JP2004354066A - Bearing device with built-in rotating speed sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device with a built-in rotating speed sensor excellent in sealing property. <P>SOLUTION: A cylindrical sensor mounting part 13 is provided on the lid part 5b of a synthetic resin-made cover 4 for closing an opening at one end of an outer ring 1, and a partitioning wall 16 for partitioning a sensor mounting hole 14 formed on the inner circumferential side thereof from a device internal space 15 is provided on the deep side of the mounting hole 14 integrally with the cover 5. According to this, since the sensor mounting hole 14 can be provided so as not to extend through the cover 5 without having an influence on the detection precision of rotating speed, the penetration route of foreign matters into the device can be reduced to improve the sealing property of the whole device. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device with a built-in rotation speed sensor, which has a built-in sensor for detecting a rotation speed of a wheel, among bearing devices that rotatably support wheels of an automobile.
[0002]
[Prior art]
Recently, the number of automobiles equipped with an ABS (anti-lock brake system) and a TCS (traction control system) has been increasing. In a vehicle equipped with these control systems, a device incorporating a sensor for detecting a rotation speed of a wheel required for control is usually used as a bearing device for a wheel.
[0003]
FIG. 3 shows an example of this type of bearing device with a built-in rotation speed sensor. As shown in FIG. 3 (a), this bearing device includes an outer ring 51, a shaft member 52 that rotates while being inserted into the inner peripheral side of the outer ring 51, and rolling between the outer ring 51 and the shaft member 52. A ball 53 freely disposed, an encoder 54 fixed to one end of a shaft member 52, a cover 55 attached to one end of the outer ring 51 to close an opening of one end of the outer ring 51, and an encoder 54 And a sensor 56 attached so as to face the portion. By fixing the outer race 51 and the shaft member 52 to a suspension device and wheels, respectively, which are not shown, the wheels are rotatably supported with respect to the suspension device, and the magnetic field fluctuation generated by the rotation of the encoder 54 is detected by the sensor 56. This is detected, converted into an electric signal proportional to the rotation speed, and output to an ABS or TCS control unit (not shown).
[0004]
As shown in FIG. 3B, the sensor 56 is attached to the cover 55 by inserting an insertion portion 56a of the sensor 56 into a sensor attachment hole 57 penetrating in the thickness direction of the cover 55. By incorporating an O-ring 59 into an annular groove 58 provided on the outer peripheral surface of the insertion portion 56a of the sensor 56, entry of foreign matter from the sensor mounting hole 57 into the device is prevented.
[0005]
As in this example, in a bearing device with a built-in rotational speed sensor used around the legs of an automobile, a rubber mounting material such as an O-ring is provided in a sensor mounting hole passing through the cover so that foreign matter such as muddy water does not enter the inside of the device. In many cases, a seal member is incorporated (for example, see Patent Document 1).
[0006]
[Patent Document 1]
JP-A-10-319027
[Problems to be solved by the invention]
However, in the conventional bearing device as described above, a rubber sealing member such as an O-ring cannot obtain sufficient sealing performance due to twisting or insufficient tightening allowance during assembly, and foreign matter such as muddy water enters the inside of the device. May invade. In addition, foreign substances may enter due to deterioration (hardening, cracking) during long-term use. When foreign matter enters the device, the foreign matter is caught between the rolling element and the outer ring or shaft member, shortening the life of the bearing. In addition, foreign matter adheres to the sensor or encoder, and the rotational speed is detected. There is a possibility that the accuracy may be reduced and the ABS or TCS may not operate normally.
[0008]
Therefore, an object of the present invention is to provide a bearing device with a built-in rotation speed sensor having excellent sealing properties.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides an outer ring fixed to a fixing member, a shaft member rotating while being inserted into an inner peripheral side of the outer ring, and a rollable member between the outer ring and the shaft member. A plurality of rolling elements, an encoder fixed to one end of the shaft member, a cover attached to one end of the outer ring to close an opening of one end of the outer ring, and a sensor mounting hole in the cover. A sensor mounted with a sensor that detects a magnetic field variation due to rotation of the encoder and outputs a signal proportional to the rotation speed, the sensor mounting hole of the cover; On the back side, a partition wall made of a non-magnetic material and separating the sensor mounting hole and the internal space of the apparatus is provided. Here, the back side of the sensor mounting hole refers to the inside of the device.
[0010]
That is, the sensor mounting hole of the cover and the internal space of the bearing device are separated by a non-magnetic partition wall, so that the sensor mounting hole does not penetrate the cover without affecting the detection accuracy of the rotational speed. This reduces the path of foreign matter entering the interior and improves the sealing performance of the entire device.
[0011]
By forming the partition wall integrally with the cover with a synthetic resin, the structure can be simplified and the labor for assembling can be reduced.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. This bearing device with a built-in rotational speed sensor is for a wheel of an automobile, and as shown in FIG. 1, an outer ring 1, a shaft member 2 that rotates while being inserted into the inner peripheral side of the outer ring 1, an outer ring 1 and a shaft member. 2, a plurality of balls 3 as rolling elements rotatably arranged, an encoder 4 fixed to one end of a shaft member 2, and one end of the outer ring 1 attached to one end of the outer ring 1. It basically includes a cover 5 that covers the opening, and a sensor 6 attached to the cover 5 so as to face a part of the encoder 4. The sensor 6 detects a magnetic field variation generated by rotation of the encoder 4, This is converted into an electric signal proportional to the rotation speed and output to an ABS or TCS control unit (not shown).
[0013]
The outer race 1 is configured such that a mounting portion 1a provided on an outer peripheral surface at one end side is fixed to a suspension device (not shown) by bolts. On the other hand, the shaft member 2 includes a hub 7 having a flange 7a on the outer peripheral surface on the other end side, and an inner ring 8 attached to the outer periphery on one end side of the hub 7, and the flange 7a of the hub 7 is illustrated by a stud 9. It is fixed to the omitted wheel. The outer ring 1 and the shaft member 2 are made of metal, and a plurality of balls 3 held by a retainer 10 are arranged in a row between the outer ring 1 and the hub 7 and between the outer ring 1 and the inner ring 8. ing. The gap between the inner peripheral surface on the other end side of the outer ring 1 and the outer peripheral surface of the hub 7 is closed by a seal ring 11.
[0014]
The encoder 4 includes a cylindrical mounting portion 4a fitted around the outer periphery of one end of the inner ring 8, and an encoder body 4b mounted on a flange at one end of the mounting portion 4a. The encoder body 4b is formed by annularly forming permanent magnets such as rubber magnets, sintered magnets, resin magnets, etc. in such a manner that the S pole and the N pole alternately appear in the circumferential direction. The rotation of the direction causes a magnetic field fluctuation. Note that a gear-type pulsaring may be used as the encoder body.
[0015]
The cover 5 is formed of a synthetic resin into a closed cylindrical shape, and its cylindrical portion 5a is press-fitted into the inner periphery of one end of the outer race 1 and mounted on the outer race 1, and an opening at one end of the outer race 1 is opened with the lid 5b. Is blocking. The cylindrical portion 5a is formed with a flange 12 which is in contact with one end surface of the outer ring 1 so that the entire cover 5 is accurately positioned in the axial direction with respect to the outer ring 1 and the position of the sensor 6 attached to the cover 5 is managed. Can be easily performed.
[0016]
As shown in FIG. 2, a cylindrical sensor mounting portion 13 is provided on the cover 5b of the cover 5, and the insertion portion 6a of the sensor 6 is inserted into a sensor mounting hole 14 formed on the inner peripheral side. It has become so. A partition wall 16 having a thickness of 0.3 to 0.5 mm (preferably 0.3 mm) is provided behind the sensor mounting hole 14 (inside the device) to partition the mounting hole 14 and the device internal space 15. ing. Since the partition wall 16 is formed integrally with the cover 5 and its synthetic resin is non-magnetic, it does not affect the rotational speed detection accuracy.
[0017]
The sensor 6 has an exterior part made of synthetic resin, and is attached to the cover 5 by inserting an insertion portion 6 a into the sensor attachment hole 14 of the cover 5. The insertion portion 6a is opposed to a part of the encoder body 4b with a predetermined interval across a partition wall 16 on the back side of the sensor mounting hole 14, and the insertion portion 6a is located near the surface facing the encoder body 4b. A detection unit (not shown) for detecting a magnetic field fluctuation generated by the rotation of No. 4 is built in. The detection unit is connected to one end of the output cable 17 in the sensor 6, converts the detected magnetic field fluctuation into an electric signal proportional to the rotation speed, and outputs the electric signal via the cable 17. It has become.
[0018]
This bearing device is configured as described above, and is provided with a partition wall 16 that separates the mounting hole 14 and the device internal space 15 on the back side of the sensor mounting hole 14 of the cover 5, so that the bearing device is compared with a conventional device. Since the sensor mounting hole does not penetrate the cover, there is little passage of foreign matter into the inside of the device, and the sealing performance of the entire device is excellent.
[0019]
Further, since the partition wall 16 is formed integrally with the cover, the structure is simple and the assembling work is reduced.
[0020]
In the above-described embodiment, the partition wall is formed integrally with the cover with a synthetic resin. However, the partition wall may be formed separately from the cover and attached so as to be in close contact with the cover. In this case, the material of the partition wall is not limited to the same synthetic resin as the cover, and may be any non-magnetic material that does not affect the detection accuracy of the rotational speed. Also, the thickness of the partition wall can be changed within a range that does not change the distance between the insertion portion of the sensor and the encoder main body.
[0021]
The present invention is not limited to the vehicle wheel described in the embodiment, but can be effectively applied to a bearing device with a built-in rotation speed sensor used in a place where there is a high possibility of foreign matter intrusion.
[0022]
【The invention's effect】
As described above, the present invention provides a partition wall that separates the sensor mounting hole of the cover of the bearing device with a built-in rotational speed sensor from the internal space of the device so that the sensor mounting hole does not penetrate the cover. Thus, the invasion path of foreign substances can be reduced, and the sealing performance of the entire apparatus can be improved.
[0023]
Therefore, it is possible to extend the life of the bearing device, prevent the detection accuracy of the rotational speed from decreasing over a long period of time, and stabilize a system that performs control using the detected rotational speed.
[0024]
Also, since the number of sealing members such as O-rings can be reduced, the assembly work of the apparatus is simplified, and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a front sectional view of a bearing device with a built-in rotational speed sensor according to an embodiment; FIG. 2 is an enlarged sectional view of a main part of the bearing device of FIG. 1; FIG. And b are enlarged cross-sectional views of main parts of a.
DESCRIPTION OF SYMBOLS 1 Outer ring 1a Attachment part 2 Shaft member 3 Ball 4 Encoder 4a Attachment part 4b Main body 5 Cover 5a Tube part 5b Cover part 6 Sensor 6a Insertion part 7 Hub 7a Flange 8 Inner ring 9 Stud 10 Cage 11 Seal ring 12 Flange 13 Sensor attachment part 14 Mounting hole 15 Internal space 16 Partition wall 17 Cable

Claims (2)

An outer ring fixed to a fixing member, a shaft member that rotates while being inserted into the inner peripheral side of the outer ring, a plurality of rolling elements rotatably arranged between the outer ring and the shaft member; An encoder fixed to one end of the member, a cover attached to one end of the outer ring and closing an opening of one end of the outer ring, attached to a sensor mounting hole of the cover so as to face a part of the encoder, A sensor that detects a magnetic field variation due to rotation of the encoder and outputs a signal proportional to the rotation speed. A bearing device with a built-in rotation speed sensor, wherein a partition wall is provided for partitioning a mounting hole from a space inside the device. The bearing device with a built-in rotation speed sensor according to claim 1, wherein the partition wall is formed integrally with the cover by a synthetic resin.

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