JP2002228675A - Encoder and rolling bearing unit having the encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the area of a section where water possibly adheres, out of slingers 17a that function as a core bar, and to increase the distance between an edge section that easily discharge electricity and an adhesive surface. SOLUTION: The outer diameter of a circular wheel section 23a for composing the slinger 17a is set larger than that of an encoder body 22 that is a permanent magnet, and at the same time a bent edge section 32 is formed at the outer-periphery end section of the circular wheel section 23a. With this configuration, the area and distance are secured and the problem is solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The encoder according to the present invention is used in a state of being incorporated in a rolling bearing unit for rotatably supporting a wheel of an automobile with respect to a suspension device.
Then, by combining a rolling bearing unit with an encoder incorporating the encoder and a sensor, the rotation speed of the wheel supported by the rolling bearing unit is detected.

[0002]

2. Description of the Related Art In addition to supporting the wheels of a vehicle rotatably with respect to a suspension, an anti-lock brake system (ABS) and a traction control system (TC) are provided.
In order to detect the rotational speed of the wheel in order to control S), various types of rolling bearing units with encoders are known. When the rotational speed of the wheel is detected magnetically, an encoder whose magnetic characteristics alternate (generally at regular intervals) in the circumferential direction is used as the encoder. As described above, an encoder using a permanent magnet in which S poles and N poles are alternately arranged in the circumferential direction as an encoder whose magnetic characteristics alternately change in the circumferential direction simplifies the structure on the sensor side and has a low speed. In order to secure the detection accuracy at the time, the frequency of use has increased in recent years.

An encoder made of a permanent magnet used for the above-mentioned applications is formed entirely of a magnetic metal plate such as carbon steel, stainless steel or the like into an annular shape (including an annular shape and a cylindrical shape, and the entire shape is formed into a circular annular shape). (The same applies throughout this specification.)
A permanent magnet such as a rubber magnet or a plastic magnet is adhered to a part of the mandrel formed over the entire circumference (including a case where the rubber magnet is baked on the mandrel with a primer interposed therebetween. Same as above). That is, a permanent magnet such as a rubber magnet or a plastic magnet in which ferromagnetic powder such as ferrite is mixed in rubber or synthetic resin is adhered and fixed to a part of the annular mandrel. S poles and N poles are alternately arranged on the surface of the permanent magnet in the circumferential direction. For this reason, the magnetization direction of this permanent magnet is
Alternating in the circumferential direction.

FIG. 5 shows a first example of a conventional structure of a rolling bearing unit 1 for supporting wheels incorporating such an encoder. In the case of the first example, the rotating wheel is connected to the hub 2.
Axial middle or inner end of
Refers to the center in the width direction when assembled to the vehicle.
Right. Conversely, the left side in FIGS. 5 and 8, which is outward in the width direction when assembled to the vehicle, is referred to as outside. ) And a pair of inner rings 3, 3
Are externally fitted. The hub 2 has a flange 4 for supporting and fixing the wheel at the outer end of the outer peripheral surface, a spline hole 5 at the center, and the inner ring 3,
Inner ring raceways 6, 6 are provided on the outer peripheral surface of 3, respectively. A spline shaft 34 provided on the constant velocity joint 7 is inserted into the spline hole 5. The nut 9 is screwed into the male screw 8 provided at the outer end of the spline shaft 34 and further tightened. Then, the inner end of the housing 10 provided at the inner end of the spline shaft 34 is The inner end surface of the inner ring 3 is held down, and the pair of inner rings 3 is fixed to the hub 2.

On the other hand, an outer ring 11, which is a stationary wheel, is disposed around a rotating wheel composed of the hub 2 and the inner rings 3, 3. The outer ring 11 is fitted and fixed inside a cylindrical bearing case 12 so that the bearing case 12 can be supported and fixed to a suspension device (not shown). Also, on the inner peripheral surface of the outer race 11, the inner raceway 6, which is provided on the outer peripheral surface of each of the inner races 3, 3,
6 are provided with outer raceways 13, 13, respectively. A plurality of rolling elements 14, 14 are respectively held between the outer raceways 13, 13 and the inner raceways 6, 6 by the retainers 15, 15 so as to freely roll. Provided. The outer ring 11
Sealing devices 16 and 16a are respectively mounted between the inner peripheral surfaces of both ends of the inner ring and the outer peripheral surfaces of the ends of the inner rings 3 and 3 to shut off the internal space where the rolling elements 14 and 14 are installed from the outside. ,
The grease existing in the internal space is prevented from leaking, and foreign matter is prevented from entering the internal space.

As shown in detail in FIG. 6, each of the sealing devices 16 and 16a has a slinger 17 and a seal ring 18 respectively.
And a combination seal ring is used. The slinger 17 is made of a magnetic metal plate such as a carbon steel plate such as SPCC and has an L-shaped cross section and is formed in an annular shape. The slinger 17 is externally fixed to an end of each of the inner rings 3 and 3 by interference fitting. I have. The seal ring 18 is formed by attaching a resilient material 20 to a mandrel 19 formed of a metal plate having an L-shaped cross section and having an annular shape as a whole, with an elastic member 20 attached over the entire circumference. The inner ring 19 is tightly fitted to both ends of the outer ring 11 by tight fitting so that the inner ring 19 is fixed to both ends of the outer ring 11. In this state, the leading edges of the plurality of seal lips 21 provided on the elastic member 20 are attached to the slinger 17.
Each is in sliding contact over the entire circumference.

[0007] Of the above sealing devices 16 and 16a, an encoder main body 22 is attached to the inner surface of a slinger 17 constituting the inner sealing device 16a over the entire circumference to form an encoder. are doing. Therefore, the slinger 17 corresponds to a mandrel described in claims. The encoder body 22 is a permanent magnet such as a rubber magnet or a plastic magnet in which ferromagnetic powder such as ferrite is mixed in rubber or synthetic resin, and is magnetized in the axial direction. The magnetization directions are changed alternately and at equal intervals in the circumferential direction. Therefore, on the side surface of the encoder body 22,
The S pole and the N pole are alternately arranged in the circumferential direction. Such an encoder body 22 is provided with the slinger 17.
Are supported and fixed to the inner surface of the annular portion 23 provided by the adhesive. The inner diameter of the encoder main body 22 in the free state is smaller than the inner diameter of the cylindrical portion 24 provided on the slinger 17 as shown in FIG. Accordingly, in a state where the cylindrical portion 24 is externally fitted and fixed to the end of the inner ring 3, the inner peripheral edge of the encoder body 22 elastically abuts on the outer peripheral surface of the end of the inner ring 3 over the entire circumference. , Seal this part. Therefore, foreign matter such as rainwater does not enter the fitting portion between the cylindrical portion 24 and the inner ring 3.

On the other hand, in a part of the bearing case 12 which protrudes inward from the inner end surface of the outer race 11, a mounting hole 2 is formed.
5 is formed so as to penetrate the bearing case 12 in the radial direction. A sensor 26 for detecting a rotational speed (see FIG. 8 described later; omitted in FIG. 5) can be attached to the mounting hole 25. The detection surface provided at the tip of the sensor 26 can be freely opposed to the encoder body 22 in the axial direction via a minute gap.

The encoder main body 22 constructed as described above
In the rolling bearing unit 1 incorporating the above, the outer ring 11 is connected and fixed to the suspension device by the bearing case 12, and the wheel is supported and fixed to the hub 2 by the flange 4. In this state, the wheels are rotatably supported by the suspension device. When the wheel rotates, the sensor 26
S and N poles present on the outer peripheral surface of the encoder main body 22 alternately pass near the detection surface of
Output signal changes. Since the frequency at which the output signal of the sensor 26 changes is proportional to the rotational speed of the wheel, if the output signal is sent to a controller (not shown), the rotational speed of the wheel is obtained, and the ABS or TCS is appropriately adjusted. Can control.

Next, FIG. 8 shows a second example of the conventional structure of a rolling bearing unit 1a for supporting wheels incorporating an encoder. In the case of the second example, the outer inner raceway 6 is formed directly on the outer peripheral surface of the intermediate portion of the hub 2a. The inner ring 3 is externally fixed to a small-diameter step portion 27 formed at the inner end of the hub 2a. An outer flange 11 is provided on the outer peripheral surface of the outer ring 11a, and the outer ring 11a is connected to the knuckle 2 which constitutes a suspension device.
9 (without any other members such as the bearing case 12). Further, of the pair of sealing devices 16 and 16b provided on the inner peripheral surfaces of both ends of the outer ring 11a, the inner sealing device 16 is a combination seal ring similar to that of the above-described first example, whereas the outer sealing device 16 is Is a single seal ring having no slinger.

In the case of this embodiment, a cylindrical surface 30 formed on the outer end of the housing 10 of the constant velocity joint 7 has
The encoder is externally fixed. This encoder is made of a magnetic metal plate and has an annular shape (short cylindrical shape) as shown in detail in FIG.
A rubber magnet encoder body 2 is provided on the outer peripheral surface of the mandrel 31.
2a is adhered over the entire circumference. The encoder main body 22a is magnetized in the diameter direction, and the magnetization directions are alternately changed at equal intervals in the circumferential direction. Therefore, S poles and N poles are alternately arranged in the circumferential direction on the outer peripheral surface of the encoder body 22a. A mounting hole 25a formed in a part of the knuckle 29
The detection surface of the sensor 26 inserted into the encoder body 22 is closely opposed to the outer peripheral surface of the encoder body 22a. In this case as well, the wheels can be rotatably supported by the suspension device, and the rotation speed of the wheels can be determined.

[0012]

As shown in FIGS. 5 and 8, in the case of a structure in which an encoder is provided so as to be exposed to an external space, an encoder body 2 constituting the encoder is used.
It has been found from the research of the present inventors that it is difficult to secure the durability of the bonded portion between the 2, 22a and the slinger 17 or the mandrel 31. Such a decrease in durability is caused by an adhesive based on the discharge at the slinger 17 or the mandrel 31 (including a primer for baking. The same applies to the entire specification).
It was also found from the study of the present inventor that it was due to the degradation or elution of. The mechanism of such adhesive deterioration or elution will be described below.

When moisture containing electrolyte, such as muddy water or salt water, adheres to the encoder, a local battery is formed between the encoder body 22 and the slinger 17 (or between the encoder body 22a and the mandrel 31) of different materials. You. Slinger 1
A local battery may be formed between the bearing 7 (or the mandrel 31) and other parts of the bearing device having different materials or peripheral components of the bearing device. Then, a discharge may occur based on a potential difference between the encoder main body 22 and the slinger 17 or a potential difference between the slinger 17 and the other component or the peripheral component. Due to such discharge, the encoder body 22 and the slinger 17 (or the encoder body 2
The adhesive bonding between the core body 2a and the mandrel 31 is deteriorated or eluted, and the encoder body 22 and the slinger 17 are peeled off (or the encoder body 22a and the mandrel 31).

Further investigations by the present inventor have shown that the extent of the discharge is limited to the portion of the slinger 17 (or mandrel 31) that is not covered by the encoder body 22 (22a), and that the moisture adheres to. It was found that the discharge was substantially inversely proportional to the surface area, in other words, the smaller the surface area, the more remarkable the discharge. Further, it was also confirmed that the discharge was remarkable at the sharp edge portion of the slinger 17 (or the mandrel 31).

On the premise of the findings made by the inventor's research, the conventional encoder shown in FIGS. 7 and 9 shows that the encoder main body 22 of the slinger 17 (or the mandrel 31) is included. The surface area of a portion where moisture is likely to adhere without being covered by (22a) is small. In addition, an edge portion existing in a part of the slinger 17 (or the mandrel 31) is adjacent to an end of an adhesion surface between the slinger 17 (or the mandrel 31) and the encoder body 22 (22a) ( An edge is located at the edge of the bonding surface). For this reason, peeling of the bonding surface may proceed from the edge toward the center with the discharge.

In order to prevent the adhesive surface between the slinger 17 (or the mandrel 31) and the encoder body 22 (22a) from being separated due to the above-described causes and to improve the durability of the encoder, the slinger 17 is used. (Or the mandrel 31), the surface area of a portion to which moisture is likely to adhere without being covered by the encoder body 22 (22a) is increased,
It is considered effective to increase the distance between the edge surface existing in a part of the metal 7 (or the mandrel 31) and the bonding surface.
The encoder and the rolling bearing unit with the encoder of the present invention have been invented in view of such circumstances.

[0017]

In the encoder and the rolling bearing unit with the encoder according to the present invention, the encoder according to claim 1 is formed in an annular shape like the above-mentioned conventionally known encoder. On one side of the mandrel,
It is formed by bonding permanent magnets which are annular and whose magnetization directions are alternately changed in the circumferential direction. In particular, in the encoder according to the first aspect, by making the width of the mandrel larger than the width of the permanent magnet, at least one end of the mandrel protrudes from one end of the permanent magnet. Let me.

A rolling bearing unit with an encoder according to a second aspect of the present invention also has a stationary wheel having a stationary side raceway, similarly to the above-described rolling bearing unit with an encoder.
A rotating wheel having a rotating side track, and a plurality of rolling elements rotatably provided between the stationary side track and the rotating side track,
A part of the rotating wheel exposed to the external space includes an encoder supported concentrically with the rotating wheel. This encoder is the encoder according to the first aspect.

[0019]

In the encoder of the present invention constructed as described above, one end of the mandrel is protruded from one end of the permanent magnet, and a part of the mandrel is covered by the permanent magnet. Therefore, the surface area of a portion to which moisture may adhere without contact increases, and the distance between the edge portion existing in a part of the mandrel and the bonding surface increases. For this reason, even if the water containing the electrolyte adheres to a part of the mandrel, it becomes difficult for electric discharge to occur, and
Even if a discharge occurs at the edge portion, the discharge hardly deteriorates the adhesive existing on the bonding surface between the mandrel and the permanent magnet.

[0020]

1 and 2 show a first embodiment of the present invention. In the case of this example, the slinger 17a, which is the core metal described in the claims, is formed by bending a magnetic metal plate such as a carbon steel plate such as SPCC or a stainless steel plate, thereby forming the circular ring portion 23a and the cylindrical portion 24. And the whole is formed in an annular shape with an L-shaped cross section. In particular, in the case of the present example, the outer diameter of the ring portion 23a is set to the value shown in FIGS.
And the radial direction of the encoder body 22, for example, is larger than the outer diameter of the encoder body 22, which is a permanent magnet, which is adhered and fixed to the inner surface of the annular portion 23a. Is larger than 1/10 of the width dimension. An outer diameter portion of the circular ring portion 23a projects radially outward from an outer peripheral edge of the encoder body 22. Further, in the case of this example, the bent edge portion 32 is formed by bending the outer peripheral edge portion of the circular ring portion 23a outward over the entire circumference. As in the case of the first example of the conventional structure, the encoder main body 22 is magnetized in the axial direction, and the magnetization directions are alternately changed at equal intervals in the circumferential direction.

The slinger 17a and the encoder body 22 are combined with a seal ring 18 as shown in FIG. 2 to form a sealing device 16c which is a combined seal ring, as shown in FIG. The inner end opening of the rolling bearing unit 1 having the structure is sealed. That is,
The cylindrical portion 24 of the slinger 17a is externally fitted and fixed to the inner end of the inner ring 3 constituting the rolling bearing unit 1, and a mandrel 19 constituting the seal ring 18.
Is fixedly fitted inside the inner end of the outer race 11. Then, the seal lip 2 of the elastic material 20 constituting the seal ring 18 is formed.
The leading edges of the first and the first 21 are brought into sliding contact with the outer peripheral surface of the cylindrical portion 24 constituting the slinger 17a and the inner surface of the annular portion 23a over the entire circumference. Further, the outer peripheral surface or the distal end edge of the bent edge portion 32 is closely opposed to the inner peripheral surface of the mandrel 19 to the elastic member 20 constituting the seal ring 18 to form a labyrinth seal in this portion.

The encoder and the rolling bearing unit with the encoder according to the present embodiment, which are configured as described above, are combined with a sensor in the same manner as the first example of the conventional structure shown in FIGS. The rotation speed of the wheel fixed to the flange 4 is detected. In particular, in the case of the encoder of the present example, the outer peripheral edge of the slinger 17a, which is a cored bar, is projected radially outward from the outer peripheral edge of the encoder main body 22, which is a permanent magnet. The surface area of the portion close to the outer diameter to which moisture is likely to adhere without being covered by the encoder main body 22 is increased. In addition, the distance between the edge portion existing on the outer peripheral edge of the slinger 17a and the bonding surface increases.

Particularly in the case of this embodiment, the slinger 17a
Since the bent edge portion 32 is formed on the outer peripheral edge of the annular portion 23a, the distance between the edge portion and the bonding surface can be sufficiently increased. That is, the ring portion 23a is simply
When the outer diameter of the ring is increased, the outer peripheral edge of the annular portion 23a and the inner peripheral surface of the mandrel 19 forming the seal ring 18 interfere with each other. To increase the distance between the edge portion and the bonding surface without forming the bent edge portion 32, the outer diameter of the encoder body 22 must be reduced. On the other hand, by bending the bent edge 32, the outer diameter of the encoder body 22 is ensured, and the interference between the annular portion 23a and the mandrel 19 is prevented. The distance between the edge portion and the bonding surface can be increased. Ensuring the outer diameter of the encoder main body 22 ensures the strength of the magnetic flux generated from the encoder main body 22 and can contribute to the improvement of the performance of the rotation speed detecting device. Since the bent portion that connects the annular portion 23a and the bent edge portion 32 is not as sharp as the edge portion, discharge is unlikely to occur at the outer peripheral portion of the bent portion.

As described above, since the surface area of the portion to which moisture may adhere is widened, even if moisture containing an electrolyte adheres to a part of the mandrel, electric discharge does not easily occur.
Also, because the distance between the edge and the bonding surface is increased,
Even if a discharge occurs at the edge portion, the discharge does not easily deteriorate the adhesive existing on the bonding surface between the inner surface of the annular portion 23a and the encoder body 22.

FIG. 3 shows a second embodiment of the present invention.
An example is shown. In the case of this example, as in the second example of the conventional structure shown in FIG. 8 described above, an encoder that is externally fitted and fixed to the cylindrical surface portion 30 formed on the outer end of the housing portion 10 of the constant velocity joint 7 includes: The case where the present invention is applied is shown. The encoder of this example assembled to such a part
An encoder main body 22a made of a rubber magnet is adhered to the entire outer circumference of an annular (short cylindrical) core metal 31a made of a magnetic metal plate. The encoder main body 22a is magnetized in the diameter direction, and the magnetization directions are alternately changed at equal intervals in the circumferential direction.

Particularly, in the case of the encoder of this embodiment, the axial width W ₃₁ of the mandrel 31 a is sufficiently (for example, 1.5 times) larger than the axial width W _{22 of the} encoder body 22 a. Above) (W ₃₁ ≧ 1.5
And W ₂₂₎ and. Then, the encoder main body 22a
Is adhered to the outer peripheral surface of the center part in the width direction (axial direction) of the mandrel 31a. Therefore, the bonding surface between the outer peripheral surface of the intermediate portion of the mandrel 31a and the inner peripheral surface of the encoder body 22a can be sufficiently separated from the edge portions present at both end edges of the mandrel 31a (the width dimension of the encoder body 22a). more than a quarter of the W ₂₂₎ away.

The encoder of the present embodiment as described above is assembled with, for example, the structure of the second example of the conventional structure shown in FIG. 8 so that the rotational speed of the wheel rotating together with the hub 2a can be detected. In the case of the encoder of this example, the above-mentioned mandrel 31a is used.
Is increased so that the surface area of the outer peripheral surfaces and both end portions of the core 31a, which are not covered by the encoder body 22a and to which moisture may adhere, is increased. Even if moisture containing an electrolyte adheres to a part of the battery, electric discharge does not easily occur. In addition, since the distance between the edge portions existing at both end edges of the mandrel 31a and the bonding surface is large, even if a discharge occurs at this edge portion, the discharge is generated between the outer peripheral surface of the middle portion of the mandrel 31a and the bonding surface. The adhesive existing on the bonding surface with the inner peripheral surface of the encoder main body 22a is not easily deteriorated.

FIG. 4 shows a third embodiment of the present invention.
An example is shown. In the case of this example, a cylindrical mandrel 31b
Are bent radially outward to form outwardly flanged bent edges 33, 33. With this configuration, the width W of the mandrel 31b in the axial direction is obtained.
Without increasing the size of ₃₁ ', the surface area of the portion to which moisture may adhere and the distance between the edge portion and the bonding surface are ensured. For this reason, the width dimension of the mounting portion of the encoder can be reduced. In addition, the both bent edges 33, 3
3 spacing D ₃₁ between, said mandrel 31b (for example 1.2 times or more) sufficiently than the width W ₂₂ in the axial direction of the encoder main body 22a that is bonded to the intermediate outer peripheral surface of the larger (W ₃₁ ≧ 1.2W ₂₂₎ to have. Therefore, the above mandrel 31
bonding surface between the inner peripheral surface of b of the intermediate portion outer peripheral surface and the encoder main body 22a is first width dimension W ₂₂ of the from the inner surfaces of the bent edges 33, 33, sufficiently (encoder main body 22a
/ 10 or more). In addition, each of the bent edges 33, 3
3 height H _33, the thickness T of the encoder main body 22a ₂₂
(H ₃₃ <T ₂₂ ). The reason for this is that the outer peripheral surface of the encoder body 22a is
This is for making the encoder main body 22a easily magnetize by projecting radially outward from the outer peripheral edge of the encoder 33. Other configurations and operations, such as a state of being assembled to the rolling bearing unit 1a, are the same as in the case of the above-described second example.

[0029]

Since the encoder and the rolling bearing unit with the encoder according to the present invention are constructed and operated as described above, sufficient durability can be ensured even when the encoder is exposed to the external space.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of an encoder, showing a first example of an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a state in which a sealing device is configured by combining the encoder with a seal ring.

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

FIG. 4 is a partial sectional view showing the third example.

FIG. 5 is a sectional view showing a first example of a conventionally known rolling bearing unit with an encoder.

FIG. 6 is an enlarged view of a part A of FIG.

FIG. 7 is a partial cross-sectional view showing only an encoder.

FIG. 8 is a cross-sectional view showing a second example of a conventionally known rolling bearing unit with an encoder.

FIG. 9 is a partial cross-sectional view showing only an encoder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Rolling bearing unit 2, 2a Hub 3 Inner ring 4 Flange 5 Spline hole 6 Inner ring raceway 7 Constant velocity joint 8 Male screw part 9 Nut 10 Housing part 11, 11a Outer ring 12 Bearing case 13 Outer ring raceway 14 Rolling element 15 Cage 16, 16a, 16b, 16c Sealing device 17, 17a Slinger 18 Seal ring 19 Mandrel 20 Elastic material 21 Seal lip 22, 22a Encoder main body 23, 23a Ring portion 24 Cylindrical portion 25, 25a Mounting hole 26 Sensor 27 Small diameter step portion 28 Mounting Part 29 Knuckle 30 Cylindrical surface part 31, 31a, 31b Mandrel 32 Bending edge 33 Bending edge 34 Spline shaft

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F16C 33/76 F16C 33/76 A

Claims (2)

[Claims] 1. An encoder in which a permanent magnet whose annular magnetization direction is alternately changed with respect to a circumferential direction is bonded to one surface of a ring-shaped cored bar, wherein the width of the permanent magnet is An encoder characterized in that at least one end of the mandrel is made to protrude beyond one end of the permanent magnet by making the width of the mandrel larger than that of the permanent magnet. 2. A stationary wheel having a stationary track, a rotating wheel having a rotating track, a plurality of rolling elements rotatably provided between the stationary track and the rotating track, and A rolling bearing unit with an encoder, comprising an encoder concentrically supported by the rotating wheel on a portion of the wheel exposed to the external space, wherein the encoder is the encoder according to claim 1.