JP2000291650A - Rolling bearing unit with encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reconcile both of the miniaturization of an axial dimension and the improvement of the output of a sensor 27. SOLUTION: An encoder is formed into the shape of a single cylinder as a whole by directly connecting both axial ends of a first cylindrical part 17 capable of mounting a part to be detected 38 and a second cylindrical part 18 capable of fitting and fixing an inner ring 10, having the same diameter. The axial dimension of the whole encoder 16 can be reduced for the omission of a ring part and the like for forming a stepped part between the first and second cylindrical parts 17, 18, while ensuring the axial dimension of the part to be detected 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A rolling bearing unit with an encoder according to the present invention supports, for example, a rotating shaft constituting an automatic transmission for an automobile and detects the rotational speed of the rotating shaft. Use in a state where it is built into the machine.

[0002]

2. Description of the Related Art A rolling bearing unit with an encoder is used to rotatably support a rotating shaft constituting an automatic transmission for an automobile inside a casing and detect a rotating speed of the rotating shaft. Such a rolling bearing unit with an encoder includes a rolling bearing for rotatably supporting the rotary shaft inside the casing, and a support and fixed to an inner ring, which is a rotating ring, of an inner ring and an outer ring constituting the rolling bearing. Encoder.

When such a rolling bearing unit with an encoder is used, the inner ring, which is a rotating wheel, is externally fixed to the rotating shaft, and the outer ring, which is a stationary wheel, is internally fixed to the casing. Further, a detection unit of a sensor supported on a portion which does not rotate even when the outer ring or the casing is used during use is opposed to a detected portion of the encoder. When the encoder rotates together with the rotation shaft in this state, the output of the sensor changes. The frequency at which the output of this sensor changes is proportional to the rotation speed of the rotating shaft. Therefore,
If the frequency of this sensor is input to the controller through a harness derived from this sensor, the rotation speed of the rotating shaft can be detected. The switching timing of the automatic transmission and the like can be obtained from the rotation speed of the rotating shaft detected in this manner.

As a specific structure of the above-described rolling bearing unit with an encoder, Japanese Patent Laid-Open Publication No. Hei 4-25613 describes a structure incorporating an encoder 1 as shown in FIG. This encoder 1 which is externally fitted and supported on the end of an inner ring which is a rotating wheel is formed into an annular shape with a crank-shaped cross section by subjecting a magnetic metal plate such as a mild steel plate to pressing, bending and the like. . That is, such an encoder 1 has a large-diameter cylindrical portion 2 corresponding to the first cylindrical portion in the claims.
And a small-diameter cylindrical portion 3 also corresponding to the second cylindrical portion of the claims.
And a circular ring portion 4 that connects the edges of the cylindrical portions 2 and 3 to each other. The axial direction of the large-diameter cylindrical portion 2 (FIG. 5)
In the middle part, a number of slit-shaped through-holes 5, each of which is a thinned part, which are long in the axial direction, are formed at equal intervals in the circumferential direction so that they are adjacent to each other in the circumferential direction. A large number of pillar portions 6 each of which is a solid portion are formed between the through holes 5. Thus, a detected part 38 whose magnetic properties change alternately and at regular intervals in the circumferential direction is provided at an intermediate part in the axial direction of the large-diameter cylindrical part 2. In the case of the rolling bearing unit with the encoder described in the above-mentioned publication, the large-diameter cylindrical portion 2 is fixed to the end of the inner ring while the small-diameter cylindrical portion 3 is fixedly fitted to the end of the inner ring (and the outer ring). From the axial direction. The reason why the encoder is assembled in such a state is to prevent the large-diameter cylindrical portion 2 from interfering with a plurality of rolling elements constituting a rolling bearing.

[0005]

However, in the case of a conventional rolling bearing unit with an encoder incorporating the encoder 3 as described above, there are the following problems. That is, in the case of a rolling bearing unit with an encoder incorporated in a space where installation space is limited, such as the inside of a casing constituting an automatic transmission for an automobile, while there is a demand to reduce the dimension in the axial direction, There is also a demand for increasing the output of a sensor that detects the rotation speed. In the case of a rolling bearing unit with an encoder incorporating the encoder 1 as described above, in order to reduce the dimension in the axial direction, the axial dimension of the large-diameter cylindrical portion 2 protruding from the end face of the inner ring (and the outer ring) is required. Need to be smaller. On the other hand, in order to increase the output of the sensor, it is necessary to increase the axial dimension of the large-diameter cylindrical section 2 and sufficiently secure the axial dimension of the detected portion 5 provided on the large-diameter cylindrical section 2. There is. Therefore, in order to achieve both a reduction in the axial dimension of the rolling bearing unit with the encoder and an improvement in the output of the sensor,
It is necessary to devise the shape of the encoder 1.

Considering first the structure of the encoder 1 shown in FIG. 5, the large-diameter cylindrical portion 2 of the components constituting the encoder 1 has a small-diameter cylindrical The parts 3 each need to have a certain axial dimension in order to secure a sufficient fitting strength to the inner ring (rotating wheel). The inner peripheral surface of the distal end portion (left end portion in FIG. 5) of the small-diameter cylindrical portion 3 has a conical concave tapered surface portion 1 inclined in a direction in which the diameter dimension increases toward the distal end side.
9 (chamfer). Such a tapered surface portion 19
Is necessary as a guide surface when the small diameter cylindrical portion 3 is press-fitted into the end of the inner ring. For this reason, it is necessary to secure a certain axial dimension in order to form the tapered surface portion 19 at the inner end of the small diameter cylindrical portion 3. However, among the components constituting the encoder 1, the circular ring portion 4, the inner and outer peripheral edges of the circular ring portion 4 and the small-diameter and large-diameter double-cylindrical portions 3,
The bent portions 7, 7 existing in a continuous portion with the edge of 2 are
This is a portion generated by forming the encoder 1 to have a crank-shaped cross section, and is not always necessary for ensuring the function of the encoder 1. Therefore, the encoder 1
If the shape in which the ring portion 4 and the bent portions 7 are omitted is adopted, the axial dimension L of the portion where these portions 4 and 7 are present is determined by the axial dimension of the rolling bearing unit with encoder. It can be used to reduce the size and improve the output of a sensor that detects the rotational speed. A rolling bearing unit with an encoder according to the present invention has been invented in view of the above situation.

[0007]

A rolling bearing unit with an encoder according to the present invention has a stationary track on a stationary peripheral surface,
A stationary wheel that does not rotate even during use, and has a rotating track on a rotating peripheral surface opposite to the stationary peripheral surface, and a rotating wheel that rotates during use, between the stationary track and the rotating track. A plurality of rolling elements provided rotatably, and an encoder supported on the rotating wheel concentrically with the rotating wheel.
The encoder is entirely made of a magnetic metal plate, and includes a first cylindrical portion, a detected portion provided on the first cylindrical portion, and a second cylinder which can be fitted and fixed to an end of the rotating wheel. Of the first cylindrical portion, a plurality of thinned portions are formed intermittently (generally at regular intervals) in the circumferential direction. By forming a solid portion between each of the circumferentially adjacent thinned portions, the magnetic characteristics of at least a part of the first cylindrical portion are alternately arranged in the circumferential direction (generally, the first cylindrical portion). (Equally spaced). In the state where the second cylindrical portion is fitted and fixed to the end of the rotating wheel, at least a part of the first cylindrical portion is projected in the axial direction from the end surface of the rotating wheel. In particular, in the rolling bearing unit with the encoder according to the present invention, the diameters of the first cylindrical portion and the second cylindrical portion are made substantially equal to each other, and the axial edges of the first and second cylindrical portions are separated from each other. The encoder is formed in a single cylindrical shape by directly connecting the encoders.

[0008]

In the case of the rolling bearing unit with the encoder of the present invention configured as described above, the encoder makes the diameters of the first cylindrical portion and the second cylindrical portion substantially equal to each other, so that the first and second cylindrical portions have the same diameter. By directly continuing the axial edges of
This encoder is formed in a single cylindrical shape. That is, in the case of the encoder of the present invention, the circular ring portion 4 and the bent portions 7, 7 which are provided in the encoder 1 having the conventional structure shown in FIG. 5 described above are omitted. For this reason, the axial dimension of the entire first encoder can be reduced and the axial dimension of the entire encoder can be reduced by the amount of omitting the ring portion 4 and the bent portions 7. For this reason, it is possible to achieve both an improvement in the output of the sensor for detecting the rotational speed and a reduction in the axial dimension of the rolling bearing unit with the encoder.

[0009]

1 and 2 show a first embodiment of the present invention. An outer raceway 9 which is a stationary raceway is provided on an inner peripheral surface (stationary peripheral surface) of an outer race 8 which is a stationary race which is fitted and fixed to a portion which does not rotate even when using a casing or the like in a state of being assembled to various mechanical devices. Is formed. or,
An inner ring 10 that is a rotating wheel that is externally fitted and fixed to a portion that rotates when used, such as a rotating shaft, in a state of being assembled to the above-described various mechanical devices.
An inner raceway 11, which is a rotation-side track, is formed on the outer peripheral surface (rotation-side peripheral surface). A plurality of balls 12, each of which is a rolling element, is provided between the inner raceway 11 and the outer raceway 9 so as to freely roll.

Each of the balls 12 is rotatably held by a crown-shaped holder 13 made of synthetic resin. The retainer 13 is formed by providing a plurality of pockets 15 on one side (the right side in FIG. 1) of an annular rim portion 14 in the axial direction. Each ball 12 above
Inside each of these pockets 15
Are inserted while being elastically pushed open, and are held in these pockets 15 in such a manner that they can roll freely. In the case of the example shown in the drawing, the rim portion 14 of the retainer 13 is positioned on the opposite side to the rotation speed detecting device described below to prevent interference with the rotation speed detecting device when mounted on the rolling bearing unit. are doing.

An encoder 16 constituting a rotational speed detecting device is supported and fixed to one end (right end in FIG. 1) of the inner race 10 on the outer peripheral surface thereof. The whole encoder 16 is formed in a single cylindrical shape from a magnetic metal plate such as a mild steel plate. In addition, in the portion near one end of the encoder 16 (the portion near the right end in FIG. 1), a number of slit-shaped through holes 5 each of which is a thinned portion and are long in the axial direction are arranged at equal intervals in the circumferential direction. Thus, a large number of pillar portions 6 each of which is a solid portion are formed between the circumferentially adjacent through holes 5. Thus, a detected portion 38 whose magnetic properties change alternately and at equal intervals in the circumferential direction is provided near the one end of the encoder 16. That is, in the case of the present example, the one end portion of the encoder 16 including the portion where the detected portion 38 is formed is defined as the first cylindrical portion 17, and the other end side of the portion where the detected portion 38 is formed ( A portion (on the left end side in FIG. 1) is a second cylindrical portion 18 which can be externally fitted and fixed to one end of the inner ring 10. The inner peripheral surface of the other end of the second cylindrical portion 18 is formed with a tapered surface 19 having a conical concave shape, which is inclined in such a direction that the diameter increases toward the other end. Such a tapered surface portion 1
9, the second cylindrical portion 18 is connected to the inner race 10 as described below.
It functions as a guide surface when press-fitting into one end of the. For this reason, the diameter of the opening edge of the tapered surface portion 19 is made larger than the diameter of the outer peripheral surface of one end of the inner ring 10.

The encoder 16 as described above is connected to the inner ring 10
When externally fixed to one end of the inner ring 10, the second cylindrical portion 18 is press-fitted into the outer peripheral surface of one end of the inner ring 10 while being guided by the tapered surface portion 19. Such a press-fitting operation is performed based on the pressing force of the press-fitting jig pressed against one end edge of the first cylindrical portion 17. During the press-fitting operation using such a press-fitting jig, the pressing force of the press-fitting jig causes the encoder 16
The dimensions of each part of the encoder 16 are regulated so as not to be deformed.

On the other hand, on the inner peripheral surface of one end (right end in FIG. 1) of the outer ring 8, a base end of the sensor carrier 20 (FIGS.
2 (left end). The sensor carrier 20 includes a cover 21 made of a magnetic metal plate such as a soft steel plate such as SPCC, and a holding member 22 made of a synthetic resin held inside the cover 21. Cover 21 of these
Is formed in the shape of a ring with a crank-shaped cross section.
A fitting cylindrical portion 24 is formed on the inner peripheral edge of a ring-shaped abutting plate portion 23 formed at an intermediate portion in the axial direction, and a holding portion 25 is formed on the outer peripheral edge. And the fitting tube portion 24 of these
The cover 21 is connected and fixed to the outer ring 8 with the abutting plate 23 abutting against the one end surface of the outer ring 8 while the inner peripheral surface of the outer ring 8 is tightly fitted to the inner peripheral surface of the outer ring 8. ing. Note that such a cover 21 has a role of protecting the encoder 16 in addition to a role of supporting the sensor 27 described below.

The holding portion 25 has an L-shaped cross section and is formed in an annular shape as a whole. A holding member 22 made of synthetic resin is held and fixed inside a part of the holding portion 25 in the circumferential direction. In the illustrated example, the abutting plate 2
3 is provided with a plurality of (three in the illustrated example) through holes 26, 26, and the holding member 2 is inserted into each of the through holes 26, 26.
A part of the synthetic resin constituting the second member 2 is made to enter to secure the bonding strength between the holding member 22 and the cover 21.
The sensor 27 is embedded and supported inside the holding member 22. The structure of the sensor 27 is not particularly limited as long as it changes the output in response to a change in magnetic flux.
In the illustrated example, an active type is used. That is, the sensor 27 is replaced with a package 28 comprising a magnetic detection element such as a Hall element and a magnetoresistive element and a waveform shaping circuit.
And a permanent magnet 29 which supplies a magnetic flux flowing to the magnetic detection element and is formed in a rectangular parallelepiped shape from a rare earth element. A notch opening at the tip side (the right end side in FIGS. 1 and 2) of the holding portion 25 is provided in a part of the holding portion 25 that constitutes the cover 21 in the circumferential direction and near the sensor 27. 30 are provided. A harness (not shown) for extracting a detection signal of the sensor 27 can be freely derived through the cutout 30.

In a state where the sensor carrier 20 supporting the above-described sensor 27 is supported and fixed to one end of the outer race 8, the detecting portion of the sensor 27
Is opposed via a minute gap extending in the radial direction. Further, in this state, the dimensions of the respective parts are regulated such that the leading edge of the holding part 25 constituting the cover 21 protrudes from the one end edge of the encoder 16 by δ in the axial direction. The reason for this is that when the rolling bearing unit with the encoder of this example is placed on a flat base or the like with the sensor carrier 20 and the encoder 16 facing downward, one end edge of the encoder 16 This is to prevent damage due to contact with the upper surface of the table or the like. If the value of δ is excessively increased, the axial dimension of the entire rolling bearing unit increases, or the axial dimension of the detection portion 38 of the encoder 16 decreases, and the output of the sensor 27 decreases. Therefore, the value of δ cannot be increased unnecessarily. Therefore, taking into account the processing accuracy of each member constituting the rolling bearing unit, the axial clearance of the rolling bearing unit, and the like, the inner ring 10 and the outer ring 8 constituting the rolling bearing unit are relatively displaced by the axial clearance. Also,
If the above-mentioned δ is constantly controlled to be within the range of 0 [mm] <δ <0.6 [mm], it is possible to prevent the encoder 16 from being damaged while suppressing an increase in cost due to maintenance of extreme dimensional accuracy. Is preferred.

When the above-described rolling bearing unit with encoder is used, the outer ring 8 is internally fitted to a fixed portion such as a casing, and the inner ring 10 is externally fitted to a rotating portion such as a rotating shaft. In the illustrated example, the base half of the spring pin 32 is inserted and held in a holding hole 31 provided in the other end surface (the left end surface in FIG. 1) of the outer ring 8. As described above, when the outer ring 8 is internally fitted and fixed to a fixed portion such as a casing, the first half of the spring pin 32 is engaged with another holding hole or notch formed in a part of the fixed portion. To prevent creep of the outer ring 8 as a stationary wheel,
Prevents the harness from breaking due to creep. As described above, when the rotating part such as the rotating shaft rotates in a state where the rolling bearing unit with the encoder of the present embodiment is assembled, the vicinity of the detecting portion of the sensor 27 is formed on the first cylindrical portion 17 of the encoder 16. The through-holes 5 and the pillars existing between the circumferentially adjacent through-holes 5 alternately pass through. As a result, the density of the magnetic flux flowing in the sensor 27 changes, and the output of the sensor 27 changes. The frequency at which the output of the sensor 27 changes in this way is proportional to the rotation speed of the rotating part. Therefore, if the output of the sensor 27 is sent to a controller (not shown) through the harness,
The rotation speed of the rotating part can be detected.

In the case of the present embodiment constructed and operated as described above, the encoder 16 is provided with a first cylindrical portion 17 provided with the detected portion 38 and a second cylindrical portion 17 fitted and fixed to the inner ring 10 serving as a rotating wheel. The diameters of the two cylindrical portions 18 are equal to each other, and the axial ends of the two cylindrical portions 17 and 18 are directly continuous with each other. That is, in the case of the encoder 16 of this example, the circular ring portion 4 and the bent portions 7, 7 which are provided in the encoder 1 of the conventional structure shown in FIG. 5 described above are omitted.
For this reason, the axial dimension of the encoder 16 as a whole is ensured while securing the axial dimension of the first cylindrical portion 17 on which the detected portion 38 is provided, by the amount of omitting the ring portion 4 and the bent portions 7. Can be reduced. Therefore, the sensor 2
7, and the reduction of the axial dimension of the rolling bearing unit with encoder can be achieved.

FIG. 3 shows a second embodiment of the present invention.
An example is shown. In the case of this example, the fitting cylindrical portion 24 of the cover 21 constituting the sensor carrier 20 is internally fitted and fixed to a large-diameter step portion 33 formed on the inner peripheral surface of one end of the outer ring 8. On the other hand, the first cylindrical portion 17 forming the encoder 16a has
An axially long notch 3 which is open to one end (right end in FIG. 3) of the first cylindrical portion 17, each of which is a thinned portion.
4 are formed at equal intervals in the circumferential direction, and between the notches 34 adjacent in the circumferential direction, a number of tongue pieces 35 each of which is a solid portion are formed. Thus, the first cylindrical portion 17 is provided with the detected portions 38a whose magnetic characteristics change alternately and at equal intervals in the circumferential direction. In the case of the present example, the notches 34 each opening at one end of the first cylindrical portion 17 are employed as a large number of thinned portions constituting the detected portion 38a. The same effect as increasing the axial length of each through hole 5, that is, the effect of increasing the axial dimension of the detected portion 38a and improving the output of the sensor 27 is obtained. In the case of the rolling bearing unit with the encoder incorporating the encoder 16a having the detected portion 38a, the rotation speed of the rotating portion such as the rotating shaft can be detected based on the same operation as in the first example described above.

Further, in the case of this embodiment, the rim portion which is continuous in the circumferential direction is eliminated from the leading edge of the encoder, and a number of notches 34 opening at one edge of the first cylindrical portion 17 are formed. Accordingly, the rigidity in the axial direction of the portion where each of the tongue pieces 35 is formed decreases, and the encoder 16a is connected to the inner race 1.
It can no longer withstand the load of press fitting to zero. Because of this,
An outward flange-shaped flange 36 for pressing the press-fitting jig is formed on the other end edge (left end edge in FIG. 3) of the second cylindrical portion 18 constituting the encoder 16a. Further, in the case of this example, with the formation of such a flange portion 36, the second cylindrical portion 18 is externally fitted and fixed to a small-diameter step portion 37 formed on the outer peripheral surface of one end of the inner ring 10, and The portion 36 is prevented from interfering with the rolling surfaces of the balls 12. Other configurations and operations are the same as those of the above-described first example.

FIG. 4 shows a third embodiment of the present invention.
An example is shown. In the case of the present example, an inward flange-like covering portion 39 is formed on an inner peripheral surface of one end (the right end in FIG. 4) of the holding member 22 made of a synthetic resin constituting the sensor carrier 20.
By making this cover portion 39 face one end edge of the encoder 16a, one end edge of the encoder 16a is protected. Also in the case of the present example, the distance δ between the leading edge of the encoder 16a and the cover portion 37 is regulated so as not to be too large, similarly to the dimension δ of the first example described above.
Other configurations and operations are the same as those of the above-described second example.

In each of the above-described examples, the case where the rotating wheel is an inner ring has been described. However, it goes without saying that the present invention can be applied to a rolling bearing unit with an encoder in which the rotating wheel is an outer ring. .

[0022]

Since the rolling bearing unit with encoder of the present invention is constructed and operates as described above, it is possible to achieve both improvement of the output of the sensor for detecting the rotational speed and miniaturization of the whole rolling bearing unit.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a cover constituting the sensor carrier.

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 partial sectional view showing an example of an encoder incorporated in a conventional structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Encoder 2 Large-diameter cylindrical part 3 Small-diameter cylindrical part 4 Circular ring part 5 Through-hole 6 Column part 7 Bent part 8 Outer ring 9 Outer ring raceway 10 Inner ring 11 Inner raceway 12 Ball 13 Cage 14 Rim part 15 Pocket 16, 16a Encoder 17 One cylindrical part 18 Second cylindrical part 19 Tapered surface part 20 Sensor carrier 21 Cover 22 Holding member 23 Butting plate part 24 Fitting cylindrical part 25 Holding part 26 Through hole 27 Sensor 28 Package 29 Permanent magnet 30 Notch 31 Holding hole 32 Spring Pin 33 Large diameter step 34 Notch 35 Tongue piece 36 Flange 37 Small diameter step 38, 38a Detected part 39 Cover part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01D 5/245 G01D 5/245 HR G01P 3/488 G01P 3/488 FCD

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 concentrically with the rotating wheel on the rotating wheel. The encoder is entirely made of a magnetic metal plate, and includes a first cylindrical portion, a detected portion provided in the first cylindrical portion, and a second cylindrical portion which can be fitted and fixed to an end of the rotating wheel. The to-be-detected portion has a plurality of thinned portions intermittently formed in at least a part of the first cylindrical portion in a 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 at least a part of the first cylindrical portion are circumferentially extended. In the state where the second cylindrical portion is fitted and fixed to the end of the rotating wheel, at least a part of the first cylindrical portion projects in the axial direction from the end surface of the rotating wheel. In the encoder-equipped rolling bearing unit, the diameters of the first cylindrical portion and the second cylindrical portion are substantially equal to each other, and the axial edges of the first and second cylindrical portions are directly continuous with each other. A rolling bearing unit with an encoder, wherein the encoder is formed in a single cylindrical shape.