JP2002323049A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing which can keep an initial bearing preload to develop assembling workability and keep the engagement of gears in a deceleration gear such as a drive pinion, a ring gear and the like. SOLUTION: The rolling bearing 1 is composed of an outer ring 2, an inner ring 3, a plurality of rolling elements 4, a holder 5 and a washer 6 of an L figure in cross section with the end of the inner ring 3 being press-fitted in, while a conical transfer face 2a is formed on the inner periphery of the outer ring 2, a conical transfer face 3a confronting to this transfer face 2a and a large color 3b and a large color 3b in the large diameter side of the transfer face 3a are formed in the inner ring 3. The plurality of rolling elements 4 and the holder 5 which rollably holds the rolling elements 4 equally in the circumferential direction are equipped in an annular space between the transfer face 2a of the outer ring 2 and the transfer face 3a of the inner ring 3. Surface treatment with abrasion resistance is performed on the surface of the washer 6 to restrict the wear of a treating material, inner ring 3, washer 6, and protect the occurance of stick-slip noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rolling bearing, and more particularly to a rolling bearing for rotatably supporting a gear shaft in a gear reduction device for a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a rolling bearing for rotatably supporting a gear shaft of a gear reduction device such as a differential or a transmission in an automobile or a construction machine, a radial load, an axial load, and a combined load thereof are applied. Tapered roller bearings that can be used are often used.

FIG. 4 shows a differential of a conventional automobile. A housing 50 has a pair of tapered roller bearings 51,
Drive pinion 5 rotatably supported via 52
3, a ring gear 54 meshing with the drive pinion 53, and a differential gear case 5 to which the ring gear 54 is attached and rotatably supported with respect to the housing 50.
5, a pinion (not shown) disposed in the differential gear case 55, and a pair of side gears (not shown) meshing with the pinion, and gear oil is sealed therein. It is housed in a housing 50. This gear oil also lubricates the tapered roller bearings 51, 52 and the like.

Normally, the tapered roller bearings 51 and 52 supporting the drive pinion 53 are given a preload in order to maintain good engagement between the drive pinion 53 and the ring gear 54. After mounting the pair of tapered roller bearings 51 and 52 via the seat 56, the nut 58 is tightened via a pinion flange 57 connected to a drive shaft (not shown), and the starting torque of the pair of tapered roller bearings 51 and 52 is increased. Or, the preload is controlled by the rotational torque.

A pair of tapered roller bearings having a large load capacity is generally used in construction machines and automobiles having a relatively heavy vehicle weight. In addition to this, a pair of angular ball bearings or a pair of angular ball bearings and a tapered roller bearing are used. It may be used in combination with a roller bearing.

[0006]

In the above-mentioned differential, when a high input torque load is applied, the drive pinion 53 is twisted, and between the end face of the tapered roller bearing 52 and the shoulder 53a of the drive pinion 53, as well as the tapered roller bearing. Sliding (stick-slip) may occur between the end face 51a of the pin 51 and the pinion flange 57. At this time, a metal sound such as a cockle, so-called stick-slip noise may be generated, and as a means for preventing this,
Between the end face of the tapered roller bearing 52 and the shoulder 53a of the drive pinion 53, or the end face 51 of the tapered roller bearing 51
Although a washer 59 is inserted between a and the pinion flange 57, not only does the assemblability deteriorate, but also
There was a problem that the washer 59 was worn to reduce the bearing preload, and the meshing between the drive pinion 53 and the ring gear 54 could not be maintained well.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has been developed in order to improve assemblability and maintain good meshing of gears in a gear reduction device such as a drive pinion and a ring gear. An object of the present invention is to provide a rolling bearing capable of maintaining the preload of the bearing.

[0008]

In order to achieve the above object,
An invention according to claim 1 of the present invention provides a rolling bearing comprising an inner ring, an outer ring, and a plurality of rolling elements housed in an annular space thereof, wherein a washer made of a steel plate having wear resistance at an end of the inner ring. Was fitted. With such a configuration, it is possible to prevent the occurrence of stick-slip noise, to improve the assemblability, and to reduce the wear of the washer as compared with a conventional configuration in which a separate washer is interposed.

According to a second aspect of the present invention, the washer has an L-shaped cross section, and has a cylindrical portion press-fitted to the outer diameter of the inner ring and a disk portion joined to the end face of the inner ring. Therefore, no special processing is performed on the inner ring or the washer itself for mounting the washer, and a low-cost rolling bearing with a simple configuration can be provided.

According to a third aspect of the present invention, by forming a nitrided layer on the surface of the washer by soft nitriding, the wear resistance of the washer is ensured and deformation by the surface treatment is minimized. Can be suppressed.

Further, as in the invention according to claim 4, by further setting the surface hardness of the washer to 400 Hv or more and the depth of the nitride layer to 20 μm or more,
Wear of the washer can be suppressed for a long period of time.

Further, when a surface layer made of a solid lubricant is formed on the surface of the washer as in the invention described in claim 5, generation of stick-slip noise generated between the rolling bearing and the mating member is further prevented. In addition, the wear of not only the washer but also a rolling bearing or a mating member that comes into contact with the washer can be suppressed.

In the invention according to claim 6, the invention is applied to a rolling bearing for rotatably supporting a gear shaft in a vehicle gear reduction device, so that a gear is generated between the rolling bearing and a mating member such as a gear. The occurrence of stick-slip noise can be prevented, and the wear of not only the washer but also a rolling bearing that contacts the washer or a mating member can be suppressed. Therefore, the initial preload of the rolling bearing can be maintained, and good gear engagement can be maintained for a long period of time.

According to a seventh aspect of the present invention, the rolling bearing comprises an outer ring having a conical rolling surface on an inner periphery;
A conical rolling surface facing the rolling surface, an inner ring having a large flange on the outer periphery of the rolling surface on the large diameter side, and an annular space between the rolling surface of the outer ring and the rolling surface of the inner ring. If the tapered roller bearing is provided with a plurality of tapered rollers rotatably accommodated in the tapered roller and a retainer for holding the tapered roller, the load capacity of the bearing is increased, such as trucks and other heavy vehicles. In construction machinery, it is possible to prevent the occurrence of stick-slip noise for a long period of time, and it is also possible to suppress the wear of not only the washer, but also the rolling bearing that comes into contact with the washer, or the mating member, thereby enabling maintenance-free operation. .

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a longitudinal sectional view of a rolling bearing according to the present invention.

In FIG. 1, a rolling bearing 1 includes an outer ring 2,
It comprises an inner ring 3, a plurality of rolling elements 4, a retainer 5, and a washer 6 having an L-shaped cross section which is press-fitted to an end of the inner ring 3. A conical rolling surface 2a is formed on the inner circumference of the outer ring 2, while a conical rolling surface 3a facing the rolling surface 2a and a large diameter of the rolling surface 3a are formed on the inner ring 3. Otsuba 3 on the side
b is formed on the outer periphery thereof. Rolling surface 2a of outer ring 2
A plurality of rolling elements 4 are provided in an annular space between the rolling element 3 and the rolling surface 3 a of the inner ring 3, and a retainer 5 for holding the rolling elements 4 so as to be able to roll freely and in a circumferential direction. .

The rolling surfaces 2a, 3a of the outer ring 2 and the inner ring 3
And the outer diameter of the rolling element 4 is formed with a crowning to suppress an increase in the contact surface pressure due to the edge load. In particular, both ends of the rolling surface 3a of the inner race 3 have a rolling surface width of 20 mm. %, A maintenance cycle can be significantly extended by forming a crowning having a drop amount of about 20 μm. This crowning may be a crowning composed of a single arc or a so-called cut crowning in which both ends are cut at a predetermined angle. Here, a tapered roller bearing using a tapered roller for the rolling element 4 has been illustrated, but a ball bearing such as an angular ball bearing using steel balls for the rolling element with an arcuate rolling surface formed on the inner and outer rings may be used.

The washer 6 press-fitted into the large collar 3b of the inner ring 3 is made of cold-rolled steel such as SPCC or S10C to S60C.
L-shaped section formed of a cylindrical portion 6a press-fitted to the outer diameter of the large flange 3b by press working and a disk portion 6b joined to the end surface 3c of the inner ring 3 by press working. (FIG. 2). As a means for integrating the washer 6 with the inner ring 3, for example, an annular groove may be formed in the outer diameter of the large flange 3 b of the inner ring 3, and after fitting the washer 6, the cylindrical portion 6 a may be swaged. The process and the caulking process require man-hours, and the cost of the rolling bearing 1 cannot be denied.

The washer 6 is generally subjected to a carburizing treatment or a nitriding treatment as a means for improving the wear resistance. However, since the plate thickness is as thin as about 0.5 mm, it is subjected to a gas nitrocarburizing treatment. I have. Usually, the nitrocarburizing treatment is performed at 540 to 5
The substrate is kept in an atmosphere such as 70 ° C. ammonia gas for 1 to 3 hours. In such a treatment, a nitride layer of about 400 Hv can be obtained on the surface, but the nitride layer depth (white layer depth) is at most 10 to 10. Only about 20μm can be obtained.
Under conditions where the wear amount exceeds m, the nitrided layer depth cannot be said to be sufficient. Conversely, if the wear exceeds this nitrided layer, the wear may be accelerated rapidly.

The present applicant can stably secure a surface hardness of 400 Hv or more and a nitride layer depth of at least 20 μm so that wear resistance can be maintained for a long time even under such severe conditions. A soft nitriding treatment was found. That is, the processing time was extended to about 4 hours, which is about twice the conventional value, and the processing temperature was changed over time in the range of 550 to 580 ° C. Also, regarding the arrangement of washers in the processing furnace, limit the number of washers to be introduced and determine the optimum conditions so that the corners of the processing furnace where ammonia gas and the like are difficult to spread can be avoided and the atmospheric gas can be uniform under the same conditions. Was.

Further, the surface of the washer 6, in particular, the disk 6
The surface of b is coated with an inorganic resin containing a solid lubricant such as molybdenum disulfide or graphite (trade name: defric coat, moly coat, sol vest treatment) to improve wear resistance and generate stick-slip noise. Can also be suppressed. This coating is inner ring 3
It may be formed on one or both of the inner surface contacting the end surface 3c and the outer surface contacting the mating member. The coating is not limited to this, and may be a lubricating coating containing a low molecular weight lubricating component in an organic resin containing tetrafluoroethylene or a matrix resin.

When such a rolling bearing is used for supporting a drive pinion of a differential, etc., since it has many meshing portions of gears and sliding portions of rotating members, metal abrasion powder or the like generated at these portions is required. Foreign matter enters the gear oil enclosed in the housing. These abrasion powders penetrate into rolling bearings, especially tapered roller bearings, which support gears rotating under high load, and promote the wear of rolling bearings, not only affecting gear meshing due to preload loss, but also bearings. May be problematic in terms of durability life.

Therefore, the inner ring of such a rolling bearing,
The outer ring and rolling elements are made of case hardened steel SCr435,
It is effective to form a carbonitrided layer having a carbon content of 0.80% by weight or more and 58HRc or more on each surface. Furthermore, by setting the amount of retained austenite of the carbonitrided layer in the range of 25 to 35% by volume, it is possible to secure the surface hardness of the carburized layer and suppress the generation and propagation of cracks. Furthermore, since a larger compressive residual stress is formed than in a normal carburized layer, the fatigue strength of the bearing can be increased.

The structure of the carbonitrided layer described above can be formed by the following processing steps. That is, after the carbon potential in the atmosphere is kept at 0.8% or more and heated and held for a predetermined time, it is cooled in oil to perform carburizing and quenching, and then is heated and held in an ammonia gas for a predetermined time to perform a nitriding treatment. . Further, a method of performing a nitriding treatment simultaneously during the carburizing step may be adopted.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments at all, but is merely an example and is within the scope of the present invention. Needless to say, the present invention can be embodied in various forms, and the scope of the present invention is indicated by the description of the claims, and furthermore, the equivalent meanings described in the claims, and all within the scope Including changes.

[0026]

As described in detail above, the rolling bearing according to the present invention has the following special effects. According to the first aspect of the present invention, in a rolling bearing including an inner ring, an outer ring, and a plurality of rolling elements provided in the annular space, a washer-resistant steel plate washer is fitted to an end of the inner ring. The combination prevents the occurrence of stick-slip noise, improves the assemblability and reduces the wear of the washer as compared with the conventional configuration in which a separate washer is interposed. According to the second aspect of the present invention, the washer has an L-shaped cross section, and is composed of a cylindrical portion press-fitted to the outer diameter of the inner ring and a disk portion joined to the end surface of the inner ring. Therefore, no special processing is performed on the inner ring or the washer itself, and a low-cost rolling bearing with a simple configuration can be provided. According to the third aspect of the present invention, by forming a nitrided layer on the surface of the washer by soft nitriding, the wear resistance of the washer is ensured, and deformation due to the surface treatment is suppressed as much as possible. Can be. According to the fourth aspect of the present invention, by setting the washer surface hardness to 400 Hv or more and the nitrided layer depth to 20 μm or more, the wear of the washer can be suppressed for a long period of time. According to the fifth aspect of the present invention, if a surface layer made of a solid lubricant is formed on the surface of the washer, stick-slip noise generated between the rolling bearing and the mating member can be prevented. In addition, the wear of the rolling bearing or the mating member that comes into contact with the washer can be suppressed. According to the invention as set forth in claim 6, stick-slip noise generated between a rolling bearing and a mating member such as a gear by applying to a rolling bearing rotatably supporting a gear shaft in a vehicle gear reduction device. Generation can be prevented, and wear of not only the washer but also a rolling bearing contacting the washer or a mating member can be suppressed. Therefore, the initial preload of the rolling bearing can be maintained, and good gear engagement can be maintained for a long period of time. According to the invention as set forth in claim 7, the rolling bearing has an outer ring having a conical rolling surface on an inner periphery, a conical rolling surface facing the rolling surface, and a large size of the rolling surface. A plurality of tapered rollers rotatably accommodated in an annular space between a rolling surface of an outer ring and a rolling surface of an inner ring having a large flange on an outer periphery on a radial side, and a holding device for holding the tapered rollers; Tapered roller bearings equipped with a container increases the load capacity of the bearings, and can prevent the occurrence of stick-slip noise over a long period of time even in heavy vehicles such as trucks and construction machinery. In addition, wear of the tapered roller bearing or the mating member that comes into contact with the washer can be suppressed, and maintenance-free operation can be achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rolling bearing according to the present invention.

FIG. 2 is a longitudinal sectional view of a washer mounted on the rolling bearing according to the present invention.

FIG. 3 is a left side view of FIG. 2;

FIG. 4 is a cutaway sectional view showing a conventional automobile differential.

[Explanation of symbols]

 1 Rolling bearing 2 Outer ring 2a Rolling surface 3 Inner ring 3a Rolling surface 3b・ ・ ・ ・ ・ Large collar 3c ・ ・ ・ ・ ・ ・ End face 4 ・ ・ ・ ・ ・ ・ ・ ・ ・ Rolling element 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ Cage 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ Washer 6a ・ ・ ・ ・ ・ ・・ Cylindrical part 6b ・ ・ ・ ・ ・ ・ Disc part 50 ・ ・ ・ ・ ・ ・ Housing 51 ・ ・ ・ ・ ・ ・ Tapered roller bearing 51a ・ ・ ・ ・ ・ ・ End face 52 ・ ・ ・ ・ ・ ・ Tapered roller bearing 52a ・... End face 53 Drive pinion 53a Shoulder 54 Ring gear 55 Differential gear case 56 Seat 57: Pinion flange 58: Nut 59: Washer

Claims (7)

[Claims] In a rolling bearing comprising an inner ring, an outer ring, and a plurality of rolling elements housed in an annular space thereof, it is preferable that a wear-resistant steel washer is fitted to an end of the inner ring. Rolling bearing characterized. 2. The rolling device according to claim 1, wherein the washer has an L-shaped cross section, and comprises a cylindrical portion press-fitted to the outer diameter of the inner ring and a disk portion joined to an end surface of the inner ring. bearing. 3. The rolling bearing according to claim 1, wherein a nitrided layer is formed on the surface of the washer by nitrocarburizing. 4. The rolling bearing according to claim 3, wherein the washer has a surface hardness of 400 Hv or more and a nitrided layer depth of 20 μm or more. 5. The rolling bearing according to claim 1, wherein a surface layer made of a solid lubricant is further formed on the surface of said washer. 6. The rolling bearing according to claim 1, wherein the gear shaft in the vehicle gear reduction device is rotatably supported. 7. The rolling bearing has an outer ring having a conical rolling surface on an inner periphery, a conical rolling surface facing the rolling surface, and a large flange on a large diameter side of the rolling surface. And a plurality of tapered rollers rotatably accommodated in an annular space between the rolling surface of the outer ring and the rolling surface of the inner ring, and a retainer holding the tapered rollers. The rolling bearing according to any one of claims 1 to 6, which is a tapered roller bearing.