JP2008170171A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel, which is suitably used as the axle unit of a large-size vehicle, and can correctly detect the rotation of the wheel at any time, preventing any change in positional relation between a magnetic encoder and a magnetic sensor due to rust occurrence, even if a housing is made of an easily rusting material such as nodular graphite cast iron. <P>SOLUTION: The bearing device 1 for a wheel includes double row rolling bearings 2, and the housing 7 having the outer ring 4 of the rolling bearings 2 press-fitted to the inner peripheral surface of the housing 7, the housing 7 being made of cast iron and used for attaching a ring hub 34. The magnetic encoder 17 having an inside diameter fitting portion 18b and an outside diameter fitting portion 18c to be fitted to the inside diameter surface and the outside diameter surface of the housing 7 is disposed on the end in the axial direction of the housing 7. This prevents the end surface in the axial direction of the housing 7 from rusting. Accordingly, it is prevented that the positional relation between the magnetic encoder 17 and the magnetic sensor 21 opposed to the magnetic encoder 17 changes, which may occur due to the movement in the axial direction of the magnetic encoder 17 that is pushed by the rust. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wheel bearing device used as an axle unit for large vehicles such as trucks and buses.

As an axle unit for a large vehicle, for example, a structure disclosed in Patent Document 1 is known. As shown in FIG. 2, the axle unit includes a unitized double row rolling bearing 2 and an annular housing 7 in which the outer ring 4 of the rolling bearing 2 is fitted to the inner periphery. To which a hub 34 and a brake rotor 35 are attached. Wheels (not shown) are attached to the hub 34.
Japanese Patent Laid-Open No. 2003-312205

  Many recent automobiles are equipped with an anti-lock brake device (ABS) in order to obtain steering stability. In an automobile equipped with an anti-lock brake device, an ABS sensor that detects tire lock is provided in the axle unit. The ABS sensor includes a magnetic encoder attached to the rotation side member of the axle unit and a magnetic sensor attached to the fixed side member so as to face the magnetic encoder.

Although there is no specific explanation, Patent Document 1 also shows a diagram A that is considered to be a magnetic encoder of a rotation detection device such as an ABS sensor. Assuming that A is a magnetic encoder, as shown in FIG. 2B, the magnetic encoder A in this example has an L-shaped cross section composed of an end surface contact portion Aa and an outer diameter fitting portion Ab. The end surface abutting portion Aa is abutted against the end surface of the housing 7 and the outer diameter fitting portion Ab is fitted to the outer diameter surface of the housing 7 to be attached to the housing 7. Not limited to this, the magnetic encoder is generally provided in this way.
An annular multipolar magnet having a plurality of magnetic poles arranged in the circumferential direction is formed in a part of the magnetic encoder A, for example, the end surface abutting portion Aa, and the magnetic sensor 21 faces the multipolar magnet. Is provided. As the magnetic encoder A rotates, the magnetic sensor 21 detects the magnetic poles of the multipolar magnet that crosses the front of the magnetic sensor 21, thereby detecting the rotation of the wheel attached to the axle unit.

  By the way, in a large vehicle axle unit, the material of the housing 7 and the hub 34 is often spheroidal graphite cast iron (FCD). Spheroidal graphite cast iron has a larger amount of carbon than carbon steel such as S55C. Generally, it is said that steel materials are more likely to rust as the amount of carbon increases.

  For this reason, when the magnetic encoder A is provided as shown in FIG. 2 with respect to the housing 7 made of spheroidal graphite cast iron, rust is easily generated on the end surface of the housing 7 that is not covered by the magnetic encoder A. When the magnetic encoder A travels to the inside of the end surface abutting portion Aa, the magnetic encoder A may be pushed by rust and move in the axial direction, causing a malfunction of the rotation detecting device. That is, the positional relationship between the magnetic encoder A and the magnetic sensor 21 changes, and the rotation detection device cannot accurately detect the rotation of the wheel. When the antilock brake device is operated based on the detection result of the rotation detection device, there is a concern that the antilock brake device may not operate correctly.

  The object of the present invention is suitable for use as an axle unit for large vehicles, and even when the housing is made of a material that is relatively susceptible to rust such as spheroidal graphite cast iron, the positional relationship between the magnetic encoder and the magnetic sensor changes due to rust. It is an object of the present invention to provide a wheel bearing device that can always detect the rotation of the wheel accurately.

  A wheel bearing device according to the present invention is a wheel bearing device comprising a double row rolling bearing and a cast iron annular hub mounting housing in which an outer ring of the rolling bearing is press-fitted into the inner periphery, A magnetic encoder having an inner diameter fitting portion and an outer diameter fitting portion that are fitted to the inner diameter surface and the outer diameter surface of the housing is provided at an end portion in the axial direction of the housing.

  This wheel bearing device is used as an axle unit by attaching a hub and a brake rotor to a hub mounting housing. Since the inner diameter surface and outer diameter surface of the axial end portion of the housing are covered with the inner diameter fitting portion and outer diameter fitting portion of the core bar of the magnetic encoder, it is possible to prevent rust from proceeding to the end surface of the housing. It is. For this reason, it is possible to prevent the rotation detection device from causing a malfunction by moving the magnetic encoder in the axial direction due to rust generated on the end face of the housing and changing the positional relationship between the magnetic encoder and the magnetic sensor.

The magnetic encoder may be an axial magnetic encoder.
Even if the magnetic encoder is an axial type, the magnetic encoder due to rust can be prevented from moving in the axial direction, and the change in the air gap between the magnetic encoder and the magnetic sensor can be eliminated.

A magnetic encoder according to the present invention is a magnetic encoder provided in a wheel bearing device including a double row rolling bearing and a cast iron-made annular hub mounting housing in which an outer ring of the rolling bearing is press-fitted into an inner periphery. An end face abutting portion that abuts against the axial end surface of the housing, and an inner diameter fitting portion and an outer diameter that fit to the inner diameter surface and the outer diameter surface of the housing following the inner and outer peripheral edges of the end surface abutting portion. An annular multi-pole magnet having a plurality of magnetic poles arranged in the circumferential direction is formed on the end surface abutting portion of the core metal, having an annular core metal with a fitting portion and a U-shaped cross section. It is characterized by that.
With this configuration, the inner diameter surface and the outer diameter surface of the axial end of the housing are covered by the inner diameter fitting portion and the outer diameter fitting portion of the core bar of the magnetic encoder, so that rust progresses to the end surface of the housing. Is prevented. For this reason, it is possible to prevent the rotation detection device from causing a malfunction by moving the magnetic encoder in the axial direction due to rust generated on the end face of the housing and changing the positional relationship between the magnetic encoder and the magnetic sensor.

  The wheel bearing device of the present invention is a wheel bearing device comprising a double row rolling bearing, and a cast iron-made annular hub mounting housing in which an outer ring of the rolling bearing is press-fitted into the inner periphery. Suitable for use as an axle unit for large-sized vehicles because a magnetic encoder having an inner diameter fitting portion and an outer diameter fitting portion that fits the inner diameter surface and outer diameter surface of the housing is provided at the axial end of the housing. Even when the housing is made of a material that is relatively rusting, such as spheroidal graphite cast iron, the positional relationship between the magnetic encoder and the magnetic sensor does not change due to rust, and the rotation of the wheel can always be accurately detected. .

  A first embodiment of the present invention will be described with reference to FIG. This embodiment is an outer ring rotating type, and shows a state where it is used for an axle unit for a driven wheel of a large vehicle such as a truck or a bus. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side.

  The wheel bearing device 1 is composed of a double row rolling bearing 2 and a hub mounting housing 7 fitted to the outer periphery of the rolling bearing 2. The rolling bearing 2 includes two inner rings 3 each having a raceway surface 3a on the outer peripheral surface, an outer ring 4 having a double-row raceway surface 4a facing the raceway surface 3a of the inner ring 3, and the inner and outer rings. The rolling element 5 of the double row | line | column integrated between 3 and 4 is provided. In the case of this embodiment, the rolling elements 5 are tapered rollers, and double rows of tapered rollers are arranged in a back surface combination and are held by the cage 6 for each row. Both ends of the bearing space between the inner ring 3 and the outer ring 4 are sealed by seals 8 and 9, respectively.

  The housing 7 is an annular member, and an inner diameter surface 11 thereof is formed by a press-fitting surface portion 11a into which the outer ring 4 of the rolling bearing 2 is press-fitted, and a press-fitting surface portion 11a continuing to the press-fitting surface portion 11a to the outboard side through a step portion 11b. Is formed in a stepped cylindrical surface shape having a small diameter surface portion 11c. Bolt holes 12 for attaching the hub and the brake rotor are provided at a plurality of locations in the circumferential direction on the end face of the housing 7 on the outboard side.

  The rolling bearing 2 is assembled in the housing 7 by press-fitting the outer ring 4 into the inner surface press-fitting surface portion 11 a of the housing 7 from the inboard side. In the assembled state, the end surface on the outboard side of the outer ring 4 abuts on the inner surface step portion 11b of the housing 7, and the movement of the rolling bearing 2 toward the outboard side is restricted. In a state in which the rolling bearing 2 is incorporated in the housing 7, the housing 7 protrudes more toward the inboard side than the outer ring 4, and the inner ring surface of the protruding portion of the housing 7 prevents the outer ring 4 from coming off to the inboard side. A retaining ring 15 is attached.

  A magnetic encoder 17 is fixedly provided at the inboard side end of the housing 7. The magnetic encoder 17 is configured as a rotation detection device 22 in combination with a magnetic sensor 21 described later. The rotation detection device 22 is used as an ABS sensor for detecting tire lock, for example, and an antilock brake device is operated based on the detection result.

  The magnetic encoder 17 is of an axial type, and as shown in FIG. 1B, an end surface abutting portion 18a that abuts on the inboard side end surface of the housing 7, an inner peripheral edge of the end surface abutting portion 18a, and Continuing from the outer peripheral edge, an annular cored bar 18 having a U-shaped cross section composed of an inner diameter fitting portion 18b and an outer diameter fitting portion 18c fitted to the inner diameter surface and the outer diameter surface of the housing 7 is provided. An annular multipolar magnet 19 having a plurality of magnetic poles arranged in the circumferential direction is formed on the end surface contact portion 18 a of the gold 18. Here, the multipolar magnet 19 is a rubber magnet that is magnetized by vulcanizing and bonding rubber mixed with a magnetic material to the inboard side surface of the end face contact portion 18a. Instead of the rubber magnet, a plastic magnet or a sintered magnet may be provided.

  The magnetic sensor 21 is attached to the fixed side member of the axle unit so as to face the inboard side surface of the multipolar magnet 19. In this embodiment, the fixed side member is the base 31a of the fixed shaft 31 fixed to the knuckle. As the magnetic encoder 17 rotates, the magnetic sensor 21 detects the magnetic poles of the multipolar magnet 19 that crosses the front of the magnetic sensor 21, so that the rotation detector 22 detects the rotation of the wheel attached to the axle unit. .

  When the wheel bearing device 1 is assembled as, for example, an axle unit for a driven wheel of a truck, the fixed shaft 31 is inserted into the inner periphery of the inner ring 3, and a nut 32 is attached to a screw portion 31b on the distal end side of the fixed shaft 31. Then, the inner ring 3 is width-tightened by the nut 32 and the large-diameter portion 31 c on the base side of the fixed shaft 31. Further, the hub 34 and the brake rotor 35 are attached to the housing 7 by bolts 33 screwed into the bolt holes 12. A wheel (not shown) is attached to the hub 34 with hub bolts 36.

  Further, since the magnetic encoder 17 has the above shape, the inner diameter surface and the outer diameter surface of the end portion on the inboard side of the housing 7 are the inner diameter fitting portion 18b and the outer diameter fitting portion 18c of the core metal 18 of the magnetic encoder 17. The rust is prevented from proceeding to the inboard side end surface of the housing 7. For this reason, the magnetic encoder 17 moves in the axial direction due to the rust generated on the end surface on the inboard side of the housing 7 and the air gap between the magnetic encoder 17 and the magnetic sensor 21 changes, so that the rotation detection device 22 malfunctions. Can prevent it. Therefore, the rotation detection device 22 can always detect the rotation of the wheel with high accuracy. Also, the antilock brake device always operates correctly.

In this embodiment, the magnetic encoder 17 is an axial type, but the magnetic encoder 17 may be a radial type.
Further, in this embodiment, the rolling bearing 2 is a tapered roller bearing type, but may be a ball bearing type such as an angular ball bearing.
In this embodiment, the wheel bearing device 1 is used for a driven wheel axle unit. However, the wheel bearing device of the present invention can also be applied to a drive wheel axle unit.

(A) is sectional drawing of the axle unit incorporating the wheel bearing apparatus concerning embodiment of this invention, (B) is the IB section enlarged view. (A) is sectional drawing of the conventional axle unit, (B) is the IIB part enlarged view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wheel bearing apparatus 2 ... Rolling bearing 3 ... Inner ring 4 ... Outer ring 7 ... Housing 17 ... Magnetic encoder 18 ... Core metal 18a ... End surface contact part 18b ... Inner diameter fitting part 18c ... Outer diameter fitting part 19 ... Multipolar Magnet 21 ... Magnetic sensor 34 ... Hub 35 ... Brake rotor

Claims (3)

A wheel bearing device comprising a double-row rolling bearing and a cast iron-made annular hub mounting housing in which an outer ring of the rolling bearing is press-fitted into the inner periphery,
A wheel bearing device comprising a magnetic encoder having an inner diameter fitting portion and an outer diameter fitting portion that are fitted to an inner diameter surface and an outer diameter surface of the housing at an axial end portion of the housing.   2. The wheel bearing device according to claim 1, wherein the magnetic encoder is an axial magnetic encoder.   A magnetic encoder provided in a wheel bearing device comprising a double-row rolling bearing and a cast iron annular housing for housing in which an outer ring of the rolling bearing is press-fitted into the inner circumference, the axial direction of the housing A cross section comprising an end surface abutting portion that abuts on the end surface, and an inner diameter fitting portion and an outer diameter fitting portion that are fitted to the inner diameter surface and the outer diameter surface of the housing following the inner and outer peripheral edges of the end surface contact portion. A magnetic encoder having a U-shaped and annular cored bar, and an annular multipolar magnet having a plurality of magnetic poles arranged in the circumferential direction formed on the end surface contact portion of the cored bar. .

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