction can be made sufficiently large. As a result, the output of the magnetic detection element 19 is increased, and the accuracy of rotation speed detection by the rotation speed detection device including the sensor 18 can be improved. Other configurations and operations are the same as in the case of the above-described first example.

In each of the examples described above, the case where the rotating wheel is the inner wheel 3 has been described. However, the present invention can be applied even when the rotating wheel is the outer wheel 1. That is, when the rotating wheel is the outer wheel 1, the encoder 6a of each of the above-described examples,
6b, the inner and outer portions in the diametrical direction are reversed, and the encoders configured as described above are internally fitted and fixed to the end of the outer ring 1. In each example described above, the encoder 6
Although a and 6b have been described as being incorporated in a rolling bearing for rotatably supporting the rotating shaft 26 inside the housing 22, the present invention is not limited to this. For example, a rolling bearing unit for rotatably supporting a rotating portion constituting various mechanical devices with respect to a fixed portion, such as a rolling bearing unit for rotatably supporting a wheel of an automobile with respect to an axle or a suspension device. Can also be incorporated.

[0022]

Since the rolling bearing unit with encoder of the present invention is constructed and operates as described above, the change in the magnetic characteristics in the circumferential direction of the annular portion constituting the encoder is increased, and the rotational speed is increased. The accuracy of rotation speed detection by the detection device can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first example of an embodiment of the present invention.

FIG. 2 shows an encoder incorporated in the present example,
(A) is a partial cross-sectional view, (B) is a view seen from the left side of (A).

FIG. 3 is a sectional view showing a second example of the embodiment of the present invention.

FIG. 4 is a view similar to FIG. 2, showing an encoder incorporated in the present example.

FIG. 5 is a view similar to FIG. 2B, showing an example of a conventional structure.

[Explanation of symbols]

 Reference Signs List 1 outer ring 2 outer ring track 3 inner ring 4 inner ring track 5 ball 6, 6a, 6b encoder 7 fixed cylindrical portion 8 circular ring portion 9, 9a through hole 10 sensor housing 11 cover 12 holding ring 13 butting plate portion 14 fitting cylinder portion 15 Holding section 16 Small diameter step section 17 Storage section 18 Sensor 19 Magnetic detection element 20 Harness 21 Outgoing section 22 Housing 23 Locking flange section 24 Locking groove 25 Retaining ring 26 Rotating shaft 27 Step section 28, 28a Column section 29, 29a, 29b Inner edge 30 Notch 31 Tongue piece

Claims (1)

[Claims] 1. A stationary wheel having a stationary raceway on a stationary peripheral surface and not rotating during use, and a rotating raceway on a rotating peripheral surface opposed to the stationary peripheral surface and rotating during use. A rotating wheel, a plurality of rolling elements rotatably provided between the stationary-side track and the rotating-side track, and an encoder supported on the rotating wheel concentrically with the rotating wheel. The encoder has an annular portion made of a magnetic metal plate, and a plurality of thinned portions are formed on the annular portion at regular intervals in the circumferential direction, and the thinned portions adjacent to each other in the circumferential direction are formed. In a rolling bearing unit with an encoder, the magnetic characteristics of the annular portion are alternately and uniformly changed in the circumferential direction by forming a solid portion between the annular portions. Both inner edges of each of the above-mentioned thinned portions with respect to the circumferential direction are respectively substantially parallel to the diametrical direction of the ring portion. By forming the annular portion, the width of each solid portion in the circumferential direction of the annular portion is made equal in the diameter direction of the annular portion, and the width of each solid portion is formed in the annular portion. A rolling bearing unit with an encoder, characterized in that the thickness is 0.8 to 1.1 times the thickness of the magnetic metal plate.