JP2003074570A - Bearing device for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight and inexpensive bearing device capable of firmly fitting and retaining the inner wheel made of a high strength and thin-walled pressed item in the raceway of a cast bearing, regarding a bearing device for wheels equipped with rolling bearing at the outer periphery of the axis body such as the hub unit for vehicle. SOLUTION: The bearing device is provided with a casting axis body 2, a pair of inner rings 31, 32 installed side by side in the axial direction at the outer peripheral face of the axis body 2, the outer ring 33 rotatably arranged coaxially at the outer periphery of the inner rings 31, 32, and plural rows of rolling bodies 36, 37 respectively interposed between the inner rings 31, 32 and the outer ring 33. One inner ring 31 is formed of a thin-walled press forming item, and retains the opposite axial end against the other inner ring 32 by means of the axis body 2, and is fixed in the axis body 2 by casting or press fitting. The axial end face of the other inner ring 32 is fastened in one inner ring 31 direction by a nut 40 to impart a preload onto the rolling bodies 36, 37 and fix the inner rings 31, 32 to the axis body 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device for an axle, such as a hub unit for a vehicle, in which a rolling bearing is mounted on the outer periphery of a shaft body.

[0002]

2. Description of the Related Art Generally, a hub unit for a vehicle has a structure in which a double row rolling bearing is attached to the outer periphery of a shaft body of a hub wheel in a state of being prevented from coming off.

Rolling bearings include an inner ring mounted on the outer periphery of a shaft, an outer ring fixed to a vehicle body through a steering knuckle, a double row rolling element arranged between the inner ring and the outer ring, a retainer holding the rolling element, and an end. It is composed of a sealing member having a closed portion.

[0004]

Conventionally, the shaft body and the inner and outer rings of the rolling bearing are formed by forging using a material having a high strength capable of withstanding the load of the bearing.

However, there is a problem in that the cost is increased by using a high strength material. Further, in the case of forging, there is a problem that it takes a lot of time to process and the yield is low, so that the manufacturing cost becomes high.

Therefore, there is a demand for cost reduction by using a low-strength, inexpensive material and forming the shaft body and the inner and outer rings by, for example, casting instead of forging.

[0007] However, simply casting using a low-strength, inexpensive material cannot withstand the load of the bearing. Therefore, a thin press-molded article made of a high-strength material is mounted only on the raceway portion, A bearing device that can withstand a load has been proposed.

However, in the case of a thin press-molded product, for example, when it is mounted on the outer peripheral surface of the shaft body, it is not possible to secure a sufficient interference allowance, so that the holding strength becomes low and the shaft is displaced in the axial direction during the rotational operation. There was a problem. Further, there has been a problem that a sufficient preload cannot be applied to the rolling elements and the fixing strength between the inner ring and the shaft is weakened.

According to the present invention, an inner ring made of a high-strength, thin-wall press-molded product can be firmly held and mounted on a raceway portion of a cast bearing, and a sufficient preload is applied to the rolling elements to provide the inner ring and the shaft body. It is an object of the present invention to provide a lightweight and inexpensive bearing device for an axle that can firmly fix the bearing.

[0010]

A bearing device for an axle according to the present invention comprises a cast shaft body, a pair of inner rings mounted axially on the outer peripheral surface of the shaft body, and concentric with the outer periphery of the inner ring. An outer ring rotatably disposed on the inner ring, and a double row rolling element interposed between each inner ring and the outer ring, wherein the one inner ring is formed of a thin press-molded product, The axial end portion on the opposite side to the other inner ring is held by the shaft body and fixed to the shaft body by casting or press fitting, and the axial end surface of the other inner ring is fastened by the fastening means. By fastening in the inner ring direction, a preload is applied to the rolling element to fix the inner ring to the shaft body.

The fastening means is a nut screwed on the shaft body or caulking formed on the shaft body.

According to the bearing device for an axle of the present invention, one inner ring of a pair of inner rings mounted axially side by side on the outer peripheral surface of a cast shaft body is formed of a thin press-molded product, and the other one is formed. The inner ring of is held by the shaft at the axial end on the opposite side to the other inner ring, and the other inner ring fastened in the direction of one inner ring by the fastening means is strong enough with a margin. In addition, the inner ring and the shaft body can be firmly fixed by being applied to the rolling element by applying sufficient preload to the rolling element. In this way, since the inner ring is made of a high-strength press-molded product and the shaft body is made of cast metal,
It is possible to obtain a bearing device that is lightweight and inexpensive and can withstand the load of the bearing sufficiently.

Further, in the bearing device for an axle of the present invention, an outer ring raceway member made of a thin press-molded product having a raceway ring formed on the inner surface is mounted on the inner peripheral surface of the outer race, and the axial end surface of the outer ring raceway member is mounted. May be held by a holding means.

As described above, since the outer ring raceway member is formed of a thin press-molded product and held by the holding means, a lighter and cheaper bearing device can be obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) Embodiment 1 of the present invention will be described with reference to FIG.

FIG. 1 is a sectional view of an axle bearing device including a hub unit on the driven wheel side for a vehicle according to the first embodiment.

In FIG. 1, reference numeral 1 denotes a hub wheel to which wheels are attached, and a double row rolling bearing 3 is externally fitted to the outer peripheral surface of a shaft body 2 to which the wheels of the hub wheel 1 are attached by press fitting from the vehicle inner side. It is installed.

The double-row rolling bearing 3 is composed of an angular ball bearing, and has a pair of inner rings 31 and 32, an outer ring 33 fixed to the vehicle body through a steering knuckle, and a pair of outer ring race members 34 provided on the inner peripheral surface of the outer ring 33. , 35, inner rings 31, 32
36 and 37, which are double rows of rolling elements arranged along the track and outer ring track members 34 and 35, and balls 36 and 3 in each row.
It is composed of a retainer 38 that holds 7 and a seal member 39 that closes the outer side end of the vehicle.

After the rolling bearing 3 is press-fitted into the outer peripheral surface of the shaft body 2 from the vehicle inner side, a nut 40 serving as a fastening means is screwed into the shaft body 2 and fastened to the axial end surface of the inner ring 32 on the vehicle inner side. To do. Further, the cover 41 is covered from the vehicle inner side. A bent portion 42 is formed on the outer peripheral surface of the cover 41, and the bent portion 42 is pressed against the vehicle inner end of the outer ring 33 to hold the outer ring 33 in the axial direction. In this way
A sufficient preload is applied to the balls 36 and 37 to fix the rolling bearing 3 to the shaft body 2.

Next, the structure of each part of the bearing device will be described in detail.

The shaft 2 and the outer ring 33 are castings formed by injecting ordinary cast iron, malleable cast iron, light metal such as aluminum, synthetic resin such as FRP, etc. into a mold. Inside the shaft body 2, a hollow portion 43 is formed from the vehicle outer side over substantially the entire axial length of the bearing.

The inner ring 31 and the outer ring race members 34, 35 on the outer side of the vehicle are made of carbon steel, bearing steel, alloy steel such as manganese steel, or the like by press molding so as to withstand the load of the bearing. Become.

Further, the inner ring 32 on the vehicle inner side is formed by forging using carbon steel, bearing steel, alloy steel or the like.

The inner ring 31 is fixed to the shaft body 2 by casting or press fitting. The end portion of the inner ring 31 on the vehicle outer side is fitted in a notch portion 2a formed in the shaft body 2 and is held in the axial direction.

In the casting, the inner ring 31 is placed in the mold, the material is poured into the mold, and the shaft 2 is cast. In addition, in order to prevent the shaft body 2 and the inner ring 31 from being displaced from each other in the axial direction and the circumferential direction, the surface of the inner ring 31 may be roughened to prevent the interface between the shaft body 2 and the inner ring 31 from slipping. . In order to prevent the inner ring 31 from idling in the circumferential direction with respect to the shaft body 2, for example, the inner ring 31 may be spline-fitted to the shaft body 2.

Press-fitting is to press-fit and fix the inner ring 31 from the vehicle inner side to the outer peripheral surface of the shaft body 2. In this case as well, the surfaces of the inner ring 31 and the shaft body 2 may be roughened to prevent the interfaces from slipping or may be spline-fitted to each other.

In this way, the inner ring 31 is fixed to the shaft body 2, and the rolling bearing 3 is obtained by removing the inner ring 31 from the vehicle inner side.
Press fit. The rolling bearing 3 is assembled in advance with the inner ring 31 removed.

The outer ring raceway members 34 and 35 are cast into the outer ring 33 or press-fitted into the inner surface of the outer ring 33 from both axial sides, and fixed by abutting their end faces. In addition,
The casting and press fitting are the same as the casting and press fitting of the inner ring 31 and the shaft body 2 described above. Also in this case, the outer ring raceway member 3
The surfaces of 4, 35 and the outer ring 33 may be roughened to prevent slippage at the interfaces or to be spline-fitted to each other. Also,
When press-fitting, the outer ring raceway member 34 divided in the axial direction,
35 can be easily press-fitted into the inner surface of the outer ring 33 from both sides.

Further, the axial lengths of the outer ring raceway members 34, 35 are formed to be shorter than the axial length of the outer ring 33,
An insertion space for the seal member 39 is formed on the end surface of the outer ring raceway member 34 on the vehicle outer side. The seal member 39 is
The cored bar 39a is brought into contact with the axial end surface of the outer ring raceway member 34, positioned and mounted.

The core metal 39a of the seal member 39 serves as a holding means for axially holding the outer ring raceway member 34 on the vehicle outer side.

After the rolling bearing 3 is press-fitted, the nut 40 is fastened to the shaft body 2, the cover 41 is covered, and the rolling bearing 3 is fixed to the shaft body 2.

According to the bearing device for an axle thus constructed, the inner ring 31 on the vehicle outer side of the pair of inner rings 31, 32 mounted on the outer peripheral surface of the cast shaft body 2 side by side in the axial direction.
Is formed by a thin press-molded product, and the inner ring 31 has an axial end portion on the vehicle outer side, which is the opposite side to the inner ring 32 on the vehicle inner side, held by the shaft body 2 and is also supported by the nut 40. The inner ring 32 that is fastened in the direction of the inner ring 31 is firmly held with a sufficient interference margin, and sufficient preload is applied to the balls 36 and 37 to firmly fix the inner ring 31 and the shaft body 2. In this way, since the inner rings 31, 32 are made of high-strength press-molded products and the shaft body 2 is made of a lightweight and inexpensive casting, the inner rings 31, 32 can sufficiently bear the load of the bearing,
Moreover, a lightweight and inexpensive bearing device can be obtained.

Since the outer ring 33 is made of cast metal and the outer ring race members 34, 35 are made of thin press-molded products, a lighter and cheaper bearing device can be obtained. Moreover, since the outer ring 33 is made of cast metal, it is easy to process and the degree of freedom in designing the outer ring 33 is improved.

Further, since the shaft body 2 is a casting, it is easy to process, and the hollow portion 43 can be easily formed inside the shaft body 2 from the vehicle outer side to substantially the entire axial length of the bearing. . That is, there is a limit to the formation of a deep hollow portion in order to form the hollow portion inside the conventional forged shaft body. However, in the case of casting, it is possible to easily form the deep hollow portion 43 by changing the shape of the mold. In this way, by increasing the depth of the hollow portion 43, the wall-removing volume of the shaft body 2 increases, and the weight of the bearing can be reduced.

Further, the seal member 39 can be positioned and inserted into the insertion space of the end surface of the outer ring raceway member 34 by bringing the core metal 39a into contact with the outer ring raceway member 34, and the seal member 39 can be mounted accurately and easily.

Further, both sides of the outer ring raceway member 34 in the axial direction are held by the outer ring 33 and the core metal 39a of the seal member 39, respectively, so that the outer ring raceway member 34 can be firmly held.

The outer ring raceway members 34, 35 may be integrally molded and cast into the outer ring 33.

Further, the fastening means is not limited to the nut 40, but may be one in which the end portion of the shaft body 2 on the vehicle inner side is caulked radially outward so as to be fastened to the end surface of the inner ring 32.

(Second Embodiment) The second embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

The second embodiment is characterized in that the inner peripheral surface of the outer ring 33 is formed with a caulking 44 serving as a holding means which is fastened to the axial end surface of the outer ring raceway member 35 on the vehicle inner side. is there.

That is, the outer ring raceway members 34 and 35 are fixed to the inner peripheral surface of the outer ring 33 by casting or press fitting, and the inner surface of the outer ring 33 is caulked from the vehicle inner side by a caulking machine.
The caulking 44 is formed.

According to the bearing device for an axle constructed as described above, in addition to the effect described in the first embodiment, both axial sides of the outer ring raceway member 35 are held by the outer ring 33 and the caulking 44 respectively, and the outer ring raceway is held. The effect that the member 35 can be firmly held is obtained.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In the third embodiment, the extension portion 45, which extends the tip of the cover 41 toward the outer side of the vehicle and serves as the holding means, is provided.
Is abutted against the axial end surface of the outer ring raceway member 35 on the vehicle inner side.

According to the bearing device for an axle configured as described above, in addition to the effect described in the first embodiment, the outer ring 33 and the extending portion 45 of the cover 41 are provided on both axial sides of the outer ring race member 35, respectively. The effect that the outer ring raceway member 35 is held firmly can be obtained.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In the fourth embodiment, the outer ring 33 is a pair of press-molded products 3 formed by press-molding low carbon steel or the like into a thin wall.
3a, 33b, both press-molded products 33a, 33b
The flange is formed by spot welding. It should be noted that the outer peripheral portion of the outer ring 33 has a thinned portion 33 on the outer periphery thereof for the purpose of weight reduction.
c is formed.

The outer ring raceway members 34 and 35 are formed by press-molding high carbon steel or the like into a thin wall. Each outer ring race member 3
4, 35 are press-fitted and fixed to the inner surface of the outer ring 33, respectively.

With the bearing device for an axle configured as described above, the same effects as those described in the first embodiment can be obtained.

The present invention is not limited to the above-described embodiment, and various applications and modifications can be considered.

(1) The present invention is not limited to the axle bearing device including the hub unit on the driven wheel side, as shown in the above embodiment, but the axle bearing device including the hub unit on the driving wheel side. May be applied to.

(2) The present invention is not limited to the double row outward angular contact ball bearing as the bearing, as shown in the above-mentioned embodiment, but may be a rolling bearing having various oblique contact formations such as tapered rollers. I do not care.

(3) The present invention is not limited to the hub unit composed of the combination of the hub wheel and the rolling bearing with the oblique contact as shown in the above-mentioned embodiment, but the hub wheel or the like is used as the shaft body. A bearing device for an axle may be provided in which a rolling bearing such as an angular contact ball bearing with oblique contact is provided on the outer circumference of the shaft body.

[0054]

EFFECTS OF THE INVENTION According to the bearing device for an axle of the present invention, an inner ring made of a high-strength, thin-wall press-molded product can be firmly held and mounted on a raceway portion of a bearing made of cast metal, and can be sufficiently mounted on a rolling element. There is an effect that a preload can be applied to firmly fix the inner ring and the shaft body, and a lightweight and inexpensive bearing device can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of an axle bearing device including a driven wheel hub unit according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an axle bearing device including a driven wheel hub unit according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an axle bearing device including a driven wheel hub unit according to a third embodiment of the present invention.

FIG. 4 is a sectional view of an axle bearing device including a driven wheel hub unit according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 hub wheel Biaxial body 2a Notch 3 Rolling bearing 31,32 inner ring 33 outer ring 34,35 Outer ring race member 36,37 balls (rolling elements) 39a Core bar (holding means) 40 nuts (fastening means) 44 Caulking (holding means) 45 Extended portion (holding means)

Continued front page    F term (reference) 3J012 AB04 AB20 BB03 CB01 EB20                       FB10 GB10 HB01                 3J017 AA02 AA10 BA10 CA04 CA06                       DB02 DB07 DB09 HA02                 3J101 AA02 AA32 AA43 AA54 AA62                       BA53 BA56 BA63 DA09 FA44                       GA03

Claims (3)

[Claims] 1. A cast shaft body, a pair of inner rings axially mounted on the outer peripheral surface of the shaft body, an outer ring concentrically rotatably arranged on the outer periphery of the inner ring, and each inner ring. A plurality of rows of rolling elements respectively interposed between the outer rings, wherein the one inner ring is formed of a thin press-molded product, and has an axial end portion on the opposite side to the other inner ring. It is held by the shaft body and fixed to the shaft body by casting or press-fitting, and the axial end surface of the other inner ring is fastened in the one inner ring direction by a fastening means to preload the rolling element. A bearing device for an axle, characterized in that the inner ring is fixed to the shaft body. 2. The axle bearing device according to claim 1, wherein the fastening means is a nut screwed to the shaft body or a crimp formed on the shaft body. 3. An outer ring raceway member made of a thin press-molded product having a raceway ring formed on the inner surface is mounted on the inner peripheral surface of the outer race, and the axial end surface of the outer ring raceway member is held by a holding means. A bearing device for an axle according to claim 1.