JPH11183492A - Rolling bearing unit with rotational speed detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reliability of rotational speed detection by locating a rotation sensor for encoder higher than the central axis of a bearing unit thereby suppressing the fluctuation of gap between the encoder and the sensor. SOLUTION: A rolling bearing unit with a rotational speed detector being employed in control of automobile, or the like, comprises an encoder 23 having an annular permanent magnet bonded to a core metal 22 being secured to an inner ring 7a, and a sensor 4a held by a holder 26 disposed at a knuckle 24 for securing an outer ring 1. Detecting section of the sensor 4a is located at a specified position above the central axis of the unit while facing the encoder 23 through a microgap 27. According to the structure, dimensional shift of the gap 27 due to resilient deformation caused by application of a moment to a hub 2a can be suppressed at the time of quick turn of an automobile mounting the unit resulting in the stabilization of sensor 4a output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A rolling bearing unit with a rotation speed detecting device according to the present invention rotatably supports a wheel of an automobile with respect to a suspension device, and is used for detecting the rotation speed of the wheel.

[0002]

2. Description of the Related Art Rolling bearing units are used to rotatably support the wheels of an automobile with respect to a suspension system.
Further, in order to control an antilock brake system (ABS) or a traction control system (TCS), it is necessary to detect the rotation speed of the wheel. For this reason, the above-mentioned wheel is rotatably supported with respect to the suspension device by a rolling bearing unit with a rotation speed detecting device in which a rotation speed detecting device is incorporated in the above-mentioned rolling bearing unit, and the rotation speed of the wheel is detected. However, it has been widely practiced in recent years.

FIGS. 7 and 8 show an example of a conventional structure of a rotational speed detecting device used for such a purpose as disclosed in Japanese Patent Application Laid-Open No.
No. 96634 describes this. This rolling bearing unit with a rotation speed detecting device rotatably supports a hub 2 which is a rotating wheel which rotates during use inside an outer ring 1 which is a stationary wheel which does not rotate during use. The rotation speed of the fixed encoder 3 can be detected by a sensor 4 supported on the outer ring 1. That is, on the inner peripheral surface of the outer race 1, which is the stationary peripheral surface, double-row outer raceways 5, 5, each of which is the stationary raceway, are provided. The hub 2 is attached to the outer peripheral surface of the hub body 6 by 1
A pair of inner rings 7, 7 are fixed by external fitting. Inner ring raceways 8, 8, each of which is a rotation side raceway, are provided on the outer peripheral surfaces of both inner races 7, 7 each being a rotation side peripheral surface.
Then, each of these inner raceways 8, 8 and each of the outer raceways 5,
5, a plurality of rolling elements 9, 9 are provided rotatably while being held by retainers 10, 10, respectively, and the hub 2 is rotatably supported inside the outer ring 1. ing.

At the outer end of the hub body 6 (the outer end in the width direction when assembled to an automobile, the left end in FIG. 7), the hub protrudes axially from the outer end of the outer ring 1. The part is provided with a flange 11 for attaching a wheel. An inner end of the outer race 1 (an end which is located at the center in the width direction when assembled to an automobile, a right end in FIG. 7) is provided with a mounting portion 12 for mounting the outer race 1 to a suspension system.
Is provided. Further, a gap between the outer end opening of the outer race 1 and the outer peripheral surface of the intermediate portion of the hub 2 is formed by a seal ring 13.
It is closed by.

[0005] In order to incorporate the rotational speed detecting device into the rolling bearing unit as described above, a portion of the hub body 6 near the inner end and protruding inward from the inner rings 7, 7 is provided with:
The encoder 3 is externally fitted and fixed. The encoder 3 is formed entirely in a ring shape from a magnetic metal plate such as steel, and has a detected portion 14 provided on an inner side (right side in FIG. 7) near an outer periphery. Such an encoder 3 is mounted between the nut 15 screwed to the inner end of the hub main body 6 and the inner end surface of the inner inner ring 7 in a state of being externally fitted to a portion near the inner end of the hub main body 6. It is clamped and fixed to the hub 2. The detected portion 14 is formed with concavities and convexities extending in the circumferential direction, and the shape of the detected portion 14 is made into a gear shape. The magnetic characteristics of the detected portion 14 are alternately and equally spaced in the circumferential direction. Is changed.

Further, a bottomed cylindrical cover 16 is fitted and fixed to the inner end opening of the outer race 1 to close the inner end opening of the outer race 1. The cover 16, which is formed by plastically processing a metal plate, includes a fitting cylindrical portion 17 that can be fitted and fixed in the inner end opening of the outer race 1, and a closing plate portion 18 that closes the inner end opening.
And The sensor 4 is supported on a portion of the closing plate 18 near the outer periphery, and the tip end surface (the left end surface in FIG. 7) of the detection unit 19 of the sensor 4 is
Are opposed to each other with a small gap in the axial direction, for example, of about 0.5 mm.

In the case of the rolling bearing unit with the rotation speed detecting device as described above, the flange 11 provided at the outer end of the hub 2
To the suspension that supports the outer ring 1,
Can be rotatably supported. Also, with the rotation of the wheels, the hub 2
When the encoder 3 externally fitted and fixed to the inner end of the sensor 4 rotates, the vicinity of the end face of the detection unit 19 of the sensor 4
The convex portions and concave portions formed in 4 pass alternately. As a result, the density of the magnetic flux flowing in the sensor 4 changes, and the output of the sensor 4 changes. The frequency at which the output of the sensor 4 changes is proportional to the rotational speed of the wheel. Therefore, if the output of the sensor 4 is sent to a controller (not shown), ABS and T
CS can be controlled appropriately.

In order to ensure the reliability of the detection of the rotational speed of the wheel by the rolling bearing unit with the rotational speed detecting device configured and operating as described above, the tip end face of the detecting portion 19 of the sensor 4 and the encoder 3 It is necessary to stabilize the size of the minute gap between the inner surface of the detected portion 14 and the inner surface. On the other hand, each component of the rolling bearing unit is elastically deformed as the vehicle travels. In particular, when the automobile makes a sharp turn, the elastic deformation of each of the above-described components increases based on a moment load (due to turning acceleration) applied to the hub 2 from the wheels via the flange 11. Then, based on the increase in the amount of elastic deformation, the size of the minute gap changes. Such a change in the dimension itself may cause a change in the output of the sensor 4, and thus may impair the reliability of the rotation speed detection. For this reason, Japanese Patent Application Laid-Open No. 8-29
In the case of the invention described in Japanese Patent No. 6634, the sensor 4 is arranged on a horizontal plane passing through the center axis of the hub 2, so that the dimensional change of the minute gap can be changed regardless of the elastic deformation of the constituent members. And ensure the reliability of rotation speed detection.

[0009]

Problems to be Solved by the Invention Japanese Patent Application Laid-Open No. Hei 8-29663
In the case of the invention described in Japanese Patent Application Publication No. 4 (1999), only a part of the elastic deformation of each component based on the moment load applied to the hub 2 when the vehicle turns sharply is considered. For this reason, it is not possible to actually stabilize the size of the minute gap between the distal end surface of the detecting portion 19 of the sensor 4 and the inner surface of the detected portion 14 of the encoder 3. That is, in the rolling bearing unit based on the moment load, a displacement occurs in which the center axis of the outer ring 1 and the center axis of the hub 2 do not coincide with each other, and a displacement occurs in which the outer ring 1 and the hub 2 are displaced in the axial direction. I do. In the case of the invention described in JP-A-8-296634, the center shaft of the outer ring 1 and the hub 2
Only the displacement at which the center axis of the non-alignment does not coincide is considered. For this reason, even if the sensor 4 is actually arranged on a horizontal plane passing through the center axis of the hub 2, the dimension of the minute gap cannot be stabilized, and does not contribute much to securing the reliability of the rotation speed detection. The rolling bearing unit with a rotation speed detecting device of the present invention has been invented in view of such circumstances.

[0010]

A rolling bearing unit with a rotation speed detecting device according to the present invention has a stationary side track on a stationary side peripheral surface, similarly to the above-mentioned conventional rolling bearing unit with a rotation speed detecting device, A stationary wheel that does not rotate even during use, and has a rotating track on the rotating peripheral surface opposite to the stationary peripheral surface,
A rotating wheel that rotates during use, a plurality of rolling elements rotatably provided between the stationary-side track and the rotating-side track, and changing the characteristics in the circumferential direction alternately and at equal intervals. An encoder fixed to the rotating wheel concentrically with the rotating wheel, and a detecting portion, and the detecting portion is axially aligned with a part of the detected portion of the encoder. A sensor that is supported by a member that does not rotate during use in a state of facing the sensor, and that changes an output signal in response to a change in the characteristic of the detected part. In particular, in the rolling bearing unit with the rotation speed detecting device of the present invention, the position of the detection unit of the sensor in the circumferential direction of the stationary wheel and the rotating wheel is a position above the respective central axes.

Further, in the rolling bearing unit with the rotation speed detecting device according to the second aspect, the acceleration in the horizontal direction accompanying the turning of the vehicle in a state where the rolling bearing unit with the rotation speed detecting device is on the outside. When (+ 1G) occurs, the inclination angle between the center axis of the stationary wheel and the center axis of the rotating wheel is θ _1, and the relative displacement of these stationary wheel and rotating wheel in the axial direction is δ _a1. When the radius of the detected part of the encoder is r, δ _a1 ≧ r · θ ₁ , and the position of the detecting part of the sensor is located above the central axis and on a vertical line passing through the central axis. The position is almost the same as the position.

Further, in the rolling bearing unit with the rotation speed detecting device according to the third aspect, the acceleration in the horizontal direction accompanying the turning of the vehicle in a state where the rolling bearing unit with the rotation speed detecting device is on the outside. When (+ 1G) occurs, the inclination angle between the center axis of the stationary wheel and the center axis of the rotating wheel is θ _1, and the relative displacement of these stationary wheel and rotating wheel in the axial direction is δ _a1. Assuming that the radius of the detected portion of the encoder is r, δ _a1 ≦ r · θ ₁ , and the acceleration and the above-mentioned acceleration are accompanied by the turning of the vehicle in a state where the rolling bearing unit with the rotation speed detecting device is inside. When an acceleration of the same magnitude and in the opposite horizontal direction (−1 G) is generated, the inclination angle between the center axis of the stationary wheel and the center axis of the rotating wheel is θ ₂ , Axial relative displacement with the wheel It was a [delta] _a2, the radius of the detected portion of the encoder when the r, a _{δ a2 ≦ r · θ 2,} ψ 1, the [psi ₂ is the angle relative to the horizontal axis passing through the respective central axes, [psi _{When 1} = sin ⁻¹ (δ _a1 / r · θ ₁ ) and ψ ₂ = sin ⁻¹ (δ _a2 / r · θ ₂ ), the position of the detection unit of the sensor with respect to the stationary wheel is determined. , Ψ ₁ and ψ ₂
And almost at the middle position.

[0013]

With the rolling bearing unit with the rotation speed detecting device of the present invention configured as described above, the wheel is rotatably supported with respect to the suspension device, and the operation when detecting the rotation speed of the wheel is as described above. This is the same as the conventional structure described above. In particular, in the case of the rolling bearing unit with the rotation speed detecting device of the present invention, the center axis of the stationary wheel and the center axis of the rotating wheel become inconsistent based on the moment load applied when the vehicle turns sharply, Even when the stationary wheel and the rotating wheel are displaced in the axial direction, it is possible to reduce the deviation of the dimension of the gap in the axial direction existing between the detected part of the encoder and the detection part of the sensor. As a result,
Irrespective of the elastic deformation of each component of the rolling bearing unit based on the moment load, the output of the sensor is stabilized and the reliability of the rotation speed detection can be improved. Since the detected part of the encoder and the detection part of the sensor are opposed in the axial direction, it is not necessary to consider the deformation in the radial direction due to the external load.

[0014]

1 and 2 show a first embodiment of the present invention. The hub 2a, which is a rotating wheel, is formed by connecting and fixing a hub body 6a and an inner ring 7a. A flange 11 for mounting and fixing wheels is provided on an outer peripheral surface of an outer end portion (left end portion in FIG. 1) of the hub main body 6a, and a double-row inner ring is provided on an outer peripheral surface of the hub 6a on an intermediate outer peripheral surface. Tracks 8a, 8b
Of these, the outer inner raceway 8a is formed, and a small-diameter stepped portion 20 is formed at the inner end (right end in FIG. 1). The inner ring 7a is fixed to the inner end of the hub main body 6a by fitting the outer ring to the step portion 20 and further expanding the inner end of the hub main body 6a outward in the diameter direction. On the outer peripheral surface of such an inner ring 7a, the inner inner raceway 8 of the inner row of multiple rows of inner raceways 8a and 8b provided on the outer peripheral surface of the hub 6a is provided.
b is provided. And these two inner raceways 8a, 8b
A plurality of rolling elements 9, 9 are provided between a plurality of rows of outer raceways 5, 5 provided on the inner peripheral surface of the outer race 1 which is a stationary wheel.
And the hub 2 a is rotatably supported inside the outer ring 1. Although balls are used as the rolling elements 9 in the illustrated example, tapered rollers may be used as these rolling elements in the case of a heavy-duty rolling bearing unit of an automobile.

An outer end opening of the outer ring 1 and the hub 2
The gap between the outer peripheral surface of the middle portion of the inner ring 7a is closed by a seal ring 13 and the gap between the inner end opening of the outer ring 1 and the outer peripheral surface of the inner end of the inner ring 7a is closed by a combined seal ring 21. I have. An encoder 23 is attached to an inner surface of a cored bar 22 which is fitted and fixed to the inner end of the inner ring 7a. The encoder 23 formed entirely of a permanent magnet in a ring shape is magnetized in the axial direction (the left-right direction in FIG. 1). The magnetization directions are changed alternately at regular intervals in the circumferential direction. Therefore, S poles and N poles are alternately arranged at equal intervals on the inner surface of the encoder 23 which is the detected part.

The outer race 1 is attached and fixed to a knuckle 24 which is a non-rotating part of the suspension device by an outward flange-shaped attachment portion 12 formed on the outer peripheral surface of the inner end portion. Also, a mounting hole 25 provided in a part of the knuckle 24 is provided.
, A holder 26 holding the sensor 4a is inserted, and the detection unit of the sensor 4a is attached to the inner surface of the encoder 23.
They face each other with a small gap 27 of about 0.5 mm extending in the axial direction. In this state, the holder 26
It is fixed to the knuckle 24 by a screw 28.

In particular, in the case of the rolling bearing unit with the rotation speed detecting device of the present invention, the mounting position of the sensor 4a is determined by the rigidity of the rolling bearing unit portion composed of the outer ring 1, the hub 2a and the rolling elements 9, 9. Therefore, the following regulations. Incidentally, when it is assumed that an acceleration of +1 G is generated based on the turning when the vehicle equipped with the rolling bearing unit with the rotation speed detecting device turns while the rolling bearing unit with the rotating speed detecting device is outside. The relative displacement of the outer race 1 and the hub 2a in the axial direction is δ _a1 . Further, when the vehicle turns with the rolling bearing unit with the rotation speed detecting device inside, when the acceleration of -1G is generated based on the turning, the outer ring 1 and the hub 2a are assumed. Δ _a2 is the relative displacement amount in the axial direction. Further, when it is assumed that the acceleration of +1 G is generated,
The angle of inclination (radian) between the central axis of the outer race 1 and the central axis of the hub 2a is defined as θ ₁ . On the other hand, the above-mentioned -1G
Is assumed to be θ ₂ , the inclination angle (radian) between the central axis of the outer race 1 and the central axis of the hub 2 when it is assumed that the above acceleration occurs. Further, the radius of the detected part of the encoder 23 is r. The radius r of the detected part is
The distance from the center axis of the hub 2a to the center in the width direction (diameter direction) of the portion of the inner surface of the encoder 23 facing the sensor 4a. Under these conditions, if δ _a1 ≧ r · θ ₁ (and simultaneously δ _a2 ≧ r · θ ₂ ), the installation position of the sensor 4a in the circumferential direction of the outer ring 1 and the hub 2a is changed. , These outer ring 1 and hub 2
The position is located above the central axis of “a” and substantially coincides with a vertical line passing through each of these central axes. That is, FIG.
, The intersection angle (radian) の between the chain line b representing the horizontal line and the chain line b representing the center line of the mounting hole 25 is represented by π /
Let it be 2. On the other hand, when δ _a1 ≦ r · θ ₁ and δ _a2 ≦ r · θ ₂ , the mounting position is the installation position of the sensor 4a in the circumferential direction of the outer ring 1 and the hub 2a. Intersecting angle 鎖 between a chain line b representing the center line of the hole 25 and a chain line a representing the horizontal line.
Is an intermediate position between ψ ₁ and ψ ₂ represented by the following equations (1) and (2). ψ ₁ = sin ⁻¹ (δ _a1 / r · θ ₁ ) −−− (1) ψ ₂ = sin ⁻¹ (δ _a2 / r · θ ₂ ) −−− (2) Incidentally, the sensor 4a is actually installed. When determining the position, it is not necessary to strictly satisfy the above conditions. Even at a position deviated from these conditions by about ± 15,
Is less likely to deviate to a practical problem.

The rolling bearing unit with the rotation speed detecting device of the present embodiment configured as described above rotatably supports the wheel with respect to the suspension device. This is the same as the rolling bearing unit with a rotation speed detecting device known from U.S. Pat. That is, when the hub 2a rotates together with the wheels, and the encoder 23 supported by the hub 2a rotates, the S pole and the N pole alternately pass near the detecting portion of the sensor 4a. As a result, the flow direction of the magnetic flux in the sensor 4a changes alternately, and the output of the sensor 4a changes. The frequency at which the output of the sensor 4a changes in this way is proportional to the rotational speed of the wheel. Therefore, if the output of the sensor 4a is sent to a controller (not shown), the ABS and TCS can be appropriately controlled.

In particular, in the case of the rolling bearing unit with the rotation speed detecting device of the present invention, the center axis of the outer ring 1 and the center axis of the hub 2a are adjusted based on the moment load applied when the automobile turns sharply. Even if the outer ring 1 and the hub 2a are displaced in the axial direction, the size of the minute gap 27 in the axial direction, which exists between the inner surface of the encoder 23 and the detection unit of the sensor 4a. The displacement can be reduced. As a result, based on the moment load, the components of the rolling bearing unit, that is, the outer ring 1 and the hub 2a, and the rolling elements 9, 9
Irrespective of the elastic deformation, the output of the sensor 4a is stabilized, and the reliability of the rotation speed detection can be improved.

Next, by satisfying the above conditions,
The reason why the dimensional deviation of the minute gap 27 can be kept small irrespective of the elastic deformation of each component of the rolling bearing unit will be described with reference to FIGS. 3 (A) and 3 (B) out of these FIGS.
That is, when δ _a1 ≧ r · θ ₁ , the small gap 27
FIG. 4 is a schematic diagram for explaining the reason why the dimensional deviation can be reduced.

First, referring to FIG.
According to (A) and (B), at the same time as δ _a1 ≧ · θ _1, δ _a2 ≧ r ·
The case where θ ₂ is described. When the vehicle makes a sharp turn, the outer ring 1 and the hub 2a and the rolling elements 9 and 9 are elastically deformed based on a moment load applied to the hub 2a from the wheels via the flange 11 by turning acceleration.
Then, the dimension of the minute gap 27 existing between the detected part of the encoder 23 supported and fixed to the hub 2a and the detection part of the sensor 4a supported by the knuckle 24 changes. For example, + 1G is attached to the hub 2a.
When the moment load is applied, as shown in FIG. 3A, the center axis of the outer ring 1 and the center axis of the hub 2a are
At the same time by the angle theta ₁ shifts on the vertical plane, these outer ring 1
And the hub 2a is over in the axial direction, it shifted by δ _a1. The angle θ ₁ and the deviation δ _a1 in the axial direction can be obtained by a conventionally known calculation formula for the bearing rigidity of a double-row rolling bearing.

As the center axis of the outer ring 1 and the center axis of the hub 2a are shifted by an angle θ ₁ , the size of the minute gap 27 decreases by r · θ ₁ at the upper end position of the minute gap 27, It tends to increase only r · θ ₁ at the lower end position. On the other hand, when the outer race 1 and the hub 2a extend in the axial direction, δ
Along with _a1 only shift it, the size of the small clearance 27 will tend to increase by over [delta] _a1 the entire periphery. When the moment load is applied, the size of the minute gap 27 is obtained by combining the displacement based on the displacement of the central axis and the displacement in the axial direction. Therefore, when δ _a1 ≧ r · θ ₁ , the displacement amount of the minute gap 27 is δ _a1 −r · θ ₁ at the upper end of the minute gap 27 and δ _a1 + r · θ at the lower end.
It becomes ₁ . At the center in the up-down direction, _Δa1 is obtained.

On the other hand, when a moment load of -1 G is applied to the hub 2a, as shown in FIG. 3B, the center axis of the outer ring 1 and the center axis of the hub 2a are vertical. at the same time by an angle theta ₂ shifts on the surface, the outer race 1 and the hub 2a is over the axial direction, in a direction opposite to the case of applied moment load of + 1G, shifted by [delta] _a2.
As the center axis of the outer ring 1 is shifted from the center axis of the hub 2a by an angle θ ₂ , the size of the minute gap 27 increases by r · θ ₂ at the upper end position of the minute gap 27 and at the lower end position. It tends to decrease only r · θ _2. On the other hand, the outer ring 1 and the hub 2a is over the axial direction, with the possible shifted by [delta] _a2, the dimensions of the small clearance 27, over the entire periphery [delta] _a2
Only tends to decrease. Therefore, when δ _a2 ≧ r · θ ₂ , the displacement amount of the minute gap 27 is
7 is δ _a2 −r · θ ₂ at the upper end and δ _a2 + r at the lower end.
· Θ ₂ become. At the center in the vertical direction, _Δa2 is obtained.
From these, δ _a1 ≧ r · θ ₁ at the same time δ _a2 ≧ r · θ is the displacement of the small clearance 27 is smallest when the _two are seen to be the upper end position.

Next, according to FIGS. 4A and 4B, δ _a1 ≦ r
A case where δ _a2 ≦ r · θ ₂ at the same time as θ ₁ will be described. First, when a +1 G moment load is applied to the hub 2a, as shown in FIG. 4A, the amount of displacement of the minute gap 27 becomes δ _a1 − at the upper end of the minute gap 27.
r · θ ₁ and δ _a1 + r · θ ₁ at the lower end. However, when δ _a1 ≦ r · θ ₁ , the outer ring 1 and the hub 2 a
And the displacement δ _a1 in the axial direction cancel each other due to the displacement of the central axes of the two, and there are two points in the circumferential direction where the displacement of the minute gap 27 becomes zero. . The center of the minute gap 27 (= the center of the radius r of the detected part of the encoder 23 = the center axis of the outer ring 1 and the hub 2a)
The distance in the vertical direction up to this point and r ₁ from the case where the crossing angle between the line and the horizontal line connecting this point and the center was a [psi _1, an _{r 1 = δ a1 / θ 1} , ψ 1 = sin ^-1 (r ₁ /
r) = sin ⁻¹ (δ _a1 / r · θ ₁ ). If the detection section of the sensor 4a and the detection section of the encoder 23 are opposed to each other in such a point that the above condition is satisfied, the small gap 2 can be obtained regardless of the moment load of +1 G applied during traveling.
7 can be kept from changing.

Next, when a moment load of -1 G is applied to the hub 2a, as shown in FIG. 4B, the displacement amount of the minute gap 27 becomes δ at the upper end of the minute gap 27. _a2 -r · _{θ 2,} and becomes the δ _a2 + r · _{θ 2} at the lower end. Then, at a point where the distance in the vertical direction from the center of the minute gap 27 is r ₂ , the displacement caused by the displacement of the center axes of the outer ring 1 and the hub 2 a and the displacement δ _{a2 in the} axial direction are offset. Accordingly, the displacement of the minute gap 27 is zero.
Becomes If the crossing angle between the line and the horizontal line displacement as the connecting point and the center becomes zero and the ψ _2, ψ ₂ = sin ^-1
(R ₂ / r) = sin ⁻¹ (δ _a2 / r · θ ₂ ). If the detection section of the sensor 4a and the detection section of the encoder 23 are opposed to each other in such a point that the above conditions are satisfied, the size of the minute gap 27 can be obtained regardless of the -1G moment load applied during traveling. Can be kept unchanged. The moment load during driving of the automobile, since the join ± directions in accordance with a running state of the automobile, the installation position of the sensor 4a in the circumferential direction of the outer ring 1 and the hub 2a, [psi ₁ and [psi
Intermediate position {Preferably, the position angle with respect to a horizontal line (radian) becomes _{(ψ 1 + ψ 2) /} 2} and ₂ if the,
Regardless of which direction the moment load is applied, it is possible to ensure the reliability of detecting the rotational speed of the wheel by the sensor 4a. As the condition for regulating the installation position of the sensor 4a, the magnitude of the acceleration (lateral G) is set to 1G because the maximum value of the acceleration applied to a general automobile (passenger car) is adopted. It is. That is, it is considered that the displacement of the minute gap 27 is suppressed under the condition in which the displacement of the minute gap 27 is most remarkable in a conceivable use state.

FIG. 5 shows a second embodiment of the present invention.
An example is shown. In the case of this example, the outer ring 1 which is a stationary wheel
5 is closed by a cover 16a. The cover 16a includes a bottomed cylindrical main body 29 formed by injection molding of a synthetic resin, and a fitting cylinder 30 coupled to an opening of the main body 29. This fitting cylinder 30
It is formed by plastically deforming a corrosion-resistant metal plate such as a stainless steel plate and has an L-shaped cross section, and is entirely annular. The fitting tube portion 31 and the base edge of the fitting tube portion 31 (right end in FIG. 5) And an inward flange 32 bent diametrically inward from the edge). Such a fitting cylinder 30 is connected to the opening of the main body 29 by molding the inward flange 32 during the injection molding of the main body 29. The cover 16a configured in this manner is formed by fixing the fitting tube portion 31 of the fitting tube 30 to the inner end portion of the outer ring 1 by external fitting with an interference fit.
The inner ring opening of the outer ring 1 is closed.

The main body 29 constituting the cover 16a
A portion of the bottom plate portion 33 which faces the inner surface of the encoder 23a which is externally fitted and fixed to the inner end of the inner ring 7a constituting the hub 2a which is a rotating wheel protrudes inward from the bottom plate portion 33. A cylindrical portion 34 is formed. Also, this cylindrical portion 34
The inner end face of the cylindrical portion 34 and the bottom plate portion 33
An insertion hole 35 communicating with the outer surface of the outer race 1 is formed in the axial direction of the outer race 1 (the left-right direction in FIG. 5). And
Into the insertion hole 35, a portion near the tip of the sensor unit 36 in which the sensor is embedded in a holder 26a made of synthetic resin is inserted. When the sensor unit 36 is inserted into the insertion hole 35 in this manner, the distal end surface of the sensor unit 36 is connected to the inner surface of the encoder 23, which is the detection target, via the minute gap 27 extending in the axial direction. opposite. Note that the sensor unit 36 as described above is attached to the cover 1.
In this case, in order to facilitate and quickly perform the work of attaching and detaching to and from the 6a, the cylindrical portion 34 and the locking flange 37 formed at the base end (the right end in FIG. 5) of the holder 26a A coupling spring 38 formed by bending a wire having elasticity and corrosion resistance, such as stainless spring steel, is provided between them. The coupling spring 38 presses the locking flange 37 toward the opening end surface of the cylindrical portion 34. However,
Since this part is not a main part of the present invention, a detailed description is omitted. The point that the mounting position of the sensor unit 36 with respect to the cover 16a is regulated is the same as in the case of the first example described above.

Next, FIG. 6 shows a third embodiment of the present invention.
An example is shown. In each of the first and second examples described above, the present invention is applied to a rolling bearing unit with a rotation speed detecting device for supporting a driven wheel (a rear wheel of an FF vehicle, a front wheel of an FR vehicle and an RR vehicle) of a vehicle on a suspension device. In contrast to the case where the present invention has been applied, the present embodiment is provided with a rotation speed detecting device for supporting the driving wheels of the vehicle (the front wheels of the FF vehicle, the rear wheels of the FR and RR vehicles, and all the wheels of the 4WD vehicle) on the suspension device. The present invention is applied to a rolling bearing unit. For this reason, in the case of the rolling bearing unit with the rotation speed detecting device of the present embodiment, the hub 2b as the rotating wheel is formed in a cylindrical shape, and the female spline portion 39 is formed on the inner peripheral surface of the hub 2b. I have. And this female spline part 39
In addition, a drive shaft (not shown) having a male spline portion formed on the outer peripheral surface can be freely inserted.

An encoder 23 is provided on a combination seal ring 21 for closing a gap between an inner peripheral surface of an inner end of an outer ring 1 which is a stationary wheel and an outer peripheral surface of an inner end of an inner ring 7a constituting the hub 2b. The point at which the sensor 4a is attached and fixed to the knuckle 24 to be supported and fixed, and the point at which the attachment position of the sensor 4a is regulated are the same as those in the first example described above. still,
A feature of the present invention resides in that the size of the minute gap existing between the detected part of the encoder and the detection part of the sensor is suppressed from changing due to sudden turning of the automobile or the like. The structure of the rolling bearing unit and the structures of the encoder and the sensor are not limited to those shown in the figures, and various conventionally known structures can be adopted. For example, a rolling bearing unit in which the inner ring side is a stationary wheel and the outer ring side is a rotating wheel can be an object of the present invention.

[0030]

The rolling bearing unit with the rotation speed detecting device of the present invention is constructed and operates as described above, so that the output of the sensor can be stabilized and the reliability of detecting the rotation speed of the wheel can be improved.

[Brief description of the drawings]

FIG. 1A shows a first example of an embodiment of the present invention,
-OA sectional drawing.

FIG. 2 is a view showing a main part and corresponding to a BB cross section of FIG. 1;

3A and 3B are diagrams for explaining displacement of a minute gap when a relatively small moment load is applied to the rigidity of the rolling bearing unit. FIG. 3A illustrates a case where a load in a + direction is applied. (B) is a schematic diagram when a load in the negative direction is received.

4A and 4B are diagrams for explaining displacement of a minute gap when a relatively large moment load is applied to the rigidity of the rolling bearing unit. FIG. 4A illustrates a case where a load in a + direction is applied. (B) is a schematic diagram when a load in the negative direction is received.

FIG. 5 is a view similar to FIG. 1, showing a second example of the embodiment of the present invention;

FIG. 6 is a view similar to FIG. 1, showing the third example.

FIG. 7 is a sectional view showing an example of a conventional structure.

FIG. 8 is a cross-sectional view taken along the line CC of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer ring 2, 2a, 2b Hub 3 Encoder 4, 4a Sensor 5 Outer ring track 6, 6a Hub main body 7, 7a Inner ring 8, 8a, 8b Inner ring track 9 Rolling element 10 Cage 11 Flange 12 Mounting part 13 Seal ring 14 Detected Part 15 Nut 16, 16 a Cover 17 Fitting cylindrical part 18 Blocking plate part 19 Detecting part 20 Step part 21 Combination seal ring 22 Core bar 23, 23 a Encoder 24 Knuckle 25 Mounting hole 26, 26 a Holder 27 Micro gap 28 Screw 29 Body 30 Fitting tube 31 Fitting tube portion 32 Inward flange portion 33 Bottom plate portion 34 Cylindrical portion 35 Insertion hole 36 Sensor unit 37 Locking flange portion 38 Coupling spring 39 Female spline portion

Claims (3)

[Claims] 1. A stationary wheel having a stationary raceway on a stationary peripheral surface and not rotating even during use, and a rotating raceway on a rotary 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 a ring-like shape in which the characteristics in the circumferential direction are alternately changed at equal intervals. A state in which an encoder having a detected part and fixed to the rotating wheel concentrically with the rotating wheel, and a detecting part, wherein the detecting part is opposed to a part of the detected part of the encoder in an axial direction In a rolling bearing unit with a rotation speed detection device, which is supported by a member that does not rotate even during use, and has a sensor that changes an output signal in response to a change in the characteristic of the detected part,
A rolling bearing unit with a rotation speed detecting device, wherein a position of a detecting portion of the sensor in a circumferential direction of the stationary wheel and the rotating wheel is a position above the respective central axes. 2. A center axis of a stationary wheel and a center axis of a rotating wheel when a horizontal acceleration is generated along with the turning of the vehicle with the rolling bearing unit with the rotation speed detecting device on the outside. the tilt angle and theta _1, the relative displacement over the axial direction of these stationary ring and the rotating ring and [delta] _a1, the radius of the detected portion of the encoder when the r, δ _a1 ≧ r
The rotation speed detecting device according to claim ₁ , wherein θ1 is set, and the position of the detection unit of the sensor is set to a position above the central axis and substantially coincident with a vertical line passing through the central axis. Rolling bearing unit. 3. The center axis of a stationary wheel and the center axis of a rotating wheel when a horizontal acceleration is generated with the turning of the vehicle with the rolling bearing unit with the rotation speed detecting device on the outside. the tilt angle and theta _1, the relative displacement over the axial direction of these stationary ring and the rotary ring and the [delta] _a1, the radius of the detected portion of the encoder when the r, δ _a1 ≦ r
· Theta _1, with the turning of the vehicle in a state where the speed sensing rolling bearing unit is inside, in the case where the horizontal direction of the acceleration of the same size as the acceleration occurs, the stationary ring the inclination angle between the center axis of the central shaft and the rotating ring and theta ₂ of the relative displacement over the axial direction of these stationary ring and the rotating ring and [delta] _a2, the radius of the detected portion of the encoder and r In this case, δ _a2 ≦ r · θ ₂ , and ψ ₁ and ψ ₂ are angles with respect to a horizontal axis passing through each of the above central axes, and ψ ₁ = sin ⁻¹ (δ _a1 / r · θ ₁ ). In addition, when ψ ₂ = sin ⁻¹ (δ _a2 / r · θ ₂ ), the positions of the detection unit of the sensor with respect to the stationary wheel are ψ ₁ and ψ.
_{2. The} rolling bearing unit with a rotation speed detecting device according to claim 1, wherein the rolling bearing unit is located substantially at an intermediate position between the rolling bearing unit and the rolling bearing unit.