JP4013462B2 - Hub unit for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hub unit of a type that is used on a drive wheel side by incorporating a double row rolling bearing and a constant velocity joint.
[0002]
[Prior art]
In the drive wheel type hub unit described above, for example, as shown in FIGS. 1 and 2 presented in the embodiment of the present invention, the double-row rolling bearing 2 is provided on the outer periphery of the hub wheel 1, and A constant velocity joint 3 is attached in a state of being close to the row rolling bearing 2.
[0003]
In the example shown in FIG. 1, the double row rolling bearing 2 has a single inner ring 25 having a raceway surface of a group of balls 22 in a row located on the vehicle inner side, and a row located on the vehicle outer side. The outer peripheral surface of the hub wheel 1 is used as the raceway surface of the 22 balls of the balls. However, both of the raceway surfaces have a Rockwell hardness (HRC) of 60 or more in consideration of durability. Is set.
[0004]
About the said hardening process, although heat processing including quenching and tempering is performed, by setting the said tempering temperature in the range of 150-180 degreeC, it sets to 60 or more by Rockwell hardness (HRC).
[0005]
[Problems to be solved by the invention]
In the conventional example, the heat generated from the constant velocity joint 3 is easily conducted to the vehicle inner side of the double row rolling bearing 2 because the constant velocity joint 3 is disposed in the vicinity of the double row rolling bearing 2. As a result, the inner ring 25 on the inner side of the vehicle inner side of the double row rolling bearing 2 becomes higher than the tempering temperature described above, resulting in a decrease in hardness, resulting in a decrease in heat resistance, wear resistance, rolling fatigue life, and dimensional stability. ing.
[0006]
In the case of the configuration of FIG. 2 presented in another embodiment of the present invention, the same problem as described above is pointed out. That is, in the example of FIG. 2, the outer peripheral surface of the outer ring 31 in the constant velocity joint 3 is used as a vehicle inner side inner ring of the double row rolling bearing 2.
[0007]
In view of such circumstances, the present invention provides a hub unit incorporating a constant velocity joint, and a rolling element group disposed on the raceway surface of the rolling element group disposed on the vehicle inner side of the double row rolling bearing or on the vehicle inner side. The purpose is to stabilize the quality by preventing thermal degradation of the raceway surface.
[0008]
[Means for Solving the Problems]
The first vehicle hub unit according to the present invention has a disk rotor and a wheel of a disk brake device attached to an outer surface of a radially outward flange integrally formed on the outer side of the hub wheel on the vehicle outer side, and the hub wheel In the double row rolling bearing, a constant velocity joint is attached to the outer periphery of the vehicle inner side than the flange, and a constant velocity joint is attached to the hub wheel, and heat generated by the constant velocity joint is conducted in the double row rolling bearing. The raceway surfaces of the row of rolling elements located on the vehicle inner side are hardened by heat treatment including quenching and tempering, and the tempering temperature of the heat treatment is generated from the constant velocity joint. It seems that the hardness of the raceway surface after tempering is higher than the temperature at the time of temperature rise by heat and has durability as a rolling bearing. By setting the range of 200 to 230 ° C., it is set to hardness Rockwell hardness (HRC) 6 low and 58 or more range than 0 of the track surface, and characterized in that.
[0009]
A second vehicle hub unit according to the present invention has a disk rotor and a wheel of a disk brake device attached to an outer surface of a radially outward flange integrally formed on the outer side of the hub wheel on the vehicle outer side, and the hub wheel. In the vehicle hub unit, a double row rolling bearing is attached to the outer periphery of the vehicle inner side than the flange, and a constant velocity joint is attached to the hub wheel, respectively.
The double row rolling bearing has a single inner ring having a raceway surface of a row of rolling element groups located on the vehicle inner side, and an outer peripheral surface of the hub wheel as a raceway surface of the row of rolling element groups located on the vehicle outer side. Is a configuration that uses
The raceway surface of the inner ring that is heated by the conduction of heat generated by the constant velocity joint is hardened by a heat treatment including quenching and tempering, and the tempering temperature of the heat treatment is generated from the constant velocity joint. By setting the temperature within the range of 200 to 230 ° C. so that the hardness of the raceway surface after tempering is higher than the temperature at the time of heating due to heat and having durability as a rolling bearing , The Rockwell hardness (HRC ) is set to be lower than 60 and in a range of 58 or higher.
[0011]
A third hub unit for a vehicle according to the present invention has a disc rotor and a wheel of a disc brake device attached to an outer surface of a radially outward flange integrally formed on the outer side of the hub wheel on the vehicle outer side, and the hub wheel In which a double row rolling bearing is attached to the outer periphery of the vehicle inner side of the flange, and a constant velocity joint is attached to the hub wheel, and the double row rolling bearing is a group of rolling elements located on the vehicle outer side. along with utilizing the outer peripheral surface of the hub wheel as raceway surface, a configuration using the outer peripheral surface of the outer ring in the constant velocity joint as raceway surface of the rolling element group row positioned on the vehicle inner side, wherein the constant velocity joint raising the temperature by generated heat is conducted, the raceway surface of the outer ring in the constant velocity joint quenching and tempering Teeth are hardened by heat treatment including, a tempering temperature of the heat treatment, in the constant velocity thermal temperature or higher during heating due to generated from the joint, and the hardness of the raceway surface after tempering as the rolling bearing as with durability, by setting the range of 200 to 230 ° C., and set the Rockwell hardness of the raceway surface of the outer ring of (HRC) in low and 58 or more range than 60 in the constant velocity joint, it It is characterized by.
[0013]
The fourth hub unit for a vehicle according to the present invention is characterized in that, in any one of the first to third configurations, the rolling elements of the double row rolling bearing are formed of ceramics.
[0014]
In short, in the present invention, the raceway surface of the inner ring arranged on the vehicle inner side, that is, the constant velocity joint side in the double row rolling bearing, or the raceway surface of the portion that becomes the vehicle inner side inner ring in the double row rolling bearing is subjected to the curing process. The tempering temperature is set higher than the conventional example, and the hardness is set appropriately. This enables heat resistance, wear resistance, rolling fatigue life, and dimensional stability of the raceway surface of the inner ring of the double row rolling bearing where the heat generated from the constant velocity joint is easily conducted and the raceway surface of the inner ring part. It will be raised as much as possible.
[0015]
The difference between the second configuration and the third configuration is a premise configuration as a vehicle hub unit.
[0016]
Further, if the rolling element of the double row rolling bearing is made of ceramic as in the fourth configuration, the heat resistance of the rolling element itself is improved and the heat conduction between the double row rolling bearing and the constant velocity joint is improved. Can be cut off, and a synergistic temperature rise can be suppressed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described based on embodiments shown in the drawings.
[0018]
FIG. 1 is a sectional view of a vehicle hub unit according to an embodiment of the present invention.
[0019]
The vehicle hub unit shown in the figure is a type used on the drive wheel side of an automobile, and includes a hub wheel 1, a double row rolling bearing 2, and a constant velocity joint 3.
[0020]
The hub wheel 1 has a hollow structure, a radially outward flange 11 is formed at an axially intermediate portion of the outer peripheral surface, and a female spline (not shown) is provided in a required region of the inner peripheral surface of the hollow portion. Is formed, and the raceway surface 12 of one group of balls 22 in the double row rolling bearing 2 is formed near the inner end of the outer peripheral surface.
[0021]
The double row rolling bearing 2 is composed of a single outer ring 21 having two rows of raceway grooves, a plurality of balls 22 as rolling elements arranged in two rows, and two crown-shaped cages 23. As for the two inner rings that are originally necessary, one uses the raceway surface of the hub wheel 1 as described above, and has only the other inner ring 25.
[0022]
The constant velocity joint 3 is referred to as a well-known Rzeppa type (Burfield type) constant velocity joint, and includes an outer ring 31, an inner ring 32, a ball 33, a cage 34, and the like. The outer ring 31 includes a bowl-shaped part 35 in which the inner ring 32, the ball 33, the retainer 34, and the like are accommodated and a shaft part 36 that is integrally connected to the small-diameter side of the bowl-shaped part 35.
[0023]
The double row rolling bearing 2 is attached to the outer peripheral surface of the hub wheel 1, and the shaft portion 36 of the constant velocity joint 3 is spline-fitted to the inner periphery of the hub wheel 1. The constant velocity joint 3 is attached in a state of being close to the double row rolling bearing 2 by screwing the nut 37 to the vehicle outer side shaft end.
[0024]
A disk rotor 4 and a wheel (not shown) of the disk brake device are applied to the flange 11 of the hub wheel 1 and are mounted by a plurality of bolts 13. Further, a radially outward flange 24 provided on the outer ring 21 of the double row rolling bearing 2 is bolted to the vehicle body 5 or the like. Further, the shaft 6 is spline-fitted to the inner ring 32 of the constant velocity joint 3 and is secured by a retaining ring 38 or the like. The other end of the shaft 6 is attached to a vehicle differential device through another constant velocity joint (not shown). Reference numeral 7 denotes a brake pad.
[0025]
In such a vehicle hub unit, the rotational power of the shaft 6 is transmitted to a wheel (not shown) attached to the hub wheel 1 via the constant velocity joint 3.
[0026]
By the way, in the vehicle hub unit incorporating the constant velocity joint 3 as described above, in consideration of the fact that the double row rolling bearing 2 is likely to rise in temperature due to heat generated by its operation, the thermal deterioration is prevented. The device described below is applied.
[0027]
In this embodiment, the raceway surface of the hub wheel 1 has a Rockwell hardness (HRC) of around 60, and the raceway surface in the inner ring 25 of the double row rolling bearing 2 has a Rockwell hardness (HRC) that is larger than the above value. It is characterized by being set to a low range of 58 or more.
[0028]
The hub wheel 1 is made of the following high carbon steel material, and the inner ring 25 of the double-row rolling bearing 2 is made of bearing steel such as SUJ-2 in JIS standard. The outer peripheral surface of the wheel 1 and the raceway surface of the inner ring 25 are hardened by heat treatment including quenching and tempering.
[0029]
Examples of the above-mentioned high carbon steel materials include SUJ-2, S50C, S53C, S55C in JIS standards, and 1050, 1053, 1055, 1060, 52100 in SAE standards.
[0030]
Next, with respect to the heat treatment for the hub wheel 1, first, in the quenching process, the atmosphere temperature is in the range of 780 to 900 ° C., preferably 830 ° C., for 0.5 to 3 hours. The temperature is set in the range of 150 to 200 ° C, preferably 180 ° C for 2 hours. Thereby, surface hardness can be set to HRC59-61.
[0031]
On the other hand, with respect to the heat treatment for the inner ring 25 of the double row rolling bearing 2, first, in the quenching step, the atmosphere temperature is set in the range of 780 to 900 ° C, preferably 830 ° C, for 0.5 to 3 hours, and tempered. In the step, the atmospheric temperature is in the range of 200 to 230 ° C., preferably 220 ° C., for 2 hours. Thereby, surface hardness can be HRC58-59.
[0032]
In the above-described embodiment, the heat resistance, wear resistance, rolling fatigue life, and dimensional stability on the raceway surfaces of the hub wheel 1 and the inner ring 25 are improved, so that the double row rolling bearing 2 has a vehicle inner side. On the other hand, the heat generated from the constant velocity joint 3 is conducted, so that even if the double row rolling bearing 2 is heated to, for example, 200 ° C. or more, the thermal degradation of the double row rolling bearing 2 is prevented and the quality is stabilized. Can be achieved.
[0033]
FIG. 2 is a cross-sectional view of a vehicle hub unit according to another embodiment of the present invention. In the above embodiment, the nut 37 is used to fix the shaft portion 36 of the outer ring 31 of the constant velocity joint 3 to the hub wheel 1. However, in this embodiment, the shaft portion of the outer ring 31 of the constant velocity joint 3 is used. 36 is formed in a hollow concave shape, and the shaft end is bent radially outward to be caulked against the end surface of the hub wheel 1.
[0034]
Moreover, in this embodiment, it replaces with the outer peripheral surface of the bowl-shaped part 35 in the outer ring | wheel 31 of the constant velocity joint 3, without using the single inner ring | wheel 25 with which the double row rolling bearing 2 is equipped. In accordance with this change, a contact-type seal 40 and a non-contact-type seal 50 are disposed on the vehicle inner side of the double row rolling bearing 2.
[0035]
The contact-type seal 40 has a configuration in which a lip 42 made of an elastic body is attached to a cored bar 41, and the cored bar 41 is fitted into the shoulder on the inner peripheral surface of the outer ring 21 of the double row rolling bearing 2 by press fitting. The lip 42 is in contact with the outer peripheral surface of the bowl-shaped portion 35 in the outer ring 31 of the constant velocity joint 3.
[0036]
The non-contact type seal 50 is formed of a U-shaped metal ring and is fitted into the outer peripheral surface of the bowl-shaped portion 35 of the outer ring 31 of the constant velocity joint 3 by press-fitting. An annular portion 43 extending in the axial direction is inserted in the core metal 41 of the contact-type seal 40 so as to be opposed to each other through a minute gap.
[0037]
In the vehicle hub unit having such a configuration, the constant velocity joint 3 is based on the relationship in which the raceway of the ball 22 group in one row in the double row rolling bearing 2 is the outer peripheral surface of the bowl portion 35 in the outer ring 31 of the constant velocity joint 3. The outer ring 31 is easily affected by heat.
[0038]
Therefore, in this embodiment as well, the raceway surface of the hub wheel 1 is in the vicinity of 60 in Rockwell hardness (HRC), and the outer peripheral surface of the bowl-shaped portion 35 in the outer ring 31 of the constant velocity joint 3 in this embodiment. (Surface which becomes the inner ring raceway of the double row rolling bearing 2) is characterized in that it is set in a range of Rockwell hardness (HRC) lower than the above value and 58 or more. In order to obtain this hardness, the same material and heat treatment as in the above embodiment are performed.
[0039]
In addition, all the balls 22 of the double row rolling bearing 2 are made of ceramics. As this ceramic, silicon nitride (Si ₃ N ₄ ) is mainly used, yttria (Y ₂ O ₃ ) and alumina (Al ₂ O ₃ ) are used as sintering aids, aluminum nitride (AlN), as appropriate, In addition to ceramics using titanium oxide (TiO ₂ ) and spinel (MgAl ₂ O ₄ ), alumina (Al ₂ O ₃ ), silicon carbide (SiC), zirconia (ZrO ₂ ), aluminum nitride (AlN), etc. are added To do. Specifically, for example, silicon nitride (Si ₃ N ₄ ) is the main component, yttria (Y ₂ O ₃ ) is 1.5 to 5.5 wt%, and aluminum nitride (AlN) is 1 to 2 wt. %, Alumina (Al ₂ O ₃ ) in an amount of ₂ to 4.5 wt%, and titanium oxide (TiO ₂ ) in an amount of 0.5 to 1.0 wt%.
[0040]
As described above, the outer peripheral surface of the hub wheel 1 is used as the vehicle outer side inner ring of the double row rolling bearing 2, and the outer peripheral surface of the outer ring 31 in the constant velocity joint 3 is used as the vehicle inner side inner ring of the double row rolling bearing 2. In the form, since the constant velocity joint 3 and the double row rolling bearing 2 are arranged close to each other, it can be said that heat is easily conducted to each other and the temperature rises synergistically. However, as described above, the hub wheel 1 If the hardness relation of the ridge shape portion 35 is specified, the thermal deterioration thereof is suppressed, and the heat resistance, wear resistance, rolling fatigue life, and dimensional stability of the double row rolling bearing 2 are improved. Become.
[0041]
Further, if the balls 22 of the double row rolling bearing 2 are made of ceramics as described above, the heat resistance of the balls 22 themselves is improved and heat conduction between the double row rolling bearing 2 and the constant velocity joint 3 is improved. As a result, the synergistic temperature rise can be suppressed, which is more advantageous in improving the life of the double-row rolling bearing 2.
[0042]
In addition, although various deformation | transformation is possible about the structure of the detail of the hub unit for vehicles shown by the said embodiment, this invention is applicable to all of them. Also in the embodiment shown in FIG. 1, the balls 22 of the double-row rolling bearing 2 may be formed of the above-described ceramics.
[0043]
Further, for example, in the above embodiment, the carbon steel material is subjected to normal quenching and tempering, but the heat treatment may be performed by induction heating quenching and tempering. Furthermore, alloy steel (SCr420H, SCM420H, SNCM220H, SNCM420H, SNCM815, SAE4320, SAE5120) is used for the flange 35 of the hub wheel 1, the inner ring 25 of the double row rolling bearing 2, and the outer ring 31 of the constant velocity joint 3, and carburizing and quenching them. , Tempering can be performed.
[0044]
【The invention's effect】
In the invention of claims 1 to 4, the heat resistance of about the raceway surface of the rolling element units arranged on the vehicle inner side of the double row rolling bearing, wear resistance, improve as much as possible the rolling fatigue life, dimensional stability This makes it possible to achieve a long service life.
[0045]
In particular, if the rolling element of the double row rolling bearing is made of ceramics as in the invention of claim 4 , the heat resistance of the rolling element itself is improved and the heat generated between the double row rolling bearing and the constant velocity joint is improved. Since the conduction can be cut off, the synergistic temperature rise can be suppressed, which is more advantageous in improving the life of the double row rolling bearing.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a vehicle hub unit according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a vehicle hub unit according to another embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Hub wheel 11 Flange of hub wheel 2 Double row rolling bearing 22 Ball 25 of double row rolling bearing 3 Inner ring 3 of double row rolling bearing 31 Constant velocity joint 31 Outer ring of constant velocity joint 36 Shaft part 4 in outer ring of constant velocity joint 4 Disc rotor 5 Body 6 Shaft as input shaft

Claims (4)

A disc rotor and wheels of a disc brake device are attached to the outer surface of a radially outward flange integrally formed on the outer side of the hub wheel on the outer side of the vehicle, and the hub wheel has an outer periphery on the vehicle inner side of the flange. The double row rolling bearing is also a vehicle hub unit to which a constant velocity joint is respectively attached to the hub wheel,
In the double row rolling bearing, the raceway surface of the rolling element group in the row located on the vehicle inner side, which is heated by conduction of heat generated by the constant velocity joint, is hardened by heat treatment including quenching and tempering. 200 so that the tempering temperature of the heat treatment is equal to or higher than the temperature at the time of temperature rise by heat generated from the constant velocity joint, and the hardness of the raceway surface after tempering has durability as a rolling bearing. by setting the range to 230 ° C., it is set to hardness Rockwell hardness (HRC) 6 and 58 or more in the range lower than 0 of the raceway surface, the vehicle hub unit, characterized in that. A disc rotor and wheels of a disc brake device are attached to the outer surface of a radially outward flange integrally formed on the outer side of the hub wheel on the outer side of the vehicle, and the hub wheel has an outer periphery on the vehicle inner side of the flange. The double row rolling bearing is also a vehicle hub unit to which a constant velocity joint is respectively attached to the hub wheel,
The double row rolling bearing has a single inner ring having a raceway surface of a row of rolling element groups located on the vehicle inner side, and an outer peripheral surface of the hub wheel as a raceway surface of the row of rolling element groups located on the vehicle outer side. Is a configuration that uses
The raceway surface of the inner ring that is heated by the conduction of heat generated by the constant velocity joint is hardened by a heat treatment including quenching and tempering, and the tempering temperature of the heat treatment is generated from the constant velocity joint. By setting the temperature within the range of 200 to 230 ° C. so that the hardness of the raceway surface after tempering is higher than the temperature at the time of heating due to heat and having durability as a rolling bearing , A vehicle hub unit characterized in that Rockwell hardness (HRC ) is set to a range lower than 60 and 58 or higher. A disc rotor and wheels of a disc brake device are attached to the outer surface of a radially outward flange integrally formed on the outer side of the hub wheel on the outer side of the vehicle, and the hub wheel has an outer periphery on the vehicle inner side of the flange. The double row rolling bearing is also a vehicle hub unit to which a constant velocity joint is respectively attached to the hub wheel,
The double row rolling bearing uses the outer peripheral surface of the hub wheel as the raceway surface of the row of rolling element groups located on the vehicle outer side, and the like as the raceway surface of the row of rolling element groups located on the vehicle inner side. It is a configuration that uses the outer peripheral surface of the outer ring in the speed joint,
The temperature of the outer ring in the constant velocity joint is increased by conducting heat conducted by the constant velocity joint, and the raceway surface of the outer ring in the constant velocity joint is cured by heat treatment including quenching and tempering, and the tempering temperature of the heat treatment is By setting the temperature within the range of 200 to 230 ° C. so that the hardness of the raceway surface after tempering is higher than the temperature at the time of temperature rise due to heat generated from the constant velocity joint and has durability as a rolling bearing , A hub unit for a vehicle, wherein a Rockwell hardness (HRC) of a raceway surface of an outer ring in a constant velocity joint is set in a range lower than 60 and 58 or higher. The vehicle hub unit according to any one of claims 1 to 3,
A rolling hub of the double row rolling bearing is formed of ceramics.

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